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<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: spondylodiscitis is an infection involving the intervertebral disk , the vertebral body , or the posterior arch of the vertebra .
mycobacterium tuberculosis is the most common cause of spondylodiscitis worldwide , followed by staphylococcus aureus , which is the predominant pathogen in pyogenic spondylodiscitis.1
2 even if chemotherapy is the first treatment , sometimes surgery is needed .
we report the rare case of an immunocompetent patient who underwent surgery for thoracic spondylodiscitis caused by methicillin - resistant s. aureus ( mrsa ) , which developed as a superinfection of a pulmonary tuberculous granuloma .
a 41-year - old man presented to the emergency room with dorsal back pain unresponsive to nonsteroidal anti - inflammatory drugs .
his symptoms included persistent cough , which started 6 months earlier , but he did not have a subjective history of fevers .
he was 175 cm in height and weighed 130 kg ( body mass index = 42 kg / m ) .
full blood count and biochemistry showed white blood cell count ( wbc ) 14,269/l ( neutrophils 71.3% ; lymphocytes 21.8% ; monocytes 2.2% ; wbc 4.4 to 11.3/l ) ; functional fibrinogen 907 mg / dl ( 1.5 to 4 g / dl ) ; c - reactive protein 13.86 mg / dl ( 0.1 to 6 mg / dl ) ; d - dimer 2,058 g / l ( 0 to 500 g / l ) ; ph 7.74 ; po
2 59 mm hg ; pco
2 39 mm hg ; sat o
2 95.4% .
1 ) , which revealed a lesion with a low t1- and high t2-weighted signal in the t5t6 vertebral body with high postcontrast enhancement involving the t5t6 disk and the left anterior prevertebral soft tissues .
lesion with a low t1-weighted ( a ) and high t2-weighted ( c ) signal in the t5t6 vertebral body with high postcontrast enhancement ( b ) , involving the t5t6 disk and the left anterior prevertebral soft tissues ; an epidural abscess is also evident , resulting in slight spinal cord compression .
further workup included blood cultures and computed tomography ( ct)-guided needle biopsy of the t5 vertebral body .
treatment started with rifampin 600 mg , teicoplanin 400 mg , levofloxacin 750 mg , and mobilization in an mz brace .
seven days later , the patient developed a high - grade lower - extremity weakness .
2 ) showed an increase in the size of the lesion , fracture of the inferior t5 and superior t6 end plates , and local kyphosis resulting in greater spinal cord compression .
magnetic resonance imaging scan after symptoms worsened showing an increase in the size of the lesion , inferior t5 and superior t6 end plate fractures , and local kyphosis resulting in greater spinal cord compression .
postsurgical computed tomography scan : good decompression but not complete realignment of the vertebral bodies .
seven days later , an anterior approach was used to reconstruct the anterior column and to remove the paravertebral abscess . a t5t6 corpectomy with implant of an expandable mesh and lateral plating
after lung collapse , a discolored area was identified on the surface of the lower lobe of the left lung , involving the pleura and the paravertebral tissues , and appeared contiguous with the area of the spinal abscess .
irregular area on the surface of the lung corresponding to the pyogenic abscess developed on tuberculous granuloma .
treatment was started with rifampin ( 600 mg ) , linezolid ( 600 mg ) , ethambutol ( 25 mg / kg ) , pyrazinamide ( 25 mg / kg ) , and isoniazid ( 300 mg ) .
one - year follow - up x - ray scan : good realignment of the spinal column and no other complications .
spondylodiscitis can be etiologically classified as pyogenic , granulomatous ( tuberculosis , brucellosis , or fungal infection ) , or parasitic .
pyogenic spondylodiscitis commonly affects the lumbar column and more rarely affects the thoracic and the cervical column.3
s. aureus is the predominant pathogen in pyogenic spondylodiscitis , followed in older people by enterobacteria , mainly escherichia coli , proteus , klebsiella , and enterobacter spp.4
5
6
mycobacterium tuberculosis is the most common cause of spondylodiscitis worldwide .
the main contamination routes are hematogenous spread , external inoculation , or involvement from adjacent tissue.3
early medical management is the first choice for eradicating the infection and alleviating pain.3 immobilization of the affected spine segments can protect the patient from vertebral collapse and from the appearance of neurologic deficits .
chemotherapy should be determined after microorganisms are detected.7 microbiologic diagnosis is essential to enable targeted antibiotic treatment .
agent - sensitive intravenous antibiotics should be begun preferably only after the pathogen has been identified and a table of resistance / sensitivity has been formulated.8 material taken from biopsy should undergo aerobic , anaerobic , fungal , and mycobacterial cultures .
less invasive percutaneous biopsy is a safe procedure and can be taken either by ct - guided scan or by endoscopy.9 nevertheless , biopsy and blood cultures allow microorganism identification in half of patients .
when the pathogen is not detected , empirical therapy with a broad - spectrum antibiotic regimen is appropriate.8
surgery is recommended if there is spinal cord compression , spinal epidural abscess , vertebral collapse , or deformity.10 the anterior approach is the standard for anterior vertebral body debridement and stabilization . the posterior approach is mainly indicated to decompress the spinal cord or the nerve root due to an epidural abscess.11 however , better stability is achieved with a circumferential fusion . in our case ,
the pyogenic spondylodiscitis developed as a superinfection of a pulmonary tuberculous granuloma due to a contiguous invasion of the intervertebral disk .
the best treatment for a tuberculous granuloma is surgical removal if the capsule does not allow an effective concentration of drugs in the infection 's site.12 in our case , posterior decompression was performed in an emergency setting because of the symptoms .
we decided to use an anterior approach to remove the abscess and to restore the anterior column .
moreover , in this case an anterior approach allowed us to identify the etiology of the lesion and to set the correct chemotherapy .
the patient was positioned in right lateral decubitus , and the thoracotomy was achieved via the left side to allow a good exposure and removal of the abscess that had a left extension inside the chest . the anterior approach with manubriotomy
was not considered because the lesion was below the cervicothoracic angle.13 transthoracic thoracotomy is safe and rarely associated with neurologic deterioration.14 | ### Summary:
: study design case report .
objective to describe a very rare case of an immunocompetent man who underwent surgery for thoracic spondylodiscitis caused by methicillin - resistant staphylococcus aureus ( mrsa ) that developed as a superinfection of a pulmonary tuberculous granuloma .
methods posterior decompression and pedicle screw vertebral fixation were followed by t5t6 anterior somatotomy with implant of an expandable mesh and lateral plating as symptoms worsened . during the anterior approach , an atypical resection of the left lower lobe was also performed .
results a tuberculous granuloma was detected on histology .
ziehl - neelsen stain confirmed the diagnosis .
culture also detected mrsa .
conclusions early medical management is the first choice for spondylodiscitis to eradicate the infection and alleviate pain .
immobilization of the affected spine segments can protect the patient from vertebral collapse and from the appearance of neurologic deficits .
surgery is suggested if there are compressive effects on the spinal cord , spinal epidural abscess , vertebral collapse , and deformity .
we decided to remove the abscess and to restore the anterior column using an anterior approach .
moreover , in this case , an anterior approach allowed us to identify the etiology of the lesion and to determine the best chemotherapy regimen . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: with 138 thousand people with diabetes , diabetes prevalence in oman is estimated to be 7.6% .
fear of hypoglycaemia and gain in body weight act as barriers for initiation of insulin therapy .
modern insulin analogues are a convenient new approach or tool to glycaemic control , associated with low number of hypoglycaemia and favourable weight change .
a1chieve , a multinational , 24-week , non - interventional study , assessed the safety and effectiveness of insulin analogues in people with t2 dm ( n = 66,726 ) in routine clinical care .
please refer to editorial titled : the a1chieve study : mapping the ibn battuta trail .
the patient characteristics for the entire cohort divided as insulin - nave and insulin users is shown in the table 1 .
other groups were insulin aspart ( n = 2 ) , basal insulin plus insulin aspart ( n = 38 ) , biphasic insulin aspart ( n = 121 ) and other insulin combinations ( n = 17 ) . after 24 weeks of treatment ,
overall hypoglycaemic events reduced from 1.1 events / patient - year to 0.9 events / patient - year in insulin naive group and from 12.0 events / patient - year to 3.2 events / patient - year in insulin user group .
the hypoglycaemia incidence in insulin naive group at 24 weeks was lower than that observed in insulin users at baseline .
body weight decreased and overall lipid profile improved at week 24 in complete cohort [ tables 2 and 3 ] .
overall demographic data all parameters of glycaemic control improved from baseline to study end in the total cohort . approximately , more than half of the patients achieved hba1c < 7.0% at week 24 [ table 4 ] .
overall efficacy data of the total cohort , 121 patients started on biphasic insulin aspart ogld , of which 88 ( 72.7% ) were insulin nave and 33 ( 27.3% ) were insulin users .
after 24 weeks of starting or switching to biphasic insulin aspart , hypoglycaemic events reduced from 13.4 events / patient - year to 3.9 events / patient - year in insulin user group and increased from 1.4 events / patient - year to 0.9 events / patient - year in insulin naive group . a decrease in body weight
was also observed at the end of the study [ tables 5 and 6 ] .
biphasic insulin aspartoral glucose - lowering drug safety data all parameters of glycaemic control improved from baseline to study end in those who started on or were switched to biphasic insulin aspart for both insulin nave and insulin user groups [ table 7 ] .
biphasic insulin aspartoral glucose - lowering drug efficacy data of the total cohort , 38 patients started on basal + insulin aspart ogld , of which 8 ( 21.1% ) were insulin nave and 30 ( 78.9% ) were insulin users .
after 24 weeks of starting or switching to basal + insulin aspart , hypoglycaemic events reduced from 13.4 events / patient - year to 5.2 events / patient - year in insulin user group and increased from 0.0 events / patient - year to 1.6 events / patient - year in insulin naive group .
body weight decreased at the end of the study [ tables 8 and 9 ] .
basal+insulin aspartoral glucose - lowering drug safety data all aspects of glycaemic control improved from baseline to study end in those who started on or switched to basal + insulin aspart oglds for both insulin nave and insulin user groups [ table 10 ] .
basal+insulin aspartoral glucose - lowering drug efficacy data of the total cohort , 171 patients started on insulin detemir ogld , of which 131 ( 76.6% ) were insulin nave and 40 ( 23.4% ) were insulin users .
after 24 weeks of starting or switching to insulin detemir , hypoglycaemic events reduced from 1.3 events / patient - year to 0.5 events / patient - year in insulin naive group and from 11.1 events / patient - year to 2.0 events / patient - year in insulin user group . a small decrease in body weight also observed at 24 weeks [ tables 11 and 12 ] .
insulin detemiroral glucose - lowering drug safety data all aspects of glycaemic control improved from baseline to study end in those who started on or switched to insulin detemir oglds for both insulin - nave and insulin user groups [ table 13 ] .
insulin detemiroral glucose - lowering drug efficacy data of the total cohort , 2 patients started on insulin aspart ogld and both were insulin users . similar to baseline , hypoglycaemia remained nil at 24 weeks in insulin user group . a decrease in body weight was also observed in insulin user group .
all aspects of glycaemic control improved from baseline to study end in those who started on or were switched to insulin aspart oglds for insulin user group .
of the total cohort , 121 patients started on biphasic insulin aspart ogld , of which 88 ( 72.7% ) were insulin nave and 33 ( 27.3% ) were insulin users .
after 24 weeks of starting or switching to biphasic insulin aspart , hypoglycaemic events reduced from 13.4 events / patient - year to 3.9 events / patient - year in insulin user group and increased from 1.4 events / patient - year to 0.9 events / patient - year in insulin naive group . a decrease in body weight
was also observed at the end of the study [ tables 5 and 6 ] .
biphasic insulin aspartoral glucose - lowering drug safety data all parameters of glycaemic control improved from baseline to study end in those who started on or were switched to biphasic insulin aspart for both insulin nave and insulin user groups [ table 7 ] .
of the total cohort , 38 patients started on basal + insulin aspart ogld , of which 8 ( 21.1% ) were insulin nave and 30 ( 78.9% ) were insulin users .
after 24 weeks of starting or switching to basal + insulin aspart , hypoglycaemic events reduced from 13.4 events / patient - year to 5.2 events / patient - year in insulin user group and increased from 0.0 events / patient - year to 1.6 events / patient - year in insulin naive group .
body weight decreased at the end of the study [ tables 8 and 9 ] .
basal+insulin aspartoral glucose - lowering drug safety data all aspects of glycaemic control improved from baseline to study end in those who started on or switched to basal + insulin aspart oglds for both insulin nave and insulin user groups [ table 10 ] .
of the total cohort , 171 patients started on insulin detemir ogld , of which 131 ( 76.6% ) were insulin nave and 40 ( 23.4% ) were insulin users .
after 24 weeks of starting or switching to insulin detemir , hypoglycaemic events reduced from 1.3 events / patient - year to 0.5 events / patient - year in insulin naive group and from 11.1 events / patient - year to 2.0 events / patient - year in insulin user group .
a small decrease in body weight also observed at 24 weeks [ tables 11 and 12 ] .
insulin detemiroral glucose - lowering drug safety data all aspects of glycaemic control improved from baseline to study end in those who started on or switched to insulin detemir oglds for both insulin - nave and insulin user groups [ table 13 ] .
of the total cohort , 2 patients started on insulin aspart ogld and both were insulin users . similar to baseline
all aspects of glycaemic control improved from baseline to study end in those who started on or were switched to insulin aspart oglds for insulin user group .
our study reports improved glycaemic control following 24 weeks of treatment with any of the insulin analogues ( biphasic insulin aspart ; basal + insulin aspart ; insulin detemir ; insulin aspart ) with or without ogld .
patient compliance was good with insulin analogues due to less painful injection and decreased fear of hypoglycaemia .
though the findings are limited by number of patients , still the trend indicates that insulin analogues can be considered effective and possess a safe profile for treating type 2 diabetes in oman . | ### Summary:
: background : the a1chieve , a multicentric ( 28 countries ) , 24-week , non - interventional study evaluated the safety and effectiveness of insulin detemir , biphasic insulin aspart and insulin aspart in people with t2 dm ( n = 66,726 ) in routine clinical care across four continents.materials and methods : data was collected at baseline , at 12 weeks and at 24 weeks . this short communication presents the results for patients enrolled from oman.results:a total of 349 patients were enrolled in the study .
four different insulin analogue regimens were used in the study .
study patients had started on or were switched to biphasic insulin aspart ( n = 121 ) , insulin detemir ( n = 171 ) , insulin aspart ( n = 2 ) , basal insulin plus insulin aspart ( n = 38 ) and other insulin combinations ( n = 17 ) . at baseline glycaemic control was poor for both insulin nave ( mean hba1c : 9.2% ) and insulin user ( mean hba1c : 8.8% ) groups .
after 24 weeks of treatment , both the groups showed improvement in hba1c ( insulin nave : 2.1% , insulin users : 1.6% ) .
sadrs including major hypoglycaemic events did not occur in the study patients.conclusion:starting or switching to insulin analogues was associated with improvement in glycaemic control with a low rate of hypoglycaemia and no weight gain . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the behavior of surface - tethered
biomolecules , which play key roles
throughout biology and in an increasing number of biotechnologies ,
can differ dramatically from the behavior of the same biomolecules
free in solution .
the relevant differences arise , in part , due to
stabilizing or destabilizing interactions between the biopolymer and
the surface , including excluded volume effects , electrostatic
effects , and the formation of chemo - specific surface
surface attachment can also
affect biomolecules , however , via interactions between neighboring
molecules .
previously , we explored the
former effects by experimentally determining the extent to which surface
biopolymer
interactions alter the folding free energy of a simple biomolecule
when it is attached to a set of well - defined , macroscopic surfaces . here , in contrast , we use the same system to
explore the latter effect : crowding .
several effects alter the
folding thermodynamics of biomolecules
that are crowded in solution ( see ref ( 6 ) for a recent review ) .
the excluded volume associated
with crowding agents , for example , reduces the entropy of the unfolded
molecule , thus stabilizing the native state .
conversely , the formation of specific chemical interactions
between the crowding agent and the biomolecule can occur , which can preferentially stabilize the unfolded
state .
finally , many crowding agents are also chaotropes
or kosmotropes , which alter the interaction between solvent and solute
and thus modulate , for example , the hydrophobic effect . given , however , that the effects of crowding
in solution are generally small ( typically less than 23 kj / mol )
and , more often than not , are stabilizing , it appears
that the excluded volume usually dominates , but that its magnitude
is limited by the relatively low solubility of most crowding agents .
the crowding agent concentrations that can be achieved in the surface - tethered
regime are often significantly higher than those seen in bulk solution ,
suggesting that surface - crowding effects may be more significant than
those seen in solution .
dna , for example , can be packed onto surfaces
at such high grafting densities that the effective concentration of
molecules within one contour length of the surface reaches a few tens
of percent ( w / v ) , which is more than an order of
magnitude greater than the solubility limit of dna in bulk solution . crowding on surfaces may also differ from crowding in bulk solution
due to immobilization , which limits the extent to which neighboring
molecules can diffuse away from one another to relax unfavorable interactions .
while reasonably well - explored theoretically , however , and shown empirically to affect
the performance of some technologies reliant on surface - attached biomolecules , surface - crowding effects have
not seen any significant experimental examination . in response , we
demonstrate here the extent to which crowding alters the folding free
energy of a model biopolymer attached to a well - defined macroscopic
surface .
as our model system , we have
employed a 25-base dna with self - complementary
ends .
this sequence adopts a simple stem - loop structure in the absence
of denaturant that unfolds as the concentration of the denaturant
urea rises ( figure 1 ) .
we have measured the
folding free energy of this stem - loop in four crowding regimes : ( 1 )
the dilute regime
( i.e. , largely uncrowded ) , in which
neighboring molecules are , on average , separated by a distance greater
than the contour length of the unfolded dna ; ( 2 ) the folded
crowding regime , in which the stem - loop under investigation
is crowded by a dense brush of similar , but much more stable , stem - loops
that remain folded even at the highest urea concentrations we have
employed ; ( 3 ) the unfolded crowding regime , in which
the stem - loop is crowded by a dense brush of a 25-base polythymine
sequence that remains unstructured at all denaturant concentrations ;
or ( 4 ) the homogeneous crowding regime , in which crowding
is driven by identical copies of the same stem - loop .
we tethered both
the test - bed stem - loop and the two crowding agents via their 5-termini
to a hydroxyl - terminated , six - carbon self - assembled monolayer deposited
on a gold electrode . for the case of homogeneous crowding , we can
reliably control the density with which the stem - loops are packed
on the surface . more specifically , by varying the concentration of
these various dna constructs during surface deposition over the range
of 50 nm to 2 m , we achieved surface densities from 4.7
10 to 3.3 10 molecules / cm ( supporting information figure s1 ) , which
correspond to mean nearest - neighbor separations ranging from 46 to
6.1 nm , respectively .
given the 15.5 nm contour length of the unfolded
stem - loop and assuming that , due to electrostatic repulsion and excluded
volume effects , the dna molecules achieve near maximal separation
( a supposition supported experimentally ) , these packing densities range from highly crowded to the dilute
regime in which interpolymer interactions are effectively abolished .
indeed , at the highest packing densities we have explored , the concentration
of dna molecules within one contour length ( of the folded stem - loop )
of the surface reaches 100 mg / ml ( 13 mm for oligonucleotides
of the length employed here ) , which is significantly higher than the
solubility limit of short dna oligonucleotides in solution .
for the case of the unfolded crowding agent , the reproducible control
of packing density at intermediate values is more difficult , presumably
due to repulsion between unfolded molecules ; for this system , we have
only explored a single , relatively high packing density regime ( mean
nearest - neighbor separation of 9.1 nm achieved at a deposition concentration
of 2 m ) . because the effects of a folded crowding agent are
relatively small even under highly crowding conditions ( mean nearest - neighbor
separation of 6 nm ) , for these studies , we likewise only explored
the most highly packed regime . to explore the thermodynamic consequences
of crowding for surface - tethered
biomolecules ,
we have measured the folding free energy of ( top ) a
simple dna stem - loop attached by one terminus to a hydroxyl - terminated ,
six - carbon thiol - on - gold self - assembled monolayer ( sam ) . a redox - active
methylene blue reporter on its distal terminus provides a means of
monitoring the unfolding of the stem - loop using ( bottom ) square - wave
voltammetry .
recovery of the original peak height after urea - induced
unfolding and subsequent refolding illustrates the reversibility of
folding under the experimental conditions we have employed . to measure folding free energy ,
we modify our stem - loop with a
terminal methylene blue redox reporter and use square - wave voltammetry
to monitor the fraction of these molecules remaining in the stem - loop
configuration as we titrate in urea .
such urea - melt data are traditionally
fitted by assuming a linear relationship between free energy and denaturant
concentration:1where [ urea ] is the concentration
of the denaturant , i , if , and iu are the experimentally observed
signal ( here the observed peak current ) and the ( fitted ) signals arising
from the fully folded ( if ) and fully unfolded
states ( iu ) , respectively , g is the standard free energy of folding in
the absence of denaturant , and m is the denaturant
strength and describes the relative change in folding free energy
per 1 m change in denaturant concentration .
( of note , as is also true
when the urea - induced unfolding of biomolecules is measured optically
via circular dichroism or intrinsic fluorescence , if and iu are linearly dependent on urea concentration in our experiments ;
see figure s1 for examples of raw urea unfolding data . ) using this
approach , we have previously shown that ,
in the absence of crowding ( i.e. , in the dilute regime ) , the folding
free energy of the stem - loop is 6.7 0.8 kj / mol ( all
reported error bars reflect 95% confidence intervals derived from
multiple , independent replicates ) .
this represents slightly lower
stability than that observed in solution under these same conditions ,
an effect that we attribute to electrostatic repulsion from the gold
surface , which is negatively charged at
the redox potential of the methylene blue reporter . being in
the folding crowded regime destabilizes
our stem - loop ( figure 2 ) . to show this
, we
co - deposited the stem - loop ( in the dilute regime ) with a 20-fold excess
( in the deposition solution ) of a more stable stem - loop ( which remains
folded at even the highest urea concentrations we employ ) to ensure that , while each stem - loop is surrounded
by a dense brush of always - folded molecules , neighboring test - bed
stem - loops are generally too far apart to interact with one another .
at a total packing density of 3(1 ) 10 molecules / cm , which corresponds to a mean nearest - neighbor separation
of 6 1 nm , the stability of our stem - loop is 4.7
0.8 kj / mol , which is 2 kj / mol less stable than the same stem - loop
in the dilute regime .
we presume this destabilization
arises because the charge density within one ( folded ) contour length
of the surface is extremely high under these conditions .
if a single
chain unfolds and expands such that much of its length is well above
this highly charged brush of folded neighbors , this will reduce the
charge density at the surface leading , in turn , to ( enthalpic ) stabilization
of the unfolded state .
conversely , crowding by neighboring chains
reduces the extent to which this unfolded chain can expand ( relative
to the dilute regime ) , an effect that should , in contrast , ( entropically ) destabilize the unfolded state .
given the observed destabilization ,
it appears that the former effect ( enthalpic , charge - density - linked
stabilization of the unfolded state ) dominates over the latter effect
( entropic destabilization of the unfolded state ) for the system we
have studied . in bulk solution ,
crowding generally stabilizes the more
compact
native state . on a surface , in contrast
shown is the
urea - induced unfolding of a methylene - blue - modified stem - loop ( in
the dilute regime , i.e. , with each too far , on average , from its like
neighbors to interact ) when ( red ) crowded with a highly stable stem - loop
that remains folded throughout the experiment , ( black ) in the dilute
regime ( no crowding ) , or ( blue ) when crowded with a polythymine
construct that remains unfolded throughout the experiment . whereas
crowding by other folded stem - loops is destabilizing
( by 2 kj / mol ) , crowding by unfolded chains
strongly stabilizes
the folded stem - loop ( by 6 kj / mol ) . of note ,
neither of these
crowding regimes alters the width of the unfolding transition , which
is a measure of the m value ( i.e. , denaturant strength ) :
the best - fit m values in all three regimes are within
error of the 2.1 kj / mol / m value seen in ( dilute ) bulk solution .
in contrast to crowding by folded neighbors , being in the
unfolding
crowding regime increases the stability of our test - bed
stem - loop ( figure 2 ) . to see this ,
we co - deposited
the stem - loop ( again , being deposited at conditions that would render
it in the dilute regime ) with a 20-fold ( solution phase ) excess of
inert , unfolded polythymine constructs of the same length . under
these conditions ,
specifically ,
at a ( total ) packing density of 9(3 ) 10 molecules / cm ( corresponding to a mean nearest - neighbor separation of just
11 2 nm between adjacent dna molecules ) , the stability
of the stem - loop reaches 12 4 kj / mol .
while this increase
in stability presumably arises due to the same electrostatically and
sterically driven excluded volume effects postulated to underlie solution - phase
crowding , its magnitude is rather greater
than the effects typically seen in solution .
this difference may arise in part due the high local concentrations
of dna that can be achieved in the surface - bound state , which approach
100 mg / ml within one contour length ( the 15 nm length of the unfolded
dna chain ) of the surface .
this said , the stability of proteins ( in the dilute regime ) typically increases by only 1 kj / mol
with the addition of 100 mg / ml of highly soluble , nonbiomolecular
crowding agents , such as polyvinylpyrrolidone or dextran , suggesting
that additional mechanisms may be playing a role in our results .
because
the polythymines we employ here as our crowding agent are , like
the stem - loop , negatively charged , electrostatic repulsion may account
for this discrepancy , as electrostatic repulsion between unfolded
chains would reduce their entropy beyond the reductions produced by
steric - excluded volume effects alone .
theory suggests , however , that the fixed relative positions ( and
perhaps common orientations ) of the surface - bound dna strands could
also enhance the entropic effects of crowding on the surface relative
to those seen in bulk solution .
the homogeneous crowding regime ( crowding by other
foldable stem - loops ) differs from heterogeneous crowding
( crowding by always - folded stem - loops or always - unfolded polythymine )
in producing a broader unfolding transition ( figure 3 ) .
this may arise because the extent of crowding in this regime
is dependent on urea concentration . specifically , at low denaturant ,
the test - bed stem - loops are crowded by adjacent , folded stem - loops ,
which , as shown above , is destabilizing . as the urea
concentration rises , however , any stem - loop that remains folded will
be crowded by unfolded neighbors , which , as shown above , is stabilizing . thus , as each additional stem - loop unfolds ,
the next becomes more stable , an
unfortunately ,
such anti - cooperative behavior invalidates the linear ( in urea concentration )
free - energy relationship assumed in eq 1 , preventing
us from accurately determining the stability of the surface - bound
stem - loop under these homogeneous crowding conditions .
homogeneous crowding
( purple ) , i.e. , crowding by other copies of
the same , relatively unstable stem - loop , broadens the unfolding transition
relative to that seen when the stem - loop is crowded by either always - folded
( red ) or always - unfolded ( blue ) molecules ( the latter curves taken
from figure 2 ) .
this presumably occurs because
the stabilizing effect of crowding by unfolded neighbors increases
and the destabilization caused by folded neighbors decreases as more
and more of the chains unfold .
shown are unfolding data collected
at a mean separation of 6 nm between adjacent chains .
the broader transition seen for homogeneous crowding
by our test - bed
stem - loop is reflected in its effect on the observed m value , a measure of the strength of the denaturant . in solution , m values
are strongly correlated with the solvent - accessible
surface area liberated in the folding transition . given this , and given that even our most densely packed
surfaces are likely too sparsely packed to affect the solvent - accessible
surface area of the unfolded stem - loop
consistent with this , the m values we observe upon crowding with both folded and unfolded
crowding agents are both within error of the value seen in the dilute
regime ( 2.6 0.6 , 2.4 0.3 , and 2.4 0.2 kj / mol / m ) .
all of these m values are likewise within error of
the 2.1 0.2 kj / mol / m m value seen in bulk
solution .
in contrast , however , the best - fit m value we observe under the most highly homogeneously crowded
regime is just 1.1 0.3 kj / mol / m , reflecting the much broader
transition we observe under these conditions ( figure 3 ) . given that m values are , generally ,
inversely
proportional to the change in solvent - accessible surface area upon
unfolding , the reduced m value we observe under these conditions could be indicative of an
unfolded state that is less unfolded ( i.e. , less solvent - accessible
surface area is exposed ) .
this could arise , for example , due to the
formation of intermolecular base pairing at low urea , which
could produce heterogeneity of the folded state .
we believe
this scenario unlikely , however , because , even at the highest packing
densities we have explored , the chain would have to be rather extended
in order for the complementary regions of adjacent chains to interact .
interchain hybridization would thus be both entropically ( because
the chain is highly extended ) and enthalpically ( because the chain
is forced closer to the negatively charged surface ) unfavorable .
we
believe instead that the reduction in the apparent m value arises due to broadening of the unfolding transition caused
by the anti - cooperative unfolding behavior described above .
consistent
with this , when the packing density is low enough that neighboring
chains no longer interact , the observed m value approaches
the value seen in bulk solution ( figure 4 ,
top ) .
( top ) naively assuming a linear relationship between folding free
energy and urea concentration ( eq 1 ) suggests
that the m value ( a measure of denaturant strength )
for unfolding is strongly dependent on packing density under these
crowding conditions .
the fitted m value approaches
that seen in solution ( and in the case of crowding by either always - folded
or always - unfolded neighbors , figure 2 ) ; however ,
the packing density falls low enough that neighboring molecules no
longer interact .
( bottom ) similarly , the calculated folding free energy
approaches the value seen for dilute surface coverage when the packing
density falls below this interaction distance .
the crowding effects we have observed for surface - tethered
biomolecules
are larger and somewhat more complex than those generally seen in
bulk solution .
it appears , for example , that crowding on a surface
can flip from stabilizing to destabilizing depending on the structure of the crowding agent even when its chemistry
is effectively held fixed , with the effects reaching several kilojoules
per mole as the effective concentration of the crowding agent increases
from the dilute limit to 100 mg / ml .
this is in contrast to
crowding effects in solution , which generally affect stability by
less than 1 kj / mol .
the effects seen in the surface - bound regime thus offer new insight
into the consequences of crowding .
it likewise illustrates , once again ,
the significant and often complex effects that surface attachment
can have on the physical properties of biopolymers .
the dna oligonucleotides
employed were synthesized by bio - search
technologies ( novato , ca ) and purified by anion exchange hplc followed
by reverse - phase hplc .
the model stem - loop sequence employed is 5-act
ctc gat cgg cgt ttt aga gag g-3. the polythymine sequence
used to produce heterogeneous crowding is 25 bases .
the sequence of
the highly stable stem - loop used in the semi - homogeneous crowding
regime is 5-acg cgc gat cgg cgt ttt agc gcg g-3. all
three sequences were modified with a six - carbon thiol on their 5-termini .
the model stem - loop sequence was also modified with a methylene blue
attached via amide bond formation to a six - carbon amine on its 3-terminus . as the gold surface
, we employed polycrystalline gold disk
electrodes ( 2 mm diameter ; bas , west lafayette , in ) .
these were electrochemically
cleaned as previously described . in brief ,
the cleaning consists of a series of oxidation and reduction cycling
in ( 1 ) 0.5 m naoh ( 0.4 to 1.35 v ) , ( 2 ) 0.5 m h2so4 ( 02 v ) , ( 3 ) 0.5 m h2so4 ( 0 to 0.35 v ) , ( 4 ) 0.5 m h2so4 ( 0.35 to + 1.5 v ) , and finally ( 4 ) 0.01 m kcl/0.1 m h2so4 ( 0.2 to + 1.25 v ) . the clean gold electrode
surface was modified with the relevant oligonucleotide(s ) by
incubation for 5 min at room temperature in a solution of the thiol - terminated
dna . for homogeneous packing , the relevant oligonucleotide was
used at concentrations ranging from 50 nm to 2 m ( depending
on the desired packing density ) in 20 m tris(2-carboxyethyl)phosphine
hydrochloride to reduce any disulfide bonds and 30 mm nacl in
20 mm phosphate buffer ph 7 . for heterogeneous and semihomogenous
packing ,
the model stem - loop sequence was used at 50 nm in 30 mm nacl
in 20 mm phosphate buffer ph 7 for 5 min , then the polythymine
sequence or the highly stable stem - loop sequence was used at 2 m
in 150 mm nacl in 50 mm phosphate buffer ph 7 for 2 h , increasing
salt concentration to increase screening interactions and thus the
possible packing density .
the resulting dna - modified surface was washed
with deionized water before being treated with 2 mm 6-mercapto-1-hexanol
overnight to complete the formation of the sam .
reported packing densities are means and standard errors
determined by making multiple independent measurements on each surface .
we determined folding free energies using urea melts generated
either with a hamilton 500c titrator or by manual titrations starting
at 10 m urea in buffer ( 20 mm sodium phosphate ph 7 , 30 mm sodium
chloride ) and titrating in the same buffer lacking urea . at each urea
concentration
, the system was allowed to equilibrate for 30 s after
mixing prior to measurement .
electrochemical measurements were conducted
using square - wave voltammetry from 0 to 0.5 v at a frequency
of 60 hz on either a chi 630 potentiostat ( ch instruments , austin ,
tx ) or a palmsens ( palmsens bv , the netherlands ) in a standard cell
with a platinum counter electrode and a ag / agcl ( saturated with 3
m nacl ) reference electrode . prior to use , each electrode was washed
with 10 m urea in buffer , washed again with buffer , and then incubated
in 10 m urea for at least 1 h prior to the start of the titration .
to determine the folding free energy , a plot of peak current ( at the
260 mv potential of methylene blue ) versus urea concentration
was fitted to a standard two - state unfolding curve with linear , sloping
baselines . | ### Summary:
: the high packing densities and fixed
geometries with which biomolecules
can be attached to macroscopic surfaces suggest that crowding effects
may be particularly significant under these often densely packed conditions .
exploring this question experimentally ,
we report here the effects
of crowding on the stability of a simple , surface - attached dna stem - loop .
we find that crowding by densely packed , folded biomolecules destabilizes
our test - bed biomolecule by 2 kj / mol relative to the dilute
( noninteracting ) regime , an effect that presumably occurs due to steric
and electrostatic repulsion arising from compact neighbors .
crowding
by a dense brush of unfolded biomolecules , in contrast , enhances its
stability by 6 kj / mol , presumably due to excluded volume and
electrostatic effects that reduce the entropy of the unfolded state .
finally , crowding by like copies of the same biomolecule produces
a significantly broader unfolding transition , likely because , under
these circumstances , the stabilizing effects of crowding by unfolded
molecules increase ( and the destabilizing effects of neighboring folded
molecules decrease ) as more and more neighbors unfold .
the crowding
of surface - attached biomolecules may thus be a richer , more complex
phenomenon than that seen in homogeneous solution . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: over the last two decades , there has been a substantial increase in our understanding of the underlying biology of bone metastasis as well as the development and widespread incorporation of inhibitors of osteoclast function , namely bisphosphonates and denosumab , into clinical practice , , . however , more recently there has been an international fall in peer - reviewed grant funding .
this trend is also clearly evident in the declining grant support provided by the three canadian federal funding agencies ( canadian institutes of health research ( cihr ) , natural sciences and engineering research council of canada ( nserc ) and social sciences and humanities research council ( sshrc ) .
( bonus ) meeting is an annual canadian multidisciplinary conference on the interaction of bone and cancer biology , .
the focus of the 2015 bonus conference ( 16 and 17 april 2015 ) was to discuss potential key research themes that could form the basis for a coordinated national research strategy to tackle unmet clinical and research needs related to complications associated with cancer metastasis to bone .
this article captures a two - day programme of multidisciplinary presentations , panel discussions and interactive dialogue on planning a national strategy for bone metastasis research .
we aimed to review the data on bone pain management , expand our capacity to address current and future development challenges , place strategies in the context of the widespread use of bone - targeting agents and to act as a forum for feedback and comments from other researchers interested in this field .
prior to the bonus 2015 meeting a preliminary meeting was held in montreal in november of 2014 .
the working group felt that the development of specific research questions focused on
bone metastasis should be formulated from the starting point of unmet clinical needs . in particular , the following issues were felt to be of key importance : understanding the biology associated with the process of bone metastasis initiation and progression and developing potential treatment strategies to improve outcome of patients with bone metastases .
there was also a strong feeling that research initiatives should incorporate questions that cut across the cancer care continuum from basic biomedical research to clinical translation and patient outcomes .
based on the priorities discussed during the preliminary meeting , the following themes were selected for in - depth discussion at the 2015 bonus meeting : is bone metastases - related pain the main issue facing patients ? are there new therapeutic targets for patients with bone metastases ?
each of these themes will be summarised below.theme 1 : is bone metastases - related pain the main issue facing patients ? : is bone metastases - related pain the main issue facing patients ? this session consisted of presentations about metastasis - related bone pain from the perspectives of patient experience and clinical care.what are the current limitations of bone - targeted agents in relation to bone pain in patients with bone metastases ? eitan amir , md
what are the current limitations of bone - targeted agents in relation to bone pain in patients with bone metastases ?
eitan amir , md while any malignancy may metastasise to bone , it is most prevalent in advanced breast ( 7080% ) , prostate ( 7080% ) , thyroid ( 60% ) , lung ( 1050% ) and renal cancers ( 30% ) , , , , .
the consequences of bone metastases include reduced survival , morbidity and pain that negatively affect the patient 's quality of life ( qol ) as well as skeletal - related events ( sres ) , . despite the fact that randomized trials of bisphosphonates , and denosumab , have shown reduced incidence of sres , prolonged time to occurrence of sres and an improvement in pain control , clear improvements in overall quality of life ( qol )
two trials comparing pamidronate to placebo showed that patients in the pamidronate arms experienced less pain ; however , there was no difference in the overall qol . similarly , in the randomized trial comparing denosumab to zoledronic acid , improvements in qol were observed in both arms with denosumab not showing consistently greater magnitude of improvement over the entire trial period . whether qol improvements resulted from the administration of bone targeted therapy or the concurrent administration of systemic anti - cancer therapy is unclear especially as the placebo - controlled randomized trials of bisphosphonates did not show differences in qol between arms , given that bone - targeting agents have not been found to affect overall or progression - free survival and have known risks and adverse effects , including rare but severe toxicities such as hypocalcaemia and osteonecrosis of the jaw ( onj ) , ,
, this lack of improvement in qol is disappointing . as we have likely reached the limits of therapeutic osteoclast inhibition with bisphosphonates and denosumab
there is increasing interest in the effects of other anti - cancer agents on the bone .
for example , the use of new treatments for prostate cancer such as abiraterone acetate , enzalutamide and radium 223 have all shown decreased rates of sres as well as improvements in survival . as a result
, there is a need to develop better agents not only to reduce bone pain but to also identify strategies to optimise the use of bone - targeted agents as sres become less common .
as more effective cancer treatments become available , it will be important to further explore optimal dosing of bone - targeting agents in these patients.what do patients with bone metastases need ?
virginia jarvis , rn virginia jarvis , a nurse specialist in pain and palliative care , followed up with a discussion of known as well as poorly understood needs of patients with bone metastases in ambulatory and palliative care .
pain assessment for patients with bone metastasis presents unique problems as pain is often incidental in nature with high pain scores with movement and minimal to zero pain scores at rest making the standard 010 verbal scoring system an ineffective tool .
the brief pain inventory was discussed as a pain assessment instrument that could best inform health care professionals to the actual pain state and help guide the clinician to the choice of appropriate treatments that may include interventional therapies that go beyond the world health organisation analgesic ladder .
indeed , in a large recently presented study , risk of sres was correlated with worsening pain scores on the brief pain inventory .
the unmet needs of patients include treatments such as physiotherapy , occupational therapy and social work as pain effects mobility , activities of daily living , the ability to drive and financial decline .
following this presentation there was extensive discussion around whether bone pain was the major issue facing patients or reduced mobility .
this could be an important direction for future studies and requires further evaluation.what are orthopaedic surgeons doing in 2015 for patients with painful bone metastases ?
joel werier , md orthopaedic stabilisation of osseous metastatic lesions can provide rapid and effective pain relief in patients presenting with significant bone destruction and impending or pathologic fracture .
it is essential to develop a collaborative relationship between engaged orthopaedic surgeons and medical as well as radiation oncologists in order to facilitate multidisciplinary care of an individual patient . a clear understanding of life expectancy , patient expectations , and tumour biology can help guide clinical and surgical decision making .
for example , orthopaedic interventions could be significantly altered if it was evident that a patient had a very short prognosis .
minimally invasive techniques such as radiofrequency ablation , percutaneous cryoplasty , cementoplasty , and vertebroplasty can be effective in patients who are poor surgical candidates or who have a specific lesion that can be addressed by these techniques .
surgical stabilization is almost always supplemented with radiation to minimise tumour progression and implant failure . a collaborative approach with orthopaedic surgical consideration
can greatly aid in the palliation , mobilisation , and quality of life of affected individuals .
basic and translational researchers should be invited to collaborate with clinicians caring for patients with metastatic bone disease .
for example is local delivery of biologics , incorportated into scaffods / cements used to stabilise surgical defects a useful approach ?
in addition , in our centre orthopaedic stabilization with tumour de - bulking is a unique opportunity to provide good quality tumour specimens for basic science and translational research investigating novel therapies.study endpoints in trials of bone - targeted agents and radiotherapy should bone pain be a criteria ? kris denis md and mark clemons , md
study endpoints in trials of bone - targeted agents and radiotherapy should bone pain be a criteria ? kris denis md and mark clemons , md traditionally , bisphosphonates have been evaluated in terms of sre prevention ; however , its definition has changed with time .
for example , while older studies included hypercalcaemia as an sre , most subsequent trials do not take it into account .
second , clinical trials often mandate bone surveys and isotope bone scans every 3 months , resulting in the detection of asymptomatic sres . including these asymptomatic events
as endpoints makes it challenging to determine whether newer agents actually represent an improvement in preventing what truly matters to patients : symptomatic sres , , .
another factor limiting the use of sres as a meaningful endpoint is that bone pain per se is not considered a sre despite the fact that clearly impacts patient qol and is tied to the use of radiotherapy .
indeed , the conditions under which radiotherapy has been indicated ( and recorded as a sre in previous trials ) are not standardized . indeed , a review of literature and survey on qol perception outcomes of radiation therapy for bone metastasis has shown that the impact of metastatic disease and radiotherapy extends beyond pain . looking beyond simple endpoint metrics , perhaps an alternative way to measure
the impact of bone metastases on patients is through a broader examination of qol impact .
the european organisation for research and treatment of cancer ( eortc ) quality of life group bone metastases module ( eortc qlq bm22 ) is a bone metastases- specific instrument that measures the impact of bone metastases on patients quality of life .
it has been extensively validated internationally and is well - suited to use within clinical trials .
conclusion 1 : given that pain / mobility remains a significant issue for many patients , the group felt the first priority for future studies should be to investigate the experience in patients with bone metastatic cancer with regard to pain , mobility , fatigue , psychological distress , reduced performance and treatment side - effects .
it will only be possible study the impact of all these issues in the individual patient with a dedicated bone metastasis health - related qol tool.theme 2are there new targets for patients with bone metastases ? are there new targets for patients with bone metastases ?
the second session involved presentations discussing the strategies and ideas in development of new treatment strategies for patients with bone metastases.better use of established agents ? mark clemons , md better use of established agents ? mark clemons , md one of the ways to improve therapeutic outcomes would be to use current agents more effectively , . given that patients with bone - only metastatic disease may experience longer term survival , and the risk of adverse events from bone - targeting agents increases with cumulative exposure , the question around optimal dose and dosing interval remains unanswered , , .
a survey of physicians who treat patients with bone metastases from breast cancer and metastatic castration - resistant prostate cancer showed significant variability in the use of bone - targeting agents , including the choice and dosing interval .
a systematic review evaluating de - escalated treatment ( i.e. every 12 weeks ) of breast cancer patients with bone - targeted agents in comparison to current standard practice of every 34 weeks showed a clear knowledge gap with regard to establishing the clinical benefits of de - escalated bone targeted agent therapy in metastatic breast cancer patients .
similarly , a recent systematic review also demonstrated that denosumab 12-weekly was as effective as 4-weekly dosing in patients with bone metastases from prostate cancer ( in press ) .
integration of these reduced frequencies of bone - targeted agents into routine clinical practice could benefit both patients ( reduced visits to the cancer centre for treatment and less drug toxicity ) and the health care system ( lower drug costs ) . for many years
it has been hoped that use of biochemical endpoints , such as bone resorption markers , may offer a solution to the challenge of using pain scores by offering a quantitative , rather than qualitative , assessment of bone - targeting agent effect on the bone in the presence of skeletal metastases .
retrospective analyses of bisphosphonate trials suggest that early normalisation ( at 3 months ) of urinary n - terminal telopeptide levels in patients undergoing treatment with bisphosphonates are associated with a significantly reduced risk of a first sre , first fracture , surgery to bone , or death . however , incorporation of these biomarkers of bone turnover , pain scores and sres to develop practical strategies to improve the care of patients has to date been extremely challenging , , .models for bone metastases christina addison , phd
models for bone metastases christina addison , phd there are a number of pre - clinical animal models to study cancer metastasis to bone . typically , approaches are employed that include syngeneic , transgenic and xenograft models of bone metastasis . experimentally , the most frequent route of injection of cancer cells is intracardiac ( into left cardiac ventricle ) , which permits seeding and colonisation of tumour cells in metaphyses of the long bones .
intratibial ( intraosseous ) injection of tumour cells directly into the marrow space is often used to examine tumour stromal interactions during the growth of bone metastatic lesions .
finally , vossicle models are emerging in which foetal human bone is implanted subcutaneously into mice , followed by intra - cardiac or local injection of human tumour cells that colonise the human bone fragments and form metastases .
histological and immunhistochemical techniques are employed to study excised tissues while increasingly , in vivo imaging modalities ( optical imaging systems ( ivis ) , radiography , ct and mri ) have been used to assess the growth of bone metastatic lesions and the effect on bone resorption / destruction . while these models have been very useful in delineating mechanisms that drive the colonisation and growth of cancer cells in bone , they have not been interrogated sufficiently .
hopefully these models can be utilised further to identify novel therapeutic targets and develop more effective treatment combinations that could enhance overall survival.new targets john hilton , md new targets john hilton , md a series of potential emerging agents may be helpful in addressing bone - only disease .
cabozantinib ( xl184 ) is an orally bioavailable tyrosine kinase inhibitor with potent activity against met and vegfr2 . in early clinical studies in patients with metastatic prostate cancer
, cabozantinib demonstrated significant and rapid effects on bone scan lesions as well as on markers of bone formation and resorption , bone pain and narcotic use .
in addition , statistically significant improvement in progression - free survival was seen with cabozantinib compared with placebo .
while the subsequent larger registration study was negative in terms of overall survival , it again showed important findings in metastatic bone disease , including resolutions of metastases in bone scans and reductions in bone turnover markers .
it is possible that the observed clinical effects on bone are related to decreased rankl expression in osteoblastic cells and inhibition of osteoclastogenesis and pthrp - stimulated bone resorption , thus providing a rationale for beneficial skeletal observations while failing to control progression of the malignancy .
it is also possible that cabozantinib should not be considered a bone - targeting agent per se , but as an effective anti - tumour agent given its efficacy in metastatic renal cell cancer . given the effects of cabozantinib on bone metastases in patients with castration resistant prostate cancer it would be interesting to see whether or not combinations with bisphosphonates or denosumab are synergistic or not.radium 223 as a novel therapeutic for bone metastases urban emmenegger , md radium 223 as a novel therapeutic for bone metastases urban emmenegger , md radium 223 is a calcium mimetic alpha emitter that selectively binds to areas of increased bone turnover such as bone metastases . in patients with castration - resistant prostate cancer , radium 223
qol was also seen to be better with radium 223 versus placebo . since radium 223 is the first bone - targeted agent with documented positive impact on overall survival . as with cabozantinib ,
mentioned above , it is also possible that as radium 223 delivers radiation to the bone metastases itself it should also be considered an anticancer agent and not just a bone - targeted agent .
results in other tumour types such as breast cancer are eagerly awaited.immune therapies for bone metastases guy ungerechts , md immune therapies for bone metastases guy ungerechts , md targeted infection of cancer using novel oncolytic viral therapies via binding of tumour - specific surface receptors is an exciting and promising field .
therapy combining oncolytic virus with an immune checkpoint blockade for immunovirotherapy can lead to an immunomodulation and ultimately disease response .
while immunomodulation may prove to be extremely important for effective tumour control in the bone microenvironment , tumour - specific receptors for bone metastatic lesions remain less well characterized.theme 2 conclusion : despite over two decades of widespread use of osteoclast - targeting agents such as bisphosphonates and more recently denosumab these have had no discernible effect on response rates , progression free or overall survival .
studies on dosing intervals with osteoclast - targeting agents continue to show that treatment can be safely de - escalated and studies are needed to explore their role in the presence of increasingly effective anti - cancer agents .
studies will need to integrate basic science models into clinical practice so that novel agents and their combinations can be more rapidly evaluated in the laboratory before performing large , expensive studies in patients.theme 3how do we more firmly link basic science with clinical practice ? : despite over two decades of widespread use of osteoclast - targeting agents such as bisphosphonates and more recently denosumab these have had no discernible effect on response rates , progression free or overall survival .
studies on dosing intervals with osteoclast - targeting agents continue to show that treatment can be safely de - escalated and studies are needed to explore their role in the presence of increasingly effective anti - cancer agents . however ,
studies will need to integrate basic science models into clinical practice so that novel agents and their combinations can be more rapidly evaluated in the laboratory before performing large , expensive studies in patients .
it is evident that there has to be meaningful collaboration between basic science and clinical practice . in the final session ,
bone metastasis models and their limitations were discussed . finally , clinicians presented information on future directions in the bone metastasis research field .
it was hoped that this would provide additional information for basic science collaboration.animal models for bone cancer - induced pain svetlana v. komarova , phd animal models for bone cancer - induced pain svetlana v. komarova , phd one of the factors limiting research into the area of bone cancer - induced pain is the limited number of animal models where treatment hypotheses can be tested . dr komarova presented data on the behavioural pain phenotype in an experimental breast cancer bone metastasis model and on the pain - relieving effects of microenvironment - targeting adjuvant therapies . in a mouse model , where immunocompetent mice were injected intra - tibialy with murine mammary carcinoma cells or saline ,
breast cancer bone metastasis was associated with gradual development of osteolysis , spontaneous limping and guarding of affected limbs , as well as a significant increase in the sensitivity to mechanical , heat and cold stimuli .
moreover , unilateral breast cancer bone metastasis was found to drive hypersensitivity , bone remodelling and sensory neuronal plasticity at sites distant from the tumour area .
the anti - inflammatory and osteolysis - targeting drug rapamycin reduced hypersensitivity to mechanical and thermal stimuli in the cancer - bearing and contralateral limbs , while the osteoclast - targeting drug pamidronate reduced thermal sensitivity at the cancer - bearing and contralateral limbs .
thus , localised bone cancer drives osteolysis , sensory hypersensitivity , and neuroplasticity both locally and distantly from the primary lesion .
ultimately mechanistic based therapeutics is essential to develop novel agents for cancer induced bone pain .
unfortunately , despite the promise of these models , there are difficulties in translating these studies to patient experience .
first , while pain assessment in patients is generally done using validated questionnaires , such tools are not practical in animal studies .
in contrast , quantitative sensory tests which assess the sensitivity thresholds to mechanical and thermal stimuli can be used in humans and animals , and were shown to be informative and predictive in patients with neuropathic and musculoskeletal pain , , as well as chemotherapy - related pain in cancer patients , .
however , the validity of quantitative sensory tests in providing measurable pain information in bone metastasis patients has been only assessed in a small number of patients , making it impossible to translate pain - related conclusions obtained in animal studies to patient care .
in addition , the treatment protocol in experimental animals commonly does not reflect the usual treatment protocol in patients such as use of clinically relevant chemotherapy dosing schedules and time delay between initiation of bone metastasis and development of symptoms which will lead to treatment in patients .
thus , development of direct correlates between measures used to quantify the disease progression in animal models and in patients will help in knowledge translation from basic science studies to clinical care.challenges of ex - vivo models for identifying new targets christina addison , phd challenges of ex - vivo models for identifying new targets christina addison , phd a significant limitation of the use of cell lines in breast cancer bone metastasis related research has been the fact that so many cell lines are from hormone receptor negative lines , when the vast majority of patients have hormone receptor positive disease .
addison and her team have therefore established a programme in collaboration with orthopaedic surgeons to obtain tumour tissue straight from the operative room from patients undergoing surgery for bone metastases complications . as a result , it is possible to isolate new bone metastatic - derived cancer cell lines , to test drug combinations in ex vivo bone metastatic tumour tissues and to develop patient derived xenograft models .
there remain challenges in translating these models into the clinical practice , such as a need to improve quantitative assays for tumour burden and ultimately evaluate response to treatment in vivo and models that can better mimic to the human in vivo phenotype.bisphosphonates as adjuvant therapy for breast cancer and the relevance of the low estrogen environment alexander paterson , md bisphosphonates as adjuvant therapy for breast cancer and the relevance of the low estrogen environment alexander paterson , md since bisphosphonates were found to benefit patients with bone metastases from breast cancer , trials of adjuvant bisphosphonates in operable primary breast cancer were set up in the 1990s and early 2000s , some using end - points appropriate for a class of drugs whose dominant mode of action is in bone ( e.g. bone metastasis - free interval and overall survival [ os ] ) , and others , using traditional cancer trial endpoints ( disease - free survival [ dfs ] and os ) .
prior to these trials there was substantial pre - clinical and clinical evidence that bisphosphonates had anti - osteoclastic actions and there was some limited pre - clinical evidence of direct cytotoxic anti - tumour effects .
importantly , there was also evidence in preclinical in - vitro and animal studies of the role of the vicious cycle in promoting bone metastasis growth , ; and it was known that tumour growth could be inhibited using bisphosphonates . not surprisingly , dfs benefits have been difficult to demonstrate in any single trial ( except abcsg-12 ) .
adjuvant clinical trials accrued breast cancer patients of all ages and these trials have not demonstrated clear benefits in the primary endpoints of dfs and os . however , protocol stipulated analysis by stratification arms in the three largest randomized trials ( post- and pre - menopausal in azure ; or age>50 versus < 50 in nsabp and royal marsden trials ) revealed a significant benefit for dfs / os in post - menopausal women ( azure ) and for bone metastasis - free interval and os in women > 50 ( nsabp and royal marsden ) .
many clinical scientists believe that a consistent observation like this across three large , well - conducted independent trials is a powerful observation .
furthermore , using traditional chemotherapy primary end - points such as dfs ( which includes second primaries , contra - lateral breast cancer and loco - regional recurrences ) for assessing a bone drug is likely to miss a valuable clinical effect .
an individual patient - level meta - analysis of all adjuvant bisphosphonate trials was proposed by the ebctcg and this study has now been published confirming the validity of the observation that bone - metastasis free survival and overall survival benefits occur in post - menopausal and older women receiving bisphosphonate therapy ( either oral clodronate or intravenous amino - bisphosphonates ) .
interactions between reproductive hormones , tumour and bone cell biology , and marrow stem cells evolve during the menopausal transition where estradiol and inhibin dominate in the pre - menopausal woman , and activin and the tgf - beta superfamily dominate as bone metabolism regulators in the post - menopausal woman .
prior to the bonus 2015 meeting a preliminary meeting was held in montreal in november of 2014 .
the working group felt that the development of specific research questions focused on
bone metastasis should be formulated from the starting point of unmet clinical needs . in particular , the following issues were felt to be of key importance : understanding the biology associated with the process of bone metastasis initiation and progression and developing potential treatment strategies to improve outcome of patients with bone metastases .
there was also a strong feeling that research initiatives should incorporate questions that cut across the cancer care continuum from basic biomedical research to clinical translation and patient outcomes .
based on the priorities discussed during the preliminary meeting , the following themes were selected for in - depth discussion at the 2015 bonus meeting : is bone metastases - related pain the main issue facing patients ? are there new therapeutic targets for patients with bone metastases ? how do we more firmly link basic science with clinical practice ?
each of these themes will be summarised below.theme 1 : is bone metastases - related pain the main issue facing patients ? : is bone metastases - related pain the main issue facing patients ? this session consisted of presentations about metastasis - related bone pain from the perspectives of patient experience and clinical care.what are the current limitations of bone - targeted agents in relation to bone pain in patients with bone metastases ? eitan amir , md what are the current limitations of bone - targeted agents in relation to bone pain in patients with bone metastases ?
eitan amir , md while any malignancy may metastasise to bone , it is most prevalent in advanced breast ( 7080% ) , prostate ( 7080% ) , thyroid ( 60% ) , lung ( 1050% ) and renal cancers ( 30% ) , , , , .
the consequences of bone metastases include reduced survival , morbidity and pain that negatively affect the patient 's quality of life ( qol ) as well as skeletal - related events ( sres ) , . despite the fact that randomized trials of bisphosphonates , and denosumab , have shown reduced incidence of sres , prolonged time to occurrence of sres and an improvement in pain control , clear improvements in overall quality of life ( qol )
two trials comparing pamidronate to placebo showed that patients in the pamidronate arms experienced less pain ; however , there was no difference in the overall qol .
similarly , in the randomized trial comparing denosumab to zoledronic acid , improvements in qol were observed in both arms with denosumab not showing consistently greater magnitude of improvement over the entire trial period .
whether qol improvements resulted from the administration of bone targeted therapy or the concurrent administration of systemic anti - cancer therapy is unclear especially as the placebo - controlled randomized trials of bisphosphonates did not show differences in qol between arms , given that bone - targeting agents have not been found to affect overall or progression - free survival and have known risks and adverse effects , including rare but severe toxicities such as hypocalcaemia and osteonecrosis of the jaw ( onj ) , , , this lack of improvement in qol is disappointing . as we have likely reached the limits of therapeutic osteoclast inhibition with bisphosphonates and denosumab
there is increasing interest in the effects of other anti - cancer agents on the bone .
for example , the use of new treatments for prostate cancer such as abiraterone acetate , enzalutamide and radium 223 have all shown decreased rates of sres as well as improvements in survival . as a result
, there is a need to develop better agents not only to reduce bone pain but to also identify strategies to optimise the use of bone - targeted agents as sres become less common .
as more effective cancer treatments become available , it will be important to further explore optimal dosing of bone - targeting agents in these patients.what do patients with bone metastases need ?
virginia jarvis , rn virginia jarvis , a nurse specialist in pain and palliative care , followed up with a discussion of known as well as poorly understood needs of patients with bone metastases in ambulatory and palliative care .
pain assessment for patients with bone metastasis presents unique problems as pain is often incidental in nature with high pain scores with movement and minimal to zero pain scores at rest making the standard 010 verbal scoring system an ineffective tool .
the brief pain inventory was discussed as a pain assessment instrument that could best inform health care professionals to the actual pain state and help guide the clinician to the choice of appropriate treatments that may include interventional therapies that go beyond the world health organisation analgesic ladder .
indeed , in a large recently presented study , risk of sres was correlated with worsening pain scores on the brief pain inventory .
the unmet needs of patients include treatments such as physiotherapy , occupational therapy and social work as pain effects mobility , activities of daily living , the ability to drive and financial decline .
following this presentation there was extensive discussion around whether bone pain was the major issue facing patients or reduced mobility .
this could be an important direction for future studies and requires further evaluation.what are orthopaedic surgeons doing in 2015 for patients with painful bone metastases ?
joel werier , md orthopaedic stabilisation of osseous metastatic lesions can provide rapid and effective pain relief in patients presenting with significant bone destruction and impending or pathologic fracture .
it is essential to develop a collaborative relationship between engaged orthopaedic surgeons and medical as well as radiation oncologists in order to facilitate multidisciplinary care of an individual patient .
a clear understanding of life expectancy , patient expectations , and tumour biology can help guide clinical and surgical decision making .
for example , orthopaedic interventions could be significantly altered if it was evident that a patient had a very short prognosis .
minimally invasive techniques such as radiofrequency ablation , percutaneous cryoplasty , cementoplasty , and vertebroplasty can be effective in patients who are poor surgical candidates or who have a specific lesion that can be addressed by these techniques .
surgical stabilization is almost always supplemented with radiation to minimise tumour progression and implant failure . a collaborative approach with orthopaedic surgical consideration
can greatly aid in the palliation , mobilisation , and quality of life of affected individuals .
basic and translational researchers should be invited to collaborate with clinicians caring for patients with metastatic bone disease .
for example is local delivery of biologics , incorportated into scaffods / cements used to stabilise surgical defects a useful approach ?
in addition , in our centre orthopaedic stabilization with tumour de - bulking is a unique opportunity to provide good quality tumour specimens for basic science and translational research investigating novel therapies.study endpoints in trials of bone - targeted agents and radiotherapy should bone pain be a criteria ? kris denis md and mark clemons , md
study endpoints in trials of bone - targeted agents and radiotherapy should bone pain be a criteria ? kris denis md and mark clemons , md traditionally , bisphosphonates have been evaluated in terms of sre prevention ; however , its definition has changed with time .
for example , while older studies included hypercalcaemia as an sre , most subsequent trials do not take it into account .
second , clinical trials often mandate bone surveys and isotope bone scans every 3 months , resulting in the detection of asymptomatic sres . including these asymptomatic events
as endpoints makes it challenging to determine whether newer agents actually represent an improvement in preventing what truly matters to patients : symptomatic sres , , .
another factor limiting the use of sres as a meaningful endpoint is that bone pain per se is not considered a sre despite the fact that clearly impacts patient qol and is tied to the use of radiotherapy .
indeed , the conditions under which radiotherapy has been indicated ( and recorded as a sre in previous trials ) are not standardized . indeed , a review of literature and survey on qol perception outcomes of radiation therapy for bone metastasis has shown that the impact of metastatic disease and radiotherapy extends beyond pain . looking beyond simple endpoint metrics , perhaps an alternative way to measure
the impact of bone metastases on patients is through a broader examination of qol impact .
the european organisation for research and treatment of cancer ( eortc ) quality of life group bone metastases module ( eortc qlq bm22 ) is a bone metastases- specific instrument that measures the impact of bone metastases on patients quality of life .
it has been extensively validated internationally and is well - suited to use within clinical trials .
conclusion 1 : given that pain / mobility remains a significant issue for many patients , the group felt the first priority for future studies should be to investigate the experience in patients with bone metastatic cancer with regard to pain , mobility , fatigue , psychological distress , reduced performance and treatment side - effects .
it will only be possible study the impact of all these issues in the individual patient with a dedicated bone metastasis health - related qol tool.theme 2are there new targets for patients with bone metastases ? are there new targets for patients with bone metastases ?
the second session involved presentations discussing the strategies and ideas in development of new treatment strategies for patients with bone metastases.better use of established agents ?
mark clemons , md better use of established agents ? mark clemons , md one of the ways to improve therapeutic outcomes would be to use current agents more effectively , .
given that patients with bone - only metastatic disease may experience longer term survival , and the risk of adverse events from bone - targeting agents increases with cumulative exposure , the question around optimal dose and dosing interval remains unanswered , , .
a survey of physicians who treat patients with bone metastases from breast cancer and metastatic castration - resistant prostate cancer showed significant variability in the use of bone - targeting agents , including the choice and dosing interval .
a systematic review evaluating de - escalated treatment ( i.e. every 12 weeks ) of breast cancer patients with bone - targeted agents in comparison to current standard practice of every 34 weeks showed a clear knowledge gap with regard to establishing the clinical benefits of de - escalated bone targeted agent therapy in metastatic breast cancer patients .
similarly , a recent systematic review also demonstrated that denosumab 12-weekly was as effective as 4-weekly dosing in patients with bone metastases from prostate cancer ( in press ) .
integration of these reduced frequencies of bone - targeted agents into routine clinical practice could benefit both patients ( reduced visits to the cancer centre for treatment and less drug toxicity ) and the health care system ( lower drug costs ) .
for many years it has been hoped that use of biochemical endpoints , such as bone resorption markers , may offer a solution to the challenge of using pain scores by offering a quantitative , rather than qualitative , assessment of bone - targeting agent effect on the bone in the presence of skeletal metastases .
retrospective analyses of bisphosphonate trials suggest that early normalisation ( at 3 months ) of urinary n - terminal telopeptide levels in patients undergoing treatment with bisphosphonates are associated with a significantly reduced risk of a first sre , first fracture , surgery to bone , or death . however , incorporation of these biomarkers of bone turnover , pain scores and sres to develop practical strategies to improve the care of patients has to date been extremely challenging , , .models for bone metastases christina addison , phd
models for bone metastases christina addison , phd there are a number of pre - clinical animal models to study cancer metastasis to bone . typically , approaches are employed that include syngeneic , transgenic and xenograft models of bone metastasis . experimentally , the most frequent route of injection of cancer cells is intracardiac ( into left cardiac ventricle ) , which permits seeding and colonisation of tumour cells in metaphyses of the long bones .
intratibial ( intraosseous ) injection of tumour cells directly into the marrow space is often used to examine tumour stromal interactions during the growth of bone metastatic lesions .
finally , vossicle models are emerging in which foetal human bone is implanted subcutaneously into mice , followed by intra - cardiac or local injection of human tumour cells that colonise the human bone fragments and form metastases .
histological and immunhistochemical techniques are employed to study excised tissues while increasingly , in vivo imaging modalities ( optical imaging systems ( ivis ) , radiography , ct and mri ) have been used to assess the growth of bone metastatic lesions and the effect on bone resorption / destruction .
while these models have been very useful in delineating mechanisms that drive the colonisation and growth of cancer cells in bone , they have not been interrogated sufficiently .
hopefully these models can be utilised further to identify novel therapeutic targets and develop more effective treatment combinations that could enhance overall survival.new targets john hilton , md
new targets john hilton , md a series of potential emerging agents may be helpful in addressing bone - only disease .
cabozantinib ( xl184 ) is an orally bioavailable tyrosine kinase inhibitor with potent activity against met and vegfr2 . in early clinical studies in patients with metastatic prostate cancer
, cabozantinib demonstrated significant and rapid effects on bone scan lesions as well as on markers of bone formation and resorption , bone pain and narcotic use .
in addition , statistically significant improvement in progression - free survival was seen with cabozantinib compared with placebo .
while the subsequent larger registration study was negative in terms of overall survival , it again showed important findings in metastatic bone disease , including resolutions of metastases in bone scans and reductions in bone turnover markers .
it is possible that the observed clinical effects on bone are related to decreased rankl expression in osteoblastic cells and inhibition of osteoclastogenesis and pthrp - stimulated bone resorption , thus providing a rationale for beneficial skeletal observations while failing to control progression of the malignancy .
it is also possible that cabozantinib should not be considered a bone - targeting agent per se , but as an effective anti - tumour agent given its efficacy in metastatic renal cell cancer . given the effects of cabozantinib on bone metastases in patients with castration resistant prostate cancer it would be interesting to see whether or not combinations with bisphosphonates or denosumab are synergistic or not.radium 223 as a novel therapeutic for bone metastases urban emmenegger , md radium 223 as a novel therapeutic for bone metastases urban emmenegger , md radium 223 is a calcium mimetic alpha emitter that selectively binds to areas of increased bone turnover such as bone metastases . in patients with castration - resistant prostate cancer , radium 223
qol was also seen to be better with radium 223 versus placebo . since radium 223 is the first bone - targeted agent with documented positive impact on overall survival . as with cabozantinib ,
mentioned above , it is also possible that as radium 223 delivers radiation to the bone metastases itself it should also be considered an anticancer agent and not just a bone - targeted agent .
results in other tumour types such as breast cancer are eagerly awaited.immune therapies for bone metastases guy ungerechts , md immune therapies for bone metastases guy ungerechts , md targeted infection of cancer using novel oncolytic viral therapies via binding of tumour - specific surface receptors is an exciting and promising field .
therapy combining oncolytic virus with an immune checkpoint blockade for immunovirotherapy can lead to an immunomodulation and ultimately disease response .
while immunomodulation may prove to be extremely important for effective tumour control in the bone microenvironment , tumour - specific receptors for bone metastatic lesions remain less well characterized.theme 2 conclusion : despite over two decades of widespread use of osteoclast - targeting agents such as bisphosphonates and more recently denosumab these have had no discernible effect on response rates , progression free or overall survival .
studies on dosing intervals with osteoclast - targeting agents continue to show that treatment can be safely de - escalated and studies are needed to explore their role in the presence of increasingly effective anti - cancer agents .
studies will need to integrate basic science models into clinical practice so that novel agents and their combinations can be more rapidly evaluated in the laboratory before performing large , expensive studies in patients.theme 3how do we more firmly link basic science with clinical practice ? : despite over two decades of widespread use of osteoclast - targeting agents such as bisphosphonates and more recently denosumab these have had no discernible effect on response rates , progression free or overall survival .
studies on dosing intervals with osteoclast - targeting agents continue to show that treatment can be safely de - escalated and studies are needed to explore their role in the presence of increasingly effective anti - cancer agents .
studies will need to integrate basic science models into clinical practice so that novel agents and their combinations can be more rapidly evaluated in the laboratory before performing large , expensive studies in patients . how do we more firmly link basic science with clinical practice ?
it is evident that there has to be meaningful collaboration between basic science and clinical practice . in the final session ,
bone metastasis models and their limitations were discussed . finally , clinicians presented information on future directions in the bone metastasis research field .
it was hoped that this would provide additional information for basic science collaboration.animal models for bone cancer - induced pain
svetlana v. komarova , phd one of the factors limiting research into the area of bone cancer - induced pain is the limited number of animal models where treatment hypotheses can be tested . dr komarova presented data on the behavioural pain phenotype in an experimental breast cancer bone metastasis model and on the pain - relieving effects of microenvironment - targeting adjuvant therapies . in a mouse model , where immunocompetent mice were injected intra - tibialy with murine mammary carcinoma cells or saline ,
breast cancer bone metastasis was associated with gradual development of osteolysis , spontaneous limping and guarding of affected limbs , as well as a significant increase in the sensitivity to mechanical , heat and cold stimuli .
moreover , unilateral breast cancer bone metastasis was found to drive hypersensitivity , bone remodelling and sensory neuronal plasticity at sites distant from the tumour area .
the anti - inflammatory and osteolysis - targeting drug rapamycin reduced hypersensitivity to mechanical and thermal stimuli in the cancer - bearing and contralateral limbs , while the osteoclast - targeting drug pamidronate reduced thermal sensitivity at the cancer - bearing and contralateral limbs .
thus , localised bone cancer drives osteolysis , sensory hypersensitivity , and neuroplasticity both locally and distantly from the primary lesion .
ultimately mechanistic based therapeutics is essential to develop novel agents for cancer induced bone pain .
unfortunately , despite the promise of these models , there are difficulties in translating these studies to patient experience .
first , while pain assessment in patients is generally done using validated questionnaires , such tools are not practical in animal studies .
in contrast , quantitative sensory tests which assess the sensitivity thresholds to mechanical and thermal stimuli can be used in humans and animals , and were shown to be informative and predictive in patients with neuropathic and musculoskeletal pain , , as well as chemotherapy - related pain in cancer patients , .
however , the validity of quantitative sensory tests in providing measurable pain information in bone metastasis patients has been only assessed in a small number of patients , making it impossible to translate pain - related conclusions obtained in animal studies to patient care .
in addition , the treatment protocol in experimental animals commonly does not reflect the usual treatment protocol in patients such as use of clinically relevant chemotherapy dosing schedules and time delay between initiation of bone metastasis and development of symptoms which will lead to treatment in patients .
thus , development of direct correlates between measures used to quantify the disease progression in animal models and in patients will help in knowledge translation from basic science studies to clinical care.challenges of ex - vivo models for identifying new targets christina addison , phd challenges of ex - vivo models for identifying new targets christina addison , phd a significant limitation of the use of cell lines in breast cancer bone metastasis related research has been the fact that so many cell lines are from hormone receptor negative lines , when the vast majority of patients have hormone receptor positive disease .
addison and her team have therefore established a programme in collaboration with orthopaedic surgeons to obtain tumour tissue straight from the operative room from patients undergoing surgery for bone metastases complications . as a result , it is possible to isolate new bone metastatic - derived cancer cell lines , to test drug combinations in ex vivo bone metastatic tumour tissues and to develop patient derived xenograft models .
there remain challenges in translating these models into the clinical practice , such as a need to improve quantitative assays for tumour burden and ultimately evaluate response to treatment in vivo and models that can better mimic to the human in vivo phenotype.bisphosphonates as adjuvant therapy for breast cancer and the relevance of the low estrogen environment alexander paterson , md bisphosphonates as adjuvant therapy for breast cancer and the relevance of the low estrogen environment alexander paterson , md since bisphosphonates were found to benefit patients with bone metastases from breast cancer , trials of adjuvant bisphosphonates in operable primary breast cancer were set up in the 1990s and early 2000s , some using end - points appropriate for a class of drugs whose dominant mode of action is in bone ( e.g. bone metastasis - free interval and overall survival [ os ] ) , and others , using traditional cancer trial endpoints ( disease - free survival [ dfs ] and os ) .
prior to these trials there was substantial pre - clinical and clinical evidence that bisphosphonates had anti - osteoclastic actions and there was some limited pre - clinical evidence of direct cytotoxic anti - tumour effects .
importantly , there was also evidence in preclinical in - vitro and animal studies of the role of the vicious cycle in promoting bone metastasis growth , ; and it was known that tumour growth could be inhibited using bisphosphonates . not surprisingly , dfs benefits have been difficult to demonstrate in any single trial ( except abcsg-12 ) .
adjuvant clinical trials accrued breast cancer patients of all ages and these trials have not demonstrated clear benefits in the primary endpoints of dfs and os .
however , protocol stipulated analysis by stratification arms in the three largest randomized trials ( post- and pre - menopausal in azure ; or age>50 versus < 50 in nsabp and royal marsden trials ) revealed a significant benefit for dfs / os in post - menopausal women ( azure ) and for bone metastasis - free interval and os in women > 50 ( nsabp and royal marsden ) .
many clinical scientists believe that a consistent observation like this across three large , well - conducted independent trials is a powerful observation .
furthermore , using traditional chemotherapy primary end - points such as dfs ( which includes second primaries , contra - lateral breast cancer and loco - regional recurrences ) for assessing a bone drug is likely to miss a valuable clinical effect .
an individual patient - level meta - analysis of all adjuvant bisphosphonate trials was proposed by the ebctcg and this study has now been published confirming the validity of the observation that bone - metastasis free survival and overall survival benefits occur in post - menopausal and older women receiving bisphosphonate therapy ( either oral clodronate or intravenous amino - bisphosphonates ) .
interactions between reproductive hormones , tumour and bone cell biology , and marrow stem cells evolve during the menopausal transition where estradiol and inhibin dominate in the pre - menopausal woman , and activin and the tgf - beta superfamily dominate as bone metabolism regulators in the post - menopausal woman .
bone oncology requires a multi - disciplinary team approach and a diverse arsenal of cancer therapeutics .
the bonus 2015 meeting was structured to identify unanswered research questions and unmet clinical needs that could form the basis for an integrated team grant application , with the goal of positively impacting the care of bone metastatic patients .
this review summarizes the bone oncology - related topics presented and discussed among the meeting attendees .
it is clear that many unsolved challenges and knowledge gaps currently exist that are barriers to effective treatment of metastatic bone disease , which represent opportunities for additional research by a multi - disciplinary team . | ### Summary:
: in an era of reduced peer - reviewed grant funding , performing academic bone oncology - related research has become increasingly challenging . over the last 10 years
we have held an annual meeting to bring together clinicians , clinician / scientists and basic biomedical researchers interested in the effects of cancer and its treatment on skeletal tissues . in the past
these bone and the oncologist new updates conference ( bonus ) meetings have served as critical catalyst for initiating productive research collaborations between attendees .
the 2015 bonus meeting format focused on potential key research themes that could form the basis of a coordinated national research strategy to tackle unmet clinical and research needs related to complications associated with cancer metastasis to bone .
the three themes planned for discussion were : is bone metastases - related pain the main issue facing patients ? are there new therapeutic targets for patients with bone metastases ? how do we more firmly link basic science with clinical practice ? we present a summary of lectures and commentaries from the attendees to serve as an example that other similarly motivated groups can model and share their experiences .
it is our hope that these presentations will result in comments , feedback and suggestions from all those researchers interested in this important area . |
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: information from space missions has provided
motivation for a wide
range of laboratory experiments and modeling calculations .
the results
of the cassini huygens mission to saturn and especially the
rich data on titan s atmosphere and surface from the huygens
probe and lander have turned considerable attention to studying the
ionosphere and atmosphere of this object .
the atmosphere of titan
is composed mostly of molecular nitrogen ( above 95% ) with 25%
of methane and small amounts of more complex hydrocarbons ( ethane ,
ethylene , acetylene , propane ) , traces of nitriles , and oxygen - containing
compounds .
the transmitted data revealed
a rich chemical composition of the ionosphere and led to emphasis of importance of nitrogen chemistry in the upper
atmosphere .
present data on gas phase processes relevant to the atmosphere
of titan are plentiful and have been summarized in several recent
reviews .
the direct observations of the satellite
revealed also the existence
of aerosols forming the organic haze in the atmosphere .
pyrolytic analysis suggested a chemical composition that includes
carbon , hydrogen , and nitrogen .
considerable
effort has been put into synthesizing the laboratory analogues of
these aerosols , referred to as tholins ,
but up to now the problem remains open .
however , the existence of
aerosols brought up the question of heterogeneous reactions of ions
and neutrals on their surface .
though information on reaction of ions
and neutrals in the gaseous phase , relevant to the atmosphere of titan ,
is plentiful , information on possible heterogeneous processes appears
to be very limited .
we report here on an observation of elementary
heterogeneous chemical
reactions of n2 and n ions with
surface hydrocarbons that lead to the formation of the hcn ion .
surface
interaction of slow ( up to 100 ev ) ar , n2 , and n ions with surfaces covered with adsorbed
hydrocarbons .
the principal aim of the studies was to provide data
on collisions of selected low - energy seeding gas ions ( argon and nitrogen )
with surfaces relevant to construction of fusion devices ( carbon ,
tungsten , beryllium ) .
our previous investigation of collisions
of molecular ions of energies
from several electronvolts up to about 100 ev with solid surfaces
has provided information on the neutralization ( or survival probability )
of ions , on dissociation processes and chemical reactions
at surfaces , on partitioning of energy in
these processes , and on the low - energy
sputtering of the surface material .
chemical reactions between low - energy incident ions and surface
material have been observed in many systems .
the reaction described
most often is hydrogen atom transfer between some incident ions ( e.g. ,
polyatomic organic cations ) and hydrogen - containing surface material , leading to protonated incident ions .
other reactions
( e.g. , formation of csco , csoh , xef , xecf , xecf2 ) have been
observed in specific systems .
collisions of molecular ions n2 with surfaces have been studied in particular in connection
with surface modification ( nitridation ) , scattering results concerned neutralization and dissociation at
higher incident energies .
to our knowledge ,
however , no chemical reactions of low - energy n2 or n ions at surfaces have been so far reported .
the observation of hcn formation in heterogeneous reactions
of the nitrogenous ions with surface hydrocarbons can be of interest
from the point of view both of chemical reactivity of nitrogenous
ions at surfaces and of astrophysics .
however , the relevance to the
conditions of space and planetary atmospheres ( titan ) should be regarded
with caution .
we believe that the formation of the molecular ion hcn in the observed heterogeneous processes is worth reporting ,
though the probability of the reactions is rather small . the reaction
of n has been observed clearly at all measured incident
energies
, it appears to be exothermic and thus it may be expected
to occur even at very low n energies relevant to space
conditions . on the other hand , the reaction of n2 seems to have a high activation barrier ( or endothermicity ) as inferred
from its observation only at incident energies of n2 above about 50 ev .
the occurrence of ions of such high energies
in planetary atmospheres is unlikely and this limits the relevance
of the n2 reaction to conditions of the astrophysical
systems .
the experiments were carried out
on the tandem apparatus bestof
in innsbruck , described in detail in our previous publications ( e.g. ,
ref ( 18 ) ) .
it consists
of two mass spectrometers arranged in tandem geometry ( figure 1 ) .
projectile ions were produced in a nier - type
ion source by electron ionization ( 75 ev energy ) of argon or nitrogen .
the ions produced were extracted from the ion source region and accelerated
to 3 kev for mass and energy analysis by the double - focusing two - sector - field
mass spectrometer . after passing the mass spectrometer exit slit ,
the ions were refocused by an einzel lens and decelerated to the required
incident energy , before interacting with the target surface .
the incident
impact angle of the projectile beam was kept at 45 and the scattering
angle was fixed at 46 ( with respect to the plane of the surface ) .
the energy spread of the projectile ion beam was about 0.5 ev ( full
width at half - maximum ) .
a fraction of the product ions formed at the
surface left the shielded chamber through a 1 mm diameter orifice .
the ions were then subjected to a pulsed deflection - and - acceleration
field that initiated the time - of - flight analysis of the ions .
the
second mass analyzer was a linear time - of - flight ( tof ) mass spectrometer
with a flight tube about 80 cm long .
the mass selected ions were detected
by a double - stage multichannel plate connected to a multichannel scaler
and a computer .
the product ion yields were obtained by integration
of the area under the recorded peaks in the mass spectra .
schematics
of the tandem apparatus bestof : a mass - selected ion
beam interacts with a surface , and product ions are detected by a
time - of - flight ( tof ) mass spectrometer .
the pressure in the ion source was ( 49 ) 10 mbar , the bakeable surface chamber and the tof analyzer
were maintained
under ultrahigh - vacuum conditions ( 10 mbar ) by
a turbo - pump
. however , even these ultrahigh - vacuum conditions did
not exclude deposition of a layer of hydrocarbons on the surface ,
kept at room temperature , whenever the valve between the sector - field
mass spectrometer and the surface chamber was opened and the pressure
in the surface region increased to the 3 10 mbar range . to investigate the dependence of product ion signals
on surface temperature , the surface samples could be heated during
measurements up to 450 c by a heating wire located inside the
surface sample holder .
the hydrocarbons adsorbed on the surface
of the solid samples are
generally assumed to be cracked pump oil aliphatic hydrocarbons of
chain length of about c8 .
the hydrocarbon
coverage at room temperature is quite stable and constantly renewable
by adsorption from the hydrocarbon background . at higher surface temperatures
it may be viewed as a surface covered largely or partially with islands
of hydrocarbons , which decrease in size with increasing temperature
of the sample . at 600 c
the surface is practically devoid of
any hydrocarbons , as checked by the absence of h - atom transfer reactions
with radical cations .
the metal
samples were cut from a 0.25 mm tungsten ( alfa aesar ,
# 10415 ) and beryllium ( alfa aesar , # 41642 ) foils , respectively .
the
carbon - fiber composite nb-31 ( cfc ) sample was obtained from the max - planck
institute for plasma chemistry , garching .
it is a carbon carbon
composite with interwoven carbon fibers densified by pyrocarbon .
ionization of n2 by electrons produces n2 ions in the ground state xg as well as in the au ,
bu , and cu electronic excited states .
the excited states
pass in fast radiative transitions to the ground state ( b , c ) , the
lifetime of the a - state is of the order of microseconds , short in comparison with the passage time of
the beam to the surface ( longer than about 5 10 s ) .
therefore , it is
generally assumed that the n2 ions in the beam
are practically only in their electronic ground state xg .
the beam of atomic ions n formed by electron dissociative
ionization of n2 is composed mostly of ions in the ground
state p , about 15% is expected to be in the long - lived
metastable excited state d. a small admixture of doubly charged ions n2 could be avoided by measuring at electron energies of 40 ev , below
the ionization energy of the dication .
as an example ,
figure 2 shows mass spectra of product ions
resulting from the interaction of ar with the tungsten
target kept at room temperature ( a ) , heated to 150 c ( b ) , and
heated to 300 c ( c ) .
the mass spectra were measured at a series
of incident energies of ar between 20 and 100 ev .
the ion yields are mutually
comparable , because they were normalized to the same projectile beam
intensity and measurement time .
mass spectra of product ions from collisions
of ar with
a hydrocarbon - covered tungsten surface kept at ( a ) room temperature
( rt ) , ( b ) 150 c , and ( c ) 300 c .
the spectrum of product ions at room temperature ( figure 2a ) showed mostly aliphatic hydrocarbon species sputtered
from the surface , covered by adsorbed hydrocarbons .
hydrocarbon ions
ch3 ( m / z 15 ) ,
c2h3 and c2h5 ( m / z 27 and 29 ) , c3hn ( m / z 3943 ) , and c4hn ( m / z 5357 ) , and to a lesser extent c5hn ( m / z 6569 ) , c6hn ( m / z 7781 ) , amd c7hn ( m / z 91 ) can be identified .
in addition to the hydrocarbon
ions , the spectra indicated the presence of surface contaminants :
water ( m / z 18 ) and traces of oxygen - containing
compounds from the sample cleaning procedure ( m / z 3032 , parts of ion yields at m / z 4245 and 5758 ) .
the spectrum
at the surface temperature of 150 c ( figure 2b ) showed a relative decrease of the hydrocarbon ion yields .
at the same time , alkali ions at m / z 23 ( na ) and m / z 39
and 41 ( k ) appeared in the spectrum .
the alkali ions are
regarded as sample contaminants whose conspicuous appearance in the
spectra was due to their easy and disproportionate ionization efficiency .
the mass spectrum at 300 c ( figure 2c ) was dominated by strong ion signals of these alkali ions .
aliphatic hydrocarbon ions were reduced even more , only the c2 group
at m / z 2729 ) was clearly
observable .
no sputtering of the basic material ( ions of tungsten
or its compounds ) was observed at these low incident energies in any
of the experiments .
figure 3 shows the
analogous mass spectra
from collisions of n2 projectiles with the
same tungsten surface , at the same incident energy of 70 ev , and at
the three surface temperatures .
much the same as what was said about
ar collisions holds for the n2 interaction :
at room temperature , sputtering of hydrocarbon ions of the groups
c1c7 of approximately comparable yields .
the yield of m / z 28 was higher ( surviving n2 projectile ions ) . at 150 c
the ion yields decreased
with one notable exception : the ion yield at m / z 27 dramatically increased in comparison with the ion yield
at m / z 29 .
alkali contaminants na and k appeared in the spectra , too . at 300 c
the yields of hydrocarbon ions decreased to very small values , whereas
the alkali contaminants increased even more .
most significantly , however ,
the ion yield of m / z 27 strongly
increased in comparison with the yield of other hydrocarbon product
ions .
mass spectra of product ions from collisions of n2 with a hydrocarbon - covered tungsten surface kept at ( a ) room
temperature ( rt ) , ( b ) 150 c , and ( c ) 300 c .
this strong increase of the ion
yield at m / z 27 was not observed
in the ar spectra , and
we interpret it as being due to the product of a surface reaction
of the projectile ion n2 with the surface hydrocarbons ,
namely formation of hcn in a heterogeneous ion
surface
chemical reaction of the type ( cnhm s denotes hydrocarbon
chain attached to the surface s)1correct assessment of the ion yield of m / z 27 due to hcn required
subtraction of the hydrocarbon background on m / z 27 .
the ion yields at m / z 27 and 29 in the mass spectra with ar originated only
from sputtered hydrocarbon fragments c2h3 and c2h5 and sputtering
of surface hydrocarbons with n2 may be regarded
as very similar to that by ar . to cross check this assumption ,
the ratio of yields of another pure hydrocarbon ion pair , m / z 53 ( c4h5 ) and m / z 55 ( c4h7 ) , was measured ( the yields at m / z 41 and 43 were obstructed by the signals of ar and k ions ) .
the ratio y(53)/y(55 ) was found to be practically the same for both ar and n2 collisions at all measured
incident energies and temperatures , thus justifying the above - mentioned
assumption . to subtract the hydrocarbon contribution , the mass
spectra with
ar and with n2
were mutually compared
at all incident energies and all sample temperatures measured , and
the ratio far = ( y / y)ar was determined from the ar mass spectra . the portion of the ion yield at m / z 27 in the mass spectra with n2 , corresponding to hydrocarbon sputtering , was then calculated
as ych , n2 = faryn2 , and subtracted from
the total ion yield at m / z 27 .
the
net yield at m / z 27 , ascribed to
the formation of hcn , was then y(hcn ) = y(27)n2 = y(27)n2 y(27)ch , n2 .
the value of far was found to increase
slowly at room temperature from about 1.1 to 1.4 for incident energies
20 100 ev , more steeply at higher surface temperatures ( at
300 c from 1.5 at 20 ev to 2.8 at 100 ev ) .
the net yield
ascribed to hcn formation in the n2tungsten surface collisions , y(27 ) ,
is plotted in figure 4 as
a function of the incident energy of n2 for
the three temperatures of the surface ( histograms ) , and ( for comparison )
the total yield of m / z 27 , y(27 ) , is plotted , too .
the error in determination was fairly
large , as indicated by the alternating positive and negative values
of y(27 ) at low incident energies ( in principle ,
y(27 ) should not be negative ) .
however , the
data clearly show a strong increase of y(27 )
at incident energies above about 50 ev . at 70100 ev the yield
ascribed to the reaction product hcn represents from 40%
( room temperature ) to 80% ( 300 c ) of the total ion yield at m / z 27
. net ion yield at m / z 27 , y , ascribed to the formation
of hcn ( histogram ) ,
and total ion yield at m / z 27 , y(27 ) ( points ) , from the interaction of n2 ions of incident energy einc with
a hydrocarbon - covered tungsten surface kept at room ( rt ) or elevated
( 150 c , 300 c ) temperature .
no indication of formation of n2h ( m / z 29 ) by h - atom transfer from surface
hydrocarbons could be discerned from the comparison of the ar and n2 mass spectra and from the analysis
of the ion yields at m / z 28 and
29 . if these considerations are correct , one should observe
the reaction
between n2 and surface hydrocarbons also in
experiments with other hydrocarbon - covered surfaces , though possibly
to a different extent .
figure 5 ( upper part )
shows the results of an analogous analysis of our experiments on ar and n2 collisions with hydrocarbon - covered
surfaces of carbon , namely of the carbon - fiber composite ( cfc ) surface ,
kept at room temperature and at 150 c .
the signals were much
weaker and the increase of the ion yield ascribed to hcn was much more buried in the hydrocarbon background ( about 20% of
the total yield of m / z 27 at room
temperature and 150 c ) but showed a noticeable increase above
about 5070 ev .
finally , figure 5 ( lower
part ) gives as an example of our analysis of the data from ar and n2 collisions with a hydrocarbon - covered
beryllium surface , the results of the measurements at 300 c .
the increase of the ion yield at m / z 27 due to the hcn formation shows up in the positive
value of y(27 ) at 70 ev ( 30% of the total
yield at m / z 27 ) .
in the measurements
with the room - temperature be surface and the surface heated to 150
c the y(27 ) signals were obstructed
by high hydrocarbon background , the values oscillated between small
positive and negative values and though they showed a tendency to
go up to positive with increasing energy they remained below the error
limits , and thus the identification was inconclusive .
therefore , the
data are not shown in the figure . different efficiency of forming
the ion product of reaction 1 on different surfaces ,
in comparison with the sputtered hydrocarbon background , is presumably
due to the differences in binding of surface hydrocarbons to the underlying
surface and/or to different efficiency of sputtering from the surfaces . net ion
yield at m
/ z 27 , y , ascribed to the formation of hcn ( histogram ) ,
and total ion yield at m / z 27 , y(27 ) ( points ) , from the interaction of n2 ions of incident energy einc with
a hydrocarbon - covered carbon - fiber composite ( cfc ) surface kept at
room ( rt ) or elevated ( 150 c ) temperature ( upper and middle
part ) ; analogous data for interaction of n2 ions with a hydrocarbon - covered surface of beryllium at 300 c
( lower part ) .
the data presented in
figures 25 led
us to the conclusion that in collisions of
n2 with hydrocarbons adsorbed on surfaces ,
hcn was formed in a heterogeneous reaction of the type
of reaction 1 at incident projectile energies
above 50 ev .
the experimental evidence came from the observation of
an increase of the ion yield at m / z 27 with the n2 projectile , in comparison
with the data using ar as the projectile , on three different
hydrocarbon - covered surfaces ( clearly on the w surface , partially
on carbon and be surfaces ) and its dependence on the incident energy
of the projectile ion and the surface temperature . in this connection
,
some further considerations may be useful . in the gaseous phase , hcn formation in reactions of
n2 with
hydrocarbons
was observed only as a minor channel ( 3% ) in the reaction
with acetylene in icr experiments .
product ions were only molecular
and fragment hydrocarbon ions formed in charge transfer and dissociative
charge transfer processes .
interestingly ,
energy calculations show that , starting
with ethane , reactions of n2 with alkanes ,
leading to hcn and neutral amines , are only slightly endothermic
and with the increasing chain length become thermoneutral and slightly
exothermic ; e.g. , the reaction2is exothermic
in the gaseous phase by about
5 kj / mol .
data in figures 4 and 5 indicate that the formation of hcn increased
significantly at incident energies of the n2 projectile above about 50 ev .
this behavior suggests either that
the reaction between n2 and surface hydrocarbons
in which hcn is formed is strongly endothermic or that
it has an activation barrier .
it follows from studies of surface scattering
of small polyatomic ions and partitioning of incident energy at surfaces and from theoretical model calculations that less than 10% of the incident energy , usually about 68% ,
is transformed into internal energy of the projectile in the surface
collision .
if this finding is applied to the molecular n2 projectile , the roughly estimated height of the putative
activation barrier ( or the endothermicity of the reaction ) would be
about 33.5 ev .
an activation barrier that high may be connected
with breaking the very strong n
the nature
of the neutral reaction products of reaction 1 is not known and this prevents any conclusions concerning the endothermicity
or activation barrier of the reaction .
however , embedding the other
nitrogen atom into the surface and formation of nitrogen - containing
surface compounds from surface hydrocarbons appears to be an interesting
possibility .
the probability
of reaction 1 is difficult to estimate , because
the area ( concentration )
occupied by hydrocarbons on the surface is not known .
however , from
the ion yields in the mass spectra , one may approximately estimate
that the reaction probability is of the same order of magnitude as
the survival probability of n2 ions , sa , in collisions with the hydrocarbon - covered
surfaces . more specifically , on the tungsten surface the ratio y(hcn ) to sa(n2 ) was 1:5 , 2:3 , and 1:1 at 70 ev and room temperature ,
150 c , and 300 c , respectively .
the survival probability , sa(% ) , the percent ratio of the sum of the intensities
of product ions to the intensity of the incident projectile beam ,
measured for n2 on hydrocarbon - covered tungsten and beryllium surfaces
led to the values of 0.0015 and 0.018 , respectively .
obviously , the
main process in the interaction of n2 with
the surfaces is neutralization of the projectile ions ( at least formally
analogous to electron transfer in the gaseous phase ) .
the formation
of the reaction product hcn should thus very approximately
occur in about one in 10 collisions of n2 with the surface .
figure 6 gives , as an example , the
mass spectra of product ions from
interaction of the atomic ion n with hydrocarbon - covered
tungsten surfaces at room temperature and heated to 150 c , and
incident energy of 70 ev . the product ions and their relative ratios
were very similar to those obtained in collisions of ar and n2 with tungsten , as discussed in the
previous paragraph , namely at room - temperature hydrocarbon ion groups
c1c5 , and to a lesser extent c6 and c7 .
the signal at m / z 14 corresponded to surviving n , the signals of contaminants from the cleaning procedure
( m / z 3032 and 45 ) and alkali
ions were very small . at 150
c only hydrocarbon ion groups c1c4
and alkali ions na and k could be indentified .
a substantial increase of the yield at m / z 27 ( arrows in figure 6 ) was clearly
observable .
the net yield at this m / z ascribed to the formation of hcn was estimated in the
same way as described in the previous paragraph and the results are
summarized in figure 7 .
the dependence of y(27 ) on the incident energy of n was entirely
different from that one for n2 collisions .
it showed positive values over all incident energies that peaked at
70 ev ( room temperature ) or 30 ev ( 150 c ) .
though for technical
reasons values below 20 ev could not be measured , it can be expected
that the decreasing part of the dependence would extend down to zero .
examples
of mass spectra of product ions from collisions of n ions
with a hydrocarbon - covered tungsten surface kept at
room temperature ( rt ) and 150 c .
the position of m / z 27 is denoted by an arrow . net ion yield at m
/ z 27 , y , ascribed to the formation of hcn ( histogram ) ,
and total ion yield at m / z 27 , y(27 ) ( points ) , from the interaction of n ions
of incident energy einc with a hydrocarbon - covered
tungsten surface kept at room ( rt ) and elevated ( 150 c ) temperature .
similarly as with n2 experiments , formation
of hcn in reactions with surface hydrocarbons was confirmed
by experiments on hydrocarbon - covered surface of carbon , a room - temperature
and heated surface of carbon - fiber composite ( cfc ) .
the formation
of hcn was clearly observable even with the room - temperature
surface over all incident energies of n ( figure 8) .
the yields of hcn represented 3070%
of the total yield at m / z 27 and
thus the result was much more convincing than in the case of the reaction
after n2 impact .
the shape of the dependence
hcn yield vs incident energy of n has to be
regarded as very approximate and a discussion of it was deliberately
avoided .
more precise data from a series of repeated measurements
are necessary to determine it .
net ion yield at m / z 27 , y , ascribed to the formation
of hcn ( histogram ) ,
and total ion yield at m / z 27 , y(27 ) ( points ) , from the interaction of n ions
of incident energy einc with a hydrocarbon - covered
surface of carbon - fiber composite ( cfc ) kept at room ( rt ) and elevated
( 150 c ) temperature .
it can be concluded from these observations that in collisions
of n with surface hydrocarbons , hcn is formed
in a heterogeneous reaction , probably with terminal ch3 groups of the adsorbed hydrocarbons , of the type3reaction 3 could be
clearly observed at all incident energies of n , down to
20 ev .
formation of protonated hydrogen cyanide , hcnh ( m / z 28 ) , could not be convincingly
identified
in the mass spectra .
reactions
of n with
lower hydrocarbons in the gaseous phase giving hcn are
exothermic and hcn represents about 10% of the products
with ch4 , c2h2 , and c2h4 .
the fraction of the protonated
product , hcnh , is even somewhat higher forming 32% with
ch4 and 15% of the products with c2h4 . starting with c3h8 ,
only hydrocarbon product
ions are formed in charge transfer and dissociative charge transfer
reactions .
however , energy calculations show that reactions with higher alkanes in the gaseous phase are
exothermic . with octane ,
e.g. , two reactions are possible4aor4bgiving as the neutral product either a pair
hydrogen molecule
the reaction exothermicities are fairly high , 201 kj / mol for reaction 4a and 188 kj / mol for reaction 4b .
therefore , we may assume that analogous reactions with alkyl chains
bound to the surface , presumably with the terminal ch3 groups ,
are likely to be exothermic , too , and to proceed readily even at low
energies of n ions .
similarly as with n2 , the signals corresponding
to the yields of hcn in the mass spectra are comparable
to the total yield of
product ions .
the survival probability sa(n ) on room - temperature tungsten surfaces , as estimated
from the correlation between sa and ionization
energy , should be about 0.005 .
this leads
to similar values of the reaction probability of the heterogeneous
reactions n surface hydrocarbons as for the reaction
with n2 , i.e. , of the order of about one in
10 collisions of the n ion with the surface ,
the main process at the surface being incident ion neutralization .
a significant increase of the ion yield
at m / z 27 in collisions of n2 and n ions with surfaces covered
by adsorbed hydrocarbons , not
observed in analogous collisions of ar ions , was ascribed
to heterogeneous reaction between n2 or n and surface hydrocarbons leading to hcn formation . in the case of n ,
the formation of hcn was
clearly observed , after subtraction of the hydrocarbon background ,
on hydrocarbon - covered surfaces of tungsten and carbon ( cfc ) at room
and elevated ( 150 c ) surface temperatures for all incident energies
between 20 and 100 ev , implying that the reaction is likely to occur
even at very small energies of the n ions . in the
case of n2 ,
the formation of hcn was observed on hydrocarbon - covered surfaces of tungsten
at all surface temperatures ( room temperature , 150 c , and 300
c ) and on surfaces of carbon and beryllium at some surface temperatures ,
in all cases the signal increased above background at incident energies
above about 50 ev .
this suggested endothermicity or an activation
barrier of the heterogeneous reaction of about 33.5 ev .
the
main process in the interaction of n2 or n with hydrocarbons on the surfaces is incident ion neutralization ;
with both nitrogenous ions the formation of hcn may be
very approximately estimated to occur in about one in 10 surface collisions . among the scarce information on heterogeneous
processes relevant
to planetary atmospheres
, the formation of hcn in reactions
of n and n2 and surface hydrocarbons
appears to be the first description of such heterogeneous processes
with nitrogenous ions .
however , the estimation of a possible relevance
of the reactions to astrophysical systems requires caution .
the reaction
of n with surface hydrocarbons is very probably exothermic
and likely to occur even with ions of very small energies relevant
to the conditions in interstellar space and nitrogen - containing planetary
atmospheres ( e.g. , titan ) . on the other hand , the reaction with n2 appears to have a high activation barrier ( or
an endothermicity ) estimated to about 33.5 ev and thus takes
place only with rather energetic ions ( above 50 ev ) whose presence
in the astrophysical systems mentioned above is unlikely . | ### Summary:
: a significant
increase of the ion yield at m / z 27 in collisions of low - energy ions of n2 + and n+ with hydrocarbon - covered room - temperature
or heated surfaces of tungsten , carbon - fiber composite , and beryllium ,
not observed in analogous collisions of ar+ , is ascribed
to the formation of hcn+ in heterogeneous reactions between
n2 + or n+ and surface hydrocarbons .
the formation of hcn+ in the reaction with n+ indicated an exothermic reaction with no activation barrier , likely
to occur even at very low collision energies . in the reaction with
n2 + ,
the formation of hcn+ was observed
to a different degree on these room - temperature and heated ( 150 and
300 c ) surfaces at incident energies above about 50 ev .
this
finding suggested an activation barrier or reaction endothermicity
of the heterogeneous reaction of about 33.5 ev .
the main process
in n2 + or n+ interaction with the
surfaces is ion neutralization ; the probability of forming the reaction
product hcn+ was very roughly estimated for both n2 + and n+ ions to about one in 104 collisions with the surfaces . |
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: adult obesity rates have increased dramatically in the united states , with the prevalence having risen more than twofold during the past 35 years
. marked increases in obesity prevalence have occurred among both males and females and across all racial / ethnic and socioeconomic groups [ 13 ] .
due to high prevalence , a rapidly increasing trend , large racial / ethnic and socioeconomic disparities , and an unfavorable international ranking , current obesity levels in both children and adults are seen as a major public health problem in the usa [ 15 ] . while trend and current data on obesity for us adults are routinely available for such major racial / ethnic groups as the whites , the blacks , and the hispanics [ 1 , 6 ] , prevalence estimates for specific asian / pacific islander ( api ) subgroups are less well analyzed , particularly temporal obesity patterns among them .
only a few studies have examined obesity differentials among apis at the national level [ 2 , 710 ] , and obesity trends , focusing on api subgroups , remain unexplored . the national health and nutrition examination survey ( nhanes ) , the primary source for measured height , weight , and obesity statistics in the usa , does not even identify the overall api group let alone report data for specific api groups [ 2 , 11 ] .
the statistics for apis are often presented under the residual category of all other races .
the api population , which comprises nearly 6% of the total us population , increased fivefold between 1980 and 2011 [ 1216 ] .
indeed , the major api groups such as the asian indians , the chinese , the filipinos , the koreans , and the vietnamese are among the fastest growing racial / ethnic groups in the usa [ 1216 ] . increases in immigration from asia following changes in the immigration act in 1965 have accounted for most of the rise in the api population [ 2 , 12 , 14 , 17 , 18 ] .
more than 28% of the 40.4 million immigrants living in the usa in 2011 came from asia [ 13 , 19 ] .
while immigrants account for 13% of the total usa population , they account for two - thirds of the api population [ 13 , 19 ] .
given the unprecedented population increase , analysis of obesity patterns among immigrants of various asian / pacific islander ethnicities assumes a special importance [ 2 , 9 ] .
monitoring health inequalities according to race / ethnicity , immigrant status , and socioeconomic status ( ses ) has long represented an important area of research and policy analysis in the usa [ 1 , 2 , 9 , 2024 ] . despite marked improvements in overall health and life expectancy ,
health inequalities in the usa have not only remained substantial but have also increased over time [ 9 , 2123 ] .
inequalities in chronic disease risks such as obesity , smoking , physical inactivity , and poor diet have contributed greatly to the persistence and/or widening of the health gradients [ 1 , 2 , 2123 ] .
the purpose of this study was to examine trends in obesity and overweight prevalence and body mass index ( bmi ) among major api subgroups and to identify those subgroups who are at high risk of obesity and who have experienced substantial increases in their obesity rates .
specifically , we ( 1 ) estimate changes in obesity and overweight prevalence over time among major api subgroups using large , nationally representative samples of us adults and ( 2 ) examine the extent to which obesity and overweight prevalence and bmi vary among specific api subgroups and how their obesity risks compare with those for the non - hispanic white population . since immigration is a major characteristic of the api population , our analysis is also stratified by nativity status to highlight immigrant differences in obesity rates within each group and across asian - american ethnicities .
temporal individual - level data on obesity , overweight , bmi , and selected socioeconomic , demographic , and behavioral characteristics were derived from the 19922011 national health interview surveys ( nhis ) [ 25 , 26 ] .
descriptive sociodemographic data for various racial / ethnic groups were also derived from the 2011 american community survey ( acs ) .
the nhis , which is conducted by the national center for health statistics , uses a complex , multistage probability design and is representative of the civilian noninstitutionalized population of the usa [ 1 , 2 , 9 , 25 , 26 ] .
all data are based on self - reports , including height and weight information , and obtained via in - home personal interviews [ 1 , 25 , 26 ] .
substantive and methodological details of the nhis are described elsewhere [ 1 , 25 , 26 ] .
annual trends in obesity and overweight prevalence and bmi were estimated for the overall api category , non - hispanic whites , and for all us adults from 1992 to 2011 . to analyze trends over time for specific api subgroups
, we pooled 4 years of the nhis data from 1992 to 1995 and 6 years of data from 2006 to 2011 .
aggregating data for several years in this fashion ensured sufficient sample sizes for analyzing patterns for groups stratified by asian ethnicity , immigrant status , and ses .
obesity and overweight differentials were analyzed for 242,523 api and non - hispanic white adults during 19921995 and 151,013 api and non - hispanic white adults aged 18 during 20062011 for whom information on bmi was available .
adult overweight was defined as a bmi 25 kg / m and obesity as a bmi 30
race / ethnicity was classified into 9 major categories : the non - hispanic whites , the chinese , the asian indians , the filipinos , the japanese , the koreans , the vietnamese , the hawaiians / pacific islanders , and a residual category of all other asian / pacific islanders . during 20062011
, data were not available separately for the japanese , the koreans , and the vietnamese and were included in the residual other api group .
three ethnic - minority groups : blacks , american indians / alaska natives , and hispanics were not considered .
immigrant status was defined on the basis of adults ' place of birth [ 2 , 9 , 10 , 20 ] .
us - born individuals were those born in one of the 50 states or washington , dc .
immigrants or foreign - born people refer to those born outside these territories [ 2 , 9 , 10 , 20 ] .
the joint variable of ethnic - immigrant status included 12 categories , with each racial / ethnic group divided into the us - born and foreign - born people .
note that , although the hawaiians are native - born , a small percentage of the hawaiian / pacific islanders are foreign - born or born outside the 50 states and washington , dc .
the pacific islander immigrants consist of people born in samoa , guam , and other pacific islands [ 16 , 18 , 19 ] .
in addition to race / ethnicity and immigrant status , we considered the following sociodemographic factors that are known to influence obesity : age , gender , marital status , region of residence , educational attainment ( 08 , 911 , 12 , 1315 , and 16 years of school completed ) , family income / poverty status , and physical activity ( pa ) [ 2 , 3 , 9 , 10 , 27 ] . these covariates were measured as shown in tables 13 .
annual family income was also measured as a categorical variable ; the income strata for 19921995 were < $ 7,000 , 7,00014,999 , 15,00019,999 , 20,00024,999 , 25,00034,999 , 35,00049,999 , and $50,000 .
pa level was measured by the number of times / week of vigorous activities of at least 10 minutes that caused heavy sweating or large increases in breathing or heart rate .
the variable was coded as < 1 , 1 - 2 , 3 - 4 , and 5 times / week of activity .
prevalence of regular pa was defined for adults who engaged in at least 3 sessions per week of vigorous leisure - time physical activity lasting at least 20 minutes in duration or at least 5 sessions per week of light or moderate leisure - time physical activity lasting at least 30 minutes in duration .
multivariate logistic regression was used to examine the association between the binary outcomes of obesity and overweight and selected socioeconomic and demographic factors .
least squares regression was used to model mean bmi . to account for the complex sample design of the nhis , sudaan software was used to conduct all statistical analyses .
the two - sample t - test was used to test the difference in prevalence between any two groups at one point in time or to test for changes in prevalence between two time points for a specific group .
log - linear regression models were used to estimate annual rates of increase in obesity / overweight trends in apis , non - hispanic whites , and the total us population [ 21 , 22 ] .
specifically , the logarithm of the obesity and overweight rates was modeled as a linear function of time ( calendar year ) , which yielded annual exponential rates of increase in prevalence [ 2 , 21 , 22 ] .
the obesity prevalence for the total us adult population aged 18 doubled from 14.2% in 1992 to 28.3% in 2011 .
the overweight prevalence for all us adults increased from 46.3% in 1992 to 62.8% in 2011 .
obesity prevalence among api adults tripled from 3.7% in 1992 to 13.3% in 2010 , whereas overweight prevalence for api adults doubled from 23.2% to 43.1% .
the obesity prevalence for the non - hispanic white adults increased consistently from 13.3% in 1992 to 26.9% in 2011 , whereas overweight prevalence for them increased from 45.2% to 61.4% during the same time period ( figure 1 ) . during 19922011 ,
ci = 3.54.45 ) for the non - hispanic whites , and 3.9% ( 95%
the annual rates of increase in overweight prevalence were 3.3% ( 95% ci = 2.93.6 ) for apis , 1.7% ( 95% ci = 1.41.9 ) for the non - hispanic whites , and 1.7% ( 95% ci = 1.41.9 ) for all us adults .
thus , although obesity and overweight prevalence was substantially lower for apis than for whites and the total population , the prevalence increased at a faster rate among apis .
the mean bmi for apis increased from 22.9 in 1992 to 24.8 in 2011 , while for the non - hispanic whites it increased from 25.2 to 27.4 ( data not shown ) .
more than 18% of hawaiians / pacific islanders were below the poverty line , compared with 13.7% of the vietnamese , 12.2% of the koreans , and 4.7% of the filipinos .
approximately 15% of the hawaiians / pacific islanders and 25.4% of the vietnamese were college graduates , compared with 71.1% of the asian indians .
approximately 24% of the hawaiians / pacific islanders and 30% of the vietnamese were employed in professional and managerial occupations , compared with 67% of the asian indians .
median family income varied from a low of 54,485 for hawaiians / pacific islanders to a high of 102,894 for the asian indians .
more than two - thirds of the asian indian , chinese , filipino , korean , and vietnamese populations were foreign born .
nearly half of all the vietnamese , the chinese , and the koreans were unable to speak english well , compared with 23% of the asian indians and filipinos .
table 1 shows significant increases in obesity and overweight prevalence between 19921995 and 20062011 for api subgroups , non - hispanic whites , and the total population . between 1992 and 2011 ,
obesity prevalence doubled for the chinese , the asian indians , the japanese , and the hawaiians / pacific islanders and more than tripled for the filipinos .
overweight prevalence increased by 84% for the filipinos and by 92% for the vietnamese .
in addition , considerable disparities in obesity and overweight prevalence among api subgroups and the non - hispanic whites can be seen in table 1 . in 20062011 ,
obesity prevalence varied from 4.4% for the chinese to 10.4% for the asian indians , 16.5% for the filipinos , and 39.6% for the hawaiians / pacific islanders .
the 20042006 data show an obesity prevalence of 8.7% for the japanese and 5.3% for the vietnamese .
the 20062011 overweight prevalence was highest for the hawaiians / pacific islanders ( 73.8% ) , followed by the non - hispanic whites ( 60.8% ) , the filipinos ( 53.2% ) , the asian indians ( 44.4% ) , the japanese ( 34.6% ) , the koreans ( 30.1% ) , and the chinese ( 27.9% ) .
regarding differences in obesity - related risk factors , the chinese , the asian indians , the filipinos , and the apis as a whole were more likely to be physically inactive than the non - hispanic whites . in terms of diet , substantial ethnic differences are noted , with the asian indians and the chinese being significantly more likely to consume fruits and vegetables 1 times / day than non - hispanic whites and the total population .
dietary information was not available for the koreans , the japanese , and the vietnamese . in 20062011 , after adjusting for sociodemographic factors , the asian indians , the filipino , the hawaiians / pacific islanders , the non - hispanic whites had , respectively 3.1 , 3.8 , 10.9 , and 4.7 times higher odds of obesity than those of their chinese counterparts . in 19921995 ,
ethnic differentials in obesity were similar , with data for additional groups showing 67% lower odds of obesity among the vietnamese and 89% higher odds of obesity among the japanese compared to the chinese .
risks of obesity and overweight increased with increasing duration in the united states ( tables 2 and 3 ) .
the obesity gradients by length of immigration were steeper in 20062011 than in 19921995 . compared with the us - born group , immigrants who had lived in the us for < 1 year or 15 years had 66% or 26% lower odds of obesity in 20062011 and 49% or 26% lower odds of obesity in 19921995 , respectively ( table 1 ) .
immigrants who had lived in the us for < 1 year or 15 years had 51% or 19% lower odds of overweight than the us - born group in 20062011 ( table 3 ) . in 20062011 , obesity prevalence ranged from 3.3% for chinese immigrants to 22.3% for the us - born filipinos , 26.4% for the us - born whites , and 41.1% for the native hawaiians / pacific islanders ( table 4 ) .
the overweight prevalence in 20062011 ranged from 25.2% for the chinese immigrants to 57.6% for the us - born filipinos , 61.1% for the us - born whites , and
mean bmi varied from a low of 23.1 for the chinese immigrants to a high for 29.8 for the native hawaiians and 30.1 for the pacific islander immigrants ( table 4 ) .
ethnic - immigrant differentials in obesity risks were greater than disparities shown by race / ethnicity alone ( table 4 ) . compared with chinese immigrants , the adjusted odds of obesity were 3.5 to 4.6 times higher for the us - born chinese and the foreign - born filipinos , 8.8 to 9.5 times higher for the us - born filipinos and the us - born whites , and 3.8 to 5.5 times higher for the us - born and the foreign - born asian indians . compared with the chinese immigrants , the odds of overweight were 2.4 times higher for the us - born chinese , 4.7 times higher for the us - born filipinos , 3.2 times higher for filipino immigrants , 2.4 to 2.7 times higher for the us - born and foreign - born asian indians , and 3.6 to 4.5 times higher for white immigrants and natives ( table 3 ) .
socioeconomic gradients in obesity were steep , with education and income levels contributing independently to obesity and overweight risks during both 19921995 and 20062011 ( tables 2 and 3 ) .
during 20062011 , those with less than a college education had at least 55% higher adjusted odds of obesity and at least 35% higher odds of overweight than those with a college degree . during 20062011 , adults living below the poverty line had 32% higher adjusted odds of obesity than those with family incomes at 500% of the poverty threshold
. marked socioeconomic gradients in obesity and overweight prevalence were generally found for all racial / ethnic groups ( table 5 ) .
obesity prevalence ranged from 4.3% for the chinese in the highest ses category to 29.2% for the low - ses filipinos , 32.5% for the low - ses whites , and 38.5% for the middle - ses hawaiians / pacific islanders .
the high - ses chinese had the lowest overweight prevalence of 24.4% and the low - ses asian indians , filipinos , and hawaiians / pacific islanders had the highest overweight prevalence of 62.9% , 63.6% , and 73.6% , respectively . compared with the high - ses chinese ,
the adjusted odds of obesity were , respectively , 8.8 and 14.7 times higher for the low - ses and middle - ses hawaiians / pacific islanders , 12.4 times higher for the low - ses filipinos , and 8.2 times higher for the low - ses whites .
the low - ses asian indians , filipinos , and hawaiians / pacific islanders had 5.7 , 8.6 , and 13.3 times higher odds of overweight than high - ses chinese , respectively ( table 5 ) .
after adjusting for race / ethnicity and socioeconomic factors , physical inactivity was associated with 54% higher odds of obesity ( or = 1.54 ; 95% ci = 1.461.62 ) and 36% higher odds of overweight ( or = 1.36 ; 95% ci = 1.301.42 ) during 20062011 ( data from the full models not shown ) .
with obesity prevalence continuing to rise rapidly , it is important to analyze trends in obesity and related risk factors among the asian / pacific islander americans who constitute a significant part of the contemporary us work force and who account for more than 40% of all new immigrants arriving in the usa since 2008 [ 13 , 19 ] .
obesity prevalence among all major api groups has increased sharply during the past two decades .
these increases appear to be more marked than those observed in the other major racial / ethnic groups in the us such as the whites , blacks , american indians / alaska natives , and mexican americans .
the high obesity levels in the hawaiians / pacific islanders and the alarming rise in obesity among the filipinos and the asian indians are of particular concern .
approximately 40% of the hawaiian / pacific islander adults are obese and 74% of them are either obese or overweight .
the rates for the hawaiian / pacific islanders are similar to those for the blacks and the american indians / alaska natives who have an obesity prevalence of 40% and whose overweight prevalence exceeds 70% [ 1 , 2 , 26 ] .
the mexican - americans and the puerto ricans are the two other us groups with relatively high obesity and overweight prevalence [ 2 , 26 ] . although recent trends indicate a slight decrease or leveling off in obesity / overweight prevalence among the apis as a whole between 2009 and 2011 , the absolute numbers of obese and overweight apis keep rising . in 2011 , there were an estimated 1.3 million obese and 5.0 million overweight api adults , compared to 0.2 million obese and 1.3 million overweight api adults in 1992 .
if the obesity trends of the past 20 years were to continue , our log - linear regression models forecast the obesity and overweight prevalence among api adults to increase to 22.0% and 60.1% , respectively , by 2020 . for the total us adult population ,
the obesity and overweight prevalence in 2020 are projected to reach 43.2% and 76.6% , respectively ( complete forecast data available from the authors ) .
as immigration to the us from asia , especially from china , india , south korea , and the philippines , continues to increase in the future , the racial / ethnic and demographic composition of the us population is expected to become even more diverse , and routine monitoring of obesity and related risks among the apis becomes increasingly important .
lower rates of obesity and overweight among the chinese , the asian indians , the filipinos , the japanese , the koreans , and the vietnamese , compared to the whites and other ethnic groups , are consistent with their lower rates of morbidity and mortality from obesity - related diseases and chronic conditions [ 7 , 9 , 20 ] .
prevalences of heart disease , diabetes , and hypertension are higher in the filipinos and asian indians than the chinese and the koreans .
the native hawaiians / pacific islanders , in fact , are more likely to suffer from heart disease , hypertension , stroke , and diabetes than any other racial / ethnic group in the united states [ 25 , 29 ] .
life expectancy is higher and rates of mortality from cardiovascular diseases , colorectal cancer , and diabetes are considerably lower among the asian - americans as a whole and among the chinese , the japanese , and the filipinos [ 9 , 10 , 20 ] . rising prevalence of obesity among the apis and whites is also consistent with the increasing trends in mortality and morbidity from diabetes seen among these groups and in the total us population [ 1 , 9 ] .
substantial immigrant differentials in obesity risks among the asian americans shown here are consistent with those reported for nativity differentials for the total population and for various racial / ethnic groups [ 2 , 810 , 30 ] .
positive immigrant selectivity in health , education , and skills has been suggested as a possible explanation for lower obesity risks among immigrants [ 2 , 9 , 10 ] .
positive selection may also apply for asian immigrants , who immigrate to the usa primarily under the skill criteria with high socioeconomic attainment levels [ 2 , 9 , 12 , 19 ] . as shown here and previously ,
obesity and other health advantages for immigrants tend to diminish with increasing acculturation levels or length of residence in the usa [ 2 , 810 , 20 , 30 ] .
the lower obesity risks among the us - born chinese and asian indians compared to us - born whites suggest that health advantages for certain asian - american groups may persist into the second generation and beyond [ 2 , 9 , 20 ] .
although genetic factors may account for some of the racial / ethnic differences in obesity , the lower obesity rates of immigrants in most ethnic groups as compared with their us - born counterparts indicate the significance of social environments , acculturation , and lifestyle factors [ 2 , 9 , 20 ] .
declining physical activity levels , increasingly sedentary lifestyles , and increases in total energy intake have been cited as factors contributing to rising trends in adult obesity [ 1 , 2 , 31 ] . in analyses
not shown here , we found that although increased leisure - time pa was associated with reduced obesity risks in both the apis and whites , adjusting for pa levels had little impact on the magnitude of racial / ethnic differentials in obesity rates .
indeed , because the apis had higher physical inactivity levels , adjusting for pa only widened racial / ethnic differentials in obesity .
use of public transport is associated with increased physical activity [ 31 , 32 ] . as shown in table 1 ,
all api groups are more likely than whites to use public transport for commuting to work .
the commuting patterns appear to be consistent with the racial / ethnic differentials in obesity reported here .
differences in dietary factors may partly explain racial / ethnic and immigrant differentials in obesity shown here .
as shown in table 1 , the apis have a higher intake of fruits and vegetables than the non - hispanic whites and the total population .
however , the filipinos and the hawaiians / pacific islanders are similar to the whites and are much less likely than the chinese and the asian indians to consume fruits / vegetables daily .
according to a recent study , immigrants in each racial / ethnic group had significantly lower total calorie and fat intake than those of their us - born counterparts .
moreover , immigrants ' likelihood of excess calorie and fat intake increased with longer duration of residence in the usa . in this study
, immigrants from the residual ethnic - immigrant category , who were primarily asian immigrants , had the lowest total calorie and fat intake of all the ethnic - immigrant groups . although lower ses groups have higher consumption of lower - quality diets and energy - dense foods , data on these dietary outcomes are lacking for api subgroups [ 33 , 34 ] .
future studies need to examine the impact of dietary variables in explaining obesity trends and differentials between racial / ethnic and immigrant groups shown here .
obesity and overweight prevalence estimates from nhis are derived from self - reported height and weight data , which may underestimate the actual prevalence among various racial / ethnic , immigrant , and socioeconomic groups [ 2 , 26 ] . during 20072010 , for example , 27.8% and 63.4% of us
adults were classified as obese and overweight , respectively , in the nhis , whereas the corresponding nhanes prevalences were 34.9% and 68.7% [ 1 , 11 , 26 ] .
thus , the estimates presented may , at best , represent the lower bounds of the obesity and overweight burden in whites and the api subgroups .
however , compared to the nhis - based analyses , the nhanes with its much smaller sample size can not permit detailed examinations of racial / ethnic , immigrant , and socioeconomic disparities in obesity such as those shown here .
second , dietary information in the nhis is only available for selected years , such as 2005 and 2010 , in which such data were collected as part of the cancer control supplements .
the nhis does not collect information on legal status of immigrants as well as more direct measures of acculturation such as ethnic - cultural identity , language , social networks , and dietary preferences [ 2 , 9 , 10 ] .
finally , because of the small sample sizes we did not examine if obesity patterns and trends among api subgroups differed by gender ; this needs to be examined in future studies . social environments , such as socioeconomic status , as well as physical and built environments , are the underlying determinants of obesity [ 2 , 23 , 3538 ] .
they influence obesity risks through their effects on the proximate behavioral factors of diet , physical activity , and sedentary behaviors [ 2 , 23 , 3538 ] .
we have shown the significant impact of ses on obesity and overweight risks among both the apis and the whites .
ethnic - minority and socially disadvantaged groups in the united states have lower access to neighborhood sidewalks , parks / playgrounds and green spaces , public transportation , and local grocery stores that carry healthy , affordable foods [ 23 , 24 , 35 ] . health policy measures must address these broader social and physical environments as a part of a national strategy to prevent obesity and reduce health inequalities across social and racial / ethnic groups [ 23 , 24 , 35 ] . in conclusion , continued inequalities in obesity according to race / ethnicity , immigrant status , and ses will likely have substantial impacts on future obesity and chronic disease patterns in the united states .
the united states has the highest rates of obesity and overweight in the industrialized world [ 5 , 27 , 39 ] .
our analysis shows that even the highest - educated and wealthiest asian americans are not immune to the rising obesity trend .
national efforts on obesity prevention and control must take into account considerable heterogeneity that exists among the apis in terms of both obesity prevalence and the related social and behavioral determinants .
the asian indians , the filipinos , and the hawaiians / pacific islanders have 210 times higher obesity and overweight prevalence than the chinese . except for chinese immigrants , an average asian american is likely to be overweight and the native hawaiian / pacific islander an obese adult .
indeed , the overall obesity and overweight prevalence for us adults and an overweight prevalence of 72% for the native hawaiians / pacific islanders and 76% for the pacific islander immigrants rank among the highest in the world [ 5 , 27 , 39 ] . continued monitoring of disparities in obesity and overweight prevalence among the asian / pacific islander americans should , therefore , be an essential feature of the national strategy to track progress towards eliminating health inequalities among all the americans [ 2 , 40 ] . | ### Summary:
: we examined trends in adult obesity and overweight prevalence among major asian / pacific islander ( api ) subgroups and the non - hispanic whites from 1992 to 2011 . using 19922011 national health interview surveys , obesity , overweight , and bmi differentials
were analyzed by logistic , linear , and log - linear regression . between 1992 and 2011 ,
obesity prevalence doubled for the chinese , the asian indians , the japanese , and the hawaiians / pacific islanders ; and tripled for the filipinos .
obesity prevalence among api adults tripled from 3.7% in 1992 to 13.3% in 2010 , and overweight prevalence doubled from 23.2% to 43.1% .
immigrants in each api subgroup had lower prevalence than their us - born counterparts , with immigrants ' obesity and overweight risks increasing with increasing duration of residence . during 20062011 ,
obesity prevalence ranged from 3.3% for chinese immigrants to 22.3% for the us - born filipinos and 41.1% for the native hawaiians / pacific islanders .
the asian indians , the filipinos , and the hawaiians / pacific islanders had , respectively , 3.1 , 3.8 , and 10.9 times higher odds of obesity than those of the chinese adults . compared with chinese immigrants ,
the adjusted odds of obesity were 3.54.6 times higher for the us - born chinese and the foreign - born filipinos , 9 times higher for the us - born filipinos and whites , 3.85.5 times higher for the us - born and foreign - born asian indians , and 21.9 times higher for the native hawaiians .
substantial ethnic heterogeneity and rising prevalence underscore the need for increased monitoring of obesity and obesity - related risk factors among api subgroups . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: cases of idiopathic recurrent benign aseptic meningitis were first described by mollaret . today , herpes simplex virus ( hsv )
a 40-year - old male was referred to our genitourinary medicine clinic with recurrent genital herpetic lesions .
one year after the first infection , he developed severe recurrent attacks of headache associated with meningitis symptoms .
the results of all radiological and biochemical tests were normal , but the patient reported a correlation between his attacks and genital herpes flare - ups .
we diagnosed the patient with mollaret s meningitis and started him on continuous suppressive acyclovir therapy , which resulted in marked clinical improvement .
mollaret s meningitis is a rare form of idiopathic recurrent aseptic meningitis that has a sudden onset , short duration , and spontaneous remission with unpredictable recurrence .
we believe that the presence of concurrent or recurrent mucocutaneous herpetic lesions can aid its diagnosis , prior to which , affected patients usually have many unnecessary investigations and treatments .
therefore , detailed sexual history should be sought in all patients with aseptic meningitis , and clinicians should also ask about history of recurrent headaches in all patients with recurrent herpetic anogenital lesions . continuous suppressive acyclovir therapy may reduce the frequency and severity of attacks and can dramatically improve lifestyle .
mollaret was the first to describe a rare form of meningitis that presented as recurrent and brief self - limiting attacks of fever , headache , vomiting , and meningeal irritation with no obvious etiology.1 subsequently , all cases of idiopathic recurrent aseptic meningitis ( ram ) were collectively called mollaret s meningitis.2 today , herpes simplex virus ( hsv ) type 2 ( hsv-2 ) is thought to be the commonest cause of mollaret s meningitis , underlying up to 84% of cases,3 although other infectious and noninfectious causes have also been described.2 however , its diagnosis remains challenging despite the use of new sophisticated diagnostic tools , and some authors have advised restricting the term mollaret s meningitis to cases with no confirmed etiology.2 the frequency and severity of attacks are variable , and severe forms can be incapacitating if appropriate antiviral therapies are not promptly used . here
, we describe a rare case of a patient with ram who presented with recurrent and severe self - limiting bouts of headache and responded well to suppressive antiviral therapy .
a 40-year - old man was referred to our genitourinary medicine clinic with chronic recurrent herpetic genital ulcers .
swabs taken from these initial lesions tested positive for hsv-2 and negative for hsv type 1 ( hsv-1 ) .
the patient had a past medical history of migraines that started in adulthood as unilateral headaches and were controlled by triptans and simple analgesics .
one year after his first genital infection , the patient started to develop severe holocranial headaches with distinct characteristics , which failed to respond to usual migraine therapy .
the headaches were associated with neck stiffness , mild photophobia , and bilateral pedal paresthesia , but there was no fever , vomiting , or other cranial or radicular neuropathy symptoms .
the patient went to the emergency department many times , but his biochemical markers and a computed tomography brain scan were normal .
the patient repeatedly refused diagnostic lumbar puncture , but serologic assays ( hsv-1 , cmv [ cytomegalovirus ] , vzv [ varicella - zoster virus ] , and human immunodeficiency virus ) were negative apart from a positive hsv-2 immunoglobulin g titer .
he was clinically diagnosed with meningitis and commenced on empirical parenteral ceftriaxone and acyclovir , to which he responded very well .
his attacks often recurred two to three times per month and were usually self - limiting in 35 days , regardless of their severity , with no residual functional impairment .
the attacks were often triggered by emotional stress or heat and were sometimes preceded by genital herpetic eruptions , for which he was referred to our clinic .
the distinctive correlation between his meningitic recurrent headaches and recurrent genital lesions as well as his normal previous diagnostic tests raised our suspicion of a possible mollaret s meningitis diagnosis .
we placed the patient on a continuous suppressive oral acyclovir therapy regimen ( 400 mg twice daily ) , which reduced the frequency of his headaches to one to two attacks every 23 months , each lasting 13 days .
attempts to reduce the total daily dose to 400 mg or 600 mg have led to a remarkable increase in the severity and frequency of his acute relapses , so the total daily dose of 800 mg is being sustained indefinitely with regular follow - up in our clinic .
in 1982 , hsv was linked to mollaret s meningitis when hsv-1 was detected in the cerebrospinal fluid of an affected patient.4 today , hsv-2 ( and less often hsv-1 ) is believed to be a leading cause of ram .
its pathogenesis is not fully understood and may be due to retrograde seeding reactivation of the latent virus nested in the sensory ganglia.5 aseptic meningitis is known to complicate primary genital herpes infection in 36% of women and 11% of men , but meningitis following subclinical infections has also been reported.6,7 confirmed hsv-2 acute meningitis can recur in 19%27% of cases , especially in hsv-1 seronegative patients similar to our case.3,8 hsv-1 seroprevalence is declining in many countries , including the uk , and the incidence of recurrent hsv-2-associated meningitis may be increasing.3,9 practical diagnostic criteria for mollaret s meningitis historically included absence of any detectable etiological agents.10 however , occurrence of concurrent or separate episodes of recurring mucocutaneous herpetic lesions , or detection of hsv dna in the cerebrospinal fluid which can be positive in up to 82% of samples taken 25 days after the onset of symptoms3 can aid diagnosis
recurrent attacks can be preceded by nonspecific self - limiting constitutional symptoms as paresthesias , neuropathic pain , and arthralgias.3,6 mollaret s meningitis usually resolves after a period of 35 years , but cases with longer periods , similar to our patient , have also been reported.2,11 the use of long - term suppressive rather than episodic anti - hsv therapy has shown satisfactory results in controlling hsv-2-associated mollaret s meningitis , but this practice is not yet supported by high quality evidence.2,7 in our patient and other reported cases , daily acyclovir or valacyclovir has been generally well tolerated with good bioavailability , and has reduced the severity and frequency of attacks.7,11 other medications such as colchicine and indomethacin have also been tried , but firm evidence of their efficacy is still lacking.12,13
incidence of hsv-2-associated recurrent meningitis is suspected to be increasing . however , most patients have unnecessary investigations and treatments prior to diagnosis , and some patients remain undiagnosed .
history of herpetic anogenital infections should be sought in all patients with recurrent meningitic headaches and vice versa .
continuous antiviral therapy appears to reduce the frequency of attacks and can dramatically improve lifestyle . | ### Summary:
: introductioncases of idiopathic recurrent benign aseptic meningitis were first described by mollaret . today , herpes simplex virus ( hsv )
is considered the cause of most cases of mollaret s meningitis.case reporta 40-year - old male was referred to our genitourinary medicine clinic with recurrent genital herpetic lesions .
he had hsv-2-positive genital ulcers 8 years earlier .
one year after the first infection , he developed severe recurrent attacks of headache associated with meningitis symptoms .
the results of all radiological and biochemical tests were normal , but the patient reported a correlation between his attacks and genital herpes flare - ups .
we diagnosed the patient with mollaret s meningitis and started him on continuous suppressive acyclovir therapy , which resulted in marked clinical improvement.discussionmollarets meningitis is a rare form of idiopathic recurrent aseptic meningitis that has a sudden onset , short duration , and spontaneous remission with unpredictable recurrence .
we believe that the presence of concurrent or recurrent mucocutaneous herpetic lesions can aid its diagnosis , prior to which , affected patients usually have many unnecessary investigations and treatments .
therefore , detailed sexual history should be sought in all patients with aseptic meningitis , and clinicians should also ask about history of recurrent headaches in all patients with recurrent herpetic anogenital lesions . continuous suppressive acyclovir therapy may reduce the frequency and severity of attacks and can dramatically improve lifestyle . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: aortic dissection is a rare condition , with annual incidence of three to eight cases/100,000 people [ 13 ] , which is associated with high morbidity and mortality .
type a aortic dissections are viewed as surgical emergencies , but the treatment of type b aortic dissections ( tbads ) , which account for about one - third of total aortic dissections , is more variable .
acute type b dissections that are complicated by visceral or limb ischemia , aortic rupture , refractory pain , or rapidly expanding dissection also require surgical intervention . in the absence of such complications , which is the case for seventy percent of patients with acute type b dissection , medical therapy with antihypertensives
has been the standard of care . in 2005 , the us food and drug administration approved thoracic endovascular aortic repair ( tevar ) for the repair of thoracic aortic aneurysms , and surgeons have increasingly been using tevar off - label to treat tbad .
the high mortality rates associated with traditional open thoracotomy surgical repair of complicated tbad have driven the increased adoption of the less invasive tevar in complicated tbad .
the possibility that tevar can facilitate better remodeling of the aorta than medical therapy and avert late aortic rupture has stimulated its use in treating uncomplicated tbad patients , who traditionally would have received medical therapy alone [ 8 , 9 ] .
most studies on the outcomes of tevar have been small , single center studies [ 10 , 11 ] , or meta - analyses with potential selection biases [ 5 , 12 ] , but sachs et al .
were the first to conduct a large population study utilizing the nationwide inpatient sample which compared the outcomes of treatment with tevar versus open surgery in tbad patients .
, as we include an additional year of data ( 2008 ) and utilize a propensity score matching approach that more effectively controls for differences between treatment groups than standard multivariate analysis .
we used the nationwide inpatient sample ( nis ) database to identify patients with type b thoracic aortic dissections who underwent surgical repair between 2005 and 2008 .
the nis is the largest all - payer inpatient care database and contains discharge data from over eight million hospitalizations per year , which is approximately twenty percent of all hospitalizations in the united states
.
international classification of diseases , the 9th edition ( icd-9 ) diagnosis codes were used to identify all patients in the nis with thoracic aortic dissections ( 441.01 ) .
patients with thoracic dissections treated surgically were separated from those receiving medical therapy alone by using procedure codes for endovascular stent graft repair ( 39.73 ) or open repair ( 38.34 , 38.45 ) .
the icd-9 procedure code for tevar was introduced in september 2005 , which limited our study to the period from 2005 to 2008 . additionally , we excluded all patients with diagnosis codes for aortic aneurysms ( 441.1 to 441.9 ) , to better restrict the analysis to patients with acute dissection .
we isolated type b aortic dissections from type a aortic dissections using criteria developed by sachs et al . ,
in which patients with procedure codes for cardioplegia ( 39.63 ) , valve repair ( 35.0035.99 ) , or operations on vessels of the heart ( 36.0036.99 , 37.0 , 37.2 , 37.3137.90 , 37.9337.99 ) , who were more likely to have type a dissections , were excluded .
we further stratified the patients with type b dissections based on whether they were admitted emergently or electively to the hospital .
the following patient demographics and hospital characteristics were identified : age , gender , hospital bed size , hospital teaching status , and annual volume of tevar performed per hospital .
the following comorbidities were assessed : cardiac arrhythmias , chronic congestive heart failure ( chf ) , coronary artery disease , valvular heart disease , chronic pulmonary disease , chronic renal failure , coagulopathy , deficiency anemias , diabetes , hypertension , obesity , neurological disorders , paralysis , and peripheral vascular disease ( table 1 ) . in order to control for imbalances of patient characteristics and institutional characteristics among the treatment groups that might influence treatment outcome , we used a propensity scoring method to establish matched cohorts .
a propensity score , which was assigned to each hospitalization , was based on a multivariate logistic regression model that examined the impact of thirty variables ( patient demographics , comorbidities , and hospital characteristics ) on the likelihood of treatment assignment .
patients with similar propensity scores in the two treatment groups were matched using a 1-to-1 scheme without replacement , using 8-to-1 digit match .
outcomes were compared between propensity score - matched cohorts of patients undergoing tevar and open surgery .
the primary outcomes measured were in - hospital mortality , in - hospital complications , and length of stay ( los ) .
complications included acute renal failure , cardiac complications , neurological complications , paraplegia , posthemorrhagic anemia , postoperative hemorrhage , pulmonary complications , stroke , and thrombectomy / embolectomy .
the icd-9 diagnosis codes used to code for comorbidities and complications are provided in table 1 .
paired t - test was used for comparisons of continuous variables and the mcnemar test for categorical variables in matched cohorts .
all statistical analyses were performed using sas 9.2 software ( sas institute inc . , cary , nc ) .
during the period 20052008 , 4752 emergently admitted patients with tbad were treated surgically : 3427 ( 72.1% ) underwent open repair , and 1325 ( 27.9% ) underwent tevar ( table 2 ) . during this same period of time ,
1247 electively admitted patients with tbad were treated surgically : 680 ( 54.5% ) underwent open repair , and 567 ( 45.5% ) underwent tevar ( table 3 ) . among those admitted emergently , tevar recipients were significantly more likely to have coronary artery disease , chronic pulmonary disease , diabetes , peripheral vascular disease and to be treated in hospitals with higher tevar volume .
in contrast , open repair patients had higher rates of cardiac arrhythmia , valvular disease , and coagulopathy ( table 2 ) . among electively admitted patients ,
tevar recipients were older , had higher rates of diabetes , hypertension , and were more likely to receive their care at higher tevar volume hospitals .
open repair patients had significantly higher rates of valvular disease and coagulopathy ( table 2 ) .
the p value for the hosmer - lemeshow goodness - of - fit test of the propensity score model was 0.605 , and the c statistic was 0.828 .
in - hospital mortality among emergently admitted patients was significantly higher among open repair recipients than in tevar recipients ( 17.5% versus 10.8% , p = .045 ) .
open repair was associated with higher rates of acute renal failure ( 27.3% versus 16.8% , p = .008 ) , cardiac complications ( 16.6% versus 8.9% , p = .029 ) , and posthemorrhagic anemia ( 22.6% versus 12.1% , p = .006 ) ( table 4 ) .
demographic characteristics and comorbid conditions were similar between these two matched cohorts ( table 3 ) .
the p value for the hosmer - lemeshow goodness - of - fit was 0.137 , and the c statistic was 0.858 .
in - hospital mortality was not significantly different among recipients of tevar and open surgery ( 5.6% versus 3.3% , p = .464 ) .
open repair recipients did have higher rates of in - hospital complications such as acute renal failure ( 13.0% versus 1.7% , p = .021 ) , cardiac complications ( 15.8% versus 3.6% , p = .021 ) , posthemorrhagic anemia ( 17.3% versus 3.5% , p = .017 ) , postoperative hemorrhage ( 19.1% versus 5.2% , p = .009 ) , and pulmonary complications ( 35.0%
versus 16.2% , p = .034 ) ( table 5 ) . to determine whether outcomes of tevar treatment for tbad are related to overall hospital experience with this procedure ( i.e. , for aneurysms and dissection ) , we grouped hospitals by overall tevar volume and compared in - hospital tbad mortality rates .
we limited the analysis to tbad patients admitted emergently to help control for patient differences ( figure 1 ) .
the cut - off volumes for the six tevar volume groups were established so that each group would have a similar number of emergently admitted tbad patients treated with tevar .
the lowest volume group ( 14 tevar procedures / year ) has the highest mortality rate ( 13.4% ) .
the highest volume group ( over 55 tevar procedures / year ) has the lowest mortality rate ( 2.9% ) .
the tbad mortality rate , which was relatively uniform at lower volumes , declined steadily as hospital tevar volumes reached 30 per year .
in fact the tbad in - hospital mortality rate for hospitals performing less than 30 procedures per year was more than twice the rate seen in hospitals that performed more than 30 per year ( < 30 = 11.3% , 30 = 4.8% ; p
we looked at tevar and open repair use for type b aortic dissection over a four - year period and compared outcomes . to control for selection bias we used a propensity score model to create matched cohorts of patients for the comparisons . among patients treated emergently , in - hospital mortality was significantly lower with tevar than open surgery ( 10.8% versus 17.5% , p = .045 ) .
this finding is consistent with other reports in the literature . in patients with complicated tbad , zeeshan et al .
= .006 ) among tevar recipients ( n = 45 ) compared to open repair recipients ( n = 20 ) .
also , in patients with complicated tbad , international registry of acute aortic dissection ( irad ) investigators demonstrated significantly lower in - hospital mortality among tevar recipients ( 10.6% versus 33.9% , p = .002 ) as well as lower rates of stroke and acute renal failure ( 20.8% versus 40.0% , p = .04 ) .
in a recent meta - analysis of tevar use in complicated acute type b dissections , luebke and brunkwall reported an in - hospital mortality rate of 11.5% .
in contrast to what we observed with emergently admitted patients , tevar did not appear to have an impact on the mortality of nonemergent tbad patients ( 3.3% versus 5.6% , p = .464 ) .
however , the more relevant question for patients with uncomplicated type b aortic dissection is how the outcomes of tevar compare to medical therapy , the standard of care for this disease
. unfortunately , our study could not address this question as large datasets like the nis do not contain anatomical information about the disease , which would be needed to distinguish type a and type b dissections .
our ability to make this distinction in surgical patients relied on the coding of associated aortic arch and aortic valve procedures , commonly required to repair type a dissections .
it is clear that comparing the outcomes of medical therapy to tevar for uncomplicated type b dissections will require primary data collection , preferably in the form of a randomized controlled trial . in looking at the relationship between tevar volume and outcome of treatment in emergently
treated tbad patients , we observed over a fourfold difference in mortality ( 13.4% versus 2.9% ) between the lowest volume group ( 14 tevar procedures / year ) and the highest volume group ( over 55 tevar procedures / year ) .
hospitals that perform less than thirty tevar procedures annually had more than twofold higher in - hospital mortality for emergent tbad patients than hospitals performing more than 30 tevar procedures a year ( 11.3% versus 4.8% , p = .047 ) .
although this analysis did not adjust for differences between the volume groups , which would have required a larger sample size , our restricting the analysis to the subgroup who was hospitalized emergently does help to minimize the differences between the volume groups .
our finding is consistent with others . in a meta - analysis of 609 patients undergoing tevar for aortic dissection ( 96% tbad ) , eggebrecht et al
. concluded that surgeons ' experience with tevar influenced outcomes because hospitals that performed more than twenty tevar procedures had significantly lower 30-day mortality than hospitals with less than twenty procedures ( 3.2% versus 8.5% ; p < .001 ) .
one limitation of our study is that it is observational and carries all the potential biases inherent to such studies .
for instance , the subgroups of patients who underwent tevar and open repair differed substantially ( tables 2 and 3 ) .
we adjusted our comparisons for such differences by comparing propensity score - matched cohorts ; however , it is possible that there is still some bias in the analyzed cohorts due to confounders that were not recognized .
furthermore , the comorbidity data , which was the basis for the comparisons between treatment groups , was originally collected for administrative purposes and subject to coding errors . another important limitation to our study
complications unique to treatment with tevar , such as endoleak , graft migration , and retrograde type a dissection , can contribute to mortality and complications after a patient is discharged from the hospital [ 16 , 17 ] .
longitudinal analysis in the form of randomized controlled clinical trials is needed in order to determine the long - term outcomes of tevar used for type b dissections and to ascertain whether favorable in - hospital outcomes for tevar in emergently admitted tbad patients persist over time .
the recent instead trial was the first prospective , randomized , and controlled comparison of tevar and medical treatment in uncomplicated tbad , and it showed that there was no difference in one - year mortality between tevar and medical therapy alone , despite significantly greater aortic remodeling in tevar .
however , instead was not appropriately powered to find a difference with the high survival rates they observed in the medical therapy group .
moreover , instead did not restrict enrollment to current definitions of acute uncomplicated tbad , which many believe is the subgroup with greatest chance of showing a benefit to tevar .
our study demonstrates that endovascular repair is becoming an important treatment modality for type b dissection .
approximately 31.5% of the surgical repairs of tbad in the united states are performed using this modality .
our analysis of the nis dataset , using propensity score matching , demonstrated that tevar outperforms open surgery among emergently admitted patients with type b aortic dissection , both in terms of in - hospital mortality and morbidity .
this was not the case for electively admitted patients , where tevar appeared to impart a short - term morbidity benefit only .
we observed a significant volume outcome relationship between overall tevar use and in - hospital mortality rates , which , if confirmed through additional studies , should guide institutional targets for optimal outcomes of therapy . | ### Summary:
: objective . to identify national outcomes of thoracic endovascular aortic repair ( tevar ) for type b aortic dissections ( tbads )
.
methods . the nationwide inpatient sample database was examined from 2005 to 2008 using icd-9 codes to identify patients with tbad who underwent tevar or open surgical repair .
we constructed separate propensity models for emergently and electively admitted patients and calculated mortality and complication rates for propensity score - matched cohorts of tevar and open repair patients .
results . in - hospital
mortality was significantly higher following open repair than tevar ( 17.5% versus 10.8% , p = .045 ) in emergently admitted tbad .
there was no in - hospital mortality difference between open repair and tevar ( 5.6% versus 3.3% , p = .464 ) for elective admissions .
hospitals performing thirty or more tevar procedures annually had lower mortality for emergent tbad than hospitals with fewer than thirty procedures .
conclusions .
tevar produces better in - hospital outcomes in emergent tbad than open repair , but further longitudinal analysis is required . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: in a flame - dried argon - purged
round - bottom flask containing 4 molecular sieves ( 300 mg ) were
added tbai ( 140 mg , 0.38 mmol , 4.5 equiv ) , cholesterol ( 32 mg , 0.08
mmol , 1.0 equiv ) , and anhydrous dichloromethane ( 2.5 ml ) .
base ( 90 l , 0.51 mmol , 6.0 equiv ) was then added to the solution ,
and the reaction was stirred for 30 min . in a separate flame - dried
argon - purged round - bottom flask
was placed per - o - trimethylsilylated
glucose ( 140 mg , 0.25 mmol ) , which was
azeotroped with anhydrous benzene ( 2 3 ml ) , and then anhydrous
chloroform was added and removed under reduced pressure ( 2
3 ml ) .
the per - o - tms sugar was placed under vacuum for at least 2 h prior to use , but typically
was dried on vacuum overnight . once dried according to the above protocol ,
the reaction was diluted with anhydrous dichloromethane ( 2.5 ml ) ,
and tmsi ( 40 l , 0.28 mmol , 3.3 equiv ) was added and allowed
to react for 10 min at rt .
the in situ generated glucosyl iodide was
then transferred via cannula into the acceptor flask and allowed to
stir for 2 days at rt .
the solvent was then filtered to remove the
molecular sieves and concentrated under reduced pressure .
a 1:1 ratio
of ethyl acetate and hexanes ( 20 ml ) was then added to the round - bottom
flask , and the flask was cooled in a dry ice / acetone bath , causing
the excess tbai to precipitate .
the solid was filtered , and the solution
was again concentrated to give an oil .
methanol ( 5 ml ) and dowex 50wx8 - 200
acidic resin ( 300 mg ) were then added , and the reaction was stirred
for 2 h. initially , the crude reaction mixture was acetylated to separate
the anomers and to obtain an accurate : ratio .
the acetylated
mixture was purified
by hplc using a silica microsorb normal phase 250 10 mm column
and a gradient mobile phase starting with 20% ethyl acetate in hexanes
with gradual polarity increasing to 40% ethyl acetate in hexanes over
a 23 min time period and a flow rate of 4 ml per min .
the -anomer
had an hplc retention time of 14.4 min and was obtained as a white
powder .
the purified compound was then recrystallized from diethyl
ether and methanol to afford glasslike , rod - shaped crystals .
h nmr ( 800 mhz , cdcl3 ) : 0.67 ( s , 3h ) , 0.85 ( d , j = 6.6
hz , 3h ) , 0.86 ( d , j = 6.6 hz , 3h ) , 0.91 ( d , j = 6.6 hz , 3h ) , 1.02 ( s , 3h ) , 1.031.17 ( m , 9h ) ,
1.231.29 ( m , 2h ) , 1.321.39 ( m , 2h ) , 1.411.58
( m , 9h ) , 1.751.85 ( m , 2h ) , 1.952.00 ( m , 2h ) , 2.01
( s , 3h ) , 2.03 ( s , 3h ) , 2.05 ( s , 3h ) , 2.08 ( s , 3h ) , 2.30 ( ddd , j = 2.2 , 4.9 , 13.2 hz , 1h ) , 3.362.38 ( m , 1h ) , 3.403.44
( m , 1h ) , 4.11 ( dd , j = 2.2 , 12.2 hz , h6 , 1h ) , 4.14
( ddd , j = 2.2 , 4.8 10.2 hz , h5 , 1h ) , 4.23 ( dd , j = 4.8 , 12.2 hz , h6 , 1h ) , 4.80 ( dd , j = 3.8 , 10.2 hz , h2 , 1h ) , 5.03 ( app .
t , j = 10.2
hz , h4 , 1h ) , 5.22 ( d , j = 3.8 hz , h1 , 1h ) , 5.335.34
( m , 1h ) , 5.48 ( app .
c nmr ( 200 mhz , cdcl3 ) : 170.9 , 170.4 ,
170.3 , 169.9 , 140.4 , 122.3 , 94.3 ( c1 ) , 78.9 , 71.2 ( c2 ) , 70.3 ( c3 ) ,
68.8 ( c4 ) , 67.3 ( c5 ) , 62.2 ( c6 ) , 56.8 , 56.2 , 50.2 , 42.4 , 40.1 , 39.8 ,
39.6 , 37.1 , 36.8 , 36.3 , 35.9 , 32.1 , 32.0 , 28.4 , 28.2 , 28.0 , 24.4 ,
24.0 , 23.0 , 22.7 , 21.2 , 20.94 , 20.91 , 20.9 , 20.8 , 19.5 , 18.8 , 12.0 .
hrms ( esi - ion trap ) m / z : [ m + na ] calcd for c41h64o10na 739.4397 ;
found 739.4404 .
the -anomer
had an hplc retention
time of 16.8 min and was obtained as a white powder and was then recrystallized
from diethyl ether and methanol to afford glasslike , rod - shaped crystals .
h nmr ( 800 mhz , cdcl3 ) : 0.66 ( s , 3h ) , 0.85 ( d , j = 6.6
hz , 3h ) , 0.86 ( d , j = 6.0 hz , 3h ) , 0.91 ( d , j = 6.0 hz , 3h ) , 0.98 ( s , 3h ) , 1.001.17 ( m , 9h ) ,
1.221.28 ( m , 2h ) , 1.321.37 ( m , 2h ) , 1.411.54
( m , 5h ) , 1.561.62 ( m , 3h ) , 1.791.90 ( m , 3h ) , 1.962.06
( m , 2h ) , 2.00 ( s , 3h ) , 2.01 ( s , 3h ) , 2.04 ( s , 3h ) , 2.07 ( s , 3h ) , 2.162.20
( m , 1h ) , 2.25 ( ddd , j = 2.4 , 4.8 , 13.3 hz , 1h ) , 3.48
( dp , j = 0.6 , 4.8 , 9.6 hz , 1h ) , 3.67 ( ddd , j = 2.4 , 4.8 , 9.6 hz , h5 , 1h ) , 4.11 ( dd , j = 2.4 , 12.6 hz , h6 , 1h ) , 4.25 ( dd , j = 4.8 , 12.6
hz , h6 , 1h ) , 4.59 ( d , j = 7.8 hz , h1 , 1h ) ,
4.95 ( dd , j = 8.0 , 9.6 hz , h2 , 1h ) , 5.07 ( app .
t , j = 9.6 hz , h4 , 1h ) , 5.19 ( app .
t , j =
9.6 , hz , h3 , 1h ) , 5.355.36 ( m , 1h ) .
c nmr ( 200
mhz , cdcl3 ) : 170.8 , 170.5 , 169.5 , 169.4 , 140.5 ,
122.3 , 99.8 ( c1 ) , 80.2 , 73.0 ( c3 ) , 71.8 ( c5 ) , 71.6 ( c2 ) , 68.7 ( c4 ) ,
62.2 ( c6 ) , 56.9 , 56.3 , 50.3 , 42.5 , 39.9 , 39.7 , 39.1 , 37.3 , 36.9 , 36.3 ,
35.9 , 32.1 , 32.0 , 29.6 , 28.4 , 28.2 , 24.4 , 24.0 , 23.0 , 22.7 , 21.2 ,
20.9 , 20.87 , 20.8 , 20.76 , 19.5 , 18.9 , 12.0 . hrms ( esi - ion trap ) m / z : [ m + nh4 ] calcd
for c41h68 no10 734.4843 ; found 734.4843 .
alternatively , the crude mixture could be purified by flash column
chromatography using a 9:1 dichloromethane : methanol solvent system
to afford compound ( 1 ) ( 35 mg , 0.06 mmol , 78% yield ) .
h nmr noesy presaturation
1d to suppress water ( 4.23 ppm ) and the spectrum was locked to cd3od ( 800 mhz , cdcl3 : cd3od
( 3:1 ) ) : 0.49 ( s , 3h ) , 0.67 ( d , j = 6.6 hz ,
3h ) , 0.68 ( d , j = 6.6 hz , 3h ) , 0.74 ( d , j = 6.6 hz , 3h ) , 0.780.81 ( m , 1h ) , 0.82 ( s , 3h ) , 0.830.99
( m , 8h ) , 1.051.13 ( m , 1h ) , 1.141.18 ( m , 3h ) , 1.241.39
( m , 8h ) , 1.641.66 ( m , 1h ) , 1.671.69 ( m , 1h ) , 1.721.74
( m , 1h ) , 1.761.79 ( m , 1h ) , 1.821.83 ( m , 1h ) , 2.142.17
( m , 2h ) , 3.22 ( dd , j = 3.8 , 10.2 hz , h2 , 1h ) , 3.23
( app .
t , j = 9.6 hz , h4 , 1h ) , 3.283.32 ( m ,
1h ) , 3.47 ( app .
t , j = 9.6 hz , h3 , 1h ) , 3.463.49
( m , h5 , 1h ) , 3.583.60 ( m , h6 , h6 , 2h ) , 4.79 ( d , j = 3.8 hz , h1 , 1h ) , 5.155.20 ( m , 1h ) .
c nmr ( 200 mhz , cdcl3 : cd3od ( 3:1 ) ) :
140.4 , 121.8 , 96.7 ( c1 ) , 77.5 , 73.8 ( c3 ) , 71.8 ( c2 ) , 71.5 ( c5 ) , 70.0
( c4 ) , 61.3 ( c6 ) , 56.6 , 55.9 , 49.9 , 42.1 , 39.8 , 39.6 , 39.3 , 36.8 , 36.5 ,
36.0 , 35.6 , 31.7 , 31.6 , 28.0 , 27.8 , 27.4 , 24.0 , 23.6 , 22.5 , 22.2 ,
20.8 , 19.0 , 18.4 , 11.6 .
hrms ( maldi - tof ) m / z : [ m + na ] calcd for c33h56o6na 571.3969 ; found 571.3937 .
compound 1 ( 20.0 mg , 0.036 mmol ) was placed
into an oven - dried screw cap vial .
then , anhydrous acetone ( 0.9 ml ) and commercial lipase novozym 435
( 36 mg on solid support ) were added to the vial , followed by myristic
vinyl ester ( 6.0 equiv , 60 l ) .
the vial was then placed on
a thermoplate shaker at 40 c for 18 h. upon completion of the
reaction , the solution was decanted into a round - bottom flask and
the enzyme was rinsed twice with methanol , followed by chloroform .
this solid was purified by flash chromatography using 100%
hexanes , and the characterization data matched that of what was previously
reported .
compound 5 ( 10.0 mg , 0.018 mmol ) was placed
into an oven - dried screw cap vial .
then , anhydrous pyridine ( 60 l ) , followed by thf ( 240 l ) ,
was added to give a m = 0.1 concentration of 13 .
then ,
commercial lipase novozym 435 ( 10 mg on solid support ) was added to
the vial , followed by myristic vinyl ester ( 18.0 equiv , 95 l ,
0.32 mmol ) .
the vial was then placed on a thermoplate shaker at 40
c for 4 days , after which the solution was diluted with chloroform
and decanted into a round - bottom flask .
the organic solvents were combined
and concentrated to afford a white solid , which was purified by flash
chromatography on a 3.6 cm diameter glass column that was 25.5 cm
long plugged with cotton and filled with 150 ml of silica .
a gradient
solvent system of 100% hexanes ( 100 ml ) with increasing polarity to
1:1 hexanes : ethyl acetate ( 100 ml ) , followed by 100% ethyl acetate
( 100 ml ) to remove the excess fatty acid , which does not stain on
the tlc plate , was used . after using 100 ml of each solvent ratio ,
a 9:1 ethyl acetate : methanol solvent system
was used to elute compound 4 ( 10 mg , 0.014 mmol ) in 77% yield .
h nmr ( 800 mhz , cdcl3 ) : 0.67 ( s , 3h ) , 0.86 ( d , j = 6.6 hz , 3h ) , 0.87 ( d , j = 6.6 hz , 3h ) , 0.89 ( t , j = 7.2 hz , 3h ) , 0.92 ( d , j = 6.6 hz , 3h ) ,
0.960.99 ( m , 1h ) , 1.00 ( s , 3h ) , 1.021.17 ( m , 7h ) ,
1.251.27 ( m , 22h ) , 1.271.36 ( m , 2h ) , 1.421.62
( m , 13h ) , 1.811.89 ( m , 4h ) , 1.952.02 ( m , 2h ) , 2.312.39
( m , 4h ) , 3.483.50 ( m , 1h ) , 3.743.76 ( m , h2 , h3 , 2h ) ,
3.953.96 ( m , h4 , 1h ) , 4.07 ( app .
t , j = 4.8
hz , h5 , 1h ) , 4.21 ( dd , j = 8.0 , 12.0 hz , h6 , 1h ) ,
4.41 ( dd , j = 4.8 , 12.0 hz , h6 , 1h ) , 5.06
( d , j = 4.0 hz , h1 , 1h ) , 5.355.36 ( m , 1 h ) .
c nmr ( 200 mhz , cdcl3 ) : 174.1 , 140.4 ,
122.4 , 97.3 ( c1 ) , 78.6 , 71.3 ( c3 ) , 69.6 ( c2 ) , 69.0 ( c4 ) , 68.3 ( c5 ) ,
63.5(c6 ) , 56.8 , 56.3 , 50.2 , 42.4 , 40.2 , 39.8 , 39.6 , 37.1 , 36.8 , 36.3 ,
35.9 , 34.4 , 32.1 , 32.0 , 31.9 , 29.9 , 29.89 , 29.85 , 29.84 , 29.8 , 29.53 ,
29.5 , 29.4 , 28.4 , 28.2 , 28.1 , 25.1 , 24.4 , 24.0 , 23.0 , 22.9 , 22.7 ,
21.6 , 19.5 , 18.8 , 14.3 , 12.0 .
hrms ( esi - ion trap ) m / z : [ m + na ] calcd for c47h82o7na 781.5958 ; found 781.6014 . in a flame - dried
argon - purged round - bottom flask containing
4 molecular sieves ( 300 mg ) were added tbai ( 140 mg , 0.38 mmol ,
1.5 equiv ) , cholesterol ( 32 mg , 0.083 mmol , 0.3 equiv ) , and anhydrous
dichloromethane ( 2.5 ml ) .
hnig s base ( dipea ) ( 90 l ,
0.51 mmol , 2.0 equiv ) was then added to this solution , which was stirred
for 30 min . in a separate flame - dried argon - purged round - bottom flask
was placed per - o - trimethylsilylated galactose made
from the synthetic protocol of bhat and gervay - hague ( 140 mg , 0.25 mmol ) and azeotroped with anhydrous chloroform
( 2 3 ml ) .
after azeotroping , the sugar was placed under vacuum
for at least 2 h prior to use .
the resulting residue was then diluted
with anhydrous dichloromethane ( 2.5 ml ) , and tmsi ( 40 l , 0.28
mmol , 1.1 equiv ) was added and allowed to react for 10 min .
the in
situ generated galactosyl iodide was then transferred via cannula
into the acceptor flask and allowed to stir for 2 days at rt .
the
solvent was then filtered to remove the molecular sieves , and the
solvent was removed under reduced pressure
. a 1:1 ratio of ethyl acetate
and hexanes ( 20 ml ) was then added to the round - bottom flask , and
the flask was cooled using dry ice .
the cooling helped solidify the
tbai , which was then filtered off , and the solution was again concentrated .
methanol ( 5 ml ) and dowex 50wx8 - 200 acidic resin ( 300 mg ) were then
added , and the mixture was stirred for 2 h. the solution was then
filtered to remove the acidic resin and concentrated under reduced
pressure .
the crude reaction mixture was then acetylated to identify
the :-ratio of the glycosylation .
the -anomer of the cholesteryl galactoside was further purified
by hplc using a silica microsorb normal phase 250 10 mm column
and a gradient mobile phase starting with 20% ethyl acetate in hexanes
with gradual polarity increasing to 50% ethyl acetate in hexanes over
a 20 min time period and a flow rate of 4 ml per min .
it had an hplc
retention time of 9.6 min and was obtained as a white foam .
h nmr ( 800 mhz , cdcl3 ) :
0.68 ( s , 3h ) , 0.85 ( d , j = 6.6 hz , 3h ) , 0.86
( d , j = 6.6 hz , 3h ) , 0.91 ( d , j =
6.6 hz , 3h ) , 0.961.01 ( m , 1h ) , 1.02 ( s , 3h ) , 1.031.14
( m , 8h ) , 1.231.28 ( m , 2h ) , 1.311.38 ( m , 2h ) , 1.441.52
( m , 7h ) , 1.531.56 ( m , 2h ) , 1.741.77 ( m , 1h ) , 1.811.85
( m , 2h ) , 1.962.01 ( m , 1h ) , 1.99 ( s , 3h ) , 2.04 ( s , 3h ) , 2.07
( s , 3h ) , 2.13 ( s , 3h ) , 2.30 ( ddd , j = 2.2 , 4.9 , 13.2
hz , 1h ) , 3.342.38 ( m , 1h ) , 3.403.44 ( m , 1h ) , 4.07
( dd , j = 7.2 , 11.2 hz , h6 , 1h ) , 4.11 ( dd , j = 5.6 , 11.2 hz , h6 , 1h ) , 4.34 ( app t , j = 7.2 hz , h5 , 1h ) , 5.06 ( dd , j = 4.0 ,
11.2 hz , h2 , 1h ) , 5.25 ( d , j = 4.0 hz , h1 , 1h ) , 5.35
( dd , j = 3.2 , 11.2 hz , h3 , 1h ) , 5.355.36
( m , 1h ) , 5.45 ( dd , j = 1.6 , 3.2 hz , h4 , 1h ) .
c nmr ( 200 mhz , cdcl3 ) : 170.6 , 170.5 ,
170.4 , 170.2 , 140.5 , 122.3 , 95.0 ( c1 ) , 78.9 , 68.5 ( c2 ) , 68.4 ( c4 ) ,
67.8 ( c3 ) , 66.4 ( c5 ) , 62.1 ( c6 ) , 56.8 , 56.3 , 50.3 , 42.5 , 40.1 , 39.9 ,
39.7 , 37.1 , 36.8 , 36.3 , 35.9 , 32.1 , 32.0 , 29.8 , 28.4 , 28.2 , 24.4 ,
24.0 , 23.0 , 22.7 , 21.2 , 21.0 , 20.9 , 20.8 , 20.8 , 19.5 , 18.9 , 12.0 .
hrms ( esi - ion trap ) m / z : [ m + na ] calcd for c41h64o10na 739.4397 ;
found 739.4404 .
alternatively , the crude solid after removing
the trimethylsilyl protecting groups could be purified with a 9:1
dichloromethane : methanol solvent system , and the white powder was
collected to afford the target compound ( 5 ) ( 39 mg , 0.071
mmol , 85% ) .
the h nmr utilized noesy presaturation 1d
to suppress water ( 4.23 ppm ) and the spectrum was locked to cd3od .
h nmr ( 800 mhz , cdcl3 :
cd3od ( 3:1 ) ) : 0.53 ( s , 3h ) , 0.70 ( d , j = 6.6 hz , 3h ) , 0.71 ( d , j = 6.6 hz , 3h ) , 0.77 ( d , j = 6.6 hz , 3h ) , 0.760.79 ( m , 1h ) , 0.85 ( s , 3h ) ,
0.871.03 ( m , 8h ) , 1.081.13 ( m , 5h ) , 1.161.23
( m , 3h ) , 1.271.44 ( m , 8h ) , 1.661.68 ( m , 1h ) , 1.691.72
( m , 1h ) , 1.721.73 ( m , 1h ) , 1.761.79 ( m , 1h ) , 1.801.87
( m , 1h ) , 2.192.20 ( m , 2h ) , 3.313.35 ( m , 1h ) , 3.573.70
( m , h3 , h6 , h6 , h2 , 4h ) , 3.75 ( app .
t , j =
6.0 hz , h5 , 1h ) , 3.833.84 ( m , h4 , 1h ) , 4.87 ( d , j = 3.5 hz , h1 , 1h ) , 5.185.19 ( m , 1h ) . c nmr
( 200 mhz , cdcl3 : cd3od ( 3:1 ) ) : 140.4 ,
121.9 , 97.1 ( c1 ) , 77.6 , 70.3 ( c3 ) , 69.9 ( c5 ) , 69.7 ( c4 ) , 68.9 ( c2 ) ,
61.6 ( c6 ) , 56.6 , 56.0 , 50.0 , 42.2 , 39.9 , 39.6 , 39.4 , 36.9 , 36.5 , 36.0 ,
35.7 , 31.7 , 31.6 , 28.1 , 27.9 , 27.6 , 24.1 , 23.6 , 22.6 , 22.3 , 20.9 ,
19.1 , 18.5 , 11.6 . hrms ( maldi - tof ) m / z : [ m + na ] calcd for c33h56o6na 571.3969 ; found 571.3968 . | ### Summary:
: a generalized synthesis of -d - cholesterylglycosides
has been achieved using one - pot per - o - trimethylsilyl
glycosyl iodide glycosidation . both cholesteryl -d - glucopyranoside ( cg ) and cholesteryl -d - galactopyranoside
were prepared in high yield .
these compounds were further esterified
using regioselective enzymatic acylation with tetradecanoyl vinyl
ester to afford 6-o - tetradecanoyl--d - cholesteryl glucopyranoside ( cag ) of helicobacter
pylori and the corresponding galactose analogue in 6678%
overall yields from free sugars .
the tandem step - economy sequence
provides novel analogues to facilitate glycolipidomic profiling . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the fibrinolytic enzyme in snake venom is defined as an enzyme that can hydrolyze fibrin to liquidize insoluble fibrin - rich clots but not form fibrin clots from fibrinogen .
the fibrinolytic enzymes are classified as serine protease and metalloprotease based on the structure of the active site and in -and -fibrinogenase based on the substrate specificity to -and -chain of fibrinogen .
the metalloproteases from snake venom which mostly require zinc at the active site are classified in classes pi to piv based on their multidomain organizations , which include a signal peptide , a prodomain , and a metalloprotease domain which is the structure of class pi and additional domains of disintegrin , cysteine - rich , and type c depending on the classes from pii to piv .
the enzymes act mainly as hemorrhagic factors , which exert their effects by degradation of basement membrane proteins , such as laminin , fibronectin , and collagen [ 3 , 4 ] .
the fibrin(ogen)olytic enzyme from snake venom has received attention as a medical agent to treat obstructive thrombosis and acute stroke by removing fibrinogen and fibrin from the blood .
thus , many kinds of the enzymes have been isolated and reported . however , the enzyme for clinical application should not cause hemorrhage .
fibrolase from agkistrodon contortrix contortrix(southern copperhead snake ) is a fibrinolytic enzyme which belongs to zinc metalloprotease and consists of 203 amino acid residues .
alfimeprase , an recombinant fibrolase , was used successfully in phase i and ii clinical trials to treat distal arterial occlusive disease , but target level was not attained , and so drug development was terminated .
gloydius blomhoffii , called salmusa in korea and known as mamushi in japan , is a venomous viper found in china , japan , and korea .
there are four subspecies : g. b. blomhoffii , g. b. brevicaudus , g. b. dubitatus , and g. b. siniticus .
choi detected fibrinolysis activities in the chromatographic fractions containing polypeptides of 59kda , 54kda , 46kda , 32kda , 18kda and 15kda isolated from the snake venom of gloydius blomhoffii siniticus .
the enzyme is a metalloprotease which is completely inhibited by ethylenediaminetetraacetic acid ( edta ) , ethyleneglycoltetraacetic acid ( egta ) and 1 , 10-phenanthroline and which hydrolyzes a -chain of fibrinogen initially and then slowly b -chain later .
choi and lee later reported isolation of a fibrin(ogen)olytic enzyme consisting of two disulfide - linked polypeptides with molecular weights of 18kda and 15kda from the same snake venom .
the fibrinolytic activity is inhibited completely by phenylmethanesulfonylfluoride ( pmsf ) and edta and partially by thiothreitol and cysteine , suggesting that the enzyme is a serine protease .
the characteristics of the enzyme were similar with those of brevinase isolated from the venom of the korean snake , agkistrodon blomhoffii brevicaudus .
the objectives of this study were to isolate the fibrinolytic enzyme with a molecular weight of 32kda from the snake venom of gloydius blomhoffii siniticus and to investigate its enzymatic characteristics and hemorrhagic activities .
ten g of lyophilized venom of gloydius blomhoffii siniticus from a chinese snake farm was dissolved in 100 ml of 50 mm tris - hcl , ph 7.6 and centrifuged at 10,000 g for 30 minutes .
the supernatant was injected into a column ( 5 cm 15 cm ) of q - sepharose ( ge , usa ) equlibrated with 50 mm tris - hcl , ph 7.6 .
the column was eluted with 600 ml of the tris buffer , and then with 600 ml of the tris buffer containing nacl with a linear concentration gradient from 0 m to 0.35 m. the column was then finally eluted with 200 ml of the tris buffer containing 0.35 m nacl .
the flow rate of eluant was 21 ml / hr . the volume of eluant was 7 ml / tube .
the fractions showing the fibrin hydrolyzing activity were collected , combined , and concentrated in dialysis tubing which was put into polyethylene glycol .
the concentrated solution was dialyzed in 50 mm tris - hcl , ph 7.6 , 0.15 m nacl and was then injected into a column ( 2.5 cm 117 cm ) of sephadex g-75 ( ge , usa ) .
the flow rate of eluant was 14 ml / hr and the volume of eluant was 7 ml / tube .
the fractions showing fibrin hydrolyzing activity were collected , combined , and dialyzed in 50 mm tris - hcl , ph 7.6 .
the solution was then injected into a column ( 2.5 cm 10 cm ) of deae - sepharose ( ge , usa ) .
the column was washed with 20 ml of 50 mm tris - hcl , ph 7.6 and was eluted with a linear concentration gradient from 0 m to 0.3 m nacl dissolved in the buffer .
all the chromatography procedures were performed at 4. the absorbance at 280 nm of appropriately diluted fractions from the chromatography was observed .
the fibrin - hydrolyzing activities of the fractions were observed by using the fibrin plate assays , as described by choi .
sodium dodecyl sulfate - polyacrylamide gel electrophoresis ( sds - page ) was performed according to the procedure described by laemmli .
the molecular weight markers ( bio - rad , usa ) for sds - page were phosphorylase b ( 97.4kda ) , serum albumin ( 66.2kda ) , ovalbumin ( 45.0kda ) , carbonic anhydrase ( 31.0kda ) , trypsin inhibitor ( 21.5kda ) , and lysozyme ( 14.4kda ) .
the sample buffer containing 2-mercaptoethanol was added to the sample and heated at 100 for 5 minutes .
the protein concentration was determined using bca protein assay reagent ( pierce , usa ) .
fibrinogen and gelatin were hydrolyzed using the isolated fibrinolytic enzyme and then subjected to sds - page .
an aliquot ( 200 l ) of 10 mg / ml protein in 50 mm tris- hcl ph 7.6 , 0.15 m nacl was mixed with 50 l of 2 g / ml fibrinolytic enzyme .
the samples ( 10 l ) which were taken from the mixture at 0.5 , 1 , 2 , 4 , and 6 hours were added to the sample buffer of sds - page , respectively .
the experiment to examine the effect of the isolated fibrinolytic enzyme on hemorrhage reaction beneath the back skins of mice was approved by the animal experiment ethics committee of sangji university ( approval document no .
an aliquot ( 0.1 ml ) of fibrinolytic enzyme in 50 mm tris - hcl , ph 7.6 , 0.15 m nacl at an appropriate concentration was injected subcutaneously into the back skin 6-week - old institute of cancer research ( icr ) mice of 6 week old ( daehan biolink , korea ) .
the mice were sacrificed using cervical dislocation after 6 hr and the skin around the injection was stripped to determine the diameter of the hemorrhage zone beneath the skin .
the hemorrhage areas were measured in duplicate by injecting the fibrinolytic enzyme into two mice , and the average was calculated .
the amino acid composition of the fibrinolytic enzyme was analyzed at the korea basic science institute .
the pitc - labeled amino acids were analyzed using a pico - tag column and the hplc instrument which consisted of a 510 hplc pump , a gradient controller , and a 2487 uv detector ( waters corporation , usa ) .
ten g of lyophilized venom of gloydius blomhoffii siniticus from a chinese snake farm was dissolved in 100 ml of 50 mm tris - hcl , ph 7.6 and centrifuged at 10,000 g for 30 minutes .
the supernatant was injected into a column ( 5 cm 15 cm ) of q - sepharose ( ge , usa ) equlibrated with 50 mm tris - hcl , ph 7.6 .
the column was eluted with 600 ml of the tris buffer , and then with 600 ml of the tris buffer containing nacl with a linear concentration gradient from 0 m to 0.35 m. the column was then finally eluted with 200 ml of the tris buffer containing 0.35 m nacl .
the flow rate of eluant was 21 ml / hr . the volume of eluant was 7 ml / tube .
the fractions showing the fibrin hydrolyzing activity were collected , combined , and concentrated in dialysis tubing which was put into polyethylene glycol .
the concentrated solution was dialyzed in 50 mm tris - hcl , ph 7.6 , 0.15 m nacl and was then injected into a column ( 2.5 cm 117 cm ) of sephadex g-75 ( ge , usa ) .
the flow rate of eluant was 14 ml / hr and the volume of eluant was 7 ml / tube .
the fractions showing fibrin hydrolyzing activity were collected , combined , and dialyzed in 50 mm tris - hcl , ph 7.6 .
the solution was then injected into a column ( 2.5 cm 10 cm ) of deae - sepharose ( ge , usa ) .
the column was washed with 20 ml of 50 mm tris - hcl , ph 7.6 and was eluted with a linear concentration gradient from 0 m to 0.3 m nacl dissolved in the buffer .
all the chromatography procedures were performed at 4. the absorbance at 280 nm of appropriately diluted fractions from the chromatography was observed .
the fibrin - hydrolyzing activities of the fractions were observed by using the fibrin plate assays , as described by choi .
sodium dodecyl sulfate - polyacrylamide gel electrophoresis ( sds - page ) was performed according to the procedure described by laemmli .
the molecular weight markers ( bio - rad , usa ) for sds - page were phosphorylase b ( 97.4kda ) , serum albumin ( 66.2kda ) , ovalbumin ( 45.0kda ) , carbonic anhydrase ( 31.0kda ) , trypsin inhibitor ( 21.5kda ) , and lysozyme ( 14.4kda ) .
the sample buffer containing 2-mercaptoethanol was added to the sample and heated at 100 for 5 minutes .
the protein concentration was determined using bca protein assay reagent ( pierce , usa ) .
fibrinogen and gelatin were hydrolyzed using the isolated fibrinolytic enzyme and then subjected to sds - page .
an aliquot ( 200 l ) of 10 mg / ml protein in 50 mm tris- hcl ph 7.6 , 0.15 m nacl was mixed with 50 l of 2 g / ml fibrinolytic enzyme .
the samples ( 10 l ) which were taken from the mixture at 0.5 , 1 , 2 , 4 , and 6 hours were added to the sample buffer of sds - page , respectively .
the experiment to examine the effect of the isolated fibrinolytic enzyme on hemorrhage reaction beneath the back skins of mice was approved by the animal experiment ethics committee of sangji university ( approval document no . 2102
an aliquot ( 0.1 ml ) of fibrinolytic enzyme in 50 mm tris - hcl , ph 7.6 , 0.15 m nacl at an appropriate concentration was injected subcutaneously into the back skin 6-week - old institute of cancer research ( icr ) mice of 6 week old ( daehan biolink , korea ) .
the mice were sacrificed using cervical dislocation after 6 hr and the skin around the injection was stripped to determine the diameter of the hemorrhage zone beneath the skin .
the hemorrhage areas were measured in duplicate by injecting the fibrinolytic enzyme into two mice , and the average was calculated .
the amino acid composition of the fibrinolytic enzyme was analyzed at the korea basic science institute .
the pitc - labeled amino acids were analyzed using a pico - tag column and the hplc instrument which consisted of a 510 hplc pump , a gradient controller , and a 2487 uv detector ( waters corporation , usa ) .
the fibrinolytic enzyme with a molecular weight of 32kda ( fe-32kda ) described by choi was obtained from g. b. siniticus venom by using several procedures of chromatography as follows ( figs , 1 , 2and3 ) . the combined sample of the fractions 102 - 107 from the q - sepharose column ( fig .
4 , lane c ) . the sample was then subjected to gel filtration chromatography on the sephadex g-75 column ( fig .
2 ) the combined sample of the fractions 39 - 44 contained the major polypeptide of fe-32kda and several minor polypeptides with the molecular weights of 15kda , 18kda , and 50kda ( fig .
the sample was then subjected to ion exchange chromatography on the deae - sepharose column .
the combined sample of the fractions 28 - 30 with high fibrinolytic activity contained only the polypeptide of fe-32kda ( fig .
the areas of the fibrinolytic zones in the fibrin plate assay were 0.79 cm , 0.64 cm , 0.50 cm , 0.38 cm at 0.5 mg/ ml , 0.4 mg / ml , 0.3 mg / ml , and 0.2 mg / ml of fe-32kda , respectively ( 1 - 4 in fig . 5 ) .
the fibrin plate assay showed that the minimum concentration of fe-32kda to form a fibrinolytic zone was ten times lower than that of fe-27kda and similar with that of fe-54kda [ 8 , 9 ] .
protease inhibitors were added to the solution containing fe-32kda ( 0.5 mg / ml ) in the fibrin plate assay .
the relative fibrinolysis was the ratio of the area of the enzyme treated with protease inhibitor to that of a control without treatment ( table1 ) .
table1shows that all of the chelate compounds , including edta , egta , 1 , 10-phenanthroline , inhibited fibrinolysis completely .
pmsf , a serine protease inhibitor , inhibited fibrinolysis partially and n - tosyl - l - lysinechloromethylketone ( tlck ) , an inhibitor of trypsin and trypsin - like protease , did not show any effect .
these results suggest that fe-32kda is a metalloprotease which has disulfide bonds necessary for the fibrinolytic activity .
the effects of metal ions on the fibrinolytic activity of fe- 32kda were determined ( table2 ) .
the concentration of metal ions added to fe-32kda ( 0.5mg / ml ) was 10 mm .
table2shows that fe and hg inhibited the fibrinolytic activity completely and that co inhibited it strongly .
ca , mn , and cu inhibited the fibirinolytic activity weakly and mg and cs had little effects on the fibrinolytic activity .
these results suggest that fe-32kda is a metalloproteinase which requires zn at the active site of the enzyme .
the zinc ion at the active site of the enzyme seems to have been partially lost during the purification procedures of the enzyme , and subsequent addition of zn in the fibrin plate assay seems to have increased the enzymatic activity .
fibrinogen ( 16 mg / ml ) was mixed with fe-32kda ( 1.6g / ml ) and incubated at 37 for a certain time .
the sample was subjected to sds - page to determine the fibrinogen hydrolysis pattern of fe-32kda ( fig .
the sds - page pattern showed that the intensity of -chain of fibrinogen decreased continuously throughout the incubation and was very low after 4 hours ( fig .
however , no change was noted for -chain and -chain of fibrinogen after 6 hours .
gelatin ( 16 mg / ml ) was mixed with fe- 32kda ( 1.6 g / ml ) and incubated at 37 .
the sample was subjected to sds - page to determine the fibrinogen hydrolysis pattern of fe-32kda ( fig .
the gelatin polypeptides with high molecular weights located beneath the border between the stacking gel and the separating gel decreased after 4 hours ( fig . 7 , lane 6 , 7 )
however , no further degradation to the polypeptides with molecular weight less than 50 kda was observed .
the hemorrhagic activity of fe-32kda was determined by injecting 100 l of fe-32kda at various concentrations subcutaneously into the shaved back skin of mice .
the mice were sacrificed after six hour and then the area of the hemorrhage zone ( fig .
8) formed beneath the skin was determined . when fe-32kda was administered to a mouse at the dosages of 20 g ,
10 g , 5 g , and 2 g , the areas of the hemorrhage zone were 1.8 cm , 2.2 cm , 1.4 cm , and 1.0 cm , respectively ( a - d in fig . 8)
the hemorrhagic activity of fe-32kda at the low dosage suggests that the enzyme is not appropriate for clinical treatment of obstructive thrombosis and acute stroke .
the enzyme contains cysteine residues which may be relevant to inactivation of the enzyme by cysteine and dithiothreitol ( table2 ) .
the contents of aspartic acid and leucine which are the major amino acid residues in fe- 32kda are 11.2% and 8.8% , respectively ( table3 ) .
three fibrinolytic enzymes , fe-54kda , fe-27kda , and fe-32kda , were isolated from the venom of g. b. siniticus .
however , both fe-54kda and fe-32kda were metalloproteases whose enzyme activities were inhibited by edta , egta , and 1 , 10-phenanthroline .
the fibrinolytic activities of fe-54kda and fe-32kda were promoted by calcium and zinc , respectively .
fe-54kda hydrolyzed most polypeptides of gelatin extensively into polypeptides with molecular weights less than 45kda . however , the hydrolysis of gelatin by fe-32kda produced polypeptides with molecular weights more than 50kda ( fig .
the areas of the fibrinolysis zones formed by fe-32kda were larger than those formed by fe-32kda .
brevilysin h1 from gloydius blomhoffii brevicaudus is a metalloprotease which hydrolyzes -chain of fibrinogen faster than -chain .
the enzyme has a molecular weight of 55kda in the reducing condition and 110 kda in the non - reducing condition of sds - page , consists of 420 amino acid residues , and is a piii - class metalloprotease . because fe-54kda and brevilysin h1 , which were isolated from the snakes of the same species , had similar molecular weights , they should be very similar molecules .
the molecular weights of fe-54kda suggests that the enzyme also belongs to the piii class .
terada and his colleagues studied the metalloproteases , such as brevilysin h6 [ 14 , 15 ] , brevilysin l4 [ 16 , 17 ] and brevilysin l6 , isolated from the venom of chinese mamushi , agkistrodon halys brevicaudus , which is classified currently in gloydius ussuriensis .
the molecular weight of brevilysin h6 is 60kda and zn is located at the active site of the enzyme .
the enzyme belongs to class piii which is composed of metalloprotease , disintegrin- like , and cysteine - rich domains and is degraded auto - catalytically into 29 kda and 45 kda fragments , both of which show no proteolytic activity .
these results show that fe-54kda is similar with brevilysin h6 in the aspects of the positive effects of ca on the fibrinolytic activity , the specificities to fibrinogen chains , and the molecular weights . the molecular weights of brevilysin l4 and l6 were 22kda and 21.5kda , respectively [ 16 , 17 ] .
the complete amino acid sequence of brevilysin l4 indicats that the enzyme is a pi class metalloprotease . the nucleotide sequence of a cdna clone encoding brevilysin l4 has revealed that the gene of brevilysin l4 encodes a pii - class metalloprotease , which undergo post - translational autoproteolysis to split into brevilysin l4 and disintegrin .
the molecular weight of fe-32kda suggests that the enzyme should belong to the pii class , which may also be split into a pi - class metalloprotease similar with non - hemorrhagic brevilysin l4 .
further studies are required to isolate a non - hemorrhagic brevilysin l4-like fibrinolytic enzyme from gloydius blomhoffii siniticus venom .
however , the hemorrhagic activity of fe-32kda in mice skin suggests that the enzyme is not appropriate for use as a clinical pharmacopuncture . | ### Summary:
: objectives : this study was undertaken to isolate a fibrinolytic enzyme from the snake venom of gloydius blomhoffii siniticus and to investigate its enzymatic characteristics and hemorrhagic activity as a potential pharmacopuncture agent.methods:the fibrinolytic enzyme was isolated by using chromatography , sodium dodecyl sulfate - polyacrylamide gel electrophoresis , and fibrin plate assay .
the characteristics of the enzyme were investigated using fibrin plate assay , protein hydrolysis analysis , and hemorrhage assay .
its amino acid composition was determined.results:the fibrinolytic enzyme with the molecular weight of 32kda ( fe-32kda ) from gloydius blomhoffii siniticus showed a fibrin hydrolysis zone at the concentration of 0.2 mg / ml in the fibrin plate assay .
the fibrin hydrolysis activity of the enzyme was inhibited completely by ethylenediaminetetraacetic acid ( edta ) , ethyleneglycoltetraacetic acid ( egta ) , and 1 , 10-phenanthroline , thiothreitol and cysteine , and partially by phenylmethanesulfonylfluoride ( pmsf ) .
metal ions such as fe2 + and hg2 + inhibited the fibrin hydrolysis completely , but zn2 + enhanced it . fe-32kda hydrolyzed -chain but did not hydrolyze -chain and -chain of fibrinogen .
high - molecular - weight polypeptides of gelatin were hydrolyzed partially into low - molecular - weight polypeptides , but the extent of hydrolysis was limited .
fe-32kda induced hemorrhage beneath back skin of mice at the dose of 2 g.conclusions:fe-32kda is a -fibrin(ogen)olytic metalloprotease that requires zn2 + for fibrinolytic activity and causes hemorrhage , suggesting that the enzyme is not appropriate for use as a clinical pharmacopuncture . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: surveillance data have often been used in the study of arboviral disease outbreaks ( 3,4 ) .
arbonet , a cooperative wnv surveillance program maintained by the centers for disease control and prevention and 48 states , five cities , and the district of columbia , collects surveillance data on a continuous basis .
these data include reports of wnv - infected mosquitoes , sentinel animals , dead birds , and ill humans and horses ( 5 ) . in 2001 , 328 counties reported a total of 7,333 wnv - infected dead birds ( range per county : 1350 ) .
the first wnv - infected dead bird was found on april 8 , and the last was found on december 26 .
sixty - six human cases of wnv disease were reported from 39 different counties in 10 states , including two outpatient west nile fever cases .
onset of illness was on july 13 for the first human case and december 7 for the last reported case .
of particular interest is the date that the first wnv - infected dead bird was found in a given county .
these dates ranged from the week ending april 14 to the week ending december 8 . in this retrospective cohort study , all u.s .
counties that reported dead wnv - infected birds were categorized on the basis of whether a wnv - infected bird was found early in the transmission season ( i.e. , before august 5 ) and whether at least one subsequent human disease case was reported from the county . a relative risk ( rr ) statistic was calculated as follows : the proportion of counties that reported human cases among the counties that found infected birds before august 5 was divided by the proportion of counties that reported human cases among the counties that did not find infected birds before august 5 .
of 93 counties that reported at least one wnv - infected bird before august 5 , 28 ( 30% ) subsequently reported a human wnv disease case in 2001 compared to 11 ( 4.7% ) of 235 counties that did not report an infected bird ( rr 6.43 , 95% confidence interval [ ci ] 3.34 to 12.38 ) . in other words , in 2001 , counties that reported a wnv - infected dead bird before august 5 were more than six times more likely than other counties to report a human wnv disease case ( figure 1 ) .
counties reporting avian deaths and human illness caused by west nile virus ( wnv ) , january 1december 31 , 2001 .
the color within the county indicates the date when the first avian death from wnv was reported in that county .
counties that report dead birds early in the year are more likely to report subsequent disease cases in humans . as figure 1 shows , the 2001 outbreak had two distinct geographic foci , the northeast and the southeast united states .
these areas were analyzed separately to determine if the correlation between wnv - positive birds and human cases was true in different ecologic regions .
the northeast region consisted of maryland , new jersey , pennsylvania , new york , connecticut , rhode island , and massachusetts .
rr statistics were significant for both regions ( northeast : rr 11.57 , 95% ci 3.58 to 47.99 ; southeast : rr 2.38 , 95% ci 0.89 to 6.39 ) .
recently , provisional totals for the 2002 wnv surveillance data have become available through arbonet . given the great increase in the geographic extent and the 50-fold increase in the number of human cases of wnv , we repeated this analysis by using the provisional data for 2002 to see if similar results would be obtained .
a great deal of variation in the reporting of wnv fever cases has occurred between states .
for this reason , only wnv meningitis and encephalitis cases were included in this analysis . in the provisional figures for 2002 ,
a total of 504 counties reported human cases of wnv meningoencephalitis , and 1,719 counties reported wnv - infected birds .
of 632 counties that reported at least one wnv - infected bird before august 4 , a total of 284 ( 45% ) subsequently reported a human wnv disease in 2002 compared to 220 ( 19% ) of 1,162 counties that did not report an infected bird ( rr 2.37 , 95% ci 2.05 to 2.75 ) . thus in 2002 , counties that reported a wnv - infected dead bird before august 4 were more than two times more likely than other counties to report a human case of wnv disease ( figure 2 ) .
counties reporting avian deaths and human meningitis / encephalitis caused by west nile virus ( wnv ) , january 1november 30 , 2002 .
the color within the county indicates the date when the first avian death from wnv was reported in that county .
counties that report dead birds early in the year are more likely to report subsequent disease cases in humans the early august date ( end of the 31st week of the year ) used for classifying the surveillance data was selected by empirical analysis of the wnv epidemiologic curves .
this date approximates the inflection point where the rapid increase in case reports occurs . using an earlier date for classifying the cases results in an increased value for the rr statistic but a decrease in sensitivity .
this type of analysis could possibly be refined by stratifying surveillance data by the number of birds and humans tested to compensate for variations in the intensity of the surveillance effort .
factors such as the size of the human population also may affect the number of dead birds sighted and the number of persons exposed to wnv - infected mosquitoes .
in addition , we are analyzing the data to determine if the risk for human illness is greater the earlier the positive bird ( or other indication of epizootic transmission ) is detected . however , the aim of this study was to see if a simple analysis of surveillance data could provide useful indicators of human disease risk .
the results of our analysis suggest that , in counties where an avian epizootic is present early in the transmission season , subsequent wnv disease in humans is more likely .
an early epizootic may indicate viral activity that has sufficient time to escalate to high levels before the end of the transmission season .
wnv - infected dead birds found in spring or early summer thus may be a warning for increased human risk for wn viral disease . | ### Summary:
: an analysis of 2001 and 2002 west nile virus ( wnv ) surveillance data shows that counties that report wnv - infected dead birds early in the transmission season are more likely to report subsequent wnv disease cases in humans than are counties that do not report early wnv - infected dead birds . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: complications due to trachoma are responsible for visual impairment in approximately 2.2 million people of whom 1.2 million are irreversibly blind.1 in egypt , three population - based surveys in the past 15 years have demonstrated that trachoma remains a public health problem in selected governorates.2345 in the governorates of menofiya , fayoum , and menia , the prevalence of trachomatous trichiasis ( tt ) defined as : inward turning of eyelashes ( or evidence of recent epilation ) due to scarring of the tarsal conjunctiva
ranges between 6.2% and 7.7% in adults aged 40 or older . in all three settings ,
females were about 1.7 times more likely to have tt compared to males . under - utilization of surgical services and poor quality
improving the uptake of surgery and other interventions are required in order to reduce the prevalence of trichiasis and the related complications specifically in these regions and in similar areas .
previous research in egypt indicated that multicomponent intervention is needed to overcome both community - based and system - based barriers to surgical uptake.6 community members were hesitant to seek any eye services including surgery .
in addition , tt patients , mostly females , received very limited social support to seek care .
these studies had also reported that modern surgical procedures had not been adopted , and most surgeons showed little interest in tt surgery , often imposing long waiting periods . in this study , we tested a multi - component intervention model including health education and door - to - door screenings combined with improvements in the infrastructure of the surgical service delivery designed to increase access to tt and acceptance of tt surgery , particularly by females .
a multi - component intervention trial was used to test the impact of the adoption of specific interventions to increase the uptake of trichiasis surgery .
the basic design included standardized pre- and post - intervention cross - sectional population - based surveys of trichiasis , surgical coverage of trichiasis , and barriers to utilizing eye care services in the target population .
the methods have been previously described.7 following the baseline survey , two villages were randomly selected for intervention ( intervention villages ) and two other villages were monitored without intervention ( nonintervention villages ) . at the time of the baseline survey , a situational analysis was performed at the two local governmental eye care hospitals to evaluate the surgical capacity , quality of care , capacity to absorb a potential increase in surgical volume , and number of surgeries performed over the previous 5 years . over the period of study ( 18 months ) ,
health education efforts were provided to the intervention villages . at the same time , educational efforts were directed at the government eye care providers at the district eye hospitals .
the second set of activities provided benefits to both intervention and nonintervention communities . a postintervention survey following the same guidelines ( different sample drawn )
the primary measurement of success was surgical coverage of trichiasis defined as : the proportion of people with trichiasis who had undergone surgery .
the selection criteria for the villages in the district were : population size 5000 inhabitants ; suspected high prevalence of blinding eye diseases ; available and accessible tertiary eye care facilities .
thirty - one ( 60.8% ) of the 51 district villages fulfilled the selection criteria .
two villages were randomly selected for intervention ( intervention villages ) and among the remaining villages , two other villages were randomly selected for comparison for nonintervention ( nonintervention villages ) .
the nonintervention villages were matched to the intervention villages for population and distance to surgical services for trichiasis .
within these four villages , households were randomly selected and within the selected households all residents 40 years were enumerated and enrolled .
a door - to - door eye examination of household members in each was conducted to collect data on blindness and the underlying causes , the presence of trichiasis and whether any of the tt patients had undergone a previous tt surgery .
trichiasis was defined as : one or more lashes touching the globe or evidence of epilation while trichiasis surgical coverage was defined as : the proportion of those with trichiasis ( or evidence of surgery ) who have had trichiasis surgery . demographic and socioeconomic characteristics were also collected .
advocacy sessions were held with political and health authorities , local nongovernmental organizations and community leaders to review the goals of the project .
consequently , two local community - based organizations agreed to join , and 38 community volunteers were enrolled .
the volunteers were trained in different aspects of health education , focused on managing barriers associated with transport , familial support for accessing surgery , and individual acceptance of undergoing surgery .
community health education was conducted door - to - door by the trained community volunteers using specifically designed material on trachoma and tt in terms of prevention and treatment , as well as availability , accessibility , and safety of the services .
door - to - door health education was accompanied by screening for individuals suspected to have trichiasis .
the eye care situation analysis indicated that surgical skills were inadequate ( use of non - who recommended trichiasis surgical procedures ) , that instruments and consumables for surgery were also inadequate , and that patients were routinely delayed from receiving the required interventions .
hence , the eye care capacity building included training in modern trichiasis surgical techniques , provision of trichiasis surgical sets , and education in how to better serve the needs of the local population .
the distance between the survey villages and the eye care facilities was , on average , about 20 km .
after completion of capacity building activities at the two local eye hospitals , a systematic program was created to facilitate access to services .
this program was based on a partnership between the eye care providers , the community - based organizations , and the trained volunteers .
the program included the creation of booking surgical lists ( to reduce patient waiting time , avoid exceeding the capacity of the hospitals , and improve efficiency of the eye care facility ) in addition to other logistical items .
assistance included enabling convenient transportation , accompaniment for the elderly and general interface with eye care providers .
the potential of contamination was mitigated by the enumerators , clinicians and volunteers in the nonintervention villages ( for monitoring ) as they were masked about the intervention .
data analysis was performed to evaluate the change in the prevalence of trichiasis , surgical coverage of trichiasis , as well as any changes in the self - reported barriers to uptake of services , preference to service provider , and patient satisfaction .
all data were collected on standard , pretested data collection forms , reviewed by the research team , then stored in a microsoft access 2007 ( microsoft corp . ,
, new york , ny , usa ) and statsdirect statistical software , version 2.7.2 ( statsdirect ltd . ,
this study adhered to the principles of the declaration of helsinki for research involving humans .
ethical approval was obtained from the university of british columbia , behavioral research ethics board , office of research services ( format version of august 23 , 2005 ) , in march 2006 , and from local health authorities in egypt .
the selection criteria for the villages in the district were : population size 5000 inhabitants ; suspected high prevalence of blinding eye diseases ; available and accessible tertiary eye care facilities .
thirty - one ( 60.8% ) of the 51 district villages fulfilled the selection criteria .
two villages were randomly selected for intervention ( intervention villages ) and among the remaining villages , two other villages were randomly selected for comparison for nonintervention ( nonintervention villages ) .
the nonintervention villages were matched to the intervention villages for population and distance to surgical services for trichiasis .
within these four villages , households were randomly selected and within the selected households all residents 40 years were enumerated and enrolled .
a door - to - door eye examination of household members in each was conducted to collect data on blindness and the underlying causes , the presence of trichiasis and whether any of the tt patients had undergone a previous tt surgery .
trichiasis was defined as : one or more lashes touching the globe or evidence of epilation while trichiasis surgical coverage was defined as : the proportion of those with trichiasis ( or evidence of surgery ) who have had trichiasis surgery .
advocacy sessions were held with political and health authorities , local nongovernmental organizations and community leaders to review the goals of the project .
consequently , two local community - based organizations agreed to join , and 38 community volunteers were enrolled .
the volunteers were trained in different aspects of health education , focused on managing barriers associated with transport , familial support for accessing surgery , and individual acceptance of undergoing surgery .
community health education was conducted door - to - door by the trained community volunteers using specifically designed material on trachoma and tt in terms of prevention and treatment , as well as availability , accessibility , and safety of the services .
door - to - door health education was accompanied by screening for individuals suspected to have trichiasis .
the eye care situation analysis indicated that surgical skills were inadequate ( use of non - who recommended trichiasis surgical procedures ) , that instruments and consumables for surgery were also inadequate , and that patients were routinely delayed from receiving the required interventions .
hence , the eye care capacity building included training in modern trichiasis surgical techniques , provision of trichiasis surgical sets , and education in how to better serve the needs of the local population .
the distance between the survey villages and the eye care facilities was , on average , about 20 km .
after completion of capacity building activities at the two local eye hospitals , a systematic program was created to facilitate access to services . this program was based on a partnership between the eye care providers , the community - based organizations , and the trained volunteers .
the program included the creation of booking surgical lists ( to reduce patient waiting time , avoid exceeding the capacity of the hospitals , and improve efficiency of the eye care facility ) in addition to other logistical items .
assistance included enabling convenient transportation , accompaniment for the elderly and general interface with eye care providers .
the potential of contamination was mitigated by the enumerators , clinicians and volunteers in the nonintervention villages ( for monitoring ) as they were masked about the intervention .
data analysis was performed to evaluate the change in the prevalence of trichiasis , surgical coverage of trichiasis , as well as any changes in the self - reported barriers to uptake of services , preference to service provider , and patient satisfaction .
all data were collected on standard , pretested data collection forms , reviewed by the research team , then stored in a microsoft access 2007 ( microsoft corp . ,
, new york , ny , usa ) and statsdirect statistical software , version 2.7.2 ( statsdirect ltd . ,
this study adhered to the principles of the declaration of helsinki for research involving humans .
ethical approval was obtained from the university of british columbia , behavioral research ethics board , office of research services ( format version of august 23 , 2005 ) , in march 2006 , and from local health authorities in egypt .
a total of 272 households were visited in the 4 villages . during the baseline survey ,
525 people were enrolled who were aged 40 years or older . among the 75 unexamined subjects ,
53 ( 70.7% ) were not available after repeated visits , 15 ( 20% ) could not be assessed ( 4 due to age and illness ) , and 7 ( 9.3% ) refused to be examined ) . at baseline , the prevalence of trichiasis and the uptake of trichiasis surgery were very similar in both intervention and nonintervention villages [ table 1 ] . among the 51 trichiasis cases
, there were 40 ( 78.4% ) females and they had a lower trichiasis surgical coverage ( 8/48 ; 16.7% ) compared to males ( 38.9% ) .
overall , the prevalence of trachomatous corneal opacity was 3% , accounting for 12% of all blindness ( defined as presenting vision < 3/60 in the better eye ) . among the 15 eyes that had undergone previous trichiasis surgery ,
baseline prevalence of trichiasis during the 3 months of initial intervention , the trained volunteers visited 2,354 households and identified 97 individuals with trichiasis and referred all of them for surgery . among these individuals , 66 ( 68% ) were assisted to obtain trichiasis surgery [ table 2 ] .
uptake of trichiasis surgery in intervention community patients in the postintervention survey , 518 individuals were examined in 231 households of the same villages . in intervention villages ,
the prevalence of tt significantly decreased from 9.4% ( 5.7% males , 11.8% females ) in the preintervention assessment to 3.8% ( 1.9% males , 5.1% females ) ( p = 0.013 ) in the postintervention assessment . in nonintervention villages
, there was a slight , decrease in tt from 10.1% ( 3.1% males , 14.4% females ) to 8.2% ( 3% males , 11.5% females ) , respectively ( p = 0580 ) .
the prevalence of trichiasis was significantly lower , and the surgical coverage was significantly higher in the intervention villages compared to the nonintervention villages ( 3.88.2% and 6814.7% for intervention and nonintervention villages , respectively ) [ table 3 ] .
prevalence of trichiasis and trichiasis surgical coverage pre- and post - intervention among the 51 subjects identified as having trichiasis at baseline who had never sought eye care services ; 21 ( 41.2% ) did not feel that it was a problem ; 11 ( 21.6% ) underwent epilation instead 17 ( 33.3% ) were aware of having tt but for different reasons did not seek eye care ; and 7 ( 13.7% ) were advised to seek surgery , however , they did not comply .
the major barriers to seeking surgical services in the intervention villages post - intervention were : feeling no serious problem ( 19 ; 17.3% ) , fear of surgery ( 14 ; 12.7% ) , inability to cover costs ( 14 ; 12.7% ) , and fear of the outcome of surgery ( 13 ; 11.8% ) [ table 4 ] .
barriers to utilization of eye care service among tt patients prior to intervention at baseline , many of the comments can be summarized as being related to how patients are treated at government hospitals : fear of bad treatment at the hospital ; since , i am a poor patient and the only available option to me is the free governmental service , then i will be badly treated and will receive low - quality service . prior to intervention , trichiasis patients reported that their first choice for eye care was private practice ( 41.2% ) while at the postintervention assessment , the first choice for eye care was the local government hospital ( 48.6% ) .
in addition , the hospital records on trichiasis surgery show an increase in the annual number of trichiasis surgeries from 235 surgeries in 2006 to 592 surgeries in 2008 [ figure 1 ] .
pattern of increase in uptake of trachomatous trichiasis comparing program impact years to the previous 5 years
current global efforts to reduce the prevalence of trichiasis ( and thus , reduce the risk of vision loss ) are inadequate if the who target of eliminating blinding trachoma by the year 2020 is to be reached.1 there is no one single solution to improving service uptake and understanding both the surgical services ( limitations and capacities ) and the population requiring the services .
these issues are crucial for any endeavor to develop a practical and successful intervention model.8 in this study , we presented a model that adopted three major components : community health education , capacity building of local eye care providers , and the interface between the community and eye care providers .
this approach was used to reduce barriers to utilization of the service and improve the quality of care .
however , our findings suggest that , in combination , they can significantly increase the pattern of service utilization.9 although these findings may not be surprising to many within the trachoma and eye care community , our study may be the first to simultaneously test the combination of these components.10 the 2.5-fold reduction in trichiasis and the 3.4-fold increase in trichiasis surgical coverage in the intervention villages ( alongside minimal change in the nonintervention villages ) should be considered in the context that increasing the quality of care at the local eye care facilities was potentially beneficial to people living in nonintervention villages as well .
however , there was continually lower utilization of trichiasis surgery among females compared to males .
this is consistent with previous research in egypt and similar countries in the region.61112 however , the global perspective is variable.1314 undertaking research in egypt has several implications .
first , although egypt is listed as a trachoma endemic country , there has been no recent mapping of trachoma on the national level .
consequently , there are no interventions to reduce trachoma , and unless there is a concerted effort to map and intervene , it is possible that egypt could fail to reach the global goal of elimination of blinding trachoma by the year 2020 .
second , the findings suggest , certainly in egypt and likely elsewhere , that well - designed , systematic efforts to address trichiasis have a high likelihood of success.151617 third , the active engagement of community - based organizations and volunteers in this rural setting is indicative of the tremendous potential to harness the local capacity to mobilize the population .
that said , mobilization of the population without actively addressing weaknesses in the health system will likely threaten any success . in our study
, we could not assess surgical outcome of referred cases ; previous findings in egypt and elsewhere in the region have suggested that poor outcome ( post - trichiasis surgery ) is a serious problem requiring sustained effort to address.181920 with the introduction of interventions , it comes as no surprise that the barriers to utilizing trichiasis surgery in this setting have significantly changed . as the direct cost of trichiasis surgery is relatively small , the change in barriers while multi - factorial in nature generally focused on perceptions of how they will be treated at the hospital .
ultimately , improving satisfaction with the delivery of services changes the attitude of the population toward such services .
eventually , this will improve and maintain the sustainability of services and the success of the program .
there were a number of challenges in undertaking this research including working with government facilities and difficulties in instituting new surgical and management protocols , providing and evaluating a hands - on training program for ophthalmic surgery teams , improving weak registry systems , and changing attitudes of those who need the services ( mainly elderly females ) .
although we can not conclusively attribute the increase in service uptake to the intervention program , the lack of significant change in service uptake in the nonintervention villages suggests that the program was instrumental in achieving the desired changes .
generalizing this study finding to all trachoma endemic settings should consider regional and population variations .
however , the findings of this study suggest that investment in community - based initiatives and provider - based capacity building may lead to greater utilization and , eventually , lower the risk of vision loss due to trachoma .
finally , the persistent gap in utilization of services between social genders needs more qualitative research to refine the community - based initiatives .
| ### Summary:
: purpose : the purpose of this study was to measure the impact of a community - based intervention on uptake of trichiasis surgery in southern egypt.methods:four villages where trachoma is endemic were randomly selected in the samalout district , egypt .
two villages were selected for intervention ( intervention villages ) and two matched villages for nonintervention ( nonintervention villages ) .
the intervention model provided community information sessions , door - to - door health education , screening , and improvements in the clinical capacity of eye care providers .
the intervention was evaluated through two pre- and post - intervention community - based surveys that included the prevalence of trachoma and the utilization of eye care services at local hospitals .
all patients with trichiasis answered a questionnaire regarding surgical utilization and barriers.results:in the baseline survey , the trachomatous trichiasis ( tt ) surgical coverage was 22.7% ( 38.9% males , 16.7% females ) in all villages . following the intervention ,
the tt surgical coverage increased to 68% in villages that received the intervention ( 81.5% males , 60% females ) .
nonintervention villages had a tt surgical coverage of 26.1% ( 37.5% males , 20% females ) . in the intervention villages ,
the prevalence of tt significantly decreased from 9.4% ( 5.7% males , 11.8% females ) to 3.8% ( 1.9% males , 5.1% females ) ( p = 0.013 ) , in 2008 . in nonintervention villages
, there was a slight , but insignificant decrease in tt from 10.1% ( 3.1% males , 14.4% females ) to 8.2% ( 3% males , 11.5% females ) ( p = 0.580 ) .
the major barriers to uptake of tt surgical services were : feeling no problem
( 17.3% ) , fear of surgery
( 12.7% ) and cost
( 12.7%).conclusion : a community - based eye health education program with door - to - door screening significantly increased the uptake of tt surgical services .
although improvements to the delivery of surgical service are essential , they did not lead to any significant improvements in the nonintervention villages . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: low thyroid function irrespective of age has been found to have detrimental effect on cognitive functions because hypothyroidism prevents the brain from adequately sustaining the energy ( glucose)-consuming processes needed for neurotransmission , memory and other higher brain functions .
hypothyroidism is associated with significant neurocognitive deficits involving attention and concentration , memory , perceptual function , defective language , executive functions , development of a range of intellectual , disorientation in space and time , loss of autonomy , emotional depersonalization and other mental defects .
hypothyroidism in non - demented older adults is associated with impairments in learning , word fluency , visual - spatial abilities , some aspect of attention , visual scanning and motor speed .
cognitive functions can be assessed by evoked potential e.g. , p300 wave of event related potential ( erp ) .
some researchers have found that subclinical hypothyroidism is associated with changes in mood and cognitive functioning while other were of the opinion that no correlation exists between these two .
the present study was conducted in the department of physiology in collaboration with the department of medicine , pgims , rohtak , india .
it included 75 patients of newly diagnosed clinical and subclinical hypothyroidism patients attending endocrinology clinic and 75 healthy age and sex matched euthyroid controls [ table 1 ] .
the subjects were divided into three groups : height , weight matching along with hormone level group i : comprised of age and sex matched 75 healthy euthyroid subjects group ii : comprised of 75 newly diagnosed patients of subclinical hypothyroidism of either sex below the age of 50 years group iii : comprised of 75 newly diagnosed patients of clinical hypothyroidism of either sex below the age of 50 years .
hypothyroidism was diagnosed by increased thyroid stimulating hormone ( tsh ) and decreased thyroid hormone level . to avoid the effect of aging over cognition ,
we have included subjects below 50 years of age . for subclinical hypothyroidism tsh level >
5.1miu / l and t4 57.9 nmol / l . for clinical hypothyroidism tsh level >
patients with any other major medical disorder which can affect cognitive function , i.e. diabetes mellitus , anaemia , hypertension , chronic obstructive pulmonary disease , acute or chronic liver and kidney diseasehistory of drug abuse including alcoholismneurological or psychiatric illnessaltered sensoriumpatients who do nt co - operate during the study period .
patients with any other major medical disorder which can affect cognitive function , i.e. diabetes mellitus , anaemia , hypertension , chronic obstructive pulmonary disease , acute or chronic liver and kidney disease history of drug abuse including alcoholism neurological or psychiatric illness patients who do nt co - operate during the study period .
the volume conducted evoked responses were picked up from scalp by using disc type of ag / agcl2 electrodes .
two reference electrodes was attached to left and right mastoid , designated as a1 and a2 respectively , one active electrode on vertex labeled as cz and one as ground electrode to forehead termed as fpz .
recommended montages for erp p300 were : channel 1 : cz -a1 , channel 2 : cz -a2 and ground : fpz .
target or rare tone and non target or frequent tone of 70 db was applied on both ears simultaneously through headphones applied to ears of subject .
rare tone stimuli were given in 20% and frequent tone stimuli in 80% frequency in random .
the signals were picked by electrodes and were filtered , amplified , averaged , displayed on the screen of rms emg ep mk2 and recorded .
all the data gathered were tabulated and were analyzed using spss 14 version . for analysis anova
hypothyroidism was diagnosed by increased thyroid stimulating hormone ( tsh ) and decreased thyroid hormone level . to avoid the effect of aging over cognition , we have included subjects below 50 years of age . for subclinical hypothyroidism tsh level >
5.1miu / l and t4 57.9 nmol / l . for clinical hypothyroidism tsh level >
patients with any other major medical disorder which can affect cognitive function , i.e. diabetes mellitus , anaemia , hypertension , chronic obstructive pulmonary disease , acute or chronic liver and kidney diseasehistory of drug abuse including alcoholismneurological or psychiatric illnessaltered sensoriumpatients who do nt co - operate during the study period .
patients with any other major medical disorder which can affect cognitive function , i.e. diabetes
mellitus , anaemia , hypertension , chronic obstructive pulmonary disease , acute or chronic liver and kidney disease history of drug abuse including alcoholism neurological or psychiatric illness patients who do nt co - operate during the study period .
the volume conducted evoked responses were picked up from scalp by using disc type of ag / agcl2 electrodes .
two reference electrodes was attached to left and right mastoid , designated as a1 and a2 respectively , one active electrode on vertex labeled as cz and one as ground electrode to forehead termed as fpz .
recommended montages for erp p300 were : channel 1 : cz -a1 , channel 2 : cz -a2 and ground : fpz .
target or rare tone and non target or frequent tone of 70 db was applied on both ears simultaneously through headphones applied to ears of subject .
rare tone stimuli were given in 20% and frequent tone stimuli in 80% frequency in random .
the signals were picked by electrodes and were filtered , amplified , averaged , displayed on the screen of rms emg ep mk2 and recorded .
all the data gathered were tabulated and were analyzed using spss 14 version . for analysis anova
the tsh was significantly higher ( p < 0.001 ) in clinical hypothyroid patients compared with subclinical and controls . while t4 was significantly lower ( p < 0.001 ) in clinical hypothyroid patients when compared with subclinical and controls as shown in table 1 .
on comparison between subclinical and control , tsh was significantly higher ( p < 0.001 ) and t4 was significantly lower ( p < 0.05 ) in subclinical group . height and weight were comparable amongst the three groups .
table 2 shows that newly diagnosed clinical hypothyroid patients showed a significant increase in p300 latency compared to control ( p < 0.01 ) and subclinical cases ( p < 0.05 ) while there was no significant difference between the p300 latency of subclinical cases and control group .
also , there was no significant difference in p300 amplitude among the three groups [ figures 13 ] .
comparison of erp p300 values of subclinical clinical and control cases comparison of p300 latency and amplitude between control ( group i ) and newly diagnosed subclinical hypothyroid patients ( group ii ) comparison of p300 latency and amplitude between control ( group i ) and newly diagnosed clinical hypothyroid patients ( group iii ) comparison of p300 latency and amplitude between newly diagnosed subclinical ( group ii ) and clinical ( group iii ) hypothyroid patients table 3 shows that the correlation coefficient between p300 latency and t4 was negative ( 0.546 ) and statistically significant , while with tsh , it was positive ( 0.267 ) , though statistically non - significant .
the correlation coefficient between p300 amplitude and t4 was positive ( 0.042 ) and with tsh , it was also positive ( 0.159 ) , but none was statistically significant .
correlation of hormone level with p300 latency and amplitude in group ii table 4 shows that the correlation coefficient between p300 latency and tsh was positively correlated ( 0.414 ) and statistically significant , while with t4 , it was negatively correlated ( 0.072 ) and non - significant .
the correlation coefficient between p300 amplitude and t4 was positive ( 0.196 ) , while with tsh , it was negative ( 0.013 ) , though both were statistically non - significant .
thyroid dysfunction is related to nervous system disorder involving gaba as reported by clinical studies .
studies done recently shows that the cases previously considered asymptomatic may be having many non specific subjective features . in these patients there may be fine but subtle difference from euthyroid .
the transition from normal euthyroid to hypothyroid is continuous and hence while assessing a case both the degree and duration of the case has to be considered .
subclinical hypothyroidism is marked by increase in serum tsh level while thyroid hormone level in serum is normal .
one result of this which is postulated is there is an alteration on cognitive function and mood .
our result in table 2 shows that there is significant difference in p300 latency between clinical and subclinical cases while there is highly significant difference between clinical and controls .
our finding is supported by studies made by tutuncu et al . who reported that there is delay of p300 latency in both mild and severe case of hypothyroidism .
also derived the same finding when studying the effect of hyper and hypo thyroidism on p300 latency . on the contrary studies by osterweil et al
we further went ahead to find out a correlation between t4 , tsh and p300 latency and amplitude which showed significant negative correlation in clinical cases when t4 was compared with p 300 latency while the rest have been non significant as shown in tables 3 and 4 .
p300 latency in case of newly diagnosed clinical hypothyroid patients was significantly increased in comparison to newly diagnosed subclinical cases and control groups . | ### Summary:
: introduction : hypothyroidism is associated with significant neurocognitive deficits because hypothyroidism prevents the brain from adequately sustaining the energy consuming processes needed for neurotransmission , memory , and other higher brain functions .
hence , the study was done to assess the cognitive functions of newly diagnosed subclinical and clinical hypothyroid patients by evoked response potential p300.materials and methods:75 patients each of newly diagnosed subclinical and clinical hypothyroid patients attending endocrinology clinic and 75 healthy age and sex matched euthyroid controls were considered for the study .
p300 was recorded with record medicare system polyrite , chandigarh using auditory oddball paradigm .
the data was analyzed using anova followed by post tukey 's test.results:newly diagnosed clinical hypothyroid patients showed a significant increase in p300 latency compared to control ( p < 0.05 ) and subclinical cases ( p < 0.01 ) while there was no significant difference between the p300 latency of subclinical cases and control group . also , there was no significant difference in p300 amplitude among the three groups.conclusion:p300 latency in case of newly diagnosed hypothyroid clinical cases is significantly increased compared to newly diagnosed subclinical cases and control . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: adolescent suicide is a growing concern , being a major cause of death among adolescents .
data from the united states shows that among youths aged 10 to 17 years , the annual suicide rate is three in 100,000 ; in youth aged between 17 to 19 years , this rate increases to 1012 in 100,000.1 portuguese data reveals that suicide rates in youth aged between 15 and 24 years have dropped from four in 100,000 in 2003 to 24 in 100,000 in 2006.2 suicide is still a major public health issue .
nonetheless , the numbers could be even higher since studies indicate that the so - called undetermined death rates may contain a substantial number of hidden suicides,3 which could be true because the portuguese statistics show a lower suicide rate compared to the european average.4 there are great variations in suicide rates according to geographic and cultural variables .
durkheim s classic work in the field of sociology claims that the tendencies of the whole social body , by affecting individuals , cause them to commit suicide .
the private experiences usually thought to be the proximate causes of suicide have only the influence borrowed from the victim s moral predisposition , itself and echo of the moral state of society.5 this is an important consideration that justifies , at least in part , the variation in suicide rates across societies .
suicide in adolescents has been associated with many factors and a previous suicide attempt ( deliberate self - harm [ dsh ] with suicidal intent ) is among the most significant predictive factors for future suicidal behavior.6 studies have associated dsh without suicidal intent ( or parasuicide ) with the risk of completed suicide,7,8 showing that this type of behavior is as serious as attempted suicide , although likely to be underestimated.9 there are some differences in the literature regarding the definition of self - harm.10 for the purposes of this study we applied the definition used in the child and adolescent self - harm in europe ( case ) study.11 the criteria for self - harm is an act with a nonfatal outcome in which an individual deliberately did one or more of the following : initiated behavior ( for example , self - cutting , jumping from a height ) , which they intended to cause self - harm ; ingested a substance in excess of the prescribed or generally recognized therapeutic dose ; ingested a recreational or illicit drug that was an act that the person regarded as self - harm or ; ingested a noningestible substance or object .
this definition includes both parasuicide ( or dsh without suicidal intent , a designation preferred by some authors)8 and suicide attempts ( or dsh with suicidal intent ) .
we chose this definition because it emerged from a consensus within a large international work group that recently studied a large sample of adolescents who self - harm.11 according to the latter study , 8.9% of females and 2.6% of males overall reported an episode of dsh in the past year , and 13.5% and 4.3% reported an episode sometime in their lifetime , respectively .
the most frequent forms of dhs were self - mutilation and overdose.11 dsh is very relevant in adolescent mental health and is associated in approximately 87% of cases with a diagnostic and statistical manual of mental disorders ( dsm - iv ) axis 1 diagnosis.8 symptoms of depression / anxiety and delinquent / aggressive behavior were associated with self - harming behavior in both adolescent girls and boys.12 dsh was associated with varying degrees of suicidal intent.13 studies described that social background factors like problems with work , relationships with family , partners , and friends are most likely to contribute to dsh episodes.13,14 a large community sample study verified that adolescents with dsh were likely to feel the need for help but not try to get any .
they were less able to talk to family members and teachers and had fewer categories of people who they were able to talk with .
they differed from other adolescents in terms of coping strategies they reported employing when faced with difficulties , showing less focus on problems and more avoidance behavior.15 this association can partially explain why social background factors relate with dsh .
a previous study from our group analyzed the profile of the users of our youth suicide consultation who engaged in dsh , showing that they were predominantly girls aged between 15 and 21 years with vulnerabilities in socioaffective skills , family and love relationships , and who perceive their individual and familial difficulties as intolerable and catastrophic .
their preferred coping strategies were avoidance and elimination.16 the aim of the present study is to further describe the characteristic clinical features of adolescents with dsh ( a high risk group for completed suicide ) according to our local context ( lisbon , portugal ) . the other aim is to do so without the use of specific assessment scales , using easily available information from the clinical setting .
we decided to do this based on the fact that , although this practice goes against evidence - based medicine , studies show that the majority of psychiatrists do not use outcomes measures in their day - to - day practice.17,18 another potential advantage is that clinical interview data can also provide a richness of detail and contextual information that standardized assessment scales may miss .
a case control study was constructed from a sample of 100 adolescents ( aged 12 to 21 years ) .
the sample originated from the adolescent psychiatry and youth suicide consultations of the hospital de santa maria psychiatry department in lisbon , portugal .
the adolescent psychiatry consultation is general , accepting all psychiatric referral motives , takes place once a week and has a wait - list of about one month . on the other hand
the youth suicide consultation , has no wait - list , takes place every weekday , and only accepts referrals related to suicide ideation or self - harm behavior .
the case files of adolescents followed in 2007 and 2008 were initially screened for any episodes of dsh according to the case study definition,11 then divided into two groups ( with and without dsh ) .
afterwards they were randomly selected ( approximately 400 from the total cases of adolescents followed in 20072008 were chosen using a randomizing function ) until a total of 50 subjects were reached for each group .
all the case files were reviewed and the missing data was completed through clinical interviews .
demographic , psychosocial , and psychopathological data were collected through a checklist that our group uses in both consultations .
all the variables were selected according to two relevant criteria : readiness of availability ( information that is normally collected during clinical interview in adolescents , without the use of any particular screening instrument ) and high frequency of data ( information that is usually referred by patients in our consultations ) .
the demographic data collected included age , gender , professional status ( currently studying or working ) , education ( primary education , defined as the completion of nine years of school ; secondary education , defined as the completion of 12 years of school or ; college , defined as completed college education ) , and family type ( nuclear family or other ) .
the psychosocial data included : main referral motive ( collected in four categories : suicidal ideation or dsh ; behavior problems ; school difficulties or ; other psychopathological problems ) ; origin of the referral ; reported psychosocial difficulties ( collected in five categories , which could co - exist : family conflicts ; affective conflicts ; peer conflicts ; school difficulties and professional difficulties ) ; existence of previous follow - up attempts ; therapeutic goals of the present follow - up ( collected in six categories , which could be combined : optimization and change of family relations ; of affective relations ; of peer relations ; of school situation ; of professional situation and/or ; of personality traits ) .
the psychopathological data included : main psychopathological syndrome , ( according to case file data and collected in four categories : depression ; anxiety ; disruptive behavior or other syndromes ) ; the existence of suicidal ideation and deliberate self - harm behavior at the time of the first consultation .
a comparison between the dsh and non - dsh groups was performed , in an attempt to determine statistical differences between the referred variables . because no assessment scales were used , most variables were nominal in nature and thus the main statistical tests used were the chi - squared test and fisher s exact test . in determining the differences in average reported psychosocial difficulties and average therapeutic goals in present
the authors confirm that all the research meets the ethical guidelines and legal requirements of portugal .
data was incomplete in two adolescents from the dhs group who were unable to complete their clinical interview and therefore were not included in this analysis . in the dsh group , 21 subjects committed dsh with suicidal intent ( suicide attempts ) .
twenty - seven subjects had dsh without suicidal intent ( parasuicides ) . the most common forms of dsh were overdose and self - mutilation .
there were no statistical differences in the demographic variables between the two groups ( table 1 ) .
with regard to the referral motive , we found a significant statistical association between suicide ideation or previous dsh as referral motive ( chi - squared test , p < 0.001 ) . because most referrals on the dsh group were motivated by both suicidal ideation and previous dsh ,
it was impossible to determine the main reason so we decided to merge them ( in the control group there were no referrals motivated by dsh ) . nevertheless , 10 out of 48 of the adolescents of our sample ( approximately 21% of subjects ) with a history of dsh were referred for other reasons .
the main referral motive of the control group was other psychopathological problems , which were mostly problems of depression ( without suicide ideation or dsh ) , but motives also included anxiety , psychosis , and drug abuse . in regard to the origin of the referral
, we concluded that 50% of the individuals in the dsh group were referred after a visit to the emergency department .
there was a statistically significant difference between the two main groups in this matter ( fisher s exact test , p < 0.001 ) .
the other significant difference we report is the relative low number of dsh cases referred from primary care ( fisher s exact test , p = 0.004 ) .
moreover , there was no clear statistical difference between the two groups regarding the main psychopathological syndrome diagnosed at present follow - up , although there was a nonsignificant ( chi - squared test , p = 0.059 ) trend in diagnoses of depression in the dsh group .
table 2 shows the complete data on referral variables , main psychopathological syndrome , and previous follow - up attempts .
when adolescents were directly asked about present suicidal ideation at the time of the first consultation , 33 subjects of the dsh group gave a positive answer versus only nine positive answers in the non - dsh group .
there was a statistically significant difference between the two groups ( chi - squared test , p < 0.001 ) .
nevertheless , 15 adolescents ( 31% of the subjects ) with previous dsh denied the presence of suicidal thoughts at the time of the first interview .
there was also a significant difference in the average number of psychosocial difficulties reported between the two groups . in the group with dsh ,
the mean reported number was 2.00 ( standard deviation [ sd ] = 1.23 ) versus 1.54 ( sd = 0.94 ) in the control group ( student s t - test , 95% confidence interval [ ci ] ; p = 0.04 ) .
for both groups , the most frequently reported difficulties were family and affective conflicts . in regard to the therapeutic goals of the present follow - up , the only statistically significant differences we report were on change in family relations
( chi - squared test , p = 0.002 ) and change in school situation ( chi - squared test , p = 0.001 ) , as the group with dsh showed less interest in these goals .
additionally , a significant difference was seen in the average number of therapeutic goals in the present follow - up between both groups . in the dsh group ,
the mean was 1.44 ( sd = 1.22 ) versus 2.10 ( sd = 1.45 ) in the control group ( student s t - test , 95% ci ; p = 0.02 ) .
importantly , for the dsh group adolescents , the most frequently referred features that they wished to change were personality traits .
by contrast , subjects from the control group mainly sought changes in family relations and school situation .
the complete data on the reported psychosocial difficulties and therapeutic goals for the present follow - up are summarized in table 3 .
as we previously stated , the main goal of our study was to know more about the characteristic clinical features of the adolescents with dsh in our consultations .
we tried to achieve this goal through the use of easily accessible clinical data . as we reported earlier ,
this is an important factor in case - control studies and reflects a good randomization of selected cases .
as would be expected , there was a statistically significant association between suicidal ideation or previous dsh as main referral motive .
nevertheless , 21% of the adolescents with a history of dsh were referred to our consultation for other reasons . in our opinion
, this finding could have one of two meanings : one of them is that adolescents with dsh are often underrecognized , an idea supported by clark , who investigated adolescents in primary care settings and found that 83% of adolescent patients with a history of attempted suicide were not recognized as suicidal by their primary care physician.19 another possible meaning is that depression , anxiety disorders,20 behavior problems,21 and school difficulties22 can be warning signs for suicide risk in adolescents , and should prompt an assessment of that same risk by a qualified health professional .
the control group was clearly different ; the referral was mainly motivated by depression ( without dsh ) , anxiety disorders , and behavior problems ( externalizing disorders ) , which is consistent with the literature regarding adolescent psychopathology.23 interestingly , we observed that 50% of the individuals in the dsh group were referred after a visit to the emergency department , which is consistent with the findings that suicidal ideation or dsh is frequently disclosed by patients in emergency settings ( although they not always turn out to be referenced to mental health services).24 furthermore , we acknowledge having had a very low number of referrals from primary care physicians , which can reflect an under recognition of suicide risk , as we discussed above . another possible explanation for this fact is related to the setting of our consultations , which is mainly hospital - based .
another interesting result documented was the fact that depression was not significantly associated with the case group , although there was a trend in that direction .
our opinion is that the power of the study was probably insufficient to show that difference , and that a larger sample ( or the use of specific depression assessment scales ) would be needed for it to emerge , as depression is a well established risk factor for dsh or completed suicide.21 additionally , we found that previous follow - up attempts were highly associated to the dsh group .
studies indicate that psychiatric treatment of suicidal youths is often difficult and that noncompliance in treatment is a significant problem.25 this noncompliance issue could account for the existence of a significant number of previous follow - up attempts .
nevertheless , multiple other factors could contribute to this result , namely the presence of common personality traits in dsh adolescents , which can lead to difficulties in establishing a therapeutic relationship . in the clinical practice ,
when an adolescent is observed in a psychiatric consultation , suicidal ideation should be assessed by the first visit .
nevertheless , 31% of the dsh subjects in our sample denied the presence of suicidal thoughts at the time of the first interview . in these cases ,
suicide risk assessment needs to be carefully performed as previous dsh9,26 is a major risk factor for completed suicide , meaning that even if suicidal ideation is denied , the risk is maintained
. concerning the reported psychosocial difficulties , we found no significant differences in their categories between the two groups , with family and affective conflicts being the most reported categories of psychosocial difficulties in both groups .
nonetheless , we documented that the group with dsh had in average more psychosocial difficulties than the control group .
this finding agrees with previous studies reporting that self - harm often follows a period of stress or psychosocial difficulties.13,14,27 furthermore , we documented a difference concerning the therapeutic goals of the present follow - up between the two main groups , as the wish to change family relations and school situation was less frequently reported in the dsh group .
the case group also reported less average therapeutic goals , although it referred more psychosocial difficulties than the control group .
this fact could be accounted by previous ineffective follow up attempts or by negative expectations regarding treatment ( eg , belief that nothing could help ; seeking help is a
sign of weakness ; reluctance to admit having mental health problems and being too embarrassed to seek help ) , which , according to previous studies , are common thoughts in youth who later commit suicide.28 this can also be related to nonproductive coping strategies ( like avoidance behaviors or less focus on the problem).15 the low expectations concerning change in family relations or in the school situation by the dsh group is a fact of concern , since other studies about adolescent self - harm prevention point to family , friends , and school as the main sources of support in preventing suicidal behavior ( which are believed to be more pertinent than external helping agencies in this matter).29 interestingly , the most frequently referred feature that subjects in dsh group wished to change were personality traits . we think this probably reflects that the adolescents in our sample had at least a minimum degree of insight to help them identify some traits , like impulsivity or harm avoidance , commonly associated with suicidal behavior.21
lastly , we share the opinion that there are a number of limitations that should be noted when interpreting these results .
one of them is that there could be a bias in our sample , since its subjects were recruited from two different types of consultation : an adolescent consultation ( general ) and a youth suicide consultation ( very specific to the issue of suicidology ) .
moreover , this sample is representative of the adolescent population of our adolescent psychiatric consultations ; in fact , self - harm involves many local and cultural issues , which limits generalization .
as to the size of our sample , we acknowledge that numbers are important in every study and that although we obtained almost 100 adolescents , the study would be stronger with larger numbers .
importantly , this study is retrospective , using clinical case files and completing interviews , so it would be fair to assume that errors in data recording and the lack of monitoring of the data in a prospective fashion can be a bias .
also , as no assessment scales were used , more specific diagnosis categories were not obtained , and a quantitative analysis of suicide risk , depression , or impulsivity was not performed .
we hereby recognize this limitation , but wish to underline that one of our goals was precisely to determine simple clinical features that characterize our adolescents with dsh .
this certainly agrees with the theory that in clinical practice , and for many different reasons , assessment scales are not always used . on the other hand , performing a clinical interview is mandatory when evaluating an adolescent in a psychiatric consultation , rendering it possible to collect most of the information we presented in this study and that we consider easily accessible .
the profile of the adolescent with dsh , in our consultation , is as follows : an adolescent who is referred from the emergency department in which the referral motive is mainly dsh or ideation , is usually depressed , with previous follow - up attempts , and discloses suicidal ideation when questioned .
this adolescent has several psychosocial difficulties , mainly family conflicts and affective conflicts , and has negative expectations regarding treatment .
we aimed to obtain more knowledge about our local sample by describing the adolescents who harm themselves that we see in our practice .
we traced a profile that is over - simplistic , but reveals some important issues for mental health professionals who work with adolescents .
the study was limited because no assessment scales were used ; further studies could use specific instruments to evaluate how adolescents who dsh cope differently with psychosocial problems and how psychopathological measures differ .
also more in - depth interviews can also be conducted to collect supplementary qualitative data , like reasons for the adolescents low expectations concerning change of family relations or school situation by the dsh group .
there is a need to recognize and prevent self - harm in adolescents before they reach emergency departments
. it would be interesting to study if dsh could be reduced if primary care physicians or school teachers recognized this problem at an early phase .
an important conclusion is that working with adolescents with dsh is difficult and can not be done solely on a biological approach .
psychosocial difficulties , family dysfunction and negative expectations have to be addressed and included in the therapeutic plan . preventing and treating dsh ( and frequently associated depression ) in adolescents is important and could be a lifesaving measure .
adolescent suicide is a growing concern and a major cause of death in the youth .
there is no local data about the clinical characteristics of adolescents followed in psychiatric consultations that deliberately harm themselves .
this case control study describes the clinical profile of adolescents with dsh in our consultations . | ### Summary:
: deliberate self - harm ( dsh ) among adolescents is a high - risk condition for suicide .
the aim of the present study is to describe the characteristic clinical features of adolescents with dsh according to our local context ( lisbon , portugal ) , using easily available information from clinical settings .
a case control study was constructed from a sample of 100 adolescents ( aged 12 to 21 years ) .
the sample was divided into two groups : adolescents with and without dsh .
case files were examined and data was completed by clinical interviews .
demographic , psychosocial , and psychopathological data were assessed and compared .
ninety - eight subjects completed the protocol .
the dsh group was associated with the following : suicidal ideation or suicidal behavior as consultation motive , emergency room referral , previous follow - up attempts , suicidal ideation , psychosocial difficulties , or lack of therapeutic goals .
there was a nonsignificant trend towards diagnosis of depression in the dsh group .
these results reflect our clinical practice with adolescents and add data about teenagers who self - harm to the literature .
prevention and early recognition of dsh ( and frequently associated depression ) in adolescents are essential and could be life - saving measures . an integrated approach , which takes into account psychosocial difficulties , family dysfunction , and negative expectations , seems to be of great importance . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: surgical resection provides the best opportunity for a positive outcome for patients with gastrointestinal stromal tumours ( gists ) , with a minimally invasive approach improving postoperative recovery .
tumour location within the stomach , particularly proximity to the oesophagogastric junction ( ogj ) , is often cited as a reason for a particular surgical technique , including
tumours located close to the ogj are particularly difficult to excise because of the high risk of causing strictures or leakage at the site of resection . a laparoscopic and endoscopic combination surgery ( lecs ) for tumours of the cardia or those in close proximity to the ogj has been described in several small studies [ 2 , 4 ] .
we describe utilizing this novel technique in the treatment of a patient with a gist located high in the cardia , close to the ogj .
a 68-year - old female underwent a computed tomography ( ct ) scan of her thorax and abdomen due to the presence of a ret oncogene variant and a history of recurrent tubulovillous polyps of the large bowel .
polyp in the lumen of the stomach ( fig . 1 ) and large hiatus hernia with dilation of the lower oesophagus .
subsequent endoscopic ultrasound showed a lesion suspicious for a gist located within 2 cm of the ogj .
figure 1:sagittal and axial ct images showing a large polyp on the posterior gastric wall .
the decision was made to surgically remove the tumour and perform concurrent hiatus hernia repair .
the tumour 's proximity to the ogj and current evidence suggested that lecs would provide an improved outcome compared with a more radical resection .
the patient was placed under general anaesthetic , optical access was acquired via the left upper quadrant of the abdomen using a 12-mm xcel ( ethicon ) trocar and co2 pneumoperitoneum was created .
two 5-mm xcel ( ethicon ) trocars , one 12-mm xcel ( ethicon ) trocar and a nathanson liver retractor ( fig .
figure 2:(a ) instrument access points and ( b ) gastrotomy positions on the anterior stomach wall and gist location close to the ogj .
( a ) instrument access points and ( b ) gastrotomy positions on the anterior stomach wall and gist location close to the ogj . a balloon trocar ( covidien ) was inserted and inflated through a small incision in the anterior stomach , allowing the stomach to be elevated to the anterior abdominal wall .
endoscopic assistance allowed intermittent insufflation of the stomach to maintain an adequate surgical field and also aided in location of the ogj .
the tumour was directly visualized a 3.5 cm 2 cm sub - mucosal , pedunculated mass on the posterior wall , close to the ogj .
the tumour was lifted away from the posterior wall with the grasper and a stapled excision performed using an endogia ( covidien ) ( fig .
the tumour was placed into an endobag and removed endoscopically , and the gastrotomies were closed with 2 - 0 vicryl . a crural repair and a partial fundoplication
were completed with 2 - 0 ethibond.
figure 3:(a ) tumour elevation and stapler placement .
histology showed low - grade gist , categorized via national institutes of health ( nih ) risk table .
the tumour was < 5 cm , and there were < 6 mitoses per 50 high - powered fields .
follow - up ct scan 5 years post - op showed no recurrence of tumour .
the primary aims of the surgery are to remove the gist with negative resection margins and to preserve anatomical function .
tumour characteristics including size , type of growth ( i.e. endophytic or exophytic ) and distance from the ogj are often cited as indications for a particular surgical technique .
ohashi described a new technique for treatment of gastric cancers in which laparoscopic instruments were passed into the stomach and all resection completed intraluminally .
posterior wall tumours showing predominantly endophytic growth can be resected using a laparoscopic , transgastric technique through gastrotomy in the anterior wall .
this is advantageous because it permits direct visualization of the lesion and better control of the surgical margin .
however , gastrotomy is associated with intraperitoneal spillage of gastric contents and bleeding from the gastric wall .
intraoperative tumour rupture during a transgastric procedure also carries the risk of peritoneal seeding . a combined laparoscopic
endoscopic approach has been utilized in a number of patients with tumours close to the ogj [ 1 , 2 , 9 ] , but there is a paucity of literature in this area ( particularly in the uk ) on details such as success rates , complications and follow - up .
taniguchi et al . reported a case study of a patient undergoing successful lecs of a tumour located in the cardia .
more recently , shim et al . reported a series of six patients with tumours close to the ogj .
they concluded that this hybrid technique was safe , technically feasible and useful for resecting tumours close to the ogj .
a number of other case reports and small studies support these conclusions [ 2 , 4 ] .
current literature suggests a number of advantages to this technique . decreased deformity or stenosis of the ogj , precise tumour location , determination of stomach port sites , confirming haemostasis at the staple line , retrieval of tumour and checking for air leakage post - resection
furthermore , endo - linear stapler usage minimizes potential blood loss during tumour resection , decreases operation time and requires no suturing of resected stomach wall . in this case , decreased peritoneal seeding of the tumour and decreased fracturing during resection , together with visualized port placement and accurate location of the ogj , were the primary reasons behind selecting lecs .
this case study demonstrates that lecs is a safe and effective method of treating tumours close to the ogj .
the restriction of anatomical damage and more conservative surgical nature of the lecs are of particular importance for both short- and long - term patient recoveries .
the flexibility of instrument placement also allows removal of the gist with concurrent repair of a small hiatus hernia .
the 7-month and 4-year follow - ups have highlighted no short- or long - term sequelae , adding to the growing body of literature supporting this surgical approach .
however , due to the recent developments in this area , larger studies are needed to confirm technical efficacy and longer - term patient outcomes .
| ### Summary:
: tumours close to the oesophagogastric junction ( ogj ) are difficult to excise due to high risk of complications .
laparoscopic and endoscopic combined surgery allows minimally invasive access while increasing tumour visualization .
computed tomography ( ct ) scanning of a 68-year - old female demonstrated a lesion suspicious of a gastrointestinal stromal tumour located 2 cm from the ogj on the posterior gastric wall .
stapled excision was performed intragastrically and followed by endoscopic removal .
gastroscopy 7 months post - op and follow - up ct scan at 5 years demonstrated no recurrence of the primary tumour and no new disease .
laparoscopic and endoscopic combined approach is a safe and effective method of removing tumours close to the ogj . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: falls during daily activities are a concern in stroke patients who have central nervous
system damage . falling stems from the inability to lift the ankle ( dorsiflexion ) triggered
by the failure of central nervous system mechanisms caused by stroke .
previously , duncan1 reported that a
stimulus input in the plantar calcaneal region in an individual with central nervous system
damage induced a dorsiflexion reflex as a neurophysiological action .
this mechanism is known
as heel - gait - cast - treatment2 .
later
research included studies such as one by charles et al.3 on electromyographic analysis of the effects of a calcaneal region
stimulus in individuals with post - stroke hemiplegia on activation of dorsiflexion muscle
activity .
it has also been reported that in stroke patients , posture and gait4 , 5 were affected by
stimulating6 , 7 the peroneal nerves within an ankle foot orthosis ( afo ) .
additionally , there have been some reports in which dynamic motion data were changed by
neurological intervention in this manner . however , there are few studies on the effect of
afo on gait with a focus on energy , which is an indication of the total efficiency .
haruna
and his co - workers8 reported that the
continuous use of a gait solution afo developed by yamamoto9 , 10 increased the rate of
mutual exchange between kinetic energy and potential energy in the gait of a hemiplegic
patient .
this change showed that use of the gait solution afo improved the energy conversion
efficiency of the body s center of gravity using the so - called inverted pendulum .
we
investigated the effects of 27 different shapes and sizes of heel pads on gait using a
plantar flexion resistive afo in healthy subjects11 .
this study showed that heel pads fixed to an afo retained the
center of pressure ( cop ) at the heel and increased the lever arm of the ground reaction
force vector to the ankle related to the dorsiflexion moment .
however , there is a relative lack of research
describing the effect of a heel pad on gait in hemiplegic patients .
further studies are
therefore required to elucidate the effect of a heel pad on hemiplegic gait .
the simplest method of calculating energy by using positional information on cog is to use
the energy conversion efficiency calculation reported by cavana et al12 .
cavana13 integrated the force component ( acceleration component ) obtained
from a force plate to calculate the kinetic energy and potential energy , and they calculated
the energy conversion efficiency from a physics standpoint .
this enabled us to focus on the
conversion of potential energy and kinetic energy obtained from the movement of the cog .
this study aimed to analyze the effect of heel pads in ankle - foot orthoses on dynamic motion
aspects of gait in stroke patients from the viewpoint of energy conversion efficiency .
fourteen chronic stroke patients ( 9 males and 5 females ; age , 5910 years ) who were
ambulatory and had lower extremity motor function categorized as brunnstrom20 stage iv participated in the study .
their
characteristics are shown in table 1table 1.subject characteristicsevaluation parametersa1a2a3a4a5a6a7a8a9a10a11a12a13a14age ( y)6544367059495263646668695758gender ( m : male , f : female)mffmmfmmmmmfmfparetic sideleftleftrightleftrightleftleftrightrightrightrightrightleftrightbrunnstrom stage ( lower limb)ivivivivivivivivivivivivivivrom ( paretic ankle):plantarflexion dorsiflexsion405405452045204020400451545204074010401535204504010foot clonus++++++type of everyday use orthosisplsplsplsplsjafoplsjafoplsplsplsplsplsjafoplsaverage walking speed ( m / min)50.433.642.0 48.0 45.344.441.852.342.745.649.539.540.538.8pls : plastic leaf spring afo , jafo : joint afo . selection criteria included subjects who could follow verbal instruction , did
not have any orthopedic disease , used an afo routinely on a daily basis , and were able to
walk independently .
the selected subjects in this study were able to walk forward by means
of a heel strike when using an afo .
there was no restriction regarding cane use , or lack
thereof , in the interest of ensuring an adequate number of subjects .
pls : plastic leaf spring afo , jafo : joint afo this study was conducted after obtaining approval from the ethics committee of hokkaido
university of science .
the content of the study was explained to cooperating research
facilities and the participants in order to obtain their consent , and written informed
consent has been obtained from each subject .
the afo9 , 10 used for the study was a joint afo ( jafo , gait - solution - design ,
pacific supply , japan ) , as shown in fig .
1.joint afo used in this study , and measurements were begun after the angle and resistance of the orthose the
afo9 , 10 used for the study was a joint afo ( jafo , gait - solution - design ) , as
shown in fig . 1 , and measurements were begun after
the angle and resistance of the orthoses were adjusted to match each subject s condition
over a three - month trial period .
joint afo used in this study the study design was an a - b - a single - system design ( fig .
. 2.study protocol ) . as a baseline , only jafos tailored for each subject were used for one trial month
( a1 to a2 ) .
next , the jafos were fitted with 3-mm - thick rubber heel pads with 60 degrees of
hardness at the plantar calcaneal region of the jafos , as shown in fig . 3fig .
3.heel pad , in order to examine the effect of the press - in force on the calcaneal region ; these
heel pads were used for one month ( b1 to b2 ) .
finally , the heel pads were removed , and only
the jafos were used for one month ( a3 to a4 ) .
measurements were taken at a1 to a4 , and were implemented on the same days for a2 and b1
and for b2 and a3 , falling under the timings for the heel pad intervention .
this was to
examine the following : stability of the baseline by comparing a1 to a2 ; immediate effects of
the heel pads by comparing a2 to b1 ; impact of the long - term effects of the heel pad
intervention by comparing a2 to b2 ; and the carry - over effects by comparing b2 to a4 .
gait was measured using a three - dimensional ( 3d ) motion analysis system vicon - mx ( with six
cameras , manufactured by vicon , oxford , uk ) and five force plates ( amti ) .
the sampling frequency for each
measuring instrument was 240 hz for infrared cameras and 960 hz for floor reaction
force - based measurements .
the measurement path surface was 9.5 m , with three force plates
arranged in the middle on the left side and two on the right side . for 3d motion
measurement , reflective markers with a 14-mm diameter were applied to 21 points on the body .
the application positions were the forehead , the right shoulder blade , both acromions , the
lateral epicondyles of both humeri , both radial styloid processes , both anterior superior
iliac spines , both posterior superior iliac spines , both hip joints ( the distal 1/3 point
connecting the anterior superior iliac spine and great trochanter ) , both knee joints ( the
anteroposterior radius 1/2 point , 1/3 point , and midpoint ) , both ankle joints ( the lateral
malleolus center for the healthy side and the orthosis axis center for the orthosis side ) ,
both calcaneal regions and both fifth metatarsal heads .
the point of interest during
measurement on the walking path was data acquisition for 10 trials where one foot was placed
on a force plate .
the data obtained from the 3d motion analysis system were used to create middle markers
between markers with the vicon s body builder ( example : midpoints between the knee joint and
ankle joint markers ) .
thereafter , the walking speed , stance - phase maximum height of the cog , dorsiflexion moment
( maximum value of the loading response ) , and floor reaction force action point ( cop ) were
found from the plug - in - gait model .
the cop retention rate : the cop of the traveling direction component during heel rocker was
extracted , and a secondary function was calculated as per the dotted line in fig .
this quadratic function represents the progression of cop . for instance , a greater
quadratic function shows that the plantar cop is advancing quickly forward , which is an
index for examining the effects of the heel pad .
calculation of the second - order coefficient of cop the energy conversion efficiency : using the research methods of cavagna et al.12,13,14,15,16,17,18,19
makes it possible to calculate the energy conversion efficiency from the cog obtained from
the 3d motion data .
this is done by applying a reverse pendulum theory using the force of
gravity to calculate the energy conversion efficiency during walking from the kinetic and
potential energies during walking .
gait was divided into the paretic stance and the non - paretic stance using cog displacement
in the vertical direction , as per fig . 5fig .
then , the reverse pendulum motion was separated into a rising section and a falling
section from the information on the lowest point and the highest point for the respective
cog heights , and the energy conversion efficiency was calculated in each section as follows .
to calculate the kinetic energy and potential energy during ambulation ,
the kinetic energy
( ek.y ) in the direction of progress of the body cog was calculated by the formula ,
ek.y=1/2mvy , the kinetic energy ( ek.z ) in the vertical direction by
ek.z=1/2mvz , the potential energy ( ep ) by ep = mgz , the total kinetic energy(ek )
by ek = ek.y+ek.z , and the total energy ( etot ) by etot = ek+ep , where m is the body mass , g is
the acceleration due to gravity ( 9.8 m / s ) , vz is the vertical velocity of cog ,
and vy is the velocity in the direction of cog progress .
separate phases of mechanical energy of cog the external work for accelerating the cog in the direction of progress was calculated
using formula 1 , the external work of raising the cog in the vertical direction against
gravity by formula 2 , and the external work generated by the muscles to move the cog was
calculated using formula 3.wy=ek.y
( 1),wz= ( ek.z+ep )
( 2),wext=etot ( 3 ) , where is the amount of energy increase or decrease , and is the summation of the data of
. conversion efficiency ( % recovery ) was calculated using formula
4.%recovery=(|wy|+|wz|-wext ) ( |wy|+|wz| ) 100 ( 4 ) analysis methods : for each assessment parameter , data after heel pad intervention were
standardized using the mean and standard deviation of the baseline ( a1 ) .
this made it
possible to nullify the effects between subjects and the differences in units between
assessment parameters to look at the relative growth rate versus the baseline . in the
statistical analysis
, data were analyzed using the statistical software , excel - toukei 2008
( social survey research information co. , ltd . ) .
friedman test and steel - dwass - test for
multiple comparisons were performed to compare the standardized numerical values .
evaluation parameters standardized by baseline a1 are shown in table 2table 2.evaluation parameters showing the changes from baselinenormalized parametersincrease rate ( % ) no pada2padb1padb2no pada4retention rate of cop0.32.2 10.68.5** 23.515** 12.112**ankle dorsiflexion moment 1.01.213.41652.915**27.337paretic - side cog 0.11.06.82.0 * 9.12.8**8.53.4**non - paretic - side cog 0.21.24.33.27.42.8**7.12.3**paretic - side upward energy conversion
efficiency2.02.0 12.01526.012**20.013**paretic - side downward energy conversion
efficiency1.22.03.46.7 1.98.08.23.9non - paretic - side upward energy conversion
efficiency4.12.98.81221.49.8**22.212**non - paretic - side downward energy conversion
efficiency1.44.219.48.8**16.88.8**21.98.8**values are group mean deviation .
comparisons of a1 to a2 : no heel pad group as a control , b1 : immediate
intervention effects of the heel pad , b2 : long intervention effects of the heel pad , and a4 :
carry - over effects after removing the heel pad are also shown in table 2 .
significant difference base line
a1 . : p<0.01 , : p<0.05 the parameter of retention rate of the cop indicated retention of the cop at the heel as
immediate effects ( table 2-b1 ) .
in contrast ,
there were no immediate effects in the paretic - side cog ( table 2-b1 )
. however , long - term effects were observed in the
paretic - side cog ( table 2-b2 ) .
in addition , a
significant correlation was shown between retention rates of the cop and paretic - side cog
( table 3table 3.matrix of correlation between parametersretention rate ofcopankle dorsiflexionmoment paretic - sidecognon - paretic - sidecogretention rate of cop-0.620.560.39ankle dorsiflexion moment * * -0.640.44paretic - side cog * * * * -0.72non - paretic - side cog * * * * * * -upper part shows correlation coefficients .
p<0.01 paretic - side upward energy conversion efficiencies at b2 were also significantly increased
with long - term effects in the paretic - side cog ( table
2-b2 ) .
all parameters of long - term effects ( table 2-b2 ) and carry - over effects ( table
2-a4 ) in energy conversion efficiency were significantly increased except the
paretic - side downward .
the heel pads fixed the cop at the heel rocker section during walking , and they increased
the ankle joint dorsiflexion moment . in this regard , it appears the heel pads fixed the cop at the heel rocker section during
walking , and they increased the ankle joint dorsiflexion moment . in this regard , it appears
that the phenomenon of cop retention ( fig .
6.mechanism of cog rise ) maintained the distance between the floor reaction force acting line and the ankle
joint center ( fig .
the increase in the ankle
joint dorsiflexion moment also caused the paretic - side cog height to rise .
this is likely
because there is a large ankle joint dorsiflexion moment in the paretic - side heel rocker
period , and this produces forward rotation of the paretic lower extremity around the heel
( fig .
6 - 4 ) , indirectly causing the paretic - side
cog height to rise ( fig . 6 - 5 , 6 )
. mechanism of cog rise in general , the cog height in normal walking peaks at mid - stance , and it has left - right
symmetry . during post - stroke walking , however , often a decrease in the support of the
paretic side or other factors causes the paretic - side cog height to have a lower maximum
value than the non - paretic side20,21,22 ,
resulting in a loss of symmetry ( fig .
the heel
pads , however , caused the maximum value of the paretic - side cog height to rise , which
reduced the left
we do , however , feel that despite the lack of an increase in the dorsiflexion moment , the
appearance of raising the paretic - side cog as an immediate effect ( table 2-b1 ) was caused by the higher energy conversion efficiency
in the non - paretic - side descent in the direction of travel ( table 2-a4 ) .
this indicates that when the energy conversion
efficiency on the non - paretic side increases , the paretic foot can land in a state where
kinetic energy is maintained , as in fig .
6 - 1 , and
an effect of retaining cop is also obtained , thus yielding a dual effect on increasing the
cog height in the paretic stance
it therefore appears that even a slight moment in the dorsiflexion direction
contributes to raising the cog .
we also obtained the long term effect on all parameters except for the paretic - side
downward energy conversion efficiency .
these results coincided with the results of previous
studies21,22,23 , which showed that the
continuous use of an afo increased the kinetic energy of non - paretic side descent .
the present study was an experimental investigation of the effect of heel pad intervention
on dynamic motion assessment parameters using a single - system a - b - a design in 14 stroke
patients .
the results showed that a heel pad attached to the calcaneal region of an afo caused slight
retention of the cop at the heel during the heel rocker function along with cog elevation
and raised energy conversion efficiency , especially on the non - paretic side . | ### Summary:
: [ purpose ] this study aimed to analyze the effect of heel pads in ankle - foot orthoses on
dynamic motion aspects of gait in stroke patients from the viewpoint of energy conversion
efficiency .
[ subjects ] fourteen chronic stroke patients who were ambulatory and had lower
extremity motor function categorized as brunnstrom stage iv participated in the study .
[ methods ]
a three - dimensional motion analysis system was used to assess the effect of heel
pad intervention on dynamic motion gait parameters using a single - system a - b - a design .
[ results ] the results showed that a heel pad attached to the ankle - foot orthosis caused
significant retention of the center - of - pressure at the heel during the heel rocker
function and significant increase in the dorsiflexion moment and the height of the center
of gravity .
[ conclusion ] the present study showed that a heel pad attached to the
calcaneal region of an ankle - foot orthosis caused slight retention of the
center - of - pressure at the heel during the heel rocker function along with center of
gravity elevation in the stance phase and improved the energy conversion efficiency ,
especially on the non - paretic side . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: physeal separations in newborns represents a problem from both the diagnostic and treatment point of view . in developed countries , neonatal septic osteomyelitis and septic arthritis are uncommon and represent a problem with respect to the differential diagnosis among several other disease ,
that often are not strictly restricted in the orthopaedic and traumatology area and frequently needing all diagnostic resources to obtain the correct diagnosis in order to get the best knowledge of the actual condition and to avoid an unsuitable treatment or an unexpected anatomical situation in case of surgical exposition .
therapy needs to be initiated as soon as possible in order to prevent the potentially adverse anatomic and functional consequences [ 1 , 2 ] .
association between a septic event and physeal separation is extremely rare . in order to illustrate the difficulties associated with a proper diagnosis and management
a 28-day - old caucasian newborn was brought to the paediatric emergency department for symptoms involving 2 days of elevated temperature .
the infant was born by normal spontaneous vaginal delivery ( nsvd ) , her mother received normal prenatal care with no evidence of any particular problems , and the pregnancy was uncomplicated . at the time of admission , symptoms included fever , chills and irritability . with the symptomatology suggestive of an abdominal problem , she was evaluated by the paediatric surgeon who reduced an inguinal hernia and admitted the infant to the paediatric surgery department for observation .
the following day the patient s clinical conditions did not improve , high fever and irritability persisted . a complete blood count ( cbc ) with differential showed leukocytosis with a neutrophylic predominance .
clinical conditions were still suggestive of an abdominal problem . an anteroposterior direct abdominal x - ray evidenced bowel loop distension ( fig . 1 ) .
three days after admission the clinical condition remained unchanged : a diagnosis of intestinal occlusion was made and an explorative laparoscopy was performed but no evidence of an intestinal problem was present . during the same surgical session
a bilateral open inguinal hernia repair was performed with bilateral reconstruction of the inguinal canal.fig .
1radiograph 3 days after admission : distension of the bowel loops is evident ; note the flexion and rotation of the inferior left leg radiograph 3 days after admission : distension of the bowel loops is evident ; note the flexion and rotation of the inferior left leg two days postoperatively conditions were unchanged while a swelling of left hip and thigh region became noticeable .
the skin was red and warm to the touch and the left leg was flexed and rotated . at this time a hypothesis of liquid collection in the hip - thigh region was formulated by the paediatric surgeon and needle drainage under ultrasonography was performed with evidence of pus presence which was immediately sent to the microbiological department for culturing . only at this time was broad - spectrum antibiotic parenteral therapy started ( ceftazidime 200 2 mg , amikacina 40 2 mg , metronidazole 60 2 mg ) .
immediately after needle drainage and with the start of antibiotic therapy , status improved but without complete recovery .
the persistence of a septic condition and the warm and reddened skin in the left hip region were suggestive of septic arthritis of the hip .
new x - ray and a new ultrasonography studies were performed with a correct position of the pelvis .
the x - ray study with the correct position of the pelvis demonstrated the dislocation of the femoral head ( fig .
2 ) , while the ultrasonography findings revealed the presence of parostal proximal femoral shaft liquid collection and an undefined morphology of the hip .
no more imaging was thought to be required and a diagnosis of septic hip arthritis with consequent hip dislocation was formulated ( fig .
, the first results from the microbiology culture became available , with evidence of growth of gram - positive cocci ( staphylococcus aureus became evident 2 days later ) .
parenteral antibiotic therapy was modified with the suspension of ceftazidime and metronidazole ; only amikacin was continued and cefotaxime was added.fig .
2second radiograph : while performing that new radiograph , the proper pelvis position was held by an orthopaedic surgeon and it is possible to note a dislocation of the femoral headfig .
3after orthopaedic evaluation and new imaging in correct position a diagnosis of septic arthritis with consequent hip dislocation was formulated ( as represented ) and surgical open drainage was indicated .
imaging was thought to be sufficient second radiograph : while performing that new radiograph , the proper pelvis position was held by an orthopaedic surgeon and it is possible to note a dislocation of the femoral head after orthopaedic evaluation and new imaging in correct position a diagnosis of septic arthritis with consequent hip dislocation was formulated ( as represented ) and surgical open drainage was indicated .
imaging was thought to be sufficient ten days after admission the infant underwent open surgical drainage by an orthopaedic team of the presumed hip joint septic arthritis by an anterior approach ( smith petersen approach ) .
actually , only at time of surgery was it possible to observe a physeal separation between the epiphysio - trochanteric nuclei complex and the femoral shaft , with purulent liquid collection , but the hip joint plugged by the femoral head and the epiphysio - trochanteric growing nucleus was not involved in the septic process ( fig .
the hip joint was opened by an anterior approach and the absence of pus presence inside the joint was confirmed . only at this time
was it possible to make the proper diagnosis of septic physeal separation between the epiphysio - trochanteric nuclei complex and the shaft of the proximal femur with clear hip joint ( fig .
4intraoperative finding : physeal separation between the epiphysio - trochanteric nuclei complex and the femoral shaft .
( a ) hip joint was plugged by the femoral head and ( b ) the growing nucleus was not involved in the septic process ( c)fig .
we were not in presence of a septic hip arthritis with consequent hip dislocation as thought ( a ) , but the correct diagnosis was septic physeal separation between the epiphysio - trochanteric nuclei complex and the femoral shaft ( b ) intraoperative finding : physeal separation between the epiphysio - trochanteric nuclei complex and the femoral shaft .
( a ) hip joint was plugged by the femoral head and ( b ) the growing nucleus was not involved in the septic process ( c ) only at the time of surgery was it possible to achieve the correct diagnosis .
we were not in presence of a septic hip arthritis with consequent hip dislocation as thought ( a ) , but the correct diagnosis was septic physeal separation between the epiphysio - trochanteric nuclei complex and the femoral shaft ( b ) the epiphysio - trochanteric complex was gently reduced back to the anatomic position and stabilized with kirschner wires .
one suction drain was positioned inside the joint and another next to the proximal femur .
6surgical procedure : the epiphysio - trochanteric nuclei complex was gently reduced back to the anatomic position and stabilization with kirschner wires was obtained ( a , b , c , d ) . after surgery , immobilization with plaster spica was provided ( e ) surgical procedure : the epiphysio - trochanteric nuclei complex was gently reduced back to the anatomic position and stabilization with kirschner wires was obtained ( a , b , c , d ) .
after surgery , immobilization with plaster spica was provided ( e ) immediately after surgery the clinical conditions of the patient improved , with complete normalization of body temperature and absence of irritability .
parenteral antibiotic therapy was again modified ( netilmicin 8 3 mg , and oxacillin 200 2 mg ) .
postoperative x - ray evaluation showed good alignment between the femoral shaft and the epiphysio - trochanteric nucleus , with a perfect position of the femoral head inside the acetabulum .
the infant was discharged 2 weeks following the last surgical procedure and continued with antibiotic therapy ( riphampicine 25 mg 1 tab bis in die for 3 weeks ) .
the patient followed - up at 2.5 , 6 , and 16.5 months , with progressive recovery of range of motion and good radiologic findings . at 4 years of age
, her last follow - up showed that the hip joints were completely symmetric on x - ray imaging and equal in range of motion ; there was no limb - length discrepancy or deformity ,
the child did not report any pain and was perfectly able to perform her daily activities including unlimited walking , running , and squatting ( fig . 7).fig . 7follow - up radiographs at 2.5 months ( a ) , 6 months ( b ) , and 16.5 months ( c ) and 4 years ( d ) .
when last reviewed at 4 years , range of motion was complete and symmetric , there was no limb - length discrepancy or deformity , the child did not complain pain and was perfectly able to perform her daily activity including unlimited walking , running , and squatting follow - up radiographs at 2.5 months ( a ) , 6 months ( b ) , and 16.5 months ( c ) and 4 years ( d ) .
when last reviewed at 4 years , range of motion was complete and symmetric , there was no limb - length discrepancy or deformity , the child did not complain pain and was perfectly able to perform her daily activity including unlimited walking , running , and squatting
physeal separations in neonates occur rarely [ 37 ] and femoral involvement in physeal separation may occur either proximally or distally .
concomitant physeal fracture and infection are very uncommon , and a complete separation of an epiphysis is described as a rare complication of neonatal osteomyelitis or septic arthritis . the literature appears to indicate the hip joint as the most common site of epiphyseal slip as well as the most common site involved in a neonatal septic process . because of some anatomic and histological characteristics ( large sinusoidal channel , loose metaphyseal cancellous structure , thin cortex , and loosely attached periosteum ) typical of the neonatal age , the juxtaepiphyseal intraosseus pus can easily reach the subperiosteal space and affect the local soft tissue and joint .
the confinement of bone destruction to the juxtaepiphyseal area with early cortical perforation and stripping of the periostium appears to have the capacity to induce a mechanism which leads to the loosening of the epiphysis .
this is the process that leads to these two possible complications ( septic arthritis and physeal separation ) unique to the neonatal age [ 810 ] . today
, in developed countries , septic arthritis and acute osteomyelitis are quite uncommon in the very first days of life .
chorioamnionitis , prolonged membranes rupture , maternal chills or fever are considered risk factors for the child s septic events .
macrosomia , breech presentation , difficult or precipitous vaginal delivery , and a caesarean section could predispose to birth trauma .
scurvy should always be considered in the event of a neonatal fracture when the history is negative for trauma .
nonaccidental injury should be considered , particularly when other signs of violence are present . in our case maternal risk factors for neonatal septic events were absent and delivery was uneventful and nontraumatic .
recognition of a physeal separation in a newborn is difficult , whether secondary to trauma or following a septic event .
physical findings of septic arthritis or osteomyelitis could be present , but multiple clinical evaluations could still be nonconclusive due to the patient s early age and to the difficulty involved in reaching a timely and accurate diagnosis . in our case the newborn was admitted with a nonspecific symptomatology involving fever , chills , and irritability . no local sign suggestive of a hip infection
was present . when first evaluated by the paediatric surgeon she was thought to have an abdominal problem .
a hypothesis of fluid effusion was formulated only after considering the failure of the prescribed medical therapy , the negative findings obtained from an explorative laparoscopy , and the appearance of localized cutaneous redness and swelling .
this diagnosis was later confirmed by a needle percutaneous drainage which evidenced the presence of purulent material . only at this time
was parenteral broad - spectrum antibiotic therapy started and , 8 days after admission , was an orthopaedic surgeon consulted and the diagnostic hypothesis of a septic arthritis formulated . in newborns , standard radiographs
may not identify the epiphysis because of the lack of ossification of the growing nucleus , and even if the ossification center is present , its minute dimension could be equivocal in plain radiographs which would not be able to detect a displacement .
only if the fracture involves part of the metaphysis may a tiny bone fragment separation appear .
a good view of the hips requires correct positioning of the pelvic ring , which can only be achieved when the lower extremities are firmly held in the appropriate position .
our patient underwent an initial radiology study ( x - ray ) that in reality was aimed at evaluating the abdomen but , due to the small size of the child , was able to show a significant section of the two lower extremities .
when the clinical condition changed and the hypothesis of a septic arthritis became evident , a second x - ray was performed .
this time the child s legs were strongly held by the orthopaedic surgeon in the correct position and it was possible to notice the hip displacement . at this time , a review of and comparison with the initial films allowed us to formulate some doubt regarding the affected hip but the findings remained inconclusive due to the incorrect positioning of the lower extremities which disallowed an accurate clinical evaluation .
this is an excellent example of the need to properly position the patient during the radiologic process .
ultrasonography is valid exam for the hip in newborn , able to show liquid presence inside the hip joint suggestive of septic arthritis . in our case ultrasonography (
performed only when the local condition suggested a hip involvement ) , was able to demonstrate the presence of a liquid collection from the iliac wing to the inguinal canal , as well as confirm that the liquid collection was strongly contiguous with the hip joint where the articular synovial space was significantly increased ; these findings were suggestive of septic arthritis with an extra - articular liquid collection .
a second ultrasonography was directly performed by the orthopaedic surgeon after the second x - ray was obtained , and particular attention was given to maintaining the correct position during the us scanning .
ultrasound findings showed periarticular and proximal parostal femoral shaft liquid collection while the morphology of the hip was undefined . on the base of the clinical condition and of the radiological findings ,
a hypothesis of septic hip arthritis with consequent hip dislocation was formulated and an open surgical drainage was performed .
the lack of additional preoperative imaging limited the diagnostic hypothesis and led to a wrong preoperative planning . only at the time of surgery was the correct diagnosis of physeal separation between the epiphysio - trochanteric nuclei complex and the femoral shaft formulated .
the lesson learned is to assure that , when possible , complete and detailed preoperative imaging should be obtained in order to have a correct preoperative diagnosis fundamental in planning the appropriate surgical procedure .
literature reports computed tomography ( ct ) and magnetic resonance imaging ( mri ) as useful imaging devices able to yield more detailed knowledge of the actual condition [ 3 , 12 , 13 ] .
it is our opinion that a mri study would have been preferable over a ct evaluation as it would have spared the young patient exposure to ionizing radiation and would have also furnished greater details of the area s soft tissues .
mri might have detected the correct cause of the problem , thus avoiding an incorrect diagnostic hypothesis that led to the abdominal surgical procedure .
partial or complete slip of the proximal femoral epiphysis has been reported as a complication of hip infection , while to the best of our knowledge , the complete separation of the epiphysio - trochanteric nuclei complex has been described only once .
while most partial or complete epiphyseal slip complicating hip infections reported in literature are late presenting , with a delayed or even missed diagnosis and an overall poor functional result with sequestration or destruction of the capital epiphysis , physeal pseudoarthrosis , ankylosis , great limb discrepancy , and need for surgical correction [ 1 , 2 , 8 , 1517 ] , literature describes the extreme resistance to infections of the growing plate , underlining that an epiphyseal slipping complicating neonatal osteomyelitis appears to be consequence of a mechanical loosening and consequent blood supply compromise rather than infective destruction of the growing plate [ 2 , 8 ] .
consequently early correct diagnosis and early appropriate treatment appear to be correlated with good result [ 3 , 12 ] .
reduction and pinning with kirschner wires is generally reported [ 12 , 18 ] . in conclusion , despite the rarity of the association between musculoskeletal septic events and physeal separation , this potential diagnosis has to be considered in the neonatal age .
differential diagnosis at onset is not easy , especially when the newborn is at a very early stage and even the correct localization of the disease could be difficult to identify ( our newborn underwent three surgical procedures before correct localization of the disease was established ) .
standard radiographs in newborns and in small children could be equivocal and in addition it is very important to hold a correct position while performing the exam .
ultrasonography is a valid exam to detect the presence of a fluid collection . in our case
an additional complicating factor was constituted by the misdiagnosis which was based on the lack of a correct preoperative imaging ( mri was not performed and a diagnosis of septic arthritis was formulated ) .
mri appears to be the best diagnostic test which will allow for a detailed view of the joint(s ) involved , thus allowing for a correct diagnosis and therapeutic approach .
finally we underline the excellent long - term results obtained after open drainage and closed reduction with pinning . | ### Summary:
: in newborns physeal separations and septic osteomyelitis or arthritis are unusual , representing a problem in diagnosis and treatment .
therapy needs to be carried out soon in order to prevent anatomical and functional consequences .
association between septic event and physeal separation is rare .
we report a 28-day - old female , admitted for elevated temperature , who underwent three nonorthopaedic surgical procedures before , and orthopaedic evaluation 8 days after admission . after an x - ray and an ultrasonography a septic arthritis with consequent hip dislocation
was supposed . only at the time of surgery a separation between the epiphysio - trochanteric nuclei complex and the femoral shaft
was observed , with clear hip joint .
the interest in this case consists in the difficulty of the differential diagnosis at the first evaluation , the orthopaedic misdiagnosis based on the lack of complete preoperative imaging , and finally the long - term excellent result after a prompt surgical treatment . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: radioactive iodine has been used extensively for treatment of hyperthyroidism for more than 60 years . as it was noticed that the treatment not only alleviated the hyperthyroid state but also caused goitres to shrink , this therapy was introduced more than 20 years ago as a possible treatment modality in the management of non - toxic goitre [ 1 - 6 ] .
the first reports described patients with large multinodular goitres who for other reasons were not eligible for surgery ( for example , patients with cardiac or respiratory failure ) . in one study
, it was stated that the use of radioactive iodine therapy constitutes an alternative to surgery in selected patients with large compressive goitres in whom surgery was contraindicated because of age or other medical conditions .
later , treatment was given to patients with diffuse non - toxic goitre , all of whom had serious symptoms but refused surgery .
the general treatment modalities for non - toxic goitre are medical treatment with levothyroxine , surgery , and radioactive iodine .
thyroxine treatment for diffuse non - toxic goitre is a well - established modality in some countries , especially in iodine - deficient regions where often the disease affects more than 10% of the population .
a reduction in thyroid volume of 20 - 30% within 3 months can be achieved but requires a thyroxine dose that can lead to suppression of serum thyrotropin , tissue thyrotoxicosis , and risk of osteoporosis .
life - long treatment is necessary , yet most patients will develop nodular thyroid disease , for which thyroxine is much less effective .
non - toxic multinodular goitres are more prevalent in populations with low or borderline iodine intake .
the disease most often starts at a young age with a diffuse enlargement that gradually becomes more nodular with time and with increasing numbers of autonomously functioning nodules . at the nodular stage ,
thyroxine therapy is inefficient in reducing thyroid volume since thyrotropin starts to be suppressed by the autonomous nodules , and therefore in most countries surgery has been the only option for therapy .
a fear of increasing the thyroid gland through radiation thyroiditis was allayed by a study by nygaard and colleagues , which demonstrated that the inspiratory flow curve was not negatively affected after treatment and that , on the contrary , there was a beneficial effect .
another aspect has been the occurrence of thyroid autoimmunity with a graves disease - like reaction after radioiodine therapy , in some cases accompanied by thyroid - associated ophthalmopathy .
it has not yet been resolved as to whether this is a de novo autoimmunity ; instead , it might be existing asymptomatic graves disease within a nodular goitre with a transitory deterioration of the autoimmune process due to antigen release after the destructive radiation .
finally , the possibility of a thyroid tumour harboured in a nodular goitre , though rare , must be kept in mind .
the introduction of radioiodine as a treatment modality has advanced the management of these patients on the one hand but has posed some problems on the other hand since many of the populations who were initially low in iodine have now started iodine salt addition programmes , which notoriously lower the uptake of radioiodine .
the treatment success therefore is limited and requires much greater amounts of radioiodine to overcome this problem , thus creating a potential environmental problem due to surplus radioiodine excreted in the urine .
the problem of low iodine uptake has recently been overcome by introducing recombinant human thyroid - stimulating hormone ( rhtsh ) as a stimulator before the radioiodine therapy [ 18 - 20 ] . in one of the studies
, it was shown that , followed by 1.11 gbq , a very low dose of 0.005 mg rhtsh was as safe and effective as 0.1 mg of rhtsh .
other studies have verified that the uptake was dramatically increased , even by low doses of rhtsh , and the regional distribution of the uptake can change substantially , thus providing the possibility for efficient shrinkage of previous large cold nodules by even a single low dose of rhtsh .
subsequent studies have investigated issues such as the amount of rhtsh to be used , the timing , and the effect , even in persons with normal thyroid glands [ 24 - 26 ] . as in radioiodine treatment without pre - stimulation , there have been several reports of thyroid enlargements after rhtsh , and some of these enlargements have been very serious [ 27 - 29 ] . however , the general picture shows a safe procedure with a tendency to relieve local tracheal symptoms .
an alternative to this treatment has been presented as repeated doses of radioiodine rather than pre - stimulation . when used together
although surgeons still advocate surgery as the treatment of choice in non - toxic goitres , it seems clear to most clinicians that radioactive iodine therapy is an attractive alternative with few side effects and is easy for the patient as it does not require hospitalisation .
the limitation of the therapy of having to use either very high or repeated doses of radioiodine due to many large goitres with low iodine uptake has been overcome by pre - treatment with rhtsh [ 18 - 26 ] .
although this treatment at present is rather expensive , it appears that much smaller doses of the drug have sufficient efficacy , and the price therefore should be adjusted by the production of appropriate ampoule sizes . to further document a more widespread use of rhtsh as a pre - treatment ,
additional randomised clinical trials comparing doses of rhtsh and comparing radioiodine therapy with surgery in terms of outcome measures such as efficacy of goitre control , thyroid function , health care costs , and health - related quality of life are needed . only then
can the treatment continue based on solid evidence , which is very likely to change treatment algorithms for non - toxic goitre in the future .
the author has received unrestricted research grants from genzyme ( cambridge , ma , usa ) and has served on one of the advisory boards of the same company . | ### Summary:
: there is no ideal treatment for benign multinodular goitre . besides surgery , which is recommended for large goitres or when malignancy can not be excluded , the non - surgical treatment options are levothyroxine therapy and radioiodine ( 131i ) therapy .
conventional 131i therapy [ without recombinant human thyroid - stimulating hormone ( rhtsh ) ] has been used for more than a decade in symptomatic non - toxic multinodular goitre , and although it does lead to significant thyroid volume reduction , relatively high activities of radioiodine are needed because of a frequent finding of a low thyroid radioiodine uptake .
rhtsh , even when used in very small doses in combination with 131i therapy , enhances the thyroid volume reduction at lower 131i activities by doubling the thyroid radioiodine uptake .
however , before rhtsh stimulation can be routinely used by clinicians to optimise the 131i therapy in multinodular goitre , aspects of this association , such as the cost - benefit and optimum rhtsh dose and safety , will have to be sufficiently clarified . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the ever - increasing demand of healthcare services and the sensitivity of the work at hospitals have increased the levels of job stress on the individuals working in it .
it has been reported that many senior doctors suffer high levels of stress as a result of their work , consequently impairing their health , which in turn affects their ability to provide high quality care to patients .
stressful conditions make health staff in general and doctors in particular susceptible to more physical and emotional morbidity .
professional dissatisfaction , poor work performance , and burnout as the outcome of stress have been reported among physicians .
studies have revealed that the causes of stress among healthcare professionals include : ( a ) emotional and physical needs of patients , pressures to perform consistently and optimally under changing conditions for physicians ; ( b ) inadequate staffing levels ; ( c ) long working hours ; ( d ) exposure to infectious diseases and hazardous substances leading to illness or death ; ( e ) demands of the job and lack of communication ; ( f ) career development ; ( g ) problems with patients ; ( h ) problems with work / home interface and social life ; ( i ) working environment ; and ( j ) workload .
the stressors may be varied in number and type ; nevertheless , one 's physiological , psychological , and social makeup determines the attitudes associated with the stress , making it stimulating and exciting to some , whereas others may feel stressed and burned .
however , the difference in the response of the individuals to similar stressors under similar work conditions and situations may be attributed to the personality of the individual and particularly to the type of the personality .
personality is more or less stable and enduring organization of a person 's characteristics , temperament , intellect , and physique , which determine his / her unique adjustment to the environment .
personality factors have shown inclination toward stress , anxiety , and other occupational health outcomes in different areas of medicines , and these factors may contribute to the perception of job dissatisfaction and stress .
a longitudinal study indicated that personality and learning style of the doctors are correlates of approaches to work , workplace climate , stress , burnout , and satisfaction .
recent research has examined people using extensive lists of personality dimensions and has distilled them into big five . though the big five personality is being extensively used in studying the personality , it remains undeniable fact that the five factors are akin to type a / type b orientation .
famous researchers friedman and rosenman believed that people belong to either of the two basic types of behavior or personality , type a and type b. type a behaviors include being ambitious , competitive , alert , impatient , and aggressive .
they are always in a hurry , to the point of appearing driven , showing chronically high levels of arousal .
they exhibit deadline urgency ( having to get things done by a certain time ) and extreme competitiveness , even in leisure pursuits .
type b personalities may be equally ambitious , but do not appear to be driven . their job ambitions do not dominate their entire lives .
they find time for family and friends , and tend to choose leisure pursuits that are less competitive than type a 's choice .
research studies have reported that doctors with type a personality were inclined to more stress as compared to doctors of type b personality ; however , type a doctors showed slightly better performance than type b ones .
another study discovered that type a personality individuals were compulsive , workaholic , aggressive , and competitive , whereas type b individuals were less aggressive , more relaxed , and set fewer deadlines .
it may have positive aspect in that some individuals may feel challenged and may be able to raise their productivity to meet the increasing demand .
however , the ability of the individual to take stress positively or negatively may be related to the personality type of the individual , which may have its own consequences upon work performance . in a nutshell
, the delivery of high - quality medical care contributes to improved health outcomes of the patients , which may be affected by the psychological and emotional state of the healthcare professionals .
the present study has attempted to study the sources of stress among healthcare professionals and the behavior of the personality types a and b toward stress .
further , the performance of both personality types and the relationship between stress and performance with respect to personality type a and type b healthcare professionals have also been examined .
the following hypotheses were tested : h1 : there shall be significant differences between personality type a and type b for stressful situations .
h2 : there shall be significant differences between personality type a and type b for performance dimensions .
the sample for this study included 160 healthcare professionals of pgi , chandigarh , consisting of nurses , junior residents , senior residents , physiotherapists , and interns .
but some were not returned and a few were incomplete , finally making the sample size of 160 .
the sample consisted of 26% males and 74% females ; 22% were married while 78% were unmarried .
the distribution of the participants according to their age group is as follows : 65% in 1825 years , 25% in 2633 years , 6% in 3441 years , 3% in 4249 years . and
the sample consisted of 30% junior residents , 16% senior residents , 9% physiotherapists , 37% nurses , and 8% interns .
the study was conducted during 20102011 . to achieve the objective of the study , a questionnaire was designed to collect the information from the healthcare professionals . the questionnaire consisted of four parts : a , b , c , and d. part
part b solicited information on the personality type of healthcare professionals , with the bortner 's scale . in the present study , the number of respondents belonging to personality type a was 110 and personality type b was 50 .
part c was framed to identify the sources of stress among healthcare professionals , with stressful situation questionnaire addressing different stressful situations such as relationship with patients , family rejections , identification with patients , deterioration and complication , job criticism , private life , and daily work .
part d elicited the responses of the healthcare professionals on the different criteria of job performance , such as good clinical care , good medical practice , relationship with colleagues , relationship with patients , and teaching and training based on the national health services ( nhs ) professionals survey .
the following hypotheses were tested : h1 : there shall be significant differences between personality type a and type b for stressful situations .
h2 : there shall be significant differences between personality type a and type b for performance dimensions .
the sample for this study included 160 healthcare professionals of pgi , chandigarh , consisting of nurses , junior residents , senior residents , physiotherapists , and interns .
but some were not returned and a few were incomplete , finally making the sample size of 160 .
the sample consisted of 26% males and 74% females ; 22% were married while 78% were unmarried .
the distribution of the participants according to their age group is as follows : 65% in 1825 years , 25% in 2633 years , 6% in 3441 years , 3% in 4249 years . and
the sample consisted of 30% junior residents , 16% senior residents , 9% physiotherapists , 37% nurses , and 8% interns .
to achieve the objective of the study , a questionnaire was designed to collect the information from the healthcare professionals . the questionnaire consisted of four parts : a , b , c , and d. part a was framed to collect personal information of the respondents .
part b solicited information on the personality type of healthcare professionals , with the bortner 's scale . in the present study , the number of respondents belonging to personality type a was 110 and personality type b was 50 .
part c was framed to identify the sources of stress among healthcare professionals , with stressful situation questionnaire addressing different stressful situations such as relationship with patients , family rejections , identification with patients , deterioration and complication , job criticism , private life , and daily work .
part d elicited the responses of the healthcare professionals on the different criteria of job performance , such as good clinical care , good medical practice , relationship with colleagues , relationship with patients , and teaching and training based on the national health services ( nhs ) professionals survey .
identification with the patients ( m = 3.42 ) emerged to be the most stressful situation , followed by deterioration and complication in patient condition ( m = 3.38 ) and job criticism ( m = 3.09 ) , while family rejection ( with mean value m = 2.41 ) was noted to cause least stress among healthcare professionals [ table 1 ] .
sufferings of patients , which these professionals see and face daily ( particularly the severely handicapped patients ) , may cause stress in their minds , the feeling of which lasts even in their off hours of work .
, where dealing with patients pain was noted to be one of the stressors . family rejection has been found to be the least stressor , which indicates that these professionals get enough support , encouragement , and continuous appreciation from their family .
it is evident from the results [ table 2 ] that personality type a individuals obtained higher performance scores ( mean values ) as compared to type b individuals on four stressful situations , which are identification with patients , deterioration and complications , relationship with patients , and private life .
personality type b professionals scored better as compared to personality type a professionals in stressful situations such as job criticism , daily work , and family rejections .
it was also noticed that the mean difference between personality type a and personality type b healthcare professionals was significant for one stressful situation , that is , identification with patients ( t = 2.05 , p < 0.05 ) .
thus , the hypothesis h1 , i.e. , there shall be significant differences between personality type a and type b for stressful situations , may be partially accepted .
mean and standard deviations of stressful situations means , sd , and t values showing differences between personality types in stressful situations both personality type a and personality type b professionals obtained mean values more than average on performance dimensions [ table 3 ] .
further , it is observed that personality type a individuals scored better on majority of the performance factors , with the highest mean obtained for teaching and training ( m = 4.13 ) , followed by relationship with patients ( m = 4.08 ) , relationship with colleagues ( m = 4.05 ) , and good clinical care ( m = 3.89 ) , whereas personality type b individuals showed higher mean value for good medical practice ( m = 3.76 ) [ table 4 ] .
the results further reveal that the effect of personality type showed significant difference in relationship with colleagues ( t = 3.95 , p < 0.01 ) and teaching and training ( t = 3.02 , p < 0.01 ) .
the personality type a healthcare professionals obtained higher total mean than personality type b individuals .
it can be said that that personality type a healthcare professionals perform better than type b professionals .
thus , the hypothesis h2 , i.e. , there shall be significant differences between personality type a and type b for performance dimensions , may be partially accepted .
means , sd , and t values showing differences between personality types on performance dimensions personality type and performance indicators the correlation analysis [ table 4 ] reveals that the stressful situation relationship with patients showed negative and significant correlation with good clinical care ( r = 0.197 , p < 0.05 ) and rapport with patients ( r = 210 , p < 0.01 ) . it can be said that if the healthcare professionals are not able to communicate properly with the patients or if they are unable to build good relationship with the patients , they will not be able to provide good clinical care .
daily work showed negative and significant correlation with good medical practice ( r = 198 , p < 0.05 ) .
hence , if the healthcare professionals become overloaded with work involving frequent interruptions , it may create stress affecting good medical practice .
the findings are similar to a study which reported that due to tiredness , pressure of overwork lowered the standards of medical care . moreover , higher occupancy and overburden may not enable them to add to their medical knowledge upgradation .
the findings also indicate that some of the determinants of stressful situations were negatively correlated with the performance indicators . the results may support the findings of a study where stress in doctors was found to be related to lower quality of clinical supervision .
thus , the hypothesis h3 , i.e. , there is negative relationship between perceived stress among healthcare professionals and performance , may be partially accepted . in case of personality type
a healthcare professionals [ table 5 ] , relationship with patients showed negative significant correlation with good clinical care ( r = 0.220 , p < 0.01 ) and rapport with patients ( r = 236 , p < 0.01 ) .
daily work was negatively and significantly related to good medical practice ( r = 177 , p<0.05 ) . in case of personality type b
healthcare professionals [ table 6 ] , daily work was negatively and significantly related to relationship with colleagues ( r = 505 , p < 0.05 ) and teaching and training ( r = 533 , p < 0.05 ) . deterioration and complications in patient condition showed positive and significant correlation with rapport with patients ( r = 498 , p < 0.05 ) , whereas job criticism was significantly and negatively related to good medical practice ( r = 530 , p < 0.05 ) . conditions and complications of the patient 's ailments seen for a long time and the feeling of suicide by such patients may have sensitized the doctors , nurses , or others for more empathy , rapport , and care for such patients .
however , job criticism was found to be negatively significantly related to good medical practice .
this leads to the impression that the dissatisfaction from job , lesser pay , and limited autonomy in decision making affects the good medical practice and medical knowledge .
daily work was also negatively and significantly related to relationship with colleagues , and teaching and training .
this means that daily routine and the higher occupancy in the work influences the relationship of the professionals with their colleagues , and moreover , reduces their willingness to help the students and colleagues in teaching and training .
correlation values of stressful situations and performance dimensions in personality type a healthcare professionals correlation values of stressful situations and performance dimensions in personality type b healthcare professionals
however , optimal stress always gives individuals an added edge to do their best in challenging situations .
more important is managing and handling stress properly , thereby negating its effect on the performance .
some stress coping strategies like meditation , yoga , exercises , listening to music , spending time with nature , and proper sleep are always helpful in reducing stress .
stress management programs that teach individuals about the nature and sources of stress , the effects of stress on health , and personal skills to reduce stress , for example , time management or relaxation exercises , should be organized .
the authorities need to see and ensure that the workload is within the limits of capabilities and resources of these professionals . cognitive behavioral training can improve the ability to cope with stress over the long term and that the beneficial use of leisure time should be discussed as a part of cognitive behavioral training . | ### Summary:
: background : the present paper has examined the sources of stress among the healthcare professionals and the difference between responses of personality type a and type b healthcare professionals toward stressful situations .
further , the difference in the performance of both the personality types has been studied .
the relationship between stress and performance among the healthcare professionals in general and with respect to personality type a and type b healthcare professionals in particular has also been investigated.methods:a total of 160 healthcare professionals of post graduate institute ( pgi ) , chandigarh , were subjects of this study.results:identification with patients , deterioration and complication in the patient condition , and job criticism emerged to be the sources of stress .
significant difference between personality type a and personality type b professionals response pertaining to identification with the patients only has been reported .
however , type a individuals showed slightly higher inclination as compared to type b individuals on majority of stressful situations .
it was further noted that type a individuals had scored higher on almost all the performance indicators as compared to personality type b individuals .
the mean difference between the personality types was found to be significant for two performance dimensions , i.e. , relationship with colleagues , and teaching and training.conclusions:the stressful situation relationship with patients was found to have significantly negative impact on the performance factors such as good clinical care and rapport with patients .
daily work was also found to be negatively related to good medical practice . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: liver cirrhosis is an end - stage liver disease and common consequence of the long clinical course of all chronic liver diseases .
the disease is most commonly caused by excessive alcohol consumption , hepatitis b and c , fatty liver disease , primary biliary cirrhosis , autoimmune hepatitis , and other rare causes .
taiwan has a high prevalence of hepatitis b , with an overall prevalence of chronic hepatitis b viral infection of 13.7% ( 95% confidence interval [ ci ] = 12.914.5 ) in 2002 .
liver cirrhosis and hepatocellular carcinoma ( hcc ) , which are both closely correlated with hepatitis b , are among the 10 leading causes of death in taiwan .
cancer constitutes an enormous global burden ; according to globocan estimates , approximately 14.1 million new cancer cases and 8.2 million cancer - related deaths occurred worldwide in 2012 .
cancer has been the leading cause of mortality among the general population in taiwan since 1982 ( 6 ) .
hcc is the fifth most common malignancy worldwide and the third most common cause of cancer mortality . in taiwan , hcc was the third most common cancer site and second leading cause of cancer death in 2012 .
liver cirrhosis can evolve into hcc , and the presence of comorbidities , hepatitis b or c , alcohol consumption , and age can influence the terminal event ; thus , liver cirrhosis is considered a step in the progression of hcc .
in addition , cirrhosis , particularly alcoholic cirrhosis , is generally accepted as a risk factor for hcc development .
the relationship between extrahepatic malignancies and cirrhosis has also been explored . a population - based cohort study conducted in denmark found an increased risk of liver and several extrahepatic cancers in patients with cirrhosis .
a study conducted in sweden revealed that the overall risk of non - hcc malignancies ( mostly biliary and gastrointestinal malignancies ) was more than 2-fold greater for patients with cirrhosis than for the general population .
regarding extrahepatic malignancies , some studies have focused on specific cancer sites and revealed higher risks of digestive tract cancers and lymphoproliferative disorders among patients with cirrhosis compared with control populations . to the best of our knowledge
, no study has examined the possible association between nonalcoholic cirrhosis ( nac ) and cancer risk .
thus , we conducted a population - based retrospective cohort study to determine whether patients with nac have an increased risk of overall or site - specific cancer .
the database used was derived from the taiwan national health insurance ( nhi ) program .
the nhi program , from 1996 to 2011 , covered over 99% of the entire population and more than 97% of the health care institutions in taiwan.we used the longitudinal health insurance database 2000 ( lhid2000 ) as the data source for our study .
the lhid2000 , administered by the national health research institutes ( nhri ) , contains the data from 1996 to 2011 of 1 million randomly sampled beneficiaries enrolled in the nhi . to protect patient privacy ,
all personal identification numbers were encrypted by the nhri before the lhid 2000 was released .
all diagnoses were made using the international classification of diseases , ninth revision , clinical modification ( icd-9-cm ) .
our study was approved by the ethics review board of china medical university ( cmu - rec-101012 ) .
we identified patients aged 20 years and older who had received an nac diagnosis ( icd-9-cm codes 571.5 and 571.6 ) as the nac cohort and set the diagnosis date as the index date .
the exclusion criteria were an age less than 20 years , history of cancer ( icd-9-cm codes 140208 ) before the index date , and history of alcoholic cirrhosis or chronic hepatitis ( icd-9-cm codes 571.0571.6 , 571.8 , and 571.9 ) during follow - up .
for each nac case , 4 patients without a history of cirrhosis ( icd-9-cm code 571 ) were identified as the non - nac cohort and frequency - matched according to age , sex , and index year by using the same exclusion criteria .
cancer ( icd-9-cm codes 140195 and 200208 ) diagnoses were identified from the registry for catastrophic illness patient database .
all the patients in this study were followed from the index date until cancer diagnosis , withdrawal from the nhi , or the end of 2011 .
the pre - existing comorbidities and cancer - related examinations were defined as long as they existed prior to the endpoint .
the comorbidities in this study included hypertension ( icd-9-cm codes 401405 ) , diabetes ( icd-9-cm code 250 ) , hyperlipidemia ( icd-9-cm code 272 ) , obesity ( icd-9-cm code 278 ) , hepatitis b ( icd-9-cm codes v02.61 , 070.20 , 070.22 , 070.30 , and 070.32 ) , hepatitis c ( icd-9-cm codes v02.62 , 070.41 , 070.44 , 070.51 , and 070.54 ) , and colon polyp ( icd-9-cm codes 211.3 ) .
in addition , we considered cancer - related examinations , including esophagogastroduodenoscopy ( icd-9-op procedure code 45.13 and 45.16 ) , colonoscopy ( icd-9-op procedure code 45.23 ) , abdomen ct ( icd-9-op procedure code 88.01 and 88.02 ) , and abdomen ultrasonography ( icd-9-op procedure code 45.13 and 88.76 ) .
the distribution of age , sex , and comorbidities was expressed as a frequency or mean standard deviation ( sd ) .
the categorical variables were analyzed using a chi - square test and the continuous variables were analyzed using a student t test .
the incidence densities were calculated according to age , sex , comorbidity , and cancer type for each cohort .
univariate and multivariate cox proportional hazards regression models were used to estimate the hazard ratios ( hrs ) and 95% cis for cancer in patients with nac compared with those without nac .
the multivariate models were simultaneously adjusted for age , sex , and the comorbidities of hypertension , diabetes , hyperlipidemia , obesity , hepatitis b and c , and colon polyp , and diagnostic procedures of esophagogastroduodenoscopy , colonoscopy , abdomen ct , and abdomen ultrasonography . all data processing and statistical analyses were performed using sas version 9.4 ( sas institute , inc
. , cary , nc , usa ) . a 2-tailed p value of < 0.05 was considered statistically significant .
the nhi program , from 1996 to 2011 , covered over 99% of the entire population and more than 97% of the health care institutions in taiwan.we used the longitudinal health insurance database 2000 ( lhid2000 ) as the data source for our study .
the lhid2000 , administered by the national health research institutes ( nhri ) , contains the data from 1996 to 2011 of 1 million randomly sampled beneficiaries enrolled in the nhi . to protect patient privacy ,
all personal identification numbers were encrypted by the nhri before the lhid 2000 was released .
all diagnoses were made using the international classification of diseases , ninth revision , clinical modification ( icd-9-cm ) .
our study was approved by the ethics review board of china medical university ( cmu - rec-101012 ) .
we identified patients aged 20 years and older who had received an nac diagnosis ( icd-9-cm codes 571.5 and 571.6 ) as the nac cohort and set the diagnosis date as the index date .
the exclusion criteria were an age less than 20 years , history of cancer ( icd-9-cm codes 140208 ) before the index date , and history of alcoholic cirrhosis or chronic hepatitis ( icd-9-cm codes 571.0571.6 , 571.8 , and 571.9 ) during follow - up .
for each nac case , 4 patients without a history of cirrhosis ( icd-9-cm code 571 ) were identified as the non - nac cohort and frequency - matched according to age , sex , and index year by using the same exclusion criteria .
cancer ( icd-9-cm codes 140195 and 200208 ) diagnoses were identified from the registry for catastrophic illness patient database .
all the patients in this study were followed from the index date until cancer diagnosis , withdrawal from the nhi , or the end of 2011 .
the pre - existing comorbidities and cancer - related examinations were defined as long as they existed prior to the endpoint .
the comorbidities in this study included hypertension ( icd-9-cm codes 401405 ) , diabetes ( icd-9-cm code 250 ) , hyperlipidemia ( icd-9-cm code 272 ) , obesity ( icd-9-cm code 278 ) , hepatitis b ( icd-9-cm codes v02.61 , 070.20 , 070.22 , 070.30 , and 070.32 ) , hepatitis c ( icd-9-cm codes v02.62 , 070.41 , 070.44 , 070.51 , and 070.54 ) , and colon polyp ( icd-9-cm codes 211.3 ) .
in addition , we considered cancer - related examinations , including esophagogastroduodenoscopy ( icd-9-op procedure code 45.13 and 45.16 ) , colonoscopy ( icd-9-op procedure code 45.23 ) , abdomen ct ( icd-9-op procedure code 88.01 and 88.02 ) , and abdomen ultrasonography ( icd-9-op procedure code 45.13 and 88.76 ) . ascites ( icd-9-cm codes 789.5 ) was considered a severity of liver cirrhosis .
the distribution of age , sex , and comorbidities was expressed as a frequency or mean standard deviation ( sd ) .
the categorical variables were analyzed using a chi - square test and the continuous variables were analyzed using a student t test .
the incidence densities were calculated according to age , sex , comorbidity , and cancer type for each cohort .
univariate and multivariate cox proportional hazards regression models were used to estimate the hazard ratios ( hrs ) and 95% cis for cancer in patients with nac compared with those without nac .
the multivariate models were simultaneously adjusted for age , sex , and the comorbidities of hypertension , diabetes , hyperlipidemia , obesity , hepatitis b and c , and colon polyp , and diagnostic procedures of esophagogastroduodenoscopy , colonoscopy , abdomen ct , and abdomen ultrasonography .
all data processing and statistical analyses were performed using sas version 9.4 ( sas institute , inc . ,
cary , nc , usa ) . a 2-tailed p value of < 0.05 was considered statistically significant .
this study comprised 2109 patients with nac and 8436 patients without cirrhosis for data analysis ( table 1 ) .
as expected , both cohorts exhibited similar distributions of age and sex ; most patients were aged 65 years or older ( 44.8% ) and were male ( 62.3% ) .
the mean ages of the nac and non - nac cohorts were 61.3 16.2 and 60.6 16.4 years , respectively .
the nac cohort showed a higher prevalence of comorbidity than did the non - nac cohort , except of hyperlipidemia .
patients in the nac cohort were likely to have esophagogastroduodenoscopy , colonoscopy , abdomen ct , and abdomen ultrasonography .
comparison of demographics and comorbidity between cirrhosis patients and controls the mean follow - up durations were 3.62 years ( sd = 3.75 ) and 6.13 years ( sd = 3.43 ) for the nac and non - nac cohorts , respectively ( data not shown ) . in total , 534 patients in the nac cohort received cancer diagnoses , an incidence of 69.9 per 1000 person - years ; 439 patients in the non - nac cohort received cancer diagnoses , an incidence of 8.49 per 1000 person - years , yielding a crude hr of 7.03 ( 95% ci = 6.197.98 ) ( table 2 ) .
after adjustment for age , sex , and the comorbidities of hypertension , diabetes , hyperlipidemia , obesity , hepatitis b and c , and colon polyp , and diagnostic procedures of esophagogastroduodenoscopy , colonoscopy , abdomen ct , and abdomen ultrasonography , the risk of developing cancer was significantly higher for patients with nac than for those without nac ( adjusted hr [ ahr ] = 6.21 ; 95% ci = 5.367.18 ) .
the incidence and risk of cancer , as stratified according to age , sex , and comorbidity , were higher in patients with nac than in those without nac .
comparisons of incidence densities and hazard ratio of cancer by study cohorts table 3 presents the results of analyses of the cancer type differences between the nac and non - nac cohorts .
the nac cohort exhibited a significantly higher risk of hematologic malignancy ( ahr = 3.12 , 95% ci = 1.347.25 ) , esophagus cancer ( ahr = 7.25 , 95% ci = 2.4421.6 ) , stomach cancer ( ahr = 5.50 , 95% ci = 2.7810.9 ) , colorectal cancer ( ahr = 2.58 , 95% ci = 1.594.18 ) , hcc ( ahr = 122.7 , 95% ci = 68.4220.1 ) , and cholangiocarcinoma ( ahr = 5.10 , 95% ci = 1.5217.1 ) , compared with the non - nac cohort . comparison of incidence and hazard ratio of subdivision cancer according to cirrhosis status the men with nac exhibited a significantly higher risk of hematologic malignancies , digestive tract cancers , hcc , cholangiocarcinoma , and nondigestive tract cancers compared with the men without nac ( table 4 ) .
the women with nac had significantly 3.54- and 86.0-fold higher risks of digestive tract cancers and hcc , respectively , compared with the women without nac . among the patients aged 59 years
, those with nac were at higher risk of digestive tract cancers , hcc , and nondigestive tract cancers compared with those without nac ( table 5 ) . among the patients aged 60 years , those with nac were at higher risk of hematologic malignancies , digestive tract cancers , hcc , cholangiocarcinoma , and nondigestive tract cancers compared with those without nac .
furthermore , the ahrs for cancer types was stratified according to follow - up duration ( table 6 ) . among the patients with a follow - up duration 1 year , those with nac exhibited a significantly higher risk of digestive tract cancer and hcc compared with those without nac . however , among the patients with a follow - up duration > 1 year , patients with nac had a 21.0-fold significantly higher risk of hcc and a 1.89-fold marginally significantly higher risk of nondigestive tract cancers compared with those without nac . cox model with hazard ratios and 95% confidence intervals of subdivision cancer associated with cirrhosis stratified by sex cox model with hazard ratios and 95% confidence intervals of subdivision cancer associated with cirrhosis stratified by age cox model with hazard ratios and 95% confidence intervals of subdivision cancer associated with cirrhosis stratified by follow - up duration stratified analysis by ascites status among nac patients shows that nac patients with ascites typically had higher ahrs of cancer when compared with nac patients without ascites , except for cholangiocarcinoma and nondigestive tract cancers .
when compared with control group , nac with ascites exhibited a higher risk of all cancer ( ahr = 7.93 , 95% ci = 6.0810.4 ) , hematologic malignancies ( ahr = 5.84 , 95% ci = 1.1829.0 ) , digestive tract cancers ( ahr = 4.92 , 95% ci = 2.3010.5 ) , and hcc ( ahr = 148.3 ,
95% ci = 78.8279.0 ) compared with those without nac ( table 7 ) .
this nationwide population - based cohort study highlighted that the overall cancer risk was significantly higher in the nac group compared with the non - nac group , and cancer site - specific analysis revealed that the nac cohort had a markedly higher risk of hcc development than did the control cohort
. significantly higher risks of most digestive tract cancers and hematological malignancies were observed in the nac group .
further analysis stratified according to sex , age , and follow - up duration demonstrated different patterns among the cancer types .
the cancer burden in taiwan has been a concern for the government , which has inspirited several prevention programs for certain major cancers , such as education of the general population to avoid high - risk factors of cancer and receive periodical cancer screening , and has aimed at decreasing cancer incidence and mortality rates .
consequently , more population - based research in the field of cancer - prevention epidemiology , such as the current study of cancer risk among patients with nac , continues to be conducted .
sorensen et al conducted a nationwide cohort study to investigate the risks of hcc and other cancers in patients with cirrhosis in denmark , determining that the risk of hcc was exceptionally high ( standardized incidence ratio = 36 , 95% ci = 3241 ) .
a similar phenomenon has been observed by other researchers , and this finding is consistent with our data , which indicated a markedly higher risk of hcc among patients with nac than among those without nac ( ahr = 122.7 , 95% ci = 68.4220.1 ) .
liver cirrhosis has long been regarded as the most critical premalignant lesion of hcc , and research has established that liver cirrhosis is a substantial determinant for hcc development , regardless of the presence of alcohol cirrhosis or nac . except for hematologic malignancy ,
the cancer sites with a significantly higher risk among the patients with nac in our study were exclusively digestive tract cancers ( except for pancreatic cancer ) ( table 3 ) .
randi et al evaluated the possible association between cirrhosis and digestive tract neoplasms and found that cirrhotic patients had an increased risk of oral , pharyngeal , and esophageal cancers .
randi et al indicated that the excessive risk found for upper digestive tract cancers may be partially due to a residual confounding of alcohol consumption and tobacco use .
in the present study , we excluded patients with alcoholic cirrhosis and still found an association between risk of digestive tract cancers and nac .
zullo et al highlighted a significant 2.6-fold ( p < 0.01 ) higher prevalence of gastric cancer than that expected in patients with cirrhosis .
a previous study mentioned cirrhosis as an independent risk factor for colonic adenomas , which may contribute to the relationship between hcc and colorectal cancer .
lombardo et al suggested that liver cirrhosis might be considered an immunological disturbance that increases the risk of developing lymphoproliferative disorders ; such a suggestion is in agreement with our results showing a significantly higher risk of hematologic malignancy in the nac group than in the control group .
because of the relatively few cases related to each cancer site investigated in this study , the risk estimates were unstable and the power was inadequate for stratified analysis .
therefore , we pooled our patients with cancers other than hematologic malignancy , hcc , or cholangiocarcinoma and categorized such patients into those with digestive tract and nondigestive tract cancers for further analyses stratified according to sex , age , and follow - up duration .
we revealed that both men and patients aged 60 years who had cirrhosis exhibited consistently higher risks among all cancer types .
it is difficult to figure out the reasons to explain the differences that emerge from these stratified analyses .
one possible explanation is that these 2 groups comprised more patients than did their counterparts , increasing the likelihood of yielding a significantly different risk estimate .
men patients with nac had higher risks for all cancer types ; on the other hand , women patients with nac only had significantly higher risks for hcc and digestive tract cancers .
although less women cases of nac , we assume that women patients tend to be amenable for further gastrointestinal tract examinations after diagnosis of nac , which may increase the opportunity to detect digestive tract cancers . in general , older people are more prone to developing cancer , and we assume that any risk factor ( eg , nac ) may trigger the cancer development process .
the risk of hcc was most pronounced during early follow - up ( 1 year ; ahr = 206.6 ; 95% ci = 28.91477.3 ) compared with late follow - up , a finding that is in accordance with that of sorensen et al .
in addition , the risk of digestive tract cancers among the patients with nac was more prominent during early follow - up .
we assume that patients with nac might have received clinical checkups at gastrointestinal departments more frequently after nac diagnosis , increasing the likelihood of digestive tract malignancies being detected during early follow - up .
although we adjusted the relative gastrointestinal diagnostic procedures , the residual confounding may still exist . because other factors of child - pugh score are not available in the dataset , we only used ascites to assess the severity of hcc .
nac patients with ascites tend to have higher ahrs of subsequent cancer development compared with nac patients without ascites , and it may partially contribute to the relatively poor prognosis of nac patients with ascites . in our multivariate analyses , we eliminated possible confounding effects by adjusting for comorbidities including hypertension , diabetes , hyperlipidemia , obesity , colon polyp , and hepatitis b and c. all these factors have been suggested as possibly related to cancer or cirrhosis risk .
nac was defined as icd-9-cm codes 571.5 ( cirrhosis of liver without mention of alcohol ) and 571.6 ( biliary cirrhosis ) .
the diagnosis of nac was included heterogeneous causes of liver cirrhosis especially including biliary cirrhosis .
it was known that significant differences of characteristics and outcomes between viral hepatitis - related cirrhosis and nonalcoholic steatohepatitis ( nash)-related cirrhosis , and cirrhosis due to nash is associated with a lower rate of development of hcc compared with viral hepatitis - related cirrhosis .
, this study did not specify the different causes of cirrhosis for further sophisticated analyses because we could not differentiate the diagnosis of nash - related cirrhosis or viral hepatitis - related cirrhosis in the nhird .
the current study demonstrates the generalizability and high follow - up compliance strengths of population - based nationwide database sources .
first , surveillance bias may have contributed to the association observed between nac and digestive tract cancers , although we tried to adjust some examinations . as mentioned , patients with nac likely receive more clinical checkups than does the general population , providing them with more opportunities for detecting cancer , particularly cancers affecting the gastrointestinal tract ( which nac also affects ) , and hematologic malignancy in cirrhotic patients more tended to receive blood tests as more hospital stay in cirrhotic patients is expected .
people with cirrhosis may not declare being an alcoholist because of shame or social stigma , which would lead to their cirrhosis being erroneously classified as nonalcoholic , and it may induce an overestimated cancer risk of nac . however , this problem can not be fixed and it is difficult to exactly assess its effect on the risk analysis .
third , the lhid2000 does not contain information regarding patient lifestyle or behavior ; thus , we could not adjust for factors such as alcohol consumption , smoking history , and diet .
these unhealthy habits can increase the risk of cancer and liver diseases such as cirrhosis .
although we restricted our cases to nac in our analysis , the uncontrolled lifestyle factors and the residual confounding of alcohol consumption might have distorted the results .
therefore , the relatively lower rate of examinations may not reflect the actual situation and we can not accurately identify patients with regular surveillance from nhird to see if they have a better chance to detect digestive tract cancer . despite the limitations of the administrative data , the information regarding nac and cancer diagnosis was highly reliable . in summary ,
the overall cancer incidence among patients with nac in taiwan was significantly higher than among the general population .
apart from hcc , the patients with nac also exhibited higher risks of developing most digestive tract cancers and hematologic malignancies .
the association could be partially due to surveillance bias ( although we have tried to eliminate it by adjusting some diagnostic procedures ) and possibly an immunological disturbance of cirrhosis ; however , the underlying mechanisms require further comprehensive investigation . | ### Summary:
: abstractalcoholic cirrhosis is generally accepted as a risk factor for hepatocellular carcinoma ( hcc ) development ; however , little research has examined the relationship between nonalcoholic cirrhosis ( nac ) and hcc .
thus , the aim of this study was to investigate whether nac is associated with the risk of hcc and extrahepatic malignancies in taiwan.we conducted a populated - based retrospective cohort study by using data from the taiwan national health insurance ( nhi ) program .
a total of 2109 patients with nac were identified from the nhi database between 2000 and 2011 . for a control group ,
4 patients without nac were frequency - matched with each nac patient according to sex , age , and index year .
we used cox proportional hazards regression analysis to calculate adjusted hazard ratios ( ahrs ) and 95% confidence intervals ( cis ) and determine the effects of nac on cancer risk.the overall cancer risk was significantly higher in patients with nac compared with those without nac , and this association was consistent among age , sex , and comorbidity groups .
the risk of developing hcc was remarkably high in the nac group compared with in the control cohort ( ahr = 122.7 , 95% ci = 68.4220.1 ) ; significantly higher risks of extrahepatic malignancies were observed in patients with digestive tract cancers and hematological malignancies .
further analyses stratified according sex , age , and follow - up duration revealed various patterns among the cancer types.the results indicate that patients with nac in taiwan have higher risks of hcc , digestive tract cancers , and hematological malignancies . |
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: as downregulation of car expression has been observed in association with calcification of vascular smooth muscle cells ( vsmc ) in vitro and in human atherosclerotic - calcified arteries , several groups of authors have assessed the effect of calcimimetics on the progression of vascular calcification in vsmc in vitro and in animal models with ckd in vivo .
the calcimimetics r-568 and calindol have been shown to decrease vsmc calcification induced by high phosphate concentrations in culture medium .
the mechanism behind the inhibitory effect of calcimimetics on vascular calcification could be a stimulation of matrix - gla protein ( mgp ) production by vsmc , as initially suggested by farzaneh - far et al . and subsequently supported by observations of others in rat and bovine vsmcs , respectively .
however , in vitro activation of car by r-568 did not modify phosphate - enhanced mgp release in our experimental human vsmc model .
these apparent discrepancies may be due to the use of vsmc from different species , with possibly variable induction of bone morphogenic protein-2 ( bmp-2 ) which is itself a regulator of mgp synthesis and may decrease mgp expression . of interest , in the study by ciceri et al .
using bovine vsmc , increased expression of bmp-2 under high medium phosphate conditions was effectively prevented by calindol .
another possibility of the apparently inconsistent findings is that in none of these in vitro studies the state of gamma - glutamyl carboxylation and phosphorylation of the mgp molecule was assessed .
undercarboxylated and nonphosphorylated mgp , but not fully carboxylated and phosphorylated mgp , was found to correlate with vascular calcification in the clinical setting of patients with ckd .
studies in different animal models of ckd showed an inhibitory effect of the calcimimetics amg 641 or cinacalcet on the progression of vascular calcification in rats and of the calcimimetic r-568 in mice , respectively . whereas in uremic rats vascular calcification was induced either by pharmacological doses of calcitriol or paricalcitol or by feeding high doses of adenine , in our apolipoprotein e ( apoe)-deficient mouse model with superimposed uremia aortic calcification occurred spontaneously , both in media and in atherosclerotic intima ( figure 1 ) .
one of the possible mechanisms of action clearly is suppression of parathyroid overfunction , together with a decrease in serum calcium and phosphate concentrations .
this is in line with the observation that surgical parathyroidectomy led to a similar reduction in vascular calcification in an experimental model of high - dose calcitriol - induced arterial mineralization .
the parathyroid hormone ( pth)-dependent effect does , however , not preclude other mechanisms , including the abovementioned direct effects on the vessel wall . in recent clinical studies ,
the administration of cinacalcet led to a decrease in circulating fibroblast growth factor 23 ( fgf23 ) concentration , whereas vitamin d and/or its active derivatives generally increased it .
however , such an effect of calcimimetics on serum fgf23 was not observed in two recent animal studies .
whether fgf23 favors the occurrence or progression of vascular calcification or not remains an unsolved issue , in contrast to the well - established negative effects of high fgf23 on cardiac structure and function .
notably , the administration of calcimimetics also exerted favorable actions on uremia - induced arterial remodeling in rats with ckd , together with a decrease in the vascular expression of bmp-2 and a reduction in osteoblastic transdifferentiation of vsmc , and reduced the progression of atherosclerosis in apoe - deficient mice with ckd ( figure 2 ) .
most interestingly , lopez et al . were able to demonstrate in their rat model with ckd and arterial calcification induced by high - dose calcitriol treatment that survival was significantly reduced in the animals treated with this most active vitamin d derivative , whereas survival was improved in the animals concomitantly treated with the calcimimetic amg 641 .
recently , a novel peptide , amg 416 ( formerly kai-4169 and now named velcalcetide in the united states ) , has been identified that acts as a car agonist .
it acts by a mechanism distinct from that of cinacalcet , the only approved calcimimetic in clinical practice , as it can activate car both in the presence and the absence of physiological levels of extracellular ca .
this new car agonist has also been shown to reduce the progression of vascular calcification in uremic rats ( surgical 5/6 nephrectomy model ) , in addition to a potent inhibitory effect on pth secretion .
the calcimimetics r-568 and calindol have been shown to decrease vsmc calcification induced by high phosphate concentrations in culture medium .
the mechanism behind the inhibitory effect of calcimimetics on vascular calcification could be a stimulation of matrix - gla protein ( mgp ) production by vsmc , as initially suggested by farzaneh - far et al . and subsequently supported by observations of others in rat and bovine vsmcs , respectively .
however , in vitro activation of car by r-568 did not modify phosphate - enhanced mgp release in our experimental human vsmc model .
these apparent discrepancies may be due to the use of vsmc from different species , with possibly variable induction of bone morphogenic protein-2 ( bmp-2 ) which is itself a regulator of mgp synthesis and may decrease mgp expression . of interest , in the study by ciceri et al .
using bovine vsmc , increased expression of bmp-2 under high medium phosphate conditions was effectively prevented by calindol .
another possibility of the apparently inconsistent findings is that in none of these in vitro studies the state of gamma - glutamyl carboxylation and phosphorylation of the mgp molecule was assessed .
undercarboxylated and nonphosphorylated mgp , but not fully carboxylated and phosphorylated mgp , was found to correlate with vascular calcification in the clinical setting of patients with ckd .
studies in different animal models of ckd showed an inhibitory effect of the calcimimetics amg 641 or cinacalcet on the progression of vascular calcification in rats and of the calcimimetic r-568 in mice , respectively . whereas in uremic rats vascular calcification was induced either by pharmacological doses of calcitriol or paricalcitol or by feeding high doses of adenine , in our apolipoprotein e ( apoe)-deficient mouse model with
superimposed uremia aortic calcification occurred spontaneously , both in media and in atherosclerotic intima ( figure 1 ) .
one of the possible mechanisms of action clearly is suppression of parathyroid overfunction , together with a decrease in serum calcium and phosphate concentrations .
this is in line with the observation that surgical parathyroidectomy led to a similar reduction in vascular calcification in an experimental model of high - dose calcitriol - induced arterial mineralization .
the parathyroid hormone ( pth)-dependent effect does , however , not preclude other mechanisms , including the abovementioned direct effects on the vessel wall . in recent clinical studies ,
the administration of cinacalcet led to a decrease in circulating fibroblast growth factor 23 ( fgf23 ) concentration , whereas vitamin d and/or its active derivatives generally increased it .
however , such an effect of calcimimetics on serum fgf23 was not observed in two recent animal studies . whether fgf23 favors the occurrence or progression of vascular calcification or not remains an unsolved issue , in contrast to the well - established negative effects of high fgf23 on cardiac structure and function .
notably , the administration of calcimimetics also exerted favorable actions on uremia - induced arterial remodeling in rats with ckd , together with a decrease in the vascular expression of bmp-2 and a reduction in osteoblastic transdifferentiation of vsmc , and reduced the progression of atherosclerosis in apoe - deficient mice with ckd ( figure 2 ) .
most interestingly , lopez et al . were able to demonstrate in their rat model with ckd and arterial calcification induced by high - dose calcitriol treatment that survival was significantly reduced in the animals treated with this most active vitamin d derivative , whereas survival was improved in the animals concomitantly treated with the calcimimetic amg 641 .
recently , a novel peptide , amg 416 ( formerly kai-4169 and now named velcalcetide in the united states ) , has been identified that acts as a car agonist .
it acts by a mechanism distinct from that of cinacalcet , the only approved calcimimetic in clinical practice , as it can activate car both in the presence and the absence of physiological levels of extracellular ca .
this new car agonist has also been shown to reduce the progression of vascular calcification in uremic rats ( surgical 5/6 nephrectomy model ) , in addition to a potent inhibitory effect on pth secretion .
block et al . tested the question whether prescription of the calcimimetic cinacalcet to hemodialysis patients with secondary hyperparathyroidism improved their survival .
they prospectively collected data on chronic hemodialysis patients from a large provider in the united states beginning in 2004 , a time coincident with the commercial availability of cinacalcet hydrochloride .
they merged this information with data in the us renal data system to determine all - cause and cardiovascular mortality .
all patients included in the study received intravenous treatment with active vitamin d derivatives , which was considered as a surrogate for the diagnosis of parathyroid overfunction .
of the 19,186 patients , 5976 received cinacalcet and all were followed for up to 26 months .
they used unadjusted and adjusted time - dependent cox proportional hazards modeling to analyze the data .
they found that all - cause and cardiovascular mortality rates were significantly lower for the hemodialysis patients treated with cinacalcet than for those who did not receive calcimimetic treatment .
thus this observational study found a significant survival benefit associated with cinacalcet prescription in patients receiving intravenous vitamin d. however , the study had several limitations , the most important one being the possibility that residual confounding by indication might be responsible for the findings . clearly , observational studies such as this one can not establish a cause - and - effect relationship ; they are only hypothesis generating .
the first large - scale trial of cinacalcet therapy was reported in 2004 in 741 adults with ckd stage 5d .
it assessed treatment efficacy based on intact pth concentrations . between 2004 and early 2012 , 11 additional trials were reported , although none was primarily designed to evaluate treatment effects on patient - relevant outcomes , including mortality or adverse events . in 2011 , raggi et al .
reported the results of the advance study whose objective was to examine whether in chronic hemodialysis patients the administration of cinacalcet plus low - dose vitamin d sterols was superior to flexible doses of vitamin d sterols alone in slowing the progression of vascular and valvular calcification .
eligible subjects were on hemodialysis for 3 months with serum pth values > 300 pg / ml or serum pth values of 150300 pg / ml together with a calcium phosphorus product > 50 mg / dl while receiving vitamin d. all subjects received calcium - based phosphate binders .
coronary artery calcification ( cac ) and aorta and cardiac valve calcium scores were determined both by agatston scoring and the more recently developed volume scoring using multi - detector computed tomography .
subjects with agatston cac scores 30 were randomized to cinacalcet ( 30180 mg / day ) plus low - dose calcitriol or vitamin d analog ( 2 g paricalcitol equivalent / dialysis ) or flexible vitamin d therapy .
the primary end point was percentage change in agatston cac score from baseline to week 52 .
median agatston cac scores increased 24% in the cinacalcet group and 31% in the flexible vitamin d group ( p=0.073 ) .
increases in calcification scores were consistently less in the aorta , aortic valve , and mitral valve among subjects treated with cinacalcet plus low - dose vitamin d sterols , and the differences between groups were significant at the aortic valve .
the authors concluded that in hemodialysis patients with moderate - to - severe secondary hyperparathyroidism , cinacalcet plus low - dose vitamin d sterols may attenuate vascular and cardiac valve calcification . in late 2012 , chertow et al . reported the evaluation of cinacalcet therapy to lower cardiovascular events ( evolve ) trial in 3883 patients receiving long - term hemodialysis treatment .
it was the first trial specifically designed to evaluate cinacalcet treatment plus standard of care versus placebo plus standard of care on patient - centered outcomes , using a primary composite outcome of all - cause mortality or first nonfatal cardiovascular event ( myocardial infarction , myocardial ischemia , heart failure , or peripheral vascular event ) .
secondary end points were cardiovascular mortality , stroke , clinical bone fracture , parathyroidectomy , and components of composite primary end point .
the trial was event driven , requiring 1882 primary end point events for study termination .
its duration had to be extended by 16 months beyond the initially planned 4 years because of lower event rates than anticipated .
the primary analysis was performed on the basis of the intention - to - treat ( itt ) principle .
prespecified secondary analyses included multivariable analyses adjusting for baseline characteristics , and companion analyses with lag censoring , in which data were censored 6 months after patients stopped using a study drug .
the median duration of study drug exposure was 21.2 months in the cinacalcet group versus 17.5 months in the placebo group .
there was a high number of study drug discontinuation by non - protocol - specified reasons in the placebo group , much higher than anticipated , with 20% of patients in that group receiving commercial cinacalcet before the occurrence of a primary event .
this high drop - in rate and other factors limited the statistical power of the trial such that , in contrast to the original assumption of a 20% treatment effect , with the observed study duration and observed rates of events , drop - outs , and drop - ins the re - estimated statistical power was only 54% . the primary composite end point in the evolve trial
was reached in 938 of 1948 patients ( 48.2% ) in the cinacalcet group and in 952 of 1935 patients ( 49.2% ) in the placebo group , stratified according to country and diabetes status ( relative hazard in the cinacalcet group vs. the placebo group , 0.93 ; 95% confidence interval , 0.851.02 , p=0.11 ) .
thus there was a 7% nonsignificant reduction in the risk of the primary composite end point with cinacalcet in the itt analysis .
after adjustment for baseline characteristics , there was a nominally significant 12% reduction in risk .
although analyses accounting for study drug exposure are subject to chance , bias , and confounding , there were consistent ( and nominally significant ) effects , up to a 15% reduction in the primary composite end point and a 17% reduction in mortality , using the abovementioned prespecified secondary analyses .
as to side effects , hypocalcemia and gastrointestinal adverse events were significantly more frequent in patients receiving cinacalcet , as already reported in the first large cinacalcet trial in 2004 .
thus evolve did not meet its primary end point in the unadjusted itt analysis , although it showed a 7% reduction in the risk of death or cardiovascular events with cinacalcet in hemodialysis patients treated for secondary hyperparathyroidism .
itt analyses adjusted for baseline characteristics suggest that treating secondary hyperparathyroidism with cinacalcet results in nominally significant reductions in the risk of death or cardiovascular events . an analysis censoring data after study drug discontinuation suggests a reduced risk with cinacalcet .
block et al . tested the question whether prescription of the calcimimetic cinacalcet to hemodialysis patients with secondary hyperparathyroidism improved their survival .
they prospectively collected data on chronic hemodialysis patients from a large provider in the united states beginning in 2004 , a time coincident with the commercial availability of cinacalcet hydrochloride .
they merged this information with data in the us renal data system to determine all - cause and cardiovascular mortality .
all patients included in the study received intravenous treatment with active vitamin d derivatives , which was considered as a surrogate for the diagnosis of parathyroid overfunction .
of the 19,186 patients , 5976 received cinacalcet and all were followed for up to 26 months .
they used unadjusted and adjusted time - dependent cox proportional hazards modeling to analyze the data .
they found that all - cause and cardiovascular mortality rates were significantly lower for the hemodialysis patients treated with cinacalcet than for those who did not receive calcimimetic treatment .
thus this observational study found a significant survival benefit associated with cinacalcet prescription in patients receiving intravenous vitamin d. however , the study had several limitations , the most important one being the possibility that residual confounding by indication might be responsible for the findings
. clearly , observational studies such as this one can not establish a cause - and - effect relationship ; they are only hypothesis generating .
the first large - scale trial of cinacalcet therapy was reported in 2004 in 741 adults with ckd stage 5d .
it assessed treatment efficacy based on intact pth concentrations . between 2004 and early 2012 , 11 additional trials were reported , although none was primarily designed to evaluate treatment effects on patient - relevant outcomes , including mortality or adverse events . in 2011 , raggi et al .
reported the results of the advance study whose objective was to examine whether in chronic hemodialysis patients the administration of cinacalcet plus low - dose vitamin d sterols was superior to flexible doses of vitamin d sterols alone in slowing the progression of vascular and valvular calcification .
eligible subjects were on hemodialysis for 3 months with serum pth values > 300 pg / ml or serum pth values of 150300 pg / ml together with a calcium phosphorus product > 50 mg / dl while receiving vitamin d. all subjects received calcium - based phosphate binders .
coronary artery calcification ( cac ) and aorta and cardiac valve calcium scores were determined both by agatston scoring and the more recently developed volume scoring using multi - detector computed tomography .
subjects with agatston cac scores 30 were randomized to cinacalcet ( 30180 mg / day ) plus low - dose calcitriol or vitamin d analog ( 2 g paricalcitol equivalent / dialysis ) or flexible vitamin d therapy .
the primary end point was percentage change in agatston cac score from baseline to week 52 .
median agatston cac scores increased 24% in the cinacalcet group and 31% in the flexible vitamin d group ( p=0.073 ) .
increases in calcification scores were consistently less in the aorta , aortic valve , and mitral valve among subjects treated with cinacalcet plus low - dose vitamin d sterols , and the differences between groups were significant at the aortic valve .
the authors concluded that in hemodialysis patients with moderate - to - severe secondary hyperparathyroidism , cinacalcet plus low - dose vitamin d sterols may attenuate vascular and cardiac valve calcification . in late 2012 , chertow et al . reported the evaluation of cinacalcet therapy to lower cardiovascular events ( evolve ) trial in 3883 patients receiving long - term hemodialysis treatment .
it was the first trial specifically designed to evaluate cinacalcet treatment plus standard of care versus placebo plus standard of care on patient - centered outcomes , using a primary composite outcome of all - cause mortality or first nonfatal cardiovascular event ( myocardial infarction , myocardial ischemia , heart failure , or peripheral vascular event ) .
secondary end points were cardiovascular mortality , stroke , clinical bone fracture , parathyroidectomy , and components of composite primary end point .
the trial was event driven , requiring 1882 primary end point events for study termination .
its duration had to be extended by 16 months beyond the initially planned 4 years because of lower event rates than anticipated .
the primary analysis was performed on the basis of the intention - to - treat ( itt ) principle .
prespecified secondary analyses included multivariable analyses adjusting for baseline characteristics , and companion analyses with lag censoring , in which data were censored 6 months after patients stopped using a study drug .
the median duration of study drug exposure was 21.2 months in the cinacalcet group versus 17.5 months in the placebo group .
there was a high number of study drug discontinuation by non - protocol - specified reasons in the placebo group , much higher than anticipated , with 20% of patients in that group receiving commercial cinacalcet before the occurrence of a primary event .
this high drop - in rate and other factors limited the statistical power of the trial such that , in contrast to the original assumption of a 20% treatment effect , with the observed study duration and observed rates of events , drop - outs , and drop - ins the re - estimated statistical power was only 54% .
the primary composite end point in the evolve trial was reached in 938 of 1948 patients ( 48.2% ) in the cinacalcet group and in 952 of 1935 patients ( 49.2% ) in the placebo group , stratified according to country and diabetes status ( relative hazard in the cinacalcet group vs. the placebo group , 0.93 ; 95% confidence interval , 0.851.02 , p=0.11 ) .
thus there was a 7% nonsignificant reduction in the risk of the primary composite end point with cinacalcet in the itt analysis .
after adjustment for baseline characteristics , there was a nominally significant 12% reduction in risk .
although analyses accounting for study drug exposure are subject to chance , bias , and confounding , there were consistent ( and nominally significant ) effects , up to a 15% reduction in the primary composite end point and a 17% reduction in mortality , using the abovementioned prespecified secondary analyses .
as to side effects , hypocalcemia and gastrointestinal adverse events were significantly more frequent in patients receiving cinacalcet , as already reported in the first large cinacalcet trial in 2004 .
thus evolve did not meet its primary end point in the unadjusted itt analysis , although it showed a 7% reduction in the risk of death or cardiovascular events with cinacalcet in hemodialysis patients treated for secondary hyperparathyroidism .
itt analyses adjusted for baseline characteristics suggest that treating secondary hyperparathyroidism with cinacalcet results in nominally significant reductions in the risk of death or cardiovascular events .
numerous experimental studies done in vitro and in vivo have shown that calcimimetics are able to inhibit the mineralization of vsmc and the progression of vascular calcification , respectively .
however , in the clinical arena the superiority of calcimimetics over standard of care concerning the progression of vascular calcification and hard cardiovascular outcomes in patients with ckd stage 5d , although probable , has not yet been proven definitively .
the limited statistical power of both the advance trial and the evolve trial done in patients who are frequently frail and chronically ill is certainly the main reason for the persisting uncertainty . | ### Summary:
: in the past decade , several experimental studies demonstrated an inhibitory effect of calcimimetics on the progression of vascular calcification in animals with chronic kidney disease ( ckd ) , in keeping with the expression of the calcium - sensing receptor ( car ) in vascular tissue .
in addition , calcimimetics were also found to prevent the arterial remodeling caused by ckd and to slow the progression of atherosclerosis in uremic rats and mice , respectively .
the mode of action of these car modulators could be both via a better control of secondary hyperparathyroidism and direct effects on the vessel wall .
two main clinical trials , advance and evolve , recently evaluated in patients with ckd stage 5d the effects of the calcimimetic cinacalcet on the progression of vascular calcification and hard cardiovascular outcomes , respectively .
both trials missed their respective primary end point by intent - to - treat analysis although by other prespecified analyses , including adjustment for baseline characteristics , there was strong suggestive evidence in favor of reductions in risk , in agreement with numerous experimental studies .
further clinical trials are needed to settle this issue definitively . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: risk for pd is primarily related to increased age , and the most vulnerable neurons are the dopaminergic neurons in the substantia nigra .
destruction of these neurons leads to a disruption of the pathway between the substantia nigra and striatum and produces a severe dopamine deficiency .
dopamine plays an important role in the communication between the thalamus , striatum , and cortex .
reduction of dopamine levels leads to the cardinal motoric features of parkinson 's disease : tremor , generalized slowness of movement , and difficulty transitioning from one movement to the next .
the two most pressing therapeutic challenges in pd are to ( 1 ) provide a stable level of dopamine replacement and ( 2 ) slow or halt disease progression as reviewed [ 24 ] .
pharmacological treatment of pd is satisfactory in the early stages of the disease but becomes problematic as the disease progresses .
treatment with the potent dopamine precursor l - dopa is eventually required for almost all patients , and its erratic absorption and short half - life lead to the development of disabling fluctuations in the treatment response . providing a continuous intracerebral source of dopamine by using cell - based therapy
one strategy has been to use hrpe cells as a local source of l - dopa [ 711 ] .
cell transplantation of hrpe using cross - linked gelatin microcarriers has been used in preclinical and clinical studies of pd and appears to be a safe technique [ 8 , 12 , 13 ] . however
, the therapeutic potential for this platform has been questioned due to the recently reported failure of the commercially sponsored phase ii clinical trial . among the several potential contributing factors to the lack of efficacy , we would like to point out three specifically .
firstly , there may have been a failure to achieve long - term survival of the hrpe monolayers on the gelatin - based microcarriers .
immune system responses to the graft may have been responsible for graft failure , and these could be ameliorated by the use of immunosuppression in future trials or avoided by the use of autologously produced hrpe cultured from a small biopsy .
secondly , long - term survival of the graft may also be hindered by digestion of the gelatin - based microcarrier , needed to keep hrpe as a differentiated functional monolayer .
inert plastic materials might provide for a more stable microcarrier since these will not be degraded .
finally , the failure to account for the role of neurotrophic factors in the positive results seen in preclinical and phase 1 trials could be an important aspect . the clinical benefit found in the initial trial and previously described in both rat and nonhuman primate models of pd [ 8 , 14 ]
however , some of the observed benefit could be related to the release of neuroprotective factors such as pigment epithelium - derived factor ( pedf ) [ 16 , 17 ] and vascular endothelial growth factor - a ( vegf - a ) .
indeed , primate studies of hrpe transplantation have indicated a persistent clinical benefit despite little or no long - term survival of the initial engraftment as assessed by both behavioral and neuroimaging measures .
these data suggest that a neurorestorative effect outlasting survival of the cell transplant was induced .
the phase ii trial design lacked screening of the cells for normal levels of production of pedf or vegf - a prior to implantation .
we believe it would be a mistake to allow the result of the single phase ii trial to prematurely halt further development of the hrpe platform . to reinvigorate this field , other properties and new manipulations of hrpe cells need to be put forth .
it is in this regard that we emphasize and further extend the important findings that ( 1 ) pedf and vegf - a are neurotrophic and neuroprotective factors in culture models of pd [ 17 , 19 ] , ( 2 ) the pedf level of hrpe cells is subject to variability depending on the source and also the pigmentation level , and ( 3 ) the pedf level is regulated by l - dopa via the g - protein - coupled receptor gpr143 ( oa1 ) .
further investigations of the neurotrophic potential of hrpe cells , due to secretion of pedf and vegf - a , have the potential to revive interest in the hrpe cell platform as cell transplantation therapy for pd .
however , further understanding of the regulation of these factors in hrpe cells will be required , particularly since l - dopa is central to the strategy of dopamine replacement using hrpe transplantation . a reciprocal regulation of pedf and vegf - a is known in many body tissues [ 16 , 17 , 22 ] ; for example , when vegf - a levels are high , pedf levels are generally low and vice versa .
since activation of gpr143 up - regulates pedf production and secretion , it would be logical to investigate if there is also a reciprocal effect on vegf - a .
further investigation of the neurotrophic potential of hrpe cells should be coupled with research to aid in the development of microcarriers with increased long - term stability .
such studies would allow the development of more stringent criteria that could be used to screen hrpe cell lines and predict their likelihood of robust clinical efficacy .
the experiments described here take a first step in this direction by ( 1 ) examining the levels of pedf and vegf - a secretion of hrpe on different types of plastic - based microcarriers and ( 2 ) investigating if there is an effect of l - dopa on regulation of vegf - a secretion as has been shown for pedf secretion .
rpe cells were isolated from human donor eyes obtained from advanced bioscience resources as described [ 23 , 24 ] and maintained in chee 's essential medium replacement media ( cem - rm ) . to seed the microcarriers , hrpe cells ( 1 10 )
were plated in a 12.5 cm flask coated with 3% agar and gently rocked for 2 hours with 100 l microcarriers delivered as a 1 : 1 ratio ( v / v ) microcarrier to media slurry , 200 l total volume .
the total number of microcarriers differed among the microcarrier types as the microcarrier size differed , but the packed volume of microcarriers was the same in each group .
we used four types : the gelatin - based cultispher microcarriers ( macroporous gelatin microcarriers , diameter : 130380 m ; percell biolytica , astorp , sweden ) , as well as 3 plastic - based microcarriers from solohill engineering ( ann arbor mi ) that are free from animal products and fda approved : hillex ii ( modified polystyrene with cationic trimethyl ammonium , diameter : 160180 m ) , plastic plus ( cross - linked polystyrene , cationic charged , diameter : 90150 m ) , and pronectin f ( trademark solohill , polystyrene coated with recombinant rgd containing protein , diameter 90150 m ) microcarriers . to determine whether gpr143 signaling activity controlled vegf - a secretion , we used a strategy similar to that which illustrated the receptors control over pedf .
hrpe cells were plated into 24-well plates in cem and maintained at confluency for 3 - 4 months to facilitate differentiation of the monolayers .
because l - dopa is the endogenous ligand for gpr143 , and all pigmented cells produce l - dopa , we used 200 m phenyl thiourea ( ptu ) to inhibit the endogenous production of l - dopa by tyrosinase , which then downregulates the gpr143 signaling pathway , allowing us to control the signaling pathway and use a defined l - dopa concentration . in the presence of ptu
, we then added 1.0 m l - dopa to stimulate the gpr143 signaling pathway .
each treatment was on the cells for 72 hours , after which the media was collected and immediately frozen at 80c .
images were acquired digitally on an olympus ix70 inverted microscope and camera using olympus magnafire software using a 20x objective ( 400x magnification ) .
enzyme - linked immunosorbent assays ( elisas ) were used to determine the concentrations of vegf - a ( r&d systems , minneapolis , mn , usa ) , pedf ( chemicon international , temecula , ca , usa ) , glial - cell - line - derived neurotrophic factor ( gdnf ; promega , madison , wi , usa ) and brain - derived neurotrophic factor ( bdnf ; promega , madison , wi , usa ) in conditioned medium from hrpe cells grown on microcarriers or normal tissue culture flasks . the medium was harvested from the hrpe cultures every 3 - 4 days to produce the conditioned medium ( cm ) samples over long - term time courses .
elisa results were obtained using an emax microtiter plate reader ( molecular devices , downingtown pa , usa ) .
the hrpe cells were seeded onto the microcarriers and followed for 2 months in culture .
figure 1 shows example photomicrographs of the different plastic - based microcarriers covered with monolayers of hrpe at 1 and 2 months after seeding .
figures 1a and 1b depict hrpe cells on hillex ii microcarriers , at 1 month and 2 months .
the hrpe formed a clearly visible monolayer around the microcarrier with the characteristic melanin pigment and the polygonal morphology reminiscent of the normal histological features found in vivo .
figures 1c and 1d depict hrpe cells on plastic plus microcarriers , and figures 1e and 1f depict hrpe cells on pronectin f microcarriers . from the visual inspection ,
the hillex ii microcarriers appear to have the most uniform monolayer , but all microcarriers had significant clumping .
the hrpe cells on the plastic plus microcarriers generally appeared as an amorphous mass of cells and microcarriers as illustrated .
the hrpe cells on the pronectin f microcarriers were generally present as a monolayer but not as regular as on the hillex ii microcarriers .
the pedf present in hrpe media was measured in a series of elisas . in all , the elisa results show a significant pedf secretion into the medium by hrpe cells over 2 months .
for each of the four types of microcarrier with monolayers of hrpe cells , the pedf concentration was measured for samples collected every few days for 2 months , as shown in figure 2 .
this was explained by the inability of the cultispher to create a sufficient base for hrpe cells to form a healthy monolayer .
the other three microcarrier types , hillex ii , plastic plus , and pronectin f all cultured with hrpe from the same donor eye , provided comparable pedf levels . after a short rising phase , maximal expression levels were reached at about 3 - 4 ng / ml from the hillex ii microcarriers and about 2 ng / ml from plastic plus and pronectin f microcarriers , and the pedf concentration remained stable for the duration of the experiment ( 2 months ) as shown in figure 2 .
the vegf - a present in hrpe media was measured in a series of elisas . in all , the elisa results show a significant vegf - a secretion into the medium by hrpe cells over time . for each of the four types of microcarrier with monolayers of hrpe cells , the vegf - a concentration was measured for samples collected every few days for 2 months , as shown in figure 3 .
the cells on the cultispher microcarrier secreted insignificant amounts of vegf - a , which again was attributed to largely unsuccessful growth of cultures of hrpe cells on cultispher over time .
the other three microcarrier types hillex ii , plastic plus , and pronectin f , provided comparable vegf - a levels .
after a rising phase of about 20 days , stable expression levels were reached at about 15 ng / ml , and the vegf - a concentration remained stable for the duration of the experiment ( 2 months ) as shown in figure 3 . the higher variability within the pedf versus the vegf - a time course is explained by the fact that the pedf concentration measured is much closer to the detection threshold than the vegf - a concentration .
the gdnf present in hrpe media was measured in a series of elisas . in all , the elisa results showed a significant gdnf secretion into the medium by hrpe cells grown on hillex ii , plastic plus , and pronectin f microcarriers only over the first 3 weeks as depicted in figure 4 .
after day 22 the gdnf level had dropped below the detection threshold . even at the start
, the gdnf concentration was only in the pg / ml range , compared to vegf - a and pedf for which ng / ml concentrations were measured .
we also examined if bdnf was present in hrpe media as measured in a series of elisas . in all
, the elisa results showed that the hrpe cells did not secrete any measurable bdnf into the medium on all microcarriers tested at any time point ( data not shown ) .
we have previously shown that gpr143 signaling regulates pedf production in hrpe cells . to extend this finding , we investigated regulation of vegf - a output in hrpe cells , using the tissue - type , stable , pigmented monolayer for a minimum of 3 months prior to experiment initiation .
the tyrosinase inhibitor ptu was used to block endogenous l - dopa production and allow control of oa1 signaling without complicated endogenous activity .
we added 200 m ptu + 1 m l - dopa which caused a significant decrease in vegf - a production that was restored to baseline when l - dopa was removed .
this decrease of vegf - a production after addition of l - dopa compared to the untreated cells ( p < 0.0005 , paired t - test with bonferroni correction , n = 9 ) is shown in figure 5 .
after the l - dopa was removed , there was a significant increase of vegf - a production ( p < 0.0005 , paired t - test with bonferroni correction , n = 9 ) by the cells , returning toward baseline .
the comparison of the cells at baseline and after the washout period ( paired t - test with bonferroni 's correction , n = 9 ) shows no significant change in vegf - a concentration .
rpe cells have been studied as a transplantation platform for the treatment of pd based on their ability to produce l - dopa as intermediate in the melanin synthesis pathway and thus provide a source of continuous intracerebral dopamine replacement . in their normal anatomical location ,
rpe cells function to facilitate retinal survival and activity , in part by the secretion of the neurotrophic factors pedf and vegf - a [ 17 , 25 , 26 ] .
these factors could potentially provide an additional benefit in pd by virtue of neuroprotective effects on dopaminergic neurons .
both of these molecules have been extensively studied with regard to their role in controlling tissue vascularity , where they have opposing effects to either , respectively , inhibit or promote angiogenesis [ 16 , 17 , 26 ] .
in addition to their role in controlling angiogenesis , recent studies have supported an important neurotrophic function for both molecules in the cns where they may work in concert .
neuroprotective action of pedf has also been described in a variety of neuronal cell types grown in vitro as well as in a postnatal organotypic culture model of motor neuron degeneration [ 27 , 28 ] .
pedf prevented the death and atrophy of spinal motor neurons in vivo in the developing neonatal mouse after axotomy .
of importance for the current study , pedf has been shown to be both neurotrophic and neuroprotective in two in vitro models of pd .
it has been shown that vegf - a has neurotrophic and neuroprotective properties in explants of the ventral mesencephalon .
vegf - a has been shown to cause axonal outgrowth on cultured ganglia in a dose - responsive manner . at vegf - a concentrations ( 1050 ng / ml ) comparable to the level found in hrpe - conditioned media in this study , neuroprotective effects
unfortunately , at higher concentrations , because of its angiogenic nature , vegf - a may cause increased permeability of the blood - brain barrier , which could be detrimental in causing cerebral edema or other untoward effects .
if hrpe cells are to be implanted in the brains of pd patients as a therapy , it will be important to establish that vegf - a production is sufficient for neuroprotection but below the threshold for disruption of the blood - brain barrier .
the combined neurotrophic effects and the exact ratio of pedf and vegf - a could also be important considerations . a possible concerted neurotrophic effect by pedf and vegf - a in pd was suggested by yasuda et al .
reporting a significantly positive correlation in the striatal levels of pedf and vegf - a in brains acquired at autopsy in pd patients .
this study also monitored the striatal levels of pedf relative to the vegf - a levels in a rodent model following a toxic insult to the dopaminergic pathway .
acute damage to dopaminergic neurons induced a rise in pedf levels in the cns , supporting the hypotheses that pedf acts as an endogenous natural neuroprotective response factor . in this study we found that hrpe cells grown on plastic - based microcarriers retain their ability to produce both pedf and vegf - a , but we were unable to produce long - term cultures of hrpe cells on gelatin - based cultispher microcarriers .
thus , by virtue of the cells failing after initial attachment , we did not observe significant levels of either neurotrophic factor with those microcarriers .
the hrpe cells transplanted in the spheramine clinical trials utilized gelatin - based spheramine microcarriers , and their potential to produce pedf and vegf - a was never investigated . the extent to which neuroprotection is operative in clinical trials of hrpe transplantation remains speculative , but is in our opinion deserving of due consideration .
additional reasons must also be considered to explain the failure of the phase ii clinical trial to show efficacy despite promising preclinical [ 810 , 14 ] and phase i clinical trials .
subsequent pathology data showed that most cells did not survive implantation for more than 6 months , raising doubts about the long - term stability of the graft .
since one of the potential pitfalls of the clinical trial is that the gelatin - based spheramine microcarriers might have been digested over time , we investigated nondegradable microcarriers in their potential to provide healthy hrpe growth , survival , and neurotrophic output [ 20 , 36 ] .
cultispher microcarriers were ineffective in achieving healthy hrpe monolayers as evidenced by the lack of pigmented cells covering the microcarriers .
thus , it was not surprising that little pedf or vegf - a was produced using that substrate .
plastic plus , pronectin f , and hillex ii microcarriers on the other hand all have potential as microcarriers for hrpe growth and potential implantation .
the hrpe cells appeared the most differentiated , pigmented , and regular in height and thickness on the hillex ii microcarriers .
interestingly , both the pedf ( 24 ng / ml ) and the vegf - a ( 15 ng / ml ) outputs of the hrpe cells on all three plastic - based microcarriers were very similar throughout the two - month time course , even though the appearance of the cultures was significantly different .
we did not investigate the neurotrophic effect of the hrpe cells grown on microcarriers in this study , but based on our prior study evaluating the neurotrophic potential of conditioned media ( rpe - cm ) from 2-month - old fully differentiated hrpe cultures before and after pedf depletion , we can conclude that over 50% of the neurotrophic effect on cultured neurons that was produced by hrpe cells is due to pedf production .
we can speculate that the remainder of that effect can be mostly attributed to vegf - a , since we showed in the current study that vegf - a is secreted throughout the study at significant levels whereas the hrpe cells do not produce measurable amount of bdnf at any time point ( data not shown ) , and the gdnf level ( figure 4 ) drops below detection threshold by the 3rd week of culture . in a parallel experiment , we investigated the regulation of the neurotrophic output in hrpe cells by l - dopa .
an interesting facet of the regulation of pedf secretion is the linkage to an autocrine loop that regulates tyrosinase activity and pigment synthesis utilizing l - dopa and gpr143 .
gpr143 is a g - protein - coupled receptor with highest expression levels found in rpe cells .
gpr143 signaling is critical for full expression of the l - dopa synthetic enzyme tyrosinase .
l - dopa is not only a precursor for the formation of melanin , but also acts to increase melanogenesis by activating the gpr143 receptor creating a positive feedback loop .
genetic defects in gpr143 cause ocular albinism , a disorder of pigmentation that leads to vision loss due to changes in retinal neuron development and survival .
the exact cause of the secondary neuronal loss observed in this disorder has been debated , but may reflect the decremental changes in pedf production and subsequent loss of retinal neurotrophism
. a better understanding of the influence of l - dopa on the neurotrophic output of rpe cells is also required for the potential use of rpe cell transplantation in pd .
since there is a reciprocal yin and yang like effect of pedf and vegf - a regulation , at work in many cell types , including the eye , we sought to test whether gpr143 signaling , which upregulates pedf secretion from hrpe cells , may downregulate vegf - a secretion . to test this
we used the same experimental method used previously to illustrate upregulation of pedf by gpr143 signaling .
vegf - a secretion was reduced significantly by induction of gpr143 signaling using the ptu / l - dopa paradigm .
thus , we suggest that in hrpe cells , gpr143 up - regulates pedf while simultaneously downregulating vegf - a .
in addition to the advance in the field of rpe cell transplantation , this observation has significant implications for our understanding of pigmentation - related eye diseases such as albinism and age - related macular degeneration .
overall , it is apparent that hrpe cells grown on plastic - based microcarriers produce levels of both pedf and vegf - a that are in a range that would support a neuroprotective effect . the levels of pedf ( maximum around 4 ng / ml ) were higher than the 1 ng / ml pedf that was reported to be neuroprotective in both 6-ohda and rotenone rat midbrain culture models . in this paper
we show that the secretion of vegf - a is downregulated by l - dopa .
this effect was partial ( less than 15% ) and did not eliminate vegf - a secretion under any conditions tested .
the levels of vegf - a ( maximum around 15 ng / ml ) are sufficient to expect a neuroprotective effect , since 1 ng / ml vegf - a has been shown to provide a maximal protection in a 6-ohda model of pd .
the vegf - a levels also appear to be low enough that the negative effect of increased vessel formation may not be an issue . in rodent models ,
pathological vasculogenesis was observed after implantation of bhk cells expressing vegf - a at approximately 40 ng / ml . it is important to note that future manipulation of the gpr143 pathway could be used to optimize and balance the neurotrophic production of hrpe cells .
in future work the plastic - based hrpe microcarriers should be tested in vivo employing rodent models of neurodegeneration , to evaluate the long - term survival of the hrpe and the continued ability to release therapeutically relevant amounts of pedf and vegf - a after transplantation into the brain .
the relative contribution of pedf versus vegf - a to the expected neurotrophic effects should also be further investigated in vivo .
human rpe cells can be successfully grown and differentiated on 3 different types of fda - approved plastic - based microcarriers over an extended period of time .
the hrpe microcarriers produce significant amounts of two growth factors with neuroprotective potential , pedf and vegf - a .
the regulation of both factors can be reciprocally regulated by modulation of the gpr143/oa1 pathway . | ### Summary:
: human retinal pigment epithelial ( hrpe ) cells have been tested as a cell - based therapy for parkinson 's disease but will require additional study before further clinical trials can be planned .
we now show that the long - term survival and neurotrophic potential of hrpe cells can be enhanced by the use of fda - approved plastic - based microcarriers compared to a gelatin - based microcarrier as used in failed clinical trials .
the hrpe cells grown on these plastic - based microcarriers display several important characteristics of hrpe found in vivo : ( 1 ) characteristic morphological features , ( 2 ) accumulation of melanin pigment , and ( 3 ) high levels of production of the neurotrophic factors pigment epithelium - derived factor ( pedf ) and vascular endothelial growth factor - a ( vegf - a ) . growth of hrpe cells on plastic - based microcarriers led to sustained levels ( > 1 ng / ml ) of pedf and vegf - a in conditioned media for two months .
we also show that the expression of vegf - a and pedf is reciprocally regulated by activation of the gpr143 pathway .
gpr143 is activated by l - dopa ( 1 m ) which decreased vegf - a secretion as opposed to the previously reported increase in pedf secretion .
the hrpe microcarriers are therefore novel candidate delivery systems for achieving long - term delivery of the neuroprotective factors pedf and vegf - a , which could have a value in neurodegenerative conditions such as parkinson 's disease . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the 363 individuals who entered the study were selected from a population survey carried out in 19901991 in the health district of cremona ( lombardy , italy ) that was performed to determine the prevalence of diabetes in italy according to an oral glucose tolerance test ( ogtt ) and world health organization criteria ( 13 ) .
fasting plasma leptin , -tumor necrosis factor receptor 2 ( -tnf - r2 ) , and mcp-1/ccl2 concentrations were measured in patients with type 2 diabetes ( known to be affected or previously undiagnosed ) ( n = 99 ) and patients with impaired glucose tolerance ( igt ) ( n = 77 ) for whom an aliquot of frozen plasma sample was available , which was stored at 80c and had not been previously thawed . from the above - described population , 187 individuals with normal glucose tolerance ( ngt )
were randomly selected to be comparable to the group of patients with type 2 diabetes and igt in terms of age and anthropometric parameters .
past medical history and clinical data of subjects were collected through a standard protocol conducted by trained interviewers .
a venous blood sample was collected after a 12-h overnight fast ; thereafter , a 75-g oral glucose monohydrate was given , and a further venipuncture was performed 2 h later .
anthropometric measures were obtained by the same trained individual using the same instruments for all subjects .
heart rate and systolic and diastolic blood pressures were taken twice , at the beginning and at the end of the visit , in the sitting position and after at least a 10-min rest using a full automatic noninvasive sphygmomanometer .
fifteen years later , vital status and time of death were ascertained through regional health registry files and causes of death were classified using the icd-8 and icd-9 codes 401448 ( cvd ) , 410414 ( coronary heart disease ) , and 430438 ( stroke ) .
the protocol was approved by the ethics committee of the istituto scientifico h san raffaele .
diabetes was defined at that time according to previously known diabetes status ( patients taking oral hypoglycemic agents ) or according to the results of the ogtt and on the basis of world health organization criteria ( basal plasma glucose > 7.8 or > 11.1 mmol / l after a 2-h oral glucose load ) . patients with known diabetes
igt was defined as basal plasma glucose < 7.8 mmol / l and plasma glucose > 7.8 but < 11 mmol / l after a 2-h oral glucose load .
metabolic syndrome was defined according to the definition of the national cholesterol education program adult treatment program iii .
blood was collected into tubes with glycolytic inhibitor , and the glucose concentration was measured within 34 h in the central laboratory through the god - pap glucose oxidase method ( boehringer mannheim , milan , italy ) with a hitachi 705 autoanalyzer . at the same time fibrinogen , aspartate aminotransferase ( ast ) , alanine aminotransferase ( alt ) , -glutamyl transferase ( ggt ) , and alkaline phosphatase ( alp ) were also determined .
an additional 20 ml of fasting blood was immediately centrifuged , and plasma was obtained for the assessment in the central laboratory of insulin , triglycerides , and total and hdl cholesterol .
the plasma human mcp-1/ccl2 concentration was measured in 2001 using a noncommercial sandwich enzyme - linked immunosorbent assay as described previously ( 15 ) ; the enzyme - linked immunosorbent assay for mcp-1/ccl2 is specific for human mcp-1 and did not detect the closely related human chemokines mcp-2 and mcp-3 ( 16 ) .
leptin concentration was determined as described previously ( 13 ) by a radioimmunoassay with a human kit ( linco research , st .
intra - assay and interassay coefficients of variation ( cvs ) were 1.5 and 1.9% , respectively .
insulin was determined by a radioimmunoassay kit ( intra - assay and interassay cvs were 6.0 and 5.3% , respectively ) ( technogenetics , medgenics , brussels , belgium ) .
-tnf - r2 was measured with an enzyme immunoassay following the manufacturer 's ( immunotech beckman coulter , marseille , france ) recommendations as described previously ( 13 ) .
total cholesterol and triglycerides were measured by enzymatic methods ( boehringer mannheim , mannheim , germany ) with the ciba corning 550 express autoanalyzer .
the hdl fraction was separated from plasma by precipitation with polyethylene glycol using a colortest kit ( roche , basel , switzerland ) . in 2004 ,
c - reactive protein ( crp ) levels ( n high - sensitivity crp assay ; dade - behring , marburg , germany ) were measured in a subgroup of older individuals ( 65 years old ; n = 447 ) within the entire population of the cremona study and were reported in another article ( 17 ) .
with respect to that assessment , we have data for 113 subjects in whom mcp-1/ccl2 and high - sensitivity crp ( hs - crp ) were simultaneously available .
bmi was calculated as weight in kilograms divided by the square of height in meters .
insulin sensitivity was estimated using the quantitative insulin sensitivity check index ( quicki ) obtained from fasting baseline determinations ( 18 ) and calculated as the logarithm and the reciprocal of the insulin - glucose product :
alcohol consumption was calculated as units of alcohol ( glass of wine = 20 units , glass of aperitif = 30 units , and glass of liquor = 80 units ) .
anova and analysis were used for comparison between groups , and the bonferroni adjustment was used for post hoc comparisons . because of the skewed distribution of serum leptin , insulin , triglycerides , fibrinogen , glucose , ast , alt , ggt , and alp , log - transformed values were used in the analysis .
the association of the risk factors with cvd mortality after the 15-year observational period was estimated by the cox univariate proportional hazards model .
a multivariate cox proportional model ( stepwise ) , including parameters with p < 0.1 on univariate analysis , was used to investigate the independent association of the risk factors with cvd mortality .
diabetes was defined at that time according to previously known diabetes status ( patients taking oral hypoglycemic agents ) or according to the results of the ogtt and on the basis of world health organization criteria ( basal plasma glucose > 7.8 or > 11.1 mmol / l after a 2-h oral glucose load ) . patients with known diabetes did not undergo the ogtt .
igt was defined as basal plasma glucose < 7.8 mmol / l and plasma glucose > 7.8 but < 11 mmol / l after a 2-h oral glucose load .
metabolic syndrome was defined according to the definition of the national cholesterol education program adult treatment program iii .
blood was collected into tubes with glycolytic inhibitor , and the glucose concentration was measured within 34 h in the central laboratory through the god - pap glucose oxidase method ( boehringer mannheim , milan , italy ) with a hitachi 705 autoanalyzer . at the same time
fibrinogen , aspartate aminotransferase ( ast ) , alanine aminotransferase ( alt ) , -glutamyl transferase ( ggt ) , and alkaline phosphatase ( alp ) were also determined .
an additional 20 ml of fasting blood was immediately centrifuged , and plasma was obtained for the assessment in the central laboratory of insulin , triglycerides , and total and hdl cholesterol .
the plasma human mcp-1/ccl2 concentration was measured in 2001 using a noncommercial sandwich enzyme - linked immunosorbent assay as described previously ( 15 ) ; the enzyme - linked immunosorbent assay for mcp-1/ccl2 is specific for human mcp-1 and did not detect the closely related human chemokines mcp-2 and mcp-3 ( 16 ) .
leptin concentration was determined as described previously ( 13 ) by a radioimmunoassay with a human kit ( linco research , st .
intra - assay and interassay coefficients of variation ( cvs ) were 1.5 and 1.9% , respectively .
insulin was determined by a radioimmunoassay kit ( intra - assay and interassay cvs were 6.0 and 5.3% , respectively ) ( technogenetics , medgenics , brussels , belgium ) .
-tnf - r2 was measured with an enzyme immunoassay following the manufacturer 's ( immunotech beckman coulter , marseille , france ) recommendations as described previously ( 13 ) .
total cholesterol and triglycerides were measured by enzymatic methods ( boehringer mannheim , mannheim , germany ) with the ciba corning 550 express autoanalyzer .
the hdl fraction was separated from plasma by precipitation with polyethylene glycol using a colortest kit ( roche , basel , switzerland ) .
in 2004 , c - reactive protein ( crp ) levels ( n high - sensitivity crp assay ; dade - behring , marburg , germany ) were measured in a subgroup of older individuals ( 65 years old ; n = 447 ) within the entire population of the cremona study and were reported in another article ( 17 ) .
with respect to that assessment , we have data for 113 subjects in whom mcp-1/ccl2 and high - sensitivity crp ( hs - crp ) were simultaneously available .
bmi was calculated as weight in kilograms divided by the square of height in meters .
insulin sensitivity was estimated using the quantitative insulin sensitivity check index ( quicki ) obtained from fasting baseline determinations ( 18 ) and calculated as the logarithm and the reciprocal of the insulin - glucose product :
alcohol consumption was calculated as units of alcohol ( glass of wine = 20 units , glass of aperitif = 30 units , and glass of liquor = 80 units ) .
anova and analysis were used for comparison between groups , and the bonferroni adjustment was used for post hoc comparisons . because of the skewed distribution of serum leptin , insulin , triglycerides , fibrinogen , glucose , ast , alt , ggt , and alp , log - transformed values were used in the analysis .
the association of the risk factors with cvd mortality after the 15-year observational period was estimated by the cox univariate proportional hazards model .
a multivariate cox proportional model ( stepwise ) , including parameters with p < 0.1 on univariate analysis , was used to investigate the independent association of the risk factors with cvd mortality .
subjects with type 2 diabetes and igt were slightly older , but post hoc testing did not reach statistical difference among groups ( table 1 ) .
waist - to - thigh ratio was significantly increased in individuals with type 2 diabetes with respect to that in individuals with ngt ; this feature was more evident in women ( p = 0.0001 ) than in men ( p = 0.274 ) .
systolic ( p = 0.008 ) and diastolic ( p = 0.087 ) blood pressures were higher in women with type 2 diabetes with respect to those in women with ngt , whereas this feature was less evident in men ( p = 0.172 and p = 0.130 for systolic and diastolic pressure , respectively ) .
as expected , fasting and 2-h serum glucose concentrations were increased in patients with type 2 diabetes and igt in comparison with those in subjects with ngt .
total cholesterol and ldl cholesterol were not different in the groups . however , hdl cholesterol and triglycerides differed significantly in patients with type 2 diabetes , which showed unfavorable alterations of the lipid profile .
the lipid profiles of subjects with igt , on the contrary , were not different from those of individuals with ngt .
serum alt , ast , ggt , alp , and fibrinogen were not different in any groups .
patients with type 2 diabetes and igt were characterized by fasting hyperinsulinemia and by insulin resistance expressed as a significantly lower quicki value .
serum leptin were not different in the study groups when leptin concentration was normalized to the bmi units .
anthropometric and laboratory parameters of study subjects data are means sd or n ( % ) .
leptin , insulin , triglycerides , glucose , ast , alt , ggt , and alp are expressed as geometric means sd .
the plasma mcp-1/ccl2 concentration was increased in type 2 diabetic women but not in those with igt with respect to those with ngt ( table 1 ) .
mcp-1/ccl2 was not associated with any anthropometric parameters but showed a significant association with biochemical markers of atherosclerotic disease .
in fact , mcp-1/ccl2 was associated with fasting ( r = 0.15 ; p = 0.007 ) and 2-h plasma glucose after the glucose challenge ( r = 0.14 ; p = 0.04 ) , hdl cholesterol ( r = 0.21 ; p = 0.0003 ) , and plasma triglycerides ( r = 0.15 ; p = 0.01 ) .
these parameters are typical markers of the insulin resistance syndrome ; confirming this observation , quicki was also found to be significantly associated ( r = 0.19 ; p = 0.009 ) .
in addition , mcp-1/ccl2 showed a significant association with -tnf - r2 ( r = 0.14 ; p = 0.01 ) but no association with leptin .
even if mcp-1/ccl2 was not significantly associated with bmi , we tested whether the above - described association of mcp-1/ccl2 was independent of bmi .
the results of this analysis demonstrated that all the correlations remained significant regardless of the parameter of body adiposity .
after 15 years , among the 363 subjects , 82 deaths occurred due to cvd ( 22.6% ) ( table 2 ) .
the cvd mortality rate was 30% in patients with type 2 diabetes ( 30 of 99 ) , 19.5% in individuals with igt ( 15 of 77 ) , and 19.8% in individuals with ngt ( 37 of 187 ) .
in univariate analysis , age ( hr 1.127 [ 95% ci 1.0981.157 ] ; p < 0.0001 ) was associated with cvd mortality , and female sex was less prone to be associated ( 0.429 [ 0.2750.671 ] ; p < 0.0002 ) .
age- and sex - adjusted univariate analysis showed that fasting plasma glucose concentration , mcp-1/ccl2 , fibrinogen , cigarette smoking , and diabetes were significantly associated with cvd mortality ( table 2 ) .
in addition , fasting insulin showed a trend to be associated with cvd mortality ( p = 0.064 ) . when the analysis was performed separately by sex , age , fasting plasma glucose , and mcp-1/ccl2
were significantly associated in both men and women , whereas fasting plasma insulin and smoking were significantly associated with cvd mortality only in men and serum fibrinogen was significantly associated with cvd mortality only in women .
age- and sex - adjusted risk ratio associated with 15 years cardiovascular mortality by univariate analysis data are hr ( 95% ci ) .
multivariate analysis was performed using only variables significant at p < 0.1 in univariate analysis .
the analysis in the entire population ( table 3 ) showed that age , sex , fasting glucose , mcp-1/ccl2 , and smoking were independent predictive variables of cvd mortality ( table 3 ) .
cox proportional hazards model of the predictors of 15 years cvd mortality by multivariate analysis data are hr ( 95% ci ) . only variables significant at p < 0.1 at univariate analysis were tested in the models .
for hs - crp , data on mcp-1/ccl2 and hs - crp were simultaneously available for only 113 subjects .
these subjects were older ( 71 4 years ) than those reported in the present article , and the number of cardiovascular events was 46 .
no correlation between plasma mcp-1/ccl2 and hs - crp ( pearson r = 0.019 ; p = 0.85 ) was detected . in univariate analysis hs - crp
was not related to cvd ( hr 1.029 [ 95% ci 0.9841.076 ] ; p = 0.22 ) , and in this smaller cohort mcp-1/ccl2 but not hs - crp ( 1.030 [ 0.9861.077 ] ; p = 0.19 ) showed a trend to be significantly associated with cvd mortality in age- and sex - adjusted multivariate analysis ( 1.001 [ 1.0001.002 ] ; p = 0.0593 ) .
subjects with type 2 diabetes and igt were slightly older , but post hoc testing did not reach statistical difference among groups ( table 1 ) .
waist - to - thigh ratio was significantly increased in individuals with type 2 diabetes with respect to that in individuals with ngt ; this feature was more evident in women ( p = 0.0001 ) than in men ( p = 0.274 ) .
systolic ( p = 0.008 ) and diastolic ( p = 0.087 ) blood pressures were higher in women with type 2 diabetes with respect to those in women with ngt , whereas this feature was less evident in men ( p = 0.172 and p = 0.130 for systolic and diastolic pressure , respectively ) .
as expected , fasting and 2-h serum glucose concentrations were increased in patients with type 2 diabetes and igt in comparison with those in subjects with ngt .
total cholesterol and ldl cholesterol were not different in the groups . however , hdl cholesterol and triglycerides differed significantly in patients with type 2 diabetes , which showed unfavorable alterations of the lipid profile .
the lipid profiles of subjects with igt , on the contrary , were not different from those of individuals with ngt .
serum alt , ast , ggt , alp , and fibrinogen were not different in any groups .
patients with type 2 diabetes and igt were characterized by fasting hyperinsulinemia and by insulin resistance expressed as a significantly lower quicki value .
serum leptin were not different in the study groups when leptin concentration was normalized to the bmi units .
anthropometric and laboratory parameters of study subjects data are means sd or n ( % ) .
leptin , insulin , triglycerides , glucose , ast , alt , ggt , and alp are expressed as geometric means sd .
the plasma mcp-1/ccl2 concentration was increased in type 2 diabetic women but not in those with igt with respect to those with ngt ( table 1 ) .
mcp-1/ccl2 was not associated with any anthropometric parameters but showed a significant association with biochemical markers of atherosclerotic disease .
in fact , mcp-1/ccl2 was associated with fasting ( r = 0.15 ; p = 0.007 ) and 2-h plasma glucose after the glucose challenge ( r = 0.14 ; p = 0.04 ) , hdl cholesterol ( r = 0.21 ; p = 0.0003 ) , and plasma triglycerides ( r = 0.15 ; p = 0.01 ) .
these parameters are typical markers of the insulin resistance syndrome ; confirming this observation , quicki was also found to be significantly associated ( r = 0.19 ; p = 0.009 ) .
in addition , mcp-1/ccl2 showed a significant association with -tnf - r2 ( r = 0.14 ; p = 0.01 ) but no association with leptin .
even if mcp-1/ccl2 was not significantly associated with bmi , we tested whether the above - described association of mcp-1/ccl2 was independent of bmi .
the results of this analysis demonstrated that all the correlations remained significant regardless of the parameter of body adiposity .
after 15 years , among the 363 subjects , 82 deaths occurred due to cvd ( 22.6% ) ( table 2 ) .
the cvd mortality rate was 30% in patients with type 2 diabetes ( 30 of 99 ) , 19.5% in individuals with igt ( 15 of 77 ) , and 19.8% in individuals with ngt ( 37 of 187 ) .
in univariate analysis , age ( hr 1.127 [ 95% ci 1.0981.157 ] ; p < 0.0001 ) was associated with cvd mortality , and female sex was less prone to be associated ( 0.429 [ 0.2750.671 ] ; p < 0.0002 ) .
age- and sex - adjusted univariate analysis showed that fasting plasma glucose concentration , mcp-1/ccl2 , fibrinogen , cigarette smoking , and diabetes were significantly associated with cvd mortality ( table 2 ) . in addition , fasting insulin showed a trend to be associated with cvd mortality ( p = 0.064 ) . when the analysis was performed separately by sex , age , fasting plasma glucose , and mcp-1/ccl2
were significantly associated in both men and women , whereas fasting plasma insulin and smoking were significantly associated with cvd mortality only in men and serum fibrinogen was significantly associated with cvd mortality only in women .
age- and sex - adjusted risk ratio associated with 15 years cardiovascular mortality by univariate analysis data are hr ( 95% ci ) .
multivariate analysis was performed using only variables significant at p < 0.1 in univariate analysis .
the analysis in the entire population ( table 3 ) showed that age , sex , fasting glucose , mcp-1/ccl2 , and smoking were independent predictive variables of cvd mortality ( table 3 ) .
cox proportional hazards model of the predictors of 15 years cvd mortality by multivariate analysis data are hr ( 95% ci ) . only variables significant at p < 0.1 at univariate analysis were tested in the models . only variables that remained significantly associated are shown .
for hs - crp , data on mcp-1/ccl2 and hs - crp were simultaneously available for only 113 subjects .
these subjects were older ( 71 4 years ) than those reported in the present article , and the number of cardiovascular events was 46 .
no correlation between plasma mcp-1/ccl2 and hs - crp ( pearson r = 0.019 ; p = 0.85 ) was detected . in univariate analysis hs - crp
was not related to cvd ( hr 1.029 [ 95% ci 0.9841.076 ] ; p = 0.22 ) , and in this smaller cohort mcp-1/ccl2 but not hs - crp ( 1.030 [ 0.9861.077 ] ; p = 0.19 ) showed a trend to be significantly associated with cvd mortality in age- and sex - adjusted multivariate analysis ( 1.001 [ 1.0001.002 ] ; p = 0.0593 ) .
in the present study , we have shown that in middle - aged overweight / obese individuals , the fasting plasma mcp-1/ccl2 concentration was related to biochemical risk markers of atherosclerosis and that this concentration was higher in individuals with type 2 diabetes and igt with respect to that in nondiabetic patients .
most importantly , when cvd mortality was assessed retrospectively 15 years after the baseline assessment , we report that mcp-1/ccl2 was independently associated with cvd mortality .
our results showed that diabetes may be a determinant of the circulating levels of mcp-1/ccl2 .
in fact , at baseline , mcp-1/ccl2 was associated with biochemical markers of the metabolic syndrome such as serum triglycerides , hdl cholesterol , and surrogate markers of insulin sensitivity ( quicki ) . with respect to insulin resistance , because obese insulin - resistant subjects are in a proinflammatory state with an increase in intranuclear nuclear factor-b binding activity ( 19 ) and because insulin was shown to suppress the mcp-1/ccl2 plasma concentration in vivo ( 20 ) , insulin resistance itself may explain why mcp-1/ccl2 was increased in our patients .
in addition , the higher amount of plasma mcp-1/ccl2 observed in individuals with type 2 diabetes was correlated with both fasting and 2-h plasma glucose after the glucose challenge , suggesting that hyperglycemia may have an independent contribution in explaining the circulating levels of mcp-1/ccl2 .
this finding was not unexpected because in vitro , advanced glycation end - products , a high glucose concentration , glycated albumin , and glycoxidized ldl enhanced mcp-1/ccl2 expression in human endothelial cells ( 21 ) .
more importantly , the results support the hypothesis that mcp-1/ccl2 may be involved directly in the pathogenesis of atherosclerosis in humans because its baseline serum concentration was independently associated with cvd mortality assessed 15 years after the baseline determination of its fasting plasma concentration .
there are many data in the literature that support a role of mcp-1/ccl2 in the pathogenesis of both the initiation and progression of atherosclerosis .
mcp-1/ccl2 was found to be highly expressed within atherosclerotic lesions ( 22 ) , and its role in atherogenesis is consistent with in vitro and in vivo studies in animal models ( 23 ) . in humans , elevated mcp-1/ccl2 serum levels were found to be increased not only in individuals with diabetes but also in subjects at risk because of other risk factors for atherosclerosis , such as age , hypertension , hypercholesterolemia , renal failure , and vascular disease or in individuals with overt coronary artery disease as outlined in the introduction .
recently , a genetic variation in the mcp-1/ccl2 gene was associated with a higher serum concentration of the chemokine and a higher prevalence of myocardial infarction ( 24 ) .
the results of the present study are potentially clinically important . with regard to the inflammatory hypothesis of atherosclerosis
, these data suggest that elevated mcp-1/ccl2 levels , serving as a direct marker of inflammatory activity , may also be a biomarker of the risk of cvd .
holding this view and taking into account the fact that the fasting mcp-1/ccl2 level predicted cvd mortality when assessed 15 years later , we suggest that this chemokine may be an early independent predictor of atherosclerosis and an early biomarker of its natural development in the history of an at - risk individual .
interestingly , within our population the mcp-1/ccl2 plasma concentration was linked more strongly with cvd than the postchallenge plasma glucose concentration , metabolic syndrome , and serum circulating lipids ( table 2 ) .
another clinical implication is that because treatment of several components of the insulin resistance syndrome ( adiposity , dyslipidemia , and hypertension ) had beneficial effects in preventing cardiovascular disease , if subclinical inflammation is indeed another facet of the insulin resistance syndrome , anti - inflammatory treatment may also be beneficial .
a recent randomized clinical trial tested the administration of 20 mg / day rosuvastatin in nondiabetic individuals with anthropometric features similar to those of the subjects in our study ( age , sex , and bmi ) who had ldl cholesterol levels in the normal range but higher circulating hs - crp levels . in this study ,
a 44% reduction of major cardiovascular events along with a significant reduction of hs - crp circulating levels was reported ( 25 ) , suggesting that the effects of this statin may , at least partly , be mediated through anti - inflammatory properties .
in addition , it is known that pharmacological treatment with hydroxymethylglutaryl - coa reductase inhibitors may lower mcp-1/ccl2 levels ( 9 ) .
thus , elevated mcp-1/ccl2 levels could identify patients more likely to benefit from aggressive statin treatment , although we must emphasize that whether treatments to reduce circulating levels of mcp-1/ccl2 are effective in reducing the onset of cvd is yet to be determined . based also on our results ,
the hypothesis that the development of pharmacological tools able to target anti - inflammatory pathways may be a potential approach to reduce rates of vascular events may be true .
the population in which mcp-1/ccl2 plasma concentrations were obtained was small , and larger studies are needed to confirm our results .
conversely , our observational period was 15 years , and we had a high number of events ( 82 cvd deaths in 363 individuals ) relative to the entire population .
an additional limitation was that the distribution of mcp-1/ccl2 plasma concentrations in the individuals with cvd mortality and those without overlapped considerably , suggesting that plasma mcp-1/ccl2 levels alone will not be helpful in predicting cvd mortality .
therefore , we are exploring circulating levels of mcp-1/ccl2 as a systemic surrogate , trying to test whether these may be linked to a local event ( atherosclerosis ) .
however , when mcp-1/ccl2 is considered along with other classic risk factors , it may eventually be useful as a surrogate biomarker in patients with igt and diabetes .
another limitation of the study is that we did not obtain serial plasma mcp-1/ccl2 concentrations .
the association we report in the present work is between one single assessment of the plasma chemokine concentration and the cvd mortality assessed 15 years later , but we have no data about the circulating levels of the chemokine during the observational period . finally , we tested mcp-1/ccl2 along with a standard inflammatory marker such as fibrinogen because that biomarker was measured in 19901991 .
hs - crp is a more reliable marker , but , unfortunately , we only had simultaneous availability of mcp-1/ccl2 and hs - crp for 113 subjects .
even if mcp-1/ccl2 remained associated with cvd mortality in this subset of individuals , suggesting an independent role of mcp-1/ccl2 , a rigorous comparison remains to be done . in summary , in the present study , we report that in middle - aged individuals the plasma mcp-1/ccl2 concentration was related to biochemical risk markers of atherosclerosis and , in particular , to both fasting and post - ogtt plasma glucose concentrations . in the multivariate analysis mcp-1/ccl2
our results showed that diabetes may be a determinant of the circulating levels of mcp-1/ccl2 .
in fact , at baseline , mcp-1/ccl2 was associated with biochemical markers of the metabolic syndrome such as serum triglycerides , hdl cholesterol , and surrogate markers of insulin sensitivity ( quicki ) . with respect to insulin resistance , because obese insulin - resistant subjects are in a proinflammatory state with an increase in intranuclear nuclear factor-b binding activity ( 19 ) and because insulin was shown to suppress the mcp-1/ccl2 plasma concentration in vivo ( 20 ) , insulin resistance itself may explain why mcp-1/ccl2 was increased in our patients .
in addition , the higher amount of plasma mcp-1/ccl2 observed in individuals with type 2 diabetes was correlated with both fasting and 2-h plasma glucose after the glucose challenge , suggesting that hyperglycemia may have an independent contribution in explaining the circulating levels of mcp-1/ccl2 .
this finding was not unexpected because in vitro , advanced glycation end - products , a high glucose concentration , glycated albumin , and glycoxidized ldl enhanced mcp-1/ccl2 expression in human endothelial cells ( 21 ) .
more importantly , the results support the hypothesis that mcp-1/ccl2 may be involved directly in the pathogenesis of atherosclerosis in humans because its baseline serum concentration was independently associated with cvd mortality assessed 15 years after the baseline determination of its fasting plasma concentration .
there are many data in the literature that support a role of mcp-1/ccl2 in the pathogenesis of both the initiation and progression of atherosclerosis .
mcp-1/ccl2 was found to be highly expressed within atherosclerotic lesions ( 22 ) , and its role in atherogenesis is consistent with in vitro and in vivo studies in animal models ( 23 ) . in humans , elevated mcp-1/ccl2 serum levels were found to be increased not only in individuals with diabetes but also in subjects at risk because of other risk factors for atherosclerosis , such as age , hypertension , hypercholesterolemia , renal failure , and vascular disease or in individuals with overt coronary artery disease as outlined in the introduction .
recently , a genetic variation in the mcp-1/ccl2 gene was associated with a higher serum concentration of the chemokine and a higher prevalence of myocardial infarction ( 24 ) .
the results of the present study are potentially clinically important . with regard to the inflammatory hypothesis of atherosclerosis
, these data suggest that elevated mcp-1/ccl2 levels , serving as a direct marker of inflammatory activity , may also be a biomarker of the risk of cvd .
holding this view and taking into account the fact that the fasting mcp-1/ccl2 level predicted cvd mortality when assessed 15 years later , we suggest that this chemokine may be an early independent predictor of atherosclerosis and an early biomarker of its natural development in the history of an at - risk individual .
interestingly , within our population the mcp-1/ccl2 plasma concentration was linked more strongly with cvd than the postchallenge plasma glucose concentration , metabolic syndrome , and serum circulating lipids ( table 2 ) .
another clinical implication is that because treatment of several components of the insulin resistance syndrome ( adiposity , dyslipidemia , and hypertension ) had beneficial effects in preventing cardiovascular disease , if subclinical inflammation is indeed another facet of the insulin resistance syndrome , anti - inflammatory treatment may also be beneficial .
a recent randomized clinical trial tested the administration of 20 mg / day rosuvastatin in nondiabetic individuals with anthropometric features similar to those of the subjects in our study ( age , sex , and bmi ) who had ldl cholesterol levels in the normal range but higher circulating hs - crp levels . in this study ,
a 44% reduction of major cardiovascular events along with a significant reduction of hs - crp circulating levels was reported ( 25 ) , suggesting that the effects of this statin may , at least partly , be mediated through anti - inflammatory properties .
in addition , it is known that pharmacological treatment with hydroxymethylglutaryl - coa reductase inhibitors may lower mcp-1/ccl2 levels ( 9 ) .
thus , elevated mcp-1/ccl2 levels could identify patients more likely to benefit from aggressive statin treatment , although we must emphasize that whether treatments to reduce circulating levels of mcp-1/ccl2 are effective in reducing the onset of cvd is yet to be determined . based also on our results ,
the hypothesis that the development of pharmacological tools able to target anti - inflammatory pathways may be a potential approach to reduce rates of vascular events may be true .
the population in which mcp-1/ccl2 plasma concentrations were obtained was small , and larger studies are needed to confirm our results .
conversely , our observational period was 15 years , and we had a high number of events ( 82 cvd deaths in 363 individuals ) relative to the entire population .
an additional limitation was that the distribution of mcp-1/ccl2 plasma concentrations in the individuals with cvd mortality and those without overlapped considerably , suggesting that plasma mcp-1/ccl2 levels alone will not be helpful in predicting cvd mortality .
therefore , we are exploring circulating levels of mcp-1/ccl2 as a systemic surrogate , trying to test whether these may be linked to a local event ( atherosclerosis )
. however , when mcp-1/ccl2 is considered along with other classic risk factors , it may eventually be useful as a surrogate biomarker in patients with igt and diabetes .
another limitation of the study is that we did not obtain serial plasma mcp-1/ccl2 concentrations .
the association we report in the present work is between one single assessment of the plasma chemokine concentration and the cvd mortality assessed 15 years later , but we have no data about the circulating levels of the chemokine during the observational period . finally , we tested mcp-1/ccl2 along with a standard inflammatory marker such as fibrinogen because that biomarker was measured in 19901991 .
hs - crp is a more reliable marker , but , unfortunately , we only had simultaneous availability of mcp-1/ccl2 and hs - crp for 113 subjects . even if mcp-1/ccl2 remained associated with cvd mortality in this subset of individuals , suggesting an independent role of mcp-1/ccl2 , a rigorous comparison remains to be done . in summary , in the present study , we report that in middle - aged individuals the plasma mcp-1/ccl2 concentration was related to biochemical risk markers of atherosclerosis and , in particular , to both fasting and post - ogtt plasma glucose concentrations . in the multivariate analysis mcp-1/ccl2 | ### Summary:
: objectivemonocyte chemoattractant protein-1 ( mcp-1/ccl2 ) is a chemokine involved into the pathogenesis of atherosclerosis and has prognostic value in the acute and chronic phases in patients with acute coronary syndromes.research design and methodsmcp-1/ccl2 concentration was measured in plasma fractions of 363 middle - aged overweight / obese individuals ( aged 61 12 years , bmi 30.1 6.6 kg / m2 , 15% with type 2 diabetes , and 12% with impaired glucose tolerance ) of a population survey carried out in 19901991 in lombardy , italy ( cremona study ) , and cardiovascular disease ( cvd ) mortality was assessed in 2006 through regional health registry files.resultsat baseline mcp-1/ccl2 was increased in individuals with type 2 diabetes ( p < 0.05 ) and showed significant correlations with biochemical risk markers of atherosclerosis .
after 15 years , among the 363 subjects , there were 82 deaths due to cvd .
in univariate analysis age , sex , fasting glucose and insulin , fibrinogen , glucose tolerance status , smoking habit , and mcp-1/ccl2 were associated with cvd mortality .
age , sex , fasting serum glucose , mcp-1/ccl2 , and smoking habit maintained an independent association with cvd mortality in multiple regression analysis . in a subgroup of 113 subjects in whom
data for c - reactive protein ( crp ) were available , its level was not predictive of cvd mortality.conclusionsin middle - aged overweight / obese individuals mcp-1/ccl2 was independently associated with cvd mortality .
further studies will be necessary to establish its role as a surrogate biomarker and as a potential therapeutic target . |
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: s third law of motion , every action has an equal and opposite reaction . in clinical orthodontics ,
different extraoral and intraoral appliances have been used to preserve anchorage during tooth movement.1 however , while appliances like headgears require patient compliance , intraoral noncompliance appliances cause reciprocal tooth movement at the anchor unit.24 since the successful improvements of implant dentistry in the recent years , different bone anchors have made their use possible as anchorage in orthodontics .
osseointegrated implants need 36 months before loading.12 the somewhat complicated surgical procedure , discomfort during healing and the time needed for osseointegration are their main disadvantages.13 due to the somewhat complex insertion and healing procedures of osseointegrated implants , some researchers investigated the success of the use of screws as temporary anchorage devices .
creekmore and eklund used a vitallium screw below anterior nasal spine for upper incisor intrusion.14 the bone screw remained stable in 1 year period and was removed easily at the end of treatment .
researchers like byloff et al,15 karaman et al,11 gelgor et al4 and kircelli et al16 have shown successful results using intraosseous screws for upper molar distalization .
screws can be used as direct anchorage unit that is connected directly to the teeth to be moved or anchorage teeth can be stabilized with the screw which acts as an indirect anchorage unit .
gelgor et al4 have shown the results of 20 patients that had intraosseous screws used as an indirect anchorage unit to stabilize premolars for upper molar distalization .
they used a titanium intraosseous screw , 1.8 mm in diameter and 14 mm in length as an indirect anchorage unit .
the screw was placed in the anterior paramedian region of the palatal suture , 5 mm posterior to the incisive foramen and 3 mm lateral to the raphe .
upper first premolars were stabilized via a transpalatal arch that was connected to the screw .
distal force was applied to upper first molars using sectional arches and open nickel titanium coil springs between the stabilized premolars and upper first molars . according to the results of their study , the mean molar distalization was 3.9 mm with an average tipping of 8.7 in 3 to 6.2 months . despite their success in molar movement ,
since the screws receive the distalization forces directly , the failure of the screws can not be rare .
this case report aims to demonstrate the treatment result of a dental class ii patient using an intraosseous screw for upper molar distalization .
the distalization appliance presented here was supported by an acrylic nance button to transmit the distalizing forces to the hard palate as well as the screw .
the clinical and radiographic changes of both postdistalization stage and the end of treatment will be presented .
a 19 year old caucasian female who had no history of significant medical problems or any family history of hereditary disease referred to our clinic with a chief complaint of upper midline deviation and palatally displaced upper right lateral incisor .
extraorally , the patient had a balanced facial profile and she had adequate gingival tissue on full smile ( figure 1 ) .
intraorally she had class i canine and molar relationships on left dentition and class ii molar and canine relation on her right dentition .
upper midline deviation was 4 mm to the right and lower midline deviation was 2 mm to the right .
her left upper first molar had endodontic treatment and she also had big restorations on teeth 16 , and 47 .
temporomandibular joint showed no signs of clicks or crepitation , and the facial and masticatory muscles were asymptomatic .
cephalometric evaluation showed that the patient had an sna angle of 80.9 , an snb angle of 79.5 , and an anb angle of 1.4 the mandibular plane ( sn - gome ) angle was 25.5 , the position of lower incisors were 22 , and 4 mm relative to the na plane , and the position of upper incisors were 18 , and 4 mm relative to na plane .
the upper lip was 5.0 mm behind e plane and the lower lip was 3 mm behind e plane .
the nasolabial angle was 110 ( figure 4 ) ( table 1 ) . the pretreatment panoramic radiograph can be seen in figure 5 .
the treatment objectives included achievement of a class i molar and canine relationships with distalization of the upper right molar .
besides , her low sn - gogn angle and increased overbite would complicate any extractions .
therefore the use of an intraoral distalization appliance that was supported by an intraosseous screw was planned .
prior to distalization , upper left third molar was extracted . a titanium intraosseous screw ( imf intermaxillary screw , stryker , leibinger , germany ) which is 2.0 mm in diameter and
the screw was inserted in the anterior paramedian region of the palatal suture , 45 mm posterior to the incisive foramen and 34 mm lateral to the median line .
primary stabilization was assessed with a tweezer intraorally and screw position was checked by occlusal radiographs after insertion .
one week after screw insertion , impressions were obtained and a plaster model was prepared .
occlusal wires extending to the anchor first premolars were bended from 0.8 mm wire and placed to the model .
a self - cure acrylic was placed on to the screw , covering the extensions of the occlusal wires .
the appliance adaptation was checked clinically , and the occlusal wires were bonded to the upper first premolars using light - cure composite resin ( transbond xt , 3 m unitek , monrovia , california ) .
bilateral sectional arches ( 0.0160.022 inch ) and 0.036 inch nickel - titanium open coil springs were inserted between the first premolar and the first molar with a continuous force of approximately 250 g per side ( figure 6 ) .
lateral cephalometric radiograph taken at the end of distalization can be seen in figure 7 . at the end of distalization ,
a nance appliance was fabricated over the same screw using the method described during fabrication of the initial appliance .
total treatment time was 22 months . for retention , an upper hawley retainer and a lower 33 lingual retainer ,
lateral cephalometric and panoramic radiographs taken at the end of treatment can be seen in figures 11 and 12 .
the maxillary first molars were distalized 3.5 to super class i molar relationship in 6 months ( u6-vr distance ) .
meanwhile , almost no anterior movement was observed in anchoring first premolars and upper incisor . since force application
was carried out via upper first premolars , slight anterior tipping of 3 was observed in upper first premolars .
mandibular plane angle decreased 1 ( sn -gogn ) during distalization and this change was still present at the completion of treatment .
upper lip was slightly retruded and the lower lip retained its position at the end of distalization .
total cephalometric superimposition ( sella - nasion plane at sella ) and local maxillary superimposition ( anterior nasal spine - posterior nasal spine plane at ans ) can be seen in figures 13 and 14 .
dental cast measurements showed that both of the upper premolars and first molar were rotated distopalatally .
slight expansion was observed in upper first premolar , second premolar and first molar widths ( figure 15 ) ( table 2 ) .
despite the successful use of conventional extraoral appliances for years , the need for compliance and their unaesthetic appearance made the need to search for alternatives .
the introduction of bone anchors in orthodontics has made a revolutionary change in fulfilling this need .
however a majority of the reports were based on records taken at the end of distalization .
anchorage preservation during retraction of the anterior segment is also quite important since some amount of the space gained is often lost during this stage . in the present case report
, treatment result was evaluated both at the end of distalization and at the end of treatment .
implants can be used as direct units for force application of they can be used to reinforce the anchorage teeth . in this case report , the upper first premolars were secured using a nance button to imf screw that was placed in anterior palatal region .
gelgor et al4 have used a similar appliance for anchorage reinforcement during molar distalization but the forces in their appliance were transmitted directly to the screw , which might cause the failure of the screws . in this case , the screw was not loaded directly ; an acrylic button was used to reduce the amount of force that the screw received .
gelgor et al4 have also found a similar rate of distalization in their controlled study .
karaman et al,11 krcelli et al16 and escobar et al17 have also achieved successful distalization results with different appliances that have reinforced their anchorage with the use of a palatally placed screw .
the distalization rate found in this case report was also similar to those that were found with conventional intraoral distalization appliances .
several authors that have used palatal screws for distalization have placed two screws and reported less tipping values.16,18 therefore we believe that a single screw is only sufficient for cases that need less amount of distalization .
the placement and removal of the screws are quite easy and well tolerated by the patients .
one major drawback of this kind of appliance is the need for removal of the appliance after distalization of second premolars .
the appliance should be replaced with a nance button or a transpalatal arch to free the first premolars and during anterior retraction , if needed .
however if a clinician aims to use the same implant supported appliance during incisor retraction , an osseointegrated implant or a zygoma anchorage will be the appliance of choice .
this kind of irritation was also reported with the use of a pendulum appliance and a nance button .
the ease in placement and removal , the possibility of immediate loading and positive toleration of the appliance by the patient are the main advantages of the appliance . however , long term evaluation after removal of all of the appliances should be made with a controlled clinical study . | ### Summary:
: the use of implants has made a major change in orthodontic treatment mechanics .
they have replaced conventional unaesthetic and compliance dependent extraoral appliances with well accepted intraoral mechanics .
implants can be used in molar and canine distalization , intrusion and in extraoral force applications . in the present case report , treatment of a case using an intermaxillary fixation screw ( imf )
will be presented .
the treatment results will be evaluated using pretreatment , post distalization and post treatment cephalometric radiographs and dental casts . |
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: a correctly balanced diet makes a major contribution to the wellbeing and healthy ageing of humans .
this is especially relevant in the case of people suffering from complex diseases , such as food allergy , involving diverse elements that constitute the intestinal ecosystem .
food allergy is a complex disease , influenced by phylogenic genes and environmental factors , and it represents an increasing concern to society with no cure available to date for this illness .
allergy to milk proteins is one of the major allergies , and even though it tends to diminish with age , it still concerns 1 - 2% of adults . since milk and milk proteins are consumed not only on their own but also serve as ingredients in a wide spectrum of food products , such as bakery and meat products , sweets , etc . , diets eliminating milk may negatively impact the quality of life end economy of food allergic consumers daily life .
adult people tend to look for beverages that may substitute cow s milk in their diet , such as rice milk .
this product contains no lactose and milk proteins , which makes it potentially attractive for people with intestinal disorders and an allergy to milk proteins . despite
the consumption of milk substitutes such as rice milk , knowledge on the impact of its protein fractions on the intestinal ecosystem is still very limited .
designing an optimal diet requires knowledge of the biological activity of food products , particularly in relation to people with food allergies .
a properly functioning intestinal ecosystem , which consists of microbiota and epithelium along with the immune system , plays an important role in maintaining the physiological equilibrium of the human body .
the small intestine is a critical niche of interplay between the external factors , such as food , and the internal environment constituting the human organism .
phenomena related with the interactions between the type of consumed diet , host cells , and autochthonic microbiota of the gastrointestinal tract ( git ) have been studied so far only partially . however , consumed food substrates undergo modifications due to enzymatic hydrolysis by proteinases present in the git
. the enzymatic degradation may lead to the alteration of biological activities displayed by initial protein fractions due to the release of highly bioactive peptides and glycopeptides .
such peptides may exert antibacterial , immunomodulatory , opioid - like , and hormone - like properties , etc .
. therefore , alterations in terms of the biological activity of food components caused by the hydrolysis process have to be taken into account while constructing the diet recommendations . peptides and glycopeptides released by the hydrolysis of proteins may significantly modulate the condition and activity of the intestinal ecosystem .
such substrates may interfere with adhesion of microbiota to the intestinal epithelium , and alter enterocytic metabolic and proliferative activity and the level of secretion of proinflammatory cytokines , thus influencing the intestinal barrier functionality and integrity and consequently determining the health - status of the consumer .
this is especially relevant in terms of people with an intestinal imbalance that occurs when a food allergy is present .
therefore , the aim of this study was to determine the effect of protein hydrolysates from rice milk substitute on the physiological response of the model of the small intestinal barrier of healthy and allergic people .
the small intestinal barrier was imitated by co - culture of caco-2 cells , representing enterocytes , ht-29-mtx cells , standing for goblet cells and bacteria immobilised to their surface . to address the scientific problem , bacterial representatives of the small intestinal region , such as lactobacilli , enterococci , and enterobacteria ,
were obtained from the faeces of healthy volunteers and ones suffering from an allergy to cow s milk , and they were used to build up models of the small intestinal barrier .
subsequently , the effect of hydrolysates from rice milk proteins exerted on the model was studied .
a commercially available rice milk powder product containing ( per 100 g of product ) 2.6 g of proteins , 70 g of carbohydrates , 21.3 g of fat , < 0.1 mg of cholesterol , and < 1 mg of gliadin was used / investigated in the study .
protein extraction was conducted according to the method described in the paper by witecka et al . .
extracted proteins were subjected to gastric and duodenal conditions according to the protocol previously described by mandalari et al . .
samples of hydrolysates used for experimental analysis were described as : rh substrates upon pepsin - pancreatin hydrolysis of proteins from rice milk .
the analysis was conducted as previously described in the paper by witecka et al . .
the small intestinal barrier model used in this study consisted of caco-2 cells , representing enterocytes , ht-29-mtx cells , representing goblet cells and intestinal bacteria , obtained from healthy and allergic people , which were adhered to the epithelial surface ( fig .
1 ) . such models were used to analyse the physiological response of epithelial cells ( metabolic and proliferative activity , il-8 secretion , transepithelial resistance , and gene expression ) and the adhesive potential of bacteria to rh hydrolysates .
small intestinal barrier models used in the study the study was divided into two modules : the adhesion experiment and the physiological response experiment ( fig .
2 ) . the schematic experimental design of the study small intestinal barrier models used for the adhesion experiment were cultured in the insert cultures .
however , three separate co - cultures were used for the physiological response experiment : to study the metabolic and proliferative activity and il-8 secretion ( standard plate cultures ) ; to study the gene expression ( standard plate cultures ) ; and to study the transepithelial resistance ( insert plate cultures ) .
faecal samples were obtained from seven healthy people and seven persons suffering from gastrointestinal disorders after consumption of cow s milk .
these volunteers were of both sexes at the age range of 18 - 55 years .
faecal samples were transferred into an anaerobic workstation ( don whitley scientific ) , where they were suspended in sterile peptone water ( ratio 1 : 10 w / v ) .
subsequently , the samples were homogenised for three minutes with glass beads ( 5 mm diameter ) and afterwards serially diluted 10-fold .
100 l of particular dilution was transferred onto the solid media in order to obtain single colonies .
various solid media were used in the experiment in order to obtain particular bacterial isolate : rogosa medium for isolation of lactobacillus ( lac ) , macconkey medium for enterobacteriaceae ( ent ) , and kea ( kanamycin esculin agar ) medium for enterococcus ( entcc ) .
these bacterial groups were selected as the main representatives of microorganisms colonising the human small intestine .
plates were incubated at a temperature of 37c aerobically or anaerobically depending on the bacterial oxidative requirements .
after incubation , single colonies , chosen on the macro- and microscopic basis , were collected and suspended in a sterile , anaerobic pbs buffer . from each medium ( from seven volunteers )
the cultures were centrifuged at 10,000 rpm for five minutes , and the obtained pellets were resuspended in 1 ml of sterile , anaerobic pbs buffer .
such bacterial suspensions were used to prepare bacterial solutions ( bs ) as follows : heterogeneous - bacterial isolate solution ( mix ) : 70 l of each bacterial isolate ( ent , entcc , lac ) was transferred into the 20 ml dmem medium without antibiotics and used subsequently in the experiment .
caco-2 is derived from the absorptive cells and therefore functions as a model of the small intestinal enterocytes , whereas ht-29-mtx stems from the goblet cells and thus mimics the mucus - producing intestinal cells .
these two cell lines were used as a small intestinal model by being grown together in a co - culture , as described previously by laparra and sanz .
both of them were obtained via sigma aldrich from the european collection of cell cultures and were routinely cultivated in the filtrated dmem medium ( dulbecco s modified eagle s medium , sigma ) containing 20% of inactivated foetal bovine serum ( fbs , gibco ) , 1% of non - essential amino acids mixture ( neaa , gibco ) , and 0.1% of penicillin - streptomycin solution ( sigma ) .
the incubation was carried out at 37c in 5% co2 atmosphere with humidity approximately 95% .
caco-2 cell line was used in passage number 47 , whereas ht-29-mtx was used in passage number 53 .
caco-2 and ht-29-mtx were seeded together at a ratio of 9 : 1 , to mimic the conditions in the small intestine .
for adhesion experiments and permeability study , the cells were seeded in dimensional cultures onto hanging inserts of pore size 0.4 m and inner diameter 12 mm ( millipore , merck , poland ) , and placed in the 12-well tissue culture plates ( becton dickinson ) at a density 50,000 cells per cm . for the physiological response experiments , caco-2 and ht-29-mtx
were seeded together at the same ratio and cell density in 96-well plates ( becton dickinson ) .
cultures were cultivated for 21 days , to reach their full differentiation , and the medium was changed every second day .
at least 24 hours before the test , the dmem medium supplemented with penicillin - streptomycin was replaced with the same medium without the antibiotic and the incubation of the cultures was continued .
the caco-2/ht-29-mtx dimensional co - cultures were incubated with 300 l of the analysed rh hydrolysate solution at the final concentration of 0.5 g / ml for two hours at 37c in an atmosphere of co2 and humidity approximately 95% .
cultures without any substrate supplementation were treated as controls ( c ) . after the incubation ,
the co - cultures were respectively supplemented with 300 l of heterogenous - bacterial isolate solution , prepared as described in the section : bacterial isolates and growth condition .
the co - cultures were subjected to a further two - hour incubation . after the incubation
, the media were removed from the apical side of the chamber and the co - cultures were washed twice with warm , sterile pbs supplemented with 1 mm of cacl2 and 1 mm of mgcl2 to remove non - adherent bacteria . to liberate the adhered bacteria from the caco-2/ht-29-mtx surface
, the cultures were incubated on ice for 10 minutes with 300 l of 0.1% cold triton x-100 solution ( sigma ) .
subsequently , bacteria were subjected to dapi and dope - fish staining procedures , as described below , in order to assess the total number of adhering bacteria and the number of adhering lactobacilli / enterococci ( lab ) and enterobacteria ( ent ) .
shifts in the total bacterial number , caused by exposition to the tested rh hydrolysates , were estimated with dapi staining according to the procedure described previously by witecka et al . .
bacterial cells were counted using fluorescent in situ hybridisation with double labelling of oligonucleotide probes ( dope - fish ) , according to the protocol described by rycroft et al . .
the probes were used as follows : lab158 specific for lactobacillus / enterococcus spp . and ent1432 specific for the bacteria from the enterobacteriaceae family .
the hybridised mixture was subsequently filtered through a 0.2-m membrane filter ( millipore ) , and bacterial cells were counted using an epifluorescence microscope ( olympus bx53 ) and the automatic multiscan programme for the image analysis .
the co - cultures used in the physiological response experiment are explained on the diagram below ( fig .
a co - culture of caco-2 , ht-29-mtx , and bacteria of different origin was used in order to imitate the small intestinal barrier of healthy and allergic people .
co - cultures of caco-2 and ht-29-mtx cells , seeded in 96-well plates , were exposed to 100 l of heterogeneous bacterial solution and incubated for two hours to allow the bacteria to adhere .
co - cultures cultivated without bacteria were treated with 100 l of dmem without antibiotics .
afterwards , the non - adherent bacteria were removed by double pbs washing , and subsequently 100 l of analysed hydrolysates at a final concentration of 0.5 mg / ml were supplemented to the co - cultures .
all co - cultures were incubated for subsequent two hours and subsequently subjected to tests : wst-1 , brdu test , and elisa method ; real - time pcr and teer ( described below ) .
additionally , alike cultures were conducted to study the impact of rh hydrolysates on the gene expression .
similar cultures with comparable experimental design were conducted in inserts to assess the impact of rh hydrolysates on transepithelial resistance .
the analyses were carried out after two - hour incubation by adding 10 l of the wst-1 reagent ( roche ) .
samples with the wst-1 reagent were incubated for one hour at 37c with slight , constant agitation . at the end of the incubation
the absorbance was measured at = 450 nm . a sample containing the medium and the wst-1 reagent without any hydrolysate supplementation was treated as a control , whereas a culture containing the growth medium with sds was a negative control sample .
the control sample was treated as 100% and the obtained results were referred to it .
cells were incubated in the presence of examined hydrolysates at a concentration of 0.5 mg / ml for two hours .
after labelling , brdu incorporation into cellular dna was measured by colorimetric immunoassay using a commercially available cell proliferation elisa kit ( roche , france ) .
absorbance from peroxidase reaction with opd ( o - phenylenediamine dihydrochloride ) substrate was measured by a scanning multi - well spectrophotometer at 492 nm .
brdu incorporation for all experiments was expressed as the percentage in comparison to the control , which was calculated as 100% .
after the second incubation step , the cell layers were washed two times with pre - wormed pbs .
cytokine production ( pg / ml ) was compared with the results obtained for cells incubated in the control medium .
the content of il-8 in media was measured using a commercially available elisa according to the manufacturer s instructions ( bd biosciences , opteia , pharmingen , san diego , ca ) . in order to assess the in vitro permeability of the caco-2/ht-29-mtx cell lines monolayer , the dimensional culture on hanging inserts
was carried out in parallel under the same conditions as described above . at the end of the experiment ,
measurement of the monolayer transepithelial electrical resistance was conducted with teer ( millipore , merck , poland ) .
after defrosting , the cells were washed with sterile , rnase free pbs and proceeded as described in the protocol of the genematrix universal rna purification kit ( eurx , gdask , poland ) .
the quality and concentration of isolated rna was checked spectrophotometrically ( picodrop , nanovue ) .
real - time pcrs were conducted by a mastergradient cycler ( eppendorf , warsaw , poland ) in total volume of 25 l .
reaction mixtures consisted of 12.5 l of sybrgreen jump start ( sigma ) , 1 l of the reverse transcribed rna , 1 l of each primer , and pcr - grade water ( sigma ) .
the control was the model of the small intestinal barrier , consisting of caco-2/ht29mtx / bacteria co - culture .
statistical analysis of the results obtained were conducted with the use of statistica 9 software .
the statistical significance was determined by the variance analysis using the f distribution by fisher .
figure 3 shows the electrophoretic separation of the proteins from rice milk substitute digested by two - step hydrolysis with pepsin / pancreatin .
kinetics of hydrolysis of proteins from rice milk substitute ( r ) ; i pepsin digestion phase , ii pancreatin digestion phase the proteins from the rice milk substitute were digested in the 70% ( fig .
4 ) . degree of hydrolysis proteins from rice milk substitute and rg of proteins from rice milk substitute digested in the presence of glucose the presence of the microbial layer , consisting of bacteria obtained from healthy people , altered the response of small intestinal cells when exposed to rh hydrolysates , by increasing the number of proliferating cells and decreasing the secretion of il-8 in comparison to the co - culture ( fig .
however , the observed decrease in the il-8 secretion had no statistical relevance when compared to the control culture .
rh hydrolysates had no statistically relevant impact on the transepithelial transport in the cultures with adhered bacteria from healthy people ( fig .
impact of hydrolysates of proteins from rice milk substitute ( rh ) on the physiological response of small intestinal cells ( caco-2/ht-29-mtx ) in terms of : a ) metabolic activity , b ) proliferative activity , c ) il-8 secretion , d ) transepithelial resistance hydrolysates caused an increase in the metabolic and proliferative activity compared to the control ( fig .
in addition , the presence of bacteria from allergic people in culture supplemented with rh triggered an increase in il-8 secretion when compared to the culture with bacteria from healthy people ( fig .
analysed hydrolysates had no impact on the total number of adhering bacteria ( tbn ) in mixed suspension obtained from healthy people ( fig .
6a ) . whereas they stimulated the total number of adhering bacteria in mixed suspension obtained from allergic people in the caco-2/ht-29-mtx co - culture ( fig .
regardless of the total number of bacteria adhering to small intestinal cells , analysed hydrolysates had no impact on the profile ( proportions ) of adhering bacteria regardless of their origin , leaving lactobacilli / enterococci more abundantly immobilised in comparison to enterobacteria ( fig .
rh on the adhesion of mixed bacterial suspension consisting of enterobacteriaceae , lactobacillus / enterococcus to the surface of caco-2/ht29mtx cells .
a ) bacteria obtained from healthy people ; b ) bacteria obtained from allergic people analysed hydrolysates stimulated the expression of tlr2 gene in the caco-2/ht-29-mtx co - culture with bacteria from healthy people ( fig .
rh on the expression of tlr2 gene in the caco-2/ ht29mtx cells with adhered bacteria obtained from : a ) healthy people ; b ) allergic people\ an opposite effect was exerted by the analysed hydrolysates on the expression of nfb gene in caco-2/ht-29-mtx cells with bacteria from various origin , displaying a significant decrease in the cultures with bacteria from healthy people ( fig .
8a ) and an increase in the co - culture with bacteria from allergic people ( fig .
. impact of hydrolysates of proteins from rice milk substitute on the expression of nfb gene in the caco-2/ht-29-mtx cells with adhered bacteria obtained from : a ) healthy people , b ) allergic people summarising , the analysed hydrolysate stimulated all of the examined parameters in the intestinal barrier model with bacteria from allergic people , increasing epithelial cells metabolic and proliferative activity , il-8 secretion , and transepithelial resistance ( fig .
schematic summary of impacts exerted by rh hydrolysates of proteins from rice milk on the caco-2/ht-29-mtx cell lines co - culture and on adhesion of bacteria in the models with bacteria from healthy ( a ) and allergic people ( b ) whereas the analysed hydrolysate stimulated solely the epithelial proliferation and transepithelial electric resistance , with no impact on the metabolic activity and il-8 secretion ( fig .
the rh hydrolysates exerted an opposite effect in terms of nfb expression by epithelial cells , inhibiting it in the co - culture with bacteria from healthy people and stimulating in the co - culture with bacteria from allergic people ( fig .
rh hydrolysate stimulated the expression of tlr2 gene in the eukaryotic cells with immobilised bacteria from healthy people and had no impact on its expression in the co - culture with bacteria from allergic people ( fig .
. schematic summary of impacts exerted by rh hydrolysates of proteins from rice milk substitute on the expression of genes ( tlr2 and nfb ) by caco-2/ht29-mtx cell lines co - cultures with adhered bacteria from healthy ( a ) and allergic people ( b )
food proteins that are consumed undergo modification due to enzymatic hydrolysis by proteinases present in the git , which may lead to the alteration of biological activities displayed by initial protein fractions by the release of highly bioactive peptides and glycopeptides .
enzymatic hydrolysis alters the protein structure , thus modifying its biological activities targeting health effects .
it is therefore crucial to take into account the interplay between the small intestinal ecosystem and hydrolysates released by hydrolysis in shaping proper physiological condition of the local small intestine environment as well as on the health status of a consumer , while constructing diet recommendations .
reaching the small intestine , the place of final nutrient degradation and absorption , peptides and glycopeptides act as modulators influencing both the bacteria colonizing this niche , and the eukaryotic cells creating epithelium , which together make up the intestinal barrier .
the intestinal barrier is a critical interface between the organism and the environment , guarantying selective permeability , protecting against detrimental factors , and influencing local homeostasis .
various in vitro models are being used in order to study the physiological status of epithelial cells as well as bacterial adhesion .
most often , such models consist of a single cell line , mainly caco-2 , to imitate the morphology and physiology of the most abundantly present cells : enterocytes . however , the intestinal barrier is a highly complex structure , consisting also of cells secreting mucus and bacteria that are attached to their surface .
for that reason , a model consisting of a double cell line culture , encompassing absorptive cells and mucus secreting cell ( caco-2 and ht29-mtx ) , was applied to assess the biological effect of analysed hydrolysates as well as the mentioned co - culture with bacteria typical for the small intestinal region of different origin ( from healthy and allergic people ) , which were adhered to mentioned epithelial cells .
the used cell lines are aimed to retain the phenotypic properties of their progenitors and committed proliferative , differentiated cells to design and maintain the controlled environment .
enterocyte turnover and their optimal physiological status are highly regulated processes to much extend influencing the predisposition to an intestinal inflammation and a number of gastrointestinal diseases , including ibd and food allergy .
however , the intestinal barrier consists not only of eukaryotic cells , such as enterocytes and goblet cells , but also is reinforced by microorganisms attached to their surface .
contact with such immobilised bacteria and/or their products impact the epithelium s turnover , secretive activity , maturation , integrity , and other vital functions .
in addition , it impacts the thickness of the intestinal barrier , which is relevant to its physiological function . for microorganisms ,
adhesion in a mobile environment such as the small intestine , is crucial and enables them to anchor and benefit from the nutritional richness available in this region .
interestingly , when the small intestinal barrier was built up of caco-2/ht-29-mtx cells and immobilised bacteria obtained from healthy people , the response of epithelial cells to rh hydrolysate shifted significantly in terms of all of analysed parameters , increasing their mitosis ( fig .
5b.1 ) , and decreasing the il-8 secretion when compared to the control culture ( fig .
that is in accordance with the statement that luminal bacteria signal the interfacing epithelial layer and control the turnover rate of enterocytes , thus fortifying the epithelial regenerative and barrier functions .
consequently , it may positively impact the enterocyte turnover and self - repair , thus having a potentially beneficial effect on the intestinal barrier s status of healthy consumers .
the diminished il-8 secretion may also suppress the immunological response , thus holding back the development of the inflammatory status and barrier impairment .
interestingly , the analysed hydrolysates had no effect on the epithelial integrity in the intestinal barrier model with bacteria from healthy people , thus suggesting the neutral effect of these microorganisms in that aspect ( fig .
a healthy gut remains nonresponsive to a multitude of food antigens and commensal and transient bacteria with an intestinal barrier as a critical factor promoting the differentiation of tolerogenic phenotypes of dendritic subsets , thus implying the importance of local homeostasis for oral tolerance status .
the link between disruption in the intestinal barrier functionality and permeability with food allergy is widely accepted , highlighting the importance of epithelial cell integrity , cell shedding , and their activation in terms of chemokine release .
a channelled diet - manipulation in terms of consumers suffering from food allergies is therefore crucial in order to avoid triggering the inflammatory status to be more acute and/or to exert health - promoting effects .
it is noteworthy that the presence of bacteria isolates from allergic people attached to the epithelial surface along with the presence of examined hydrolysates radically altered the nature of the epithelia s response , triggering the stimulatory effect of proliferation ( fig .
5b.2 ) , metabolic activity ( fig . 5a . ) , il-8 secretion ( fig .
this response differs from the one observed when bacteria from healthy people constituted the intestinal barrier ( fig .
once again , this highlights the importance of cooperation between commensal microbiota and the epithelial cell layer in the aspect of intestinal barrier physiological status .
the presence of bacteria from allergic people immobilised to epithelial surface along with rh hydrolysates tunes on the level of proinflammatory cytokine secretion .
such an effect may result in the recruitment of further immune - competent cells in the vicinity of the intestinal mucosa and an ensuing increase of the inflammatory cascade . that may possibly negatively influence the trophic status of the intestinal barriers of people suffering an allergy to milk proteins upon consumption of rice milk or sweetened rice milk .
enterocytes undergo apoptosis and exfoliation as they reach the small intestinal villus tip , and thus , by their shedding , ensuing epithelial renewal and protective function . the increased proliferative activity ( fig .
5b.2 ) suggests the impact of rh hydrolysates and/or bacteria from allergic people to influence the self - renewal process . however , under inflammatory conditions , epithelial proliferation and turnover are accelerated , thus increasing the risk of barrier leakage and excessive bacterial translocation , which may induce strong inflammatory responses . on the other hand ,
being exposed to multiple allergens , epithelial cells are prone to damage , and therefore the increased proliferative activity of epithelial cells along with the proper control of their shedding may be beneficial for epithelial cell self - renewal .
the stimulated metabolic activity of epithelial cells suggests their enhanced vital activation , implying their readiness , which may be crucial in terms of fast responses to antigens .
the presence of bacteria from allergic people immobilised to the epithelial surface increased its transepithelial resistance in the environment of the analysed hydrolysates ( fig .
5d.2 ) , thus suggesting the increase of the barrier s integrity , which may be a protective response to the local environment shaped by the allergic condition .
however , a separate study is needed to examine the impact of microbiota from healthy and allergic people on the physiological status of the intestinal barrier .
the environment of the human small intestine is subjected to the constant action of food products , potential allergens , which are decomposed and absorbed in this region , simultaneously influencing bacterial adhesive potential .
adhesion is one of the bacterial strategies indispensable for colonisation of the small intestine and plays a pivotal role in shaping the functionality of small intestinal epithelium , and in influencing the thickness and functionality of the intestinal barrier . considered as beneficial , lactic acid bacteria from both healthy and allergic people adhered more abundantly in comparison to enterobacteria , which is a probable result of their adhesive potential determined by specific adhesins accompanied with their ability to compete for receptor sites .
such a tendency may result from a mutual interaction between bacteria and eukaryotic cells aimed at optimisation of the intestinal barrier health status ; nevertheless , it requires in vivo confirmation .
the rh hydrolysates had no effect on the profile of adhering bacteria from healthy people , remaining lactobacilli / enterococci most abundantly immobilised to the epithelial surface , as in the control culture ( fig .
lactobacilli have been shown to increase tight junction protein expression , consequently restoring intestinal permeability .
the fact that the total number of adhering bacteria was not altered by the analysed hydrolysates , nor their profile , may indicate the stability of the intestinal barrier , thus remaining the most abundantly anchored lactic acid bacteria , and that they may potentially exert a beneficial effect by their protective function and metabolic activity .
bacterial adhesion is thought to play a role in the maintenance of the mucus layer by influencing the number and size of mucus secreting goblet cells .
the mucus cover in turn is relevant in terms of trapping unwanted bacteria and thus protecting from the excessive microbe passage through the intestinal barrier .
luminal bacteria are recognised by the extracellularly located part of tlrs , leading to activation of nfb .
tlr-2 is activated by peptidoglycan , a part of the cell wall of gram - positive bacteria , and its activation leads to phosphorylation of protein kinase c , with a subsequent decrease of intestinal permeability .
this decrease in permeability is proposed to be the result of changes in tight junctions .
the rh hydrolysates of proteins from rice milk stimulated the expression of tlr2 in epithelial cells co - cultured with bacteria from healthy people ( fig .
7a ) , implying an increase of the barrier s integrity , potentially beneficial for rice milk consumers .
interestingly , such an epithelial response was not observed in the case of intestinal barrier co - built with bacteria from allergic people .
the expression of tlr2 in these cultures was significantly lower when compared to the co - cultures with bacteria from healthy people ; this requires further studies to unravel the underlying mechanism .
nfb is a protein complex causing inflammation in the body by influencing proinflammatory cytokine secretion .
nfb is a rapid - acting transcription factor , with no requirement of additional proteins for its activation , thus being a first responder to detrimental stimuli .
many bacterial products and stimulation of a wide variety of cell - surface receptors lead to nfb activation and fairly rapid changes in gene expression , and a resulting control of low - inflammatory tone and epithelial repair .
the beneficial quieting of the nfb in epithelial cells by both of the analysed hydrolysates was demonstrated in the co - culture with bacteria from healthy people , thus suggesting a beneficial effect .
however , the presence of the analysed hydrolysates in the culture with bacteria from allergic people triggered the increase of nfb expression , thus implying a potentially unfavourable response , especially in the case of allergic people .
since nfb is a factor involved in the signal transduction via multiple pathways and thus is regulated by various factors , the observed outcome should be scrutinised in a broader manner , taking into account the systemic response in the in vivo model .
bacteria inhabiting the intestinal niche alter the physiological response of epithelial cells to the hydrolysates from rice milk depending on their origin from healthy or allergic people . with regard to an environment with epithelial cells and bacteria from healthy people adhered to their surface , rice milk protein hydrolysates seem to exert a potentially positive effect by influencing the proliferative activity and decreasing the secretion of proinflammatory il-8 .
however , in terms of the environment consisting of epithelial cells and bacteria from allergic people adhered to their surface , the hydrolysates from rice milk proteins may trigger a potentially detrimental effect due to increased il-8 secretion and increased mitotic activity , which , under inflammatory conditions , accelerates epithelial proliferation and turnover , thus increasing the risk of barrier leakage and excessive bacterial translocation , which may induce strong inflammatory responses . | ### Summary:
: designing an optimal diet requires knowledge of the biological activity of food products , particularly in relation to people with food allergies . the hypothesis , which constitutes the basis of this thesis , states that the peptides and glycopeptides released from proteins by enzymatic hydrolysis are able to change the quantity and quality of the human gastrointestinal ecosystem . such substrates may interfere with adhesion to the intestinal epithelium microbiota and alter enterocytic metabolic activity .
the aim of this study was to determine the effect of protein hydrolysates from rice milk substitute on gut epithelial cells and the intestinal microbiota of healthy people and ones suffering from an allergy to milk .
the following experimental work applied systems that reflect the conditions occurring in the gastrointestinal tract . |
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: because a safe and effective hiv-1 vaccine remains an elusive goal , the basis for current vaccine strategies must be revisited .
although the immune system never successfully clears hiv in natural infection , the potential to contain the virus for decades through cytotoxic t cell ( ctl ) responses has been demonstrated in a minority of patients with rare human leukocyte antigen ( hla ) variants , particularly hla - b2705 , -b5701 , -b5703 , and -b5801 ( goulder and walker , 2012 ) .
the respective frequencies of these hla variants are 0%14% , 0%11% , 0%3% , and 0%2% in whites and 0%5% , 0%6% , 0%8% , and 0%14% in africans ( gonzalez - galarza et al . , 2011 ) .
these hla molecules present key fragments ( cd8 epitopes ) of the hiv-1 capsid protein p24 gag on the surface of infected cells to enable immune recognition and killing by ctl ( dahirel et al . , 2011 , dinges et al .
pereyra et al . , 2010 ) , the reason these particular ctl responses are strongly linked to delayed disease progression is not fully understood .
in addition to these protective ctl responses , there is an association between ctl responses against p24 gag and lower mean viral loads in patients ( kiepiela et al . , 2007 ) .
hla - b rather than the less diverse hla - a or hla - c restricts most of these responses although the underlying mechanism is unclear ( goulder and walker , 2012 , kiepiela et al . , 2004 ) .
the current paradigm is therefore that relatively few hla variants are associated with reductions in viral load and so impose a significant selective pressure on hiv ( matthews et al . ,
antigen processing is one crucial step in the pathway responsible for hla presentation of hiv epitopes to ctl .
it is a multistep process , where viral proteins synthesized in infected cells are first degraded by cytosolic proteasomes .
the proteasomes appear in constitutive and interferon ( ifn)--inducible immunoproteasomal forms ; the latter is normally expressed in lymphoid and antigen presenting cells but can be induced in other cell types during hiv infection ( kloetzel , 2001 , tenzer et al . , 2004 , toes et al . , 2001 ) .
proteasomal cleavage products ( epitope precursors ) might be further digested by cytosolic peptidases before the transporter - associated - with - antigen - processing ( tap ) transfers them into the endoplasmatic reticulum ( er ) . here
, they undergo n - terminal trimming by the er aminopeptidases ( erap1,2 ) and are loaded onto any restricting hla class i molecules with suitable anchors .
all ctl responses can select for mutations within or flanking cd8 epitopes that allow hiv to escape ctl recognition .
these mutations may affect hla binding , t cell receptor ( tcr ) contact sites , and/or antigen processing ( draenert et al .
, 2004 , goulder and walker , 2012 , iversen et al . , 2006 , tenzer et al . , 2009 , zhang et al . , 2012 ) .
escape mutations might confer reduced viral fitness by coincidentally increasing epitope processing ( tenzer et al . , 2009 ) and/or reducing viral replication or infectivity ( goulder and walker , 2012 ) .
such mutations typically revert following transmission to hla - mismatched recipients ( reverting mutations ) , whereas mutations with no fitness cost persist ( nonreverting mutations ) ( matthews et al . , 2008 ) .
the most effective ctl responses select for reverting escape mutations ( matthews et al .
, 2008 ) , and the accumulation of these mutations at the viral population level due to factors such as compensatory mutations might therefore affect hiv control ( kawashima et al . , 2009 ) .
nonreverting escape mutations are not associated with viral load reductions but might accumulate and eventually replace the wild - type population .
this evasion of immune responses is so advantageous to hiv that positive selection of escape mutations drives hiv evolution within hosts ( rambaut et al . , 2004 ) .
following hiv transmission , 35% of gag substitutions in the recipient is associated with hla - mediated selection , and 70% of these are reversions ( brumme et al . , 2008 ) .
however , the extent to which hiv evolves at the population level in response to immune pressures is a matter of debate because of other influences , such as the founder effect ( the random initiation of epidemics in uninfected areas by a single or a few individuals hiv lineages ) , transmission bottlenecks that reduce genetic diversity , and variation in the rates of partner exchange involving sexual transmission .
bioinformatics studies have shown that many polymorphisms in hiv are associated with particular host hla class i alleles ( bhattacharya et al . , 2007 ) ; however , the impact of these changes on antiviral immune responses is often unclear , and evolution among hosts is dominated by genetic drift ( rambaut et al . , 2004 ) .
globally , hiv-1 forms geographically distinct clusters , known as subtypes , which are labeled alphabetically .
these subtypes are believed to be caused by founder effects ( rambaut et al . , 2004 ) .
we and others have previously demonstrated that the amount of epitopes made following in vitro proteasomal digestions correlate with the magnitude and frequency of in vivo ctl responses ( lazaro et al . , 2009 , schmidt et al . , 2012 , tenzer et al . , 2009 ) , and studies have shown that epitope - specific ctl recognition increases with increasing epitope production and/or concentration ( almeida et al . , 2007 , ranasinghe et al . , 2011 , zhang et al . , 2012 ) .
because of these correlations , hiv sequence combinations that minimize or eliminate cd8 epitope production through adaptation to conserved antigen - processing preferences ( paulsson , 2004 ) would potentially be a very efficient immune escape mechanism if they were to occur .
here , we hypothesized that hiv adaptation to antigen - processing preferences might limit cd8 epitope production at the viral population level in a manner dependent on the hla allele frequency within a host population , thereby reflecting the sum of all intrapatient adaptations and their transmissibility .
to investigate the regulation of cd8 epitope production at the viral population level , we studied the proteasomal processing of hiv subtypes b ( hiv b ) and c ( hiv c ) ; hiv b predominates in western europe and the us and accounts for approximately 11% of all infections worldwide , whereas hiv c prevails in sub - saharan africa and is responsible for approximately 50% of infections ( buonaguro et al . , 2007 ) .
we focused on p24 gag and concentrated on the two conserved regions that dominate the clinically effective hiv - specific ctl response in patients infected by either hiv subtype ( fragments 1 [ f1 ] and 2 [ f2 ] , figure 1a ; goulder and walker , 2012 ) .
the key p24 regions contain clusters of partially overlapping cd8 epitopes , including the only four cd8 epitopes that are strongly associated with delayed disease progression and 52 other epitopes that have no association with disease development and are rarely recognized ( table s1 ) ( dinges et al . , 2010 ,
three of the beneficial epitopes are presented by hla - b5701 and -b5703 ( iw9 , kf11 , and tw10 ) , and one is presented by hla - b2705 ( kk10 ) ; kf11 and tw10 may also be presented by hla - b5801 and -b63 , and iw9 is also presented by hla - a25 , -b63 , and -cw06 ( figure 1a ; table s1 ) .
kf11 also encodes a shorter epitope form , ki8 ( goulder et al . , 2000 ) , presented by the same hla variants .
the nonprotective epitopes are presented by 30 hla class i variants , and , similar to three of the protective epitopes , many can be presented promiscuously by more than one hla variant ( frahm et al . , 2007 ) .
these regions also contain five subtype - specific substitutions that are situated either between or within the epitope clusters ( figure 1a ; [ subtype bc ] vi and st in f1 ; ga , ns , and ed in f2 ) . to test the hypothesis
that hiv adaptation to escape ctl responses may limit the production of viral epitopes in a manner dependent on the hla class i allelic frequency within a host population , we first generated proteasomal digestion data .
we designed overlapping hiv b and hiv c peptides ( figure 1b ) , digested these with purified human constitutive proteasomes and immunoproteasomes , and analyzed the resulting fragments by mass spectrometry as in tenzer et al .
( 2009 ) . whereas proteasomal digestion produces the carboxyl ( c)-terminal end of most epitopes , several aminopeptidases in the cytosol and the er can trim the amino ( n)-terminal peptide extensions ( van endert , 2011 ) .
therefore , we aligned the digestion fragments with reported cd8 epitopes and defined an epitope precursor as a peptide fragment that contained the correct c terminus of an epitope but could be extended by one or several residues at the n terminus . although most known cd8 epitopes are defined as optimal epitopes ,
i.e. , the artificially synthesized epitope - peptide form that elicits the greatest ctl responses in vitro , we found that most epitopes were processed as epitope precursors with n - terminal extensions ( table s1 ) .
for each epitope , the intensities of the epitope precursor(s ) and the optimal epitope were combined for the calculation of the total epitope production of a given epitope ( epitope yield ) . occasionally ,
two or more epitopes , presented by different hla class i variants , shared the same c - terminal end but differed with respect to the start of the n terminus ; such epitope - precursor fragments would be analyzed on their own .
we next used scatterplots to illustrate the relationship between hiv b or hiv c epitope yields and the hla allelic frequencies of epitope - presenting hla variants in six white and six sub - saharan populations predominantly infected with hiv b or hiv c , respectively ( figure 1c ) .
if a given epitope - precursor fragment contained a promiscuously presented epitope and/or more than one epitope , we summed the frequencies of all hla variants that could present the epitope(s ) encoded by that epitope precursor .
the abundance of epitope precursor fragments containing the protective epitopes iw9 , kf11/ki8 , or kk10 correlated with the summed frequencies of the presenting hla variants , whereas the production of tw10 was less than expected considering that the hla - driven selective pressures on tw10 and kf11 are similar ( figure 1c ) .
however , tw10 differs in two important respects from kf11 : first , most of tw10 is included in epitopes presented by the common hla - a02 variant , and the combined selective pressures may further reduce tw10 processing , and second , the cytoplasmatic peptidase stability of tw10 ( t1/2 = 31 min ) is far greater than that of kf11 ( t1/2 = 13 s ) and most other epitopes ( lazaro et al . , 2011 ) .
because of this , the selective pressure to reduce the production of tw10 might be stronger than for kf11 .
subsequently , we took within - population correlation into account by fitting a multilevel linear model to examine the influence of the presenting hla allelic frequencies , hiv region ( nf1 , cf1 , mf2&cf2 ) , and ethnic group ( africans , whites ) on epitope yield ( table s2 ) .
this analysis demonstrated a significant three - way interaction among fragment , hla frequency , and ethnic group on epitope yield .
a strong relationship between epitope yield and hla allelic frequency was found for nf1 , cf1 and mf2&cf2 ( figure 1d ) , but , whereas similar variation in hla frequency had similar effects on epitope yields in nf1 and mf2&cf2 regardless of ethnic group , a significant difference between ethnic groups was found with respect to cf1 ( p < 0.0001 ) . as shown in the graph ( figure 1d , cf1 ) , identical hla - mediated selection pressures in africans and whites were typically associated with lower hiv c than hiv b epitope yields , especially at low hla allelic frequencies ( p < 0.0001 ) .
specifically , at an hla allelic frequency of 0.05 ( equivalent to hla variants found in 10% of the population ) , the epitope yields from hiv c were only approximately 25% of those of hiv b ( figure 1d , cf1 , dashed line ) .
the lower epitope yields might reflect a combination of a greater adaptive potential of this region in hiv c , differences between african and white hla alleles , a bias in the database toward hiv b epitopes , and/or the longer history of the hiv epidemic in africa .
we next fitted the same model to epitope yields from the constitutive proteasomal digestions and found similar patterns ( t test , p = 0.390.95 ) ( table s2 ) . as a result of the hla - mediated adaptation of hiv to proteasomal preferences ,
the cd8 epitopes presented by rare hla variants are produced in greater quantities than those presented either by common variants or by a combination of rare and common variants and might therefore be more likely to prime ( faroudi et al .
, 2003 ) and/or be recognized by ctl ( purbhoo et al . , 2004 ) .
collectively , our data provide compelling evidence that these clinically important p24 hiv gag regions adapt to proteasomal preferences at the population level in response to selection pressures that are imposed by all epitope - restricting hla class i variants in an hla frequency - dependent manner . to examine how tap
transport and erap trimming preferences might affect the predicted epitope presentation and recognition at the cell surface , we tested the subset of epitope precursors with the protective iw9 , kf11 , ki , or tw10 motifs ( figure 2a ) . to induce a ctl response ,
the epitope - precursor fragments must first be transported by tap into the er , and , because tap transport rate is determined by binding , not translocation ( gubler et al . , 1998 ) , we measured the normalized tap affinities of the precursors ( figure 2b ) .
tap binding affinity was sequence but not length specific , given that tap sometimes bound long epitope precursors ( > 16 amino acids ) better than shorter peptides containing only parts of the longer sequence ( e.g. , af19 versus vf14 and vf15 , figure 2b ) . overall , most precursors were transported well , especially those produced in the greatest abundance ( affinity < 50 ) . following tap transport ,
epitope precursors associate with hla molecules , and the n - terminal part of the peptide may be trimmed by erap before or after binding ( van endert , 2011 ) .
furthermore , internal subtype - specific amino acid differences could affect n - terminal trimming rates and thus affect the repertoire of trimmed epitope - containing fragments and the production of optimal epitopes ( figures 2c and s1 ) .
specifically , the optimal tw10 epitope was observed only following erap trimming of the rw18 precursor from hiv b , not hiv c , because of a single amino acid variation at position 9 within the epitope ( position 17 within the 18-mer precursor , figure 2c ) , and the optimal kf11 epitope was undetectable due to rapid degradation ( figure s1 ) .
however , functional analyses of cd8 t cell responses in four untreated hiv - positive patients with hla - b5701 ( table s3 ) demonstrated that the patients could recognize different length variants of the same epitope and that recognition often resulted in polyfunctional cytokine responses ( figure 2d ) .
taken together , our tap , erap , and ctl - recognition data suggest that proteasomal digestion preferences often produce fragments that accommodate tap binding preferences , that most epitope precursors are transported well into the er , that a fraction is trimmed to shorter epitope precursors and optimal epitopes and that patients can recognize a variety of epitope - peptide forms .
thus , the observed differences in proteasomal epitope abundance appear to reflect differences in predicted epitope abundances on the cell surface .
next , we investigated whether the inverse correlation between the hiv b and hiv c cd8 epitope yields and the frequency of the presenting hla variants in the infected populations reflected the sum of individual adaptations within patients . to investigate intrahost viral adaptation , we combined bioinformatics analyses of hiv sequences from hla - typed patients infected with either hiv b or hiv c with processing analyses of 22 peptides containing all of the possible permutations of the consensus sequences of the two subtypes ( figure 3 ) .
each variant differed by only one amino acid from the next , and , whereas some substitution patterns were observed at a high frequency in vivo , other patterns were rare ( table 1 ) .
we used subtype - permutated peptides because sequence variations in both p24 regions usually occur at the subtype - specific positions ( figure s2 ) and because changes typically occur to the preferred amino acid in the other subtype ( figure s3 ) . in the minority of patients able to present the protective iw9 , kf11 , tw10 , or kk10 epitopes , additional variation
could sometimes be found at positions associated with well - described ctl - escape mutations ( e.g. , ap [ iw9 ] , tn [ tw10 ] , table s4 ) .
we compared variations in epitope - abundance for every epitope in f1 and f2 with the specific amino acid that was selected for at subtype - specific positions in hiv isolated from patients with hla variants able to present each epitope ( table s4 ) . the consensus hiv b ( or hiv c ) sequence was typically observed in carriers of common hla variants ( e.g. , hla a02 , hla a03 , hla b07 , and hla b44 ) and was the sequence combination associated with the minimal generation of presentable epitopes .
in contrast , in most hiv - b- or hiv - c - infected individuals with rare hla variants , we found one or more substitutions at subtype - specific positions that disrupted the hiv consensus sequence .
because of these substitutions , the abundance of the epitopes that these hla variants could potentially present was reduced relative to that found following the processing of the consensus sequences .
these substitution dynamics could deviate within hla suballeles ; for example , in hiv - b - infected patients with hla - b5701 or -b5703 , which present the same three protective epitopes ( iw9 , kf11 and tw10 ) , the selection at subtype - specific positions either concurred ( 1/4 ; st ) or diverged ( 3/4 ; vi , ga , ns ; table s4 ) . divergent selection could result in quite large differences as , e.g. , s was found in over 80% of hiv b sequences from patients with hla - b5701 , but in none with hla - b5703 ( figures 4 and s4 ) . as a result of these differences
, the proteasomal production of iw9 and tw10 will likely be lower in patients with hla b5701 than in those with hla b5703 , and the greater epitope abundance in the latter group may lead to stronger ctl responses and help to explain the higher frequency of associated flanking and intraepitope ctl - escape mutations in hiv from these patients ( table s4 ; ap : hla b5701 , 2% ; hla b5703 , 41% ; tn : hla b5701 , 19% ; hla b5703 , 41% )
. some epitope precursors contained overlapping epitopes that were restricted by more than one hla variant .
one example is the in vitro defined optimal kk10 epitope , which is presented by the protective and rare hla b2705 molecule ( whites , 0%12% ; absent in most african and asian populations ) .
this 10-mer epitope form is either processed in low amounts or not at all , whereas the shorter or longer
epitope forms ( kl8 , kn9 , ki11 , kr13 ) , which are also presented by hla b2705 , are produced in high abundance , primarily as n - terminally extended epitope precursors ( el11 [ kl8 ] , en12 [ kn9 ] , gi15 [ ki11 ] , kr13 ) and are associated with suboptimal ctl responses ( tenzer et al . ,
these epitope precursors contain overlapping epitopes that share the same c terminus and can be presented by other , more common hla class i molecules and may encompass one embedded epitope , py9 , presented by hla - b35 and -b53 ; the only epitope in this study that is surrounded by other epitopes ( figure 5a ; table s1 ) .
these epitope precursors were processed with different efficiencies from hiv b and hiv c , and their abundance was inversely correlated with the combined allelic frequencies of the presenting hla variants ( figures 1c and 3b , mf and cf2 , pins ) .
kk10-containing epitope precursors may be modified by other components of the antigen - processing machinery .
more specifically , the production of many of the optimal epitopes is likely hampered because three proline ( p ) residues upstream of most of these epitopes inhibit erap trimming ( figure 5b , accumulation of kk10-containing trimming product with n - terminal pp ; figure 5c , similar accumulation of an hla b8-restricted gi8-containing trimming product with n - terminal npp ) and because some precursors are cleaved by the cytosolic endopeptidase nardilysin ( nrdc ) ( kessler et al . , 2011 )
nrdc digestion selectively destroys the epitopes presented by the common hla - a24 and -b08 variants ( figure 5a ) , whereas it releases all of the kk10 epitope forms together with the internal py9 epitope ( figure 5d ) .
this py9 production is unlikely to affect ctl responses in most patients because the hiv b and hiv c consensus sequences each contain ctl - escape mutations within py9 that abolish the hla - b35-restricted ctl response in hiv b infection , and the hla - b53-restricted ctl response in hiv c ( matthews et al . , 2012 ,
the presence of these escape mutations at the subtype level may reflect the benefit of a py9-specific ctl response ( matthews et al . , 2012 ) and the opposing frequencies of these hla variants in whites and central and southern africans ( gonzalez - galarza et al . , 2011 ) .
thus , overall intrahost selection can result in immune evasion by favoring hiv sequence combinations that inhibit proteasomal digestion and/or erap trimming and/or exploit nrdc to decrease both overall and specific cd8 epitope presentation and may also select for intraepitope ctl - escape mutations that prevent epitope recognition . when we combined the changes in specific epitope - precursor abundances and the favored hiv selection within patients who shared the presenting hla variant , we found a strong , highly significant host - specific bias toward residues that specifically decrease the yield of epitopes that the host could potentially target ( table s4 , p < 0.0001 [ hiv b ] and p = 0.0005 [ hiv c ] , sign test ) .
potentially unrecognized cd8 epitope promiscuity will add noise to these analyses , but does not compromise them .
this result provides strong evidence that all epitope - presenting hla class i variants exert a selective pressure on these clinically important hiv gag regions . to investigate how hla - driven selection might impact hiv b evolution over time
, we studied longitudinal sequences from five ethnically diverse populations ( figure 6a ) .
the caribbean epidemic is particularly interesting because it is a unique example of the spread of hiv b in populations that are primarily of african ancestry . specifically ,
94/99 hiv b sequences ( 95% ) originated from caribbean countries where > 90% of the population is black ( barbados , haiti , and jamaica ) .
the region currently has the second - highest hiv prevalence rate worldwide , but the start of the epidemic within the region varies greatly ; hiv b appears to have spread from africa to haiti in approximately 1970 ( gilbert et al . , 2007 ) , to jamaica in approximately 1987
( losina et al . , 2008 ) , to barbados in about 1990 ( http://www.unaids.org ) , and to trinidad and tobago between 1993 and 1996 ( gilbert et al . , 2007 ) .
despite the timing of the caribbean epidemic , large numbers of hiv b p24 sequences only became available after 2000 ( http://www.hiv.lanl.gov/content/index ) .
subtype - specific vi and st ( hiv b consensus or wild - type hiv - c - like or mutant ) substitutions accumulated rapidly in hiv b in the caribbean cohort , reaching approximately 75% and 40% , respectively , after 510 years versus approximately 25%35% ( i ) and 10%41% ( t ) , respectively , in the other geographic regions ( figure 6a ) . at time
period 3 , this accumulation was significantly greater than that found in all other cohorts combined for vi ( p < 0.0001 ) but not for st because of a comparable increase in the asian cohort .
moreover , we observed parallel increases in hiv - c - like a ( p = 0.05 ) and s frequencies ( p = 0.05 ) , whereas the hiv b wild - type ed substitution appeared less frequently , although this difference did not reach significance .
these observations collectively provide evidence of distinct hiv b adaptation in the caribbean . to investigate the underlying selective pressures
, we examined the relationship between the frequencies of these hiv - c - like substitutions in hiv - b - infected patients with and without hla variants that restrict epitopes in f1 and f2 ( table s4 ) and the relative frequencies of these hla variants in black caribbeans and whites ( figures 6b and s5 ) ( gonzalez - galarza et al . , 2011 ) . because only hla information from black trinidadians ( bt ) covered all of the necessary hla variants ,
bt were used to represent all the black caribbeans , and all whites were represented by data for us whites ( usw ) .
these analyses revealed which hla variants select for hiv b wild - type amino acids and which select for hiv - c - like amino acids , and if a given hla variant is more , or less , frequent in bt relative to usw ; thus , figures 6b and s5 illustrate the different , and similar , selective forces in the two ethnic groups .
for example , some hla variants associated with selection of s were underrepresented ( hla - a24 , b07 , and b5701 ) in bt when compared to usw ( figure 6b ) . to examine the combined effect of the hla - associated selective forces in each ethnic group
, we summed the weighted allelic frequencies of hla variants selecting for hiv b wild - type or hiv - c - like mutant amino acids at each of the five subtype - specific positions for both bt and usw ( figure 6c ) .
we then examined whether the distribution of the sums was similar at each position within and between the two populations ( i.e. , the distribution of the light and dark orange [ bt ] and the light and dark blue [ usw ] bar heights ) .
although we observed a similar distribution between the sums of hla alleles selecting for either mutant or wild - type amino acids at positions 27 and 41 for both bt and usw , we found a highly significant difference in the distribution pattern between the two ethnic groups ( p
similar strong ethnic differences were observed for the remaining four positions ( p < 0.0001 for each ) combined with distinct distribution patterns within the two populations when considering positions 116 , 120 , and 128 ( p < 0.0001 for each ) .
for all positions , we next investigated whether the ratio of hla variants selecting for mutant over wild - type amino acids was different between bt and usw ( figure 6d ) .
we found highly significant differences in odds ratios between the two ethnic groups ( table s5 ) , which provides evidence of distinct hla - mediated selective pressure on hiv in each population .
our results demonstrate that increases in the i , t , and s hiv - c - like amino acids in hiv - b - infected bt are associated with a higher prevalence ratio of hla variants that select for these amino acids relative to those selecting for the wild - type amino acids v , s , and n compared with usw ( figure 6d ) .
however , this finding did not reflect a higher relative abundance of hla variants that select for hiv - c - like amino acids , but rather , a relative decrease of hla variants that select for wild - type amino acids at these positions in bt relative to usw because the proportion of hla variants selecting for wild - type amino acids in bt relative to usw was 0.65 , 0.81 , and 0.60 for positions 27 , 41 , and 120 , respectively ( figure 6c ; table s5 ) .
similarly , the slight increase in the hiv b wild - type e among bt was associated with a decrease in the frequency of hla variants selecting for the hiv - c - like d substitution , because the proportion for usw was 1.6 times larger than the proportion for bt ( table s5 ) .
the small increase in a over time is an anomaly because the proportion for usw was 1.8 times that of bt , but this increase is likely due to strong competing selective pressures affecting infectivity and natural killer cell recognition , which have distinct effects on hiv b evolution in the two ethnic groups ( fadda et al . , 2011 , martinez - picado et al . , 2006 ) .
when we examined how the usw and bt ratios of hla variants that select for mutant over wild - type amino acids affected substitution patterns at subtype - specific positions , we found a highly significant positive correlation between these hla ratios and the frequency of the hiv - c - like i , t , s , and d substitutions in hiv - b - infected individuals from north america and the caribbean ( figure 6e , p = 0.0001 ) .
position 116 was omitted from this analysis due to the competing selective pressures . because the hla ratio variation affected hiv b evolution at the viral population level in a similar manner at all four subtype - specific positions in both ethnic groups , this ratio is the key driver of hiv adaptation at these subtype - specific motifs .
this correlation directly links the distinct hiv b evolutionary patterns to differences in the hla haplotype distribution in the two populations because the hla data are not linked to the acquisition of the hiv sequences .
because of this relationship , our data provide compelling evidence that the specific amino acid at a given subtype - specific position in hiv b gag affects the processing of all cd8 epitopes in nearby epitope clusters and that viral evolution is influenced by the frequencies of all hla variants that can present cd8 epitopes from these clusters .
together , our data strongly suggest that the combined effect of these hla - driven selective pressures on viral evolution is predictable and that viral founder effects are overlaid by rapid adaptation to local hla population frequencies .
collectively , our data strongly suggest that the hiv b gag - consensus sequence is selected mainly by white hla allelic frequencies and that the ancestral african hla distribution in the caribbean has shaped recent hiv b evolution in this location in a manner similar to the manner in which the hla profile of infected sub - saharan populations may have affected hiv c evolution .
we next studied the influence of hla frequency differences on hiv b evolution across populations worldwide .
the n ( hiv b ) s ( hiv c like ) interchange is particularly informative because s simultaneously decreases b57-tw10 processing and increases b27-kk10 production and because both epitopes are associated with clinically beneficial ctl responses ( table s4 ) .
we correlated hla - b2705 frequencies with the corresponding hiv s and n frequencies and found a strong inverse correlation between the hla b2705 and s hiv frequencies ( p < 0.0001 ) , which was mirrored by a positive correlation between hla - b2705 and n ( p = 0.01 ) ( figure 6e ) .
in contrast , a trend toward a positive correlation was observed for the hla b5701 and s frequencies despite the small size and restricted range of the data set , resulting from the absence of this hla variant in most populations ( n = 8 , p = 0.18 ) .
the rarity of hla b5701 made it difficult to estimate any impact on n frequencies because n is positively selected in most hiv - b - infected individuals ( p = 0.24 ) .
together , the correlation between hla frequencies across populations and the corresponding selection for evasive substitutions in the circulating virus argue strongly for the immune selection of hiv and viral adaptation to antigen - processing preferences .
here , we present an extensive study of hiv evolution and the effect of hiv subtype - specific substitutions on proteasomal processing of more than 50 epitopes presented by approximately 30 hla class i variants in two key clinically relevant hiv b and hiv c gag regions . we have identified a hitherto unrecognized adaptation of hiv gag to the antigen - processing machinery at the viral population level .
this adaptation occurs through substitutions at subtype - specific motifs , and multiple hla variants presenting nearby epitopes all drive selection at the same subtype - specific position .
we provide evidence of a three - way interaction among hiv region , hla frequency , and ethnic group and demonstrate that the proteasomal processing of all cd8 epitope precursors inversely correlates with the hla allelic frequency of the presenting hla variant(s ) in the infected populations . because of this adaptive process , epitopes presented by common hla variants are generated in low amounts , whereas epitopes presented by rare hla variants are made in abundance .
taken together with the reported weak and infrequent ctl responses associated with common hla variants , and the strong and frequent ctl responses associated with rare hla variants in these gag regions ( goulder and walker , 2012 , streeck et al . , 2007 ) , our results support previous findings linking epitope - abundance to the magnitude and frequency of epitope - specific ctl responses ( lazaro et al . , 2009 , ranasinghe et al . , 2011 , schmidt et al . , 2012 , tenzer et al . , 2009 ) .
our data provide clear evidence that all epitope - presenting hla class i variants exert selective pressures on subtype - specific positions in these key hiv gag regions , resulting in population - level immune evasion in both hiv b and hiv c infection .
we demonstrate that this population - level immune evasion reflects the sum of intrapatient adaptations to reduce or obliterate the production of potentially presentable cd8 epitopes .
specifically , we show that the prevailing amino acid in either the hiv b or hiv c consensus sequence is associated with the least production of the epitopes presented by the most common hla variants in both the hiv - b- and hiv - c - infected populations .
in contrast , in patients with relatively rare hla variants , hiv was often found to have nonconsensus amino acids at subtype - specific positions that were associated with a reduction in processing of the epitope presented by these rare hla variants .
thus , the hiv consensus sequences might be perceived as the best hiv sequence for immune evasion in the majority of infected individuals in whom additional individual hiv adaptations to escape the antiviral immune response take place .
these individual adaptations may include intraepitope ctl escape mutations that affect , e.g. , hla binding or tcr recognition and/or further adaptations to limit antigen processing ( goulder and walker , 2012 ) .
notably , these individual adaptations typically differ from the hiv b or hiv c consensus sequence , which suggests that most of these substitutions impose fitness costs on hiv that select for reversion upon transmission to an hla - mismatched recipient .
therefore , this process is very different from the adaptive process we describe here , which helps to create and/or modify hiv subtypes through adaptations to proteasomal preferences at subtype - specific motifs .
this hla - frequency - driven process is so advantageous to viral survival and transmission that it largely shapes the hiv b and hiv c gag consensus sequence .
this process of adaptation to all hla - a , -b , and -c variants may also help to explain the generally better control of hiv replication by hla - b - restricted ctl responses ( kiepiela et al .
hla - b has more alleles ( 2,068 ) than either hla - a ( 1,518 ) or hla - c ( 1,016 ) ( gonzalez - galarza et al . , 2011 ) ; the hla - b locus has the highest occurrence of heterozygosity because of a more even distribution of allele frequencies ( cao et al . , 2001 ) ; and hla - b variants bind an even greater variety of peptides ( marsh et al . , 2000 ) . as a result , the selective pressures on each peptide : hla b combination may be lower , and this will lead to slower adaptation . hence , we hypothesize that hla - b - restricted epitopes are likely to be produced in higher amounts than those restricted by hla - a and hla - c , and this higher epitope abundance is likely to result in a more frequent priming of cd8 t cells and more efficient elimination of infected cells ( faroudi et al . , 2003 ) .
thus , it is likely due to the generally reduced selective pressure by hla - b to limit or obliterate cd8 epitope production that hla - b - restricted ctl responses dominate the ctl response against hiv .
our study of hiv evolution over time in five ethnically diverse populations perhaps most clearly demonstrates the broader importance of the correlation between hla and subtype - specific polymorphisms in hiv gag .
we observed that hiv b in the black caribbean population evolved in a manner resembling that of hiv c in central and southern africa and that this pattern was associated with a relative decrease of hla variants selecting for hiv b consensus amino acids when compared with whites in the us .
moreover , we found evidence of a worldwide adaptation of hiv b to the hla - b2705 allelic frequency in infected populations , providing evidence of adaptation both between and within ethnic groups .
thus , hiv gag subtypes have diversified in part because of their adaptation to the local hla allelic frequency distributions , which contrasts with the current paradigm that hiv subtype diversification is mainly due to random founder effects ( rambaut et al . , 2004 ) .
although founder effects likely also contribute , our data provide strong evidence that founder effects are followed by the rapid adaptation to local hla population frequencies in a predictable manner .
this rapid adaptation may not have been observed previously because of insufficient sequence data from most countries during the start of the epidemic and a lack of data relating to antigen processing of hiv .
our data should be interpreted cautiously when considering other hiv proteins because the extent of hiv adaptation to antigen processing will likely depend on the strength of the selective pressure exerted by ctl responses and because discordant associations exist between viral load and ctl responses toward different hiv proteins ( kiepiela et al . , 2007 ) .
vulnerable regions within other hiv proteins may also demonstrate variable adaptation to the same hla selective pressure , in line with the different hiv b and hiv c cf1 epitope yields .
the gag regions we analyzed in this study are the only regions in the hiv proteome where ctl responses are strongly associated with delayed disease progression ( goulder and walker , 2012 ) , and these regions are therefore potentially important to target through vaccination . our data provide compelling evidence that differences in epitope abundance are part of the reason these two key p24 regions only elicit strong and frequent ctl responses in the minority of patients with a few rare hla - b variants .
although the high evolutionary rate of hiv makes it possible to study the ongoing coevolution of hiv and the host immune response , any pathogen that is largely controlled by ctl responses might similarly adapt to the human antigen - processing machinery to limit epitope production .
differences in hla frequencies between populations are thought to reflect differences in infectious challenges ; however , it is likely that the distinct hla profiles in different populations also impact the evolution of pathogens other than hiv .
possible candidates may include pathogens largely controlled by the ctl response that have long coexisted with humans and have diversified into subgroups in distinct geographic regions such as hepatitis b virus and hepatitis c virus . because hiv-1 selectively adapts to the hla distribution of the infected population , vaccines based on locally prevalent hiv sequences
would be predicted to result in weaker and less frequent cd8 t cell responses than vaccines containing a mosaic of subtypes or ancestral or consensus hiv sequences inferred from patient - derived virus .
however , all these naturally selected hiv sequences will likely result in weak cd8 t cell responses in the majority of vaccinated hiv - uninfected individuals , regardless of how they are chosen and combined , due to similarities among hla frequencies in different ethnic groups ( cao et al . , 2001 ) .
therefore , even the creation of mosaic hiv inserts based on natural hiv sequences is unlikely to substantially increase the processing of epitopes presented by most of the common hla variants . we demonstrate that viral evolution in vivo can alter the processing of all epitopes in overlapping epitope clusters through substitutions at subtype - specific motifs , which suggests that artificial sequence modifications at these positions in vitro could refocus and reverse the poor immunogenicity of hiv proteins .
this vaccine concept would exploit the fact that cd8 t cells have two distinct antigen - load - dependent activation thresholds : one for clonal expansion and one for target cell elimination ( faroudi et al . , 2003 ) .
processing of a modified insert might generate epitopes in high abundance that will elicit strong ctl responses capable of eliminating naturally infected cells that display as little as three peptide : hla complexes on their surface ( purbhoo et al . , 2004 ) .
thus , vaccine efficacy might be improved by unnatural substitutions that increase the processing of subdominant cd8 epitopes presented by common hla variants in vulnerable parts of the virus .
chronically hiv-1-infected patients were recruited from the department of infectious diseases , rigshospitalet , denmark ( table s3 ) .
all patients gave informed consent and were studied according to the regulations of the danish board of medical ethics for human experiments .
peptides were synthesized on an mk - iv peptide synthesizer ( schafer - n ) and purified to > 98% purity using a jupiterproteo c12 column ( phenomenex ) as in tenzer et al .
constitutive proteasomes and immunoproteasomes ( 20s ) were purified from lcl721.174 and lcl721 ebv - transformed human b cell lines as in tenzer et al .
we performed 2 , 4 , and 6 hr digestions with purified constitutive proteasomes and immune proteasomes ( substrate : enzyme ratio:1,000:1 ) ; all peptide digests in one experimental set were performed on the same day .
we used the 4 hr digestion results here to allow detection of all cleavage products while minimizing effects of proteasomal re - entry of already digested peptide as less than 40% of the initial substrate was degraded at this time in all experiments .
we performed capillary liquid chromatography of all peptide digests using a waters nanoacquity uplc system and mass spectrometry analysis as in tenzer et al .
we used the proteinlynx global server version 2.2 for the processing , identification and quantification of the lc - ms data .
we used mass spectrometric fragment intensity as a surrogate marker for quantity because we previously found a highly significant correlation between these two parameters ( tenzer et al . , 2009 ) .
the tap - peptide binding of epitope precursors and optimal epitopes was determined as in tenzer et al .
about 150,000 peripheral blood mononuclear cells ( pbmcs ) per well were stimulated in a 96-well plate with peptides ( 2.5 ng / ml ) , 1 g / ml anti - cd28 , anti - cd49d , and anti - cd107a fitc ( biolegend ) for 6 hr .
after 30 min , 5 g / ml brefeldin a and 1 monensin ( biolegend ) were added .
the positive control contained 2.5 ng / ml pma and 25 ng / ml ionomycin , and the negative cells and cd28/cd49d .
cells were washed and stained with live / dead fixable violet stain ( invitrogen ) , fixed , and permeabilized with bd fix / perm solution ( bd ) and stained with a mix of fluorochrome - conjugated antibodies : cd3 edc , cd8 percp ( bd ) , interleukin ( il)-2 pe , ifn- , pe - cy7 , and tumor necrosis factor ( tnf)- apc ( biolegend ) .
the cell fluorescence intensities were acquired on a cyan adp cytometer ( beckman coulter ) and analyzed with summit software ( dako ) .
we grouped hiv b and hiv c sequences from 1980 to 2009 according to ( 1 ) 5 year time period and ( 2 ) 5 year period and geographic region .
group 3 consisted of all hiv b sequences from 2000 to 2009 grouped according to geographic region , and group 4 contained all sequences from hla - typed hiv - b- or hiv - c - infected persons divided according to hla group ; this group was further divided into groups of patients with or without specific hla variants ( table s4 ) .
we used the sequence tool in the hiv database to randomly select only one sequence from each patient or transmission cluster in groups 13 to avoid skewing .
differences in amino acid frequencies in hiv gag from patients with or without specific hla alleles were estimated using set 4 .
we counted and calculated the amino acid frequencies at each hiv-1 gag p24 position ; each query hiv-1 gag sequence was pairwise aligned to the hxb2 reference strain and mutations were defined as changes relative to this sequence .
the frequency of mutations in the p24 gene was then calculated across each of the data sets 24 .
because we analyzed all hiv sequences in the database , our intraepitope mutation frequencies ( table s4 ) might differ from those reported by smaller cohorts .
hla allelic frequencies were obtained from the allele frequency database ( gonzalez - galarza et al . , 2011 ) and ( assane et al . , 2010 ,
when more than one data set was available from a country , we used weighted mean values unless otherwise specified . for the analyses in figure 1 , we used hla frequencies from the uk ( uk1 = leeds [ n = 5,024 ] , uk2 = sheffield [ n = 4,755 ] ) , the us ( us1 = los angeles , seattle , and detroit [ n = 1,070 ] , us2 = bethesda [ n = 307 ] ) , germany ( n = 11,407 ) , france ( n = 130 ) , south africa ( zulu , n = 100 ; xhosa , n = 50 ) , zambia ( n = 256 ) , zimbabwe ( n = 108 ) , botswana ( n = 161 ) , and mozambique ( n = 250 ) .
we labeled peptide fragments as cd8 epitopes based on the hiv immunology database ( http://www.hiv.lanl.gov/content/immunology ) . because studies disagree as to whether hla - cw03 can bind the vl10 epitope ( zappacosta et al .
, 1997 , zarling and lee , 1998 ) , we did not include a selection pressure from hla - cw03 in our analyses .
we used multilevel modeling to examine the effects of hla frequency , hiv region , and ethnic group on epitope yield .
further analyses were done using binomial generalized linear models ( mccullough and nelder , 1989 ) using the canonical logit link function , fisher s exact test , t tests , and a nonparametric sign test as described in the text and in the supplemental experimental procedures .
these analyses were done using graphpad prism 5 ( graphpad ) , the r statistical package ( version 3.0.0 [ 2013 - 04 - 03 ] ) , microsoft excel 2007 ( microsoft ) , and stat trek ( stattrek.com ) software . a value of p < 0.05 was considered significant .
contributed intellectual input , and all authors commented on the manuscript . h.c . and p.p . | ### Summary:
: summarythe recent hiv-1 vaccine failures highlight the need to better understand virus - host interactions .
one key question is why cd8 + t cell responses to two hiv - gag regions are uniquely associated with delayed disease progression only in patients expressing a few rare hla class i variants when these regions encode epitopes presented by 30 more common hla variants . by combining epitope processing and computational analyses of the two hiv subtypes responsible for 60% of worldwide infections
, we identified a hitherto unrecognized adaptation to the antigen - processing machinery through substitutions at subtype - specific motifs .
multiple hla variants presenting epitopes situated next to a given subtype - specific motif drive selection at this subtype - specific position , and epitope abundances correlate inversely with the hla frequency distribution in affected populations .
this adaptation reflects the sum of intrapatient adaptations , is predictable , facilitates viral subtype diversification , and increases global hiv diversity . because low epitope abundance is associated with infrequent and weak t cell responses , this most likely results in both population - level immune evasion and inadequate responses in most people vaccinated with natural hiv-1 sequence constructs .
our results suggest that artificial sequence modifications at subtype - specific positions in vitro could refocus and reverse the poor immunogenicity of hiv proteins . |
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: a 54-year - old diabetic male presented to our outpatient facility with a history of a calcaneal osteomyelitis after a failed calcaneal open reduction internal fixation and a large post - traumatic septic defect of the achilles tendon area .
his past medical history was only significant for type 2 diabetes mellitus controlled by his oral hypoglycemics .
the patient had sustained the injury and had an urgent surgical intervention 4 weeks prior to his initial visit in our facility .
pedal radiographs and wound cultures were positive for septic necrosis of the wound and also for growth of enterococcus and stenotrophomonas species .
the patient was then admitted for initial surgical debridement and further osseous and soft tissue reconstruction ( fig .
preoperative lateral radiographic ( a ) and clinical views ( b ) of the patient 's initial presentation .
an intraoperative view showing the harvesting of the hybrid flap ( c ) and the blood supply from the distal peroneal perforator ( d ) .
clinical ( e , f ) and radiographic ( g ) views at 3 months follow - up showing the ankle range of motion and no evidence of recurrent bone of soft tissue infection .
our team 's initial plan , after the bone biopsy and intraoperative cultures were obtained , was delayed coverage of the large defect with a reversed sural pedicle flap but this option was not feasible due to an intraoperative finding of a severed distal end of the sural artery .
the sural artery 's function was not intact and was ensured only by the supply from collateral arterial branches .
the reversed flow arch that came from the lateral tarsal and anterior lateral perimalleolar vessels was interrupted .
immediately , the flap was redesigned and laterally transferred as a new flap , additionally based on the distal peroneal perforator .
a partial calcenectomy was also performed , the achilles tendon was retracted proximal in a lateral direction and reattached with two 3.5 mm absorbable bone anchors on the rest of the debrided calcaneus .
the defect was also adequately covered by the additional use of a posterior tibial perforator based flap to cover subsequent marginal skin necrosis of the neighbouring flap area . in order to provide prophylactic sensation over the defect area
, we also performed an end - to - end coaptation of the sural nerve with the lateral plantar nerve .
the donor sites were covered with split thickness skin grafting harvested from his thigh regions .
the patient was kept non - weight bearing for about 3 months after the final reconstruction and was fully ambulating at about 5 months postoperatively .
the flap is outlined proximally at the junction of the two heads of the gastrocnemius muscle , distally 23 cm distal to the perforating branch of the peroneal artery , which is identified on the skin by the depression in the lower part of the tibiofibular space ( or by doppler examination ) , anteriorly just anterior to the lateral malleolus and posteriorly just medial to the presumed course of the sural nerve and vein .
the dissection begins from the anterior border of the skin marking , with an incision along the anterior margin of the flap continuing anteriorly to the lateral malleolus .
the superior extensor retinaculum is incised and the distal peroneal perforator is exposed on the tibiofibular ligament . the anterior margin of the flap is then dissected including the fascia , which is sutured to the overlying skin to prevent sliding of both layers that may damage the perforators . during this dissection ,
as the flap is raised from anterior to posterior , the sural nerve , artery , and the lesser saphenous vein are identified and raised with the fascia underneath .
proximally , with the completion of the skin incision , the sural nerve , the lesser saphenus vein , and the superficial peroneal nerve are divided . in order to provide prophylactic sensation over the defect area , one can perform an end - to - end coaptation of the sural nerve with the lateral plantar or another sensory nerve in the neighbouring area .
distally , the pivot point is 45 cm above the tip of the peroneal malleolus , where the most distal peroneal perforator is usually found .
after rotating the flap ( up to 180 ) to the recipient area , a split - thickness skin graft is used to cover the defect area .
in an effort to cover large soft tissue defects of the heel and perimalleolar regions where there is lack of abundant soft tissue , we have used various kinds of flaps . the hybrid flap
we describe in this article is made up of skin , subcutaneous fat , and fascia of the postero - lateral part of the leg , sural nerve / artery , lesser saphenous vein , and superficial peroneal nerve with its vascular network from the distal peroneal perforator .
this flap contains two sources of blood supply , the retrograde flow of sural artery and the orthodromic flow from the distal peroneal perforator .
the most significant disadvantage of this flap is that the sacrifice of the sural and superficial peroneal nerve results in large anesthetic areas over the lateral and dorsal aspects of the foot .
it is a combined axial ( sural artery ) perforator ( peroneal ) flap that , due to its dimensions , can provide satisfactory coverage of the defect and due to its double blood supply is reliable enough even in cases with serious compromise to the circulation of the major arteries of the lower limb , as long as the peroneal artery is intact .
our utilisation of a hybrid flap to this large traumatic diabetic foot wound was successful after serial debridements and also the utilisation of a posterior tibial perforator based flap to cover the medial region of the foot and ankle .
a combination of a multidisciplinary health care team for the medical and surgical management of osteomyelitis , wound defect , and diabetes mellitus is essential in the overall patient 's successful outcome .
fasciocutaneous flaps for coverage of lower limb defects could be based on more than one vascular pedicles and a hybrid combination may be necessary for larger defects .
the authors have not received any funding or benefits from industry to conduct this study . | ### Summary:
: the axial and perforator vascularised fasciocutaneous flaps are reliable and effective treatment methods for covering lower limb post - traumatic , septic , charcot , and diabetic foot wounds .
the authors describe the unique utilisation of a hybrid flap as an axial - perforator flap combination for the treatment of a traumatic diabetic foot wound . |
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: a 32-year - old male patient was examined for vision loss and the presence of a mass in the left eye in december 2010 .
he had been examined at other hospitals for chronic open - angle glaucoma of the left eye that had persisted since 2006 .
small blisters of the cornea began to appear in october 2007 ; these blisters progressed gradually and eventually invaded the entire cornea . before the appearance of the lesion , no other treatments , such as
laser therapy or phototherapy had been applied , with the exception of eye drops ( alphagan - p ; allergan , irvine , ca , usa ) .
when the patient first visited our clinic , the visual acuity of his left eye was light perception , and the intraocular pressure ( iop ) measured by a tono - pen ( tono - pen aviva , reichert , ny , usa ) was 43 mmhg . upon , slit - lamp examination , a 8.7 7-mm gelatinous mass and blisters covering the entire cornea with new vessels at the 6 o'clock position were observed .
the entire corneal thickness was 1.39 mm , the depth of the degenerated lesion was 0.89 mm , and the residual corneal tissue was 0.50 mm , as measured by anterior optical tomography ( visante optical coherence tomography ; carl zeiss meditec , dublin , ca , usa ) ( fig .
the host cornea was trephinated to a level of 70% to 80% of its thickness using the 8.0-mm hessburg - barron disposable vacuum trephine ( katena instruments , denville , nj , usa ) .
a blunt spatula was used to separate the overlying corneal tissue along the plane of dissection . the anterior lamellar stroma ( about 80% in thickness )
the residual stroma was removed layer - by - layer with repeated dissections until descemet 's membrane was exposed .
the acellular corneal tissue , with a diameter of 8.5 mm , was sutured in place using 32 interrupted stitches of 10 - 0 nylon .
we performed permanent amniotic membrane grafting with a temporary amniotic membrane patch to minimize epithelization delay .
the temporary amniotic membrane and stitches were removed one week after the surgery , and the corneal epithelial defects remained one month after surgery .
iop remained within the normal range , and visual acuity increased to 20 / 200 .
the size of the lesion was 8.7 7 mm , and it consisted of gelatinous white tissue with an irregular surface . under the corneal epithelium ,
myxoid tissue was observed , with a severely vacuolar degenerated stroma beneath the myxoid tissue .
the myxoid tissue was positive on alcian blue staining ( ph 2.5 ) , and a few scattered fibroblasts were observed on hematoxylin and eosin ( h&e ) staining ( figs . 3 , 4 , and 5 ) .
the lesion appeared to be a loose , hypocellular , minimal collagen - depositional , glycosaminoglycan - rich myxoid mass in the subepithelial anterior stroma .
moreover , the central site of the lesion exhibited vacuolar change beneath the myxoid tissue ( fig .
the spindle cells were negative for amyloid ( congo red ) and the vacuoles were negative for chondrocytes ( toluidine blue ) .
myxomas are derived from abnormal fibroblasts that secrete excess mucopolysaccharides instead of producing mature collagen fibers .
corneal myxomas are considered to be a secondary reactive process , and the tumor cells have been suggested to derive from embryonic mesenchymal cells with a multipotential character .
a primary myxoma in the cornea is considered to be rare and a secondary corneal myxoma is a reactive process in someone who has had prior corneal disease or injury inducing chronic corneal edema .
corneal myxomas tend to form anteriorly beneath the epithelium and arise in previously inflamed or injured corneas .
generally , corneal myxomas show spindle - shaped cells within a loose stroma ( h&e ) , and the myxoid stroma stains strongly with alcian blue , indicating high glycosaminoglycan content .
clinically , the differential diagnoses considered were salzmann 's nodular degeneration , allergic hypertrophia , a foreign body reaction , pannus , corneal keloid , amyloid deposition , dermoid tumor , and corneal squamous cell carcinoma .
the patient in this study was being treated with alphagan - p for chronic open - angle glaucoma in a different hospital .
however , there have been no reports that factors , such as glaucoma or glaucomatous agents , induce secondary corneal myxoma . in this case , the myxoma is assumed to be a primary corneal myxoma , because the growing myxoma induced increased iop , and iop returned to the normal range when the myxoma was removed .
this case was similar to a corneal myxoma in the gross and pathological findings on h&e , alcian blue , and masson trichrome staining , but had a lower cell density than other myxomas reported to date .
moreover , the accompanying vacuolar changes in this case were different from those of past myxomas .
contact lens - induced epithelial microcysts or corneal pseudocysts have been previously reported [ 14 - 16 ] , but microcysts were limited in the epithelium and those previous cases differed from this case in the size and number of cysts .
contact lens - induced epithelial microcysts were induced by decreased aerobic metabolic activity due to chronic hypoxia in extended lens wear .
similarly , the vacuolar changes likely resulted from the accumulation of metabolites such as lactic acid in the stroma , because the air supply to the cornea was blocked for a long time by the gelatinous tissue .
however more research is necessary to identify the factors that can induce vacuolar changes in the corneal stroma .
dalk is used to remove pathological corneal stroma from descemet 's membrane and involves transplantation of the stroma from a donor 's cornea .
the advantage of this procedure is that it preserves the recipient 's corneal inner layer and reduces the occurrence of transplant rejection and failure .
recently , dalk using glycerol - preserved corneal tissue was reported to reduce allogeneic immune rejection . in this case , the patient 's descemet 's membrane was intact , but the size of the corneal lesion was 8 mm , which indicated a greater possibility of rejection and involvement of the deep stroma .
we used albumin - preserved acellular corneal tissue from which the cells were removed by gamma irradiation so that the graft was less likely to be rejected .
previous studies have shown that it can also inactivate prions while maintaining the integrity of human albumin , which may be a distinct advantage when compared with other forms of corneal storage available today [ 9,18 - 20 ] .
amniotic membrane is known to decrease surface inflammation and scarring in addition to facilitating epithelialization .
we performed amniotic membrane transplantation for the purpose of improving the microenvironment of limbal epithelial stem cells . in conclusion
, we experienced an 8-mm myxoma in the anterior half of the corneal stroma , accompanied by vacuolation , and we treated it via lamellar keratoplasty with acellular corneal tissue . | ### Summary:
: a myxoma is a benign tumor found in the heart and in various soft tissues ; however , a corneal myxoma is rare .
a mucinous mass of unknown etiology was observed on the left cornea of a 32-year - old male patient .
we performed deep anterior lamellar keratoplasty using acellular corneal tissue and concurrent amniotic membrane transplantation .
hematoxylin and eosin staining revealed vacuolation of the parenchyma and myxoid change in the corneal tissue that occurred in the anterior half of the corneal parenchyma .
we identified a myxoid stroma by alcian blue staining and observed collagen fibers with denatured stroma by masson trichrome staining .
the patient 's visual acuity improved from light perception to 20 / 200 , and the intraocular pressure remained within the normal range for one year after surgery .
the transplanted cornea survived successfully with well - maintained transparency , and recurrence was not observed one year after surgery . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: primary gastrointestinal lymphoma is very rare , constituting only about 1 - 4% of all gastrointestinal malignancies . due to infrequent occurrence
, there are only few reports of colonic malt type lymphoma , and absence of sufficient data makes evaluation and management of these patients challenging .
adult intussusception is uncommon and accounts for 5% of all intussusception and 1% of all bowel obstruction .
mucosa - associated lymphoid tissue ( malt ) and diffuse large b cell lymphomas ( dlbcl ) are the two histologic subtypes most commonly observed .
, we report a case of a malt lymphoma of the colon in a female patient who presented with intussusception .
the therapeutic strategies of this rare entity are not well defined and require further research .
a 35-year - old woman presented with a pain in the right iliac fossa of one month duration with a sudden increase in the severity of the pain . on examination , a tender mass was palpable in the right iliac fossa .
ultrasound and ct scan of the abdomen revealed a ileocolic intussusception with homogenous enhancing mass lesion approximately 5.6 5.3 3.5 cms seen at the lead point .
a fleshy circumscribed polypoid mass was seen at the caecum measuring 5.5 4.5 3.5 cm , with the cut surface showing areas of hemorrhage [ figure 1 ] .
gross specimen : polypoidal mass arising from the ileocecal region microscopy of the lesion with adjacent intestinal mucosa revealed necrosis of the mucosa .
the lamina propria was infiltrated by a monotonous population of lymphoid cells that showed destruction of the glands and were seen extending into the muscularis propria and the serosa .
the cells were small with irregular nuclear membrane , having hyperchromatic nucleus and scant cytoplasm .
the tumor cells were characteristically arranged around the epithelium ( lymphoepithelial lesion ) [ figure 2 ] .
immunohistochemistry was done which showed strong positivity of the tumor cells for cd-20 [ figure 3 ] and negative for cd 10 , thus confirming the diagnosis .
malt lymphoma is defined as an extranodal marginal zone b - cell lymphoma of malt type .
common age of presentation is middle age and older adults with both sexes being equally affected .
the most common site in the large intestine is the caecum , as in our case , and the rectum .
reports of colonic intussusception in adults are less common in literature and are confined to both small and large bowel .
the symptoms of malt lymphoma are nonspecific mimicking colorectal cancer and hence the delay in the diagnosis up to the last stage .
primary intestinal lymphoma most commonly involves the ileocecal region , probably due to the high proportion of lymphoid tissue . because the ileocecal region includes the area from the distal ileum to the cecum
, it is often difficult to designate the ileocecal region as part of the small or large intestine .
thus , the designation for this region differs among studies , as some considered it part of the small or large intestine .
our case was b - cell lymphoma of the ileocecal region which presented as intussusception and had no regional lymph node involvement .
the patient underwent surgery followed by chemotherapy with uneventful course during the three months follow - up period .
immunohistochemical analysis can distinguish the malt lymphoma from other low - grade lymphomas by detecting positivity for superficial immunoglobulins and pan b antigens
cd19 , cd20 , cd79 without expression of cd5 , cd10 , cd23 and cyclin d1 .
colorectal malt lymphomas do not have the same association with h. pylori infection and are treated as a different clinical entity . in the absence of standardized treatment , various treatment methods have been used which include surgery , chemotherapy , radiation and endoscopic resection . as a causative organism
convincing evidence has been established showing the relationship between h.pylori and gastric malt lymphoma , and therefore therapeutic strategy has been altered for the patients with gastric malt lymphoma in the early stages .
in contrast , a therapy for colonic malt lymphoma has not yet been established due to rarity of the disease and late presentation .
conservative treatment is preferred to surgery in the localized gastric lymphomas , the same is not true for intestinal lymphomas because the surgery in combination with chemotherapy has proven superior to any other treatment combination .
thus , because of the divergent therapies reported in the various studies , there are as yet no clear therapeutic guidelines for the treatment of malt lymphoma of the colon
. surgical resection may be effective when a colorectal malt lymphoma does not respond to the eradication therapy or chemotherapy and is localized without dissemination .
the survival of the patients with ileocecal region involvement is better than that of the patients with involvement at other sites , which might be related to the histologic distribution , the proportion of the tumor stage , and the need for surgical resection .
t - cell lymphoma rarely occurs in the ileocecal region and present with complications , such as obstructions requiring immediate surgical intervention .
the treatment for primary malignant lymphomas in general requires a multidisciplinary approach , combining surgery and chemotherapy . in conclusion ,
though definitive treatment has not yet been established , combination of surgery and chemotherapy is thought to be superior to any other treatment combination . | ### Summary:
: mucosa associated lymphoid tissue ( malt ) lymphomas are rare neoplasms .
they are most common in the stomach followed by small intestine and colon .
the symptoms are nonspecific and generally do not present with intussusception . here we report a rare clinical entity in which a 35-year - old female presented to the emergency with severe abdominal pain which was sudden in onset . history revealed that she had been having vague mild abdominal pain for 2 years .
ultrasonography showed ileocolic intussusception with hypoechoic lesion of 54 46 mm seen at the lead point .
emergency laparotomy with the right hemi - colectomy was done .
the specimen was sent for histopathological examination which revealed a diagnosis of malt lymphoma .
awareness of the varied clinical presentation helps in formulating the appropriate therapeutic strategy . |
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: since the mid-1980s , western societies have been witnessing changes in the organization of work , careers , and employment relations .
fordistic to post - fordistic forms of organization ( opitz , 2004 ) or a shift from bureaucratic to post - bureaucratic or entrepreneurial modes of work and career regulation ( du gay , salaman , & rees , 1996 ) .
the effects of socio - cultural and politico - economic transformation processes have been differently evaluated in work , employment and organization studies ( courpasson & reed , 2004 ; mccabe , 2009 ; roper , ganesh , & inkson , 2010 ) , in sociology ( bauman , 2000 ; boltanski & chiapello , 2006 ) and in contemporary management and career studies ( arthur & rousseau , 1996b ; kanter , 1997 ) . concerning the latter , metaphors like the boundaryless ( arthur , 1994 ) , protean ( hall , 1996 ) , post - corporate ( peiperl & baruch , 1997 ) , chronically flexible ( iellatchitch , mayrhofer , & meyer , 2003 ) , or kaleidoscope career ( maniero & sullivan , 2005 ) aim to reflect these developments .
in a nutshell , they tend to emphasize increased individual freedom and autonomies in individuals ' careers , which now allegedly develop beyond the constraints of single organizations ( inkson , 2006 , p. 49 ) which provided traditional careers . due to technological changes , organizational restructuring , layoffs , and demographical developments ,
numerous authors expect radical changes in employment patterns due to these developments ( giesecke & heisig , 2010 , p. 406 ) .
recently , scholars have issued a call to tackle the next stage of the research cycle , i.e. empirical study ( dries & verbruggen , 2012 , p. 269 ) .
one quantifiable indicator for changing career environments is the number of job transitions , which is said to be soaring ( rodrigues & guest , 2010 ) .
but there are substantial doubts concerning the extent of job mobility ( chudzikowski , 2012 ; guest & mckenzie - davey , 1996 ) and some literature even claims that no fundamental change in career behavior and career perceptions has occurred at all ( e. g. , diewald & sill , 2005 ; jacoby , 1999 ; kattenbach , lcke , schlese , & schramm , 2011 ) .
in addition , while the literature on new careers tends to acknowledge contextual and institutional factors , less importance is given to these factors empirically ( mayrhofer , steyrer , & meyer , 2007 ) .
first , do these concepts , which have mainly been developed in the anglo - american context , adequately describe what is happening in different institutional environments such as germany , which is arguably different in terms of dismissal protection , social insurance institutions , education system , and industrial relations ( hall & soskice , 2001 ) ?
second , to what extent is the underlying change assumption in career studies ( mayrhofer , 2012 ) a valid one ?
the paper at hand addresses these questions and analyzes trends of transition probabilities among qualified employees in west germany between 1984 and 2010 .
we concentrate on this group , defined as employees with managerial tasks and or other highly qualified jobs , because it provides a good test bed for the change hypothesis .
highly qualified employees are more difficult to replace , and they enjoy better job conditions ( e.g. in terms of autonomy , power and wage level ) . within the context outlined above
they should perceive fewer economic boundaries and more opportunities for job changes ( powell & maniero , 1999 ; sherer , schwab , & heneman , 1987 ) .
we focus on germany to consider a context with rather rigid institutional structures , characterized by stable welfare institutions and more powerful unions than those in the us ( biemann , fasang , & grunow , 2011 ) .
we will rely on data from west germany only , for the assumed change in the career context beginning in the 1980s , and data from east germany are only available from 1991 on .
our paper contributes to the career literature in three ways : first , by using representative panel data and longitudinal analyses , it seeks to contribute to the reinvigoration of the study of careers ( savickas , 2002 ) .
second , it challenges the change and universality assumption prevalent in much of career research ( chudzikowski , 2012 ; collin , 1998 ; mayrhofer , 2012 ) .
although we acknowledge that change takes place , we argue that the change assumption prevalent in careers research may be exaggerated , and that it can not be generalized across different national contexts .
hence , we do not contest the conceptual quality of mainstream careers theories , most of all the boundaryless career theory , but the universality of their application .
third , and linked with this , the paper points out the relevance of contextual influences exemplified in a highly regulated economy , and it endorses the recently advocated discussion on the impact of institutional factors ( biemann , zacher , & feldman , 2012 ; inkson , gunz , ganesh , & roper , 2012 ) .
two conceptualizations of careers , which reflect the above - mentioned developments and put particular emphasis on the agentic quality of career trajectories , have gained substantial attention in career research and represent the contemporary mainstream : protean careers ( hall , 1996 ; hall & mirvis , 1996 ) , on the one hand , and boundaryless careers ( arthur & rousseau , 1996b ; for a comparison see briscoe , hall , & demuth , 2006 ) on the other .
the former is characterized by careers developing independently of traditional career arrangements ( segers , inceoglu , vloeberghs , bartram , & henderickx , 2008 ) .
it relies on a conception of psychological success resulting from individual career management , as opposed to career planning and development arranged by the organization .
protean careers have been characterized as involving greater mobility , a more holistic life perspective , and a developmental progression ( hall , 1996 ) .
the boundaryless career concept is framed in a similar way . introduced in the mid-1990s and since then increasingly discussed ( see e.g. arthur , khapova , & wilderom , 2005 ; sullivan & arthur , 2006 ) and refined ( arthur , 2008 ; tams & arthur , 2010 ) , the boundaryless career is conceptualized as emancipation from organizations , which used to provide traditional ways of development implying a logic of vertical coordination and long - term commitment .
( arthur & rousseau , 1996a , p. 3 ) and characterized by increased boundary crossing by the career actor ( sullivan , 1999 ) , who may perceive a boundaryless future regardless of structural constraints ( arthur & rousseau , 1996a , p. 5 ) .
according to the latter , the boundaryless career implies not only a mobility in terms of job transitions but also a psychological mobility ( sullivan & arthur , 2006 ; verbruggen , 2012 ) .
however , in the following we focus on physical mobility . both the protean career and the boundaryless career concept share , among other things , the idea of physical mobility across jobs , functions and organizations ( briscoe et al . , 2006 ; sullivan & baruch , 2009 )
hence , when these career concepts increase in importance , one may presume both an overall increase in inter - organizational job transitions , meaning job - to - job changes between organizations ( for the concept of work role transitions see , e.g. nicholson , 1984 ) , and an overall decrease in internal job transitions , broadly defined as any essential change in task and duty within an organization , in particular across hierarchical , functional , and inclusion boundaries ( schein , 1971 ) . for the remainder of this study , we will employ the term external to denote inter - organizational job transitions , and internal to denote intra - organizational job transitions .
despite theoretical claims about the overall increase of job transitions due to boundaryless and protean careers , admittedly the empirical support for such a rise is modest at best ( chudzikowski , 2012 ; pringle & mallon , 2003 ) .
job tenure and turnover have remained stable in several parts of the world ( rodrigues & guest , 2010 : 1168 ) and with each successive generation ( lyons , schweitzer , ng , & kuron , 2012 ) .
recently , rodrigues and guest ( 2010 ) analyzed data from the oecd employment statistics database in order to capture historical trends in job stability for the years 1992 to 2006 .
they find few changes for job tenure and turnover in the us , japan and europe , and there is no increase in job transitions among qualified employees .
their results for germany indicate a moderate increase in job tenure for the german labor market between 2000 and 2006 .
this corresponds to a decreased mobility rate between 1974 and 1994 drawn from an analysis of the gsoep ( winkelmann & zimmermann , 1998 ) .
a more detailed analysis reveals some variations as job tenure declined moderately among men between 15 and 24 , low - tenured workers and men between 55 and 64 .
in addition changes for women older than 25 could be observed , as their tenure increased ( rodrigues & guest , 2010 ) .
likewise , empirical studies show that the number of job transitions ( diewald & sill , 2005 ) and tenure ( auer & cazes , 2000 ) was fairly constant in the 1990s . therefore one should not expect a general linear trend reflecting an increase in boundary crossing probabilities .
this particularly holds true for countries with rather rigid structural boundaries like germany ( biemann et al . , 2011 ) .
data shows that the willingness to change jobs in germany has been rather constant over time ( kattenbach et al . ,
gunz , evans , and jalland ( 2000 , p. 24 ) conclude that the more that boundaries are knocked down , it seems , the more people put up new ones .
rather , we postulate certain inertia in their overall level in germany.hypothesis 1job transition probability among professional and managerial employees in west - germany remains on a stable level between 1984 and 2011 .
job transition probability among professional and managerial employees in west - germany remains on a stable level between 1984 and 2011 .
empirical evidence shows that the business cycle explains much variance in career - related behavior such as job mobility ( cornelien , hbler , & schneck , 2007 ; diebold , neumark , & polsky , 1996 , 1997 ) .
economic factors influence the expansion or downsizing of companies ( ng , sorensen , eby , & feldman , 2007 ) and career patterns ( biemann et al . ,
a longitudinal study conducted in australia revealed that job security was the only organizational factor related to career change ( carless & arnup , 2011 ) .
hence we postulate that oscillations in the level of transitions are influenced by the macroeconomic climate , as measured by gdp.hypothesis 2variations in the business cycle influence yearly oscillations in the level of job transitions among professional and managerial employees in west - germany between 1984 and 2011 .
variations in the business cycle influence yearly oscillations in the level of job transitions among professional and managerial employees in west - germany between 1984 and 2011 .
career stage and age are a well - known factor when looking at various career outcomes .
the career literature offers many age - related conceptualizations of careers with varying numbers of stages and cut - off points but very similar patterns for career developments ( e.g. gould , 1978 ; levinson , 1978 , 1996 ; munley , 1977 ; vaillant , 2002 ) .
different levels of job transitions are reported for the single career - stages , e.g. with a peak in the starting and mid - career phase and a decrease with further career progress ( e.g. lyons et al . , 2012 , p.349 ) .
the frequency of external job mobility has a significant positive effect on salary earned in the us and in hong kong ( lam , ng , & feldman , 2012 ) , although this effect is moderated by the individual 's career stage : the positive effects are stronger for early - career workers than for mid- and late - career workers . more general and detached from individual career progress , age has been recognized as a fundamental explanatory factor for turnover decisions ( e.g. mowday , porter , & steery , 1982 ; sullivan & crocitto , 2008 ) .
empirical work on job transitions shows that younger managers are more mobile than older managers ( biemann et al .
, 2012 ; groot & verberne , 1997 ; ng & feldman , 2009 ; nicholson & west , 1988 ; o'brien , 2007 ) . in accordance with this repeatedly confirmed finding , we hypothesize that the level of job transitions decreases with age.hypothesis 3athe probability of job transitions among professional and managerial employees in west - germany decreases with age between 1984 and 2011 .
the probability of job transitions among professional and managerial employees in west - germany decreases with age between 1984 and 2011 .
there are contextual developments with the potential of challenging this relationship between age and job transitions , however .
first , with the current increase in the mean and average ages of people in developed countries , they tend to stay in the workforce longer ( feldman , 2007 ) .
second , as the organizational career jungle - gym ( gunz , 1988 ) is becoming increasingly flatter , longer job duration for late career stages bears potential consequences for early career stages as well , decreasing available space .
hence , the literature might suggest that the age effect outlined in hypothesis 3a declines over time .
as far as the first objection is concerned , german labor law managing entitlement to retire is rather rigid , and has changed only recently in 2012 , allowing for more flexibility .
it offers relatively high security for employees , such as enhanced dismissal protection with progressing seniority and at least up to now a comparably well - equipped public and occupational pension scheme .
second , the early retirement rate has been fairly constant over the years ( oecd , 2003 , 2011 ) .
the germans like many populations in western europe such as the austrian , italian , or french seem to regard retirement as their sacred right which they intend to realize as soon as possible ( vance & paik , 2011 ) .
third , the compensation plans based on seniority make people in later career stages more expensive for organizations .
this leads to special incentive schemes for realizing early retirement as well ( lcke , kattenbach , & schramm , 2013 ) .
as far as the second objection is concerned , one has to remember that the baby boomer generation ( defined as the post - world war ii cohort born between 1946 and 1964 ) responsible for this potential problem ( collin , 2003 ) , has begun to retire in larger numbers only at the end of the first decade of the millennium .
hence , problems of replacement in the labor market will only be likely from then on , and related effects have not affected our sample .
as a result , we postulate that for germany the decreasing probability of job transition with increasing age does not change significantly over time.hypothesis 3bthe age effect among professional and managerial employees in west - germany remains constant between 1984 and 2010 .
the age effect among professional and managerial employees in west - germany remains constant between 1984 and 2010 .
our study uses data of the german socio - economic panel ( gsoep ) , 2012 release ( wagner , frick , & schupp , 2007 ) .
the analysis focuses on west germany to ensure continuity of the societal framework across the whole period from 1984 to 2010 .
the gsoep is a longitudinal household - based panel survey which has been carried out every year since 1984 . as a representative set of individual data in germany ,
the gsoep provides a platform for examining not only objective socio - demographic and economic measures but also information concerning personality and the subjective perceptions of working conditions .
the gsoep data have been widely used to investigate the individual effects of job instability ( e.g. bethge , radoschewski , & mueller - fahrnow , 2008 ; boerner & schramm , 1998 ; clark , knabe , & rtzel , 2008 ; lurweg , 2010 ; schramm , 1992 ) .
they include downward mobility ( pollmann - schult , 2006 ) , the effect of economic growth and the unemployment rate on job transitions ( cornelien et al . , 2007 ) or changes in career patterns ( biemann et al . , 2012 )
even changes in internal ( diewald & sill , 2005 ) and external job transitions have been investigated ( giesecke & heisig , 2010 ) , but none of the mentioned studies has focused either on the boundaryless career concept or on the specific group of qualified employees to which the predictions of the boundaryless career should especially apply . furthermore with an observation period which grows year by year , the gsoep dataset has become more appropriate to analyze long - term trends as implied by the emergence of boundaryless careers .
participants in the gsoep are asked on a yearly basis whether they have changed their job position during the last year .
since this information refers to the previous year , we have predated the information on transitions to the referred year . the initial question is followed by several items on the nature of and reason for the job change .
we have derived two dichotomous variables indicating internal job transitions ( i have changed positions within the same company ) and external ones ( i have started a new position with a different employer ) .
we have used the regional gross domestic product growth rate in real terms for west germany .
the data from 1983 to 1991 is drawn from the federal ministry of labor and social affairs ( bmas ) ; from 1992 to 2010 , we used the data from the federal statistical office and statistical offices of the states ( statistische mter des bundes und der lnder ) .
( 2007 ) have shown , the pattern of seasonal changes in the gdp has been repeated over the years .
thus , for considering a trend over several years , seasonal changes can be disregarded , or more precisely , subsumed under their respective years .
it is reasonable that the effect of economic developments on the labor market has a certain delay . to cover the direct as well as the lagged economic effect , we have included a gdp variable for the year of job transition and a lagged gdp variable indicating the economic growth in the year before the transition took place .
age and sex category . in postulating a major effect of age on the occurrence of job transitions ,
we have generated an age variable referring to the reported year ( previous to the survey year ) .
age has also been used as a demarcation variable for the sample of qualified employees .
only employees aged 20 to 63 in the reported year have been included in our analyses .
the lower end is to exclude people without sufficient vocational experience and/or education to reasonably belong to the group in question .
the upper end has been chosen due to the retirement age in real terms in germany .
although the legal retirement age is 65 for both sexes , the effective average age for retirement is 61.8 for men , and 60.5 for women ( statista , 2013 ) . for multi - level analyses the year dates and
the age variable have been centralized to the lower bounds of 1984 and 20 years respectively .
regression coefficients can therefore be interpreted as an increase in the percentage probability with each additional year in the course of time and in one 's working life respectively .
gdp regression coefficients can be interpreted as an increase in the percentage probability with each percentage point of economic growth .
sex category is operationalized as a dichotomous variable with 0 male and 1 female. sample .
respondents who have reached a managerial or professional position once remain in this status group on the average for a period of m=4.8years ( sd = 4.85 ) .
the size of the group of respondents for each year ranges from a minimum n1987 = 396 up to n2002 = 2219 .
table 1 provides an overview on sample size , gender and job transition rates summarized for 5-year periods ( with the final period , however , being six years in duration ) .
the second column nacc indicates the accumulated number of responses for each period whereas nwght / year estimates the average yearly population size for each period .
sample descriptives are weighted by a grossing - up factor to extrapolate results from the gsoep sample and project them onto the population of all qualified employees in west germany .
when exploring structural changes in career paths due to a demographic change , the data reveal only little impact on the group of qualified employees . within two decades
the proportion of qualified female employees in the predominantly male group has risen by 50% from about one fifth in the late 80s to one third in recent years .
compared to the much discussed but still weak demographic change , this gender - related change in workforce composition is clearly more striking .
analysis procedure . to examine the development of job transitions over time and under the impact of the economic cycle ( gdp ) , age and gender ,
for dichotomous dependent variables like the occurrence of a job transition , the multilevel linear probability model ( lpm ) is an appropriate analytical tool , although there are two shortcomings .
first , predicted probabilities are not restricted to the range of 0 to 1 ; higher and negative outcomes are possible . due to limited variance of the independent measures ( e.g. gdp and sex )
the second often mentioned shortcoming is that marginal probabilities are constant in lpm and therefore do not depend on the values of the explanatory variables .
however , for the independent variables used in our models , we precisely assume constant marginal probabilities , e.g. with age , gdp or the course of time .
additionally , the coefficients of a probit model would be much more difficult to interpret for continuous regressors ( wooldridge , 2009 : 250 ) . for job transitions in general , and for internal and external transitions
in particular , we have carried out multilevel linear probability models to predict the impact of the independent variables on the probability that a job transition takes place ( wooldridge , 2009 ) .
the individual characteristics , age and sex , are considered as respondent - related level 2 variables whereas the course of time and the economic cycle ( gdp ) on a yearly basis represent macro - characteristics of the economic and societal situation ( level 1 ) .
although age is perfectly correlated with the course of time on an individual level , it shows like the other regressors no multicollinearity ( see vif values in table 2 ) , since individuals start survey participation at different points in time and at different ages .
testing structural changes of the age - effect over time , as well as controlling for a changed impact of sex , we have included cross - level interaction terms ( year age and year sex ) in the models . to find the most appropriate model to fit the data we have compared five different models using likelihood ratio ( lr ) tests .
the five models are a multilevel lpm null model without independent variables , a simple ols regression null model as an alternative analysis model and three nested linear probability models ( lpms ) successively including level 1 and level 2 variables as well as interaction terms of age and sex with time .
a significant lr test indicates that the nested models are more appropriate than the less detailed null models .
lr tests reveal that a multilevel probability model using the panel structure of the gsoep is more appropriate to explain variance in the probability of global job transitions , internal transitions and external transitions than simple ols regression ( p < .001 for each of the three dependent variables ) and the inclusion of both level 1 and level 2 variables outperform the more restricted models .
table 3 summarizes the lr tests indicating that the lpm models including variables from both levels and the cross - level interaction term are superior to their nested models in explaining general job transitions and internal transitions . only for external transitions
the inclusion of cross - level interaction does not improve the model fit indicating that the interaction between time and age can be ignored due to insignificance .
the best fitted models have been chosen to test hypotheses 1 to 3a and 3b for job transitions in general as well as for internal and external transitions .
the grand mean of job transition probability for qualified employees in west germany during the observed period is about m = 12.61% per year , i.e. they change jobs every 8.56 years on the average .
this frequency is only slightly higher than for lower qualified white - collar workers in west germany ( 8.32 years , p < .001 ) but substantially higher than for qualified employees in east germany between 1990 and 2010 ( 9.57 years ) .
while female internal transition rates have declined from 8.55% in the 1980s to 4.64% nowadays , which is quite similar to male transition rates ( 3.52% ) , external transition rates do not show a linear but rather a volatile development over time ranging from 8.57 to 13.25% whereas male rates remain at a stable level between 7.38 and 8.59% .
note that the occurrence of internal job transitions is remarkably low in comparison to external job transitions ( table 1 ) .
the best - fitted models to explain the probability of general job transitions , internal and external transitions are shown in table 4 .
we will first present the general model findings ( jj - trans , left column ) before we go more into detail by separating the internal ( int - trans , middle column ) and external transitions ( ext - trans , right column ) .
the most striking finding is that there is a negative tendency , albeit a slight one , in the frequency of job transitions over time ( b = .0017 ; p < .05 ) .
therefore , our hypothesis 1 postulating no change at all has to be rejected . supporting hypothesis 2
, variations in the business cycle have a quite pronounced positive influence on the occurrence of job transitions .
the gdp in the year of transition ( b = .0033 ; p <
.001 ) as well as the lagged gdp of the previous year ( b = .0035 ; p < .001 ) provide explanatory value for the probability of job transitions . also the age of the qualified employees shows a significant impact on the probability of job transitions .
moreover , the negative age effect as assumed by hypothesis 3a is by far the strongest effect tested in our model ( b = .0086 ; p < .001 ) . put differently ,
the probability of a job transition is reduced by 8.6 percentage points every 10 years of one 's working life . the assertion in hypothesis 3b that this age effect is stable over time
the interaction term of age and the course of time reveal a significant cross - level moderating effect of time and age ( b = .0001 ; p < .05 ) meaning a weakened age effect over the years .
controlling for sex , the data show a higher frequency of job transitions for qualified female employees ( 1.58 percentage points ) .
1 breaks the job transitions down into internal and external ones . besides the volatile pattern of job transition rates over the years , different developments for internal and external transitions are striking .
the differentiation uncovers a distinct negative trend over time for internal transitions while the frequency of external transitions has only slightly increased .
this main result contradicts the widespread implicit assumption of increasing dynamics in qualified professional and managerial careers , but it confirms a development towards more inter - organizational movements and shrinking internal labor markets .
contrary to the impact of time , the same and the previous year 's economic cycles do not affect internal , but only external transitions . independently of macro - effects , age remains a major regressor .
for both internal and external transitions , this negative effect is highly significant , but for external transitions the effect size ( b = .0057 ; p < .001 ) is almost double as high as for internal transitions ( b = .0029 ; p <
by contrast , the moderator effect of time on age as found in the general model , can clearly be assigned to internal job transitions ( b = .00005 ; p <
.01 ) whereas the interaction term failed to improve the lpm model for external transitions ( table 3 ) .
( 1 ) do concepts like the boundaryless career , which have mainly been developed in the anglo - american context , adequately describe what is happening in different institutional environments such as germany ?
the answer to the former is most probably no , and to the latter only to a certain extent . as far as the universality of increasing change and job transitions is concerned
, our results suggest that the overall level of job transitions among professional and managerial employees in germany has in fact slightly declined between 1984 and 2011 .
this is the result of the interplay of internal transitions which have clearly decreased and slightly increasing external transitions . when taken in isolation , both dimensions of physical mobility point in a direction congruent with this mainstream careers theory , but their interplay suggests quite the opposite .
the decrease in internal job transitions indicates shrinking internal , intra - organizational labor markets .
these markets used to be one of the central institutions for maintaining employability in systems owing to a logic of vertical coordination ( doeringer & piore , 1985 ) .
downsizing , delayering and vertical disintegration have truncated the room for internal transitions , especially for highly qualified professionals ( cp .
morris & farrell , 2007 ) . in a number of countries such as germany ( neus & walter , 2009 ) or australia , new zealand and south africa ( littler , wiesner , & dunford , 2003 ) fewer job opportunities are offered by the companies .
delayering also provides an explanation for the perceived cross - level moderator effect of time . especially middle management with an overrepresentation of younger and middle - aged qualified employees is affected by delayering while elderly professionals are less affected ( littler et al . , 2003 ; see also faust , jauch , & notz , 2000 ) .
in addition , employees of big companies are more affected by this development , whereas industry shows a negligible influence over time ( giesecke & heisig , 2010 ) .
indeed , recent findings from the german language area point towards a revival of , or even a sustained attractiveness of more traditional career aspirations . for example , a longitudinal , multi - cohort study of business school graduates and their career aspirations in austria indicates that more recent career cohorts show a higher preference for a company world career field ( mayrhofer et al . , 2011b ) , characterized by tight coupling and stable configuration ( iellatchitch et al . ,
, an analysis of career expectations in germany between 1999 and 2009 shows no tendency towards an increased preference for post - organizational career arrangements ( kattenbach et al . , 2011 ) .
arguably , contextual developments like the russia crisis in 1998 or the so - called financial crisis in 2009 have left their footprint on the career motivations of contemporary individuals . both aspirations for as well as actual realizations of external transitions
are highest in times of economic upturns , since the number of attractive job offers increases and the logic of chains of vacancy leads to a leverage effect ( stuck , 2006 ) . beyond the lack of increase in the number of job transitions in germany , the importance of the economic cycle for explaining variations in the level of job transitions
( 2012 ) that factors like industry size , organizational size , or unemployment rates serve as important variables in the career construction process ( see also savickas , 2005 ) .
another study with a german sample , based on retrospective information on employment histories , found a significant impact of economic growth on inter - organizational mobility as well ( biemann et al . , 2011 ) .
this fosters the call for comparative career studies with an international or even an inter - continental perspective . comparing europe and north america
, one should note that the respective business cycles themselves follow different cycle dynamics ( e.g. stock & watson , 2005 ) .
furthermore the link between the business cycle and labor market may differ in germany and the us , as labor law in germany attenuates the business cycle effects , for example by strong protection of employee rights in the case of losing one 's job . as a caveat , an alternative explanation for the general decline in internal changes can be a changed understanding of job transitions themselves . while we have conceptualized an internal job change as any essential change in task or duty
, respondents may interpret an internal job change as a clear move onto a different position with a different job title , even if a promotion is not implied . the term
inkson ( 1995 ) noted that the number of professionals who declared a change in duties steadily increased from 2.8% in 1980 to 8% in 1992 .
this could be an explanation for not interpreting job transitions as an internal transition nowadays , because the transition is not regarded as a change in jobs , but rather a change in tasks .
respondents are asked whether they experienced a job change in the last year . only in the case of confirmation
the questions and their order thus impede the respondents from considering whether changes in their duties are actually a change in their job .
hence , we assume that the low number of internal changes found in the gsoep may under - represent intra - organizational mobility .
this is supported by findings which report higher internal change - rates ( e.g. 7.2% between 1987 and 1996 in a case study of a dutch organization , see dohmen , kriechel , & pfann , 2004 ; around 9% in a study among professionals in the uk between 1980 and 1992 , see inkson , 1995 ) .
even after taking this caveat into account , there is no reason to suppose that there was a strong increase in the number of overall job transitions during the time span analyzed .
although this number indicates less physical job mobility than in the usa or japan ( arthur & rousseau , 1996a ) , it still illustrates the importance of an inter - organizational career perspective as fostered by the boundaryless career concept instead of focusing on organizational careers .
however , as far as the underlying basic change assumption is concerned , we concede that although change takes place , its extent is overestimated .
it is a common theme in social science to disagree about the extent to which things change and the volatility present times induce ( eccles & nohria , 1992 , p. 25 ) and to stress that we tend to see
the present always [ as ] an exciting , challenging time to be contrasted with a stable past
( collin , 1998 , p. 412 ) . indeed , germany 's past is in certain aspects different from the present , illustrated e.g. by the increasing number of women entering the labor market ( oecd , 2012 ) , or by a greater variety of employment forms and the rise in so - called atypical relations ( brehmer & seifert , 2008 ) .
for example , results from comparative hrm show that variables like the size of the hr - department relative to the number of employees or the organizational investment in training and development remain stable despite the widespread popular claims to the contrary ( mayrhofer , brewster , morley , & ledolter , 2011 ) .
again , our empirical paper does not conceptually criticize the boundaryless and protean career ideas ( to this end , see arnold & cohen , 2008 ; inkson et al . , 2012 ) , but argues for a contextualization thereof ( mayrhofer & schneidhofer , 2009 ; mayrhofer et al . , 2007 ) .
such a contextualization encompasses not only countries ( briscoe , hall , & mayrhofer , 2012b ) , but also professions , as e.g. knowledge workers ( colic - peisker , 2010 ) , academics ( dany , louvel , & valette , 2011 ) or workers in the creative industries ( mckinlay & smith , 2009 ) experience different developments even in rather regulated contexts .
future research should , therefore , focus on a more elaborate comparison of the interplay between country , institutional and cultural context , industry , and organizational and individual characteristics to draw a more nuanced picture of developments in career patterns over time .
also , further analyses of the explanatory power of economic growth for different age groups are needed .
preliminary analyses have shown that the gdp has a strong effect on job mobility for young and advanced qualified employees , but not for seniors ( schneidhofer et al . , 2012 ) .
moreover , an expansion of the research design to various groups of employees arranged according to e.g. sectors , professions , and work attitudes could provide interesting insights on the scope of our results and reveal additional influential aspects on the development of careers .
our results provide support for a critical view on the largely unquestioned acceptance of the assertion that there are increasingly dynamic careers with more frequent job transitions among qualified employees .
this does not necessarily challenge the concepts linked with it or the new deal at work ( cappelli , 1999 ) . yet , it cautions researchers neither to generalize too much from observations of specific groups of individuals in specific regions of the world for whom new careers may be a reality , nor to universalize the concept by applying it to diverse cultural and institutional environments . furthermore
, our findings support a call for more comparative research in careers ( as realized e.g. in briscoe , hall , & mayrhofer , 2012a ) including qualitative , or even relational ( see zbilgin , 2006 ) approaches . | ### Summary:
: by examining trends in intra - organizational and inter - organizational job transition probabilities among professional and managerial employees in germany , we test the applicability of mainstream career theory to a specific context and challenge its implied change assumption . drawing on data from the german socio - economic panel ( gsoep ) ,
we apply linear probability models to show the influence of time , economic cycle and age on the probability of job transitions between 1984 and 2010 .
results indicate a slight negative trend in the frequency of job transitions during the analyzed time span , owing to a pronounced decrease in intra - organizational transitions , which is only partly offset by a comparatively weaker positive trend towards increased inter - organizational transitions .
the latter is strongly influenced by fluctuations in the economic cycle . finally , the probability of job transitions keeps declining steadily through the course of one 's working life .
in contrast to inter - organizational transitions , however , this age effect for intra - organizational transitions has decreased over time . |
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: many attractive smiles are marred by some discoloration or stain , either on an individual tooth or on all teeth .
isolated yellow , brown , or white hypoplastic areas on an otherwise normal enamel surface are common .
such defects usually occur due to dental fluorosis amongst patients residing in areas with high fluoride content in drinking water .
dental fluorosis has been categorized under various grades as follows : grade 0 : normal , translucent , smooth , and glossy teeth ; grade i : white opacities , faint yellow line ; grade ii : changes as in grade i and brown stains ; grade iii : brown line , pitting , and chipped off edges ; grade iv : brown , black and/or loss of teeth .
various methods have been suggested to remove or mask discoloration such as vital or nonvital bleaching , microabrasion , macroabrasion , and direct or indirect veneering procedure .
isolated brown or white defects of less than few tenths of a millimeter depth can be successfully treated with microabrasion .
however , a combination of various techniques such as microabrasion / macroabrasion along with bleaching or full or partial veneering are available to effectively mask deeper defects .
originally , the use of 18% hydrochloric acid was recommended to remove superficial fluorosis stains .
later on , the procedure was modified to incorporate the use of pumice and hydrochloric acid paste and was termed microabrasion .
croll further modified the technique , reducing the concentration of acid and increasing the abrasiveness of the paste using silicon carbide particles instead of pumice .
currently , microabrasion is performed by applying abrasive slurry of silicon carbide and hydrochloric acid using a manual or handpiecedriven rubbing action .
the depth of the discoloration can not be known until attempts are made to remove it .
abrasive disks are used for gross contouring , finishing and polishing of ceramic and resin materials
. super snap ( shofu inc . , japan ) is one such system that is used at low speed ( 1000015000 rpm ) .
this system provides high gloss finish when used sequentially from coarse to ultra fine grit .
these abrasive discs along with hydrochloric acid may be utilized during microabrasion to reduce the chair side time and to improve efficacy .
the mechanism of color improvement appears to be the removal of discolored surface enamel and the creation of a highly reflective enamel surface that may mask any remaining discoloration .
the combined benefits of enamel microabrasion followed by home tooth whitening using carbamide eroxide have been reported in case studies.[911 ] in vitro studies favor the application of neutral sodium fluoride after microabrasion treatment to create enamel that is significantly more resistant to demineralization than untreated enamel .
this report presents a modified microabrasion technique followed by in office bleaching that resulted in a significant reduction of the discoloration .
a 21-year - old female patient reported to the department of conservative dentistry and endodontics with the complaint of discoloration in upper front teeth [ figure 1 ] .
history of the patient revealed the presence of yellowish brown and white patches on teeth since childhood .
clinical examination showed the presence of dark yellow patches in maxillary central incisors and white patches on the facial surface of all teeth .
careful exploration of teeth revealed intact and smooth enamel surfaces . several treatment options suggested to the patient were microabrasion , microabrasion along with bleaching , and direct or indirect veneers .
after discussion , it was agreed to use enamel microabrasion followed by bleaching to improve the appearance of her teeth .
the maxillary canines and incisors to be treated were first cleaned with pumice and water slurry .
petroleum jelly was applied around the cervical portion of the teeth to prevent leakage of the hydrochloric acid or damage to the gingiva .
freshly prepared solution of 11% hydrochloric acid was applied using cotton pellet on the discolored area followed by application of coarse composite contouring discs ( super snap , shofu inc .
, japan ) at low speed for 10 seconds per tooth [ figure 2 ] .
same procedure was repeated 3 times at the same visit , which resulted in lightening of the dark areas to a great extent [ figure 3 ] .
white spots were still evident on the labial surfaces of teeth . thereafter , the remaining acid was rinsed from the teeth by use of gentle air water pressure and a high - volume aspirator .
all teeth were finished using fine and extra fine grit abrasive discs ( super snap ) . after finishing ,
the bleaching agent ( xx - white , dentn co. , france ) was applied over the labial surfaces of isolated teeth , followed by light activation using a bleaching light ( flexi light whitening system , dentn co. , france ) for 4 minutes [ figure 4 ] .
the bleaching agent was removed by means of moist cotton followed by rinsing with air water spray .
all the treated teeth were polished using fine polisher ( compo site , shofu inc , japan ) to obtain high luster .
high gloss finish obtained after fine polishing , camouflaged white spots as well as remaining dark areas on the enamel surface [ figure 5 ] .
the patient was informed regarding the likelihood of developing dentinal hypersensitivity , which would subside in a few days .
the patient was prescribed the calcium sodium phosphosilicate - containing desensitizing tooth paste ( vantej , dr .
reddy 's laboratories ltd . , india ) for 3 weeks and then discharged . at 1 month
follow - up , the results were stable and the patient did not complain of any symptoms related to dentinal hypersensitivity [ figure 6 ] .
preoperative view showing yellowish discoloration on labial aspect of both central incisors and chalky labial surface of all teeth application of acid via cotton pellet followed by use of coarse grit abrasive discs for 10 seconds at low speed under rubber dam isolation note the color change immediately after completion of microabrasion in office power bleaching procedure carried immediately after microabrasion completion of finishing and polishing procedure .
note the high luster obtained producing camouflage effect and masking the white chalky patches one month follow - up visit showing constancy of esthetics achieved after treatment
microabrasion is a noninvasive , conservative , and economical approach to partially or completely remove superficial enamel discoloration .
lower cost of this technique makes it a viable treatment alternative in rural / semi urban dental practice .
microabrasion technique has been modified several times to enhance the esthetic results as well as simplify the treatment procedure .
discolored teeth without loss of surface integrity of enamel are ideally suited for microabrasion treatment . however ,
if discoloration is accompanied with pitting of the surface as in grade iii or grade iv fluorosis , clinicians can utilize a combination of microabrasion / bleaching followed by direct or indirect veneering procedures .
it is prudent to carry out microabrasion and in office bleaching under strict isolation using rubber dam as the acid and 35% hydrogen peroxide used in the procedures may damage the adjacent soft tissues .
application of petroleum jelly over the gingival tissue prior to placement of rubber dam provides added protection from the acid .
also , the use of protective eye wear during the procedure by the patient as well as operator is mandatory .
long term effectiveness of microabrasion is clinically proven in several studies and case reports with no or minimal intra - operative and post - operative discomfort such as dentinal hypersensitivity.[1315 ] not only does microabrasion mask and remove stained tooth structure , thus improving tooth color , but the surface layer created during treatment is a highly polished , densely compacted , mineralized structure . the technique is believed to modify the optical properties of enamel .
abrasion of enamel prisms combined with acid erosion results in the development of a densely compacted prism - free layer on the enamel surface .
in addition , subsurface stains may be camouflaged by the optical properties of the newly microabraded surface .
the original microabrasion technique utilized the slurry of 11% hydrochloric acid and silicon carbide using a manual or handpiece - driven rubbing action . in the present case ,
technique was modified in an attempt to reduce chair side time and enhance effectiveness as well as convenience . instead of slurry of abrasive and acid ,
the acid was applied directly on the tooth surface and the abrasive effect was achieved by the use of coarse composite contouring discs ( super snap ) .
thus , the abrasive action was limited only to the area of contact of the disc , thereby , avoiding unnecessary loss of enamel surface . the combined regimen ( microabrasion and bleaching )
is most effective in patients who have prominent white areas on teeth that are yellowish or that have darkened with age . in office bleaching
was preferred in this case over home bleaching regimen because it is quick and the dentist is in total control of the treatment .
several bleaching agents are available in the market such as hydrogen peroxide and carbamide peroxide in various concentrations . in general , the efficacy of hydrogen peroxide containing products are approximately the same when compared with carbamide peroxide containing products with equivalent or similar hydrogen peroxide content and delivered using similar format and formulations .
peroxide and light treatment significantly lighten the color of teeth to a greater extent than does peroxide or light alone , with a low and transient incidence of tooth sensitivity .
use of casein phosphopeptide - amorphous calcium phosphate containing tooth paste after microabrasion have been found to significantly reduce the enamel surface roughness thus , minimizing the risk of developing smooth surface caries .
bioactive glasses like calcium sodium phosphosilicate when in contact with saliva , rapidly release sodium , calcium , and phosphorous ions into the saliva , which are then available for the remineralization of the tooth surface and result in the formation of hydroxyl carbonate apatite . to conclude , the case presented supports a feasible and conservative technique to manage enamel discoloration . | ### Summary:
: esthetics is a primary concern amongst young patients and represents a challenge to the dentist .
discolored teeth are frequently seen in the general population .
several techniques have been devised to minimize or completely eliminate tooth discoloration .
this case report highlights the successful management of enamel discoloration via modified microabrasion technique followed by in office bleaching . |
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: the neuropathological hallmark of parkinson 's disease ( pd ) is the progressive degeneration of dopaminergic ( da ) neurons in the substantia nigra pars compacta ( snpc ) , affecting about 12% of the human population older than 65 years .
it is characterized by the clinical symptoms of resting tremor , muscular rigidity , postural instability , a positive response to the administration of l - dopa , and the presence of cytoplasmic inclusions in postmortem brains , lewy bodies . despite its mostly sporadic onset and a high discordance rate in monozygotic twins ,
several human linkage studies had been initiated to determine susceptibility genes for this disease . in the online mendelian inheritance in man ( omim ) database , 13 pd loci
have been recorded : park1 , park2 , park3 , park4 , park5 , park6 , park7 , park8 , park9 , park10 , park11 , park12 , and park13 .
furthermore , genome - wide analyses of multiplex pd families provided evidence for linkage to regions on different chromosomes . the park loci are sometimes larger than 10 mb and can contain hundreds of genes . in case of the genome - wide linkage studies for a complex , multifactorial disease such as pd , the regions with high lod scores are rarely smaller than 20 cm .
the differences among independent studies and the size of the suggested susceptibility regions make the searches for the underlying mutations irremediably a time - consuming process . for several park loci ,
mutations in -synuclein ( park1 and park4 ) , dj-1 ( park7 ) , parkin ( park2 ) , pink1 ( pten - induced putative kinase ) ( park6 ) , lrrk2 ( leucine - rich repeat kinase 2 ) ( park8 ) , uchl1 ( ubiquitin carboxy - terminal - hydrolase - l1 ) ( park5 ) , and atp13a2 ( atpase type 13a2 ) ( park9 ) have been identified .
other studies have revealed the cytoskeletal protein tau ( mapt ) and the ligand - independent nuclear receptor nr4a2 ( nurr1 ) as susceptibility genes .
although the definite role in pd of many of these genes is still discussed and controversial ( especially for nr4a2 and uchl1 ) and the known mutations account for less than 10% of all pd cases , the investigation into the functions of the underlying genes has generated an insight into the fundamental disease pathogenesis .
for example , -synuclein and parkin turned out to be major protein components of lewy bodies in sporadic pd .
mutations in parkin , uchl1 , and dj-1 suggest that abnormal protein folding and protein degradation through the ubiquitin - proteasome system is an important factor in the etiology of the disease .
pink1 may be involved in the phosphorylation of mitochondrial proteins in response to cellular stress , thus protecting against mitochondrial dysfunction .
interestingly , mitochondria are also the site , where the known neurotoxins for da neurons operate , suggesting that their malfunctioning could be a major contributor to pd pathogenesis
. current or future searches for the underlying mutations in the remaining orphan parkinson loci could be accelerated and widened to promoter regions and to haplotype variations , if the number of candidate genes is narrowed down by other criteria .
at least seven out of the nine pd - associated genes are expressed by nigral da neurons , with different expression levels and specificity .
these are -synuclein , nr4a2 , parkin , pink1 , tau , uchl1 , and lrrk1 ( http://www.brain-map.org ) .
for this reason , we propose expression ( specific or non - specific ) by mesda neurons as a selection criterion to identify candidate genes in those pd loci where the underlying gene is still unknown ( orphan ) .
conceptually , the same method was applied on five large pd loci using serial analysis of gene expression for a comparative expression analysis of snpc and adjacent mesencephalon in postmortem brains . as cell - specific expression in mouse and human is very similar , we took three murine expression studies which employed fluorescent - activated cell sorting ( facs ) and two unrelated subtractive methods for the identification of genes expressed by mesda neurons .
we collected the cdna sequences of these expression analyses from public databases , determined the underlying genes and the corresponding gene ontology annotations [ gene ontology ( go ) ] to obtain insight into their function .
then , we established their genetic locations and their syntenic positions on the human genome . finally , we combined these data with existing human pd linkage studies .
all nucleotide sequences used in this study are publicly available at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=nucleotide and derived from three expression analyses in mouse : ( i ) barrett et al . published 779 sequences ( accession nos . :
: aa008736 , w33210w33212 , w33214w33289 , w35421w35480 , w36130w36269 , w39787w40005 , w40007w40008 , w40010w40023 , w45732 ) .
each nucleotide sequence was employed for a nucleotide - nucleotide blast ( blastn ) ( basic local alignment search tool ) on the nr database ( non - redundant ) ( http://www.ncbi.nlm.nih.gov/blast/ ) and on the mouse genome ( http://www.ncbi.nlm.nih.gov/genome/seq/mmblast.html ) .
we then recorded those alignments with the highest scores , the lowest e - values , and highest number of hits in a single locus .
blast results were categorized into four groups : ( 1 ) no significant alignments on mouse genome ( none ) , ( 2 ) significant alignments with mitochondrial dna ( mitochondrial genes ) , ( 3 ) multiple high - scoring alignments on mouse genome ( multiple hits ) for ambiguous results , and ( 4 ) significant alignments on mouse genome for single hits or otherwise unambiguous results ( table 1 ) .
genes comprises the results with high - scoring alignments in exons of single genes . in some cases , where the alignment lay in the region after the last exon or , according to the chromosome map view , in an intron of a given gene , we termed it also gene , if the hit was in a unigene cluster which was linked to the gene in the locus . with those alignments that we were unable to associate to a gene
if we could associate the sequence to a previously described est , we termed it
genomic sequence. blast results on mouse genome cdna sequences are separated into four different categories based on the types of alignments generated .
alignments on the mouse genome were subdivided into genes , ests , and genomic sequences .
genes , we differentiated further between annotated and hypothetical depending on the gene refseq status recorded at ncbi .
hypothetical genes , and mitochondrial genes , the following data were collected from the locus link feature ( http://www.ncbi.nlm.nih.gov/locuslink this was replaced by http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=gene during the course of this study ) : the gene name , gene symbol , accession number , gene i d , and the mgi link number , if available .
the latter provides a relational link to the go library and the information related to biological processes , cellular components , and
significant alignments on mouse genome , we also registered the exact chromosomal position in kilobases ( starting from the top of the short arm ) . for most of the murine genes ,
a human homolog has already been determined , normally carrying the same name and symbol .
when this information did not exist , we used the mouse protein sequence of the identified gene for a translated blast ( tblastn ) , or the nucleotide sequence of the cdna fragment or the genbank accession number of the corresponding gene for a blastn on the human genome .
we registered the position in kilobases on the chromosome and verified each position on the human genome by comparing the neighboring genes to those in the mouse genome and recorded the human position only if the neighboring genes also matched .
when the cytogenetic position on the human genome was determined , we compared this information with the positions of the recorded park loci .
we aligned the human chromosome map view with the map for morbid / disease , described in omim ( http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=omim ) . when the genes , or the estimated human locations , and the cytogenetic disease locations co - localized , we called the gene a pd candidate gene . for the loci suggested by genome - wide studies , we selected those genes , which were situated 3 mb from the chromosome marker ( single nucleotide polymorphism ( snp ) ) with the highest lod score ( table .
we are aware that this approach reduces the numbers of genes in an arbitrary manner . however ,
if preferred , the range can be widened with the provided data ( see supplementary data ) in order to more accurately consider asymmetry or size of each specific linkage peak .
the entire data set was collected and processed using the database program , filemaker pro 7.0 .
all nucleotide sequences used in this study are publicly available at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=nucleotide and derived from three expression analyses in mouse : ( i ) barrett et al . published 779 sequences ( accession nos . :
: aa008736 , w33210w33212 , w33214w33289 , w35421w35480 , w36130w36269 , w39787w40005 , w40007w40008 , w40010w40023 , w45732 ) .
each nucleotide sequence was employed for a nucleotide - nucleotide blast ( blastn ) ( basic local alignment search tool ) on the nr database ( non - redundant ) ( http://www.ncbi.nlm.nih.gov/blast/ ) and on the mouse genome ( http://www.ncbi.nlm.nih.gov/genome/seq/mmblast.html ) .
we then recorded those alignments with the highest scores , the lowest e - values , and highest number of hits in a single locus .
blast results were categorized into four groups : ( 1 ) no significant alignments on mouse genome ( none ) , ( 2 ) significant alignments with mitochondrial dna ( mitochondrial genes ) , ( 3 ) multiple high - scoring alignments on mouse genome ( multiple hits ) for ambiguous results , and ( 4 ) significant alignments on mouse genome for single hits or otherwise unambiguous results ( table 1 ) .
genes comprises the results with high - scoring alignments in exons of single genes . in some cases , where the alignment lay in the region after the last exon or , according to the chromosome map view , in an intron of a given gene , we termed it also gene , if the hit was in a unigene cluster which was linked to the gene in the locus . with those alignments that we were unable to associate to a gene
if we could associate the sequence to a previously described est , we termed it
genomic sequence. blast results on mouse genome cdna sequences are separated into four different categories based on the types of alignments generated .
alignments on the mouse genome were subdivided into genes , ests , and genomic sequences .
genes , we differentiated further between annotated and hypothetical depending on the gene refseq status recorded at ncbi .
hypothetical genes , and mitochondrial genes , the following data were collected from the locus link feature ( http://www.ncbi.nlm.nih.gov/locuslink this was replaced by http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=gene during the course of this study ) : the gene name , gene symbol , accession number , gene i d , and the mgi link number , if available .
the latter provides a relational link to the go library and the information related to biological processes , cellular components , and
significant alignments on mouse genome , we also registered the exact chromosomal position in kilobases ( starting from the top of the short arm ) .
for most of the murine genes , a human homolog has already been determined , normally carrying the same name and symbol .
when this information did not exist , we used the mouse protein sequence of the identified gene for a translated blast ( tblastn ) , or the nucleotide sequence of the cdna fragment or the genbank accession number of the corresponding gene for a blastn on the human genome .
we registered the position in kilobases on the chromosome and verified each position on the human genome by comparing the neighboring genes to those in the mouse genome and recorded the human position only if the neighboring genes also matched . when the cytogenetic position on the human genome was determined , we compared this information with the positions of the recorded park loci .
we aligned the human chromosome map view with the map for morbid / disease , described in omim ( http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=omim ) .
when the genes , or the estimated human locations , and the cytogenetic disease locations co - localized , we called the gene a pd candidate gene . for the loci suggested by genome - wide studies , we selected those genes , which were situated 3 mb from the chromosome marker ( single nucleotide polymorphism ( snp ) ) with the highest lod score ( table . 5 ) .
we are aware that this approach reduces the numbers of genes in an arbitrary manner . however ,
if preferred , the range can be widened with the provided data ( see supplementary data ) in order to more accurately consider asymmetry or size of each specific linkage peak .
the entire data set was collected and processed using the database program , filemaker pro 7.0 .
we obtained 1435 sequences from three independent studies , which had the original aim to identify genes expressed by mesda neurons .
the other two studies used subtractive methods to enrich for rare rna transcripts expressed by mesda neurons .
had created a single - stranded directional cdna library from substantia nigra of 8-week - old mice subtracted with a cdna library from cerebellum .
we had used a pcr - based differential display method employing cdna from engrailed-1/2 double - mutant and wild - type ventral midbrain during the embryonic stages when mesda neurons disappear in the mutants .
the amplified sequences were compared to the expression profile of adult olfactory bulb , a source of da neurons unrelated to those in the ventral midbrain . only differentially expressed cdna fragments were isolated and sequenced . as the original sequence analyses of the former two studies had been performed when a smaller nucleotide data set was available and in order to update our own expression analysis , we subjected the sequence data from all three screens to new blast searches and determined their association to genes and published ests , and their location on the mouse genome .
the 1435 cdna fragments generated 1050 unambiguous murine genomic hits , 19 ambiguous multiple hits , and 104 alignments with mitochondrial dna .
two hundred and sixty - two cdna sequences produced no significant alignments ( see table 1 for definitions and the entire analysis , and table 2 for the individual libraries ) .
hypothetical genes determined by est clustering or predicted by automated computational genome analysis with a large open reading frame . expressed sequencing tags .
five hundred and seventy - nine unique tags were on the mouse genome ( excluding mitochondria ) .
number of fragments that represent genes , hypothetical genes , ests , genomic sequences , multiple alignments , and mitochondrial genes , listed per individual library .
out of 1050 cdna fragments , which generated unambiguous alignments on the mouse genome , 1020 were in gene loci .
most of them aligned to exons of those genes ( 72.6% ; 741 of 1020 ) .
out these 1020 cdna fragments , 181 ( 17.8% ) lay 3 to the last annotated exon , suggesting that substantial amounts of mrnas isolated from brain tissue are longer at their 3 end than mrnas from other tissues ( table 3 ) .
finally , 9.6% ( 98 of 1020 ) of the alignments lay in regions designated as introns , suggesting that they are parts of unrecorded splice variants , possibly specific for mesda neurons .
alignments in relation to gene loci genomic alignments were divided into three groups : ests ( 3.7% ) ,
majority of the cdna fragments that aligned with genes are aligned with the last exon . a significant number of the cdnas aligned with the region 3 to the last exon . see material and methods for details .
the 1050 cdna fragments represented 503 genes ( 423 annotated and 80 hypothetical genes ) , 32 ests , and 44 unique genomic hits with no otherwise described ests .
additionally , the 104 sequences that aligned to the mitochondrial dna represented 11 mitochondrial genes ( table 2 ) .
this provided us with insight into their molecular function , the cellular locations of the proteins , and the associated biological process ( see supplementary data for the entire transcriptome analysis ) .
several protein classes were over - represented , like , for example , those , which take part in mitochondria - related processes , in fatty acid chain metabolism , in ubiquitination , in the mapk signaling pathways , or which are chaperones .
some of these molecular pathways were previously linked to the death of mesda neurons , to pd , and other human neurodegenerative disorders .
the majority of the mutations , which are associated to pd , is in genes that are expressed in mesda neurons .
we , therefore , joined these expression analyses with human pd linkage and association studies , where no mutation has been associated thus far .
for each unique mouse cdna sequencing tag , we determined its human homolog and the corresponding cytogenetic and physical positions on the human chromosomes .
we verified each locus on the human genome by identifying the neighboring genes on the mouse genome and recorded the human position only if the adjacent genes were the same .
we then determined whether these positions were within omim ( table 4 ) and other suggestive ( non - omim ) pd loci ( table 5 ) . in case of the omim orphan pd loci , we projected on the human chromosome view the map for morbid diseases. in case of non - omim loci , we identified the genes 3 mb to the snp marker with the highest lod score .
totally , we linked the mouse transcriptome analyses to 569 unique locations on the human genome .
nineteen of these are within orphan park loci ( table 6 ) and 51 in non - omim pd loci ( table 7 ) .
genomic location of park loci as recorded in the omim databank . for seven of the park loci
the number of genes is the current genbank estimation of all annotated and predicted genes in the corresponding park locus . for the park10 locus
, we used the narrow definition 1p33 - 1p32.2 as determined by the two genetic markers d1s2134 and d1s200 , and not the entire shorter arm of chromosome 1 ( 1p ) which contains 1232 genes .
association studies not recorded at omim for each individual study , the highest lod scores with the associated genetic markers are listed . in these studies , the peak positions and the flanking genetic markers
we determined , when possible , the exact position in mb on the corresponding chromosome .
the average distance between the two adjacent genetic markers in each study varied between 5 and 11 cm .
candidate genes in orphan park loci candidate genes for non - omim park loci listed genes are situated 3 mb to peak with the highest lod score , except for d10s196 where we used 8 mb .
the experimental design of the three different transcriptome analyses , we used for our study , were such that they included both highly and rarely expressed transcripts .
only 7.2% ( 104 out of 1435 ) of the cdna sequences of these libraries represent genes , hypothetical genes , or est clusters , which are found in more than one of them ( table 8) .
moreover , the libraries also contained two cdna fragments for -synuclein , three for nr4a2 , and one for the tau genes .
assuming that all 30 000 genes in the human genome were equally likely detected , the probability to identify three of nine pd susceptibility genes by chance out of a pool of 569 was less than 3.4 10 . if we exclude the controversial nr4a2 and uchl1 , the probability was less than 1.5 10 .
cdna library comparison of 1435 , 104 ( 7.2% ) cdna fragments overlap with sequences also present in one other library .
this number includes not only fragments that align with each other , but also those which align with the same annotated gene , hypothetical gene , mitochondrial gene , est , or genomic position .
these overlapping 104 cdna fragments represent 28 of 781 ( 3.6% ) unique tags ( table 2 ) .
the entire human and mouse genome sequences have been available for more than 3 years .
therefore , the chromosomal locations of most genes have been determined and as a consequence also those genes within a given disease locus . in order to identify potential pd susceptibility genes , we projected the sequence data of three murine transcriptome studies for mesda neurons onto the human genome and compared them with previously identified pd loci .
we determine the human homologs of 1435 murine cdna fragments which corresponded to 579 unique mouse chromosomal locations ; 423 annotated genes , 80 hypothetical genes , 32 ests , and 44 genomic locations , which are not linked to any genes or otherwise reported cdna sequences .
of the 569 unique locations on the human genome , 19 were positioned in omim park loci and 51 within genomic regions that have a weaker linkage to pd , which are not recorded in the omim database and need further confirmation .
multiple studies are on the way to determine the underlying mutations of orphan park loci ; however , the length of putative regulatory regions of most gene , their unpredictable position , and the common presence of snps have thus far restricted such studies to nucleotide variation in the coding region and in 5 and 3 utr .
silencer regions were only the aim if the targeted gene had been previously linked to pd .
a nucleotide variation in the -synuclein promoter , for example , was associated to the disease .
variability on the level of gene expression is far more common than nucleotide variations which alter protein sequences and it is believed that these haplotype variations determine individual traits and predispositions for common diseases such as pd .
narrowing down the number of candidate genes in identified loci in a rational manner may encourage the inclusion of the promoter regions in future studies aiming to identify mutations associated to pd . among the candidate genes that we found ,
the most interesting is vmat2 ( vesicular monoamine transporter 2 ) ( 10q25 ) . reduced expression of vmat2 could be correlated with a higher sensitivity to environmental factors .
for example , vmat2 heterozygote mice ( + / ) are remarkably more sensitive than wild - type to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine .
furthermore , we identified two genes in the ubiquitination pathway , ube2b [ ubiquitin - conjugating enzyme e2b , rad6 homology ( s. cerevisiae ) ] and ubb ( ubiquitin b , member of the hsp90 family ) and hspa5 ( heat shock 70 kda protein 5 , member of the hsp70 family )
. finally , 26 mitochondrial genes encoded by nuclear dna are present in our transcriptome analysis . of these , an unexpected high proportion of genes , namely four , are located within orphan omim park loci .
there is increasing evidence that impairment of mitochondrial functions and oxidative stress are contributing factors to pd supported by the recent finding of a mutation in pink1 .
furthermore , the functional deficiencies induced by several of the other pd mutations seem to converge onto the mitochondria .
our finding confirms a central role of the mitochondria in pd and suggests the possibility that a misregulation of some of these four mitochondrial genes may be a contributing factor for the disease .
we conclude that our transcriptome analysis , along with being applicable for the identification of pd candidate genes , may also be a useful tool for future genome - wide association studies with newer resources , such as hapmap ( http://www.hapmap.org/ ) , where tagsnps can be chosen close to loci of genes expressed by mesda neurons .
furthermore , new go annotations are constantly added and with time it may turn out that many of the identified genes are part of shared metabolic pathways .
our data set may give new insight into ligand / receptor interactions and/or intracellular signaling pathways acting in mesda neurons , allowing novel studies into the molecular etiology of pd .
| ### Summary:
: abstractthe hallmark of parkinson 's disease ( pd omim # 168600 ) is the degeneration of the nigral dopaminergic system affecting approximately 1% of the human population older than 65 . in pursuit of genetic factors contributing to pd , linkage and association studies identified several susceptibility genes .
the majority of these genes are expressed by the dopamine - producing neurons in the substantia nigra .
we , therefore , propose expression by these neurons as a selection criterion , to narrow down , in a rational manner , the number of candidate genes in orphan pd loci , where no mutation has been associated thus far .
we determined the corresponding human chromosome locations of 1435 murine cdna fragments obtained from murine expression analyses of nigral dopaminergic neurons and combined these data with human linkage studies .
these fragments represent 19 genes within orphan omim pd loci .
we used the same approach for independent association studies and determined the genes in neighborhood to the peaks with the highest lod score value .
our approach did not make any assumptions about disease mechanisms , but it , nevertheless , revealed -synuclein , nr4a2 ( nurr1 ) , and the tau genes , which had previously been associated to pd .
furthermore , our transcriptome analysis identified several classes of candidate genes for pd mutations and may also provide insight into the molecular pathways active in nigral dopaminergic neurons . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the danish national quality database for births ( dnqdb ) started out as a part of the danish national indicator project ( dnip ) in 2010.1,2 the aim of the database is to measure the quality of the care provided during labor and birth through specific indicators . in the context of the database ,
birth is defined as the time from a woman s arrival at a maternity unit / labor ward until 2 hours after the birth .
the indicators related both to the woman giving birth and to the child(ren ) . births in denmark are approximately 55,00060,000 per year , of which 1.5% are home births .
the accumulated number of births and children included in the database as of august 31 , 2015 were 269,597 and 274,153 , respectively .
childbirth is a complex clinical situation , sometimes involving specialists from more than one department . because of this
, the indicators and the standards adopted were decided by a group of clinicians that included midwives , obstetricians , a pediatrician , anesthesiologists , and an epidemiologist . to decide which parts of the birth process to cover and include in the dnqdb , a schematic
initially , eight indicators were selected , to fit within the upper limit of 810 set by the dnip . guiding factors for selection were relevance , scientific evidence , acceptability , and patient safety.1,2 further details on the indicators selected and the reasons for excluding other potential indicators are available elsewhere.2 subsequently , some of the indicators were extended , and an additional outcome indicator was included in 2013 concerning the proportion of acute cesarean sections ( grade 2 ) performed under local anesthesia .
data from this indicator are not included in the analyses in tables 1 and 2 because only 2 years of data have been collected , making it as yet invalid for comparison .
all the quality indicators are process and outcome indicators concerning care during and after labor .
further information on the indicators and the data definitions are given in kesmodel and jlving.2 all data for the dnqdb are collected from the danish medical birth registry.3 registration to the danish medical birth registry is mandatory for all maternity units in denmark .
after an initial period of inaccuracies in registration and of getting used to new registrations designed for the database , the data completeness is now very high ( > 90% for the indicators in tables 1 and 2 with apparently no or little selection bias ) , and the results are therefore considered reliable .
measuring quality appears to have inspired improvements in performance , locally , within the clinical units , as there has been a great effort to perform well in the areas measured by the database . during the 5 years
studied so far , performance has improved in the areas covered by process indicators and also for some of the outcome indicators .
the comparison shown in tables 1 and 2 , between data from the second year of the database ( 2012 ) and the latest year ( 2015 ) , reveals a significant reduction in the proportion of first - time deliveries complicated by third and fourth degree lacerations , as well as a significant increase in both the proportion of cesarean sections carried out within the time recommended and the proportion of epidural / spinal given within 1 hour from prescription .
likewise , significantly more women now have continuous support during the active phase of the labor .
in addition to reducing complications and improving organizational processes , the act of collecting data for the dnqdb has also resulted in measurements that are more accurate .
an example is the exact amount of bleeding during birth . because of this focus on the accurate measurement of this indicator , we now know that maternal bleeding during birth is more extensive than previously suspected .
we assume this not to be due to a real increase but to a new and continuous focus on measuring the bleeding correctly , in this case by objective weighing rather than guessing .
another example , which presents a similar difficulty in the comparison of results from the last 5 years , is the proportion of children with fetal hypoxia . in this indicator , hypoxia is defined as ph < 7 . 0 or ,
if ph is not measured , apgar score < 7 after 5 minutes . during the 5-year period
, there has been an increase in the proportion of births with umbilical cord ph measurement , which compromises the ability to compare data across the years .
as well as focusing on quality locally , each unit has also been inspired to cooperate with other units and to integrate experience obtained elsewhere .
interestingly , the risk of birth complicated by a severe laceration is now almost the same in all maternity units no matter in which part of denmark the birth takes place ( table 2 ) . during the 5 years that the dnqdb database has existed , there have been changes in the measurement of quality in childbirth and pregnancy in denmark .
when the database started , the database of the danish healthcare quality program ( ddkm ) included indicators concerning pregnancy and maternity.4 however , these ddkm indicators no longer exist .
because of this , new indicators are currently being selected by the group of clinicians behind the dnqdb database .
these will measure the quality of care in pregnancy , thereby potentially extending the period covered by this database hitherto .
a part of this work is done in cooperation with the national fetal medicine database.5 this new cooperation between the two databases is important and can be extended in time . the measurement of quality during maternity will be a subject for indicators in the future .
the group of clinicians involved in the project currently meet every year before publishing the annual national report ( available from http://www.kcks-vest.dk/kliniske-kvalitetsdatabaser/foedsler/ or on request from the authors ) .
every year all the indicators are reevaluated , and the need for new indicators is considered .
most epidemiologic research concerning birth in denmark is by tradition based on data collected from the danish medical birth registry .
the service offered by the danish medical birth registry has changed in recent years , making it more difficult and time consuming to access data for research and quality improvement .
because of this , using data from the dnqdb can be an advantage for researchers . access to the dnqdb data via the registry support centers of epidemiology and biostatistics ( south )
is not only quicker and easier but the dnqdb data are also refined and analyzed by an epidemiologist before being delivered to the researchers .
after 5 years of collecting data , the dnqdb data are now very comprehensive and reliable .
this gives the opportunity to plan large - scale projects based on data and experience from the dnqdb .
the first step in this process is to get access to more data from the danish medical birth registry .
like most other national clinical quality databases in denmark , the dnqdb is funded by the five danish regions that administer and finance the public health care system in denmark .
key information is reported immediately after birth by the attending midwife to the ( national ) danish medical birth registry , administered by the danish health and medicines authority .
subsequently , relevant data are drawn from the registry by the registry support centres of epidemiology and biostatistics ( south ) , which then refines it and performs relevant analyses based on the fixed formulas decided by the database steering committee . | ### Summary:
: aim of the databasethe aim of the danish national quality database for births ( dnqdb ) is to measure the quality of the care provided during birth through specific indicators.study populationthe database includes all hospital births in denmark.main variablesanesthesia / pain relief , continuous support for women in the delivery room , lacerations ( third and fourth degree ) , cesarean section , postpartum hemorrhage , establishment of skin - to - skin contact between the mother and the newborn infant , severe fetal hypoxia ( proportion of live - born children with neonatal hypoxia ) , delivery of a healthy child after an uncomplicated birth , and anesthesia in case of cesarean section.descriptive datadata have been collected since 2010 . as of august 2015 ,
data on women and children representing 269,597 births and 274,153 children have been collected .
all data for the dnqdb is collected from the danish medical birth registry .
registration to the danish medical birth registry is mandatory for all maternity units in denmark . during the 5 years
, performance has improved in the areas covered by the process indicators and for some of the outcome indicators.conclusionmeasuring quality of care during childbirth has inspired and enabled staff to attend to the quality of the care they provide and has led to improvements in most of the areas covered . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: dubai is the largest of the seven emirates comprising the united arab emirates ( uae ) ( fig . 1 ) .
arabic is the official language of dubai , but english is widely spoken in the medical and business settings , and medical training and practice largely follow a western model .
practice in dubai is advancing rapidly , and the emirate is poised to become a regional leader in em care .
map from central intelligence agency world factbook ( https://www.cia.gov/library/publications/the-world-factbook/geos/ae.html ) united arab emirates map , showing the location of the emirate of dubai . map from central intelligence agency world factbook ( https://www.cia.gov/library/publications/the-world-factbook/geos/ae.html ) this report describes the structure of the health - care system in dubai , with particular emphasis on em .
it examines medical education , the organization of health - care services , emergency department ( ed ) structure , and the challenges facing em .
information from dubai s department of health and medical services ( dohms ) , the ministry of health ( moh ) for the uae , hospital visits and physicians practicing emergency medicine in dubai provided material for this report .
dubai s rapid economic expansion began several decades ago with the discovery and export of oil , and has since been further fueled by the emirate s status as a tax - free port .
the foundations of its economy are now trade , manufacturing and financial services ; only 6% of dubai s gross domestic product comes from oil .
a significant result of dubai s economic growth is an investment in medicine and improvement in the standard of medical care . as the health - care infrastructure has expanded
including the construction of clinics , hospitals , specialized care centers and postgraduate teaching facilities representation of em and other medical specialties has also increased .
the population of dubai is estimated to be 1.65 million people , of which 76% are male .
of the total population , only about 17% are uae nationals ; most of the remainder are guest workers from india , pakistan , bangladesh and the philippines .
the median age is 32 years for males and 24.5 years for females .
the infant mortality rate was estimated at 8.0 deaths per 1,000 live births in 2007 .
health care in dubai is provided primarily by expatriate physicians from the middle east , india , pakistan , canada and the uk , in addition to some emirati physicians ; nursing staff in hospitals and clinics originate largely from india and the philippines .
licensure is granted by the dubai health authority ( a division of the dohms ) after demonstration of equivalency training and licensure from the practitioner s home country .
em in dubai is well developed , with an advanced physical infrastructure , diagnostic equipment and therapies available in most hospitals .
two large government - run tertiary care centers , dubai hospital and rashid hospital , provide all medical and surgical subspecialties .
rashid is also the site of the first postgraduate em training program in the uae .
medical and surgical postgraduate training programs exist in both the government hospital system and the private system , and more are planned in the near future . a new multidisciplinary provider of inpatient and outpatient services , dubai health care city ( dhcc ) , is expected to be complete in 2011 .
dhcc is designed as a regional center of excellence in clinical care , education and research . a private enterprise ,
postgraduate medical education and research programs are affiliated with harvard university , and dental education and research programs are affiliated with boston university . when dhcc is complete
, it will add 18 specialty hospitals , including a 400-bed academic medical center and 2,125 new inpatient beds , to dubai s medical infrastructure .
the academic medical center will include a 36-bed ed , capable of accommodating 50,000 patient visits annually .
a hospital - based ems service is planned at this facility and will provide service cooperatively with the dohms ambulance services .
after completion of the us equivalent of high school , students attend medical school for 5 years .
the only medical school in dubai is the dubai medical college for girls , a private institution that accepts 100 students per class .
the uae has three other medical schools , the largest of which is the government - funded emirates university medical school in al ain [ 1416 ] .
postgraduate training is available in internal medicine , surgery , obstetrics and gynecology , pediatrics , family medicine , community medicine , psychiatry and emergency medicine .
the training structure follows the british system , with trainees progressing through senior house officer , registrar , senior registrar , specialist registrar and finally consultant ( the equivalent of attending in the us ) .
faculty members monitor clinical performance and have didactic programs similar to those available at teaching hospitals in the united states .
dubai has one em training program for physicians . the inaugural class , consisting of ten residents representing six countries , started their training at rashid hospital in july 2008 .
among the prerequisites for admission are the completion of a transitional year , an entrance interview and a passing grade in the intern exam administered by the dohms .
a new residency program in em is anticipated at dhcc when it opens in 2011 .
board examination and certification for qualified candidates are expected through the british board of emergency medicine for graduates of the government program .
dubai is in the process of developing new accreditation standards , which will also apply to em .
the largest em conference in dubai is the annual dubai international emergency and catastrophe management conference ; in addition , the nascent society of emergency medicine holds biannual dinner meetings .
dubai is almost entirely urban , and health care is delivered though government and private hospitals , clinics and private medical practices . in 2006 , dubai had 24 hospitals with a total inpatient capacity of more than 2,600 inpatient beds and 200 intensive care beds .
approximately two - thirds of the inpatient beds were at government - funded facilities , under the dohms or moh .
all venues are staffed by physicians and registered nurses ; mid - level providers are not recognized by the dohms or moh .
the government operates a collaboration of outpatient clinics that take care of the primary health care needs of uae nationals and guest workers .
all except for the most trivial trauma are referred to the rashid hospital trauma center .
dubai is in the process of converting to a national insurance plan that would allow individuals to seek acute care in the hospital of their choice .
dubai has a centralized ems system that dispatches 120150 ambulances per day [ 18 , 19 ] .
the center of ambulance services ( coas ) was created in 2006 , merging the services of the dubai police and the dohms , the latter of which had previously offered only inter - facility transportation . call reception and ambulance dispatch are provided by the dubai police and coas personnel assigned to police communications .
coas operates approximately 40 ambulances daily , including 2 mobile intensive care units and 67 fast - responder units and motorcycles .
four paramedics ( a term used to describe all levels of prehospital providers ) are assigned to police helicopter duty .
paramedics are also assigned to the communications center , clinics , the airport and to support unit arrival at rashid and dubai hospitals .
fast - responder units ( sport utility vehicles ) and motorcycles are utilized in heavily congested and high - demand areas to reduce response times .
currently four motorcycles are deployed in the two most congested areas of dubai and are available 16 h daily , except during inclement weather and during the hottest months of the year .
these units do not typically transport patients , although this does happen during times of system overload ( coas administration , personal communication ) . receiving hospitals for coas ambulances are primarily rashid and dubai hospitals .
dubai hospital is the receiving facility for all medical patients except for suspected neurologic , cardiac and gastrointestinal patients , who are transported to rashid or specialty hospitals .
transport decisions are made in the field using triage protocols , if necessary in consultation with medical control .
one major system difference between dubai and western countries is the absence of a good samaritan law .
although such legislation is in the works , the current lack of protection reduces first - responder intervention .
poor penetration of basic life support skills among the general public also significantly limits this component of the ems system .
another limitation is the lack of education among the public regarding when to activate ems .
patients with serious conditions such as acute myocardial infarction or stroke are often transported by private car instead of ambulance .
a growing number of hospitals and clinics serve the dubai population . the systems and equipment necessary to perform the highest level of emergency medical care , including well - equipped and staffed eds , intensive care units , operating rooms , laboratories , and radiological and other diagnostic services , are widely available .
private hospitals may have as few as 25 inpatient beds , and not all have eds .
al wasl hospital , a dohms facility , has a 24/7 ed specializing in pediatric and obstetrical care .
it is a 400-bed facility , with an annual ed census of 140,000 patients a year .
the hospital provides postgraduate training in medicine and surgery , as well as the new em program .
the ed population is integrated within a single receiving area ; approximately 60% are surgical and 40% have medical complaints .
acute traumatic emergencies are common due to the high incidence of industrial injuries , especially to the head and hands .
motor vehicle - related trauma is also common ; contributing factors include poor seatbelt compliance and lack of car seat use for children .
approximately 50 patients per day are transferred by ambulance to the ed at rashid hospital .
the remainder arrive by car , taxi , bus or on foot ( rashid hospital ed staff , personal communication ) .
the ed at rashid is staffed by seven physicians at a time during peak hours .
many of these physicians have years of postgraduate training and function independently . attending physicians with recognized credentials in em from the us , canada and the uk supervise during the daytime and are available to consult on difficult cases .
one attending physician serves as the department head and has administrative responsibility for the ed .
if a patient is critically ill , specialists from general surgery , trauma surgery , orthopedics , urology , oromaxillofacial surgery , otolaryngology and neurosurgery can be summoned to the ed 24/7 .
patients felt to be in need of emergency surgery are taken immediately to the operating room after stabilization in the ed .
welcare hospital , one of the larger private facilities , has 210 inpatient beds and an annual ed census of approximately 72,000 annual visits .
welcare is a major provider of obstetrical services and averages approximately 160 births / month .
welcare also has its own hospital - based ems services , staffed by eight paramedics and its own ambulances .
the development of em in dubai is advanced compared with other locations in the middle east .
medical resources , including infrastructure , highly trained physicians and nurses , and an extensive ems system have all strengthened em in dubai .
dubai also has in place a major disaster contingency plan that encompasses dohms , moh , government and private hospitals , and ems .
although the practice of em is advanced , the coordination and standardization of efforts among the various private , governmental and teaching hospitals is limited .
such coordination is likely to improve through the development of postgraduate training programs in the near future .
state - of - the art teaching facilities , including a medical simulation center , are expected to be complete within the next 3 years .
in addition , continuing medical education programs and a board certification process in em have been initiated , and linkages with foreign universities with strong em programs have been established .
it the future , the development of a regional or national program for accreditation in em will be important .
a recognized professional organization dedicated to em will serve to strengthen the specialty and coordinated and standardized emergency care throughout dubai , and eventually throughout the uae .
another major challenge for em in dubai is rapid expansion of the population , which is expected to double to 3.4 million by 2015 .
this challenge is being addressed through the construction of the dhcc and other private hospitals . when completed
, these facilities will provide more than 3,400 additional inpatient beds and will shift the majority of inpatient beds from the public to the private sector .
physicians with ed experience staff most eds . however , board certified or board eligible ( bc / be ) emergency physicians are lacking .
this results in ed supervision by bc / be emergency physicians occurring only during the busiest parts of the day ; at other times , bc / be coverage is through telephone consultation .
however , the completion of the academic medical center at dhcc will present an opportunity to develop em teaching and research .
community intervention , especially in the discipline of injury control , will also be paramount .
establishing a trauma systems registry will be required to improve the overall delivery of trauma care . as dubai continues to expand economically , provision of emergency medical care
dubai may soon have one of the most advanced systems of emergency care in the middle east , which will be a model for other emirates in the uae and other regional countries to follow . | ### Summary:
: dubai has rapidly risen to prominence in the persian gulf region as a center of global commerce and tourism and as a cultural crossroad between east and west .
the health - care infrastructure has undergone rapid development .
collaborations with academic medical centers now exist to advance clinical care , teaching and research .
emergency medicine has also advanced and is undergoing dynamic change .
dubai may soon emerge as a regional leader in emergency medicine training and practice . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: homeobox ( hox ) genes are essential developmental regulators that control a wide range of processes , including apoptosis , differentiation , motility , and angiogenesis . in humans , there are four hox clusters ( a , b , c , and d ) , and 39 hox genes have been identified .
the hox genes are normally active during embryogenesis , but most are not expressed or are expressed at very low levels in an adult brain . on the other hand , several studies have indicated aberrant expression of the hox genes in brain tumors as well in as other cancers from various organs [ 3 - 6 ] . moreover , there is growing clinical evidence of a prognostic effect of hox gene expression in several cancers [ 7 - 10 ] .
aberrantly expressed hox genes in cancer cells have multicapacity functions , including metastasis , tumor growth , anti - apoptosis , and differentiation suppression .
the overexpression of multiple hox genes have been observed in glioblastoma ( gbm ) cell lines and primary astrocytoma .
in addition , some studies have shown that the hox genes are important in the treatment resistance of gbm [ 11 - 13 ] . on the other hand ,
the precise mechanism showing the role of hox genes and their functional relevance in glioma cells is unclear .
gbms , similar to other cancers , harbor a cell subpopulation with a stem cell - like capacity that is associated with the development of a tumor progeny and treatment resistance . given the roles of hox genes in development and organogenesis
, it has been postulated that a portion of the relative expression of hox genes is integral to stem cell activity , specifically self - renewal , tissue specificity , and quiescence . among the hox genes ,
the hoxa cluster is important in human embryonic stem cell differentiation . collectively , these results suggest that hox genes are plausible candidates as biomarkers for assessing the prognosis of gbm and a credible target for overcoming the treatment resistance in gbm .
hox genes were previously reported to be the genes of interest related to gbm recurrence and treatment resistance . moreover ,
a mechanism through which the hoxa10 gene affects temozolomide ( tmz ) resistance in gbm cell lines was reported .
hoxa10 induces the transcription of early growth response 1 , which results in phosphatase and tensin homolong ( pten ) and rad51 paralogs . as a result ,
the homologous recombination dna repair system with rad51 genes can protect cancer cells from tmz - induced cytotoxicity . in the present study ,
this research was extended to another hox gene , hoxa11 , and its role in gbm prognosis was examined .
fresh frozen tumor tissue samples of five gbm patients , in whom of pairs of initial and recurrent samples were available for screening , and another 20 newly diagnosed gbm patients for validation were used in this study .
all patients were managed using a standard gbm treatment protocol of concurrent radiotherapy and tmz treatment , followed by adjuvant tmz as a primary treatment .
the tumor tissues were obtained during surgery , snap - frozen in liquid nitrogen , and stored at 80c prior to use .
the human glioma u251 , u373 , and ln18 cell lines were purchased from the american type culture collection ( manassas , va ) , and cultured in dulbecco 's modified eagle 's medium containing 10% fetal bovine serum and 5% antibiotics ( streptomycin ) in a humidified atmosphere containing 5% co2 and 95% air at 37c .
the cell lines were lysed with trizol ( life technologies , carlsbad , ca ) , and rna isolation was performed using an rneasy mini kit ( # 74104 , qiagen , valencia , ca ) .
in addition , cdna was synthesized from 1 g of the total rna using a reverse transcription kit ( # 205311 , qiagen ) according to the manufacturer s protocol .
the primers used were designed using an online primer - blast tool ( http://www.ncbi.nlm.nih.gov/tools/primer-blast/ ) .
the primer sequences for hoxa11 were 5'-gatttctccagcctcccttc-3 ' ( forward ) and 5'-agaaattggacgagactgcg-3 ' ( reverse ) . using these primers , a reverse transcription polymerase chain reaction ( rt - pcr ) was performed for 35 cycles .
each cycle was comprised of 95c for 30 seconds , 62c for 30 seconds , and 72c for 45 seconds with each primer set .
the whole protein extracts from the tissue samples were prepared using a pro - prep lysis buffer ( # 17081 , intron biotechnology , seongnam , korea ) , and the protein concentrations were determined using a bicinchoninic acid protein assay ( # 23227 , thermo fisher scientific , waltham , ma ) .
the proteins were separated using 10% sodium dodecyl sulfate polyacrylamide gel electrophoresis , followed by blotting onto nitrocellulose membranes , and probing with the antibodies against hoxa11 ( # sc-48542 , 1:500 dilution , santa cruz biotechnology , santa cruz , ca ) .
the blotted membranes were then incubated with the goat anti - rabbit igg secondary antibody for 1 hour .
subsequently , the membranes were incubated in an amersham ecl - prime solution ( # rpn2232 , ge healthcare life sciences , pittsburgh , pa ) in the dark for 1 minute and exposed under fluorchemhd2 ( cell biosciences , santa clara , ca ) for visualization . only the samples with a consistent result from repeated experiments were selected for analysis .
the densities of the bands were measured using free image analyzer software ( imagej v1.8x , national institutes of health , http://rsb.info.nih.gov/ij/ ) .
the results are presented as the meanstandard error of mean calculated from independent samples . to knock down hoxa11 expression in cells ,
small interfering rna ( sirna ) experiments were performed using commercially available sequences targeting hoxa11 ( # sasi - hs01 - 00110410 , # sasi - hs01 - 00110413 , and # sasi - hs01 - 00110417 , sigma aldrich , st .
louis , mo ) as well as with the non - targeting control sirna ( # d-001610 - 01 - 05 , dharmacon , lafayette , co ) .
when the cells reached 70%-80% confluence , they were transfected with sirna under the most efficient transfection condition , as determined by the neon transfection system ( # mpk5000 , life technologies ) .
the cells were cultured in media without antibiotics to increase the sirna transfection efficiency for 24 hours .
the control and transfected cells were grown on 96-well plates at a density of 410 cells per well for 24 hours .
subsequently , the cells were either treated with tmz ( # alx-420 - 044-m100 , enzo life sciences , farmingdale , ny ) to a final concentration of 300 g / ml for 24 hours or irradiated with 4 mv x - rays from a linear accelerator ( clinac 4/100 , varian medical systems , palo alto , ca ) at a dose rate of 10.0 gy / min . for the combination treatment , the cells were irradiated first and then treated with tmz .
cell viability analysis was performed using a colorimetric cell counting kit-8 ( cck ; dojindo molecular technologies , kumamoto , japan ) .
the number of viable cells was quantified according to the manufacturer s instructions by reading the ultraviolet absorption spectra at 450 nm on a microplate 2 hours after adding 10 l of a cck solution per well .
the total rna was extracted from the tissue samples using the mirvana mirna isolation kit ( # am1560 , ambion , austin , tx ) for microarray analysis after quantification and qualification .
the total rna quality was determined using an agilent 2100 bioanalyzer ( agilent technologies , santa clara , ca ) .
the cut off rna integrity number for rna used in rna amplification was 7.0 or above .
the crna was produced using an illumina totalprep rna amplification kit ( # il1791 , ambion ) according to the provided protocol .
the crna was used for hybridization to a human ht12-v4 illumina beadchip gene expression array ( illumina , san diego , ca ) according to the manufacturer s protocol .
the arrays were scanned and the fluorescence signals were obtained using an illumina beadarray reader ( beadstation 500gxdw , illumina ) .
the signal obtained from the scanned beadchip was transformed to intensity raw data using genomesortudio software ( ver .
the raw data were normalized by applying a log2 transformation , quantile normalization , and gene and array centering .
2.14 , http://www.bioconductor.org ) . to determine the changes in gene expression before and after hoxa11 knockdown ,
the total rna extracted from the ln18 cells transduced with sihoxa11 or control sirna were analyzed by affymetrix genechip human gene 1.0st arrays ( affymetrix , santa clara , ca ) .
the rna was amplified and labeled using a genechip wt sense target labeling and control reagents kit ( affymetrix ) .
the cdna was synthesized , labeled , and hybridized to the genechip array according to the manufacturer 's protocol .
the genechips were washed and stained using the genechip fluidics station 450 ( affymetrix ) , and then scanned using a genechip scanner 3000 7 g ( affymetrix ) .
1.1 ( affymetrix ) was used to compare the group signals , and the data were logtransformed ( base 2 ) for parametric analysis .
the differentially expressed genes ( degs ) were identified by significance analysis of the microarrays method in the r package samr ( r 2.11.1 ) .
the data from the experiments were tested for their significance using an unpaired two - tailed student 's t test .
an anova and student 's t test were used to identify the significant differences in cell death rates .
the results were analyzed using ibm spss statistics software ver . 19.0 ( ibm co. , armonk , ny ) .
for microarray analyses , the false discovery rates ( fdrs ) were calculated using three genepattern software modules ( http://www.broadinstitute.org/cancer/software/genepattern ; comparativemarkerselection ver .
the significantly regulated genes were subjected to functional gene classification using the david bioinformatics resources annotation tool ( ver .
the selected gene ids of the identified degs were entered into genemania software ( ver .
fresh frozen tumor tissue samples of five gbm patients , in whom of pairs of initial and recurrent samples were available for screening , and another 20 newly diagnosed gbm patients for validation were used in this study .
all patients were managed using a standard gbm treatment protocol of concurrent radiotherapy and tmz treatment , followed by adjuvant tmz as a primary treatment .
the tumor tissues were obtained during surgery , snap - frozen in liquid nitrogen , and stored at 80c prior to use .
the human glioma u251 , u373 , and ln18 cell lines were purchased from the american type culture collection ( manassas , va ) , and cultured in dulbecco 's modified eagle 's medium containing 10% fetal bovine serum and 5% antibiotics ( streptomycin ) in a humidified atmosphere containing 5% co2 and 95% air at 37c .
the cell lines were lysed with trizol ( life technologies , carlsbad , ca ) , and rna isolation was performed using an rneasy mini kit ( # 74104 , qiagen , valencia , ca ) .
in addition , cdna was synthesized from 1 g of the total rna using a reverse transcription kit ( # 205311 , qiagen ) according to the manufacturer s protocol .
the primers used were designed using an online primer - blast tool ( http://www.ncbi.nlm.nih.gov/tools/primer-blast/ ) .
the primer sequences for hoxa11 were 5'-gatttctccagcctcccttc-3 ' ( forward ) and 5'-agaaattggacgagactgcg-3 ' ( reverse ) . using these primers , a reverse transcription polymerase chain reaction ( rt - pcr ) was performed for 35 cycles .
each cycle was comprised of 95c for 30 seconds , 62c for 30 seconds , and 72c for 45 seconds with each primer set .
the whole protein extracts from the tissue samples were prepared using a pro - prep lysis buffer ( # 17081 , intron biotechnology , seongnam , korea ) , and the protein concentrations were determined using a bicinchoninic acid protein assay ( # 23227 , thermo fisher scientific , waltham , ma ) .
the proteins were separated using 10% sodium dodecyl sulfate polyacrylamide gel electrophoresis , followed by blotting onto nitrocellulose membranes , and probing with the antibodies against hoxa11 ( # sc-48542 , 1:500 dilution , santa cruz biotechnology , santa cruz , ca ) .
the blotted membranes were then incubated with the goat anti - rabbit igg secondary antibody for 1 hour .
subsequently , the membranes were incubated in an amersham ecl - prime solution ( # rpn2232 , ge healthcare life sciences , pittsburgh , pa ) in the dark for 1 minute and exposed under fluorchemhd2 ( cell biosciences , santa clara , ca ) for visualization . only the samples with a consistent result from repeated experiments were selected for analysis .
the densities of the bands were measured using free image analyzer software ( imagej v1.8x , national institutes of health , http://rsb.info.nih.gov/ij/ ) .
to knock down hoxa11 expression in cells , small interfering rna ( sirna ) experiments were performed using commercially available sequences targeting hoxa11 ( # sasi - hs01 - 00110410 , # sasi - hs01 - 00110413 , and # sasi - hs01 - 00110417 , sigma aldrich , st .
louis , mo ) as well as with the non - targeting control sirna ( # d-001610 - 01 - 05 , dharmacon , lafayette , co ) .
when the cells reached 70%-80% confluence , they were transfected with sirna under the most efficient transfection condition , as determined by the neon transfection system ( # mpk5000 , life technologies ) .
the cells were cultured in media without antibiotics to increase the sirna transfection efficiency for 24 hours .
the control and transfected cells were grown on 96-well plates at a density of 410 cells per well for 24 hours .
subsequently , the cells were either treated with tmz ( # alx-420 - 044-m100 , enzo life sciences , farmingdale , ny ) to a final concentration of 300 g / ml for 24 hours or irradiated with 4 mv x - rays from a linear accelerator ( clinac 4/100 , varian medical systems , palo alto , ca ) at a dose rate of 10.0 gy / min . for the combination treatment , the cells were irradiated first and then treated with tmz .
cell viability analysis was performed using a colorimetric cell counting kit-8 ( cck ; dojindo molecular technologies , kumamoto , japan ) .
the number of viable cells was quantified according to the manufacturer s instructions by reading the ultraviolet absorption spectra at 450 nm on a microplate 2 hours after adding 10 l of a cck solution per well .
for tissue sample analysis , the total rna was extracted from the tissue samples using the mirvana mirna isolation kit ( # am1560 , ambion , austin , tx ) for microarray analysis after quantification and qualification .
the total rna quality was determined using an agilent 2100 bioanalyzer ( agilent technologies , santa clara , ca ) .
the cut off rna integrity number for rna used in rna amplification was 7.0 or above .
the crna was produced using an illumina totalprep rna amplification kit ( # il1791 , ambion ) according to the provided protocol .
the crna was used for hybridization to a human ht12-v4 illumina beadchip gene expression array ( illumina , san diego , ca ) according to the manufacturer s protocol .
the arrays were scanned and the fluorescence signals were obtained using an illumina beadarray reader ( beadstation 500gxdw , illumina ) .
the signal obtained from the scanned beadchip was transformed to intensity raw data using genomesortudio software ( ver .
the raw data were normalized by applying a log2 transformation , quantile normalization , and gene and array centering .
2.14 , http://www.bioconductor.org ) . to determine the changes in gene expression before and after hoxa11 knockdown ,
the total rna extracted from the ln18 cells transduced with sihoxa11 or control sirna were analyzed by affymetrix genechip human gene 1.0st arrays ( affymetrix , santa clara , ca ) .
the rna was amplified and labeled using a genechip wt sense target labeling and control reagents kit ( affymetrix ) .
the cdna was synthesized , labeled , and hybridized to the genechip array according to the manufacturer 's protocol .
the genechips were washed and stained using the genechip fluidics station 450 ( affymetrix ) , and then scanned using a genechip scanner 3000 7 g ( affymetrix ) .
affymetrix expression console ver . 1.1 ( affymetrix ) was used to compare the group signals , and the data were logtransformed ( base 2 ) for parametric analysis .
the differentially expressed genes ( degs ) were identified by significance analysis of the microarrays method in the r package samr ( r 2.11.1 ) .
the data from the experiments were tested for their significance using an unpaired two - tailed student 's t test . an anova and student 's t test were used to identify the significant differences in cell death rates .
a p - value of 0.05 or lower was considered significant . for microarray analyses , the false discovery rates ( fdrs ) were calculated using three genepattern software modules ( http://www.broadinstitute.org/cancer/software/genepattern ; comparativemarkerselection ver .
the significantly regulated genes were subjected to functional gene classification using the david bioinformatics resources annotation tool ( ver .
the selected gene ids of the identified degs were entered into genemania software ( ver .
the relative changes in hox gene expression in five pairs of primary and recurrent gbm samples were assessed using microarray analysis ( fig .
1 ) . among the 39 hox genes , hoxa11 was the only gene that consistently showed a significant down - regulation in the recurrent samples ( p=0.046 ) .
the overall survival of a separate set of 20 gbm patients indicated significantly favorable prognoses in those with high hoxa11 expression compared to those with low hoxa11 protein expression ( survival , 3115.3 months with high hoxa11 expression vs. 187.3 months with low hoxa11 expression , p=0.03 ; expression status determined by western blot analysis ) ( fig .
therefore , the down - regulation of hoxa11 is associated with a poor prognosis in gbm patients . to confirm the effects of hoxa11 expression on the resistance to the current standard treatment protocol for gbm , three malignant glioma cell lines ( u251 , u373 , and ln18 ) were transduced with hoxa11 sirna to assess the cell viability .
the viable cell fractions were analyzed 72 hours after treatment with either single or combination applications of radiation treatment ( rt ) and tmz . a significant increase in the number of cells with hoxa11 suppression after
when hoxa11 was suppressed , the treatment resistance effect was more pronounced after treatment with a combination of rt and tmz ( p=0.022 for rt vs. rt / tmz and p=0.053 for tmz vs. rt / tmz ) . to identify the genes under the regulation of hoxa11 , the microarray expression profiling data of the control ln18 cells was compared with that of the hoxa11-silenced cells with hoxa11 sirna .
ln18 was chosen because it showed the most significant decrease in hoxa11 expression after sirna transduction among the three cell lines tested .
after normalization of the values and deg analysis , 11 up - regulated and 51 down - regulated genes that exhibited more than two - fold changes after hoxa11 suppression were identified ( fig . 4 , supplementary dataset ) .
the functional annotation tools within david bioinformatics resources ( http://david.abcc.ncifcrf.gov/home.jsp ) was then used for gene annotation enrichment analysis for the identified degs .
three gene ontology categories ( go:0040008 regulation of growth , go:0005739 mitochondrion , and go:0004157 dihydropyrimidinase activity ) were enriched significantly ( ease score < 0.05 ) in 11 genes ( ei24 , crim1 , mul1 , tgfbr2 , txnip , stxbp1 , elk3 , cox7a2 , nras , dpysl2 , and crmp1 ) among the deg set ( table 2 ) . for deeper insight into the hoxa11 regulatory mechanism , network analysis was performed using genemania software ( ver .
the network was constructed with the coexpression relationships , which revealed transforming growth factor , beta receptor 2 ( tgfbr2 ) , cysteine rich transmembrane bmp regulator 1 ( crim1 ) , thioredoxin interacting protein ( txnip ) , dihydropyrimidinase - like 2 ( dpysl2 ) , and collapsin response mediator protein 1 ( crmp1 ) genes to be the key hub regulators associated with hoxa11 suppression ( fig .
the relative changes in hox gene expression in five pairs of primary and recurrent gbm samples were assessed using microarray analysis ( fig .
1 ) . among the 39 hox genes , hoxa11 was the only gene that consistently showed a significant down - regulation in the recurrent samples ( p=0.046 ) .
the overall survival of a separate set of 20 gbm patients indicated significantly favorable prognoses in those with high hoxa11 expression compared to those with low hoxa11 protein expression ( survival , 3115.3 months with high hoxa11 expression vs. 187.3 months with low hoxa11 expression , p=0.03 ; expression status determined by western blot analysis ) ( fig .
therefore , the down - regulation of hoxa11 is associated with a poor prognosis in gbm patients .
to confirm the effects of hoxa11 expression on the resistance to the current standard treatment protocol for gbm , three malignant glioma cell lines ( u251 , u373 , and ln18 ) were transduced with hoxa11 sirna to assess the cell viability .
the viable cell fractions were analyzed 72 hours after treatment with either single or combination applications of radiation treatment ( rt ) and tmz . a significant increase in the number of cells with hoxa11 suppression after
when hoxa11 was suppressed , the treatment resistance effect was more pronounced after treatment with a combination of rt and tmz ( p=0.022 for rt vs. rt / tmz and p=0.053 for tmz vs. rt / tmz ) .
to identify the genes under the regulation of hoxa11 , the microarray expression profiling data of the control ln18 cells was compared with that of the hoxa11-silenced cells with hoxa11 sirna .
ln18 was chosen because it showed the most significant decrease in hoxa11 expression after sirna transduction among the three cell lines tested .
after normalization of the values and deg analysis , 11 up - regulated and 51 down - regulated genes that exhibited more than two - fold changes after hoxa11 suppression were identified ( fig . 4 , supplementary dataset ) .
the functional annotation tools within david bioinformatics resources ( http://david.abcc.ncifcrf.gov/home.jsp ) was then used for gene annotation enrichment analysis for the identified degs .
three gene ontology categories ( go:0040008 regulation of growth , go:0005739 mitochondrion , and go:0004157 dihydropyrimidinase activity ) were enriched significantly ( ease score < 0.05 ) in 11 genes ( ei24 , crim1 , mul1 , tgfbr2 , txnip , stxbp1 , elk3 , cox7a2 , nras , dpysl2 , and crmp1 ) among the deg set ( table 2 ) . for deeper insight into the hoxa11 regulatory mechanism , network analysis was performed using genemania software ( ver .
the network was constructed with the coexpression relationships , which revealed transforming growth factor , beta receptor 2 ( tgfbr2 ) , cysteine rich transmembrane bmp regulator 1 ( crim1 ) , thioredoxin interacting protein ( txnip ) , dihydropyrimidinase - like 2 ( dpysl2 ) , and collapsin response mediator protein 1 ( crmp1 ) genes to be the key hub regulators associated with hoxa11 suppression ( fig .
hox genes , which are a cluster of master regulators of embryogenesis , are expressed temporarily during the developmental phase in vertebrates , but they should be silenced in the adult central nervous system . accumulating
evidence of the aberrant expression of hox genes in cancers suggests that these genes have diverse roles in oncogenesis [ 2,3,21 - 26 ] .
in addition , a relationship between the hox genes and treatment resistance or prognosis in cancer has frequently been proposed .
moreover , there is evidence suggesting that the restored expression of tumor suppressor hox genes can attenuate the cancer progression in vitro and in vivo [ 29 - 31 ] .
experimental evidence of an association between hoxa10 and tmz resistance in gbm has been presented .
subsequent reports into the oncogenic role of hoxa10 in various cancers have been published [ 32 - 40 ] . on the other hand , based on the previous experimental data
it is suspected that hoxa11 acts as a tumor suppressor in opposition to hoxa10 , which prompted a further study of the function of hoxa11 in gbm .
the present study proposes a tumor suppressor function of hoxa11 in gbm based on the results from both in vitro experiments and human samples .
the role hoxa11 in diverse cancers has been reported [ 41 - 47 ] . in gastric cancer
, the epigenetic down - regulation of hoxa11 has been related to carcinogenesis , proliferation , migration , and invasion .
similarly , in lung and ovarian cancers , the down - regulation of hoxa11 was shown to be a poor prognostic factor . in gbm ,
the epigenetic down - regulation rate of hoxa11 was reported to be 51%-75% , and hoxa11 was one of the most frequently methylated genes in gbm [ 45 - 47 ] .
the methylation of hoxa11 was associated with older patient ages and poor survival in gbm .
in addition to the evidence of the epigenetic characteristics of hoxa11 as a prognostic marker , the present study provides direct evidence of the prognostic value of hoxa11 expression in gbm samples ( figs . 1 and 2 ) .
based on previous reports and the results in the present study , it is obvious that hoxa11 is a tumor suppressor in gbm and other cancers . treatment resistance induced by hoxa11 down - regulation , as detected by in vitro experiments in this study , is a mechanism contributing to a poor prognosis .
in addition , this study detected candidate mediators ( tgfbr2 , crim1 , txnip , dpysl2 , and crmp1 ) that may impart treatment resistance after hoxa11 suppression .
hoxa11 was reported to be a tumor suppressor gene that can sensitize a chemotherapeutic agent in ovarian cancer . on the other hand ,
there is little direct evidence of treatment resistance induced by hoxa11 suppression in other cancer types .
nevertheless , these results provide a promising basis for the development of hoxa11 applications that target chemo- or radio - sensitizers in gbm . among the five candidate mediators of hoxa11 suppression - induced oncologic effect ,
none have been reported to be associated with a hoxa11 regulatory mechanism . on the other hand ,
recently , it was suggested that decreased crmp1 expression in gbms harboring egfrviii positivity is responsible for promoting invasion .
moreover , those authors proposed the counter - activation of rac-1 after crmp1 suppression as a mechanistic hypothesis for the invasive phenotype .
other evidence regarding the role of hoxa11 in oncogenesis includes a report on the regulation of matrix metalloproteinase 2 expression , which can affect cancer cell migration and invasion .
overall , this study postulates an oncogenic pathway involving egfrviii , hoxa11 , crmp1 , and rac-1 in gbm , which will require further investigation .
the treatment resistance induced by the underexpression of hoxa11 can contribute to a poor prognosis in gbm .
further investigation will be needed to confirm the value of hoxa11 as a potential target for overcoming treatment resistance by developing chemo- or radio - sensitizers .
| ### Summary:
: purposehomeobox ( hox ) genes are essential developmental regulators that should normally be in the silenced state in an adult brain .
the aberrant expression of hox genes has been associated with the prognosis of many cancer types , including glioblastoma ( gbm ) .
this study examined the identity and role of hox genes affecting gbm prognosis and treatment resistance.materials and methodsthe full series of hox genes of five pairs of initial and recurrent human gbm samples were screened by microarray analysis to determine the most plausible candidate responsible for gbm prognosis .
another 20 newly diagnosed gbm samples were used for prognostic validation . in vitro experiments
were performed to confirm the role of hox in treatment resistance .
mediators involved in hox gene regulation were searched using differentially expressed gene analysis , gene set enrichment tests , and network analysis.resultsthe underexpression of hoxa11 was identified as a consistent signature for a poor prognosis among the hox genes .
the overall survival of the gbm patients indicated a significantly favorable prognosis in patients with high hoxa11 expression ( 3115.3 months ) compared to the prognoses in thosewith low hoxa11 expression ( 187.3 months , p=0.03 ) . when hoxa11 was suppressed in the gbm cell lines , the anticancer effect of radiotherapy and/or temozolomide declined .
in addition , five candidate mediators ( tgfbr2 , crim1 , txnip , dpysl2 , and crmp1 ) that may confer an oncologic effect after hoxa11 suppression were identified.conclusionthe treatment resistance induced by the underexpression of hoxa11 can contribute to a poor prognosis in gbm .
further investigation will be needed to confirm the value of hoxa11 as a potential target for overcoming the treatment resistance by developing chemo- or radiosensitizers . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the term aluminium lung was first used by goralewski in the 1940s1 . in the current literature , there
are no arguments about the existence of lung damage from inhalation exposure to dust
containing aluminium particles or compounds , the so - called aluminosis . pulmonary aluminosis
is defined as pneumoconiosis caused by the presence of dust containing aluminium in the lung
tissue2 . the condition is
clinically significant in that it may result in pulmonary fibrosis .
there were reports of
cases of death even after few years from the onset of symptoms , e.g. after 3 or
5 yr3 , 4 .
radiographic findings may vary considerably , showing nodular or slightly irregular
opacities that may merge into more prominent formations , most frequently in the upper lung
fields6 , 7 , 10 , 11 .
some authors also reported their distribution in the lower
lung fields10 , 11 or , less frequently , a diffuse
micronodular pattern4 ,
12 , as seen in our
patient .
severe
pulmonary fibrosis with honeycombing was described5 , 7 ,
12 , 14 .
his personal and family history was
unremarkable , the only exception being pulmonary sarcoidosis of his cousin .
the first symptoms of the disease were noticed in september 2006 and included severe
exertional dyspnoea with non - productive cough .
the patient was afebrile , with a bmi of
26.64 . otherwise , physical examination including lung auscultation showed no abnormalities .
at that time ,
a plain chest radiograph revealed numerous dispersed micronodules with
bilateral hilar enlargement ( fig .
1.patients plain chest radiograph with numerous dispersed micronodules and bilateral
hilar enlargement . ) .
gallium
scintigraphy showed bilateral hilar lymph node enlargement and diffuse uptake of the
radiopharmaceutical in both lungs .
an hrct scan of the lungs showed diffuse small foci and
enlarged intrathoracic lymph nodes .
as a part of the differential diagnosis of dyspnoea with
non - productive cough , video - assisted thoracoscopic surgery ( vats ) was performed and lung
biopsy specimens were obtained in october 2006 . the surgically excised material was fixed in
10% formalin and embedded in paraffin .
histological sections of 34 m were stained with
haematoxylin and eosin using the pas ( periodic acid schiff ) method , as described by van
gieson , gomori and perl .
immunohistochemistry tests were performed using a two - step indirect
method with antibodies against s-100 protein , cd68 and cd1a .
histologically , an exudative
and proliferative process was described in the lung tissue , with nodular histiocytic
infiltrates . the final diagnosis made at a local respiratory clinic was stage ii to iii
sarcoidosis .
systemic corticosteroids were administered for 10 months , until august 2007 ,
but with no therapeutic effect .
therefore , the histological preparation from the original vats biopsy was reassessed in
november 2007 at the university hospital .
the lung infiltrates were histiocytic and
non - granulomatous , different from well formed granulomas in sarcoidosis .
no microcrystalline
particles were found and immunohistochemistry ( cd68 positive , s-100 protein and cd1a
negative ) was not consistent with langerhans cell histiocytosis .
peribronchial histiocytic and non - granulomatous infiltrates in
collapsed lung tissue in a more detail ( haematoxylin and eosin stain , 200
magnification ) . ) .
without detailed knowledge of
occupational history , the histopathologist established the diagnosis of non - langerhans cell
histiocytosis suggestive of erdheim - chester disease .
perivascular and peribronchial histiocytic and non - granulomatous infiltrates in
collapsed lung tissue in a more detail ( haematoxylin and eosin stain , 200
magnification ) .
although
erdheim - chester disease is a condition characterized by both skeletal and extraskeletal
lesions , no typical skeletal changes were seen in a december 2007 pet / ct scan .
bone lesions
were not even confirmed by three - phase bone scintigraphy a month later .
both pet / ct and hrct
scans were only suggestive of multiple diffuse micronodules in the lungs . after another year of the above therapy
, the patient s clinical condition remained
unchanged , with persisting exertional dyspnoea and non - productive cough .
small disseminated
lesions seen on a chest radiograph were unchanged , both pulmonary mechanics and diffusing
capacity were normal .
no significant abnormalities were found by biochemistry , immunology
and haematology tests . given the poor response to therapy and regarding the fact that
erdheim - chester disease was not clinically confirmed , the histological sample was assessed
for the third time in january 2009 , using an electron microscope .
the material for electron
microscopy was fixed with glutaraldehyde and osmium tetroxide and embedded in epon .
elemental analysis of
the sample was performed with the edax system for x - ray structural analysis .
it revealed in
particular the presence of aluminium ( later also iron pigments and their silicon compounds
including elements from the above fixing agents ) .
the basic histiocytic morphology of the lung involvement and results of elemental analysis
corresponded with those in pneumoconiosis ( fig .
3.electron microscope image of histiocytes with nuclei and ample , in part vacuolated
cytoplasm with depositions of electron - dense granular material .
. electron microscope image of histiocytes with nuclei and ample , in part vacuolated
cytoplasm with depositions of electron - dense granular material .
a more detailed occupational history was taken which revealed that the patient had
approximately 10-yr occupational exposure to aluminium - containing dust . in his last job
between 2000 and 2006 , he worked as an aviation mechanic , grinding and polishing aluminium
sheets .
after the diagnosis of aluminosis was suspected , in order to classify the condition as an
occupational disease , occupational exposure had to be objectively verified at the patient s
workplace by industrial hygiene specialists .
but there were several factors which made this hygienic assessment more difficult : the
patient s employer did not measure relevant risk factors associated with performing the job
of an aviation mechanic . then the factory changed the owner and at the time when hygienic
assessment was performed , working conditions and technologies were different as well .
because of that the exact measurement of the airborne concentrations of aluminium at the
workplace could not be accomplished . however , working conditions and time proportion of
particular working operations were specified on the basis of the information obtained from
patient s former factory supervisors and material specifications of the used aluminium
sheets .
it was found that in his late job of an aviation mechanic , the patient was exposed to fine
aluminium dust .
this was the most significant and massive exposure which resulted mainly
from machine grinding of aluminium materials ( sheets containing as much as 92% of aluminium )
and their polishing with a hand - held drill and angle grinder .
an extremely dusty seasonal work was the so - called
airplane refurbishment , with sheet grinding including removal of anodic films accounting for
up to 80% of the working time .
the place was only
naturally ventilated through windows and gates , with dust constantly raised .
personal
protective equipment was inadequate as simple cloth dust masks could not sufficiently
protect from exposure to fine aluminium dust .
thus , according to the industrial hygiene specialists statement , conditions in the
patient s workplace met the criteria for the development of an occupational disease .
later , approximately 5 yr after the exposure was discontinued , increased aluminium
concentration in the patient s serum was also confirmed , reaching 656 nmol / l ( reference
range , 100400 nmol / l ) .
gradual exclusion of previous suspected diagnoses ( sarcoidosis , erdheim - chester disease ) , a
lack of response to therapy , the patient s occupational history and especially the
histological electron microscopy finding , together with increased serum aluminium level led
to the establishment of a diagnosis of pulmonary aluminosis . in 2011 , the diagnosis was
recognized and the patient was compensated for an occupational disease .
the presented case documents differential diagnostic assessment of exertional dyspnoea and
non - productive cough with radiographically detected multiple dispersed micronodules in the
lungs .
apart from histological diagnosis using electron microscopy with elemental analysis
of tissue , the key role was played by a detailed occupational history objectively verified
by hygiene assessment and confirmation of occupational exposure to significant amounts of
fine aluminium dust . as early as in 1936 , the effect of aluminium - containing dust inhalation on human health was
studied in great britain . at that time , however , the relationship between
aluminium - containing dust inhalation and pulmonary fibrosis was not found15 .
the first cases of lung damage
from exposure during aluminium processing were reported in the 1930s in germany . in 1934 ,
baader reported the first case ever of pulmonary fibrosis associated with the above
exposure , as mentioned in a 1938 study by doese16 .
then , in the 1940s , damage to the lungs from
aluminium - containing dust inhalation was extensively studied by goralewski2 . in 1960 , koelsch reported that
between 1943 and 1960 , twenty - seven cases of pulmonary aluminosis were recognized and
compensated in germany14 ,
18 .
moreover , in the 1940s , thirty - five cases of pulmonary fibrosis were reported among 344
canadian aluminium potroom workers with exposure in the manufacture of alumina abrasive .
traditionally , the highest risk with respect to potential lung damage is associated with
processes in bauxite smelting , the use of fine aluminium powder in the manufacture of
explosives , and aluminium welding8 .
some studies reported occasional cases of aluminosis from
grinding and polishing of aluminium materials , similar to the presented case5 , 8 , 9 . in 1986 ,
de vuyst and colleagues published a case of a metal polisher doing his job for
24 yr , using abrasives to polish aluminium materials mainly in the second half of his
exposure and developing a severe form of interstitial lung fibrosis with honeycombing and
emphysema8 .
necropsy
findings revealed a diffuse interstitial fibrosis with increased collagen and moderate
infiltration with mononuclear cells .
electron microscopy revealed alveolar and septal
macrophages exhibiting phagolysosomes with electron - dense content .
elemental analysis of
bal , lung tissue and lymph node tissue samples confirmed aluminium as the most abundant
mineral8 , similarly to our
case .
more recently , kraus et al . in their 2006 article reported lung changes in
workers in two german plants producing aluminium powder who had been exposed to a mixture of
aluminium particles and various lubricants .
the changes were detected by hrct in 15 out of
62 workers , including 2 polishers9 . as summarized by krewski et al .
histological findings in aluminosis are
most typical for the presence of pulmonary fibrosis of various extent and in many cases
confirmed presence of particles containing aluminium5 .
there have been extensive discussions in the literature regarding the pathophysiological
basis of aluminosis and many authors asked what is behind the ability of aluminium to cause
lung tissue fibrosis .
a range of potential influencing pathophysiological and environmental
factors were studied : existence of fibrous particles of alpha aluminium oxide4 , the role of aluminium oxides and
their low temperature transitional forms ( such as gamma aluminium oxide)4 , 10 or the impact of processing aluminium powder , namely the
role of additives and lubricants17 .
other authors suppose that an important and dangerous role
is played by inhalation of fine dust with respirable aluminium particles sized 0.55
m7 .
some of
these hypotheses were not supported , several authors concluded that the previous suggestions
relating aluminium - induced fibrosis to the presence of gamma aluminium oxide had not been
correct4 , 11 .
however , the pathophysiology of pulmonary aluminosis has not been fully explained as
yet .
since the industrial
importance and use of aluminium continue to rise , lung damage from exposure to aluminium
should not be overlooked , from the perspective of both possible diagnostic considerations
and prevention .
it is therefore desirable to monitor and minimize exposure to respirable
aluminium particles and to try to detect early stages of the disease as well . | ### Summary:
: the authors present a case of occupational lung damage from exposure to dust
containing aluminium .
the first detected objective pathological finding was that of
dispersed micronodules in the lungs seen in a chest radiograph .
the final diagnosis of
pulmonary aluminosis was established after three years of gradual exclusion of other
interstitial lung diseases .
the diagnosis was supported by the occupational history
confirmed by hygiene assessment of the patient s workplace and especially by histological
examination with elemental analysis of the lung tissue .
the possibility of development of
this rare condition should not be underestimated in workers at high - risk jobs . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: type 1 diabetes ( t1d ) is a chronic disease manifested by the loss of functional insulin producing cells of pancreatic islets , caused by islet infiltrating self - reactive cd4 and cd8 t cells that mediate -cell destruction .
many of the immunological aspects of human t1d are mimicked by the nonobese diabetic ( nod ) mouse model , which shows islet infiltration and destructive autoimmune insulitis as early as four weeks of age and spontaneously progresses to overt diabetes in the adult .
observations in mice and humans have demonstrated that cd4cd25 regulatory t ( treg ) cells expressing the forkhead box transcription factor foxp3 play an indispensable role in the maintenance of immune homeostasis by regulating inflammatory responses against invading pathogens and preventing destructive autoimmunity [ 36 ] .
a particularly striking example of foxp3 treg cell function that restrains destructive tissue - specific autoimmune responses is the observation that acute ablation of treg cells in adult nod mice carrying a pancreatic cell - reactive t cell receptor ( tcr ) as a transgene unleashes overt autoimmune diabetes within days ( see section 4.3 ) . given their nonredundant function in maintaining immune homeostasis , it is not surprising that foxp3 treg cells have attracted considerable attention as particularly promising gain - of - function targets in clinical settings of unwanted immune responses , such as t1d . here
, we provide an overview of mouse models for t1d that , in our view , appear particularly suitable to study various aspects of foxp3 treg cell - mediated control of cell autoimmunity , ranging from classical diabetes models adapted to the functional analysis of treg cells to novel genetic tools for treg cell depletion in nod mice .
double - transgenic mice that coexpress model antigens ( such as ovalbumin , lcmv glycoprotein , or influenza hemagglutinin ; ha ) in pancreatic cells together with tcrs reactive to the respective cell neo - self - antigen ( either mhc class i- or class ii - restricted ) spontaneously develop autoimmune diabetes , recapitulating some aspects of the spontaneous nod model , albeit with faster kinetics . as an example , transgenic expression of an ha - reactive tcr on cd4 ( tcr - ha107119 ) [ 9 , 10 ] or cd8 ( cl4-ha512520 ) t cells promotes spontaneous diabetes development in mice that additionally express ha under control of the rat insulin promoter ( rip - ha ) .
potential limitations of the rip - ha model , many of which are shared between the various double - transgenic diabetes models , have been discussed in detail elsewhere .
nevertheless , tcr - ha rip - ha mice offer some advantages that appear particularly relevant in the context of mechanistic studies on antigen - specific tolerance induction .
while limiting cell pathogenicity to a single , well - defined neo - self - protein , and in contrast to many other transgenic tcrs ( e.g. , do11.10 ) , the tcr - ha is expressed only on a fraction of cd4 t cells ( ranging from 5% to 20% in different lymphoid tissues ) that coexist with polyclonal populations of tcr - ha cd4 t cells expressing endogenous tcr gene rearrangements . in the tcr - ha
rip - ha model , selective delivery of agonist ligand to steady - state dec-205 dcs has been shown to interfere with the development of autoimmune diabetes , probably due to the extrathymic induction of antigen - specific foxp3 treg cells from initially nave foxp3tcr - ha t cells [ 16 , 17 ] .
however , it appears desirable that findings observed in double - transgenic models of spontaneous autoimmune diabetes will subsequently be extended to the nontransgenic nod model . in immunodeficient ( rag , nude )
rip - ha recipient mice , adoptive transfer of nave cd4tcr - ha t cells ( i.e. , without prior t cell activation in vitro ) from tcr - ha donor mice induces autoimmune diabetes within 1 - 2 weeks [ 10 , 14 , 18 ] . in immunocompetent recipient mice ,
nave cd4tcr - ha t cell transfer ( figure 1(a ) ) fails to induce overt diabetes ( figure 1(c ) ) , perhaps due to extrathymic induction of a foxp3 treg cell phenotype in a significant proportion of initially foxp3 t cells , upon recognition of the cognate antigen on antigen - presenting cells residing in peripheral lymphoid tissues ( figure 1(b ) ) .
notably , initially nave cd8cl4 and cd4tcr - ha ( figure 1(c ) ) t cells , which had been preactivated in vitro as previously described , can promote autoimmune diabetes development shortly after injection into immunocompetent recipient mice .
it is important to emphasize that kinetics and efficiency of diabetes induction critically depend on suitable culture conditions for preactivation .
pgk - ha mice represent a convenient source of antigen - specific foxp3 treg cells , as expression of ha under control of the phosphoglycerate kinase promoter ( pgk - ha ) results in peripheral accumulation of intrathymically induced foxp3tcr - ha treg cells .
foxp3tcr - ha t regulatory 1 cells with potent suppressor capacity can be readily isolated from peripheral lymphoid tissues of tcr - ha mice that coexpress ha under the control of the ig- promoter .
overall , the rip - ha model offers unique opportunities to study mechanisms of antigen - specific suppression of cell autoimmunity , employing cotransfer of tcr - ha treg cells , either with a foxp3 or foxp3 phenotype , together with pathogenic t effector cells ( cd4tcr - ha or cd8cl4 ) .
cd4 t cells expressing the bdc2.5 tcr as a transgene , which is reactive to islet cells in the context of mhc class ii ag7 molecules , are highly diabetogenic in nod mice [ 24 , 25 ] .
while agonistic mimotope peptides that stimulate bdc2.5 t cells at nanomolar concentrations had been described some years ago , chromogranin a has only recently been proposed to represent the natural self - antigen responsible for pancreatic cell pathogenicity of bdc2.5 t cells .
nave bdc2.5 t cells , facs purified ( figure 2(a ) ) from peripheral lymphoid tissues of immunocompetent nod.bdc2.5 mice with foxp3-dependent gfp expression ( see section 4.3 ) and adoptively transferred into either tcr- or rag1 ( figure 2(b ) ) nod mice , undergo lymphopenia - driven proliferation , resulting in the acquisition of a foxp3 treg cell phenotype in a significant proportion of initially foxp3 t cells [ 2931 ] .
nevertheless , without prior t cell activation in vitro , adoptive transfer of 5 10 nave bdc2.5 t cells consistently induces autoimmune diabetes in lymphopenic nod mice within 13.0 1.2 days , as revealed by high blood glucose concentrations ( figure 2(c ) ) . in this adoptive transfer model , autoimmune diabetes onset
can be further accelerated by tcr prestimulation in vitro and injection of increasing numbers of bdc2.5 t cells ( figure 2(c ) ) .
in fact , adoptive transfer of in vitro activated bdc2.5 t cells into neonatal or immunodeficient ( scid , tcr- , rag1 ) nod recipient mice is commonly used as a standard protocol for the induction of autoimmune - mediated pancreatic islet inflammation . in contrast to t helper ( th )
2 and th17 cells that had been generated from bdc2.5 t cells in vitro , th1-polarized bdc2.5 t cells efficiently induce aggressive autoimmune diabetes upon injection into neonatal nod mice , whereas th17 bdc2.5 cells have been reported to promote rapid onset of diabetes in adult nod.scid mice .
in addition to providing diabetogenic cd4bdc2.5 t effector cells , nod.bdc2.5 mice with foxp3-dependent gfp expression [ 28 , 3437 ] represent a convenient source of foxp3 treg cells with the same antigen specificity , which can be readily facs purified ( v4cd4cd25gfp ) from cd25 bead enriched single cell suspensions of peripheral lymphoid donor tissues ( figure 3(a ) ) .
importantly , cotransfer of as few as 5 10 foxp3bdc2.5 treg cells is sufficient to mediate long - term autoimmune protection of nod.rag1 mice that additionally received 5 10 diabetogenic nave bdc2.5 t cells ( figure 3(b ) ) .
besides studies on the suppressor function of foxp3bdc2.5 treg cell populations naturally developing in nod.bdc2.5 mice , the adoptive bdc2.5 t cell transfer model provides the opportunity to assess the suppressive capacity of foxp3 treg cells that had been artificially generated from initially foxp3bdc2.5 t cells in experimental settings of extrathymic treg cell induction , for example , by retrovirus - mediated ectopic expression of foxp3 ( figure 3(c ) ) .
note that , as compared to the adoptive transfer of nave bdc2.5 t cells alone ( figure 3(b ) ) , cotransfer of [ empty]-ires - yfp bdc2.5 t cells substantially accelerates diabetes due to t cell prestimulation in vitro for retrovirus infection ( figure 3(c ) ) . in immunocompetent nod mice , the in vivo application of in vitro
expanded foxp3bdc2.5 treg cells [ 38 , 39 ] , as well as foxp3bdc2.5 treg cells , generated in vitro either by ectopic expression of foxp3 or tgf--mediated induction of foxp3 expression , can be effective in prevention or even reversal of spontaneously developing diabetes .
unfractionated splenocytes from diabetic , non - tcr transgenic nod donor mice can induce autoimmune diabetes within 3 weeks after injection into immunodeficient nod mice , such as nod.rag1 mice ( figure 3(d ) ) or irradiated nod mice .
although the relative contribution of cd4 and cd8 t cells had remained controversial in previous studies [ 42 , 43 ] , more recent observations in nod.scid mice using highly purified t cell populations revealed that the development of autoimmune diabetes in this adoptive transfer model requires both cd4 and cd8 t cells .
cotransfer of polyclonal foxp3 treg cells , either purified populations or contained in unfractionated total cell populations , can be employed to assess their suppressive capacity in the context of autoimmune diabetes .
after tolerogenic dec-205 dendritic cell vaccination to promote proinsulin - reactive foxp3 treg cell activity , cotransfer of total spleen cells from autoimmune protected nod donors can delay the onset of diabetogenic splenocyte - mediated diabetes in nod.rag1 recipients ( figure 3(d ) ) .
abrogated treg cell function has been actively debated as a putative mechanism underlying various autoimmune disorders in humans .
the important role of foxp3 treg cells in protection from autoimmune diabetes is highlighted by the notion that t1d represents a major component of the ipex ( immune dysfunction , polyendocrinopathy , enteropathy , x - linked ) syndrome [ 4648 ] that affects humans with abrogated treg cell function due to mutations in the foxp3 gene [ 4951 ] . in mice ,
spontaneous or gene - targeted foxp3 deficiency leads to death by 3 - 4 weeks of age due to the development of a fatal multiorgan autoimmune syndrome that recapitulates many clinical features of the human ipex syndrome .
notably , the manifestation of autoimmune diabetes in foxp3-deficient mice on non - autoimmune - prone genetic backgrounds has not been reported thus far . moreover ,
foxp3-deficient mice on the diabetes - prone nod background develop exocrine pancreatitis and peri - insulitis , but do not manifest invasive insulitis and diabetes .
several nonmutually exclusive mechanisms may account for the absence of overt diabetes in foxp3-deficient mice , which includes premature death and altered t cell repertoire selection due to severe defects in thymic t cell development . in any case , this striking difference to human ipex patients regarding the manifestation of autoimmune diabetes limits the exploitation of mice with constitutive genetic foxp3 deficiency and concomitant absence of functional treg cells in studies on pancreatic cell autoimmunity . to examine
the contribution of foxp3 treg cells in the control of pancreatic cell autoimmunity , administration of anti - cd25 mabs has been widely used as a loss - of - function approach , with the overwhelming majority of studies employing the clone pc61 ( rather than 7d4 ) . whether abrogation of suppressor activity upon in vivo administration of anti - cd25 mabs can be attributed to the functional inactivation or the actual physical elimination ( deletion ) of cd25-expressing foxp3 treg cells has been controversially discussed [ 5658 ] . in otherwise nonmanipulated nod mice , single dose or repeated injection of the anti - cd25 mab pc61
can significantly accelerate the spontaneous development of autoimmune diabetes in adolescent but not adult females .
in experimental settings of tolerogenic regimens that result in long - term protection of nod mice from autoimmune cell destruction , anti - cd25 mabs have been employed as an approach to address the relative contribution of cd25 treg cells in tolerance induction , with pc61 administration resulting either in the rapid precipitation of overt diabetes [ 59 , 6163 ] or the failure to break established cell tolerance and maintenance of normoglycemia [ 6466 ] .
however , interpretation of results from such experiments is hampered by the fact that cd25 expression is not exclusive to foxp3 treg cells .
in fact , pc61 administration to adult nod mice has also been reported to delay diabetes onset , perhaps due to its negative impact on activated cd4 and cd8 t effector cells with upregulated cd25 expression .
additionally , it appears important to emphasize that anti - cd25 treatment with the aim to interfere with treg cell function , either by deletion or functional inactivation , will inevitably spare foxp3 treg cells with a cd25 phenotype .
consistently , anti - cd25 treatment protocols preserve significant numbers of foxp3 cells [ 5658 , 67 , 68 ] .
foxp3-dependent expression of the human diphtheria toxin ( dt ) receptor as a transgene , either from an internal ribosome entry site ( ires ) downstream of the foxp3coding region or from a foxp3 bacterial artificial chromosome ( bac ) ( termed depletion of regulatory t cell mice , dereg ; ) , provides an opportunity for specific and temporally controlled deletion of foxp3 treg cells in mice on non - autoimmune - prone genetic backgrounds . in both mouse models ,
foxp3 treg cell depletion by the in vivo administration of dt promotes the development of autoimmune disorders , albeit with differences in the severity of autoimmune symptoms [ 36 , 69 ] . on the nod genetic background , two independent mouse lines with dt receptor expression selectively in foxp3 treg cells
have been generated . while feuerer et al . established a novel foxp3 bac transgenic line employing nod embryos , we generated nod.foxp3 mice by backcrossing the bac - foxp3 transgene of the well - characterized dereg mouse model [ 36 , 7073 ] onto the nod / lt background ( figure 4 ) .
transgenic expression of the bdc2.5 tcr efficiently prevents the development of spontaneous autoimmune diabetes in immunocompetent nod females but dramatically accelerates diabetes progression in immunodeficient nod mice , such as nod.tcr- or nod.rag1 mice , as well as in nod.foxp3 mice .
acute ablation of foxp3 treg cells ( figure 4(a ) ) can lead to transiently increased blood glucose concentration in some adult nod.foxp3 females , but fails to consistently promote overt diabetes ( figure 4(b ) ) . in nod.foxp3 bdc2.5 females ,
foxp3 treg cell ablation triggers autoimmune cell destruction within 8 days after initiation of dt administration ( figure 4(b ) ) .
notably , and in contrast to the spontaneous nod model , the nod.foxp3 bdc2.5 model additionally allows the induction of autoimmune diabetes in male mice , with similar efficiency and kinetics as compared to females ( figure 4(c ) ) . | ### Summary:
: studies on human type 1 diabetes ( t1d ) are facilitated by the availability of animal models such as nonobese diabetic ( nod ) mice that spontaneously develop autoimmune diabetes , as well as a variety of genetically engineered mouse models with reduced genetic and pathogenic complexity , as compared to the spontaneous nod model . in recent years , increasing evidence has implicated cd4+cd25 + regulatory t ( treg ) cells expressing the transcription factor foxp3 in both the breakdown of self - tolerance and the restoration of immune homeostasis in t1d . in this paper , we provide an overview of currently available mouse models to study the role of foxp3 + treg cells in the control of destructive cell autoimmunity , including a novel nod model that allows specific and temporally controlled deletion of foxp3 + treg cells . |
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: several key events in the multistep process of neoplastic transformation of rat tracheal epithelium ( rte ) are described . whether tracheal epithelium is exposed in vivo to carcinogenic agents or whether primary tracheal epithelial cells are exposed in vitro to carcinogens , initiated stem cells
can be detected soon after the exposure by their ability to grow under selective conditions in culture .
these initiated stem cells differ fundamentally from normal stem cells in their response to factors normally constraining proliferation and self - renewal .
thus , disruption of inhibitory control mechanisms of stem cell replication appears to be the first event in rte cell transformation .
while the probability of self - renewal ( psr ) is clearly increased in initiated stem cells , most of the descendants derived from such stem cells differentiate and become terminal and do not express transformed characteristics .
progression from the first to the second stage of rte cell transformation , the stage of the immortal growth variant ( igv ) , is characterized by loss of responsiveness to the growth - restraining effects of retinoic acid . in the third stage of neoplastic transformation , the stage during which neoplastic growth variants ( ngv ) appear , a growth factor receptor gene is inappropriately expressed in some of the transformants .
thus , it appears that loss of growth - restraining mechanisms may be an early event , and activation of a growth stimulatory mechanism a late event , in neoplastic transformation of rte cells.imagesfigure 3.figure 12.figure 13 . |
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: body fluids are widely used in laboratory diagnosis . however , the process of obtaining them for research is accompanied by certain difficulties ( the introduction in the internal environment of the organism , tissue damage , compliance with special temporary algorithms which are not always physiological ) . in recent years
, the first steps were taken in the study of manifestations of various diseases on the structural organization of biological fluids [ 37 ] .
the structures of the investigated fluids are obtained via the phasic transfer from liquid to solid state through dehydration .
the results of experimental studies demonstrated that the information contained in the liquid phase at the molecular level in the dehydrating process is transferred at macroscopic level having different structures that become visible to the researcher .
the research of the self - organization processes of various physiological and pathological liquid media elucidated the primary importance of the organic components present in biological fluids even in a small amount ( from 0.01 microns to 100
the structures separation into organic and inorganic compounds is carried out by the dehydration method , by applying the biological liquid onto a transparent surface in the form of drops , and then dehydrated under specific conditions .
the volume of the droplet is determined by the ratio of the specific gravity of the liquid and its surface tension forces . according to theoretical concepts in biological fluid dehydration , specific mechanisms interact ,
the term facies refers to what is left from a drop of saliva , after drying out .
a graphical representation of the action of these mechanisms provides the scheme of the biological liquid droplet ( located on a horizontal plane ) in sagittal section , developed by tarasevici and aiupova ( 2003 ) ( fig .
the authors noted that the evaporation of the liquid does not occur uniformly over the entire open area of the droplet . due to the fact that the hemisphere has a different thickness in the central area as opposed to the peripheral area , the evaporation of the analyzed water droplet
, the concentration of the dissolved substance changes non - uniformly , thus particularly in the peripheral area ( which is of reduced thickness ) is increased more rapidly than in the central zone ( maximum thickness ) of the droplet . in such processes
because the power of osmotic forces considerably exceeds the oncotic ones , the salts migrate to the centre of the droplet , to the low concentration of dissolved substances . in the central area ,
the proteins and other dissolved substances with high molecular weight yield water and are shifted to the periphery of the droplet . as a result ,
the marginal amorphous zone of the dehydrated droplet , is presented by structures of organic origin , while the central crystallized one by salts .
thus , a shift of unstable structures is produced , rather dynamically at the molecular level in stable macrostructures of solid phase . according to the research of annarelli et al .
( 2001 ) , the central zone is called the crystallized structures zone , and the peripheral one - amorphous area .
peripheral width area ratio of the diameter of the droplet is used for the determination of protein contents in biological fluids .
therefore , taking into account the concept of classical crystallography , the early diagnosis of dental and systemic diseases , the method of crystallographic research of one of the most accessible biological liquid , i.e. oral liquid , was proposed .
oral liquid is a very well organized specific biological environment , with unique , universal properties is a dynamic environment , reflecting any changes in the body , including pathological processes . over the past decades ,
the first steps in studying the manifestations of various diseases in the structural organization of the oral liquid have been made [ 1316 ] .
the first investigations of crystalograms have revealed that after oral liquid droplets dehydration on the glass slide a sediment remains , its microcrystalline structure is dependent on the state of health of the oral cavity and the entire body .
the results of the study of outlined microcrystalization types characterize the ability of the saliva remineralization .
the optical properties of the crystals vary significantly depending on exo- and endogenous factors , this phenomenon being applied in the research , for diagnostic purposes .
the morphological image blurring or changing oral liquid is an indicator of qualitative and quantitative disorders of salivary proteins , mucins , being one of the earliest markers of pathological processes that occur in the body and can be used to detect diseases at the premorbid stage and to apply efficiently the preventive measures and minimally invasive treatment .
the structural features of microcrystalograms ( mcg ) are determined by the balance of organic mineral components and physicochemical properties of oral liquid .
the use of oral liquid in the health study can be justified by many arguments :
physicochemical properties of the oral liquid can be used as a marker for pathological changes not only in the salivary glands and oral cavity , but also in other organs and systems of human body [ 4,5,8,11,1721 ] .
oral liquid composition reflects the psycho - emotional state , the intensity of metabolism , severity of inflammatory processes , structural and functional properties of enamel and its resistance to caries attack .
a disorder in the contents of saliva and salivary secretion rate was noted in case of cardiovascular diseases .
changing the shape of the crystals is a consequence of the modification of the physicochemical properties of saliva .
changes in the composition of the saliva can be related not only to the presence of inflammatory processes and diseases ( acute and chronic ) , but also to the administration of drugs .structural peculiarities studies of oral liquid in the health study is promising due to the invasive method for obtaining biological material and simple application.the research method of oral fluid crytalogenesis by dehydration obtaining microcrystalograms ( mcg ) does not disturb the contents of the test sample and provides an overview of the state of the whole body .
physicochemical properties of the oral liquid can be used as a marker for pathological changes not only in the salivary glands and oral cavity , but also in other organs and systems of human body [ 4,5,8,11,1721 ] .
oral liquid composition reflects the psycho - emotional state , the intensity of metabolism , severity of inflammatory processes , structural and functional properties of enamel and its resistance to caries attack .
a disorder in the contents of saliva and salivary secretion rate was noted in case of cardiovascular diseases . changing the shape of the crystals is a consequence of the modification of the physicochemical properties of saliva .
changes in the composition of the saliva can be related not only to the presence of inflammatory processes and diseases ( acute and chronic ) , but also to the administration of drugs .
structural peculiarities studies of oral liquid in the health study is promising due to the invasive method for obtaining biological material and simple application .
the research method of oral fluid crytalogenesis by dehydration obtaining microcrystalograms ( mcg ) does not disturb the contents of the test sample and provides an overview of the state of the whole body .
thus , the main advantages of oral fluid microcrystalograms oral liquid mcg are non - invasiveness , simplicity of implementation and availability of substrate sampling study providing new insights into clinical trials .
therefore , the study of crytalogenesis oral fluid dynamics is up to date to produce precise quantitative assessment parameters of fractal structures and further standardization of analysis process of oral liquid mcg .
the purpose of the paper consisted in the study of the oral liquid microcrystalization peculiarities in children with gerd .
to achieve the objective 54 children were clinically examined : 27 ( 50% ) children with gerd were the research group and 27 ( 50% ) healthy children
control group . selecting children s groups was randomly , the groups had the same age and sex .
the two groups were matched regarding gender , age , residence environment and social - economic conditions .
we performed the clinical examination of the patients , including the assessment of the dental caries prevalence by estimating the dmft index .
the assessment of the erosive wear was performed on the palatine / lingual sides , on the vestibular and incisal / occlusal sides , noting down a single value for each sextant , corresponding to the dental side having the greatest erosion degree .
the final score of the bewe index was obtained by adding up the values of all sextants based on which the erosive wear was calculated . in addition , we assessed the enamel resistance to acids , using the enamel resistance test following the method proposed by okushko , 2011 , the ph of saliva , salivary flow rate , the buffering capacity of saliva and the remineralization potential of saliva , assessed by estimating the remineralization speed of saliva using the method elaborated by leontiev et al . 2007 . in this study , we performed a comparative analysis of the crystallographic modifications of the of in children with and without decay according to the method developed by shatohina et al , 2006 .
oral liquid was collected with a sterile pipette in the amount of 0.2 to 0.3 ml of the oral cavity floor .
then , on a glass slide , pre - treated with alcohol and ether , three drops of oral liquid were applied .
the dehydration of the of product drops was produced into the unit at t=37c , protected from dust .
micropreparations were examined under scanning electron microscope vega ts 5130 mm tescan . using mcg and oral liquid research methods the central and peripheral areas of oral liquid facies were investigated .
interpretation of crystaloscopic components was achieved by applying special tables with notification of characteristics of the studied structures . to quantify microcrystals ,
an algorithm was developed for the analysis of gcm , according to which the micropreparate is examined to highlight the facies layers and determine the base . for a description of the crystal
the following parameters are estimated : length , width and degree of curvature of the main branch , main branch ratio of the width at the base and tip microcrystal report microcrystal surface perimeter and the frequency and angle of deviation degree dendrites , symmetrical ramifications of the dendrites degree from the mainline ( fig .
2 ) . further on , the integrity mainline trunk and connection area with the first degree dendrites , dendritic tip shape ( conical , oval or divided ) was investigated .
the organic inclusions were also assessed : the proportion of surface organic inclusions and field of view ; the organic inclusions location ( on the periphery in the central area or the entire area of the field of view ) ; crystal report ( membership or isolation ) .
the evaluation of mcg was performed after dried droplets examination by oral liquid , the results being expressed as the mean points depending on the types identified by the formation of crystals : 0.01.0 - at a very low extent , 1.12.0 - low , from 2.1 to 3.0 - satisfactory 3.14.0 - high , 4.1 to 5.0 - very high degree of microcrystallization . the risk of deviations of microcrystallization ( rdm )
was calculated according to the formula rdm = ( rr1)/rr 100 , rr relative risk .
the study was approved by the local ethics committee and was conducted in accordance with ethical requirements , and with the written consent of the children s parents or their legal representatives .
data analysis was performed using microsoft excel 2013 i ibm spss statistics 22.0 software using the functions and modules of these programs .
the study was approved by the local ethics committee and was conducted in accordance with ethical requirements , and with the written consent of the children s parents or their legal representatives .
data analysis was performed using microsoft excel 2013 i ibm spss statistics 22.0 software using the functions and modules of these programs .
at the initial clinical examination , performed in 27 children with gerd , dental decay was detected in 77.78% of them , the incidence of the dmft index being 2.740.33 .
dental erosion was detected in 59.26% of the total number of children , and the incidence of erosive wear was 3.960.7 .
the average risk of erosive wear was detected in 6 ( 22.22% ) children , and the reduced risk , respectively - at 7 ( 25.93% ) children , depending on the duration of gerd .
affection by dental decay and the presence of dental erosion were found in 37.04% of the children suffering from gerd .
the frequency of the dental decay in healthy children represented 55.56% , the incidence of the dmft index is 1.260.14 .
further on , in the study , we examined the central and peripheral areas of the facies obtained by dehydration of the of droplets .
the outcome of the investigation specified the main types of oral liquid microcrystallization ( mc ) .
mc type i was assessed by 5 points . fused random fractal structures are characteristic of type ii mc , gaining 4 points ( fig .
in the central part star - shaped separated crystals were present , and remained at the periphery of larger fractal crystals ( 3 points ) ( fig . 5 ) .
mc type iv was characterized by the presence of the separated crystals in the form of a branch or stem , placed relatively evenly over the whole surface of the dried droplet ( 2 points ) ( fig .
a large amount of separated stellate crystals of an oval and irregular shape located isometrically was characteristic of type v mc ( 1 point ) ( fig .
we found mc type i and ii in children with high resistance to caries , and in those with increased intensity of dental caries - types iv vi mc prevailed . for children with gerd and dental erosions , the types iv v mc were specific , while for children without any erosions and low risk of erosive wear we found types ii
, we examined not only the fractal structures , separate crystals , but also the amorphous substance .
the analysis of mcg established that in the peripheral area of the oral liquid droplet pyramidal cruciform structures predominated , in the central part linear structures were present , with a dendritic image in the form of fern , amorphous bodies were of a reduced size and crystals of large size accumulation on the surface . in the peripheral area of the oral liquid in healthy children crusade and prismatic structure prevailed . in patients with gerd affected by dental caries and those with low risk of erosive
wear the crystals structure was disturbed considerably over the entire surface of the facia where crusader crystals of different sizes were present . in children suffering from gerd and carious lesions and those with low risk of erosive wear ,
the structure of the crystals was considerably disturbed , with different sizes of crusade crystals present on the entire surface of the facia .
the peripheral area of the oral liquid facies was expanded and prominent , evidencing an abundance of elements that deteriorated the integrity of the structure ( fig .
8) , which might have been caused by the high concentration of mucin in the saliva .
oral liquid mcg in children with complicated caries , as well as in children with dental erosions , are marked by the highlighted , expanded and cracked character of the peripheral zone ( fig .
9 ) as well as the presence of crystalline structures of fern located both in the peripheral and central zones . highlighted , expanded and cracked character of the peripheral area reflects increased protein contents and conduct oral fluid pathological processes caused by free radicals .
it was found that in 96.29% of children from the control group and 7.41% of children with gerd the central area of the oral liquid mcg consisted mainly of dendritic crystals , but in the peripheral area additional inclusions were not found . in 3.7% of children in the control group and 92.59% of children in the study group
a number of morphological features in the peripheral facies of oral fluid were established :
pathological mineral compounds crystallization in the protein surroundings , manifested by the presence of crystalline inclusions , which were detected in the peripheral zone of the oral fluid facia;presence of the radial cracks network , which in clinical crystallography is considered a marker of tissue destruction processes ( fig .
10 ) , detected in children with untreated dental caries or tooth decay complications;presence of pigmentation portions ( marker of intoxication ) , which may be associated with the phenomenon of pathological crystallization of salts in the protein surroundings , were detected in children with carious activity , intensely untreated caries or tooth decay complications .
pathological mineral compounds crystallization in the protein surroundings , manifested by the presence of crystalline inclusions , which were detected in the peripheral zone of the oral fluid facia ; presence of the radial cracks network , which in clinical crystallography is considered a marker of tissue destruction processes ( fig .
10 ) , detected in children with untreated dental caries or tooth decay complications ; presence of pigmentation portions ( marker of intoxication ) , which may be associated with the phenomenon of pathological crystallization of salts in the protein surroundings , were detected in children with carious activity , intensely untreated caries or tooth decay complications .
next , we compared the specificities of mcg oral fluid in healthy children and those with gerd .
thus , in the majority of children with gerd a pathological crystallization of mineral compounds in the protein surroundings was found .
it was assumed that this marker characterizes the crystals ability to connect microorganisms and products of their activity in crystalline aggregates with organic inclusions . in children with carious intense activity , untreated caries lesions and / or dental caries complications , and in chronic persistent infection odontogenic outbreaks , the marker intoxication and / or tissue damage was found .
it was found that the degree of mc of the oral liquid in children with gerd was considerably reduced , constituting 1.730.11 points , and was 1.86 times lower compared to the indicator considered in control children ( 3.220.16 points ) ( p<0.01 , rr=2 ) . among children in the study group
there was a tendency to reduce the degree of mc damage correlated to the duration of gerd .
thus , in children with gerd duration up to 1 year , the level of the mc of oral liquid was 0.9 times lower ( p<0.05 , rr = 1.9 ) , duration of illness in children between 1 to 2 years - 1.36 times ( p<0.01 , rr = 2.4 ) , and duration of illness in children between 23 years - 2.1 times lower as compared with the estimated values in children from the control group ( p<0.05 , rr = 3.8 ) .
the analysis of the picture of dehydrated oral fluid droplet elucidated the relationship between the degree of the oral liquid and work mc caries process .
children with carious activity had mc moderate degree of the oral liquid 1.9 times ( p<0.05 , rr=2.1 ) and in children with intense carious activity - 2.3 times lower compared with controls ( p<0.01 , rr=2.6 ) .
the research results allow to conclude that the degree of oral liquid microcrystallization in children is directly related to the duration of impaired dental caries ( r=0.647 ) and degree of carious activity ( r=0.248 ) .
it is well known that saliva is a supersaturated liquid with calcium and phosphate ions and possesses the ability of enamel mineralization .
the saturated liquid state is provided by its structure , its entire volume being distributed among the micelles . under physiological conditions , saliva crystals have a branched form due to the presence in the oral liquid of micelles ca3(po4)2 , protected by the aggregation of mucin , which has a branched form .
mucins are involved in the transport of transepithelial ions ( na+ , k+ , cl ) , and in the process of biocrystalization involving ions ca2 + , constituting the organic matrix which regulates the volume and configuration of the crystal structure and the formation of crystalline structures in dendritic drying oral liquid .
the optical properties of the crystals vary significantly depending on exo- and endogenous factors , this phenomenon being applied in research , for diagnostic purposes . under unfavourable changes , in the oral cavity the structure of saliva modifies ,
thereby its mineralization function is disturbed followed by changes in the shape and properties of the crystal structure [ 2628 ] .
thus , the morphological image changes of the oral liquid due to its microcrystallization properties is an index of qualitative or quantitative disorders of salivary proteins , in particular the mucins , and is one of the earliest markers of pathological processes occurring in the organism and may be used to detect diseases in the premorbid phase , to efficiently implement the preventive and minimally invasive treatment .
therefore , the oral liquid microcrystallization disorder reflects the quantitative and qualitative disorders of mucins composition , which represents an increased risk of carious lesions .
setting the hallmarks of crystallographic changes in saliva which are influenced by functional and metabolic changes increases accuracy of diagnosis and efficiency of caries risk prediction .
dehydration method ( crystallization of bioliquids on the glass slide ) can provide an overview of the health of the entire body .
changing the shape of the crystals is a consequence of changes of the physicochemical properties of saliva .
the demineralization of dental enamel in carious process reflects the properties of the saliva , and is manifested by changing crystal structures of the oral liquid mcg .
the microcrystallization degree of the oral liquid in children is directly correlated with the gerd duration and activity of carious process .
thus , the study of morphological features of the oral liquid may serve as a predictive test that identifies impaired oral cavity protection mechanisms .
the knowledge of the mechanisms of these changes is required for the cariopreventive measures targeted on individual risk factors , while the availability of the oral liquid research , the research methodology simplicity , and the minimum costs allow its application in the dental practice .
the research method of oral liquid crystalogenesis may be applied not only in the diagnosis and prediction of diseases of the oral cavity , but it can also be used as a sensitive indicator of the operational status of the entire body .
the development of a highly informative and noninvasive methodology of premorbid conditions diagnosis and the pre - research of methods for the appropriate diagnosis of the changes occurred in the health of the population represent the most important fields of research in medicine .
the research of the oral liquid microcrystallization is a simple , non - invasive and informative method of investigation that can be applied to assess the functioning not only of the dental apparatus , but also as an indicator of the functioning of the whole organism .
the degree of the oral liquid microcrystallization in children with gerd is 1.86 times lower than this indicator assessed in healthy children .
a low level of oral liquid microcrystallization involvement correlates with the duration of gerd and carious activity process .
the study of structural features of oral liquid dehydrated droplet in children with dental caries has elucidated a number of markers of the changes produced in the oral cavity , which can be later applied in screening studies in dental practice .
the applied method of oral liquid microcrystallization offers the opportunity to study the most important pathogenic mechanisms involved in the initiation and development of dental caries and their complications , to perform dental caries prediction in order to elaborate cariopreventive measures and evaluation of their effectiveness . | ### Summary:
: background and aim.patients with disabilities have a higher prevalence of caries and dental erosions than general population .
this particularity may be assessed by the study of microcrystallization of saliva .
we investigated the oral liquid microcrystallization in children with gastroesophageal reflux disease ( gerd ) , a condition associated with dental erosions.material and methods.54 children have been clinically examined : 27 children suffering from gerd with ages between 13 and 15 , were included in the study group , and 27 healthy children - the control group .
the study of crystallographic changes of the oral liquid was performed using the method developed by shatohina , razumov sn , shabalin vn ( 2006 ) with the scanning electron microscope vega tescan ts 5130 mm.resultsthe degree of microcrystalization of the oral liquid in children with gerd was considerably reduced , ( 1.730.11 points ) and was lower than in children in the control group ( 3.220.16 points ) ( p<0.01 , rr=2 ) .
the degree of microcrystallization of oral liquid in children with gerd was 1.86 times lower than in healthy children .
this was correlated with the duration of gastroesophageal reflux.conclusionthe study of structural particularities of dehydrated droplet of oral liquid in children with gerd has elucidated a number of markers of the changes produced in the oral cavity .
these can be used in the screening research in prevention of caries and dental erosions . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: klebsiella pneumoniae ( k. pneumoniae ) is an opportunistic pathogen causing several nosocomial infections such as urinary tract infections , pneumonia , septicemia , and soft tissue infections .
health care associated infection caused by this organism has been linked to high mortality and morbidity especially among the patients admitted to intensive care units [ 3 , 4 ] .
quinolones are a group of synthetic antibacterial agents that are widely used in routine clinical practice .
the new quinolones compounds ( 6-fluoroquinolones ) exhibit broad spectrum of antibacterial activity against gram - negative , mycobacterial pathogens , and anaerobes .
moreover , these agents show a good - to - moderate oral absorption and tissue penetration with favorable pharmacokinetics in humans , creating desirable clinical efficacy in treating many kinds of infections [ 6 , 7 ] .
while the first and second generation fluoroquinolones selectively inhibit the topoisomerase ii ligase domain or dna gyrase activity , the quinolones of third and fourth generations are with more tendency for topoisomerase iv ligase .
excessive and inappropriate administration of antimicrobial agents such as quinolones has increased the emergence of multidrug resistant k. pneumoniae isolates which makes the process of antimicrobial therapy to become marginal and problematic [ 10 , 11 ] . in recent years
, several studies have demonstrated that the appearance of quinoloneresistant k. pneumoniae is rising at a faster rate , worldwide [ 12 - 15 ] . infections caused by resistant organisms are often due to extensive cross - resistance with other antimicrobials , including beta - lactams and aminoglycosides .
quinolone resistance in enterobacteriaceae mainly occurs through chromosomal mutations in the genes coding for dna gyrase and topoisomerase iv , changes in outer membrane and efflux proteins or in their regulatory mechanisms .
findings from recent studies show that plasmid - mediated resistance , associated with the pentapeptide proteins of the qnr family , might play a crucial role in quinolone compound resistance .
three major groups of qnr determinants , qnra , qnrb , and qnrs , are increasingly being identified in the clinical isolates of various enterobacterial species , worldwide .
it was in 1998 that the first plasmidmediated quinolone resistance determinant , qnra , was reported in a klebsiella pneumoniae strain from the united states . since then two qnr determinants , qnrb and qnrs have been discovered in other enterobacteriaceae species such as citrobacter koseri , escherichia coli , enterobacter cloacae , and klebsiella pneumoniae from asia and europe [ 21 - 24 ] .
to date , there has been no report for the frequency of qnr genes among k. pneumoniae isolates in iran . in the current study ,
for the first time , we described the frequency of qnr determinants ( qnra , qnrb , and qnrs ) among the isolates of quinolone non - susceptible k. pneumoniae collected from hospitals of qazvin and tehran provinces .
in this descriptive study , a total of 200 clinical isolates of k. pneumoniae were collected from hospitalized patients in several teaching hospitals in tehran and qazvin during 2012 - 2013 .
the isolates were obtained from different clinical specimens including urine , wound , trachea , secretions , blood , and ascites .
all isolates were identified by standard laboratory methods and confirmed with the api 20 e ( biomrieux , france ) strips .
all isolates were kept at -70c in trypticase soy broth containing 20% glycerol and subcultured twice before testing .
the mean age of patients ( 77 ( 38.5% ) male and 123 ( 61.5% ) female ) was 51.717.4 ( range17 - 83 ) years .
kirby - bauer disk diffusion technique was performed according to the clsi guideline to identify quinolone resistance using nalidixic acid ( 30g ) , ciprofloxacin ( 5 g ) , gatifloxacin ( 5 g ) , norfloxacin ( 10 g ) , and levofloxacin ( 5 g ) disks . in this study
the isolates were classified either as high - level quinolone resistant if the resistance to both nalidixic acid and ciprofloxacin disks was observed or low - level quinolone resistant in the cases of resistance to nalidixic acid , presence of intermediate isolates or ciprofloxacin - susceptible organisms .
antibiotic disks were purchased from the mast ( mast diagnostics group ltd , merseyside , uk ) .
e. coli atcc 25922 and pseudomonas aeruginosa atcc 27853 were used as quality control strains in antimicrobial susceptibility testing .
detection of qnra , qnrb , and qnrs plasmid - mediated quinolone resistance genes was performed using pcr and specific primers ( tab .
plasmid dna was extracted by plasmid mini extraction kit ( bioneer company , south korea ) .
pcr amplifications were applied in a thermocycler ( applied biosystems , usa ) as follows : 95c for 5min and 35 cycles of 1min at 95c , 1min at specific annealing temperature for each primer and 1min at 72c . a final extension step of 10 min at 72c was performed .
amplification reactions were prepared in a total volume of 25l ( 24l of pcr master mix plus 1l of template dna ) including 5ng of genomic dna , 2.0u of taq dna polymerase , 10 mm dntp mix at a final concentration of 0.2 mm , 50 mm mgcl2 at a final concentration of 1.5 mm , 1m of each primer , and 1x pcr buffer ( final concentration ) .
pcr products were electrophoresed on 1% agarose gel at 100 volts and later stained with ethidium bromide solution and finally visualized in a gel documentation system ( uvtec , uk ) .
the purified pcr products were sequenced by the macrogen company ( seoul , south korea ) and the sequence alignment and analysis were performed online using the blast program of the national center for biotechnology information ( http://blast.ncbi.nlm.nih.gov/blast.cgi ) .
the primers used for detection of qnr genes in k. pneumoniae isolated from qazvin and tehran hospitals .
data were summarized using mean sd ( standard deviation ) , proportional frequency and confidence interval for microbiological , clinical , and demographic characteristics .
all analyses were carried out using a statistical software package , spss for windows version 16.0 ( chicago , il , usa ) .
in this descriptive study , a total of 200 clinical isolates of k. pneumoniae were collected from hospitalized patients in several teaching hospitals in tehran and qazvin during 2012 - 2013 .
the isolates were obtained from different clinical specimens including urine , wound , trachea , secretions , blood , and ascites .
all isolates were identified by standard laboratory methods and confirmed with the api 20 e ( biomrieux , france ) strips .
all isolates were kept at -70c in trypticase soy broth containing 20% glycerol and subcultured twice before testing .
the mean age of patients ( 77 ( 38.5% ) male and 123 ( 61.5% ) female ) was 51.717.4 ( range17 - 83 ) years .
kirby - bauer disk diffusion technique was performed according to the clsi guideline to identify quinolone resistance using nalidixic acid ( 30g ) , ciprofloxacin ( 5 g ) , gatifloxacin ( 5 g ) , norfloxacin ( 10 g ) , and levofloxacin ( 5 g ) disks . in this study
the isolates were classified either as high - level quinolone resistant if the resistance to both nalidixic acid and ciprofloxacin disks was observed or low - level quinolone resistant in the cases of resistance to nalidixic acid , presence of intermediate isolates or ciprofloxacin - susceptible organisms .
antibiotic disks were purchased from the mast ( mast diagnostics group ltd , merseyside , uk ) .
e. coli atcc 25922 and pseudomonas aeruginosa atcc 27853 were used as quality control strains in antimicrobial susceptibility testing .
detection of qnra , qnrb , and qnrs plasmid - mediated quinolone resistance genes was performed using pcr and specific primers ( tab .
plasmid dna was extracted by plasmid mini extraction kit ( bioneer company , south korea ) .
pcr amplifications were applied in a thermocycler ( applied biosystems , usa ) as follows : 95c for 5min and 35 cycles of 1min at 95c , 1min at specific annealing temperature for each primer and 1min at 72c . a final extension step of 10 min at 72c was performed .
amplification reactions were prepared in a total volume of 25l ( 24l of pcr master mix plus 1l of template dna ) including 5ng of genomic dna , 2.0u of taq dna polymerase , 10 mm dntp mix at a final concentration of 0.2 mm , 50 mm mgcl2 at a final concentration of 1.5 mm , 1m of each primer , and 1x pcr buffer ( final concentration ) .
pcr products were electrophoresed on 1% agarose gel at 100 volts and later stained with ethidium bromide solution and finally visualized in a gel documentation system ( uvtec , uk ) .
the purified pcr products were sequenced by the macrogen company ( seoul , south korea ) and the sequence alignment and analysis were performed online using the blast program of the national center for biotechnology information ( http://blast.ncbi.nlm.nih.gov/blast.cgi ) .
the primers used for detection of qnr genes in k. pneumoniae isolated from qazvin and tehran hospitals .
data were summarized using mean sd ( standard deviation ) , proportional frequency and confidence interval for microbiological , clinical , and demographic characteristics .
all analyses were carried out using a statistical software package , spss for windows version 16.0 ( chicago , il , usa ) .
in this study , the bacterial isolates were recovered from different clinical specimens including urine ( 110- 55.0% ) , trachea ( 59 - 29.5% ) , wound ( 18 - 9.0% ) , blood ( 8 - 4% ) , and ascites ( 5 - 2.5% ) .
these isolates were obtained from the patients admitted to intensive care units ( 96 - 48.0% ) , internal medicine ( 54 - 27.0% ) , infectious diseases ( 35 - 17.5% ) , surgery ( 13 - 6.5% ) , and orthopaedic ( 2 - 1.0% ) wards .
the results of antimicrobial susceptibility testing showed the resistance rates against the antimicrobial agents used in our study varied between 20% and 58% .
overall , nalidixic acid ( 58% ) and ciprofloxacin ( 34.5% ) revealed the highest rates of resistance among the antimicrobials tested whereas levofloxacin and norfloxacin also demonstrated high susceptibility rates of 80% and 77% , respectively ( tab .
ii ) . in total , 66 ( 53.2% ) and 58 ( 46.8% ) of isolates showed high and low - level quinolone resistance , respectively .
ci = 95% confidence interval pcr and sequencing showed the presence of qnr - encoding genes in 49 ( 39.5% ) of quinolone non - susceptible k. pneumoniae isolates among those qnrb1 ( 38- 30.6% ) was the most common gene followed by qnrb4 ( 12 - 9.7% ) and qnrs1 ( 2 - 1.6% ) genes either alone or in combination .
as shown in table iii , qnrb1 was found to coexist with qnrb4 in 3 ( 2.4% ) isolates .
overall , 25 ( 37.9% ) high level quinolone resistant isolates carried qnr genes in which 19 ( 28.8% ) , 4 ( 6.1% ) , and 2 ( 3% ) isolates carried qnrb1 , qnrb4 , and qnrs1 genes , respectively .
in addition , 24 ( 41.4% ) low level quinolone resistant isolates were positive for qnr genes among those 19 ( 32.8% ) isolates carried qnrb1 gene followed by qnrb4 in 8 ( 13.8% ) isolates . among the high and low - level quinolone resistance isolates , qnrb1 was the most frequent gene compared to other genes .
table iv shows that qnr - positive isolates were mostly recovered from urine ( 42.9% ) followed by trachea secretion ( 36.7% ) samples .
the patients affected by these organisms were mostly admitted to icu ( 59.2% ) and internal medicine ( 20.4% ) wards .
ci : 95% confidence interval frequency of qnr - positive k. pneumoniae isolates based on hospital wards and source of specimens ( n = 49 ) .
quinolones are among the most commonly administered antimicrobials routinely used for the treatment of serious infections caused by k. pneumoniae and other members of the genus enterobacteriaceae .
however , the development of resistance to these antibiotics makes the treatment decision difficult , leading to treatment failures . in recent years ,
plasmid mediated quinolone resistance among enterobacterial isolates has been reported in several studies , worldwide . however , the number of reports on prevalence of qnr genes among iranian enterobacteria isolates is only limited to few studies [ 28 , 29 ] . in the present study , 58% and 34.5% of isolates
raei et al demonstrated that 36.2% and 34.1% of urinary k. pneumoniae isolates were resistant to ciprofloxacin and nalidixic acid , respectively .
in another study from iran , zamani et al found that 28.57% and 23.8% of klebsiella spp .
hence , the emergence of resistant isolates against broad spectrum antibacterial agents in our hospital settings seems to be linked with improper and widespread administration of these antibiotics .
the present study demonstrates a high prevalence ( 39.5% ) for plasmid - mediated quinolone resistance determinants among quinolone non - susceptible k. pneumoniae isolates in iran .
the prevalence rate found in our study is higher than those reported by kim et al from korea ( 10% ) , wang et al from china ( 11.9% ) , dahmen et al from tunisia ( 16% ) , yan et al from china ( 16.2% ) , and wang et al from the united states ( 11.1% ) but still lower than that found by bouchakour et al in morocco in which 50% of esbl - producing k. pneumoniae isolates were shown to carry qnr determinants .
this might be indicative of a rising trend in the rate of plasmid mediated quinolone resistance among the genus of enterobacteriaceae . in the current study , 25% of qnr - positive isolates
as plasmid mediated quinolone resistance determinants produce only low - level resistance to quinolones , it can be hypothesized that high level resistant pattern is possibly caused by another mechanisms such as chromosomal mutation which was not evaluated in the present study .
considering the findings of the present study , it is obvious that most qnr - positive k. pneumoniae isolates were mostly obtained from the patients admitted to icus .
long term icu stay , broad spectrum antibiotics intake , chronic underlying conditions , and the application of invasive techniques and devices probably make the patients more susceptible to infections caused by these resistant organisms . in the present study , 30.6% , 9.7% , and 1.6% of quinolone non - susceptible k. pneumoniae isolates carried qnrb1 , qnrb4 , and qnrs1 genes alone or in combination , respectively .
we believe that this is the first report of qnrs1 , qnrb4 , and qnrb1 genes among the clinical isolates of k. pneumoniae collected from two distinct provinces of iran . in a study by pakzad
et al reported from iran , 9 ( 37.5% ) and 4 ( 20.8% ) of esbl - producing e. coli isolates were positive for qnra and qnrb genes , respectively .
the presence of qnra ( 25.8% ) , qnrb1 ( 1.17% ) , and qnrs ( 1.17% ) genes among esblproducing salmonella spp . was also reported in a study by saboohi et al from iran . in another study from iran ,
seyedpour et al showed that 30.4% of community isolates of k. pneumoniae harbored qnr and/or aac ( 6')-ib - cr genes . in taiwan ,
wu et al described the presence of qnrb4 ( 3.6% ) , qnrs1 ( 2.8 , and qnrb2 ( 2.3% ) genes in the clinical isolates of k. pneumoniae .
robicsek et al in the united states reported that 14% and 6% of ceftazidime - resistant k. pneumoniae isolates harbored qnra and qnrb genes , respectively .
dahmen et al from tunisia showed qnra was more prevalent among k. pneumoniae isolates whereas qnrb1 was the most prevalent genes among e. cloacae isolates followed by qnrb2 and qnrs1 .
similarly , yan et al in their report from china demonstrated that 8.1% , 4.1% , and 4.1% of esbl - producing k. pneumoniae isolates were positive for qnra , qnrb , and qnrs genes , respectively .
finally , wang et al in a study carried out in china reported that 62 ( 15.1% ) , 25 ( 6.1% ) , and 10 ( 2.4% ) of esbl - producing k. pneumoniae isolates were positive for qnrs , qnrb , and qnra genes , respectively .
findings of the present study reveal a high prevalence for plasmid - mediated quinolones resistance due to qnr genes among the clinical isolates of k. pneumoniae in iran .
the appearance and spread of such resilient organisms within the medical centers around the country not only brings about issues of great concern for human health but also raises questions on how to achieve a successful antibiotic therapy through planning a comprehensive infection control guideline to avoid further spread of these resistant organisms within our medical settings .
our data also highlights the necessity for establishing an appropriate infection control strategy and sensible antibiotic therapy . | ### Summary:
: summarybackground.plasmid-mediated quinolone resistance is an increasing clinical concern , globally .
the major objective of the present study was to identify the qnr - encoding genes among the quinolone non - susceptible k. pneumoniae isolates obtained from two provinces in iran.methods.a total of 200 k. pneumoniae isolates were obtained from hospitals of qazvin and tehran , iran .
the identification of bacterial isolates was carried out by standard laboratory methods and api 20e strips .
susceptibility to quinolone compounds were examined by standard kirby - bauer disk diffusion method according to the clsi guideline .
pcr and sequencing were employed to detect qnra , qnrb and qnrs - encoding genes.results.of 200 k. pneumoniae isolates , 124 ( 62% ) were nonsusceptible to quinolone compounds among those 66 ( 53.2% ) and 58 ( 46.8% ) isolates showed high and low - level quinolone resistance rates , respectively . out of 124 quinolone
non - susceptible isolates , qnr - encoding genes were present in 49 ( 39.5% ) isolates with qnrb1 ( 30.6% ) as the most dominant gene followed by qnrb4 ( 9.7% ) , and qnrs1 ( 1.6% ) either alone or in combination.conclusions.this study , for the first time , revealed the high appearance of qnrb1 , qnrs1 and qnrb4 genes among the clinical isolates of k. pneumoniae in iran .
therefore , the application of proper infection control measures and well - established antibiotic administration guideline should be strictly considered within our medical centers . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: to have white healthy teeth has been a wish often quite hard to accomplish , although represents a human concern since antiquity .
modern society has increased the importance of individual aspect , as shown by fashion , cosmetics , body esthetics and dental esthetics in particular .
dental cosmetics is addressed to all patients that are preoccupied by their smile , being most frequently an option for the the young patients that suffered various accidents or those who , for different reasons ( malnutrition , various illnesses , poor hygiene during childhood and adolescence ) have their teeth very much affected by the dental caries , and mostly by its complications considering pulpectomy and even teeth extraction . , an increased intake of coffee , cigarettes , soft drinks with artificial colorants associated to all the problems listed above have a disastrous esthetic result , the teeth getting a darker color and the smile and the general aspect of the patient gets very bad .
treating these colored teeth requires a bleaching process on the teeth and eventually a partial or total cover of the dental crowns .
the bleaching process improves the dental aspect and the crowns would improve the esthetics of the overall mouth aspect .
frequently used for the dental bleaching process are the following substances : hydrogen peroxide , carbamide peroxide , sodium perborate , no matter which whitening technique we use or the bleaching substance that is being used , the way of action is the same , as an oxidation reaction , having as result the release of oxygen molecules .
for whitening non vital teeth the bleaching agent is applied on the enamel surface ( external whitening ) as well as inside the pulp chamber ( internal bleaching ) . the external whitening technique for the non vital teeth
is based on the fact that the bleaching agent is penetrating the enamel cells , reaching the dentine where is affecting the colored organic molecules .
the internal bleaching procedure of the non vital teeth is based on the fact that the bleaching agent reaches the dentine faster , directly inside the pulp chamber , and so it reaches the colored molecules faster , degrading them .
the higher the concentration of the bleaching substances is the higher is the rate of the oxygen molecules release is and the time of action is shorter .
this is the reason we choused for the presented case a product based on hydrogen peroxide 38% ( opalescence xtraboost , ultradent ) .
the whitening technique used is paint - on , which means individual applications of the whitening gel , on each tooth .
patient f.r , age 19 presented herself in the dental office , being unhappy of the aspect of her upper front teeth .
the patients was avoiding smiling , while speaking had a very small mouth opening , and was always paying very much attention on how much of her teeth was showing .
the medical interrogatory revealed the fact the patient had several interventions on her upper front teeth for treating many carious lesions occurred at this level .
the clinical exam showed the existence of several composite obturations , on the teeth 12 , 21 , 22 .
these teeth had a yellow - grey coloration , characteristic for the non vital teeth , but also a pink- yellow coloration , due to the endomethasone used for the endodontic treatment , these teeth , 12 , 21 , 22 were investigated with x - rays , noticing the extitance of correct root canal obturations .
the coronal obturations had an incorrect marginal adaptation , with a brown - grey color on the edges .
the effect was highly inestethic , considering the size of the obturation going over the vestibular side of the teeth . the working technique . during the first session we cleaned all the teeth with ultrasonic device and professional brushing , in order to remove all stains and coloration on the dental surfaces .
( fig.1 ) the initial situation , after the cleaning procedures during the second session we made an external bleaching .
the hydrogen peroxide is very caustic for the soft tissues of the oral cavity , needing a very well done isolation of the teeth when we apply the gel .
the opalescence xtraboost kit contains a syringe with a special resin which we applied over the soft tissues around the cervical areas of the teeth , and we cured it with the curing lamp .
additionally , cotton rolls have been used and plastic retractors in order to protect the cheeks and the lips of the patient.(fig.2 ) .
the action time necessary for the gel is , according to the producer indications , 1 - 15 minutes , and after this time the excess was removed with cotton pellets and washed thoroughly .
applying the whitening gel after we isolated the teeth again the whitening gel was applied on the external surfaces of the teeth as well as inside the pulp chamber during the third session we removed the coronal obturations ( fig.4 ) .
even if we noticed on the x - ray a nice and clean root canal filling that was previously made we had to be sure the root canal was perfectly sealed .
the lack of perfect root canal sealing there is a risque of infiltration of the whitening gel towards apical area having as consequence the occurrence of irritation and necrosis in the alveolar bone .
we removed 2 mm from the coronal section of the root canal filling and replaced it with ionomer cement .
we also made sure all the former coronal restoration has been removed ( fig.5 ) .
removal of the coronal restaurations removal of the obturation materials from the root canal , partially after the procedure the gel was completely removed and we closed the pulp chamber with a cotton pellet and provisional cement .
same steps were followed during the next sessions . to prevent external bone recession we applied inside the pulp chamber a calcium hydroxide , which has the role to penetrate the dentinal tubes all the way to the superficial layers ( fig.6 ) .
a total of 5 sessions were needed to obtain a whitening on the 12 , 21 , 22 teeth and to obtain a similar color as the other teeth .
we used an international color key , vita , and the chosen color for this case was a2 .
as was proved during the working technique the whitening process of the teeth is not invasive .
although several sessions are required the results are very impressive most of the time .
teeth bleaching is harmless process but there are some conditions that have to be respected : correct and complete soft tissue isolation ( gums , lips , cheeks ) , in order to protect them of eventual burns caused by the peroxide , and , for the non vital teeth , to apply at the end of the whitening process calcium hydroxide inside the pulp chamber to prevent external resorbation .
, , this clinical case could have been solved as well by using veneers or porcelain crown .
but we considered the young age of the patient and the conservation of the hard dental tissues as much as possible , and so bleaching and composite restorations were the best option .
the oxygen affects the adhesion power of the bonding and composite , which why we waited 2 weeks until the final restorations were made .
using the teeth whitening technique together with the coronal esthetic restorations we avoided a great disruption of hard dental tissues , which would have been made during a prosthetic treatment .
because we treated non vital teeth we have been able to use a bleaching agent with a high concentration , 38% , therefore a positive result was obtained in a shorter time .
respecting the producer indications and the working technique for the on vital teeth we consider that we avoided the apparition of immediate complications as well as long term complications , with an esthetic great result . | ### Summary:
: commonly used in cosmetic dentistry teeth whitening can be used combined with other restorative techniques during dental treatment .
non - vital teeth whitening is necessary whenever we need an improvement of their aspect , as it s a known fact that these teeth can have a grey or pink - grey coloration when they are not correctly endodontical treated . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: familial hypercholesterolemia ( fh ) is a genetic disease resulting in elevated low - density lipoprotein cholesterol ( ldl - c ) levels .
most individuals inherit a mutation from one parent , resulting in the heterozygous form heterozygous familial hypercholesterolemia ( hefh ) .
hefh affects 1 in 500 people , making it one of the most common genetic diseases , yet continues to be underrecognized with < 1% of cases diagnosed in many countries , including both developed and developing nations 13 . without treatment , individuals with fh are about 20 times more likely to develop premature coronary heart disease 4 . to the best of our knowledge ,
a 41-year - old man of portuguese ancestry presented with a chief complaint of cosmetically distressing nodules affecting both hands and the right elbow .
these were slowly increasing in size for several years with no history of tenderness , joint stiffness , or trauma and reminded him of nodules on the hands of his maternal uncle .
he was in good general health with no comorbidities , smoking , or drug use .
family history revealed a sister who had a myocardial infarction at 45 years of age and was on treatment with several lipid - lowering medications .
examination showed a normotensive male with a body mass index of 32 kg / m .
inspection and palpation of the hands and elbow demonstrated multiple tendon xanthomas ( figs.1 and 2 ) .
. thickened , xanthomatous achilles tendons are subtle findings that can be better detected by careful palpation in addition to visual inspection .
laboratory testing was significant for fasting total cholesterol of 403 mg / dl , ldl - c of 347 mg / dl , high - density lipoprotein cholesterol ( hdl - c ) of 35 mg / dl and normal triglyceride level .
other investigations including electrocardiogram , chest radiograph , and echocardiography were unremarkable . given these findings , the dutch lipid clinic network criteria ( table1 ) were applied .
this diagnostic scoring of our patient was positive for family history , tendon xanthomas , arcus cornealis in a patient < 45 years and ldl - c levels > 330 mg / dl . with a total score of 19 points the diagnosis of definite hefh
diagnosis could also have been made using similar validated clinical criteria developed by the simon broome register group 5 . as noted by the national lipid association expert panel on fh ,
genetic screening is generally not needed and up to 20% of clinically definite fh patients have no identifiable mutation , so a negative genetic test does not exclude fh 4 . the dutch lipid clinic network criteria for diagnosis of heterozygous familial hypercholesterolemia source : world health organization 1 .
xanthomas are not seen in polygenic hypercholesterolemia , while in familial combined hyperlipidemia triglyceride levels are generally elevated .
xanthomas can occur in sitosterolemia and cerebrotendinous xanthomatosis , but these have other manifestations and do not involve ldl metabolism 2 .
lipid - lowering therapy was initiated with dietary and lifestyle modifications and a statin . on follow - up visits ,
statin therapy was increased to maximum dose with biochemical monitoring of liver function , but ldl - c concentration remained greater than 50% from baseline .
ezetimibe coadministration was commenced , which resulted in a favorable ldl - c reduction . in keeping with guidelines ,
cascade screening was offered to the family and the patient 's sister was diagnosed with hefh .
the medped ( make early diagnosis - prevent early death ) study criteria , which define cut - off ldl - c values based on age and degree of relation , were used for this purpose 4 . at 1-year postdiagnosis
the patient continued to do well with no evidence of premature cardiovascular disease or progression of the tendon xanthomas .
xanthomas are not seen in polygenic hypercholesterolemia , while in familial combined hyperlipidemia triglyceride levels are generally elevated .
xanthomas can occur in sitosterolemia and cerebrotendinous xanthomatosis , but these have other manifestations and do not involve ldl metabolism 2 .
lipid - lowering therapy was initiated with dietary and lifestyle modifications and a statin . on follow - up visits ,
statin therapy was increased to maximum dose with biochemical monitoring of liver function , but ldl - c concentration remained greater than 50% from baseline .
ezetimibe coadministration was commenced , which resulted in a favorable ldl - c reduction . in keeping with guidelines ,
cascade screening was offered to the family and the patient 's sister was diagnosed with hefh .
the medped ( make early diagnosis - prevent early death ) study criteria , which define cut - off ldl - c values based on age and degree of relation , were used for this purpose 4 . at 1-year postdiagnosis
the patient continued to do well with no evidence of premature cardiovascular disease or progression of the tendon xanthomas .
heterozygous familial hypercholesterolemia occurs most commonly due to a mutation of the ldl receptor gene , the discovery for which goldstein and brown received the nobel prize in medicine .
fh is one of the few genetic disorders which meet all of the world health organization criteria for large - scale screening 1 . despite this
, fh is underdiagnosed by cardiologists and general practitioners 6 and as in the case of this patient 's sister , sometimes remains undetected even after myocardial infarction 7 .
this case report highlights fh in the caribbean region , where at present no systematic approaches to identify patients with fh and offer cascade screening to their relatives exist .
premature cardiovascular disease exerts a heavy burden on the region and it is likely that fh represents a significant cause of preventable disease . it has been shown that patients with fh have abnormal arterial structure and function but this can be improved with intensive statin therapy 8 .
therefore , this life - threatening disease is treatable once identified . among fh patients , xanthomas
physicians , including general practitioners , cardiologists , and pediatricians , must identify xanthomas during physical examination and utilize validated clinical scoring such as the dutch lipid clinic network criteria ( table1 ) .
fh is autosomal codominant so it is essential to offer cascade screening to first - degree relatives of diagnosed hefh patients who are at high risk as demonstrated in the case presented .
implementation of cascade screening will identify many currently unknown cases , including young patients who would otherwise remain undetected .
finally , establishment of a national or regional patient registry is recommended to address the regional void in research and track outcomes over time .
adopting these strategies has great potential to improve detection of fh allowing aggressive treatment and reducing adverse cardiovascular outcomes , in both developed and developing countries .
| ### Summary:
: key clinical messagefamilial hypercholesterolemia ( fh ) is a common but commonly missed diagnosis .
tendon xanthomas are a physical sign strongly suggestive of fh .
physicians must identify tendon xanthomas , apply validated clinical scoring such as the dutch lipid clinic network criteria and offer cascade screening .
this approach will increase recognition of fh . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: diabetes
mellitus ( dm ) was the 4th leading cause of death in taiwan in 2007 .
many diabetic patients have an increased risk of atherosclerosis ,
cerebrovascular disease , and peripheral vascular diseases .
the abnormalities in nutrient metabolism and elevated inflammatory
mediators resulting from dm lead to impairment of wound healing and vulnerability
to infection and foot ulcers .
diabetic
lower limb ischemia caused by arterial occlusion is the most common foot injury
leads to lower extremity amputation in dm patients .
lower extremity bypass surgery ( lebs ) is indicated to prevent limb loss in patients
with critical leg ischemia .
previous studies
revealed that a large reduction in major amputation rates is associated with
the increase of lebs [ 3 , 4 ] .
however , the efficacy of lebs on inflammatory
reaction in dm patients has not been evaluated and
the changes in inflammatory mediators before and after the lebs remain unknown .
endothelial
dysfunction accompanied by upregulated inflammatory mediators is a major
contributing factor to the pathogenesis of diabetic vascular complications .
overexpressions of cellular adhesion molecule
facilitate leukocyte - endothelial interactions which may aggravate inflammatory
reaction and tissue damage .
previous
study demonstrated that increased levels of plasma soluble adhesion molecule
occur in type 2 patients .
et-1 stimulates
vascular smooth muscle cells proliferation , a major step in the development of
atherosclerosis .
other key roles of no include inhibiting platelet aggregation , smoothing
muscle cells proliferation , reducing monocyte adherence , and so forth .
previous study showed that at the onset of
diabetes , the release or response to no is reduced .
both et-1 and no are important mediators in
maintaining vascular functions . since lebs
increases blood flow to tissues that may carry
oxygen and nutrients
to the lower extremities and improve
the healing of the tissues , we hypothesized that the inflammatory process and vascular dysfunction
are attenuated in dm patients undergoing lebs .
therefore , the aim of this study was to investigate whether reperfusion
of the lower extremities may improve the inflammation and endothelial
dysfunction in dm patients .
this study was conducted from april
to december 2006 at taipei medical university - affiliated wan fang
hospital .
twenty one type 2 dm patients with
severe diabetic lower limb ischemia and underwent lebs were enrolled in the
experimental group . the diabetes
duration was 630 years , with a mean of 18.2 years .
insulin and combined therapy if necessary were used to control blood
glucose to within a range of 106259 mg / dl .
no leg infection was observed in lebs patients , possibly because the
operation was successful and the antibiotics used after the surgery .
the protocol was approved by the hospital ethics
committee , and all the patients gave their informed written consent prior to
their participation in this study .
blood
samples were taken from each patient before and at 1 day and 7 days after the lebs in
dm patients .
ten milliliters of blood
were drawn after 12 hours of fasting , placed in tubes containing ethylene
diaminetetraacetic acid .
fresh blood samples were collected for the analysis of leukocyte cd11a / cd18 and cd11b / cd18 expressions .
plasma samples obtained from whole blood
centrifugation at 3000 rpm for 10 minutes were stored at 80c until further analysis .
total
cholesterol , low - density lipoprotein cholesterol , high - density lipoprotein
cholesterol , triglyceride , and creatinine were analyzed by an autoanalyser ( hitachi 7170 , tokyo , japan ) .
blood hba1c was measured using a commercial
kit ( helena biosciences , sunderland , uk ) .
concentrations of plasma et-1 , soluble
intracellular adhesion molecule ( sicam)-1 ,
soluble vascular cell adhesion molecule ( svcam)-1 ,
and c - reactive protein ( crp ) were
measured using commercial enzyme - linked immunosorbent assay ( elisa ) kits ( r&d systems ,
minneapolis , mn , usa ) .
the minimum detectable
dose of et-1 , sicam-1 , svcam-1 , and crp were 0.064 pg / ml , 0.35 ng / ml , 0.6 ng / ml ,
1 ug / ml , respectively , for no2/no3 was
0.25 um .
one hundred microliters of fresh blood was incubated with
10 ul fluorescent isothiocynate ( fitc)-conjugated
mouse monoclonal antihuman cd11a and phycoerthrin ( pe)-conjugated mouse
monoclonal antihuman cd18 ( serotec , oxford , uk ) for 15 minutes at 4c .
the proportions of cd11a / cd18 expressed on lymphocytes were analyzed by
flow cytometry ( coulter , miami , fl ) .
the results are
presented as a percentage of cd11a - presenting
cells in 1 10 lymphocytes .
to
measure cd11b / cd18 expressions on polymorphoneuclear neutrophils ( pmns ) , fitc - conjugated
mouse monoclonal antihuman cd11b and pe - conjugated mouse monoclonal antihuman
cd18 ( serotec ) were added into 100 l of fresh
blood .
the results are
presented as a percentage of cd11b / cd18 expression in 1 10 pmns .
lymphocytes and pmns were
gated on the basis of the forward scatter and side scatter profiles and were
analyzed for the expressions of cd11a / cd18
and cd11b / cd18 , respectively .
the differences among
different time points were determined by one - way analysis of variance .
there were no significant differences in
plasma et-1 and no levels ( table 2 ) , nor
did any differences in plasma svcam , sicam , and crp levels before and after the operation
( table 3 ) . also , leukocyte cd11a / cd18 and cd11b / cd18 expressions before and after
the operation did not differ in dm patients ( table 4 )
this study
evaluated an lebs - induced change in inflammatory response and endothelial
function .
we found that compared with the
preoperative condition , the mediators related to inflammation and vascular
function did not change in type 2 dm patients at early and late stages after
lebs .
diabetic patients often have endothelial dysfunction and
releasing of endothelins is partly responsible for this .
previous report found that plasma et-1 levels
are enhanced in patients with poor glycemic control and et-1 levels were
even higher in dm patients complicated with vascular diseases . a study performed by schneider
et al
. found that diabetic patients taking angiotensin converting enzyme
inhibitors had lower plasma et-1 levels than patients without , indicating that
medical intervention did improve et-1 levels .
in addition to et-1 , no is also an important regulatory determinant of
vascular tissue homeostasis .
no plays a
protective role by suppressing abnormal proliferation of vascular smooth muscle
following various vascular interventions such as bypass grafting . in this study
, we did not observe differences
in plasma et-1 and no levels before and 1 or 7 days after surgery .
this result may indicate that lebs performed
in this study did not , at least in the short run , improve endothelial function
in dm patients .
crp levels were correlated with
peripheral artery disease severity in patients undergoing lebs . icam-1 and vcam-1 are adhesion proteins
synthesized by endothelial cells .
previous study showed that tissue icam-1
levels were positively correlated with blood glucose levels .
adhesive interactions between leukocytes and endothelial
cells are involved in inflammatory or immunologic response mechanisms .
adhesion molecules on endothelial cells are
the ligands of integrins on leukocytes . cd11a
and cd11b / cd18 are members of the leukocyte adhesion molecules 2 integrin .
cd11a / cd18 are exclusively
expressed on leukocytes and cd11b / cd18 are abundant in pmns . in this
study , we analyzed lymphocyte cd11a / cd18 because the function of t - lymphocyte
subsets is important on influencing the type of immunity and the inflammatory
response to infection .
cd11b / cd18
expressed by neutrophil is important in mediating neutrophil - endothelial cell
interactions and binding to adhesion molecule on the surface of vascular
endothelial cells [ 21 , 22 ] .
previous reports revealed that
neutrophil cd11b / cd18 increases in infected patients and is correlated with
microvascular dysfunction . in this study , we did not observe
the difference in leukocyte cd11a / cd18 and cd11b / cd18 expressions before and
after the operation .
this result was
consistent with plasma svcam-1 , sicam-1 , and crp levels that these inflammatory
proteins did not change after lebs .
these
findings indicate that compared with preoperative state , lebs did not attenuate
inflammatory reaction in dm patients .
although lebs increases blood flow to the
peripheral tissues , surgical injury stimulates the production of endogenous
inflammatory mediators . besides
,
reperfusion of the ischemic tissues may also result in exaggerated inflammatory
response [ 24 , 25 ] , this may make the alteration of inflammatory mediators not so obvious
before and after the surgery . in conclusion , this is a pilot study
to demonstrate that compared with the preoperative condition , no
differences in plasma concentrations of et-1 , no , and inflammatory mediators were
observed in dm patients after lebs .
this
result suggests that the effect of lebs on alleviating the inflammatory
reaction and improving endothelial function in dm patients was not obvious . | ### Summary:
: diabetes mellitus ( dm ) is a metabolic disorder characterized by hyperglycemia and dyslipidemia
. the abnormalities in nutrient metabolism and elevated inflammatory mediators resulting from dm lead to impairment of wound healing and vulnerability to infection and foot ulcers .
diabetic lower limb ischemia often leads to limb necrosis .
lower extremity bypass surgery ( lebs ) is indicated to prevent limb loss in patients with critical leg ischemia .
this study investigated the alteration of inflammatory and endothelium dysfunction markers before and after lebs in dm patients .
twenty one type 2 dm patients with lebs were included .
blood was drawn before and at 1 day and 7 days after surgery in the patients .
plasma soluble cellular adhesion molecule levels and blood leukocyte integrin expressions were measured .
also , plasma concentrations of endothelin-1 and nitric oxide were analyzed to evaluate the vascular endothelial function .
the results showed that there were no significant differences in plasma cellular adhesion molecules , endothelin-1 and nitric oxide levels , nor did any differences in leukocyte integrin expressions before and after the operation .
these results suggest that the efficacy of lebs on alleviating inflammatory reaction and improving endothelial function in dm patients was not obvious . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: apatinib is a novel anti - angiogenic agent targeting vascular endothelial growth factor receptor-2 , which is effective in patients with chemotherapy - refractory gastric cancer .
there are no reports of concurrent apatinib with local radiation therapy in elderly patients with advanced gastric cancer .
we present the first published report of a 70-year - old male patient with advanced gastric cancer who received concurrent apatinib and local radiation therapy after failure of oxaliplatin and s-1 chemotherapy .
the patient received concurrent apatinib and local radiation therapy and was followed up 7 months after therapy without disease progress , 14 months later indicated extensive metastasis and this patient died of pulmonary infection .
elderly patients with advanced gastric cancer may benefit from concurrent apatinib with local radiation therapy when chemotherapy is not tolerated or successful .
further studies are needed to investigate the clinical outcomes and toxicities associated with concurrent apatinib and radiation therapy in gastric cancer .
the gastric cancer is the fifth leading cause of cancer in the world and china accounts for approximately 40% of global gastric cancer incidence annually .
patients diagnosed with advanced gastric cancer usually have a poor prognosis , with a median overall survival ( os ) of 1 year when treated with chemotherapy .
gastric cancer frequently occurs in elder individuals , and conventional cancer therapies are difficult to administer due to challenges associated with age , comorbidities , and cancer - related debilitation . in order to avoid the toxicity associated with conventional therapies and
improve outcomes in this patient population , many research studies have focused on the application of novel molecular targeted agents . in the 1970s ,
angiogenesis was reported to play a key role in tumor growth . since this initial research
, multiple antiangiogenic agents have been developed and studied in clinical trials . although these agents show promising antitumor effects , their efficacy when used as monotherapy is limited .
therefore , these agents have been integrated with conventional cancer therapies , including chemotherapy and radiotherapy , in order to enhance antitumor activity .
apatinib is a novel oral antiangiogenic agent that shows efficacy in the inhibition of tumor angiogenesis .
phase ii and iii clinical trials suggest apatinib can improve os and progression - free survival ( pfs ) in advanced gastric cancer patients who have experienced treatment failure on 2 or more prior chemotherapy regimens .
apatinib was approved and launched in the people 's republic of china in 2014 as a second - line treatment for gastric cancer patients . here ,
we report the case of a 70-year - old male patient with advanced gastric cancer , who received concurrent apatinib and local radiation therapy .
on december 28 , 2014 , a 70-year - old man complaining of abdominal pain , dizziness , and nausea was referred to the hebei general hospital , hebei , china .
gastroscopy showed irregular hemorrhagic ulcerative lesions extending from the gastric body to the lesser curvature and pyloric stenosis of the stomach .
gastric biopsy revealed adenocarcinoma . on january 7 , 2015 , palliative gastrectomy plus roux - en - y near esophagojejunostomy were performed .
diffuse enlarged para - aortic and anterior superior pancreatic lymph nodes , as well as lymph nodes around the common hepatic artery , could not be resected .
immunohistochemistry showed the following : human epidermal growth factor receptor 2 ( her-2 ) ( + ) , vascular endothelial growth factor ( vegf ) ( + ) , cd31 ( + ) , cd105 ( + ) ( fig .
e ) , triple positive ( tp ) ( + ) , glutathione s - transferase ( gst- ) ( + + + ) , topoisomerase enzyme ii ( topoii ) , p53 ( ) , and ki-67 ( 70% ) .
postoperative pathology : ( a ) hematoxylin and eosin staining indicating moderately differentiated gastric adenocarcinoma ( 100 ) .
( b ) immunohistochemistry showing the expression of her2 ( + ) ( 100 ) .
( c ) immunohistochemistry showing the expression of vegf ( + ) ( 100 ) .
( d ) immunohistochemistry showing the expression of cd31 ( + ) ( 100 ) .
( e ) immunohistochemistry showing the expression of cd105 ( + ) ( 100 ) .
the patient was administered 1 cycle of chemotherapy with oxaliplatin and s-1 ; however , the treatment was terminated , as the patient could not tolerate the associated gastrointestinal disturbances . on february 2 , 2015 ,
positron - emission tomography computed tomography ( pet - ct ) showed extensive distant metastasis ( left supraclavicular and mediastinal lymph nodes , and lymph nodes throughout the abdominal cavity ) .
the patient 's eastern cooperative oncology group ( ecog ) performance status was 2 , and his body mass index ( bmi ) was 19 ; therefore , he was considered to be at risk of malnutrition .
oral apatinib 850 mg once a day combined with and following radiotherapy was prescribed .
informed consent was obtained from the patient prior to treatment . in an attempt to improve tolerance to treatment
the patient received a dose of 64 gy in 30 fractions to the mediastinum and doses of 52 gy in 26 fractions to the other abdominal metastatic lesions ( n = 5 ) .
the left supraclavicular lymph node was treated with apatinib alone ( figs . 2 and 3a c ) .
pet - ct scans : ( a ) left supraclavicular metastasis ( arrow ) before apatinib treatment ; ( b ) left supraclavicular metastasis ( arrow ) after apatinib treatment ; ( c ) mediastinum metastasis ( arrow ) before concurrent apatinib and radiotherapy ; ( d ) mediastinum metastasis ( arrow ) after concurrent apatinib and radiotherapy ; ( e ) abdominal metastasis ( arrow ) before concurrent apatinib and radiotherapy ; ( f ) abdominal metastasis ( arrow ) after concurrent apatinib and radiotherapy .
pre- and postoperative imaging : ( a ) clinical target volume ( red ) of the left supraclavicular region ; ( b ) clinical target volume ( red ) of the mediastinum ; ( c ) clinical target volume ( red ) of the abdominal cavity ( a c ) gross tumor volume and planning target volume contours omitted for clarity ) ; ( d ) gastric endoscopy showing anastomotic stenosis due to gastric cancer with intragastric hemorrhage ; ( e ) pet - ct showing extensive distant metastasis in supraclavicular lymph nodes ( arrow ) , the mediastinum ( arrow ) , and multiple parts of the abdominal cavity ( circle and arrow ) before concurrent apatinib and radiotherapy ; ( f ) pet - ct showing a partial response in the supraclavicular lymph nodes , mediastinum , and multiple parts of the abdominal cavity after concurrent apatinib and radiotherapy .
a pet - ct scan performed 2 weeks after radiotherapy showed an 80% reduction in the maximum standardized uptake value ( suvmax ) of 2-deoxy-2-[f]fluoro - d - glucose ( fdg ) .
fdg uptake was higher in the left supraclavicular lymph node compared to the metastatic regions treated with concurrent apatinib and radiation therapy . according to response evaluation criteria in solid tumors ( recist ) ,
the patient received further radiotherapy ( 66 gy in 28 fractions ) to the left supraclavicular lymph node due to residual metastasis .
two months after therapy , chest , and abdominal ct scans indicated stable disease ; anemia and gastrointestinal symptoms had improved , ecog performance status was 0 , and bmi was 22 .
hematologic toxicity , hypertension , renal dysfunction , proteinuria , and hand foot syndrome were not observed during apatinib therapy . in september 2015 ,
a follow - up examination showed increased carbohydrate antigen ( ca ) 125 and ferritin ; however , gastroscopy and abdominal ct revealed no abnormalities . in november 2015
one month later , the patient again experienced intermittent hematochezia . on december 20 , 2015 , pet - ct demonstrated extensive metastasis .
this study reports the case of a 70-year - old male patient with advanced gastric cancer who received concurrent apatinib and local radiation therapy after failure of oxaliplatin and s-1 chemotherapy .
chemotherapy , radiation therapy , and chemoradiotherapy are recommended for metastatic gastric cancer ; however , relapses are frequent and prognosis is poor .
the recently published multinational phase iii randomized toga trial of trastuzumab , a monoclonal antibody that targets her2 , is the first to show benefit of a targeted agent in gastric cancer .
the addition of trastuzumab to a standard cisplatin / fluoropyrimidine chemotherapy doublet resulted in significant improvements in the overall response rate , pfs and os , compared to chemotherapy alone .
however , the survival benefit of trastuzumab is limited to the few patients whose esophagogastric cancers are her2 ( + + + ) or fluorescence in situ hybridization ( fish ) positive .
the gastric cancer of the patient in the current study was her2 ( + ) ; therefore , he was not eligible for trastuzumab therapy . new blood vessel formation or neovascularization is crucial for tumor growth and metastasis .
vegf binds to high - affinity receptors ( vegfr type 1 and 2 ) and leads to endothelial cell migration and proliferation .
antiangiogenesis strategies using monoclonal antibodies and tyrosine kinase inhibitors have improved os in colon , renal , non - small - cell lung cancer and hepatocellular carcinoma , and have been extensively assessed in gastric cancer .
interesting , antiangiogenesis strategies seem to be more effective in intestinal - type than diffuse - type gastric cancer .
it was the first agent to show a clear survival benefit compared with placebo in a phase iii trial in patients with advanced gastric cancer refractory to 2 or more lines of prior chemotherapy .
os was 6.5 months in the apatinib group and 4.7 months in the placebo group .
to our knowledge , the current study is the first to show that apatinib combined with radiotherapy may achieve a better clinical outcome that apatinib alone in metastatic gastric cancer .
although several trials have shown that the addition of conventionally fractionated radiation therapy to antiangiogenic agents is well tolerated , some reports suggest increased luminal gastrointestinal toxicity in combination therapy , especially when stereotactic body radiation therapy is combined with antiangiogenic agents .
however , acute radiation toxicity may selectively kill stem cells , resulting in an insufficient supply to replace sloughed villi .
furthermore , radiation therapy is associated with a decrease in vascular density , leading to ischemia , telangiectasia , and a predisposition for bleeding .
vegf plays an important role in the gastrointestinal mucosa and ulcer healing , and it may be protective against small bowel injury after irradiation .
infusion of vegf inhibitors delays healing of gastric erosions . additionally , excessive vegf inhibition can cause regression of normal blood vessels and reduced vascular density in the small intestinal villi , affecting recovery of damaged tissue .
the schedule of radiotherapy and the timing , duration , dosage and selection of vegf inhibitor may determine the extent of treatment - related toxicity . in the current study
our patient presented with intermittent gastrointestinal hemorrhage 7 months after radiation therapy ; however , gastroscopy confirmed that the hemorrhagic lesions were not radiation - associated .
however , some elderly patients with resected gastric adenocarcinoma may not gain a survival benefit from administration of adjuvant chemo radiotherapy .
the pfs of this patient reached 7 months and he experienced good quality of life .
future studies investigating treatment regimens for advanced gastric cancer should focus on target validation , the development of biomarkers of gastrointestinal toxicity , and stratify patients by age in order to better understand the impact of treatment regimens on older patients .
there is a need for more data to create treatment guidelines that can be refined to maximize treatment benefit and minimize toxicity .
elderly patients with advanced gastric cancer may benefit from concurrent apatinib and local radiation therapy when chemotherapy is not tolerated or successful .
further studies are needed to investigate the clinical outcomes and toxicities associated with concurrent apatinib and radiation therapy in gastric cancer . | ### Summary:
: abstractrationale : apatinib is a novel anti - angiogenic agent targeting vascular endothelial growth factor receptor-2 , which is effective in patients with chemotherapy - refractory gastric cancer .
there are no reports of concurrent apatinib with local radiation therapy in elderly patients with advanced gastric cancer.patient concerns and diagnoses : we present the first published report of a 70-year - old male patient with advanced gastric cancer who received concurrent apatinib and local radiation therapy after failure of oxaliplatin and s-1 chemotherapy.interventions and outcomes : the patient received concurrent apatinib and local radiation therapy and was followed up 7 months after therapy without disease progress , 14 months later indicated extensive metastasis and this patient died of pulmonary infection.lessons:elderly patients with advanced gastric cancer may benefit from concurrent apatinib with local radiation therapy when chemotherapy is not tolerated or successful .
further studies are needed to investigate the clinical outcomes and toxicities associated with concurrent apatinib and radiation therapy in gastric cancer . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: spinal anesthesia is regularly performed by anesthesiologists , as well as by obstetricians and gynecologists .
several complications of spinal anesthesia have been described , including hypotension , nausea , and vomiting 1 ; however , cardiac arrests during this procedure are very rare 2
. we present a case of unexpected cardiac arrest during spinal anesthesia in a young , healthy woman .
a 31yearold woman ( height , 136 cm , weight , 45.6 kg ) , gravida 0 , was scheduled for cervical conization due to cervical intraepithelial neoplasia 3 .
all preoperative assessments , including blood biochemistry , chest and abdominal radiography , and 12lead electrocardiogram ( ecg ) were normal .
an ecg monitor , an automated blood pressure cuff , and pulse oximetry were applied in the operating room . before spinal anesthesia ,
the patient 's blood pressure was 118/65 mmhg and heart rate ( hr ) was 58 beats / min . with the patient in the lateral position , hyperbaric bupivacaine ( 10 mg ) was injected into the subarachnoid space at the l3l4 interspace . at 5 min , maximum sensory block up to t10 was noted . in the first 15 min ,
after disinfection of the vagina in preparation for cervical conization , the patient complained of nausea .
cardiac arrest then occurred without her developing bradycardia . immediately , cardiopulmonary resuscitation ( cpr ) was initiated and epinephrine ( 1 mg ) was administered .
approximately 2 min after the initiation of cpr , sinus rhythm was restored and the patient recovered consciousness .
however , she subsequently lost consciousness again , and pulseless ventricular tachycardia ( vt ) occurred . because the patient 's ecg changed immediately from pulseless vt to cardiac arrest
, we restarted cpr and administered epinephrine ( 1 mg ) . the patient was successfully resuscitated after 2 min of cpr .
we canceled the operation and consulted cardiologists , who performed coronary angiography because the 12lead ecg after the revival of the patient showed cardiac infarction of the lateral wall ( fig 1 ) .
however , no coronary artery disease was found , and the patient was diagnosed with coronary spastic angina .
the incidence of cardiac arrest during spinal anesthesia varies from 1.3 in 10,000 to 18 in 10,000 patients 2 . according to previous reports
, young and healthy patients may experience cardiac arrest in the operating room during spinal anesthesia 3 , 4 , 5 , 6 .
unintentional total spinal anesthesia , myocardial infarction or conduction disorders , and reduction of venous return due to sudden hemorrhage or imbalance with background vagal dominance have been suggested as causative factors in previous reports 4 , 7 . in this patient , because cardiac arrest occurred in the setting of oxygen saturation readings of 99% , it is unlikely that unintentional total spinal anesthesia occurred .
baron et al . found that cardiac vagal tone is enhanced by reduced venous return 8 , and young patients typically have a strong vagal tone 7 .
thus , possible causes for cardiac arrest in this patient include a significant decrease in venous return to the heart due to the inhibition of sympathetic efferents during spinal anesthesia , enhanced vagal tone caused by a decrease in venous return , and vasovagal reflection due to nervous strain . risk factors for cardiac arrest during spinal anesthesia have been reported as follows : age < 50 years , baseline heart rate < 60 beats / min , american society of anesthesiologists ( asa ) physical status i and ii , use of beta blockers , sensory blockade above t6 level , and prolonged pr interval 7 .
pollard reported that patients may be considered at high risk for cardiac arrest during spinal anesthesia when two or more of these factors are present 7 .
the patient in the present case could be classified as having a greater tendency for cardiac arrest because she met three risk factors ( i.e. , 31 years old , baseline heart rate of 58 beats / min , and asa status i ) .
however , patients who meet two or more of the aforementioned risk factors are not uncommon .
for example , asa i or ii denotes a normal healthy patient or a patient with mild systemic disease ; therefore , many young women who are scheduled to receive spinal anesthesia for gynecological surgery or cesarean section will fall into this category .
thus , medical professionals who perform spinal anesthesia should always be aware of this possibility .
with regard to specific strategies for addressing the possibility of cardiac arrest during spinal anesthesia , the appropriateness of spinal anesthesia in highrisk patients should be evaluated carefully .
although multiple factors may lead to cardiac arrest during spinal anesthesia , evidence suggests that a decrease in venous return is one of the most important 3 , 4 , 5 , 6 , 7 , 9 .
when spinal anesthesia has been selected for a patient , maintaining an adequate preload is the key to decreasing the risk of cardiac arrest .
intravascular fluid administration of mixed and agonists has also been advocated to decrease the frequency of cardiac arrest during spinal anesthesia 7 .
furthermore , excessive anxiety and fear may cause vasovagal reflection , which applies to the present patient .
appropriate sedation might reduce this risk 9 . worsening bradycardia ( hr of 3060 beats / min )
often precedes the onset of cardiac arrest during spinal anesthesia ; intravenous administration of atropine or ephedrine has been recommended as a treatment for this condition 4 , 10 .
the effectiveness of epinephrine for cardiac arrest during spinal anesthesia has previously been reported 3 , 4 , 5 , 6 , 9 , 10 , and in our patient , the administration of epinephrine immediately after cardiac arrest restored the sinus rhythm and allowed the patient to regain consciousness .
many obstetricians and gynecologists have low exposure to perioperative cardiac arrest . in remote rural areas , cesarean section
is often carried out in a small clinic ; this necessitates that the treating physicians be prepared to deal with intraoperative complications such as cardiac arrest , which has been reported after spinal anesthesia for this procedure 3 , 9 .
although the perioperative mortality is almost 0.001% in the world 11 , the survival rate of cardiac arrest during spinal anesthesia is reported to range from 20% to 77% 12 , 13 .
cardiacarrest mortality between spinal anesthesia and other anesthesia methods in japan 14 . moreover , charuluxananan et al . 15 reported that a surgeon performing spinal anesthesia was a significant factor associated with cardiac arrest ( odds ratio , 23.5 ) .
therefore , cardiac arrest is one of the complications that obstetricians and gynecologists should be most aware of during spinal anesthesia .
we report a case of cardiac arrest during spinal anesthesia a complication that is not uncommon among young , healthy women .
obstetricians , gynecologists , and other medical professionals who perform this procedure should be aware of the potential for this complication , and be prepared to administer treatment . in the present patient ,
we conclude that when making the decision to use spinal anesthesia , judicious patient selection , adequate preventive measures , and strict monitoring are very important .
| ### Summary:
: key clinical messagespinal anesthesia is regularly performed worldwide and is an integral part of the modern day anesthesia practice .
although unexpected cardiac arrests during this procedure are very rare , medical professionals should be aware of the potential for this complication . in making the decision to use spinal anesthesia , judicious patient selection , adequate preventive measures , and strict monitoring are important . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the occurrence of manic / hypomanic switch in patients being treated with risperidone has been reported by various authors . a review of these cases , and those due to other atypical antipsychotics ( aps ) was done by michalopoulou and lykouras .
the authors described a total of 22 reported cases with risperidone induced elevated mood , and the findings brought out a few salient features of the reported cases .
the most frequently used strategy to control manic / hypomanic symptoms induced by atypical aps was the discontinuation of the agent.reduction of the dose of the atypical ap was the second most frequent strategy used.the manic / hypomanic symptoms induced by a certain atypical ap were successfully treated in several cases by another atypical ap.in three risperidone treated cases the hypomanic symptomatology of the patients was self - limited and resolved without alternation of risperidone dose or the addition of any other medication .
the hypomanic symptomatology in these cases was thought to be a transient paradoxical behavioural response during the 1 days or weeks of treatment.the dose of risperidone was not altered and valproate was added to control the manic symptoms in two cases.when dose of the atypical ap that induced the manic / hypomanic symptoms was increased to control them , the management of the symptoms was unsuccessfulin case of risperidone treated patients , time until remission of the manic / hypomanic symptoms ranged from 36 h to 2 monthsthe rapid remission of manic / hypomanic symptoms that was observed in three risperidone treated cases after discontinuation of the atypical ap suggested that these symptoms might be the direct effect of the compound .
the most frequently used strategy to control manic / hypomanic symptoms induced by atypical aps was the discontinuation of the agent .
reduction of the dose of the atypical ap was the second most frequent strategy used .
the manic / hypomanic symptoms induced by a certain atypical ap were successfully treated in several cases by another atypical ap . in three risperidone treated cases the hypomanic symptomatology of the patients was self - limited and resolved without alternation of risperidone dose or the addition of any other medication .
the hypomanic symptomatology in these cases was thought to be a transient paradoxical behavioural response during the 1 days or weeks of treatment .
the dose of risperidone was not altered and valproate was added to control the manic symptoms in two cases . when dose of the atypical ap that induced the manic / hypomanic symptoms was increased to control them , the management of the symptoms was unsuccessful in case of risperidone treated patients , time until remission of the manic / hypomanic symptoms ranged from 36 h to 2 months
the rapid remission of manic / hypomanic symptoms that was observed in three risperidone treated cases after discontinuation of the atypical ap suggested that these symptoms might be the direct effect of the compound .
we present here , two case reports of induction of elevated mood symptoms in patients treated with risperidone , and then discuss a few findings that might be useful in the management of such cases .
a 30-year - old married , hindu , male , a farmer by profession from the rural part of eastern india , with no significant family , past or personal history .
he had a well - adjusted pre - morbid personality and gave an account of harmful use of tobacco .
he presented to the out patient department of the institute with an illness of 1.5 years duration with insidious onset , a continuous course and deteriorating symptoms characterized by decreased social interaction , abusive and assaultive behavior , muttering and smiling to self , suspiciousness , wandering tendency , and decreased sleep . during the time of admission ,
on mental status examination , the patient had inadequate eye contact , withdrawn manner of relating , inappropriate smiling , and constantly muttering to self .
he harbored a delusion of persecution and experienced 3 person auditory hallucinations of running commentary type , with derogatory content .
the patient was provisionally diagnosed according to international classification of diseases ( icd-10 ) to have undifferentiated schizophrenia .
he was started on risperidone 3 mg , which was hiked to 6 mg in 3 days .
five days following the initiation of risperidone , the patient developed euphoric affect , which was appropriate and communicable , inflated self - esteem and 2 person auditory hallucinations with grandiose content .
no other drug side - effects were noted . score on young 's mania rating scale ( ymrs ) was 21 . in order to control the mood symptoms ,
carbamazepine 400 mg was added to the drug regime , which was gradually , hiked up to 800 mg .
four days after reaching the dose of 800 mg carbamazepine , the ymrs score came down to 15 .
risperidone was then hiked to 8 mg . on 8 mg risperidone and 800 mg carbamazepine , the thought and
the patient was discharged after 1 month of admission , on request from the guardian , on 800 mg of carbamazepine , 8 mg risperidone and 4 mg trihexyphenidyl . at the time of discharge ,
the ymrs score was 13 . on follow - up after 1 month , patient was asymptomatic with cheerful affect , no thought / perceptual abnormality and ymrs score of 7 .
k.a . , a 55-year - old married , muslim , male from urban part of eastern india belonging to middle socio - economic class , with history of intake of tobacco , harmful use and nil contributory family history ; presented with an illness of abrupt onset , continuous course and deteriorating progress of 6 days duration characterized by wandering tendency , crying spells , low mood , decreased interest , decreased sleep , fearfulness and increased talkativeness , following a stressor prior to the onset of the illness .
on mental status examination , there was a fearful facial expression , fidgety behavior , increased speech productivity mostly concerned with the content of his fearfulness , a communicable dysphoric affect , and delusion of persecution and reference .
the patient was diagnosed as a case of acute and transient psychotic disorder without symptoms of schizophrenia , according to the icd-10 .
he was started on 900 mg of lithium carbonate ( in view of mood instability ) and risperidone 2 mg that was increased gradually to 4 mg ( hiked 1 mg every 3 days ) . on 900 mg of lithium carbonate ,
seven days after admission , the patient developed elated affect , overfamiliar attitude , inflated self - esteem ; with a complete resolution of the delusions of persecution and reference .
after 3 more days , in addition , there was an increase in his goal directed activities and an unfounded optimism .
two days following this , lithium carbonate was hiked to 1200 mg and risperidone was hiked to 6 mg . with this , the over familiarity and hyperactivity improved .
the patient was discharged after 20 days on request by the guardian ; on 1200 lithium carbonate and 7 mg risperidone . on follow - up after 1 month , serum lithium level was 0.76
a 30-year - old married , hindu , male , a farmer by profession from the rural part of eastern india , with no significant family , past or personal history .
he had a well - adjusted pre - morbid personality and gave an account of harmful use of tobacco .
he presented to the out patient department of the institute with an illness of 1.5 years duration with insidious onset , a continuous course and deteriorating symptoms characterized by decreased social interaction , abusive and assaultive behavior , muttering and smiling to self , suspiciousness , wandering tendency , and decreased sleep . during the time of admission ,
on mental status examination , the patient had inadequate eye contact , withdrawn manner of relating , inappropriate smiling , and constantly muttering to self .
he harbored a delusion of persecution and experienced 3 person auditory hallucinations of running commentary type , with derogatory content .
the patient was provisionally diagnosed according to international classification of diseases ( icd-10 ) to have undifferentiated schizophrenia .
he was started on risperidone 3 mg , which was hiked to 6 mg in 3 days .
five days following the initiation of risperidone , the patient developed euphoric affect , which was appropriate and communicable , inflated self - esteem and 2 person auditory hallucinations with grandiose content .
no other drug side - effects were noted . score on young 's mania rating scale ( ymrs ) was 21 . in order to control the mood symptoms ,
carbamazepine 400 mg was added to the drug regime , which was gradually , hiked up to 800 mg .
four days after reaching the dose of 800 mg carbamazepine , the ymrs score came down to 15 .
risperidone was then hiked to 8 mg . on 8 mg risperidone and 800 mg carbamazepine , the thought and
the patient was discharged after 1 month of admission , on request from the guardian , on 800 mg of carbamazepine , 8 mg risperidone and 4 mg trihexyphenidyl . at the time of discharge ,
the ymrs score was 13 . on follow - up after 1 month , patient was asymptomatic with cheerful affect , no thought / perceptual abnormality and ymrs score of 7 .
mr . k.a . , a 55-year - old married , muslim , male from urban part of eastern india belonging to middle socio - economic class , with history of intake of tobacco , harmful use and nil contributory family history ; presented with an illness of abrupt onset , continuous course and deteriorating progress of 6 days duration characterized by wandering tendency , crying spells , low mood , decreased interest , decreased sleep , fearfulness and increased talkativeness , following a stressor prior to the onset of the illness .
the physical examination findings were unremarkable . on mental status examination , there was a fearful facial expression , fidgety behavior , increased speech productivity mostly concerned with the content of his fearfulness , a communicable dysphoric affect , and delusion of persecution and reference .
the patient was diagnosed as a case of acute and transient psychotic disorder without symptoms of schizophrenia , according to the icd-10 .
he was started on 900 mg of lithium carbonate ( in view of mood instability ) and risperidone 2 mg that was increased gradually to 4 mg ( hiked 1 mg every 3 days ) . on 900 mg of lithium carbonate ,
seven days after admission , the patient developed elated affect , overfamiliar attitude , inflated self - esteem ; with a complete resolution of the delusions of persecution and reference .
after 3 more days , in addition , there was an increase in his goal directed activities and an unfounded optimism .
two days following this , lithium carbonate was hiked to 1200 mg and risperidone was hiked to 6 mg . with this , the over familiarity and hyperactivity improved .
the patient was discharged after 20 days on request by the guardian ; on 1200 lithium carbonate and 7 mg risperidone . on follow - up after 1 month , serum lithium level was 0.76
clozapine , the prototype of atypical aps , demonstrates a higher affinity for 5ht-2a receptors than for the d2 receptors .
risperidone , olanzapine , quetiapine and ziprasidone also share this property with clozapine and are therefore considered to be serotonin - dopamine antagonists ( sdas ) .
adjunctive atypical ap therapy appears to benefit patients experiencing manic episodes in the course of bipolar and schizoaffective disorder .
their role in the maintenance phase of treatment of bipolar and schizoaffective disorder as an adjunct to mood stabilizers or as mono - therapy has also been explored .
further , there is accumulating evidence , though still limited , that patients with non - psychotic treatment resistant depression may benefit from the combination of atypical aps with ( selective ) serotonin reuptake inhibitors ( [ s ] sris ) .
it has been suggested that the synergistic effects of atypical aps in combination with ( s ) sris on dopamine and norepinephrine release in the prefrontal cortex may contribute to their ability to augment the antidepressant effect in patients suffering from treatment resistant depression .
it has been suggested that the mood altering effects of the atypical aps are dose dependent , with lower doses resulting in the enhancement of forebrain dopaminergic activity via mechanisms that will be discussed below .
combined 5ht-2a and d2 antagonism , especially the relative higher affinity for 5ht-2a than d2 receptors is characteristic of sdas .
it has been suggested that the mood altering effects of risperidone result from its high 5ht-2a receptor affinity , as a function of the 5ht-2a / d2 occupancy ratio .
indeed , low doses of risperidone are associated with relatively higher 5ht-2a occupancy that can result in enhancement of forebrain dopaminergic activity by disinhibition of the dopaminergic system , influencing the mood state . at higher doses
, however , the saturation of the 5ht-2a receptors and the increasing d2 occupancy counteracts this action of the associated 5ht-2a activity .
it has also been suggested that the combined 5ht-2a and d2 receptor blockade of the sdas increases dopamine release in the prefrontal cortex - at least partly - via 5ht-1a receptor activation , regardless of intrinsic 5ht-1a affinity .
the atypical aps appear to be involved in the induction of manic / hypomanic symptoms in susceptible individuals not only through a dose dependent discriminant activation of 5ht-2a and d2 receptors , but also through their 5ht-1a receptor activity .
the occurrence of amisulpride - induced mania - a non - sda atypical ap - may suggest that the enhancement of the frontal dopaminergic transmission and the subsequent mood alternation is not necessarily associated with combined 5ht-2a and d2 receptor antagonism .
it is possible that other mechanisms , which are not necessarily dose related , are also involved in the induction of manic / hypomanic symptoms in susceptible individuals .
we believe that the emergence of these symptoms may be a complication of treatment with drugs in susceptible individuals .
clinicians should be aware of the possibility of mood switching effects of these medications in susceptible individuals .
combined 5ht-2a and d2 antagonism , especially the relative higher affinity for 5ht-2a than d2 receptors is characteristic of sdas .
it has been suggested that the mood altering effects of risperidone result from its high 5ht-2a receptor affinity , as a function of the 5ht-2a / d2 occupancy ratio .
indeed , low doses of risperidone are associated with relatively higher 5ht-2a occupancy that can result in enhancement of forebrain dopaminergic activity by disinhibition of the dopaminergic system , influencing the mood state . at higher doses
, however , the saturation of the 5ht-2a receptors and the increasing d2 occupancy counteracts this action of the associated 5ht-2a activity .
it has also been suggested that the combined 5ht-2a and d2 receptor blockade of the sdas increases dopamine release in the prefrontal cortex - at least partly - via 5ht-1a receptor activation , regardless of intrinsic 5ht-1a affinity .
the atypical aps appear to be involved in the induction of manic / hypomanic symptoms in susceptible individuals not only through a dose dependent discriminant activation of 5ht-2a and d2 receptors , but also through their 5ht-1a receptor activity .
the occurrence of amisulpride - induced mania - a non - sda atypical ap - may suggest that the enhancement of the frontal dopaminergic transmission and the subsequent mood alternation is not necessarily associated with combined 5ht-2a and d2 receptor antagonism .
it is possible that other mechanisms , which are not necessarily dose related , are also involved in the induction of manic / hypomanic symptoms in susceptible individuals .
we believe that the emergence of these symptoms may be a complication of treatment with drugs in susceptible individuals .
clinicians should be aware of the possibility of mood switching effects of these medications in susceptible individuals . | ### Summary:
: the occurrence of manic / hypomanic switch in patients being treated with risperidone has been reported by various authors , and they have described a variety of strategies for their management . in this report , we describe two cases of induction of elevated mood symptoms in patients treated with risperidone .
we propose that the emergence of these symptoms may be a complication of treatment with this drug in susceptible individuals , of which the clinicians should be aware , mainly in those diagnosed with schizophrenia and bipolar disorder .
we then discuss a few findings that might be useful in the management of such cases .
we thereby also propose a mechanism for such an induction . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: cancer has significant traumatic effects on the family members of the patients , particularly in asia 's tightly knitted families .
cancer is debilitating because , by itself , it threatens the health , structure , and dynamics of human beings . despite current advances in cancer treatment ,
even the most potent cancer treatments often bring debilitating physical , psychosocial , and emotional side effects in the family members .
it is normal for families facing cancer to be upset and worried about this crisis .
families with young children or adolescents are often concerned about how children will react to cancer in a family member .
adolescents may be more at risk than younger children for becoming distressed , as they are old enough to be aware of and understand what the parent is going through and the existential issues that may arise .
between 20 and 32% of adolescent boys and girls were reported to have experienced clinically elevated levels of emotional and behavioral problems throughout the first year after a parent was diagnosed with cancer .
confrontation with parental cancer can be highly threatening for children and may result in the development of psychosocial problems such as anxiety , confusion , sadness , anger , and feelings of uncertainty with respect to the outcome of the illness .
they may face many changes in daily family routine due to repeated hospital admissions , hospital visits , and care of the parent when at home .
adolescents whose parents are ill may manifest their distress through changes in school performance , physical complaints of pain and discomfort , as well as changes in social and interpersonal relations .
adolescents , in general , are under constant pressure , striving for independence and for a separate identity , and express feelings of conflict between the wish to break away from the family origin versus the reality that they need at home both emotionally and physically .
therefore , adolescents may experience many changes in their quality of life . according to research
, cancer affects the quality of life of the family members of the patients in five major areas : emotional , social , physical , spiritual , and financial .
quality of life is a matter of importance for health care professionals and policy makers .
quality of life assessment can help to facilitate communication with clients and identification of their preferences , for example , to select a specific treatment or plan .
some researches have been conducted in the field of the effects of cancer , especially advanced cancer , on the psychological aspects of children living with them and a few studies in the field of quality of life of adolescents living with parents with cancer , but there has not been any study conducted in our country so far .
therefore , the researchers decided to assess this issue and they planned to evaluate the effects of their proposed program on the aspects of quality of life of these adolescents .
the present study was a quasi - experimental , one - group study with a pre - test post - test design , which was conducted in esfahan , from march up to october 2014 .
pre - test post - test designs are widely used in behavioral research , primarily for the purpose of comparing groups and/or measuring changes resulting from experimental treatments .
the sample of this study consisted of 30 adolescents in the age group 1120 , without a history of any major disease , and who were living with a parent with cancer at the first year of diagnosis and the parent was at the stage of chemotherapy or radiation therapy , with no metastasis of this cancer .
these adolescents were selected from two main special cancer centers , one cancer clinic , and one oncologist 's clinic in esfahan .
the exclusion criterion was the unwillingness of subjects at any time of research . to attain this sample size , during 6 months
, the researchers spoke to 113 patients with cancer who had referred to the centers of collecting samples , leaving their adolescent children at home ; only 43 of them allowed their children to join the research and of these 43 adolescents , 30 adolescents completed both pre - test and post - test questionnaires ( response rate 69.76% ) .
all the parents and adolescents were given verbal and written information about the purpose and importance of the study .
written , informed consent was obtained from the adult participants and from the parents of adolescents before they completed the first questionnaire and they were free to withdraw from the study at any time . the data gathering tool was the iranian translation of the short form of quality of life questionnaire ( sf-36 ) .
this questionnaire has been used many times in iranian 's researches and was found to have a good validity and reliability .
all the questions are scored on a scale from 0 to 100 , with 100 representing the highest level of functioning possible . besides this questionnaire
, we used demographics questionnaire that contained questions about sex , age , types of parent 's cancer , birthrate , and if there was any special disease in the adolescent participant .
the questionnaire was completed at the hospitals , clinics , or adolescents home before and 1 month after presenting supportive - educative program .
all the subjects completed the pre - test questionnaire at the two major oncology hospitals , clinics , or adolescents home separately .
the supportive - educative program was presented individually at the home of adolescents or in a small group using lecturing methods at the hospitals depending upon adolescents preference . according to the educational content of the program
, this scheme was presented in at least two sessions up to four sessions , depending upon the adolescents needs .
each session lasted about 4590 min and the sessions were presented during 1 month . for the children who were taught at home , we used face to face instruction .
the parents were not present in the in the first session of the education program , but if it was noticed that it was necessary to explain some items in their presence , they were asked to take part in the second or third session .
some of the adolescents had come to the hospital with their parents , so we decided to have a group discussion with them during their parent 's treatment .
four adolescents had corporated in the group discussion . in the first session , after completing the pre - test questionnaire , we wanted them to explain their experiences to the group members ; through this , they came to know that their feelings were the same as others .
the second session was conducted following their parent 's treatment and all the four adolescents were present in this session . in the second session , we explained the other aspects of living with a cancer parent to them .
after 1 month , the post - test questionnaire was completed at the adolescents home or by calling one of them to complete the questionnaire .
thus , the pre - test and post - test interval was 2 months for all the subjects .
supportive - educative program was extracted from some references , similar programs , and by consulting the oncologist and onco - psychologist and oncology nurses . a booklet and compact disc of this program
was given to the adolescents after the education , and also , a weblog ( www.zendegi-ba-saratan.blogfa.com ) that was designed by the researchers was introduced to them where they could access further information . at this weblog
, we presented a lot of information about cancer , types of cancer , treatment of cancer , prognosis and managing cancer , living with a cancer parent , coping with cancer , its complications , and also confronting with death .
descriptive statistics like frequency , mean , and standard deviation , and also paired sample t - test were used for analyzing data by spss ( ver 16 ) software of international business machines corporation ( ibm)and the significance level of p value was 0.05 .
the findings of this study showed the following : the subjects were in the age group 1120 , most of them were girls , school students , and the birthrate of them was from one to six [ table 1 ] .
demographic characteristics of the subjects paired sample t - test showed that before and after presenting the program , there were no statistical differences between role limitation due to physical health and role limitation due to emotional problems , but there were significant statistical differences between physical functioning , energy / fatigue , emotional well - being , social functioning , pain , general health , the subcategory of physical health , and the subcategory of psychological health [ table 2 ] . paired t - test between aspects of quality of life before and after presenting the program the findings also showed that before presenting the program , there were significant statistical differences in general health ( p = 0.024 ) by knowledge and general health by birthrate ( p = 0.018 ) and after presenting the program , significant differences were found in social functioning ( p = 0.011 ) and the subcategory of psychological health ( p = 0.035 ) by sex , and energy / fatigue ( p = 0.016 ) , emotional well - being ( p = 0.006 ) , social functioning ( p = 0.001 ) , general health ( p = 0.014 ) , the subcategory of physical health ( p = 0.010 ) , and the subcategory of psychological health ( p = 0.001 ) by knowledge . before presenting the program , the subcategory of psychological health ( p = 0.049 ) and after presenting the program , the subcategories of physical health ( p = 0.002 ) and psychological health ( p = 0.004 ) had significant statistical differences by knowledge .
the present study is the first project in iran that directs attentions toward the effects of supportive - educative program on the quality of life in adolescents whose parents were diagnosed with cancer during the last year .
the main goal of the study was to investigate the quality of life of adolescents before and after presenting the program .
the results showed that before presenting the program , the quality of life scores of adolescents in many aspects like physical functioning , role limitation due to physical health , role limitation due to emotional problems , and pain were in good range and near 100 .
this finding that families with a parent with cancer may experience more positive family functioning than normal families had been noticed in some other researches also , thus supporting our research .
in some aspects like energy / fatigue , the score of samples was about 56 and in emotional well - being , it was about 57 , which were in the middle range .
huang and colleagues ( 2014 ) stated , many children described reduced energy , emotional vulnerability and negative behaviors of the ill parents , which is in line with our findings , but contrast to the reports of gazendam - donofrio et al . and ainuddin et al . , where they had not noticed a decrease in adolescents emotional functioning .
in iran , the structure of families is very tightly knitted ; therefore , when one of the members in a family confronts a disease , other members pay more attention to the patient and to each other as well .
this might be the main reason why there is more positive functioning in many aspects , and perhaps for this special reason , we had not noticed apparent changes before presenting our program . on the other hand , because of this special care and uneasiness , their stress , fear about the disease , its treatments , complications , and its prognosis would increase and the adolescents would experience many problems , and consequently , this will have serious effects on some aspects of their quality of life such as like emotional well - being and energy / fatigue .
our findings showed that there were no differences between age , sex , knowledge , birthrate , and the subcategories of physical health and psychological health before presenting the program .
this is contrary to some other researches in which it was asserted that quality of life of female adolescents was more affected than that of male adolescents .
of course keeping in view the small sample of this research , this finding should be considered cautiously and supported by other studies with larger sample size .
the results showed that after presenting the program , all aspects of quality of life had an increase in scores , and in many aspects , this increase showed significant statistical differences .
visser et al . , in a review of literature , stated that intervention studies were aimed to help family members to communicate more openly with each other and to increase their coping strategies .
all papers reported positive effects of the interventions , including less anxiety and more open communication . since our supportive - educative program emphasized on open communication and coping strategies in families facing cancer , this might the reason for the increase in scores of quality of life , although the elapse of time and increased coping of adolescents with their parents cancer could be some other reasons .
the finding that the level of education of adolescents could be a factor accounting for the differences in the subcategories of physical and psychological health has not been mentioned in other researches .
the limitation of this study , which did not affect its main findings but had a bearing on how they are interpreted , that needs to be taken into account is that many parents were afraid of the emotional distress of their adolescents , or believed that the effects of cancer were small because minimal treatment was needed .
some others mentioned that their adolescent children were not informed about the diagnosis and did not let them participate in this research .
therefore , the sample size was limited and the findings had minimum value for generalization to all adolescents living with a parent with cancer .
also , our small sample might have been one of the reasons affecting the results . on the other hand ,
the differences between samples in economic , social , and cultural aspects might have been the other limitations that could not be controlled by the research team .
the present results may heighten the awareness of health care providers that parental cancer may affect adolescents who live with them and the major problem of these adolescents is change in quality of life . since references asserted that open communication between adolescents and their family and increasing coping strategies in adolescents can enhance the aspects of quality of life and our program had special emphasis on these issues , health care providers , especially nurses who are often well placed to initiate and facilitate the process of meeting these needs , should present these issues to the adolescents . the results of this study also showed that we need some special places in our hospitals for educating and supporting the adolescents who accompany their parents for their treatments , and also we need a planned program and special nurses for this in our cancer hospitals .
adolescents who live with parents with cancer have many problems in their quality of life aspects ; therefore , their parents must know about this and they should be educated about the ways that they can encounter this problem and help their children . of course , more studies are needed to investigate the effects of different programs for these adolescents , and this study can be used as a basic research for nurses or other health professionals for further researches . | ### Summary:
: background : cancer has significant traumatic effects on the family members of the patients , particularly in asia 's tightly knitted families .
research evidence suggests a debilitating impact of cancer on the quality of life of the afflicted individuals , their spouses , and their families .
since a few studies have been carried out on the quality of life of adolescents living with parents diagnosed with cancer , especially in iran , the research team decided to evaluate the quality of life of them and also investigate the effects of supportive - educative program on it.materials and methods : the present quasi - experimental , one - group study had a pre - test post - test design and was performed in esfahan in 2014 .
the sample of this study consisted of 30 adolescents .
the data gathering tool was the short form of quality of life questionnaire ( sf-36 ) .
data were analyzed by descriptive statistics and paired sample t - test .
p - value of 0.05 was considered significant.results:the paired sample t - test showed that before and after presenting the program , there were significant statistical differences in some aspects of quality of life , such as physical functioning ( p = 0.01 ) , energy / fatigue ( p < 0.0001 ) , emotional well - being ( p < 0.0001 ) , social functioning ( p = 0.001 ) , pain ( p < 0.0001 ) , and general health ( p = 0.01).conclusions : this research showed that supportive - educative program can enhance some aspects of quality of life .
therefore , nurses and other health professionals can use this scheme or similar programs for helping adolescents living with a parent with cancer . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the family as an integrated and functional unit of society has for a considerable period of time captured the attention and imagination of researchers . while the family itself is a matter of study , equally important for research is its role as a factor influencing and affecting the development , behavior , and well - being of the individual .
the family is a basic unit of study in many social science disciplines , such as sociology , psychology , economics , anthropology , social psychiatry , and social work .
it is also a unit of study in the medical sciences especially in understanding the epidemiology and the natural history of diseases .
census definitions of family have varied from country to country and also from census to census within country .
the word household has often been used as a replacement for family . using the definition as all people living in one household may be erroneous , as on one hand it may include people who do not share kinship , and on other hand may exclude those kin members who are temporarily away .
this type of definition fails to identify units that function as families in an economic , social or emotional sense but do not usually reside in the same household .
although the literature often focuses on family living arrangements , family membership includes obligations across and between generations , no matter where family members are living .
the unesco report stated that a family is a kinship unit and that even when its members do not share a common household , the unit may exist as a social reality .
this definition may be too broad to serve the purpose of identification of a family unit for the purpose of assessment as a factor in variables such as health .
just to give an example , a family in a developing country has a son living in the usa , happily married there with a wife , and he sends across some money to the other family members back home occasionally and visits the country once in many years .
does this person ( and his wife ) share the same risks to their immediate health as the other family members back in the shared household ? would this individual and his dependants in the new surroundings have access to the same kind of health care options as the other family members living in the country of birth ? and would the offspring of this person born in the foreign country experience the same sociocultural and environmental exposures , as ( s)he would have come into contact with growing up in the country of origin ?
trask observed that while in the past , locale mattered , today social relationships are maintained over great distances with ease .
global communications such as the internet , e - mail , and satellite linkups are facilitating these relationships over space and time .
still , keeping in mind the previous pertinent questions that are raised if we want to consider the family as a factor influencing and interacting with other variable characteristics ( such as health , environment , social behavior , etc . ) , the scales are still tilted toward defining the family as people ordinarily sharing a common living area .
the meaning of the term family also depends on whether it is being interpreted in a social , biological , cultural , or statistical sense .
it is important to identify a family unit and the members constituting the unit , for the purpose of studying their health , for example .
desai ( 1994 ) , as cited in sonawat defined the family as a unit of two or more persons united by marriage , blood , adoption , or consensual union , in general consulting a single household , interacting and communicating with each other .
while the definition is mostly fine , the interacting and communicating with each other may be a difficult thing to elicit or determine .
an existing textbook of the medical specialty of community medicine makes it more objective by defining the interdependence part as individuals living together and eating from a common kitchen .
it considers and defines three types of families : nuclear , joint , and three generation families .
however , practical experience in community has shown that these categories are not mutually exhaustive .
for example , the protection of women from domestic violence act , 2005 of india recognizes and provides protection to female living in a relationship in the nature of a marriage with a male partner .
family research provides insight into the structure of society and the changes taking place in the types , composition , and growth of families .
families can be classified in several different dimensions , for example , by marriage type ( monogamous , polygamous ) , by location ( patrilocal , matrilocal , and avunculocal ) , authority ( patriarchy , matriarchy ) , and by kin composition ( nuclear , joint ) . in the present new classification ,
adjectives can be added to define the family as per marriage type or by locus of residence or authority . in a social sense
people may see themselves as being members of several families , as members of families with their parents and siblings and also members of families that they have formed themselves .
however , in the current proposed classification for the purpose of family , the view is that an individual will in usual circumstance belong to one family only in a given role . because of the multitude of definitions of family and the changing realities of the current times
, there is a felt need for redefining the family and the common types , for the purpose of study of the family as a factor in health and other variables of interest . the following definition of a
family is hence proposed : people related by marriage , birth , consanguinity or legal adoption , who share a common kitchen and financial resources on a regular basis .
the family will comprise of people ordinarily living in the same house , unless work , study , imprisonment , confinement , foreign sojourn , or any other exigencies compel a member to temporarily live away from the shared house .
members living away from the physical premises of the shared house , who are not expected to return back to living in the house in the future , will also cease to be considered as members of this family , even though they may be sharing financial resources .
common kitchen does not only mean just sharing of a physical infrastructure of a kitchen , but also sharing of common cooked meals in the kitchen . in such families where sets of members share the kitchen together but do not share financial resources , and those where sets of members share financial resources but do not share the kitchen together , the different sets of members should be counted as different families .
regarding common financial resources of the family , it is the sharing that is more important than contributing
. an unmarried relative may be there who is not earning and thus not contributing economically to the family purse , but will be counted toward the family if ( s)he is sharing the family financial resources .
the term on a regular basis in the definition , is left open - ended deliberately . in some families , people may have had tiffs and stopped sharing food together for a period of time that may be few days , few weeks , or few months . after what period of time do we say that they stop comprising a single family ?
similar dilemma is there for a time period cutoff regarding nonsharing of financial resources . and
a very important aspect in this decision would be future intent , that is , whether the constituents think the differences are irrevocable or they think the possibility of getting together is there , whatever may be the period of nonsharing thus far . in case of any doubt , it is best left to a subjective assessment of the individual family unit at hand .
the researcher may directly ask the constituents whether they still consider themselves as belonging to a single common family or not .
it has been noted earlier that family membership and obligations are subjective and can only be fully understood from the perspective of the family concerned .
a student who goes to reside in any other city for few years of education and stays in a hostel , with guardians , or in a private accommodation , does not cease to be a part of the original family for those years , only because ( s)he is not sharing the family 's common kitchen .
however , to be counted as a member of the original family , ( s)he must continue to share in or receive money or other things of monetary value from the financial resource pool of the family . one important caveat would be that the individual must have the intent of returning to the original family in the future , unless compelled by needs of higher studies or job
. another case may be of a young adult member of the family who has gone abroad for work , or who went abroad for higher education and ends up finding a vocation there .
such a person may visit back on rare occasions to his or her family of origin , but is reasonably expecting to be staying put in the new location for the foreseeable future .
such a member would not then be exposed to the risk factors or the protective social factors common to the other members sharing a residence .
so this person should be counted as belonging to a separate new family , irrespective of whether ( s)he has married and irrespective of sharing of financial resources with the original family back home .
biologically unrelated individuals living together in an institutional setting , for example , hostel , boarding school , working women 's hostel , and so on , or living together in a single house , will be counted as belonging to their family of origin or as separate family units ( single individual families ) as the case may be depending on their future intent .
they will not be combined or considered together to form new family units . a person imprisoned for a known period of time does not cease to be a member of the original family ( unless legally disowned by the head of the family , or by the next head of the family if ( s)he happens to be the head ) .
this is because the person is expected to have the intent of returning to the original family unit as soon as the period of confinement is over .
a new classification scheme for the various types of family structure is being proposed , keeping in mind the redefined family .
the various types of family under the proposed classification scheme are detailed in the table 1 .
the first step was to define the various types of family possible , which will cover the myriad variations possible in the current times . then came the question of coming up with suitable terms to label the categories of family types , and it was thought of to come up with a uniform terminology scheme - based on the classic terms .
the proposed classification of types of family the word nuclear was picked upon , that represents a married couple as forming the nucleus of a family , as per existing classifications of family structure .
terms from the atomic world were explored to extend the analogies to the family structure types .
electrons would be something outside the nucleus , that is , a married couple ( nucleus ) is not there .
two nuclei can not be there in an atom , it would have to be a molecule .
it may be clarified here that terms from physics were chosen here just for the nomenclature of the proposed family types .
use of these terms borrowed from physics is expected to aid in easier appreciation and recall of the various family types .
the classic term of joint family has been retained to define the complex sharing of resources by multiple couples .
however , the traditional joint family has also been redefined and has two different meanings depending on the number of generations present . generally across various cultures , obligations to siblings
this is the reason why the proposed definition of joint family considers different number of couples , depending on the number of generations involved .
two married brothers ( or two sisters ) living together with their respective families would qualify to be termed as a joint family .
it is a difficult task to categorize families according to any theoretical type or to generalize across or within cultures .
an endeavor has been made to try to redefine the family as well as the types of family to keep up with the changing times . however , as per practical experience , the community throws up scenarios which may test any theoretical model of classification . keeping this in mind ,
an exercise was done to contemplate a few exceptional case scenarios and discuss their classification as per the new model , in a bid to clarify the classification scheme further [ table 2 ] .
a paper on the structure of families in new zealand over time has observed that the family is constantly changing and diversifying there .
same - sex couples have been included in the data , but they can be identified as subsets of couple - only and two parent families .
certain types of family that are becoming more prevalent there include one - parent families and couple - only families . as per the new classification ,
these types of families can be identified as ii - electron and iii - nuclear family , respectively .
the situation of a family with a married couple only and no children can be termed as a nuclear couple family , but it should be classified as a subtype of the nuclear family only and not as a separate type .
similarly , the sole - parent family can be identified as a subtype of an electron family ( type ii ) . unlike a previous definition given by desai , as cited in sonawat , relationship by consensual union has not been taken as one of the criteria for defining the family , in the basic definition proposed . as mentioned earlier
domestic relationships in the nature of marriage , but the legal and social positions are still evolving .
however , in view of the social realities , a classification for families based upon such nuclear relationships has been put forward with the use of qualifier quasi- ( type vii ) .
elliott and gray have also discussed the gray zone caused by remarriage families ( or blended families as they term it ) in classification of families .
there may be differences in both the emotional and financial support given to children between natural and new parents .
also , for many children , both their natural parents may play a very real part in their lives even if they do not live in the same household .
but , counting an individual ( e.g. , the separated natural father / mother ) in more than one family may lead to factual mismatches and also create lot of confusion .
it is best to consider the remarriage family too as within the frame of the seven types of family set in the new classification , and to label them as a subtype remarriage family if required .
the family surroundings affect the health of an individual in several ways . members of a family can be expected to share the risk factors for their health that may arise from various social characteristics of their shared housing , neighborhood , community , society , and culture .
all the members of a family living together who share the financial resources of the family unit would also share the risks of ill - health and costs of health care as well as the protection offered by availability of money with the family to tide over health - related issues .
living in a family would also mean usually exposure to similar dietary behaviors and health - related lifestyles , among the family members .
the changing dynamics of family composition can have important impact on the protective as well as risk factors influencing health .
thus , an updated definition and classification scheme for types of families serves an important purpose for the practitioners of various medical and social science disciplines in the current times .
members of a family can be expected to share the risk factors for their health that may arise from various social characteristics of their shared housing , neighborhood , community , society , and culture .
all the members of a family living together who share the financial resources of the family unit would also share the risks of ill - health and costs of health care as well as the protection offered by availability of money with the family to tide over health - related issues .
living in a family would also mean usually exposure to similar dietary behaviors and health - related lifestyles , among the family members .
the changing dynamics of family composition can have important impact on the protective as well as risk factors influencing health .
thus , an updated definition and classification scheme for types of families serves an important purpose for the practitioners of various medical and social science disciplines in the current times .
it is to be expected that the changing societal arrangements in the current times will be a huge challenge for any model of classification of family structure . on top of that is the challenge to keep the possible classification groups to the minimum possible , so that analysis of the family structure as a factor in health and other outcomes , in future studies , does not become an inordinately complex exercise . this is a proposed redefinition of family and a proposed scheme of classification of family structure , to try to match the pace of change of current societies .
while the objective was mainly to redefine keeping the indian cultural environment in mind , the sheer heterogeneity of the indian population in terms of sociocultural milieu is immense .
the current proposed scheme should generally suffice for use in other countries and cultures , for broadly classifying the family structure .
the intricacies and unique scenarios of particular cultures can be taken into account by defining region or culture - specific subtypes of the overall types of family structure defined in the present article . | ### Summary:
: the family is a basic unit of study in many medical and social science disciplines .
definitions of family have varied from country to country , and also within country .
because of this and the changing realities of the current times , there is a felt need for redefining the family and the common family structure types , for the purpose of study of the family as a factor in health and other variables of interest . a redefinition of a
family has been proposed and various nuances of the definition are also discussed in detail . a classification scheme for the various types of family has also been put forward .
a few exceptional case scenarios have been envisaged and their classification as per the new scheme is discussed , in a bid to clarify the classification scheme further .
the proposed scheme should prove to be of use across various countries and cultures , for broadly classifying the family structure .
the unique scenarios of particular cultures can be taken into account by defining region or culture - specific subtypes of the overall types of family structure . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: n.e.u.r.o.n . strives to provide an open forum for undergraduate students and faculty with similar interests in neuroscience . n.e.u.r.o.n .
also provides faculty with an opportunity to discuss curricular and research issues in neuroscience , biopsychology , and other related scientific areas . through the annual conference , n.e.u.r.o.n . enhances communication and collaboration among neuroscience researchers and educators .
conference that provides a forum for undergraduate and graduate students to present their research and gain feedback from peers and faculty on research in which they are engaged during the academic year .
the conference includes workshops that discuss important topical and pipeline neuroscience issues , top speakers who give keynotes on current topics in neuroscience , and a poster session that provides students with an opportunity to share their research with others .
the diversity of this agenda provides an opportunity for all attendees to engage in science , while promoting and encouraging the development of neuroscience training .
this meeting is unique as the nurturance of neuroscientists in training is the sole focus of the meeting . towards this end
, a secondary goal of the meeting is to provide a forum for educators to come together for discussions of how to improve neuroscience training . n.e.u.r.o.n .
provides excellent opportunities for collaboration ( research and pedagogy ) between the faculty and institutions that participate in the meeting .
this translates into improved educational and experiential opportunities for the students of these faculty members .
an important goal of n.e.u.r.o.n . is to build the field of neuroscience from the bottom - up ; hence , a meeting devoted to having student participants as the focus is essential .
it is our aim to encourage neuroscientists in training and to continue to emphasize integration and cross - discipline approaches .
the conference strives to serve these goals and provide an important bridge between undergraduate and graduate training programs and experiences , which will facilitate and encourage the entree of junior neuroscientists on to graduate and professional schools .
improving training opportunities is integral to ensure that there are future scientists and health care providers with appropriate scientific skills .
cheryl frye ( suny - albany ) , priscilla kehoe ( trinity college ) , and cheryl mccormick ( bates college ) .
a dialogue was initiated at a neuroscience education training conference held at trinity college and supported by the pew charitable trust through the new england consortium of undergraduate science education ( necuse ) .
frye , kehoe , and mccormick identified that there was no one conference that fills the needs of neuroscientists - in - training , educators , and those from different institutional backgrounds .
they polled their colleagues to ascertain the level of interest in this endeavor and found others that were eager to be involved in an organization that had as its purpose the promotion of interaction between undergraduates , graduate students , and faculty at small colleges and universities throughout the region .
the northeast is an ideal geographical region for such a meeting , as most schools are within easy driving distance of one another . as such , n.e.u.r.o.n .
was conceived of as a meeting with single sessions , which utilizes a range of educational approaches in order to bring the participants closer to topical material in neuroscience and to provide important input for furthering participants development as neuroscientists ( blasberg et al .
, 2003a , b ) . in order to establish n.e.u.r.o.n . , a steering committee was formed .
initially , eight individuals , who assisted in the organization and recruitment of participants , comprised the steering committee .
although the steering committee continues to serve the same functions today , of encouraging participation and providing input about the conference , it has expanded to over 30 members and institutions .
frye , kehoe , and mccormick ) have worked closely with local organizers at host institutions ( trinity , wellesley , and wheaton colleges ) .
others , off - site , have handled the program , and other logistical aspects of the meeting , such as hosting keynote speakers and workshop leaders . by having a new institutional host every three years
, it enables n.e.u.r.o.n . to truly be an organization that is embraced by the region and no one institution . disseminating the work associated with
another important organizational tool that was central to the success of n.e.u.r.o.n . was the development of an effective web site .
the creation of this web site provided a central nexus for dissemination of information about n.e.u.r.o.n . as well , a counter that recorded the number of log - ins from new sites enabled us to collect data showing an interest in our group , which was important for our initial funding .
david tieman of the university at albany has been the web master for the n.e.u.r.o.n .
the web site is updated regularly to provide details about future meetings , progress of past meetings , and to serve as an important clearing house of contacts for steering committee members and educational programs in neuroscience .
an important factor that enabled n.e.u.r.o.n . to become established was initial funding provided by necuse and the first host institution , trinity college .
necuse , the organization that originally funded the conferences on neuroscience education from which the idea of n.e.u.r.o.n . grew , provided key financial support for the two initial meetings . as well , trinity college also generously contributed funds for the keynote speakers at the first conferences and hosted the meeting for the first three years .
wellesley and wheaton colleges were the hosts in subsequent three year increments and provided integral support , as well .
initially , the other institutions represented by the steering committee also bore some of the expenses of photocopying and mailing announcements , calls for papers , and programs . with this grass roots support that provided for the first two meetings
, we were able to collect preliminary data that demonstrated that the conference was engaging and effective , which was integral to garner further extramural support .
the third year of funding was obtained by a one - year nimh r13 grant .
meetings have been supported by a five - year nimh r13 grant that began in 1999 . this previous funding has allowed us to reach out to a number of trainees and faculty members involved in neuroscience research .
it is our hope that we will continue to have financial support for this important educational venue .
this has been accomplished by asking participants to complete a one - page survey that includes both closed- and open - ended questions about each feature of the meeting . in particular , respondents are asked to rate the effectiveness of the keynote speakers , the workshops , the poster session , as well as other aspects of the meeting , using a 15 point likert scale ( with 1 being the lowest and 5 being the highest rating ) .
n.e.u.r.o.n . has been a success in large part due to the interest and generosity of many leaders in the field of neuroscience .
each year , a prominent researcher is invited to give the keynote address on a current topic in neuroscience .
this address provides faculty and trainees alike with the opportunity to learn about cutting - edge research .
as table 1 indicates , the majority of the keynote speakers have been current or past presidents of the society for neuroscience or members of the national academy of science .
some might question the utility of having such high - powered speakers interact with students .
we have found that our speakers have been readily able to engage with students and that students have also benefited from having a related paper to read prior to the keynote talk .
notably , in addition to their talk , most of the keynote speakers have participated in the entire days activities .
keynote speakers have gone to great lengths to visit students posters , to meet with students over lunch , to attend the faculty workshops , and to talk with their colleagues ( frye et al . , 1999 ) .
n.e.u.r.o.n.s annual conference includes workshops for faculty and trainees , as well as a keynote address .
workshops led by expert consultants are offered to faculty and students to provide information about training and career development and opportunities .
participant suggestions have led to the development of separate workshops for undergraduates , graduate students , and faculty .
past workshops have included topics such as web - based teaching resources , and teaching responsible conduct for faculty members , and
career options in neuroscience and ethics in neuroscience for trainees ( table 2 ) . in each of these cases ,
specialists in the area of the desired workshop provided training ( frye et al . , 2000 ) .
each participant at n.e.u.r.o.n.s annual conference is invited to present a poster . over sixty posters
were presented at the may 2004 meeting ( fig . 1 , table 3 ) .
during the poster session , students interact with faculty from different institutions and gain valuable experience in presenting research data .
, student interactions during the poster session expose trainees to other areas of neuroscience research and allow for the opportunity to expand scientific interests .
one - on - one discussions between and among trainees and faculty also provide students with information about graduate school and allow students to form important connections with potential advisors .
participant response has indicated that the poster session is one of the most enjoyable and useful aspects of the annual meeting . as a result of feedback that participants were interested in making their research available to others outside of the poster session , abstracts can now be published in n.e.u.r.o.n.s associated journal ( journal of behavioral and neuroscience research ;
academic2.strose.edu/math_and_science/flintr/jbnr/ ) .
a strength of n.e.u.r.o.n . has been the number of women involved . as table 4
this representation is not surprising given the founders are women neuroscientists , who have active laboratories with many students that have looked to them as important role models . our present goals for n.e.u.r.o.n .
include trying to involve greater numbers of racial and ethnic minorities and other persons from disadvantaged groups at the meeting . at our most recent meeting , participation by self - identified racial and ethnic minorities had increased to a high of 17% , up from a meeting low of 11% at the prior years meeting ( table 4 ) .
another improvement at our recent meeting was trying to establish how many financially disadvantaged students participate in n.e.u.r.o.n . to address this we asked participants to complete questionnaires regarding financial aid information , so as to determine whether economically - disadvantaged students are benefiting from n.e.u.r.o.n .
given that n.e.u.r.o.n . is a regional conference that students can attend for free and with little travel costs , it may provide a particularly important service for students that do not have additional resources to travel to other conferences . for most students ,
this is their first or only conference experience and as such it can be a key factor in encouraging some students on to further professional training .
this year , we have begun to track the future plans of our participants .
although 90% will stay in neuroscience , of these 66% will be in the same position whereas 24% will be moving on to attend graduate school in neuroscience , attend medical school , or work as a technician in neuroscience .
n.e.u.r.o.n . has been a success in large part due to the interest and generosity of many leaders in the field of neuroscience .
each year , a prominent researcher is invited to give the keynote address on a current topic in neuroscience .
this address provides faculty and trainees alike with the opportunity to learn about cutting - edge research .
as table 1 indicates , the majority of the keynote speakers have been current or past presidents of the society for neuroscience or members of the national academy of science .
some might question the utility of having such high - powered speakers interact with students .
we have found that our speakers have been readily able to engage with students and that students have also benefited from having a related paper to read prior to the keynote talk .
notably , in addition to their talk , most of the keynote speakers have participated in the entire days activities .
keynote speakers have gone to great lengths to visit students posters , to meet with students over lunch , to attend the faculty workshops , and to talk with their colleagues ( frye et al . , 1999 ) .
n.e.u.r.o.n.s annual conference includes workshops for faculty and trainees , as well as a keynote address .
workshops led by expert consultants are offered to faculty and students to provide information about training and career development and opportunities .
participant suggestions have led to the development of separate workshops for undergraduates , graduate students , and faculty .
past workshops have included topics such as web - based teaching resources , and teaching responsible conduct for faculty members , and
career options in neuroscience and ethics in neuroscience for trainees ( table 2 ) . in each of these cases ,
specialists in the area of the desired workshop provided training ( frye et al . , 2000 ) .
each participant at n.e.u.r.o.n.s annual conference is invited to present a poster . over sixty posters
were presented at the may 2004 meeting ( fig . 1 , table 3 ) .
during the poster session , students interact with faculty from different institutions and gain valuable experience in presenting research data .
, student interactions during the poster session expose trainees to other areas of neuroscience research and allow for the opportunity to expand scientific interests .
one - on - one discussions between and among trainees and faculty also provide students with information about graduate school and allow students to form important connections with potential advisors .
participant response has indicated that the poster session is one of the most enjoyable and useful aspects of the annual meeting . as a result of feedback that participants were interested in making their research available to others outside of the poster session , abstracts can now be published in n.e.u.r.o.n.s associated journal ( journal of behavioral and neuroscience research ;
academic2.strose.edu/math_and_science/flintr/jbnr/ ) .
a strength of n.e.u.r.o.n . has been the number of women involved . as table 4
this representation is not surprising given the founders are women neuroscientists , who have active laboratories with many students that have looked to them as important role models . our present goals for n.e.u.r.o.n .
include trying to involve greater numbers of racial and ethnic minorities and other persons from disadvantaged groups at the meeting . at our most recent meeting , participation by self - identified racial and ethnic minorities had increased to a high of 17% , up from a meeting low of 11% at the prior years meeting ( table 4 ) .
another improvement at our recent meeting was trying to establish how many financially disadvantaged students participate in n.e.u.r.o.n . to address this we asked participants to complete questionnaires regarding financial aid information , so as to determine whether economically - disadvantaged students are benefiting from n.e.u.r.o.n .
is a regional conference that students can attend for free and with little travel costs , it may provide a particularly important service for students that do not have additional resources to travel to other conferences . for most students ,
this is their first or only conference experience and as such it can be a key factor in encouraging some students on to further professional training .
this year , we have begun to track the future plans of our participants .
although 90% will stay in neuroscience , of these 66% will be in the same position whereas 24% will be moving on to attend graduate school in neuroscience , attend medical school , or work as a technician in neuroscience .
n.e.u.r.o.n.s success has allowed it to serve as a model for similar groups in other regions of the country .
, the society of young neuroscientists and professors of the southeast ( http://csm.jmu.edu/biology/clelancl/synapse/ ) was developed using n.e.u.r.o.n . as a model ( blasberg et al .
, 2003a , b ; frye et al . , 1998 ; talley et al . , 2003 ; morgan et al . ,
that it can be used further as an example by other groups to encourage neuroscience training and education .
we hope to accomplish this goal by hosting a meeting such as project kaleidoscope ( pkal ) concurrent with n.e.u.r.o.n . at wheaton college , which would highlight the aspects of the meeting that make it a superb model for other groups that want to enhance neuroscience education and research . in hopes of creating greater community integration , n.e.u.r.o.n .
as an educational activity , will help increase involvement of the scientific community , and provide a possible source of funding for future meetings . in order to further increase representation by all types of minorities at future n.e.u.r.o.n .
meetings the venue of the meeting will change in 2006 to a more urban setting .
racial and ethnic minority students make up 23 and 17.4% , respectively , of the student body at these institutions and many students are economically disadvantaged . other approaches to make n.e.u.r.o.n
. as inclusive as possible will be to provide more financial support for students and other role models .
we hope to provide travel awards , with priority given to students from under - represented groups .
a concerted effort will also be made to increase the number of minority mentors / speakers at n.e.u.r.o.n .
in addition to his talk entitled , birdsong and the neurobiology of human language , dr .
we believe that these measures will increase the participation of under - represented groups at n.e.u.r.o.n . in order to make n.e.u.r.o.n . as inclusive as possible
, we have also expanded the n.e.u.r.o.n . steering committee to include faculty from larger institutions , many of which have world - renowned neuroscience training programs .
, our lab has held very successful events for brain awareness week , including a brain bee and lab tours for high school students .
we have also recently begun to involve high school science teachers in research through nsf - funded research experience for teachers programs .
these projects enhance science in high schools and expose students to neuroscience research at a critical period when they are figuring out career path(s ) they may be interested in . these and other methods of community outreach will be the topics of workshops at n.e.u.r.o.n . and pkal .
we hope this will further our goal of enhancing neuroscience education , research , and outreach , which enhances science literacy in the community . because this group is committed to the integration of traditional and non - traditional approaches in neuroscience , it is essential to have a regularly held forum where interactions among scientists with a variety of training backgrounds and perspectives can be developed and fostered .
give students and faculty a formal voice and a mechanism for meeting and exchanging ideas on a regular basis .
it is our hope that by continuing to offer these opportunities at n.e.u.r.o.n . and further promoting greater networking and contacts between the participating individuals and institutions , that such contact will be sought and maintained between annual conferences . | ### Summary:
: the northeast under / graduate organization for neuroscience ( n.e.u.r.o.n . ) was established in 1996 to provide a forum for undergraduate and graduate students and faculty in neuroscience to interact with each other .
n.e.u.r.o.n .
organizes a yearly one - day conference in the northeast . while scientific meetings exist that serve the purpose of enhancing undergraduate research or neuroscience research , n.e.u.r.o.n .
is unique in that it is a small , local conference , aimed specifically at undergraduates looking to pursue careers in neuroscience . during the conference
, participants attend workshops , poster sessions , and a keynote address that provide them with information about current topics in neuroscience .
trainees gain valuable experience presenting scientific research in poster sessions and make connections with colleagues . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: electrocyclic reactions are becoming increasingly
valuable in synthesis
as chemists continue to develop new methods for catalyzing these cyclizations . in recent years
, mild catalytic methods for achieving
neutral , cationic , and anionic cyclizations have been reported
with a broad set of applications , including efficient synthesis of
heterocycles and rapid , stereospecific assembly of densely functionalized
carbocyclic systems .
as one might expect , neutral cyclizations occur
either spontaneously or with heating , cationic reactions typically
require catalysis with either a brnsted or lewis acid species ,
and anionic reactions proceed under basic conditions .
however , emerging
evidence suggests that cationic electrocyclizations
can occur thermally without the addition of acid . in this paper
, we examine cationic 4 and neutral
6 electrocyclic reactions of dienyl diketones , determine the
utility of the reactions for the selective synthesis of either cyclopentenones
or 2h - pyrans , and discuss the apparent contradiction
of proposing a cationic electrocyclization mechanism for a reaction
that occurs under neutral or even basic conditions .
we previously
described a lewis acid that promoted 1,6-conjugate
addition to initiate nazarov cyclization .
for example , treatment of dienyl diketones 1 ( r h ) with catalytic lewis acid , lithium chloride ,
and triethylamine as a base , and in the presence of a nucleophile ,
results in their smooth conversion to cyclopentenones 2 ( eq 1 ) .
however , treatment of the same dienyl
diketones 1 with the nucleophilic tertiary amine dabco
( 1,4-diazabicyclo[2.2.2]octane ) leads to two different types of cyclization
products : either 2h - pyrans 3 ( eq 2 ) or 4-methylene cyclopentenones 4 ( eq 3 ) , depending upon the r substituent on the dienone . in this paper
, we analyze the
factors that control cyclization behavior and allow for the efficient
synthesis of elusive pyrans 3 , 5-hydroxy -alkylidene
cyclopentenones 4 , or the highly substituted cyclopentenone
systems of type 2 .
treatment
of 1a ( r = me ) with dabco ( 10
mol % ) at room temperature gave a 1:2 ratio of 1a and 3a after 8 h ( entry 1 , table 1 ) .
similarly ,
when pyran 3a is resubjected to 1 equiv of dabco for
24 h , 1a and 3a are again obtained at a
1:2 ratio .
in contrast , formation of pyrans 3 from dienyl
diketones 1 is efficient in substrates with bulkier r substituents ( entries 24 , table 1 ) . as shown in table 1 , rapid , complete
conversion to 3
is observed for substrates with larger
r substituents ( e.g. , 1b , 1c , 1d ) .
interestingly , when 1e is subjected
to the reaction conditions ( entry 5 ) , pyran 3e was generated ,
but the cyclization was much slower than that of the previous substrates ( 1b or 1d ) . presumably , this is because the steric
impact of a methylene group at the homoallylic position is not as
strong as that of an acetate .
these findings are consistent with previous
studies that found that an oxatriene / pyran ratio is affected by substitution
pattern and that steric bulk at r favors pyran 3 .
the diene was dissolved
in thf ( 1
m ) , and dabco ( 10 mol % ) was added .
the solution was stirred at room
temperature until all starting material was consumed by tlc , unless
otherwise noted .
conversion
to 3a is incomplete ( see eq 2 ) ;
equilibrium is
reached after 2 h. in the case of secondary allylic acetate 1c , treatment
with dabco rapidly produces 5c ( entry 3 , table 1 ; eq 4 ) . monitoring the reaction
by h nmr at low concentration
, we were able to observe
the following reaction sequence : cyclization generates pyran 3c , followed by net loss of hoac to afford trans - alkene 5c .
we suggest that the acetate is first ionized
to generate a stabilized cation and then deprotonated at the homoallylic
position.4 to further probe this reactivity and the role
of the nucleophile ,
we subjected several dienyl diketones to both pyrrolidine and dabco
( table 2 ) .
when diketones 1a and 1f were treated with pyrrolidine , they proceeded rapidly to
cyclopentenones 2a and 2f , even without
a lewis acid .
however , when treated with dabco , they proceeded to 3a and 4f , respectively , as described above .
dienyl diketones 1 g and 1h showed the same
cyclization behavior : when treated with pyrrolidine , both substrates
proceeded to cyclopentenone products 2 g and 2h , respectively , as a mix of diastereomers ( entries 3 and 5 , table 2 ) .
when treated with dabco , 1 g and 1h produced pyrans 3 g and 3h , respectively
( entries 4 and 6 , table 2 ) .
this demonstrates
that the outcome of the reaction can be controlled by nucleophile
choice .
x - ray crystallography confirms that product 2a has the same stereochemistry ( supporting information ) as previously described cyclopentenones produced when a lewis acid
was used to catalyze the reaction .
reaction conditions : nucleophile
( 1 equiv ) was added to substrate in thf ( 1 m ) , and the reaction was
monitored by tlc or nmr .
product
obtained as an inseparable
mixture of diastereoisomers : 1.2:1 dr ( 2 g ) and 6:1 dr
( 2h ) as determined by h nmr spectroscopy .
previous reports have established
that the interconversion between
the cis-1,3-dienone and 2h - pyran
by oxa-6 electrocyclization / retro - electrocyclization is facile ; however , the studies suggest that equilibrium
favors the closed form only when the pyran contains sterically demanding
substitutents , or is part of a bicyclic
system , and is therefore substrate dependent .
however , trans-1,3-dienone is unreactive unless it
can be smoothly isomerized to the cis isomer .
the
isomerization is traditionally accomplished by uv irradiation ; however , these reactions often have low yields
and generate undesired side products . preparing cis-1,3-dienones directly is also challenging ;
thus , the dabco protocol demonstrated in table 1 represents an improved method for the synthesis
of 2h - pyrans , which are found in a number of natural
products .
a mechanistic hypothesis
for the observed cyclization behavior
of dienyl diketones 1 is offered in scheme 1 . upon 1,6-conjugate addition
of an amine nucleophile to 1 ,
the internal olefin is
able to rotate freely in intermediate 6 , enabling the
substrate to adopt a conformation in which it can undergo cyclization .
when the nucleophile is a secondary amine , 4 electrocyclization
( 6 to 7 ) is followed by proton transfer
to form cyclopentenone adduct 2 .
using the tertiary amine dabco as the nucleophile , the
outcome
and rate of reaction are dependent upon the size of r.
if r = h , 1,6-addition / nazarov
cyclization produces 7 as usual , and then elimination of dabco produces methylene
cyclopentenone 4 .
however , if r
h , the high - energy electrocyclization product 7 can not
be deprotonated or otherwise neutralized , so the only available pathway
is retro-4 electrocyclization , which regenerates s - cis6 .
the elimination of dabco from 6 can produce either 1e ( from the s - trans isomer ) or 1z ( from the s - cis isomer ) .
since 1z is never observed by nmr , we
surmise that it undergoes rapid 6 electrocyclization to afford
pyran 3 . with respect to the 6 electrocyclization
pathway ,
we propose
that the ratio of s - trans6 to s - cis6 increases as r and r become larger , corresponding to a higher proportion of 1z/3 relative to 1e ( see eq 2 ) .
furthermore ,
larger substituents at r increase the overall rate of
pyran formation ( see table 1 ) , suggesting that
bond rotation is rate - limiting .
these observations lead to the general
prediction that in reactions of dienyl diketones 1 with
uncharged nucleophiles , 4 cyclization products 2 and 4 will be obtained if intermediate 7 can be deprotonated ( i.e. , when the nucleophile is a secondary amine
or when r= h ) , whereas 6 cyclization products 3 ( or an equilibrium mixture of 1e and 3 ) will result when it can not . to test the feasibility of the proposed
retro-4 electrocyclization , we
treated pyrrolidine adduct 2h ( scheme 2 ) with iodomethane to give intermediate 7h .
this
intermediate is analogous to the zwitterions formed
when dabco is used , and dienyl diketone 1h is produced .
presumably , a retro - nazarov - type reaction of 7h produces 6h , which can then eliminate to give the dienyl diketone 1h .
electrocyclizations occur
in the presence of neutral nucleophiles alone via a putative zwitterionic
intermediate , we treated methyl - substituted dienyl diketone 1a with anionic nucleophiles to test the limits of nucleophile - initiated
cyclizations .
reactions with sodium methoxide ( eq 5 ) and sodium ethanethiolate
( eq 6 ) proceeded very cleanly to afford addition products 8 and 9 , respectively ( scheme 3 ) .
sodium cyanide and sodium azide gave complex mixtures of products ,
presumably resulting from unselective 1,2- , 1,4- , and 1,6-addition .
electrocyclization
might occur without acid , and without the formation of a discrete
pentadienyl cation , leads to the following questions : is this really
nazarov cyclization , and does it conform to pericyclic selection rules ?
we propose that even though critical intermediate 6 is
not cationic ( scheme 1 ) , it can be considered
to have pentadienyl cation character in the same way
cyclopropenone has aromatic character and cyclopentadienone has antiaromatic
character .
a survey of the literature reveals that cyclization of
enolates of type 10 and 11 ( scheme 4 ) generates cyclopentenones with suspiciously high
diastereoselectivity under basic conditions . because a canonical pentadienyl cation intermediate can not be invoked
in these reactions , one could argue that these cyclizations are intramolecular
aldol reactions that occur without conservation of orbital symmetry .
however , the diastereoselectivity observed is
difficult to rationalize unless one invokes conrotatory electrocyclization .
furthermore , the systems have the same substitution pattern as piancatelli
cyclization , which is also an intramolecular
aldol reaction ( scheme 4 ) , but one that is
acid catalyzed and therefore more easily rationalized as pericyclic . in our system , the 1,6-conjugate - addition - initiated cyclization
of dienyl diketones 1 generates cyclopentenones with
the same relative stereochemistry ( cf .
2a2i , 8 , and 9 ) independent of whether
the reaction is catalyzed by a lewis acid ( eq 1 ) , uncatalyzed under neutral conditions ( table 2 , entries 1 , 3 , 5 , and 7 ) , or uncatalyzed under basic conditions
( eqs 5 and 6 ) .
this suggests that 4 conrotatory cyclization
occurs in all of the cyclizations of dienyl diketone 1 through either an enol or an enolate intermediate of type 11a ( scheme 4 ) with pentadienyl cation
character .
it is also important to note that while conformer 11b would undergo 4 conrotatory cyclization to produce
the opposite ( undetected ) diastereoisomer , it is likely that the orientation
of the carbonyl could make 6 electrocyclization more favorable
for this conformer . in conclusion
, we have described the 1,6-conjugate
addition of
a nucleophile to dienyl diketones to generate cyclopentenones 2 and 4 and 2h - pyrans 3 through a bifurcated mechanism .
we have also demonstrated
that electrocyclization / retroelectrocyclization pathways control product
distribution in these reactions , which suggests that the intermediates
undergoing 4 cationic nazarov electrocyclization need not carry
a net positive charge .
further investigations are underway , including
asymmetric variants of the 1,6-conjugate - addition / nazarov - cyclization
sequence .
substrates 1a and 1d f are known
compounds synthesized following reported procedures .
dienyl diketone was prepared following a known procedure from tert - butyldimethyl((3-methylene-5-phenylpent-4-yn-2-yl)oxy)silane
and phenylglyoxal .
rh(cod)2otf ( 0.131 g , 0.28 mmol ) and
rac - binap ( 0.208 g , 0.34 mmol ) were added to a flame - dried 100 ml
round - bottom flask in a glovebox .
dry dichloroethane ( dce ) ( 25 ml )
was then added , and the reaction mixture was allowed to stir for 30
min at room temperature in an inert atmosphere ; the color changed
from red to orange .
phenylglyoxal ( 1.28 g , 8.4 mmol ) and ene - yne ( 5.6
mmol ) were then added to the dce ( 25 ml ) , and the solution was purged
with hydrogen gas for 1 h. during this time , it became necessary to
flush a clogged needle with dce .
once all of the solids had dissolved ,
the outlet was removed and the flask was charged with hydrogen gas
overnight , during which time the color changed from dark red to black .
once the starting material was consumed , the reaction products were
concentrated and subjected to quick column chromatography ( silica
gel , 4:1 hexane / etoac ) to give a yellow product that was impure by
tlc .
this was then taken up in dmso , ( 3 ml ) and one portion of ibx
( 1.18 g , 4.2 mmol ) was added .
the reaction mixture was allowed to
stir until all of the starting material was consumed by tlc .
the reaction
products were then quenched with water , extracted with diethyl ether ,
dried with mgso4 , and concentrated .
the products were then
purified by flash chromatography ( silica gel , 9:1 hexane / etoac ) .
the product was synthesized according to
general procedure a , isolated as a yellow oil , and purified by flash
chromatography ( 9:1 hexane / etoac , 1.35 g , 87% ) .
h nmr
( 400 mhz , cdcl3 ) : 7.99 ( d , j =
7.5 hz , 2h ) , 7.71 ( t , j = 7.4 hz , 1h ) , 7.57 ( t , j = 7.6 hz , 2h ) , 7.477.41 ( m , j = 3.2 hz , 3h ) , 7.31 ( dd , j = 6.5 , 3.7 hz , 2h ) ,
5.39 ( s , 2h ) , 1.48 ( s , 3h ) .
c nmr ( 101 mhz , cdcl3 ) : 196.9 , 195.5 , 149.2 , 141.3 , 137.5 , 134.8 , 134.0 ,
133.4 , 130.3 , 129.8 , 129.1 , 128.6 , 128.5 , 128.2 , 21.3 .
ir ( neat , cm ) : 3460 , 2955 , 2363 , 2335 , 1716 , 1456 , 1439 , 1288 ,
1218 , 1153 , 1067 , 696 . lrms ( apci , m / z ) : calcd for c19h16o2 , 276.1 ; found ,
276.7 .
the product was synthesized according
to general procedure a and purified by silica gel chromatography using
9:1 hexane / etoac as the eluent to give the dienyl diketone 1b ( 0.67 g , 72% yield ) .
h nmr ( 400 mhz , cdcl3 ) :
7.90 ( d , j = 7.9 hz , 2h ) , 7.64 ( t , j = 7.3 hz , 1h ) , 7.49 ( dd , j = 17.6 , 10.0 hz , 2h ) ,
7.38 ( d , j = 4.8 hz , 3h ) , 7.277.19 ( m , 2h ) ,
7.16 ( s , 1h ) , 5.54 ( s , 1h ) , 5.44 ( s , 1h ) , 4.20 ( s , 2h ) , 1.95 ( s , 3h ) .
c nmr ( 126 mhz , cdcl3 ) : 196.1 , 195.0 , 170.0 , 148.0 ,
144.7 , 139.4 , 138.4 , 134.9 , 133.6 , 133.2 , 129.8 , 129.7 , 129.3 , 129.1 ,
128.9 , 128.5 , 128.4 , 127.5 , 126.3 , 64.4 , 20.8 .
ir ( neat , cm ) : 3059 , 2160 , 2033 , 1975 , 1739 , 1670 , 1597 , 1450 , 1373 , 1226 , 1041 ,
698 . lrms ( apci , m / z ) : calcd for
c21h18o4 , 334.4 ; found , 334.8 . the product was synthesized according
to general procedure a. chromatography ( silica gel , 9:1 hexane / etoac )
afforded 1c as a bright yellow oil ( 0.316 g , 15% over
two steps ) .
h nmr ( 500 mhz , cdcl3 ) :
7.97 ( dd , j = 8.3 , 1.2 hz , 2h ) , 7.70 ( dd , j = 10.6 , 4.3 hz , 1h ) , 7.57 ( t , j = 7.8
hz , 2h ) , 7.487.38 ( m , 3h ) , 7.337.27 ( m , 3h ) , 7.16
( s , 1h ) , 5.41 ( s , 1h ) , 5.185.10 ( m , 2h ) , 2.03 ( s , 3h ) , 1.54
( m , j = 18.8 , 14.0 , 9.3 , 5.3 hz , 3h ) , 1.341.23
( m , 2h ) , 1.151.00 ( m , 2h ) , 0.87 ( t , j = 7.4
hz , 3h ) .
c nmr ( 126 mhz , cdcl3 ) : 196.0 ,
195.1 , 170.0 , 143.5 , 142.7 , 139.3 , 134.7 , 133.4 , 133.2 , 129.6 , 129.6 ,
129.0 , 128.7 , 128.5 , 123.5 , 74.9 , 36.1 , 21.0 , 18.6 , 13.6 .
hrms ( esi - tof , m / z ) : [ m + h ] calcd for c24h24o4 , 377.1753 ; found , 377.1751 . the product was synthesized according
to general procedure a , isolated as a yellow oil , and purified by
flash chromatography ( 9:1 hexane / etoac , 1.64 g , 84% ) .
h nmr ( 400 mhz , cdcl3 ) : 7.91 ( d , j = 7.6 hz , 2h ) , 7.64 ( t , j = 7.3 hz , 1h ) , 7.51 ( t , j = 7.6 hz , 2h ) , 7.37 ( d , j = 6.3 hz , 3h ) ,
7.24 ( d , j = 7.7 hz , 2h ) , 7.14 ( s , 1h ) , 5.33 ( s ,
1h ) , 5.28 ( s , 1h ) , 3.90 ( t , j = 6.5 hz , 2h ) , 2.15
( t , j = 6.5 hz , 2h ) , 1.94 ( s , 3h ) .
c
nmr ( 101 mhz , cdcl3 ) : 196.4 , 195.2 , 170.9 , 147.7 ,
140.8 , 138.0 , 134.9 , 133.3 , 130.3 , 130.0 , 129.1 , 128.4 , 127.3 , 62.7 ,
33.5 , 20.9 .
ir ( neat , cm ) : 3441 , 3059 , 2931 , 1747 ,
1681 , 1597 , 1492 , 1450 , 1265 , 1172 , 1103 , 732 , 694 . lrms ( apci , m / z ) : calcd for c22h20o4 , 348.1 ; found , 348.8 .
the product was synthesized according
to general procedure a , isolated as a yellow oil , and purified by
flash chromatography ( 9:1 hexane / etoac , 1.79 g , 85% ) .
h nmr ( 400 mhz , cdcl3 ) : 7.91 ( d , j = 7.2 hz , 2h ) , 7.64 ( t , j = 7.4 hz , 1h ) , 7.51 ( t , j = 7.7 hz , 2h ) , 7.407.34 ( m , 3h ) , 7.267.20
( t , 2h ) , 7.13 ( s , 1h ) , 5.28 ( d , j = 1.0 hz , 1h ) ,
5.22 ( s , 1h ) , 3.87 ( t , j = 6.2 hz , 2h ) , 2.01 ( s ,
3h ) , 1.82 ( t , j = 7.1 hz , 2h ) , 1.331.20 ( m ,
4h ) .
c nmr ( 101 mhz , cdcl3 ) : 196.6 ,
195.4 , 171.2 , 148.4 , 144.5 , 137.8 , 134.8 , 133.9 , 133.4 , 130.0 , 129.8 ,
129.1 , 128.6 , 128.4 , 125.9 , 64.2 , 34.1 , 28.1 , 25.1 , 21.1 .
ir ( neat ,
cm ) : 2947 , 2866 , 1735 , 1670 , 1581 , 1450 , 1365 ,
1238 , 1203 , 1141 , 979 , 663 .
lrms ( apci , m / z ) : calcd for c24h24o4 ,
376.2 ; found , 376.8 .
the product was synthesized according to
general
procedure a , obtained as a yellow oil , and carried through to the
next reaction without further purification .
h nmr ( 400
mhz , cdcl3 ) : 7.95 ( d , j = 7.2
hz , 2h ) , 7.65 ( t , j = 10.6 hz , 1h ) , 7.52 ( t , j = 7.7 hz , 2h ) , 7.367.46 ( m , 3h ) , 7.267.31
( m , 2h ) , 7.16 ( d , j = 11.0 hz , 1h ) , 6.486.61
( m , 1h ) , 5.71 ( d , j = 16.9 hz , 1h ) , 5.56 ( d , j = 10.1 hz , 1h ) .
c nmr ( 101 mhz , cdcl3 ) : 196.1 , 195.1 , 147.0 , 138.5 , 134.9 , 133.3 , 133.2 ,
132.8 , 130.3 , 129.9 , 129.2 , 129.1 , 128.6 , 128.5 .
ir ( neat , cm ) : 3059 , 1735 , 1677 , 1658 , 1612 , 1450 , 1222 , 1141 ,
698 . hrms ( esi - tof , m / z ) : [ m + h ] calcd for c18h15o2 , 263.1072 ;
found , 263.1072 .
dienyl diketone 1 g was prepared
by dissolving 1h in meoh ( 1 ml ) and adding hcl ( 1 m ,
aq ) dropwise while stirring .
if formation of a precipitate was observed ,
methanol was added until it dissolved .
product was extracted with
diethyl ether and concentrated to afford 1 g as a bright
yellow oil ( 0.46 g , 94% yield ) .
h nmr ( 500 mhz , cdcl3 ) : 7.98 ( d , j = 7.4 hz , 2h ) , 7.70
( t , j = 7.4 hz , 1h ) , 7.57 ( t , j =
7.8 hz , 2h ) , 7.487.37 ( m , 4h ) , 7.30 ( dd , j = 6.0 , 4.6 hz , 3h ) , 7.24 ( s , 1h ) , 5.48 ( s , 1h ) , 5.07 ( s , 1h ) , 4.25
( m , j = 6.4 hz , 1h ) , 1.64 ( d , j =
18.2 hz , 1h ) , 1.26 ( d , j = 6.4 hz , 3h ) .
c nmr ( 126 mhz , cdcl3 ) : 196.0 , 195.1 , 147.2 , 144.7 ,
139.4 , 134.8 , 133.8 , 133.2 , 129.62 , 129.55 , 129.0 , 128.7 , 128.4 , 121.1 ,
69.4 , 22.8 . hrms ( esi - tof , m / z ) :
[ m + h ] calcd for c20h18o3 , 307.1334 ; found , 307.1336 .
the product was synthesized according to
general procedure a. chromatography ( silica gel , 9:1 hexane / etoac )
afforded 1h as a bright yellow oil ( 0.71 g , 30% yield
over two steps ) .
h nmr ( 500 mhz , cdcl3 ) :
7.99 ( d , j = 7.6 hz , 2h ) , 7.69 ( d , j = 7.3 hz , 1h ) , 7.56 ( t , j = 7.7 hz , 2h ) , 7.497.38
( m , 3h ) , 7.31 ( d , j = 6.7 hz , 2h ) , 7.26 ( s , 1h ) ,
5.45 ( s , 1h ) , 5.02 ( s , 1h ) , 4.20 ( q , j = 6.2 hz ,
1h ) , 1.17 ( d , j = 6.3 hz , 3h ) , 0.85 ( d , j = 12.0 hz , 9h ) , 0.03 ( d , j = 11.4 hz , 6h ) .
c nmr ( 126 mhz , cdcl3 ) : 196.32 , 195.36 ,
147.66 , 145.39 , 138.93 , 134.66 , 134.02 , 133.28 , 129.7 , 129.6 , 129.0 ,
128.6 , 128.3 , 120.9 , 70.1 , 25.7 , 24.4 , 18.0 , 5.0 .
hrms ( esi - tof , m / z ) : [ m + h ] calcd for c26h32o3si , 421.2199 ; found , 421.2196 . to a solution
of dienyl diketone in thf ( 1 m ) was added dabco in one portion at
room temperature .
the reactions were monitored by tlc until the starting
material was consumed ( in cases where the starting material and product
have identical rf values , the reactions
were monitored by h nmr ) .
the reaction was then quenched
with hcl ( 1 m , aq ) , and the mixture was extracted with diethyl ether ,
dried with magnesium sulfate , and concentrated .
the product was obtained from 1a using general procedure b , isolated as a bright yellow oil , and
purified by flash chromatography ( 9:1 hexane / etoac , 33 mg , 66% ( equilibrium
mix of 2h - pyran and dienyl diketone ) ) .
h nmr ( 500 mhz , cdcl3 ) : 7.79 ( d , j = 7.4 hz , 2h ) , 7.42 ( t , j = 7.4 hz , 1h ) , 7.29 ( dd , j = 16.8 , 9.2 hz , 2h ) , 7.217.06 ( m , 5h ) , 6.00 ( d , j = 0.9 hz , 1h ) , 4.69 ( s , 2h ) , 1.88 ( s , 3h ) .
c nmr ( 126 mhz , cdcl3 ) : 191.5 , 144.7 , 1370 , 136.8 ,
132.7 , 130.4 , 129.6 , 128.4 , 128.2 , 128.1 , 127.3 , 123.3 , 121.7 , 68.9 ,
19.2 . hrms ( esi - tof , m / z ) : [ m +
h ] calcd for c19h16o2 , 277.1229 ; found , 277.1225 .
the product was obtained from 1b using general procedure b , isolated as a white solid , and purified
by flash chromatography ( 4:1 hexane / etoac , 49 mg , 98% ) h nmr ( 500 mhz , cdcl3 ) : 7.887.84 ( m , 2h ) ,
7.597.55 ( m , 1h ) , 7.537.47 ( m , 2h ) , 7.417.35
( m , 3h ) , 7.267.17 ( m , 2h ) , 6.35 ( 2 , 1h ) , 4.84 ( s , 1h ) , 4.76
( s , 1h ) , 2.17 ( s , 3h ) .
c nmr ( 126 mhz , cdcl3 ) : 191.3 , 170.8 , 147.2 , 136.4 , 136.2 , 133.3 , 129.9 , 129.8 ,
129.1 , 128.6 , 128.5 , 128.4 , 128.4 , 127.7 , 126.4 , 125.1 , 121.6 , 66.3 ,
64.5 , 21.0 .
2928 , 1739 , 1670 ,
1450 , 1234 , 1180 , 1022 . lrms ( apci , m / z ) : calcd for c21h18o4 , 234.4 ; found ,
234.8 . the product was obtained from 1d using general procedure b as a yellow oil after flash chromatograpy
( 9:1 hexane / etoac , 48 mg , 96% ) .
h nmr ( 400 mhz , cdcl3 ) : 7.63 ( t , j = 7.7 hz , 2h ) , 7.43
( t , j = 7.4 hz , 1h ) , 7.31 ( t , j =
7.7 hz , 2h ) , 7.217.10 ( m , 5h ) , 6.10 ( s , 1h ) , 4.73 ( s , 2h ) ,
4.26 ( t , j = 6.6 hz , 2h ) , 2.52 ( t , j = 6.4 hz , 2h ) , 2.08 ( s , 3h ) .
c nmr ( 101 mhz , cdcl3 ) : 191.5 , 171.0 , 145.8 , 136.7 , 136.6 , 133.1 , 129.9 ,
129.7 , 128.5 , 128.3 , 128.3 , 127.6 , 123.2 , 122.9 , 68.1 , 62.3 , 32.9 ,
21.1 .
ir ( neat , cm ) : 3425 , 3063 , 2962 , 2935 , 1735 ,
1678 , 1581 , 1492 , 1450 , 1365 , 1234 , 1037 , 698 . lrms ( apci , m / z ) : calcd for c22h20o4 , 348.1 ; found , 348.8 .
the product was obtained from 1e using general procedure b , isolated as a yellow oil , and purified
by flash chromatography ( 9:1 hexane / etoac , 44 mg , 84% ) .
h nmr ( 500 mhz , cdcl3 ) : 7.78 ( d , j = 7.1 hz , 2h ) , 7.41 ( t , j = 8.2 hz , 1h ) , 7.30 ( t , j = 7.7 hz , 2h ) , 7.197.10 ( m , 5h ) , 6.01 ( s , 1h ) ,
4.69 ( s , 2h ) , 4.10 ( t , j = 6.4 hz , 2h ) , 2.22 ( t j = 7.1 hz , 2h ) , 2.05 ( s , 3h ) , 1.741.56 ( m , 6h ) .
c nmr ( 126 mhz , cdcl3 ) : 191.6 , 171.3 ,
145.3 , 137.0 , 136.8 , 136.0 , 133.8 , 132.9 , 130.3 , 129.7 , 129.2 , 128.5 ,
128.3 , 128.2 , 127.5 , 123.8 , 123.5 , 121.3 , 68.1 , 64.2 , 58.9 , 42.3 ,
33.1 , 28.4 , 23.4 , 21.1 .
ir ( neat , cm ) : 2935 , 2858 ,
2360 , 2341 , 1735 , 1666 , 1597 , 1446 , 1365 , 1242 , 1018 , 698 . lrms ( apci , m / z ) : calcd for c24h24o4 , 376.2 ; found , 376.8 . the product was obtained from 1 g using general procedure b , isolated as a bright yellow oil , and
purified by flash chromatography ( 9:1 hexane / etoac , 43 mg , 86% ) .
h nmr ( 500 mhz , cdcl3 ) : 7.92 ( d , j = 7.6 hz , 2h ) , 7.43 ( t , j = 7.3 hz , 2h ) ,
7.347.17 ( m , 5h ) , 7.156.95 ( m , 3h ) , 6.65 ( s , 1h ) ,
5.43 ( s , 1h ) , 5.24 ( s , 2h ) , 5.09 ( d , j = 6.3 hz ,
1h ) , 1.54 ( d , j = 6.4 hz , 3h ) .
c nmr
( 126 mhz , cdcl3 ) : 195.3 , 143.2 , 138.2 , 136.5 , 133.6 ,
132.7 , 130.2 , 128.3 , 128.0 , 128.0 , 127.8 , 126.8 , 113.3 , 95.0 , 66.6 ,
18.0 . hrms
( esi - tof , m / z ) : [ m +
h ] calcd for c20h18o3 , 307.1334 ; found , 307.1336 .
the product was obtained from 1h using general procedure
b , isolated as a yellow oil , and purified by flash chromatography
( 9:1 hexane / etoac , 27 mg , 54% ) .
h nmr ( 500 mhz , cdcl3 ) : 7.837.78 ( m , 2h ) , 7.43 ( t , j = 7.4 hz , 1h ) , 7.32 ( t , j = 7.7 hz , 2h ) , 7.26 ( s ,
1h ) , 7.197.12 ( m , 5h ) , 6.14 ( d , j = 1.0 hz ,
1h ) , 4.78 ( d , j = 7.3 hz , 2h ) , 4.47 ( d , j = 6.3 hz , 1h ) , 1.35 ( d , j = 6.4 hz , 3h ) , 0.92 ( s ,
10h ) , 0.11 ( s , 7h ) .
c nmr ( 126 mhz , cdcl3 ) :
191.4 , 146.1 , 136.81 , 136.77 , 136.6 , 132.9 , 129.6 , 128.4 ,
128.2 , 128.1 , 127.4 , 123.0 , 119.7 , 69.3 , 65.4 , 25.8 , 25.8 , 22.9 , 18.2 ,
4.7 , 4.8 .
hrms ( esi - tof , m / z ) : [ m + h ] calcd for c26h32o3si , 421.2199 ; found , 421.2184 . the product
was obtained from 1c using general procedure b , isolated
as yellow oil , and purified by flash chromatography ( 9:1 hexane / etoac ,
35 mg , 84% ) .
h nmr ( 500 mhz , cdcl3 ) :
7.80 ( d , j = 7.5 hz , 2h ) , 7.43 ( t , j = 7.4 hz , 1h ) , 7.30 ( m , j = 20.1 , 12.4 hz , 3h ) ,
7.237.05 ( m , 6h ) , 6.17 ( d , j = 16.0 hz , 1h ) ,
6.11 ( s , 1h ) , 5.76 ( dt , j = 15.8 , 6.6 hz , 1h ) , 4.97
( s , 2h ) , 2.22 ( m , j = 7.0 hz , 2h ) , 1.07 ( t , j = 7.4 hz , 3h ) .
c nmr ( 126 mhz , cdcl3 ) : 191.2 , 146.1 , 136.9 , 136.7 , 134.5 , 132.8 , 129.8 , 129.6 ,
128.5 , 128.2 , 128.1 , 127.4 , 126.9 , 123.8 , 123.2 , 65.5 , 26.3 , 13.5 .
hrms ( esi - tof , m / z ) : calcd for c22h20o2 , 317.1542 ; found , 317.1544 . the product was obtained from 1f using general
procedure b and isolated as a pale yellow solid after
flash chromatography ( 9:1 hexane / etoac , 44 mg , 88%).h nmr ( 500 mhz , cdcl3 ) : 8.15 ( s , 1h ) , 7.88 ( d , j = 7.4 hz , 2h ) , 7.527.37 ( m , 6h ) , 7.31 ( dt , j = 19.4 , 6.9 hz , 3h ) , 5.61 ( s , 1h ) , 5.49 ( s , 1h ) , 3.39
( s , 1h ) .
c nmr ( 126 mhz , cdcl3 ) : 204.3 ,
152.6 , 149.9 , 140.1 , 139.9 , 130.5 , 129.6 , 128.8 , 128.6 , 128.1 , 127.4 ,
125.2 , 114.3 , 79.6 . hrms ( esi - tof , m / z ) : [ m + na ] calcd for c18h14o2na , 285.0891 ; found , 285.0899 .
to a solution
of dienyl diketone in thf ( 1 m ) was added pyrrolidine in one portion
at room temperature .
the reaction was then quenched with
hcl ( 1 m , aq ) , and the mixture was extracted with diethyl ether , dried
with magnesium sulfate , and concentrated .
the product was obtained from 1a using general procedure c and isolated as a red solid by aqueous
workup ( 280 mg , 85% ) .
h nmr ( 500 mhz , cdcl3 ) : 8.00 ( s , 1h ) , 7.87 ( d , j = 7.1 hz , 2h ) ,
7.537.43 ( m , 5h ) , 7.377.28 ( m , 3h ) , 2.492.22
( m , 6h ) , 1.68 ( s , 4h ) , 1.45 ( s , 3h ) .
c nmr ( 101 mhz ,
cdcl3 ) : 207.0 , 169.6 , 169.2 , 158.7 , 142.0 , 139.4 ,
130.4 , 129.3 , 128.8 , 128.6 , 128.2 , 127.0 , 125.5 , 84.1 , 52.9 , 52.7 ,
49.8 , 49.2 , 28.6 .
ir ( neat , cm ) : 36583162 ,
2966 , 2931 , 2796 , 1712 , 1597 , 1446 , 1307 , 1060 , 698 . lrms ( apci , m / z ) : calcd for c23h25no2 , 347.2 ; found , 347.8 .
the product was obtained from 1f using general procedure c and isolated as a red solid by aqueous
workup ( 275 mg , 87% ) .
h nmr ( 500 mhz , cdcl3 ) : 7.90 ( d , j = 3.1 hz , 1h ) , 7.867.80
( m , 2h ) , 7.547.49 ( m , 2h ) , 7.497.41 ( m , 3h ) , 7.38
( t , j = 7.6 hz , 2h ) , 3.433.36 ( m , 1h ) , 3.05
( dd , j = 17.4 , 7.1 hz , 2h ) , 2.712.57 ( m ,
4h ) , 2.09 ( s , 1h ) , 1.84 ( d , j = 6.4 hz , 4h ) .
c nmr ( 126 mhz , cdcl3 ) : 205.4 , 156.8 ,
143.6 , 142.2 , 131.2 , 129.1 , 128.7 , 128.6 , 127.5 , 127.3 , 124.6 , 81.7 ,
57.1 , 54.1 , 49.9 , 29.9 , 23.7 .
ir ( neat , cm ) : 36783163 ,
3059 , 3028 , 2966 , 2877 , 1716 , 1597 , 1558 , 1492 , 1446 , 1381 , 698 .
lrms
( apci , m / z ) : calcd for c22h23no2 , 333.2 ; found , 333.9 .
the product was obtained from 1 g using general procedure c. purification of the product was extremely
difficult due to its high polarity and instability .
the reaction also
resulted in a roughly 1.2:1 mix of diastereomers ( 14 mg , 56% ) .
hrms
( esi - tof , m / z ) : [ m + h ] calcd for c24h27no3 , 378.2069 ;
found , 378.2073 . the product was obtained from 1h using general procedure c and isolated as a pale yellow oil after
purification by column chromatography ( 4:1 hexane / etoac , 108 mg , 92% ) .
h nmr ( 500 mhz , cdcl3 ) : 7.79 ( d , j = 7.2 hz , 2h ) , 7.68 ( s , 1h ) , 7.477.40 ( m , 5h ) ,
7.39 ( d , j = 7.2 hz , 1h ) , 7.287.18 ( m , 4h ) ,
4.56 ( d , j = 6.4 hz , 1h ) , 4.18 ( s , 1h ) , 2.63 ( d , j = 14.0 hz , 1h ) , 2.51 ( d , j = 14.0 hz ,
2h ) , 2.33 ( d , j = 5.0 hz , 2h ) , 2.10 ( d , j = 5.2 hz , 2h ) , 1.58 ( s , 4h ) , 1.36 ( d , j = 6.4 hz ,
3h ) , 0.85 ( s , 9h ) , 0.11 ( d , j = 8.3 hz , 6h ) .
c nmr ( 126 mhz , cdcl3 ) : 205.2 , 157.6 ,
143.7 , 140.5 , 128.8 , 128.8 , 127.7 , 127.1 , 127.1 , 126.9 , 86.0 , 72.3 ,
59.6 , 56.5 , 55.7 , 25.9 , 23.9 , 20.3 , 18.0 , 3.6 , 4.2 .
hrms ( esi - tof , m / z ) : [ m + h ] calcd for c30h41no3si , 492.2934 ;
found , 492.2928 .
to a 1 m solution of 1a ( 33
mg ) in thf was added sodium methoxide ( 0.363 ml , 0.5 m in methanol )
dropwise at room temperature .
once the starting material was consumed
as observed by tlc , the reaction was quenched with water , and the
mixture was extracted with ether , dried with mgso4 , and
concentrated .
the product was isolated as a pale yellow oil and purified
by flash chromatography ( 4:1 hexane / etoac , 33 mg , 89% ) .
h nmr ( 500 mhz , cdcl3 ) : 7.89 ( s , 1h ) , 7.84 ( d , j = 7.3 hz , 2h ) , 7.487.34 ( m , 5h ) , 7.28 ( d , j = 6.2 hz , 3h ) , 3.163.04 ( m , 2h ) , 3.00 ( s , 3h ) ,
2.90 ( dd , j = 48.8 , 9.0 hz , 2h ) , 1.38 ( s , 3h ) .
c nmr ( 126 mhz , cdcl3 ) : 207.7 , 162.6 ,
141.1 , 139.8 , 130.7 , 129.0 , 128.7 , 127.9 , 127.8 , 127.0 , 126.6 , 83.7 ,
76.1 , 58.9 , 51.7 , 45.8 , 21.1 , 8.6 . hrms ( esi - tof , m / z ) : [ m + h ] calcd for c20h20o3 , 309.1491 ; found , 309.1496 . to a 1 m solution of 1a ( 33
mg ) in thf was added sodium ethanethiolate ( 0.015 mg ) in one portion
at room temperature .
once the starting material was consumed as observed
by tlc , the reaction was quenched with water , and the mixture was
extracted with ether , dried with mgso4 , and concentrated .
the product was isolated as a pale yellow oil and purified by flash
chromatography ( 4:1 hexane / etoac , 37 mg , 92% ) .
h nmr ( 500
mhz , cdcl3 ) : 8.04 ( s , 1h ) , 7.947.77 ( m ,
2h ) , 7.547.37 ( m , 5h ) , 7.397.17 ( m , 4h ) , 3.17 ( s ,
1h ) , 2.31 ( m , j = 58.0 , 49.6 , 12.7 hz , 4h ) , 1.43
( s , 3h ) , 1.09 ( t , j = 7.4 hz , 2h ) . c
nmr ( 126 mhz , cdcl3 ) : 207.0 , 162.9 , 141.1 , 140.0 ,
130.5 , 129.2 , 128.8 , 128.2 , 127.9 , 127.0 , 126.4 , 85.4 , 51.6 , 39.8 ,
28.3 , 23.9 , 14.7 .
hrms ( esi - tof , m / z ) : [ m + h ] calcd for c21h22o2s , 339.1419 ; found , 339.1416 . | ### Summary:
: the
1,6-conjugate addition of nucleophiles to dienyl diketones
produces either cyclopentenone or 2h - pyran products
with high selectivity through either nazarov ( 4 ) or 6
electrocyclization , respectively .
the outcome of the reaction is dependent
upon the nature of the nucleophile used .
nucleophiles that are anionic
or easily deprotonated exclusively produce cyclopentenones via nazarov
cyclization , whereas the neutral nucleophile dabco promotes 6
cyclization to afford 2h - pyrans .
experimental evidence
is presented for both retro-4 and -6 electrocyclization
in these systems , lending support to the bifurcated mechanistic hypothesis
proposed for these cyclizations . |
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: the study was designed as an open labeled clinical study using before and after intervention measurements to compare the two assessment methods .
it was approved by the regional bioethics committee according to national ethical codes of good clinical practice . during 4 years
, all the patients who have been paralyzed for 2 - 3 weeks were referred from three university hospitals to our study .
the main inclusion criterion for was long term rehabilitation which implies poor prognosis and gradual improvement .
forty patients with facial nerve degeneration were included in this study by standard electrodiagnostic tests .
ten patients quit due to having a surgery ( myectomy ) , discontinuing the treatment , or changing their residence .
others were treated by a three - session per week rehabilitation program for one year .
all patients were assessed before and after the treatment by two methods , namely photoshop assessment based on a previous study13 and fgs . in photoshop measurements ,
the patients faces were marked and digitally photographed in four different manners i.e. rest position , forehead wrinkle , snarl and smiling ( showing their teeth ) . pictures were transferred to a computer and vertical axes of resting photos ( as the reference pictures ) were determined using adobe photoshop . to draw the vertical axis ,
three points were marked on the picture including mid - point between the inside corners of the eyes , mid - point of the upper lip , and mid - point of chin . if the vertical line did not pass through these points , we tried to draw a line across the three points .
then , the shortest distance from the vertical line to each marker ( corners of lips ) was measured in the normal and impaired sides in the resting photos ( figure1 ) . to measure the differences between the marker positions at rest and posing various facial expressions , the prepared photos showing dynamic movements ( such as wrinkling , smiling , or snarling )
were put on the photos prepared at rest , i.e. the unchanged parts of the face were placed exactly on their counterparts . then , alteration of the marker positions was measured in millimeters by photoshop . after treating ,
paired t - test and spearman 's correlation were used in spss ( version 16 ) . marked points in photoshop .
thirty patients including 14 men and 16 women completed treatment for one year . there were 15 bell 's palsy cases , 11 trauma cases , and 4 acoustic and parotid tumor cases ( table2 ) .
the mean values of fgs before and after treatment were 35 25 and 67 24 , respectively .
. the mean ratio of the distance between the corner of the lip and the midline in the resting position in the impaired side compared to the sound side was 102% before the treatment and 105% after it .
the mean ratio of displacement of the eyebrow in the impaired side compared to the sound side before and after treatment was 79% and 93% , respectively .
the mean ratio of displacement of snarl in the impaired side in comparison with the sound side before and after treatment was 85% and 97% , respectively .
the mean ratio of the alteration of the corner of the lip in the impaired side in comparison with the sound side ( by showing teeth or smiling ) was 85% and 105% before and after the treatment , respectively .
all the differences before and after the treatment were statistically significant ( p < 0.05 , p < 0.001 , p < 0.001 , and p < 0.001 , respectively ) . mean values and standard deviations are shown in table 3 . mean values and standard deviations before and after the treatment . in photoshop assessment ,
the mean changes of face expression in the impaired side relative to the normal side in rest position and three main movements of face was 3.4 0.55 and 4.04 0.49 millimeter before and after the treatment , respectively .
spearman 's correlation coefficient between different values in the two methods was 0.66 ( p < 0.001 ) .
although h - b is a standard assessment measure , berg et al . reported that fgs to be at the same level.4 in the present study , we used fgs during rehabilitation treatment due to its high sensitivity to clinical changes3 and then compared photoshop results with fgs results .
the correlation coefficient of agreement between the two methods was 0.66 which can be an appropriate coefficient factor.14 although the sensory and autonomic branches of facial nerve would be damaged along with its motor branch , most assessments focused on the evaluation of motor branch ( because it is the main branch ) . on the other hand ,
it is clear that the only method of improving facial nerve palsy , in particular the cases of poor prognosis , is neuromuscular reeducation ( exercise therapy).1518 however , the efficacy is slow and gradual . during these improvement stages , there is a possibility to have contracture and overuse of both the impaired and normal sides causing asymmetry in the face to increase.19 therefore , finding a measurement tool which enables us to evaluate each part of face objectively to detect abnormalities would be of high value .
the main benefit of photoshop is that it can directly compare key points ( landmarks ) of the impaired side with the sound side by matching digital photos .
it can also show displacements or the amplitude of muscle contraction in the impaired and sound sides . in healthy people , due to face symmetry
, this ratio is equal to one.13 however , if it is more or less than 1 , analysis can reveal different states like contractures of the impaired side , muscle weakness of the impaired side , or overuse of the sound side muscles .
each landmark , representing a group of muscles used in one of the main movements of the face , could be considered and studied separately during treatment .
although this study was similar to sergeant 's study,11 it is simpler , could be conducted by any version of photoshop , and does nt need pixel subtraction .
it is also more accurate than nottingham system20 due to using software without requiring a manual approach which leads to more precise measurements .
, we can measure the amplitude of displacements in the main movements of the face during treatment and compare the differences with the sound side .
aap suggested and carried out the design and measurements , hz performed electrodiagnostic test and mh analyzed the data . | ### Summary:
: background : evaluating the function of facial nerve is essential in order to determine the influences of various treatment methods .
the aim of this study was to evaluate and assess the agreement of photoshop scaling system versus the facial grading system ( fgs).methods : in this semi - experimental study , thirty subjects with facial nerve paralysis were recruited .
the evaluation of all patients before and after the treatment was performed by fgs and photoshop measurements.results:the mean values of fgs before and after the treatment were 35 25 and 67 24 , respectively ( p < 0.001 ) . in photoshop assessment , mean changes of face expressions in the impaired side relative to the normal side in rest position and three main movements of the face were 3.4 0.55 and 4.04 0.49 millimeter before and after the treatment , respectively ( p < 0.001 ) .
spearman 's correlation coefficient between different values in the two methods was 0.66 ( p < 0.001).conclusions : evaluating the facial nerve palsy using photoshop was more objective than using fgs .
therefore , it may be recommended to use this method instead . |
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: revolutionary changes in the field of dentistry have been made possible by the combined use of computer - aided design and computer - aided manufacturing ( cad / cam ) technologies and scanners .
digital data of oral tissues can be directly utilized in design and manufacturing procedures , meaning that the production of prostheses is possible without the use of conventional materials and procedures .
digitization of oral tissues can be performed intra - orally by the direct scanning of oral tissues or extra - orally by scanning either models or impressions of oral tissues .
the scanning of impressions has the advantage of eliminating the model fabrication procedure , which is both time - consuming and a potential source of error .
however , it has been relatively under - used compared to other scanning modalities because of the elastic property of impression materials and scanning accessibility problems caused by the complex shape of the negative replicas .
three types of scanners are typically used in this field : mechanical scanners with a touch probe , laser scanners , and white light scanners,1,2 the most recently developed white light scanners show some features , which are advantageous for the scanning of impressions . as light scanners work without touching or pressing objects , the risk of deformation of elastic impressions
may be decreased compared to mechanical scanners.1 the performance of white light scanners is reportedly higher than that of laser scanners,2,3 because white light scanners analyze multiple stripe pattern,3 while laser scanners analyze a line pattern . while there are numerous investigations looking at scan performance on tooth models,1 - 9 studies of scan performance on impressions are scarce .
examined the performance of a touch - probe digitizer and concluded that mechanical digitizing can not be recommended for the direct digitizing of dental elastic impressions.10 persson et al . reported a discrepancy of less than 40 m when comparing digitized impressions made with a laser scanner with the stone replicas.8 few previous studies
have examined scan performance with regard to repeatability , and there is , therefore , insufficient evidence to support the use of these methods in clinical practice .
furthermore , there is one report on the performance of white light scanners for the polysiloxane impression material.11 however , no studies have confirmed the repeatability corresponding to silicon rubber impressions of abutment teeth type .
therefore , we aimed to evaluate the repeatability of the digitizing of silicon rubber impressions of abutment teeth using a white light scanner and compare differences in repeatability between different types of abutment teeth .
the hypothesis of this study was that there was no difference in repeatability of scanning values among silicon rubber abutment teeth impressions .
plastic tooth models of 3 representative types of upper teeth including the right canine , right first premolar , and right first molar were selected ( ag-3 , frasaco , gmbh , germany ) . a dental cad / cam system ( intellifit dental restoration system , sensable technologies inc .
, ma , usa ) with a haptic device ( sensable phantom desktop , sensable technologies inc .
, ma , usa ) , device for reading the 3-dimensional shapeis allowed to make direct contact with an apparatuspencil , which was used to recreate typical abutment tooth shapes . after scanning these tooth models ,
the haptic device performed preparation of abutment teeth providing axial clearance of 1 mm , occlusal and incisal clearance of 1.2 mm , an axial wall angle of 5 , and a deep chamfer margin design .
the cam system ( dt400 , doosan infracore co. , ltd , seoul , south korea ) was used to create titanium abutment teeth models using the milling machine to minimize abrasion during the impression procedure .
impressions of the prepared titanium abutment teeth were fabricated using extra - light body of a silicon rubber impression material ( aquasil ultra , dentsply , st .
the white light scanner ( identica , medit , seoul , korea ) equipped with 2 digital cameras that are placed at an angle of 15 to the object table were used in this experiment ( fig .
, the impression body was fixed on the table inside the white light scanner and the table was moved automatically in order to achieve the appropriate angles to obtain complete images .
various 3d images obtained from different angles were repeatedly rearranged and combined to get the complete 3d shape data of a stereolithography ( stl ) file format .
unnecessary parts of data including data from beyond the finishing margins , which seemed to be inaccurate , were deleted.7 the scanning procedure was repeated 8 times for each type of abutment tooth .
data from the first scan of each tooth type were used as the reference model , and the remaining 7 scans were compared with the designated reference model . before the comparison , 7 scans excluding the reference model were converted from stl format into the point cloud - ascii format using the copycad 7.350 sp3 ( delcamplc . ,
the reference model was aligned as a 3d - surface model and was superimposed with the point cloud data of the other scans using the powerinspect 2012 ( delcamplc . ,
discrepancies between the 2 were measured and displayed as color - difference maps ( fig . 3 , 4 and 5 ) .
after filtering the data , the amount of discrepancy of the whole tooth surface was measured in the form of absolute values .
mean and standard deviation ( sd ) of the overall discrepancy for 3 types of abutment teeth were calculated and statistically compared using the nonparametrickruskal - wallis test with post - hoc pairwise comparison by the wilcoxon rank - sum test , applying an adjusted alpha level ( 0.17 = 0.05 over 3 , number of comparisons ) .
all the statistical procedures were performed with spss version 20.0 ( spss inc . , chicago , il , usa ) .
in addition , a qualitative analysis was performed to produce the color - difference maps for canine , premolar and molar .
point numbers 2095 , 2071 and 3803 were selected from the point cloud for the quantitative analytic procedure .
these were filtered by an interval of 15 m among all the points of scanned point cloud 26037 , 24567 and 44702 for the canine , premolar and molar teeth , respectively .
the color - difference maps allowed qualitative visual assessment , where green points indicate an exact fit , a positive discrepancy ( greater than the reference model ) is shown as yellow or red points , and a negative discrepancy ( smaller than the reference model ) as turquoise or blue points ( fig . 3 , 4 and 5 ) .
table 1 shows the means and standard deviations of the 7 scans for the 3 types of abutment teeth impressions ( n = 8 per type ) .
the means of the discrepancies for each tooth type were 6.2 m ( 95% confidence interval [ ci ] , 5.4 - 7.1 ) , 6.4 m ( 95% ci , 5.2 - 7.6 ) , and 8.8 m ( 95% ci , 8.2 - 9.4 ) , for the canine , premolar and molar teeth , respectively .
the mean discrepancy of the molar scans was significantly higher than those of either the canine or premolar scans ( table 2 ) .
the variation in discrepancies ( as mean [ sd ] ) in the scans of the premolar tooth , which had a relatively longer axis and smaller diameter , were significantly larger than variation in the scans of the canine and molar teeth : 26.7 m ( 95% ci , 19.6 - 33.7 ) ; 16.2 m ( 95% ci , 15.2 - 17.3 ) ; and 14.0 m ( 95% ci , 12.3 - 15.6 ) , respectively . as a qualitative analysis ,
the color - difference maps of the canine scans were predominantly green indicating an exact fit between scans and the reference model ; however , red or blue colors , indicating positive or negative discrepancies , can be seen on the labial surface of some scans ( especially a and b ) , and the axial surface of most canine scans ( fig .
3 ) . in maps of the premolar scans , though most of the occlusal surface is green , an area of blue and some red is seen , particularly in the axial wall region ( fig .
whilst the maps of the molar scans are generally green , some blue or red is seen on the axial surface ( fig .
these findings demonstrate excellent repeatability of the white light scanner in digitizing of silicon rubber impressions of 3 representative types of abutment teeth - canine , premolar and molar .
the low mean discrepancy , ranging from 6.3 m to 8.8 m , is much smaller than those in previous reports .
for example , mean positive deviations between 27 m and 28 m were achieved with mechanical digitization of an impression body using a touch probe scanner10 and a discrepancy of 40 m has been reported when a laser scanner was used.8 our results are similar to those described in a study where conventional impression and production of stone casts , which is currently considered as the gold standard , produced a mean deviation of approximately 3 m.12 although there was a statistically significant difference between the mean discrepancies for the different tooth types , the maximum difference of 2.5 m ( 6.3 m-8.8 m ) is unlikely to be clinically significant . in this study , there was greater variation in the premolar scans than in scans of the other tooth types .
this may be related to the long and narrow shape of premolar impression ( average axial length , 4.47 mm ; buccal lingual width , 6.18 mm ; and mesio - distal width , 3.60 mm ) which was difficult to reach by the light beam ( fig .
the notion that the accuracy of the scan is impaired by accessibility of the light beam is supported by the finding of the greatest discrepancies being at the axial walls in all types of teeth .
in contrast to the digitization of models , digitizing of impressions had more difficulties in applying for practical procedure .
it has been reported that mechanical tactile digitization using a probe is inaccurate , mainly owing to the easily deformable nature of the rubber impression materials during probing.10 although one study concluded that impressions could be digitized with a high repeatability by a laser scanner , the 40 m discrepancy reported may be inappropriately high for clinical use.8 to the best of our knowledge , our findings , which are comparable to those reported with conventional methods , are the first to support the use of a white light scanner in digitization of rubber impressions for a clinical procedure .
for example , the accuracy of white light scanners is generally regarded to be superior to that of laser scanners in which : ( 1 ) error is inevitable because of the " speckle effect " , which originates from the laser beam ; and ( 2 ) the laser beam is only projected on to the object once to obtain 3d coordinates from the image.13 the superior accuracy of white light scanners is mainly due to repeated rearrangement and recombination of the 3d images , which are obtained from more than 1 angle , to get a complete 3d shape data.14 white light scanners measure objects at a speed of 3 mhz / s , which is much faster than laser scanners with speeds of 10 - 500 khz / s , and this may save time in the clinic.9 however , there are some limitations in the performance of white light scanners .
because of the straight linear nature of the light projection , there may be areas of shadow when scanning impressions with slender , long negative forms or acute apical angles , as seen in some anterior teeth .
in this study , most discrepancies , as can be seen clearly on the color - difference maps , were observed on the vertical axial walls of the impressions of abutment teeth .
further study is needed to enhance the accessibility of the light beam to potentially shadowed areas , possibly by making more intricate movement of platform tables possible , or by increasing the numbers of cameras .
it is important to consider that the high repeatability achieved in this study may reflect the use of idealized models in an in vitro environment . in vivo studies
are needed to demonstrate that a similar result can be achieved by using white light scanners in a clinical setting : using prepared abutment teeth in the oral cavity and taking impressions in the presence of soft tissues and body fluids .
the repeatability of the digitizing abutment teeth 's silicon rubber impressions by using a white light scanner was improved , compared to that with a laser scanner , showing only a low mean discrepancy between 6.3 m and 8.9 m , which was in an clinically acceptable range .
premolar impression with a long and narrow shape showed a significantly larger discrepancy than canine and molar impressions .
further study is needed to increase the digitizing performance of the white light scanner for deep and slender impressions . | ### Summary:
: purposethe aim of this study was to evaluate the repeatability of the digitizing of silicon rubber impressions of abutment teeth by using a white light scanner and compare differences in repeatability between different abutment teeth types.materials and methodssilicon rubber impressions of a canine , premolar , and molar tooth were each digitized 8 times using a white light scanner , and 3d surface models were created using the point clouds .
the size of any discrepancy between each model and the corresponding reference tooth were measured , and the distribution of these values was analyzed by an inspection software ( powerinspect 2012 , delcamplc . ,
birmingham , uk ) .
absolute values of discrepancies were analyzed by the kruskal - wallis test and multiple comparisons ( =.05).resultsthe discrepancy between the impressions for the canine , premolar , and molar teeth were 6.3 m ( 95% confidence interval [ ci ] , 5.4 - 7.2 ) , 6.4 m ( 95% ci , 5.3 - 7.6 ) , and 8.9 m ( 95% ci , 8.2 - 9.5 ) , respectively .
the discrepancy of the molar tooth impression was significantly higher than that of other tooth types .
the largest variation ( as mean [ sd ] ) in discrepancies was seen in the premolar tooth impression scans : 26.7 m ( 95% ci , 19.7 - 33.8 ) ; followed by canine and molar teeth impressions , 16.3 m ( 95% ci , 15.3 - 17.3 ) , and 14.0 m ( 95% ci , 12.3 - 15.7 ) , respectively.conclusionthe repeatability of the digitizing abutment teeth 's silicon rubber impressions by using a white light scanner was improved compared to that with a laser scanner , showing only a low mean discrepancy between 6.3 m and 8.9 m , which was in an clinically acceptable range .
premolar impression with a long and narrow shape showed a significantly larger discrepancy than canine and molar impressions .
further work is needed to increase the digitizing performance of the white light scanner for deep and slender impressions . |
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: migraine is a complex disorder caused by a combination of genetic and environmental factors . at present
it is possible to define this disease as a complex spectrum including features such as craniofacial pain , autonomic dysfunctions , mood disregulations and spreading cortical disturbance represented by both positive and negative aura phenomena [ 15 ] .
migraine diagnosis is based on anamnesis , a record patient s symptomatology and the exclusion of secondary causes .
a more precise determination of familial aggregation appears in the calculation of disease relative risk of the population in specified groups of relatives .
epidemiological surveys found that first - degree relatives of probands displayed a much increased risk of developing the disorder of proband as compared to the general population .
the risk increase in close relatives obviously does not imply the pathology s manifestation but only the sharing of a genotypic pattern , which determines the outbreak of clinical manifestations after environmental stimuli of different kinds ( stress factors , food , smells ) . at present , the international headache society ( ihs ) classification recognises some phenotypical features attributing them to diagnostic subtypes .
however , patients with the same diagnosis present a symptomatological pattern ( type of pain , pain location , accompanying symptoms ) underlining a great variability of expressions . according to this view , migraine could represent a syndrome whose clinical components are the reflection of specific loci expressions , independently influencing susceptibility to migraine . the family aggregation of migraine with aura ( ma ) and migraine without aura ( mo ) evidence that there is a genetic component as the basis of migraine susceptibility . in a finnish study involving 2690 monozygotic and 5497 dizygotic twin pairs ,
the genetic component ranged from 34% to 51% in different migraine types , without remarkable variations with respect to gender .
similar results have been obtained in several studies on adult twin pairs [ 810 ] .
although family and twin studies show that there is a genetic component in migraine , no genes predisposing to common forms of the disorder have been identified . at present , several loci 4q21q24 , 5q21 , 6p12.2p21.1 , 11q24 , 14q21.2q22.3 and 15q11q13 linked to common forms of migraine with evidence of linkage have been reported .
several genes were described involved in migraine in many studies , but always with controversial results . in a more general scenario ,
the efficacy of a drug therapy and the occurrence of adverse reactions are a direct consequence of individual variability .
most of this variation in individual response is genetically determined and is the object of the study of pharmacogenetics .
at present , the best genetic evidence providing molecular insight into migraine comes from the mutations that have been detected in a rare mendelian form of migraine , named familial hemiplegic migraine ( fhm ) .
this represents the only gene - related headache disorder that has been identified so far .
fhm is a rare subtype of ma with an autosomal dominant inheritance pattern ; it is a primary headache form characterised by motor weakness ( transient hemiparesis or hemiplegia ) during the aura phase of migraine attacks , and similar episodes in at least one first- or second - degree family member .
mutations in three different genes have been identified in fhm families : cacna1a gene , involved in fhm type 1 ( fhm1 ) , localised to chromosome 19p13 , encoding for the 1a subunit of the neuronal voltage - gated calcium channel cav2.1 ( neuronal p / q - type calcium channel ) ; atp1a2 gene localised to chromosome 1q2123 , implicated in fhm type 2 ( fhm2 ) encoding for the 2 subunit of the na , k - atpase isoform ; and scn1a gene localised to chromosome 2q24 , implicated in fhm type 3 ( fhm3 ) , encoding a neuronal voltage - gated sodium channel ( nav1.1 ) .
patients affected by fhm present a symptomatic range of which migraine constitutes just one aspect . in fact , some fhm families can present with only cerebellar degeneration or seizures and in the same way several genes , isolated in fhm families , are also involved in other neurological disorders with an autosomal dominant inheritance pattern such as episodic ataxia type 2 and spinocerebellar ataxia type 6 [ 15 , 16 ] .
functional studies of fhm support the hypothesis that ion transport dysfunction is one of the main factors determining susceptibility of the brain to migraine attacks .
new therapeutic strategies are aimed at controlling cortical hyperexcitability to prevent clinical manifestations : the protracted administration of some anti - migraine drugs would appear to change the expression of the genes .
thus , the genes involved in fhm pathogenesis could be possible therapeutic targets , although the many studies investigating the role of cacna1a gene in common forms of migraine have produced contradictory results [ 17 , 18 ] .
more generally , the role of fhm genes codifying for neuronal channels as cav2.1 , nav1 , na and k - atpase at the cerebral level constitute a possible object of pharmacogenomic research .
this is true for fhm , but it seems to be far from a common form of migraine .
although the three fhm genes represent the main candidate genes for understanding migraine pathogenesis also in the more common forms , several case - control association studies have indicated additional susceptibility genes implicated in migraine with and without aura [ 2027 ] .
most of the genes identified to be associated to migraine need to be confirmed by further studies , because of the heterogeneity of the sample in terms of diagnosis , ethnic background and sample size , before being able to consider them as predisposing genes .
the c677 t polymorphism of the methylenetetrahydrofolate reductase ( mthfr ) gene has been suggested to be associated with ma in several populations , although recently in a large cohort of patients and controls this association failed to be verified .
nevertheless the same study does not confirm the positive association of the variants of esr1 ( oestrogen receptor gene ) with the migraine precedent described [ 20 , 29 ] .
mccarthy et al . identified five single - nucleotide polymorphisms ( snps ) within the insulin receptor gene that showed a significant association with migraine , suggesting possible functions for the insulin receptor in the pathogenesis of this disease .
the association between common migraine forms and the hla system today represents one of the most investigated aspects . in a group of italian migraine patients , martelletti et al
. showed that the frequency of hla dr2 antigen decreased in the ma group when compared with both the mo and the control group .
these results seemed to support the hypothesis of a protective role of dr2 antigen in ma and provided an additional basis for the proposed differences within mo and ma . in a subsequent study conducted in a larger cohort of italian patients ,
the frequency of the hla drb112 allele was found to be decreased in patients with migraine while the drb1 * 16 allele , coding for hla dr2 antigen , was significantly increased in comparison with controls .
however once patients were divided into subgroups , mo patients presented a significant increase of the hladrb * 16 allele .
the discrepancy observed about drb112 frequency in these studies can be due to the different sizes of the two samples , but both studies observed that the frequency of hla dr2 was different between ma and mo groups , emphasising that there is a different genetic background in the two subtypes of migraine . a possible explanation for the association of hla drb1 alleles with migraine lies in the fact that this locus may be involved in susceptibility or may be in linkage disequilibrium with other genes , because the drb1 gene is located on chromosome 6p21 , within the hla class ii region .
recently , a significant association has been found between migraine and the polymorphisms of two genes : tumour necrosis factor- ( tnfa ) and lymphotoxin ( tnfb ) , localised in the hla class iii region .
tnf- is a proinflammatory cytokine involved in both the outset and regulation of inflammatory response .
the association of the tnfa308g / a polymorphism with the occurrence of migraine has been shown only in mo patients ; patients homozygous for the g allele present a higher risk of developing the disease .
this suggests that the tnfa gene or a locus in linkage disequilibrium may be implicated in the risk of disorder modulation .
tnfb codifies for a cytokine involved in the formation of secondary lymphoid organs during development and playing a role in apoptosis .
the nco1 polymorphism in the first intron of the tnfb gene ( tnfb*1 and tnfb*2 alleles ) in migraine has been investigated .
the frequency of the tfnb*2 allele is significantly higher in mo patients , as compared with the control group , but no significant differences have been found between ma patients and controls .
this evidence suggests a possible role of lymphotoxin in the genetic background of migraine .
given the possible role played by tnf genes and hla , the task of the cytotoxic t lymphocyte antigen 4 ( ctla-4 ) has also been explored as they are negative regulators of tcell proliferation and therefore of cytokine production .
nevertheless , the results of the survey on ctla-4 polymorphism 49 a / g intron 1 failed to identify any positive association in mo and ma patients .
another aspect that has been investigated is the relationship between genetic factors and the possibility of developing chronic forms of headache ( chronic daily headache , cdh ) . in ma patients , peroutka et al .
explored the ncoi c / t polymorphism ( his313his ) in exon 6 of the dopamine receptor 2 gene ( drd2 ) , located on chromosome 11q22 .
the patients with the drd2 ncoi c / c genotype presented a higher incidence of ma episodes , major depression and anxiety disorders in comparison with individuals with a t allele .
. showed an increase in the frequency of migraine attacks in patients with angiotensin - converting enzyme ( ace ) allele d polymorphisms localised in 17q23 .
cdh patients are predisposed to developing drug abuse ( medication overuse headache , moh ) .
in these patients a role of the dopamine metabolism - related gene has been hypothesised .
polymorphisms of the dopamine transporter ( dat ) gene , which encodes a protein responsible for presynaptic uptake of dopamine , are involved in the development of drug abuse .
polymorphisms of the dopamine receptor 4 ( drd4 ) gene are implicated in the predisposition to episodic migraine attacks but not in drug abuse . the wolfram gene ( wfs1 )
is located on chromosome 4p16.1 and codifies for wolframin , a transmembrane protein expressed in all cell types , in the brain predominantly in the limbic system or in structures closely related to it .
mutations in this gene are associated to wolfram syndrome , a neurodegenerative disorder related to diabetes mellitus , diabetes insipidus , hearing loss , progressive blindness and a heterogeneous combination of psychiatric disorders .
thus , in moh patients that show both an increase in abuse of symptomatic drugs and major psychiatric disorders , the his611arg polymorphism of the wfs1 gene has been investigated .
individuals harbouring the r / r ( arg / arg ) genotype showed significantly higher monthly drug consumption and more severe depressive symptoms than non - r / r individuals .
the efficacy of a drug therapy and the occurrence of adverse reactions are a direct consequence of individual variability , which is a complex trait depending on both genetic background ( the genetic component present in each of us ) and environmental factors [ 35 , 36 ] .
most of this variation in individual response is genetically determined and is the object of the study of pharmacogenetics .
genetic factors influence the pharmacokinetics ( absorption , distribution , metabolism and excretion of the drug ) and pharmacodynamics ( drug effect ) ; the genetic variability determines the different ways in which a drug exerts its effect , for example by influencing the link with the target of the drug on which it acts ; moreover it could make receptors , enzymes and proteins , involved in metabolism of a drug , different in structure and function .
pharmacogenomics deals with the dna and rna variations related to a drug response ; the gene expression study can be used as a diagnostic tool to predict whether a patient will respond to a drug well or badly , or not at all [ 3739 ] .
the realistic promises of migraine pharmacogenomic - based therapies are the advent of individually - tailored drugs and the potential to reduce costs not only in terms of money but also in human suffering and lost productivity . nowadays a great deal of scientific literature regarding genetic studies applied to migraine treatment can be found [ 4144 ] .
pharmacogenetic information might be applied for identification of cases where certain drugs are simply not effective .
in fact , pharmacogenomic factors can modify the drug response of an organism through a pharmacokinetic and pharmacodynamic action .
the enzymes that metabolise drugs could present polymorphisms able to profoundly influence the dose - response relation among different patients .
genetic profiling of predisposition to migraine should facilitate the development of more effective diagnostic and therapeutic applications .
possible targets of pharmacogenomic research are both the serotoninergic and dopaminergic systems [ 38 , 45 ] .
the role of the serotoninergic system is suggested by the use of triptans in acute treatment .
triptans are drugs that act selectively as agonists on 5-ht1b/1d receptors producing vasoconstriction of meningial vessels as well as direct action on central pathways of trigeminal transmission [ 46 , 47 ] . in several studies
the relationship between polymorphisms of 5-ht1b receptors and clinical response to sumatriptan has been investigated , however without being able to establish an unquestionable link between them .
the serotoninergic system s role is also suggested by the use of antidepressants , such as selective serotonin reuptake inhibitor ( ssri ) , in prophylaxis treatment .
several studies indicate that hypersensitivity of the dopaminergic system is implicated in the pathogenesis of migraine .
in fact , as reported above , an association between drd2 gene and ma has been demonstrated [ 44 , 51 ] .
moreover , some accompanying symptoms of migraine are mediated by the dopaminergic system ( nausea , vomiting ) , underlining a possible role in clinical susceptibility to migraine .
in terms of drug efficacy and toxicity , individual variability is associated with genetic variations in absorption and distribution into the site of action , or more generally in drug metabolism . in the same way
the field can be extended to genes encoding drug transporters , drug receptors and other drug targets .
however , the majority of genetic factors involved in the variability of therapeutic effects and/or adverse drug response ( adr ) are unknown and so far no molecular genetic clues have been identified for the more common types of primary headaches . in recent years it has become clear that genetic factors could greatly modify drug responses as well as increase the risk of occurrence of adr . in a review that analysed studies carried out between 1995 and 2000 , the association between adr of some drugs and the presence of at least one enzyme with a variant allele known to cause poor metabolism has been evidenced .
these results suggest that a therapy based on genetic information could turn out to be clinically effective in the reduction of adverse outcomes .
if genetic information such as the allelic variants of enzymes involved in the metabolism was known , the choice of a therapy could be effectuated more precisely .
linkage studies failed to identify a valid model for the study of common forms of migraine .
until now , only one or few snps have been analysed in most studies of genetic association in migraine . this approach has often led to conflicting results , as a consequence of using both different protocols and heterogeneous samples regarding ethnicity and size .
the development of the international hapmap project could also provide a powerful tool for identification of candidate genes in this complex disease .
these haplotypes in which snps are grouped in linkage disequilibrium blocks ( tag snp ) , identified by the hapmap project , can be used for the association study of genes as candidates for the presence of common variants that confer susceptibility to the disease . if a genetic variant on an ancestral chromosome increases risk of disease , the related ancestral haplotype will also be associated to the disease .
so , tag snp can be used as markers to identify the location of the disease variant , reducing genotyping costs and moreover standardising study design . in the future , in addition to targeting a patient s drug concentrations within a therapeutic range , pharmacists are likely to be making dosage recommendations for individual drugs on the basis of the individual patient s genotype . as we enter the era of personalised drug therapy , we will be able to identify not only the best drug to be administered to a particular patient , but also the most effective and safest dosage from the outset of therapy
. other advantages of genotyping over traditional therapeutic drug monitoring include the discovery of new targets for migraine therapy .
identification of polymorphisms and genetic biomarkers should help us to better understand migraine pathology and therefore choose the most effective treatments for migraine patients . | ### Summary:
: migraine is a complex disorder caused by a combination of genetic and environmental factors.although family and twin studies show that there is a genetic component in migraine , no genes predisposing to common forms of the disorder , migraine with and without aura , have been identified .
patients with migraine respond differently to a given drug administered .
the efficacy of therapy and the occurrence of adverse drug response are a consequence of individual variability .
genetic profiling of predisposition to migraine should facilitate the development of more effective diagnostic and therapeutic applications .
the development of international hap map project could provide a powerful tool for identification of the candidate genes in this complex disease and pharmacogenomics research could be the promise for individualized treatments and prevention of adverse drug response . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: benign neoplasms comprise less than 10% of tumors involving the trachea and main stem bronchi .
leiomyoma of the airways is a rare benign tumor , usually described as being a solitary tumor .
primary pulmonary leiomyoma are extremely uncommon both in adults and children , constituting approximately 2% of benign lung tumors .
the affected patients usually have respiratory symptoms due to partial or complete airway obstruction which may simulate asthma or be complicated with bronchiectasis and recurrent pulmonary infection .
only one third of primary pulmonary leiomyomas are endobronchial in location , literature on primary endobronchial leiomyomas is scarce , with a 2009 review reporting only 108 cases .
the majority of lung leiomyomas , approximately 51% , are located in the parenchyma , endobronchial accounts for 33% and trachea for the remaining 16% .
a 42 years old , housewife presented with history of breathlessness on exertion and non productive cough since 4 months .
there was also history of mild fever inter - mittently . at the time of presentation patient was already on steroids for the last 10 days without any relief of symptoms . on examination she was afebrile .
the patient 's laboratory findings were as follows : hb-13.0 gm / dl , packed cell volume-41.0% .
total leukocyte count-9800/cumm , polymorhs-65% , lymphocytes-30% , eosinophils-02% , monocytes-03% , platelets-3.325 lacs / cumm , erythrocyte sedimentation rate-30mm / hr .
rheumatoid arthiritis factor , antinuclear antibody profile : c- anca , p- anca , anti - double stranded dna were all negative .
other blood investigations like liver function tests , renal function tests , thyroid profiles were all within normal range .
high resolution computed tomography ( hrct ) thorax [ figures 1 and 2 ] showed areas of air space opacification , interlobular and subpleural interstitial thickening noted in both lower lobes and right middle lobe .
were seen obstructing the apicoposterior segments of the right upper lobe [ figure 3a c ] .
the tumor was composed of bundles and whorls of spindle shaped cells with monomorphous fusiform nuclei and acidophilic cytoplasm without cytonuclear atypia , mitotic cells or areas of necrosis .
ultrasonography ( usg ) abdomen and complete gynecological examination did not reveal any evidence of a leiomyoma in the uterus or elsewhere .
immunohistochemistry was consistent with a myogenic tumor as it showed diffuse cytoplasmic reactivity for smooth muscle actin and desmin .
inspite of extensive search no literature regarding endobronchial leiomyoma with a coexisting interstitial pneumonitis could be found .
we managed the two conditions as different unrelated entities and patient was treated with steroids and antibiotics to which she responded very well in two weeks time . on review
there was near complete resolution of reticulonodular shadows in the lower zones seen at the initial visit .
oncology opinion was taken but as tumor was benign and had caused no significant endobronchial obstruction with not even sub - segmental collapse conservative management was advised while keeping the patient on regular follow up .
hrct thorax : showing - relatively normal upper lobes hrct thorax : showing - findings of air space opacification , centrilobular nodules and interstitial thickening mainly involving both lower lobes bronchoscopy image showing leiomyoma bronchoscopy image showing leiomyoma bronchoscopy image showing leiomyoma submucosal tumour composed of cells arranged in whorls and fascicles , monomorphic cells with spindly nuclei .
the bronchial tree is a most unusual site for a leiomyoma that too with concomitant interstitial pneumonitis .
it is common in the uterus , but very uncommon in the smooth muscles of extrauterine sites . when they are located in other than well - known locations , i.e. , oesophagus , small intestine or uterus , generally they are symptom free and detected by chance while performing routine check - up measures or diagnostic studies for other pathologies
. other locations of leiomyomas include thyroid , extrapleural chest wall , lungs , trachea and bronchi . till date
bronchial leiomyomas are benign tumors which predominantly occur in the fourth decade of life with female preponderance .
bronchial leiomyomas are thought to arise from the smooth muscle cells of the bronchial wall and the interstium or from the smooth muscles of the arterioles .
the definitive diagnosis can be made by bronchoscopy which enables us to visualise the lesion as well as take samples for hisopathological analysis .
patients with bronchial leiomyomas usually have respiratory symptoms due to partial or complete obstruction of the affected bronchus .
shortness of breath , chest pain , fever , chronic and recurrent episodes of pneumonitis in the same part of the lung
development of smooth muscle neoplasm have reported in different conditions with immune deficiency , including acquired immunodeficiency syndrome ( aids ) , particularly in children with cellular immune deficiencies and malignant lymphoma epstein- barr virus has also been detected in almost all aids- related smooth muscle neoplasms and in the reported case of bronchial leiomyoma in a boy with cellular immunodeficiency .
they have been reported in the literature mainly in children with congenital hiv ; however , they can also be seen in adults the association of leiomyoma and hiv infection has been reported in a boy with a cellular immunodeficiency , who had endobronchial leiomyoma . a case of an ebv -associated endobronchial leiomyoma
histological criteria , including cellularity , mitotic activity , and pleomorphism have been proposed to differentiate between benign and malignant smooth muscle neoplasms .
the principle criterion is mitotic activity that should be less than 5 per 50 hpf . in the present case
other treatment options include resection , highly active antiretroviral ( haart ) in cases of aids and less often chemotherapy and radiotherapy .
surgery remains the mainstay of treatment for bronchial leiomyoma , type of surgery depending upon the location of the tumour .
localized resection , bronchotomy , segmental resection or bronchoscopic removals are different modes of surgery employed to treat the tumour . yag laser or electrocautery can be used via bronchoscope to resect the tumor .
the definitive diagnosis can be made by bronchoscopy which enables us to visualize the lesion as well as take samples for hisopathological analysis . | ### Summary:
: an endobronchial leiomyoma is a rare tumor of the bronchial tree .
very few cases have been reported in literature .
leiomyomas account for less than 2% of all benign lung tumors .
only one third is endobronchial in location , usually presenting as primary solitary lesions and airway obstruction findings .
literature on primary endobronchial leiomyomas is therefore scarce , with a few more than 100 cases being reported .
these tumors arise from the smooth muscle of the bronchial tree .
symptomatology is based on the degree of endoluminal bronchial obstruction and surgical resection has generally been the mainstay of treatment .
we describe a case of endobronchial leiomyoma in a 42 year old female .
a diagnosis of primary endobronchial leiomyoma was made on the basis of histopathology and immunohistochemistry .
rarity of this tumor in the bronchial tree with coexisting interstitial peumonitis urges us to report this case . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the treatment of edentulous areas with ridge defects poses a challenging task for the dentist . a variety of factors such as quality and quantity of existing contiguous hard and soft tissues , systemic condition and economic status of the patient play a significant role in treatment planning , clinical outcome and prognosis .
management of such cases involves a wide range of treatment options comprising mainly of soft tissue augmentation ( employed mainly for siebert 's class i defects ) , bone augmentation techniques by inlay and onlay grafting ( mainly for siebert 's class ii and iii defects ) and combination technique incorporating soft tissue and bone augmentation .
the clinical situations in which surgical augmentation can not be carried out on grounds of the systemic condition of the patients or their reluctance for the surgical procedure mandate the use of alternative treatment protocols .
such alternate treatment protocols include removable partial dentures , fixed partial dentures with gingival colored porcelain and fixed - removable partial dentures known as andrews bridge .
this case report presents the restoration of a seibert 's class iii ridge defect by modified andrews bridge in a 32-year - old patient .
a 32-year - old male reported with a chief complaint of unesthetic appearance of the face due to depression in the lip region on the left side of the face .
extra orally , two scars and a prominent depression in lower lip region were noticeable on the left side of the face . on intraoral examination , mandibular anterior and premolar teeth were missing and a bony defect ( 12 mm 19 mm ) with flabby tissue at the base was present at the respective region [ figure 1a ] .
the complete case history of the patient was taken , which revealed that the patient had undergone treatment for comminuted mandibular fracture in symphseal - parasymphyseal region on the left side of face 3 years back .
this segment of the mandible along with five teeth ( mandibular anteriors and premolars ) was removed during open reduction of the fracture followed by placement of titanium reconstruction plate .
the intraoral closure of the defect was done by placing the temporal flap over the defect .
the relative positions of the two mandibular segments and the reconstruction plate could be clearly appreciated on orthopantogram [ figure 1 ] .
the tissues in the defect region were 12 mm below the cervical margins of the adjacent teeth , attributing it as a siebert 's class iii defect [ figure 1b ] .
the various treatment modalities were thoroughly explained to the patient . considering the reluctance for the surgical procedure and economic status of the patient
the modification planned was to replace the costlier prefabricated bar and sleeve attachment of conventional andrews system with two small disc shaped magnets .
the advantages and disadvantages were clearly explained to the patient and informed consent was taken .
the step by step procedure is as follows : ( a ) preoperative orthopantogram ( b ) preoperative interocclusal view showing siebert 's class iii defect
diagnostic impressions were made and casts were preparedthe selected abutment teeth ( 41 , 36 ) were prepared for metal ceramic restorations .
the gingival retraction was done using gingival retraction cord ( ultrapak ) and putty wash impression ( express std putty 3 m , espe , usa and express light body std quick wash , 3 m espe , usa ) was made .
provisional crowns ( protemp ii , 3 m espe , usa ) were cemented on both the prepared teeththe maxillary and mandibular casts were mounted , and the wax pattern was fabricated in blue inlay wax ( bego , usa ) comprising of a rectangular bar connecting copings on both the prepared teeth .
the pattern was casted in nickel chrome alloy ( wiron 99 , bego , usa)the cast metal framework was tried in patient and checked for any impingement of the basal tissuesthe framework was again tried in after application of porcelain ( ceramco-3 , dentsply , usa ) . afterwards , the framework was reseated on the cast and a self - polymerizing clear acrylic ( dpi , india ) flange was fabricated from the bar in the framework till the soft tissues on the base of the defect .
the tissue surface of the flange simulated the sanitary pontic design [ figure 2 ] .
a magnet ( ndfeb magnet , ni - plated disc shaped magnet 2 mm 1.5 mm in size , techtone electronics , mumbai , india ) was placed in buccolingual and mesiodistal center of the lingual surface of this flange [ figure 3a]the framework was cemented in vivo with temporary cement ( rely - x temp , 3 m espe , usa ) .
an impression of the mandibular arch after cementation of the framework was made using irreversible hydrocolloid ( algitex , dpi , india ) .
the cast was poured ( kalstone , kalhabhai , india ) and undercuts were blocked .
the cast thus obtained was used for the fabrication of removable component of the prosthesismounting of the casts was followed by teeth arrangement and esthetic try inacrylization of prosthesis was done with heat cure acrylic resin ( dpi , india)the undercuts in the prosthesis were removed before insertion .
a counter magnet was placed on intaglio surface of lingual flange of the removable part of the prosthesis corresponding to the magnet on fixed part of the prosthesis [ figure 3a ] .
the framework was cemented permanently , and the removable component was placed [ figure 3b]the technique of insertion and removal of the prosthesis was taught to the patient . oral hygiene instructions and recall schedule
diagnostic impressions were made and casts were prepared the selected abutment teeth ( 41 , 36 ) were prepared for metal ceramic restorations .
the gingival retraction was done using gingival retraction cord ( ultrapak ) and putty wash impression ( express std putty 3 m , espe , usa and express light body std quick wash , 3 m espe , usa ) was made .
provisional crowns ( protemp ii , 3 m espe , usa ) were cemented on both the prepared teeth the maxillary and mandibular casts were mounted , and the wax pattern was fabricated in blue inlay wax ( bego , usa ) comprising of a rectangular bar connecting copings on both the prepared teeth .
the pattern was casted in nickel chrome alloy ( wiron 99 , bego , usa ) the cast metal framework was tried in patient and checked for any impingement of the basal tissues the framework was again tried in after application of porcelain ( ceramco-3 , dentsply , usa ) . afterwards , the framework was reseated on the cast and a self - polymerizing clear acrylic ( dpi , india ) flange was fabricated from the bar in the framework till the soft tissues on the base of the defect .
the tissue surface of the flange simulated the sanitary pontic design [ figure 2 ] .
a magnet ( ndfeb magnet , ni - plated disc shaped magnet 2 mm 1.5 mm in size , techtone electronics , mumbai , india ) was placed in buccolingual and mesiodistal center of the lingual surface of this flange [ figure 3a ] the framework was cemented in vivo with temporary cement ( rely - x temp , 3 m espe , usa ) .
an impression of the mandibular arch after cementation of the framework was made using irreversible hydrocolloid ( algitex , dpi , india ) .
the cast was poured ( kalstone , kalhabhai , india ) and undercuts were blocked .
the cast thus obtained was used for the fabrication of removable component of the prosthesis mounting of the casts was followed by teeth arrangement and esthetic try in acrylization of prosthesis was done with heat cure acrylic resin ( dpi , india ) the undercuts in the prosthesis were removed before insertion .
a counter magnet was placed on intaglio surface of lingual flange of the removable part of the prosthesis corresponding to the magnet on fixed part of the prosthesis [ figure 3a ] .
the framework was cemented permanently , and the removable component was placed [ figure 3b ] the technique of insertion and removal of the prosthesis was taught to the patient . oral hygiene instructions and recall schedule
fixed component with acrylic flange fabricated and magnet placed in it ( a ) counter magnet placed in the removable component ( b ) postoperative view showing removable component placed over the cemented fixed component
the management of extensive ridge defect ( siebert 's class iii ) by a fixed - removable partial denture in a mandibular fracture patient has been explained .
the andrews system is basically composed of two components : fixed component ( retainers on abutments joined by bar ) and removable component . the conventional andrews system requires a castable bar ( incorporated in the fixed component ) and sleeve ( incorporated in the removable component ) attachment , which provides a precision while seating and retention . in this case , the bar and clip attachment of andrews bridge system was replaced with magnets .
ni - plated , disc shaped , miniature ( 2 mm 1.5 mm ) , open field neodynium - iron - boron magnets were used . the magnetic attraction between the magnets
this modification makes the appliance economical still maintaining all the basic requirements of andrews bridge system such as facilitating good oral hygiene maintenance in addition to providing good functional and esthetic results .
moreover , these magnets do not exert any deleterious effects on the human tissues . the support in this system
is mainly derived from the abutment teeth so no pressure was applied to the tissues at the base of the defect which were devoid of any bone support .
the surfaces of magnets are exposed to oral fluids , which may lead to tarnish and corrosion .
this may produce disruption of the protective coating of the magnets leading to some cytotoxic effects .
it may result in the decreased retentive force upon usage . hence maintaining constant recalls and replacing the magnets as early as signs of corrosion develop may play a significant role in the durability and functioning of the appliance .
the surgical grafting procedures still remain the best treatment options for the cases with unesthetic ridge defects .
however , considering the treatment cost , invasiveness and treatment period in surgical procedures , the fixed removable system provides a rapid and economical substitute for achieving the desired treatment goals in cases with severe ridge defects . | ### Summary:
: prosthetic dentistry involves the replacement of missing and contiguous tissues with artificial substitutes to restore and maintain the oral functions , appearance , and health of the patient .
the treatment of edentulous areas with ridge defects poses a challenging task for the dentist .
management of such cases involves a wide range of treatment options comprising mainly of surgical interventions and non surgical techniques such as use of removable , fixed or fixed- removable partial dentures . but
each treatment plan undertaken should be customized according to patient needs . a variety of factors such as quality and quantity of existing contiguous hard and soft tissues , systemic condition and economic status of the patient play an important role in treatment planning , clinical outcome and prognosis .
this case report presents the restoration of a seibert 's class iii ridge defect by an economical modification of andrews bridge in a 32 year old patient . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
:
rupture of the long head of biceps ( lhb ) tendon most frequently occurs secondary to degenerative changes within the tendon and is associated with underlying rotator cuff tendinopathy.[13 ] a cadaveric study has shown concentration of degenerative changes within the tendon at the distal bicipital groove , which could explain the predilection for tendon rupture at that site .
less commonly , acute traumatic lhb ruptures may occur without the presence of rotator cuff disease and several cases have been reported in young athletes.[57 ] the vast majority of isolated lhb ruptures are asymptomatic , and thus are amenable to conservative management .
however , several clinical studies have demonstrated that elbow flexion strength could diminish by 8% to 16% , supination strength could decrease by 11% to 21% and muscle endurance could reduce by up to 25% , as a consequence of the ruptures.[911 ] these observations may explain the small group of patients who subsequently develop long - term cramping pain and discomfort associated with repetitive biceps activities . in these cases , biceps tenodesis may be considered to relieve the symptoms . in this article , we report the outcomes of patients who have undergone biceps tenodesis for symptomatic chronic lhb ruptures .
a retrospective review was performed of 11 consecutive patients ( 11 shoulders ) who underwent biceps tenodesis for symptomatic chronic lhb ruptures by the senior author between september 2006 and april 2011 .
the criteria used for inclusion in this study were any patients who had sustained isolated chronic ruptures of their lhb tendons and subsequently undergone biceps tenodesis at least 3 months after injury .
cases of biceps tenodesis performed for biceps tendonitis , instability or as part of other shoulder procedures were excluded from this study .
imaging such as ultrasound or mri was employed to exclude any underlying rotator cuff disease .
all patients had been seen by an orthopaedic surgeon within 3 months of lhb rupture .
all had failed to improve after a period of conservative treatment with analgesia and physiotherapy .
the primary complaint of the patients was cramping pain and discomfort associated with repetitive biceps use . the interval period between sustaining the injury to undergoing surgery was at least 6 months .
patient data were obtained from a prospectively managed database and telephone conversations with all the patients at the latest follow - up .
patient demographics included the following : age , gender , time to surgery after the injury , and length of follow - up .
findings at the time of surgery and tenodesis technique employed were also noted . at final follow - up ,
patient progress was evaluated with the following questions :
compared with before surgery , what is the percentage of improvement in the pain of your arm now ? ( 0 - 100%)compared with before surgery , what is the percentage of improvement in the strength of your arm now ?
( 0 - 100%)compared with your opposite ( normal ) arm , what is the strength of your operated arm now ?
( 0 - 100%)how long did it take for the operated arm to regain its maximal strength ?
( months)how would you grade the appearance of your biceps now?(0- no difference to before surgery;1- slightly better than before surgery;2- moderately better than before surgery;3- the same as before injury)are you glad to have had the surgery ? ( yes or no)all subjects gave informed consent to participate in the study .
approval by the local institutional review board was not required as it was considered a clinical audit .
compared with before surgery , what is the percentage of improvement in the pain of your arm now ?
( 0 - 100% ) compared with before surgery , what is the percentage of improvement in the strength of your arm now ?
( 0 - 100% ) compared with your opposite ( normal ) arm , what is the strength of your operated arm now ?
( 0 - 100% ) how long did it take for the operated arm to regain its maximal strength ? ( months ) how would you grade the appearance of your biceps now ?
( 0- no difference to before surgery ; 1- slightly better than before surgery ; 2- moderately better than before surgery ; 3- the same as before injury ) are you glad to have had the surgery ? ( yes or no ) all surgeries were performed or directly supervised by the senior author .
the patient was placed in the beach chair position with his / her arm on light traction holding the elbow in 30 degrees flexion and neutral forearm rotation .
a 3 cm longitudinal incision was made through the skin and subcutaneous tissue at the level of the proximal musculotendinous junction , where the defect in the upper arm was palpable .
the inferior edge of the pectoralis major was then identified and retracted superiorly to expose the humerus .
the tendon could then be reattached more proximally using an interference screw tenodesis technique . however , in some cases a decent tendon was not found due to the chronicity of the injury , degeneration of the tendon or site of injury being at the musculotendinous junction . in these cases
the retracted musculotendinous unit was mobilised as much as possible and an attachment point to the humerus was determined where it could be attached without undue tension with the elbow in 30 degrees flexion .
the insertion point on the humerus ( usually just distal to the inferior edge of the pectoralis major ) was prepared by decorticating a 2 2 cm area of the anterior humeral shaft , to allow endosteal bleeding .
three superquick ( depuy mitek ) anchors with double - loaded orthocord were then inserted in a triangular configuration .
the sutures were passed from deep to superficial through the torn end of the tendon , using a combination of mattress and modified kessler suture techniques .
the elbow and shoulder were then moved through full range to assess the tension of the repair .
for the first 3 weeks , the patient could actively mobilise the shoulder and elbow as tolerated .
however resisted elbow flexion and forced passive extension was avoided for 6 weeks after surgery .
the data were not normally distributed and hence , non - parametric test ( mann - whitney u test ) has been used to compare continuous variables between the study subgroups .
a pearson 's correlation coefficient was computed to assess the relationship between age at surgery and the interval between injury and surgery .
the patient was placed in the beach chair position with his / her arm on light traction holding the elbow in 30 degrees flexion and neutral forearm rotation .
a 3 cm longitudinal incision was made through the skin and subcutaneous tissue at the level of the proximal musculotendinous junction , where the defect in the upper arm was palpable .
the inferior edge of the pectoralis major was then identified and retracted superiorly to expose the humerus .
the tendon could then be reattached more proximally using an interference screw tenodesis technique . however , in some cases a decent tendon was not found due to the chronicity of the injury , degeneration of the tendon or site of injury being at the musculotendinous junction . in these cases
the retracted musculotendinous unit was mobilised as much as possible and an attachment point to the humerus was determined where it could be attached without undue tension with the elbow in 30 degrees flexion .
the insertion point on the humerus ( usually just distal to the inferior edge of the pectoralis major ) was prepared by decorticating a 2 2 cm area of the anterior humeral shaft , to allow endosteal bleeding .
three superquick ( depuy mitek ) anchors with double - loaded orthocord were then inserted in a triangular configuration .
the sutures were passed from deep to superficial through the torn end of the tendon , using a combination of mattress and modified kessler suture techniques .
the elbow and shoulder were then moved through full range to assess the tension of the repair .
following the operation , a sling was worn for comfort only . for the first 3 weeks , the patient could actively mobilise the shoulder and elbow as tolerated .
however resisted elbow flexion and forced passive extension was avoided for 6 weeks after surgery .
the data were not normally distributed and hence , non - parametric test ( mann - whitney u test ) has been used to compare continuous variables between the study subgroups .
a pearson 's correlation coefficient was computed to assess the relationship between age at surgery and the interval between injury and surgery .
the data were not normally distributed and hence , non - parametric test ( mann - whitney u test ) has been used to compare continuous variables between the study subgroups .
a pearson 's correlation coefficient was computed to assess the relationship between age at surgery and the interval between injury and surgery .
there were ten men and one woman with an average age at surgery of 41 years ( range 23 - 65 ) .
the mean interval between injury and surgery was 25 months ( range 6 - 96 ) .
the age at surgery and the interval between injury and surgery were correlated with r = 0.682 , p = 0.021 . in five of these cases ,
a decent quality tendon was found and tenodesis was performed using the in - bone interference screw technique .
however , in six cases , the tendon was not discernable or possible to tenodese with an in - bone interference screw .
furthermore , the biceps muscle was too retracted and irretrievable for a standard proximal biceps tenodesis . in these cases
we used a footprint on - bone tenodesis technique with suture anchors . the mean interval from injury to surgery of the suture anchor group ( 30.0 standard error of mean 13.9 months ) was longer than that of the interference screw group ( 18.0 3.6 months ) but the difference did not reach statistical significance ( mann - whitney u test , p = 0.927 ) . using a subjective pain scale ,
all except one patient reported improvement in their arm pain with a mean percentage of 78% ( 9 ) .
this refers to the percentage of relative improvement rather than an absolute reduction . using a subjective strength scale ,
all except one patient reported improvement in the strength of their arms with a mean percentage of 74% ( 9 ) . compared with their opposite arms ,
on average , patients took 11 months ( range 6 - 18 ) to reach the maximal recoverable strength of their arms .
all , except one , patients noted improvement in the appearance of their biceps contours .
three felt the appearance improved slightly after surgery ; four reported moderate degree of improvement ; and three felt that their biceps muscles now appeared the same as they were before the injury .
overall there was only one failure in this series who consistently reported no improvement in pain , strength and cosmesis .
he was the oldest patient ( 65 years ) in the series and had the longest interval between injury and surgery ( 96 months ) . there were no cases of infection , neurovascular injury , adhesive capsulitis or humeral fracture in the study population .
there were ten men and one woman with an average age at surgery of 41 years ( range 23 - 65 ) .
the mean interval between injury and surgery was 25 months ( range 6 - 96 ) .
the age at surgery and the interval between injury and surgery were correlated with r = 0.682 , p = 0.021 .
in five of these cases , a decent quality tendon was found and tenodesis was performed using the in - bone interference screw technique .
however , in six cases , the tendon was not discernable or possible to tenodese with an in - bone interference screw .
furthermore , the biceps muscle was too retracted and irretrievable for a standard proximal biceps tenodesis . in these cases
we used a footprint on - bone tenodesis technique with suture anchors . the mean interval from injury to surgery of the suture anchor group ( 30.0 standard error of mean 13.9 months ) was longer than that of the interference screw group ( 18.0 3.6 months ) but the difference did not reach statistical significance ( mann - whitney u test , p = 0.927 ) .
using a subjective pain scale , all except one patient reported improvement in their arm pain with a mean percentage of 78% ( 9 ) .
using a subjective strength scale , all except one patient reported improvement in the strength of their arms with a mean percentage of 74% ( 9 ) . compared with their opposite arms ,
, patients took 11 months ( range 6 - 18 ) to reach the maximal recoverable strength of their arms .
all , except one , patients noted improvement in the appearance of their biceps contours .
three felt the appearance improved slightly after surgery ; four reported moderate degree of improvement ; and three felt that their biceps muscles now appeared the same as they were before the injury .
overall there was only one failure in this series who consistently reported no improvement in pain , strength and cosmesis .
he was the oldest patient ( 65 years ) in the series and had the longest interval between injury and surgery ( 96 months ) .
there were no cases of infection , neurovascular injury , adhesive capsulitis or humeral fracture in the study population .
chronic rupture of the lhb tendon is usually asymptomatic , but some active patients suffer with long - term cramping pain and discomfort associated with repetitive biceps use .
we postulate that these are the patients that fail to auto - tenodese to the brachialis muscle , short head of biceps or humeral shaft .
a muscle requires two fixed points at both ends in order to contract and generate kinetic energy .
where the proximal fixation point is lost , contraction of the muscle leads to cramping and discomfort . in a specialist shoulder practice over a 4-year period , only 11 patients with the condition requested for surgery because of persistent troublesome symptoms . within the group
, younger patients appeared to tolerate discomfort less and tended to seek surgical intervention earlier .
in addition the patients were almost exclusively male , which may simply reflect higher physical demands of the patients .
there are many surgical techniques of proximal biceps tenodesis , including bone bridges , keyhole fixation , suture anchors , interference screw , or endobutton.[1217 ] the choice of a specific technique is dependent on the quality and mobility of the torn tendon end as well as skills and preference of the surgeon .
arthroscopic technique would not be suitable for this group of patients due to chronic retraction of the muscles .
when a good quality tendon that could be reattached more proximally in the humeral metaphysis was found , tenodesis using an interference screw was our preferred technique .
cadaveric studies have shown favourable biomechanical properties and load - to - failure of interference screw fixation . however in over half of the cases , the tendon quality was poor and degenerate .
in some it was completely absent precluding the use of an interference screw . in these cases ,
an in - situ tenodesis utilising three suture anchors at the humeral diaphysis was performed .
millett et al . , suggested that residual pain at the location of tenodesis could be an issue when suture anchors were used in the subpectoral location but this had not been our experience .
the use of interference screw at the humeral diaphysis is also not recommended due to the creation of stress riser at the drill hole and cases of delayed humeral fractures have been reported .
there is a paucity of literature specifically evaluating the outcomes of tenodesis for chronic lhb rupture .
tucker and dutta described a two - incision technique where the torn tendon was sutured using krakow technique which was then fixed to the bone with an interference screw .
they discussed briefly their clinical experience with three patients who were improved in terms of pain and appearance of their arms .
preoperatively , the patients were counselled specifically that the operation may not necessarily improve the appearance of their biceps contours .
rather the primary aim of the operation was to relieve the cramping pain associated with repetitive biceps activities .
nonetheless , all of the patients , except one , in this study noted some degree of improvement in the cosmesis of their biceps . in particular , three of the five patients who still retained a good quality tendon hence permitting reattachment of the tendon at a more proximal site reported that their biceps now appeared the same as before the injury .
the limitation of our study is that we had a relatively small sample size but this simply reflects the fact that most patients with isolated lhb ruptures respond well to conservative treatment .
symptomatic chronic lhb ruptures improve with a biceps tenodesis procedure . due to the chronicity of the injury and possible degeneration of the tendon , a suitable tendon for in - bone tenodesis using an interference screw may not always be found . in these cases | ### Summary:
: purpose : chronic rupture of the long head of biceps ( lhb ) tendon is usually asymptomatic .
however , some active patients suffer with long - term cramping pain associated with repetitive biceps use .
the aim of this study is to review the outcomes of biceps tenodesis performed for chronic lhb ruptures.materials and methods : we performed a retrospective review of 11 consecutive patients who underwent biceps tenodesis for symptomatic chronic lhb ruptures over a 4-year period.results:there were 10 men and one woman with an average age at surgery of 41 years ( range 23 - 65 ) .
the mean follow - up was 29 months ( range 6 - 60 ) . in five cases
a tendon was still identifiable and suitable for repair with an in - bone interference screw .
however , in six cases the tendon was not possible to tenodese with an interference screw .
in these cases we used an on - bone technique with suture anchors .
all , except one , patients reported improvement in their arm pain ( 78% ) , strength ( 74% ) and appearance .
all , except one , were glad to have had the surgery.conclusions:symptomatic chronic lhb ruptures improve with a biceps tenodesis procedure . due to the chronicity of the injury and possible degeneration of the tendon , a suitable tendon for in - bone tenodesis may not be possible . in these cases
an on - bone footprint repair with suture anchors achieves good results.level of evidence : iv ( retrospective case series ) . |
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: atrial fibrillation ( af ) is the most common cardiac arrhythmia and is expected to double till 2060 to 18 million in the eu when compared with 2010 .
many studies have investigated the efficacy of different drugs in converting af to sinus rhythm ( sr ) .
there are numerous randomized controlled trials comparing the value of these drugs with placebo , as well as among each other .
efficacy for acute conversion of af was demonstrated for ibutilide , flecainide , dofetilide , propafenone , and amiodarone , and there was moderate evidence for quinidine .
ibutilide , a class iii antiarrhythmic drug that blocks ikr , blocks the rapid component of the cardiac delayed rectifier potassium current and activates a late inward sodium current , is approved for acute termination of af and atrial flutter of recent onset and has been shown to be superior to sotalol and equivalent to flecainide in this indication in two randomized controlled trials .
recently , the relatively atrial selective antiarrhythmic agent vernakalant has been approved by the european medicines agency for the rapid conversion of recent - onset af to sr in adults .
it is recommended for rhythm control by the european society of cardiology ( esc ) since the 2010 guidelines and highlighted in a recent review .
vernakalant rapidly terminates af through blocking of potassium and frequency- and voltage - dependent sodium ion channels in all phases of the atrial action potential . in the avro trial ( a randomized active - controlled study comparing the efficacy and safety of vernakalant to amiodarone in recent - onset af ) ,
vernakalant demonstrated being more effective than amiodarone for acute conversion of recent - onset af as well as in a small single - centre trial from argentina , intravenous vernakalant was significantly faster in converting af to sr when compared with oral flecainide .
vernakalant and ibutilide have comparable pharmacokinetic properties and are both recommended by the current esc focused guidelines update for the management of af in patients with and without moderate , but not severe structural heart disease .
the aim of our study was to compare the time and the efficacy of conversion to sr within 90 min in patients with recent - onset af treated with vernakalant or ibutilide intravenously .
the study protocol was approved by the independent ethics committee of the medical university of vienna ( ek nr : 220/2011 ) .
the trial was conducted according to the ich - gcp guidelines ( international conference on harmonisation good clinical practice ) as well as the declaration of helsinki and registered at clinicaltrials.gov as nct01447862 ( eudract number 2011 - 000695 - 34 ) .
one hundred patients with recent - onset af ( symptoms of af since no longer than 48 h ) treated at the emergency department of the medical university of vienna have been enrolled in this block - randomized controlled trial .
prior to randomization we performed several routine baseline and screening examinations , which included medical history , physical exam , standard 12-lead ecg with measurement of qt interval , transthoracic echocardiography , chest x - ray , and routine laboratory testing ( including tsh and free t4 ) .
exclusion criteria were necessity for immediate electrical cardioversion due to haemodynamic instability ; heart failure nyha iii / iv ; a previously documented left ventricular ejection fraction of 35% ; history or signs of acute coronary syndrome within the last 30 days ; a resting ventricular rate of < 80 bpm without pacemaker backup ; a qt interval of > 440 ms ; presence of wolff parkinson white syndrome ; history of torsade de pointes ( tdp ) arrhythmia or other polymorphic ventricular tachycardias ( vts ) ; signs of thyrotoxicosis , sick sinus syndrome or atrioventricular block ii and iii , severe valvular heart disease , clinically meaningful hypertrophic obstructive cardiomyopathy , restrictive cardiomyopathy , or constrictive pericarditis ; serious disorders of the hepatic , renal , pulmonary , gastrointestinal , haematological , or central nervous system ; serious psychiatric disorders ; abnormal serum electrolytes despite adequate therapy ; intravenous use of any class i or iii antiarrhythmic drugs within 4 h prior to study drug application ; pregnancy ; and known hypersensitivity to study medications .
we did not include patients with atrial flutter as vernakalant treatment is not indicated in this patient group due to lack of efficacy .
block randomization into two treatment groups with variable block sizes of four to six was performed by an independent epidemiologist using www.randomization.com .
to conceal allocation we used sequentially numbered , sealed , opaque envelopes , which were produced before initiation of the study .
if potassium values were not in the high normal range ( > 4.2 mmol / l ) , patients received a pre - fabricated electrolyte infusion ( elozell spezial , 250 ml , fresenius kabi , austria ) with 24 mmol of potassium and 6 mmol of magnesium prior to randomization .
a total of 43 patients ( 88% ) in the vernakalant group and 38 patients ( 75% ) in the ibutilide group received this treatment .
additionally , according to local standard of care , most patients received 500 ml of a balanced electrolyte solution ( elo - mel isoton , fresenius kabi austria ) intravenously , in order to increase plasma volume .
all subjects were randomized to receive either up to two infusions of ibutilide ( 1 mg each in 100 ml normal saline ) intravenously over 10 min with an interruption of 10 min in - between or up to two infusions of vernakalant ( 3 and 2 mg / kg in 100 ml normal saline ) with an interruption of 15 min in - between .
subjects weighing < 60 kg received 0.01 mg / kg ibutilide according to the manufacturer 's instructions , as well as for subjects receiving vernakalant a maximum of 339 mg for the first , and 226 mg for the second infusion was not exceeded .
we further were interested if vernakalant pre - treatment may also enhances electrical cardioversion efficacy as shown for ibutilide .
therefore , according to the study protocol , consented study patients underwent electrical cardioversion if af persisted 2 h or longer after administration of first study drug dose .
we attempted a series of up to three electrical cardioversions ( biphasic defibrillation , philips heartstart mrx ) starting with 100 j and increasing energy up to 150 j and consequently 200 j ( figure 1 ) .
intravenous administration of ventricular rate controlling drugs ( -blockers , calcium channel blockers , digitalis ) was performed in both treatment groups if appropriate .
additionally , arterial blood pressure , qt , and qtc ( fridericia correction ) were measured every 20 min for the first 60 min ; additional measurements were performed after 120 , 240 min , and prior to discharge . to determine the exact time of conversion to sr , patients received continuous ecg monitoring .
treatment had to be discontinued according to the protocol if uncorrected qt interval increased to 550 ms or by > 25% from baseline , heart rate decreased to < 40 bpm , systolic blood pressure increased to > 190 mmhg or decreased to < 80 mmhg , new bundle - branch block developed or qrs interval increased by 50% from baseline , vt , recurrent non - sustained vt ( nsvt ; defined as three or more ventricular extrasystoles lasting < 30 s ) , a sinus pause of 5 s , complete heart block , or intolerable adverse effects occurred . a serious adverse event ( sae )
was defined according to the ich - gcp guidelines as an event resulting in death , a life - threatening condition , hospitalization or prolongation of existing hospitalization , or persistent or significant disability or incapacity .
patients were observed and monitored for at least 6 h after administration of first dosage of study drug .
time to sr measured from start of first study drug administration was the primary endpoint and conversion rate to sr within 90 min was defined as the secondary endpoint .
we described continuous variables using mean and standard deviation or median and quartiles , as appropriate .
for comparison of cardioversion success , we used survival analysis methods . cardioversion success until 90 min was analysed using the kaplan meier method with follow - up time starting at initiation of study medication and sustained sr defined as success ( 15 min at least ) . as electrical cardioversion time
was not protocol directed within the first 90 min , we censored follow - up for this analysis at 90 min .
we plotted 95% confidence intervals ( 95% ci ) around the survival probabilities and compared the intervention groups using a log - rank test .
as an additional analysis , we repeated this analysis without censoring using the follow - up time until the last success . to assess adverse effects and other categorized outcomes , we calculated absolute risk differences with exact 95% ci and used the fisher 's exact test for hypothesis testing . to assess other ancillary outcomes on a continuous scale
qt interval and blood pressure repeated measurements were available . to allow for the panel structure of these variables , we used multivariable random effects models with each of these measurements as outcome , intervention group , time , and treatment time interaction as covariates , and patient identifier as the cluster identifier to estimate the difference between the intervention groups based on a wald test . a two - sided p - value of < 0.05 was considered statistically significant .
all analyses were performed using ms excel 2011 and stata 11 ( statacorp , college station , tx , usa ) for mac .
we were planning a study with one control per experimental subject , with a follow - up time of 90 min after initial treatment .
prior data indicated that the median time to conversion in the control treatment was 25 min .
if the true median time to conversion in the control and experimental treatments was 25 and 12 min , respectively , we needed to study 30 experimental subjects and 30 control subjects to be able to reject the null hypothesis that the experimental and control survival curves ( based on time to conversion ) are equal with a power of 80% .
the type i error probability associated with this log - rank test of this null hypothesis is 0.05 . to compensate for an expectedly large number of missing data , we increased the study sample to 50 patients per group .
one hundred patients with recent - onset af ( symptoms of af since no longer than 48 h ) treated at the emergency department of the medical university of vienna have been enrolled in this block - randomized controlled trial .
prior to randomization we performed several routine baseline and screening examinations , which included medical history , physical exam , standard 12-lead ecg with measurement of qt interval , transthoracic echocardiography , chest x - ray , and routine laboratory testing ( including tsh and free t4 ) .
exclusion criteria were necessity for immediate electrical cardioversion due to haemodynamic instability ; heart failure nyha iii / iv ; a previously documented left ventricular ejection fraction of 35% ; history or signs of acute coronary syndrome within the last 30 days ; a resting ventricular rate of < 80 bpm without pacemaker backup ; a qt interval of > 440 ms ; presence of wolff parkinson white syndrome ; history of torsade de pointes ( tdp ) arrhythmia or other polymorphic ventricular tachycardias ( vts ) ; signs of thyrotoxicosis , sick sinus syndrome or atrioventricular block ii and iii , severe valvular heart disease , clinically meaningful hypertrophic obstructive cardiomyopathy , restrictive cardiomyopathy , or constrictive pericarditis ; serious disorders of the hepatic , renal , pulmonary , gastrointestinal , haematological , or central nervous system ; serious psychiatric disorders ; abnormal serum electrolytes despite adequate therapy ; intravenous use of any class i or iii antiarrhythmic drugs within 4 h prior to study drug application ; pregnancy ; and known hypersensitivity to study medications .
we did not include patients with atrial flutter as vernakalant treatment is not indicated in this patient group due to lack of efficacy .
block randomization into two treatment groups with variable block sizes of four to six was performed by an independent epidemiologist using www.randomization.com . to conceal allocation we used sequentially numbered , sealed , opaque envelopes , which were produced before initiation of the study .
if potassium values were not in the high normal range ( > 4.2 mmol / l ) , patients received a pre - fabricated electrolyte infusion ( elozell spezial , 250 ml , fresenius kabi , austria ) with 24 mmol of potassium and 6 mmol of magnesium prior to randomization .
a total of 43 patients ( 88% ) in the vernakalant group and 38 patients ( 75% ) in the ibutilide group received this treatment .
additionally , according to local standard of care , most patients received 500 ml of a balanced electrolyte solution ( elo - mel isoton , fresenius kabi austria ) intravenously , in order to increase plasma volume .
all subjects were randomized to receive either up to two infusions of ibutilide ( 1 mg each in 100 ml normal saline ) intravenously over 10 min with an interruption of 10 min in - between or up to two infusions of vernakalant ( 3 and 2 mg / kg in 100 ml normal saline ) with an interruption of 15 min in - between .
subjects weighing < 60 kg received 0.01 mg / kg ibutilide according to the manufacturer 's instructions , as well as for subjects receiving vernakalant a maximum of 339 mg for the first , and 226 mg for the second infusion was not exceeded .
we further were interested if vernakalant pre - treatment may also enhances electrical cardioversion efficacy as shown for ibutilide .
therefore , according to the study protocol , consented study patients underwent electrical cardioversion if af persisted 2 h or longer after administration of first study drug dose .
we attempted a series of up to three electrical cardioversions ( biphasic defibrillation , philips heartstart mrx ) starting with 100 j and increasing energy up to 150 j and consequently 200 j ( figure 1 ) .
intravenous administration of ventricular rate controlling drugs ( -blockers , calcium channel blockers , digitalis ) was performed in both treatment groups if appropriate .
additionally , arterial blood pressure , qt , and qtc ( fridericia correction ) were measured every 20 min for the first 60 min ; additional measurements were performed after 120 , 240 min , and prior to discharge .
to determine the exact time of conversion to sr , patients received continuous ecg monitoring .
treatment had to be discontinued according to the protocol if uncorrected qt interval increased to 550 ms or by > 25% from baseline , heart rate decreased to < 40 bpm , systolic blood pressure increased to > 190 mmhg or decreased to < 80 mmhg , new bundle - branch block developed or qrs interval increased by 50% from baseline , vt , recurrent non - sustained vt ( nsvt ; defined as three or more ventricular extrasystoles lasting < 30 s ) , a sinus pause of 5 s , complete heart block , or intolerable adverse effects occurred . a serious adverse event ( sae )
was defined according to the ich - gcp guidelines as an event resulting in death , a life - threatening condition , hospitalization or prolongation of existing hospitalization , or persistent or significant disability or incapacity .
patients were observed and monitored for at least 6 h after administration of first dosage of study drug .
time to sr measured from start of first study drug administration was the primary endpoint and conversion rate to sr within 90 min was defined as the secondary endpoint .
time to sr measured from start of first study drug administration was the primary endpoint and conversion rate to sr within 90 min was defined as the secondary endpoint .
we described continuous variables using mean and standard deviation or median and quartiles , as appropriate .
for comparison of cardioversion success , we used survival analysis methods . cardioversion success until 90 min was analysed using the kaplan meier method with follow - up time starting at initiation of study medication and sustained sr defined as success ( 15 min at least ) . as electrical cardioversion time
was not protocol directed within the first 90 min , we censored follow - up for this analysis at 90 min .
we plotted 95% confidence intervals ( 95% ci ) around the survival probabilities and compared the intervention groups using a log - rank test .
as an additional analysis , we repeated this analysis without censoring using the follow - up time until the last success . to assess adverse effects and other categorized outcomes , we calculated absolute risk differences with exact 95% ci and used the fisher 's exact test for hypothesis testing . to assess other ancillary outcomes on a continuous scale
qt interval and blood pressure repeated measurements were available . to allow for the panel structure of these variables
, we used multivariable random effects models with each of these measurements as outcome , intervention group , time , and treatment time interaction as covariates , and patient identifier as the cluster identifier to estimate the difference between the intervention groups based on a wald test .
all analyses were performed using ms excel 2011 and stata 11 ( statacorp , college station , tx , usa ) for mac .
we were planning a study with one control per experimental subject , with a follow - up time of 90 min after initial treatment .
prior data indicated that the median time to conversion in the control treatment was 25 min .
if the true median time to conversion in the control and experimental treatments was 25 and 12 min , respectively , we needed to study 30 experimental subjects and 30 control subjects to be able to reject the null hypothesis that the experimental and control survival curves ( based on time to conversion ) are equal with a power of 80% .
the type i error probability associated with this log - rank test of this null hypothesis is 0.05 . to compensate for an expectedly large number of missing data
from january 2012 to march 2015 , a total of 209 patients were screened for eligibility , of which 101 patients were enrolled in this single - centre randomized controlled trial .
a total of 108 patients were excluded , whereof 53 patients did not meet the inclusion criteria , 28 declined to participate , and 27 patients converted to sr during screening phase .
the two treatment groups were well balanced ; there were no significant differences regarding demographics and baseline characteristics ( table 1 ) .
however , more patients in the ibutilide group had previous ablation ( 7 vs. 2 ) .
this did not affect conversion rate in our study and did not significantly affect further analyses .
interestingly , although af was recurrent in a large proportion of patients , use of prophylactic oral antiarrhythmic drug therapy was low in both study groups .
table 1demographics and baseline characteristicstreatment grouptotal ( n = 100)p - valuevernakalant ( n = 49)ibutilide ( n = 51)baseline characteristics male , n ( % ) 34 ( 69.4)34 ( 66.7)680.832 age ( year ) , mean ( sd)56.2 ( 14.32)56.7 ( 15.77)56.5 ( 15.00)0.873 weight ( kg ) , mean ( sd)87.6 ( 16.57)87.0 ( 15.21)87.3 ( 15.81)0.847 no previous episode of af , n ( % ) 21 ( 42.9)15 ( 29.4)360.212 15 previous episodes of af , n ( % ) 15 ( 30.6)22 ( 43.1)370.211 610 previous episodes of af , n ( % ) 7 ( 14.3)7 ( 14.3)141.000 > 10 previous episodes of af , n ( % ) 5 ( 10.2)5 ( 10.2)101.000 history of at least one previous pharmacological cardioversion , n ( % ) 12 ( 24.5)21 ( 41.2)330.091 history of at least one previous electrical cardioversion , n ( % ) 15 ( 30.6)17 ( 33.3)320.832 paroxysmal af , n ( % ) 8 ( 16.3)6 ( 11.8)140.573 persistent af , n ( % ) 20 ( 40.8)30 ( 58.8)500.109 median duration of current af ( h ) , mean ( sd)10.9 ( 9.9)8.7 ( 6.2)9.7 ( 8.25)0.797 af duration 24 h , n ( % ) 43 ( 87.8)50 ( 98.0)930.057medical history , n ( % ) hypertension30 ( 61.2)36 ( 70.6)660.400 diabetes5 ( 10.2)6 ( 11.8)111.000 dyslipidaemia24 ( 49)21 ( 41.2)450.547 smoking or previous smoking17 ( 34.7)18 ( 35.3)350.791 hypothyreosis6 ( 12.2)6 ( 11.8)110.760 hyperthyreosis1 ( 2.0)1 ( 2.0)21.000 previous ablation / pvi2 ( 4.1)7 ( 13.7)90.160 coronary heart disease3 ( 6.1)4 ( 7.8)71.000scores , n ( % ) nyha i42 ( 85.7)49 ( 96.1)910.105 nyha ii6 ( 12.2)2 ( 3.9)80.160 ehra 238 ( 77.6)40 ( 78.4)781.000 ehra > 211 ( 22.4)11 ( 21.6)221.000 cha2ds2vasc ( mean , iqr)1.7 ( 12)1.8 ( 13)1.8 ( 12)0.665regular oral medication , n ( % ) -blockers23 ( 46.9)29 ( 56.9)520.423 digitalis glycosides2 ( 4.1)1 ( 2.0)30.614 amiodarone4 ( 8.2)1 ( 2.0)50.200 sotalol1 ( 2.0)3 ( 5.9)40.618 ace inhibitors or arbs26 ( 53.1)29 ( 56.9)550.841 thyroid hormone substitution6 ( 12.2)6 ( 11.8)121.000values are patients , n ( % ) . -blockers : oral non - selective and selective -blockers ( excluding sotalol ) and - and -blocking agents ( e.g. carvedilol ) ; digitalis glycosides : digoxin and digitoxin.af , atrial fibrillation ; ace , angiotensin - converting enzyme ; arbs , angiotensin ii receptor blockers ; ehra , european heart rhythm association ; iqr , interquartile range ; nyha , new york heart association ; pvi , pulmonary vein isolation ; sd , standard deviation .
-blockers : oral non - selective and selective -blockers ( excluding sotalol ) and - and -blocking agents ( e.g. carvedilol ) ; digitalis glycosides : digoxin and digitoxin .
af , atrial fibrillation ; ace , angiotensin - converting enzyme ; arbs , angiotensin ii receptor blockers ; ehra , european heart rhythm association ; iqr , interquartile range ; nyha , new york heart association ; pvi , pulmonary vein isolation ; sd , standard deviation . from 101 randomized patients , 100 ( 49 in the vernakalant group and 51 in the ibutilide group ) received at least one dose of study drug and were included in further analyses ( figure 2 ) .
one patient in the ibutilide group received one study drug infusion only because of recurrent nsvt .
another patient in this group weighing 48 kg received weight - adjusted reduced dose according to manufacturer 's instructions .
one patient within the ibutilide group did not receive second study drug due to occurrence of recurrent nsvt .
one patient within the ibutilide group did not receive second study drug due to occurrence of recurrent nsvt .
another patient was erroneously randomized despite the then unknown presence of an exclusion criteria ( severe aortic stenosis ) .
subsequently , no study drug was administered , no further data acquisition or analysis was performed , and the patient was excluded with replacement . the primary study endpoint
time to conversion of af to sr was significantly shorter in the vernakalant group when compared with the ibutilide group [ median time : 10 ( iqr = 617 ) vs. 26 ( iqr = 955 ) minutes , p = 0.01 ] .
conversion success within 90 min was achieved significantly more frequent in the vernakalant group with 34 patients when compared with 22 patients in the ibutilide group ( 69 vs. 43% , log - rank p = 0.002 , figure 3 ) . consistently , 29 patients ( 59% ) in the vernakalant group when compared with 14 patients ( 27% ) in the ibutilide group [ absolute risk reduction 32% ( 95% ci 1350% ) , p = 0.002 ] converted into sr prior to administration of second infusion of study drug .
x - axis : time from start of first infusion ( minutes ) ; y - axis : proportion of patients with conversion to sinus rhythm ( 95% ci ) .
x - axis : time from start of first infusion ( minutes ) ; y - axis : proportion of patients with conversion to sinus rhythm ( 95% ci ) .
late pharmacological conversion ( achieving sr 120240 min after study drug administration ) was observed in five patients ( two in the vernakalant group and three in the ibutilide group ) .
there was no relapse of af after successful pharmacological cardioversion in any of the patients in both groups during the observation period of 6 h. a total of 39 patients ( 13 in the vernakalant group and 26 in the ibutilide group ) did not convert to sr within 2 h or more after start of first study drug administration .
of the 13 patients , 12 ( 92% ) in the vernakalant group underwent successful electrical cardioversion with one shock , whereas only 17 of 26 patients ( 65% ) in the ibutilide group converted to sr after application of one shock .
three patients in the ibutilide group and one patient in the vernakalant group did not convert to sr after a series of three shocks ( 100j , 150j , 200j ) .
no sae was observed within the two treatment groups ( table 2 ) .
table 2summary of adverse events occurring during observational periodtreatment grouprisk difference ( 95% ci)p - valuevernakalant ( n = 49)n ( % ) ibutilide ( n = 51)n ( % ) any treatment - emergent ae13 ( 26.5)18 ( 35.3)0.09% ( 0.09 to 0.27)0.392common treatment - emergent aes pvc0 ( 0.0)8 ( 15.7)0.16% ( 26 to 05)0.004 non - sustained vt0 ( 0.0)7 ( 13.7)0.14% ( 23 to 04)0.007 aberrant conduction0 ( 0.0)7 ( 13.7)0.14% ( 23 to 04)0.007 sneezing6 ( 12.2)0 ( 0.0)0.12% ( 21 to 03)0.011 atrial flutter4 ( 8.2)0 ( 0.0)0.08% ( 16 to 00)0.054 paresthesia4 ( 8.2)0 ( 0.0)0.08% ( 16 to 00)0.054 dysgeusia3 ( 6.1)0 ( 0.0)0.06% ( 13 to 01)0.113 dry mouth1 ( 2.0)2 ( 3.9)0.02% ( 05 to 09)1.000 bradycardia2 ( 4.1)1 ( 2.0)0.02% ( 09 to 05)0.613 sves1 ( 2.0)1 ( 2.0)0.00% ( 06 to 05)1.000discontinuations due to aes0 ( 0.0)1 ( 2.0)0.02% ( 02 to 06)1.000any treatment - emergent sae0 ( 0.0)0 ( 0.0)values are patients , n ( % ) .ae , adverse event ; pvc , premature ventricular complex ; sae , serious adverse event ; sves , supraventricular extrasystole ; vt , ventricular tachycardia.treatment-emergent aes were defined as any ae that began or worsened following the start of study drug infusion.common treatment - emergent aes were those that occurred in 2 patients in the study . summary of adverse events occurring during observational
ae , adverse event ; pvc , premature ventricular complex ; sae , serious adverse event ; sves , supraventricular extrasystole ; vt , ventricular tachycardia .
treatment - emergent aes were defined as any ae that began or worsened following the start of study drug infusion .
common treatment - emergent aes were those that occurred in 2 patients in the study .
there were no cases of tdp , ventricular fibrillation , or polymorphic or sustained vt in either group .
premature ventricular contraction ( pvc ) , nsvt , and aberrant conduction were observed only in the ibutilide group ( 8 vs. 0 , 7 vs. 0 , and 7 vs. 0 ) .
however , one patient did not receive the second study drug infusion due to recurrent nsvts after the first infusion .
further treatment was not mandatory , and the patient underwent successful electrical cardioversion in order to restore sr .
occurrence of atrial flutter ( afl ) after study drug administration was observed in none of the patients in the ibutilide group and in four patients in the vernakalant group ( 8.2% ) .
three of them converted successfully to sr within 90 min after study drug administration , and one underwent electrical cardioversion in order to achieve sr .
no atrial flutter events were considered to be serious , and no patient developed 1:1 atrioventricular conduction during the episodes .
minor adverse events like sneezing ( 12.2% ) , paraesthesia ( 8.2% ) , and dysgeusia ( 6.1% ) occurred in the vernakalant group only .
likewise , systolic and diastolic blood pressure decreased within both groups ( figure 4 ) ; however , in patients receiving vernakalant , a slight initial increase in diastolic blood pressure occurred within the first 2040 min after application of first study drug dose . in both groups , qtcf increased , however , significantly more pronounced in the ibutilide group ( figure 5 ) .
figure 4heart rate ( a ) and blood pressure ( b ) over 6 h after administration of first study drug infusion .
absolute values and mean change from baseline within 360 min after administration of first study drug infusion .
figure 5mean qt interval ( a ) and qtcf interval ( b ) over 6 h after administration of first study drug infusion .
absolute values and mean change from baseline within 360 min after administration of first study drug infusion .
heart rate ( a ) and blood pressure ( b ) over 6 h after administration of first study drug infusion .
absolute values and mean change from baseline within 360 min after administration of first study drug infusion .
mean qt interval ( a ) and qtcf interval ( b ) over 6 h after administration of first study drug infusion .
absolute values and mean change from baseline within 360 min after administration of first study drug infusion .
from january 2012 to march 2015 , a total of 209 patients were screened for eligibility , of which 101 patients were enrolled in this single - centre randomized controlled trial .
a total of 108 patients were excluded , whereof 53 patients did not meet the inclusion criteria , 28 declined to participate , and 27 patients converted to sr during screening phase .
the two treatment groups were well balanced ; there were no significant differences regarding demographics and baseline characteristics ( table 1 ) .
however , more patients in the ibutilide group had previous ablation ( 7 vs. 2 ) .
this did not affect conversion rate in our study and did not significantly affect further analyses .
interestingly , although af was recurrent in a large proportion of patients , use of prophylactic oral antiarrhythmic drug therapy was low in both study groups .
table 1demographics and baseline characteristicstreatment grouptotal ( n = 100)p - valuevernakalant ( n = 49)ibutilide ( n = 51)baseline characteristics male , n ( % ) 34 ( 69.4)34 ( 66.7)680.832 age ( year ) , mean ( sd)56.2 ( 14.32)56.7 ( 15.77)56.5 ( 15.00)0.873 weight ( kg ) , mean ( sd)87.6 ( 16.57)87.0 ( 15.21)87.3 ( 15.81)0.847 no previous episode of af , n ( % ) 21 ( 42.9)15 ( 29.4)360.212 15 previous episodes of af , n ( % ) 15 ( 30.6)22 ( 43.1)370.211 610 previous episodes of af , n ( % ) 7 ( 14.3)7 ( 14.3)141.000 > 10 previous episodes of af , n ( % ) 5 ( 10.2)5 ( 10.2)101.000 history of at least one previous pharmacological cardioversion , n ( % ) 12 ( 24.5)21 ( 41.2)330.091 history of at least one previous electrical cardioversion , n ( % ) 15 ( 30.6)17 ( 33.3)320.832 paroxysmal af , n ( % ) 8 ( 16.3)6 ( 11.8)140.573 persistent af , n ( % ) 20 ( 40.8)30 ( 58.8)500.109 median duration of current af ( h ) , mean ( sd)10.9 ( 9.9)8.7 ( 6.2)9.7 ( 8.25)0.797 af duration 24 h , n ( % ) 43 ( 87.8)50 ( 98.0)930.057medical history , n ( % ) hypertension30 ( 61.2)36 ( 70.6)660.400 diabetes5 ( 10.2)6 ( 11.8)111.000 dyslipidaemia24 ( 49)21 ( 41.2)450.547 smoking or previous smoking17 ( 34.7)18 ( 35.3)350.791 hypothyreosis6 ( 12.2)6 ( 11.8)110.760 hyperthyreosis1 ( 2.0)1 ( 2.0)21.000 previous ablation / pvi2 ( 4.1)7 ( 13.7)90.160 coronary heart disease3 ( 6.1)4 ( 7.8)71.000scores , n ( % ) nyha i42 ( 85.7)49 ( 96.1)910.105 nyha ii6 ( 12.2)2 ( 3.9)80.160 ehra 238 ( 77.6)40 ( 78.4)781.000 ehra > 211 ( 22.4)11 ( 21.6)221.000 cha2ds2vasc ( mean , iqr)1.7 ( 12)1.8 ( 13)1.8 ( 12)0.665regular oral medication , n ( % ) -blockers23 ( 46.9)29 ( 56.9)520.423 digitalis glycosides2 ( 4.1)1 ( 2.0)30.614 amiodarone4 ( 8.2)1 ( 2.0)50.200 sotalol1 ( 2.0)3 ( 5.9)40.618 ace inhibitors or arbs26 ( 53.1)29 ( 56.9)550.841 thyroid hormone substitution6 ( 12.2)6 ( 11.8)121.000values are patients , n ( % ) . -blockers : oral non - selective and selective -blockers ( excluding sotalol ) and - and -blocking agents ( e.g. carvedilol ) ; digitalis glycosides : digoxin and digitoxin.af , atrial fibrillation ; ace , angiotensin - converting enzyme ; arbs , angiotensin ii receptor blockers ; ehra , european heart rhythm association ; iqr , interquartile range ; nyha , new york heart association ; pvi , pulmonary vein isolation ; sd , standard deviation .
-blockers : oral non - selective and selective -blockers ( excluding sotalol ) and - and -blocking agents ( e.g. carvedilol ) ; digitalis glycosides : digoxin and digitoxin .
af , atrial fibrillation ; ace , angiotensin - converting enzyme ; arbs , angiotensin ii receptor blockers ; ehra , european heart rhythm association ; iqr , interquartile range ; nyha , new york heart association ; pvi , pulmonary vein isolation ; sd , standard deviation . from 101 randomized patients , 100 ( 49 in the vernakalant group and 51 in the ibutilide group ) received at least one dose of study drug and were included in further analyses ( figure 2 ) .
one patient in the ibutilide group received one study drug infusion only because of recurrent nsvt .
another patient in this group weighing 48 kg received weight - adjusted reduced dose according to manufacturer 's instructions .
one patient within the ibutilide group did not receive second study drug due to occurrence of recurrent nsvt .
one patient within the ibutilide group did not receive second study drug due to occurrence of recurrent nsvt .
another patient was erroneously randomized despite the then unknown presence of an exclusion criteria ( severe aortic stenosis ) .
subsequently , no study drug was administered , no further data acquisition or analysis was performed , and the patient was excluded with replacement .
the primary study endpoint time to conversion of af to sr was significantly shorter in the vernakalant group when compared with the ibutilide group [ median time : 10 ( iqr = 617 ) vs. 26 ( iqr = 955 ) minutes , p = 0.01 ] . likewise , the secondary endpoint
conversion success within 90 min was achieved significantly more frequent in the vernakalant group with 34 patients when compared with 22 patients in the ibutilide group ( 69 vs. 43% , log - rank p = 0.002 , figure 3 ) . consistently , 29 patients ( 59% ) in the vernakalant group when compared with 14 patients ( 27% ) in the ibutilide group [ absolute risk reduction 32% ( 95% ci 1350% ) , p = 0.002 ] converted into sr prior to administration of second infusion of study drug .
x - axis : time from start of first infusion ( minutes ) ; y - axis : proportion of patients with conversion to sinus rhythm ( 95% ci ) .
x - axis : time from start of first infusion ( minutes ) ; y - axis : proportion of patients with conversion to sinus rhythm ( 95% ci ) .
late pharmacological conversion ( achieving sr 120240 min after study drug administration ) was observed in five patients ( two in the vernakalant group and three in the ibutilide group ) .
there was no relapse of af after successful pharmacological cardioversion in any of the patients in both groups during the observation period of 6 h. a total of 39 patients ( 13 in the vernakalant group and 26 in the ibutilide group ) did not convert to sr within 2 h or more after start of first study drug administration .
of the 13 patients , 12 ( 92% ) in the vernakalant group underwent successful electrical cardioversion with one shock , whereas only 17 of 26 patients ( 65% ) in the ibutilide group converted to sr after application of one shock .
three patients in the ibutilide group and one patient in the vernakalant group did not convert to sr after a series of three shocks ( 100j , 150j , 200j ) .
no sae was observed within the two treatment groups ( table 2 ) .
table 2summary of adverse events occurring during observational periodtreatment grouprisk difference ( 95% ci)p - valuevernakalant ( n = 49)n ( % ) ibutilide ( n = 51)n ( % ) any treatment - emergent ae13 ( 26.5)18 ( 35.3)0.09% ( 0.09 to 0.27)0.392common treatment - emergent aes pvc0 ( 0.0)8 ( 15.7)0.16% ( 26 to 05)0.004 non - sustained vt0 ( 0.0)7 ( 13.7)0.14% ( 23 to 04)0.007 aberrant conduction0 ( 0.0)7 ( 13.7)0.14% ( 23 to 04)0.007 sneezing6 ( 12.2)0 ( 0.0)0.12% ( 21 to 03)0.011 atrial flutter4 ( 8.2)0 ( 0.0)0.08% ( 16 to 00)0.054 paresthesia4 ( 8.2)0 ( 0.0)0.08% ( 16 to 00)0.054 dysgeusia3 ( 6.1)0 ( 0.0)0.06% ( 13 to 01)0.113 dry mouth1 ( 2.0)2 ( 3.9)0.02% ( 05 to 09)1.000 bradycardia2 ( 4.1)1 ( 2.0)0.02% ( 09 to 05)0.613 sves1 ( 2.0)1 ( 2.0)0.00% ( 06 to 05)1.000discontinuations due to aes0 ( 0.0)1 ( 2.0)0.02% ( 02 to 06)1.000any treatment - emergent sae0 ( 0.0)0 ( 0.0)values are patients , n ( % ) .ae , adverse event ; pvc , premature ventricular complex ; sae , serious adverse event ; sves , supraventricular extrasystole ; vt , ventricular tachycardia.treatment-emergent aes were defined as any ae that began or worsened following the start of study drug infusion.common treatment - emergent aes were those that occurred in 2 patients in the study .
summary of adverse events occurring during observational period values are patients , n ( % ) .
ae , adverse event ; pvc , premature ventricular complex ; sae , serious adverse event ; sves , supraventricular extrasystole ; vt , ventricular tachycardia .
treatment - emergent aes were defined as any ae that began or worsened following the start of study drug infusion .
common treatment - emergent aes were those that occurred in 2 patients in the study .
there were no cases of tdp , ventricular fibrillation , or polymorphic or sustained vt in either group .
premature ventricular contraction ( pvc ) , nsvt , and aberrant conduction were observed only in the ibutilide group ( 8 vs. 0 , 7 vs. 0 , and 7 vs. 0 ) .
however , one patient did not receive the second study drug infusion due to recurrent nsvts after the first infusion .
further treatment was not mandatory , and the patient underwent successful electrical cardioversion in order to restore sr .
occurrence of atrial flutter ( afl ) after study drug administration was observed in none of the patients in the ibutilide group and in four patients in the vernakalant group ( 8.2% ) .
three of them converted successfully to sr within 90 min after study drug administration , and one underwent electrical cardioversion in order to achieve sr .
no atrial flutter events were considered to be serious , and no patient developed 1:1 atrioventricular conduction during the episodes .
minor adverse events like sneezing ( 12.2% ) , paraesthesia ( 8.2% ) , and dysgeusia ( 6.1% ) occurred in the vernakalant group only .
likewise , systolic and diastolic blood pressure decreased within both groups ( figure 4 ) ; however , in patients receiving vernakalant , a slight initial increase in diastolic blood pressure occurred within the first 2040 min after application of first study drug dose . in both groups ,
qtcf increased , however , significantly more pronounced in the ibutilide group ( figure 5 ) .
figure 4heart rate ( a ) and blood pressure ( b ) over 6 h after administration of first study drug infusion . absolute values and mean change from baseline within 360 min after administration of first study drug infusion .
figure 5mean qt interval ( a ) and qtcf interval ( b ) over 6 h after administration of first study drug infusion .
absolute values and mean change from baseline within 360 min after administration of first study drug infusion .
. heart rate ( a ) and blood pressure ( b ) over 6 h after administration of first study drug infusion .
absolute values and mean change from baseline within 360 min after administration of first study drug infusion .
mean qt interval ( a ) and qtcf interval ( b ) over 6 h after administration of first study drug infusion .
absolute values and mean change from baseline within 360 min after administration of first study drug infusion .
this is , to our knowledge , the first study that compared the efficacy and safety of vernakalant and ibutilide , two anti - arrhythmic drugs with similar pharmacokinetic properties and clinical indications according to the current esc focused guidelines update for the management of af .
the study has demonstrated that vernakalant is significantly faster and more effective than ibutilide for achieving sr in recent - onset af in the emergency department setting .
the rapid time to conversion in vernakalant - treated patients is consistent with phase iii studies of intravenous vernakalant including the avro trial and a recent single - centre study , which compared intravenous vernakalant to oral flecainide .
the efficacy of vernakalant in converting recent - onset af was even higher in our study than previously reported in several trials .
the majority of those studies observed conversion rates of 50% , with an increased conversion success of 60% in one post hoc analysis .
in one recent swedish cohort study including 251 patients , a conversion rate of 70% was reported , which is comparable to our findings .
just two small single - centre studies from argentina , each with 17 patients receiving vernakalant , reported even higher conversion rates of 76.4% within 30 min and 93% within 2 h. the high conversion rate in our study might be related with the low number of patients with greater co - morbidities ( e.g. structural heart disease ) , the rather young patient age and the relatively short duration of af prior to study inclusion .
the conversion rate in the ibutilide group was in the same range as in previous trials that compared the efficacy of ibutilide with placebo or other antiarrhythmic agents .
conversion rates of 3551% have been observed in those studies , with the highest efficacy in patients with atrial flutter and in patients with af lasting < 48 h. likewise , the time to conversion is comparable to our results ( mean conversion time of 2733 min ) .
the electrophysiological actions of the mixed ion channel blocker vernakalant are largely characterized by frequency - dependent alterations of peak sodium channel currents including effective refractory period prolongation due to induction of post - repolarization refractoriness . additionally , vernakalant acts by blockade of the ultra - rapid delayed potassium atrial rectifier current ( ikur ) , with consequent prolongation of the atrial effective refractory period .
these effects may explain the prominent anti - af efficacy and consequently the superiority when compared with ibutilide , which acts by blocking the rapid component of the cardiac delayed rectifier potassium and by activation of a late inward sodium current .
the benefits of an early cardioversion and a comprehensive rhythm control therapy include a reduction in the risk of recurrent af episodes , less need for electrical cardioversion , prevention of prolonged and expensive hospital admissions , and might improve overall outcome , a question addressed in the on - going east ( early treatment of atrial fibrillation for stroke prevention trial ) study .
indeed , significantly less patients in the vernakalant group needed electrical cardioversion ( 13 when compared with 26 patients in the ibutilide group ) , and duration of emergency department stay could have been significantly shortened , especially in the vernakalant group , if an observational period of at least 6 h would not have been required by our study protocol .
accordingly , the cumulative time to conversion to sr , summarizing pharmacological and electrical cardioversion , was shorter in the vernakalant group when compared with the ibutilide group [ median time : 15 ( iqr = 8140 ) vs. 124 ( iqr = 20241 ) ] . of interest , vernakalant was at least as effective as ibutilide in enhancing electrical cardioversion . of 13 patients , 12 ( 92% ) in the vernakalant group
were successfully electrically cardioverted with one shock of 100 j , when compared with only 17 of 26 patients ( 65% ) in the ibutilide group .
this finding is in line with a recently published study from germany in which vernakalant was more effective than amiodarone in facilitating electrical cardioversion in patients with either immediate af recurrence or failed electrical cardioversion after antiarrhythmic - nave electrical cardioversion .
both study drugs were well tolerated in our study , and most observed adverse events were in the range of previous trials .
dysgeusia , sneezing , and paraesthesia were comparable to the summarized findings from the phase ii and phase iii trials of intravenous vernakalant vs. placebo ( dysgeusia 20.4% , sneezing 15% , paraesthesia 8.8% ) and the avro trial ( dysgeusia 6.9% , sneezing 3.4% ) .
likewise , atrial flutter occurred with the same incidence as in the avro trial ( 8.2 vs. 8.6% ) .
non - sustained vts occurred in 14% ( n = 7 ) of the patients in the ibutilide group .
this incidence is higher as reported in previous studies with ibutilide , where nsvts were observed in 4.98.3% of treated patients .
in line with previous reports , qt and qtc prolongation was particularly pronounced in the ibutilide group . of interest ,
no patient experienced relevant arterial hypotension , and blood pressure did not differ between treatment groups , although hypotension is a potential dangerous adverse event developing after vernakalant administration in 6% of patients . this might be at least partly attributable to our local standard of care intravenous fluid therapy ( on average 0.75 l electrolyte infusion ) in patients with af and the fact that just a minority of our study patients showed impaired left ventricular function , a known risk factor for developing haemodynamic instability .
first , we did not include a placebo group due to our concerns of leaving symptomatic patients untreated .
second , study treatment was not blinded , so we can not exclude some type of bias . however , our predefined study endpoints were not prone to subjective assessment .
third , we performed a single - centre trial and can not rule out that local standard of care affected study outcomes .
indeed , the administration of an electrolyte infusion to raise potassium values to high normal values during the screening phase might be linked with the absence of tdp arrhythmia or other polymorphic vt in our study patients .
forth , af duration prior the study inclusion was short , and most of our study patients had good ejection fraction and were relatively young .
vernakalant was superior to ibutilide in converting recent - onset af to sr in the emergency department setting .
this project was supported by a grant from the jubilaeumsfonds of the austrian national bank ( # 14891 to a.o.s ) . funding to pay the open access publication charges for this article | ### Summary:
: aimsibutilide is a rapid - acting antiarrhythmic drug with worldwide use for conversion of recent - onset atrial fibrillation .
vernakalant , approved in the eu in 2010 , is likewise used intravenously , with proven efficacy and safety compared with placebo and amiodarone in randomized clinical trials .
the aim of our study was to compare the time to conversion and the conversion rate within 90 min in patients with recent - onset atrial fibrillation treated with vernakalant or ibutilide.methods and resultsa randomized controlled trial registered at clinicaltrials.gov ( nct01447862 ) was performed in 100 patients with recent - onset atrial fibrillation treated at the emergency department of a tertiary care hospital .
patients received up to two short infusions of vernakalant ( n = 49 ; 3 mg / kg followed by 2 mg / kg if necessary ) or ibutilide ( n = 51 ; 1 mg followed by another 1 mg if necessary ) according to the manufacturer 's instructions . clinical and laboratory variables , adverse events , conversion rates , and time to conversion were recorded .
time to conversion of af to sinus rhythm was significantly shorter in the vernakalant group compared with the ibutilide group ( median time : 10 vs. 26 min , p = 0.01 ) , and likewise the conversion success within 90 min was significantly higher in the vernakalant group ( 69 vs. 43% , log - rank p = 0.002 ) .
no serious adverse events occurred.conclusionvernakalant was superior to ibutilide in converting recent - onset atrial fibrillation to sinus rhythm in the emergency department setting . |
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: we designed and developed a stochastic simulation model that captures hiv disease progression and transmission in order to evaluate alternative vl monitoring strategies .
the model tracked patient demographics , cd4 cell counts , individual adherence to art , and presence of virologic failure ( a schematic is presented in figure 1 ) .
the model was used to optimize monitoring strategies at different cost - effectiveness ( ce ) thresholds ( cets ) .
we use the cet to indicate the upper bound of societal resources that are considered affordable to gain 1 quality - adjusted life - year ( qaly ) .
low - income countries have a lower cet than middle - income countries and in this analysis we use the gross domestic product ( gpd ) per capita in 2013 as a benchmark .
we simulated a population of 100000 individuals that was age- , education- , and gender - matched to uganda s 2011 nationally representative demographic and health survey over a 10-year time horizon . at baseline ,
the mean age among hiv - infected individuals was 36 years old , 61% were women , and 25% completed primary school education .
we used data from the swiss hiv cohort study ( shcs ) to estimate the risk of virologic failure in different hiv risk groups .
we used the shcs because it contained detailed , longitudinal information on adherence , virologic failure , and cd4 cell counts . while patients in the shcs live with hiv in a different environment from low - resource countries , we considered the use of the shcs acceptable for our primary model population if the events under study could be considered context - independent .
we used shcs to assess the risk of virologic failure given self - reported adherence status , and the implications of failure for cd4 cell change .
we analyzed longitudinal data from 5251 art - naive shcs patients ( 95414 patient visits ) .
we used a mixed - effects logistic regression model fitted to the shcs self - reported adherence data to model a patient s current adherence status ( a binary outcome ) , as a logit function of previous adherence status , age , gender , education , and time since last measurement .
self - reported nonadherence was defined as having missed > 2 doses in the month previous to a biannual shcs cohort visit and was measured in the shcs data with a 2-item questionnaire that has been shown to predict virologic failure , presence of viral resistance , and progression of hiv disease [ 1517 ] .
virologic failure in the shcs data was defined as ( i ) 2 consecutive measurements of a vl > 200 copies / ml , ( ii ) 1 vl measurement > 1000 copies / ml , or ( iii ) not reaching virologic suppression within 6 months of either art initiation or regimen change . for patients on first - line therapy who were not in virologic failure in the previous month , we estimated the probability of failure at any month ( binary outcome ) as a logit function of current adherence status , time on art , age , gender , and time between measurements , and used the predicted probabilities to parameterize the simulation model . for patients on second - line therapy , we use a fixed monthly probability of failure , which does not depend on individual patient characteristics .
we also estimated the probability of spontaneous resuppression after the first occurrence of virologic failure in the shcs data , depending on current adherence status .
we assumed that if patients do not resuppress within a month , then they remain in virologic failure until a switch in regimen occurs .
we estimated cd4 cell count changes using quantile regression models fitted to shcs data to capture the distribution of the data , and estimated the monthly change in cd4 cell count as a function of previous cd4 cell count , time since art initiation , cd4 cells at art initiation , age , and gender .
we used data from uganda to estimate age- and gender - specific mortality by cd4 cell counts .
afterward , patients are monitored according to the policy we evaluate , or upon development of an aids - defining opportunistic infection ( oi ) .
cd4 cell specific oi rates are adjusted in calibration to match oi rates reported in clinical data from uganda [ 1 , 20 ] .
we use who life tables to estimate age- and gender - specific mortality . in our simulation model ,
if virologic failure is detected during monitoring on first - line therapy , patients return for a follow - up vl test in the next month .
if virologic failure is still present ( spontaneous resuppression has not occurred ) , the patient is switched to second - line therapy .
we did not model regimen switching for patients on second - line art , and assumed annual vl monitoring for all patients on second - line therapy regardless of failure status .
we tracked monthly costs based on the patient s art regimen , administration of vl measurement , and cd4 cell count ( < 250 cells/l or not ; supplementary tables 3 and 4 ) [ 2326 ] .
we estimate the number of secondary hiv infections in the community as a function of the number of individuals in virologic failure in the population simulated .
we track the number of patient - months spent in failure during the time horizon of our simulation , and calculate the number of secondary infections as a function of the average number of partners , hiv prevalence ( ie , the probability that a partner is hiv - infected ) , probability of hiv transmission per sex act for patients in failure , and the average number of sex acts per month , all parameterized using data from uganda [ 2831 ] .
we then also estimate the loss in qalys and gain in costs per secondary infection generated assuming that the newly infected individual would be placed on art and subject to the same monitoring policy , and adjust the costs and qalys resulting from our simulation according to these estimates .
we report the average total discounted costs and qalys per patient over the 10-year time horizon .
, patients are monitored every 1 , 3 , 6 , 12 , or 24 months .
we use the model to search for monitoring policies that better reflect a patient s optimal monitoring frequency based on patient characteristics . as a simple example , a patient who reports being nonadherent should have vl monitoring sooner than a similar patient reporting good adherence , even if both patients appear to be currently suppressed .
we use a stochastic optimization approach where , given patient characteristics ( time since art initiation , current adherence status , age , sex , and education level ) , we optimize the time until the next vl test by maximizing the average net monetary benefit ( nmb ) , where nmb = qalys cet costs . a key feature in determining an adaptive policy
, we recover a continuum of adaptive strategies , the costs and qalys of which should define the cost - effectiveness frontier as each adaptive policy is optimized to provide the most benefit at a given cost per qaly . for this analysis
, we show findings for cet of us$572/qaly ( uganda s gdp per capita in 2013 ) , and 3 , 10 , 30 , 50 , and 100 times uganda s per - capita gdp , where we note that $ 57200 per qaly is similar to the gdp per capita in organisation for economic co - operation and development countries .
we designed and developed a stochastic simulation model that captures hiv disease progression and transmission in order to evaluate alternative vl monitoring strategies .
the model tracked patient demographics , cd4 cell counts , individual adherence to art , and presence of virologic failure ( a schematic is presented in figure 1 ) .
the model was used to optimize monitoring strategies at different cost - effectiveness ( ce ) thresholds ( cets ) .
we use the cet to indicate the upper bound of societal resources that are considered affordable to gain 1 quality - adjusted life - year ( qaly ) .
low - income countries have a lower cet than middle - income countries and in this analysis we use the gross domestic product ( gpd ) per capita in 2013 as a benchmark .
we simulated a population of 100000 individuals that was age- , education- , and gender - matched to uganda s 2011 nationally representative demographic and health survey over a 10-year time horizon . at baseline ,
the mean age among hiv - infected individuals was 36 years old , 61% were women , and 25% completed primary school education .
we used data from the swiss hiv cohort study ( shcs ) to estimate the risk of virologic failure in different hiv risk groups .
we used the shcs because it contained detailed , longitudinal information on adherence , virologic failure , and cd4 cell counts . while patients in the shcs live with hiv in a different environment from low - resource countries , we considered the use of the shcs acceptable for our primary model population if the events under study could be considered context - independent .
we used shcs to assess the risk of virologic failure given self - reported adherence status , and the implications of failure for cd4 cell change .
we analyzed longitudinal data from 5251 art - naive shcs patients ( 95414 patient visits ) .
we used a mixed - effects logistic regression model fitted to the shcs self - reported adherence data to model a patient s current adherence status ( a binary outcome ) , as a logit function of previous adherence status , age , gender , education , and time since last measurement .
self - reported nonadherence was defined as having missed > 2 doses in the month previous to a biannual shcs cohort visit and was measured in the shcs data with a 2-item questionnaire that has been shown to predict virologic failure , presence of viral resistance , and progression of hiv disease [ 1517 ] .
virologic failure in the shcs data was defined as ( i ) 2 consecutive measurements of a vl > 200 copies / ml , ( ii ) 1 vl measurement > 1000 copies / ml , or ( iii ) not reaching virologic suppression within 6 months of either art initiation or regimen change . for patients on first - line therapy who were not in virologic failure in the previous month , we estimated the probability of failure at any month ( binary outcome ) as a logit function of current adherence status , time on art , age , gender , and time between measurements , and used the predicted probabilities to parameterize the simulation model . for patients on second - line therapy ,
we use a fixed monthly probability of failure , which does not depend on individual patient characteristics .
we also estimated the probability of spontaneous resuppression after the first occurrence of virologic failure in the shcs data , depending on current adherence status .
we assumed that if patients do not resuppress within a month , then they remain in virologic failure until a switch in regimen occurs .
we estimated cd4 cell count changes using quantile regression models fitted to shcs data to capture the distribution of the data , and estimated the monthly change in cd4 cell count as a function of previous cd4 cell count , time since art initiation , cd4 cells at art initiation , age , and gender .
we used data from uganda to estimate age- and gender - specific mortality by cd4 cell counts .
afterward , patients are monitored according to the policy we evaluate , or upon development of an aids - defining opportunistic infection ( oi ) .
cd4 cell specific oi rates are adjusted in calibration to match oi rates reported in clinical data from uganda [ 1 , 20 ] .
we use who life tables to estimate age- and gender - specific mortality . in our simulation model ,
if virologic failure is detected during monitoring on first - line therapy , patients return for a follow - up vl test in the next month .
if virologic failure is still present ( spontaneous resuppression has not occurred ) , the patient is switched to second - line therapy . we did not model regimen switching for patients on second - line art , and assumed annual vl monitoring for all patients on second - line therapy regardless of failure status .
we tracked monthly costs based on the patient s art regimen , administration of vl measurement , and cd4 cell count ( < 250 cells/l or not ; supplementary tables 3 and 4 ) [ 2326 ] .
we estimate the number of secondary hiv infections in the community as a function of the number of individuals in virologic failure in the population simulated .
we track the number of patient - months spent in failure during the time horizon of our simulation , and calculate the number of secondary infections as a function of the average number of partners , hiv prevalence ( ie , the probability that a partner is hiv - infected ) , probability of hiv transmission per sex act for patients in failure , and the average number of sex acts per month , all parameterized using data from uganda [ 2831 ] .
we then also estimate the loss in qalys and gain in costs per secondary infection generated assuming that the newly infected individual would be placed on art and subject to the same monitoring policy , and adjust the costs and qalys resulting from our simulation according to these estimates .
we report the average total discounted costs and qalys per patient over the 10-year time horizon .
, patients are monitored every 1 , 3 , 6 , 12 , or 24 months .
we use the model to search for monitoring policies that better reflect a patient s optimal monitoring frequency based on patient characteristics . as a simple example ,
a patient who reports being nonadherent should have vl monitoring sooner than a similar patient reporting good adherence , even if both patients appear to be currently suppressed .
we use a stochastic optimization approach where , given patient characteristics ( time since art initiation , current adherence status , age , sex , and education level ) , we optimize the time until the next vl test by maximizing the average net monetary benefit ( nmb ) , where nmb = qalys cet costs .
a key feature in determining an adaptive policy is the ce threshold . by varying the cet value
, we recover a continuum of adaptive strategies , the costs and qalys of which should define the cost - effectiveness frontier as each adaptive policy is optimized to provide the most benefit at a given cost per qaly . for this analysis
, we show findings for cet of us$572/qaly ( uganda s gdp per capita in 2013 ) , and 3 , 10 , 30 , 50 , and 100 times uganda s per - capita gdp , where we note that $ 57200 per qaly is similar to the gdp per capita in organisation for economic co - operation and development countries .
we calibrated our model to data from a randomized clinical trial of hiv laboratory monitoring strategies conducted in uganda and zimbabwe . in the trial , 3321 art - naive patients with cd4 counts < 200 cells/l at art initiation were randomized to 2 monitoring arms : laboratory and clinical monitoring .
our model closely matches several key quantities from the trial such as 5-year mortality , oi - free survival , and percentage of patients with cd4 cell counts > 200 cells/l ( for details , see supplementary appendix ) .
for example , we estimate that a 35-year - old woman who has been on art for 2 years and who reports being adherent would optimally have her next vl test in 12 months in uganda , and in 6 months in contexts with ce threshold similar to south africa .
third , as time since art initiation increases without loss of virologic control , patients should be monitored less and less frequently .
our model suggests that the 35-year - old woman in the example above should optimally be monitored in 14 months after 4 years on art in uganda .
figure 2 shows an example of adaptive policy where we hold gender , age , and education level constant and vary the cet and the adherence status .
the figure plots the optimized vl monitoring interval vs the time since art initiation and shows the lengthening monitoring intervals with increasing time on art , for adherent patients , and at lower ce thresholds .
example of adaptive policy : male , age 1520 years , primary education or less . abbreviations : art , antiretroviral therapy ; gdp , gross domestic product .
the adaptive policies evaluated were generally on the cost - effectiveness frontier , achieving the highest qalys at their respective costs . monitoring at fixed intervals of 24 months is the least costly vl monitoring strategy we evaluated ( $ 3445 on average per patient in total costs , standard error [ se ] = $ 3.7 , discounted over 10 years ) , but also yields the smallest number of qalys ( 6.034 , se = 0.005 ) .
the adaptive policy optimized for the ugandan resource context ( cet = ugandan gdp per capita ) is cost - effective with an incremental cost - effectiveness ratio ( icer ) of $ 491/qaly relative to monitoring every 24 months .
furthermore , monitoring every 24 months resulted in an additional 2 months average time spent in virologic failure per patient during the simulated 10-year horizon compared to the optimized adaptive policy at uganda s gdp per capita .
if decision makers are willing to spend up to 3 times uganda s gdp per capita , then using the adaptive policy optimized for that cet provides the highest benefits ( 6.142 qalys ) , icer of $ 1311/qaly compared to the first adaptive policy .
however , the fixed 12-month interval monitoring policy yields similar outcomes to the adaptive policy optimized for a cet of 3 times ugandan gdp per capita ( 6.135 qalys at a cost of $ 3518 ) , icer of 1485 ( $ /qaly ) compared to the adaptive policy for ugandan gdp per capita .
the adaptive policies optimized for 10 , 50 , and 100 times uganda s gdp per capita are on the cost - effectiveness frontier , dominating the fixed - interval monitoring policies of monitoring every 3 months and 6 months .
the costs and qalys achieved by all policies are summarized in tables 1 and 2 and in figure 3 .
average per - person costs and quality - adjusted life - years of fixed - interval monitoring policies abbreviations : qaly , quality - adjusted life - years ; se , standard error ; us , united states .
average per - person costs and quality - adjusted life - years of adaptive monitoring policies abbreviations : cet , cost - effectiveness threshold ; qaly , quality - adjusted life - year ; se , standard error ; us , united states .
= adaptive policy optimized for a cost - effectiveness threshold = x times the gross domestic product per capita of uganda ( us$572 ) .
the average cumulative number of months that a patient spends in failure is shown in figure 4 .
compared to fixed- interval policies , adaptive policies incur similar or fewer months in virologic failure on average , and therefore generate fewer secondary infections on average per patient on art .
all 6 adaptive policies we simulated incurred fewer months in failure than the fixed - interval policy that monitors every 24 months , and the adaptive policies for the 3 highest cet values ( 30 , 50 , and 100 times uganda s gdp per capita ) resulted in fewer months spent in failure than the 6-month fixed - interval policy . despite costing on average $ 204 less per patient , the adaptive policy optimized for a cet of 30 times ugandan gdp per capita achieves similar averages of months spent in failure and secondary infections ( 2.7 and 0.144 , respectively , over 10 years simulated ) and only 0.008 qalys fewer than the fixed - interval policy that monitors every 3 months .
abbreviations : cet , cost - effectiveness threshold ; ci , confidence interval ; gdp , gross domestic product .
we calibrated our model to data from a randomized clinical trial of hiv laboratory monitoring strategies conducted in uganda and zimbabwe . in the trial , 3321 art - naive patients with cd4 counts < 200 cells/l at art initiation were randomized to 2 monitoring arms : laboratory and clinical monitoring .
our model closely matches several key quantities from the trial such as 5-year mortality , oi - free survival , and percentage of patients with cd4 cell counts > 200 cells/l ( for details , see supplementary appendix ) .
for example , we estimate that a 35-year - old woman who has been on art for 2 years and who reports being adherent would optimally have her next vl test in 12 months in uganda , and in 6 months in contexts with ce threshold similar to south africa .
third , as time since art initiation increases without loss of virologic control , patients should be monitored less and less frequently .
our model suggests that the 35-year - old woman in the example above should optimally be monitored in 14 months after 4 years on art in uganda .
figure 2 shows an example of adaptive policy where we hold gender , age , and education level constant and vary the cet and the adherence status .
the figure plots the optimized vl monitoring interval vs the time since art initiation and shows the lengthening monitoring intervals with increasing time on art , for adherent patients , and at lower ce thresholds .
example of adaptive policy : male , age 1520 years , primary education or less .
the adaptive policies evaluated were generally on the cost - effectiveness frontier , achieving the highest qalys at their respective costs . monitoring at fixed intervals of 24 months is the least costly vl monitoring strategy we evaluated ( $ 3445 on average per patient in total costs , standard error [ se ] = $ 3.7 , discounted over 10 years ) , but also yields the smallest number of qalys ( 6.034 , se = 0.005 ) . the adaptive policy optimized for the ugandan resource context ( cet = ugandan gdp per capita ) is cost - effective with an incremental cost - effectiveness ratio ( icer ) of $ 491/qaly relative to monitoring every 24 months .
furthermore , monitoring every 24 months resulted in an additional 2 months average time spent in virologic failure per patient during the simulated 10-year horizon compared to the optimized adaptive policy at uganda s gdp per capita .
if decision makers are willing to spend up to 3 times uganda s gdp per capita , then using the adaptive policy optimized for that cet provides the highest benefits ( 6.142 qalys ) , icer of $ 1311/qaly compared to the first adaptive policy .
however , the fixed 12-month interval monitoring policy yields similar outcomes to the adaptive policy optimized for a cet of 3 times ugandan gdp per capita ( 6.135 qalys at a cost of $ 3518 ) , icer of 1485 ( $ /qaly ) compared to the adaptive policy for ugandan gdp per capita .
the adaptive policies optimized for 10 , 50 , and 100 times uganda s gdp per capita are on the cost - effectiveness frontier , dominating the fixed - interval monitoring policies of monitoring every 3 months and 6 months .
the costs and qalys achieved by all policies are summarized in tables 1 and 2 and in figure 3 .
average per - person costs and quality - adjusted life - years of fixed - interval monitoring policies abbreviations : qaly , quality - adjusted life - years ; se , standard error ; us , united states .
average per - person costs and quality - adjusted life - years of adaptive monitoring policies abbreviations : cet , cost - effectiveness threshold ; qaly , quality - adjusted life - year ; se , standard error ; us , united states .
= adaptive policy optimized for a cost - effectiveness threshold = x times the gross domestic product per capita of uganda ( us$572 ) .
the average cumulative number of months that a patient spends in failure is shown in figure 4 .
compared to fixed- interval policies , adaptive policies incur similar or fewer months in virologic failure on average , and therefore generate fewer secondary infections on average per patient on art .
all 6 adaptive policies we simulated incurred fewer months in failure than the fixed - interval policy that monitors every 24 months , and the adaptive policies for the 3 highest cet values ( 30 , 50 , and 100 times uganda s gdp per capita ) resulted in fewer months spent in failure than the 6-month fixed - interval policy . despite costing on average $ 204 less per patient , the adaptive policy optimized for a cet of 30 times ugandan gdp per capita achieves similar averages of months spent in failure and secondary infections ( 2.7 and 0.144 , respectively , over 10 years simulated ) and only 0.008 qalys fewer than the fixed - interval policy that monitors every 3 months .
abbreviations : cet , cost - effectiveness threshold ; ci , confidence interval ; gdp , gross domestic product .
we model the important clinical and public health decision of how to tailor vl monitoring intervals of hiv patients on art to individual patient characteristics , adherence behavior , and disease dynamics , and we evaluate the cost- effectiveness of such adaptive intervals relative to fixed - interval monitoring policies . we find that adaptive policies outperform fixed - interval monitoring policies , by margins that are small in low - resource settings but potentially large in high- resource settings .
our analysis suggests that in contexts such as uganda , monitoring at fixed 12-month intervals performs closely to the adaptive monitoring policies that define the cost - effectiveness frontier . due to its simplicity
, the former policy may be a good alternative to implement in resource - limited settings . in higher- resource contexts ,
however , adaptive monitoring policies could lead to significant cost savings . in settings with gdp per capita of $ 15000$50000
, we estimate that $ 200$1100 could be saved for each patient on art by using adaptive monitoring policies instead of fixed 1- to 3-month monitoring policies .
the optimal monitoring frequency depends crucially on the amount of resources available in the respective setting . for this reason
, we embed a cet in our algorithm when optimizing for adaptive monitoring policies , which we then vary to recover adaptive policies in a range of settings .
policies that monitor more frequently tend to achieve high qalys but also incur more costs , and therefore perform better at high cets .
the small performance margin of adaptive policies at low cets compared to fixed - interval policies can be explained by the fact that the long monitoring intervals imposed by the resource constraints translate to a loss in accuracy when predicting individualized risks over long time horizons . on the other hand , at higher cet values , monitoring intervals are generally smaller , and individualized ( differentiated ) monitoring policies can better take advantage of short - term discrepancies in the risk of failure for different patients .
in developing our simulation model , we use shcs data representing a diverse population of hiv - infected individuals with low loss of follow - up to model patient self - reported adherence , vl failure , and cd4 cell dynamics . analyzing this data also allowed us to optimize for adaptive policies that depend on patient characteristics , time on art , and , importantly , on self - reported adherence .
we find that patients who report nonadherence behaviors are at an increased risk of vl failure , in accordance with existing studies [ 1517 , 3436 ] , and therefore monitoring policies should test them more frequently . similarly
, our analysis of shcs data found that the risk of vl failure decreases after the initial 6 months on art , and thus adaptive monitoring intervals tend to become larger the longer the patients have been on treatment .
our study also confirms previous findings that monitoring vl every 12 months provides a reasonably cost - effective vl monitoring policy , but extends the analysis to find other adaptive monitoring policies that outperform fixed - interval policies at various expenditure levels .
first , we use data from a resource - rich setting ( switzerland ) to inform a model for resource - limited settings such as uganda .
specifically , we use the swiss data to estimate nonadherence given sociodemographic factors such as age and education , to estimate failure from first - line therapy given nonadherence , and cd4 chances given failure status . generalizing the probability of nonadherence from switzerland to resource - limited countries
is the most tenuous assumption , while the others tend to be more intrinsic to hiv and thus may be similar between populations .
for this reason , we test the sensitivity of our model to assumptions about nonadherence , and we simulate a clinical trial performed in uganda to check that key outcomes such as mortality and cd4 cell progression match historical values ( supplementary appendix ) .
finally , our simulation model does not explicitly model hiv transmission or changes in adherence behavior arising from varying monitoring intervals .
our model does track , however , the number of months that each simulated patient spends in virologic failure , which allows estimation of the number of secondary infections from each policy using a well - known result . our study can inform decisions about when to test the vl of hiv - infected patients . we provide a decision support tool ( menet.umn.edu/~negoescu/downloads.html ) that returns a monitoring interval as a function of patient age , gender , education , time since art initiation , adherence , and resource setting .
our analysis highlights the important role played by patient adherence and time since art as well as the resource context in determining the frequency of virologic monitoring .
consisting of data provided by the authors to benefit the reader , the posted materials are not copyedited and are the sole responsibility of the authors , so questions or comments should be addressed to the corresponding author .
| ### Summary:
: summaryfocusing on patients most at risk of virologic failure improves the efficiency of viral load monitoring , most prominently in high - resource settings . in uganda ,
monitoring every 12 months is the next most efficient monitoring policy if an adaptive policy is unavailable . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: extrahepatic biliary atresia ( ba ) is the most common cause of neonatal obstructive jaundice with an incidence of 1 in 10,000 live births
. progressive damage of extrahepatic and intrahepatic bile ducts secondary to inflammation may occur , leading to fibrosis , biliary cirrhosis , and eventual liver failure .
a degree of hepatic fibrosis is invariably present at initial surgery and can be graded histologically .
portal hypertension ( pht ) has been reported in 34 - 76% of ba patients , and it is the most serious late complication .
it manifests as ascites ( 63% ) and esophageal varices ( 49% ) with bleeding complications in 20 - 60% .
pht is associated with a hyperdynamic state characterized by splanchnic vasodilation and increased blood volume as a result of the increase in local and systemic vasodilators .
nitric oxide ( no ) has been recognized as the most important vasodilator molecule that mediates the excessive arterial vasodilation observed in pht .
this study aims to identify the incidence and severity of pht in ba patients and to monitor its progress after kp using no levels in peripheral blood .
it is a prospective cross - sectional study conducted over a period of 2 years ( june 2012 to june 2014 ) .
ethical clearance for the study was obtained from the institute ethics committee vide letter number iesc / t-212/01.06.2012 .
all children presenting with ba were enrolled in the study after taking informed consent from the parents / legal guardians .
blood levels of no and liver function tests were done at presentation and at 1-month , 3-month , and 6-month follow - up .
blood concentration of no is measured as its stable metabolite nitrate and nitrite spectrophotometrically at 540 nm using griess reaction .
blood levels of no in age - matched patients admitted for diseases other than ba were taken as control after taking consent .
the patients also underwent upper gastrointestinal endoscopy ( ugie ) at presentation and at 6-month follow - up to look for presence / progress / resolution of esophageal varices .
esophageal varices were graded as follows :
grade 1 : small straight varices.grade 2 : enlarged tortuous varices occupying less than one - third of the lumen.grade 3 : large coil - shaped varices occupying more than one - third of the lumen .
grade 2 : enlarged tortuous varices occupying less than one - third of the lumen .
grade 3 : large coil - shaped varices occupying more than one - third of the lumen .
minilaparotomy was done and if the gallbladder was not atretic , peroperative cholangiogram was performed and diagnosis was confirmed .
portal pressure ( pp ) measurement was done after surgical access and before any mobilization of the liver and biliary tree .
the system used for pressure measurement was datex ohmeda s/5 monitor ( range of measurement = 40 to 320 mmhg , accuracy : 5% or 2 mmhg ) attached to a pressure transducer with continuous flush device and stop cock mounted at the level of the abdomen to avoid any error due to height ( 10 mmhg for every 13.6 cm difference ) .
a 24-g intravenous cannula , attached to saline - filled pressure tubing , was inserted directly into one of the tributaries of gastroepiploic vein and pp was measured using the setup .
the patients were followed at 1 month , 3 months , and 6 months post kp .
the patients were declared jaundice free when they achieved bilirubin levels < 1.5 mg / dl .
the data analysis was done using stata software version 11 ( statacorp lp , texas , usa ) .
blood levels of no in ba patients were compared with the controls and within themselves using paired t - test .
the correlation between the no levels and pp was calculated using spearman rank correlation coefficient .
six patients were lost to follow - up , one in the first month and the remaining five at 3-month follow - up .
the mean age of presentation was 2.7 months ( range 1 - 4 months ) . there were 14 ( 41% ) patients who presented before 60 days of life , 10 ( 29.5% ) patients presented between 61 days and 90 days , and the remaining 10 ( 29.5% ) patients presented after 90 days of age .
all patients were clinically jaundiced and they passed high colored urine and acholic stools . on clinical examination ,
15 ( 44% ) patients had soft hepatomegaly , 19 ( 56% ) patients had firm hepatomegaly , and 15 ( 44% ) patients had splenomegaly . at 6-month follow - up , 12 ( 43% ) patients were jaundice free while 16 ( 53% ) patients continued to have jaundice .
the mean bilirubin level at presentation was 10.10 3.08 mg / dl ( range 6.2 - 23.4 mg / dl ) .
post kp , there was a statistically significant fall in the mean bilirubin level from the preoperative levels . at 1 month , it was 7.16 3.3 mg / dl , at 3 months it was 6.3 3.9 mg / dl , and at 6 months it was 5.8 4.8 mg / dl ( p = 0.0001 , 0.0003 and 0.0005 respectively ) .
there was no significant difference in the mean preoperative bilirubin level of patients who were jaundice free at 6 months and those who continued to have jaundice ( p = 0.2 ) .
the mean intraoperative portal venous pressure was 21.3 5.4 mmhg ( range 9 - 34 mmhg ) . the mean preoperative blood levels of no in the study group and the control group were 18.48 4.17 mol / l and 4.64 2.32 mol / l , respectively .
no levels at 1-month , 3-month , and 6-month follow - up were 11.94 5.62
mol / l , 10.79 6.02 mol / l , and 9.93 6.53 mol / l , respectively [ figure 1 ] .
the fall in the no levels in the immediate postoperative period was statistically significant ( p < 0.005 ) .
however , there was no significant fall in no levels during subsequent follow - up , i.e. , between 1 month and 3 months and 3 and 6 months .
blood no levels in ba patients : preoperative and after kp at 1-month , 3-month , and 6-month follow - up ( original ) on ugie at presentation , 19 ( 56% ) patients had esophageal varices .
grade 1 varices were present in 12 ( 35% ) patients , while 7 ( 20% ) patients had grade 2 esophageal varices .
the mean pp in patients with absent varices was lower ( 17.46 mmhg ) than the mean pp in patients with grade 1 varices ( 23.58 mmhg ) and grade 2 varices ( 25.71 mmhg ) , and the difference was statistically significant between the groups with and without varices ( p = 0.002 ) .
however , the difference was not statistically significant between the groups with grade 1 and grade 2 varices ( p = 0.8 ) .
the mean preoperative no levels in the patients who did not have any varices were 15.37 3.42
mol / l and in those with grade 1 and grade 2 varices were 20.05 2.90 mol / l and 22.45 2.30
the difference in blood no level was again statistically significant between patients with and without varices ( p = 0.001 ) but not among the patients with grade 1 and grade 2 varices ( p = 0.33 ) .
preoperative blood no levels in ba patients with respect to grades of esophageal varices at presentation ( original ) ugie was also performed at 6-month follow - up in 28 patients .
one patient who continued to be clinically jaundiced at 6-month follow - up also had resolution of varices .
ugie at presentation and 6-month follow - up did not reveal any varices in two other patients who were still icteric at 6-month follow - up .
these patients showed a trend toward normalizing bilirubin levels ( mean bilirubin level at 6 months = 3.5 mg / dl ) but were clinically jaundiced .
five patients with persisting jaundice had progression of varices at the end of 6 months .
one developed new grade 1 varices , two had progression to grade 2 , and two others had progression to grade 3 varices .
the mean no levels at 6-month follow - up in patients with absent varices were 4.85 1.50 mol / l and in those with grade 1 , grade 2 , and grade 3 varices were 14.78 7.21 mol / l , 15.72 2.92 mol / l , and 19.35 1.08 mol / l , respectively [ figure 3 ] . at 6-month
follow - up , the difference in mean blood no levels between groups with and without varices was also statistically significant ( p < 0.001 ) .
blood no levels in ba patients with respect to grades of esophageal varices at 6-month follow - up after kp ( original ) there was no significant correlation between intraoperative pp with preoperative bilirubin level ( p = 0.28 ) , serum glutamic oxaloacetic transaminase ( sgot ) ( p = 0.648 ) , serum glutamic - pyruvic transaminase ( sgpt ) ( p = 0.517 ) , and alkaline phosphatase ( p = 0.282 ) .
there was also no significant correlation between preoperative no levels with bilirubin level ( p = 0.1 ) , sgot ( p = 0.372 ) , sgpt ( p = 0.452 ) , and alkaline phosphatase ( p = 0.254 ) at presentation .
ba is characterized by fibrotic obliteration of the lumen of all or a part of the extrahepatic biliary tree .
bile flow is impaired and liver inflammation , fibrosis , and cirrhosis sets in resulting in pht .
the mean intraoperative portal venous pressure in this study was 21.32 5.4 mmhg and the median pressure was 21 mmhg ( range 9 - 34 mmhg ) .
thus , all patients in the cohort had intraoperative pps greater than 8 mmhg . however , clinical manifestations of pht were not present in all ; 19 ( 56% ) patients had firm hepatomegaly , 15 ( 44% ) patients had splenomegaly , and 19 ( 56% ) patients had esophageal varices at presentation .
although pht is present in all ba patients , it varies in severity and manifests in some of the patients only .
variceal bleed , ascites , and hepatic decompensation are late manifestations of pht and may not be present in the initial months . if untreated , patients will continue to develop liver fibrosis and cirrhosis .
the mean pp in patients < 60 days old was 18.53 4.45 mmhg , in patients aged between 61 - 90 days , it was 20.33 3.07 mmhg and in those > 90 days old , it was 26.5 5.01 mmhg .
the difference in pp was statistically significant between patients aged < 90 days and those > 90 days ( p < 0.001 ) , but it was not significant between patients who were < 60 days old and those between 61 - 90 days ( p = 1 ) .
duche et al . also showed a positive correlation between age at surgery and pp index ( ppi ) .
median ppi in 113 ba patients at kasai operation was 15 cm of water ( 11 mmhg ) .
the higher median pp finding in our study may be due to the older age of presentation as compared to the above study that is 2.7 months versus 55 days .
shalaby et al . also measured portal venous pressure in ba patients at the time of kp and found a significant correlation between portal venous pressure and age at surgery . in our study , the patients who underwent successful kp and were jaundice free at 6-month follow - up and had considerably lower mean intraoperative pp ( 16.75 3.54 mmhg ) compared to those who continued to have jaundice ( 23.94 4.63 mmhg ) ( p < 0.001 ) [ figure 4 ] .
study which states that ba patients with elevated portal pressure at the time of kasai operation have lower chances of success of this procedure .
they concluded that the measurement of the ppi during kasai operation is simple and safe and better predicts the postoperative outcome than do the histological scores of liver fibrosis .
however , shalby et al . did not find any statistical difference in the median portal venous pressure between the group who cleared jaundice and those who did not clear their jaundice after kp .
relation between intraoperative pp and outcome at 6-month follow - up in ba patients after kp ( original ) in the cirrhotic model with pht , the circulatory state is hyperdynamic in the splanchnic bed and this is initiated by arterial vasodilatation . as demonstrated by niederberger ,
the levels of no in the peripheral venous blood of rats with pht were elevated and these levels come down with the normalization of portal hemodynamics .
this increased no production is responsible for the hemodynamic disturbances and sodium retention observed in the cirrhotic model . a study by vejchapipat et al .
also demonstrated increased no levels in peripheral blood of patients with extrahepatic portal vein obstruction , which declined after a successful lienorenal shunt surgery and remained low till the shunt was patent .
this study shows that all ba patients had pht and the mean no levels in peripheral blood were higher in the study group as compared to the controls .
this suggests that no might be the vasoactive agent that is directly responsible for the hyperdynamic portal venous circulation . on further analysis
, there seems to be a direct correlation between intraoperative pp and pre - operative no levels that is increased no levels are seen with higher pp ( r = 0.89 , p < 0.001 ) [ figure 5 ] .
relation between intraoperative pp and pre - operative blood no levels in ba patients ( original ) thus , no levels in peripheral blood closely follow the pp .
the regression equation no = 4.79 + 0.64 pp mmhg , r = 0.69 suggest that a rise of 0.64 mmhg in pp would lead to an increase in no levels by 1 mol / l , with co - efficient of determination 0.69 [ figure 5 ] . in this study , the patients who were jaundice free at 6-month follow - up had lower mean no levels preoperatively ( p < 0.001 ) and during subsequent 1-month ( p = 0.0014 ) , 3-month ( p = 0.0004 ) , and 6-month ( p = 0.0003 ) follow - up than those who still had jaundice [ table 1 ] .
thus , no levels in peripheral blood can be used to monitor progress of pht in the follow - up period .
patients with severe liver damage and an advanced degree of pht and hence a higher no levels , are more likely to have a failed kp .
pre - operative mean blood no levels and at 1-month , 3-month , and 6-month follow - up in patients with and without jaundice at 6 months following kp .
pht worsens with age , and it has an adverse effect on the outcome of kp .
portal venous pressure measurement is a simple and safe method reflecting the degree of liver damage and the severity of pht in ba patients .
peripheral blood no levels closely follow pp , and the higher levels are associated with poor outcomes .
| ### Summary:
: aim : to evaluate the incidence of portal hypertension ( pht ) in biliary atresia ( ba ) patients and to monitor its progress after kasai portoenterostomy ( kp ) by measuring nitric oxide ( no ) levels in peripheral blood.materials and methods : a prospective cross - sectional study conducted over a period of 2 years .
intraoperative portal pressure ( pp ) and blood no levels at presentation , 1-month , 3-month , and 6-month follow - up , were correlated with clinical and biochemical parameters in ba patients .
the mean no level in age - matched control group was 4.64 2.32 mol / l.results : thirty - four ba patients underwent kp over a period of 2 years .
the mean age of presentation was 2.7 months ( range 1 - 4 months ) .
the mean intraoperative pp was 21.3 5.4 mmhg .
the mean pp in patients aged < 60 days , 6190 days , and > 90 days was 18.53 4.45 mmhg , 20.33 3.07 mmhg , and 26.5 5.01 mmhg , respectively .
the mean pp in the patients who underwent successful kp was 16.75 3.54 mmhg while for those who continued to have jaundice it was 23.94 4.63 mmhg ( p < 0.001 ) . no levels closely followed the pp as shown by the regression equation no = 4.79 + 0.64 pp mmhg , r2 = 0.69 .
the mean no level at presentation was 18.48 4.17 mol / l and at 1-month , 3-month , and 6-month follow - up was 11.94 5.62 mol / l , 10.79 6.02 mol / l , and 9.93 6.53 mol / l , respectively ( p < 0.001 ) .
the difference in no levels was also statistically significant between the patients who cleared jaundice and those with persisting jaundice.conclusion:all ba patients had pht at presentation .
pht worsens with age and has an adverse effect on outcome of kp .
no levels in blood closely follow pp and higher levels are associated with poor outcome . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: a butterfly vertebra ( bv ) is a rare congenital anomaly resulting from a symmetric fusion
defect .
also known a sagittal cleft vertebra , this anomaly is usually asymptomatic and
detected incidentally .
a bv may be isolated or associated with other spinal anomalies such
as kyphoscoliosis , hemivertebrae , or spina bifida1 ; other congenital syndromes2,3,4,5 ; or chromosomal defects6 .
this anomaly was first described in 1844 by
rokitansky , who examined the 12th thoracic vertebra of a 55-year - old man7 . since then , only a few cases have been
reported in the english - language literature .
we herein present a case of bvs at two levels
in a 38-year - old man who was also diagnosed with behet s disease and psoriasis .
the ethics committee of bezmialem vakif university approved this case study , and informed
consent was obtained from the patient . a 38-year - old man presented with a 4-month history of neck and low back pain .
he had had
psoriasis since early childhood and behet s disease for 15 years ; his symptoms were
controlled with colchicine at 1.5 mg / day . on physical examination , he was 158 cm tall with a short neck and mild kyphosis of the
thoracic spine .
the range of motion of the cervical and lumbar spine was normal , but
painful .
an anteroposterior x - ray revealed split
vertebrae at t8 and l3 with two lateral halves , suggesting bvs .
lateral x - rays showed
anterior wedging of the t8 and l3 vertebrae , kyphosis at the t8 level , and loss of lumbar
lordosis ( fig .
1.a : lateral radiograph of the spine showing anterior wedging at the l3 and t9
vertebrae .
b : anteroposterior radiograph of the lumbosacral spine showing the bv at
l3 ) .
computed tomography ( ct ) of the thoracolumbar region revealed two hemivertebrae ,
each with a complete central cleft , at t8 and l3 and complementary vertebral shapes at the
adjacent vertebrae ( fig .
2.coronal ct showing the bvs at l3 ( a ) and t9 ( b ) and the complementary shapes of the
adjacent vertebrae ) .
cranial and spinal magnetic resonance imaging ( mri ) was also performed to identify
any associated anomalies .
cranial mri was normal , but c45 central protrusion was observed
on cervical mri .
thoracolumbosacral mri confirmed incarcerated t8 and l3 bvs and showed
bulging at the l45 and l5s1 levels ( fig . 3fig .
a : lateral radiograph of the spine showing anterior wedging at the l3 and t9
vertebrae .
b : anteroposterior radiograph of the lumbosacral spine showing the bv at
l3 coronal ct showing the bvs at l3 ( a ) and t9 ( b ) and the complementary shapes of the
adjacent vertebrae axial t1-weighted mri showing the sagittal cleft at the l3 vertebra
he was informed that the
abnormal changes in the thoracic and lumbar spine were benign conditions and that there was
no need for further treatment .
although congenital vertebral anomalies are common ( global prevalence of 0.51/1,000 live
births ) , a bv anomaly presenting as a sagittal cleft vertebra is rare8 .
if one fails to develop , a hemivertebra occurs . if both
centers fail to fuse at the midline , a bv results9 .
a bv may
be associated with complex congenital syndromes , such as pfeiffer , jarcho - levins , crouzon ,
or alagille syndrome , and may also be associated with chromosomal defects such as a 22q11
deletion2,3,4,5,6 . in our case ,
clinical
examination of other systems revealed no abnormalities or signs of the abovementioned
syndromes ; therefore , a chromosomal analysis was not performed .
diastematomyelia , kyphoscoliosis , bars , supernumerary lumbar vertebrae , and spina bifida
can each be associated with bv1 . in our
case , spinal mri was performed to identify other possible vertebral anomalies .
bvs were
found at two levels , resulting in kyphosis at the t8 level and a loss of lumbar lordosis at
the l3 level . to our knowledge ,
compensation for the anomalous vertebra by the adjacent cranial and caudal vertebrae is
called incarceration .
while a non - incarcerated hemivertebra or bv may impair the spinal
curve and cause a progressive spinal deformity , an incarcerated anomalous vertebra usually
does not cause progressive spinal deformity10 . in lateral radiographs , a bv may be confused with a compression fracture due to trapezoidal
or cuneiform anterior wedging .
however , a fractured bone with osteoporotic compression
results in irregular collapse of the vertebral body , and the upper and lower margins are not
involved to similar extents .
pathological vertebral fractures secondary to a neoplasm or
infection can lead to extensive bony destruction and disc space narrowing11 .
mri reveals altered signal intensity of
bone and soft tissue components , which can result from trauma or pathological conditions
such as infections and neoplasms .
a bv is easily detected in anteroposterior radiographs
because the split vertebra has two halves that are not displaced laterally , and they are
usually of the same size , resembling the wings of a butterfly .
delgado et al.12 and sonel et al.9 described an l3 bv with lumbar disc
protrusion at the l45 level .
cho et al.13 described symptomatic disc herniation arising from the sagittal
cleft of the l4 vertebra and confirmed the existence of nucleus pulposus in the sagittal
cleft .
similarly , our patient had an l3 bv and bulging at the l45 and l5s1 levels .
a bv is
considered asymptomatic , but the spinal biomechanics may be altered , increasing the
incidence of disc herniation and chronic low back pain . in patients with chronic low back
pain ,
trunk and lumbar stabilization exercises improve the activities of daily living and
quality of life14 , 15 .
our patient also presented with low back pain , and his symptoms
resolved with appropriate medical and physical therapy .
given the rarity of this anomaly ,
biomechanical and exercise studies on a large series of patients would be extremely
difficult .
, no association of this
anomaly with rheumatic diseases other than ankylosing spondylitis has been described .
we believe that these diseases occurred
coincidentally . despite the rarity of bv , awareness of this congenital anomaly | ### Summary:
: [ purpose ] a butterfly vertebra is a rare congenital anomaly resulting from a symmetric
fusion defect .
only a few cases of butterfly vertebra have been described .
this anomaly
may be isolated or associated with pfeiffer , jarcho - levins , crouzon , or alagille syndrome .
[ subject and methods ] we herein describe a 38-year - old man who presented with neck and low
back pain and was found to have butterfly vertebrae at the t9 and l3 levels .
he also had
behet s disease and psoriasis .
[ results ] the patient s symptoms improved with analgesics
and physiotherapy .
[ conclusion ] to our knowledge , butterfly vertebrae at two levels have
never been reported .
butterfly vertebrae may be confused with vertebral fractures in
lateral radiographs , and awareness of this anomaly is important for a correct
diagnosis . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the process whereby
proteins are polyubiquitinated and delivered
to the 26s proteasome for degradation involves several steps and is
fundamental to the maintenance of healthy levels of all proteins in
eukaryotic organisms . a prominent really interesting new gene ( ring)-type
third order ( e3 ) ubiquitin ligase , referred to as the cullin - ring - ligase-1
( crl1 ) or the skp1-cullin - f - box ( scf ) complex , consists of several
subunits including the s - phase kinase - associated protein 1 ( skp1 ) . in dictyostelium discoideum
,
the proline residue at position 143 of skp1 is hydroxylated by a cytoplasmic
prolyl hydroxylase ( phya ) .
we have recently
confirmed that the hydroxylation , by analogy to the hypoxia inducible
factor ( hif ) prolyl hydroxylases , delivers ( 2s,4r)-4-hydroxyproline ( hyp ) .
hydroxylation of skp1 is important for the proper
oxygen - dependence of differentiation of the organism into a fruiting
body to disperse spores .
polypeptide n - acetylglucosaminyl - transferase 1 ( gnt1 ) transfers n - acetylglucosamine ( glcnac ) from uridine diphosphate ( udp )
to hyp of skp1 .
the installation of
the first glcnac residue renders skp1 subject to further glycosylation
by the pgta ( 3galt/2fuct ) and agta ( galt ) glycosyltransferases , which modulate oxygen - dependence conferred by prolyl hydroxylation .
the hypothesized terminal structure , illustrated in figure 1 , has been validated for all but the linkage of
the terminal gal .
circular dichroism ( cd ) and small - angle x - ray scattering
( saxs ) , indicate that the glcnac residue promotes -helical
secondary structure and increased order of the polypeptide .
these post - translational modifications occur
in other unicellular eukaryotes , including toxoplasma gondii.(8,12,13 ) glycosylated region of
skp1 .
while a fundamental impact of
glycosylation on protein structure
and function has been widely appreciated for many years , the empirical
basis for structural changes is less well understood .
previous studies
have focused on the more ubiquitous o - glycosidic
linkages to serine and threonine residues .
prior to hydroxylation , the pyrrolidine ring
of the pro residue is likely to adopt a c-endo conformation
( scheme 1 ) .
x - ray crystallographic studies
show that the thr - pro peptide bond favors the trans conformation ( = 180 ) when the skp1 proteins
from saccharomyces cerevisiae or arabidopsis
thaliana are complexed to an f - box protein .
trans isomerism
might be important in skp1 folding , perhaps mediated by a thr - pro
prolyl isomerase . by analogy to recent
findings in the orthologous human hif , upon hydroxylation by a trans-4-prolylhydroxylase ,
there could be dramatic changes in the topology of this region of
skp1 , viz .
pyrrolidine ring - flip to the c-exo conformation and a reinforced preference for a trans amide bond ( = 180 ) , which may in turn influence processing
by gnt1 and f - box protein binding . with a glcnac residue installed ,
torsion angles about the glycosidic bond will contribute to recognition
by other proteins , including f - box proteins and the 3galt/2fuct
that introduces the next two monosaccharides .
hydroxyproline glycosides
are common in plants ; however , no examples
have been reported to - date in mammalian systems . in 2007 ,
trans isomerization of a family of proline derivatives , ac - pro*-nhme where
pro * was l - proline ( pro ) , trans-4-hydroxy - l - proline ( hyp ) , trans-4-tert - butoxy - l - proline , -(1,4)-galactosyl - trans-4-hydroxy - l - proline [ -(1,4)-gal - hyp ] , and -(1,4)-galactosyl - trans-4-hydroxy - l - proline [ -(1,4-gal)-hyp ]
. the surprising result of this work was that ,
within experimental error , the equilibrium constants and rate constants
were similar for all compounds .
we report herein that for a dipeptide
that emulates the thr - pro sequence in
skp1 there are noteworthy changes that correlate with recent findings
on the f - box binding capacity of the isoforms of skp1 .
we prepared dipeptides 14 ( scheme 2 ) that track the initial post - translational modifications
of skp1 and incorporate the preceding thr residue .
we end - capped the
dipeptides to mimic the amide backbone of the protein and to eliminate
electrostatic effects that arise from ionizable groups . at the outset , we did not know the configuration at c of
the hydroxyproline residue and thus included cis-4-hydroxy - l - proline ( hyp ) in our repertoire of proline analogues .
specifically
compounds 2 and 3 were synthesized and used
to confirm the 4r configuration of the hydroxproline
residue in skp1 .
this compound represents the glcnac
analogue of ac-[-(1,4)gal]-hyp - nhme described previously by
schweizer and co - workers .
full details
of the synthesis of the compounds depicted in scheme 2 are provided in the supporting information . in the case of glycosides 4 and 5 ,
glycosylation
was performed with thioglycoside donor 6 using nis / agotf
activation and an appropriate carbamate
protected hydroxyproline ester .
analysis of the h nmr j coupling constants j1 and j2 ( ,
etc . as defined
for compound 1 in scheme 2 ) gave
an indication of the conformational preference of the pyrrolidine
ring in each compound ( table 1 ) .
according
to the literature , in a c-exo ring pucker
both j - values are in the specific limiting range
of 711 hz , sometimes even converging to produce an apparent
triplet . in the c-endo ring
pucker
there are two quite different dihedral angles between h
and the neighboring h protons , giving rise to distinct coupling
constants in the ranges 23 and 610 hz . in the case
of a twist conformation , dynamically
thus , the pyrrolidine rings in compounds 2 , 4 , and 5 adopt a c-exo conformation .
the j values could not be determined for compound 1 due to
overlap between pro h and thr h signals . for dipeptide 3 containing hyp , the j - values do not fit
either profile but are in agreement with those reported for ac - hyp - ome
by owens et al . and may signify a slightly
different conformation , viz .
not determined
due to overlap between
pro h and thr h. while two species are evident , the
two c signals appear to be coincident . on the time scale of the c nmr experiment
a single , averaged species was observed .
the value in parentheses represents
a signal due to the minor conformation . the electron - withdrawing nature and r - configuration
of substituents at c are attributed with favoring the c-exo conformation of the pyrrolidine ring and inter
alia the trans conformation of the preceding
prolyl peptide bond .
the c nmr chemical shift for c
has been used to assess the strength of the electron - withdrawing substituents ;
our results appear in table 1 .
hydroxylation
at c leads to a significant downfield shift from 23.6 to 69.7
ppm .
glycosylation further deshields the c nucleus from the
magnetic field , leading to an additional 6 ppm shift downfield upon
glycosylation of hydroxyproline , in accord with the observations of
schweizer and co - workers upon -d - galactosylation .
the j - values and c chemical
shifts reported in table 1 are very similar
to those reported for the ac - pro*-nhme series , implying that the additional thr residue does not affect
pyrrolidine ring conformation .
the thermodynamics of the cis trans isomerization were studied
by nmr as described previously.kt/c values were determined
at 5 temperature intervals from 25
to 85 c , by integration of well - resolved signals for protons
associated with the cis and trans conformations .
all peptides demonstrated a decrease
in kt / c with an increase in temperature , and the linear nature of the plots
indicates that h and s are independent of temperature .
vant hoff plots
for compounds 1 ( ) , 2 ( ) , 4 ( ) , and 5 ( ) . in the case of the dipeptides , one of the most
useful signals in
these studies ,
vis - - vis resolution and intensity , was the
doublet at 1.25 ppm , attributable to the methyl group
( h ) of the thr residue . at lower temperatures , there was excellent
resolution between the upfield ( cis ) and downfield
( trans ) signals .
an increase in temperature was accompanied
by a move toward coalescence of the two signals ; however , complete
coalescence was not observed within the temperature range accessible
in d2o . broadening and partial
coalescence of the signals in the case of glycosylated dipeptide 4 led to omission of the 85 c data point ( figure 2 ) , since integration of the two signals was not
possible .
the incidence of cis prolyl peptide
bonds , when
preceded by a thr residue , has been estimated at 2.9% based on crystallographic
data for proteins . in shorter peptides ,
without secondary structure ,
larger acyl groups n - terminal
to the pro residue have a larger steric bias toward the trans conformation .
this notwithstanding , kt / c for dipeptide 1 is low in the context
of other dipeptides we have studied : ac - gly - pro - nhme ( kt / c 5.5 in d2o at 298 k ) and
ac - phe - pro - nhme ( kt / c 2.2 ) .
the latter is expected to favor
the cis conformation due to an aromatic proline
interaction .
as anticipated , hydroxylation of the proline residue led to a significant
shift
in favor of the trans peptide bond ( scheme 3 , table 2 ) .
this arises from
stereoelectronic effects that favor a c-exo conformation of the pyrrolidine ring that , in - turn , aligns the peptide
backbone for a stabilizing n * interaction in the trans conformation .
this second result contrasts with
earlier reports from schweizer s group that showed both -
and -galactosylation of ac - hyp - nhme or ac - hyp - ome to have essentially no
impact on the thermodynamics or kinetics of the cis trans equilibrium . to investigate the mechanism behind the differences
in equilibrium
constants for compounds 15 , kinetics
of the prolyl peptide bond isomerization were studied by magnetization
transfer nmr experiments .
experiments were performed
at elevated temperatures ( 6080 c ) because at lower temperatures
the rates are too slow to be determined by this method .
related experiments
have been performed in unbuffered d2o , and reimer
et al . demonstrated that for end - capped pentapeptide ac - ala - thr - pro - ala - lys - nh2 , the rate of cis
trans isomerization was independent of ph across the 1.810.8 range
and a variety of temperatures .
this was
shown to be a general phenomenon across a series of pentapeptides
without ionizable side chains .
the cifit program was used to estimate the rate constants for the trans cis process . the reverse
reaction rates ( cis trans )
data were fitted according to the eyring equation to afford the activation energy data presented in table 3 .
the italic values are data determined
in the current work ; data below those in italics come from the literature for comparative purposes .
/ c and ktc . upon hydroxylation there
is a decrease in the rate of conversion
of trans cis 20%
in the case of ac - pro - nhme ( 8 vs 7 ) and 40% at the dipeptide level ( 2 vs 1 ) .
the cis trans rates do not follow the same trend ; there is a 10%
decrease in rate from 7 to 8 , but a 80% increase from 1 to 2 .
this accounts for the more pronounced increase
in kt / c in the dipeptide series .
indeed , larive and rabenstein also concluded
that large kt / c values for prolyl peptide bond isomerization in oxytocin and
arginine vasopressin were also due to an increase in the rate
of the forward reaction , rather than an inherent increase in the stability
of the trans conformation , relative to smaller molecules . with the increase in electronegativity of the
4r substituent , there is presumably an increase in
the sp - character and degree of pyramidalization of the
pyrrolidine nitrogen that facilitates rotation about the c
n
amide bond . as originally demonstrated by fischer et al . , a hydrogen bonding interaction between the pyramidalized
nitrogen and the nh of the residue c - terminal to pro ( mimicked in our case by the nhme )
helps to lower the energy of the transition state .
model compounds
in which this amide is substituted for by an ionizable carboxylate
or an ester can not emulate this feature of the peptide backbone . in the proline methyl amides 79 ,
the free energy barriers to rotation about the amide bond are dominated
by enthalpic factors . while entropy values are positive and close
to zero for these amino acid derivatives , significant negative entropies
of activation are observed for compounds 1 , 2 , and 5 .
this is generally true of larger peptides and reflects a higher degree of organization
in the transition state for an extended peptide molecule .
compound 1 shows very different
activation enthalpy and entropy contributions , relative to compounds 2 and 4 .
this must be attributable to the influence
of the electron - withdrawing substituent on the energy and degree of
organization of the transition state . in the case of glycodipeptide 4
there was no cis / trans pair of resonances in the h nmr spectrum with adequate
resolution for the signal of
one conformation to be selectively inverted without also inverting
the signal of the other conformation .
shi et al . have previously acknowledged
that not all peptides are amenable to rate determination in this manner .
lubell and co - workers have used inversion of
the c trans signal in c nmr to
measure rates of trans cis isomerization . in the present case ,
a single
set of resonances was observed for compound 4 , even at
70 c .
these experimental facts precluded magnetization transfer
experiments that would have given insight into the impact of glycosylation
on cis
the importance of n - acetyl groups of sugars in
hydrogen bonding and peptide conformation has been commented on by
wong and co - workers and also by live
et al .
the differences in kt / c , ktc , and kct between compound 5 , bearing a glcnac residue , and the gal derivative 9 reported by schweizer and co - workers are almost within experimental error .
the only notable
difference is in the entropies of activation : the glcnac residue in 5 seems to incur a higher degree of order in the transition
state for peptide bond isomerization than the gal residue in 9 . on the basis of goesy experiments conducted for compound 9 ,
owens et al . described a conformation in which the hydrophobic
face of the galactose residue sits over the top of the pyrrolidine
ring ( figure 3 ) .
there were few crosspeaks in the noesy spectrum of compound 5 , in which gal is substituted by glcnac .
weak crosspeaks
potentially support a conformation similar to that of 9 but are ambiguous due to severe peak overlap in the 3.54.0
ppm region of the h nmr spectrum .
a more defined conformation
for dipeptide 4 was discernible , based on noesy crosspeaks
summarized in figure 3 .
one - dimensional goesy
experiments supported these conclusions ( see supporting
information ) .
as depicted in figure 3 , it appears that the strong preference for the c-exo pyrrolidine ring and trans peptide
bond ( with alignment for the n * backbone interaction )
renders the threonine side chain partially over the pyrrolidine ring ,
pushing the sugar residue away .
to better understand
the role of the threonine residue , we considered
key chemical shift and coupling constant data for this residue . in
compounds 1 , 2 , and 4
, the
thr c and c chemical shifts did not show much variation :
57.157.2 and 67.168.8 ppm , respectively .
these are
somewhat upfield of statistical average values , as expected
when the ( i + 1 ) residue is pro .
amide proton ( vide infra ) and h chemical shifts
likewise showed little change upon c substitution : 8.158.26
and 4.584.61 ppm , respectively .
these values are closer to
those observed for random coil peptides than for -helix or
-sheet . motifs .
there was an increase in jnh , h across the
series at 295 k : 4.8 hz ( 1 ) , 6.9 hz ( 2 ) ,
and 7.8 hz ( 4 ) reflecting a change in the theta ( )
dihedral angle .
h nmr spectra were acquired in 90%
h2o ,
10% d2o at neutral ph .
the c - terminal methyl amide ( nhch3 ) gave rise to a broad signal with a similar chemical
shift in all compounds .
the glcnhac amide in compounds 4 and 5 showed a typical j coupling contant of 910 hz to h2 .
the acnhthr amide ( in compounds 1 , 2 , and 4 ) displayed a chemical shift
of 8.18.2 ppm . a significant difference in chemical
shift
was observed for the h that is trans to h in compounds 4 ( 4.17 ppm ) and 5 ( 3.79 ppm ) .
this reflects the relatively deshielded
environment in compound 4 where the polar thr side chain
is in close proximity , compared to compound 5 where h
is shielded by the hydrophobic face of the sugar . in all cases ,
variable
temperature experiments showed typical temperature dependence for
non - hydrogen bonded amides ( < 4 ppb k ) .
thus , the strong conformational preferences appear
to be due to steric and stereoelectronic effects and thereby provide
a true baseline for moving forward to study larger peptides .
reorganization of the pivotal pro region of skp1
is a recurring theme during interactions with f - box proteins .
recent
cd and saxs studies show that the secondary structure content of free
skp1 of dictyostelium is sensitive to its glycosylation
status which correlates with binding to a model f - box protein .
crystal structures have demonstrated a well - folded
state for skp1 complexed with f - box proteins in other organisms .
the equivalent of pro is highly conserved throughout
phylogeny except for chordate animals . even in organisms with multiple
skp1 genes , at least one copy of the pro - containing skp1 is retained .
.
even in skp1 proteins where the equivalent of pro is
substituted by another amino acid , the theme of reorganization persists .
a study by tan et al . of ocp2 ( an orthologue of skp1 from the organ
of corti ) concluded that binding to ocp1 ( bearing an f - box motif )
is accompanied by a substantial degree of refolding .
the c - terminal region is alternatively
folded in a loop in one complex .
thus , a picture is emerging that skp1 exists as an ensemble of
conformations whose suitability to dock with f - box protein partners
is under environmental regulation via effects of post - translational
modifications to skp1 .
indeed , zondlo and co - workers have recently
uncovered the role of threonine / serine phosphorylation and glcnac
attachment in mediating neighboring secondary structure .
the model we propose herein is analogous to the mechanism by which
the skp1 homologue elongin c selects its binding partners in a related
e3 polyubiquitin ligase and may allow
for regulation of the rate or selectivity of polyubiquitination of
target proteins with impact on development .
milner - white et al . observed
that pro residues at the n - terminus of -helices always adopt trans prolyl peptide bonds and demonstrate a strong preference
for the c-exo pyrrolidine conformation . the post - translational modifications to pro enhance preferences for these conformational attributes
and thereby offer an attractive mechanism to trigger global changes
in skp1 conformation and deserve further mechanistic studies . | ### Summary:
: prolyl
hydroxylation and subsequent glycosylation of the e3scf ubiquitin ligase subunit skp1 affects its conformation
and its interaction with f - box proteins and , ultimately , o2-sensing in the organism . taking a reductionist approach to understand
the molecular basis for these effects , a series of end - capped thr - pro
dipeptides was synthesized , tracking the sequential post - translational
modifications that occur in the protein .
the conformation of the pyrrolidine
ring in each compound was gauged via coupling constants ( 3jh,h ) and the electronegativity of the c-substituents
by chemical shifts ( 13c ) .
the equilibrium between the cis
trans conformations about the
central prolyl peptide bond was investigated by integration of signals
corresponding to the two species in the 1h nmr spectra
over a range of temperatures .
these studies revealed an increasing
preference for the trans - conformation in the order
pro < hyp < [ -(1,4)glcnac]hyp .
rates for the forward
and reverse reactions , determined by magnetization transfer experiments ,
demonstrated a reduced rate for the trans - to - cis conversion and a significant increase in the cis - to - trans conversion upon hydroxylation
of the proline residue in the dipeptide .
noe experiments suggest that
the thr side chain pushes the sugar away from the pyrrolidine ring .
these effects , which depended on the presence of the n - terminal thr residue , offer a mechanism to explain altered properties
of the corresponding full - length proteins . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: mechanical failure of femoral stem after total hip arthroplasty is well reported in the literature .
albeit being rare , with the prevalence of 0.2311% , the consequences can be devastating to the patients .
three - dimensional analysis dictates highest stress concentrations are around the lateral aspect of the middle third of the femoral stem .
femoral stem failure can be broadly categorised to patient - specific factors , technical issues or implant related factors . in revision hip arthroplasty ,
the safe extraction of retained fractured components remains a challenging prospect as it can be extremely demanding and potentially detrimental to the remaining host bone .
therefore , many approaches have been described to address this complex issue before hip reconstruction . among those ,
the technique of drilling a hole in the exposed proximal part of retained fractured femoral stem and attaching a threaded extraction device , or sophisticated surface undercutting and an extraction device wedged in to facilitate extraction .
removal of cemented well fixed broken stem can be also achieved by a femoral trephine technique , femoral cortical window technique , extended femoral osteotomy ( eto ) procedure and retrograde nail impaction via the knee joint .
we describe a modified technique for extraction of well - fixed cemented fractured femoral stem .
a 52-year - old female had bilateral sequential total hip replacement for idiopathic avascular necrosis of femoral heads .
the right hip was cemented charnley elite ( de puy international , leeds , uk ) and the left side was uncemented jri ha coated ( joint replacement institution , sheffield , uk ) total hip arthroplasty . both hip arthroplasties were uneventful . however , 10 years following right total hip replacement , patient started to experience a gradually worsening pain in proximal right thigh with no history of trauma .
the fractured stem was approached by creating a small , longitudinal , posterior femoral cortical window measures 1 cm 2 cm just below the level of fracture of femoral stem . through this window , tungsten carbide drill bit ( synthes , west chester , pa , usa )
is employed to create a crater on the proximal end of residual stem posteriorly ( fig .
once achieved , a charnley pin is used to disimpact the residual stem through the crater by controlled retrograde orthopaedic mallet blows till the stem is extracted .
once stem removed , the cortical window is re - positioned and two - cable ready system ( zimmer , warsaw , in , usa ) applied to secure the cortical window .
the cement mantle in this technique is preserved and cement - in - cement technique was performed to achieve femoral stem revision . a small developmental dysplasia of hip ( ddh ) exeter stem was cemented in utilising the cement- in - cement technique ( fig .
follow up , the patient was independently mobile with pain free hip and good range of motion .
oxford hip score was 47 and harris hip score was 91 . a 74-year - old male patient with bilateral total hip arthroplasties .
the last two were for fractured femoral stems . the last revision was in 2004 years and ran a smooth post operative course . in december 2012 , this patient presented acutely with atraumatic crescendo pain in his right hip .
this patient sustained preoperative myocardial infarction and the cardiologist advised strongly against discontinuing clopidogrel to maintain the patency of his cardiac stents .
the decision was made to revise only the fractured femoral components as full hip revision arthroplasty could have been detrimental to his health .
this is because of his multiple co - morbidities and high american society of anaesthesia score ( asa ) of 4 .
patient underwent single stage revision surgery where the fractured femoral stem was extracted using this modified extraction technique .
the acetabular component was retained and supplemented with a posterior lip augmentation device ( plad ) to secure the hip from any potential future dislocation . at 12 months
follow up , patient denies any hip pain and has a stable range of motion .
radiographs showed evidence of osseus incorporation of cortical window in both patients ( fig . 5 ) .
a 52-year - old female had bilateral sequential total hip replacement for idiopathic avascular necrosis of femoral heads .
the right hip was cemented charnley elite ( de puy international , leeds , uk ) and the left side was uncemented jri ha coated ( joint replacement institution , sheffield , uk ) total hip arthroplasty . both hip arthroplasties were uneventful . however , 10 years following right total hip replacement , patient started to experience a gradually worsening pain in proximal right thigh with no history of trauma .
the fractured stem was approached by creating a small , longitudinal , posterior femoral cortical window measures 1 cm 2 cm just below the level of fracture of femoral stem . through this window , tungsten carbide drill bit ( synthes , west chester , pa , usa )
is employed to create a crater on the proximal end of residual stem posteriorly ( fig .
once achieved , a charnley pin is used to disimpact the residual stem through the crater by controlled retrograde orthopaedic mallet blows till the stem is extracted .
once stem removed , the cortical window is re - positioned and two - cable ready system ( zimmer , warsaw , in , usa ) applied to secure the cortical window .
the cement mantle in this technique is preserved and cement - in - cement technique was performed to achieve femoral stem revision . a small developmental dysplasia of hip ( ddh ) exeter stem was cemented in utilising the cement- in - cement technique ( fig .
follow up , the patient was independently mobile with pain free hip and good range of motion .
the last revision was in 2004 years and ran a smooth post operative course . in december 2012 , this patient presented acutely with atraumatic crescendo pain in his right hip .
this patient sustained preoperative myocardial infarction and the cardiologist advised strongly against discontinuing clopidogrel to maintain the patency of his cardiac stents .
the decision was made to revise only the fractured femoral components as full hip revision arthroplasty could have been detrimental to his health .
this is because of his multiple co - morbidities and high american society of anaesthesia score ( asa ) of 4 .
patient underwent single stage revision surgery where the fractured femoral stem was extracted using this modified extraction technique .
the acetabular component was retained and supplemented with a posterior lip augmentation device ( plad ) to secure the hip from any potential future dislocation . at 12 months
follow up , patient denies any hip pain and has a stable range of motion .
our proposed method exploits the concept of small cortical window just distal to the proximal part of the broken stem .
although utilising the cortical window is not a novel technique , the modification described herein utilising simple instrumentations , using a narrow osteotome , a small rectangular window 1 cm 2 cm is created along the long axis of the proximal femur posteriorly .
the other modification includes , after removal of cortical window , a tungsten drill bit is utilised to drill and create a crater the posterior aspect of the well fixed distal broken stem .
a charnley pin retractor is used to disimpact the femoral stem by careful and controlled retrograde orthopaedic mallet impaction till the successful extraction is achieved .
after stem extraction , the cortical window is keyed - in and secured with cable ready system . in morland 's technique ,
the cortical window has to be grafted due to cortical destruction using a high speed burr .
the cortical window in our method is slightly bigger in dimension ( 1 cm 2 cm in comparison to 0.4 cm 1 cm in morland 's method ) .
we believe this is necessary to prevent damage to the rest of femoral bone during drilling and preserving cement mantle during femoral component extraction .
this cortical bone window can be readily sealed and secured with cables . in our method ,
we favour this technique as slot osteotomy in femoral component / synthetic bone construct offer significantly superior stiffness when compared to ( eto ) constructs . in our case
series , the first patient had her femoral stem revised to small ddh stem with cement in cement technique . by creating a proximal femoral window , a standard length primary stem can span the window without risking weakening of the femur .
femora windowed distal to tip of fractured stem , to aid retrograde tapping , risk stress risers and authors recommend long revision stem to traverse cortical window to prevent periprosthetic fractures .
therefore , proximal cortical window was performed because the fracture of femoral stem happened at the proximal one third ; this allowed safe bypassing the cortical window without running the risk of the cortical window acting as a stress riser .
therefore , proximal cortical window and the existing cement mantle were sufficient to utilise and offer the patient a primary rather than revision implant .
the second patient was a high anaesthetic risk patient who was in significant hip pain and limited mobility due to a fracture of a long revision femoral stem and with evident proximal femoral bone loss ( paprosky iii - b ) .
a lengthy single stage revision of both acetabular and femoral components would invariably be associated with high perioperative morbidity and mortality .
such symptomatic patient requires short procedure , albeit the revised long stem may re - fracture with time because of poor proximal femoral bony stock .
therefore , it was mandatory to implant a long revision femoral stem to address the non supportive femoral metaphysis and the limited diaphysial fixation . in both patients ,
the preservation of femoral stem cement mantle remains an attractive option as removing bone cement can be detrimental to host bone and can culminate in fractures or perforation .
our modified technique offers a simple and controlled method in extracting a well fixed fractured cemented femoral stem .
it has the advantage of retaining the cement mantle with subsequent good seal of the femoral cortical window secured with cable ready system .
furthermore , tungsten carbide drill bit and charnley pin retractor are relatively readily available to aid the extraction of the broken stem
. finally , it yields the option of implanting a standard femoral stem and obviates the need for bypassing the cortical window with long revision femoral component .
the removal of well - fixed fractured femoral component can be extremely demanding and potentially detrimental to the remaining host bone .
the sliding cortical window technique utilising tungsten carbide drill and charnley pin retractor is technically easy and most importantly ; preserves host bone stock with cement - in - cement revision hip arthroplasty .
we believe this technique can be added to the armamentarium of revision hip surgeon when faced with the challenge of extracting a fracture cemented femoral stem .
written informed consent was obtained from the patient for publication of this case report and accompanying images .
a copy of the written consent is available for review by the editor - in - chief of this journal on request
the two senior authors supervised , critically revised the article and were the operators in the surgical procedures illustrated . | ### Summary:
: introductionthe removal of well - fixed broken femoral component and cement mantle can be extremely demanding , time consuming and potentially damaging to the host bone .
different methods have been described to extract broken femoral stem yet this remains one of the most challenging prospect to the revision hip surgeon.presentation of casethe authors present two cases underwent a modified sliding cortical window technique utilising a tungsten carbide drill , charnley pin retractor and an orthopaedic mallet to aid extraction of a fractured cemented femoral stem in revision total hip arthroplasty.discussionthe modified technique offers a simple and controlled method in extracting a well fixed fractured cemented femoral stem .
it has the advantage of retaining the cement mantle with subsequent good seal of the femoral cortical window secured with cable ready system .
furthermore , tungsten carbide drill bit and charnley pin retractor are relatively readily available to aid the extraction of the broken stem . finally , it yields the option of implanting a standard femoral stem and obviates the need for bypassing the cortical window with long revision femoral component.conclusionfractured femoral stem is a rare yet a complex and very demanding prospect to both patients and hip surgeons .
the sliding cortical window technique utilising tungsten carbide drill and charnley pin retractor is technically easy and most importantly ; preserves host bone stock with cement - in - cement revision hip arthroplasty .
we believe this technique can be added to the armamentarium of revision hip surgeon when faced with the challenge of extracting a fractured cemented femoral stem . |
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: calorimetric studies
of molecular recognition provide not only
the free energy of binding but also the breakdown of the free energy
into its entropic and enthalpic components .
such breakdowns promise insight into the molecular driving forces
for binding and hence guidance in the design of supramolecular
systems and of high - affinity ligands for targeted proteins .
for example , there is still no generally accepted explanation
for the widespread phenomenon of entropy enthalpy compensation , and although cyclization of small molecule ligands may be expected
to reduce the entropy cost of binding , this is by no means consistently
observed .
host guest systems , which have significantly
fewer degrees of freedom than protein ligand systems , yet still
exemplify many of the aforementioned paradoxes , are informative and tractable models of molecular recognition
with readily available isothermal titration calorimetry ( itc ) data .
however , itc data , regardless of system size , still lack a detailed
decomposition of the physical interactions responsible for the measured
thermodynamic quantities and therefore can not yield full explanations
of the binding thermodynamics . here , we propose the use of atomistic
molecular simulations on
small host guests systems as a first step toward providing detailed
insight into the molecular determinants of binding thermodynamics
and thus complementing experimental calorimetry .
previously , calculating
well - converged binding enthalpies has proved challenging , and the low precision of the results has inhibited rigorous comparisons
between calculation and experiment . in addition , most computational
methods for calculating binding enthalpies , such as by calculating
the entropy from the temperature derivative of the binding free energy
and subtracting it from the free energy to obtain the enthalpy , do not directly provide the decompositions of the binding enthalpy
into molecular ( e.g. , solvent
solute ,
or solute solute ) or force - field component contributions that
could provide insight into the molecular basis for the changes in
enthalpy associated with molecular recognition .
the present
study takes advantage of the dramatic speedup of molecular simulations afforded by graphical processor units ( gpus )
to compute the binding enthalpies of the host cucurbituril ( cb7 )
with five high - affinity aliphatic guests and three relatively low
affinity aromatic guests , with numerical precision equal to or better
than the reported error of the associated itc data .
the calculations
correlate well with experiment and , in particular , replicate the experimental
observation that the aliphatic guests bind with substantially more
favorable enthalpy changes than the aromatics .
energy decomposition
analysis indicates that the aromatic guests are less enthalpically
favored than the aliphatic guests due primarily to their poorer steric
fit into the circular structure of cb7 .
more broadly , the calculations
indicate that the binding enthalpies are delicate balances of much
larger energetic shifts in solute solute , solute
dispersion forces emerge
as a major contributor , despite the polar nature of the host and most
of the guests .
we used microsecond time
scale molecular dynamics simulations ,
with explicit solvent comprising water and dissolved ions , to compute
the binding enthalpies for the synthetic host cb7 with eight guest
molecules ( figure 1 ) .
the experimental binding
enthalpies , h , correlate with the guests
structural scaffolds : the most exothermic are the adamantanes ( a1 ,
a2 ) , followed by the bicyclo[2.2.2]octanes
( b2 , b5 , b11 ) , the benzo - bis(imidazoles )
( g8 , g9 ) , and finally methylviologen .
the following subsections compare the computations
with experiment and use energy decomposition analysis to study the
physical determinants of these host guest binding enthalpies .
structures
of the host cb7 ( left ) and eight guest molecules for
which binding enthalpies were computed here .
binding enthalpies
computed with the tip3p water model ( table 1 ) correlate well with experiment ( figure 2 ) : linear regression analysis yields a correlation
coefficient r = 0.91 0.01 , a slope near unity
( 1.15 0.02 ) , and a small y - intercept ( 1.12
0.21 ) .
there is a modest tendency to overestimate the binding
enthalpies , indicated by a mean signed error ( mse ) of 2.97
0.09 kcal / mol across all eight guests .
the calculations furthermore
capture the physical interactions in the systems well enough to replicate
the ranking of enthalpies according to the guests structural
features , as indicated by the color - coding of data points in figure 2 .
matched simulations using the tip4p - ew water model , instead of tip3p , also correlate
well with experiment ( r = 0.87 0.01 , slope
1.03 0.02 , y - intercept 6.35
0.24 ) but further overestimate the measured affinities ( mse 6.75
0.11 kcal / mol ) .
therefore , the energy decomposition studies
that follow focus on the tip3p results . however , the trends discussed
here are consistent for tip4p - ew , as detailed in the si . in assessing these results , it is essential to consider
the uncertainties associated with both the computational and experimental
results . as shown in table 1 ,
the reported
experimental uncertainties of the mean range between 0.1 and 0.3 kcal / mol ,
and the numerical uncertainties of the computed enthalpies , based
on blocking analysis ( see methods and si ) , are commensurate , at 0.2 to 0.3 kcal / mol .
( note , we report standard deviations of the mean as our measure of
computational uncertainty .
thus , to compare directly with experiment ,
we converted all previously reported experimental uncertainty values
into standard deviations of the mean by dividing by the square root
of the number of replicates . ) the high precision of these calculations
is supported by the fact that the correlation times estimated by blocking
and statistical inefficiency analysis are at most 1.0 ps ( see si ) ; therefore , each microsecond - duration simulation
provided a minimum of 500 000 independent estimates
of the mean energy .
in addition , geometric analysis ( see si ) shows that the guests thoroughly sample rotations
about the symmetry axis of the cb7 host ; and although the overall
orientation of the guests within the host ( head in
versus head out ) does not change during the simulations ,
sampling such reversals is not required to achieve convergence , because
both orientations are chemically equivalent , due to the symmetry of
cb7 . the small uncertainties in the computational and experimental
data lead to the correspondingly small uncertainties in the regression
parameters reported above , based on bootstrap resampling of the experimental
and computed enthalpies ( see methods ) .
we also determined the best agreement that could possibly be obtained
with calculations at the present level of numerical precision , by
imagining calculations which correctly yield the experimental binding
enthalpies , but still with a numerical uncertainty of 0.20.3
kcal / mol ( table 1 ) .
bootstrap resampling of
data from this imagined computational study , and from the experimental
data set with its own uncertainties , yields r = 1.00
0.00 , slope 1.00 0.02 , y - intercept
0.01 0.23 kcal / mol , and mse 0.00 0.10 kcal / mol .
the high quality of these idealized statistics suggest that the experimental
and numerical precision are good enough that deficiencies in the simulation
force field now represent the only obstacle to obtaining clear - cut
agreement with experiment .
comparison of binding enthalpies ( kcal / mol ) from experiment ( expt )
and simulation with tip3p water model ( calc ) , for cb7 with eight guest
molecules .
green diamonds :
bicyclo[2.2.2]octane derivatives : b2 , b5 . orange triangles : g8 , g9 .
the present
computational methodology enables informative decompositions of the
binding enthalpy into energy components , and these components can
furthermore be correlated with conformational preferences observed
in the simulations . in this section , we use these capabilities to
seek insight into the determinants of the observed binding enthalpies
for the eight cucurbituril guest systems .
val : contribution from changes in bond - stretch ,
angle - bend , and dihedral terms .
nclose : change on binding in the number of atoms ,
solute or solvent , within 4.25 of any atom of the host and
guest .
table 2 provides a breakdown
of binding enthalpies for all eight guests , computed with the tip3p
water model , into three contributions : one from the net change in
the lennard - jones force field term , which primarily models van der
waals forces ; one from the net change in coulombic electrostatic interactions ;
and one from changes in valence terms , which comprise bond - stretch ,
bond - angle , and dihedral terms .
representative conformation from simulation
of cb7 host containing
a molecule of tris buffer ( mvn / tris ) .
it is immediately noticeable that the lennard - jones term
is consistently
favorable ( negative ) , except in the case of the methylviologen ( mvn / tris ) .
the unique feature of the mvn system is the use of an organic buffer ,
tris , which was included not only in the experiments but also in these
initial methylviologen simulations ( see methods ) .
it was therefore of interest to rerun the enthalpy calculation
for mvn without tris .
the resulting binding enthalpy is more favorable
by 2.6 kcal / mol , and the lennard - jones contribution is now
favorable , similar to that of the other guests ; see mvn / notris in
table 2 .
examination of the simulations in
the presence of tris reveals that this cationic compound takes up
residence in the binding cavity of the free cb7 host ( figure 3 ) and is necessarily displaced when methylviologen
binds .
the consequent loss of favorable lennard - jones interactions
between the tris molecule and the host helps balance the gain in lennard - jones
interactions between the guest and host , which is further discussed
below . unlike the lennard - jones contribution , which is uniformly
favorable
in the absence of tris , the electrostatic contribution varies in sign
and tends to be smaller in magnitude ( table 2 ) .
interestingly , when the tip3p water model is used , the electrostatic
contribution is anticorrelated with the charge of the guest , especially
if the mvn / tris and g8 data are removed ( see table 2 ) .
however , there is little correlation between the electrostatic
component and the charge of the guest when the tip4p - ew water model
is used ( see si , table s2 ) .
further decomposition
of the electrostatic contribution into solute and solvent parts reveals
that its small and variable character results from systematic compensation
of solute solute interactions by changes in solvent electrostatics .
thus , as shown in the left panel of figure 4 , the net solvent contribution to the electrostatic contribution
( green symbols ) almost exactly cancels the strongly favorable solute solute
contributions ( x - axis ) .
indeed , a linear regression
fit gives y = 1.04x
6.52 kcal / mol , with r = 1.00 .
decomposition of the
solvent contribution itself reveals strongly unfavorable losses in
solute solvent electrostatics on binding ( blue symbols ; y = 1.96x + 5.93 kcal / mol , r = 1.00 ) and favorable gains in solvent
solvent
interactions ( red symbols ; y = 0.92x 12.45 , r = 0.98 ) .
thus , although the host guest
electrostatic interactions range to almost 180 kcal / mol ( figure 4 , left ) , they are almost perfectly balanced by compensating
interactions involving the solvent : for every 1 kcal / mol of
solute solute electrostatic energy , there is a penalty of about
+ 2 kcal / mol in solute
solvent energy , and a gain of about 1
kcal / mol of solvent solvent energy .
these powerful trends are
consistent with the well - known concept that forming a new hydrogen - bond
between two solutes in water requires sacrificing two solute - water
hydrogen bonds , but also leads to the formation of one new water water
hydrogen bond between the released water molecules .
such strong
solvent compensation is not observed for the lennard - jones
contribution ( figure 4 , right ) .
although the
net solvent contributions to the lennard - jones term are unfavorable
by roughly 25 kcal / mol , they do not fully cancel the solute
solute
contribution , except in the special case of mvn / tris ( unfilled , green
circle ) , where the solvent includes a molecule of tris .
moreover ,
there is only a weak trend for the net solvent contribution to become
more unfavorable as the solute solute lennard - jones interaction
becomes more favorable .
solvent
interactions that were sacrificed ( blue symbols ) , and little solvent solvent
lennard - jones energy is recovered by water release ( red symbols ) .
as a consequence , much of the favorable solute
solute interaction
remains in effect , leading to the favorable overall lennard - jones
interactions listed in table 2 .
guest )
lennard - jones interactions formed on binding come at a relatively
modest cost in solvent lennard - jones interactions may be attributed
to the high packing density of atoms in the host
the mesh of covalent bonds within the
host and guest molecules means that there are more non - hydrogen atoms
per unit volume than in liquid water , with its comparatively long
interoxygen distances . as a consequence ,
binding increases the number
of short - ranged ( < 4.25 ) atom atom interactions ( nclose in table 2 ) , except
for mvn / tris , and hence also increases the number of favorable lennard - jones
interactions .
this interpretation is supported by the correlation
( r = 0.98 ) between nclose and the net lennard - jones contribution to the binding
enthalpy .
role of solvent in electrostatic and lennard - jones interaction
energies ( kcal / mol ) .
solid green : net solvent contribution
( solute solvent + solvent solvent ) .
solute interaction energy
is depicted as a dashed line , with a slope of 1 .
the measured binding
enthalpies of the three aromatic guests ( g8 , g9 , and methylviologen )
are notably less favorable than those of the five aliphatic guests
( a1 , a2 , b2 , b5 , and b11 ) .
the calculations capture this experimental
trend ( table 1 and figure 2 ) and may be analyzed to seek a possible explanation for it .
because all three aromatic guests are dications , we compare them with
the one cationic aliphatic guest , b5 .
although one might expect
the aromatic , and hence relatively polarizable , methylviologen guest
to form more favorable dispersion interactions with the cb7 host ,
relative to the aliphatic b5 , its overall lennard - jones contribution
is far less favorable , even when tris is not included in the simulations
( table 2 ) .
this difference , along with more
modest electrostatic and valence contributions , accounts for the less
favorable binding overall enthalpy computed for mvn / notris relative
to b5 .
these differences are rationalized , at least in part , by comparison
of representative structures of b5 and methylviologen complexed with
cb7 ( figure 5 ) . in particular , whereas the
round bicyclo[2.2.2]octane core of b5 nicely fills the round cavity
of cb7 , the relatively flat core of methylviologen does not fit well .
the unfilled gaps between this guest and the host correlate with the
less favorable lennard - jones term , and the distortion of the normally
circular host to an elliptical shape accounts for the valence penalty .
in addition the net electrostatic contribution to the binding enthalpy
of methylviologen is not favorable , when tris is absent .
this may
reflect a combination of partial desolvation of its relatively delocalized
positive charge , and its inability to donate hydrogen bonds to the
carbonyl groups at the portal of cb7 .
interestingly , the pattern
is somewhat different for the other
two aromatic guests , g8 and g9 .
these maintain strongly favorable
lennard - jones interactions with the host , despite their flattened
shape , apparently because their methyl groups , absent in methylviologen ,
tuck neatly into equatorial grooves of the distorted cb7 host ( figure 5 ) .
in addition , the more elongated shape adopted
by cb7 when g8 and g9 are bound may allow closer packing along the
flat faces of these guests . however , the enthalpy decompositions of
these two guests resemble methylviologen in the sense that they also
do not have favorable net electrostatic contributions .
representative conformations
from the most probable cluster based
on rmsd of the complexes of the dicationic
guests b5 , g8 , g9 , and mvn ( space - filling representation ) bound to
cb7 ( solvent - accessible surface representation ) , each shown from three
viewpoints . rendered with the program vmd .
the attractive
component of the lennard - jones energy term , which
accounts primarily for dispersion forces , contributes strongly to
the computed binding enthalpies in all cases studied here , except
in the special case where the organic buffer tris is present in solution .
the conclusion that dispersion interactions contribute strongly and
consistently to the binding enthalpies may appear contrary to an elegant
experimental study , which suggested that
dispersion interactions contribute minimally to the folding free energy
of a molecular torsion balance in various
solvents .
solute
dispersion interactions formed upon folding are closely balanced by
simultaneous unfavorable losses in solute solvent interactions .
in the present calculations , too , the net dispersion interaction is
a balance of solute solute and solvent terms , but there is
only partial cancellation by solvent , so the net dispersion contribution
is strongly favorable .
this result is explained by the increased number
of close atom pairs for the complex versus the free host and guest ,
which in turn traces to the high packing density of the polycyclic
host and guest molecules , relative to liquid water .
the rigidity and
the close fit of these complexes also presumably play a role .
in contrast ,
for the torsion balance study , the interacting species in the torsion
balance study are hexyl chains , which are much more flexible and less
densely packed than the polycyclic molecules considered here .
the
relatively poor packing of these hexyl chains may well account for
the modest contribution of dispersion forces to their association .
another probing study used the correlation
of a spectroscopic feature with solvent polarizability to suggest
that the binding site of cb7 is of especially low polarizability ,
and argued on this basis that dispersion forces , which are closely
related to electronic polarizability , play little role in the binding
of guests by cb7 .
however , because the net contribution of dispersion
interactions to the binding enthalpy is a balance between newly formed
host guest interactions and lost solute water interactions ,
the net effect of a low polarizability binding cavity is hard to predict .
put differently , even if the cb7 host forms only weak dispersion interactions
with the molecules in its binding cavity , it also loses only weak
dispersion interactions with the water ejected from the cavity upon
binding . as a consequence ,
a robust trend in the present experimental
data is that the aromatic
guests bind less enthalpically than the aliphatic ones ; recent results
for the guest berberine fit this pattern as well .
decomposition of the binding enthalpies into lennard - jones ,
electrostatic , and valence contributions , along with inspection of
the structures of the complexes , suggests that this difference can
be explained primarily by considerations of shape complementarity
and electrostatics .
thus , the rounded bicyclooctane and adamantane
cores of the aliphatic guests fit well into the preferred circular
shape of the host , while positioning their polar groups outside the
binding cavity and forming hydrogen bonds with host carbonyls . in
contrast
, the flatter aromatics distort the host and pay large electrostatic
desolvation penalties that are not outweighed by favorable host guest
electrostatic interactions .
the tip3p water model yields clearly more accurate
results than tip4p - ew in the present application , even though the
two models provide similarly accurate small molecule hydration free
energies .
in addition , tip4p - ew more
faithfully reproduces various water properties , such as the oxygen oxygen
radial distribution function of neat water , the preferred geometries of gas - phase water clusters , the hydration enthalpy of methane , and the hydration enthalpies of both hydrophobic
and polar amino acid side chain analogs .
the fact that tip4p - ew yields stronger electrostatic contributions
to the binding enthalpies than tip3p appears consistent with the fact
that tip4p - ew water has a room temperature dielectric constant lower
than that of tip3p : 62.9 versus 96.9 .
however , more subtle factors may also contribute
to the differences in results from these two models .
for example ,
they may ascribe different thermodynamic properties to the water in
the binding cavity of the host molecule .
whatever the explanation , the present results strongly suggest that
a water model optimized for one type of application , such as replicating
the properties of neat water , may not be optimal for another application ,
such as the study of host guest binding .
it would appear that
water models should tested against actual binding data , if they are
to be used in applications where binding is of central interest , such
as computer - aided drug design .
more generally , the fact that
tightly converged host guest binding enthalpies can now be
computed efficiently on a commodity computer means that binding enthalpies
can be added to the experimental data set for testing and improving
simulation force fields .
the set of observables currently used for
this purpose primarily comprises small molecule hydration free energies and properties of pure liquids , such as densities
and heats of vaporization .
although this data set is valuable , it
does not probe many of the noncovalent interactions important in drug
discovery , and as noted above , it does not test the ability of water
models to correctly handle confined environments , such as protein
binding sites .
buff approaches , and approaches based on the conformational preferences
of proteins and nucleic acids usefully examine the critical balance
between solute solvent and solute solute interactions
but are still limited in chemical scope and do not address the problem
of confined water . experimentally and computationally tractable host
guest
systems offer new possibilities to probe the accuracy with which force
fields account for the interactions of varied functional groups and
for the thermodynamics of water in concave binding sites .
although there are
a number of computational techniques for estimating enthalpy changes , obtaining tightly converged binding
enthalpies from simulations has been technically challenging .
guest
systems , which are now readily achievable with gpu technology , can provide computed binding enthalpies with a precision comparable
to the corresponding experimental uncertainties .
we used the direct
approach , which involves simulations only of the system s initial
and final states .
most other enthalpy methods require multiple simulations
at stages along a pathway leading from the initial to the final state .
for example , the finite difference ( fd ) method uses a pathway approach
to compute the binding free energy at multiple temperatures , and then
estimates the binding entropy , and hence enthalpy , from the temperature
derivative of the free energy . which of the various methods will be
most numerically efficient likely depends upon the nature of the system
being simulated . for example
, the fd method may be preferable for
large systems , where large energy fluctuations slow convergence of
the direct method .
on the other hand , the numerical properties of
the direct method may be preferable for systems where the change in
enthalpy is large , and its technical simplicity also is appealing .
it should also be emphasized that the direct enthalpy method has the
particular advantage of providing informative decompositions of the
binding enthalpy , which may furthermore be connected with conformational
preferences , as illustrated by the present study .
thus ,
the present study establishes that detailed atomistic simulations
can provide tightly converged estimates of noncovalent binding enthalpies
for molecular systems in aqueous solution , and can be used to seek
explanations for calorimetric characterizations of binding .
this is
an important direction , because calorimetric data are often puzzling
or even paradoxical .
for example , small changes in
chemical structure often lead to correspondingly small changes in
free energy , but seemingly disproportionately large changes in enthalpy
and entropy .
similarly , the efforts of medicinal chemists to enhance binding
by making ligands more rigid , and thereby presumably reducing the
entropy penalty , sometimes enhances the binding enthalpy instead of
the entropy .
the ability to informatively decompose binding enthalpies , as done
here , should help resolve such calorimetric paradoxes .
moreover , by
combining an enthalpy calculation with a precise calculation of the
binding free energy , one can immediately obtain the binding entropy , a quantity which
has been notoriously difficult to obtain at high precision from simulations .
we anticipate that
continuing growth in computer power will likely make such computational
calorimetry studies routine before long , not only for host
we compute the enthalpy of binding as the difference between the
mean energies of four systems ( figure 6 ) , where
the two initial states are the free host and guest in aqueous solvent ,
and the final states are the complex in solvent as well as an amount
of pure solvent that exactly balances the solvent of the initial and
final states .
although this solvent - balance approach was reported
previously , it was presented without
derivation .
the theory subsection therefore derives this direct enthalpy
method ; the subsection entitled computational methods section then
details the simulations and their analysis .
the standard free energy change on binding may be written in terms
of the standard chemical potentials of the solvated reactant species , a , b and their product complex , ab:1 the standard chemical potential of
a solvated molecule or complex , x = a , b , or ab , at standard concentration
in idealute solution is2where r is the gas constant , c is the concentration
at standard state conditions ,
and znx , x and znx,0 are the partition
functions of nx water
molecules with and without the solute , respectively .
the symmetry
number x is included in case the
partition function of x is written in a manner that
includes indistinguishable conformations .
we have omitted the momentum contribution to the partition function ,
as this will cancel when one assembles an expression for the standard
free energy of binding from the chemical potential of the three molecular
species .
we also neglect a pressure volume term , as its contribution
to the binding enthalpy and free energy is negligibly small relative
to the other terms in a solvated system .
the chemical potential
x0 is the partial molar free energy
of species x = a , b , or ab and can be written in terms of the partial molar enthalpy hx and entropy sx0 : x0 = hx
the binding enthalpy then is
given by3 one may use the fact that4to write the partial molar
enthalpy as5 substituting eq 2 into eq 5 yields6 the two partition functions
here have the same basic form , z = edr , where u(r ) is the
potential energy of the system as a function
of r , which comprises the coordinates of the solvent
molecules as well as the solute , if present .
it is straightforward
to show that7where u is
the boltzmann average of the potential energy . substituting eq 7 into eq 6 yields the partial
molar enthalpy as8 here ,
the quantities in the
angle brackets are the mean potential
energies of the solute x with nx solvents , and of the nx solvent molecules without any solute , respectively .
finally , combining the partial molar enthalpies of the complex and
the free solutes yields the desired enthalpy change on binding as9 the
first three terms here are the difference in the mean energy
of the solute - water systems , and the last three terms are the mean
energies of the waters from each system without the solutes .
if dissolved
ions , such as sodium and chloride , are present in any of the simulations
with a solute present , then these must similarly be balanced between
the initial and final states ; see si . here
,
we evaluate the last term in eq 9 by computing
the mean energy of a box of waters with ( nab na nb )
water molecules , along with a balancing set of ions as may be required .
the initial docked poses
of the guests with cb7 were the lowest energy minima in a semiempirical
quantum energy landscape as found via an aggressive conformational
search .
the gaff force field was used for all the bonded and nonbonded parameters
of cb7 and the guest molecules .
partial atomic charges were generated
with the am1-bcc method as implemented in the
program antechamber .
each system ( free
cb7 , free guest , and cb7-guest ) was then solvated with tip3p and tip4p - ew explicit
water molecules .
the itc experiments
associated with the aliphatic guests were done in pure water , but ph buffers were used in the experiments
for the aromatic guests .
the experiments involving methylviologen
were done in the presence of 50 mm tris chloride at ph 7 , which corresponds to 1.3 tris and
cl ions in the volume of the simulation box , so
one of each ionic species was included .
the guests g8 and g9 were
studied in 10 mm sodium phosphate buffer , which corresponds to only 0.3 phosphates and 0.4 sodiums in our
simulation volumes , so these were not included .
the number of explicit
water molecules in each system was set such that the total number
of waters in the bound state ( complex and pure water simulations )
and in the free state ( cb7 and guest simulations ) were equal . for
each separate simulation ,
a langevin thermostat with the collision
frequency set to 1.0 ps was used for the nvt and
npt stages of equilibration , and the berendsen barostat with the pressure
set to 1 bar and the relaxation time set to 2 ps was used during the
npt stage of equilibration .
production npt simulations used the same settings for the thermostat
and barostat as during equilibration , except that the nonbonded cut
off value was set to 9.0 .
the first 10 ns of production simulation
were discarded to allow for additional equilibration .
the production
simulation times were at least 1 s for each system simulated
( pure solvent , cb7 , cb7guest , and guests ) for a total simulation
time of over 38 s across both water models .
we used
the sander module of amber 12 to recompute
the potential energy for each trajectory snapshot when
all the atoms are present ( total ) , when only the solvent is present
( solvent solvent ) , and when only the solute is present ( solute solute ) .
cpptraj was used for the generation of
all the modified topology and trajectory files necessary for the potential
energy decomposition analysis .
convergence of the total potential
energy was evaluated by plotting the cumulative average as a function
the total simulation time , and by using block - averaging analysis to estimate the standard deviation of the mean
potential energy .
all reported average potential energies have a standard
deviation of the mean of 0.13 kcal / mol or less ( see si ) ; thus , if the same simulation were repeated multiple times ,
with different randomly assigned initial velocities , the standard
deviation of the mean potential energy should be about 0.13 kcal / mol .
the mean energies obtained for our pure water simulations are within
0.3 kcal / mol of published values .
because the
binding enthalpy is an additive combination of four mean energies ,
the variances of the mean energies add , and the standard deviation
of the mean binding enthalpy is given by h = i = 14i2 , where i is the standard deviation of the mean for simulation i. several variations of this protocol were run for
one host
first , one test calculation used nvt production runs , with box volumes
set to the smallest or largest volume sampled from a prior npt simulation
of the same system .
these extreme tests yielded binding enthalpies
as much as 160 kcal / mol different from those obtained by otherwise
identical npt production runs . on the other hand , nvt calculations
with the box volume set to the average obtained from
the prior npt calculation yielded results very similar to those from
npt production runs .
we conclude that the mean energy is highly sensitive
to the volume and that it is safest to use npt conditions for enthalpy
calculations .
second , because the default gpu implementation
of amber employed here uses mixed precision arithmetic , we compared
the results to those from matched simulations using full double precision
on the gpu ; the two results differed by only 0.09 kcal / mol .
finally ,
to address possible concerns regarding the use of a cutoff for lennard - jones
interactions , we recomputed the energy
of each snapshot for cb7 and a2 , using the maximum cutoff value possible
given the size of the simulation box .
this change had minimal impact
( 0.07 kcal / mol ) on the computed binding enthalpy .
the significance of the
reported linear regression parameters and mean errors was assessed
through bootstrap resampling ( 100 000 samples ) of the computed
and experimental binding enthalpies , based on their respective means
and standard deviation of the mean . for the experimental data , the
reported standard deviations divided by the square root of the number
of independent runs were taken to be the reported uncertainties .
linear
regressions were performed for each bootstrap sample , and we report
the means , x , and standard deviations , , of the resulting regression
parameters , in the form x . the number of
atoms close to the host and guest , nclose , was calculated for all of the host , guest , and host
guest
simulations using 100 000 frames ( every 10 ps ) from each 1
s simulation via the radial command in cpptraj . for a given simulation , all host solvent ,
guest
solvent , and/or host guest pairwise interactions
within 4.25 were included in the average .
any self - pairwise
interactions ( e.g. , host host or guest guest ) were excluded
from the average pairwise count . | ### Summary:
: we used microsecond time scale molecular
dynamics simulations to
compute , at high precision , binding enthalpies for cucurbit[7]uril
( cb7 ) with eight guests in aqueous solution .
the results correlate
well with experimental data from previously published isothermal titration
calorimetry studies , and decomposition of the computed binding enthalpies
by interaction type provides plausible mechanistic insights .
thus ,
dispersion interactions appear to play a key role in stabilizing these
complexes , due at least in part to the fact that their packing density
is greater than that of water . on the other hand ,
strongly favorable
coulombic interactions between the host and guests are compensated
by unfavorable solvent contributions , leaving relatively modest electrostatic
contributions to the binding enthalpies .
the better steric fit of
the aliphatic guests into the circular host appears to explain why
their binding enthalpies tend to be more favorable than those of the
more planar aromatic guests .
the present calculations also bear on
the validity of the simulation force field .
somewhat unexpectedly ,
the tip3p water yields better agreement with experiment than the tip4p - ew
water model , although the latter is known to replicate the properties
of pure water more accurately .
more broadly , the present results demonstrate
the potential for computational calorimetry to provide atomistic explanations
for thermodynamic observations . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: levetiracetam ( lev ) is a new antiepileptic drug that is effective in adults and children with partial - onset seizures or idiopathic or symptomatic generalized seizures .
levetiracetam is a derivative of s - enantiomer pyrrolidone and is chemically similar to piracetam , preventing excitatory or inhibitory neurotransmitters from binding to the receptor .
the effects of lev on high - voltage neuron - specific ca influx through ca channels , gated gaba , and glycine are suggested to inhibit or reverse currents . na or t - type ca
levetiracetam - related side effects were observed at a rate of 17.251.3% and usually occurred within the first 5 months of treatment .
central nervous system side effects are the most common side effects but are usually mild ; other common side effects are irritability , drowsiness , and dizziness .
antiepileptic drug - induced skin reactions , most commonly with phenytoin ( pht ) , carbamazepine ( cbz ) , oxcarbazepine ( oxc ) , phenobarbital ( pb ) , lamotrigine ( ltg ) , and zonisamide ( zns ) and sometimes with pyrimidione , valproic acid ( vpa ) , topiramate ( tpm ) , gabapentin ( gbp ) , tiagabine ( tgb ) , and lev are rarely reported .
mycosis fungoides ( mf ) is a cutaneous t - cell lymphoma characterized by the malignant proliferation of t cells with phenotypic and functional properties of t - helper cells .
mycosis fungoides is a low - grade lymphoproliferative disorder caused by cd4 + lymphocytes .
mycosis fungoides - like skin reactions resulting from pht , cbz , and oxc have been previously reported in the literature .
we report the case of a patient who was taking the anticonvulsant drug levetiracetam and in whom skin lesions developed that showed histological features suggestive of mycosis fungoides .
a thirty - one - year - old male patient presented at uludag university medical faculty department of neurology epilepsy clinic with generalized seizures . once asleep , the patient , who had no history of systemic diseases , was given jtkn twice in a 10-month period .
after neurological examination , routine blood tests , and mri ( fig . 1 ) of the patient ,
all of which were normal , lev ( 500 mg / day ) was started . during the wakefulness and sleep portions of the patient 's eeg , left frontal theta- and sharp - wave activities were observed ( fig . 2 ) .
approximately 2 months after lev initiation , a pale , pinkish , macular erythema with unclear borders was observed at the sides of the abdomen ( fig .
laboratory test results revealed no peripheral blood eosinophilia , normal renal and liver enzymes , and negative vasculitic parameters ( ana , anti - ndna ) .
a skin punch biopsy revealed mild infiltration of perivascular mononuclear inflammatory cells in the dermis .
mycosis fungoides , as a reaction to drug administration , was thought to be the cause . the patient recovered by reducing his dosage of lev and of other medications capable of causing rare skin reactions ;
we concluded that a mycosis fungoides - like drug reaction was the cause . the patient recovered by reducing his dosage of lev and of other medications capable of causing rare skin reactions ;
although antiepileptic drug - induced skin reactions , including maculopapular rash , are very rare , cases such as stevens johnson syndrome and toxic epidermal necrosis have been reported .
mycosis fungoides is a peripheral non - hodgkin 's t - cell neoplastic process , representing the most common type of primary cutaneous malignant lymphoma .
anticonvulsant - induced pseudolymphomas usually develop within 2 to 8 weeks of drug use .
although skin lesions usually resolve within 3 to 4 weeks after discontinuing the offending agents , long - term follow - up is needed to assure the absence of lymphoproliferative malignancy .
our patient developed a pale , pinkish , erythematous , macular lesion on both sides of the abdomen approximately 3 months after lev initiation .
there are two main groups of drug - induced pseudolymphomas : those that clinically and histological simulate cutaneous lymphomas and those known as hypersensitivity syndromes .
pseudolymphomas can not be differentiated from true lymphomas through clinical , pathological , or molecular findings .
a definitive test for diagnosis is the resolution of the lesions after the medication involved is suspended .
mycosis fungoides - like skin reactions to pht , pb , cbz , and oxc have been previously reported in the literature .
reported patients showing histological features suggestive of mf who were taking the anticonvulsant drug diphenylhydantoin .
after using lev , our patient , upon histopathological examination , exhibited mild perivascular mononuclear inflammatory cells in the papillary dermis suggestive of an anticonvulsant - induced pseudolymphoma .
however , a detailed history along with dermatological examinations failed to reveal a connective tissue disease .
the choice of treatment for patients with mf varies depending on the stage involved and the site of the lesions .
treatment should be considered in all patients , irrespective of staging , as it has been shown to improve the prognosis even in the early stage of disease .
puva , topical nitrogen mustard , and topical corticosteroids are the main options for early - stage disease .
the patient was diagnosed with a drug - induced pseudolymphoma , and topical corticosteroid therapy was initiated .
antiepileptic drugs , especially pht and cbz , can produce pseudolymphoma , and pht , cbz , and oxc can induce mf - like skin reactions .
mycosis fungoides - associated pseudolymphoma was first mentioned in the literature in 1982 as a result of the use of diphenylhydantoin and has been referred to by different names , such as , in 1985 , phenytoin - related mf - like lesions and , in 1997 , also caused by phenytoin , pseudomycosis fungoides syndrome . in recent years ( 1990 and 2001 ) , in cases of cbz use , mf - associated pseudolymphoma has been referred to as mimicking mycosis fungoides ; in 2003 , it was termed pseudomycosis fungoides , , , , . in 2011 ,
navarro and his colleagues reported a 45-year - old female patient who used oxc for 2 months and developed a mycosis fungoides - like syndrome , as evidenced by a skin biopsy .
in our case , cutaneous lesions were evaluated by a dermatologist after approximately 3 months of taking lev . after making the differential diagnosis of mf disease
it has been observed in the literature that drugs such as cbz , oxc , pht , and pb have an mf - like impact mechanism .
however , our case involved lev , which is a different drug than those referenced in the literature .
there have been no prior reported cases of mf - like disease associated with lev .
we think that this could be the first appearance in the literature of mf - like disease associated with lev and a different mechanism of action that causes an mf - like skin reaction . | ### Summary:
: levetiracetam is a relatively new antiepileptic drug that has previously not been associated with severe dermatological side effects .
we report the case of a 31-year - old male treated with levetiracetam for seizures who subsequently developed a mycosis fungoides - like drug reaction that resolved upon dosage reduction . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: when developing countermeasures against mers - cov infection , rodents and small animal models that mimic human disease hallmarks would be useful in initial screening studies before the measure is tested in larger animals ( e.g. , nonhuman primates and , potentially , camels ) .
although upper respiratory tract disease develops more severely in the latter ( 11 ) , studying immune correlates of protection and vaccine efficacy in camels ( the only natural host besides bats and humans identified thus far ) may reveal vulnerabilities of mers - cov that may be exploited for human vaccine strategies .
existing small animal species do not naturally express the primary receptor that mers - cov uses to infect humans , the human dipeptidyl - peptidase 4 ( hdpp4 ) receptor ( 1219 ) .
this lack results in the animal s inability to sustain infection and for clinical illness to develop from mers - cov .
larger animal models , such as nonhuman primates , have not yet been optimized to consistently mimic the disease patterns observed in human infection ( which is incompletely understood ) and also have associated logistical challenges because that work must be completed in biosafety level 3 facilities .
although efforts have been made to adapt mers - cov itself to exhibit human disease phenotypes in rodents , greater success has been achieved through the development of specialized mouse models that express hdpp4 ( 2022 ) .
mouse strains that globally express hdpp4 are susceptible to infection by mers - cov , and the mice display lower respiratory tract infection , weight loss , and increased respiratory rate , but also encephalitis , which makes the strains highly lethal .
human dpp4 expression is , however , transient and limited to the lung after ad5-hdpp4 transduction by intranasal inoculation ( 21 ) .
these infected transgenic mice exhibit transcriptional activation of genes encoding classic antiviral cytokines ( interferon [ ifn]- , ifn- , and mx-1 ) and pro - inflammatory cytokines ( interleukin [ il]-2 , il-6 , il-12 , p40 , il-1- , and tumor necrosis factor [ tnf]- ) , as well as chemokines ( granulocyte - colony stimulating factor [ g - csf ] , monocyte chemoattractant protein-1 [ mcp-1 ] , interferon gamma - induced protein 10 [ ip-10 ] , cxc motif ligand 1 [ cxcl-1 ] , macrophage protein 1 [ mip-1 ] , and chemokine ( c - c motif ) ligand 5 [ ccl5 or rantes ] ) , in contrast with the negligible gene activation of infected nontransgenic mice .
il-1 , il-6 , tnf- , g - csf , mcp-1 , ip-10 , cxcl-1 , mip-1 , rantes , and interferon - induced gtp - binding protein ( mx-1 ) have been detected in the lungs and brains of infected transgenic mice ( 20 ) .
human dpp4 dimers in transgenic mice could affect immune regulation and lead to poorly understood outcomes that could confuse the interpretation of disease natural history and vaccine efficacy .
alternatively , a minimally modified version of mouse dpp4 , by mutation of 2 amino acids , can support mers - cov infection .
mice with this mutation experience severe lower respiratory tract infection , although they do not exhibit brain infection ( 16 ) .
in addition , pascal et al . have developed mice that express hdpp4 , under the control of its endogenous promoter and the 3 untranslated region , and show lung - specific infection and inflammation ( 22 ) .
further testing may prove that vaccine evaluation in these small animal models could lead to a better understanding of immunogenicity and efficacy of vaccine candidates and the therapeutic measures being considered for evaluation in larger animals and humans . among current nonhuman primate models , rhesus macaques display mild - to - moderate clinical signs on viral challenge ( 23 ) , whereas the common marmoset is reported to exhibit more severe signs of infection ( 24,25 ) and could be a better model for the severe clinical syndrome observed in mers - cov infected persons .
however , not all research groups have been able to replicate severe disease outcomes in marmosets .
factors contributing to this could include variations in physical location , age , and origin of the marmosets ; challenge virus strains and stocks ; route and dose of inoculation ; and in protocols . to be able to provide robust and reproducible outcomes ,
camels are also being used to evaluate mers - cov infection , and findings from adney et al . showed that these animals are unique in that they experience an upper respiratory tract infection .
although we do not know the efficiency of airborne versus droplet or another mode of transmission , viral shedding from the upper respiratory tract might explain the efficiency of camel camel and camel human transmission ( 11,26 ) .
although camels do not display the severe disease symptoms observed in infected humans ( 26 ) , a camel infection model remains useful for understanding the disease in camels and identifying potential immune correlates of protection induced by vaccination .
veterinary countermeasures could form part of a one health strategy to forestall zoonotic transmission to humans ( 1 ) .
hesitation to implement animal vaccination strategies in camels once a vaccine becomes available can be attributed to the absence of severe disease in camels ( only upper respiratory tract infection with rhinitis ) and to skepticism among key groups regarding zoonotic transmission of mers - cov to humans ( e.g. , camel breeders ) .
although the animal models for evaluating mers - cov infection represent progress , they do not recapitulate the pathogenesis of severe human disease .
a combination of both small and large animal models should be considered for evaluation of preventive and therapeutic candidates for mers .
regardless of the chosen model , comparing and interpreting results effectively and reducing discrepancies among laboratories will be crucial for researchers to agree on a set of standards with respect to experimental design , including variables for age of animals , specimen handling , route of administration , type of virus challenge , inoculation schedule , sample collection , and disease scoring algorithms .
building on the experience from the closely related severe acute respiratory syndrome coronavirus ( sars - cov ) ( 27 ) , researchers have been actively working to understand mers - cov genetics to inform vaccine and therapeutic development efforts .
they quickly demonstrated that the spike ( s ) protein , a viral surface glycoprotein , was essential for recognition of hdpp4 and viral entry into cells and likely represented a prime target for immunogen design for the development of vaccines and monoclonal antibodies ( 18,28,29 ) . at the workshop
, we reviewed various approaches all in preclinical development and all based on the s protein or one of its components , including nanoparticles , subunit proteins and peptides , dna , various viral vectors , and live attenuated mers - cov .
nanoparticles formed with mers - cov s protein , under development by novavax ( gaithersburg , maryland , usa ) , have been shown to induce virus neutralizing antibodies ( nabs ) in mice after a single injection ; proprietary adjuvants enhance this response ( 30 ) .
vaccines using antigens expressed from the baculovirus platform developed by novavax have been evaluated in human subjects in the context of phase i and phase ii clinical studies for other infectious diseases without notable vaccine - related safety concerns ( 3133 ) .
portions of the s protein , specifically the receptor - binding domain ( 8,29,3436 ) , are also being developed as subunit vaccines .
critical neutralizing region and induce strong immune responses and nabs in mouse models ( 37,38 ) .
moreover , the subunit vaccines have been shown to protect transgenic mice when challenged with mers - cov , indicating that vaccines focused on the receptor - binding domain may be sufficient for protective immunity to develop against the virus ( 39,40 ) .
several viral vectors , including adenovirus ( 41,42 ) , modified vaccinia ankara ( mva ) ( 43,44 ) , and measles virus ( 45 ) , are also under development by different groups .
various lengths of s protein are being expressed on these platforms and are able to generate antibodies in animals that can neutralize mers - cov in vitro and , at least for some vector platforms , also generate cellular immune responses ( 43,45 ) . for mva- and measles virus based vaccines ,
mva constructs , which have established safety profiles in humans , have been tested in camels and can induce protective immunity , representing a potential veterinary technology ( 46 ) .
moreover , on the basis of supportive data from animal studies , these mva constructs will soon enter clinical trials .
vaccines based on live attenuated viruses historically have been shown to be highly efficacious ; they are also safe and generally well tolerated .
enjuanes and others reported to the group the development of 2 engineered mers - cov vaccine candidates .
one candidate was based on a propagation - defective mers - cov strain , and another was a live attenuated virus with 3 safety guards that used a mers - cov infectious cdna clone ( 47 ) .
an inactivated sars - cov vaccine was shown to be safe and able to induce nabs in a phase i trial ( 48 ) .
dna vaccines are generally perceived as a safe , stable platform for in vivo antigen expression .
a sars - cov dna vaccine , which expresses the sars - cov s protein , has been shown to induce nabs and functional t - cell responses in humans ( 49 ) .
geneone ( blue bell , pa , usa ) is developing a proprietary , full - length s protein dna vaccine candidate that has been shown to induce nabs and highly functional t cells in various animal models and protect rhesus macaques from infection after mers - cov challenge when the vaccine is administered with electroporation to enhance uptake of the plasmid dna ( 50 ) .
concerns remain regarding the immunogenicity of dna vaccines in humans , although the effects of using therapeutic vaccination strategies for other diseases raise the potential for dna - only approaches ( 51 ) .
in addition , modjarrad reported that using a prime - boost format , a full - length s protein dna vaccine , followed by an s - protein boost , can increase nab titers , reduce the clinical severity of mers , and increase the durability of protection in macaques ( 52 ) . to complement active immunization approaches
, researchers are also advancing several prophylactic or therapeutic approaches against mers - cov using nab technologies through preclinical development . because these nabs target epitopes of the s protein ( or specifically the receptor - binding domain )
, they can cause precise and potent inhibitory effects on viral entry in small and large animal models ( 53 ) .
the mechanisms of neutralization have been uncovered and are typically mediated by blocking mers - cov binding to hdpp4 ( 22,52,5456 ) . as the supplementary agents of antibodies , the peptidic mers - cov fusion inhibitors targeting the conserved region in the s protein hr1 domain region are highly potent in inhibiting infection of mers - cov strains , including those resistant to nabs .
intranasal administration of the peptides protected hdpp4-transgenic mice from mers - cov challenge , suggesting that , alone or in combination with nabs , these peptides could be used to prevent and treat mers - cov infection ( 37,39,57 ) . further characterization of these technologies and the potential for combination approaches are ongoing as investigators tackle questions related to viral escape ( 58,59 ) .
preliminary results indicate that viruses that evade antibody neutralization have reduced viral fitness , demonstrating that escape can occur but comes at a cost to fitness .
marasco noted that sequencing of circulating strains will be critical to monitor viral evolution ( 60 ) , which will only be possible with increased sample- and data - sharing .
ongoing studies related to cross - reactivity with human tissue and the effects of polyclonal and nonneutralizing antibodies are also underway as passive immunotherapy becomes more accepted to prevent and treat mers - cov infection .
overall , selecting specific technologies and approaches that warrant further development is difficult , given the diversity of models and readouts and the concomitant need for greater standardization in the field .
although each technology presents unique advantages and deficiencies related to desired immunogenicity , safety , durability of protection , need for adjuvant , and manufacturing considerations , some technologies have a long track record in the clinic , which would potentially simplify their development and regulatory pathway . given the public health urgency , these platforms ( or combinations thereof ) should be made a priority .
the experience with sars - cov offers a sobering lesson : countermeasures that advance on the basis of promising preclinical data may ultimately exacerbate disease in humans .
antibody - dependent enhancement of infectivity has been observed in cell culture in which a human promonocyte cell line is used 6163 ) . in mice and hamsters vaccinated with a recombinant native full - length sars - cov s protein trimer , serum igg developed that blocked binding of the s protein to the ace2 receptor and neutralized sars - cov infection in vitro .
sars - cov entered human b - cell lines in an fcrii - dependent and ace2-independent fashion , indicating that antibody - dependent enhancement of virus entry is a novel cell entry mechanism of sars - cov .
vaccinated animals showed no signs of enhanced lung pathology or hepatitis , and viral load was undetectable or greatly reduced in lungs after challenge with sars - cov ( 64 ) .
however , in the presence or absence of adjuvant , vaccination of mice with viruslike particles or inactivated virus induced eosinophilic immunopathologic changes in young and aged mice ( 6567 ) .
the pulmonary immunopathologic features , on challenge with sars - cov , were associated with th2-type immunopathology with prominent eosinophil infiltration .
although no enhancement of immunopathologic features has been observed in mers - cov vaccinated and challenged animals , future studies of mers - cov vaccines in animals and humans should consider that possibility .
to date , commitment to open communication regarding mers - cov vaccine development has been haphazard , and leaders in the field are calling for a new approach that integrates resources to accelerate science and enhance biosecurity . new norms and standards are under development by the world health organization ( who ) to streamline sample collection ( type , storage and availability , quality control ) ; and information dissemination and publication . combining resources available in saudi arabia , south korea , the united states , europe , and beyond to develop countermeasures for mers - cov , an
open innovation paradigm shift can maximize public sector investment , provide robust information for a systems - level approach , and deliver the necessary public health effect that is urgently needed .
the saudi arabia moh , working with saudi academic institutions , who , and other stakeholders , recognizes the crucial role it has to play in defining the public health goals that will guide vaccine development efforts for mers - cov ( 68,69 ) .
researchers , vaccine developers and health authorities must understand how a vaccine is expected to fit into the larger public health strategy to combat mers ( e.g. , target populations and vaccination strategies , level of efficacy , safety profile for a vaccine ) , as well as the pathway to future vaccine testing ( e.g. , design of efficacy trial ) , licensure and access .
few vaccine developers in the mers arena have experience conducting preclinical and clinical research in the middle east , and the saudi moh and saudi food and drug authority have a valuable role to play in defining the expectations for future clinical studies and in educating developers on the associated regulatory pathway .
the potential threat posed by mers - cov necessitates a multipronged approach to the development of effective countermeasures .
accelerating the development of a vaccine requires a better understanding of mers - cov epidemiology , transmission , and pathogenesis in humans and animals .
this information will help develop target product profiles for human and veterinary vaccines , which in turn will facilitate planning for efficacy trials and inform development strategies .
2 . because current animal models do not fully reflect hallmarks of severe human disease , a combination of both rodents and nonhuman primate models should be considered in evaluating and developing preventive and therapeutic candidates under standardized conditions .
current vaccine development strategies involve a variety of technology platforms , primarily targeting the mers - cov s protein . given the public health urgency , platforms ( or combinations thereof ) with an established safety track record in humans should be given priority .
other target species such as dromedary camels should also be considered for the development of veterinary vaccines as a one health approach .
attention should be paid to lessons learned from sars - cov vaccine development efforts , particularly to signs of potential disease enhancement in various animal models .
therapeutic antibodies are recognized as potentially useful tools in mers prevention and treatment , but the concern around escape mutants with increased fitness , although concern is not limited to this technology type , warrants continued investigation and surveillance .
such an approach could be considered alone or in combination with vaccine approaches . as supplementary agents ,
an opportunity exists for greater coordination around specific technology platforms and to ensure that appropriate incentives are considered to stimulate research and development collaboration from academia , industry , nongovernmental organizations , and governments .
the saudi arabia moh , working with who and other stakeholders , has a crucial role to play in defining the public health goals that will guide vaccine development efforts .
funding agencies , nongovernmental organizations , and companies recognize the need for cooperation and have resolved to formalize a collaborative model .
the field recognizes the opportunity to set a precedent for how it collaborates as a global community in the context of an emerging disease , building on lessons learned from the recent international response to the ebola epidemic .
although still subject to consultation , key components of a partnership(s ) were identified , including coordinating funding , sharing samples / data , advancing preclinical models , beginning clinical trials in regions having outbreaks , and standardizing assays and reagents for testing .
exact partnership structures remain to be determined but should at the very least allow for coordination of activities through frequent , transparent , and open discussions among funding agencies and stakeholders .
future models , including a formalized consortium of players who would make a long - term commitment to advance selected products through development phases , can be contemplated once technologies are evaluated more rigorously .
regardless of the final partnership structure(s ) , the core of any collaborative strategy should include sharing of data and samples and standardizing laboratory assays to ensure that everyone learns from each other , are able to compare technologies , and ultimately accelerate the development of new solutions . | ### Summary:
: middle east respiratory syndrome ( mers ) remains a serious international public health threat . with the goal of accelerating the development of countermeasures against mers coronavirus ( mers - cov ) , funding agencies , nongovernmental organizations , and researchers across the world assembled in riyadh , saudi arabia , on november 1415 , 2015 , to discuss vaccine development challenges .
the meeting was spearheaded by the saudi ministry of health and co - organized by the international vaccine institute , south korea .
accelerating the development of a preventive vaccine requires a better understanding of mers epidemiology , transmission , and pathogenesis in humans and animals .
a combination of rodent and nonhuman primate models should be considered in evaluating and developing preventive and therapeutic vaccine candidates .
dromedary camels should be considered for the development of veterinary vaccines .
several vaccine technology platforms targeting the mers - cov spike protein were discussed .
mechanisms to maximize investment , provide robust data , and affect public health are urgently needed . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: the advisory committee on immunization practices ( acip ) and the healthcare infection control practices advisory committee recommend that all hcws be vaccinated annually against influenza .
vaccination of hcws against influenza has been shown to prevent transmission of influenza to patients [ 2 , 3 ] , coworkers , and families . despite these benefits ,
vaccination uptake is limited by concerns regarding vaccine safety and efficacy and misconceptions regarding the perceived risk of nosocomial transmission of influenza .
late in the 2010 - 2011 influenza season , we instituted a novel incentive to promote influenza vaccination , providing one - hour paid time off immediately following receipt of vaccination , and we achieved our target vaccination rate soon after this incentive program was begun .
based on this experience at our medical facility , we sought to evaluate formally the effect of this time off incentive on attitudes towards influenza vaccination during the 2011 - 2012 influenza season .
we hypothesized that hcws who had received the influenza vaccine would report a more favorable attitude regarding this incentive ( as compared with unvaccinated hcws ) .
in addition , we sought to identify other attitudes associated with acceptance of influenza vaccination at our medical center .
the philadelphia veterans affairs ( va ) medical center is a federal health care facility that includes outpatient clinics , a 145-bed acute care hospital , and an adjoining 240-bed long - term care facility . in our facility ,
influenza vaccine is provided free of charge by a nurse - staffed roving cart that visits each floor of the facility on several occasions during the influenza season .
the target vaccination rate for the facility , established by the national va administration , was 80% for the 2010 - 2011 influenza season and 85% for the 2011 - 2012 influenza season .
all hcws were invited by email and newsletters to complete an anonymous web - based survey ( surveymonkey ) , developed with input from infection control practitioners at the authors ' institutions and piloted in a convenience sample of employees at the philadelphia va medical center across a range of job duties .
we excluded survey respondents who indicated that they were not hcws at our facility during the period of the incentive .
we described respondents ' characteristics and attitudes toward influenza vaccination , including their agreement or disagreement with the statement , the one hour of time off award made a difference in my decision whether to accept the flu vaccination .
we then classified survey respondents into two groups : those that accepted or did not accept influenza vaccination during the 2011 - 2012 influenza season .
we determined the relationship of specific attitudes with respondents ' acceptance of influenza vaccination , using a 5-point likert scale ( 1 strongly disagree to 5 strongly agree ) .
we used the nonparametric kruskal - wallis test to compare likert responses between the two groups .
we obtained 195 survey responses out of 2473 paid employees at the philadelphia va medical center , corresponding to a response rate of 8% . after excluding 41 respondents who indicated that they were not hcws at our facility during the 2011 - 2012 influenza season , we analyzed survey responses from 154 hcws employed at the philadelphia va medical center .
132 respondents ( 86% ) reported receiving the influenza vaccine during the 2011 - 2012 influenza season .
the overall vaccination rate for hcws at the medical facility for the 2011 - 2012 influenza season was 61% .
we compared the likert scores for respondents with and without influenza vaccination during the 2011 - 2012 influenza season ( table 2 ) .
hcws that did not receive influenza vaccination during this time period indicated significantly greater concerns regarding the safety and efficacy of the influenza vaccine .
furthermore , these hcws minimized their personal risk of influenza given their duties as hcws , compared to respondents that reported a history of vaccination .
a total of 137 respondents indicated their attitude towards the time off intervention , with a mean likert score of 2.7 . among 121 respondents who reported receiving influenza vaccination , 63 ( 52%
, 95% ci 4361% ) reported disagreement with the statement that the time - off incentive made a difference in their decision to accept influenza vaccination , 24 ( 20% , 95% ci 1328% ) reported a neutral attitude towards this statement , and 34 ( 28% , 95% ci 2037% ) reported agreement with this statement .
in our study , the attitudes of hcws towards the paid time - off incentive were not associated with their decision to accept influenza vaccination .
interventions to improve vaccination rates among hcws such as educational programs [ 911 ] and facilitated access have resulted in modest improvements in influenza vaccination rates .
thus far , incentives alone ( without other program components ) have not been found to improve vaccination rates among hcws .
similar to prior studies , we found that influenza vaccination acceptance was limited by negative attitudes concerning vaccine efficacy and safety [ 7 , 9 ] .
we also observed that unvaccinated hcws reported less concern regarding their personal risk of contracting influenza in the healthcare setting .
recent work to understand the factors that motivate influenza vaccination , based on the theory of planned behaviors , suggests that these motivational attitudes are the primary determinants of the intention to be vaccinated against influenza , rather than logistical concerns such as the convenience or cost of vaccination .
our study has several important limitations . given the more than 2,000 hcws that are employed at the philadelphia va medical center , our response rate was small , and the anonymous nature of the survey did not permit us to compare respondents and nonrespondents , leading to the potential for sampling bias .
this potential bias is particularly important given the small number of respondents who reported not receiving the seasonal influenza vaccine during the 2011 - 2012 season . because of the anonymous nature of the survey , influenza vaccination status was based on self - report .
finally , we did not assess vaccination status during the preceding ( 2010 - 2011 ) influenza season , which has been shown to be the strongest predictor of acceptance of vaccination during subsequent seasons . despite these limitations
, our study provides evidence that modest incentives such as one - hour paid time off will be unlikely to promote influenza vaccination rates within medical facilities .
more potent interventions that include mandatory vaccination combined with penalties for noncompliance will likely provide the only means to achieve near - universal influenza vaccination among hcws . | ### Summary:
: objectives .
the national influenza vaccination rate among healthcare workers ( hcws ) remains low despite clear benefits to patients , coworkers , and families .
we sought to evaluate formally the effect of a one - hour time off incentive on attitudes towards influenza vaccination during the 2011 - 2012 influenza season .
methods .
all hcws at the philadelphia veterans affairs ( va ) medical center were invited to complete an anonymous web - based survey .
we described respondents ' characteristics and attitudes toward influenza vaccination and determined the relationship of specific attitudes with respondents ' acceptance of influenza vaccination , using a 5-point likert scale .
results .
we analyzed survey responses from 154 hcws employed at the philadelphia va medical center , with a response rate of 8% . among 121 respondents who reported receiving influenza vaccination , 34 ( 28%
, 95% ci 2037% ) reported agreement with the statement that the time off incentive made a difference in their decision to accept influenza vaccination .
conclusions .
our study provides evidence that modest incentives such as one - hour paid time off will be unlikely to promote influenza vaccination rates within medical facilities .
more potent interventions that include mandatory vaccination combined with penalties for noncompliance will likely provide the only means to achieve near - universal influenza vaccination among hcws . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: an adequately sampled tumor histology that is evaluated by an experienced neuropathologist is the current international standard for the diagnosis of high - grade gliomas and sets the stage for adjuvant treatment in the field of neurooncology .
however , standard histology , including h&e staining , and standard immunohistochemistry markers , such as gfap , neglect the recent development of molecular markers as well as clinical and imaging information .
a 30-year - old female presented at our clinic with moderate aphasia of a few weeks duration 14 days after she had been diagnosed with anaplastic astrocytoma based on an open biopsy of her left temporal lobe at an external hospital .
she had a 2-year history of complex focal epileptic seizures prior to diagnosis . due to a substantial mass effect of the remaining tumor ,
an interdisciplinary consensus was followed , and part of the remaining tumor was resected with a substantial relief of the mass effect ( fig .
1a ) and almost complete recovery of aphasia , with a karnofsky performance score of 90% .
the diagnosis of anaplastic astrocytoma was confirmed by the local neuropathologist , taking into consideration that some of the reactive and regressive changes ( fig .
the presence of a mutation of isocitrate dehydrogenase ( idh1 ) , a marker of grade ii and iii gliomas and secondary glioblastomas , substantiated the diagnosis .
after central review of the histology by 2 reference neuropathologists , randomization into an international clinical trial for anaplastic gliomas was rejected due to the fact that necrosis in the histological samples obtained during the second surgery qualified , in the view of the reference neuropathologists , as glioblastoma . at that point ,
considering the size of the residual tumor mass and in view of the clinical history and an mri suggestive of a rather aggressive high - grade glioma , we decided to start the patient on radiochemotherapy with temozolomide according to the stupp protocol .
we believe that this case illustrates some of the limitations of the current process of how diagnoses for patients with high - grade gliomas are made .
first , a tumor biopsy , open or stereotactic , selects a small portion of the tumor which may not necessarily represent the total tumor mass .
second , molecular information , such as idh1 mutation , can add substantial information to the kind and dignity of the tumor .
third , information from mri and the dynamics of the clinical course may substantially differ from the histological information from the tumor biopsies and may enhance a comprehensive evaluation of the individual course . and
fourth , local and particularly central review neuropathologists are often not adequately supported with clinical and imaging information to make a conclusive diagnosis . since a change in the diagnosis implicates a substantial change in the treatment for the affected patient , we therefore mandate gross total resections , whenever applicable , to obtain a maximal amount of tumor material , along with the integration of imaging and clinical information in the material submitted to local and central neuropathology .
we think that the minimal time delay incurred before treatment by establishing such an algorithm would be negligible ; the algorithm would favor diagnostic accuracy and advance both standard treatment and the homogeneity of study populations within centrally reviewed clinical trials . | ### Summary:
: an adequately sampled tumor histology that is evaluated by an experienced neuropathologist is the current international standard for the diagnosis of high - grade gliomas .
we present the case of a 30-year - old female for whom clinical and radiological information dramatically changed the histological diagnosis .
we suggest a new algorithm including these parameters to refine the accuracy of histological diagnosis both for standard treatment and centrally reviewed clinical trials . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: distension of the hollow organs has been induced by ambient air since the introduction of endoscopes for gastrointestinal ( gi ) indications .
the ambient air is delivered at the distal end of the endoscope with a fixed amount per minute by the operator 's pushing of the air button .
standard gastroscopes and colonoscopes are of little difference with respect to the amount of delivered air . in the last years , carbon dioxide ( co2 ) instead of ambient air has become the standard in colonoscopy and endoscopic examinations with longer operation times , such as double balloon enteroscopy or mucosectomies . while insufflated air mainly leaves the patient 's body per vias naturales ,
i.e. either the esophagus , small bowel or finally the colorectum , diffusion is not fast enough to clear these volumes to guarantee harmless endoscopic procedures .
ambient air consists mainly of nitrogen , which has a very slow diffusion capacity in human tissue , while the amount of co2 is only about 0.03% .
therefore the operator always has to keep in mind which amount of gas ( air or co2 ) will be delivered into the hollow organs .
important variables are examination time , ambient air versus co2 insufflation , diameter of the endoscope channel , operator 's fingers on the push button and setting of the air pump . anyhow emergency gastroscopies seem to harbor an elevated risk for development of air - induced complications .
using water instead of air may be of help , but is dangerous as well in upper endoscopy without airway protection .
repetitive suction of air during the examination should be done as often as visibility allows .
barotrauma in the gi tract occurs in scuba diving , gi endoscopy , noninvasive ventilation or in blast injuries ; pertaining gi endoscopy in the colorectum is affected mostly . in this context
upper gi perforation is very rarely caused by barotrauma and only rare information exists in the literature , apart from reports on barotrauma due to bag ventilation or resuscitation .
whether an acute upper gi bleeding influences gas transport along the small and large bowel , predisposing for a compartment syndrome , is not known to date . at our tertiary referral center ,
five situations with an iatrogenic compartment syndrome after upper gi endoscopy were documented in the last 2 years , always leading to a life - threatening situation .
alertness concerning the insufflation process in gi endoscopy will help prevent distension - associated diseases . from now on this entity has to be taught in endoscopy education .
esophageal variceal bleeding was suggested in a 37-year - old unconscious woman with overt bleeding from the mouth and anus , who was admitted to our emergency room with an initial hemoglobin of 2.7 g / dl and an initial systolic blood pressure of 80 mm hg .
esophageal variceal bleeding was suggested due to the information that the patient had been drinking daily since early youth and that 2 weeks before admission to the emergency room , the patient had had to go to the family doctor because of becoming jaundiced . the model for end - stage liver disease ( meld )
emergency endoscopy was performed directly using a large channel ( 6 mm diameter ) endoscope .
after 1 h of endoscopy , mechanical ventilation became impossible due to an abdominal compartment syndrome .
immediate laparotomy was performed and the stomach had to be evacuated from air and coagula manually with a simultaneously positioned 52-f tube . to stop the ongoing bleeding after coagula evacuation ,
a sengstaken - blakemore balloon was placed . during the first 24 h the patient received 16 erythrocyte concentrates , 2 platelet concentrates , 1,200
ml fresh frozen plasma , 10 g fibrinogen and coagulation factors ( 2,000 iu beriplex , see table 1 , plus 1,250 iu coagulation factor xiii ) .
due to repetitive declines in hemoglobin and the endoscopic proof of bleeding from the esophagus , the patient got a transjugular intrahepatic portosystemic shunt ( tipss ) inadequately lowering the directly measured portal pressure from 46 to 35 mm hg 2 days later .
the patient 's hepatic function , however , remained impaired , the reason why the patient was listed for transplantation on hospital day 5 ( meld score at that time was 29 ) and transplanted on hospital day 12 . today , 2.5 years later , the patient is in good health . a 56-year - old woman with non - steroidal anti - inflammatory drug ( nsaid ) ( acemetacin 6090 mg ) intake due to chronic polyarthritis
the initial hemoglobin value measured in the emergency room was 3.5 g / dl , the initial median arterial pressure was 50 mm hg .
after tracheal intubation , a gastroscopy was started using a 2.8 mm working channel endoscope parallel to an intravenous therapy with a proton pump inhibitor ( 80 mg as bolus followed by 8 mg / h for the next 72 h ) . as a large coagulum filling most of the stomach
was detected , the endoscope was exchanged for the large channel endoscope ( 6 mm diameter ) . shortly thereafter , ventilatory problems occurred and a ct scan was immediately arranged presenting extensive meteorism without evidence of perforation .
a second endoscopy was done after exclusion of perforation showing an ulcer with a visible vessel ( forrest iia , fig .
the patient did not suffer from additional symptoms during the following days and was discharged 6 days later . initially the 83-year - old patient had been transferred to a peripheral hospital , but due to hemodynamic instability he was transferred to our center .
he had been diagnosed with carcinoma of the stomach 1 week before and presented with acute onset of hematemesis and a decline of the hemoglobin value from 9.5 to 6.7 g / dl within a week .
after arrival at our center the hemoglobin had risen to 8.9 g / dl due to the application of two erythrocyte concentrates .
after tracheal intubation a gastroscopy was started . due to large amounts of blood it was switched to the large channel endoscope ( 6 mm diameter ) .
after 5 min the patient developed massive abdominal distension with increasing difficulties of mechanical ventilation . a perforation was presumed .
ct scan showed massive distension of the stomach and small bowel without perforation ( fig .
repeated endoscopy showed an ongoing bleeding near the cardia which could not be stopped ; besides the patient developed an abdominal compartment syndrome with a bladder pressure of 37 mm hg . therefore an emergency laparotomy was performed . at that point
the tumor affected not only the stomach but had also infiltrated the pancreas and colon as well as eroded the splenic artery . due to the only marginal survival chance in case of an extensive surgery and a controlled bleeding at that time , the operation was finished after exploration .
postoperatively the patient remained circulatorily and hemostatically instable , leading to death within hours . a 78-year - old patient , who was hospitalized due to tachycardic atrial fibrillation and aortocoronary bypass surgery , developed upper gi bleeding on hospital day 9 .
3a ) . despite ulcer treatment with endoclips as well as proton pump inhibitor therapy ,
the patient again developed a bleeding leading to another upper endoscopy 6 days after the first endoscopy . despite revealing an in situ present clip on one of the duodenal ulcers , the endoscopy showed large amounts of blood and coagula in the duodenum ( fig .
the site of bleeding , however , could not be located . within a few minutes , increasing difficulties in the patient 's mechanical ventilation occurred , and increasing norepinephrine requirement from 10 to 50 g / kg / min made an emergency treatment by rumenocentesis necessary .
the immediately performed emergency surgery revealed a massive distension with several serosal disruptions of stomach , small intestine and colon .
a resection of the antrum and pars i duodeni with billroth ii reconstruction had to be done due to perforation into the omentum majus .
three days later a hemicolectomy was necessary due to persisting colon distension and serosal disruptions .
due to chronic renal insufficiency recovery was delayed and the patient was dismissed 2 months later . a 48-year - old patient with hemorrhage from esophageal varices
was transferred to our center for a tipss due to persisting bleeding . in the external hospital two upper endoscopies with endoscopic variceal ligation as well as inlay of a linton - nachlas and
consecutively a sengstaken - blakemore balloon catheter had been conducted . besides the patient had been given 8 erythrocyte concentrates , 3 thrombocyte concentrates , 600 ml of fresh frozen plasma as well as coagulation factors ( 3,600 iu prothromplex , see table 1 ) .
soon after arrival at our center the patient developed an abdominal compartment syndrome with quickly increasing difficulties in ventilation and elevated bladder pressure > 20 mm hg .
as a rumenocentesis did not resolve the problem , the patient required an emergent laparotomy . due to worsening liver function with a meld score of 23 and elevated bilirubin ( 102 mol / l ) , tipss implantation was judged to be contraindicated .
the patient needed three surgical revisions , and a repeated gastroscopy showed large esophageal varices , which were treated with rubber band ligation 7 days after admission ( fig .
one week after the compartment syndrome , liver function deteriorated progressively , reaching a maximum meld of 40 probably as the consequence of surgery .
a liver transplantation was discussed and rejected ; we lost the patient due to multi - organ failure .
notably all endoscopies were performed in an emergency room , using ambient air for stomach distension .
all patients were circulatorily compromised with hypotension and needed tracheal intubation for mechanical ventilation and airway protection .
after exclusion of a free perforation and cessation of the endoscopy , the clinical course was benign , allowing a repetition of the endoscopy .
mortality was 40% ( 2/5 patients ) within 30 days , although only in one case ( no .
esophageal variceal bleeding was suggested in a 37-year - old unconscious woman with overt bleeding from the mouth and anus , who was admitted to our emergency room with an initial hemoglobin of 2.7 g / dl and an initial systolic blood pressure of 80 mm hg .
esophageal variceal bleeding was suggested due to the information that the patient had been drinking daily since early youth and that 2 weeks before admission to the emergency room , the patient had had to go to the family doctor because of becoming jaundiced . the model for end - stage liver disease ( meld )
emergency endoscopy was performed directly using a large channel ( 6 mm diameter ) endoscope .
after 1 h of endoscopy , mechanical ventilation became impossible due to an abdominal compartment syndrome .
immediate laparotomy was performed and the stomach had to be evacuated from air and coagula manually with a simultaneously positioned 52-f tube . to stop the ongoing bleeding after coagula evacuation ,
a sengstaken - blakemore balloon was placed . during the first 24 h the patient received 16 erythrocyte concentrates , 2 platelet concentrates , 1,200
ml fresh frozen plasma , 10 g fibrinogen and coagulation factors ( 2,000 iu beriplex , see table 1 , plus 1,250 iu coagulation factor xiii ) .
due to repetitive declines in hemoglobin and the endoscopic proof of bleeding from the esophagus , the patient got a transjugular intrahepatic portosystemic shunt ( tipss ) inadequately lowering the directly measured portal pressure from 46 to 35 mm hg 2 days later .
the patient 's hepatic function , however , remained impaired , the reason why the patient was listed for transplantation on hospital day 5 ( meld score at that time was 29 ) and transplanted on hospital day 12 . today , 2.5 years later , the patient is in good health .
a 56-year - old woman with non - steroidal anti - inflammatory drug ( nsaid ) ( acemetacin 6090 mg ) intake due to chronic polyarthritis was referred to the emergency room with melena and circulatory instability .
the initial hemoglobin value measured in the emergency room was 3.5 g / dl , the initial median arterial pressure was 50 mm hg .
after tracheal intubation , a gastroscopy was started using a 2.8 mm working channel endoscope parallel to an intravenous therapy with a proton pump inhibitor ( 80 mg as bolus followed by 8 mg / h for the next 72 h ) . as a large coagulum filling most of the stomach was detected , the endoscope was exchanged for the large channel endoscope ( 6 mm diameter ) . shortly thereafter , ventilatory problems occurred and a ct scan was immediately arranged presenting extensive meteorism without evidence of perforation .
a second endoscopy was done after exclusion of perforation showing an ulcer with a visible vessel ( forrest iia , fig .
except for meteorism the patient did not suffer from additional symptoms during the following days and was discharged 6 days later .
initially the 83-year - old patient had been transferred to a peripheral hospital , but due to hemodynamic instability he was transferred to our center .
he had been diagnosed with carcinoma of the stomach 1 week before and presented with acute onset of hematemesis and a decline of the hemoglobin value from 9.5 to 6.7 g / dl within a week .
after arrival at our center the hemoglobin had risen to 8.9 g / dl due to the application of two erythrocyte concentrates .
after tracheal intubation a gastroscopy was started . due to large amounts of blood it was switched to the large channel endoscope ( 6 mm diameter ) .
after 5 min the patient developed massive abdominal distension with increasing difficulties of mechanical ventilation .
ct scan showed massive distension of the stomach and small bowel without perforation ( fig .
repeated endoscopy showed an ongoing bleeding near the cardia which could not be stopped ; besides the patient developed an abdominal compartment syndrome with a bladder pressure of 37 mm hg . therefore an emergency laparotomy was performed . at that point
the tumor affected not only the stomach but had also infiltrated the pancreas and colon as well as eroded the splenic artery . due to the only marginal survival chance in case of an extensive surgery and a controlled bleeding at that time , the operation was finished after exploration .
a 78-year - old patient , who was hospitalized due to tachycardic atrial fibrillation and aortocoronary bypass surgery , developed upper gi bleeding on hospital day 9 .
3a ) . despite ulcer treatment with endoclips as well as proton pump inhibitor therapy ,
the patient again developed a bleeding leading to another upper endoscopy 6 days after the first endoscopy . despite revealing an in situ present clip on one of the duodenal ulcers , the endoscopy showed large amounts of blood and coagula in the duodenum ( fig .
the site of bleeding , however , could not be located . within a few minutes , increasing difficulties in the patient 's mechanical ventilation occurred , and increasing norepinephrine requirement from 10 to 50 g / kg / min made an emergency treatment by rumenocentesis necessary .
the immediately performed emergency surgery revealed a massive distension with several serosal disruptions of stomach , small intestine and colon .
a resection of the antrum and pars i duodeni with billroth ii reconstruction had to be done due to perforation into the omentum majus .
three days later a hemicolectomy was necessary due to persisting colon distension and serosal disruptions .
due to chronic renal insufficiency recovery was delayed and the patient was dismissed 2 months later .
a 48-year - old patient with hemorrhage from esophageal varices was transferred to our center for a tipss due to persisting bleeding . in the external hospital two upper endoscopies with endoscopic variceal ligation as well as inlay of a linton - nachlas and consecutively a sengstaken - blakemore balloon catheter had been conducted . besides the patient had been given 8 erythrocyte concentrates , 3 thrombocyte concentrates , 600 ml of fresh frozen plasma as well as coagulation factors ( 3,600 iu prothromplex , see table 1 ) .
soon after arrival at our center the patient developed an abdominal compartment syndrome with quickly increasing difficulties in ventilation and elevated bladder pressure > 20 mm hg .
as a rumenocentesis did not resolve the problem , the patient required an emergent laparotomy . due to worsening liver function with a meld score of 23 and elevated bilirubin ( 102 mol / l ) , tipss implantation was judged to be contraindicated .
the patient needed three surgical revisions , and a repeated gastroscopy showed large esophageal varices , which were treated with rubber band ligation 7 days after admission ( fig .
one week after the compartment syndrome , liver function deteriorated progressively , reaching a maximum meld of 40 probably as the consequence of surgery .
a liver transplantation was discussed and rejected ; we lost the patient due to multi - organ failure .
notably all endoscopies were performed in an emergency room , using ambient air for stomach distension .
all patients were circulatorily compromised with hypotension and needed tracheal intubation for mechanical ventilation and airway protection .
after exclusion of a free perforation and cessation of the endoscopy , the clinical course was benign , allowing a repetition of the endoscopy .
mortality was 40% ( 2/5 patients ) within 30 days , although only in one case ( no .
upper gi bleeding is always a challenging examination for the endoscopist , as affected patients are often instable concerning circulation and need a tracheal intubation before any intervention .
the lumen of the stomach is mostly inadequately prepared for a proper inspection or even therapeutic intervention .
preparation , however , might be optimized by erythromycin applied intravenously before endoscopy , which should therefore be recommended routinely . in all the above reported endoscopies the distension of the stomach , small bowel and even colon generated life - threatening conditions
the emergent endoscopy with different instruments induced an unpredictable amount of air in the gi tract within few minutes examination time , leading to interruption of the procedures , additional examinations like ct scans and even laparotomy .
diagnostic procedures such as ct scan or laparotomy may be avoided by strict suction of the air leaving the endoscope within the stomach . if patients are instable without sufficient oxygenation and the air
has already been distributed all over the gi tract , this strategy may not be an option anymore .
ct scans are of little help in the setting of rapid ballooning of the abdomen because suspected perforation would rather produce peritonism than impressive ballooning .
distended bowel loops may be distinguished from evolving peritonitis following perforation purely by clinical examination .
upper gi endoscopy leading finally to an abdominal compartment syndrome requiring surgery is extremely rare and has , to our knowledge , not been reported to date . in the colon barotrauma , as already mentioned , is rare but well known .
duration of the examination , air trapping due to stenosis in the sigmoid or even argon plasma coagulation therapy leading to an explosion are known causes .
co2 will therefore become standard nowadays ; it is easily available and cheap , and the additional infrastructure is minimal and can be mounted of all types of light sources . in conclusion , we recommend the intravenous application of erythromycin 2030 min in advance of endoscopy to increase visibility and thus reduce endoscopy time .
nevertheless large channel endoscopes have to be used with caution and knowledge about the insufflation power .
co2 insufflation instead of ambient air is wishful and in case of intubated patients , water instead of air should be used as often as possible . in longer - lasting endoscopies
the endoscopist should repetitively palpate the patient 's abdomen to anticipate an abdominal compartment syndrome .
any endoscopist training has to point out the dos and don'ts of an emergency examination . | ### Summary:
: despite the increasing use of carbon dioxide for endoscopies during the last years , ambient air is still used .
the amount of air depends on several factors such as examination time , presumable diameter of the endoscope channel and of course active use of air by the operator .
although endoscopic complications due to ambient air in the gastrointestinal ( gi ) tract are a rare observation and mostly described in the colon , we report five cases in the upper gi tract due to insufflating large amounts of air through the endoscopes .
all 5 patients needed an emergency upper endoscopy for acute presumed upper gi bleeding . in two cases
both esophageal variceal bleeding and ulcer bleeding were detected ; the fifth case presented with a bleeding due to gastric cancer . due to insufflation of inadequate amounts of air through the endoscope channel ,
all patients deteriorated in circulation and ventilation .
two rumenocenteses and consecutively three laparotomies had to be performed in three patients . in the other two , gastroscopies had to be stopped for an emergency computed tomography .
all critical incidents were believed to be a consequence of a long - lasting examination with use of too much air .
therefore in emergency situations , endoscopies should be performed with either submersion , low air flow pumps or even better by the use of carbon dioxide . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: a 36-year - old female smoker presented to the emergency department with epigastric abdominal pain , radiating to her back , of 1 week duration .
her past medical history was significant for type 2 diabetes for which she was on oral hypoglycemic agents and insulin ; presumed secondary htg for which she was on atorvastatin and gemfibrozil ; furthermore , she used medroxyprogesterone acetate for contraception
. she had stopped all these medications except the contraceptive 12 months prior to her presentation .
the patient has no history of alcohol abuse , thyroid dysfunction , or family history of htg . on admission ,
physical examination was normal except for epigastric tenderness and a bmi of 31.4 kg / m .
the initial relevant laboratory testing revealed sodium of 129 meq / l , potassium 3.7 meq / l , chloride 97 meq / l , bun 10 mg / dl , creatinine 0.77 mg / dl ( at baseline ) , bicarbonate 13.7 meq / l , anion gap 18 meq / l , glucose of 324 mg / dl , amylase 31 iu / l , lipase 206 iu / l , and tg 2,329 mg / dl with a previous baseline of around 2,000 mg / dl , serum calcium 9.0 mg / dl , tsh 1.182 iu / ml , serum lactate 1.8 meq / l , negative urine ketones with serum beta - hydroxybutyrate 0.16 mmol / l , and negative urine pregnancy test .
the abdominal computerized tomography scan showed no definite evidence of pancreatitis or any other pathology . despite unremarkable imaging , normal amylase , mild elevation of lipase , and a tg level that was mildly elevated from previous baseline ,
she was treated for possible htgp with iv insulin based on the overall clinical picture .
the differential diagnosis includes diabetic ketoacidosis ( dka ) ; however , the patient lacked serum or urinary ketones .
the clinical impression of htgp was further supported when her lipase increased to 370 iu / l and the tg levels on the initial sample was re - assayed resulting in a corrected reading of > 10,000 mg / dl .
the tg levels decreased to 6,069 mg / dl with iv insulin on day 5 .
however , given the worsening abdominal pain , plan for plasmapheresis to rapidly reduce the tg levels was taken .
the tg levels decreased to 2,055 mg / dl after the first exchange and to 642 mg / dl after the second session , and her symptoms improved significantly .
htg is defined as fasting tg levels greater than 150 mg / dl and levels exceeding 1,000 mg / dl is defined as severe htg ( 1 ) .
use of injectable and oral contraceptives containing estrogen have been associated with htg , but use of medroxyprogesterone , as in our patient , has not been associated with htg ( 3 ) . the exact mechanism by which severe htg precipitates acute pancreatitis remains unknown , and various theories have been postulated ( 2 ) .
htgp should be suspected with severe htg and clinical picture consistent with acute pancreatitis , which is established when two of the following three findings are present : epigastric abdominal pain ; elevated serum enzyme , three or more times the upper limit of normal ; or radiologic imaging consistent with acute pancreatitis ( 4 ) .
our patient had various spurious laboratory abnormalities including normal amylase levels , pseudohyponatremia , and falsely low tg levels compared with the repeat testing on the same initial sample which was consistent with few previously reported cases ( 5 , 6 ) .
normal amylase levels can be present in patients with tg levels above 500 mg / dl due to interference with the calorimetric reading .
tg interference is due to anaerobic conditions associated with grossly lipemic plasma disrupting the enzymatic reactions associated with tg assays , which considerably underestimate the final value of tg concentrations .
the solution for samples with surprisingly low results is to re - assay after diluting or using a smaller volume of sample ( 6 ) .
although our patient had high lipase levels , there is literature on cases of htgp patients with normal lipase levels(5 ) , the reason being unknown ( 4 ) . to the best of our knowledge ,
this is the second case in literature where falsely low tg levels were present on admission requiring repeated laboratory testing on the same initial sample for accurate results . the previously described case by markota et al . ( 7 ) presented with falsely low tg levels and was treated with plasma exchange due to worsening clinical status and evidently lipemic serum . treatment of htgp aims at reducing the tg levels with the use of iv insulin and plasmapheresis ( 8) .
although a number of falsely low lab values ( amylase , tg ) were noted in our patient , the overall clinical impression of pancreatitis with history of elevated tg levels , iv insulin was started .
although , the tg levels decreased by 30% , at 72 hours of treatment , due to worsening abdominal pain , rapid reduction in tg levels by therapeutic plasma exchange was undertaken . in summary ,
our case highlights the importance of being cognizant of falsely low amylase and tg levels that can be present in patients with htgp .
hence , it is suggested that the diagnosis of htgp be considered in patients with history of elevated tg and clinical picture consistent with pancreatitis , despite the presence of confounding laboratory abnormalities ( falsely low amylase and tg ) .
the authors have not received any funding or benefits from industry or elsewhere to conduct this study . | ### Summary:
: we present the case of a 36-year - old woman who presented to our hospital with epigastric abdominal pain and tenderness .
laboratory evaluation identified high lipase , normal amylase , pseudohyponatremia , and relatively falsely low triglyceride levels ( initial value of 2,329 mg / dl which on repeat was found to have corrected value of > 10,000 mg / dl ) .
the overall clinical picture was consistent with acute pancreatitis due to hypertriglyceridemia .
the patient was commenced on iv insulin and eventually required plasmapheresis with good clinical outcome .
this case highlights the importance of being cognizant of falsely low amylase and tg levels that can be present in patients with hypertriglycereidemic pancreatitis |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: dramatic demographic and epidemiological changes over the past few decades have transformed the world 's health care needs , making long - term care for the frail elderly and younger people with chronic and disabling conditions , a major policy issue particularly in developed countries .
the sheer size of this population , coupled with its growing needs , has prompted the expansion of publicly funded home and community - based services . nonetheless , persistent cost - effectiveness and quality concerns have stimulated interest in a continuum of other long - term care solutions .
the rubric of reform includes integrated models of care with agency / professionally managed service packages , often with pooled financing , on one end , and consumer - directed approaches that give recipients of home and community services more power over arranging and directing their own care , on the other .
consumer - directed home care programs are found in various forms in europe and north america , even in countries where more integrated approaches to service co - ordination and care management are being simultaneously studied or developed .
the growing experience with consumer - directed services suggests that it is not only a valuable model in its own right . despite appearances to the contrary ,
the know - how from consumer directed services could also make integrated care work better .
this article first explores the meaning , rationale and models of consumer - directed care.1 this is followed by an analysis of developments , designs and experiences of select programs in austria , germany , the netherlands , and the united states ( us ) .
the article concludes with an examination of the lessons learned from these programs and their implications for building more responsive and effective integrated care systems for the frail elderly and people with chronic disabilities .
people with disabilities depend largely on the help of others to function in their daily lives . while families represent a major source of support , an increasing amount of help with activities of daily living ( adl ) such as bathing , dressing and eating , and instrumental activities of daily living ( iadl ) such as cooking , shopping and housekeeping is provided by workers from publicly funded home care agencies .
although mounting reliance on formal or agency - provided services has enabled growing numbers of disabled persons ( the majority of which are the frail elderly ) to remain at home , these individuals often lose control over their own lives in a case - managed system where virtually all decisions over the what , who , and when of home and community care become the responsibility of professional and paraprofessional workers . the consumer - directed philosophy and approach are designed to maximise the autonomy and independence of persons with physical dependencies by giving them greater choice and control over personal care and other in - home services and providers . depending on the model
, consumers can be empowered to assume responsibility for key decisions , including assessment of their own needs , determination of how and by whom needed services should be delivered , and monitoring the quality of services received . by emphasising privacy , autonomy and the right to
manage one 's own risk , consumer - direction is seen as a way of levelling the playing field between institutional and home- and community - based care . the ideas behind consumer - directed care allowing people to have control and autonomy over their own lives , and respecting the personal choices they make are not new .
they reflect basic humanistic values found in most cultures , and also form the ethical basis for the helping professions such as medicine , nursing and social work .
be that as it may , consumer - directed care is also a reaction to the increasingly managerial culture of health and social care , wherein services are delivered according to the dictates of bureaucrats and professionals and consumer views are given short shrift or rarely addressed .
critics of the traditional agency model , at least in the us , argue that the long - term care system , whether institutionally- or community - based , provides little opportunity for persons with physical disabilities to shape and direct their own care , despite the fact that most supportive services delivered at home are low - tech , non - medical and do not require extensive training or oversight . furthermore , there is criticism that home care agencies make consumers take a
consequently , all manner of decisions affecting client access , satisfaction and quality of care major tasks such as service planning , worker tasking , assignment , and scheduling , and ongoing monitoring of performance are taken with little , if any regard for the preferences of recipients or are otherwise predisposed by an unyielding regulatory system .
the roots of the consumer - directed approach are found in the decades - old advocacy movements among working - age people with disabilities in the us and western europe .
these consumer movements have not only been successful in demanding the de - medicalisation and de - institutionalisation of services , but also in the development of options fostering greater self - determination , more freedom of choice and less professional and state involvement in the daily lives of people with disabilities [ 5 , 10 ] .
similar views , at least in the american context , are slowly but surely taking hold among the elderly .
first , government is more receptive to consumer - directed care , because it promises the reduction or elimination of costly home care agencies and care managers .
second , concern about the shortage of front - line home care personnel has opened policymakers to the possibility that the strategy might help with recruitment of new workers by its tapping into the grey market ( e.g. family , friends and neighbours ) .
third , the growing importance of chronic illness management in the overall health system is driving more activated patients to play a more central role in their own care , thus potentially enhancing the importance of consumer - directed services at home . despite the positive rationale ,
doty , benjamin , matthias and franke suggest that agency - managed services may produce better outcomes because of the importance that professional supervision plays in quality care .
client capacity for independent decision - making , liability related to poor service outcomes ( e.g. health status and quality of care ) , and accountability for the use of public funds are also frequently mentioned issues [ 14 , 15 ] .
benjamin , egley , and tilly and wiener point out that consumer - directed care is not a single approach , but constitutes an array of models differing in terms of the level and type of decision - making , autonomy and control vested in the client vs. the home care agency and/or public long - term care system .
moreover , programs vary in key areas such as functional and financial eligibility , covered services , benefit limits , hiring restrictions ( e.g. family members ) , administrative structure , and funding source ( i.e. social insurance or general revenues ) . roughly speaking ,
however , recipients receive mandated guidance from care managers , who are also responsible for monitoring services over time according to an approved care plan.professionally assisted model .
care managers initially determine program eligibility and approve service hours , but decisions regarding hiring , scheduling , supervision and termination of workers are left to the client .
clients receive periodic cash allotments and are given total discretion with respect to purchasing virtually any services or goods they deem essential .
however , recipients receive mandated guidance from care managers , who are also responsible for monitoring services over time according to an approved care plan .
care managers initially determine program eligibility and approve service hours , but decisions regarding hiring , scheduling , supervision and termination of workers are left to the client .
professional help with key tasks may also be provided in some programs . cash model .
clients receive periodic cash allotments and are given total discretion with respect to purchasing virtually any services or goods they deem essential .
several options are available to pay workers in the professionally monitored and professionally assisted models .
in addition to direct payment by the public authority or the use of so - called vouchers to obtain services , clients may also be given the choice of managing cash on their own , or opting to have a certified fiscal agent to perform this function .
furthermore , the professionally assisted and cash models may incorporate various counselling services to help the client assess personal preferences and the ability to self - direct , as well as to identify , screen and train prospective workers .
as indicated earlier , consumer - directed programs for the elderly and people with disabilities , including payments for informal caring , are growing in importance in developed nations [ 1821 ] .
the following is a brief review of the programs and experiences in four countries , three in europe ( austria , germany and the netherlands ) and one in north america ( us ) .
the resulting social insurance - based system is administered by the regional health insurance funds .
the program , which provides non - means tested cash benefits to eligible clients and replaces previously existing provincial attendance allowances , is designed to help recipients pay for care expenses , enable them to remain at home , and promote self - determination and family support .
recipients must be at least three years old , permanently in need of personal assistance , and require 50 hours of care or more on a monthly basis . in the case of
cognitively impaired individuals , someone must be appointed to manage the allowance . in 1994 , there were seven benefit levels ranging from monthly cash payments of us$ 250 to us$ 2,000 .
the results of their mail survey , which included 3120 respondents approximately 75% of whom were age 65 and over , is summarised by tilly and bectel .
eighty - one percent of the survey respondents reported using their care allowance to compensate family members , and nearly a third used the cash they received to perform home modifications .
more than 70% of these individuals indicated that the care allowance better equipped them than previously to deal with the pressures of daily living , and 65% reported greater freedom in selecting carers . before 1994 , germany 's system of state support for long - term care was institutionally - biased , means - tested and administered at the provincial level by the states ( lnder ) [ 26 , 27 ] .
three main issues led to the enactment of legislation in that year creating a universal social insurance program for long - term care : ( 1 ) the then increasing fiscal pressures on the states ; ( 2 ) a growing sense that the german notion of social solidarity was being compromised by the old means - tested system ; and , 3 ) the belief that the supply and quality of services were being eroded [ 28 , 29 ] .
germany 's program , which is similar to the austrian entitlement and known as social dependency insurance ( in german , sociale pflegeversicherung ) , is funded through a mandatory , income - related payroll tax .
the system , which gives priority to care at home over that in a nursing home , became operational between april 1995 ( for home care ) and july 1996 ( for institutional care ) .
beneficiaries can receive needed in - home care in the form of in - kind services , cash , or a combination of both . responsibility for administering this non - means tested coverage
benefits are made available to persons regardless of age who meet the minimum functional eligibility criteria ( i.e. need for assistance with at least 2 adls and some iadls ) .
the amount of cash received depends on the recipient 's level of severity , and ultimately represents about 50% of the value of comparable in - kind services .
although the beneficiary is free to use funds for any services desired , cuellar and wiener find that there are no mechanisms available to assist them in making choices , allocating services based on need , or providing information and referral to supportive services .
runde et al . examined the early experience of program participants , which included 10,400 respondents to a mail survey , three - quarters of whom were age 65 and over .
tilly and bectel 's excellent summary of this research , reports that 71% of the respondents believed the program helped to preserve their independence ; 85% of the cash assistance recipients and 61% of the combination - benefit recipients participating in the survey also saw a major benefit in being able to use funds as they wished .
in addition , 43% of the respondents felt that the quality of their care had actually improved , with another 55% indicating that the level of quality remained about the same .
a care initiative known as the person - centred budget ( in dutch , persoonsgebondenbudget ) was introduced in 1995 by the government of the netherlands .
initially established as a demonstration , this cash assistance program was designed to promote greater choice and higher quality of care for consumers , as well as to encourage increased competition among providers .
cash payments , which are financed through the country 's exceptional ( i.e. catastrophic ) medical expense insurance program ( in dutch , algemene wet bijzondere ziektekosten , or awbz ) , enable eligible clients to purchase primarily adl- and iadl - related services from the provider of their choice , including informal carers or agencies from the regulated or private markets ; a small amount is set aside for flexible use .
younger individuals and those with cognitive impairments must have a surrogate decision - maker to participate . each client 's monthly benefit level is determined by multiplying the hours in a professionally developed care plan by standard , national rates ; income - related deductions are then taken .
first , participants in a randomised control trial conducted by miltenburg and colleagues during the initial demonstration phase indicated that they had more control over services than individuals in the comparison group with traditional agency - provided services .
second , in a quasi - experimental study conducted several years after the dutch program 's national implementation , woldringh and ramakers found several important participant outcomes , namely significantly more choice of , and influence and control over their services , as compared to matched controls receiving agency - provided care .
more and more american states have incorporated consumer - directed features into their home care programs . unlike the previously discussed european cash assistance programs , however , these efforts fall mainly into the professionally monitored or professionally assisted models described earlier [ 8 , 17 ] .
the us department of health and human services , with the support of the robert wood johnson foundation , however , is testing a cash model with a counselling component in three states ( arkansas , florida and new jersey .
space does not permit description and discussion of the large number of consumer - directed efforts found in the us.2 suffice to say , these programs are means - tested and provide largely adl / iadl assistance , but otherwise differ in terms of goals ( e.g. client empowerment , improved care , and/or cost control ) , functional eligibility , benefit amounts , level of care management involvement , quality assurance , availability of worker training , and administrative responsibility .
depending on the particular program , financing comes from one or more of the following public sources : medicaid , older americans act , and state and county funds.3 there is a growing body of evidence on various aspects of the us experience with consumer - directed services . the following briefly summarises three large - scale reviews by doty et al . ,
tilly and wiener , and tilly and wiener on the results of initiatives in several states ( california , colorado , kansas , maine , michigan , oregon , washington and wisconsin ) .
when the work of these researchers are taken together , they result in a number of important overall conclusions : first , clients who self - direct their own care have more control and express greater satisfaction over the services they choose .
second , participants in these state programs perceived either that quality improved as a result of consumer direction or at least did not suffer vis - - vis agency - provided care .
third , the use of independent home care workers , including family members , was frequently associated with increased hours of service per participant , as well as lower total costs of in - home care .
the emerging experience in arkansas , one of the three states taking part in the aforementioned federal demonstration of cash and counselling , suggests that this particular model
akin to efforts in austria , germany and the netherlands offers several other important benefits . according to recent findings , clients involved in the program were less likely than control group members to have unmet needs
; were at least as safe from adverse events and health problems as participants receiving traditional , agency - directed services ; and , were more likely to be satisfied with life than the controls .
the resulting social insurance - based system is administered by the regional health insurance funds .
the program , which provides non - means tested cash benefits to eligible clients and replaces previously existing provincial attendance allowances , is designed to help recipients pay for care expenses , enable them to remain at home , and promote self - determination and family support .
recipients must be at least three years old , permanently in need of personal assistance , and require 50 hours of care or more on a monthly basis . in the case of cognitively impaired individuals
, someone must be appointed to manage the allowance . in 1994 , there were seven benefit levels ranging from monthly cash payments of us$ 250 to us$ 2,000 .
the results of their mail survey , which included 3120 respondents approximately 75% of whom were age 65 and over , is summarised by tilly and bectel .
eighty - one percent of the survey respondents reported using their care allowance to compensate family members , and nearly a third used the cash they received to perform home modifications .
more than 70% of these individuals indicated that the care allowance better equipped them than previously to deal with the pressures of daily living , and 65% reported greater freedom in selecting carers .
before 1994 , germany 's system of state support for long - term care was institutionally - biased , means - tested and administered at the provincial level by the states ( lnder ) [ 26 , 27 ] .
three main issues led to the enactment of legislation in that year creating a universal social insurance program for long - term care : ( 1 ) the then increasing fiscal pressures on the states ; ( 2 ) a growing sense that the german notion of social solidarity was being compromised by the old means - tested system ; and , 3 ) the belief that the supply and quality of services were being eroded [ 28 , 29 ] .
germany 's program , which is similar to the austrian entitlement and known as social dependency insurance ( in german , sociale pflegeversicherung ) , is funded through a mandatory , income - related payroll tax .
the system , which gives priority to care at home over that in a nursing home , became operational between april 1995 ( for home care ) and july 1996 ( for institutional care ) .
beneficiaries can receive needed in - home care in the form of in - kind services , cash , or a combination of both . responsibility for administering this non - means tested coverage
benefits are made available to persons regardless of age who meet the minimum functional eligibility criteria ( i.e. need for assistance with at least 2 adls and some iadls ) .
the amount of cash received depends on the recipient 's level of severity , and ultimately represents about 50% of the value of comparable in - kind services .
although the beneficiary is free to use funds for any services desired , cuellar and wiener find that there are no mechanisms available to assist them in making choices , allocating services based on need , or providing information and referral to supportive services .
runde et al . examined the early experience of program participants , which included 10,400 respondents to a mail survey , three - quarters of whom were age 65 and over .
tilly and bectel 's excellent summary of this research , reports that 71% of the respondents believed the program helped to preserve their independence ; 85% of the cash assistance recipients and 61% of the combination - benefit recipients participating in the survey also saw a major benefit in being able to use funds as they wished .
in addition , 43% of the respondents felt that the quality of their care had actually improved , with another 55% indicating that the level of quality remained about the same .
a care initiative known as the person - centred budget ( in dutch , persoonsgebondenbudget ) was introduced in 1995 by the government of the netherlands . initially established as a demonstration ,
this cash assistance program was designed to promote greater choice and higher quality of care for consumers , as well as to encourage increased competition among providers .
cash payments , which are financed through the country 's exceptional ( i.e. catastrophic ) medical expense insurance program ( in dutch , algemene wet bijzondere ziektekosten , or awbz ) , enable eligible clients to purchase primarily adl- and iadl - related services from the provider of their choice , including informal carers or agencies from the regulated or private markets ; a small amount is set aside for flexible use .
younger individuals and those with cognitive impairments must have a surrogate decision - maker to participate . each client 's monthly benefit level is determined by multiplying the hours in a professionally developed care plan by standard , national rates ; income - related deductions are then taken .
first , participants in a randomised control trial conducted by miltenburg and colleagues during the initial demonstration phase indicated that they had more control over services than individuals in the comparison group with traditional agency - provided services .
second , in a quasi - experimental study conducted several years after the dutch program 's national implementation , woldringh and ramakers found several important participant outcomes , namely significantly more choice of , and influence and control over their services , as compared to matched controls receiving agency - provided care .
more and more american states have incorporated consumer - directed features into their home care programs . unlike the previously discussed european cash assistance programs , however , these efforts fall mainly into the professionally monitored or professionally assisted models described earlier [ 8 , 17 ] . the us department of health and human services , with the support of the robert wood johnson foundation , however , is testing a cash model with a counselling component in three states ( arkansas , florida and new jersey .
space does not permit description and discussion of the large number of consumer - directed efforts found in the us.2 suffice to say , these programs are means - tested and provide largely adl / iadl assistance , but otherwise differ in terms of goals ( e.g. client empowerment , improved care , and/or cost control ) , functional eligibility , benefit amounts , level of care management involvement , quality assurance , availability of worker training , and administrative responsibility . depending on the particular program , financing comes from one or more of the following public sources : medicaid , older americans act , and state and county funds.3 there is a growing body of evidence on various aspects of the us experience with consumer - directed services .
the following briefly summarises three large - scale reviews by doty et al . , tilly and wiener , and tilly and wiener on the results of initiatives in several states ( california , colorado , kansas , maine , michigan , oregon , washington and wisconsin ) .
when the work of these researchers are taken together , they result in a number of important overall conclusions : first , clients who self - direct their own care have more control and express greater satisfaction over the services they choose .
second , participants in these state programs perceived either that quality improved as a result of consumer direction or at least did not suffer vis - - vis agency - provided care .
third , the use of independent home care workers , including family members , was frequently associated with increased hours of service per participant , as well as lower total costs of in - home care .
the emerging experience in arkansas , one of the three states taking part in the aforementioned federal demonstration of cash and counselling , suggests that this particular model
akin to efforts in austria , germany and the netherlands offers several other important benefits . according to recent findings , clients involved in the program were less likely than control group members to have unmet needs ; were at least as safe from adverse events and health problems as participants receiving traditional , agency - directed services ; and , were more likely to be satisfied with life than the controls .
consumer direction represents an important strategy to enhance access to , and the quality of , home and community services for the disabled population in need of long - term care .
our review of consumer - directed home care programs in austria , germany , the netherlands , and the us , as well as findings from research studies undertaken in these countries , support the belief that the frail elderly and younger persons with disabilities would experience a better quality of life if such programs were made more widely available .
not everyone wishes or has the capacity to manage his or her own care ( e.g. persons with cognitive impairment and some of the frail elderly ) .
irrespective of the models implemented , they provide recipients with more choice and control in everyday living , help to ensure greater flexibility in services , produce a higher level of satisfaction and well being , and may be more cost - efficient than agency - directed care .
consumer - directed philosophy and methods offer a potentially powerful tool to remake care of the elderly and persons with disabilities or chronic conditions . but are consumer - directed care and integrated care antithetical ?
more specifically , should and can we incorporate consumer - directed approaches in emerging integrated care models ? this is an important issue , because integrated systems of care tend to concentrate managerial responsibility and , thus monopolise consumer control , in order to produce the much hoped for end - results of co - ordination , continuity , and cost - effectiveness .
active discussion of this issue and early experimentation with hybrid models has already begun in the us .
american experts are somewhat divided with respect to the need to combine , and the compatibility between , these two approaches .
according to a study by simon - rusinowitz and colleagues , many of the policy experts they interviewed believe that the prevailing medical ethic and obvious tensions between consumerism and managerial / clinical control would present major obstacles to the creation of self - directed managed or integrated care models
. however , kodner and kay kyriacou , stone , kodner , mahoney and raphael , kodner , sherlock and shankman , and meiners et al .
demonstrate that integrated systems of care can be fertile ground for consumer - driven services .
these authors maintain that such options could humanise integrated care by encouraging more flexible service use and greater consumer satisfaction and quality without harming inherent efficiency and effectiveness goals .
a broad array of approaches or methods is available to encourage and support personal choice , control and self - direction in integrated systems of care :
new programs could be designed with the active participation of prospective clients and carers in the targeted risk group . in addition , structures could be incorporated into the design to either share program ownership with clients or at the very least assure that their voices are clearly heard on the administrative , clinical and service delivery levels.staff development could focus on the recruitment of team members who respect the philosophy of client empowerment .
training could also be developed to help staff overcome the traditional health care mindset with its tendency to dismiss active consumer involvement .the use of value - driven assessment tools could assist clients and family carers in articulating goals , preferences and expectations from their own perspectives , thus allowing for more personalised , consumer - sensitive and client - driven care .information and education services could be provided to enhance the client 's capacity to make more informed decisions about service needs and choices .clients could be given more control over provider selection , as well as the scheduling of services . or , more extensive consumer - directed options could be offered , ranging from the use of vouchers to cashing out benefits with or without the involvement of counsellors or professional care managers .
the positive experiences associated with the latter approach have been described extensively in this article.the incorporation and use of technology in integrated systems of care could greatly enhance the quality of client - provider communications , as well as consumer - directed information and decision - making , thus making empowerment easier to achieve .
new programs could be designed with the active participation of prospective clients and carers in the targeted risk group .
in addition , structures could be incorporated into the design to either share program ownership with clients or at the very least assure that their voices are clearly heard on the administrative , clinical and service delivery levels .
staff development could focus on the recruitment of team members who respect the philosophy of client empowerment .
training could also be developed to help staff overcome the traditional health care mindset with its tendency to dismiss active consumer involvement .
the use of value - driven assessment tools could assist clients and family carers in articulating goals , preferences and expectations from their own perspectives , thus allowing for more personalised , consumer - sensitive and client - driven care .
information and education services could be provided to enhance the client 's capacity to make more informed decisions about service needs and choices .
clients could be given more control over provider selection , as well as the scheduling of services . or , more extensive consumer - directed options could be offered , ranging from the use of vouchers to cashing out benefits with or without the involvement of counsellors or professional care managers .
the positive experiences associated with the latter approach have been described extensively in this article .
the incorporation and use of technology in integrated systems of care could greatly enhance the quality of client - provider communications , as well as consumer - directed information and decision - making , thus making empowerment easier to achieve . to be successful
, integrated care programs must do a better job of managing services and costs for disabled and chronically ill persons than the disjointed systems of health and social care they are intended to replace .
this can only be accomplished by reconciling two seemingly conflicting perspectives , namely , the commitment to professional dominance and managerial efficiency , and the legitimate claims of client autonomy and self - direction . with mounting evidence on the advantages and positive effects of consumer direction , a strong case can and should be made for the integration of this innovative idea and approach into emerging models of integrated provision for people with disabling or chronic conditions in need of long - term care .
whether such initiatives are targeted to working - age or elderly populations , policy makers , planners and service managers would do well to encourage the design of programs and packages of care that incorporate as many of the above features as possible .
further research would also be helpful in establishing the cost - effectiveness of the various consumer - directed models , and in studying how they specifically perform within the framework of integrated service delivery . | ### Summary:
: abstractover the past decade , policy makers in developed countries have begun to pay increasing attention to reform of the long - term care system for the frail elderly and younger people with disabilities .
a continuum of strategies have generated interest , including integrated systems of care with agency / professionally managed service packages on the one end , and programs offering cash benefits along with the flexibility to decide how to best use these funds to meet individual needs and preferences , on the other .
the latter approach , known as
consumer - directed care , is found in various forms and degrees in europe and north america .
primarily organised around the provision of home and community care , consumer - directed services are aimed at empowering clients and family carers , giving them major control over the what , who and when of needed care .
consumer - directed care appears to be the antithesis of integrated care .
however , it actually holds important lessons and implications for the latter .
this policy paper explores the rationale and models of consumer - directed services at home , reviews developments , designs and outcomes of programs in the austria , germany , the netherlands , and the us .
it also discusses how this experience could be helpful in shaping better and more responsive integrated models of care for vulnerable long term care populations . |
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: preterm labour < 34 weeks occurs in about 4% of pregnancies . in 8085% of cases of spontaneous preterm labour ( ptl )
< 28 weeks , there is evidence of intrauterine infection . despite increased awareness of the association between inflammation and preterm labour ,
there have been no major advances in the prevention of preterm labour which have been shown to improve long - term neonatal outcomes . during normal term labour ,
the uterus and cervix become infiltrated with leukocytes and undergo changes in response to local secretion of proinflammatory cytokines .
a similar pattern of biochemical events occur during ptl ; however , the triggers for this premature activation are still not fully understood .
regardless , the presence of increased proinflammatory cytokines during pregnancy is clearly associated with a poor prognosis for babies born preterm .
the former is a nonspecific system providing immediate defence against pathogens , while the latter is more targeted , characterised by t and b lymphocytes .
although cross - talk between these lymphocytes exist , b cells and their antibodies mainly give rise to humoral immunity , whereas t cells primarily provide cell mediated immunity .
t helper cells ( cd4 ) form a subset of t cells and can be further subdivided into t helper 1 cells ( th1 ) and t helper 2 cells ( th2 ) depending on their pattern of cytokine production .
th1 cells secrete pro inflammatory cytokines such as interferon gamma ( ifn- ) and tumor necrosis factor alpha ( tnf- ) , whereas the th2 cells secrete anti - inflammatory cytokines such as interleukin 4 ( il-4 ) , il-10 , and il-13 . a mutually exclusive interaction exists between the th1 interleukin , ifn- , and the th2 interleukin , il-4 .
il-4 is the dominant factor for promoting growth and differentiation from the th0 to the th2 subtype , and directly inhibits the development of the th1 cells .
ifn- indirectly promotes th1 differentiation by upregulating the il-12 receptor whilst inhibiting the growth of th2 cells [ 8 , 9 ] .
wegmann and colleagues first developed the concept that during pregnancy there is a shift from a t helper 1 ( th1 ) response to a t helper 2 ( th2 ) bias during pregnancy that functionally induces maternal tolerance and suppression .
consistent with this notion , administration of the th1 interleukins ifn- and il-2 leads to fetal loss and preterm labour in the mouse .
similarly , cba dba/2 mice that have placentas deficient in il-4 and il-10 are prone to fetal resorption .
several human studies have shown a th2 bias in the ratio of circulating t helper cytokine profile in normal pregnancy ; and an increase in the th1 ratio in cases of recurrent miscarriage and in preeclampsia .
peripheral blood lymphocytes taken from women in the first trimester show an increased production of il-4 and il-10 and less ifn- compared to nonpregnant controls in vitro .
there is in vivo evidence in pregnant women of increased expression of il-4 messenger ribonucleic acid ( mrna ) and lower expression of the ifn- mrna .
not all studies support the requirement of the shift from th1 to th2 for successful pregnancy outcome [ 18 , 19 ] . despite showing a suppression of ifn- and an increase in il-10 during pregnancy compared to nonpregnant controls ,
. showed no difference in ifn- , il-10 , or il-4 secretion in women who subsequently miscarried compared with those who went on to complete their pregnancy .
however , contrary to this study , women with recurrent miscarriage have been shown to have increased ifn- and tnf- levels compared with women that go on to have successful pregnancies . while the mechanism regulating the th1 : th2 ratio is yet to be fully elucidated the importance of maternal immune tolerance during pregnancy is unquestionable .
several pregnancy - related proteins are known to promote th2 bias such as leukemia inhibitory factor , progesterone , progesterone - induced blocking factor , and estradiol .
prostaglandin d2 ( pgd2 ) promotes il-4 , il-13 , il-5 , and il-10 production in t helper 2 cells in vitro via the second pgd2 receptor ; chemoattractant receptor - homologous molecule expressed on th2 cells ( crth2 ) .
pgd2 is produced by the placenta and may play a role in the chemoattraction of th2 cells via the crth2 receptor to the maternal fetal interface to produce a localised th2 bias .
15-deoxy--prostaglandin j2 ( 15dpgj2 ) , an endogenous prostaglandin ( pg ) , is a product of pgd2 via a series of dehydration reactions .
as well as being a ligand for peroxisome proliferator - activated receptor gamma ( ppar ) , it is also an agonist of the crth2 receptor .
we have previously demonstrated that this anti - inflammatory pg inhibits nuclear factor kappa b ( nf-b ) in amniocytes and myocytes in vitro and delays infection induced preterm labour and increases pup survival in the mouse via nf-b inhibition .
moreover , recent work has shown that the first trimester of pregnancy is associated with the suppression of available t cell nf-b and reduced levels of ifn- compared to nonpregnant controls [ 30 , 31 ] .
collectively these data suggest that the th1 : th2 ratio is modulated through the regulatory interplay of both th1 suppression and th2 promotion . in this study , we examined the expression of the dominant th1 interleukins ifn- and tnf- , and the th2 interleukin il-4 in t helper cells obtained from nonpregnant women , women in the early and late third trimester , and during labour .
we examined the effect of the crth2 agonist , 15dpgj2 , on these interleukins and on nf-b activation at different gestational time points to determine its potential role in suppressing the th1 response via nf-b whilst simultaneously promoting the th2 response via crth2 .
pregnant women at 28 weeks and term ( prelabour and in labour ) and nonpregnant women of child bearing age were included in the study in accordance with ethical approval from the south east london ethical committee ref .
exclusion criteria included women with asthma and hiv , women not of childbearing age , and women with a fever .
after obtaining informed consent , 5 ml of peripheral venous blood was collected in sodium citrate tubes , and processed within 30 mins of collection . unless otherwise stated , a minimum of 4 subjects were included for each experimental sample group .
blood was diluted 1 : 1 with phosphate - buffered saline ( pbs ) and carefully layered onto ficoll - paque plus ( ge healthcare , uppsala , sweden ) before centrifuging at 400 g for 40 mins at room temperature . after centrifugation , the halo containing pbmcs was carefully transferred into a clean centrifuge tube and washed twice with 7 ml of pbs .
after centrifugation ( 400 g for 10 mins ) , the cell pellet was resuspended in either pbs or rpmi 1640 ( invitrogen life technologies , grand island , ny , usa ) culture medium .
the pbmc pellet was resuspended pbs , and cells were counted with a neubauer haemocytometer and then resuspended in staining buffer ( 1% fetal calf serum ; 0.09% sodium azide in pbs ) to obtain roughly 3.5 10 cells per sample .
preparations were incubated in the dark for 1 h at 37c with 20 l of crth2-phycoerythrin ( crth2-pe ) ( beckman coulter , high wycombe , uk ) and 3 l of cd4-allophycocyanin ( cd4-apc ) ( bd pharminogen , oxford , uk ) or the relevant isotype controls ; rat immunoglobulin ( ig)g2a - pe ( beckman coulter ) and mouse igg1-apc ( bd pharminogen ) .
after incubation , the pbmc suspension was washed twice in 1 ml of pbs and then resuspended in pbs for analysis .
flow cytometry settings were as follows : forward scatter e0 voltage , 1.00 amp gain lin , and side scatter of 329 voltage , 1.00 amp gain lin .
a total of 50,000 cells were counted and gating was on lymphocytes based on the forward and side scatter . for intracellular cytokine studies
, cells were resuspended in rpmi 1640 ( invitrogen ) media supplemented with 10% fetal calf serum , 2 mm / l l - glutamine , 100 u / ml penicillin , and 100 g / ml of streptomycin ( sigma , st .
louis , mo , usa ) before being plated in 24-well plates and incubated for 18 h in 5% co2/humidified air at 37c . following this ,
10 g of brefeldin a ( sigma ) was added to each well to immobilize the interleukins in the golgi apparatus .
cells were pretreated with 32 m of 15dpgj2 ( cayman chemicals , ann arbor , mi , usa ) or dimethyl sulfoxide ( dmso ) ( sigma ) vehicle control for 2 h in the case of ifn- and tnf- experiments or 1 h for il-4 . following this 50 ng / ml of phorbol myristate acetate ( pma ) and 0.5
g / ml of ionomycin were added for 4 h in the case of ifn- and tnf- experiments or 5 h for il-4 .
prior to intracellular staining , cell surface staining with either crth2 and cd4 , or cd4 antibodies alone , was performed as described in section 2.3 .
cells were then fixed with 2% paraformaldehyde ( pfa ) and incubated at 37c for 15 mins in the dark .
cells were washed and resuspended in 0.5% saponin and incubated for 30 mins on ice in the dark to permeabilize the cells .
after incubation , cells were washed and resuspended in 0.5% saponin for intracellular staining with the relevant antibody ; il-4 pe / cy7 ( biolegend , san diego , ca , usa ) , ifn--(fluorescein isothiocyanate ( fitc ) or tnf--fitc ( bd biosciences , franklin lakes , nj , usa ) .
appropriate isotype controls were used ; pe / cy7 rat igg1 ( biolegend ) , or fitc mouse igg1 ( bd biosciences , oxford , uk ) .
cells were incubated in the dark for 1 h at room temperature for il-4 staining or 20 mins on ice for ifn- and tnf- staining .
finally , cell suspensions were washed with 0.5% saponin and resuspended in pbs for flow cytometry analysis as follows : forward scatter e0 voltage ; 1.00 amp gain lin ; side scatter of 329 voltage ; 1.00 amp gain lin .
flow cytometry of lymphocytes was carried out using facscalibur flow cytometer ( bd biosciences ) equipped with facscalibur software for analysis .
the lymphocyte population was gated on the scatter plot as determined by the characteristic forward scatter ( fs ) and side scatter ( sc ) which indicates the cell size and shape .
the analysis was of cd4 , crth2 , and crth2/cd4 in the crth2 expression studies and il-4 , il-4/crth2 , tnf-/cd4 , and ifn-/cd4 for the intracellular cytokines .
the expression levels of crth2 , cd4 , and intracellular cytokines were evaluated by the percentage of cells expressing the protein of interest or by mean fluorescence intensity ( mfi ) . following culture and treatments ,
cells were collected using a 1 ml pipette and incubated on ice in whole cell lysis buffer ( cell signalling , beverly , ma , usa ) with 5 l / ml of protease inhibitor ( sigma ) lysis buffer for 5 mins and centrifuged for 20 mins at 13,000 rpm at 4c .
prior to sds - page , protein concentrations were determined using the biorad quantification assay measuring absorbance at 655 nm . approximately 15 g of extracted protein per sample was resolved by sds - page and subsequently transferred onto polyvinyl difluoride ( pvdf ) membranes ( ge healthcare ) 100 v constant at 4c . following transfer ,
the membrane was then blocked in 5% ( wt / vol ) milk in tris - buffered saline ( tbs ) supplemented with 0.1% tween 20 ( tbst ) for 1 h. the membrane was then probed with phospho - p65 ( ser 536 ) ( cell signalling ) primary antibody ( 1 : 1000 in tris - buffered saline ) overnight at 4c followed by the appropriate secondary antibody ( 1 : 2000 in 1% milk / tbs ) for 1
chemiluminescence detection was then carried out with ecl plus ( ge healthcare ) , and the membranes developed using a high - performance chemiluminescence film ( ge healthcare ) .
statistical analysis was performed with graph - pad prism ( v4.0 ; graphpad software , san diego , ca , usa ) . paired student 's t - test or repeated measures anova
was conducted where appropriate . samples with p < 0.05 was considered to be statistically significant .
a change in the production of the th1 and th2 cytokines in pregnancy has previously been described . in this study , we employed flow cytometry to examine the effect of stimulation by the mitogen pma / ionomycin on cytokine production at different gestational stages of pregnancy and during labour ( see figure 1 ) .
th1 cytokine profiles of cd4 positive cells were assessed for intracellular ifn- and tnf- ( figures 1(a)1(d ) ) and compared to levels of nonpregnant controls . the percentage of peripheral t cells producing ifn- in response to stimulation reduced in pregnancy from 10.7% in nonpregnant women to 6.7% at 28 weeks , 5.1% at term ( p < 0.05 ) , and 5.6% at term in labour ( p < 0.05 ) .
similarly , the proportion of tnf- producing cells was reduced , although not significantly , from 20.6% in nonpregnant women to 14.5% at 28 weeks , 15.8% at term and 13.3% at term in labour . overall levels of th1 cytokine production ( expressed as mean fluorescence intensity ) , in the cd4/ifn- or cd4/tnf- cells remained consistent throughout gestation and unchanged compared to nonpregnant controls .
the th2 cytokine , il-4 , was similarly assessed in crth2 positive cells ( figures 1(e ) and 1(f ) ) .
while pma / ionomycin stimulation did not increase the percentage of il-4 expressing cells , the mean fluorescence intensity of il-4 was significantly increased in samples collected from women at 28 weeks ( 39.3 , p < 0.01 ) and at term ( 39.4 , p < 0.05 ) compared to levels of nonpregnant controls ( 37.1 ) .
levels of il-4 in term labouring samples were consistent with nonlabouring samples ( 37.1 ) . the ratio of the ifn- : il-4 producing cells reduces during pregnancy , due to the suppression of the th1 rather than the promotion of the th2 cytokine production ( figure 1(g ) )
. to determine whether the th2 response in pregnancy is reflected by an increase in the percentage of crth2 positive cells , we used cd4 as a marker of t helper cells and calculated the percentage these cells that express crth2 ( figure 2(a ) ) .
the percentage of crth2 positive cells in the cd4 positive population was observed to increase in the second trimester of pregnancy from 2.24% in nonpregnant women to 3.12% at 28 weeks before reducing to 2.75% at term and 2.4% in term labour , although statistical significance was not reached ( figure 2(b ) ) .
there was no significant increase in the mean fluorescence intensity of crth2 in t helper cells between nonpregnant and pregnant subjects ( figure 2(c ) ) , although a slight increase in crth2 production was noted in term labouring samples ( p = 0.15 ) .
we therefore explored the effect of 15dpgj2 on the th1 cytokines , ifn- and tnf-. to do this , cells were preincubated with 32 m of 15dpgj2 or vehicle control prior to the addition of pma / ionomycin before intracellular cytokines were detected by flow cytometry ( figures 3(a ) and 3(b ) ) .
15dpgj2 reduced the production of pma / ionomycin stimulated ifn- production ( measured as mean fluorescence intensity ) in t helper cells from 101.9 to 53 ( p < 0.01 ) in nonpregnant controls , 115.7 to 52.4 ( p < 0.01 ) in 28 week samples and from 110 to 60.7 in term ( p < 0.01 ) samples .
there was a nonsignificant decrease observed in term labouring samples also ( 88.3 to 66.3 , figure 3(c ) ) . similarly , a significant decrease in pma / ionomycin - induced tnf- production following treatment with 15dpgj2 was detected in all pregnant samples assessed ( figure 3(d ) ) .
the percentage of t helper cells producing ifn- was also reduced from 10.7% to 5.13% in nonpregnant women ( p < 0.01 ) , 6.6% to 3.4% at 28 weeks ( p < 0.01 ) , 5.1% to 2.5% at term ( p < 0.05 ) , and 5.6% to 2.9% ( p < 0.01 ) .
a reduction in the percentage of t cells producing tnf- was also seen with 15dpgj2 from 20.6% to 16.7% in nonpregnant women , 14.5% to 9.0% at 28 weeks ( p < 0.05 ) , 15.8% to 12.9% at term ( p < 0.01 ) , and 13.2% to 8.93% at term in labour ( p = 0.05 ) ( data not shown ) .
considering its anti - inflammatory properties , it was hypothesized that 15dpgj2 would induce an increase in il-4 production via its action on the crth2 receptor .
contrary to what was anticipated , 15dpgj2 had no effect on the production of il-4 ( figure 3(e ) ) .
consistent with this , the percentage of crth2+/il-4 + lymphocytes remained constant following 15dpgj2 treatment except for samples collected at 28 weeks gestation ( 1.65% to 1.16% , p < 0.05 ; data not shown ) .
peripheral blood mononuclear cells were incubated with vehicle control or 32 m 15dpgj2 and stimulated with pma / ionomycin for 10 min before being extracted and assessed for levels of phosphorylated p65 , the transcriptionally active subunit of nf-b .
pma / ionomycin treatment stimulated nf-b phosphorylation in all samples and at all gestational time points ( figure 4 ) .
pretreatment of cells with 15dpgj2 significantly reduced levels of p - p65 in samples collected from women at 28-week gestation .
a clear trend of decreased p - p65 following 15dpgj2 was observed in the remaining samples yet they did not return to basal levels of p - p65 .
the immunological paradox of pregnancy relies on a careful balance of both immune tolerance and immune suppression .
work by medawar , and later wegmann and colleagues , has led to the proposal that this balance is determined by a functional immune suppression via a shift from a th1 response to a th2 bias during pregnancy [ 10 , 20 , 32 ] .
although not all human and murine studies support the importance or the simplification of the th1 : th2 paradigm [ 18 , 19 , 33 ] , further understanding of this hypothesis to aid the development of new therapeutic strategies is still required . in this study , we have explored the th1 cytokines ifn- and tnf- , and the th2 cytokine il-4 throughout pregnancy , and examined the potential of the cyclopentenone pg crth2 agonist , 15dpgj2 , to act as a therapeutic agent to modulate the th1 : th2 response .
consistent with the notion of suppressed th1 cytokine response throughout gestation [ 16 , 17 , 34 , 35 ] , our results revealed a reduction in the percentage of ifn- and tnf--secreting t helper cells during pregnancy in response to pma / ionomycin stimulation ( figures 1(a ) and 1(c ) ) .
however , mean production of ifn- and tnf- remained constant within the cd4/ifn- and cd4/tnf- cell populations ( figures 1(b ) and 1(d ) ) .
this indicates that while fewer cells maintain the capacity to initiate a th1 response to inflammatory stimuli with advancing gestation , a compensatory mechanism facilitates increased ifn- and tnf- production .
these results suggest that th1 response during gestation is likely to be regulated at both an individual cellular level as well as at the level of the cell population . as normal human labour
reflects a proinflammatory state , we anticipated that the percentage of ifn- and tnf- producing t helper cells would increase with the onset of labour .
this may be due to the proinflammatory state of labour being a localized response in the uterus and fetal membranes , rather than an extending to peripheral inflammation .
this would be consistent with the localised increase in the dna binding activity of nf-b in amnion cells postlabour compared to prelabour and in myometrium during labour compared to pre - labour as well as the reported increase in labour of ifn- in amnion , choriodecidua , and placenta , and tnf- in the amniotic fluid , myometrium , and cervix [ 39 , 40 ] rather than in the peripheral blood .
a number of studies have shown that mitogen stimulation can induce il-4 production in pbmcs of the second and third trimesters of pregnancy in vitro [ 16 , 35 , 41 ] .
intrinsic il-4 production by pbmcs also shows an increase in pregnancy compared with nonpregnant controls [ 17 , 42 ] .
we therefore hypothesized that pma / ionomycin stimulation of pmbcs would drive il-4 production during pregnancy , and that this phenomenon would subside at term concurrent with the activation of inflammatory pathways involved in normal labour pathways .
to examine any evidence of a shift towards the th2 profile in peripheral blood during pregnancy , pbmcs were gated for crth2 ( a marker for th2 cells ) and the level of il-4 assessed ( figures 1(e ) and 1(f ) ) .
the percentage of crth2/il-4 secreting cells , as well as mean production levels of il-4 remained consistent throughout pregnancy and advancing gestation ( figures 1(f ) and 1(e ) ) although a slight increase in the percentage of il-4 secreting cells was observed in both nonstimulated and stimulated 28-week samples .
between 0.46.5% of peripheral blood cd4 cells of nonpregnant women express crth2 and secrete il-4 , but not ifn- , in response to pma and ionomycin and are thus typical of th2 cells .
consistent with this , we found that between 24% of cd4 pmbcs express crth2 ( figure 2(a ) ) .
this percentage was maintained throughout gestation with a minor , statistically nonsignificant , increase observed at 28 weeks ( figure 2(b ) ) .
tsuda et al . have previously reported an increase in crth2 expression in cd4 cells between nonpregnant ( 2.08% ) and 7-week gestation ( 3.43% , p = 0.02 ) , but it is possible that this effect is diminished with advancing gestation .
mean levels of crth2 expressed in cd4 cells were also unchanged through gestation and labour ( figure 2(c ) ) . taken together with the fact that we were unable to detect any difference in il-4 secretion levels in these cells upon mitogen stimulation , our results collectively suggest that the th2 response in pmbcs is maximised during pregnancy and can not be further stimulated .
this would imply that any beneficial effects of therapeutic agents intended to push the th2 : th1 ratio towards th2 would need to do so through inhibition of th1 , rather than upregulation of th2 .
although the percentage of crth2 expressing cd4 cells is low in the peripheral blood , we are unable to rule out any modest yet biologically significant changes in il-4 production from these cells at a tissue - specific level . to further investigate the potential of th2 promotion versus th1 suppression
, we examined the response of pbmcs to 15dpgj2 , an endogenous product of prostaglandin d2 ( pgd2 ) ( and potential therapeutic agent ) that has been shown to promote th2 bias through il-4 production in t helper 2 cells in vitro via crth2 . pgd2 is readily converted to 15dpgj2 by a series of dehydration reactions in the presence of albumin and is found in the amniotic fluid , placenta , and urine .
15dpgj2 pretreatment significantly inhibited the pma - stimulated production of both th1 cytokines : ifn- and tnf- , in nonpregnant and all pregnant samples ( figures 3(a)3(d ) ) .
however , no effect on the production of the th2 cytokine , il-4 , could be detected in response to 15dpgj2 treatment .
this may be due to an overriding effect of a non - crth2-mediated mechanism such as the inhibition of other signalling proteins involved the transcriptional regulation of il-4 expression .
evidence for this has been previously reported in a pma / ionomycin - activated t - cell line , where 15dpgj2 inhibited il-4 production in a dose - dependent manner through the downregulation of nuclear factor of activated t - cells ( nf - at ) activation .
the anti - inflammatory properties of 15dpgj2 are thought to be at least partly via the inhibition of the transcription factor nf-b .
nf-b is known to play a key regulatory role in controlling the th1 immune response by modulating the expression of th1 cytokines .
nf-b activity in pbmcs during pregnancy is reduced compared to nonpregnant controls , and it has therefore been suggested that this is responsible for suppressed th1 response in pregnancy . to determine whether the observed inhibitory effects of 15dpgj2 on th1 cytokine production may be via nf-b , treated cells were extracted , and levels of the transcriptionally active nf-b subunit p - p65 were examined by immunoblotting .
our results indicate that 15dpgj2 significantly inhibits p - p65 in pma / ionomycin stimulated t helper at 28 weeks of gestation .
this data provides evidence that the th1 inhibitory properties of 15dpgj2 are likely regulated through nf-b .
15dpgj2 is a cyclopentenone pg which possesses an ,-unsaturated carbonyl group in the cyclopentenone ring .
this group can form michael adducts with i kappa b kinase ( ikk ) , and the p65 and p50 subunits leading to modification of these proteins , thus inhibition of nf-b activity .
we have shown that in amnion and myometrial cells , inhibition of nf-b by 15dpgj2 is not via ppar- . however , 15dpgj2-mediated suppression of th1 interleukin expression in lymphocytes via ppar- receptor inhibition or activator protein 1 ( ap-1 ) has not been ruled out in this study . while 15dpgj2 appears to have no effect on the peripheral th2 response , the demonstrated inhibition of the th1 response represents a collective shift toward a th2 bias , or in other words , an increase in the th2:th1 ratio .
this has important ramifications for the future design of therapeutic strategies to prevent preterm labour and pregnancy loss ( figure 5 ) .
the percentage of crth2 positive decidual lymphocytes is far higher , accounting for 10.5% of t lymphocytes and 18% of cd4 + lymphocytes .
exploring the effect of 15dpgj2 on purified decidual t cells may give rise both th1 suppression and th2 cytokine promotion .
immunomodulating therapies such as progesterone ( for women at high risk of preterm labour ) and intravenous immunoglobulins ( for women with recurrent miscarriage ) are currently being used in a clinical context .
progesterone suppresses ifn- production in peripheral blood mononuclear blood cells cultured with trophoblasts and dydrogesterone suppresses both ifn- and tnf- whilst increasing il-4 in phytohaemagglutinin ( pha ) stimulated pbmcs leading to a substantial th1 to th2 shift .
immunoglobulins are capable of altering the th1 : th2 balance leading to a reduction in the cd4ifn-/cd4il-4 lymphocyte ratio . the endogenous protein , progesterone - induced blocking factor ( pibf ) , is capable of increasing the production of il-4 and il-10 in pbmc , but has no effect on the th1 cytokines ifn- and tnf- .
15dpgj2 may show more promising immunomodulating effects for the prevention of preterm labour exploiting its ability to both suppress the th1 cytokines with the added benefit of inhibiting nf-b activity .
preterm labour , particularly in the presence of chorioamnionitis , is associated with a shift towards the th1 cytokine response .
pbmcs of women in preterm labour when stimulated with pma produce significantly higher ifn- compared to women who go on to deliver at term .
the presence of ifn- in cervicovaginal fluid in the late second and early third trimesters has also been shown to be a risk factor for preterm labour in asymptomatic women . similarly , tnf- is thought to be key cytokine involved in the initial trigger of biochemical events leading to infection - mediated preterm birth , for example , by causing prostaglandin e2 ( pge2 ) synthesis by intrauterine tissues which drive pathways leading to uterine contractility and cervical ripening [ 6163 ] .
while global changes in the pbmcs likely reflect important systemic inflammatory events , their sub - components ( e.g. , t cells , b cells , and monocytes ) may play functionally independent roles at the maternal fetal interface .
future work using an in vivo model examining effects of 15dpgj2 and crth2 agonists on th1 and th2 interleukins at local sites ( e.g. , decidua and myometrium ) would allow us to extrapolate how immune cells influence nonimmune cell function .
prophylactic administration of 15dpgj2 to women at high risk of preterm birth may lead to the inability of infection to activate nf-b and thus preventing transcription of labour associated genes , and the inability to alter the th1 : th2 bias to favour th1 , thus preventing the pro inflammatory detrimental environment of the fetus .
consideration for the route of administration should be supported by further studies of the potential local effect of 15dpgj2 on interleukin production from the cervix , myometrium , and fetal membranes . the anti - inflammatory effect on nf-b and the th1 interleukins
may not be replicated in the cervix , for example , which would serve as the least invasive route of administration of 15dpgj2 in the form of a pessary .
absorption at the local level is also unlikely to provide systemic levels high enough to effect peripheral cytokine production , likewise , the effect of peripheral administration on the local maternal fetal interface is not guaranteed to result in a physiological effect .
nevertheless , this study shows promising potential for the future application of 15dpgj2 as an immunomodulating therapy for infection - mediated preterm labour , and thus further studies examining its effect on gestational tissues should be pursued .
this study presents evidence that the th1 : th2 balance is changed in pregnancy through th1 suppression rather than th2 promotion .
we have also demonstrated the potential anti - inflammatory effects of 15dpgj2 through the suppression of nf-b and the th1 proinflammatory cytokines ifn- and tnf-. these properties may be of therapeutic benefit for the prevention of infection - mediated preterm labour and the reduction of inflammation induced neonatal morbidity , where an aberrant profile favouring the th1 response is seen .
thus , future work in this area may be best directed toward designing therapeutic strategies aimed to manipulate the th1 response during pregnancy as a rational strategy for the prevention of preterm labour and pregnancy loss / miscarriage . | ### Summary:
: pregnancy is a complex immunological state in which a bias towards t helper 2 ( th2 ) protects the fetus .
evidence suggests that proinflammatory cytokines increase the risk of poor neonatal outcome , independently of the direct effect of preterm labour . the anti - inflammatory prostaglandin 15-deoxy-12,14-prostaglandin j2 ( 15dpgj2 ) inhibits nuclear factor kappa b ( nf-b ) in amniocytes and myocytes in vitro and is a ligand for the chemoattractant receptor - homologous molecule expressed on th2 cells ( crth2 ) receptor .
here we examine the th1:th2 cytokine bias in pregnancy and whether 15dpgj2 could be used to inhibit the production of the proinflammatory cytokines through inhibition of nf-b while simultaneously promoting th2 interleukin 4 ( il-4 ) synthesis via crth2 in t helper cells . peripheral blood mononuclear cells ( pbmcs ) from women at 28 weeks , term pre - labour , term labour as well as non - pregnant female controls were cultured with 15dpgj2 or vehicle control and stimulated with phorbol myristyl acetate ( pma)/ionomycin .
the percentage of cd4 + cells producing interferon gamma ( ifn- ) and tumor necrosis factor alpha ( tnf- ) in response to pma / ionomycin was significantly reduced in pregnancy .
15dpgj2 reduced ifn- and tnf- production in stimulated t helper cells , but did not alter il-4 production in crth2+ve cells .
15dpgj2 also reduced phospho - p65 in stimulated pbmcs . in summary
, 15dpgj2 suppresses the th1 response of pbmcs during pregnancy and active labour whilst maintaining the th2 response suggesting a therapeutic benefit in reducing neonatal morbidity in inflammation - induced ptl . |
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: a macular hole ( mh ) is a full - thickness neuroretinal defect or break of the fovea , most of which are considered idiopathic .
mh is sight - threatening and not uncommon ; however , not until 1991 did kelly and wendel reported it to be treatable via internal limiting membrane ( ilm ) peeling assisted pars plana vitrectomy ( ppv ) , which was later established to be a standard surgical technique for this condition .
the second milestone of mh surgery was laid by kadonosono et al . in 2000 when indocyanine green ( icg ) was applied during surgery for staining of ilm before peeling , thus providing a way to better visualize , easier , and more completely remove the ilm .
other dyes , such as trypan blue and brilliant blue g , were later introduced as alternatives for ilm staining . despite the above - mentioned advances in surgical techniques , however , quite a proportion of the mhs did not achieve complete closure but were so - called flat - open with bare retinal pigment epithelium and absence of foveal neurosensory retina , especially in cases with large mh ( minimum diameter > 400 m ) or high myopia . although considered anatomically successful , flat - open closure of mh usually resulted in limited postoperative functional recovery . a continuing effort of refinements on vitreoretinal surgery led to another innovative technique established by michalewska et al . in 2010 ,
technique , which was proved to be able to increase the rate of complete closure as well as the final visual outcome .
this technique was later used in patients with massive mh ( minimum diameter > 700 m ) or high myopia with satisfactory results except for high myopic patients complicated with retinal detachment . however , to the best of our knowledge , best corrected visual acuity ( bcva ) was the only functional index used in the limited number of published studies applying the inverted ilm flap technique . in this study ,
multifocal electroretinogram ( mferg ) , which allows detailed topographical mapping of the retinal function in the central macula , was documented and compared before and after surgery in patients with large mhs ( > 400 m ) who underwent inverted ilm flap technique assisted ppv , trying to combine the mferg results to the microstructural changes detected by spectral - domain optical coherence tomography ( sd - oct ) .
it complied with the tenets of the declaration of helsinki ( as revised in brazil 2013 ) and was approved by ethics committee of our hospital .
patients who presented to our group with large ( minimum diameter > 400 m ) idiopathic stage iii - iv ( gass classification ) mhs from june to december 2014 were included .
exclusion criteria included : high myopia ( > 6 diopters ) , increased intraocular pressure ( iop , > 21 mmhg ) or glaucoma , moderate to severe cataract , severe systemic conditions that prevent surgery , and history of ocular trauma , intraocular inflammation , retinal vascular disease , or previous ocular surgery .
each patient received a complete ophthalmological examination and the following clinical parameters were obtained at baseline and 2 weeks , 13 months and ad - lib postoperatively : bcva ( recorded in decimals and was converted to logarithm of the minimum angle of resolution units for statistical analysis ) , iop ( auto - tonometer tx-20 , canon , tokyo , japan ) , minimum and base mh diameter on sd - oct ( 3d - oct 1000 , topcon , tokyo , japan ) .
mferg ( veris - edi system , califronia , usa ) was not conducted until 1 month after surgery for the sake of avoiding infection and was monitored during the following visits . the erg protocol complied with the standards published by the international society for clinical electrophysiology of vision .
one - hundred and three hexagonal stimulus elements that scaled concentrically and covered the central 50 of the fundus were applied to each patient when examine mferg .
the central hexagon ( representing foveal area ) corresponded to approximately 2.8 , and the central seven hexagons ( representing macula , including foveal and perifoveal areas ) to approximately 5. three - dimensional plots and retinal response density ( [ rd ] , defined as amplitude per retinal area , nv / deg ) value plots were used to demonstrate the topographical retinal electrical activities .
a standard 3-port ppv ( 23-gauge ) ( stellaris , bausch and lomb , new york , usa ) with inverted ilm flap technique was performed in all patients by a single experienced surgeon . after a core vitrectomy
, posterior vitreous detachment was created , followed by removal of the residual premacular posterior vitreous cortex .
then , icg ( 0.125% solution ) was slowly injected toward the ilm around the mh instead of directly toward it to minimize retinal toxicity , and let the ilm be stained for about 30 s. after that , the ilm along with any epiretinal membrane if present was grasped and peeled off in a circumferential pattern for about 11.5 disk diameter around the mh using ilm forceps , leaving only the innermost narrow circle of ilm attached to the macular border by a pedicel .
then , this remnant of ilm was gently turned upside - down toward the bottom of the mh and was carefully flattened to make sure it was properly positioned rather than packed irregularly .
the perfusion pressure was set at the lowest level ( 30 cmh2o ) that the vitrectomy machine allowed when covering the mh with the inverted ilm flap and during the air - fluid exchange to avoid the flimsy flap being washed away . at the end of surgery
, 14% c3f8 gas tamponade was applied to secure the position of the inverted ilm flap and the postoperative face - down position was instructed for at least 1 week .
bcvas and rd of the central hexagon and the central seven hexagons on mferg at different time points ( baseline , 1 and 3 months after surgery ) were compared pairwisely by post - hoc tests after analysis of variance .
pearson tests were conducted to evaluate the correlation between bcvas and mferg responses at each measurement point . a value of p < 0.01 was considered to be statistically significant .
bcvas and rd of the central hexagon and the central seven hexagons on mferg at different time points ( baseline , 1 and 3 months after surgery ) were compared pairwisely by post - hoc tests after analysis of variance .
pearson tests were conducted to evaluate the correlation between bcvas and mferg responses at each measurement point . a value of p < 0.01 was considered to be statistically significant .
a total of eight eyes in eight consecutive patients ( four men and four women ) were enrolled .
the postoperative follow - up period ranged from 3 to 10 months ( mean 6.0 2.7 months ) .
basic demographic data , related biometric measurements , visual acuity and mferg response of patients with large macular holes mh : macular hole ; bcva : best corrected visual acuity ; logmar : logarithm of the minimum angle of resolution ; rd : response density ; mferg : multifocal electroretinography ; min : minimal ; max : maximal or basal ; fovea and macula represents the most central and the central 7 hexagonal areas on mferg , respectively .
all patients underwent successful ilm peeling , intended manipulation , and translocation of the ilm flap .
complete closure ( defined as no neurosensory defect at the fovea on sd - oct ) was observed in all eyes 2 weeks after surgery ( although the tissue filling the original mh appeared more likely to be sheets of inverted ilm flap ) , followed by a gradual microstructural reconstruction afterward marked by partial restoration of the back - reflection lines representing the external limiting membrane ( elm ) and ellipsoid zone ( ez ) on sd - oct [ figure 1 ] .
encouragingly and in consistency with the reconstruction process of the foveal microstructure , all patients except one ( 7/8 ) showed incremental improvements of visual function ( both in bcva and mferg responses ) over time during the first 3 months after surgery [ figure 2 ] . the exceptional patient , however , demonstrated depressed mferg responses at 1 month after surgery with limited recovery detected at 3 months , although a contemporary slow increase in bcva was observed [ figure 3 ] .
interestingly , in accordance with the mferg changes , the central defects of the elm and the ez appeared widened at the 1-month postoperative visit as compared to baseline , followed by partial restoration observed at 3 months after surgery ; in addition , the temporal inner macular surface appeared rugged after surgery , suggesting the possibility of nerve fiber layer injury during ilm peeling [ figure 3 ] .
spectral - domain optical coherence tomography images of the microstructural reconstruction process of a large macular hole in a 66-year - old female patient .
( a ) the preoperative minimum and base diameter of the macular hole was 905 m and 1213 m , respectively .
note the cystoid edema of the elevated margin and the disrupted external limiting membrane / ellipsoid zone ( between the two arrows ) .
( b ) closure of the macular hole was observed 2 weeks after surgery , although the tissue filling the macular hole appeared to be sheets of inverted internal limiting membrane ( flap closure , arrowheads ) .
( c ) one month after surgery , the inner layers of the neurosensory retina thickened along the internal limiting membrane scaffold , leaving only a small defect of the outer retina ( asterisk ) .
the leading edge of the reconstructing external limiting membrane ( arrowheads ) and the ellipsoid zone ( arrows ) were both growing towards the center of the macular hole compared with the original sites before surgery .
( d ) three months after surgery , the macular contour appeared further normalized , and the neurosensory retinal tissue above the fovea further thickened , leaving only a cleft ( asterisk ) .
although not fully recovered at this stage , the external limiting membrane and the ellipsoid zone appeared more regular and clear .
representative spectral - domain optical coherence tomography and multi - focal electroretinogram changes of a 53-year - old female patient preoperative minimum and base diameters were 734 m and 965 m , respectively ; defects of the external limiting membrane and the ellipsoid zone were indicated by arrow heads and arrows , respectively .
cystoid edema and elevation of the margin were demonstrated ( a ) . on three - dimensional plot of multi - focal electroretinogram ,
the foveal and perifoveal area showed two separate small peaks ( d ) , which reflected marked depression of the macular area and poor fixation due to low central vision .
the response density of the central seven hexagons in this patient ( g , the black numbers within the red hexagon ) were much lower than a normal subject ( g , the blue numbers ) .
one month after surgery , the macular hole closed , with partial restoration of both the external limiting membrane and the ellipsoid zone ( b ) .
the corresponding multi - focal electroretinogram showed a confluent blunt single peak ( e ) , and the average retinal response density of the central seven hexagons and the fovea had increased from preoperative 8.5 and 8.8 nv / deg to 9.5 and 12.3 nv / deg , respectively ( h ) .
three months postoperatively , a further inward reconstruction of the external limiting membrane and the ellipsoid zone were observed ( c ) . on three - dimensional plot of multi - focal electroretinogram , the peak became more sharp , with higher elevated immediate surrounding area ( f ) ; the corresponding average retinal response density of the central seven hexagons and the fovea had increased to 11.1 and 12.5 nv / deg , respectively ( i ) .
representative spectral - domain optical coherence tomography and multi - focal electroretinogram changes in a 67-year - old female patient preoperative minimum and base diameters were 478 m and 854 m , respectively ; defects of the external limiting membrane were indicated by arrow heads and the ellipsoid zone by arrows .
n and t represent nasal and temporal side of the macula , respectively .
at baseline , on spectral - domain optical coherence tomography , cystoid edema was more prominent on the temporal side of the macular hole ( a ) , and there was a single small peak on three - dimensional plot of multi - focal electroretinogram ( d ) and the average retinal response density of the central seven hexagons and the fovea ( g , the black numbers within the red hexagon ) were 8.4 and 10.1 nv / deg , respectively ; the initial best corrected visual acuity was 0.02 ( 20/1000 ) .
one - month postoperatively , the macular hole had closed , but the defects of the external limiting membrane and the ellipsoid zone were larger than baseline levels , especially on the temporal side ; note also the rugged inner surface of the temporal macula ( asterisk ) ( b ) ; the central peak on the three - dimensional plot of multi - focal electroretinogram was further depressed , ( e ) with average retinal response density of the central seven hexagons and the fovea decreased to 5.0 and 6.0 nv / deg , respectively ( h ) ; however , the best - corrected visual acuity still increased to 0.05 ( 20/400 ) .
three months after surgery , defects of the external limiting membrane and the ellipsoid zone were partially restored although the inner surface of the temporal macula became even more rugged ( asterisk ) ( c ) ; a mild recovery of the central peak on the three - dimensional plot of multi - focal electroretinogram was detected ( f ) with average retinal response density of the central seven hexagons and the fovea increased to 5.8 and 7.5 nv / deg , respectively ( i ) ; the best corrected visual acuity increased to 0.10 ( 20/200 ) . from a statistical point of view
, significant improvements in bcva were observed as early as 1 month after surgery [ figure 4a ] , while for rd of central seven hexagons and the fovea , not until 3 months after surgery did their increase reach significance [ figure 4b ] .
bcva neither significantly correlated with mferg rd of fovea nor with rd of the central seven hexagons at each evaluation time point [ figure 5 ] , despite their similar incremental tendency after surgery [ figure 4 ] .
longitudinal evaluations of best corrected visual acuity and multi - focal electroretinogram responses . as shown in figure , increasing trends in best corrected visual acuity ( a ) and multi - focal electroretinogram responses ( b ) were observed during the first 3 months after srugery .
one - way analysis of variance and tukey 's multiple post - hoc comparison tests were used for analysis for visual acuity ( a ) , and two - way analysis of variance with bonferroni post - hoc tests were used for comparions between multi - focal electroretinogram responses at different time points ( b ) .
results of statistical analysis were indicated ( p < 0.01 and p < 0.001 were defined as significant [ * ] and very significant [ ] , respectively ; [ ] means not significant ) .
bcva : best corrected visual acuity , logmar : logarithm of the minimum angle of resolution .
pre - op : preoperative ; 1 m post - op : postoperative 1 month ; 3 m post - op : postoperative 3 months .
associations between best corrected visual acuity in logarithm of the minimum angle of resolution and response densities of fovea or central 7 hexagons at base line ( pre - op ) , 1 month after surgery ( 1 m post - op ) and 3 months after surgery ( 3 m post - op ) .
although improvement could be observed with time for both paremeters , there was no clear correlation between best corrected visual acuity and multi - focal electroretinogram responses at each evaluation time point , and retinal response densities varied in patients even with the same best corrected visual acuity ( p < 0.01 was defined as significant ) .
bcva : best corrected visual acuity , rd : response density , logmar : logarithm of the minimum angle of resolution .
two eyes had a transient elevation of iop and were well controlled by topical antiglaucoma medications .
none of the included eyes developed severe cataract and any other complications that might compromise visual function , interfere with the examinations or necessitate surgery during follow - up .
the closure rate of mhs was 68% when ilm peeling assisted ppv was first introduced to manage idiopathic mh , and have recently improved to 86100% with the aid of ilm staining technique .
large mhs ( minimum diameter > 400 m ) , however , usually had an increased risk of surgical failure , and the closure rate of mhs with high myopia , reported between 83% and 87% , appeared to be lower than the idiopathic forms .
in addition , about 1939% of the so - called anatomically closed large mhs were actually flat - open .
this is not hard to understand considering that the traditional ilm peeling might only release the tangential traction , but can not compensate for tissue shortening in large mhs .
encouragingly , the recent advent of the inverted ilm flap technique had increased the rate of complete closure to 98% in the original study for large idiopathic mhs , and to 100% in a report for high myopic mhs . in this study , with all mhs achieved complete closure , further supported the reliability of this technique for the management of large mhs .
the inverted ilm flap technique , however , is not without limitations . in the original report , spontaneous detachment of the flap occurred in seven of fifty eyes during the air - fluid exchange . to address this , shin et al .
described a modified technique in which perfluoro - n - octane was used to assist the covering of the mh with a single sheet of ilm flap . in our experience , we found that lowering the perfusion pressure when inverting the flap and during air - fluid exchange might help to avoid the flap from being washed away , and indeed no dislocation of the ilm flap occurred during surgery in the current study .
another notable modification of this technique reported recently by the original authors was to peel only the temporal side of the ilm instead of the whole area around the fovea , which was found to be associated with a reduction in the frequency of having a dissociated optic nerve fiber layer appearance .
the proposed mechanisms for tissue repair in the mhs following inverted ilm flap technique assisted ppv were as follows : the inverted ilm which contained mller cell fragments not only provoked gliosis via activating tissue necrosis growth factor- but also served as a scaffold and basement membrane for tissue proliferation , thus providing an environment to instruct the photoreceptors to assume correct position during the reconstruction process and finally to improve the postoperative vision . the microstructural recovery process of the mhs after surgery revealed by sd - oct in our study was in line with the above - mentioned speculation [ figure 1 ] : a membranous structure ( which we believe was the inverted ilm ) bridging over the macula defect
was observed 2 weeks after surgery and seemed to serve as a scaffold for the repairing tissue because the subsequent repair appeared to proceed in an inner - to - outer manner .
in addition , based on the observations in our study and as proposed previously , restoration of the elm might be important for visual recovery as the leading edge of the reconstructing elm was found to precede that of the ez in all patients in our study .
unintended injury of the nerve fiber layer during ilm peeling , however , might compromise recovery of bcva and mferg [ figure 3 ] .
although both bcva and mferg responses improved incrementally after surgery [ figure 4 ] , they were not found to be statistically correlated at each evaluation time point of our short - term observation [ figure 5 ] as well as in previous longer term studies concerning conventional surgical technique ( just ilm peeling but without inverting ) in treatment of mhs .
the lack of correlation between bcva and mferg responses suggested that these two functional evaluation modalities could not adequately represent , but might be supplemental to , each other in the clinical setting of mhs , and might be explained by the following differences between them : bcva is a subjective measurement and only measure the function of the fixation point under optimal condition , while mferg is an objective measurement and provides a topographic electrophysiological mapping of the central retina .
further studies combining bcva , oct , mferg , and subjective functional mapping of the central retina , such as microperimetry , might provide a more comprehensive evaluation of the patients with mhs .
this study is a prospective study in large idiopathic mhs treated with inverted ilm flap assisted ppv that combined the microstructural recovery process with changes of two aspects of functional evaluations ( bcva and mferg response ) and analyzed the association between bcva and mferg .
the following major limitations of this study should be kept in mind when interpreting the results : ( 1 ) the absence of a control group , ( 2 ) the limited sample size , and ( 3 ) the limited length of follow - up .
however , we would like to point out that , no control group was designed considering the rareness of large macular holes ( minimum diameter > 400 m ) , and no other effective treating methods had been verified and reported in the literature by far .
further studies with more cases and longer term observations could be conducted , although it still would be very time consuming . in conclusion
, inverted ilm flap technique appeared to be a safe and successful approach for the management of large idiopathic mhs with promising short - term anatomical and functional results .
lowering perfusion pressure when inverting the ilm flap and during air - fluid exchange might help to avoid dislocation of the ilm flap during surgery .
postoperative reconstruction of the foveal microstructure generally showed good consistency with improvements in both bcva and mferg response .
and although not significantly correlated , mferg response might be a good supplement for bcva to evaluate postoperative functional recovery .
| ### Summary:
: background : inverted internal limiting membrane ( ilm ) flap technique has recently been reported in a limited number of studies as an effective surgical technique for the management of large macular holes ( mhs ) with fair mh closure rates as well as gains in visual acuity . in the current study , longitudinal changes in multi - focal electroretinogram ( mferg ) responses ,
best - corrected visual acuity ( bcva ) and spectral - domain optical coherence tomography ( sd - oct ) were evaluated in eyes with large mhs managed by this technique.methods:a prospective noncontrolled interventional study of eight patients ( eight eyes ) with large mhs ( minimum diameter > 400 m ) was conducted .
all mhs were treated with pars plana vitrectomy and indocyanine green - assisted inverted ilm flap technique .
sd - oct images were used to assess the anatomical outcomes of surgery while bcva and mferg were used to evaluate the functional outcomes during a 3-month follow-up.results:all patients underwent successful intended manipulation and translocation of the ilm flap without flap dislocation and achieved complete anatomical closure .
partial microstructural reconstruction , demonstrated on sd - oct as restoration of the external limiting membrane and the ellipsoid zone , was observed in all cases as early as 1 month after surgery .
functionally , as compared to baseline , all patients showed improvements in bcva and all but one in mferg response during follow - up .
however , pearson 's test revealed no significant correlations between bcva and mferg responses of the fovea and of the macular area at each evaluation time point.conclusions:inverted ilm flap technique appeares to be a safe and effective approach for the management of large idiopathic mhs with favorable short - term anatomical and functional results .
postoperative reconstruction of the microstructure generally shows good consistency with improvements in both bcva and mferg response , of which the latter might be a supplement for the former in postoperative functional follow - up . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: soma ( carisoprodol ) is a commonly prescribed , centrally acting skeletal muscle relaxant that inhibits interneuronal transmission in the descending reticular formation and spinal cord .
a few case reports have now been reported in the literature suggesting the addiction potential of carisoprodol .
a 57-year - old chronic alcoholic , diabetic , hypertensive , hypothyroid male was admitted to a tertiary hospital for bilateral knee replacement .
his daily medications included losartan ( 50 mg ) , metformin ( 1 g ) and eltroxin ( 0.75 mg ) for the last 2 years .
gradually , he also developed visual hallucinations , restlessness , insomnia , and profuse sweating . with the possibility of metabolic disturbance
was given in escalating doses ( 15 mg / day ) . in spite of treatment with haloperidol and
zolpidem his condition worsened and was shifted to the critical care unit for assessment of need of mechanical ventilation . in the intensive care unit ( icu ) ,
his pulse rate was 112/min , blood pressure of 128/74 mmhg , respiratory rate of 30/min , temperature 101f and spo294% on oxygen supplementation .
his general condition kept on deteriorating with increasing tachypnoea up to 40/min , tachycardia ( 130/min ) , and worsening delirium ( detected using the confusion assessment method - cam score ) .
laboratory investigations showed an elevated white blood cell count ( 19,000/mm ) , creatinine phosphokinase -11560 units / dl , ( mb isoenzyme 45 units / dl ) , serum glutamic oxaloacetic transaminase -238 units / dl , serum glutamic pyruvic transaminase -154 units / dl and lactate dehydrogenase-124 units / dl , blood urea-45 mg / dl .
urine analysis , serum electrolytes , chest roentgenogram , electrocardiography , computed tomography head , drug screen , blood cultures , lumbar puncture , and thyroid profile were all unremarkable .
the other differential diagnoses considered in the icu were an infectious pathology , pulmonary embolism , alcohol withdrawal or nms .
the whole case was re - evaluated , and it was revealed that the patient was consuming soma to alleviate his knee pain . over time , he became dependent and consumed double the indicated dose ( 6 - 7 tablets ) daily since last 10 years . due to the presence of a generalized rigidity , high - grade fever , fluctuations in sensorium , autonomic dysfunction , distal myoclonus , and marked elevated creatine phosphokinase ( cpk ) possibility of possible nms was considered and he was started on baclofen ( 30 mg / day ) and lorazepam ( 6 mg / day ) . over the next 48 h , he was calm and oriented though sedated . in the next two days , myoclonus and rigidity disappeared ,
cpk levels dramatically declined ( 189 mg / dl ) , and his condition completely stabilized .
soma ( carisoprodol ) is n - isopropyl-2 methyl-2-propyl-1,3-propanediol dicarbamate ; and is routinely used in primary care settings for the treatment of musculo - skeletal disorders associated with muscle spasms and back pain .
it exerts its effect through central sedation and has an indirect agonist effect on the gamma - aminobutyric acid - a receptors .
it is accepted that therapeutic effects of carisoprodol and its abuse potential are due to its conversion to meprobamate .
half - life of carisoprodol and pharmacologically active metabolite , meprobamate is 2 - 3 h and 11 h , respectively , but may increase to 48 h with chronic use . to the best of our knowledge , there are only five case reports reported till date .
withdrawal symptoms have occurred when intake of 700 - 2100 mg / day of carisoprodol was suddenly stopped after 9 months .
propose that carisoprodol withdrawal may have precipitated nms when daily intake of large doses was abruptly stopped in this case .
this diagnosis was supported by clinical features and laboratory parameters with complete resolution of the syndrome after institution of treatment and normalization of laboratory parameters .
long - term consumption of heavy doses induces neural adaptation to their presence and rebound resurgence of neural electrical activity occurs after its sudden withdrawal .
the rebound leads to symptoms ranging from anxiety , jitteriness to delirium , depending on the severity of withdrawal and degree of neuronal hyperactivity .
the typical meprobamate withdrawal syndrome may involve various degrees of insomnia , vomiting , tremors , muscle twitching , overt anxiety , anorexia , ataxia , and bizarre behavior .
he had insomnia , delirium , hallucinations , and cold sweating after 48 h of drug cessation with associated features like fever , rigidity , myoclonus , and high cpk levels . in our patient ,
as he developed respiratory distress , pulmonary embolism in the setting of postoperative period was a differential .
when he developed fever , muscular rigidity , leukocytosis , altered consciousness , and elevated ck levels diagnosis of nms was considered .
our patient had possible nms as there were clinical features to suggest the syndrome and normalization of the laboratory parameters after start of specific treatment . however , in our patient , it was the cessation of soma abuse which led to nms as the symptoms appeared prior to administration of haloperidol . as dantrolene was not readily available baclofen
it resolved the rigidity in few hours with improvement in sensorium , general condition , and ck levels .
our patient was addicted to soma , and sudden withdrawal may have precipitated nms in the postoperative period which was successfully managed with supportive therapy and specific treatment with baclofen and benzodiazepine .
thus , clinicians should exercise high degree of suspicion in managing postoperative psychosis and nms . | ### Summary:
: soma ( carisoprodol ) is n - isopropyl-2 methyl-2-propyl-1,3-propanediol dicarbamate ; a commonly prescribed , centrally acting skeletal muscle relaxant .
neuroleptic malignant syndrome ( nms ) is a potentially life - threatening adverse effect of antipsychotic agents .
although diagnostic criteria for nms have been established , it should be recognized that atypical presentations occur and more flexible diagnostic criteria than currently mandated , may be warranted .
we wish to report a postoperative case of bilateral knee replacement who presented with carisoprodol ( soma ) withdrawal resembling nms that was a diagnostic dilemma .
subsequently , it was successfully treated with oral baclofen in absence of sodium dantrolene . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: cancer is the second leading cause of mortality in the united states after heart disease.1 over the years , cancer survival has significantly improved due to a better understanding of cancer biology and the availability of various forms of treatment .
one of the core modalities in cancer treatment is chemotherapy . a dreaded side effect , however , is chemotherapy - induced nausea and vomiting ( cinv ) .
treatment for cinv has evolved over the past 2 decades and includes supportive and pharmacologic treatment .
controlling cinv improves the patient s functional status , quality of life , and capacity to perform activities of daily living.2,3 nonpharmacologic management of cinv that has been described includes yoga , music therapy , acupressure , concord grape , and ginger .
a systematic review of these interventions has been done and showed insufficient evidence that the said interventions benefit patients with cinv .
non - pharmacologic interventions could be an adjunct given the low risk for toxicities.4 an important aspect in the management of cinv is patient education regarding the timing , prevention , and treatment of cinv.5 several medications address the problem of acute and delayed cinv .
the medications that are recommended vary with the emetogenic risk of a chemotherapeutic regimen . for highly emetogenic chemotherapy , a combination of a serotonin antagonist 5-hydroxytriptamine 3 ( 5-ht3 ) , dexamethasone , and neurokinin inhibitor has been recommended .
palonosetron combined with dexamethasone is preferentially used for moderately emetogenic regimens . for low - risk patients ,
prechemotherapy dexamethasone is offered.3,6 the introduction of neurokinin inhibitors has greatly improved the ability to prevent and treat persistent cinv in patients receiving moderate to highly emetogenic chemotherapy .
this review will focus on the use of the neurokinin inhibitor , fosaprepitant , in the management of cinv .
cinv is brought about by a complex process involving interconnected neurological pathways , neurotransmitters , and receptors.7 emetogenic receptors are concentrated in three locations in the brainstem : the vomiting center in the medulla oblongata , the chemoreceptor trigger zone in the area postrema in the floor of the fourth ventricle , and the nucleus of the solitary tract .
these areas are rich in 5-ht3 , neurokinin-1 ( nk-1 ) , and dopamine ( d ) receptors .
serotonin , substance p , and dopamine bind to these receptors , respectively , to initiate the sensation of nausea and the vomiting reflex.8 the gastrointestinal tract is composed of mechanical and chemical receptors .
alterations in the chemical balance of different substances detected by chemoreceptors lead to the activation of vagal afferents , which leads to a cascade of events that then lead to nausea and vomiting.9,10 most emetogenic antineoplastic drugs are toxic to the enterochromaffin cells lining the gastrointestinal tract that store and release serotonin .
exposure to these agents leads to the release of serotonin that binds to 5-ht3 receptors in the gut , thereby activating the vagal afferents in the gut and brainstem.11,12 the nk-1 receptor is the main receptor for the tachykinin family of peptides that includes substance p. substance p has also been implicated in the pathogenesis of cinv.13 substance p and nk-1 receptor are found in relevant sites ( vagal afferent , nucleus tractus solitarius , and gastrointestinal mucosa ) that are essential in the process of emesis .
binding of substance p to nk-1 receptors initiates a cascade of events causing nausea and vomiting .
various stimuli that activate this pathway include chemotherapeutic agents such as cisplatin , radiation , opioids , apomorphine , and electrical stimulation of abdominal vagal afferents .
the anatomical localization of these sites has led to the development of antagonists against nk-1 receptor in the treatment of cinv.14,9
this greatly affects the quality of life of cancer patients.15 risk factors identified for the development of cinv include female sex , alcohol use , and younger age.1618 these risk factors also predict the failure of antiemetics for both prophylaxis and treatment of cinv ( table 1 ) .
the emetogenic potential is defined depending on the level of risk : minimal risk ( < 10% ) , low risk ( 10%30% ) , moderate risk ( 30%90% ) , and high risk ( > 90% ) ( table 2 ) .
cinv is classified based on the timing of occurrence : it may be acute if it occurs within initiation of chemotherapy ( lasts < 24 hours ) , delayed if it occurs after 24 hours ( persisting for 67 days ) , or anticipatory ( prior to chemotherapy administration).19
kenilworth , nj , usa ; ivemend merck sharp & dohme ltd , hertfordshire , europe ) is an nk-1 receptor antagonist that is approved for the treatment of cinv .
the prodrug , fosaprepitant , is converted into the active aprepitant to exert its antiemetic properties.20 it is converted into the active drug , aprepitant , in hepatic and extrahepatic tissues ( kidney , lungs , and ileum ) .
brain barrier and block the nk-1 receptor that is widely distributed in the central nervous system .
fosaprepitant has a half - life of approximately 2.3 minutes , with plasma levels below the level of detection in 30 minutes . in the plasma ,
the volume of distribution of both aprepitant and fosaprepitant is 70 l. given the high volume of distribution , the drug stays in the body for a longer period of time , hence its efficacy for delayed cinv.21 aprepitant is metabolized mainly by the cyp3a4 , with minor metabolism via the cyp1a2 and cyp2c19 .
in contrast , fosaprepitant is a weak inhibitor when administered as a single 150 mg intravenous infusion .
this becomes important for patients who take drugs that are likewise metabolized through this process because coadministration will need dose adjustments ( table 3).21,22
aprepitant is one of the first nk-1 receptor antagonists approved for the prevention and management of nausea and vomiting brought about by moderately and highly emetogenic chemotherapy .
it is conventionally administered orally for 3 days ( 125 mg on day 1 and 80 mg for days 2 and 3 ) .
it is generally combined with a serotonin antagonist ( 5-ht3 ) and dexamethasone . to improve compliance ,
this is given as a single dose on day 1 of chemotherapy as a 150 mg intravenous infusion .
that single dose is able to block 90% of nk-1 receptors.21,23 a study by celio et al21 compared fosaprepitant and aprepitant in the management of acute and delayed cinv among patients treated with high - dose cisplatin .
both agents are highly efficacious for delayed cinv ( nausea and vomiting after 24 hours of chemotherapy).21 a randomized , double - blind trial involving 2,322 patients receiving a cisplatin dose of > 70 mg / m compared aprepitant ( with ondansetron and dexamethasone ) and fosaprepitant ( with ondansetron and dexamethasone ) .
the results showed that a single dose of fosaprepitant was noninferior to a 3-day course of aprepitant.23 a 5-day course of aprepitant was compared with a single dose of fosaprepitant in patients receiving highly emetogenic chemotherapy ( cisplatin dose > 60 mg / m ) .
there was no significant difference in the efficacy of the incidence of nausea and vomiting 7 days after chemotherapy between the two groups.24 fosaprepitant has been compared to serotonin antagonist ( 5-ht3 ) dexamethasone combination , the most common regimen used to treat cinv . a phase iii randomized double - blind study compared a fosaprepitant regimen in combination with granisetron and dexamethasone vs granisetron and dexamethasone only .
the end point of the study was a complete response defined as total absence of nausea and vomiting after a high dose of cisplatin .
overall , the fosaprepitant group had better complete response results ( 64% vs 47% ) .
fosaprepitant is effective in preventing both acute and delayed cinv , with a complete response of 94% and 65% , respectively.25 weinstein et al26 studied the use of a single - dose fosaprepitant vs ondansetron with dexamethasone for the prevention of cinv .
there was no significant difference in the complete response in the acute phase ( 93.2% vs 91% ) .
however , in the delayed phase , fosaprepitant achieved higher complete response rates ( 78.9% vs 68.5% ; p<0.001).26 a study involving the use of aprepitant or fosaprepitant combined with a 5-ht3 antagonist and dexamethasone in colorectal cancer patients receiving oxaliplatin - based chemotherapy showed that the aprepitant / fosaprepitant group achieved better antiemetic outcomes in the overall response rate and prevention of delayed cinv.27 kitayama et al28 did a prospective randomized crossover study to evaluate the efficacy of palonosetron with dexamethasone vs fosaprepitant with granisetron and dexamethasone in the prevention of cinv among patients receiving moderately emetogenic chemotherapy and found no significant difference between the two groups . taking into account all these data , fosaprepitant is effective in the management of cinv , particularly for patients receiving moderately and highly emetogenic chemotherapy .
an important benefit is the ability of this medication to control delayed cinv that can develop in the days after chemotherapy administration ( table 4).5
these usually include anorexia , constipation , nausea , vomiting , diarrhea , hiccups , and asthenia .
23,25 in a study evaluating a single dose of fosaprepitant for the prevention of cinv that included 1,143 patients receiving the drug , the most commonly noted side effects included constipation ( 10.6% ) , asthenia ( 8.6% ) , diarrhea ( 7.8% ) , and vomiting ( 6.6%).23 these adverse events were not significantly different from that of aprepitant .
the study of saito et al25 that compared a fosaprepitant regimen to that of granisetron revealed that the most common adverse event of fosaprepitant was leukopenia , which accounted for 59.2% ( 103 out of 174 ) followed by anorexia ( 51.7% ) and nausea ( 43.7% ) .
one study showed that 23.6% of patients receiving fosaprepitant developed an infusion site reaction.25 these reactions include pain , erythema , swelling , extravasation , and phlebitis.29 in several studies , infusion site reactions have been associated with infusion of anthracycline - based chemotherapy . in a study by sato
et al,30 fosaprepitant coadministered with an anthracycline - based regimen was associated with a higher incidence ( 67% ) of infusion site reaction compared to regimens without anthracycline ( 16% ) .
a comparison of fosaprepitant infusion with anthracycline vs a cisplatin - based regimen showed that the former resulted in significantly higher infusion site reaction with an odds ratio of 12.95.31 in a study comparing fosaprepitant versus aprepitant when administered with the combined doxorubicin and cyclophosphamide , fosaprepitant resulted in higher infusion site reaction , 34.7% vs 2.3%.32 the mechanism of fosaprepitant - induced venous toxicity with an anthracycline - based regimen is poorly understood .
a possible hypothesis is that both anthracycline chemotherapy and fosaprepitant cause impaired endothelial function , thus leading to venous toxicity.33 thus , fosaprepitant should be avoided in patients receiving anthracycline , if possible .
otherwise , it should be administered with intravenous fluids in a proximal peripheral venous site as it has been associated with decreased chances of infusion site reaction.34 there have been no studies looking into fosaprepitant administration through a central venous access .
fosaprepitant has been approved for the prevention and treatment of cinv caused by moderately and highly emetogenic chemotherapy .
dexamethasone drug combination and is noninferior to aprepitant in the management of cinv . with single dosing ,
infusion site reaction is a major side effect , especially when administered with an anthracycline - based regimen .
infusing in a more proximal peripheral site and with intravenous fluids appears to decrease the chances of venous toxicity . | ### Summary:
: chemotherapy - induced nausea and vomiting ( cinv ) is a debilitating side effect of antineoplastic agents .
several treatment regimens are used to address this problem .
fosaprepitant is a neurokinin-1 receptor blocker used in the prevention and treatment of cinv , especially for moderately and severely emetogenic chemotherapy .
it is highly effective in the treatment of delayed cinv .
data from previous studies show that fosaprepitant is noninferior to aprepitant in the management of cinv .
fosaprepitant is given as a single - dose intravenous infusion , thus offering better patient compliance .
the dose - limiting side effect of fosaprepitant is an infusion - related reaction , ranging from pain at the infusion site to thrombophlebitis .
this side effect has been reported with coadministration of anthracycline agents . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: litten first described an intraretinal hemorrhage associated with subarachnoid hemorrhage ( sah ) in the german literature .
however , terson 's description of vitreous hemorrhage ( vh ) following sah in 1900 is now associated with this syndrome . in terson 's syndrome ( ts ) , intracranial hemorrhages ( ich ) are followed by intraocular hemorrhage ( ioh ) , classically in the subhyaloidal space , but may also include subretinal , retinal , preretinal , and vitreal collections .
very few reports of organic depression and ts in autosomal dominant ( adult ) polycystic kidney disease ( adpkd ) are reported in the literature .
adpkd is a common ( 1:400 - 1:1000 ) disease seen in fourth decade , characterized by bilateral multiple expanding renal cysts , associated with hypertension ( 75% ) , mitral valve prolapse ( 20 - 25% ) , saccular aneurysms of circle of willis ( 10 - 30% ) , and asymptomatic liver cysts ( 40% ) .
such associations may pose patients at risk for sah or rarely subdural hemorrhage ( sdh ) and subsequent ts .
cerebrovascular disease may predispose , precipitate , or perpetuate some geriatric depressive syndromes that resemble primary depressions both clinically and therapeutically in about half of the patients following acute stroke .
we report an unusual case of organic depression and ts in a hypertensive middle - aged lady with adpkd , following anterior communicating artery ( acoa ) aneurysmal sah , with full remission of depressive symptoms after post - neurosurgical interventions .
we also summarize the relevant literature as identified via pubmed , embase , and psycinfo , as well as reference sections of selected articles .
a 50-year - old lady , receiving treatment for hypertension for the past 8 years , was diagnosed as having comorbid organic depression as per icd-10 diagnostic criteria , and was symptomatic for the past 4 months .
she was managed with escitalopram ( 10 mg / day ) and mirtazapine ( 15 mg / day ) , but was in partial remission .
she presented to the psychiatry out - patient services with exacerbation of symptoms of pervasive depression , apathy , insomnia , anorexia , fatigue , reduced social interactions , and frontal headache for the past 4 months , with diminished vision and vomiting for the past 1 week .
episodic frontal headache was followed by unresponsiveness and sudden fall without tonic clonic limb movements or injuries , lasting for about 10 min with amnesia for the event .
she had no history of head trauma , epilepsy , substance ( alcohol , nicotine , or drug ) abuse , or psychosocial stressors .
family history of late - onset kidney diseases and hypertension was noted in both her parents and adpkd was diagnosed in both her sons . on admission ,
the glasgow coma scale score was e4v5m6 and hunt hess scale was grade-1 , with blood pressure of 190/110 mm hg .
mental status examination revealed depressed mood , apathy , negative cognitions , impaired judgment with preserved attention , orientation , memory , and intelligence , with grade-4 insight .
hamilton depression rating ( hamd-17 item ) score was 16 and the score on the mini - mental status examination was 28/30 .
ophthalmological evaluation revealed reduced visual acuity in the right eye ( 1/60 ) and normal left eye ( 6/6 ) , bilaterally normal anterior segments , normal pupils ( bilaterally 3 mm , round , regular , and reacting to both direct and consensual light reflexes ) , and normal intraocular pressures .
fundoscopy showed boat - shaped subhyaloid hemorrhage involving the posterior pole extending below the inferior arcade , with multiple hemorrhages seen around the normal optic disc in the right eye [ figure 1a ] and normal left fundus [ figure 1b ] , with evidence of bilateral grade-1 hypertensive retinopathy [ figure 1 ] .
hematological and biochemical investigations revealed moderate normocytic and normochromic anemia ( hemoglobin 8.7 g / dl ) , mild leukocytosis ( 12,240/mm ) , raised serum creatinine ( 2.5 mg / dl ) with normal blood urea ( 42 mg / dl ) , serum electrolytes , blood glucose , lipid , liver , and thyroid profiles .
ultrasonography ( usg ) of abdomen showed bilateral renal ill - defined multiple ( > 6 ) cysts and calculi [ figure 2 ] .
electroencephalography showed right frontal polyspikes and sharp waves with preserved alpha background activity suggestive of epileptogenic foci .
cranial magnetic resonance imaging ( mri ) revealed minimal sah in the anterior inter - hemispheric fissure and adjacent cortical sulci with edema in adjacent frontal lobes , and hyper - acute sdh in bilateral fronto - temporo - parietal regions along the cerebral convexities ( 5 mm ) , with no mass effect or midline shift [ figure 3a ] , confirming the diagnosis of ts .
cerebral angiography showed small bi - lobed aneurysm ( 6 6 4 mm ) arising from the acoa with the neck of aneurysm measuring 1.5 mm in medio - lateral direction [ figure 3b ] .
( a ) right fundus montage showing subhyaloid hemorrhage in boat - shaped pattern with multiple blotch hemorrhages and grade-1 hypertensive retinopathy changes .
( b ) left fundus showing grade-1 hypertensive retinopathy changes with absence of intraocular hemorrhages ultrasonography of abdomen showing bilateral renal illdefined multiple ( > 6 ) cysts and calculi ( a ) cranial magnetic resonance imaging showing minimal subarachnoid hemorrhage in the anterior inter - hemispheric fissure and adjacent cortical sulci with edema in adjacent frontal lobes , and hyperacute subdural hemorrhage in bilateral fronto - temporo - parietal regions along the cerebral convexities ( 5 mm ) , with no mass effect or midline shift .
( b ) magnetic resonance angiography showing a small aneurysm ( 6 6 4 mm ) arising from the anterior communicating artery , with the neck of aneurysm measuring 1.5 mm in medio - lateral direction management included anti - hypertensives , antiepileptics , zolpidem , and hematonics .
neodymium : yag ( nd : yag ) laser posterior hyaloidotomy was performed by transcorneal route using frequency doubled nd : yag laser 532 nm ( zeiss - visulas yag laser 532 nm ; laser setting : 9 spots , 100 msec duration , 50 m spot size for penetration burn , 130 mw power ) delivered via a slit lamp using goldmann lens .
the aiming beam was focused on the sloping edge of the most dependent portion of posterior hyaloid membrane at the inferior edge of subhyaloid hemorrhage to facilitate gravity - induced drainage .
patient was advised for head - end elevation , and later discharged with anti - hypertensives , antiepileptics , and zolpidem . a week later , near - complete resolution of subhyaloid hemorrhage [ figure 4a ] and ich , with mild ventriculomegaly [ figure 4b ] was noted .
a month later , aneurysm clipping was successfully done by the neurosurgeon in liaison with a nephrologist .
a month later , patient was asymptomatic with hamd-17 score of 3 , and was regularly followed up for a year following neurosurgical intervention .
she remained euthymic without any active psychiatric interventions and was managed with antihypertensives and antiepileptics alone .
this sequential presentation with full remission of symptoms following neurosurgical interventions led to the diagnosis of possible organic depression due to intracranial acoa aneurysm as per icd-10 diagnostic criteria .
( a ) right fundus montage showing complete resolution of subhyaloid hemorrhage with resolving blotch hemorrhages , a week following nd : yag laser photocoagulation .
( b ) cranial computed tomography showing near - complete resolution of intracranial hemorrhages with mild enlargement of lateral and third ventricles
in our case , comorbid hypertension , depression , vomiting , akinetic seizures , and the chronology of presentation led to the suspicion of possible organicity .
presence of sah and symmetric bilateral sdh led to the suspicion of acoa aneurysm , confirmed by neuroimaging .
furthermore , findings of polycystic kidneys on usg , raised creatinine , hypertension , and spontaneous ( non - traumatic ) sah with sdh following aneurysmal rupture in the 50-year - old female led to the strong suspicion of a possible case of adpkd .
temporal association of depressive symptoms with aneurysmal growth and rupture , followed by post - neurosurgical complete remission of depressive symptoms without antidepressant therapy possibly suggests the organic nature of depression .
disruption of prefrontal systems or their modulating pathways by single lesions or by an accumulation of lesions exceeding a threshold is hypothesized to be the central mechanism in vascular depression .
although vascular lesions in the left anterior cortex are found to be associated with a significantly higher frequency of major depression than the lesions in other locations , right - sided lesions may also predispose to retarded depression , as seen in our case .
the most common cause of spontaneous ( non - traumatic ) sah is the rupture of a saccular aneurysm that originates 80% in the anterior and 20% in the posterior circulation .
saccular aneurysms enlarge with time , with the greatest risk for rupture at diameters of 6 - 10 mm .
acoa or middle cerebral artery bifurcation berry aneurysms may rupture into the adjacent brain or subdural space and sometimes form a hematoma large enough to produce mass effect .
surprisingly , in our case , there was minimal aneurysmal bleed with absent neurological signs , preserved mental status , and complete resolution of hemorrhage in 2 weeks , but for seizures , depression , and ts .
the most common cause of ts is sah due to ruptured cerebral aneurysm , while other causes include strangulation , traumatic ich , and post - surgical ich .
most patients with ts are comatose on initial presentation , depending upon the severity of the sah as per the hunt hess classification system .
ioh may be difficult to diagnose immediately because the ophthalmologist is restricted from dilating the pupil in a comatose patient .
a decreased red reflex is helpful in evaluating a comatose patient and b - scan ultrasound can further establish the extent of vh .
firstly , subarachnoid blood is pressed through the optic nerve sheath into the interior of the eyeball when a bleeding episode occurs .
the second theory , which has been most accepted , suggests that vh is the result of venous hypertension and rupture of superficial retinal veins , secondary to abruptly raised intracranial pressure , transmitted through the optic nerve sheath to the swollen optic nerve head , thereby occluding the retinal and choroidal anastomoses at the level of the lamina cribrosa .
this theory is supported by the clinical findings of ioh and significant papilledema occurring in the eye contralateral to the side on which the ruptured aneurysm occurs . however ,
in our case , no such findings were noted on the contralateral side , thus supporting the first theory . in our case , we preferred frequency doubled nd : yag laser ( 532 nm ) over the standard nd : yag laser ( 1064 nm ) due to its focusing capability , less scattering in the ocular media , high absorption by hemorrhage , and excellent delivery system .
spontaneous remission of vh or small ioh is most common , while complete resolution of such hemorrhages may take up to 9 months .
immediate vitrectomy for ioh is not recommended , except in cases of submacular hemorrhage , monocular with severe visual loss , or in pediatric patients at risk for amblyopia . in patients who refuse surgery , repeated visual testing and ultrasound examinations
patients with sah / sdh need a detailed fundoscopic examination for ioh to prevent long - term visual loss .
evaluation of late - onset depression and hypertensive patients for comorbid adpkd may lead to possible clues of intracranial aneurysms . | ### Summary:
: depressive symptoms are common in neurological diseases , at times posing dilemma in organic or functional origin .
cerebrovascular disease may predispose , precipitate , or perpetuate some geriatric depressive syndromes that resemble primary depressions both clinically and therapeutically in about half of the patients following acute stroke .
terson 's syndrome is the direct occurrence of vitreous hemorrhage following subarachnoid / subdural hemorrhage , often overlooked in the acute setting .
autosomal dominant ( adult ) polycystic kidney disease may be associated with berry aneurysms and hypertension , and may lead to intracranial bleeds .
we report an unusual case of organic depression and terson 's syndrome in a 50-year - old female with polycystic kidney disease and hypertension , following anterior communicating artery aneurysmal subarachnoid bleed with bilateral subdural extension .
management included anti - hypertensives , antiepileptics , neodymium : yag laser photocoagulation , and aneurysmal clipping . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: a 46-year - old african american male was brought to the emergency department ( ed ) by helicopter at 3:00 a.m. on a cold january morning .
it was reported that the patient had an altered level of consciousness and was found lying in the middle of a street in wet clothes . he was also noted to have a strong smell of alcohol .
however , he had a glasgow coma scale score of 13 initially because he was disoriented and using inappropriate words . on physical examination
, he appeared to be a well - developed , well - nourished african - american male .
his vital signs included a heart rate of 70 bpm ( sinus rhythm ) , a respiratory rate of 12/min , a blood pressure of 115/71 mmhg , and a pulse oximetry of 96% on 2 l of oxygen via nasal cannula .
following removal of his wet clothes , his core temperature was found to be 29.4c ( 85f ) via a rectal probe .
this patient was found to have swelling on his left maxilla with a superficial laceration and no active bleeding .
warm blankets including a warm air blanket ( bair hugger ) were applied to the patient .
in addition , warm normal saline ( ns ) was administered intravenously , and a foley catheter was placed for warm ns irrigation . a rectal temperature probe was placed for continuous core temperature monitoring . on presentation ,
1 ) showing significant st segment depression in leads ii , iii , avf and v3 - 6 .
laboratory tests were obtained , revealing a high blood alcohol level , a mild elevation of wbc ( 11.42 k/l ) , high anion gap ( 19 mmol / l ) , low bicarbonate ( 14 mmol / l ) , and mildly elevated cpk ( 3,010
otherwise , laboratory results were unremarkable , including two normal troponin i values ( first 0.03 ng / ml and 0.04 ng / ml 2 h after ) and negative urine drug screen test .
the patient had computed tomography of his head , which was negative for fracture or intracranial abnormalities .
1diffuse significant st segment depression in leads ii , iii , avf and v3 - 6 in a patient with core body temperature of 85f diffuse significant st segment depression in leads ii , iii , avf and v3 - 6 in a patient with core body temperature of 85f after aggressive external warming , the patient s core temperature reached 33.9c ( 93f ) and an ekg was repeated ( fig . 2 ) .
the patient was stabilized in the ed and admitted to the hospital for further evaluation and treatment .
2sinus tachycardia with no st segment depression in the same patient with core body temperature of 93f after 2 h of external warming sinus tachycardia with no st segment depression in the same patient with core body temperature of 93f after 2 h of external warming
sinus bradycardia , junctional bradycardia , atrial fibrillation , qt prolongation , pr prolongation , widening of the qrs complex and osborne waves ( j waves ) are the most common ekg changes .
moderate hypothermia is usually considered when core body temperature drops to 32c ( 90f ) , and severe hypothermia is defined as body core temperature below 28c ( 82f ) .
however , it develops most commonly in moderate or severe hypothermia when pacemaker cells decrease depolarization spontaneously
. heart rate can drop over 40% from its baseline when body temperature becomes moderately hypothermic and drop over 55% if it reaches severe hypothermia in animal study .
pathophysiologically , hypothermia depresses the calcium - dependent atpase ( ca - atpase ) activity by reducing the number of active calcium pump units .
the depression of calcium uptake activity delays the inward calcium current , thus prolonging the action potential duration resulting in myocardial conduction delay .
conduction delay can also cause pr prolongation and high - degree a - v blockage in ekg .
increased calcium concentration extracellularly and decreased calcium concentration intracellularly among myocardial cells impairs the cardiac contractility and subsequently reduces the cardiac output .
the na+/h+ exchange function was also affected by hypothermia , with delayed activation of the inward sodium current and more h+ retained intracellularly [ 5 , 6 ] .
the increasing acidosis in the cytosol further affects the enzyme activity , which forms a vicious cycle in the metabolism of myocytes during hypothermia .
the mechanisms of atrial fibrillation ( a - fib ) triggered by hypothermia are still not fully understood and probably multifactorial . under the circumstance of hypothermia ,
the sympathetic nervous system is activated with the release of catecholamine . increased sympathetic innervations trigger the initiation of atrial ectopic activity , which can further progress into a - fib .
in addition , acidosis in hypothermia also lowers the threshold of a - fib among these atrial myocytes .
a - fib occurs more often when core body temperature drops below 32c ( 90f ) .
the qt interval is measured from the time when ventricular myocytes depolarize to the time when they repolarize .
pathophysiologically , hypothermia depresses the pacemaker cells automaticity , affecting the transmembrane ion channel activity , resulting in lower calcium , higher potassium and higher hydrogen levels intracellularly . a shift of these ions from extracellular to intracellular enables hypokalemia to occur more easily around myocytes , which further suppresses the resting membrane potential and induces the qt prolongation .
it is reported that over 70% of hypothermia patients develop qt prolongation . a good linear correlation between the core temperature and the duration of qt interval
is seen in animal studies ; however , it shows significant variability in human beings [ 10 , 11 ] .
osborne waves are detected in 80% of patients with a core body temperature below 30c ( 86f ) , usually occurring in the precordial leads [ 12 , 13 ] .
the appearance of osborn waves on ekg was considered to be due to the abnormalities during early ventricular repolarization , and this may be related to the altered transmural action potential . however , the mechanisms are still not fully understood .
osborne waves can be seen in subarachnoid hemorrhage , myocardial ischemia or sepsis patients , and therefore may not be pathognomonic for hypothermia [ 1518 ] .
st segment elevation can be seen in hypothermia patients often with the appearance of osborne waves because it is partially buried in the r wave with down - sloping st elevation . if it occurs in leads v1 and v2 , st elevation with osborn waves can resemble the brugada syndrome [ 19 , 20 ] .
one of the mechanisms of the st change can be attributed to early repolarization and acidosis . whether the early repolarization is considered benign or malignant
if the early repolarization pattern displays only in the lateral precordial leads , it is usually benign .
however , if it displays in the inferior , lateral and right precordial leads , this can often develop into malignant arrhythmias and ventricular fibrillation .
in one prospective , multicenter observational study , st depression was reported in 17.8% ( 13/73 ) of patients with hypothermia .
unfortunately , this study does not report the amplitude of st depression , the number of leads involved and the relationship to the severity of hypothermia .
one case report was published and reported st depression only from lead v3 to v6 with the appearance of an osborn wave occurring in an 80-year - old woman with a core body temperature of less than 30c ( 86f ) , and st depression was recovered after rewarming . however , until now , the mechanism(s ) of st depression in hypothermia is still uncertain .
it can be seen in normal patients including those with av reciprocating tachycardia , atrial repolarization and hyperventilation , and can be caused by artifacts [ 2426 ] . in patients at high risk of coronary artery disease
subendocardial ischemia can manifest as horizontal or down - sloping st segment depression [ 27 , 28 ] .
other causes of st depression include a digoxin effect , hypokalemia , obstructive sleep apnea syndrome , hypertension , cns diseases , rheumatoid arthritis , mitral valve prolapse and intraventricular conduction abnormalities [ 2936 ] . here
we report a previously healthy young male who developed diffuse st depression when his core body temperature dropped to 29.4c ( 85f ) .
this patient had significant st segment depression of more than 1 mm ( 0.1 mv ) at the j point on leads ii , iii , avf and v3 - 6 ( fig .
the st segment depression presented as a downward slope towards the end of the st segment at its junction with the t wave .
this patient had no past medical history and was not on any medications that could have accounted for these ekg changes .
coronary artery disease is a very unlikely cause of this patient s ekg changes , given his age and lack of cardiovascular risk factors .
furthermore , during his ed stay , his cardiac enzymes were negative , and his st segment changes resolved with rewarming .
his repeat ekg after body temperature reached 33.9c ( 93f ) and showed sinus tachycardia with no st depression in all 12 leads ( fig . 2 ) .
this patient was observed in the hospital overnight and discharged the next day with no observed short - term complications . in conclusion , in this case report , st depression can be the only ekg change in hypothermia that can display globally in the inferior and lateral precordial leads .
fortunately , this ekg change in hypothermia seems to be associated with a good outcome after rewarming . | ### Summary:
: hypothermia is known to cause specific electrocardiographic ( ekg ) changes such as osborne waves and bradycardia .
we report diffuse st segment depression , an atypical ekg change , in a patient with a core temperature of 29.4c ( 85f ) .
this patient had no previous cardiovascular pathology , and his ekg changes resolved gradually with aggressive warming .
we also discuss the pathophysiology and clinical significance of st depression in the general population and the typical ekg changes in hypothermia patients . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: microbial ecosystems require energy for maintenance and prosperity . on land and in the sea surface ,
photoautotrophs ( e.g. , plants and cyanobacteria ) are the primary producers that fix inorganic carbon and transform it into organic carbon using solar energy .
the resulting organic carbon supports the growth of various organisms as carbon and energy sources .
in contrast , there are microbial ecosystems that are sustained by chemical energy derived from inorganic redox reactions between electron donors ( such as h2 , h2s , fe , and ch4 ) and acceptors ( such as o2 , no3- , fe , so42- , and co2 ) .
it is known that chemosynthetic ecosystems are widely distributed on land ( e.g. , acid mines , hot springs , and deep subsurface ) and in oceans ( e.g. , cold seeps , hydrothermal vents , and potentially enormous sub - seafloor aquifers ) .
recently , much attention has been paid to deep - sea hydrothermal vents and sub - seafloor aquifers that are potential habitats harboring extensive chemosynthetic ecosystems sustained by a variety of chemolithoautotrophs ( reviewed in orcutt et al . , 2011 ) . although the precise picture of the potentially enormous sub - seafloor biosphere is still not well understood , the elucidation of the distribution , function , activity , and productivity of the deep - sea chemosynthetic ecosystems is important for better understanding not only of the extent and limit of the biosphere on earth but also the global cycling of elements related to biological activities .
deep - sea hydrothermal vent fields were initially found in the late 1970s . to date , over 200 deep - sea hydrothermal fields have been found in various areas , mainly on mid - ocean ridges , arc volcanoes , back - arc basins , and hot - spot volcanoes ( http://www.interridge.org/irvents/ ) .
the hydrothermal fluids contain a variety of electron donors that serve as energy sources for the life thriving there .
the chemical disequilibria , which occur in deep - sea hydrothermal environments by rapid mixing of reduced hydrothermal fluids with oxygenated cold seawater , could provide energy sources for the growth of the chemolithoautotrophs ( mccollom and shock , 1997 ; takai and nakamura , 2010 ; amend et al . , 2011 ) .
in fact , the presence of hydrogen- , sulfide- , and methane - oxidizers was confirmed soon after the discovery of the vent field ( jannasch and mottl , 1985 ) .
subsequent studies have revealed the ecology of the chemolithoautotrophs inhabiting the deep - sea hydrothermal vent fields , which include mesophiles to hyperthermophiles belonging to the epsilonproteobacteria , gammaproteobacteria , and archaea ( nakagawa and takai , 2008 ) .
in contrast to hydrogen- , sulfide- , and methane - oxidizers , our knowledge of iron - oxidizers , especially mesophilic and neutrophilic bacteria , in deep - sea hydrothermal fields has been quite limited and was reported only recently .
the first neutrophilic , mesophilic , and iron - oxidizing chemolithoautotrophic marine bacterium , mariprofundus
ferrooxydans , which belongs to the zetaproteobacteria , was isolated from iron - rich mats in the hydrothermal fields of the loihi seamount ( emerson et al . , 2007 ) , and the genome sequence of m. ferrooxydans was recently reported ( singer et al . , 2011 ) .
this isolate produces unique helical - stalks consisting of organic compounds and iron oxides ( chan et al . , 2011 ) .
it is thus reasonable to consider that the iron - oxidizers play a significant role in the generation of massive iron - rich mats on the seafloor ( emerson and moyer , 2002 ) .
diverse 16s rrna gene sequences affiliated in the zetaproteobacteria have been recovered from iron - rich mats from various marine hydrothermal fields ( mcallister et al . , 2011 ) .
in some cases , members of the zetaproteobacteria dominate the communities in the iron - rich mats ( kato et al .
, 2009a ) and in the sub - seafloor warm fluids ( kato et al . , 2009b ) ,
although the physiology of these phylotypes in the zetaproteobacteria is still unclear because few isolates have been reported . considering the domination of the zetaproteobacteria and the abundance of the unique stalk structures in the seafloor massive iron oxide mats , it is very likely that the zetaproteobacteria contain many iron - oxidizing chemolithoautotrophic species , sustaining the iron - based microbial ecosystem present in the iron - rich mats . in the deep - sea hydrothermal vent fields , sulfide deposits ( like mounds and chimneys ) are usually present and sulfide- and hydrogen - oxidizers
the detection of sulfide- and hydrogen - oxidizers in these habitats is consistent with the high potential of bioavailable energy from sulfide- and hydrogen - oxidation reactions in chemical conditions of the habitats ( takai and nakamura , 2010 ; amend et al .
in contrast , iron - rich mats are not always observed in deep - sea hydrothermal vent fields , and the zetaproteobacterial phylotypes ( putative iron - oxidizers ) were relatively abundant , compared to the known sulfide- and hydrogen - oxidizers , only in the iron - rich mats and crustal fluids ( kato et al .
a comprehensive and comparative analysis is needed to answer the following question : what is the critical factor(s ) for the appearance of iron - based microbial ecosystems .
this information is important in order to understand global carbon and iron cycling because iron - based microbial ecosystems are potentially present in enormous sub - seafloor aquifers , which would be the largest chemosynthetic ecosystem on earth ( bach and edwards , 2003 ; edwards et al . , 2003 ) .
the southern mariana trough ( smt ; figure a1a in appendix ) is one of the most suitable fields in which assess the factors leading to the appearance of iron - based microbial ecosystems . in the smt , there are variable temperature habitats , from black and clear smoker sulfide chimneys ( up to 340c ) to iron - rich mats with shimmering ( 110c ; figure 1 ) , in an area of 5 km 5 km ( figure a1b in appendix ) .
furthermore , there are several boreholes that were drilled using a shallow - seafloor drilling instrument , benthic multi - coring system ( bms ; marumo et al .
analysis of the collected fluids from the boreholes can provide valuable information about the geochemical conditions and microbiological activities of the sub - seafloor aquifers .
davis and moyer ( 2008 ) first reported the presence of the zetaproteobacteria in iron - rich mats in the smt .
sequentially , comprehensive microbiological analyses of the various samples from the smt hydrothermal fields have been done ( kato et al .
we summarize the variation of microbial communities in the smt as shown by culture - independent molecular microbiological analyses , and discuss how these community structures were constructed .
in addition , the bioavailable energy yields based on thermodynamic calculations were applied to discuss the geochemical factors leading to the appearance of the iron - based microbial ecosystem .
( a ) a black smoker chimney at the archaean site , ( b ) a black smoker chimney at the pika site , ( c ) diffuse flows from crack of pillow lavas at the snail site , ( d ) iron - rich mats at the snail site , and ( e ) a casing pipe inserted into a borehole at the snail site .
the smt is a spreading back - arc basin that is located at the southern extension of the izu
bonin arc , western pacific ( figure a1a in appendix ; fryer , 1995 ; ishibashi and urabe , 1995 ) .
hydrothermal activity hosted by basaltic rocks ( kakegawa et al . , 2008 ) was found on the back - arc spreading ridge ( snail site ) and on the off - ridge seamounts ( pika and archaean sites ) in the smt ( figure a1b in appendix ; wheat et al . , 2003 ; ishibashi et al . , 2004 , 2006 ) .
in the pika and archaean sites , sulfide chimneys venting high temperature fluids ( up to >
low - temperature diffusing and shimmering fluids ( < 150c ) were also observed in both sites . in the snail site ,
diffuse flows or shimmering with relatively low - temperature hydrothermal fluids ( < 120c ) from the fractures of pillow lavas ( basalts ; figure 1c ) and iron - rich mats ( containing fe , si , and mn ; figure 1d ) were also observed ( wheat et al . , 2003 ;
, although chimney - like sulfide structures and associated high temperature hydrothermal venting have not been found .
boreholes were created on the seafloor at the snail and pika sites using bms ( marumo et al .
these boreholes were cased with titanium pipes ( figure 1e ) . during fluid sampling from the boreholes ,
preliminarily analyses of the geochemical composition of hydrothermal fluids collected in the smt hydrothermal fields in 2003 , 2004 , and 2005 have been reported ( wheat et al . , 2003 ; ishibashi et al . , 2004 , 2006 ) .
furthermore , we collected hydrothermal fluids from natural vents and boreholes in the smt in 2010 and analyzed the fluid geochemistry as previously described ( takai et al .
concentrations of o2 , co2 , ch4 , and h2 in deep seawater were referred from the previous publication ( mccollom , 2007 ) . it should be noted that a significant difference in the ratio of fe to h2s was observed among the vent samples collected from the snail site ( figure 2 ) .
these samples were divided into fe - type ( high fe / h2s ) and h2s - type ( low fe / h2s ) and their geochemical data are shown in separate columns in table a1 in appendix . the ratio of fe to h2s in fluid samples .
the concentrations of cl , si , h2s , and fe are plotted against its mg concentration ( figure 3 ) .
these so - called magnesium diagrams are conventionally used to estimate the hydrothermal end - member composition of a high temperature fluid from the deep - sea hydrothermal system ( von damm et al . , 1985 ) .
the collected fluid sample is often conceived to be simple mixture between the hydrothermal end - member ( completely depleted in mg ) and seawater ( mg concentration is rather high as 50 mm ) . for conservative chemical species in mixing between the hydrothermal end - member and seawater
mg diagrams against cl , si , h2s , and fe for fluid samples . ( a )
cl mg , ( b ) si mg , ( c ) h2s mg , and ( d ) fe mg diagrams are shown . nv and bh indicate natural vents and borehole fluids , respectively .
chloride is predominant anion of hydrothermal fluid and seawater , which is a representative for such conservative species . in cl
mg diagram ( figure 3a ) , plots of the collected samples from the pika and archaean sites show clearly different trends . substantial deviation of cl concentration of hydrothermal fluid from that of seawater is attributed to sub - seafloor phase separation ( e.g. , takai et al . , 2008 ) .
based on the data of high temperature ( > 150c ) fluids , cl - enriched signature of the pika fluid can be classified as vapor - lost ( i.e. , the gases such as h2 , h2s , and ch4 are poor ) hydrothermal fluid . in contrast , cl - depleted signature of the archaean fluid can be classified as vapor - rich ( i.e. , the gases are enriched ) hydrothermal fluid . in the archaean site ,
the collected sample of low - temperature ( < 150c ) shimmering was enriched in h2 and ch4 ( table a1 in appendix ) , which is in accordance with occurrence of vapor - rich hydrothermal fluid in this site .
si concentration of hydrothermal fluid is known as controlled by fluid - mineral equilibrium at the fluid reservoir ( von damm et al . , 1991 ) .
the si mg diagram ( figure 3b ) suggests si concentrations of the hydrothermal fluid end - members for three sites are commonly as high as 16 mm , which corresponds to equilibrium at high temperature condition above 300c .
this result is reasonable for the pika and archaean fluids , since such high temperature fluid vents have been observed in these sites .
similar to these two sites , a high temperature fluid reservoir would exist below the seafloor in the snail site .
in fact , the first report for the snail site mentioned that fluid temperature was as high as 250c ( wheat et al . , 2003 ) .
significantly high h2s and fe concentrations were observed for the samples collected from high temperature fluid vents in both pika and archaean sites ( table a1 in appendix ) . based on analogy to the high temperature fluids found at hydrothermal fields in lau basin , low ph signature of the fluid
could be responsible for enrichment in these species ( takai et al . , 2008 ) .
in contrast , h2s and fe concentrations of the low - temperature fluid samples are noticeably lower than the mixing line between high temperature fluids and seawater ( figures 3c , d ) .
it is likely that iron - sulfide mineral precipitation occurred during sub - seafloor mixing , causing the decrease of h2s and fe concentrations in the low - temperature fluids .
for the snail site , it is difficult to estimate original h2s and fe concentrations in the fluid reservoir , since no high temperature fluid venting was observed .
however , it is reasonable to expect similar range to other two sites , since common si concentration among three sites suggest existence of a high temperature fluid reservoir . if it is the case , the observed fe and h2s concentrations of the samples collected from low - temperature shimmering can be interpreted as affected by mineral precipitation during sub - seafloor mixing between the high temperature fluid and seawater
the microbial community structures in various habitats ( e.g. , sulfide structures of active vents , iron - rich mats , borehole fluids , and ambient seawater ; figure 1 ) in the smt have been investigated using culture - independent molecular microbiological methods ( pcr clone library construction and dna sequencing , fluorescence in situ hybridization ( fish ) and quantitative real - time pcr ; kato et al . , 2009a , b , 2010 ) .
the bacterial community structures in the habitats have been determined by 16s rrna gene clone library analysis as described in our previous reports ( kato et al .
the relatively abundant taxonomic groups in the libraries for each habitat are summarized in table 1 .
it should be noted that the abundance of the phylotypes in the libraries does not indicate their real abundance in the communities but only the relative abundance due to the inherent biases of pcr - based analyses ( wintzingerode et al . , 1997 ) .
abundant taxonomic groups in the bacterial clone libraries for each habitat . * based on the physiological characteristics inferred from the phylogeny of the phylotypes . in the sulfide structures of active vents , phylotypes belonging to the aquificae or epsilonproteobacteria were abundant in the libraries .
the detection frequencies in the libraries were up to 44% of the total clone numbers .
members of the epsilonproteobacteria have a variety of metabolic and physiological characteristics : hydrogen- and sulfide - oxidation , microaerobic and anaerobic , and mesophilic to thermophilic .
however , no iron - utilizing bacteria have been reported in the two taxonomic groups .
the microbial community structures of these sulfide structures of active vents in the smt were similar to those of each habitat in other deep - sea hydrothermal areas including other back - arc basins , arc volcanoes , and mid - ocean ridges ( takai et al . , 2006 ) .
the abundant phylotypes in the libraries from the seawater samples were different from those of the sulfide structures of active vents .
the phylotypes related to sup05 group and sar11 cluster dominated in the libraries from the seawater samples .
the sup05 group belonging to the gammaproteobacteria predominated in the hydrothermal plume of the suiyo seamount ( sunamura et al . , 2004 ) and may include sulfide - oxidizing chemolithoautotrophs as suggested by metagenomic analysis ( walsh et al . , 2009 ) .
the bottom seawater samples collected in the smt are likely to be mixed with hydrothermal plumes .
the microbial community structures of the iron - rich mats and borehole fluids were distinguished from those in the chimneys and seawater .
the phylotypes belonging to the zetaproteobacteria were abundant ( up to 50% of the total clone numbers ) in the libraries from the iron - rich mats and borehole fluids .
quantitative pcr or fish analysis indicated that the zetaproteobacteria phylotypes accounted for up to 32% of the total cell numbers in the communities of these samples .
in addition , the phylotypes related to sulfide - oxidizers , such as thiomicrospira in the gammaproteobacteria and sulfurimonas in the epsilonproteobacteria , were also detected in the libraries from the borehole fluids .
in contrast , the phylotypes related to methylomonas and methylophaga ( including methano / methylotrophs ) in the gammaproteobacteria were relatively abundant in the libraries from the iron - rich mats .
davis and moyer ( 2008 ) have also provided 16s rrna gene data from iron - rich mats in snail site .
they also detected the phylotypes related to zetaproteobacteria and gammaproteobacterial methano / methylotrophs , which is consistent with our results .
, 2009a , b , 2010 ) , the bacterial community structures in each habitat ( i.e. , active sulfide structures , iron - rich mats , borehole fluids and ambient seawater ) in the smt were compared by principal coordination analysis ( pcoa ) using fast unifrac ( hamady et al . , 2009 ) .
although davis and moyer ( 2008 ) have also provided 16s rrna gene data from iron - rich mats in snail site , we did not include their data in the comparative analysis to minimize methodological biases accompanied by different experimental procedures ( e.g. , dna extraction and pcr ) .
the distribution pattern of the communities for each sample corresponded well to their habitat types ( figure 4 ) .
the differences in the habitat types resulted in the differences in the abundant phylotypes in the libraries ( table 1 ) .
the physiology of the phylotypes can not be determined from their phylogeny , but only inferred from the closest cultured species ( table 1 ) .
if we assume that the inferred metabolic functions of these phylotypes are correct , the observed differences in the microbial community structures among the habitats can be attributed to the presence / absence of each chemolithoautotroph ( i.e. , hydrogen- , sulfide- , methane- , or iron - oxidizer ) . in principle , the distribution pattern in pcoa is greatly influenced by the presence / absence of phylotypes that are phylogenetically distant from one another .
each axis ( pc1 - 3 ) indicates the first , second , and third principal coordinates .
the percentages in the axis labels represent the percentages of variation explained by the principal coordinates .
afhm1 and 2 , sulfide mound venting 107c fluid at the snail site ; aacs1 - 3 , clear smoker chimney venting 117c fluid at the archaean site ; apbsc1 - 4 , black smoker chimney venting 270c fluid at the pika site ; apcsc1 - 4 , clear smoker chimney venting 19c fluid at the pika site ; ipltcb , g , and o , inactive chimney at pika site ; iydcb , and g , inactive chimney at the y site ; pasw , and fasw , ambient seawater at the pika and snail sites , respectively ; fapm1 and f2apm , borehole fluids at the snail site collected in 2004 and 2005 , respectively ; papm3 , borehole fluids at the pika site ; fnv , natural vent fluid at the snail site ; ys16 and ys18 , iron - rich mats at the kaiko and snail sites , respectively . the data from the y and kaiko sites are not mentioned in the present paper ( please , see kato et al .
in addition to the bacterial communities , diverse archaeal communities were also detected in the habitats in the hydrothermal fields of the smt ( kato et al .
the abundant archaeal taxonomic groups were different among the habitats ( table 2 ) like the bacterial communities .
a large number of the recovered phylotypes were affiliated with uncultured clone groups , such as the miscellaneous crenarchaeotic group ( mcg ) , terrestrial hot spring crenarchaeota ( thsc ) , psl12-related group , and marine benthic group e ( mbge ) .
although the physiologies of these uncultured phylotypes is still unclear , some of them have been inferred from metagenomic and functional gene analyses , and the geochemical characteristics of the environments where they were detected : for example , the mcg includes anaerobic chemoorganotrophs ( teske and srensen , 2008 ) , the psl12-related group includes ammonia - oxidizers ( mincer et al . , 2007 ) , and mbge includes iron - oxidizers ( takai and nakamura , 2010 ) , respectively .
abundant taxonomic groups in the archaeal clone libraries for each habitat . * based on the physiological characteristics inferred from the phylogeny of the phylotypes . in the sulfide structures of active vents , phylotypes related to archaeoglobi , thermoprotei , and thsc were abundant in the libraries .
only marine group i ( mgi ) phylotypes were detected in the libraries from the seawater samples .
mgi members are common archaeal inhabitants in oceans ( fuhrman et al . , 1992 ) and
the group includes an ammonia - oxidizing chemolithoautotrophic isolate ( knneke et al . , 2005 ) . like the bacterial community structures , the archaeal community structures of these sulfide structures and seawater samples were totally similar to those of each habitat in other deep - sea hydrothermal areas including other back - arc basins , arc volcanoes , and mid - ocean ridges ( takai et al . , 2006 ) .
all archaeal phylotypes recovered from the iron - rich mats and borehole fluids were classified in uncultured clone groups , such the mbge , mcg , and psl12-related group .
for example , the mbge phylotypes were first reported from deep - sea sediments ( vetriani et al . , 1999 ) and were detected in iron - rich habitats ( suzuki et al . , 2004 ; takai , 2008 ) .
the mcg phylotypes are one of the widely distributed groups of archaea in deep - sea environments ( teske and srensen , 2008 ) .
interestingly , a mcg phylotype ( ncbi accession number , ab213054 ) was closely related to those detected in crustal fluids from the iodp borehole 1026b ( ay181048 ; cowen et al . , 2003 ) and from the inserting pipes at the baby bare seamount ( ay704375 ; huber et al . , 2006 ) .
this mcg phylotype is potentially an indigenous archaeal member in sub - seafloor crustal aquifers .
archaeal communities have often been ignored in microbiological analysis of iron - rich mats . however , the archaeal abundance in the communities of the smt is not so small ( over 10% ) and should not be ignored ( davis and moyer , 2008 ; kato et al . , 2009a ) .
it is possible that archaeal communities play significant role in elemental cycling of fe , n , and c in iron - rich deep - sea environments , and in the maintenance of the microbial ecosystems .
further cultivation efforts are needed to determine the physiology of these uncultured archaeal groups and to understand their significance in microbial ecosystems and elemental cycling in deep - sea hydrothermal systems .
it has been proposed that fluid geochemistry constrains microbial community structures in deep - sea hydrothermal fields ( mccollom and shock , 1997 ) .
the available chemical energy for chemolithotrophs can be calculated thermodynamically for each metabolic reaction based on the geochemistry of hydrothermal fluids . to assess the relationship between microbial community structures and geochemical composition of hydrothermal fluids in the smt
, we calculated the bioavailable energy yields of metabolic reactions ( aerobic hydrogen- , methane- , sulfide- , ammonia- or iron - oxidation , methanogenesis , sulfate- , iron- or nitrate - reducing hydrogen - oxidation , and anaerobic methane - oxidation ) for each type of hydrothermal fluid , and compared them to the inferred metabolic ability for each taxonomic group from their phylogeny ( tables 1 and 2 ) .
the procedure for the thermodynamic calculation was previously described in detail ( takai and nakamura , 2010 ) . in brief , the amounts of chemical energy potentially available for chemolithotrophic metabolisms in hydrothermal fluid were determined by calculating the gibbs free energy of each of the metabolic reactions . the overall gibbs free energy of reaction can be calculated using the equation : where gr is the gibbs free energy of reaction , gr is the standard state gibbs free energy of reaction , r is the universal gas constant , t is the temperature in kelvin , and q is the activity quotient of the compounds involved in the reaction .
the q term takes into account the contribution of the fluid composition to the gibbs energy of each reaction .
chemical compositions of the hydrothermal fluids used for the calculation are ( i ) the measured data of the low - temperature fluids sampled and ( ii ) the calculated values for low - temperature fluids by mixing between end - member hydrothermal fluids and seawater .
the mixing calculations were performed with the aid of the computer program eq3/6 , version 8.0 ( wolery and jarek , 2003 ) .
the thermodynamic database for the eq3/6 operations and the values of the standard gibbs energy for the chemolithotrophic metabolic reactions ( gr ) were generated using the supcrt92 code ( johnson et al . , 1992 ) with a customized database .
for reproducing the conditions inside of sulfide structures of active vents , the bioavailable energy yields for the temperature range between 3 and 125c were calculated ( figure a2 in appendix ) using the geochemical data of high temperature hydrothermal fluids venting at the pika and archaean sites .
we could not calculate the bioavailable energy yields for the snail site because of lack of data for high temperature vent fluids in that site . in the calculation ,
simple mixing between hydrothermal fluid and seawater without any redox and mineral precipitation reactions was assumed ( takai and nakamura , 2010 ) . the results of the geochemical model calculations show that aerobic sulfide - oxidation yields the highest bioavailable energy under all temperature conditions ( figure a2 in appendix ) .
this suggests that sulfide - oxidizers using o2 and no3- as electron acceptors can dominate in sulfide structures of active vents at both the pika and archaean sites .
indeed , phylotypes related to the epsilonproteobacteria including aerobic sulfide - oxidizing chemolithoautotrophs ( e.g. , sulfurimonas ) were dominant in the libraries from the active chimneys from the pika and archaean sites ( table 1 ) .
this implies that the high - potentials of the energy availability from sulfide - oxidation reactions affect the relative abundance of these sulfide - oxidizing chemolithoautotrophs in bacterial communities in sulfide structures of active vents .
the geochemical modeling results also suggest that iron - oxidation reactions produce the second largest amount of bioavailable energy . in the active chimney samples , however , none of the known iron - oxidizing chemolithoautotrophs was detected .
this may suggest that the uncultured phylotypes detected in the sulfide structures contain unknown iron - oxidizers . to assess the geochemical conditions of the relatively low - temperature ( < 150c ) fluids for chemolithoautotrophic microorganisms at the pika , archaean and snail sites , the bioavailable energy yields were also calculated using the observed chemical data of the low - temperature shimmering fluids from the vent sites .
the calculated bioavailable energy yields show that sulfide - oxidation reactions can produce higher bioavailable energy than other metabolic reactions ( figures 5a , e , f , h ) , except the archaean site where hydrogen- and methane - oxidizing reactions yield higher bioavailable energy than sulfide - oxidation reactions ( figure 5 g ) .
the results are generally consistent with those estimated for vent fluids from active sulfide structures ( figure a2 in appendix ) . regarding the 75115c vent fluids of the archaean site ( figure 5 g ) ,
the bioavailable energy yields from aerobic and anaerobic hydrogen - oxidation reactions are slightly higher than those values estimated for active sulfide structures ( figure a2 in appendix ) due to relatively high h2 concentrations of the low - temperature shimmering fluids ( comparable to high temperature fluids ) .
although the hydrogen concentration of the archaean vent fluids would be variable and fortuitously fluctuating by phase separation and subsequent sub - seafloor mixing , the geochemical modeling result is generally consistent with microbiological observations that putative ( hyper)thermophilic hydrogen - oxidizing chemolithoautotrophs belonging to both domains bacteria ( e.g. , hydrogenimonas ) and archaea ( e.g. , archaeoglobi ) were detected in the archaean site .
bioavailable energy yields for metabolic redox reactions for each sample type . for the snail site
, the energy yields result from ( a ) 15116c natural vent , ( b ) 340c borehole , ( c ) h2s - type , and ( d ) fe - type fluids . for the pika site
, the energy yields result from ( e ) 100c natural vent and ( f ) 350c natural vent fluids .
for the archaean site , the energy yields result from ( g ) 75117c natural vent and ( h ) 30c natural vent fluids . the bioavailable energy yields for ( e ) 100c natural vent in the pika site and for ( h ) 30c natural vent in the archaean site
were calculated using the geochemical data estimated from a simple mixing model of hydrothermal fluids and seawater .
it should be noted that the bioavailable energy yields for iron - oxidation in the borehole fluid and high fe / h2s vent fluids ( i.e. , fe - type fluids ) in the snail site may be comparable to or higher than those for sulfide - oxidation ( figures 5b , d ) . the result is quite different from those estimated by a simple mixing model of high temperature hydrothermal fluids and seawater ( figure a2 in appendix ) and those calculated using the observed chemical data of the other low - temperature shimmering fluids ( figures 5a , c , e
h ) . this leads us to propose that there are habitats of iron - oxidizers where bioavailable energy yields from iron - oxidation reactions may be preferable for chemolithoautotrophs compared to those from sulfide - oxidation reactions .
indeed , the phylotypes related to the zetaproteobacteria including an iron - oxidizing chemolithoautotroph ( m. ferrooxydans ) were abundant in the iron - rich mats accompanied by fe - type vent fluids and the borehole fluids in the smt ( table 1 ; kato et al .
this microbiological result is consistent with the geochemical thermodynamic result showing the presence of habitats with relatively high bioavailable energy yields for iron - oxidation in the snail site .
the same putative iron - oxidizers were also detected in borehole fluid from the pika site .
although h2s and h2 concentration data for the pika borehole fluid are not available and thus bioavailable energy yields for hydrogen- and sulfide - oxidation reactions can not be calculated , fe - rich , and h2s - depleted fluids similar to that observed in the snail site are expected for the pika borehole .
massive iron - rich mats harboring the zetaproteobacteria were found in other hydrothermal fields , such as on arc volcanoes ( forget et al . , 2010 ) , hot - spot volcanoes ( rassa et al . , 2009 ) , and mid - ocean ridges ( davis et al . , 2009 ) .
furthermore , the phylotypes related to the zetaproteobacteria were detected in the basaltic oceanic rocks ( santelli et al . , 2008 ) .
bach and edwards ( 2003 ) have suggested that oxidation of reduced iron contained in the basaltic oceanic crust can provide energy for chemosynthetic ecosystems , which is corresponding to 2 10 g cellular carbon / year as estimated by thermodynamic calculation .
more detailed geochemical microbiological characterization will provide insight into the relationship between the bioavailable energy yields by iron - oxidation and the abundance and distribution of the zetaproteobacteria on and below the seafloor . as shown above , assuming that the vent fluids were simply generated by mixing of end - member hydrothermal fluids with seawater , sulfide - oxidation yields the high energy for chemolithotrophs at all temperature ranges in the smt hydrothermal fields ( figure a2 in appendix ) .
however , in fact , our thermodynamic calculations using the actual geochemical data indicate the presence of habitats in the snail site where relatively high energy yields are available from iron - oxidation rather than sulfide- and hydrogen - oxidation .
this discrepancy between the observation and theoretical expectation may result in part from incomplete modeling of the geochemical composition of the venting fluids as mentioned previously ( amend et al . , 2011 )
; for example , residence time , mineral depositions , and/or microbial metabolisms can influence the geochemistry of actual vent fluids , especially for low - temperature shimmering fluids that are likely to migrate in the crust at a slow rate . in the snail site
, many diffuse flows from cracks of the seafloor basalts were observed ( figure 1c ) , while no black smoker chimneys were found .
in addition , pyrites ( fes2 ) were found in the fractures and vesicles of the sub - seafloor basalts collected by drilling ( kato et al . , 2009b ) .
these facts suggest that upwelling hydrothermal fluids are gradually mixed and cooled in the shallow sub - seafloor environments pervaded with the penetrating seawater and then iron and sulfide in the fluids are precipitated as pyrite .
depending on the end - member concentrations of fe and h2s , the sub - seafloor mixing , and subsequent pyrite precipitation may result in the presence of high fe / h2s low - temperature fluids .
however , so far we have not determined the end - member concentrations of iron and sulfide because of lack of high temperature vent fluids in the snail site .
further investigations are needed to assess the model of the generation of the fe - type fluids .
it is remarkable that ammonia - oxidation yields the highest bioavailable energy for the borehole fluid in the snail site followed by iron - oxidation ( figure 5b ) , although the bioavailable energy yields for the borehole fluid in the pika site could not be calculated due to incomplete geochemical data ( table a1 in appendix ) .
archaea accounted for 2758% of the total cell number in the borehole fluids ( kato et al .
, 2009b ) , and putative ammonia - oxidizers , such as mgi and psl12-related group , were detected in the borehole fluids ( table 2 ) .
this may be comparable to or higher than the result that zetaproteobacteria accounted for 632% in the borehole fluids ( kato et al .
, 2009b ) and is consistent with the thermodynamic calculation results : considerable numbers of putative ammonia - oxidizers as well as putative iron - oxidizers are expected to be present in the borehole fluids .
considering the inferred metabolic functions of the abundant phylotypes in each library from the samples as described above ( tables 1 and 2 ) , it seems that the microbial community structures observed in the smt hydrothermal fields are constrained by the energy availability of the fluids .
we propose a model for the appearance of the microbial community structures in the smt based on the results of microbiological , geochemical , and thermodynamic analyses ( figure 6 ) .
although this model is mainly based on the results from the snail site , our results from the pika and archaean sites can partially fit this model ( e.g. , the detection of putative sulfide - oxidizers in the active sulfide structures in the pika and archaean sites and that of putative iron- and ammonia - oxidizers in the borehole fluids in pika site ) . a model for the appearance of the microbial community structures in each habitat in the smt .
upwelling high temperature hydrothermal fluids discharged from vents rapidly react with seawater , and lead to the precipitation of metal sulfides , which results in the formation of the chimney- or mound - like structures on the seafloor .
sequentially , hydrothermal fluids are mixed with seawater within the wall of the sulfide structures , which leads to the occurrence of steep chemical disequilibria . in such environments , hydrogen , and sulfide - oxidation reactions
yield high bioavailable energy , and accordingly hydrogen - oxidizers and sulfide - oxidizers may be relatively abundant in the microbial communities .
in contrast , a portion of the upwelling hydrothermal fluids can permeate into porous basaltic pillow lava .
the hydrothermal fluids may be gradually mixed and cooled in the shallow sub - seafloor environments pervaded with the penetrating seawater and then iron and sulfide in the fluids may be precipitated as pyrite .
this sub - seafloor process would generate fe - type fluids . in the fe - type fluids , iron - oxidation yields high bioavailable energy , and accordingly
, iron - oxidizers can dominate in the microbial communities as observed in the borehole fluids and iron - rich mats .
in this paper , we summarized the microbial community structures in various habitats in the smt .
these findings highlight the uniqueness of the microbial communities in each habitat . on the whole , the results of thermodynamic calculations using the actual geochemical data are consistent with the presence / absence of each chemolithoautotroph in the microbial communities .
the high bioavailable energy yield of iron - oxidation in the borehole and several vent fluids may be related to the appearance of microbial communities with abundant zetaproteobacteria ( putative iron - oxidizing chemolithoautotrophs ) , i.e. , the iron - based ecosystem , in such environments . based on the microbiological geochemical thermodynamic results , a model for the appearance of the microbial community structures in the smt is proposed .
it should be noted that the molecular microbiological methods we used mainly targeted dna extracted from environmental samples and have some shortcomings ( wintzingerode et al . , 1997 ) .
firstly , we can not determine whether the detected phylotypes are active in the environments or not . rna - based analysis ( such as reverse transcript pcr and fish ) can identify active members thriving in environments .
secondly , the physiologies of the phylotypes can not be directly determined from the phylogeny .
we believe that the diverse phylotypes in the zetaproteobacteria include iron - oxidizing chemolithoautotrophs , although this must be verified by culture - dependent analyses . as shown here , the thermodynamic modeling by simple mixing of hydrothermal fluids with seawater is a powerful tool for predicting the microbial community structures in active chimneys where the mixing of hydrothermal fluids with seawater occurs immediately ( takai and nakamura , 2010 ; amend et al . , 2011 ) .
further careful calculations accompanied by other factors such as mineral precipitation will provide more helpful information for understanding the mechanisms shaping the microbial community structures in global deep - sea hydrothermal systems .
the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest . | ### Summary:
: microbial community structures in deep - sea hydrothermal vents fields are constrained by available energy yields provided by inorganic redox reactions , which are in turn controlled by chemical composition of hydrothermal fluids . in the past two decades ,
geochemical and microbiological studies have been conducted in deep - sea hydrothermal vents at three geographically different areas of the southern mariana trough ( smt ) . a variety of geochemical data of hydrothermal fluids and an unparalleled microbiological dataset of various samples ( i.e. , sulfide structures of active vents , iron - rich mats , borehole fluids , and ambient seawater ) are available for comparative analyses . here
, we summarize the geochemical and microbiological characteristics in the smt and assess the relationship between the microbial community structures and the fluid geochemistry in the smt by thermodynamic modeling . in the high temperature vent fluids , aerobic sulfide - oxidation has the potential to yield large amounts of bioavailable energy in the vent fluids , which is consistent with the detection of species related to sulfide - oxidizing bacteria ( such as thiomicrospira in the gammaproteobacteria and sulfurimonas in the epsilonproteobacteria ) .
conversely , the bioavailable energy yield from aerobic iron - oxidation reactions in the low - temperature fluids collected from man - made boreholes and several natural vents were comparable to or higher than those from sulfide - oxidation .
this is also consistent with the detection of species related to iron - oxidizing bacteria ( mariprofundus in the zetaproteobacteria ) in such low - temperature samples .
the results of combination of microbiological , geochemical , and thermodynamic analyses in the smt provide novel insights into the presence and significance of iron - based microbial ecosystems in deep - sea hydrothermal fields . |
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: variable medical involvement in application design limits assessment of accuracy before purchase limitations of image interpretation using smartphones are a drawback of dicom viewing applications further work on the accuracy of primary diagnosis using these dicom viewing applications is needed
smartphone applications are software applications that can be downloaded onto smartphones . smartphone health - related applications are rapidly increasingly in number , with approximately 1,000 new applications released each month and 142 million annual downloads predicted by 2016 .
their use is popular , with 85 % of medical professionals using smartphones and 30 - 50 % reporting use of applications within their clinical practice [ 2 , 3 ] .
the range of smartphone applications available has been reported in various specialties , including orthopaedics , colorectal surgery , anaesthesia / pain medicine [ 6 , 7 ] , and microbiology .
however concerns regarding the lack of medical involvement in application design [ 5 , 7 , 8 ] and the reliability of application content [ 9 , 10 ] have been raised .
the potential utility of smartphone applications in radiology , such as portable doppler ultrasound and mobile reporting of coronary computed tomography angiography [ 11 , 12 ] , have recently been reported ; however , there is a general paucity of information within the literature regarding radiology - related applications
. the royal college of radiologists of the uk ( rcr ) has recently launched irefer , an evidence - based and peer - reviewed radiological investigation guideline tool .
however the degree of medical involvement in the development of other radiology - related applications is currently unclear .
one of the most anticipated prospects in radiology is the development of smartphone applications that permit the mobile viewing of digital imaging and communications in medicine ( dicom ) format images .
this has the potential to allow remote reviewing of images , leading to potentially more timely diagnosis .
however , the limitations of smartphone displays on primary diagnosis and the deleterious effects of other factors such as ambient light and network properties must be considered . in view of this and
given the popularity of smartphone applications in healthcare , we aimed to identify contemporary radiology - related smartphone applications , including teaching , reference and dicom viewing applications , and assess the level of advertised medical involvement in application development .
six major application stores ( apple , google play , blackberry mobile market , nokia ovi , samsung and microsoft windows marketplace ) were searched for smartphone applications specifically targeted to radiology using the terms radiology , radiation , x - ray(s ) , computed tomography / ct , magnetic resonance imaging / mri , ultrasound , nuclear medicine , fluoroscopy , mammography and mammogram .
radiotherapy , veterinary and dental radiology applications as well as non - english language applications , games , wallpaper and applications under construction were excluded .
data was recorded on the source of the application , application name , ratings , number of ratings and cost [ prices in us dollars and british pounds were converted to euros using the exchange rate on 31 april 2013 ( $ 1 = 0.7779 , 1 = 1.1853 ) ] .
details regarding application content and medical input were obtained from the associated application description and any relevant websites .
applications were categorised as teaching ( flashcards , questions , revision guides / notes , textbooks , cases , tutorials / talks , etc . ) , reference ( guidelines , cancer staging , radiology positioning guides , scanning protocols , glossaries , calculators including radiation dose calculators , convertors , cost comparison , etc . ) , viewing software , hospital information system ( his ) ( patient data including imaging reports ) , patient education and others ( marketing , magazines , journal access , etc . ) .
food and drug administration ( fda ) approval for viewing software applications was ascertained from application - related publicity material and the fda 510(k ) premarket notification database .
three hundred twenty - one applications were identified ( see table 1 for a selection of example applications ) .
the majority of these were available from either the apple and google play application stores [ 172 ( 54 % ) and 108 ( 34 % ) respectively ] .
six ( 2 % ) were from the blackberry mobile market and only 1 application was identified in each of the nokia and windows stores , while no relevant applications were found in the samsung store .
twenty - one applications ( 7 % ) were available from both apple and google play , ten ( 3 % ) from apple , google play and blackberry , and two from google play and blackberry stores.table 1examples of radiology - related smartphone applications .
pacs = picture archiving and communication systemapplication categoryexamplebrief descriptionteachingimaios e - anatomyatlas of anatomy based on computed tomography and magnetic resonance images .
users can scroll , zoom and rotate images , as well as toggle labels on and offradiopaediaradiology cases for health professionals , with emphasis on radiology trainees .
scrollable multi - image stacks , quiz questions and answers with links to related articlesreferencevirtual radiographerguide to radiographic positioning , with sample radiographs , radiographic calculator and examples of common radiographic pathologylung tnm calclung cancer staging calculator based on the 7 edition of the lung cancer tnm classification ( 2010)ireferradiological investigation guidelines tool from the royal college of radiologists based on the 7 edition of making the best use of clinical radiology services .
helps referring general practitioners , physicians and other health professionals determine the most appropriate imaging investigationviewerefilm mobileallows remote access to efilm workstations / pacs , permitting the user to view lists of studies , forward studies to other efilm devices , and view images on and download studies to a smartphone . not for diagnostic usepatient educationchild
mri prephelps parents and medical personnel prepare children for mri using pictures , sounds and child - friendly languagehisubikareallows physicians to remotely access patient health records and test results , including radiology , as well as view patient appointmentsotherrsnaofficial app of the radiological society of north america allowing access to mobile versions of radiographics , radiology and radiologyinfo .
pacs = picture archiving and communication system table 2 displays a breakdown of application categories found on each source platform .
teaching was the most common category [ 158 ( 49 % ) ] .
teaching topics included patient cases ( 54 ) , textbooks or encyclopaedias ( 40 ) , exam revision aids ( 36 ) and radiological anatomy ( 30 ) .
reference was the second most popular type ( 96 [ 30 % ] ) , followed by viewing software ( 29 [ 9 % ] ) .
applications.table 2number of radiology - related smartphone applications by category available from the different application stores .
his = hospital information systemapplication storeteachingreferenceviewing softwarepatient educationhisothertotalapple9147181213172google play523551312108blackberry3100026nokia0000011windows0100001samsung0000000apple / google play67600221apple / blackberry / google play63000110blackberry / google play0200002total15896292531321table 3summary of the available viewing software smartphone applications .
* price refers to the advertised cost of downloading the application from the application store ; additional costs are not included .
mip = maximum intensity projection , mpr = multiplanar reformatting , pacs = picture archiving and communication system , roi = region of interest , suv = specific uptake value , vrt = volume - rendering technique , w / l = window levelapplication nameapplication storedeveloperprice*fda approvedadvertised viewing featurespacsadvertised limitationstablet application availablecentricity radiology mobile accessapple/ google playge healthcarefreenozoom , pan , scroll , w / l , 2d , 3d , mip , mprge centricity pacsnot for diagnostic useyesdicomdroidgoogle playmediko srl20.62nonot statedany pacsnone statedyesdocbookmdgoogle playdocbookmdfreenonot statedany pacs via messaging applicationnone statedyesdoshi diagapplemy personal health record expressfreenozoom , scroll , cine loopdoshi diagnostics pacsnot for diagnostic usenoefilm mobileapplemerge healthcarefreenozoom , pan , w / lefilm pacsnot for diagnostic useyesendeavorgoogle playcomputer vision research groupfreenozoom , pan , scroll , w / l , annotateany pacsnone statedyesfujifilm synapse mobilityapple/ google playfujifilm medical systems usafreeyes ( for iphone/ ipad)zoom , w / l , 2d , 3d , mip , mprfujifilm systems pacsfor diagnostic use on iphone / ipadyesiclarity lite : advanced medical imaging viewer and image management toolappleicrco inc.freenozoom , pan , scroll , w / l , measurement , cine loopany pacsnot for diagnostic useyesiclarity : advanced medical imaging viewer and image management toolappleicrco inc.3.54nozoom , pan , scroll , w / l , measure , cine loopany pacsnot for diagnostic useyesindependentapplemy personal health record expressfreenozoom , scroll , cine loopindependent imaging s pacsnot for diagnostic useyesinfinitt mobile viewerapple/ google playinfinitt healthcarefreenozoom , pan , w / l , cine , measure , roiinfinitt pacsnot for diagnostic useyesintelegridappleintelemagefreenozoom , pan , scroll , w / lany pacsnone statedyesiop mobileapplezed technologiesfreenonot statedolympic park pacsnone statedyesipaxeraapplepaxeramed corp3.54nozoom , pan , rotate , w / l , measureany pacsnot for diagnostic useyesmitk pocketapplemedical embedded systemsfreenozoom , mpr , w / l , measure , annotationany pacsnone statedyesmobile mimapplemim softwarefreeyes2d , 3d , mip , measure , annotate , suvany pacsonly to be used when no access to workstations . not for mammographyyesmphrxapplemy
personal healthfreenozoom , scroll , cine loopany pacs via mphrx cloud systemnot for diagnostic usenomrdsgoogle playinrete srlfreenonot statedany pacsnone statedyesosirix hdapplepixmeo sarl24.88nozoom , pan , rotate , w / l , cine , measure , roiany pacsnot for diagnostic useyesresolutionmd mobileapple/ google playcalgary scientificfreeyes ( for iphone/ ipad)zoom , pan , w / l , 2d , 3d , mip , mpr , measure , cineresolutionmd pacsfor diagnostic use on iphone / ipad .
agfreenonot statedany pacsnot for diagnostic useseemyradiology mobileappleneurostar solutionsfreenozoom , w / lany pacsnot for diagnostic useyesshields mriapple/ google playshields mrifreenonot statedshields healthcare group pacsnone statedyessiemens syngo . via webreportapplesiemensfreeno2d ,
3d , mip , mprsiemens syngo pacsnot for diagnostic useyessiemens syngo.via webviewerapplesiemensfreeno2d , 3d , mip , mpr , vrtsiemens syngo pacsnot for diagnostic useyessiui pie-3appleshantou institute of ultrasonic inst co. ltd.82.96nozoom , cine playbacksiui ultrasound pacsnone statedyesvizuaapplevizuafreeno2d , 3d , annotateany pacs via vizua cloud systemnone statedyesvuemeapplemim softwarefreenow / l , 3d , mipany pacsnot for diagnostic useyesxr - express for mobile devicesappple/ google playnew mexico softwarefreenozoomxr - express pacsnone statedyes number of radiology - related smartphone applications by category available from the different application stores .
* price refers to the advertised cost of downloading the application from the application store ; additional costs are not included .
mip = maximum intensity projection , mpr = multiplanar reformatting , pacs = picture archiving and communication system , roi = region of interest , suv = specific uptake value , vrt = volume - rendering technique , w / l = window level one hundred sixteen applications ( 36 % ) had advertised medical professional involvement in application development .
seventy - six ( 24 % ) of these stated specific named medical professional involvement ( named doctor , radiographer , medical physicist or hospital ) in the publicity information whilst a further 40 ( 12 % ) mentioned unnamed medical professional involvement ( such as radiologist or emergency physician ) .
twelve ( 4 % ) acknowledged guidelines or papers used in developing the application , 12 ( 4 % ) were designed by radiology or medical societies , such as the rcr or the american college of radiology ( acr ) , and 37 ( 12 % ) were developed by imaging companies ( such as siemens or general electric ) .
two reported involvement of a named person but did not disclose their professional background , while six ( 2 % ) stated general terms such as exam experts ; 136 ( 42 % ) applications did not disclose authorship .
one hundred thrity - five applications were free to download , 4 provided free limited access to a paid application and 182 charged for access .
the mean price of the paid applications was 11.65 , ranging from 0.82 to 82.97 .
of the paid applications , viewing software applications were the most expensive , costing on average 27.11 to download , followed by teaching
the mean rating of the 124 rated applications was 3.18 out of 5 . only 38 ( 12 % ) applications had 10 or more ratings , and 10 ( 3 % ) had more than 50 ratings .
paid applications rated significantly higher than free applications ( 3.65 versus 3.11 , p < 0.0001 respectively ) , as did those with medical input in design compared with no stated medical input ( 3.26 versus 3.07 , p < 0.05 respectively ) .
teaching was the most common category [ 158 ( 49 % ) ] .
teaching topics included patient cases ( 54 ) , textbooks or encyclopaedias ( 40 ) , exam revision aids ( 36 ) and radiological anatomy ( 30 ) .
reference was the second most popular type ( 96 [ 30 % ] ) , followed by viewing software ( 29 [ 9 % ] ) .
applications.table 2number of radiology - related smartphone applications by category available from the different application stores .
his = hospital information systemapplication storeteachingreferenceviewing softwarepatient educationhisothertotalapple9147181213172google play523551312108blackberry3100026nokia0000011windows0100001samsung0000000apple / google play67600221apple / blackberry / google play63000110blackberry / google play0200002total15896292531321table 3summary of the available viewing software
* price refers to the advertised cost of downloading the application from the application store ; additional costs are not included .
mip = maximum intensity projection , mpr = multiplanar reformatting , pacs = picture archiving and communication system , roi = region of interest , suv = specific uptake value , vrt = volume - rendering technique , w / l = window levelapplication nameapplication storedeveloperprice*fda approvedadvertised viewing featurespacsadvertised limitationstablet application availablecentricity radiology mobile accessapple/ google playge healthcarefreenozoom , pan , scroll , w / l , 2d , 3d , mip , mprge centricity pacsnot for diagnostic useyesdicomdroidgoogle playmediko srl20.62nonot statedany pacsnone statedyesdocbookmdgoogle playdocbookmdfreenonot statedany pacs via messaging applicationnone statedyesdoshi diagapplemy personal health record expressfreenozoom , scroll , cine loopdoshi diagnostics pacsnot for diagnostic usenoefilm mobileapplemerge healthcarefreenozoom , pan , w / lefilm pacsnot for diagnostic useyesendeavorgoogle playcomputer vision research groupfreenozoom , pan , scroll , w / l , annotateany pacsnone statedyesfujifilm synapse mobilityapple/ google playfujifilm medical systems usafreeyes ( for iphone/ ipad)zoom , w / l , 2d , 3d , mip , mprfujifilm systems pacsfor diagnostic use on iphone / ipadyesiclarity lite : advanced medical imaging viewer and image management toolappleicrco inc.freenozoom , pan , scroll , w / l , measurement , cine loopany pacsnot for diagnostic useyesiclarity : advanced medical imaging viewer and image management toolappleicrco inc.3.54nozoom , pan , scroll , w / l , measure , cine loopany pacsnot for diagnostic useyesindependentapplemy personal health record expressfreenozoom , scroll , cine loopindependent imaging s pacsnot for diagnostic useyesinfinitt mobile viewerapple/ google playinfinitt healthcarefreenozoom , pan , w / l , cine , measure , roiinfinitt pacsnot for diagnostic useyesintelegridappleintelemagefreenozoom , pan , scroll , w / lany pacsnone statedyesiop mobileapplezed technologiesfreenonot statedolympic park pacsnone statedyesipaxeraapplepaxeramed corp3.54nozoom , pan , rotate , w / l , measureany pacsnot for diagnostic useyesmitk pocketapplemedical embedded systemsfreenozoom , mpr , w / l , measure , annotationany pacsnone statedyesmobile mimapplemim softwarefreeyes2d , 3d , mip , measure , annotate , suvany pacsonly to be used when no access to workstations . not for mammographyyesmphrxapplemy
personal healthfreenozoom , scroll , cine loopany pacs via mphrx cloud systemnot for diagnostic usenomrdsgoogle playinrete srlfreenonot statedany pacsnone statedyesosirix hdapplepixmeo sarl24.88nozoom , pan , rotate , w / l , cine , measure , roiany pacsnot for diagnostic useyesresolutionmd mobileapple/ google playcalgary scientificfreeyes ( for iphone/ ipad)zoom , pan , w / l , 2d , 3d , mip , mpr , measure , cineresolutionmd pacsfor diagnostic use on iphone / ipad . not for mammographyyessap electronic medical recordgoogle playsap
agfreenonot statedany pacsnot for diagnostic useseemyradiology mobileappleneurostar solutionsfreenozoom , w / lany pacsnot for diagnostic useyesshields mriapple/ google playshields mrifreenonot statedshields healthcare group pacsnone statedyessiemens syngo . via webreportapplesiemensfreeno2d , 3d , mip , mprsiemens syngo pacsnot for diagnostic useyessiemens syngo.via webviewerapplesiemensfreeno2d , 3d , mip , mpr , vrtsiemens syngo pacsnot for diagnostic useyessiui pie-3appleshantou institute of ultrasonic inst co. ltd.82.96nozoom , cine playbacksiui ultrasound pacsnone statedyesvizuaapplevizuafreeno2d , 3d , annotateany pacs via vizua cloud systemnone statedyesvuemeapplemim
softwarefreenow / l , 3d , mipany pacsnot for diagnostic useyesxr - express for mobile devicesappple/ google playnew mexico softwarefreenozoomxr - express pacsnone statedyes number of radiology - related smartphone applications by category available from the different application stores .
his = hospital information system summary of the available viewing software smartphone applications .
* price refers to the advertised cost of downloading the application from the application store ; additional costs are not included .
mip = maximum intensity projection , mpr = multiplanar reformatting , pacs = picture archiving and communication system , roi = region of interest , suv = specific uptake value , vrt = volume - rendering technique , w / l = window level
one hundred sixteen applications ( 36 % ) had advertised medical professional involvement in application development .
seventy - six ( 24 % ) of these stated specific named medical professional involvement ( named doctor , radiographer , medical physicist or hospital ) in the publicity information whilst a further 40 ( 12 % ) mentioned unnamed medical professional involvement ( such as radiologist or emergency physician ) .
twelve ( 4 % ) acknowledged guidelines or papers used in developing the application , 12 ( 4 % ) were designed by radiology or medical societies , such as the rcr or the american college of radiology ( acr ) , and 37 ( 12 % ) were developed by imaging companies ( such as siemens or general electric ) .
two reported involvement of a named person but did not disclose their professional background , while six ( 2 % ) stated general terms such as exam experts ; 136 ( 42 % ) applications did not disclose authorship .
one hundred thrity - five applications were free to download , 4 provided free limited access to a paid application and 182 charged for access .
the mean price of the paid applications was 11.65 , ranging from 0.82 to 82.97 .
of the paid applications , viewing software applications were the most expensive , costing on average 27.11 to download , followed by
only 38 ( 12 % ) applications had 10 or more ratings , and 10 ( 3 % ) had more than 50 ratings . paid applications rated significantly higher than free applications ( 3.65 versus 3.11 , p < 0.0001 respectively ) , as did those with medical input in design compared with no stated medical input ( 3.26 versus 3.07 , p < 0.05 respectively ) .
smartphones and their applications are increasingly used by medical practitioners and have potentially significant roles in the healthcare and clinical setting .
health - related applications in various medical fields have been studied ; however this is one of the first papers to review smartphone applications relevant to radiology .
. recently published a similar study assessing the range and benefits of radiology - related smartphone and tablet applications .
however their search only revealed 81 applications compared with the 321 identified in this study . whilst the dates of the search and the exclusion criteria used differed between the studies , the search performed by szekely et al .
compared with the previous reports in other specialties , a relatively large number of radiology - related applications were identified .
this probably reflects the general relevance of radiology compared with the previously studied medical fields , as well the rapid growth in medical applications .
the advent of smartphones and applications has made it easier for programmers , medically trained or not , to develop and publish medical - related literature .
this increased accessibility has obvious benefits ; however there are concerns regarding the accuracy of medical application content [ 5 , 710 ] . in keeping with this ,
only 44 % of applications in the study acknowledged medical professional / society involvement or the use of guidelines or papers in application development .
it is currently difficult for a potential user to determine the accuracy of application content prior to purchase .
the application stores provide a short description written by the application developer , customer ratings and comments , and a selection of screen shots . whilst the customer ratings provide a source of feedback , 61 % of applications in this study had no rating .
furthermore 69 % of those rated were based on less than ten ratings , reducing the reliability of the customer feedback .
this input should be clearly stated in the application advertising material to allow potential users to make an informed assessment of an application s reliability prior to purchase .
the fda plans to regulate a subset of smartphone medical applications that might present a potential risk to patients , such as those allowing display of medical images directly from a picture archiving and communication system ( pacs ) server ; however most of the applications identified in this study are not part of this subset .
another way of helping users gauge an application s reliability would be to develop a quality
this might be a role for the rcr or other radiology societies who could give their stamp of approval for products judged fit for the purpose . with an appropriate application it is possible to access dicom format images stored in pacs systems via a smartphone connected to the internet .
fifteen out of the 29 viewing software applications have the facility to allow images from any pacs to be viewed remotely , and the remaining 14 permit access to a named pacs server .
the viewing features available on these applications are becoming increasingly sophisticated , with many permitting multiplanar reformatting , two- or three - dimensional reconstructions , measuring as well as scrolling , panning , zooming and windowing .
the fda has released guidance on its intention to regulate a subset of medical applications , including those allowing access to dicom format images , however this guidance is currently only a recommendation as full regulatory oversight has not commenced .
three of the viewing software applications in the study had fda approval for primary diagnostic use ( table 3 ) .
the remaining 26 viewing software applications without fda approval should not be used for primary diagnosis ; however this was only stated in the publicity information of 62 % of these . to gain fda approval
the application must be shown to have substantial equivalence to another legally marketed device ( i.e. any new technological changes are at least as safe and effective as the predicate ) . whilst the software of the mobile pacs applications is very similar or identical to existing pacs systems ,
the relevant hardware is clearly different ( smartphones versus reporting workstation ) , and this potentially affects the safety of the smartphone application . with these hardware limitations in mind
both the mobile mim and resolutionmd applications have clear disclaimers stating they should only be used when there is no access to a workstation , as they are not intended to replace full workstations .
the medical devices directive ( mdd ) ensures safety and performance of medical devices throughout the eu , with each member state having its own regulatory framework .
however there is currently no consensus between member states over the definition of a medical device and which medical applications should be considered medical devices , leading to uncertainty among application developers and healthcare providers . in the uk , dicom viewing applications
would be considered a medical device by the medicines and healthcare products regulatory agency ( mhra ) .
every registered medical device in the eu must carry the ce ( conformit europene ) mark , signalling that the manufacturer is satisfied the product conforms to the relevant requirements in the relevant legislation .
most applications , including dicom viewing applications , are within the lowest risk category ( class i ) , which means the developers can self - declare conformity to the essential requirements without the need for independent review .
unfortunately there is currently very limited use of the ce mark in the application stores .
the ability to view full - resolution images remotely has implications for timely diagnosis and treatment ; however the limitations of using smartphones for image interpretation must be considered .
first , there are few studies investigating the diagnostic accuracy of image interpretation using smartphones [ 12 , 2023 ] .
second , smartphones can not meet the minimum standards for primary diagnostic displays required in europe .
for example , the rcr requires a screen resolution of 1,280 1,024 pixels and screen size of 42 cm , with the possibility of comparing serial examinations side by side ; the iphone 5 s display for example has 1,136 640 pixels and a 10.2-cm screen .
the deleterious effects of ambient light on mobile image interpretation also need to be taken into account . finally , reporting workstation displays undergo rigorous regular calibration and quality assurance procedures to ensure they remain fit for the purpose .
smartphones being used for primary diagnosis would have to be part of similar quality assurance programmes . therefore , despite fda approval , caution must be used when using dicom viewing applications for primary diagnosis on smartphones and we feel the fundamental limitations of smartphone displays means smartphones are more suited for reviewing images .
whilst radiologists are likely to appreciate such restrictions , other medical practitioners using these applications may be less aware of their limitations .
studies assessing tablet devices in this regard are promising [ 2628 ] ; however further research is required to determine their diagnostic accuracy .
data confidentiality is a major concern when using smartphones to review patient images , particularly if the phone is lost or stolen .
one option used by several of the viewing applications is not storing any protected health information on the mobile device .
instead the user has to log in to a secure server and access the data via a secure , encrypted data transfer link .
further improvements in data security can be gained from applications utilising the htlm5 markup language .
in contrast to previous versions , htlm5 has many commonly used applications integrated , such as video and audio elements .
this makes it easier for users to access graphical and multimedia content directly via the web server without the need for additional plug - ins and subsequent data download onto a user s device . whilst these options provide safe methods for managing confidential data
, it obviously limits the use of the application to areas that have internet access .
data stored in this way should be encrypted , and there should be the possibility to remotely disable lost or stolen devices .
employees , including healthcare workers , are increasingly using their own smartphones for work , resulting in a
a recent survey showed that 41 % of us healthcare workers do not have a password on their phone , over 50 % access unsecure wi - fi networks and 48 % have not disabled the bluetooth discoverable mode . furthermore many healthcare institutions do not have a formal mobile strategy , with
most unable to wipe the data from an employee s personal device should it be lost or stolen .
such practices raise serious security issues , which , in the setting of the healthcare system , could place patients protected health information at risk .
the speed of data transfer and download is a further limitation of mobile image review on smartphones .
a study evaluating the osirix smartphone application showed that the time taken to transfer 85 5-mm axial slices of a ct of the abdomen and pelvis using an iphone 3s was up to 51 s with a wifi connection , over 7 min using a 3 g connection and over 35 min using an edge network connection .
the time taken for transferring thin ( 1-mm ) slices to permit multiplanar formatting will be considerably longer . while smartphone and network technology continues to improve , with a corresponding increase in the rate of data transfer , the prolonged transfer times , particularly when no wi - fi connection is available , may currently limit the usefulness of smartphone viewing software applications .
other concerns regarding noise , distraction , infection control , and health and safety cautions have also been reported [ 30 , 31 ] .
some applications charge a one - off fee , which allows the user to download and use the application .
in contrast , several applications are free to download but require access to a named pacs system or specific additional hardware or software to work .
the use of such applications is restricted to practitioners whose institutions have access to the required pacs system , negating some , if not all , of these hidden fees , but restricting their wider usage .
one of the limitations of the study was the use of named medical involvement as a surrogate marker for reliability of application content .
as the cost of downloading and reviewing all of the applications identified was prohibitively expensive , the validity and accuracy of the content within applications could not be directly verified .
the most common applications are teaching and reference based , for which quality of information is crucial ; however many of these do not appear to have medical input in their development .
additional measures , such as a quality kite mark , are advised to ensure accuracy of such application content and better inform users prior to purchase .
smartphone applications can also permit mobile interpretation of dicom format images ; however the limitations of smartphone displays and the need for optimal viewing conditions must be emphasised , especially if they are potentially used for primary interpretation .
richard brady is owner of researchactive.com , a company that develops medical applications and provides mhealth solutions . | ### Summary:
: objectivesmedical smartphone applications are increasingly popular amongst doctors . however , the quality of their content is variable . we assessed contemporary radiology - related smartphone applications , focussing on the level of advertised medical involvement in application development.methodssix
major application stores were searched between 18 - 30 june 2012 using the terms radiology , radiation , x - ray(s ) , computed tomography / ct , magnetic resonance imaging / mri , ultrasound , nuclear medicine , fluoroscopy and mammography / mammogram .
application ratings , cost and medical input in development were recorded.results321 applications were identified .
one hundred fifty - eight were " teaching " and 96 reference .
three of the 29 dicom viewing applications had fda approval for primary diagnosis , while 62 % stated they should not be used for primary diagnosis ; 24 % of applications stated named medical professional involvement , 12 % had unnamed medical involvement and 4 % acknowledged guidelines or papers ; 42 % did not disclose authorship.conclusionsa large variety of radiology - related smartphone applications are available with many potential benefits .
advertised medical involvement in application design is variable , making assessment of their accuracy difficult prior to purchase .
additional measures are required to ensure the accuracy of such applications .
the limitations of image interpretation using smartphones are a major drawback of dicom viewing applications .
further research into the accuracy of primary diagnosis using such applications is needed.main messages a large variety of radiology smartphone applications are available with many potential benefits variable medical involvement in application design limits assessment of accuracy before purchase limitations of image interpretation using smartphones are a drawback of dicom viewing applications further work on the accuracy of primary diagnosis using these dicom viewing applications is needed |
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: dry eye disease ( ded ) is multifactorial and can be caused by poor quality tear film and inflammation of the eyelid / ocular surface resulting from a lower tear production rate and/or a tear instability . in ded , the ocular surface becomes dry and lacks lubrication , eventually leading to ocular surface damage .
infrared ( ir ) ocular thermography determines ocular surface temperature ( ost ) of the eye and preorbital skin by measuring the amount of ir radiation emitted from the surface with an infrared thermal imaging camera .
measurements are then processed into a color coded display image ( thermogram ) for interpretation and analysis .
noninvasive ocular thermography was first introduced in 1968 and was used to evaluate both normal and pathological conditions [ 47 ] . capturing ost changes using ir ocular thermography reflects the nature of the tear film and its stability [ 810 ] and has been used to study ded since 1993 .
morgan and his associates investigated the temperature difference between limbus and central cornea ( termed as rtd , radial temperature difference ) on a 66-year - old chronic dry eye patient and reported a significant difference in rtd between dry eye ( 1.40c ) and healthy eye ( 0.37c ) .
further studies on dry eye have been performed using ocular thermometry / thermography since then [ 3 , 8 , 1122 ] and the findings are summarised in table 1 .
most of the reported studies only considered static measures ( i.e. , study of ost on a single frame ) or temporal / dynamic measures ( i.e. , study of ost changes over time ) .
the ost indices studied were limited and did not document the whole exposed ocular surface .
software used and method employed to precisely define anatomical locations across the ocular surface have also varied ( table 1 ) .
our study was designed to investigate the ocular surface temperature in dry eye using both static and dynamic measures .
a novel diamond method in marking the ocular surface and ost acquisition was employed and ten ost indices were included to document the whole inferior zone of the exposed ocular surface .
the research protocol was approved by the singapore national health group ( nhg ) domain - specific review board ( dsrb ) and the singapore polytechnic ethics review committee and the work adhered to the tenets of the declaration of helsinki .
sixty - two dry eye ( 48 10 years ; 14 male and 48 female ) and 63 age- and sex - matched control subjects ( 46 7 years ; 16 male and 47 female ) completed the study .
the inclusion criteria for the dry eye subjects were as described previously : use of tear replacement therapy and having either a fluorescein tear break - up time of 10 seconds or less or a schirmer i test result of less than 10 mm in 5 min along with presence of corneal or conjunctiva staining .
all dry eye patients were screened and diagnosed by an ophthalmologist at khoo teck puat hospital eye clinic .
classification of mild or moderate and severe patients was based on a composite disease severity index , derived from the dry eye workshop severity scale .
control subjects were those not using tear replacement therapy or any topical medication and without signs or symptoms of dry eye .
all subjects were required to be noncontact lens wearers for at least two years prior to enrolment .
subjects were excluded from control group if they had schirmer i test result of less than 10 mm in 5 min or fluorescein tear break - up time of 10 seconds or less .
subjects with any anterior ocular anomalies ( e.g. , current ocular infection , allergy , or ptosis ) , those who had undergone surgery or are taking any medication that could affect the tear film , or those who were currently pregnant or breastfeeding were excluded .
subjects refrained from using their eye - drops or eye make - up on the day of measurement .
ocular thermography was performed in real time using an infrared thermotracer ( nec th9420 ) with resolution of 640 ( h ) 480 ( v ) pixels , operational sensitivity of 0.06c , and frequency of 30 frames per second , detecting infrared radiation between 8 and 14 m . the emissivity of 0.98 was assumed .
a standard examination protocol as reported in the literatures [ 8 , 10 , 11 , 17 ] was adopted .
all the measurements were performed from 9 am to 2 pm in the same room with controlled room temperature ( 24.06 0.41c ) and humidity ( 49.76 2.61% ) , with no air drifts and the same brightness ( 380 lux ) .
subjects were adapted to the room for 20 minutes prior to ocular thermography as previous work has shown that this period was necessary to achieve ocular temperature stabilisation .
as corneal temperature is strongly associated with body temperature and seemed to plateau at 36.5c to 37.0c , body temperature for all subjects was measured and subjects with body temperature 37c were excluded .
ost was recorded under the conditions described by morgan and associates : the subjects blinked normally , closed for 3 s , and the first image was recorded just after the eyes had opened [ 11 , 27 ] .
300 frames of real time thermal images reflecting ost changes at the ocular surface were captured over 10 s sustained eye opening .
the measurement was done three times on the right eye followed by the left eye . at any time
if subject blinked or changed fixation before 10 s , the measurement was discounted and repeated .
a novel diamond method was used to mark the ocular surface using a custom - designed ost analysis v2 software ( developed using matlab simulink 7.11.0 , r2010b ) .
the region of interest ( roi ) formed by five anatomical points across the ocular surface ( labelled as 15 ) was shaped like a diamond ( figure 1 ) .
this method has the advantages of ( 1 ) overcoming reported problems of truncated image by upper lids , ( 2 ) minimizing possible inconsistency in ost acquisition due to variation in palpebral aperture size , and ( 3 ) enabling study of the inferior zone of the ocular surface that was reported to be a predictive area in detection of dry eye subtypes .
each point marked represents an area of 3 3 pixels so that temperature was an average of nine pixels : temporal limbus ( lt).nasal limbus ( ln).extreme temporal conjunctiva ( t1).extreme nasal conjunctiva ( t4).most inferior point of the ocular surface.once the marking of roi was completed , ost acquisition and processing was performed automatically by double clicking the last point marked ( point 5 ) to activate the ost analysis v2 program and process all the 300 frames .
all frame marking and data processing were undertaken by a single examiner ( ll ) .
ten ost indices of the ocular surface were generated as shown in table 2 . in this study
, gcc denotes the temperature of the geometric center of the cornea , obtained midway between lt and ln .
the ost indices were selected to document the whole inferior zone of the exposed ocular surface within roi which had included most of the reported ost indices as shown in table 1 with few newly added indices .
all the ten ost indices extracted by the diamond method were shown to be highly repeatable in assessing healthy and dry eyes in terms of interimage , interexaminer , and intraexaminer variability .
static measures were the study of absolute ost at t = 0 s , 5 s , and 10 s after eye opening .
dynamic measures were the study of mean change ( relative to baseline ) as well as net change in ost over 10 s of sustained eye opening . to prevent difficulties arising when nonindependent data were collected from both eyes , only data obtained from right eye were used in the analysis .
one - way anova was performed for the ten indices studied to explore differences between dry eye and control subjects at t = 0 s , 5 s , and 10 s. for dynamic measures , a general linear model was constructed ( two - way repeated measures anova model ) to test the significance of each group , time , and their interaction ( group by time ) effects , where the interaction between groups over time was the key outcome . post hoc analysis for significance of the group effect at each time point was conducted using unpaired t - test ( two - tailed ) , on ost indices with significant outcomes .
we acknowledged that many disease severity criteria are confounded by complex disease subtypes and a lack of standardisation , and the selection of single criteria for assessment of disease severity is therefore fraught with difficulties [ 3133 ] .
both dry eye and control subjects showed positive compliance during ocular thermography measurements and therefore it was possible to record reliable data in all cases . there were no reports of reflex tearing and any discomfort from the subjects during the course of the study .
although eight seconds of sustained eye opening has been reported to be an easily achievable target for subjects without causing reflex tearing , other studies had reported to be equally achievable for subjects to hold for 10 s [ 14 , 17 ] .
for static measures , dry eye recorded a significantly lower temperature ( for gcc , most , min t , max t , t4 , ct , lt , and ln ) as compared to controls at 0 s , 5 s , and 10 s ( one - way anova , p < 0.05 ) .
the differences were highly significant ( p < 0.01 ) for gcc , most , max t , t4 , ct , and lt and were significant ( p < 0.05 ) for min t and ln .
there were marginal significant differences found for cn at 5 s and 10 s and no significant differences were found between the two groups for t1 ( figure 2 ) .
for dynamic measures , dry eye had significantly steeper regression line of mean change ( corresponding to greater net change ) only for two out of the ten ost indices : max t and t4 ( figure 3 ) .
two - way analysis of variance showed that there were significant group by time interaction effects for max t and t4 temperatures ( max t : f = 4.6814 , p = 0.0324 ; t4 : f = 5.9506 , p = 0.0161 ) .
for max t , the drop in mean change in dry eye was statistically significant from 5 s onward ( unpaired t - test , 5 s , p = 0.037 ; 6 s , p = 0.012 ; 7 s , p = 0.022 ; 8 s , p = 0.023 ; 9 s , p = 0.016 ; 10 s , p = 0.019 ) .
net change for max t in dry eye over 10 s was 0.17 0.17c , which was two times greater as compared to controls ( 0.09 0.21c ) .
cooling rate as indicated by gradient of the graph for max t was also twice as much as in dry eye ( 0.0164c / s ) as compared to controls ( 0.0072c / s ) ( figure 3 ) . for t4 ,
the drop in mean change has only happened in dry eye group and it was statistically significant from 3 s onward ( unpaired t - test , 3 s , p = 0.023 ; 4 s , p = 0.005 ; 5 s , p = 0.014 ; 6 s , p = 0.009 ; 7 s , p = 0.047 ; 8 s , p = 0.036 ; 9 s , p = 0.028 ; 10 s , p = 0.005 ) .
t4 for control group was pretty stable during the 10 s of sustained eye opening .
net change for t4 in dry eye over 10 s was 0.09 0.22c , which was more than two times greater as compared to controls ( 0.04 0.24c ) .
cooling rate for t4 was also more than two times greater in dry eye ( 0.0091c / s ) as compared to controls ( 0.0039c / s ) .
no significant differences were found in mean change at any point of time ( unpaired t - test at each 1 s interval , p > 0.05 ) between the two groups for other ost indices during dynamic measures ( figure 3 ) .
each ost index studied represented an area of 3 3 pixels , except for most . rather than report on individual pixel values which might be subject to local variation
we believe this is good compromise between single pixels and a larger roi which would provide less opportunity to analyse specific geographic areas of interest .
ost in dry eye was different from controls at different ocular surface areas during static measures upon eye opening ( t = 0 s ) as well as when t = 5 s and 10 s. as compared to controls , the ocular surface of dry eye subjects was significantly cooler as recorded at the geometric center of the cornea ( gcc ) as well as various areas at conjunctiva ( t4 , ct , and cn ) and limbus ( lt and ln ) and causing an overall lower mean ocular surface temperature ( most ) . as the ocular surface measured by the thermotracer consists of cornea - conjunctiva - limbal complex , it was not surprising to record a significantly lower minimum temperature of the ocular surface ( min t ) and maximum temperature of the ocular surface ( max t ) in dry eye . during dynamic measures ,
ost was found to drop over the 10 s of sustained eye opening in both the dry eye and control subjects .
only two ost indices ( out of ten ) had significant steeper regression line of mean change with greater net change in dry eye .
as for the temperature of the extreme nasal conjunctiva ( t4 ) , the change was only observed in dry eye subjects and was statistically significant from 3 s onward .
the primary source of ocular radiation measured by ocular thermography is the tear film so changes in tear film thickness and its composition alter the temperature measured .
lower ost in the dry eye group found in the current study could be due to a thinner tear film as a result of a thinner tear film lipid layer ( tfll ) in dry eye [ 34 , 35 ] .
tfll has been reported to be important in tear film stability and evaporation and is abnormal in dry eye [ 8 , 37 ] . according to the dry eye workshop report
, tear film instability is one of the two core mechanisms of dry eye and can lead to thickness variation and an overall thinner tear film .
the ocular surface was cooled by a thinner tear film leading to lower temperature recorded on various ocular surface areas ( geometric center of the cornea , conjunctiva and limbus ) during static measures at t = 0 s. ost was likely to be affected by variations in evaporation in the seconds after eye opening , in addition to the effects of convection .
not unexpectedly , lower temperatures were noted in dry eye subjects after 5 s and 10 s of eye opening .
thermography has been reported as an indirect method to evaluate tear evaporation rates and tear film impairment due to its ability to record subtle changes over the corneal temperature . indeed ,
tear evaporation in dry eye can cause a 10-fold reduction in tear thickness after a blink and was found to be correlated with lower corneal temperature and subjective discomfort symptoms .
this was apparent in the current report revealing a declining temperature on the various ocular surface areas from 0 s to 10 s during static measures .
the temperature gradient is varying at different ost indices and suggestive of different evaporation rate at different areas of the ocular surface .
lower ost can also be accounted for by the presence of cold receptors , a class of ion channels identified in nerve endings and in corneal and conjunctival epithelial cells that can mediate the pain transduction from the ocular surface .
although temperature variation has been reported to be higher in dry eyes when rtd ( radial temperature difference ) was studied by morgan et al .
[ 3 , 11 ] , rtd was not included in the current study as previous report has shown poor rtd repeatability when measured using the current thermotracer . a lower most value in dry eye was in agreement with the report by singh and bhinder [ 16 , 40 ] using remote sensor thermometry but conflicts with the report by morgan et al .
a warmer overall ocular surface has been accounted for by the increased conjunctival hyperaemia in dry eye [ 11 , 41 ] .
certainly , ost is increased during inflammatory disease [ 3 , 5 ] and ocular surface inflammation is a core mechanism in dry eye . a higher most could also be associated with higher blink rate in dry eye .
the conflicting results found in our study as compared to those previously reported may be due to various reasons .
firstly , most of our dry eye subjects did not present with conjunctival hyperaemia , the results were therefore different .
secondly , different experimental methodologies may lead to different findings as suggested by kamao et al . .
method in marking the ocular surface and ost acquisition in our study allowed a more holistic study on most as it covers a wider area of the ocular surface as compared to obtaining the most by averaging the temperature of the cornea and conjunctiva across the horizontal meridian in morgan et al .
furthermore , the roi studied was the lower half of the ocular surface whereby tear film will thin faster as compared to other areas due to evaporation and leads to a lower most in dry eye as shown in the current study .
ost measurements by singh and bhinder were made in a closed chamber instead of an open atmosphere so comparison with that work is clearly problematic as local environmental factors influence ost .
were mostly severe dry eye cases whereas the dry eye subjects in our study ranged from mild to moderate cases . in more severe cases ,
the level of local inflammation and greater conjunctiva hyperaemia may overwhelm evaporative effects , leading to a warmer ocular surface .
last but not least , age of subjects recruited could also cause different results . in previous projects , there was no apparent attempt to age - match the dry eye and the control groups .
this is important because ost was reported to decrease with age at a rate of 0.010c / year and the dry eye populations used by previous reports [ 11 , 14 , 17 , 18 ] were much older compared to the controls ; in other words , differences between the groups may be age - related rather than related to the disease itself . during dynamic measures ,
our results were in agreement with literatures that ocular surface cooled during sustained eye opening [ 12 , 45 ] and rate of the cooling was greater in the dry eye group .
, which postulates a mechanism by which local rupture of the tfll increases local tear evaporation rate leading to tear film rupture and tear film break - up .
tear film thinning and break - up have been shown to correspond to ocular surface cooling over time .
dry eye had a thinner tfll [ 34 , 35 ] and , upon eye opening , the tear film starts to thin due to evaporation leading to drop in temperature .
the tear film lipid could have depleted and no longer hold / protect the aqueous layer at t = 5 s ( for max t ) and at t = 3 s ( for t4 ) and hence a sudden increase in evaporation / tear film thinning and ocular surface cooling .
the cooling rate for max t was twice as much as in dry eye as compared to controls and may indirectly reflect the rate of evaporation in dry eyes as reported by li et al . .
a twofold and a threefold increase in the tear evaporation rate in dry eyes has been reported previously .
although tear evaporation was not measured in the current study , tear film cooling in dry eye upon eye opening as a result of tear evaporation as well as greater effect of the positive latent heat of tear vaporisation has also been reported [ 8 , 12 , 49 ] .
changes in t4 were only observed in dry eye subjects and could be easily differentiated from their controls ( figure 3 ) .
conjunctival temperature was reported to be higher than the central cornea [ 7 , 50 ] .
although the reasons remain unclear , temperature of the nasal conjunctiva was reported to be higher than that of the temporal conjunctiva because of the influence of greater blood flow due to more large vessels including the dorsal nasal artery and the angular artery at the nasal conjunctiva .
there are more large vessels , including the dorsal nasal artery and the angular artery , on the nasal side of the eye , and the medial rectus muscle has two anterior ciliary arteries , whereas the lateral rectus muscle has only one artery .
the difference in vascularisation at nasal and temporal conjunctiva could have created different tear film cooling rate in these two areas upon eye opening and therefore the different results found in t4 and t1 .
the reason why there was no change in t4 for the controls warranted further investigations . studying t4 at 3
s and onwards can be a potential diagnostic index for dry eye due to its
unique behaviour as compared to non - dry eye subjects . based on our findings
, 10 s of sustained eye opening may not be required as it is hard for dry eye patients to keep their eyes open for 10 s without inducing reflex tearing and blinking .
static and dynamic measurement of the ost provided two different aspects in studying the tear film .
both measurements were useful and can be used as clinical tool to assess dry eye . | ### Summary:
: purpose . to study ocular surface temperature ( ost ) in dry eyes by static and dynamic measures . methods .
ost was recorded on 62 dry eyes and 63 age- and sex - matched controls .
static measures were study of absolute ost at t = 0 , 5 , and 10 s after eye opening .
dynamic measures were study of mean change and net change in ost over 10 s of sustained eye opening .
ten ost indices studied were temperatures of the geometric center of the cornea ( gcc ) , extreme temporal ( t1 ) and nasal conjunctiva ( t4 ) , midtemporal ( ct ) and nasal conjunctiva ( cn ) , temporal ( lt ) and nasal ( ln ) limbus , and mean ( most ) , maximum ( max t ) , and minimum ( min t ) temperatures of the region of interest . results . for static measures , dry eyes recorded significantly lower gcc , most , min t , max t , t4 , ct , lt , ln , and cn . for dynamic measures ,
dry eyes had significantly steeper regression line of mean change ( corresponding to greater net change ) for max t 5 s onward and t4 at 3 s onward .
conclusions .
both static and dynamic measures of the ost were valuable and can be used as clinical tool to assess dry eye . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: metastatic non - small - cell lung cancer ( nsclc ) is an invariably lethal disease with poor prognosis and with a 5-year survival rate below 5%.1 the standard first - line therapy for advanced nsclc not characterized for epidermal growth factor receptor ( egfr ) or anaplastic lymphoma kinase ( alk ) translocation is represented by platinum - based combination therapy , which prolongs survival , controls symptoms , and improves quality of life versus best supportive care in patients with good performance status.2 first - line treatment with an egfr tyrosine kinase inhibitor ( tki ) , such as erlotinib hydrochloride ( tarceva ; hoffmann - la roche ltd , basel , switzerland ) , gefitinib ( iressa ; astrazeneca , london , uk ) or afatinib ( gilotrif ; boehringer ingelheim gmbh , ingelheim , germany ) , is recommended in patients harboring activating egfr mutations .
patients with alk rearrangements are candidates for a therapy with crizotinib ( xalkori ; pfizer , new york , ny , usa ) , a dual mesenchymal epithelial transition factor ( met ) and alk inhibitor .
unfortunately , irrespective of tumor biology and therapy , all patients inevitably develop resistance to any available therapy , with a median progression - free survival ( pfs ) of 6 months with platinum - based chemotherapy and 812 months for targeted therapies.2,3 few effective second - line treatment options are currently available , including pemetrexed in patients with non - squamous histology , and docetaxel or erlotinib , irrespective of histology or egfr status.4 the effect on survival of second - line therapies is generally poor , with the only exception of egfr - tkis in patients with egfr mutations , or crizotinib in individuals with alk rearrangement only in patients in which these agents were not used as front - line therapy.58 hence , there is an urgent need for new , effective , and well - tolerated therapies for nsclc , particularly in the second - line setting .
in addition to the targeted therapies mentioned above , recent insight into the molecular biology of cancer and mechanisms of tumorigenesis suggested the angiogenesis as a promising target for nsclc treatment .
the development of inhibitors of angiogenesis , also known as vessel - directed cancer treatments , has become , over the last few years , a major challenge .
there are two different types of vessel - directed cancer treatments : the vascular targeting agents and the vascular disrupting agents .
the first group belong the antiangiogenic drugs , such as the anti - vascular endothelial growth factor ( vegf ) monoclonal antibody bevacizumab ( avastin ; genentech - roche , south san francisco , ca , usa ) , and the vegf receptor ( vegfr ) tyrosine kinase inhibitors , such as sunitinib ( sutent ; pfizer , new york , ny , usa ) and sorafenib ( nexavar ; bayer healthcare pharmaceuticals , leverkusen , germany ) .
the vascular targeting agents inhibit the formation of additional vessel from existing vasculature , mainly at the outer edge of a growing tumor , and also normalize the constitutively complex network of tumor vasculature , potentially improving the delivery and efficacy of chemotherapy.9 bevacizumab , in combination with platinum - based chemotherapy , has been shown to improve survival versus chemotherapy alone in a first - line setting in patients with non - squamous nsclc10,11 and currently is the only antiangiogenetic drug approved by several regulatory agencies .
in contrast , vascular disrupting agents ( vdas ) are directed against existing vessels , mainly in the tumor center,12 enhancing the cytotoxicity of chemotherapy and ionizing radiation , of which efficacy is decreased by interstitial pressure and hypoxia . although currently under worldwide clinical investigation , these drugs are not approved for cancer treatment.13 vdas can furthermore be divided into two classes : small molecules and ligand directed drugs .
small molecules act as microtubule destabilizers and cytokine inducers , while ligand - directed drugs target specific markers of malignant vasculature .
bavituximab is a vascular disrupting agent with a unique mechanism of action resulting in a high degree of specificity for tumor blood vessels.14 specifically , bavituximab is an unconjugated , chimeric immunoglobulin g1 ( igg1 ) monoclonal antibody directed against the phosphatidylserine ( ps ) , an anionic membrane phospholipid expressed on tumor endothelium .
physiologically , ps is present in the membranes of all eukaryotic cells and involved in signalling , mainly in an extracellular context such as during apoptosis .
ps is not evenly distributed throughout all cellular membranes , nor equally distributed between leaflets of a membrane bilayer . in healthy cells
ps is restricted to the inner membrane leaflet , thanks to adenosine triphosphate ( atp)-dependent aminophospholipid translocases that catalyze the transfer from the external to the internal plasma membrane.15 several pathophysiologic processes , such as apoptosis , cell activation , and transformation , determine the external exhibition of ps,16 due to aminophospholipid translocases inactivation , or scramblases and abc floppases activation.17 once external , ps acts as one major eat me signal , ensuring efficient recognition and uptake of apoptotic cells by phagocytes and promoting the secretion of such anti - inflammatory cytokines as interleukin-10 and transforming growth factor beta ( tgf- ) .
hypoxia and acidity , typical tumor characteristics , also trigger these processes due to the generation of the reactive oxygen species . subsequently , ps exposure could be considered a feature of cancer cells and tumor vessel endothelium.18 because of their large size and hydrophilic nature , monoclonal antibodies such as bavituximab do not pass through the plasma membrane and are unable to recognize and bind intracellular targets , an event that is possible once ps is external . specifically , bavituximab binds ps when recognizing a complex formed by ps and two cross - linked molecules of the ps - binding protein beta 2 glycoprotein-1 ( beta 2gp1).19
bavituximab , once bound , starts up host effector activities such as antibody dependent cellular cytotoxicity , causing vessel destruction and enhancing antitumor immunity .
relevant preclinical studies have been conducted with 3g4 , a mouse immunoglobulin g3 monoclonal antibody similar to bavituximab that specifically recognizes anionic phospholipids.17 histologic examination of orthotopic human mda - mb-231 tumors from mice treated with 3g4 revealed a significant reduction of neoplastic vascular density and plasma content.20 localization of 3g4 to tumor vessels preceded macrophage binding to tumor vessels , impairment of vascular function , and development of necrosis .
the central necrosis with a peripheral circle of surviving tumor cells is a characteristic pattern of tumor cell killing by vascular targeting agents . indeed , vascular targeting agents are thought to be most effective against central vessels , where the high interstitial pressure contributes to vascular collapse , contrary to many anticancer therapies which are effective in the well - oxygenated and peripheral areas of the tumor .
combining vascular targeting agents with antiproliferative antitumor therapies could thus have an additive or even synergistic antitumor activity .
moreover , histologic examination revealed a marked presence of blood monocytes to tumor vascular endothelium and profuse infiltration of macrophages into the tumor interstitium , consistent with the fact that 3g4 enhances the rate of phagocytosis of phosphatidylserine - expressing cells by bone - marrow derived mouse macrophages in a fragment crystallizible ( fc)-dependent fashion.21 taken together , these aspects could raise the possibility that 3g4 causes macrophage cytotoxicity against tumor vessels or tumor cells in mice indirectly , suggesting that the antibody is not directly cytotoxic .
two mechanisms of macrophage - mediated damage to tumor vessels or tumor cells seem feasible .
firstly , 3g4 may bind to exposed anionic phospholipids on tumor vessels and tumor cells , stimulating the binding of monocytes and macrophages via fragment crystallizible gamma ( fc - g ) receptors and enhancing antibody dependent cell - mediated cytotoxicity .
secondly , 3g4 may block phosphatidylserine - mediated quiescence signals , inducing macrophages to secrete tumor necrosis factor- , interleukin-1 , and other inflammatory cytokines that directly damage tumor endothelium and recruit further host cells into the tumor.20 in addition , bavituximab provides anticancer effects by reversing the immune and inflammatory suppression exerted by tumors .
if exposed , ps reduces the production of proinflammatory cytokines while ps targeting counteracts these processes , promoting proinflammatory pathways , recruitment of tumoricidal m1 macrophages , dendritic cell maturation , and antigen presentation.17 as ps performs a crucial role in the binding and activation of coagulation factors , a careful screening for an increased bleeding or thrombogenic risk has been conducted from the first studies . unlike the pathologic antiphospholipid autoantibodies directed against cardiolipin and beta 2 glycoprotein-1 ( beta 2gp1 ) , bavituximab targets domain ii of beta 2gp1
, preserving its circulating and inactive conformation not correlated with antiphospholipid antibody syndrome in preclinical models.22 however , bavituximab prolongs activated partial thromboplastin time ( aptt ) assays in vitro due to the binding to the phospholipid activator in the assay .
transient prolongations in the aptt were evidenced in rats at bavituximab doses 20 mg / kg ( corresponding approximately to a maximum concentration [ cmax ] of 345 g / ml ) . based on these results in the first phase i trial of bavituximab , conducted on 26 pretreated cancer patients ,
dose escalation was capped at 3 mg / kg ( simulated cmax in humans = 65.4 g / ml).23 all six patients treated at the 3 mg / kg dose experienced a transient aptt prolongation and none in lower dose levels . in all patients , the aptt normalized by day three following the bavituximab dosing , consistent with the half - life of bavituximab .
an increase in d - dimer level was evidenced in about half the patients , not temporally associated with the drug administration and not predicting thrombotic occurrences .
twenty - five patients ( 96% ) had assessment of platelet function by platelet function analyzer 100 ( pfa-100 ) analysis . a prolongation of normal baseline pfa-100 after bavituximab administration occurred in one patient in the 3 mg / kg dose cohort .
platelet activation markers , as pac-1 and p - selectin , were unchanged in response to bavituximab therapy in the two patients evaluated .
the pharmacokinetics of bavituximab have been assessed in a recently published phase i open - label , dose - escalation trial.23 the dose levels selected were 0.1 , 0.3 , 1 , and 3 mg / kg , with a starting dose defined on the basis of single- and repeat - dose rodent and primate toxicity studies , and efficacy data obtained in a tumor bearing mouse model .
dose escalation to the biologically effective dose rather than the maximum tolerated dose ( mtd ) was the goal of this study .
this approach takes into account that for monoclonal antibodies the mtd may not correspond to optimal efficacy and , in some instances , may never be reached in monotherapy studies.24 in animal models , maximal efficacy of anti - ps antibody was achieved at doses of 0.5 mg / kg 3 times weekly , yielding a cmax of 5.5 mg / ml with a half - life of 48 hours and a simulated average blood concentration of 2 mg / ml . overcoming this dose , ps binding was presumably saturated , in line with the in vitro evidence of ps - expressing cell saturation at 1 to 2 mg / ml bavituximab concentration . moreover
, aptt transient elevations were noted in rats at bavituximab doses of 20 mg / kg or more ( cmax 345 mg / ml ) .
therefore , capping the dose escalation at 3 mg / kg ( with simulated cmax in humans of 65.4 mg / ml , corresponding to an equivalent cmax of 11111 mg / ml in rodents ) guaranteed a more than 5-fold safety value , providing drug concentrations over the therapeutic range . accordingly with the defined dosing schedules , bavituximab was infused to patients in the first two dose cohorts ( 0.1 and 0.3 mg / kg ) on day 0 , followed by a 28-day washout , and then once weekly for three weeks ( on days 28 , 35 , and 42 ) , following patients until day 70.23 the study was subsequently amended avoiding the 28-day washout .
thus , patients in the 1 and 3 mg / kg dose cohorts have been treated with bavituximab on days 0 , 7 , 14 , and 21 and then followed until day 56 .
dose escalation was permitted if dose - limiting toxicity ( dlt ) occurred in one or none of six patients and serum bavituximab levels did not exceed a predetermined threshold .
the mtd was defined as the highest dose level at which a dlt was experienced in less than 33% of patients .
dlts were defined as any of the following adverse events observed through day 56 or 70 ( depending upon cohort ) : grade 3 or greater hematologic or non hematologic toxicity , grade 2 or greater prolongation of prothrombin time / international normalized ratio ( pt / inr ; > 1.5 upper limit of normal [ uln ] to 2 > uln ) , grade 3 or greater prolongation of aptt ( > 2 uln ) .
bavituximab exhibited linear single - dose ( day 0 , for all cohorts ) and multiple - dose ( for the 1 and 3 mg / kg cohorts on day 21 ) pharmacokinetic characteristics . after time to peak concentration ( tmax ) ,
mean serum bavituximab concentrations seemed to decline in a monoexponential manner , with similar concentrations on days 0 and 21 within dose groups with a half - life of approximately two days , somewhat shorter than that of other chimeric ( ie , 65% human and 35% mouse ) antibodies such as cetuximab ( half - life four days ) .
this difference could be correlated with the clearance of b2gp1 as bavituximab s target : differently from soluble targets such as vegf , ps is static and saturable , so bavituximab levels may not necessarily need to be maintained over a prolonged period . whereas all patients experienced at least one adverse event , the most frequent were fatigue ( 27% ) , nausea ( 15% ) , aptt prolongation ( 12% ) , and pyrexia , rash , and dyspnea ( each 8% ) , mainly grade 1 or 2 and occurring with similar frequency across dose cohorts .
ten patients ( 38% ) showed at least one grade 3 or 4 adverse event .
one patient experienced a pulmonary embolism considered related to treatment in the 3 mg / kg dose cohort , and was the only dlt observed in the study .
another patient in the 3 mg / kg dose cohort developed grade 3 hypertension considered not causally related to bavituximab .
the authors concluded , therefore , that bavituximab can be safely administered weekly , with low risk of infusion reactions . on the basis of sustained achievement of predicted therapeutic concentrations , both the 1 and 3 mg / kg doses
are recommended for subsequent monotherapy and combination trial with a close clinical monitoring for thromboembolic phenomena and laboratory monitoring for antiphospholipid effect , in consideration of the case of pulmonary embolism that occurred .
clinical data regarding the efficacy of bavituximab was initially derived from the aforementioned phase i study . of the 26 patients enrolled and affected by cancer of the breast ( n=13 ) , colorectal ( n=4 ) , pancreas ( n=3 ) , and hepatocellular , head and neck , melanoma , mesothelioma and prostate ( n=1 each ) , 18 were evaluable , presenting as eight stable disease and ten progressive disease , according to revised response evaluation criteria in solid tumors ( recist ) guideline ( version 1.1 ) recist criteria .
there were no objective responses , similarly to efficacy data regarding other vascular targeting monoclonal antibodies . in subsequent phase
ib , which enrolled 14 patients with refractory advanced solid tumors , bavituximab ( b ) was given weekly for up to 8 weeks , at a dose of 3 mg / kg , in combination with docetaxel ( d ) ( 7580 mg / m every 3 weeks ) or gemcitabine ( g ) ( 1,000 mg / m in weeks 17 ) , or paclitaxel ( 175 mg / m every three weeks ) plus carboplatin ( appropriate use criteria [ auc ] = 5 ) ( p + c ) .
study objectives were to evaluate the safety , tolerability and pharmacokinetic profile of b when combined with chemotherapeutic agents .
serum levels of b were determined by enzyme - linked immunosorbent assay ( elisa ) .
five patients received b + d , five patients received b + g , and four patients received b + p + c. the most common adverse events were vomiting ( six patients ) , cough ( four patients ) , asthenia , pain , headache , neutropenia , prolonged aptt , and pain in extremities , each in three patients , with three serious adverse events ( saes ) considered related to b. in accordance with recist criteria , among the twelve evaluable patients there was partial response ( three patients ) , stable disease ( three patients ) , and progressive disease ( six patients ) . regarding the pharmacokinetic profile , no significant differences were seen between the three treatment groups following administration of b on days 0 and 21 ; no accumulation of b was seen following multiple dose administration.25 on the basis of these results ( table 1 ) , a randomized , blinded , placebo - controlled phase ii trial of d plus b as second - line treatment in locally advanced or metastatic nsclc patients was conducted.26 one hundred and twenty - one patients were randomized 1:1:1 to receive d at 75 mg / m every 21 days for up to 6 cycles in combination with blinded infusions of placebo ( p ) , b at 1mg / kg , or b at 3
the primary endpoint was overall response rate ( orr ) , while secondary endpoints were progression - free survival ( pfs ) and overall survival ( os ) .
after the study unblinding , a pharmacokinetic predefined analysis revealed phial coding discrepancies in the placebo and b at 1 mg / kg phials ; consequently data from these two cohorts were pooled forming the control arm ( c arm ) . between the 41 patients treated with b at 3 mg / kg plus d , representing the experimental arm , and the other 80 patients into the c arm , there were no significant differences in age , sex , ethnicity or disease stage .
available data , collected at 54% of death events reported in the experimental arm and 71% in the c arm , demonstrated 17.1% and 13.8% orr , respectively .
regarding secondary endpoints , median pfs was 4.5 months and median os was 11.7 months for 3 mg / kg b + d arm ; median pfs was 3.3 months , and median os was 7.3 months for c arm ( table 2 ) .
the safety profile for 3 mg / kg b + d was similar to that of c arm in severity and frequency , representing the planned dose for the phase iii trial . the sunrise ( stimulating immune response through bavituximab in a phase iii lung cancer study )
is the phase iii global , randomized , double - blind , placebo - controlled clinical trial , recently opening to enrollment in more than 100 clinical sites worldwide , which randomized , in 1:2 fashion , to bavituximab plus docetaxel versus docetaxel plus placebo as second line in approximately 600 patients with stage iiib / iv non - squamous nsclc .
all patients will receive up to six 21-day cycles of docetaxel ( 75 mg / m ) plus weekly infusions of either bavituximab ( 3 mg / kg ) or placebo until progression or toxicity .
bavituximab was granted the fast track designation by the us food and drug administration ( fda ) for the potential treatment of second - line nsclc .
bavituximab has also been studied in the frontline setting . in a phase ii trial27 which enrolled 49 indian patients with untreated locally advanced or metastatic nsclc
, the antibody , at a weekly dose of 3 mg / kg until disease progression , was tested in combination with carboplatin and paclitaxel , at a dose of auc = 5 and 175 mg / m , respectively , on day 1 up to six 21-day cycles .
the study used a simon 2-stage design and demonstrated an orr ( complete response + partial response ) in the initial group of 11/21 ( 52.4% ) , with clinical complete response in 4.8% and partial response in 47.6% . according to available data ,
median pfs in the first 21 patients treated is 6.2 months ; median duration of response and median overall survival have not yet been presented .
adverse events ( aes ) have been reported by 44/49 ( 89.8% ) treated subjects , the most common being pyrexia ( 28.6% ) , diarrhea ( 26.5% ) , alopecia ( 26.5% ) , anemia ( 22.4% ) , neuropathy ( 20.4% ) , and pain ( 20.4% ) with mild or moderate severity .
forty - five saes have been evidenced in 19 subjects , including two deaths due to myocardial infarctions and one death due to hemoptysis , which occurred in a subject with squamous histology , whereupon the accrual of squamous cell carcinoma ceased . on the basis of the promising result of 52% orr using recist criteria in an initial group ,
the combination with carboplatin and paclitaxel has been evaluated in a recently - concluded phase ii randomized trial ( nct01160601 ) , which accrued a total of 86 subjects in the united states , the republic of india , the republic of georgia , the russian federation , and ukraine .
the trial randomized patients with up to six cycles of carboplatin ( auc = 6 ) plus paclitaxel at 200 mg / m with or without bavituximab 3 mg / kg weekly until intolerable toxicities or disease progression .
another combination , specifically carboplatin , pemetrexed and bavituximab , is studied in the same setting in a recently opened phase i trial ( nct01323062 ) .
angiogenesis , thanks to progressive insight into the molecular biology of cancer and mechanisms of tumorigenesis , is a promising target for nsclc treatment , and the development of vessel - directed cancer treatments has grown enormously in recent years .
these treatments can be divided into two different classes : the vascular targeting agents ( such as bevacizumab , the only antiangiogenetic drug today approved for nsclc treatment ) , and the vascular disrupting agents such as bavituximab .
bavituximab is a an unconjugated , chimeric immunoglobulin g1 ( igg1 ) monoclonal antibody directed against the phosphatidylserine ( ps ) expressed on tumor endothelium and segregated to the inner membrane leaflet .
once exposed on the external membrane , due to various pathophysiologic processes , ps can be bound by bavituximab , which starts up host effector activities such as antibody dependent cellular cytotoxicity , resulting in vessel destruction and enhanced antitumor immunity .
on the basis of promising preclinical activity and an acceptable safety profile , bavituximab is currently under investigation in combination with chemotherapy for advanced nsclc in several trials .
the second - line setting studies are of particular clinical interest . specifically , a recently presented phase ii randomized , placebo - controlled trial of bavituximab plus docetaxel suggested a positive trend favoring the combination , with orr of 17% , median pfs more than 4 months , and median os more than 11 months . these results , although initial and needing confirmation by the currently ongoing phase iii trial , are promising and similar to data recently published with docetaxel plus nintedanib , an oral angiokinase inhibitor , in the same setting.28 this latest trial demonstrates a significant os benefit , thus is different from other antiangiogenic compounds that have been tested in the second - line setting , such as vandetanib,29 sunitinib,30 or aflibercept,31 despite pfs improvements . in view of the hypothetical association of antiphospholipid antibody syndrome with cases of thrombosis and bleeding occurring in earlier studies ,
a principal limitation of available studies is the lack of biomarker data , which represents an urgent major challenge .
although in vitro aptt prolongation provides some pharmacodynamic data , the association between this laboratory finding and therapeutic effect is not known . to provide more insight into the mechanism of bavituximab in humans , dynamic contrast
enhanced magnetic resonance imaging ( mri ) scans could be incorporated into selected ongoing and future bavituximab clinical trials .
similarly , the available studies did not include biomarkers of antitumor immunity , which represents another proposed mechanism of bavituximab therapeutic effect . in conclusion , available data regarding the use of bavituximab for the treatment of metastatic and refractory nsclc make an important contribution in cancer treatment research by adding another agent to the armamentarium of drugs .
it is hoped that the use of more comprehensive study designs incorporating tissue- , blood- , and imaging - based assays will result in even more clinically relevant results . | ### Summary:
: bavituximab is a an unconjugated , chimeric immunoglobulin g1 ( igg1 ) monoclonal antibody directed against the phosphatidylserine ( ps ) expressed on tumor endothelium , with a specific mechanism of action .
ps is an anionic membrane phospholipid , physiologically restricted to the internal membrane leaflet ; various pathophysiologic processes cause the exposure of ps on the external membrane leaflet .
bavituximab , once bound , starts up host effector activities , such as antibody dependent cellular cytotoxicity , causing vessel destruction and enhancing antitumor immunity .
phase i clinical trials of bavituximab administered as monotherapy or in combination with other chemotherapeutic agents in adults with pretreated solid tumors have been accomplished , indicating that bavituximab can be safely dispensed weekly , with a recommended dose of 1 and 3 mg / kg . a phase ii randomized , placebo - controlled trial of bavituximab plus docetaxel , in the second - line therapy setting of locally advanced or metastatic non - small - cell lung cancer , has been conducted and recently presented , suggesting a clinical benefit of the combination , with an overall response rate of 17% and median overall survival of more than 11 months .
a phase iii trial is currently ongoing .
bavituximab has been studied in combination with platinum - based doublets with promising results . in the present paper
we summarize the preclinical development and clinical experience with bavituximab in non - small - cell lung cancer . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: whole body magnetic resonance imaging ( wb - mri ) has been used for tumor detection in several clinical settings , primarily for cancer staging and the detection of metastatic disease ( both visceral and bone metastases ) [ 18 ] .
a recent application for wb - mri includes the detection of peripheral nerve sheath tumors ( pnsts ) and the assessment of tumor burden in syndromes with a predominance of multifocal pnsts , such as the nf syndromes , including nf-1 , nf-2 , and schwannomatosis ( swn ) [ 913 ] . for such applications ,
a typical wb - mri protocol includes noncontrast t1 and short tau inversion recovery ( stir ) , and has thus far been performed utilizing 1.5 telsa ( t ) systems with good diagnostic capability .
however , with the development of new therapeutics there is an increasing demand to measure not only size , but also the biologic properties of these tumors . in particular , functional mri parameters that include molecular , vascular , and metabolic - based measures
are available with diffusion weighted imaging ( dwi)/apparent diffusion coefficient ( adc ) mapping and dynamic contrast - enhanced mri and may be applicable to assessing tumor biology longitudinally as well as in response to specific therapies [ 8 , 14 ] .
there are several reports in the literature regarding the feasibility of using functional wb - dwi in cancer [ 35 , 7 , 8 , 1526 ] , but these techniques have not been explored in benign tumors such as pnsts . the purpose of this study is to show the feasibility of performing functional wb - mri at 3 t inclusive of traditional t1-weighted ( t1w ) and short tau inversion recovery ( stir ) sequences as well as quantitative dwi with adc mapping and contrast - enhanced t1-weighted sequences .
we hypothesized that wb - dwi and wb - contrast - enhanced sequences could be successfully performed in greater than 80% of patients , and offer functional lesional features not provided by standard wb - stir and t1w , which is important to the characterization of peripheral masses .
institutional review board approval and written informed consent were obtained for this prospective hipaa - compliant study .
wb - mri at 3 t including quantitative dwi with adc mapping and postcontrast t1-weighted imaging was performed in 11 patients who met clinical diagnostic criteria for nf-2 or swn ( table 1 ) .
image quality ( table 2 ) , a determinant of study feasibility , was reviewed by two investigators , and the presence and character ( signal , enhancement characteristics , and adc values ) of peripheral lesions were recorded .
patients who had presented for clinical evaluation to a specialty clinic with possible nf-2 or swn were targeted for recruitment by a neurooncologist .
inclusion criteria were suspected or confirmed nf2 or swn patients who were referred for wb - mri for the assessment of tumor burden , no contraindication to mri , and no prior systemic therapy for nf2 or swn .
exclusion criteria were contraindications to mri and prior systemic therapy for nf2 or swn .
all studies were performed with a dedicated clinical research 3 t scanner ( timtrio , siemens medical systems , malvern , pa , usa ) using the total imaging matrix ( tim ) .
this technology enables the application of multiple phased - array surface coils and receiver channels for parallel imaging with an increased signal - to - noise ratio in three spatial directions while acquiring sections of the body from the head down to the mid femur .
the total scan range of 205 cm was obtained by combining the large field of view ( 400500 mm ) with automatic table motion . in the coronal plane , four to six areas were scanned . the wb - mri protocol ( shown in figure 1 ) consisted of t1-weighted sequences ( volume interpolated breath - hold examination ( vibe ) , tr / te = 0.88/2/43 ms , field of view = 50 50 cm , matrix = 256 256 , slice thickness = 2 mm ) , short tau inversion recovery ( stir , tr / te = 6640/84 ms , field of view = 50 50 cm , matrix = 256 256 , slice thickness = 2 mm with interpolation ) , and quantitative dwi ( tr / te = 4100/70 ms , b = 50 , 400 , 800 s / mm , field of view = 50 50 cm , averages = 4 , acceleration factor = 2 , slice thickness = 5 mm , bandwidth = 1900 khz , phase encode lines = 24 , echo spacing = 0.640.88 ) with adc mapping .
the acquisition of different b - values allowed for the creation of trace adc maps on a pixel - by - pixel basis for quantitative analysis according to the following equation :
( 1 ) adc=i=1nln(si / s0)bi ,
where bi = the diffusion gradient values , b = g( /3 ) , = gyromagnetic ratio , g = gradient strength , = diffusion gradient duration , = time between diffusion gradient pulses , s0 = 1st image ( b = 0 ) , and si = ith image . the dwi sequence b value of 50 s / mm was chosen to reduce perfusion effects and the remaining two b values were chosen to obtain an accurate adc measurement .
subsequently , a postcontrast t1-weighted sequence ( vibe , tr / te = 0.88/2/43 ms , fov = 50 50 cm , matrix = 256 256 , slice thickness = 2 mm ) was obtained after intravenous administration of 0.1 mmol / kg gadodiamide contrast agent ( magnevist , bayer schering pharma ag , germany ) .
the contrast agent was injected over 10 seconds with imaging beginning immediately after completion of the injection .
prior to acquisition of the sequences , whole body shimming was performed . if excessive image noise was identified at the time of acquisition , localized fast shimming was performed as needed .
figure 2 is an example of the need for localized fast shimming that was performed for improved diagnostic quality .
all t1-weighted imaging , stir , and postcontrast t1 imaging were acquired in the coronal plane with isotropic resolution ( t1 vibe ) or near - isotropic resolution ( stir ) , allowing reconstruction into axial and sagittal planes for interpretation .
all imaging was respiratory - gated using 2d prospective acquisition correction ( pace ) technique to minimize artifacts related to respiratory motion .
two readers , one with 10 years experience in musculoskeletal imaging and one with 8 years experience specifically in wb - mri technique and interpretation , reviewed the images in consensus , ( for image quality , lesion detection , and lesion characterization ) .
all imaging planes were reviewed ( coronal as well as reconstructed axial and sagittal views ) .
first , readers recorded the diagnostic quality for each study , by body part ( chest , abdomen , pelvis , thighs , thoracic spine , lumbar spine , neck , and calves and arms if the latter two were included by imaging ) .
quality was assessed using a semiquantitative scale , ranging from 1 to 4 , with the quality criteria listed in table 2 .
second , readers reviewed the imaging and recorded whether peripheral lesions were present or absent , and whether each lesion was visible on every sequence ( t1 , stir , dwi / adc map , and postcontrast t1 ) .
stir images were reviewed first , followed by dwi / adc maps and then , t1 images with and without contrast .
a lesion was defined as any mass - like abnormality of increased stir signal and was subsequently confirmed on t1-weighted and dwi sequences . only peripheral lesions greater or equal to 1 cm seen in at least two planes were recorded for the purpose of this analysis .
dwi and t1-weighted sequences were also reviewed independently and readers recorded whether additional lesions or incidental abnormalities in other organs were found on these sequences .
readers characterized each peripheral mass by recording whether each lesion met criteria for a pnst ( showed evidence of internal enhancement following contrast administration ) or a cyst ( showed no evidence of enhancement following contrast administration ) .
readers recorded other characteristics of the lesions including the size , location ( chest , abdomen , pelvis , thighs , thoracic spine , lumbar spine , neck , calves , or arms ) , shape ( ovoid or irregular ) , and margin ( well - defined , partly defined , ill - defined ) of each peripheral lesion . the presence or absence of a target sign , a split fat sign , and
signal characteristics relative to muscle on t1-weighted images , stir and contrast - enhanced imaging ( hypointense , isointense , and hyperintense ) were recorded along with degree of heterogeneity ( homogeneous and less than 25% heterogeneous , moderately heterogeneous with 25%75% heterogeneity , and markedly heterogeneous with greater than 75% heterogeneity ) .
the presence or absence of associated muscle denervation ( increased intramuscular signal on stir or the presence of atrophy on t1-weighted imaging ) was also recorded .
the character of the lesion regarding its relationship to the adjacent nerve ( eccentric or central ) was sought and recorded when possible . for diffusion weighted images ; readers assessed the presence or absence of heterogeneity and the presence or absence of the target sign on the adc maps .
minimum , average , and maximum adc map values ( with standard deviation ) were recorded for each peripheral lesion .
the latter was accomplished by placement of a region of interest to encompass as much of the whole lesion as possible , with exclusion of surrounding tissues .
adc map measurements were made on one section through the center of the lesion , to avoid volume averaging artifact .
descriptive statistics were reported regarding subject demographics , image quality for all body locations , number of lesions , lesion location , and lesion characteristics on the anatomic and functional sequences ( signal intensity , heterogeneity , the presence or absence of specific signs described above , and adc values ) .
table 3 summarizes the diagnostic quality ratings for each sequence , by body part .
overall , taking all body parts into account , including the spine and neck , diagnostic quality was the highest for t1-weighted sequences ( mean 3.95 0.36 ) and the lowest for dwi ( mean 2.53 0.77 ) , across all subjects .
for stir , diagnostic quality was an average of 3.51 0.50 , with no quality measurement less than 3 .
quality measures were the lowest for the neck and the highest for the abdomen and pelvis , for all sequences .
the calves were incompletely included in the field of view of 8 subjects ( 8/10 patients with nf-2 ) and the arms were incompletely included in 11 subjects ( 9/10 patients with nf-2 , 1 patient with swn , and 1 volunteer ) .
an example of shimming artifact that interfered with the quality of the image is shown in figure 2 . in table 1 ,
a total of 23 lesions ( median 3.5 cm , range 1.010.2 cm ) were identified ; no additional lesions were detected on the t1-weighted or dwi sequences if they were not detected on stir .
lesions were present in the chest ( n = 7 ) , abdomen ( n = 4 ) , pelvis ( n = 4 ) , thighs ( n = 4 ) , arm ( n = 1 ) , thoracic spine ( n = 1 ) , and lumbar spine ( n = 2 ) .
on postcontrast t1-weighted images , 21/23 lesions met criteria for a pnst ( enhancement following contrast administration ) , while 2/23 met criteria for a cyst ( no evidence of enhancement following contrast administration ) . compared to skeletal muscle on t1-weighted images , cysts were all homogeneously hypointense , while pnsts were homogeneously isointense ( n = 5/23 ) or hypointense ( n = 16/23 ) . on stir , cysts were homogeneously hyperintense , while pnsts were all hyperintense but with variable heterogeneity ( 10 homogeneous , 8 moderately heterogeneous , and 3 markedly heterogeneous ) . on stir ,
the target sign was present in 6/23 cases , the split fat sign was present in 3/23 cases , and perilesional edema was absent in all cases .
muscle denervation was present in 2 cases , in the thigh musculature . in 2/21 tumors ,
the relationship of the tumor to the adjacent nerve could be resolved and was eccentric to the nerve ; in all other tumors , the border with the adjacent nerve was not clearly identified .
on postcontrast t1 , tumor enhancement was homogeneous in 14/21 , moderately heterogeneous in 6/19 , and markedly heterogeneous in 1/21 . on diffusion weighted images and adc maps , 23/23 lesions had diagnostic quality to allow evaluation .
all cysts ( 2/2 ) were homogeneously hyperintense , while 12/21 pnsts were homogeneously hyperintense and 9/21 pnsts were moderately heterogeneous in signal intensity .
the target sign was present in 2/21 pnsts ( compared with 6/23 by stir ) . for cysts ,
the mean minimum adc map value was 2.4 0 10 mm / sec ( range 2.4 - 2.4 ) , the mean average adc map value was 2.6 0.16 10 mm / sec ( range 2.6 - 2.6 ) and the mean maximum adc value was 2.8 0 10 mm / sec ( range 2.8 - 2.8 ) . for pnsts ,
the mean minimum adc map value was 1.36 0.46 10 mm / sec ( range 0.82.2 ) , the mean average adc value was 1.89 0.53 10 mm / sec ( range 1.22.7 ) , and the mean maximum adc value was 2.66 0.88 10 mm / sec ( range 1.43.9 ) .
figure 1 shows the subject in whom the arms were included and a pnst was identified in the arm .
figure 3 illustrates results in a subject with nf-2 who had peripheral tumors and paraspinal cysts ; the cysts could not be distinguished from pnsts on t1 or stir but were distinguished by contrast - enhanced t1 and adc mapping , underscoring the utility of intravenous contrast and dwi for characterizing peripheral lesions .
wb - mri with quantitative dwi / adc mapping and contrast - enhanced sequences at 3 t is feasible with high diagnostic quality in patients with pnsts .
the application of this technique to patients with nf2 and swn is promising , as these additional sequences may advance the utility of wb - mri not only to include anatomic detection , but also provide quantitative metrics for biologic characterization .
the mri features given by wb - dwi and contrast - enhanced sequences allow for the characterization of tumor cellularity and vascular status . in previous studies of patients with nf syndromes , wb - mri
was implemented to counteract the need for separate scans of the chest , abdomen , pelvis , and thighs and has been utilized for the detection of peripheral tumors and the determination of disease burden [ 9 , 1113 , 29 , 30 ] . in these studies ,
wb - mri was performed at 1.5 t and focused on t1 and stir sequences .
mautner et al . additionally implemented wb - mri technique with localized contrast - enhanced sequences at 1.5 t in nf-1 patients for the assessment of disease burden and identification of malignant peripheral nerve sheath tumors . in this study , we assessed the feasibility of expanding wb - mri techniques to incorporate functional measures with dwi and adc mapping as well as contrast - enhancement properties .
the advantages of performing such studies at 3 t include the available increased signal compared with 1.5 t , which affords a trade - off for spatial resolution and the ability to perform faster acquisitions with isotropic resolution for the anatomic sequences ( vibe , stir ) .
similar acquisitions at 1.5 t will require more scanner time and make the scan more susceptible to motion artifacts .
in addition , the increased signal available at 3 t is theoretically advantageous for acquiring dwi , although susceptibility artifacts may occur with greater frequency at 3 t compared with 1.5 t .
advances in shimming techniques and the use of a continuous table for wb - mri , rather than separate station acquisitions , will likely further improve the quality of wb - dwi . in our study subjects ,
wb - dwi was acquired with acceptable diagnostic quality , although , for most cases , artifact at the edge of the image was present due to the large field of view . for the interpretation of peripheral tumor biology with adc values in our study , such artifact was not limiting and may be inconsequential to the majority of patients . regarding technical factors for performing 3 t functional wb - mri ,
the coronal plane was chosen for all acquisitions as it inherently combats respiratory motion artifact compared with the axial plane .
since the anatomic sequence ( t1 vibe , stir ) acquisitions are performed with isotropic or near - isotropic resolution , the datasets can be reconstructed into the axial and sagittal planes ( as well as any other oblique plane of interest ) with the same resolution as the original acquisition . for detailing the anatomy ,
our wb - mri protocol offers good spatial resolution ( 2 mm slice thickness ) . for dwi
, the acquisition is performed at 5 mm thickness to ensure adequate quality ; as dwi is a functional sequence , high spatial resolution is likely less critical .
we have demonstrated in this report that peripheral lesions were detectable on the anatomic noncontrast t1 , stir , and postcontrast t1 sequences as well as the dwi sequences and adc maps .
unlike the use of wb - mri for tumor detection , the addition of contrast - enhanced t1 and dwi sequences enables the characterization of peripheral lesions .
first , a common challenge with noncontrast sequences is the differentiation of a tumor from a cyst ; with the addition of contrast , the distinction is clear , since tumors enhance with contrast , while cysts do not .
dwi offers a theoretical advantage in this regard also , as cysts will likely have a higher adc map value than tumors given that the adc is a measure of cellularity .
furthermore , if intravenous contrast is contraindicated or can not be administered , dwi with adc mapping can serve as a potentially useful sequence for distinguishing cysts and tumors .
second , the natural behavior of pnsts in nf2 and swn is variable between and within patients , with some peripheral tumors having an indolent course and others having a more aggressive course . with the advent of wb - dwi and contrast enhancement , metrics are available which may increase our understanding of tumor biology and the association with clinical behavior in the peripheral tumors of these patients .
interestingly , the contrast enhancement pattern in the subject with swn ( moderately and markedly heterogeneous lesional enhancement ) was different from that of the subjects with nf2 ( homogeneous lesional enhancement ) , perhaps reflecting a difference in tumor biology , although longitudinal data is not available on these subjects at this time .
third , the features of peripheral tumors by dwi and contrast - enhanced sequences may ultimately prove useful for determining response to treatment , by assessing changes in the adc values or contrast - enhancement characteristics following treatment .
currently , only changes in size are used to identify treatment response in the nf syndromes , but wb - dwi has been described for the assessment of treatment response in other disorders such as bone metastases [ 13 , 23 , 31 , 32 ] , multiple myeloma , lymphoma [ 15 , 16 ] , and rosai - dorfman disease . in the patients with nf2 and swn in this study , there was great variability in the adc values of the peripheral schwannomas , presumably due to the differences in cellularity and relative proportion of antoni a and antoni b patterns within each schwannoma . at this time , the utility of wb - dwi and contrast for the assessment of treatment response in the nf syndromes has not been established , as longitudinal studies are needed to determine whether changes in lesional cellularity that may come about following treatment are detectable by alterations in the adc values or contrast - enhancement pattern of a responding peripheral tumor .
a limitation of this study is in the use of multistation acquisitions for the performance of wb - mri , which potentially impacts the quality of shimming and subsequent image acquisition .
the multi - station acquisition requires shimming at each station ; this has the potential of changing the initial shim values , which may affect the homogeneity of the field .
moreover , the incorrect overlap between each station can lead to gaps between major anatomic regions . to overcome these potential problems ,
finally , the visualization of wb - mri data can be a challenge due to the large datasets acquired and methods are being developed to integrate them into one dataset for ease of diagnosis , by creating a multiparametric paradigm in which information from all the sequences is incorporated into one image .
in conclusion , wb - mri is feasible for both tumor detection and characterization when applied to the pnsts seen in patients with nf-2 and swn . by adding quantitative wb - dwi and contrast to the wb - mri protocol , metrics for lesion characterization are now accessible and may help increase our comprehension of tumor biology . in turn , wb - mri may potentially impact clinical outcome by distinguishing the biologically variable pnsts seen in patients with nf syndromes , potentially impacting decisions for treatment and monitoring response to treatment . | ### Summary:
: purpose .
wb - mri is mainly used for tumor detection and surveillance .
the purpose of this study is to establish the feasibility of wb - mri at 3 t for lesion characterization , with dwi / adc - mapping and contrast - enhanced sequences , in patients with neurofibromatosis type 2 ( nf-2 ) and schwannomatosis .
materials and methods . at 3 t
, wb - mri was performed in 11 subjects ( 10 nf-2 and 1 schwannomatosis ) with stir , t1 , contrast - enhanced t1 , and dwi / adc mapping ( b = 50 , 400 , 800 s / mm2 ) .
two readers reviewed imaging for the presence and character of peripheral lesions .
lesion size and features ( signal intensity , heterogeneity , enhancement characteristics , and adc values ) were recorded .
descriptive statistics were reported .
results .
twenty - three lesions were identified , with average size of 4.6 2.8 cm .
lesions were characterized as tumors ( 21/23 ) or cysts ( 2/23 ) by contrast - enhancement properties ( enhancement in tumors , no enhancement in cysts ) .
on t1 , tumors were homogeneously isointense ( 5/21 ) or hypointense ( 16/21 ) ; on stir , tumors were hyperintense and homogeneous ( 10/21 ) or heterogeneous ( 11/21 ) ; on postcontrast t1 , tumors enhanced homogeneously ( 14/21 ) or heterogeneously ( 7/21 ) ; on dwi , tumor adc values were variable ( range 0.82.7 ) , suggesting variability in intrinsic tumor properties . conclusion .
wb - mri with quantitative dwi and contrast - enhanced sequences at 3 t is feasible and advances the utility of wb - mri not only to include detection , but also to provide additional metrics for lesion characterization . |
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: cytochrome c ( cyt c ) is an important
heme protein that functions as an electron carrier within the electron
transport chain . as a model system
electrochemistry has been successfully used as an important
tool to study the functionality of the protein by providing an external
potential to mimic the electron transfer process .
x - ray crystallography
and nmr spectroscopy , on the other hand , are well - known structural
characterization techniques that have been applied to the cytochrome c system . although very useful , they are
not applicable for dynamic studies such as the ones encountered here
because of the lack of temporal resolution .
moreover , it is not possible
for all the proteins to form a well - ordered crystal .
vis reflectance
spectroscopy was used to study the electron transfer rate , and edmiston et al .
utilized fluorescence spectroscopy to determine
the molecular orientation when the protein was bound to a surface .
quartz crystal microbalance ( qcm ) and surface plasmon resonance
( spr ) have also been used to study the electron transfer process of
cytochrome c on a gold electrode modified with different
self - assembled monolayers ( sams ) .
vibrational spectroscopy is very powerful for characterization
of the hydrogen bonding pattern and secondary structure of proteins
and polypeptides .
studied cytochrome c on different sam structures using surface - enhanced infrared absorption
spectroscopy ( seiras ) .
spiro et al . attempted
to provide complete assignment of cytochrome c through
isotope labeling .
a complicating factor
is that cyt c possesses the unique characteristic
that its backbone is strongly infrared - active but hardly detected
using raman spectroscopy , whereas the heme center is raman - active
but gives rise to a very weak infrared signal .
thus , the protein structure
or conformational change can not be entirely described by either technique
alone , which sometimes has led to ambiguous conclusions that are still
debated .
hence , both techniques , raman and infrared , are complementary
techniques as they reveal information about both the protein backbone
and the redox center . two - dimensional ( 2d ) correlation spectroscopy
was first developed
by noda in 1989 and has triggered many research efforts .
it utilizes a mathematical method to plot a series of dynamic spectra
generated by external perturbation ( temperature , time , potential ,
etc . ) on a two - dimensional scale , hence generating two types of plots ,
namely , synchronous and asynchronous .
this technique is advantageous
because it can resolve overlapping peaks and provide information about
the sequence of dipole reorientation / conformational change , etc . for
example
, wu et al . utilized 2d ir spectroscopy to study the thermal
unfolding of ribonuclease a upon reduction and ozaki et al .
used 2d raman spectroscopy to study the molecular
interaction between chemical components in pharmaceutical tablets .
raman analysis also
has been investigated by noda et al . for
the study of n - methylacetamide .
however , most of
the 2d correlation studies have been used to explore the same structural
segment of the molecule .
to the best of our knowledge , the present
work is the first attempt to apply 2d heterospectral correlation analysis
to address different parts of the target protein , which is possible
because of the special characteristics of cytochrome c stated above .
hetero 2d would allow us to correlate the changes
in the infrared and raman spectra .
additionally , combining ir and
raman spectroscopy allows us to probe the sequential pattern of the
conformational changes in cyt c by applying the sequential
rules of 2d correlation spectra .
molecular dynamics calculations are
also performed to examine the interaction between the functional units
probed by the hetero 2d correlation and to reveal details of intramolecular
interactions .
gold(iii ) chloride trihydrate
( aucl33h2o , 99.999% ) , hydroxylamine hydrochloride
( nh2oh hcl , 99% ) , cytochrome c from bovine
heart , sodium perchlorate , 3-aminopropyltrimethoxysilane
( aptms ) , and 2-mercaptoethanol were purchased from sigma - aldrich .
briefly , a 30 nm gold film was deposited by electrothermal evaporation
onto an attenuated total reflection ( atr ) crystal after a thorough
rinse with ethanol and sonication . to grow the second gold layer ,
the substrate was immersed in 50 ml of an aqueous solution containing
0.4 mm hydroxylamine hydrochloride to which 500 l of an aqueous
solution of gold(iii ) chloride trihydrate ( 0.3 mm ) was added .
after
2 min , an equivalent aliquot of the aucl3 solution was
added .
this process was repeated five times such that the sample remained
in the growth solution for a total of 10 min .
the sample was removed
from the growth solution , rinsed with water , and dried in a stream
of nitrogen .
thereafter , the sample was immersed in an aqueous solution
of 2-mercaptoethanol ( me ) ( 1 mm ) for 15 min and then rinsed with water .
subsequently , cyt c was adsorbed for 60 min using
a solution of cyt c ( 0.35 mm ) in pbs buffer ( 20 mm
k2hpo4 and 10 mm naclo4 , ph 7 ) .
all
electrochemical measurements were recorded in a homemade liquid
cell using an autolab instrument ( pgstat302 ) equipped with an ecd
module amplifier for low currents , an adc750 module for rapid scan
measurements , and a scangen module for analog potential scanning ( eco
chemie , b.v . ,
all measurements were collected
using a three - electrode configuration with the gold film as the working
electrode , an ag / agcl , kclsat reference , and a platinum
wire as the counter electrode .
all electrode potentials are reported
relative to the standard hydrogen electrode ( she ) .
the spectroelectrochemical cell was mounted on top of a trapezoidal
silicon atr crystal required for a single reflection in the atr spectroscopy
mode .
the ir beam of the ftir spectrometer ( vertex 70 ftir spectrometer ,
bruker , karlsruhe , germany ) was coupled to a prism at an angle of
incidence = 60. the total reflected beam ir intensity
was measured using a photovoltaic mercury cadmium telluride ( mct )
detector . for the static measurements , the mirror velocity was 120
khz and the resolution was 4 cm ; 1000 scans
the raman experiments were performed on the combined system of
a witec confocal raman microscope using the 532 nm line of a nd : yag
laser with circular polarization .
the laser beam was coupled to a confocal raman
microscope ( alpha 300 , witec ) equipped with a water immersion objective
( nikon 60 * , na = 1.0 , wd = 2.0 ) .
thus , the laser beam was focused ,
and the scattered light was filtered by an edge filter and guided
to the spectrometer ( uhts 300 , witec ) by a 600 grooves / mm grating
to provide the spectral resolution .
the recorded spectrum was imaged
onto a thermoelectrically cooled emccd detector ( witec ) .
the raman
spectra were acquired using a 15 s integration time with a laser power
density of 2.6 10 w / cm with a spot
size of 1 m .
the surface - enhanced raman
spectroscopy ( sers ) spectra were analyzed using the software packages
witec control 1.54 and witec project 2.06 .
the synchronous
and asynchronous 2d plots of the infrared , raman , and heterospectral
correlations were calculated using the software 2d shige ( shigeaki
morita , kwansei - gakuin university , nishinomiya , japan ) .
the color
bar shows the different intensities of the 2d correlation peaks , which
indicates the extent of correlation between x and y variables .
the simulations
were based on the crystal structure of the oxidized form of bovine
heart cytochrome c ( pdb entry : 2b4z ) using the gromos11 software and the gromos 54a7 force field .
the crystal structure was modified by removing
the covalent bond between the heme and his 18 and met 80 , while adding
the thioether bridges to the heme vinyl groups through cys 14 and
cys 17 .
the simulations of the reduced form used the same initial
structure but different charge parameters on the heme .
the
dihedral - based secondary structure classification was based on the
work of hollingsworth et al .
cytochrome c is a small ( 12,000 da ) highly conserved protein that is
found in viruses , plants , humans , etc .
its primary structure is made
of 100 amino acids , though that found in many higher - order organisms
consists of 104 amino acids .
it is an important component in the electron
transport chain and is loosely bound to the inner membrane of mitochondria .
it consists of 5 -helices , 2 -strands , and some turn
structures , which can be detected by infrared spectroscopy and assigned
to specific portions of the protein . in our previous work ,
a two - layer gold surface was used to enhance
the seiras signal of adsorbed cyt c , and we found
that a growth period of 10 min for the second gold layer provided
optimal conditions .
identical surfaces
were prepared for both the seiras and sers to ensure similar experimental
conditions .
as shown in figure s1 ( supporting
information ) , the atomic force microscopy images clearly show
that the initial surface is smooth , with an average roughness of 1.9
nm .
after 10 min , the surface became rough because of the growth of
a second layer of gold nanoparticles into islands and the average
surface roughness increased to 6.9 nm .
such two - layer gold surfaces
have been utilized before by our group in a 2d correlation study of
cytochrome c oxidase and cytochrome c. the motivation of the present work is to
advance the understanding of the interaction between the heme group
and the surrounding protein backbone upon changing the electrode potential .
the two - layer gold surface was modified with 2-mercaptoethanol
( me ) prior to adsorption of cyt c. hydroxyl - terminated
sams have been suggested to weakly affect the conformational characteristics
of cyt c upon adsorption .
moreover , cyclic voltammetry data show that cyt c is successfully adsorbed onto the two - layer gold surface .
the oxidation
peak ( cathodic peak ) at 280 mv and the reduction peak ( anodic peak )
at 203 mv agree well with the previously reported values ( supporting information , figure s2 ) .
the infrared difference spectra of
cyt c have
been studied before using this same methodology and surface architecture
( supporting information , figure s3 ) .
the main infrared
peaks and the corresponding assignments discussed in the text are
summarized in table 1 . as the potential increases ,
the peaks at 1552 and 1658 cm increase in intensity
and one additional peak appears at 1672 cm .
these
peaks are characteristic for oxidized cyt c and correspond
to the amide ii band of a type iii -turn and the amide i band
of a type ii -turn and/or -helix and type iii -turn ,
respectively .
simultaneously , the peak at 1692 cm , corresponding to the amide i band of the type iii -turn
( reduced state ) , decreases in intensity with increasing electrode
potential ( supporting information , figure
s3 ) and exhibits a sigmoid appearance ( supporting
information , figure s4 . ) taken together , the sigmoid appearance
of the 1692 cm intensity clearly indicates that
cyt c undergoes a change from the reduced state to
the oxidized state . for the sers measurement
,
a 532 nm laser is used as the excitation
source to match the q electronic transition of the heme instead of
the b band .
this is preferred because the gold surface is used to
achieve maximum signal enhancement .
the sers spectra show no obvious
changes until + 50 mv vs she , as can be observed in figure 1 .
as the potential increases further , all of the
peaks decrease in intensity except the 10 peak at
1621 cm , which increases .
sigmoid behavior
is also observed for the 1364 cm peak intensity ,
as shown in figure 1 ( inset ) .
again , this sigmoid
curve shows that the redox transition can be followed by the spectral
intensity change .
note that unspecific reorientation of the protein
on the surface will not result in such sigmoid behavior . for detailed raman peak assignment
, we refer
to the work of spiro et al . and supporting information table s1 , which are in
good agreement with the peaks found in our experiment .
the selected
peaks and their corresponding assignment as will be discussed in relation
to the 2d correlation plots are shown in table 2 .
evolution of the sers - active peaks with potential ( from 100
to 500 mv vs she ) for cytochrome c adsorbed to the
2-mercaptoethanol sam - modified two - layer gold substrate .
the black
arrows are used to label the peaks that increase or decrease in intensity
as the potential increases .
( inset : sigmoid behavior of intensity
change of raman peak at 1364 cm . ) overlapping
peaks arising from
different functional groups make it difficult to analyze the infrared
peaks of cyt c , thus hindering accurate band assignments
and reliable determination of the conformational changes of the protein .
second - derivative or fourier deconvolution analyses have been applied
to address this problem , but some of the findings
and conclusions do not agree with the results from x - ray crystallography and nmr studies .
reaction - induced infrared difference spectroscopy also has been
developed for both the bulk and the sam layer of cyt c , and the ability to enhance the spectral resolution was demonstrated
using an enzymatic reaction .
the concept of the
difference spectra suits the basis of 2d correlation spectroscopy ,
which also utilizes an external perturbation ( light , voltage , etc . )
to generate dynamic spectra for analysis .
the use of 2d correlation
spectroscopy spreads the spectrum in the second dimension and facilitates
the deconvolution of overlapping peaks .
thus , it can help enhance
the spectral resolution . although vibrational
features of different molecular origins may make similar contributions
to the spectra in the static case
, they may behave differently ( either
delayed or accelerated ) in the case of a dynamic change .
thus , 2d correlation is an
effective tool for the deconvolution of overlapping peaks .
synchronous ( a ) and asynchronous ( b ) 2d ir correlation
plots from
a seiras analysis of cyt c adsorbed to a two - layer
gold surface .
the synchronous and asynchronous
2d infrared correlation plots
of cyt c were calculated using the 2d shige software
package from the series of one - dimensional ( 1d ) ir spectra generated
with stepwise increased potentials from 100 to + 500 mv ( figure 2 ) .
the peaks that undergo changes in intensity result
in correlation peaks in the 2d plots , whereas the peaks that remain
constant result in no or very small correlation peaks .
the autopeaks
along the diagonal are all positive in a synchronous 2d ir plot ( figure 2a ) and reveal the major peaks of the 1d infrared
spectra . however , these peaks exhibit different degrees of intensity
change during the potential increase . in the synchronous 2d ir plot ,
the intensity of the autopeak at 1692 cm is more
pronounced than that at 1658 cm ( figure 2a ) , suggesting that the influence of the applied
potential on the sequence of peptide groups responsible for the 1692
cm autopeak is greater than that on the sequence
responsible for the 1658 cm autopeak .
examination
of the ir peak assignment leads to the
conclusion that the amide i band of the type ii -turn and/or
-helix ( 1658 cm ) and the amide i band of
the type iii -turn ( 1692 cm ) originate
from different regions of the protein backbone .
thus , different regions
of the protein backbone can be probed by changing the applied potential ,
as revealed by the synchronous 2d ir plot .
cross peaks in the
synchronous 2d ir plot are also indicative of
modes with coupled or related origin . for example , the strong correlation
peak at ( 1552 cm , 1692 cm )
indicates that the spectral features at these two positions may be
related and most likely belong to the same segments of the protein
backbone ( the type iii -turn ; table 1 ) . the negative peak sign ( dark blue ) , however , suggests that the
peak intensities at the two positions change in different directions .
the fact that one of them belongs to the reduced state and
the other
one to the oxidized state clearly suggests that the redox transition
was successfully recorded .
the asynchronous plot ( figure 2b ) provides
additional useful information about the sequential relationship between
the changes in intensity of peaks with different spectral origins ,
thus making it useful for peak deconvolution .
the spectra in figure 2b do not include any autopeaks , which is a distinct
characteristic feature of an asynchronous 2d spectrum .
we observed
a strong negative cross peak at ( 1658 cm , 1692
cm ) and a strong positive cross peak at ( 1692
cm , 1658 cm ) .
application
of noda s rules for analyzing 2d correlation spectra reveals that the peptide groups corresponding
to the amino acids in the type ii -turn and/or -helix
( represented by the peak at 1658 cm ) change their
conformation before those in the type iii -turn ( represented
by the peak at 1692 cm ) . because the signal change
of the amino residues represented by the ir peak at 1692 cm occurred after those represented by the ir peak at 1658 cm , amino acids 1419 and 6770 may reorient to the surface
first followed by those at positions 3238 ( table 1 ) . by comparing existing literature observations with our findings ,
we conclude that the changes
seen in the 2d ir plots can be attributed to conformational changes
within the protein backbone .
prior
to the heterospectral
2d correlation analysis , the 2d raman correlation spectra were calculated
from the series of 1d raman spectra at increasing potentials to probe
the response of the raman - active heme group .
in addition
to the positive autopeaks , most of the cross peaks were also positive ,
which indicates that all of the peak intensities decrease during the
potential increase except for the peak at 1621 cm , which resulted in a negative peak in the 2d spectrum , indicating
an increase in intensity .
this synchronous 2d raman correlation agrees
well with the observations from the 1d raman spectra ( figure 1 ) .
, the raman peaks at 1397 and 1587
cm correspond to vibrational modes of the pyrrole
quarter ring and the c c bond , respectively ( table 2 ) .
the pyrrole quarter ring is located next to the
iron center of the heme , whereas the c c bond is located further
from the heme center . as can be observed from the synchronous 2d raman
correlation spectrum ,
the peak intensity of the 1587 cm autopeak is much more pronounced than that of the autopeak at 1397
cm .
this observation indicates that the correlation
to the change in potential of the (ccm)asym mode ( corresponding to the peak at 1587 cm ) is stronger than that of the (pyrrole quarter
ring ) mode ( corresponding to the peak at 1397 cm ) .
this is in agreement with the literature and our md simulation , suggesting that the heme unit is prone to
reorient ( bend upward or downward ) with the applied potential .
hence
the (ccm)asym mode is , as expected , more sensitive to conformational changes than
the (pyrrole quarter ring ) mode .
the two peripheral propionic
acid groups , which are parts of the heme structure , also can establish
strong interactions with neighboring amino acid residues via hydrogen
bond / electrostatic interaction .
thus , different modes respond differently
to applied potential because of changes in the local environment
. the asynchronous 2d raman correlation plot , in contrast , does not
exhibit significant peaks .
instead , the signals appear within the
noise level ( supporting information , figure
s5 ) .
the lack of significant features is most likely due to the fact
that the corresponding peaks may exhibit frequency shifts in addition
to pure intensity changes .
the
sensitivity to noise of asynchronous correlation analysis is typically
greater than that of synchronous analysis . according to noda ,
the asynchronous
correlation intensity vanishes when all reorientations of the two
dipole momentum transitions occur in phase with the external
perturbation .
hence , all raman - active regions of cyt c are expected to react at the same rate following a potential perturbation
because of the rigid structure of the heme center .
this is consistent
with the conclusion that the bonding distance between the six ligands
with the heme center iron
ion does not change during the redox process , as revealed by recent
x - ray investigations .
synchronous 2d raman correlation plot
from the sers spectra of
cyt c on gold .
thus far , only autologous
ir- or raman - active modes have been correlated .
we introduce also
a heterospectral correlation analysis of the infrared and raman spectra
representing different parts of the protein .
such 2d spectra combining
these two complementary techniques could serve as a visual aid to
help describe more completely the conformational change of cyt c during the redox process .
the synchronous and asynchronous
2d heterospectral correlation plots are again calculated using the
2d shige software , and the result is shown in figure 4 .
the infrared frequency is plotted on the x - axis , and the raman shift on the y - axis , which
makes the coordinate system ( ir peak position , raman peak position )
in the hetero 2d plot .
these 2d heterospectral correlation plots are
no longer symmetrical about the diagonal line , which is in contrast
to the autologous ir ir or raman
the synchronous 2d heterospectral correlation
plot ( figure 4a ) shows that the infrared peak
at 1658 cm forms strong positive peaks with the
main raman peaks and that the strongest peaks are formed with the
raman peaks at 1314 and 1587 cm .
there are also
positive peaks formed under the ir peak at 1552 cm with these raman peaks . for the correlation under the peak at 1692
cm , two negative peaks
are observed , which are
not on the same scale as the positive peaks .
synchronous ( a ) and asynchronous
( b ) 2d heterospectral correlation
plots generated from the seiras and sers dynamic spectra of cyt c on gold .
as mentioned before , an examination of the band assignments
suggests
that the ir peaks at 1692 and 1552 cm both can
be attributed to the type iii -turn , with the 1692 cm peak corresponding to the reduced state and the 1552 cm peak to the oxidized state . during the potential change from 100
to + 500 mv vs she , cyt c undergoes a redox change
from the fully reduced state to the fully oxidized state , which is
reflected well in the synchronous 2d heterospectral correlation plot
by the negative sign of the correlation peak .
the ir peak at 1658
cm corresponding to the type ii -turn and/or
-helix in the oxidized state involves residues 3238 .
these residues can interact directly with the propionate groups of
cyt c and thereby exhibit a strong correlation with
the heme during the redox process .
the different intensities of the
correlation peaks also indicated a large extent of reorientation .
interestingly , the 1692 cm peak , which corresponds
to the amino acids near his 18 that is ligated to the heme iron , resulted
in correlation peaks smaller than those at 1658 cm .
a possible interpretation of these data could be that the strong
coupling between his 18 and the heme prevents the two moieties from
changing configuration and/or reorienting .
in contrast , the residues
associated with the propionate groups have more freedom to move , inducing
more reorientation during the redox process .
the correlation peaks
between the ir peak at 1692 cm ( corresponding
to amino acids 1419 , including his 18 ) with the raman peaks
are either absent or very weak . on the other hand ,
the correlation
peaks between the ir peak at 1658 cm are strong
in intensity and show different peak sign compared to the peaks under
the ir peak at 1692 cm .
this indicates a different
coupling mechanism between the contributing amino acid residues and
the heme center .
we assume that the general rules
developed by noda are valid for all kinds of 2d correlation methods
and can be applied to our data as described in the following .
the
sign of the asynchronous 2d heterospectral correlation peak is positive
at ( 1692 cm , 1587 cm ) , whereas
the sign of the peaks at the same position in the synchronous hetero
2d plot indicates that the sequential relationship for this set of
data must be inverted .
thus , application
of noda s rules to the hetero 2d plots indicates that the residues
represented by the ir peak at 1692 cm would reorient
after the heme , which is represented by the raman peak at 1587 cm .
this analysis allows us to visualize the dynamics
of the redox process of cyt c as follows : the heme
moiety first undergoes a conformational change because it directly
coordinates to the iron ion involved in the redox process .
this is
followed by a reorientation of the his 18 residue that is ligated
to the heme iron .
we also observed two additional peaks in the
asynchronous 2d heterospectral
correlation plot at ( 1692 cm , 1364 cm ) and ( 1692 cm , 1397 cm ) ,
which are absent in the synchronous 2d heterospectral correlation
plot . on the basis of the peak assignment ( supporting
information , table s1 )
, the raman peaks at 1364 and 1397 cm correspond to the stretching modes of (pyrrole
half ring)sym and (pyrrole quarter ring ) , respectively .
on the basis of these findings
, we propose that upon oxidation the
heme undergoes a vibrational change that reflects a change in the
distance between the pyrrole group and his 18 .
in addition to the
described findings , we can show with the help of md calculations that
there is stronger coupling between the heme structure and the protein
backbone ( supporting information , figure
s6 ) .
the broad synchronous peak at ( 1658 cm , 1314
cm ) is split into three separate peaks in the
asynchronous plot at 1624 , 1658 , and 1672 cm because
they are of different origins and display different sequential interactions
with the applied external potential .
again , these ir peaks correspond
to the amide i bands of the extended -strand ( 1624 cm ) , the type ii -turn and/or -helix ( 1658 cm ) , and the type iii -turn ( 1672 cm ) .
a
similar splitting behavior can be observed with the raman peak at
1587 cm , but not with the raman peaks at 1364
and 1397 cm . a closer examination of the raman
vibrational mode assignments ( table 2 ) reveals
that the peaks showing splitting ( 1314 and 1587 cm ) correspond to the pyrrole side chain , while those showing no splitting
( 1364 and 1397 cm ) correspond to pyrrole half - ring
and quarter - ring vibrations , respectively .
this clearly shows that
asynchronous 2d heterospectral correlation analysis can be used to
deconvolute overlapping peaks originating from segments of different
rigidity , molecular environments , etc .
the potential - dependent
response for amino acids 1419 and
6770 , as represented by the infrared peak at 1692 cm , is out of phase with the heme center , as shown from the strong
hetero - asynchronous correlation between the ir peak at 1692 cm and all the raman peaks .
the same conclusions can
be drawn from the strong correlation between the raman peaks at 1314
and 1587 cm and all the infrared peaks in the
amide i region .
this indicates that the conformation change of these
two raman vibrational modes is out of phase with those represented
by the infrared amide i peaks .
the amide ii peak at 1552 cm and the amide i peak at 1692 cm are assigned
to the same amino acids , but they represent different redox states .
that is why they exhibit the same degree of asynchronous change but
in different directions .
the correlation peaks between the ir
peak at 1692 cm and the raman peaks , which are
weak or absent from the synchronous
spectra , increase in intensity in the asynchronous spectra . on the
other hand ,
the correlation peaks between the ir peak at 1658 cm and the raman peaks , which are strong and positive
in the synchronous spectra , disappear or become weak in the asynchronous
spectra .
this could indicate a change in the bond angle between the
two axial ligands his 18 and met 80 as well as a position shift of
the propionate group , as the different correlations may indicate a
change of relative positions .
this is consistent with the findings
of xrd and nmr studies . to confirm our
observations and conclusions ,
molecular dynamics simulations were
also performed . because there are no prominent changes seen in the
overall secondary structure associated with the oxidation , the secondary
structure dynamics for each residue are examined .
the amount of time
each residue spent in a particular secondary structure class was determined
for both the oxidized and reduced forms .
those residues for which
this time varied by at least 5% ( or less if they were close to a previously
monitored residue ) are collected in table s3 ( supporting information ) . the residue assignments from the
2d heterospectral correlation spectroscopic analysis are consistent
with the residues that experienced a change in their secondary structure
assignments or interaction dynamics with the heme propionates ( figure 5 ) .
the simulations show a decreased amount
of time spent in the -turn type iii structure , including residues
1417 ( 7% ) and 6769 ( 7% ) , during oxidation
of the protein , which agrees well with the assigned peaks at 1692
and 1552 cm ( supporting information , table s2 ) .
an unassigned region of residues 5255 took up
the -turn type iii at an increased proportion ( + 10% ) , as shown
in supporting information , table s3 .
this
region was also identified as changing upon oxidation in horse heart
cyt c. in our simulations ,
it is associated with propionate hydrogen bonding / electrostatic interactions
( supporting information , table s4 ) rather
than with direct interaction through his 18 or met 80 , as is the case
with the other two regions .
this is also reflected in the asynchronous
hetero 2d plot shown in figure 4b in which
the helix structure differs from the -turn structure in the
molecular environment .
hence , they can be distinguished by combining
the hetero 2d analysis and md simulation .
the ir peak at 1658
cm is assigned to a -turn
type ii and/or -helix structure and to the two consecutive
turns at residues 3235 and 3538 . both turns are observed during the md simulations , but
the change in secondary structure is very small ( 3% and 6% , respectively )
upon oxidation , which is in good agreement with nmr and x - ray observations .
on the other hand , the turns changed h - bonding dynamics with the heme
( arg 38 ) and established important hydrogen bond interactions with
the regions 1419 and 2123 ( asn 31 ) .
( a ) amino acids with
changed secondary structure dynamics ( orange )
and heme hydrogen bonding ( purple ) based on md simulations .
( b ) amino
acids in the amide i region detected using 2d seiras and associated
with the ir peaks at 1658 cm ( blue ) , 1692 cm ( red ) , and 1624 cm ( yellow ) .
green portions are unmarked , and the heme is shown in gray , oxygen
in red , and nitrogen in blue .
additionally , the distances of the heme and his 18 were also
monitored
in the different oxidation states ( supporting
information , figure s6 ) .
although the average distance changes
only slightly , the smaller charge of the reduced heme center allowed
for more fluctuations , in good agreement with the stronger coupling
observed in the hetero 2d correlation analysis .
we have successfully performed a 2d correlation
analysis upon changing
the redox state of cyt c adsorbed on a two - layer
gold surface .
2d infrared correlation and 2d raman correlation spectroscopies
were performed to enhance spectral resolution and to provide a deeper
understanding of the sequential changes occurring in the various portions
of the protein . specifically , we have performed three types
of correlation analysis ,
namely , autologous ir vs ir , raman vs raman , and heterologous ir vs
raman .
our data indicate that different segments of the protein respond
differently to changes in the electrode potential and reorient sequentially .
for example , it is found that the heme groups reoriented and changed
conformation / interactions prior to the rest of the protein backbone .
some features that are not readily observed in the 1d spectra can
be distinguished using a 2d correlation analysis .
peaks arising from
different spectral origins or different molecular environments can
be differentiated by their dynamic change under an external perturbation .
thus , the oxidation of cytochrome c can be readily
monitored using 2d correlation analysis .
there is also a good agreement
between the results of the 2d analysis and the molecular dynamics
simulations , e.g. , the distance between the his 18 and the heme is
reflected in the 2d correlation spectra and reveals the conformation
change of the protein .
these findings are remarkable because
they show a clear fragmentation
of sequential order , which indicates that the conformational changes
induced by the oxidation occurred at different rates for different
parts of the protein backbone .
the example of a well - studied system ,
such as cyt c , has effectively demonstrated the potential
of 2d heterospectral correlation spectroscopy for further applications
on more complex membrane redox proteins . | ### Summary:
: the
heme protein cytochrome c adsorbed to a two - layer
gold surface modified with a self - assembled monolayer of 2-mercaptoethanol
was analyzed using a two - dimensional ( 2d ) heterospectral correlation
analysis that combined surface - enhanced infrared absorption spectroscopy
( seiras ) and surface - enhanced raman spectroscopy ( sers ) .
stepwise
increasing electric potentials were applied to alter the redox state
of the protein and to induce conformational changes within the protein
backbone .
we demonstrate herein that 2d heterospectral correlation
analysis is a particularly suitable and useful technique for the study
of heme - containing proteins as the two spectroscopies address different
portions of the protein .
thus , by correlating sers and seiras data
in a 2d plot , we can obtain a deeper understanding of the conformational
changes occurring at the redox center and in the supporting protein
backbone during the electron transfer process .
the correlation analyses
are complemented by molecular dynamics calculations to explore the
intramolecular interactions . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: dm is a heterogeneous chronic metabolic disorder principally characterized by persistent hyperglycemia resulting from defects in insulin action and/or insulin secretion.1 it affects more than 171 million individuals worldwide and has reached epidemic status.2 dm results from a malfunction of insulin - dependent glucose homeostasis .
classically , they present a triad of symptoms including polyuria , polyphagia , and polydipsia .
these are the direct result of hyperglycemia and osmotic imbalance.3 the disease is characterized by an increased susceptibility to infection , poor wound healing , and increased morbidity and mortality associated with disease progression .
type 1 , insulin - dependent dm is characterized by abrupt onset at any age , destruction of 80 - 90% of the pancreatic islet cells that produce insulin , and dependence on exogenous insulin to prevent ketosis and preserve life .
about 15% of diabetics are type 1.4 long - term poor glycemic control in type 1 dm patients leads to macrovascular and microvascular complications . periodontal disease has been reported as the sixth complication of diabetes along with neuropathy , nephropathy , retinopathy , and micro and macrovascular diseases.5 periodontal diseases are a group of inflammatory diseases that affect the periodontal attachment apparatus ( gingiva , periodontal ligament , alveolar bone , and cementum ) .
it is characterized by redness and edema of gingival tissue , bleeding on provocation , changes in contour and presence of calculus or plaque with no radiographic evidence of crystal bone loss.6 periodontitis is defined as an inflammatory disease of the supporting tissues of the teeth caused by specific microorganisms , resulting in progressive destruction of the periodontal ligament and alveolar bone with pocket formation , recession or both .
the clinical feature that distinguishes periodontitis from gingivitis is the presence of clinically detectable attachment loss .
this is often accompanied by periodontal pocket formation and changes in the density and height of subjacent alveolar bone.7 in type 1 dm chronic hyperglycemia leads to formation of biologically active glycated proteins and lipids that promote inflammatory responses.8,9 long - term poor control of dm in type 1 patients leads to microvascular damage of the periodontium , alteration in composition of gingival crevicular fluid , host bacterial flora of the gingiva and impaired healing response of periodontium .
increased levels of inflammatory markers such as c - reactive protein , tumor necrosis factor- , interleukin-6 ( il-6 ) , il-1 , prostaglandin e2 , and il-10 observed in patients with diabetes may play a role in periodontal damage.10 the present study was designed to investigate the relationship between severity of periodontal disease and glycemic control in patients with type 1 dm .
fifty patients were recruited from the department of medicine , people s college of medical sciences and research centre .
inclusion criteria were : age between 12 and 25 years and with a diagnosis of type 1 dm for more than 3 months duration .
patients were excluded from the study if they were non - type 1 diabetics , undergoing active orthodontic treatment , patients with any chronic inflammatory diseases and on long - term medications that could influence the studied parameters such as antibiotics and antiepileptic immunosuppressive drugs .
the individuals were classified according to their glycemic control as good ( glycated hemoglobin [ hba1c ] 7)11 group a , fair ( hba1c = 7 - 8)11 group b , and poor ( hba1c >
the periodontal status was examined by recording the following parameters : plaque index ( pi ) ; silness and loe ( 1964)12 , gingival index ( gi ) ; loe and silness ( 1963)12 , probing pocket depth ( ppd)13 and clinical attachment level ( cal)13 after adjusting for age , gender , frequency of prior dental visits and dental examiner .
dental plaque is a soft , non - mineralized deposit that forms on the tooth surface .
gi assessed the severity of gingivitis , by examining qualitative changes of gingival soft tissue .
a blunt instrument such as periodontal probe was used to assess the bleeding potential of tissues .
ppd and cal measured the distance from the gingival margin to the base of gingival sulcus and distance from cementoenamel junction to base of sulcus respectively.12,13 ppd and cal were obtained from six exploratory points for each tooth with a calibrated north carolina probe , by a single examiner .
the pockets were classified into two groups according to the depth : medium pockets with depth 4 - 5 mm and deep pockets with depth > 6 mm .
the cal was classified into three groups : cal < 2 mm ( mild periodontitis ) , cal 3 - 4 mm ( moderate periodontitis ) , cal 5 mm ( severe periodontitis).13
the subjects were divided into three groups depending on the hba1c levels : good ( hba1c 7)11 group a , fair
the number and percentage of subjects in each group were group a - 15 ( 30% ) , group b - 16 ( 32% ) , and group c - 19 ( 38% ) ( table 1 ) . the number and percentage of males and females in the study group were males - 32 ( 64% ) , females - 18 ( 36% ) .
the mean and standard deviation of periodontal parameters pi , gi , ppd , and cal in group a ( hba1c 7 ) were 2.93 0.59 , 3.33 0.48 , 1.25 0.20 , and 1.25 0.34 , respectively .
the mean and standard deviation of periodontal parameters pi , gi , ppd , and cal in group b ( hba1c = 7 - 8 ) were 3.81 0.75 , 4.43 0.62 , 1.82 0.45 , and 1.43 0.33 , respectively . the mean and standard deviation of periodontal parameters in group c ( hba1c > 8) were 5.31 0.20 , 6.15 1.38 , 2.39 0.18 , and 2.01 0.29 , respectively ( table 2 ) .
comparison of periodontal parameters among the three groups was done by applying the anova test .
number and percentage of individuals in each group . mean and standard deviation of periodontal parameters in group a , b , c. on comparison of the periodontal parameters pi , gi , ppd , and cal between group a , b , and c the values
were found to be significantly higher ( p < 0.05 ) in group c followed by group b and lowest in group a ( tables 3 - 5 ) . the results of this study showed that there is increased severity of periodontal disease with poor glycemic control in type 1 diabetics .
comparison between groups a and b. comparison between groups b and c. comparison between groups a and c.
in this study , the patients with poor glycemic control ( group c ) had deeper pockets and more attachment loss which was in accordance with the findings of studies conducted by llambs et al .
2002,16 and seppl et al . 1993 , 1997.17,18 tervonen and oliver19 demonstrated this in a cross - sectional study into the association between long - term diabetic control and periodontal status .
diabetics were assessed using hba1c and for plaque , calculus , probing depth , and attachment loss . based on their control of blood glucose levels , they were grouped into good control ,
it was found that the prevalence of severe attachment loss increased with decreasing control of diabetes .
this study found that 10% of well controlled and 27% of poorly controlled diabetics had loss of attachment > 5 mm.19 these findings have been confirmed by other studies - both cross - sectional20 and longitudinal.17,21 the present study showed that subjects with poor glycemic control harbored more plaque and had more severe gingival inflammation as evident by the higher scores of gi and pi .
200722 who found higher pi scores and greater gingival inflammation in a large cohort of type 1 diabetics as compared to non - diabetic controls .
high blood glucose sustained over time appears to give rise to a situation of chronic inflammatory mediator secretion , and thus to an exaggerated periodontal response .
however , from the opposite perspective , it could be postulated that the severity of pd could affect dm control despite adequate integral treatment and patient cooperation.15
periodontal diseases can be prevented in susceptible individuals at an early stage23,24 if regular oral screenings and periodontal treatment programs are considered as a standard of care for young patients with type 1 diabetes . | ### Summary:
: background : both diabetes mellitus ( dm ) and periodontitis are chronic diseases affecting large number of the population worldwide .
changes in human behavior and lifestyle over the last century have resulted in a dramatic increase in the incidence of diabetes in the world . this study was designed to evaluate the relationship between severity of periodontal disease and control of diabetes ( glycated hemoglobin [ hba1c ] ) in patients with type 1 dm in a hospital based study.materials and methods : fifty patients ( n = 50 ) with type 1 diabetes were enrolled in the study .
they were divided into three groups based on the degree of glycemic control by measuring hba1c levels as : good ( hba1c 7 ) group a , fair ( hba1c = 7 - 8 ) group b and poor ( hba1c > 8) group c. all enrolled patients underwent detailed history and dental checkup .
evaluation for periodontal disease was done by measuring dental plaque ( plaque index ) , inflammation of gums ( gingival index ) , probing pocket depth ( ppd ) , and clinical attachment level.results:type 1 diabetics with poor glycemic control had increased gingival inflammation ( p < 0.05 ) , more dental plaque ( p < 0.05 ) , increased ppds ( p < 0.05 ) and attachment loss ( p < 0.05 ) as compared to those with fair and good glycemic control , respectively.conclusion:severity of periodontal disease increases with poor glycemic control in patients with type 1 dm . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: three laboratory colonies of p.
sergenti were used1 ) tu originating from sanliurfa , turkey ; 2 ) is originating from amnun , israel ; and 3 ) isg derived from is females artificially infected by ps .
sand flies were maintained under standard conditions as previously described by volf and volfova ( 2011 ) .
leishmania tropica su23 ( mhom / tr/98/hm ) was maintained at 23c on m199 medium ( sigma - aldrich , st .
louis , mo ) supplemented with 20% foetal calf serum ( gibco , life technologies , carlsbad , ca ) , 1% bme vitamins ( sigma - aldrich ) , 2% filtered human urine , amikacin ( 250 mg / ml ) , and gentamicin ( 80 mg / ml ) .
sand fly females ( 47 d old ) were fed through a chick - skin membrane on heat - inactivated rabbit blood containing 1 10 promastigotes / ml . this infective dose corresponds to < 1,000 parasites per female , as bloodmeal volumes taken by various sand fly species ranged from 0.53 to 0.91 l ( pruzinova et al .
. moreover , promastigote - initiated infections are fully comparable with amastigote - initiated infections ( freitas et al . 2012 ) .
blood - fed females were maintained at 26c and dissected on days 2 and 710 postinfection ( p.i . ) , and their guts were microscopically checked for the presence and localization of leishmania promastigotes .
( 2008)weak ( 1100 promastigotes per gut ) , moderate ( 1001,000 promastigotes per gut ) , and heavy ( > 1,000 promastigotes per gut ) .
the experimental infection was repeated two ( tu is ) or three times ( is isg ) .
data were statistically evaluated by means of the test using statistica 12.0 software ( statsoft ) .
three laboratory colonies of p.
sergenti were used1 ) tu originating from sanliurfa , turkey ; 2 ) is originating from amnun , israel ; and 3 ) isg derived from is females artificially infected by ps .
sand flies were maintained under standard conditions as previously described by volf and volfova ( 2011 ) .
leishmania tropica su23 ( mhom / tr/98/hm ) was maintained at 23c on m199 medium ( sigma - aldrich , st .
louis , mo ) supplemented with 20% foetal calf serum ( gibco , life technologies , carlsbad , ca ) , 1% bme vitamins ( sigma - aldrich ) , 2% filtered human urine , amikacin ( 250 mg / ml ) , and gentamicin ( 80 mg / ml ) .
sand fly females ( 47 d old ) were fed through a chick - skin membrane on heat - inactivated rabbit blood containing 1 10 promastigotes / ml . this infective dose corresponds to < 1,000 parasites per female , as bloodmeal volumes taken by various sand fly species ranged from 0.53 to 0.91 l ( pruzinova et al .
. moreover , promastigote - initiated infections are fully comparable with amastigote - initiated infections ( freitas et al . 2012 ) .
blood - fed females were maintained at 26c and dissected on days 2 and 710 postinfection ( p.i . ) , and their guts were microscopically checked for the presence and localization of leishmania promastigotes .
( 2008)weak ( 1100 promastigotes per gut ) , moderate ( 1001,000 promastigotes per gut ) , and heavy ( > 1,000 promastigotes per gut ) .
the experimental infection was repeated two ( tu is ) or three times ( is isg ) .
data were statistically evaluated by means of the test using statistica 12.0 software ( statsoft ) .
three laboratory colonies of p.
sergenti were used1 ) tu originating from sanliurfa , turkey ; 2 ) is originating from amnun , israel ; and 3 ) isg derived from is females artificially infected by ps .
sand flies were maintained under standard conditions as previously described by volf and volfova ( 2011 ) .
leishmania tropica su23 ( mhom / tr/98/hm ) was maintained at 23c on m199 medium ( sigma - aldrich , st .
louis , mo ) supplemented with 20% foetal calf serum ( gibco , life technologies , carlsbad , ca ) , 1% bme vitamins ( sigma - aldrich ) , 2% filtered human urine , amikacin ( 250 mg / ml ) , and gentamicin ( 80 mg / ml ) .
sand fly females ( 47 d old ) were fed through a chick - skin membrane on heat - inactivated rabbit blood containing 1 10 promastigotes / ml .
this infective dose corresponds to < 1,000 parasites per female , as bloodmeal volumes taken by various sand fly species ranged from 0.53 to 0.91 l ( pruzinova et al .
moreover , promastigote - initiated infections are fully comparable with amastigote - initiated infections ( freitas et al .
blood - fed females were maintained at 26c and dissected on days 2 and 710 postinfection ( p.i . ) , and their guts were microscopically checked for the presence and localization of leishmania promastigotes .
( 2008)weak ( 1100 promastigotes per gut ) , moderate ( 1001,000 promastigotes per gut ) , and heavy ( > 1,000 promastigotes per gut ) .
the experimental infection was repeated two ( tu is ) or three times ( is isg ) .
data were statistically evaluated by means of the test using statistica 12.0 software ( statsoft ) .
in the first series of experiments , the development of l. tropica was compared in p. sergenti tu and is .
parasites developed well in the females of both colonies tested . in early - stage infections ( day 2 p.i . ) , all dissected females were infected , with a slightly higher proportion of heavy infections found in tu females ( = 6 ; df = 2 ; p = 0.05 ; fig .
, the infection rates and intensities of infection were the same in tu and is females ( = 0.316 ; df = 1 ; p = 0.574 and = 4.747 ; df = 3 ; p = 0.191 ; respectively ) . in both tested groups ,
heavy late - stage infections with anterior migration of leishmania promastigotes , presence of metacyclic forms , and colonization of the stomodeal valve were observed from day 7 ( fig .
1.the development of l. tropica in p. sergenti : ( a ) comparison of two p. sergenti colonies originating from turkey ( tu ) and israel ( is ) ; ( b ) comparison of a colony infected by the gregarine ps .
intensities of the leishmania infection were estimated as light ( < 100 promastigotes per gut)white bar , moderate ( 1001,000 promastigotes per gut)striped bar , and heavy ( > 1000 promastigotes per gut)black bar
. numbers above each bar indicate the number of dissected females .
the development of l. tropica in p. sergenti : ( a ) comparison of two p. sergenti colonies originating from turkey ( tu ) and israel ( is ) ; ( b ) comparison of a colony infected by the gregarine ps .
intensities of the leishmania infection were estimated as light ( < 100 promastigotes per gut)white bar , moderate ( 1001,000 promastigotes per gut)striped bar , and heavy ( > 1000 promastigotes per gut)black bar .
next , we performed an additional series of experiments comparing is and isg females . in mosquitoes ,
the gregarine ascogregarina culicis has been implicated in maintenance of the chikungunya virus ( mourya et al .
no significant differences in infection parameters were detected between is and isg females on any day p.i . on day 2 , infection rates were 100% and were of similar intensities , with heavy infections observed in a majority of females of both colonies ( = 0.870 ; df = 2 ; p = 0.647 ; fig 1b ) . in the late development stage ( day 710 p.i . ) , the infection rate was > 60% in both p.
sergenti groups ( 76% and 64% for is and isg , respectively ; = 1.155 ; df = 1 ; p = 0.283 ) , intensities of infection were comparable ( = 1.407 ; df = 3 ; p = 0.704 ) , and heavy late - stage infections with colonization of the stomodeal valve were observed in 50% of infected females ( fig .
sergenti did not have any apparent effect on the development of l. tropica in p. sergenti in our experimental settings . in summary
, we demonstrate the ability of l. tropica to develop equally well in two p. sergenti colonies that represent the two different branches previously postulated by depaquit et al .
our results support recent findings on the similarity of cytochrome b sequences in specimens from turkey and israel ( dvorak et al .
2011 ) and also correspond with the ability of p. sergenti colonies originating from turkey and israel to cross breed with no negative effect on their offspring ( dvorak et al .
it seems that the different geographical origin of p. sergenti tested here is not reflected by different susceptibility to l. tropica .
this finding on p. sergenti corresponds with results on leishmania
donovani vectors : two populations of phlebotomus
orientalis parrot , 1936 from endemic and nonendemic areas in ethiopia were equally susceptible to l. donovani , and the authors ( seblova et al .
2013 ) concluded that factors other than the vector competence of p. orientalis play a role in the epidemiology of l. donovani in ethiopia .
similarly , differences in the distribution of l. tropica and its main vector p. sergenti may be rather attributed to factors other than the different vector competence of various p. sergenti populations . | ### Summary:
: phlebotomus sergenti parrot , 1917 is the main vector of leishmania tropica ; however , its broad geographical range and molecular heterogeneity suggest possible variability in vector competence .
we infected laboratory - reared p. sergenti originating from turkey and israel to compare their susceptibility to l. tropica . in both tested groups , heavy late - stage infections with the presence of metacyclic forms and colonization of the stomodeal valve were observed .
the similar development of leishmania in both sand fly colonies indicates that the different geographical origin of p. sergenti is not reflected by a different vector competence to l. tropica .
additionally , we tested the effect of the gregarine psychodiella sergenti on l. tropica coinfections ; no apparent differences were found between p. sergenti infected or not infected by gregarines . |
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: in january 2007 , a 74-year - old male was admitted to our hospital for treatment of adenoma - like dysplastic lesion ( alm ) .
four years before admission , he had been diagnosed with ulcerative colitis ( uc ) endoscopically and histologically ; there were extensive colonic lesions .
he had been treated with 3,000 mg of oral salazosulphapyridine and had attended follow - up colonoscopic examination every year .
endoscopic findings revealed pseudopolyps and scar formations through the entire colon and a protruded lesion with an approximate size of 3 cm at the splenic flexure surrounded by pseudopolyps ( fig .
histological findings of the biopsy specimen from this lesion on previous endoscopic examination revealed tubular adenoma .
additionally , remnant neoplastic tissue was treated with argon plasma coagulation ( apc ) ( fig .
patients with long - standing or extensive uc are at increased risk of developing cancer [ 1 , 2 ] . therefore , colonoscopic surveillance in patients with long - standing uc is highly recommended .
the main objective of surveillance colonoscopy in uc is to detect neoplasia at a surgically curative and preferably preinvasive stage .
in addition , endoscopic differentiation of an alm and dysplasia - associated lesional mass in chronic uc ( cuc ) is a critical issue , because alm can be indicated for endoscopic treatment [ 3 , 4 , 5 ]
. however , mucosal and submucosal fibrosis induced by long - standing inflammatory activity in cuc makes it difficult to perform endoscopic resection of alm .
reported the effectiveness of a combined endoscopic mucosal resection and cap - assisted submucosal dissection technique for adenoma - like mass in cuc .
exactly , esd - assisted emr technique should be a promising treatment for alm in cuc to avoid unnecessary surgical treatment .
on the other hand , we sometimes encountered difficult cases of alm in patients with cuc even by esd - assisted emr technique .
we herein presented an uc patient with alm successfully treated by the combination of endoscopic resection and heat ablation therapy .
alm observed in this case was classified into sessile type ( is ) according to the paris workshop guidelines for gross morphological classification of neoplastic colorectal lesion in uc .
in addition , the patient was of old age and had a medical history of chemoradiotherapy for pharynx and pulmonary cancer .
therefore , we selected endoscopic treatment to avoid surgery despite the size of the tumor .
however , the lateral margin of this tumor was unclear because of surrounding pseudopolyps , and lifting sign was also poor . taken together , we performed the combination of endoscopic resection and heat ablation therapy with apc .
as a result , no local recurrence of alm was observed 15 months after the combination therapy .
whether or not the possibility of local recurrence after ablation therapy in addition to endoscopic resection performed in this case is higher compared to esd - assisted emr technique remains unclear . in this regard , surveillance colonoscopy in patients with cuc having experienced endoscopic treatment for their colonic tumors should be performed routinely for detecting early local recurrence of colonic tumor and newly emerging colonic lesions either after ablation therapy or esd - assisted emr . in conclusion , we report a uc patient with alm successfully removed by the combination of endoscopic resection and heat ablation therapy with apc .
the development of endoscopy enables us to find neoplastic lesions in cuc which can be indicated for endosocopic therapy .
thus , gastroenterologists should take various therapeutic options into consideration when treating cases of neoplastic lesions in cuc . | ### Summary:
: in january 2007 , a 74-year - old male was admitted to our hospital for treatment of an adenoma - like dysplastic lesion ( alm ) . he had a four - year history of ulcerative colitis .
endoscopic findings revealed that a protruded lesion with an approximate size of 3 cm at the splenic flexure was surrounded by pseudopolyps .
lifting of the tumor was poor despite injection of normal saline around it .
therefore , the combination of endoscopic resection and heat ablation therapy with argon plasma coagulation was performed .
histopathological examination of the resected specimen showed tubular adenoma with high - grade atypia .
endoscopic examination 15 months after this treatment revealed no occurrence of alm .
whether or not there is a possibility of local recurrence after ablation therapy in addition to endoscopic resection performed in this case remains unclear .
however , this endoscopic therapy is a promising option for alm in chronic ulcerative colitis . |
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: tendons are fibrous connective tissues connecting muscle to bone to facilitate joint movement and to maintain skeletal stability .
tendons are mainly composed of extracellular matrix ( ecm ) containing 68% water , 30% collagen , and 2% elastin , in which a very low density of tenocytes are embedded . as the main cell population in tendons , tenocytes are responsible for synthesizing and maintaining tendon ecm . tenocytes were long considered as the only cell type in tendons .
tendon - derived stem cells ( tscs ) were first discovered in 2007 in the tendons of many species , including humans , mice , rats , and rabbits . like other stem cells ,
tscs have self - renewal capacity with multi - differentiation potential to change into tenocytes , chondrocytes , osteocytes , and adipocytes under specific conditions . due to being subjected to large mechanical loads , tendons are easily injured .
after tendon injuries , patients often have a long , complex healing process with the formation of a fibrotic scar . as a result ,
the pattern of collagen fibers and fibrils are changed in tendons with fibrotic scarring ; therefore , these tendons have inferior mechanical strength compared to normal tendon tissue , resulting in significant dysfunction and disability .
recently , many laboratory studies have shown promising outcomes of tendon repair treated with stem cells [ 710 ] because of various proliferation and differentiation advantages of using stem cells . moreover
, many studies demonstrated that tscs not only retained multi - differentiation potentials like other stem cells , but also were more prone to transform into tenocytes than other stem cells .
therefore , tscs might become a novel cell source for tissue engineering , attracting increasing attention from experimental and clinical researchers .
the self - renewal capacity and differentiation of stem cells are influenced by different environments , such as ecm composition , ph value , oxygen tension , and mechanical loading .
however , in the expansion process tscs are predisposed to differentiate quickly , causing stemness loss under regular culture conditions of 95% air and 5% co2 . in vivo , tendons are collagen - rich , avascular structures ; therefore , the oxygen level in tendons is relatively lower than in vascular - rich organs and tissues
a previous study has demonstrated that tscs could better maintain their stemness under hypoxic conditions .
therefore , we performed the present study to investigate the effect of different hypoxic conditions in self - renewal capacity and differentiation of human tscs ( htscs ) .
all tendon tissues were collected from supraspinatus tendons of 6 young adult donors , with approval from the research ethics committee of the second affiliated hospital and yuying children s hospital of wenzhou medical university ( wenzhou , china ) .
htscs isolation was performed according to the method previously introduced by lee et al . .
a condition of 37c with 5% co2 in a humidified incubator was applied for cell culture , as previously described ( 13 ) .
the hypoxic and normoxic culture conditions was controlled according to the procedure described by zhang et al . .
hypoxic conditions ( 0.5% , 5% , 10% o2 ) in the present study were achieved using a dedicated tri - gas incubator .
a regular tissue culture incubator was used to maintain normoxic culture conditions via feeding 95% air and 5% co2 . during all experiments , oxygen concentration in all incubators
therefore , in the present study , htscs cultured under normoxic culture conditions were divided into a control group ( 20% o2 group ) , and htscs cultured under the other 3 conditions were divided into 3 experimental groups ( 0.5% , 5% , and 10% o2 ) .
htscs were seeded into a culture dish at a seeding density of 50 cells / cm for 14 days .
subsequently , all cells were stained using pbs method for counting cell colonies . colonies of more than 50 cells under a microscope were counted .
we determined cell proliferation using the cell counting kit-8 ( cck-8 ) ( dojindo , kumamoto , japan ) at days 1 , 2 , 6 , and 12 after seeding , as previously described .
total rna extraction from htscs was conducted using trizol reagent ( invitrogen , carlsbad , ca ) .
we reverse - transcribed 1 g rna to synthesize first - strand cdna with the revertaid rt - pcr system ( fermentas , pittsburgh , pa ) .
qrt - pcr was carried out using the maxima sybr green qpcr master mix ( applied biosystems , carlsbad , ca ) in a chromo 4 detector ( mj research ) following the manufacturer s instructions .
we synthesized gene - specific primers for nucleostemin ( ns ) , nanog , oct-4 , ssea-4 , runx-2 , ppar- , and sox-9 based on previously published sequences ( 16 ) .
the adipogenic , osteogenic , and chondrogenic differentiation capabilities of htscs in hypoxic and normoxic culture conditions were evaluated as previously described . to perform differentiation potential assay , cells were cultured for up to 14 days in 3 different mediums adipogenic induction medium ( dmem , 20% fbs , 100 mm indomethacin , and 0.5 mm isobutylmethylxanthine ) , osteogenic induction medium ( dmem - low glucose , 20% fbs , 50mg / ml ascorbic 2-phosphate , 100 mg / ml sodium pyruvate , and 50 mg / ml insulin - transferrin - selenious acid mix ) , and chondrogenic induction medium ( dmem , 20% fbs , 0.2 mm ascorbic 2-phosphate , 10 mm glycerol 2-phosphate ) according to the manufacturer s instructions .
western blotting was performed to examine nanog , ns , oct-4 , and ssea-4 protein . after being cultured under hypoxic or normoxic conditions for 3 days ,
the protein was separated by 12% sds - page , transferred to pvdf membranes , and subsequently blocked in 5% fat - free milk for 2 h , following by incubation with primary antibodies at 4c overnight .
secondary antibody ( dako , carpentaria , ca ) conjugated with horseradish peroxidase was then applied .
finally , protein bands were detected with chemiluminescence ( beyotime , shanghai , china ) .
all experiments were repeated 3 times . statistical analysis , including one - way analysis of variance ( anova ) , t test , and tukey s hsd post hoc test , was conducted using graphpad prism 5 software ( graphpad software inc . , la jolla , ca ) .
all tendon tissues were collected from supraspinatus tendons of 6 young adult donors , with approval from the research ethics committee of the second affiliated hospital and yuying children s hospital of wenzhou medical university ( wenzhou , china ) .
htscs isolation was performed according to the method previously introduced by lee et al . .
a condition of 37c with 5% co2 in a humidified incubator was applied for cell culture , as previously described ( 13 ) .
the hypoxic and normoxic culture conditions was controlled according to the procedure described by zhang et al . .
hypoxic conditions ( 0.5% , 5% , 10% o2 ) in the present study were achieved using a dedicated tri - gas incubator . a regular tissue culture incubator was used to maintain normoxic culture conditions via feeding 95% air and 5% co2 . during all experiments , oxygen concentration in all incubators
therefore , in the present study , htscs cultured under normoxic culture conditions were divided into a control group ( 20% o2 group ) , and htscs cultured under the other 3 conditions were divided into 3 experimental groups ( 0.5% , 5% , and 10% o2 ) .
htscs were seeded into a culture dish at a seeding density of 50 cells / cm for 14 days .
subsequently , all cells were stained using pbs method for counting cell colonies . colonies of more than 50 cells under a microscope were counted .
we determined cell proliferation using the cell counting kit-8 ( cck-8 ) ( dojindo , kumamoto , japan ) at days 1 , 2 , 6 , and 12 after seeding , as previously described .
total rna extraction from htscs was conducted using trizol reagent ( invitrogen , carlsbad , ca ) .
we reverse - transcribed 1 g rna to synthesize first - strand cdna with the revertaid rt - pcr system ( fermentas , pittsburgh , pa ) .
qrt - pcr was carried out using the maxima sybr green qpcr master mix ( applied biosystems , carlsbad , ca ) in a chromo 4 detector ( mj research ) following the manufacturer s instructions .
we synthesized gene - specific primers for nucleostemin ( ns ) , nanog , oct-4 , ssea-4 , runx-2 , ppar- , and sox-9 based on previously published sequences ( 16 ) .
the adipogenic , osteogenic , and chondrogenic differentiation capabilities of htscs in hypoxic and normoxic culture conditions were evaluated as previously described . to perform differentiation potential assay , cells were cultured for up to 14 days in 3 different mediums adipogenic induction medium ( dmem , 20% fbs , 100 mm indomethacin , and 0.5 mm isobutylmethylxanthine ) , osteogenic induction medium ( dmem - low glucose , 20% fbs , 50mg / ml ascorbic 2-phosphate , 100 mg / ml sodium pyruvate , and 50 mg / ml insulin - transferrin - selenious acid mix ) , and chondrogenic induction medium ( dmem , 20% fbs , 0.2 mm ascorbic 2-phosphate , 10 mm glycerol 2-phosphate ) according to the manufacturer s instructions .
western blotting was performed to examine nanog , ns , oct-4 , and ssea-4 protein . after being cultured under hypoxic or normoxic conditions for 3 days ,
the protein was separated by 12% sds - page , transferred to pvdf membranes , and subsequently blocked in 5% fat - free milk for 2 h , following by incubation with primary antibodies at 4c overnight .
secondary antibody ( dako , carpentaria , ca ) conjugated with horseradish peroxidase was then applied .
finally , protein bands were detected with chemiluminescence ( beyotime , shanghai , china ) .
statistical analysis , including one - way analysis of variance ( anova ) , t test , and tukey s hsd post hoc test , was conducted using graphpad prism 5 software ( graphpad software inc . , la jolla , ca ) .
we first assessed the effects of hypoxia treatment on self - renewal capacity of htscs .
similar numbers of htscs were cultured in 0.5% , 5% , 10% , and 20% o2 cultures .
we found that 5% o2 culture is more beneficial for the self - renewal of htscs than the other 3 cultures , with larger colony sizes and numbers ( figure 1a1c ) .
in addition , proliferation of htscs in 5% , 10% , and 20% o2 cultures increased after seeding ( figure 1d ) .
the number of cells in the concentration of 5% of o2 was higher than that in other culture ; however , self - renewal capacity of htscs in 0.5% o2 was inhibited .
then , we examined the stemness of htscs using qrt - pcr and western blot analysis .
we found that the expression levels of stem cell markers , including ns , nanog , oct-4 , and ssea-4 , were highest in 0.5% o2 culture .
furthermore , the environment with 0.5% o2 or 20% o2 inhibited the stemness of htscs ( figure 2 ) .
finally , the multi - differentiation potential of htscs was determined through the analysis of ppar- ( adipogenic marker ) , runx-2 ( osteogenic marker ) , and sox-9 ( chondrogenic marker ) .
oil red o ( millipore ) staining for adipogenesis , alizarin red solution ( millipore ) for osteogenesis , and alcian blue ( millipore ) staining for chondrogenesis were used . during the 14-day period of differentiation ,
htscs cultured in 20% o2 exhibited significantly higher expression of the 3 markers ( ppar- , sox-9 , and runx-2 ) , suggesting that the 20% o2 environment promoted the differentiation of htscs ( figure 3 ) .
surgical options for tendon injuries during clinical therapy are limited , with different implantations , including autografts and allografts .
however , instead of complete regeneration , tendon healing after surgical treatment is accompanied by poor results , with scarring formation and adhesion , leading to partial tendon dysfunction .
an increasing number of investigators are engaged in fundamental basic science studies aimed at understanding the exact mechanism of tendon injury and healing .
the identification of tsc started a new epoch in understanding the pathology of and developing novel strategies for tendon injury . increasing animal studies
the present study is the first to investigate the effect of different hypoxic concentrations on htscs .
our findings suggest that environmental oxygen is an important factor for the growth and proliferation of htscs , and that a hypoxic environment is promotes tscs to form effective engineering tissue for injured tendon repair .
moreover , hypoxia should be kept within a certain range , because concentrations of o2 that are too low influence the capacity of htscs .
our results also indicated that the hypoxic condition of 5% o2 can improve tscs self - renewal to achieve sufficient numbers of tscs necessary for tissue engineering .
larger numbers of stem cells are more competitive for tissue repair or regeneration when using stem cells to treat tendon injury .
many studies have demonstrated the potent suppressing effect of hypoxia on mitochondrial oxidation and promoting stemness of several stem cell types [ 2224 ] .
the mitochondrial oxidative metabolism status has been indicated to play an important role in stem cells .
a recent study reported that it was easier to induce mouse embryonic fibroblasts to transform into pluripotent stem cells ( ipscs ) under hypoxic conditions .
some undifferentiated stem cells with lower levels of mitochondrial mass , such as ipscs , and bone marrow mesenchymal stem cells ( bmscs ) , were reported to utilize non - oxidative glycolysis for energy [ 2729 ] .
lavrentieva et al . reported that hypoxia promotes self - renewal of human mesenchymal stem cells ( mscs ) compared with normoxic condition .
. indicated that rat mscs cultured in a hypoxic condition of 5% o2 produced more bone formation than those cultured in a normoxic condition of 20% o2 .
first , the medium using plastic dishes for htscs might have a role in promoting differentiation cell .
second , we grew the htscs in 2d culture , which is not consistent with cells in vivo .
moreover , htscs lacked mechanical loading , which is an important factor for tendons due to muscle - bone force - transmission function .
finally , the molecular mechanism was not investigated , and this needs to be determined in future work .
in summary , hypoxic culture encouraged self - renewal capacity of htscs , but inhibited their multi - differentiation potential , compared to normoxic condition of culture .
future studies investigating the mechanism by which tscs function under low - oxygen conditions are required . | ### Summary:
: backgroundhypoxic conditions play roles in functioning of human tendon - derived stem cells ( htscs ) . the goal of this study was to investigate the effect of various hypoxic conditions in self - renewal capacity and differentiation of tscs.material/methodshtscs was obtain from supraspinatus tendon donors .
colony formation and cell proliferation assay were used to assess the self - renewal of htscs .
qrt - pct and western blot analysis were used to examine stemness and multi - differentiation potential of htscs.resultswe found that culturing at 5% o2 is more beneficial for the self - renewal of htscs than the other 3 culture conditions , with larger colony size and numbers .
the proliferation of htscs in 5% , 10% , and 20% o2 cultures increased after seeding .
the number of cells in the 5% o2 condition was higher than that in other culture ; however , self - renewal capacity of htscs in 0.5% o2 was inhibited .
the expression levels of stem cell markers , including ns , nanog , oct-4 , and ssea-4 , were highest in 0.5% o2 culture .
furthermore , htscs cultured in 20% o2 exhibited significantly higher expression of the 3 markers ( ppar- , sox-9 , and runx-2).conclusionshypoxic condition of culture encouraged self - renewal capacity of htscs , but inhibited their multi - differentiation potential , compared to normoxic condition of culture .
moreover , excessively low oxygen concentration impaired the capacity of htscs . |
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: understanding the difference between life expectancy and lifespan is the framework upon which any selective review of anti - aging interventions must originate from .
life expectancy is a statistical projection of the length a human being is expected to live based upon probabilities and assumptions of genetic predispositions , living conditions , medical discoveries and advances , natural disasters and other environmental factors .
morbidity statistics track presumed causes of death over time , producing trend data that can be factored into life expectancy tables ( mathers and loncar 2005 ) .
lifespan , however , is defined as the characteristic observed age of death for its very oldest individuals . throughout most of recorded human history
, it has been recognized that poor socioeconomic and nutritional status , have been strongly associated with decreased life expectancy , a trend that is also very much evident today ( us gov .
current data estimates , show that on average human life expectancy in western countries is approximately 82 years for women and 80 years for men ( us gov .
we present scientific evidence as to what anti aging practices may better serve to increase mean life expectancy and hence the human lifespan .
willet ( 2002 ) recently emphasized that genetic and environmental factors , including diet and lifestyle , both contribute to cardiovascular diseases , cancers , and other major causes of mortality and that numerous lines of evidence indicate that environmental factors are the most important in determining disease prevention .
hence , environmental factors may certainly have the strongest influence on life expectancy and hence lifespan ( figure 1 ) ( willett 2002 ; vitetta et al 2005 ) . intertwined with nutritional practices and lifestyle is life stressor modification ( vitetta et al 2005 ) .
evidence continues to accumulate that strongly suggests that the state of a human being s mind which associates psychosocial factors with emotional states such as depression and with behavioural dispositions that include hostility and psychosocial lifestyle stresses can directly and significantly influence human physiologic function and , in turn , health outcomes .
stressors and negative stress - related reactions have been documented and recognized to have multiple ill health related sequalae and exposure to chronic social stress has been associated with many systemic and mental disorders .
these have significant deleterious outcomes that significantly decrease life expectancy ( ader 2003 ; vitetta et al 2005 ) .
different research groups support the notion that health consequences are more likely to occur when unpredictable stressors of a social nature chronically induce physiological and behavioral adjustments that may create wear and tear on underlying physiological functions .
when stressors challenge an organism s integrity , a set of physiological reactions is elicited to counteract the possible threat and adjust the physiological setting of the organism to the new situation .
stresors and lifestyle choices can be a significant trigger for disease through immunomodulation of the immune system enhancing disease susceptibility , which can then affect life expectancy ( ader 2003 ) .
immune function modulation influenced and expressed by stressful life experiences has a significant correlate with willett s ( 2002 ) environmental trigger view of disease initiation .
triggers for adverse and inappropriate nutritional practices in childhood have been shown to have psychosocial correlates in adult life with an increase in risk for disease ( jackson 2005 ) .
obesity in humans , influenced by poor dietary choices and inactivity , are significantly associated with an increased risk of chronic diseases such as diabetes , high blood pressure , high cholesterol , cardiovascular diseases , asthma , arthritis , some cancers and overall poor health status , that can significantly decrease an individual s life expectancy .
cr with nutritionally poor foods ( eg , consuming half the quantity of a fast food ) is still an unbalanced nutritional choice albeit in smaller portions and still provides no health advantage .
recently it was reported and further confirmed , that a greater adherence to a traditional mediterranean diet was associated with a significant reduction in total all cause mortality ( trichopoulou et al 2003 ) .
meyer and colleagues ( 2006 ) have demonstrated that associating a cr diet with adherence to a mediterranean type diet that consisted of whole grains , beans , fish , fruit , olive oil , and many different kinds of vegetables was beneficial for heart health .
hence when optimal nutritional choices are coupled to cr , an increase in life expectancy is made possible .
that is , cr refers to a dietary regimen low in calories without under nutrition that leads to increased disease risk due to nutritional deficits .
following the pioneering work of mccay and maynard ( 1935 ) over 70 years ago , cr was then first noted to significantly extend the life span of rodents . since that time , the increase in longevity has been demonstrated to result from the limitation of total calories derived from carbohydrates , fats , or proteins to a level 25%60% below that of control animals that were fed ad libitum ( sohal and weindruch 1996 ; weindruch and sohal 1997 ; weindruch et al 2001 ) .
the extension in lifespan can approach 50% in rodents ( figure 2 ) ( mccay et al 1935 ; holloszt 1997 ) .
moreover , cr has been shown to extend the lifespan in a broad range of organisms that include , yeast , rotifers , spiders , worms , fish , mice , and rats ( weindruch et al 2001 ) .
emerging data show that its effect may also apply to non human primates ( lane et al 2001 ) .
also cr has been reported to delay a wide spectrum of diseases in different experimental animals such as kidney disease ( lane et al 2001 ) , a variety of neoplasias ( fernandes et al 1976 ; fernandes and good 1984 ; kubo et al 1984 ) , autoimmune disease ( sarkar et al 1982 ; engelman et al 1990 ) and diabetes ( shields et al 1991 ) , and it reduces age associated neuronal loss in most mouse models of neurodegenerative disorders such as parkinson s disease ( duan and mattson 1999 ) and alzheimer s disease ( zhu et al 1999 ) .
the cr regimen also prevents age - associated declines in psychomotor and spatial memory tasks ( ingram et al 1997 ) and loss of dendritic spines necessary for learning ( moroi - fetters et al 1989 ) and improves the brain s plasticity and ability for self repair ( mattson 2000 ) .
numerous biomarkers of cr have been identified in rodents , such as temperature , and dheas , insulin and glucose levels ( roth et al 2002 ) .
roth and colleagues ( 2002 ) have recently observed that body temperature and insulin and dheas levels were also altered in primates that had been subjected to cr , hence validating the usefulness of these biomarkers in longer - lived species .
more importantly , they have also shown that these parameters were altered in longer - lived men .
together these findings support the role these factors have as biomarkers of longevity in humans .
recently , a trial on the effect of a 6 month cr diet on metabolic biomarkers such as energy expenditure , and oxidative stress in humans was completed ( heilbronn et al 2006 ) .
the report showed that prolonged cr significantly reduced two biomarkers of longevity , namely , fasting insulin level and body temperature .
this is the first human study to show that cr , in addition to significant reductions in well known biomarkers of aging , also caused a metabolic adaptation in cr individuals and a reduction in dna fragmentation that reflected less dna damage ( heilbronn et al 2006 ) .
important genetic links and regulators of organism life span have been uncovered in the form of sirtuins ( sauve et al 2006 ) sirtuins are a family of nad dependent protein deacetylases widely distributed in all phyla of life . in multicellular organisms ,
sirtuins deacetylate histones and transcription factors that regulate stress , metabolism , and survival pathways .
sir2 is the founding member of a large and diverse family of these protein - modifying sirtuin enzymes , which regulate key pathways throughout biology , in eubacteria , archaea , eukaryotes , and even viruses ( sauve et al 2006 ) .
the link between cr and sir2 and aging has been reviewed elsewhere ( cf . for reviews : refer sinclair and guarente 1997 ; guarente and picard 2005 ; suave et al 2006 ) .
we further point out that there is an extensive body of evidence that suggests that sirtuins are involved in promoting longevity , particularly longevity associated with cr regimens , in several organisms .
recently suave and colleagues ( sauve et al 2006 ) hypothesized that mammalian sirt1 may mediate significant changes in tissues and endocrine systems through the sensing of low cr diets and triggering physiological changes that benefit mammals with health and hence longevity .
plant factors such as resveratrol have been shown to increase longevity in several organisms by regulating sir2/sirt1 ( cf . for review
: baur and sinclair 2006 ) . in mammals , there is growing evidence that resveratrol can prevent or delay the onset of cancer , heart disease , ischaemic and chemically induced injuries , diabetes , pathological inflammation and viral infection .
these effects are observed despite extremely low bioavailability and rapid clearance of resveratrol from the circulation ( baur and sinclair 2006 ) .
resveratrol has been suggested to be associated with the prevention of age - related diseases such as cancer because of its regulation of transcription factors that control tumuor cell survival ( guarente and kenyon 2000 ; howitz et al 2003 ; nemoto et al 2005 ; storz 2005 ) .
that mitochondria have a pivotal role in the effective provision of energy to eukaryotic cells is an undisputed scientific fact .
adenosine 5triphosphate ( atp ) is the ubiquitous energy storage molecule produced in several cellular processes .
the process is initiated by the transfer of electrons derived from food sources along a series of mitochondrial respiratory chain carriers until they are consumed with the production of water from the utilization of oxygen .
a single eukaryotic cell may contain between several hundred to thousands of these energy organelles . with increased aging
hence in aerobic animals , mitochondrial health for effective energy provision is central to life .
the free radical theory of aging , as formulated by denham harman ( 1956 ) , is supported by observations that the life span of most organisms is roughly proportional to their metabolic rate and thus due to the rate at which the organism generates mitochondria derived reactive oxygen species ( ros ) .
this view however , is over simplistic and may require modification within the confines of aging .
cellular generated ros contributing to the overall production of ros are apparently traced back to the mitochondria ( lenaz et al 2002 ) .
reports that show that in a wide spectrum of animal species , dietary antioxidants or caloric restriction , as well as chemical antioxidants or increased expression of antioxidant proteins , can lower mitochondria ros production , which translates into an extension of the life span of these species which have served to support the free radical theory of aging ( orr and sohal 1994 ; sohal and weindruck 1996 ; parkes et al 1998 ; sun and tower 1999 ; taub et al 1999 ; schon 2000 ; finkel and holbrook 2000 ; xu and finkel 2002 ) however , it is known that ros are generated in multiple cellular compartments and by multiple enzyme systems within the cell and have cellular signaling functions that are critical for the normal physiological function of the cell ( rhee et al 2003 ; linnane et al 2007a , 2007b , 2007c ) .
important contributions to the production of ros within cells , include proteins within the plasma membrane , such as the growing family of nadph oxidases ; lipid metabolism within the peroxisomes ; protein synthesis within the endoplasmic reticulum ; as well as the activity of various cytosolic enzymes such as the cyclo - oxygenases ( linnane and eastwood 2004 ; moldovan and moldovan 2004 ; balaban et al 2005 ) .
the generation of mitochondrial ros is a consequence of oxidative phosphorylation , a process that uses the controlled and regulated oxidation of nadh or fadh to generate a potential energy for protons across the mitochondrial inner membrane ( ros produced by mitochondria have been demonstrated to have important and specific roles in cellular signalling ( linnane and eastwood 2004 ) .
the notion that the mitochondria are the sole most abundant site of ros formation is currently an area of much discussion and debate ( rhee et al 2003 ; balaban et al 2005 ; linnane et al 2007b ) .
the disruption of mitochondrial functions has been implicated in more than 40 known diseases , including atherosclerosis , ischemic heart disease , cancer , diabetes , and neurodegenerative diseases such as alzheimer s disease , parkinson s disease , huntington s disease , and amyotrophic lateral sclerosis ( cf . for reviews : mckenie 2004 ; wallace 2005 ) .
together these data indicate that mitochondrial health is an important factor for health and aging .
although further research is warranted , recent reports show that supplementation with coenzyme q10 shows promise in maintaining the health of mitochondria ( kagan et al 1999 ; crestanello et al 2002 ; mckenzie et al 2004 ; somayagulu et al 2005 ; linnane et al 2007b ) .
further , mimetics of specific cellular antioxidants such as the sod / catalase mimetic euk-134 can be used to assist in reducing oxygen radicals and are already in clinical trials ( melov et al 2000 ) .
in humans there is a progressive decrease in hormone synthesis as well as a loss of hormone receptors with age .
the elderly have demonstrated significantly lower levels of production of most hormones compared to young adults ( hertogue 2005 ) . there is a voluminous body of scientific literature concerned with hormonal deficits with aging .
that is , levels of growth hormone ( gh ) and insulin like growth factor-1 ( igf-1 ) , melatonin ( nocturnal ) , tsh , thyroid hormones ( t3 ) , calcitonin , dhea ( sulphated form in and its urinary 17-keto - metabolites ) , aldosterone , estrogens , testosterone in men and women have been demonstrated to progressively decrease with age in adults ( for extensive review and individual references refer hertogue 2005 ) .
hormonal deficits are not merely limited to menopause , andropause ( male menopause ) , somatopause ( adult growth hormone deficiency ) , and other sex hormone related diseases , they are now implicated in conditions such as obesity ( cranny et al 2006 ; pasquali and gambineri 2006 ) , osteoporosis ( bennett 2005 ) , fibromyalgia ( cleare 2004 ) chronic fatigue syndrome ( cleare 2004 ) cancer ( simonenko et al 2006 ) attention deficit problems ( cheng 2005 ) and possibly others as yet that remain to be elucidated .
conventional medicine treatments have only severed to address hormone depletion , ignoring the mild and moderate deficiencies ; whereas the anti - aging medicine model focuses on mild , moderate , and severe deficiencies .
symptoms and severity of symptoms will be proportional to the level of deficiency for each hormone ( anton et al 2005 ) .
only recently has the science of endocrinology started focusing on advanced testing methods , taking into account reference ranges based on age as well as gender , free or bioavailable hormone levels versus bound hormone levels , and ratios between major antagonistic hormones to titrate patients and achieve an optimum balance .
titration and optimum balance have been used with thyroid and insulin hormones , and has not been universally applied to all other hormones , till recent times .
ongoing research in the field of longevity should include the use of nutrient and hormonal precursors to augment the body s ability to make more of its own hormonal compounds thus limiting structural and dna damage in the latter decades of life .
the purest use of the term biological aging confines it exclusively to molecular changes . hayflick ( 2003 )
defines aging in biological systems as a stochastic process that occurs systemically after reproductive maturity in animals that reach a fixed size in adulthood and that it is then caused by the escalating loss of molecular fidelity that ultimately exceeds repair capacity .
further , that there is a finitude associated with aging that eventually leads to death ( hayflick 2003 ) .
grimley evans ( 2000 ) defined senescent changes as de novo structural and functional alterations that are not part of the developmental program . in this selective and brief review
we have summarized the scientific evidence that may prevent disease and maintain the molecular integrity of the organism , thus expanding the mean life expectancy whilst operating within the framework of normal physiological function and repair .
we find that whilst aging is not irreversible and inevitable , certain key factors may add significant benefits to human mean life expectancy .
there is a vast array of scientific literature that concludes that lifestyle modification factors that optimize nutrition , physical activity and mental health have significant correlates with reducing the risks of disease in later life that is translates into an increased mean life expectancy .
further , although the correction of all hormonal deficits by an adequate multiple hormone replacement therapy , is not currently possible , hormone therapy does constitute a viable solution to prevent and treat most hormonal deficits due to pathological aging .
hertogue ( 2005 ) recently reported that even though we are not presently able to abrogate senescence by hormone treatments because of the unavailability as medications of all hormones that decline with age , the future appears promising .
as a final note ; with the onset of the 21st century , it is apparent that we stand on the horizon of a revolution in anti aging therapies and technologies . a promising therapeutic modality , the concept of stem cell treatments , will within the next decade , allow a markedly expanded quality of health and possibly also further increase the mean human life expectancy .
recent advances by major corporations , both private and public , have documented that we are already capable of taking stem cells from an individual and selectively copying these cells along with their dna components . thus making possible the restoration and rejuvenation properties that human bodies lose as they age .
the prospects for use of human embryonic stem cells derivatives in regenerative medicine hence are significant ( trouson 2006 ) .
if , the potential contributions to human regenerative medicine can be realized , significant alterations and enhancement of mean life expectancy in humans will be possible . | ### Summary:
: aging is a universal process to all life forms .
the most current and widely accepted definition for aging in humans is that there is a progressive loss of function and energy production that is accompanied by decreasing fertility and increasing mortality with advancing age .
the most obvious and commonly recognised consequence of aging and energy decline is a decrease in skeletal muscle function which affects every aspect of human life from the ability to play games , walk and run to chew , swallow and digest food .
there is hence a recognised overall decline of an individuals fitness for the environment that they occupy . in westernised countries
this decline is gradual and the signs become mostly noticeable after the 5th decade of life and henceforth , where the individual slowly progresses to death over the next three to four decades . given that the aging process is slow and gradual , it presents with opportunities and options that may ameliorate and improve the overall functional capacity of the organism .
small changes in function may be more amenable and likely to further slow down and possibly reverse some of the deleterious effects of aging , rather , than when the incremental changes are large .
this overall effect may then translate into a significant compression of the deleterious aspects of human aging with a resultant increase in human life expectancy . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: spontaneous nephrocutaneous fistula is a rare manifestation of renal disease that can occur due to various etiologies , such as renal calculus , chronic pyelonephritis , stricture of the ureteropelvic junction , and renal tuberculosis ( tb ) .
an autonephrectomy with a nephrocutaneous fistula due to renal tuberculosis can be diagnosed quite late if it is not suspected .
a 40-year - old white male with recurrent flank pain and intermittent purulent drainage from his right flank region for the previous 14 years was admitted to our outpatient clinic .
fistulography and computerized tomography demonstrated a 51 60 mm area with a soft - tissue appearance that implied autonephrectomy of the right kidney , and a fistula tract with a 9 mm diameter between the skin and the retroperitoneal space .
the patient was successfully treated with nephroureterectomy and excision of the fistulous tract , followed by antituberculous treatment .
the pathological examination of the surgical specimen revealed chronic atrophic pyelonephritis , calcifications , and necrotizing granulomatous inflammation suggestive of tb .
urogenital tb is difficult to diagnose due to the lack of specific symptoms and signs . in the case of a nonfunctioning kidney without an obvious cause and a chronic spontaneous nephrocutaneous fistula ,
the possibility of associated renal tb should be kept in mind , especially in immunocompromised patients or in places where tb is a common health problem .
spontaneous nephrocutaneous fistula is a rare manifestation of renal disease that can occur due to various etiologies .
genitourinary tuberculosis ( tb ) is seen in 15% - 20% of patients with pulmonary tb in developing countries .
spontaneous nephrocutaneous fistulas can be secondary to strictures at the ureteropelvic junction , or to necrosis and scar formation due to renal tb .
fibrosis , necrosis , and scar formation in the renal parenchyma creates a weak area , from which the leak begins ( 2 ) .
renal tb can cause various complications , including autonephrectomy in 11.5% of affected patients ( 3 ) .
in september 2014 , a 40-year - old white male who worked as a cook presented to the outpatient clinic with recurrent right flank pain and intermittent purulent drainage from his right flank region over the previous 14 years . there was no past history of any medical or surgical illness , including tb or trauma .
the physical examination revealed a fistulous orifice in the skin of the right flank region .
the patient had already used different kinds of antibiotics during this disease process , but the discharge from the fistula had never stopped .
laboratory evaluations identified a normal urine analysis , a sterile urine culture , and normal serum hemoglobin , urea , and creatine levels .
a fistulography was performed , revealing drainage of contrast agent to the kidney and the retroperitoneal space ( figure 1 ) .
computerized tomography ( ct ) demonstrated a 51 60 mm area with a soft - tissue appearance that indicated autonephrectomy of the right kidney , and a fistula tract with a 9 mm diameter between the skin and the retroperitoneal space ( figure 2 ) .
the right kidney was non - functioning on a tc99m - dimercaptosuccinic acid ( dmsa ) renal scan .
the patient was assessed by the department of chest diseases , and his tuberculin test was negative for tb .
dense adhesions of the kidney to the psoas muscle and posterior peritoneum were carefully dissected .
the pathological examination of the surgical specimen revealed chronic atrophic pyelonephritis , calcifications , and necrotizing granulomatous inflammation , suggestive of tb .
the postoperative recovery period was uneventful and the patient was discharged on the seventh day . a ziehl - neelsen stain of the nephroureterectomy specimen showed acid - fast bacilli , confirming the diagnosis of renal tb .
the patient was successfully treated for six months after the nephroureterectomy with a four - drug antituberculous therapy ( isoniazid [ 300 mg / day ] , rifampicin [ 600 mg / day ] , pyrazinamide [ 2000 mg / day , 2 months only ] , and ethambutol [ 1500 mg / day , 2 months only ] ) . at his
last follow - up visit in march 2015 , he had no complaints , and his abdominopelvic ct scan showed no pathological findings except for the solitary left kidney .
genitourinary tb is the second most common form of extrapulmonary tb , after peripheral lymphadenopathy .
tb may involve the kidney as part of a generalized disseminated infection , or as localized genitourinary disease .
however , less than 50% of patients with renal tb have radiological evidence of pulmonary tb , and active pulmonary disease is present in approximately 5% of such patients ( 4 ) .
the development of disease depends on the cellular immune response of the host , which determines the outcome of the infection .
the healing process results in fibrous tissue , and the deposition of calcium salts can result in a non - functioning kidney , known as tuberculous autonephrectomy .
renal calcifications may occur commonly in tb and require surgical intervention . in the treatment of this complication
, the aim is to ensure the protection of the renal tissue as much as possible ( 5 ) .
tuberculous bacilli reach the kidney via a hematogenous route and settle in periglomerular capillaries , leading to abscess formation .
all of these inflammatory changes result in fibrosis , calcifications , ureteral and calyceal strictures that cause loss of renal function , and autonephrectomy ( 6 ) .
in this situation , nephroureterectomy is unavoidable ; however , this is a debatable point if the kidney is non - functioning and symptomless .
some authors have proposed nephrectomy in order to prevent reactivation , while others have recommended life - long follow up . with the development of antituberculous drugs
, nephrectomy has become less important , but it can still be required in cases of uncontrolled hypertension or uncontrolled pain associated with the kidney . additionally , at the end - stage of the disease , fistulas can form to adjacent organs , requiring surgical excision of the fistulous tract and nephroureterectomy ( 7 ) . according to the european association of urology guidelines ,
the indications for nephrectomy include a non - functioning kidney with or without calcifications , extensive disease involving the whole kidney with hypertension and ureteropelvic junction obstruction , and coexisting renal carcinoma ( 5 ) .
a spontaneous renal fistula to adjacent organs is not an uncommon condition , but a spontaneous nephrocutaneous fistula is still rare .
the majority of such fistulas present as spontaneous drainage through the lumbar region , and their etiologies include chronic renal calculi , probably the most common cause .
there are some cases of spontaneous nephrocutaneous fistula due to chronic renal tb ( 8 , 9 ) .
urogenital tb is difficult to diagnose due to the lack of specific symptoms and signs .
irritative lower urinary tract symptoms , hematuria , and pyuria are the most common complaints .
abnormal radiological findings , including pyelocaliceal dilatation , ureteral stricture , hydroureter , parenchymal destruction , autonephrectomy , and calcifications , can be seen in 61.5% of patients .
a definite diagnosis can not be made with these findings , but urogenital tb should be considered in the differential diagnosis ( 3 ) .
great effort has been put into comprehensive vaccination policies throughout the world in order to eradicate tb , and although mankind has not managed eradication , the incidence has been markedly reduced . however
, much scientific evidence is currently accumulating with regard to the increased incidence of multi - drug resistant , extensively drug - resistant , and totally drug - resistant tb , and the diagnosis and treatment of tb is becoming a major issue ( 10 ) .
physicians should consider tb in the differential diagnosis for any chronic infection , and should do their best to treat accordingly . in the present case ,
although he had received various antibiotics and medical treatments over a long period , no benefit was seen .
this interesting case report of a delayed diagnosis shows us that in cases of a nonfunctioning kidney with a spontaneous nephrocutaneous fistula , we must keep in mind the possibility of associated renal tb , especially in immunocompromised patients or in geographic areas where tb is a common health problem . | ### Summary:
: introduction : spontaneous nephrocutaneous fistula is a rare manifestation of renal disease that can occur due to various etiologies , such as renal calculus , chronic pyelonephritis , stricture of the ureteropelvic junction , and renal tuberculosis ( tb ) . an autonephrectomy with a nephrocutaneous fistula due to renal tuberculosis can be diagnosed quite late if it is not suspected.case presentation : we report a case of a spontaneous nephrocutaneous fistula with tuberculous autonephrectomy .
a 40-year - old white male with recurrent flank pain and intermittent purulent drainage from his right flank region for the previous 14 years was admitted to our outpatient clinic .
fistulography and computerized tomography demonstrated a 51 60 mm area with a soft - tissue appearance that implied autonephrectomy of the right kidney , and a fistula tract with a 9 mm diameter between the skin and the retroperitoneal space .
the patient was successfully treated with nephroureterectomy and excision of the fistulous tract , followed by antituberculous treatment .
the pathological examination of the surgical specimen revealed chronic atrophic pyelonephritis , calcifications , and necrotizing granulomatous inflammation suggestive of tb.conclusions:urogenital tb is difficult to diagnose due to the lack of specific symptoms and signs . in the case of a nonfunctioning kidney without an obvious cause and a chronic spontaneous nephrocutaneous fistula ,
the possibility of associated renal tb should be kept in mind , especially in immunocompromised patients or in places where tb is a common health problem . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: we have traditionally associated the term biodefense with military applications . however , since october 2001 when anthrax spores were sent in envelopes through the us postal service , our understanding of biodefense has shifted significantly .
it has become clear that many highly pathogenic microorganisms can be considered as either agents of biological warfare or naturally occurring emerging disease threats .
in addition , we consider bioterrorism from varying points of view , including public health threats , veterinary threats , and agricultural threats . taken together , they can be considered to be
the biodefense field represents a unique challenge for vaccine development as the traditional economic models for vaccine development are based on large populations purchasing a vaccine to protect against common infectious diseases in order that a vaccine pharma can make a profit .
the situation in biodefense is very different where the goal is to stockpile vaccines with the hope that they will never be used .
relatively small markets , combined with the difficulties of working with many of these agents many of which require biosafety level 3 or 4 containment
means that there are currently no vaccines licensed for general use in the united states and most other countries for nearly all of the biothreat agents .
in addition to the traditional issues of identifying protective immunogens and platforms to deliver the vaccines , there are major difficulties in undertaking efficacy studies as most of the diseases are rare , occur sporadically , or are not found naturally .
accordingly , emphasis is being placed on appropriate animal models to demonstrate efficacy in support of licensure . however , at this time , no vaccine has been approved based on animal efficacy trials only .
nonetheless , a significant amount of data are being accumulated describing the molecular basis of disease , which provides a strong foundation for continuing product development .
the advent of the 21st century has seen our expertise in molecular biology increase exponentially . with the increasing affordability of high - throughput sequencing , concepts such as reverse vaccinology using pathogen genome sequences to produce peptides and nucleic acids for vaccine testing have become more established [ 11 , 12 ] . as our understanding of the molecular basis of pathogenesis continues to grow , coupled with large numbers of genome sequences for various pathogens becoming available and novel bioinformatics tools to facilitate their analysis , we are heading towards a position where vaccines can be rationally designed based on our molecular knowledge .
this includes selection of an optimum immunogen and delivery system to maximize the host protective immune response rather than empirical approaches that were used for much of the 20th century .
the continuing generation of high - throughput datasets characterizing high - priority biodefense and public health pathogens , and their host responses in the post - genomic era , will require novel bioinformatic techniques .
these computational approaches will allow a more complete and thorough understanding of infection and pathogenesis , and greatly facilitate rational vaccine design .
this review describes some of these methods and how they can be used in the development of novel vaccines against biothreat viruses .
techniques such as microarray expression profiling , 2d gels , automated spot picking and peptide sequencing , and other high - throughput methods have revolutionized the study of virus interactions with the host cell . in particular , microarray analysis has proven a very useful tool in the emerging virus and biodefense field as the rna extraction process facilitates removal of samples from the biosafety level 3 ( bsl-3 ) or bsl-4 laboratory where only inactivated samples are allowed to leave biocontainment .
many pathogenic viruses interfere with the development of a protective immune response by preventing the activation of key aspects of the immune response , from inhibition of irf-3 phosphorylation to block type - i interferon synthesis to sequestering mhc - i in the cell to prevent display of virus - derived peptides .
a central feature of many biothreat pathogens is the infection of macrophages and dendritic cells as the primary target for replication .
infection of these cell types enables viruses to prevent immune response development at an early , central stage .
for example , dendritic cells infected with lymphocytic choriomeningitis virus ( lcmv ) , an old world arenavirus used to infect macaques as a model for lassa fever , lead to downregulation of mhc - ii on the dendritic cell surface , inhibiting the ability of these cells to present antigen and develop the adaptive immune response while marburg virus infection of macaques leads to downregulation of mhc - ii on dendritic cells in the spleen .
effects such as these are common following infection with these viruses resulting in significantly impairment of the host to develop a protective immune response at an early stage of infection .
the downregulation of mhc - ii has also been observed in a microarray study of pbmcs from lcmv - infected macaques with pathogenic virus inducing a greater downregulation than infection with attenuated virus .
interestingly , mhc - ii was upregulated in liver tissues , highlighting the importance of animal models and role of the host as having different functional systems , which may respond differently to a similar challenge at the molecular level .
the contributions that host - pathogen interaction profiling can make to vaccine development are exemplified by a study which determined that substitution of a single amino acid in the vp35 protein of ebola virus is sufficient to disrupt the viral inhibition of innate immune signaling , while maintaining the ability to replicate to wild - type levels in cell culture .
similarly , deletion of an entire multigene family , with a hypothesized role in modulation of the interferon system , still results in viral replication . if the viral proteins responsible for mediating inhibition of the host immune response can be determined , then targeted mutations can be made to disrupt these effects , counteracting the inhibition of the host immune response and allowing the host to induce either an innate and/or a protective immune response . in this way
, live - attenuated viruses may be developed for further characterization as novel vaccine candidates .
large dna viruses , such as variola virus , the causative agent of smallpox , contain large genomes of almost 200 kb encoding several genes that modulate the host immune response . in these situations
, individual proteins may have a single function only , allowing entire genes to be knocked out to attenuate the virus , as is seen with vaccinia virus . in some cases
, sufficient redundancy may exist requiring the deletion of multiple genes or whole genome sections to sufficiently attenuate the virus .
for example , african swine fever virus , from another family of large dna viruses , causes a hemorrhagic disease in domestic pigs and encodes a number of genes that modulate the host immune response .
one such gene , a238l , encodes a protein which inhibits the transcription factor nf-b , a central regulator of inflammation and the innate immune response .
however , deleting this gene does not cause any difference in porcine disease . similarly ,
deletion of an entire multigene family with a hypothesized role in modulation of the interferon system still results in viral replication [ 21 , 22 ] .
however , all of the current biothreat viruses , with the exception of variola virus , are rna viruses , with limited coding capacity and proteins that have multiple functions . in these cases ,
this illustrates the importance of identifying the individual residues / regions responsible for specific virus - host interactions . if specific residues are identified that are important in determining virulence or in modulating the host immune response , but do not interfere in the critical functions of viral replication , mutation of these sites may lead to novel vaccine candidates .
for example , recent mapping of the nipah virus p gene has identified a region that is required for inhibition of stat-1 signaling , but without disrupting its function as a cofactor for the viral polymerase .
the use of global approaches , particularly microarray gene expression technology , has provided a wealth of information detailing the host responses to infection .
while these data are often limited to transcription rather than expression at the protein level , they have provided significant insight into which classes of host genes are up- and downregulated in response to virus infections .
a novel application of this technology is to use the differentially expressed genes as a marker of upstream transcription factor activation using bioinformatics tools such as carrie [ 24 , 25 ] . in this way ,
host signaling pathways activated or repressed by virus infection can be inferred and studied further , in particular those inhibited by virus - induced proteins that are critical in the pathogenesis of the virus ( see below ) .
the study of virus - host interactions has helped to identify host proteins required for particular stages in the virus life cycle .
identifying such cellular proteins may allow the development of novel therapeutics , for example , by inhibiting a cellular kinase required for viral entry or replication [ 2628 ] .
however , it is likely that these studies may not provide the key information required to aid the development of novel vaccines as elucidating correlates of protection is not possible if the study compares candidate vaccine - infected versus mock - infected groups without including wild - type virulent virus - infected groups or vice versa . currently , there are few high - throughput systems - level studies employing these types of comparisons in vivo
. analyses of human transcriptional responses to the yellow fever 17d vaccine have provided significant insights into the host response to this attenuated virus , but such studies , not surprisingly , lack inclusion of the human response to asibi virus ( the wild - type parent to vaccine strain 17d ) and limit our knowledge of the molecular basis of attenuation of 17d virus .
however , studies using virulent / attenuated pairs , such as lcmv we / armstrong infection in macaques [ 15 , 16 ] , allow one set of responses to be subtracted from the other , filtering the dataset down to a more manageable size for further analysis and potential correlation of transcriptional profiles with pathogenesis or protection .
as higher - throughput sequencing becomes ever more affordable , whole genome sequencing of many virus strains and species is becoming more commonplace .
many of these types of study have been undertaken from an epidemiological perspective in order to trace the natural history of virus strains and determine and predict their spread .
genomic sequence analysis of large numbers of naturally occurring field strains of viruses will be important in the process to identify specific mutations that correlate with differences in pathogenicity of these viruses , and subsequently the process of attenuation .
comparing the cellular responses to infection by virulent and attenuated viruses has provided a large amount of information on the molecular basis of pathogenesis that may have application to developing correlates of protection . a significant trend that seems to be emerging
is that infection with attenuated viruses promotes a strong immune response , while these events are suppressed in virulent infection .
a number of virus pairs have been used for these types of analyses . a microarray study of mouse brain tissue following infection with wild - type or a laboratory - adapted strain of rabies virus revealed extensive activation of the inflammatory response and the type - i interferon system in mice infected with the attenuated virus . studies using pichind virus , a guinea pig model for lassa fever , have taken advantage of two passage variants of the virus which cause either a severe hemorrhagic fever or a mild , self - limiting infection from which animals recover [ 31 , 32 ] . proteomic and kinomic level studies using this system
have been analyzed using pathway analysis and have shown that infection with the attenuated virus induced significantly more cellular signaling events and immune response activation than infection with the virulent virus , which more closely resembles patterns of protein expression and kinase activity seen following mock infection [ 3335 ] .
these systems - level analyses can be used to generate hypotheses and tested using pathway - focused assays .
analysis of nf-b family activity showed increased expression and dna binding of a transcriptionally repressive nf-b protein following virulent infection consistent with observations that pathogenic arenavirus infection fails to activate cells .
the genomes of the virulent and attenuated pichind viruses have been sequenced and the amino acid differences between them identified .
the striking differences in phenotype are caused by a small number of mutations , with three amino acid differences in the envelope glycoprotein precursor , one in the nucleoprotein , and five in the polymerase .
interestingly , while the nucleoprotein has been shown to play an important role in the inhibition of interferon induction [ 38 , 39 ] , the mutation observed in the pichind virus nucleoprotein does not inhibit this function .
taken together with the observation described above that a single amino acid in the vp35 protein of ebola virus is sufficient to disrupt the viral inhibition of innate immune signaling , it suggests that modulation of immune function is not the sole determinant of pathogenicity for this virus .
the recent development of an infectious clone system will allow further characterization of the roles of these mutations and shed light on the relation of individual amino acid changes to arenavirus pathogenesis .
a number of studies have compared lassa virus with the related naturally nonvirulent arenavirus mopeia virus .
infection of monocytes , targets of arenavirus infection in vivo and central mediators of the development of a protective immune response , with lassa virus does not result in cell activation or production of tnf- or il-8 , and consequently the host immune response to virus infection is inhibited .
in contrast , il-8 production is not suppressed and interferon signaling is activated in mopeia virus - infected cells , allowing the host immune response to be induced [ 41 , 42 ] .
dendritic cells , which are professional antigen - presenting cells , are also targets of hemorrhagic fever virus infection .
lassa virus infection of dendritic cells inhibits upregulation of the correct cell - surface expression of proteins involved in antigen presentation , adhesion , or activation , again inhibiting the development of the adaptive immune response .
observations of lassa fever patients demonstrated higher il-8 and interferon - inducible protein 10 levels in patients who recovered from infection compared to those with fatal outcome , which corroborates in vitro studies suggesting that functional impairment of immune responses contributes to pathogenesis .
however , given the ability of runaway immune responses to cause an immunopathology or a
cytokine storm-like disease following infection by some viruses , immune mechanisms need to be appropriate and controlled to allow the development of the correct responses and lead to clearance of the virus . in the case of sars coronavirus
, a microarray study demonstrated that early induction of host responses and proinflammatory signaling was correlated with a fatal outcome of infection in aged mice .
two attenuated variants of rift valley fever virus ( rvfv ) , a bunyavirus and category a priority pathogen , have also provided insights into how differences in viral genome , host interactions , and pathogenesis can identify important viral virulence determinants .
the nss protein mediates the inhibition of the type - i interferon response , a critical mediator of the innate response to viral infection important in establishing appropriate secondary immune developments .
the clone 13 strain of rvfv has a large deletion in the nss coding region , removing its ability to inhibit the type - i interferon response , which leads to a highly attenuated phenotype in mice , but retains immunogenicity , and is a potential candidate vaccine [ 4649 ] .
integrating the virus infection data using pathway analysis and functional systems biology tools can provide an overview of the similarities and differences between infections by either a virulent or an attenuated variant of a virus .
for example , inferring the upstream transcription factors that are differentially activated between attenuated and virulent infections from microarray data may allow the responsible signaling pathways to be identified .
if activation of a specific signaling pathway is associated with the expression of a subset of genes associated with the development of a protective immune response , this pathway could be targeted for stimulation as a novel adjuvant strategy , or its activity assayed as a proxy for potential efficacy if screening several vaccine candidates .
while the continued discovery of the types of virulence determinants discussed above by the study of virus strains that differ in pathogenesis illustrates the power and simplicity of this approach , the above examples demonstrate the important point that characterization of the appropriate immunological events associated with protection differs from pathogen to pathogen and from model to model . as datasets from global host - pathogen interaction studies continue to become available , novel meta - analyses at the systems level may allow particular patterns associated with pathogen , host , and disease pathology to be observed , which can feed back into models for vaccine development . at present
, most studies are concentrating on the innate immune response , in particular the interferon signaling pathway , rather than the adaptive immune response .
the major difficulty of all these studies is undertaking studies on wild - type virulent virus in human cells due to biocontainment requirements for studies in cell culture and animal models , while studies in humans are very hard to undertake as patient samples do not usually become available until late in the disease course or from deceased individuals .
high - throughput omics experiments provide an almost overwhelming amount of data for validation and further studies , which makes interpretation difficult . as such , analysis
is often limited to a heatmap following hierarchical clustering analysis to obtain a broad overview of the dataset and the relationships between the treatment groups , with the transcripts showing the highest fold - changes selected for confirmation by rt - pcr and further experiments . with the majority of recent work focusing on either the underlying molecular biology of virus infection and cellular responses or disease pathology at the histological level ,
emerging bioinformatics tools , and the continued use of experimental methods that characterize cellular regulation at a number of levels , from mrna expression to metabolomics , will allow these two extremes to be linked , providing a holistic systems - level view of pathogenesis .
importantly , these levels of increased understanding will be beneficial to many areas of research , including vaccinology , as we will ultimately be able to screen vaccine candidates based on the effects on particular host genes and/or proteins following infection ( e.g. , lack of inhibition of interferon signaling pathway ) of a particular cell type , and later in appropriate animal models , with the vaccine candidates .
an iterative algorithm then refines the clustering until each transcript is in the cluster with the closest mean average . in this way
if gene expression analysis is used to compare the cellular responses following infection with mock , wild - type and attenuated or candidate vaccine strain viruses , groups of genes that may be specifically up or downregulated by a particular virus variant , will become apparent .
figure 1 shows a generic example of the type of output produced following k - means clustering .
as can be seen , the three clusters show groups of genes that are upregulated following wild - type but not attenuated virus infection , genes upregulated as a consequence of both infections , and a cluster of genes which are upregulated by attenuated but not wild - type infection .
this latter group of genes may represent those that are required to initiate a protective immune response and indicate potential biomarkers of protection .
an approach that is becoming more widely used in this field is that of pathway analysis . using knowledgebases of known interactions between proteins , dna , rna , and small molecules ,
large datasets can be placed into a more functional context on the basis of their known interactions .
pathway analysis tools such as cytoscape [ 51 , 52 ] and the ingenuity pathway analysis software are increasingly used to understand protein and gene interactions and construct so - called signaling networks
these types of approaches have also been used to analyze interactions and network relationships between viral proteins as well as to characterize the interaction of viral proteins with cellular proteins [ 5456 ] . however , to date , these types of mapping analyses have required high - throughput yeast two - hybrid type assays to generate the input data .
consequently , this type of approach may not yet be suited to the high - throughput identification of protein interaction networks for large numbers of virus strains , including potentially attenuating mutations .
furthermore , the yeast 2-hybrid system does not always generate practical meaningful interactions and a significant number of experiments are required to substantiate protein interactions .
however , machine learning approaches have been applied to the determination of protein - protein interactions . in particular ,
support vector machines have been used to predict protein - protein interactions on the basis of sequence information alone .
support vector machines ( svms ) are a machine learning approach which allows binary classification following training of an algorithm on a test - set of data .
the svm is trained on a dataset which includes a number of parameters where the classification is known .
the svm develops an algorithm that , when given a set of parameters ( n ) of unknown classification , can be used to predict the class on the basis of the training set .
the svm transforms the data , places it into n - dimensional space , and attempts to separate the data by class by defining a hyperplane through this feature space ( figure 3 ) .
the advantage of these types of methods is that the number of parameters can be tailored to strike a balance between what is experimentally feasible and predictive accuracy .
as the number of parameters increases , classification accuracy may improve , but collecting the data may become less feasible experimentally . with training sets constructed from known protein - protein interactions defined experimentally ,
svm - based approaches have shown increasing accuracy for predicting these interactions [ 5759 ] . using these approaches , it may be possible to screen large numbers of protein sequences in silico to elucidate amino acid mutations to disrupt protein - protein interactions that may attenuate a virus , such as the single amino acid substitution that significantly attenuated ebola virus .
their approach takes advantage of the redundancy of the triplet genetic code and the fact that there is often a codon usage bias , where particular codons are used more or less often to code for a particular amino acid than would be predicted by chance .
they developed a computer algorithm that recoded a given amino acid sequence at the genetic level , changing the codon pairs to those which were under - or overrepresented in the wild - type sequence .
their algorithm also included other features such as rna folding - free energy , a factor shown to be implicated in hostadaptation of influenza virus . by altering codon pair usage
, they were able to construct a poliovirus that was attenuated in mice and provided protective immunity .
of particular interest with this type of strategy is that the protein sequence remains unchanged from the wild - type virus .
as discussed above , the majority of high - throughput data to emerge from the biodefense field has been microarray mrna expression data , rather than from high - throughput protein interaction data that directly lend itself to network analysis .
however , genomics- and proteomics - level analyses have produced interaction networks that are beginning to yield some consistent and overlapping signaling pathways across different model systems , and novel computational approaches are providing alternative strategies for virus comparison and attenuation .
traditionally , live - attenuated viruses have been developed by serial passage of wild - type viruses in culture .
the live - attenuated yellow fever 17d and the polio sabin vaccines were developed in this way .
however , the attenuated poliovirus vaccine can revert to virulence and has been associated with vaccine - associated poliomyelitis . in recent years
, the yellow fever 17d vaccine has caused a number of serious adverse effects with a significant case fatality rate [ 6365 ] . some of these outcomes may be associated with polymorphisms in the ccr5 chemokine receptor and rantes chemokine genes in some vaccinees .
if the vaccine - associated disease is associated with hostpolymorphisms rather than with virus reversion , then determining vaccine safety becomes increasingly complicated and suggests that in the 21st century each vaccine may become restricted to individuals with a particular host genetic background . as high - throughput methods become more affordable , personalized vaccinology may be a strategy that becomes more feasible .
personalized vaccinology refers to the ability to tailor particular vaccines to specific individuals [ 67 , 68 ] .
if , for example , adverse responses to the yellow fever vaccine can be attributed to a specific genetic polymorphism , then the vaccinee can be screened for this polymorphism , and decisions whether or not to vaccinate can be made on that basis .
if alternate vaccines are available , which perhaps offer a shorter - lived immunity but without reported adverse effects , appropriate risk assessments can be made and a course of action determined , in the best interests of the individual vaccinee .
the two basic requirements for vaccine design are the induction of a protective immune response and safety .
studies of human responses to the yellow fever vaccine using mrna microarrays have revealed the immune pathways responsible for protection [ 29 , 69 , 70 ] .
unfortunately , as these studies were performed in human volunteers , there is no directly comparable dataset following exposure to wild - type yellow fever virus infection .
as discussed above , this raises one of the problems of utilizing system biology in vaccine development ; namely , studies with candidate and licensed vaccines in humans are comparatively easy while obtaining samples from wild - type infections and serious adverse events are very difficult for a variety of reasons .
however , these studies do reveal significant insights at the molecular level into how a historically very successful vaccine induces protection .
these studies showed activation of several arms of the immune response but identified key transcription factors which acted as master switches in immune response development .
pathway analysis revealed these to be central hubs : highly connected nodes in a signaling network .
there are a number of biodefense vaccines in investigation new drug ( ind ) status , due to limited studies on safety and efficacy , which are administered to individuals who are at risk from the disease .
bioinformatic studies on vaccinees who receive these ind vaccines may help generate important data that have application to safety and efficacy .
microarray studies characterizing the global host responses to the adjuvants alum , cpg , mf59 , and ltk63 have identified transcript signatures common between and specific to these adjuvants [ 71 , 72 ] . by understanding how these transcriptional responses correlate with the development of specific immune mechanisms ,
appropriate pathways could be stimulated with specific vaccines to induce the appropriate immune effector functions for that pathogen : as efforts to design vaccines to be as safe as possible continue , a potential side effect could be over - attenuation leading to increased safety at the expense of immunogenicity and lasting protection .
a possible solution could be the use of novel adjuvants to stimulate the signaling pathways associated with a strong immunogenic response .
as an example , inflammasome activation was found to be a central regulator of the immune response to yellow fever vaccine .
interestingly , a novel nanoparticle - based vaccine delivery method has recently been reported which includes lipopolysaccharide to activate the inflammasome alongside delivery of a protein subunit vaccine .
as our understanding of the correlates of protection for currently licensed vaccines increases , we may be able to target specific cellular pathways to tailor immune responses to a new generation of highly attenuated , safe vaccines .
recently , a machine learning algorithm , based on a support vector machine , was used to identify potential correlates of immune protection , with potential transcript - based indicators of cell - mediated and antibody responses identified . while these findings require further validation and comparison with potential indicators for responses to other vaccines , they suggest that bioinformatics could provide tools to predict immunization outcome soon after vaccination .
additionally , pathway analysis can be used to screen for transcriptional responses which are associated with other diseases or adverse effects , potentially providing a means to assay vaccine safety in vivo early in the development process .
currently , a limiting factor in the rational attenuation of biodefense viruses for vaccine design is in obtaining datasets from equivalent platforms and model systems , facilitating meta - analyses to determine potential correlates of attenuation .
however , while the virus - host interaction field may not yet be addressable in this way , efforts are being made to compile easily accessible databases of viral sequences for query .
one such database has collected over 300 protein sequences from pathogenic arenaviruses to aid in epitope discovery studies .
combining these types of databases with patient data such as antibody titer or disease severity may allow consistent peptide sequences which correlate with immune protection to be determined .
this type of approach , combined with computational mhc epitope prediction , will significantly further our ability to rationally develop immunogenic vaccine candidates .
the increased availability and affordability of high - throughput technologies , such as whole genome sequencing and omics analyses , will allow the continuing development of large , multilevel datasets to characterize host responses to pathogens of differing virulence , and the changes in viral sequences responsible .
as bioinformatics continues to evolve , and as microbiologists , immunologists , and vaccinologists become more familiar with the potential of these technologies , the stage will be set for novel approaches to vaccine design for biodefense , combining rational attenuation with immunogenicity and safety testing . by integrating these approaches early in the process , and using a combination of in vitro and in silico techniques , vaccine candidates with the most promise can be selected for further testing with a greater confidence , and funding can be better appropriated .
the use of comparative studies between virulent and attenuated strains could provide a wealth of data to assist in vaccine development .
while many datasets have been published , comparison across different experimental systems remains an issue .
ideally , cell lines , timepoints , and other experimental criteria need to be standardized to allow informed comparison of the results .
the ability to perform meta - analyses across different studies could allow a better understanding of what host responses are required to lead to a long - lasting protective immune response .
if a dataset which characterized the host responses to yellow fever vaccine could be compared with similar datasets showing responses to other live vaccines , for example , smallpox vaccine and junin vaccine , along with response to the appropriate wild - type agents , we will undoubtedly find several groups of similarities and differences which associate with protection , virulence , or type of virus or disease pathology .
these approaches to vaccine design illustrate how vaccinology can use the data from basic science , and particularly studies of molecular pathogenesis , to develop novel vaccine candidates . by identifying common cellular responses to attenuated virus vaccines , across different viral families and different wild - type disease pathologies
, we may characterize a central core of responses which are always activated by a historically successful vaccine , regardless of virus type .
these responses can guide us in the development of novel vaccine candidates or adjuvants . as new viruses continue to emerge and
the risks from emerging and remerging pathogens remain , the need for vaccines against these pathogens remains significant .
the introduction and spread of west nile virus to north america illustrates how quickly viruses can become established in a new area and present novel threats to public health .
the continuing investment in biodefense and emerging pathogens will result in even greater amounts of basic data to input into novel bioinformatics tools .
as our understanding of the molecular determinants of protection and pathogenesis continues to grow , the development of safe , effective vaccines to these important pathogens will continue to accelerate . | ### Summary:
: developing vaccines to biothreat agents presents a number of challenges for discovery , preclinical development , and licensure .
the need for high containment to work with live agents limits the
amount and types of research that can be done using complete pathogens , and small markets reduce potential returns for industry .
however , a number of tools , from comparative pathogenesis of viral strains at the molecular level to novel computational approaches , are being used to understand the basis of viral attenuation and characterize protective immune responses . as the amount of basic molecular knowledge grows
, we will be able to take advantage of these tools not only to rationally attenuate virus strains for candidate vaccines , but also to assess immunogenicity and safety in silico .
this review discusses how a basic understanding of pathogenesis , allied with systems biology and machine learning methods , can impact biodefense vaccinology . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: leiomyosarcoma is a malignancy of the soft tissue and accounts for 510% of soft tissue sarcomas .
leiomyosarcomas are histologically similar , occur in varied locations , with the retroperitoneum being the most common site , and are spread by hematogenous route .
uterine leiomyosarcomas are more aggressive and carry a poor prognosis irrespective of the stage of presentation
. they may be present in the uterus with leiomyomas , and both tumors may express the estrogen receptor ( er ) and the progesterone receptor ( pr ) .
the presence of 2 out of the 3 stanford criteria , namely : prominent cellular atypia , areas of tumor necrosis and abundant mitoses has been correlated with a > 10% risk of metastasis .
they often present as vaginal bleeding and may be detected by ultrasound imaging during initial workup .
the incidence of leiomyosarcoma in african - american woman is approximately 2-fold higher than in caucasian women .
tamoxifen usage and pelvic radiation may increase the risk of development of uterine sarcoma [ 7 , 8 , 9 ] .
the presence of symptoms such as an enlarged uterus , vaginal bleeding , abdominal distension , urinary frequency , etc .
, in a postmenopausal woman with a prior history of leiomyomas should raise the suspicion of leiomyosarcoma .
uterine leiomyosarcomas have been known to spread to distant sites including the lung , abdomen , brain , breast , bone , skin , pancreas and kidney [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ] .
brain metastasis has been rarely observed and peritoneal sarcomatosis has been occasionally documented [ 16 , 18 ] .
it is rare to detect an er- and pr - positive mass actively growing on a heart valve .
this case highlights the unusual presentation of uterine leiomyosarcoma as a mass attached to the tricuspid valve ( tv ) .
the location of the mass may contribute to hemodynamic instability and surgical intervention may be required immediately after presentation .
the patient is a 49-year - old woman with a past medical history significant for uterine fibroids and menorrhagia who presented with a complaint of heavy vaginal bleeding over the previous 8 days , progressive weakness , lightheadedness , palpitations , dyspnea on exertion and lower abdominal pain .
her uterine fibroids were treated in the past by blood transfusion and bilateral uterine artery and left ovarian artery embolization .
she was not allergic to any medications and denied smoking tobacco , consuming alcohol or using intravenous drugs .
she was noted to have a hemoglobin level of 5.1 g / dl and received 5 units of packed red blood cells and levonorgestrel .
her shortness of breath improved marginally but she continued to have tachycardia . she was noted to have left lower extremity swelling which the patient admitted had started 45 days prior to admission . a lower extremity doppler ultrasound revealed extensive deep venous thrombosis and she was started on systemic anticoagulation with dalteparin .
a chest ct showed saddle embolus and multiple bilateral pulmonary emboli with evidence of right heart strain .
multiple bilateral pulmonary nodules suspicious for metastatic disease and a moderate right - sided pleural effusion and a trace left - sided pleural effusion were also noted ( fig .
her physical examination was pertinent for tachycardia , normal breath sounds , distended abdomen with tenderness to palpation in the lower quadrants ( uterus was palpable ) and bilateral calf muscle swelling with tenderness .
however , the next day morning the patient was noted to become severely hypoxemic with an altered mental state .
she was intubated and started on vasopressors for shock . due to persistent hypoxemia and hypotension
intraoperative transesophageal echocardiography revealed an underfilled left ventricle with interventricular septum flattening , massively dilated right atrium and an extremely dilated right ventricle with reduced function .
it also showed a mild - to - moderate pulmonary artery ( pa ) dilatation with a large mass in the right pa ( possibly thrombus ) and a severe tricuspid regurgitation with a large pedunculated , very mobile mass attached to the tv leaflets that moved from the right atrium to the right ventricle during the cardiac cycle ( fig .
intraoperatively , a large thrombus at the bifurcation of the pa which was extending into the pa branches was removed .
the right atrium and the right ventricle were found to be devoid of any clots , but a worm - like mass attached to the anterior tv leaflet was identified and removed .
also a left lower lobe wedge resection was performed on a peripheral nodule and the right pleural effusion was drained .
the patient continued to require a maximal dose of vasopressors and had to be maintained on extracorporal membrane oxygenation and renal replacement therapy .
she was successfully extubated on postoperative day 6 and was transferred to the medical floor .
histology of the mass attached to the tv and the pulmonary nodule revealed spindle cells with marked nuclear atypia , frequent mitoses , extensive necrosis and vascular invasion consistent with leiomyosarcoma ( fig .
immunohistochemistry was positive for smooth muscle actin ( sma ) , desmin , er , pr and cyclin - dependent kinase inhibitor 2a ( p16 ) ( fig .
f ) . it was negative for myogenin , myogenic differentiation 1 ( myod1 ) and cytokeratins ( ae1/3 ) .
the pleural fluid showed rare , isolated highly atypical cells of uncertain origin and scattered mesothelial cells .
it is likely that this patient suffered from a massive pulmonary embolism due to a combination of a predisposed state of hypercoagulation due to malignancy and due to the possible obstructive nature of the mass on the tv .
these findings suggest that uterine leiomyosarcoma may manifest itself as a mass on the heart valves , and early identification may help prevent life - threatening complications .
uterine leiomyosarcoma is a rare malignancy and comprises about 1% of uterine malignancies , with an annual incidence of 0.64/100,000 women .
the histopathological diagnosis is often made after hysterectomy as endometrial biopsies or dilatation and curettage may not yield adequate tissue .
these tumors are thought to arise independently and less than 5% of them arise from transformation of preexisting leiomyoma .
they differ from leiomyomas and smooth muscle tumors of uncertain malignant potential ( stump ) by the presence of atypia , mitoses and tumor necrosis .
these tumors often present in the fifth decade of life , usually as a pelvic mass with vaginal bleeding . on ct and
mri imaging they may present as submucosal , intramural or subserosal masses which are heterogeneously enhancing with hemorrhage or calcifications [ 24 , 25 ] .
definitively differentiating the radiological appearance of leiomyosarcomas from leiomyomas has not been successful and histopathological diagnosis continues to be the standard . the size and rapidity of growth
there is a low propensity for pelvic node involvement , but ct has been the most common imaging modality for investigating the presence and extent of extra - uterine disease and distant metastasis .
further investigation is required for fdg - pet to be established as an imaging modality for leiomyosarcomas .
the stage of the disease , mitotic count and tumor grade have been shown to be significant factors to help determine the prognosis .
hysterectomy has been the main stay of treatment with preservation of the ovaries , but pelvic lymphadenectomy has not been advocated due to the low involvement of pelvic lymph nodes [ 23 , 30 ] .
doxorubicin had been the agent of choice until a combination of gemcitabine and docetaxel was found to have an overall response rate of 53% in patients with advanced unresectable uterine leiomyosarcoma .
trabectedin has been approved for use in europe and is being currently investigated in combination with doxorubicin [ 33 , 34 ] .
hormonal agents such as megestrol , medroxyprogesterone and aromatase inhibitors are being investigated , but the increased risk of side effects like venous thromboembolism and osteoporosis are being recognized as impediments to their use [ 35 , 36 ] .
radiotherapy has been shown to help improve pelvic control , but there is no evidence for similar benefit for distant metastasis .
| ### Summary:
: uterine leiomyosarcoma is a rare malignancy and carries a poorer prognosis when compared to endometrial carcinoma .
it has been observed to metastasize to all the major organs .
it presents with symptoms of abdominal distension , vaginal bleeding and may pass unnoticed until an advanced stage in patients with leiomyomas .
surgery is a viable option in patients with disease limited to the uterus , but metastasis to the heart may require surgery to prevent acute and catastrophic complications .
the case described here involves metastasis to the tricuspid valve , which caused severe tricuspid regurgitation in the setting of acute pulmonary embolism .
surgical resection restored cardiac function and stabilized the patient .
this case illustrates a rare site of metastasis of leiomyosarcoma which required immediate intervention and resulted in a favorable outcome . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: chemicals and solutions - triton x-100 , schneider 's insect medium , poly - l - lysine , dimethylsulfoxide ( dmso ) , fitc - conjugated anti - alpha tubulin antibody ( clone dm1a ) , taxol , chlorpromazine , ansamitocin p3 ( ap3 ) , tfp and rhizoxin were obtained from sigma ( st louis , mo ) .
stock solutions of each drug were prepared in dmso and stored at 4c or -20c following the manufacturer 's instructions .
osmium tetroxide , lx resin , glutaraldehyde and formaldehyde were obtained from electron microscopy sciences .
isotonic chloride buffer ( 137 mm nacl , 4 mm kcl , 1.5 mm kh2po4 , 8.5 mm na2po4 , 20 mm hepes , 11 mm glucose , 1 mm cacl2 , 0.8 mm mg so4 ) was adjusted to ph 7.4 .
the osmolarity of the buffer was 300 5 mosm ( isosmotic ) and 150 mosm 7 mosm as measured in an advanced digimatic osmometer .
parasite culture - l. mexicana promastigotes of strain nr ( ramirez & guevara 1987 ) were isolated from infected mice and cultured at 26c by serial passage every five days in schneider 's insect medium supplemented with 10% inactivated fbs ( ph 7.4 ) .
axenic l. mexicana amastigote - like forms were obtained following incubation of promastigotes in schneider 's insect medium supplemented with 20% fbs ( ph 5.5 ) at 35c in the presence of 5% co2 for 24 h.
fluorescence microscopy - l. mexicana promastigotes were grown in the presence or absence of 100 nm ap3 . following three washes in phosphate - buffered saline ( pbs ) ( 150 mm nacl , 20 mm phosphate buffer , ph 7.4 ) , they were placed on glass cover slips coated with poly - l - lysine , fixed with 3% ( v / v ) freshly prepared formaldehyde solution in pbs at 26c for 10 min , washed in pbs and permeabilised with 0.1% ( v / v )
after 5 min of treatment with ammonium chloride followed by three washes in 0.2% gelatin in pbs , the cells were incubated with a 1:100 dilution of fitc - conjugated anti - tubulin antibody ( clone dm1a , sigma ) for 40 min in a humidified chamber in the dark .
the cover slips were washed with pbs , rinsed with water and finally mounted on glass slides with a drop of mounting medium ( moviol hoechst ) .
transmission electron microscopy ( tem ) - parasite cells ( 1 x 10 grown in the presence or absence of 100 nm ap3 for 48 h were washed in pbs and the pellets were fixed for 1 h with 2.5% glutaraldehyde in pbs at 4c .
the cells were washed again in pbs and post - fixed for 1 h in pbs containing 1% osmium tetroxide .
the cells were then washed in the same buffer , dehydrated in a graded ethanol series followed by propylene oxide and finally embedded in epon .
ultrathin sections were stained with uranyl acetate and lead citrate and observed with a jeol transmission electron microscope .
light scattering - rvd of control cells and 50% of inhibitory concentration ( ic50 ) drug - treated cells was monitored over 48 h by measuring light scattering of the cellular suspensions at 550 nm ( a550 ) in 1 ml glass cuvettes at 26c using a beckman du-7500 spectrophotometer ( park et al .
the cells were washed once and resuspended in 300 mosm chloride buffer to a final concentration of 1 - 2 x 10 cells / ml . a550 readings were registered every 20 sec for 10 min .
hypoosmotic conditions were induced by diluting the isotonic cell suspension with an appropriate volume of deionised water to a final osmolarity of 150 mosm .
a decrease in the a550 reading indicated cell swelling ( an increase in the cell volume ) .
plasma membrane - cytoskeleton complex preparation - leishmania promastigotes grown in the absence of drugs were separated into two batches .
one batch was subjected to the procedure described in this section for immunofluorescence visualisation of mts ( control cells ) .
the other batch , together with leishmania promastigotes , grown in the presence of 100 nm ap3 over 48 h , was washed three times in pbs and resuspended in buffer a ( 20 mm hepes - 20 mm nacl ph 7.4 ) for 5 min .
the cells were centrifuged at 1500 g for 10 min and the pellets were resuspended in buffer b [ 20 mm hepes - 100 mm nacl - 0.5% ( v / v ) triton x-100 , ph 7.4 ] .
the cells were sedimented again under the same conditions and were washed and resuspended in buffer c ( 100 mm hepes - 100 mm nacl , ph 7.4 ) following a modification of the procedure previously reported for preparing the leishmania plasma membrane cytoskeleton complex ( " ghost " ) ( bordier et al .
control cells and triton x-100 " ghosts " of control and drug - treated cells were used for immunofluorescence .
antiproliferative activity of drugs on leishmania promastigotes - the effects of the five distinct anti - mt drugs on promastigote proliferation were assessed by measuring the optical density of the cell cultures at 560 nm every 24 h for five days .
the drugs were added to the log - phase promastigote cultures when they reached a final density of 2 x 10 parasites /ml .
each drug was added to the cultures in a range of concentrations determined previously by measuring the antiproliferative activities of the drugs .
the drug stocks were dissolved in dmso and the final concentration of dmso in the assays was always less than 1% . at this low concentration
the ic50 values for each drug were determined after 48 h by performing a sigmoidal regression on the concentration response curves .
cellular differentiation - ap3 ( 100 nm ) was added to the l. mexicana promastigote cultures in schneider 's insect medium ( ph 7.4 ) at 26c .
the cultures were then transferred to a growth chamber and cultured at 34c in the presence of 5% co2 . inactivated fbs ( 20% ) was added to the schneider 's insect medium ( ph 5.5 ) to allow differentiation of the promastigotes to the amastigote form .
after 24 h of incubation , the cultures were returned to the original temperature and ph conditions .
the cell cultures that were exposed to the same experimental conditions without drugs were used as controls .
the stage changes were observed under an inverted light microscope ( results not shown ) .
effect of anti - mt agents on l. mexicana promastigote proliferation - the antiproliferative activities of ap3 , chlorpromazine , taxol , tfp and rhizoxin were tested in vitro .
the ic50 values of these drugs were determined after 48 h of treatment ( table ) . of
the agents studied , ap3 was the most effective , strongly inhibiting the proliferation of l. mexicana promastigotes at nanomolar concentrations .
as observed by phase contrast microscopy , control cells were slender and spindle - shaped , each with a single flagellum ( fig .
the taxol - treated cells had a single flagellum and were pear - shaped or had shortened spindles ( fig .
the tfp - treated cells had a single motile flagellum and had spindle - shaped bodies with an occasional enlarged brilliant area at the anterior end ( fig .
the chlorpromazine - treated cells ( photographs not taken ) maintained a slender form with several cells presenting a brilliant spot at the anterior part of the cell body .
the cells that were treated with rhizoxin presented a morphologically mixed population of pear - shaped , round or spindle - shaped cells with slightly shortened lengths ; however , all rhizoxin - treated cells displayed a single flagellum ( fig .
in contrast , the ap3-treated cells displayed irregular or mostly round forms and were larger than the control cells .
furthermore , they had multiple actively beating flagella emerging from different parts of the cell body ( fig .
1e , f ) . in summary , except for the ap3-treated cells , the drug - treated cells presented normal or slightly altered morphology with a single flagellum .
light microscopy images of unfixed cells were taken after 48 h of growth in the presence of each drug at a concentration equivalent to the ic50 value .
table - antiproliferative effect of antimicrotubule drugs on leishmania mexicana promastigotesdrugsic50 ( m)taxol15chlorpromazine50trifluoperazine5rhizoxin22ansamitosin p30.092ic50 : 50% of inhibitory concentration .
parasites were cultured in the absence ( control ) ( a ) or in the presence of taxol at 15 m 50% of inhibitory concentration ( ic50 ) ( b ) or trifluoperazine at 5 m ( ic50 ) ( c ) or rhizoxin at 22 m ( ic50 ) ( d ) or ansamitocin p3 at 92.2 nm ( ic50 ) ( e - f ) during 48 h. light photographs of non fixed cells were taken using an electronic flash .
effect of anti - mt drugs on rvd in l. mexicana promastigotes under hypotonic stress - the drugs used in this study have shown strong antiproliferative effects on leishmania promastigotes .
based on these results , we next investigated the capacity of these drug - treated promastigotes to carry out rvd under hypotonic stress . when control cells were subjected to a reduction in osmolarity from 300 - 150 mosm
, they immediately swelled until they became quite rounded , but within a few minutes they began to shrink , reaching the same degree of motility and morphology observed at 300 mosm .
light - scattering experiments allowed us to follow the process of volume recovery by monitoring the a550 of the cell suspensions , as cell swelling leads to a decrease in the absorbance reading ( park et al .
the promastigotes were cultured for 48 h and the drugs were added at concentrations near the ic50 values .
the control cells and the drug - treated cells were centrifuged and resuspended in 300 mosm buffer . following a two - fold dilution of the isosmotic cell suspensions with distilled water ,
no differences in the lag time or rate of volume recovery were observed among control , chlorpromazine , taxol or tfp - treated cells ( fig .
2a ) ( and results not shown ) . the cells completed rvd in less than 5 min .
a decrease in absorbance was also observed in these cells 1 min post - treatment , but this decrease in absorbance was much more dramatic than that in the control cells .
volume recovery was not observed for the ap3-treated cells , whereas the rhizoxin - treated cells slowly returned to their original volume ( fig .
2regulatory volume decrease in leishmania mexicana promas tigotes after anti - microtubule ( mt ) drug treatment .
relative changes in cell volume of parasites cultured in the absence or presence of the drugs were followed by monitoring absorbance at 550 nm .
traces fol lowed by control , trifluoperazine ( tfp ) and taxol treated cells ( a ) and cells treated with rhizoxin and ansamitocin p3 ( ap3 ) ( b ) .
results are representatives of those obtained from five independent experiments and are expressed in arbitrary absorbance units .
effect of ap3 on the ultrastructure of l. mexicana promastigotes - light microscopy showed that ap3 dramatically affected the growth and morphology of l. mexicana promastigotes at nanomolar concentrations .
the unusual forms observed and the loss of the cells ' capacity to accomplish rvd led us to investigate the impact of ap3 treatment on the promastigote ultrastructure .
thin sections of cells were processed after 48 h of culture with 100 nm ap3 and were viewed by tem .
3a ) , the treated cells were round or amorphous with flagella - associated kinetoplasts ( kts ) in various cell positions .
the untreated cells displayed a rounded nucleus with a central prominent nucleolus and dense chromatin patches adhered to the internal nuclear membrane .
in contrast , the treated cells displayed anisotropic nuclei that appeared to sequester part of the cytoplasm ; moreover , the heterochromatin was arranged in dense reticular patches and the nucleolus was no longer visible .
the treated cells often displayed fragmented , condensed mitochondria accompanied by an increasing number of electron - transparent vesicles that occupied a considerable portion of the cytoplasm .
furthermore , many treated cells displayed multiple flagella emerging from one flagellar pocket ( fig .
abnormally elongated and duplicated kts were frequently observed both in association with and independent of flagella ( fig .
despite the dramatic changes in cell morphology in the presence of the drug , no changes in the corset mts or the distance between them were observed ( fig . 3f1 - 2 ) .
promastigotes after 48 h culture in schneider 's insect medium in the absence ( a ) or in the presence of 100 nm ap3 ( b - f ) .
rounded cells ( b - c ) with two distinct replicating kine toplasts ( kts ) were observed in different parts of the cell associated to flagella .
anisotropic nucleous ( n ) enclosing part of the cytoplasm was commonly visualized with chromatin arranged as a dense blocks .
cell with amorphous shape ( d ) presented branched condensed mitochondria ( m ) and an enlarged flagellar pocket containing five emerging flagella ( f ) .
multiple elongated dividing kts associated or not to basal bodies were frequently observed ( e1 - 4 ) .
subpellicular microtubules ( mts ) remain unaltered , as well as the distance between them ( f1 - 2 ) .
direct immunofluorescence of ap3-treated promastigotes and membrane - cytoskeleton complex - based on these findings , we used fluorescence microscopy to test whether leishmania mts remain unaltered following 48 h of promastigote culture with 100 nm ap3 , as has been observed by tem .
direct immunofluorescence of cells stained with fitc - conjugated anti - alpha tubulin showed a similar number and distribution of labelled mts in the slender , elongated control cells and the rounded treated parasites ( fig .
the fluorescence distribution was uniform within the parasite body and within the detergent - extracted cytoskeletons of the control ( fig .
4c ) and drug - treated cells , and mts were abundant in both preparations ( fig .
4tubulin fluorescent labelling of promastigotes and membrane cytoskeleton complex after ansamitocin p3 ( ap3 ) treatment . in slen der control cells ( a )
after ap3 treatment for 48 h , the labelling is observed in the rounded cell bodies and flagella .
tubulin labelling ( b ) of the membrane cytoskeleton complex prepared from normal ( c ) and treat ed cells ( d , e ) .
effect of ap3 on leishmania differentiation - in addition to its effect on promastigote cell division , ap3 also suppressed leishmania differentiation .
ap3 ( 100 nm ) was added to promastigotes cultured at 26c in schneider 's insect medium ( ph 7.4 ) and the cells were transferred to a growth chamber and cultured in medium with ph 5.5 at 35c in the presence of 5% co2 .
twenty - four hours later , the control cells had been transformed to the amastigote form , were oval shaped , had free flagella and were immobile .
the ap3-treated cells were of different shapes and sizes , had short flagella , formed cell aggregates and had a 40% cell death rate . after 24 h , the cells were returned to 26c and cultured in schneider 's insect medium ( ph 7.4 ) to allow differentiation from the amastigote to the promastigote form .
after 36 h , the untreated cells had completely reverted to the motile , slender promastigote form , whereas ap3 treatment completely inhibited differentiation to the promastigote form , resulting in predominantly large , non - motile cell aggregates .
the traditional approach to understanding the role of cytoskeletal components in rvd has been to use drugs that interfere with the cellular function of these components . here , we selected drugs that were previously reported to affect the proliferation of various leishmania species , suggesting that these drugs may act on the nuclear mts , the kts , the basal body or the assembly of new mts , which is necessary for cytokinesis . except for the two ansamitocin antibiotics , treatment with these drugs resulted only in slight changes in cell morphology .
for the most part , the cell populations remained slender or oval - shaped with one motile flagellum at the anterior end of the cell body .
this finding indicates that the antiproliferative effects of these drugs involved the inhibition of basal body replication , one of the earliest events of the cell cycle in leishmania and trypanosomatids ( robinson & gull 1991 , harmanton et al .
the drugs taxol , tfp and chlorpromazine ( results not shown ) did not alter promastigote rvd .
our findings were quite different for the drug rhizoxin : the antiproliferative action of this drug was associated with mixed morphological forms characterised by pear - shaped bodies or shortened spindles and a single flagellum .
these shape changes could account for the differences observed in the extent of cell swelling and in the rate of volume recovery under hypotonic conditions compared to the control cells .
the dose - dependent antiproliferative effect of ap3 observed at nanomolar concentrations , which was associated with profound changes in cell morphology and the inhibition of rvd , led us to focus on understanding the basis of this cell behaviour in response to ap3 .
our observation of large , rounded cells with numerous beating flagella throughout the cell body by light microscopy was supported by previous reports that electron micrographs showed several replicated flagellum - associated kts displaced throughout the cell .
in addition , the decreased proliferation of these cells and the electron microscopy data showing a single nucleus per cell with altered heterochromatin seemed to indicate an impairment in the assembly of the mitotic spindle and subpellicular mts following ap3 treatment .
these results are in agreement with those obtained in leishmania donovani promastigotes , in which ap3 induced the accumulation of cells in the g2 and m phases of the cell cycle .
this result is consistent with an anti - tubulin mechanism of action that generates 2 kt 1 nucleus cells and multi - kts cells ( havens et al . 2000 ) .
previous results also support our finding that drug treatment interferes with the polymerisation or assembly of new mts , which is necessary for body enlargement and the emergence of free flagella .
these functions enable the differentiation from the amastigote to the promastigote form through a mechanism similar to that involved in cilia regeneration in tetrahymena sp .
we also observed by electron microscopy that the integrity of the corset mts of ap3-treated promastigotes was preserved .
a similar observation has been reported for l. donovani promastigotes subjected to ap3 treatment under the same conditions ( havens et al . 2000 ) .
this finding was confirmed by labelling the mts of control and ap3-treated cells and their detergent - extracted cytoskeletons ( " ghosts " ) with an anti - tubulin antibody .
no differences were found in the distribution or fluorescence intensity of tubulin between the control and ap3-treated cells .
these data support the hypothesis that ap3 does not have a depolymerising effect on the cytoplasmic mts of l. mexicana promastigotes .
therefore , its ability to impair rvd , particularly during the recovery phase , can not be attributed to the instability of the subpellicular mt corset .
together , the results reported here suggest that drugs can induce strong antiproliferative effects without affecting volume regulation under hypotonic stress .
despite their antiproliferative effects , none of the drugs used in this study impeded rvd , except ap3 .
the amorphous or round shape of the ap3-treated cells differed from those of the cells treated with the other drugs , which presented only slight morphological changes ; they maintained elongated shapes and a single flagellum , indicating that they had not undergone basal body replication and separation .
it has been proposed that the rvd process in trypanosomatids involves a shape transition from an elongated to an almost spherical form .
this process depends on the medium osmolarity and is accompanied by the efflux of water , amino acids and osmolytes ( cosgrove & kessel 1958 , van rossum et al .
it has also been suggested that the linear subpellicular mts of elongated promastigotes of herpetomonas megaseliae undergo a spiralisation process upon phagocytosis in vitro , which results in the helicoidal arrangement that is found in round intracellular forms ( janovy et al .
1987 ) , indicating that the architectural rearrangement of mts might be a general process underlying shape transition in trypanosomatids and some euglenoids ( hoffman & bouck 1976 ) .
the forms assumed by the cells following an increase in volume are limited by ultrastructural constraints , as a constant distance must be maintained between the mts ( meyer & de souza 1976 ) . taking these findings into consideration
, a model has been proposed to account for the relationship between mt rearrangement , changes in cell volume and the transition from an elongated ( promastigote ) form to a spherical form . whereas some mts become linear , others assume a compensatory over - spiralised shape , allowing for a change in the cellular volume with little change in the cell surface area ( de andrade & de almeida 1980 ) . as we have shown in ap3-treated cells , various kts
consequently , mts are arranged parallel to various axes throughout the cells , resulting in mts with different directionalities .
this hypothesis suggests that during ap3 treatment , the process of mt spiralisation , followed by cell body torsion during hypotonic condition - induced shape change , becomes disorganised , asynchronous and ineffective .
therefore , the ap3-treated cells are not able to carry out the process of cell transformation that underlies rvd .
the successful search for new drugs for the treatment of leishmaniasis requires prior knowledge of the cellular biology and biochemistry of the parasites .
our results support the hypothesis that mts are viable therapeutic targets by demonstrating their important role in rvd in trypanosomatids .
the effect of ap3 is remarkable , particularly because it is effective at concentrations in the nanomolar range . | ### Summary:
: the trypanosomatid cytoskeleton is responsible for the parasite 's shape and it is modulated throughout the different stages of the parasite 's life cycle . when parasites are exposed to media with reduced osmolarity ,
they initially swell , but subsequently undergo compensatory shrinking referred to as regulatory volume decrease ( rvd ) .
we studied the effects of anti - microtubule ( mt ) drugs on the proliferation of leishmania mexicana promastigotes and their capacity to undergo rvd .
all of the drugs tested exerted antiproliferative effects of varying magnitudes [ ansamitocin p3 ( ap3 ) > trifluoperazine > taxol > rhizoxin > chlorpromazine ] .
no direct relationship was found between antiproliferative drug treatment and rvd .
similarly , mt stability was not affected by drug treatment .
ansamitocin p3 , which is effective at nanomolar concentrations , blocked amastigote - promastigote differentiation and was the only drug that impeded rvd , as measured by light dispersion .
ap3 induced 2 kinetoplasts ( kt ) 1 nucleus cells that had numerous flagella - associated kts throughout the cell .
these results suggest that the dramatic morphological changes induced by ap3 alter the spatial organisation and directionality of the mts that are necessary for the parasite 's hypotonic stress - induced shape change , as well as its recovery . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: to report a case of rhegmatogenous retinal detachment with a high risk of proliferative vitreoretinopathy ( pvr ) effectively treated with episcleral surgery and an intravitreal dexamethasone 0.7-mg implant .
a 35-year - old caucasian man with a macula - off rhegmatogenous subtotal retinal detachment that had persisted for 1 month in his myopic left eye presented several risk factors that could have led to the development of pvr after retinal detachment surgery .
he received an intravitreal dexamethasone 0.7-mg implant ( ozurdex ) after episcleral surgery to prevent this complication .
at least 9 months after surgery , no sign of pvr or pucker has developed in the treated eye .
visual acuity improved to 0.2 , the retina was attached and no complications were observed .
intravitreal dexamethasone 0.7-mg implant ( ozurdex ) could be considered as off - label treatment following episcleral surgery to prevent pvr .
proliferative vitreoretinopathy ( pvr ) is the most common cause of failure in retinal detachment surgery .
it can occur in untreated eyes or after pneumatic retinopexy , cryotherapy , laser retinopexy , scleral buckling or vitrectomy [ 2 , 3 ] .
pvr is a reparative process , similar to a keloid , initiated by full- or partial - thickness retinal breaks , retinopexy , and other types of retinal damage .
glial or rpe cells migrate to one or both surfaces of the retina , then migrate further and cover the posterior surface of the detached posterior hyaloid face . of all retinal detachment surgery cases , 510% develop pvr .
corticosteroids have been used as intravitreal injection after retinal detachment surgery as an adjunct to vitrectomy and silicone oil tamponade in treating pvr [ 4 , 5 ] . despite the potential benefits , intravitreal injection of triamcinolone acetonide
is associated with side effects , including glaucoma , cataracts , retinal detachment , and endophthalmitis .
recently , a sustained - release dexamethasone implant ( ozurdex ) proved to be effective for the treatment of macular edema secondary to a variety of underlying diseases with a potentially lower rate of adverse events [ 7 , 8 , 9 ] .
we report a case of rhegmatogenous retinal detachment with a high risk of pvr treated with episcleral surgery and an intravitreal dexamethasone 0.7-mg implant ( ozurdex ) .
a 35-year - old caucasian man presented with a macula - off rhegmatogenous subtotal retinal detachment extending 3 quadrants , sparing the inferior nasal quadrant , that had persisted for 1 month in his myopic left eye ( fig .
he had no history of previous vitreoretinal surgery , and his best corrected visual acuity was hand motion .
fifteen days before the beginning of the symptoms , he had had an ocular blunt trauma and presented with a large tear in the superior temporal quadrant extending 2 clock hours ( fig .
1b ) , and wrinkling of the edges of the retinal tear and the inner retinal surface , denoting a grade b pvr .
his medical history was unremarkable . on examination , the anterior segment was unremarkable and the intraocular pressure was normal .
he underwent scleral buckling surgery with circumferential silicone sponge and an encircling silicone band , and subretinal fluid drainage was employed .
at the end of the surgery , he received a single intravitreal injection , via pars plana , of dexamethasone 0.7 mg ( ozurdex ) as off - label treatment ( fig .
his condition has been stable for at least 9 months now , as seen on the last examination , with his best corrected visual acuity having improved to 0.2 and no sign of pvr or pucker having developed in the treated eye .
although pvr is the most common cause of failed repair of rhegmatogenous retinal detachment , risk factors for pvr are related to several well - known pre- , intra- , and postoperative clinical situations .
girard et al . identified a number of significant predictive variables : minor intra- or postoperative hemorrhage , grade a preoperative pvr , preoperative choroidal detachment , giant tears , air tamponade , detachment involving more than 2 quadrants , cumulative break area larger than 3 optic disks , postoperative choroidal detachment , signs of uveitis at initial examination , and grade b preoperative pvr .
young age , intraocular hemorrhage before or after surgery , use of air or sulfur hexafluoride ( sf6 ) , excessive cryotherapy , diathermy or photocoagulation , repeated surgical procedures , loss of vitreous during drainage of subretinal fluid , and the use of vitrectomy are also risk factors that increase the incidence of pvr .
various pharmacological agents have shown potential benefit in reducing postoperative pvr risk , including intravitreal low - molecular - weight heparin and 5-fluorouracil .
clinical reports have suggested that either systemic or intravitreal corticosteroids may be useful in the prevention of pvr .
this was mainly attributed to their attenuating effect on the blood - retinal barrier breakdown and their inhibiting effect on the proliferation of rpe cells and fibroblasts , which are thought to be transformed rpe cells , and on myofibroblasts responsible for the contractile properties of pvr membranes .
. demonstrated that adequate intraocular concentrations of dexamethasone at the time of surgery might reduce the blood - retinal barrier breakdown induced by the surgical trauma during cryotherapy , drainage of subretinal fluid , or intravitreal gas injection , and thereby decrease the incidence of pvr .
our patient presented several risk factors that could have led to the development of pvr after retinal detachment surgery , including young age , myopia , preoperative grade b pvr , long persistence of the retinal detachment , detachment involving more than 2 quadrants and large tear .
we therefore decided to inject an intravitreal dexamethasone 0.7-mg implant ( ozurdex ) after the surgery to prevent this complication .
at least 9 months after surgery , no sign of pvr or pucker had developed in the treated eye . to our knowledge , this is the first case described so far in the literature of an intravitreal dexamethasone implant inserted after episcleral surgery for rhegmatogenous retinal detachment to prevent possible pvr .
this is just a case report and it has several weaknesses , including the short - term follow - up .
further investigations are needed to demonstrate the role of the intravitreal dexamethasone 0.7-mg implant ( ozurdex ) in preventing pvr after episcleral surgery and to understand the long - term treatment outcomes .
intravitreal dexamethasone 0.7-mg implant ( ozurdex ) could be considered as off - label treatment after this kind of surgery .
| ### Summary:
: purposeto report a case of rhegmatogenous retinal detachment with a high risk of proliferative vitreoretinopathy ( pvr ) effectively treated with episcleral surgery and an intravitreal dexamethasone 0.7-mg implant.methodsa 35-year - old caucasian man with a macula - off rhegmatogenous subtotal retinal detachment that had persisted for 1 month in his myopic left eye presented several risk factors that could have led to the development of pvr after retinal detachment surgery .
his best corrected visual acuity was hand motion .
he received an intravitreal dexamethasone 0.7-mg implant ( ozurdex ) after episcleral surgery to prevent this complication.resultsat least 9 months after surgery , no sign of pvr or pucker has developed in the treated eye .
visual acuity improved to 0.2 , the retina was attached and no complications were observed.conclusionintravitreal dexamethasone 0.7-mg implant ( ozurdex ) could be considered as off - label treatment following episcleral surgery to prevent pvr . |
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: the heteromeric guanine nucleotide - binding proteins ( g - proteins ) are composed of , , and subunits .
the c825 t single - nucleotide polymorphism in the guanine nucleotide - binding protein beta polypeptide 3 ( gnb3 ) gene encoding for 3 subunit located on chromosome 12p13 has been found to be associated with essential hypertension and obesity . in recent literature , this polymorphism has also been associated with neurological and psychic conditions such as depression [ 36 ] , dementia , dependence , dyskinesia , and neurologically determined functional diseases [ 10 , 11 ] and with response to antidepressant or antipsychotic drugs .
nevertheless , all these studies have been performed on psychiatric patients or in subsets of selected subjects . to our knowledge ,
memory , language , and executive functions can be assessed and quantified by numeric scores .
a comprehensive neuropsychological battery of validated paper and pencil tests is also relevant for exploring focally the areas of cognitive functions putatively related to cognitive decline [ 1417 ] and is currently employed for assessing the cognitive ability .
it has also been found that poorly educated and elderly persons may show low scores at neuropsychological tests even without developing clinical evidence of dementia .
the aim of the present study was to verify whether , at a population level , the c825 t polymorphism of the gnb3 influenced the response to neuropsychological tests .
for this aim , a representative sample of a general population was used . only subjects aged 60 years
were included in the analysis , as it is known that the full expression of the genetic potential of gnb3 gene requires decades of life .
the study cohort was represented by unselected elderly subjects free from clinical dementia and from neurological and psychiatric diseases , randomly taken from the italian general population in the frame of the last evidences of genetic risk factors in the aged ( leogra ) study , whose protocol has been diffusely described elsewhere [ 2022 ] . in brief , all the adults of this geographic area were called ; 1,663 of them ( 73% ) adhered to the protocol , gave informed consent , and were recruited , screened and followed up for 10 years or until death at a special hospital unit . a cohort of 220 subjects aged 6095 years , chosen according to a random number list and representative of the whole population ,
weight was measured in kg with a mechanical device astra ( gima , gessate , italy ) , height in m. body mass index was calculated in kg / m from the weight / squared height ratio .
all subjects underwent a rose 's questionnaire concerning personal data , lifestyle , smoking , quality of life , and personal and familial anamnesis .
blood glucose was measured with the colorimetric method at 630 nm , plasma insulin with radioimmunoassay .
low - density - lipoprotein cholesterol was calculated with the friedlander algorithm . as a measure of insulin resistance
, the homeostasis model assessment index was calculated from homa - r = ( circulating insulin in u / ml ) ( fasting blood glucose in mmol / l)/22.5 .
all subjects underwent blood pressure measurements in triplicate by trained medical doctors by means of an automatic omron 705-it device ( omron europe , hoofddorp , netherlands ) ; to minimize the alert reaction , the average of the last two measurements was taken into account for the analysis of data .
subjects also underwent a standard electrocardiogram blindly codified according to the minnesota code , a 2d - echocardiogram recorded according to the american society of echocardiography and the penn convention ( megas device , esaote , firenze , italy ) and a spirometry ( pony spyrometer class i , type b , cosmed , rome , italy ) .
genomic dna was isolated from whole blood collected in ethylenediamine tetraacetic acid tubes using a blood dna prep plus spin - column system , according to the protocol provided by the manufacturer ( a&a biotechnology , gdansk , poland ) . for the determination of the c825 t polymorphism of the gnb3 gene ,
dna was extracted from cellular blood components by the salting - out method and amplified ; 80 ng of genomic dna were then subjected to 35 rounds of specific amplification using 5 tga ccc act tgc cac ccg tgc 3 ( sense primer ) and 5 gca gca gcc agg gct ggc 3 ( antisense primer ) .
after denaturation at 94c , dna was amplified using 0.5 u of taq polymerase at 94c for 1 minute , 61c for 1 minute , and 72c for 1 minute . after a final extension for 7 minutes
, polymerase chain reaction products were digested with bsedi ( fermentas ) , separated on 2.5% agarose gels , and visualized under uv illumination .
the undigested product ( tt genotype ) has a size of 268 bp ; complete digestion ( cc genotype ) results in bands of 116 and 152 bp , respectively .
the three genotypes were scored after running on a 2.5% agarose gel with 10 mg / ml ethidium bromide .
the evaluation consisted of a battery of validated tests relevant for exploring areas of cognitive functions potentially related to cognitive decline .
fourteen tests were selected in order to assess participant abilities in cognitive processing and grouped according to the function mainly involved : general functioning : mini mental state examination ( mmse ) and abstraction;memory tests : digit span , immediate and delayed memory , and memory with interference;executive tests involving one or more executive functions : overlapping figures , verbal fluency , trail making tests a and b ( tmts a and b);visuospatial abilities : spontaneous drawing , figure copying , and clock test.abstraction was studied by detecting logical abilities looking for a concept overordinating two terms .
general functioning : mini mental state examination ( mmse ) and abstraction ; memory tests : digit span , immediate and delayed memory , and memory with interference ; executive tests involving one or more executive functions : overlapping figures , verbal fluency , trail making tests a and b ( tmts a and b ) ; visuospatial abilities : spontaneous drawing , figure copying , and clock test .
digit span consisted of memorization and repetition of a series of numbers . long - term memory was assessed by tests of immediate and delayed prose memory presenting a prose passage containing 30 words and assessing immediate verbatim recalls followed by a 10 min delayed verbatim recall .
working memory was assessed by tests of memory with interference at 10 and 30 seconds ( mi10 , mi30 ) : the participants were requested to recall a consonant trigram after an interval delay during which they had to count backward starting from a 3-digit random number presented by the examiner immediately after the trigram . at the end of the interval delay of 10 and 30 seconds
verbal fluency was detected requiring participants to generate names from a specified category in a fixed period of time in 3 trials 60 seconds each . in the tmt
a subjects were required to connect with line progressive numbers , in the tmt b progressive numbers and letters [ 31 , 32 ] .
the overlapping figure was composed of 50 objects integrated into one perceptual unit [ 33 , 34 ] . in the clock test
the participant was instructed to draw a clock indicating 2 : 45 , setting the hands and numbers on the face so that a child could read them .
the instructions could be repeated until they were clearly understood , but once the subject began to draw , no further assistance was allowed .
the entire battery of tests was administered in a single session which took approximately two hours to complete .
the results of the neuropsychological battery were compared to the normative sample for italian subjects aged 60 years or over described by mondini et al . .
the mmse score was compared to the italian normative scores described by magni et al . .
the investigation conformed to the principles outlined in the declaration of helsinki and institutional guidelines and was approved by the local ethics committee . before the study and after consulting his / her own general practitioner , each subject accepted and signed an informed consent . a preliminary power analysis based on previous experience of the same laboratory [ 20 , 21 ] and on previous specific literature [ 311 ] showed that 98 cases overall and 20 cases in each group were sufficient to avoid -error with a desired statistical power of 0.08 and a probability level of 0.05 .
for this purpose , the ct and tt genotypes were considered together in a dominant genetic model for post hoc comparison , as the t allele has been found to exert a dominant effect . to compare c - carriers and tt subjects ,
a cohen 's d of 0.2 to 10.1 was considered , leading to a priori samples 36 cases per group .
continuous variables were expressed as mean standard deviation and compared between groups with analysis of covariance ; 95% confidence intervals were also shown for unadjusted values of the score of the neuropsychological tests across the c825 t polymorphism of gnb3 gene .
the same procedure was done in order to make items independent of each other in multiple regression .
the correlation with a continuous dependent variable was performed by stepwise multiple regression analysis , using both continuous and categorical items as independent variables ; generating odds ratios and 95% confidence intervals ( ci ) .
regression with categorical variables was performed logistically , also generating relative risks ( rr ) and 95% ci .
the general characteristics of the cohort are shown in table 1 . in table 2 ,
the mean values of the test scores are summarized and compared to the normative values for italian subjects of the same age and education . according to the c825 t polymorphism of the gnb3 gene ,
this distribution was in line with that of italian general population [ 2 , 21 , 35 ] and respected the hardy - weinberg equilibrium .
the multiple regression of neuropsychological tests with age and education across the c825 t polymorphism of gnb3 gene is shown in table 3 .
the c825 t polymorphism of gnb3 gene entered the model of analysis of variance for digit span ( f = 9.76 , p < 0.002 ) , immediate ( f = 5.56 , p < 0.02 ) and delayed prose memory ( f = 5.77 , p < 0.02 ) , mi10 ( f = 3.26 , p < 0.05 ) , verbal fluency ( f = 10.46 , p < 0.002 ) , and tmt a ( f = 6.04 , p < 0.01 ) and b ( f = 4.60 , p < 0.02 ) .
blood pressure or diagnosis of arterial hypertension , heart rate , body mass index or diagnosis of overweight , blood lipids or diagnosis of hypercholesterolaemia or hypertriglyceridaemia , blood glucose or diagnosis of diabetes , serum uric acid or diagnosis of hyperuricaemia , left ventricular mass index or diagnosis of left ventricular hypertrophy , history of cardiovascular disease , intake of ethanol or caffeine , and smoking did not influence either the response to the neuropsychological tests or their scores across the c825 t polymorphism of gnb3 gene .
mmse scored in average 26.1 3.9 ( ci 25.526.7 ) and was inversely related with age ( r = 0.23 , p < 0.0001 ) and not different across the c825 t polymorphism of the gnb3 gene either before or after adjustment for age and education ( figure 1 ) .
the rr for having a low performance at mmse ( score < 24 ) was 1.16 ( ci 1.081.23 ) in the whole cohort ; after further stratification , a significant rr was found in tt subjects ( 1.15 , ci 1.061.26 ) but not in those having cc or ct genotype .
the score of the abstraction task was related inversely with age ; direct regression with years of school was present both in the whole cohort ( table 3 ) and separately in the c - carriers ( r = 0.21 , p < 0.001 ) and in the tt subjects ( r = 0.28 , p < 0.02 ) .
even after adjustment for age and education , the score was not different across the c825 t polymorphism ( figure 1 ) . in our cohort of elderly subjects ,
the digit span was inversely related with age , every year of age producing 7% decrease of the score ( table 3 ) .
the age - adjusted digit span across the c825 t polymorphism of gnb3 gene is shown in figure 1 .
after stratification , any relationship of digit span with age was no longer detectable in tt subjects ( figure 3 ) .
the age - adjusted relative risk of having a performance < 6 at digit span was more than double for subjects carrying the tt polymorphism in comparison to the c - carriers ( figure 2 ) .
the digit span was not related with years of school in any of the polymorphisms .
the immediate prose memory score was inversely related with age in the entire cohort ( table 3 ) and selectively in cc and ct but not in tt subjects ( figure 3 ) .
the scores adjusted for age and education across the c825 t polymorphism are shown in figure 1 .
the delayed prose memory score was related inversely with age and directly with years of schooling ( table 3 ) .
regression with education was also present separately in the c - carriers ( r = 0.35 , p = 0.03 ) and in the tt subjects ( r = 0.70 , p = 0.02 ) , while that with age was lost in tt ( figure 3 ) .
the scores adjusted for age and education across the c825 t polymorphism of gnb3 gene are shown in figure 1 .
the score of mi10 was inversely related with age ( 17% for every year ) .
although the score was not different across the c825 t polymorphism ( table 3 and figure 1 ) , any regression with age was lost in ct and tt subjects .
the performance to this test was quite low , due to many subjects particularly carrying the tt polymorphism who scored 0 ( figure 3 ) .
the score of mi30 was directly related with education in the whole cohort ( table 3 ) and in the c - carriers ( r = 0.30 , p < 0.0001 ) but not in the tt subjects and was not different across the gnb3/c825 t polymorphism either before or after adjustment for age and education ( figure 1 ) .
inverse regression with age was found ( r = 0.07 , p < 0.01 ) , but disappeared after the introduction of the years of education .
the performance to this test was quite low due to many subjects particularly among the tt who scored 0 ( figure 3 ) .
the overlapping figure test was inversely related with age . after adjusting for age and education ,
its score was not different in c - carriers ( 17.4 9.6 ) and in tt ( 17.7 10.5 , p = 0.37 ) . in the c - carriers only , regression with years of education ( r = 0.92 , p < 0.001 ) not affecting the regression with age was observed .
the score of verbal fluency was inversely related with age , with exclusion of the tt subjects , where no correlation was detectable ( figure 4 ) .
it was also directly related with years of schooling in the c - carriers only ( r = 0.26 , p < 0.05 ) . after adjustment for age and education , it resulted to be 30% lower in tt subjects than in c - carriers ( figure 1 ) .
the tmts were directly related with age and limitedly to the c - carriers inversely related with years of schooling ( r = 2.28 , p = 0.04 ; r = 6.26 , p < 0.004 , resp . ) .
after adjustment for age and education , they were significantly higher in the tt subjects than in c - carriers ( figure 1 ) .
adding education did not abolish the regression of the tests with age and with the c825 t polymorphism of gnb3 gene .
the clock test score was inversely related to age , while no regression with genotype and education was found .
in this cohort of general population , the c825 t polymorphism of gnb3 gene resulted to be associated with cognitive functions .
age was the main covariable of the interaction between genotype and performance . schooling partially attenuated the effect of having unfavourable genotype .
all tests of memory but mi30 were inversely related with age , but this effect was not homogenous , being unequally distributed across the c825 t polymorphism of the gnb3 gene .
both short - term and long - term memory functions were c825 t dependent , being carried out with lower performance by the tt subjects ( digit 10.5% , ipm 19.5% , and dpm 9.7% ) , and in multiple logistic analysis the risk of having a limited performance at the digit span doubles in tt subjects .
not only this , but in tt subjects the performance of memory tests did not depend on age , probably indicating a genetically controlled acceleration of ageing .
education limited but did not abolish the effect of tt homozygosis on immediate and delayed prose memory , but not on digit span .
the tmt a and verbal fluency were influenced by the c825 t polymorphism of the gnb3 gene , being worse in the tt genotype ( an effect which was partially prevented by education ) , while the other executive functions ( tmt b , figure drawing and copying , and overlapping figure test ) were not different across the polymorphism .
verbal fluency worsened with increasing age in the c - carriers only , while the tt had a low score independently of age .
this indicates an influence of the c825 t polymorphism on the executive and visuospatial abilities . to our knowledge ,
no previous data are available in the literature about the interactions between cognitive tests and the c825 t polymorphism of gnb3 gene at a population level .
our results show that the tt homozygosis is unfavorable from a cognitive point of view .
this suggests that memory and executive functions may in part be inherited , while abstractive and visuospatial abilities are not .
the reason of lower cognitive ability in subjects with the tt homozygosis can only be object of speculation , due to paucity of data in literature .
subjects with the 825 t mutation have lower striatal dopamine transporter availability , which is in turn regulated by presynaptic g - protein coupled autoreceptors .
the striatal dopamine system has recently been considered to involve circuits that participate in the integration of cognitive activities and reward responses through the corticothalamic - basal gangliancortical loop .
the striatum is reduced in conditions associated with cognitive impairment , and a reduced striatal activity is actually associated with cognitive fatigue and with cognitive symptoms accompanying neurodegenerative conditions . in our cohort considered as a whole , the cognitive pattern was mildly worse than expected from italian normative data probably because the tt subjects were more represented in our cohort ( 15% ) than in the european population ( 8.18.4% ) [ 41 , 42 ] .
the unfavorable cardiovascular pattern which is typical of the leogra population [ 20 , 21 ] , and which in part derives in turn from the t mutation , could also account for impaired cognition .
a limitation of the study is represented by the fact that sample sizes were suboptimal , although they are representative of general population and ratified by power analysis . | ### Summary:
: to verify whether the c825 t polymorphism of the gnb3 influences the response to neuropsychological tests , mini - mental state examination , digit span ( ds ) , immediate and delayed prose memory , memory with interference at 10 and 30 seconds ( mi 10 and 30 ) , trail making tests ( tmts ) a and b , abstraction task , verbal fluency ( vf ) test , figure drawing and copying , overlapping figures test and clock test were performed in 220 elderly men and women free from clinical dementia and from neurological and psychiatric diseases randomly taken from the italian general population and analysed across the c825 t polymorphism .
the performance of ds , immediate and delayed prose memory , vf , and tmts was worse in subjects who were tt for the polymorphism in comparison to the c - carriers .
the performance of all tests declined with age . in the case of ds , immediate and delayed prose memory , mi 10 and vf , this trend was maintained in the c - carriers but not in tt . in the case of prose memory , of memory with interference , and of vf , schooling reduced the detrimental interaction between age and genotype .
the c825 t polymorphism of gnb3 gene therefore influences memory and verbal fluency , being additive to the effects of age and partially mitigated by schooling . |
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: peripartum cardiomyopathy ( ppcm ) is a form of idiopathic dilated cardiomyopathy that presents in women during the latter part of pregnancy or the first several months after delivery .
diagnostic criteria used to define ppcm include : ( 1 ) the development of heart failure ( hf ) in the last month of pregnancy or within 5 months postpartum ; ( 2 ) the absence of another identifiable cause of hf ; ( 3 ) the absence of recognizable heart disease prior to the last month of pregnancy ; and ( 4 ) left ventricular systolic dysfunction demonstrated by classical echocardiography criteria ( left ventricular ejection fraction < 45% , fractional shortening < 30% , or both , with or without an lv enddiastolic dimension > 2.7 cm / m body surface area ) .
the hf association of the european society of cardiology working group on ppcm recently expanded the definition to an idiopathic cardiomyopathy presenting with hf secondary to left ventricular systolic dysfunction towards the end of pregnancy or in the months following delivery , where no other cause of hf is found .
currently accepted risk factors associated with the development of ppcm include advanced maternal age , africanamerican race , chronic hypertension , preeclampsia , multiple gestations , and prolonged use of tocolytics .
prior studies have shown that the incidence of ppcm in the united states is between 1 in 1141 to 1 in 4350 live births ( mean 1 in 3186 live births ) . however , most of these data are from single center or single state / region studies and may not be representative of the national population .
ppcm is associated with important short and longterm complications , including acute pulmonary edema , cardiogenic shock requiring mechanical circulatory support , cardiopulmonary arrest secondary to hf or arrhythmias , thromboembolic complications , and death .
it is unclear if the incidence and outcomes of ppcm have remained constant or have changed over time .
the primary objective of this study was to determine the incidence and maternal complication rates of ppcm in a contemporary , realworld , nationwide population of hospitalized patients , as well as to examine the temporal trends in the incidence and outcomes of ppcm using the 20042011 nationwide inpatient sample ( nis ) databases .
the nis , sponsored by the agency for healthcare research and quality as a part of healthcare cost and utilization project ( hcup ) , is the largest publicly available allpayer inpatient care database in the united states .
it contains dischargelevel data from approximately 8 million hospital stays per year from about 1000 hospitals designed to approximate a 20% stratified sample of hospitals from 46 participating states ( in 2011 ) representing 97% of the us population .
criteria used for stratified sampling of hospitals include hospital ownership , patient volume , teaching status , urban or rural location , and geographic region .
inpatient stay records in the nis include clinical and resource use information available from discharge abstracts derived from statemandated hospital discharge reports .
this study was deemed exempt by the new york medical college institutional review board , because hcupnis is a public database with no personal identifying information .
data on annual number of live births in the united states were obtained from the centers for disease control and prevention ( cdc ) , national center for health statistics , vitalstats , or cdc wideranging online data for epidemiologic research ( wonder ) . from 2004 to 2011 , a total of 63 911 033 hospital records were included in the nis , corresponding to a national estimate of 313 736 891 hospital discharges in the united states .
a discharge record was classified as indicating ppcm if it included any of the international classification of diseases , ninth edition , clinical modification ( icd9cm ) codes 674.50 to 674.55 ( n=34 313 ) .
these icd9cm codes for ppcm were introduced in october 2003 and have been used in prior studies to accurately identify ppcm cases in administrative databases . for our study , we excluded women with ppcm aged < 15 or > 54 years ( n=94 ) due to small patient numbers at these extremes of ages and since cdc does not report data on annual number of live births in women > 54 years of age .
this gave us a final study cohort of 34 219 women aged 15 to 54 years with the diagnosis of ppcm .
for calculating ppcm incidence rates , live births in women aged < 15 years were excluded from the denominator .
we initially studied the temporal trends in ppcm incidence rates in the overall cohort as well as prespecified subgroups of age ( 15 to 19 , 20 to 29 , 30 to 39 , and 40 to 54 ) , race ( caucasian , africanamerican , hispanic , asian / pacific islander , and native american ) , census region ( northeast , midwest , south , and west ) , and comorbidities previously shown to increase the risk of ppcm ( chronic hypertension , pregnancyassociated hypertension , eclampsia , diabetes mellitus , tobacco use , multiparity , and multiple gestation ) .
similar to prior studies , we defined mae as either inhospital mortality or complications that can be life threatening or result in longterm morbidity .
these included cardiac arrest , heart transplant , mechanical circulatory support , acute pulmonary edema , thromboembolism , or implantable cardioverter defibrillator ( icd)/permanent pacemaker ( ppm ) implantation .
secondary outcomes included individual components of mae , as well as cardiogenic shock , and length of stay .
the icd9cm codes used to define each complication / outcome are provided in table 1 .
international classification of diseases , ninth edition , clinical modification ( icd9cm ) and clinical classifications software ( ccs ) codes used to identify comorbidities and outcomes htn indicates hypertension ; icd , implantable cardioverter defibrillator ; ppm , permanent pacemaker .
other comorbidities such as chronic hypertension , diabetes mellitus , alcohol abuse , anemia , rheumatoid arthritis / collagen vascular diseases , chronic pulmonary disease , coagulopathy , depression , drug abuse , hypothyroidism , liver disease , malignancy , fluid and electrolyte disorder , paralysis , other neurological disorders , obesity , peripheral vascular disease , psychoses , pulmonary circulation disorders , and chronic kidney disease were identified using the agency for healthcare research and quality comorbidity measures software .
baseline patient characteristics used included demographics ( age , race , primary expected payer , weekday versus weekend admission , median household income for patient 's zip code ) , and clinically relevant comorbidities ( chronic hypertension , diabetes mellitus , tobacco use , dyslipidemia , atrial fibrillation , alcohol abuse , anemia , rheumatoid arthritis / collagen vascular diseases , chronic pulmonary disease , coagulopathy , depression , drug abuse , hypothyroidism , liver disease , malignancy , fluid and electrolyte disorder , paralysis , other neurological disorders , obesity , peripheral vascular disease , psychoses , pulmonary circulation disorders , chronic kidney disease , pregnancyassociated hypertension , preeclampsia , eclampsia , antepartum hemorrhage , multiparity , and multiple gestation ) .
the icd9cm and/or clinical classifications software codes used to identify these comorbidities are provided in table 1 .
hospital characteristics such as hospital region ( northeast , midwest , south , and west ) , bed size ( small , medium , and large ) , location ( rural , urban ) , and teaching status were also included .
discharge weights provided in the nis were used to obtain national estimates of the annual number of ppcm cases , which were then used to calculate ppcm incidence rates .
standard error calculations for national estimates were made using the method recommended by the agency for healthcare research and quality .
we analyzed ppcm incidence rates for the overall cohort and for subgroups of age , race , census region , and selected comorbidities .
ppcm incidence rate/10 000 live births per calendar year was calculated with the numerator representing the weighted number of women aged 15 to 54 years with ppcm in that calendar year , and the denominator representing the number of live births in women aged 15 to 54 years for the given subgroup in the same year .
statistical significance of temporal trends in ppcm incidence was assessed using negative binomial regression of the number of ppcm cases per year , offset by the log of number of live births in the given year .
the nis database categorizes race / ethnicity as white ( caucasian ) , black ( africanamerican ) , hispanic , asian or pacific islander ,
other , or unkonwn / missing . in our study cohort , 750 ( 2.2% ) women were classified as having other race / ethnicity and 7318 ( 21.4% ) as unknown / missing race / ethnicity . due to the large proportion of other / unknown / missing race we used 2 approaches to calculate race / ethnicityspecific ppcm incidence rates . in the first approach we used only cases with complete information ( complete case analysis ) to calculate race
/ ethnicityspecific ppcm incidence rates for the prespecified subgroups ( caucasian , africanamerican , hispanic , asian / pacific islander , and native american ) . since it is not possible to determine which racial / ethnic groups
are included in the other category in the nis database and since there was no corresponding denominator in the cdc vitalstats birth data for this category , we did not calculate incidence rates for this subgroup .
next , we performed multiple imputation to impute missing values for race / ethnicity using the fully conditional specification ( fcs ) method ( an iterative markov chain monte carlo algorithm ) in spss 20.0 to create 5 complete data sets .
the pooled values were then used to calculate race / ethnicityspecific ppcm incidence rates . for multiple imputation , both
other and unknown / missing categories were considered as missing . to evaluate temporal changes in baseline characteristics
, we used the mantelhaenszel test of linear association for categorical variables and linear regression for continuous variables .
next , we analyzed the temporal trends in primary and secondary outcomes in women with ppcm . to assess whether outcomes have improved over time
our independent variable , calendar year , was initially entered as a continuous variable in the regression models to obtain unadjusted and adjusted odds ratios ( per year ) for the overall temporal trend in outcomes . to determine if there was a temporal variability from yeartoyear in the outcomes , we also evaluated calendar year as a categorical variable , with 2004 as the reference year .
the regression models adjusted for all demographics , hospital characteristics , and comorbidities listed in table 4 .
categorical variables are expressed as percentage and continuous variables as meanstandard deviation . or and 95% ci are used to report the results of logistic regression .
the nis , sponsored by the agency for healthcare research and quality as a part of healthcare cost and utilization project ( hcup ) , is the largest publicly available allpayer inpatient care database in the united states .
it contains dischargelevel data from approximately 8 million hospital stays per year from about 1000 hospitals designed to approximate a 20% stratified sample of hospitals from 46 participating states ( in 2011 ) representing 97% of the us population .
criteria used for stratified sampling of hospitals include hospital ownership , patient volume , teaching status , urban or rural location , and geographic region .
inpatient stay records in the nis include clinical and resource use information available from discharge abstracts derived from statemandated hospital discharge reports .
this study was deemed exempt by the new york medical college institutional review board , because hcupnis is a public database with no personal identifying information .
data on annual number of live births in the united states were obtained from the centers for disease control and prevention ( cdc ) , national center for health statistics , vitalstats , or cdc wideranging online data for epidemiologic research ( wonder ) .
from 2004 to 2011 , a total of 63 911 033 hospital records were included in the nis , corresponding to a national estimate of 313 736 891 hospital discharges in the united states .
a discharge record was classified as indicating ppcm if it included any of the international classification of diseases , ninth edition , clinical modification ( icd9cm ) codes 674.50 to 674.55 ( n=34 313 ) .
these icd9cm codes for ppcm were introduced in october 2003 and have been used in prior studies to accurately identify ppcm cases in administrative databases . for our study , we excluded women with ppcm aged < 15 or > 54 years ( n=94 ) due to small patient numbers at these extremes of ages and since cdc does not report data on annual number of live births in women > 54 years of age .
this gave us a final study cohort of 34 219 women aged 15 to 54 years with the diagnosis of ppcm .
for calculating ppcm incidence rates , live births in women aged < 15 years were excluded from the denominator .
we initially studied the temporal trends in ppcm incidence rates in the overall cohort as well as prespecified subgroups of age ( 15 to 19 , 20 to 29 , 30 to 39 , and 40 to 54 ) , race ( caucasian , africanamerican , hispanic , asian / pacific islander , and native american ) , census region ( northeast , midwest , south , and west ) , and comorbidities previously shown to increase the risk of ppcm ( chronic hypertension , pregnancyassociated hypertension , eclampsia , diabetes mellitus , tobacco use , multiparity , and multiple gestation ) .
similar to prior studies , we defined mae as either inhospital mortality or complications that can be life threatening or result in longterm morbidity .
these included cardiac arrest , heart transplant , mechanical circulatory support , acute pulmonary edema , thromboembolism , or implantable cardioverter defibrillator ( icd)/permanent pacemaker ( ppm ) implantation .
secondary outcomes included individual components of mae , as well as cardiogenic shock , and length of stay .
the icd9cm codes used to define each complication / outcome are provided in table 1 .
international classification of diseases , ninth edition , clinical modification ( icd9cm ) and clinical classifications software ( ccs ) codes used to identify comorbidities and outcomes htn indicates hypertension ; icd , implantable cardioverter defibrillator ; ppm , permanent pacemaker .
other comorbidities such as chronic hypertension , diabetes mellitus , alcohol abuse , anemia , rheumatoid arthritis / collagen vascular diseases , chronic pulmonary disease , coagulopathy , depression , drug abuse , hypothyroidism , liver disease , malignancy , fluid and electrolyte disorder , paralysis , other neurological disorders , obesity , peripheral vascular disease , psychoses , pulmonary circulation disorders , and chronic kidney disease were identified using the agency for healthcare research and quality comorbidity measures software .
baseline patient characteristics used included demographics ( age , race , primary expected payer , weekday versus weekend admission , median household income for patient 's zip code ) , and clinically relevant comorbidities ( chronic hypertension , diabetes mellitus , tobacco use , dyslipidemia , atrial fibrillation , alcohol abuse , anemia , rheumatoid arthritis / collagen vascular diseases , chronic pulmonary disease , coagulopathy , depression , drug abuse , hypothyroidism , liver disease , malignancy , fluid and electrolyte disorder , paralysis , other neurological disorders , obesity , peripheral vascular disease , psychoses , pulmonary circulation disorders , chronic kidney disease , pregnancyassociated hypertension , preeclampsia , eclampsia , antepartum hemorrhage , multiparity , and multiple gestation ) .
the icd9cm and/or clinical classifications software codes used to identify these comorbidities are provided in table 1 .
hospital characteristics such as hospital region ( northeast , midwest , south , and west ) , bed size ( small , medium , and large ) , location ( rural , urban ) , and teaching status were also included .
discharge weights provided in the nis were used to obtain national estimates of the annual number of ppcm cases , which were then used to calculate ppcm incidence rates .
standard error calculations for national estimates were made using the method recommended by the agency for healthcare research and quality .
we analyzed ppcm incidence rates for the overall cohort and for subgroups of age , race , census region , and selected comorbidities .
ppcm incidence rate/10 000 live births per calendar year was calculated with the numerator representing the weighted number of women aged 15 to 54 years with ppcm in that calendar year , and the denominator representing the number of live births in women aged 15 to 54 years for the given subgroup in the same year .
statistical significance of temporal trends in ppcm incidence was assessed using negative binomial regression of the number of ppcm cases per year , offset by the log of number of live births in the given year .
the nis database categorizes race / ethnicity as white ( caucasian ) , black ( africanamerican ) , hispanic , asian or pacific islander , native american ,
other , or unkonwn / missing . in our study cohort , 750 ( 2.2% ) women were classified as having other race / ethnicity and 7318 ( 21.4% ) as unknown / missing race / ethnicity . due to the large proportion of other / unknown / missing race we used 2 approaches to calculate race / ethnicityspecific ppcm incidence rates . in the first approach we used only cases with complete information ( complete case analysis ) to calculate race / ethnicityspecific ppcm incidence rates for the prespecified subgroups ( caucasian , africanamerican , hispanic , asian / pacific islander , and native american ) . since it is not possible to determine which racial / ethnic groups
are included in the other category in the nis database and since there was no corresponding denominator in the cdc vitalstats birth data for this category , we did not calculate incidence rates for this subgroup .
next , we performed multiple imputation to impute missing values for race / ethnicity using the fully conditional specification ( fcs ) method ( an iterative markov chain monte carlo algorithm ) in spss 20.0 to create 5 complete data sets .
the pooled values were then used to calculate race / ethnicityspecific ppcm incidence rates . for multiple imputation , both
other and unknown / missing categories were considered as missing . to evaluate temporal changes in baseline characteristics
, we used the mantelhaenszel test of linear association for categorical variables and linear regression for continuous variables .
next , we analyzed the temporal trends in primary and secondary outcomes in women with ppcm . to assess whether outcomes have improved over time
our independent variable , calendar year , was initially entered as a continuous variable in the regression models to obtain unadjusted and adjusted odds ratios ( per year ) for the overall temporal trend in outcomes . to determine if there was a temporal variability from yeartoyear in the outcomes , we also evaluated calendar year as a categorical variable , with 2004 as the reference year .
the regression models adjusted for all demographics , hospital characteristics , and comorbidities listed in table 4 .
categorical variables are expressed as percentage and continuous variables as meanstandard deviation . or and 95% ci are used to report the results of logistic regression .
between 2004 and 2011 , we identified 34 219 women aged 15 to 54 years with the diagnosis of ppcm . according to the cdc vitalstats
, there were a total of 33 118 166 live births in women aged 15 to 54 years during this period .
these data provide an overall ppcm rate of 10.3 ( 95% ci 10.2 to 10.4 ) per 10 000 live births ( or 1 in 968 live births ) ( table 2 ) . the incidence of ppcm increased with age and was highest among women aged 40 to 54 years ( 36.7 [ 95% ci 35.4 to 37.9 ] per 10 000 live births ) . when stratified according to race / ethnicity , ppcm incidence was lowest in hispanics and highest in african americans ( table 3 ) .
the incidence of ppcm was lowest in the west ( 6.5 [ 95% ci 6.3 to 6.7 ] per 10 000 live births ) and highest in the south ( 13.1 [ 95% ci 12.9 to 13.3 ] per 10 000 live births ) . when stratified according to the presence or absence of known risk factors for ppcm , women with chronic hypertension had the highest incidence of ppcm ( 267.5 [ 95% ci 262.3 to 272.7 ] per 10 000 live births ) .
similarly , the presence of eclampsia and diabetes mellitus were associated with a higher incidence of ppcm than their absence ( table 2 ) .
ppcm rates were similar in women with or without pregnancyassociated hypertension ( 10.1 [ 95% ci 9.5 to 10.6 ] and 10.4 [ 95% ci 10.3 to 10.5 ] per 10 000 live births , respectively ) .
interestingly , ppcm rates were higher in women who were nonsmokers , primipara , or had single gestation pregnancy ( table 2 ) .
temporal trends in peripartum cardiomyopathy incidence rate/10 000 live births stratified according to race / ethnicity n indicates the number of discharges across all years .
the numbers are weighted to reflect ppcm cases in the entire united states population . both
other and unknown / missing race categories were considered as missing for multiple imputation . mean age of the overall cohort was 30.37.0 years with 85.5% of women in the 20 to 39year age group ( table 4 ) .
african americans ( 47.5% ) constituted the highest proportion of patients with ppcm . the most common primary expected payer was medicaid ( 48.1% ) , and 38.6% of patients had median household income in the first quartile .
most common comorbidities in women with ppcm were anemia ( 30.5% ) , chronic hypertension ( 30.3% ) , fluid and electrolyte disorders ( 21.3% ) , obesity ( 13.9% ) , chronic pulmonary disease ( 11.6% ) , and preeclampsia ( 11.3% ) .
baseline demographics , hospital characteristics and comorbidities of patients with peripartum cardiomyopathy data are expressed as meanstandard deviation for continuous variables and number ( percentage ) for categorical variables .
ppcm incidence rate increased significantly from 8.5 per 10 000 live births ( 1 in 1181 live births ) in 2004 to 11.8 per 10 000 live births ( 1 in 849 live births ) in 2011 ( ptrend<0.001 ) ( figure 1 ) .
a similar increase in ppcm rates were seen in women 20 years of age , in all racial / ethnic groups ( except hispanics and asian / pacific islanders ) , and across all census regions in the united states during the study period ( ptrend<0.05 for all ) ( tables 2 and 3 ) . from 2004 to 2011 , there was a significant increase in the incidence of ppcm in patients with chronic hypertension ( 219.7 to 295.7 per 10 000 live births , ptrend<0.001 ) and diabetes mellitus ( 16.5 to 21.3 per 10 000 live births , ptrend<0.001 ) , but not in those with pregnancyassociated hypertension or eclampsia ( table 2 ) . as expected , based on current recommendations regarding avoidance of subsequent pregnancies after the development of ppcm ,
interestingly , women with multiple gestation pregnancies had a lower rate of ppcm ( table 2 ) .
ppcm incidence rate/10 000 live births per calendar year was calculated with the numerator representing the number of women aged 15 to 54 years with ppcm in that calendar year , and the denominator representing the number of live births in women aged 15 to 54 years for in the same calendar year .
error bars represent 95% confidence interval ( ci ) . in the overall cohort of patients with ppcm ,
mean age increased slightly from 30.17.0 in 2004 to 30.87.1 in 2011 ( ptrend<0.001 ) with a decrease in the proportion of women aged 15 to 19 years and a concurrent increase in the proportion of women aged 40 to 54 years ( table 4 ) . in patients with ppcm ,
there was a significant increase in the prevalence of chronic hypertension , diabetes mellitus , dyslipidemia , atrial fibrillation , anemia , rheumatoid arthritis / collagen vascular diseases , chronic pulmonary disease , coagulopathy , depression , drug abuse , hypothyroidism , liver disease , fluid , and electrolyte disorder , paralysis , other neurological disorders , obesity , peripheral vascular disease , psychoses , pulmonary circulation disorders , and chronic kidney disease ( ptrend<0.05 for all ) in women with ppcm during the study period ( table 4 ) .
on the other hand , the prevalence of tobacco use , pregnancyassociated hypertension , preeclampsia , and multiple gestations decreased significantly ( ptrend<0.05 for all ) during the past 8 years .
however , when adjusted for demographics , hospital characteristics , and comorbidities , no significant temporal trend was noted for this observed rise in mae ( adjusted or [ per year ] 0.99 , 95% ci 0.98 to 1.01 , ptrend=0.277 ) ( table 5 ) .
temporal trend in primary outcome ( major adverse events ) in patients with peripartum cardiomyopathy percentages indicate weighted results .
unadjusted and adjusted odds ratios per year and p values for trend were determined using logistic regression models evaluating calendar year as a continuous variable .
there was a statistically significant increase in inhospital mortality from 0.7% in 2004 to 1.8% in 2011 ( ptrend<0.001 ) , which persisted even after adjusting for possible confounding variables ( adjusted or [ per year ] 1.08 , 95% ci 1.02 to 1.14 , ptrend=0.006 ) ( table 6 ) .
the incidence of other complications was : cardiac arrest in 2.1% , heart transplant in 0.5% , mechanical circulatory support in 1.5% , acute pulmonary edema in 1.8% , icd /
no significant upward or downward trend was noted for most of these complications , except an increase in cardiogenic shock from 1.0% in 2004 to 4.0% in 2011 ( adjusted or [ per year ] 1.16 , 95% ci 1.11 to 1.21 , ptrend<0.001 ) , and mechanical circulatory support from 0.9% in 2004 to 2.2% in 2011 ( adjusted or [ per year ] 1.08 , 95% ci 1.03 to 1.14 , ptrend=0.002 ) ( table 6 ) .
the median length of stay for the overall cohort was 3 days ( interquartile range 2 to 6 days ) .
the proportion of patients with length of stay > 3 days decreased from 52.5% in 2004 to 49.1% in 2011 ( adjusted or [ per year ] 0.95 , 95% ci 0.94 to 0.96 , ptrend=0.006 ) ( table 6 ) .
temporal trends in secondary outcomes in patients with peripartum cardiomyopathy numbers in parenthesis represent 95% confidence interval ( ci ) .
los indicates length of stay ; or , odds ratio ; ppm , permanent pacemaker .
unadjusted and adjusted odds ratios per year and p values for trend were determined using logistic regression models evaluating calendar year as a continuous variable . adjusted or per year shown in italics
between 2004 and 2011 , we identified 34 219 women aged 15 to 54 years with the diagnosis of ppcm . according to the cdc vitalstats
, there were a total of 33 118 166 live births in women aged 15 to 54 years during this period .
these data provide an overall ppcm rate of 10.3 ( 95% ci 10.2 to 10.4 ) per 10 000 live births ( or 1 in 968 live births ) ( table 2 ) . the incidence of ppcm increased with age and was highest among women aged 40 to 54 years ( 36.7 [ 95% ci 35.4 to 37.9 ] per 10 000 live births ) . when stratified according to race / ethnicity , ppcm incidence was lowest in hispanics and highest in african americans ( table 3 ) .
the incidence of ppcm was lowest in the west ( 6.5 [ 95% ci 6.3 to 6.7 ] per 10 000 live births ) and highest in the south ( 13.1 [ 95% ci 12.9 to 13.3 ] per 10 000 live births ) . when stratified according to the presence or absence of known risk factors for ppcm , women with chronic hypertension had the highest incidence of ppcm ( 267.5 [ 95% ci 262.3 to 272.7 ] per 10 000 live births ) .
similarly , the presence of eclampsia and diabetes mellitus were associated with a higher incidence of ppcm than their absence ( table 2 ) .
ppcm rates were similar in women with or without pregnancyassociated hypertension ( 10.1 [ 95% ci 9.5 to 10.6 ] and 10.4 [ 95% ci 10.3 to 10.5 ] per 10 000 live births , respectively ) .
interestingly , ppcm rates were higher in women who were nonsmokers , primipara , or had single gestation pregnancy ( table 2 ) .
temporal trends in peripartum cardiomyopathy incidence rate/10 000 live births stratified according to race / ethnicity n indicates the number of discharges across all years .
the numbers are weighted to reflect ppcm cases in the entire united states population . both
other and unknown / missing race categories were considered as missing for multiple imputation . mean age of the overall cohort was 30.37.0 years with 85.5% of women in the 20 to 39year age group ( table 4 ) .
african americans ( 47.5% ) constituted the highest proportion of patients with ppcm . the most common primary expected payer was medicaid ( 48.1% ) , and 38.6% of patients had median household income in the first quartile .
most common comorbidities in women with ppcm were anemia ( 30.5% ) , chronic hypertension ( 30.3% ) , fluid and electrolyte disorders ( 21.3% ) , obesity ( 13.9% ) , chronic pulmonary disease ( 11.6% ) , and preeclampsia ( 11.3% ) .
baseline demographics , hospital characteristics and comorbidities of patients with peripartum cardiomyopathy data are expressed as meanstandard deviation for continuous variables and number ( percentage ) for categorical variables .
in the overall cohort , ppcm incidence rate increased significantly from 8.5 per 10 000 live births ( 1 in 1181 live births ) in 2004 to 11.8 per 10 000 live births ( 1 in 849 live births ) in 2011 ( ptrend<0.001 ) ( figure 1 ) .
a similar increase in ppcm rates were seen in women 20 years of age , in all racial / ethnic groups ( except hispanics and asian / pacific islanders ) , and across all census regions in the united states during the study period ( ptrend<0.05 for all ) ( tables 2 and 3 ) . from 2004 to 2011
, there was a significant increase in the incidence of ppcm in patients with chronic hypertension ( 219.7 to 295.7 per 10 000 live births , ptrend<0.001 ) and diabetes mellitus ( 16.5 to 21.3 per 10 000 live births , ptrend<0.001 ) , but not in those with pregnancyassociated hypertension or eclampsia ( table 2 ) .
as expected , based on current recommendations regarding avoidance of subsequent pregnancies after the development of ppcm , the rates of ppcm were higher among primipara women .
interestingly , women with multiple gestation pregnancies had a lower rate of ppcm ( table 2 ) .
ppcm incidence rate/10 000 live births per calendar year was calculated with the numerator representing the number of women aged 15 to 54 years with ppcm in that calendar year , and the denominator representing the number of live births in women aged 15 to 54 years for in the same calendar year .
error bars represent 95% confidence interval ( ci ) . in the overall cohort of patients with ppcm ,
mean age increased slightly from 30.17.0 in 2004 to 30.87.1 in 2011 ( ptrend<0.001 ) with a decrease in the proportion of women aged 15 to 19 years and a concurrent increase in the proportion of women aged 40 to 54 years ( table 4 ) . in patients with ppcm , the proportion of africanamerican women increased during the study period ( table 4 ) .
there was a significant increase in the prevalence of chronic hypertension , diabetes mellitus , dyslipidemia , atrial fibrillation , anemia , rheumatoid arthritis / collagen vascular diseases , chronic pulmonary disease , coagulopathy , depression , drug abuse , hypothyroidism , liver disease , fluid , and electrolyte disorder , paralysis , other neurological disorders , obesity , peripheral vascular disease , psychoses , pulmonary circulation disorders , and chronic kidney disease ( ptrend<0.05 for all ) in women with ppcm during the study period ( table 4 ) .
on the other hand , the prevalence of tobacco use , pregnancyassociated hypertension , preeclampsia , and multiple gestations decreased significantly ( ptrend<0.05 for all ) during the past 8 years .
our primary outcome of interest was maternal mae . in the overall cohort , mae occurred in 4633 ( 13.5% ) patients .
however , when adjusted for demographics , hospital characteristics , and comorbidities , no significant temporal trend was noted for this observed rise in mae ( adjusted or [ per year ] 0.99 , 95% ci 0.98 to 1.01 , ptrend=0.277 ) ( table 5 ) .
temporal trend in primary outcome ( major adverse events ) in patients with peripartum cardiomyopathy percentages indicate weighted results .
unadjusted and adjusted odds ratios per year and p values for trend were determined using logistic regression models evaluating calendar year as a continuous variable .
there was a statistically significant increase in inhospital mortality from 0.7% in 2004 to 1.8% in 2011 ( ptrend<0.001 ) , which persisted even after adjusting for possible confounding variables ( adjusted or [ per year ] 1.08 , 95% ci 1.02 to 1.14 , ptrend=0.006 ) ( table 6 ) .
the incidence of other complications was : cardiac arrest in 2.1% , heart transplant in 0.5% , mechanical circulatory support in 1.5% , acute pulmonary edema in 1.8% , icd / ppm placement in 2.9% , and cardiogenic shock in 2.6% ( table 6 ) .
no significant upward or downward trend was noted for most of these complications , except an increase in cardiogenic shock from 1.0% in 2004 to 4.0% in 2011 ( adjusted or [ per year ] 1.16 , 95% ci 1.11 to 1.21 , ptrend<0.001 ) , and mechanical circulatory support from 0.9% in 2004 to 2.2% in 2011 ( adjusted or [ per year ] 1.08 , 95% ci 1.03 to 1.14 , ptrend=0.002 ) ( table 6 ) .
the median length of stay for the overall cohort was 3 days ( interquartile range 2 to 6 days ) .
the proportion of patients with length of stay > 3 days decreased from 52.5% in 2004 to 49.1% in 2011 ( adjusted or [ per year ] 0.95 , 95% ci 0.94 to 0.96 , ptrend=0.006 ) ( table 6 ) .
temporal trends in secondary outcomes in patients with peripartum cardiomyopathy numbers in parenthesis represent 95% confidence interval ( ci ) .
los indicates length of stay ; or , odds ratio ; ppm , permanent pacemaker .
unadjusted and adjusted odds ratios per year and p values for trend were determined using logistic regression models evaluating calendar year as a continuous variable . adjusted or per year shown in italics
in this study , we report the overall incidence rate as well as the temporal trends in incidence and outcomes of ppcm using a contemporary , realworld , nationwide , allpayer database of hospitalized patients in the united states . to our knowledge , this is the largest cohort of ppcm patients described to date .
the major findings of our study are : ( 1 ) the overall ppcm rate during 20042011 was 10.3 per 10 000 live births ( 1 in 968 live births ) ; ( 2 ) ppcm incidence rate increased from 8.5 per 10 000 live births ( 1 in 1181 live births ) in 2004 to 11.8 per 10 000 live births ( 1 in 849 live births ) in 2011 ; ( 3 ) the temporal increase in ppcm incidence rates was seen in all women 20 years of age , in all racial / ethnic groups ( except hispanics and asian / pacific islanders ) , and across all census regions in the united states ; ( 4 ) the overall frequency of maternal mae was 13.5% and remained stable during the study period ; ( 5 ) inhospital mortality in women with ppcm was 1.3% and increased slightly during the past 8 years ; and ( 6 ) the most common complication in women with ppcm was thromboembolism ( 6.6% ) .
ppcm is an idiopathic dilated cardiomyopathy that presents in women during the latter part of pregnancy or the first several months after delivery .
prior studies have reported the incidence of ppcm in the united states to be between 1 in 1141 to 1 in 4350 live births ( mean 1 in 3186 live births ) .
mielniczuk et al analyzed data on 16 296 ppcm cases among 3.6 million patient discharges included in the 19902002 national hospital discharge survey ( nhds ) and reported an overall ppcm incidence of 1 in 3189 live births .
there was a nonsignificant trend for an increase in ppcm incidence over time , from 1 in 4350 live births in 19901993 to 1 in 2229 live births in 20002002 . despite changes in coding for ppcm , our current results from the 2004 to 2011 nis databases are consistent with , and extend these prior findings from the nhds . in the present study , ppcm incidence rate increased significantly from 1 in 1181 live births in 2004 to 1 in 849 live births in 2011 .
compared with prior reports , the higher incidence of ppcm in the present study could be due to differences in case selection ( clinical data versus icd9cm codes , delivering only versus all ppcm ) , time period under consideration , and more selective ( single center / region ) versus nationally representative population .
there are several potential explanations for the observed increase in ppcm incidence over the past 8 years .
first , it is possible that the actual incidence of ppcm has increased over time , which may be related to increasing maternal age , and increasing prevalence of established risk factors for ppcm ( eg , chronic hypertension , preeclampsia / eclampsia , and multiple births ) , as well as other cardiovascular comorbidities ( eg , obesity and diabetes mellitus ) in pregnant women . similar to previous studies , we observed a higher incidence of ppcm in women with known risk factors such as chronic hypertension , eclampsia , and diabetes mellitus .
we also found an increasing trend in several cardiovascular risk factors in women with ppcm ( table 4 ) .
second , the increase in incidence could be attributable to expansion of the definition of ppcm to extend the time frame during which this condition may occur or be diagnosed .
third , our data may also be explained , at least in part , by increasing recognition and diagnosis of ppcm .
lastly , differences in case finding / coding during the study period can not be completely eliminated . in our study , maternal mae occurred in 13.5% of women with ppcm .
there was no significant change in mae rate during the study period . in a retrospective review and analysis of clinical data of 182 patients with ppcm ,
goland et al reported mae in 25% of patients over a 6year followup , with 84% of mae occurring during the first year .
kao et al recently reported inhospital outcomes in 535 delivering women with ppcm from 6 states .
maternal mae ( defined as inhospital death , cardiac arrest , heart transplant , or mechanical circulatory support ) occurred in 6.7% of women with ppcm .
these differences in the observed rates of mae are likely due to differences in patient selection criteria ( clinical data versus icd9cm codes , delivering only versus all ppcm ) , definition of mae as well as individual outcomes , and the followup period . reported mortality rates for ppcm in the united states have varied widely with lower rates observed in more recent studies .
brar et al concluded that mortality rates associated with ppcm were lower than initially reported at 2.5% over a mean followup of 4.7 years , and goland et al reported a mortality rate of 7% over an 8year followup .
because the hospital records are deidentified , the nis does not contain postdischarge data on longterm mortality .
therefore , in the present study , we were able to determine only the inhospital mortality rate , which was 1.3% in the overall cohort and showed a small but statistically significant increase over the past 8 years .
our results are consistent with the previously reported inhospital mortality rate of 1.36% to 2.05% in the nhds .
felker et al , in a retrospective review of cardiomyopathies of various etiologies , reported markedly lower mortality in ppcm compared with idiopathic and other forms of cardiomyopathies . compared with an overall inhospital mortality rate of 1.3% in ppcm patients in the present study ,
inhospital mortality rate in all hf patients ( not including ppcm ) was significantly higher at 3.8% in a recent analysis of the 20012009 nis databases , suggesting that mortality is lower in ppcm as compared with other causes of hf .
there was no significant change in the rates of most complications , except for cardiogenic shock , which increased from 1.0% in 2004 to 4.0% in 2011 .
the increase in cardiogenic shock could be explained , at least partially , by early recognition and increasing diagnosis of this condition as well as changes in coding over the years .
alternatively , this may represent a true increase in cardiogenic shock since there was a parallel increase seen in the utilization of mechanical circulatory support during the study period .
recent data from the interagency registry for mechanically assisted circulatory support ( intermacs ) registry showed that women with ppcm who receive mechanical circulatory support have a better survival than women with nonppcm , with a 2year survival of 83% and a recovery rate of 6% in ppcm group . reported rates of cardiac transplantation in women with ppcm in the united states have ranged from 0% to 11% .
the low rates of heart transplantation ( 0.5% ) seen in our study are likely due to lack of availability of data on longterm followup .
dedicated registries such as the european society of cardiology eurobservational registry on ppcm with systematic , prospective data collection are needed to confirm the incidence as well as to determine the longterm outcomes of ppcm .
it is possible that we may have overestimated the incidence of ppcm due to the following reasons .
first , due to the deidentified nature of the nis database , we were unable to identify the number of unique admissions ( ie , if the same patient was readmitted more than once during the same pregnancy ) .
similarly some women might have had more than one pregnancy . however , because healthcare providers often discourage subsequent pregnancies in ppcm patients due to concerns of recurrent / persistent cardiac dysfunction and poorer outcomes including mortality , and because only 0.3% of women in our cohort were multipara , multiple pregnancies in the same patient likely had a small effect on the ppcm incidence rates .
second , whereas conditions such as chronic hypertension , preeclampsia , diabetes mellitus , or anemia are established risk factors for ppcm , these conditions can themselves cause hf , especially during the postpartum period .
individual patient charts / records and echocardiographic measurements were not available to verify the accuracy of the icd9cm codes used to identify women with ppcm and to definitely exclude other causes of hf .
the current ppcm icd9cm codes introduced in 2003 , although more specific than coding used in previous studies using administrative data , have not been validated systematically . nonetheless , these icd9cm codes have been used previously by other investigators to accurately identify patients with ppcm in administrative databases .
other limitations include lack of clinical information ( eg , vital signs , medications , laboratory results ) , which is available in clinical trials or registries . some of these limitations may be partially counterbalanced by the large sample size and absence of reporting bias due to selective participation of specialized centers in trials and/or registries .
it is possible that we may have overestimated the incidence of ppcm due to the following reasons .
first , due to the deidentified nature of the nis database , we were unable to identify the number of unique admissions ( ie , if the same patient was readmitted more than once during the same pregnancy ) .
similarly some women might have had more than one pregnancy . however , because healthcare providers often discourage subsequent pregnancies in ppcm patients due to concerns of recurrent / persistent cardiac dysfunction and poorer outcomes including mortality , and because only 0.3% of women in our cohort were multipara , multiple pregnancies in the same patient likely had a small effect on the ppcm incidence rates .
second , whereas conditions such as chronic hypertension , preeclampsia , diabetes mellitus , or anemia are established risk factors for ppcm , these conditions can themselves cause hf , especially during the postpartum period .
individual patient charts / records and echocardiographic measurements were not available to verify the accuracy of the icd9cm codes used to identify women with ppcm and to definitely exclude other causes of hf .
the current ppcm icd9cm codes introduced in 2003 , although more specific than coding used in previous studies using administrative data , have not been validated systematically . nonetheless , these icd9cm codes have been used previously by other investigators to accurately identify patients with ppcm in administrative databases .
other limitations include lack of clinical information ( eg , vital signs , medications , laboratory results ) , which is available in clinical trials or registries
. some of these limitations may be partially counterbalanced by the large sample size and absence of reporting bias due to selective participation of specialized centers in trials and/or registries .
this analysis of the 20042011 nis databases describes the temporal trends in incidence and outcomes of ppcm in the united states .
we find an increase in the incidence of ppcm over the past 8 years in the overall cohort , as well as in all women 20 years of age , in all racial / ethnic groups ( except hispanics and asian / pacific islanders ) , and across all census regions in the united states .
inhospital mortality in women with ppcm was 1.3% and increased only slightly during the study period .
the frequency of most complications remained unchanged , except an increase in cardiogenic shock and use of mechanical circulatory support .
further study of the mechanisms underlying these adverse trends in the incidence and outcomes of ppcm are warranted .
strategies to reduce the incidence and improve outcomes of ppcm should focus on controlling obesity , hypertension , diabetes mellitus , and promoting lifestyle modifications in women of childbearing age group . | ### Summary:
: backgroundthe reported incidence of peripartum cardiomyopathy ( ppcm ) in the united states varies widely .
furthermore , limited information is available on the temporal trends in incidence and outcomes of ppcm.methods and resultswe queried the 20042011 nationwide inpatient sample databases to identify all women aged 15 to 54 years with the diagnosis of ppcm .
temporal trends in incidence ( per 10 000 live births ) , maternal major adverse events ( mae ; defined as inhospital mortality , cardiac arrest , heart transplant , mechanical circulatory support , acute pulmonary edema , thromboembolism , or implantable cardioverter defibrillator / permanent pacemaker implantation ) , cardiogenic shock , and mean length of stay were analyzed . from 2004 to 2011 , we identified 34 219 women aged 15 to 54 years with ppcm .
the overall ppcm rate was 10.3 per 10 000 ( or 1 in 968 ) live births .
ppcm incidence increased from 8.5 to 11.8 per 10 000 live births ( ptrend<0.001 ) over the past 8 years .
mae occurred in 13.5% of patients .
there was no temporal change in mae rate , except a small increase in inhospital mortality and mechanical circulatory support ( ptrend<0.05 ) .
cardiogenic shock increased from 1.0% in 2004 to 4.0% in 2011 ( ptrend<0.001 ) .
mean length of stay decreased during the study period.conclusionfrom 2004 to 2011 , the incidence of ppcm has increased in the united states .
maternal mae rates overall have remained unchanged while cardiogenic shock , utilization of mechanical circulatory support , and inhospital mortality have increased during the study period .
further study of the mechanisms underlying these adverse trends in the incidence and outcomes of ppcm are warranted . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: glaucomatous optic neuropathy is characterized by the progressive loss of retinal ganglion cells and their respective axons , which comprise the retinal nerve fiber layer ( rnfl ) . with regard to the evaluation of glaucoma , optical coherence tomography ( oct )
provides reproducible quantitative measurements of rnfl around the optic nerve head ( onh ) and in the macular region [ 37 ] .
rnfl assessment is important because rnfl often precedes functional changes detected by perimetry [ 817 ] .
conversely , the onh size is not constant among individuals , with an interindividual variability of approximately 1 : 7 in a normal caucasian population .
the onh size is reportedly a possible risk factor for glaucomatous optic nerve damage [ 2024 ] .
however , several groups have reported no difference in susceptibility between patients with a large disc and those with a small disc [ 2530 ] .
furthermore , the influence of the onh size on circumpapillary rnfl ( cprnfl ) thickness is not fully understood .
several studies have found that the cprnfl thickness measured at a fixed diameter is positively correlated with the optic disc area [ 31 , 32 ] .
the implication was that the number of nerve fibers in cprnfl depends on the disc area and that it might be possible to decrease the variations in the measured cprnfl thickness if the scan diameter was adjusted according to the disc diameter , although this possibility was not supported by huang et al . in normal healthy subjects .
to the best of our knowledge , there are no published clinical reports evaluating the relationship between the onh size and the macular ganglion cell complex ( mgcc ) thickness in eyes with primary open angle glaucoma ( poag ) .
the aim of the present study was to evaluate the relationships among the onh area , mgcc thickness , and cprnfl thickness measured using spectral - domain oct ( sd - oct ) and visual field defects in patients with poag .
this retrospective study was performed in adherence with the guidelines of the declaration of helsinki and was approved by the institutional review board ( number 13 - 29 ) of toho university , ohashi medical center , tokyo , japan . because of the retrospective nature of this study , the requirement for written informed consent was waived .
we retrospectively reviewed the medical records of 90 eyes of 90 patients with poag , including normal tension glaucoma ( ntg ) .
the patients underwent sd - oct for measurement of the onh area , rim area , mgcc thickness , and cprnfl thickness and standard automated perimetry ( sap ) within a 3-month period at our outpatient clinic between may 2008 and september 2012 .
sap was performed using the humphrey field analyzer ( humphrey - zeiss systems , dublin , ca , usa ) with the 30 - 2 swedish interactive threshold algorithm ( sita ) .
the visual field tests were considered reliable when the fixation losses were < 20% and the false - positive and false - negative rates were < 25% . the mean deviation ( md )
the ophthalmological procedures included visual acuity testing with refraction , slit - lamp biomicroscopy , gonioscopy , goldmann applanation tonometry for the measurement of intraocular pressure ( iop ) , and dilated stereoscopic fundus examination .
the diagnostic criteria for poag used in this study included the following : normal open anterior chamber angles on slit - lamp biomicroscopy and gonioscopy , presence of a glaucomatous onh on stereoscopy with corresponding visual field defects , a best - corrected visual acuity of at least 20/25 , refractive errors in the spherical equivalent ( se ) not exceeding 6 or + 3 diopters , and a cylindrical correction of less than 3 diopters .
a visual field defect was defined as the presence of three or more significant ( p < 0.05 ) , contiguous nonedge points with at least one point at p < 0.01 level in the pattern deviation plot , along with grading outside the normal limits on the glaucoma hemifield test ( ght ) .
exclusion criteria included the following : a history of intraocular surgery , the presence of intraocular diseases such as diabetic retinopathy or age - related macular degeneration that affect image quality or visual field test results , and a history of systemic diseases such as intracranial disease and/or a history of steroid use , both of which affect iop and visual field test results .
sd - oct was performed using the rtvue-100 system ( software version 4.0 , optovue inc . ,
sd - oct uses a scanning laser diode that emits a beam with a wavelength of 840 10 nm and provides images of ocular microstructures . for all participants
, measurements were obtained from both regions on the same day . in this study ,
this protocol includes one horizontal scan and 15 vertical scans that cover 7 mm region . to achieve the best possible coverage within the temporal region ,
the gcc protocol centered the scan 1 mm temporal to the center of the fovea . during the total scanning period ,
15,000 data points were captured within 0.6 s. the gcc scan creates a 6 mm map , which corresponds to approximately 20 on the visual field map . the onh protocol used in this study was designed to measure the cprnfl thickness and onh parameters . the total time required to acquire
a single scan was 0.55 s. using the sd - oct - generated fundus image ( video baseline protocol ) , we were able to manually trace the onh contour . using the onh scanning protocol software , the rnfl thickness
was automatically measured at a 3.45 mm diameter around the center of the optic disc .
in addition , the onh protocol includes 12 radial scans measuring 3.4 mm in length ( 452 a - scans each ) and six concentric ring scans measuring 2.54.0 mm ( 587775 a - scans each ) , all of which are centered around the optic disc contour line automated by the three - dimensional topographic image protocol .
the areas between the a - scans were interpolated and various parameters generated to describe the optic disc .
data with signal strength index ( ssi ) values of < 30 were excluded . in this study , the following factors were included for analysis : age , refraction , the onh area , the rim area , the mgcc thickness , the cprnfl thickness , and md .
spearman 's rank correlation coefficient was used to evaluate the relationship of the onh area with other factors .
multiple regression analysis was used to evaluate the relationship of the mgcc thickness or cprnfl thickness with age , refraction , the rim area , md , and the onh area , as well as the relationship of md with the mgcc thickness , the cprnfl thickness , age , refraction , the rim area , and the onh area .
all statistical analyses were performed using spss statistical software ( version 20.0 , spss inc . ,
data are expressed as means standard deviations ( sds ) , and a p value of < 0.05 was considered statistically significant .
in the present study , we assessed 90 patients with poag , including 66 patients ( 73.3% ) with ntg .
table 2 shows spearman 's rank correlation coefficients between the onh area and age , refraction , the rim area , the mgcc thickness , the cprnfl thickness , and md . three factors were significantly correlated with the onh area : refraction ( r = 0.362 , p < 0.001 ) , the mgcc thickness ( r = 0.225 , p = 0.033 ) , and the cprnfl thickness ( r = 0.253 , p = 0.016 ) .
tables 3 and 4 show the results of multiple regression analysis , wherein the mgcc thickness or cprnfl thickness was used as the dependent variable and age , refraction , the onh area , the rim area , and md were used as explanatory variables .
consequently , the onh area ( slope = 4.283 m / mm , a standard partial regression coefficient ( ) = 0.241 , 95% confidence interval ( ci ) = 0.907 to 7.659 , and p = 0.014 ) , the rim area ( slope = 10.329 m / mm , = 0.386 , 95% ci = 5.309 to 15.350 , and p < 0.001 ) , and md ( slope = 0.569 m / db , = 0.207 , 95% ci = 0.051 to 1.087 , and p = 0.032 ) were selected as significant contributing factors to explain the mgcc thickness .
similarly , the onh area ( slope = 4.394 m / mm , = 0.231 , 95% ci = 0.865 to 7.922 , and p = 0.015 ) , the rim area ( slope = 11.079 m / mm , = 0.386 , 95% ci = 5.832 to 16.327 , and p < 0.001 ) , and md ( slope = 0.658 m / db , = 0.223 , 95% ci = 0.117 to 1.200 , and p = 0.019 ) were selected as significant contributing factors to explain the cprnfl thickness .
table 5 shows the results of multiple regression analysis , wherein md was used as the dependent variable and age , refraction , the onh area , the rim area , the mgcc thickness , and the cprnfl thickness were used as explanatory variables .
in the present study , the onh area was significantly correlated with refraction , the mgcc thickness , and the cprnfl thickness . with regard to significant correlation between the onh area and refraction
, we acknowledge that this finding was a consequence of the lack of correction for refraction magnification , which is characteristic of the rtvue-100 system .
a previous study reported that refraction was correlated with the cprnfl thickness and mgcc thickness and that rnfl thickness and onh parameters including disc size measured by sd - oct are subject to influence from the axial length in normal eyes .
the present study , which does not measure the axial length , included 90 patients , with 49 eyes exhibiting refractive errors of less than 3 diopters .
therefore , it is expected that eyes with an axial length longer than the standard were predominant . accordingly
, the fact that a significantly positive correlation was observed between the disc size and refraction indicates the possibility of influence from the axial length , as shown in previous studies [ 34 , 35 ] . in the future , it is necessary to consider influence of refraction and axial length when we will evaluate the parameters measured using sd - oct . with regard to the relationship between the onh area and the mgcc thickness or cprnfl thickness
, several studies evaluated the mgcc thickness and cprnfl thickness and reported that the onh area affects the ability to detect glaucoma [ 36 , 37 ] .
significant correlations between the rim area and the mgcc thickness and between md and the mgcc thickness have been also reported [ 38 , 39 ] . however
, no study has ever mentioned a correlation between the onh area and mgcc thickness . according to table 3
, we found a significant correlation between the mgcc thickness and the onh area , the rim area , and md using multiple regression analysis .
although the underlying reason remains unclear , our study suggests that the smaller onh area , the thinner mgcc thickness .
similarly , as shown in table 4 , we found a significant correlation between the cprnfl thickness and the onh area , the rim area , and md using multiple regression analysis .
several studies have reported the correlation between the onh area and the cprnfl thickness [ 31 , 32 , 35 ] .
savini et al . found a positive correlation between the optic disc size and the 360 rnfl thickness , both of which were measured using oct .
histological studies also reported a positive correlation between the disc size and number of nerve fibers [ 40 , 41 ] .
however , huang et al . reported no significant association between the rnfl thickness and the optic disc area .
the authors stated that previous publications showing such an association may have been biased by the effects of the axial length on fundus image magnification .
several other investigators found that the cprnfl thickness was correlated with the axial length and refractive error [ 35 , 4244 ] . in the present study , even though patients with high myopia were excluded , a significant correlation was still observed between the onh area and cprnfl thickness using multiple regression analysis . considering the findings of former studies and our results , the onh area may be related to the cprnfl thickness . on the other hand , multiple regression analyses using the mgcc thickness and cprnfl thickness as objective variables showed corresponding coefficients of determination ( r ) values of 0.297 ( table 3 ) and 0.333 ( table 4 ) , respectively .
however , the fact that the disc area was shown as a significant variable in multiple regression analyses including all available factors proves that the disc area itself may affect the mgcc thickness and cprnfl thickness .
this study also examined the effects of the onh area , rim area , mgcc thickness , and cprnfl thickness on visual field defects ; no factor was identified as a significant contributing factor to explain md ( table 5 ) .
this result supported those of a meta - analysis that concluded that the onh area was not an independent risk factor for glaucoma .
previous studies reported significant correlation between the mgcc thickness , cprnfl thickness , and md [ 39 , 46 ] . in most former studies , the enrolled subjects suffered from glaucoma with a mean md value of less than 7.0 db from sap .
this means that the subjects in our current study had glaucoma with relatively earlier stages than those in former studies , and these factors may not be well correlated with the visual field defects .
moreover , it was reported that gcc thickness was most useful parameter to evaluate structure and function within the central 10 of macula in glaucoma
. therefore we should further investigate by adding the sita 10 - 2 program to visual field tests in future studies .
the strength of the present study was that it revealed , for the first time to our knowledge , the relationship between the disc size and the mgcc thickness .
first , because of the retrospective study design , there may be a possible bias in the selection of subjects .
fourth , it remains unclear whether our findings will be beneficial for glaucoma practice in the future . in conclusion
, the results of the present study suggest that the onh area is significantly positive correlated with the mgcc thickness and cprnfl thickness .
furthermore , the onh area is selected as significant contributing factor to explain the mgcc thickness and cprnfl thicknesses .
therefore , the disc size itself may affect the mgcc thickness and cprnfl thickness in eyes with poag .
further studies are required to provide further evidence supporting our findings and confirm the magnitude of the influence of the disc area on the mgcc thickness and cprnfl thickness . | ### Summary:
: purpose . to evaluate the relationships among the optic nerve head ( onh ) area , macular ganglion cell complex ( mgcc ) thickness , circumpapillary retinal nerve fiber layer ( cprnfl ) thickness , and visual field defects in patients with primary open angle glaucoma ( poag )
. methods . this retrospective study included 90 eyes of 90 patients with poag .
the onh area , rim area , mgcc thickness , and cprnfl thickness were measured using optical coherence tomography .
mean deviation ( md ) was measured using standard automated perimetry . the relationships among clinical factors including age , refraction , the onh area , the rim area , the mgcc thickness , the cprnfl thickness , and md
were evaluated using correlation coefficients and multiple regression analyses .
results .
the significant correlation of the onh area with refraction ( r = 0.362 , p < 0.001 ) , the mgcc thickness ( r = 0.225 , p = 0.033 ) , and the cprnfl thickness ( r = 0.253 , p = 0.016 ) was found .
multiple regression analysis showed that the onh area , rim area , and md were selected as significant contributing factors to explain the mgcc thickness and cprnfl thickness .
no factor was selected to explain md .
conclusions . the onh area , in other words , the disc size itself may affect the mgcc thickness and cprnfl thickness in poag patients . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: spontaneous perinephric hematoma ( sph ) is rare and has been described in association with conditions , such as angiomyolipomata , renal cell carcinoma , renal artery aneurysm and metastatic renal melanoma [ 1 , 2 ] .
due to varied clinical presentation , without any specific cause , the diagnosis of sph is a clinical dilemma .
imaging plays a significant role in the diagnosis and management of this potentially lethal entity [ 3 , 4 ] . since the clinical picture of sph varies considerably depending on the degree and duration of bleeding , ruling out other etiologies which can be managed
a 34-year - old african - american male presented to the emergency department ( ed ) with a sudden onset of left flank pain , radiating to the left testicle .
spontaneous splenic capsular bleeding requiring splenectomy had occurred 3 months previously , and he was being followed by hematology for post - splenectomy thrombocytosis . of note , platelets were 513 k/l ( normal 150400 k/l ) on admission and patient was not on aspirin .
a computed tomography scan of the abdomen performed in the ed showed a large left perinephric hematoma ( figure 1 ) .
a left renal angiogram showed active extravasation from the lower pole branch of the left renal artery , and gelfoam embolization was performed which resulted in the resolution of bleeding .
acute renal failure developed within 1 day of admission , due to a combination of renal artery embolization and contrast administration ( pre - embolization creatinine 1.33 mg / dl and post - embolization creatinine 1.85 mg / dl with peak of 2.28 mg / dl ) .
it resolved rapidly over the ensuing 48 h. subsequently , the patient developed spontaneous bilateral subconjunctival hemorrhage on day 2 of his hospitalization , followed by gastrointestinal bleeding .
his relevant laboratory studies showed the following : prolonged prothrombin time ( pt ) with international normalized ratio of 1.4 ( normal 0.81.2 ) and a mixing study showed complete correction and moderately low factor x levels of 52 ( normal 73163 ) .
protein studies : both serum and urine immunofixation electrophoresis showed an abnormal homogenous band in the lambda region ( table 1 ) .
igg = immunoglobulin g ; iga = immunoglobulin a ; igm = immunoglobulin m ; mg / dl = milligrams per deciliter a bone marrow biopsy demonstrated mild plasmacytosis ( 10% of total cellularity ) with lambda light chain restriction and aberrant cyclin d1 expression , consistent with the presence of a plasma cell neoplasm .
in addition , amyloid deposition was noted in the surrounding soft tissue , as supported by the presence of congophilic material with apple - green birefringence under polarized light ( figures 24 ) .
stomach , duodenal and splenectomy specimen biopsies also demonstrated amyloid deposition , confirmed by congo red staining .
immunohistochemical stains showed the amyloid to be negative for amyloid a and transthyretin and positive for lambda light chain , consistent with amyloid light chain ( al)-type amyloid ( figure 4 ) .
however , when associated with abnormal coagulation studies or bleeding at multiple sites , amyloidosis should be considered because of its protean systemic manifestations and potential response to chemotherapy . of the major causes reported , tumors accounted for 5763% of cases ( benign in 2433% and malignant in 3033% ) , vascular disease ( such as polyarteritis nodosa ) for 1826% and infection for 710% .
. acquired hemostatic abnormalities , including factor xa deficiency , hyperfibrinolysis and platelet dysfunction , can be regarded as important pathogenetic factors in al amyloidosis .
this patient s bleeding diathesis likely resulted from perivascular / vascular amyloid deposition and factor xa deficiency [ 57 ] .
pathology demonstrated amyloid infiltration of blood vessels , which leads to amyloid angiopathy with increased vascular wall fragility and impaired vasoconstriction . in the literature , the mechanisms attributed to factor x deficiency in the setting of amylodosis is thought to be due to binding of factor xa on amyloid fibrils primarily in the liver and spleen and decreased synthesis of coagulation factors in patients with advanced liver disease due to the infiltrative process .
this phenomenon of abnormal bleeding was noted in 94 cases ( 28% ) , and the coagulation screen was abnormal in 172 cases ( 51% ) .
the most common abnormalities were prolongation of the thrombin time ( 108 cases , 32% ) and pt : 82 cases , 24% .
of 368 consecutive patients with systemic al amyloidosis evaluated at boston medical center , 32 patients ( 8.7% ) had factor x levels < 50% of normal .
eighteen of these patients ( 56% ) had bleeding complications , which were more frequent and severe in the 12 patients < 25% of normal ; two episodes were fatal .
he underwent cardiac evaluation including cardiac magnetic resonance imaging 1 month after chemotherapy was initiated .
the results were consistent with cardiac involvement by amyloidosis ( ejection fraction = 63% , basal inferoseptum 1.9 cm ) .
notably , however , serum troponin t levels had been normal , and the previous elevation of b - type natriuretic peptide had resolved .
serum - free light chains normalized 4 weeks after initiation of chemotherapy , and the last serum and urine immunofixation studies demonstrated no detectable monoclonal protein , consistent with ongoing hematological remission .
improvement in his plasma factor x level suggested a reduction in the overall abundance of amyloid .
thus , aggressive treatment of the underlying plasma cell neoplasm in al amyloidosis can lead to the amelioration of amyloid - related factor x deficiency [ 6 , 8 ] .
because there is no factor x concentrate available , fresh frozen plasma would have to be used for bleeding episodes until the underlying disease can be controlled .
such temporary replacement is feasible although the response may be short - lived because of amyloid binding to factor x after factor x enters the circulation .
the main question is whether we could improve his long - term prognosis through high - dose chemotherapy and autologous stem cell transplantation given the cardiac involvement , a particularly fatal complication of amyloidosis .
the largest series to date included 312 patients who received high - dose melphalan ( 100200 mg / m ) followed by autologous stem cell transplantation . patients with cardiac amyloid ( ejection fraction of 40% )
had worse survival than those without cardiac involvement ( 1.6 versus 6.4 years , respectively ) , but 10 of 58 patients did show a cardiac response ( decrease of 2 mm in a thickened intraventricular septum ) following transplantation . it is conceivable that treatment with newer agents such as bortezomib may produce long - term outcomes that compare favorably with transplant - based approaches , but currently available data are insufficient to reach this conclusion . for these reasons , we favored pursuing an autologous stem cell transplant as part of his management strategy . | ### Summary:
: spontaneous perinephric hematoma ( sph ) is a rare entity whose diagnosis is challenging because of its varied clinical presentation and lack of any specific etiology .
we report a 34-year - old african - american male who presented with left flank pain and was found to have a large left perinephric hematoma , in the setting of undiagnosed al amylodosis .
the case illustrates that while a sph due to the vascular angiopathy of amyloid is rare , when amyloidosis is associated with abnormal coagulation studies or bleeding at multiple sites , it should be considered because of its protean systemic manifestations and potential response to chemotherapy . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: improving maternal health is one of the eight millennium development goals1 stated by the united nations ( un ) .
therefore , all un member states have been implementing policies directed toward promoting health during pregnancy and the postnatal period .
although recent efforts have led to a decrease in maternal mortality by half during the last decade,2 the un indicates that more efforts are needed to achieve this millennium development goal by 2015.3 in this regard , improving maternal health and decreasing morbidity and mortality from induced abortions are key endeavors for all un state members , especially for developing countries.4 clearly , accurate epidemiological information about maternal mortality is crucial before proposing evidence - based public health interventions or legal policies regarding women s health worldwide , as well as for accurately evaluating the effects of such interventions .
study of actual statistics surrounding induced abortion is difficult in countries where it is restricted ; therefore , researchers employ various epidemiologic methodologies to yield estimations around empirically plausible figures . given their inherent estimative nature , constant challenge and adjustment of the methodologies are mandatory steps to ensure valid , accurate , and reliable abortion estimates .
in addition , another important issue to adequately gauge the influence of abortion on maternal health is to consider the relative contribution of other causes of maternal morbidity and mortality .
thus , promoting the use of standardized methodologies along with an appropriate epidemiologic interpretation of the international classification of diseases ( icd ) are two key endeavors that researchers should follow and policy makers should demand before intervening at a population level .
this information becomes particularly important when resources are limited and adequate priorities must be defined to efficiently allocate such resources to improve maternal health , especially in low and middle income developing countries .
when attempting to evaluate how maternal health may be influenced by abortion at a population level , three major epidemiological indicators are frequently taken into account : maternal mortality ratio ( mmr ) : mmr is the acknowledged indicator for assessing maternal health worldwide.5 it is obtained by dividing the number of maternal deaths ( ie , female deaths during pregnancy , childbirth , and puerperium ) by the number of live births in a given year . the reliability of this indicator will depend on the quality of the registry of vital statistics of each country , which has greatly improved during the last two decades for several latin american countries.4,6 number of abortions : many countries which have a liberal abortion law exhibit fairly accessible abortion statistics . however , most latin american countries restrict induced abortion by law .
abortion mortality ratio or abortion - related mortality ratio ( amr ) : amr is similar to mmr , and is calculated as the number of maternal deaths due to abortion divided by the number of live births in a given year .
amr is subject to some ambiguity , depending on what is included in the term deaths due to abortion .
this ambiguity becomes evident when some researchers include maternal deaths from spontaneous as well as induced abortions to calculate amr .
lack of a univocal definition of amr complicates interpretation of this indicator , especially when assessing maternal mortality associated with induced abortion . the present work aimed to reevaluate estimation methods employed to obtain abortion figures in countries exhibiting restrictive abortion laws and to re - analyze figures of maternal mortality and abortion mortality presented in recent studies conducted in mexico as an illustrative case of major discrepancies regarding maternal health indicators in the context of latin america .
a recent report published this year in the lancet7 presented global estimates of induced abortion for different regions , concluding that no progress was observed in latin america over the last decade .
abortion estimations were based on a combination of in - hospital statistics and surveys of subjective opinion over a limited number of individuals and health institutions rather than on actual vital statistic data , eliciting largely overestimated figures.715 the validity of this methodology is seriously questioned in a recent review.1619 the methodological approach first considers the estimation of the losses from spontaneous and induced abortions from the opinion of subjects who work in health institutions through a survey entitled health facilities survey .
respondents are asked to remember the total number of women who received post - abortion care in the average month and in the past month.8 in a second step , another opinion survey entitled health professionals survey , is applied to non - randomly selected individuals who are unrelated to the health facilities selected for the former survey .
the health professionals survey is used to estimate an expansive multiplier ( x3 , x4 , x5 , etc ) , which is then applied to the numbers obtained by the health facilities survey.715 in consequence , these estimation methods are subjective in nature and extremely subject to selection and recall bias , making them questionable instruments even when evaluating the general impression of abortion in a particular territory . in contrast , estimates using actual demographical data , fertility rates , observed live births , abortion mortality rates , and known abortion rates from standard populations , or complete abortion hospital discharges might be more accurate and objective than estimates based on opinion surveys .
moreover , significant overestimation of abortion figures715 prompts unnecessary alarm in public opinion , especially when an allegation of no progress over time
is made , and when such an allegation disregards the actual progress on maternal health observed in most latin american countries.6,20 methodological problems can be illustrated when comparing indirect abortion estimates based on opinion surveys and actual abortion figures in the federal district of mexico ( mexico df ) , the only mexican state where elective abortion is legal ( since april 24 , 2007 ) . for 2006 , using a combination of in - hospital statistics and opinion surveys , juarez et al11 estimated between 725,070 and 1,024,424 induced abortions for the whole country of mexico , and between 137,145 and 194,875 induced abortions for mexico df .
nevertheless , the total number of elective induced abortions registered the year after making abortion legal in this mexican state was 10,137.21 in fact , the figure of legally induced abortions carried out in the five cumulative years from april 2007 until april 2012 ( ie , a period of time probably long enough to replace illegal abortion with legal procedures in mexico df ) was 78,544 ; which is nearly 50% of the original estimate by the authors for only a single year.23 during that period , induced abortions showed a clear upward trend year - by - year in mexico df , from 10,137 in 2008 to 14,390 in 2011 ( figure 1).21 moreover , juarez et al have recently conducted another study12 insisting on the use of the same methodology and showing figures of induced abortion overestimated by approximately 1000% for 2009 ( ie , estimating 122,455 induced abortions instead of the actual figure of 12,221 for mexico df in 2009)21 despite the existence of epidemiological surveillance on this matter by an independent non - governmental agency.21 we acknowledge that underreporting of legal abortions may limit the reliability of estimations based on actual records in mexico df .
nevertheless , mexican health authorities have been actively working towards decreasing the underreporting of maternal mortality statistics which , at least in terms of mmr , have decreased to a negligible percentage since 2003.22,23 even if such efforts have yet to be translated into a decrease in the potential underreporting of legal abortion records in mexico df , especially within the private sector , the figures proposed by juarez et al11,12 would still be overestimated .
for instance , speculatively assuming an underreporting of 1- to 3-fold , the figure proposed by these authors11,12 would be overestimated by 2.5 to 5 times . in this scenario ,
conclusions about induced abortion rates drawn by studies based mainly on opinion surveys715 appear to be inconsistent due to substantial overestimation in countries with restrictive abortion legislation.16,19 in strict scientific rigor , they fail to reflect reality and therefore , an in - depth revision of the methodologies utilized by different authors715 is warranted before drawing any definitive conclusion about actual abortion trends in mexico and other latin american countries where abortion is restricted by law .
a recent study by schiavon et al22 analyzed how maternal mortality and abortion - related deaths have evolved during the last two decades in mexico ( 19902008 ) .
the authors concluded that mexico has failed to show progress in abortion- related mortality during the last 20 years , particularly due to illegal abortions .
schiavon et al22 use indicators that group maternal deaths by causes of diverse etiology considering the numerator for amr as deaths by all pregnancies with abortive outcome in the two more recent versions of the icd ( icd-10 codes o00o08 and icd-9 codes 630639).22 this group includes causes of death ranging from abnormal products of conception to unspecified , and other abortions .
table 1 shows the most frequent clinical use of icd codes for classifying deaths for pregnancies with an abortive outcome . in this regard , it is important to point out that icd codes unrelated to induced abortion ( such as hydatidiform mole or ectopic pregnancy ) should not be included in the assessment of abortion mortality , particularly when the focus of the study is to address the influence of illegal abortion on maternal health .
for example , if one wanted to measure the deleterious effects of alcoholism on the liver , one would want an indicator specific to alcoholism .
if that indicator instead included liver damage caused by fulminant hepatitis , wilson s disease , and drug - related liver damage , then the specific damage attributable to alcohol would be obscured .
similarly , if one wants to determine mortality from induced abortion , then deaths from other causes ( such as hydatidiform mole or ectopic pregnancy ) should be excluded .
the authors use indirect estimations of live births instead of the readily available statistics of actual observed live births for the period of study .
in addition , discrepancies in data found in the sources employed by the authors , most likely due to an honest mistake , led to an almost 35% overestimation of mmr and amr for this country ( tables 2 and 3 ) .
not infrequently , it is thought that criminalization of abortion may lead to underreporting by misclassification of maternal deaths suspected to be the result of an illegally induced abortion.26 as discussed elsewhere,6 however , this is unlikely and becomes irrelevant when considering the existence of icd-10 codes of death due to other abortion ( o05 ) , unspecified abortion ( o06 ) , and failed attempted abortion ( o07 ) , especially in countries with adequate civil registration of vital data and active epidemiological surveillance of maternal deaths . in fact , usage of these icd codes allows safeguarding of both professional and patient confidentiality when physicians suspect an illegal abortion.25 moreover , nowadays in most countries , physicians are subject to legal sanctions if they are found guilty of distorting or misclassifying actual causes of death.6 thus , the reliability of mortality ratios associated with abortion is likely to depend on the registry quality of each territory studied . in this regard , it is important to note that civil registration in mexico is characterized as virtually complete by the un and the world health organization ( who ) , with good attribution of causes of death .
in fact , mexico is classified in list a ( complete vital statistic records ) regarding the registry of maternal death causes , along with 64 other countries in the last report of global maternal mortality by who.2 interestingly , mexico exhibits a large historical registry of maternal mortality , similar to the case of chile , the country with the lowest mmr in latin america .
a recent time series study between 1957 and 2009 conducted in chile showed a reduction of mmr of 93.8% , from 270.7 to 16.9 maternal deaths per 100,000 live births.6 the historical trend of mmr in mexico , as reflected in the mexican official records27 of maternal deaths between 1957 and 2010 , resembles the case of chile ( figure 2 ) . between these years ,
overall mmr in mexico decreased by 82.7% ( from 216.6 to 37.5 deaths per 100,000 live births ) , with a specific decrease of 30.6% between 1990 and 2010 ( from 54.0 to 37.5 deaths per 100,000 live births ) . with the exception of hemorrhage ,
the current profile of mexican maternal mortality is similar to the case of chile , dominated by gestational hypertension and eclampsia , and indirect causes of death , such as cardiovascular disease , diabetes , and other pre - existing chronic conditions ( figure 3 ) . of note ,
approximately 98% of the current maternal deaths are related to causes other than induced abortion in both countries .
as stated above , amr as assessed by schiavon et al22 includes codes o00o08 ( or the corresponding icd-9 codes 630639 ) .
nevertheless , selection of adequate icd codes that illustrate maternal mortality related to abortion would require excluding those of ectopic pregnancy ( o00 of icd-10 or 633 of icd-9 ) , hydatidiform mole ( o01 of icd-10 or 630 of icd-9 ) , and other abnormal products of conception ( o02 of icd-10 or 631632 of icd-9 ) .
if the focus of a study is the impact of induced abortion on maternal health , then the icd-10 code o03 ( or the corresponding icd-9 code 634 ) should also be excluded , as it refers to maternal deaths due to spontaneous abortion .
icd-10 code o04 ( medical abortion ) and icd-9 code 635 ( legal abortion ) clearly refer to maternal deaths associated with medical / legally induced abortions .
however , deaths classified as other abortion ( o05 of icd-10 ) , unspecified abortion ( o06 of icd-10 and 637 of icd-9 ) , and failed attempted abortion ( o07 of icd-10 and 638 of icd-9 ) are somewhat obscure and mixed in their interpretation and use ( table 1 ) .
their ambiguity allows physicians to classify maternal deaths that do not fall in the previously described categories .
therefore , such codes may be employed in countries exhibiting restrictive abortion laws to classify maternal deaths suspected to be the result of complications arising from illegal abortion . in consequence ,
a more suitable indicator of maternal deaths related to induced abortions should include only the icd-10 codes associated with medical abortion ( o04 ) , other abortion ( o05 ) , unspecified abortion ( o06 ) , and failed attempted abortion ( o07 ) , excluding all other causes of maternal death ending in abortion .
interestingly , no maternal deaths have been registered in mexico as caused by failed attempted abortion ( o07 ) during the last decade ( table 4 ) .
in addition , registry of other specific causes with an abortive outcome , such as ectopic pregnancy , abnormal products of conception , and other well - defined pathological conditions , are virtually complete in this country .
therefore , deaths by unspecified abortion ( o06 ) , along with other abortion ( o05 ) , become the most likely indicators to approach complications due to illegal abortions for the particular case of mexico . when taking this into consideration
, even though the amr shown by schiavon et al22 displays discrete changes between 1990 and 2008 , unspecified abortion ( o06 ) combined with other abortion ( o05 ) between 2002 and 2008 shows a downward trend , with a 22.9% overall decrease from 1.44 to 1.10 deaths per 100,000 live births ( figure 4 ) .
this observation further supports the notion that the apparent lack of progress in abortion - related maternal mortality in mexico is likely to be related to causes other than unspecified abortion ( o06 ) and other abortion ( o05 ) , and therefore seems to be unrelated to illegal induced abortion .
further analysis reveals interesting changes in the absolute number and relative contribution of some abortion - related causes of maternal deaths which occurred between 2002 and 2008 ( table 4 and figure 5 ) .
first , increases in the relative contribution of spontaneous abortion ( o03 , from 1.0% to 10.3% ) and other abortion ( o05 , from 3.1% to 7.7% ) were observed ; second , almost no changes were apparent in the relative contribution of medical abortion ( o04 , from 1.0% to 1.3% ) .
finally , decreases were observed in the relative contribution of pathological conditions ( o00o02 , from 57.7% to 51.3% ) and unspecified abortion ( o06 , from 37.1% to 29.5% ) to abortion - related maternal deaths .
if the assumptions made by schiavon et al22 were correct , then an increase in maternal deaths associated with codes o06 and o05 would be expected , since illegal induced abortion contributes partially to unspecified abortion ( o06 ) and to other abortion ( o05 ) deaths in mexico . however , in contrast to the assumptions made by schiavon et al,22 the 22.9% decrease in mortality due to unspecified abortion ( o06 ) combined with other abortion ( o05 ) suggests that illegal abortions have decreased during the last decade in mexico .
it is important to note that code o05 is frequently used to classify maternal deaths due to complications of abortions caused by accidental injuries or violence - related trauma .
interestingly , most mexican states ( 30 out of 32 federal counties ) exhibit a specific non - punishable law for women in cases of an abortion provoked by unintentional injury , or intentional harm with the participation of a third part.32 national surveys on violence against women conducted in mexico in 2003 and 2006 show increases in the prevalence of violent relationships ( from 25.8% to 33.3% ) , physical violence from the current intimate partner ( from 9.8% to 33.3% ) , and physical violence during pregnancy ( from 5.3% to 9.4%).33,34 thus , the observed 3.1% to 7.7% increase in the relative contribution of maternal deaths due to other abortion ( o05 ) between 2002 and 2008 might be partially explained by an increase in violence towards women rather than an increase in illegal abortion .
although a more in - depth analysis is required to evaluate this postulate , if correct , mortality by illegal abortion would be even lower than current figures .
consequently , the apparent lack of progress in terms of maternal mortality due to abortion is not likely to be a reflection of an increase on complications from illegal abortions but rather explained by the emergence of a residual pattern of abortion - related deaths due to spontaneous abortions and other abortions .
this conjecture is strongly supported by the increase in the absolute number and relative importance of these causes over total abortion deaths ( table 4 and figure 5 , respectively ) , independently of the downward trend in overall mmr observed in mexico .
it seems that a common irregularity in specialized reports of maternal health is the lack of consensus when constructing or utilizing an indicator of study . in a previous study , homologation of icd codes related to deaths during pregnancy , childbirth , and puerperium
has been proposed for 7th through 10th versions.6 access to uniformity in icd codes of maternal death enables the scientific community to analyze and present results that are comparable among different regions . in the present study
, we propose a re - definition of some indicators regarding maternal health in table 5 , indicating differences when compared to mmr .
these are mmr with abortive outcome ( mmrao ) , amr , and induced amr ( iamr ) .
we propose these definitions to allow accurate and unequivocal use of these indicators when assessing advances in maternal health on both general and specific grounds , depending on the subject and territory in discussion .
since they are based on existing vital statistics , reliability will be directly proportional to that of the national mortality registry of the country evaluated . remarkably , these simple indicators are based on readily available figures of deaths by specific causes and registry of live births , allowing assessment of the progress of maternal health independently of the legal status of abortion of the territory under study .
the indicators proposed in table 5 may allow better interpretation of previously published reports , as well as orientation on forthcoming ones .
however , it is necessary to remark that these indicators do not resolve per se the problem of ambiguity and mixed interpretation of codes o05 and o06 of the current version of the icd .
when evaluating maternal health in latin american countries , epidemiological trends in maternal mortality observed in most of them show significant progress over the last three decades.2,3,6,20 clearly , decreasing abortion - related mortality is always a relevant factor that positively influences maternal health in a country .
nevertheless , it is also critically relevant to carefully analyze methodologies employed to estimate abortion figures and abortion - related mortality in countries where abortion is restricted or banned , as in most latin american countries , in order to provide reliable data for evidence - based public health interventions .
the reevaluation of methodologies used recently to estimate abortion figures and abortion - related mortality in mexico allows us to make the following important observations : considering the time elapsed since abortion legalization in mexico df ( ie , 5 years ) , it is expected that most of the previous illegally induced abortions have been replaced by legal procedures in this state .
even though some degree of underreporting in the number of elective abortions may occur in mexico df at the present , particularly in the private sector , the methodology used to estimate induced abortion figures11,12 has resulted in a significant overestimation ( at least 10-fold ) of induced abortion in this state .
the abortion registry in mexico df suggests that abortion legalization is associated with an increase in the number of legally induced abortions .
this is not surprising and has been well documented in developed countries.19,35 for example , induced abortion figures in spain have steadily increased between 1987 ( 2 years after its legalization ) and 2008 , from 16,728 to 115,812.16,36,37 reliable estimation of abortion - related mortality requires consideration of deaths by other abortion ( o05 ) , unspecified abortion ( o06 ) , and failed attempted abortion ( o07 ) as the most likely indicators of deaths suspected to be related to complications of illegal abortion in latin american developing countries . clearly , it is misleading to include other well - defined causes with an abortive outcome ( eg , ectopic pregnancy , spontaneous abortion , and other specific pathological conditions ) in this context because these outcomes are not related to induced abortion .
since the mexican mortality ratio by other abortion ( o05 ) and unspecified abortion ( o06 ) has decreased by 22.9% between 2002 and 2008 ( 1.44 to 1.10 deaths per 100,000 live births ) , along with a more discrete reduction of the relative contribution of these categories to all causes of death with an abortive outcome ( from 40% to 37% ) during the same period , it is possible to suggest that illegal abortion and/or complications related to illegal abortions have decreased in mexico .
overall , all deaths with an abortive outcome ( o00o08 ) in mexico represent 6.5% of global maternal causes of death .
interestingly , specific pathological conditions ( o00o02 ) and spontaneous abortions ( o03 ) appear to be the major components of maternal mortality due to abortion in mexico , with a relative contribution of over 60% to global abortion - related mortality during 2008 .
if the number of illegal induced abortions for mexico is between 725,070 and 1,024,424,11 then a high morbidity and mortality by other abortion ( o05 ) , unspecified abortion ( o06 ) , and failed attempted abortion ( o07 ) would be expected . however , the contribution of these categories to overall maternal mortality in mexico is barely 2% to 4% of the total causes of maternal death .
for instance , according to official figures for the whole country in 2009 , the iamr was 0.97 per 100,000 live births .
indeed , other abortion ( o05 ) and unspecified abortion ( o06 ) represented barely 2.07% of the total causes of maternal death ( 25 cases out of 1207 total maternal deaths ) .
the increase in the absolute number and relative importance of other abortion ( o05 ) between 2002 and 2008 might be partially explained by an increase in violence towards women or unintentional injuries rather than an increase in illegal abortion .
re - defining indicators of abortion mortality ( see table 5 ) becomes useful when assessing whether each indicator reflects complications of general abortive outcome , and if they are the result of spontaneous or induced procedures .
this may prove crucial when assessing the influence of induced or illegal abortion on maternal health in latin america .
taken together , these observations indicate that the maternal health of mexico may be slightly improved by policies directed to addressing abortion - related complications , increasing coverage in obstetric emergency facilities , and specialized obstetric care.6 more importantly , this approach will additionally have a positive impact by decreasing overall maternal causes of death .
it is necessary to emphasize that approximately 98% of maternal deaths are related to causes other than illegal induced abortion in mexico .
therefore , only marginal or practically null effects would be expected from abortion legalization or abortion prohibition on overall maternal mortality rates in this latin american country , as recently shown in a natural experiment conducted in chile.6 finally , considering the current profile of mexican maternal mortality , it can be hypothesized that maternal health in this country would greatly benefit from public health policies directed to provide adequate medical treatment of conditions such as hemorrhage , gestational hypertension , eclampsia , and indirect causes of maternal death , mainly characterized by pre - existing chronic diseases . | ### Summary:
: in countries where induced abortion is legally restricted , as in most of latin america , evaluation of statistics related to induced abortions and abortion - related mortality is challenging .
the present article reexamines recent reports estimating the number of induced abortions and abortion - related mortality in mexico , with special reference to the international classification of diseases ( icd ) .
we found significant overestimations of abortion figures in the federal district of mexico ( up to 10-fold ) , where elective abortion has been legal since 2007 .
significant overestimation of maternal and abortion - related mortality during the last 20 years in the entire mexican country ( up to 35% ) was also found .
such overestimations are most likely due to the use of incomplete in - hospital records as well as subjective opinion surveys regarding induced abortion figures , and due to the consideration of causes of death that are unrelated to induced abortion , including flawed denominators of live births .
contrary to previous publications , we found important progress in maternal health , reflected by the decrease in overall maternal mortality ( 30.6% ) from 1990 to 2010 .
the use of specific icd codes revealed that the mortality ratio associated with induced abortion decreased 22.9% between 2002 and 2008 ( from 1.48 to 1.14 deaths per 100,000 live births ) .
currently , approximately 98% of maternal deaths in mexico are related to causes other than induced abortion , such as hemorrhage , hypertension and eclampsia , indirect causes , and other pathological conditions .
therefore , only marginal or null effects would be expected from changes in the legal status of abortion on overall maternal mortality rates .
rather , maternal health in mexico would greatly benefit from increasing access to emergency and specialized obstetric care .
finally , more reliable methodologies to assess abortion - related deaths are clearly required . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: a duplication cyst is a spherical or tube - shaped structure covered with luminal epithelial cells , which is attached to a portion of the gastrointestinal tract .
although it is a rare congenital anomaly , it can occur anywhere in the digestive tract .
it has been reported to be particularly common in the small intestine , followed by the terminal ileum , the jejunum , and the duodenum , in that order.1 - 3 the incidence in the duodenum is approximately 4% to 12% or approximately one in 100,000 individuals , preferentially in the bulb and the second portion of the duodenum.4 - 6 in most cases , it occurs during infancy , and is asymptomatic until its detection , although it is sometimes detected in adults .
the time of manifestation of symptoms is diverse , from infancy to childhood or adulthood .
the clinical features are duodenal obstruction , obstructive jaundice , and hemorrhage ; and pancreatitis may develop in rare cases.6,7 in many cases , diagnosis and treatment via cyst removal are performed simultaneously .
the authors report here a case of incidental detection of a duodenal duplication cyst manifested by a duodenal polyp .
a 62-year - old female visited our hospital due to a polypoid lesion in the duodenum on the health check - up endoscopy .
the patient 's history of diabetes , hypertension , and surgery was not surfaced earlier , and there were no special findings from her and her family 's social history . on physical examination at admission , vital signs were stable and other tests were normal .
peripheral blood test showed white blood cell 6,080/mm , hemoglobin 9.9 g / dl , hematocrit 29.9% , and platelets 223,000/mm . on biochemical analysis ,
the blood urea nitrogen was 23.5 mg / dl , creatinine 0.6 mg / dl , amylase 94 u / l , lipase 39 u / l , total protein 6.4 g / dl , albumin 3.8 g / dl , total bilirubin 0.34 mg / dl , direct bilirubin , 0.08 mg / dl , ast / alt 19/22 u / l , and alkaline phosphatase 173 iu / l .
on endoscopy , about 1-cm sized , y - iii polypoid lesion was seen at the posterior wall of the superior duodenal angle , which was soft and easily movable by pressing with a biopsy forceps ( fig .
endoscopic ultrasound ( eus ) showed that the lesion was an anechoic cystic lesion located in the third layer , and that the cyst wall consisted of three layers ( fig .
for the diagnosis and treatment , endoscopic mucosal resection ( emr ) was performed ( fig .
the cyst wall was contiguous with the duodenum and surrounded by smooth muscle layer , inner and outer surfaces of which were formed by the normal duodenal mucosa ( fig .
, the lesion has not recurred , and the patient is still under follow - up observation .
gross et al.8 defined a gastrointestinal duplication cyst in 1952 as satisfying the following three criteria : first , the cyst should be closely attached to the corresponding organ ; second , the inside and outside of the cyst should be covered with the intestinal mucosa ; and third , the cyst should have a smooth muscle layer .
histologically , duplication cysts refer to cysts that are filled with fluid and formed by well - developed smooth muscle layers and the mucosal layer , which is made up of tissues identical to the host gastrointestinal tract .
occasionally , the cysts may contain gastric or duodenal epithelial cells , or pancreatic or respiratory epithelial cells . although the duplication cyst is a rare congenital anomaly , it may occur anywhere along the digestive track .
its incidence in males is identical to its incidence in females.2,3 most duodenal duplication cysts are filled with clear mucosal secretion , and range from 1 to 25 cm in size , depending on the volume of their secreted materials .
duodenal duplication cysts occur primarily along the anterior wall.9 the clinical features of duodenal duplication cysts range from non - specific symptoms such as vomiting , anorexia , abdominal pain , and abdominal distention , to small bowel obstruction due to the filling of the cyst with secretion . in addition ,
duodenal bleeding caused by ulceration , peritonitis , pancreatitis , jaundice , intussusception , and infection has been reported.10 - 12 diseases that should be differentiated from duodenal duplication cysts are all diseases that may appear as duodenal ulcer on the upper gastrointestinal series , such as lipoma , tumors in the ampulla of vater , carcinoids , pancreatic pseudocysts , and choledochal cysts.6 duodenal duplication cysts are occasionally detected with recurrent pancreatitis or idiopathic gastrointestinal hemorrhage .
nonetheless , few cases of asymptomatic duodenal duplication cysts , as in this case , which were incidentally detected as polypoid lesions , have been reported .
duodenal polypoid lesions are diverse ; endoscopic biopsy and eus are sometimes performed for more information in some lesions , but accurate diagnosis is ultimately confirmed by resection .
we decided to resect the lesion because of the patient 's request and in order to confirm the diagnosis .
although " watchful waiting " is the typically recommended strategy for benign cystic lesion in small intestine , this approach imposes a tremendous emotional burden on patients , who can become preoccupied with thoughts that the lesion might be malignant or that complications such as bleeding or obstructions will develop .
recently , health check - up endoscopy is very popular and so it is deemed that more cases of asymptomatic duodenal duplication cysts will be reported .
it may be diagnosed incidentally or with abdominal pain , pancreatitis , or hemorrhage symptoms - in other words , due to associated complications .
recently , with the increase in the number of endoscopic examinations , numerous lesions are being detected incidentally . in this paper , a case of a duodenal duplication cyst which was detected as an asymptomatic polypoid lesion in an adult is reported with a literature review . | ### Summary:
: duodenal duplication cyst is a rare anomaly , totaling only 4% to 12% of gastrointestinal duplications , and is usually encountered during infancy or in early childhood .
most are commonly located posterior to the first or second portion of the duodenum .
presenting signs and symptoms include vomiting , decreased oral intake , periumbilical tenderness , abdominal distention , obstructive jaundice , acute pancreatitis , and gastrointestinal bleeding .
the traditional treatment of a duodenal duplication cyst has been complete surgical resection , but very few cases of endoscopic treatment have been reported in the literature . here , we report a case of duodenal duplication cyst that was manifested by a duodenal polyp . |
<s> [INST] <<SYS>> You a helpful assistant capable of providing accurate and concise responses. You will assist me in generating Summary.<</SYS>> [/INST] <s> ### Text:
: summer 2009 , adult individuals of culex pipiens were caught by using different models of co2 and light traps in rural habitats at 10 different european locations ( fig .
mosquitoes were preserved in 90% ethanol and sent to uppsala by mail by the local mosquito researchers .
pipiens population was represented by 30 adult individuals , all from wild , over - ground populations .
dna from individual mosquitoes was extracted by a chelex procedure proteinase - k - based extraction ( 16 ) using the protocol provided by the manufacturer .
pipiens
( 4 , 1719 ) ( cq13 , cq29 , cxpgt9 , cxpgt20 , cxpgt40 , cxpgt46 , cxpgt51 , and cxpgt53 ) and followed the pcr - protocols given in the original paper .
we used the software microchecker ( 20 ) to check for null alleles and other technical problems .
we detected a significant number of null alleles in several loci , apparent as an uncommonly large proportion of homozygotes for a few alleles , which created large deviations from hardy weinberg equilibrium .
the repeatability of the amplifications was 95% ; so , there are no reasons to believe that technical problems caused this pattern .
since several samples did not amplify at all for a given locus , there are reasons to suspect that there are alleles present that did not amplify .
null alleles are commonly found in lepidoptera ( 21 ) and seem to be present also in this dipterian sample .
the main effect of null alleles seems to be an overestimate of f
st
( 22 ) , but no major distortions of genetic structure .
we used the method by chapuis and estoup ( 23 ) to correct for the presence for null alleles since this method performed best in a comparative study .
the method is implemented in the software freena ( 23 ) . to perform basic statistics , such as
the number of alleles , allelic richness , and expected heterozygosity , we used the softwares arlequin 3.5.1.2 ( 24 ) and fstat 2.9.3.2 ( 25 ) . to calculate pairwise
f
st , we used freena using both uncorrected data and data corrected for null alleles ; 95% confidence intervals were obtained through 1000 bootstrap replicates . since f
st is dependent on the level of heterozygosity , a low estimate can be due to a high within population variation rather than lack of differentiation .
we therefore also calculated gst
( 26 ) , which rescales f
st to have bounds between zero and one to get an intuitive picture of the degree of differentiation . to tests for possible isolation by distance patterns
, we used the program mantel 2.0 ( 27 ) . finally , to make neighbor - joining ( nj ) trees based on the distances obtained , we used mega5 ( 28 ) . to assess
if the sampling and the number of loci used was enough to detect a structure if there is one ( i.e. power of the tests ) , we used the program powsim ( 29 ) .
we used all loci and simulated f
st - values for two populations being separated for 250 generations , each with an effective population size ( n
e ) of 5000 and with a sampling effort of 30 individuals ( as in this study ) .
the values were used to simulate a case where the split of the populations are very recent , and the populations are very large .
hence , this is a very conservative test of power , as if time is longer and n
e is smaller , it would be much easier to find significant results .
nevertheless , even with these very conservative start values , we found that the expected f
st is 0.025 ( 95% range , 0.01390.0392 ) and the power 0.99 .
thus , we are confident that , given the number of loci and sampling effort , we can find differences if they exist .
consequently , we were not able to estimate genetic differentiation , as our data adjustments can not cope with functions such as , for example , the estimation of gene flow . when the data are adjusted for null alleles ( alleles that do not amplify ) , multilocus estimates of gene flow
instead we used so - called private alleles ( i.e. alleles only found in one population ; 30 ) assuming that there were a number of private alleles that did not amplify ( null alleles ) .
with help of genepop and by using private alleles , we estimated the number of migrants per generation across all populations .
the aim of estimating the gene flow with this method was to test if the observed amount of divergence was affected by gene flow or if it was what we could expect when no gene flow has occurred since separation . to implement this
, we calculated expected f
st by simulations using powsim with n
e values ranging from 100 to 10,000 and time since separation ( t ) ranging from 100 to 5000 generations and allele frequencies taken from the observed data .
this will give us a range of expected f
st - values for different combinations of n
e and t ( for results , see fig .
4 ) . populations from romania , turkey , and france were excluded from this calculation since they probably belong to another group of culex . to estimate n
e , we used the method of xu and fu 2004 ( 31 ) designed for highly variable markers such as microsatellites , where = 4 n
e , and is the mutation rate . if the parameter values needed to get the observed f
st - values are outside what is realistic in this system , we can reject the hypothesis of no gene flow between them .
summer 2009 , adult individuals of culex pipiens were caught by using different models of co2 and light traps in rural habitats at 10 different european locations ( fig .
mosquitoes were preserved in 90% ethanol and sent to uppsala by mail by the local mosquito researchers .
pipiens population was represented by 30 adult individuals , all from wild , over - ground populations .
dna from individual mosquitoes was extracted by a chelex procedure proteinase - k - based extraction ( 16 ) using the protocol provided by the manufacturer .
pipiens
( 4 , 1719 ) ( cq13 , cq29 , cxpgt9 , cxpgt20 , cxpgt40 , cxpgt46 , cxpgt51 , and cxpgt53 ) and followed the pcr - protocols given in the original paper .
we used the software microchecker ( 20 ) to check for null alleles and other technical problems .
we detected a significant number of null alleles in several loci , apparent as an uncommonly large proportion of homozygotes for a few alleles , which created large deviations from hardy weinberg equilibrium .
the repeatability of the amplifications was 95% ; so , there are no reasons to believe that technical problems caused this pattern .
since several samples did not amplify at all for a given locus , there are reasons to suspect that there are alleles present that did not amplify .
null alleles are commonly found in lepidoptera ( 21 ) and seem to be present also in this dipterian sample .
the main effect of null alleles seems to be an overestimate of f
st
( 22 ) , but no major distortions of genetic structure .
we used the method by chapuis and estoup ( 23 ) to correct for the presence for null alleles since this method performed best in a comparative study .
the method is implemented in the software freena ( 23 ) . to perform basic statistics , such as
the number of alleles , allelic richness , and expected heterozygosity , we used the softwares arlequin 3.5.1.2 ( 24 ) and fstat 2.9.3.2 ( 25 ) . to calculate pairwise
f
st , we used freena using both uncorrected data and data corrected for null alleles ; 95% confidence intervals were obtained through 1000 bootstrap replicates .
since f
st is dependent on the level of heterozygosity , a low estimate can be due to a high within population variation rather than lack of differentiation .
we therefore also calculated gst
( 26 ) , which rescales f
st to have bounds between zero and one to get an intuitive picture of the degree of differentiation . to tests for possible isolation by distance patterns
, we used the program mantel 2.0 ( 27 ) . finally , to make neighbor - joining ( nj ) trees based on the distances
obtained , we used mega5 ( 28 ) . to assess if the sampling and the number of loci used was enough to detect a structure if there is one ( i.e. power of the tests ) , we used the program powsim ( 29 ) .
we used all loci and simulated f
st - values for two populations being separated for 250 generations , each with an effective population size ( n
e ) of 5000 and with a sampling effort of 30 individuals ( as in this study ) . the values were used to simulate a case where the split of the populations are very recent , and the populations are very large .
hence , this is a very conservative test of power , as if time is longer and n
e is smaller , it would be much easier to find significant results .
nevertheless , even with these very conservative start values , we found that the expected f
st is 0.025 ( 95% range , 0.01390.0392 ) and the power 0.99 .
thus , we are confident that , given the number of loci and sampling effort , we can find differences if they exist .
consequently , we were not able to estimate genetic differentiation , as our data adjustments can not cope with functions such as , for example , the estimation of gene flow . when the data are adjusted for null alleles ( alleles that do not amplify ) , multilocus estimates of gene flow
instead we used so - called private alleles ( i.e. alleles only found in one population ; 30 ) assuming that there were a number of private alleles that did not amplify ( null alleles ) .
with help of genepop and by using private alleles , we estimated the number of migrants per generation across all populations .
the aim of estimating the gene flow with this method was to test if the observed amount of divergence was affected by gene flow or if it was what we could expect when no gene flow has occurred since separation . to implement this
, we calculated expected f
st by simulations using powsim with n
e values ranging from 100 to 10,000 and time since separation ( t ) ranging from 100 to 5000 generations and allele frequencies taken from the observed data .
this will give us a range of expected f
st - values for different combinations of n
e and t ( for results , see fig .
populations from romania , turkey , and france were excluded from this calculation since they probably belong to another group of culex . to estimate n
e , we used the method of xu and fu 2004 ( 31 ) designed for highly variable markers such as microsatellites , where = 4 n
e , and is the mutation rate . if the parameter values needed to get the observed f
st - values are outside what is realistic in this system , we can reject the hypothesis of no gene flow between them .
the number of alleles , allelic richness , and expected heterozygosity did not differ much between the populations ( table 1 ) .
the global f
st was 0.090 ( 95% ci : 0.0490.14 ) using the uncorrected data set and 0.054 ( 95% ci : 0.0320.80 ) .
the pairwise f
st - values were low but were not different from zero , except in one case ; between denmark and serbia ( table 2 ) .
however , the comparisons that involved the samples from france , rumania , and turkey were highly differentiated from the rest of the populations .
2 , the distance between populations was on average lower using the corrected data set .
if we exclude the three deviating populations , global f
st was now only 0.029 ( 0.0180.041 ) and 0.022 ( 0.0150.028 ) , respectively , which corresponds to gst - values of 0.20 and 0.15 , respectively .
the two estimates of f
st was strongly correlated ( r=0.99 , p<0.001 ; mantel test ) .
there was a significant correlation between geographic and genetic distances [ log ( distance ) versus f
st/(1 f
st ) , r=0.31 , p=0.0.032 for the corrected data set , mantel test ] .
neighbor - joining ( nj ) trees illustrating the genetic distance between populations ( a ) without correction for null alleles , ( b ) with correction , ( c ) using the lower 2.5 interval , and ( d ) using the upper 2.5 interval .
number of individuals sampled , number of alleles ( se ) , allelic richness , ar ( se ) , and expected heterozygosity ( se ) for the different populations pairwise distances with ( a ) uncorrected f
st and ( b ) corrected values two of the markers used here were the same that were used in fonseca et al .
( 4 ) , where two distinct lineages were found . in one of the loci cxpgt9 ,
the allele frequency spectrum of the three outlying populations ( france , romania , and turkey ) was similar to the underground populations discovered in ref .
( 4 ) and the allele frequency spectrum for the rest was close to the one found in the above - ground populations found in ref .
3a , where the allele size 116 [ corresponding to allele size 114 in ref .
( 4 ) ] is shown to be very frequent in france , romania , and turkey . in ref .
( 4 ) , the same allele reached a frequency of around 0.5 , while in the other populations , the frequencies were much lower .
allele size 124 , on the other hand , was not found in romania , turkey , or france , but in all other populations , at about the same frequency .
it is also worth noting that allele size 116 , being the most frequent one in the putative underground populations , was found in almost all of the other populations , albeit at a much lower frequency .
this suggests a gene flow between the underground populations and the above - ground populations .
the same pattern can be seen in locus cq29 where allele size 178 reaches a high frequency in the above - ground populations , but not in the below - ground populations ( fig .
3b ) , while allele size 184 is very common in france , being almost the only allele found , and relatively common in romania , but having a low frequency in turkey .
both alleles are found in both groups , but at a much lower frequency , again indicating some gene flow between the groups .
frequencies of two alleles in ( a ) locus cxpgt9 and ( b ) qt29 in the different populations .
the mean frequency of private alleles was 0.026 , which when corrected for sample size yields an estimate of the number of migrants of 5.74 .
the number of migrants between malta and sweden ( the most distant populations ) was as high as 2.04.we found that the estimate of effective population , = 2.85 , which assuming a mutation rate for microsatellites ( ) of 510 , gives an estimate of n
e1500 , and with a more conservative estimate of 10 , gives n
e7100 . to obtain the range of observed f
st - values by drift alone
, we would expect n
e in the range of at least 6000 , which is possible given the conservative estimate of mutation , but only at short times since separation ( fig .
even if the observed f
st - values are not unattainable , the conditions under which this might happen are quite restricted . expected f
st values ( shaded areas ) in relation to time to separation in generations ( x - axis ) and effective population size ( n
e ) based on simulations in powsim .
the line indicates the upper limit of f
st - levels observed in the current study , and thus the observed values are only possible under a model of pure genetic drift for parameter values above the line .
the dotted line indicates the average of the estimated n
e over all populations .
the study showed two major results : first , three of the analyzed populations ( france , romania , and turkey ) were very different from the rest of the populations ( sweden , denmark , alsace , croatia , serbia , spain , and malta ) and they also greatly differed from each other ( table 2 , fig .
2 ) . in fact , they were so different that there are reasons to believe that they belong to differentiated lineages
. furthermore , the allele frequency distribution in these populations match the one that has been earlier found in the underground populations ( 4 ) .
second , most pairwise differences were low and showed a shallow structure among the populations apart from the three deviating ones ( fig .
the low f
st - values between populations suggest that there is an extensive gene flow between the populations , and this was confirmed by the simulations where the conditions for differentiation by drift alone was far too stringent given what is known about these populations .
a low f
st by itself does not mean that there is extensive gene flow ( 32 ) since f
st is dependent on the level of heterozygosity .
however , even if we rescale the values to account for within - population heterozygosity , the overall level of differentiation is still low in the above - ground populations .
thus , we are confident that basically all european populations of the above - ground cx .
the estimate of gene flow was high , which together with the simulations , suggests that the genetic similarity among populations is due to ongoing gene flow rather than a result of a recent shared history and expansion .
an alternative explanation is that the species only very recently spread throughout europe , and thus due to incomplete lineage sorting and subsequent local stochastic effects , the populations have not diverged more , which is reflected in the unclear relationships between the populations .
however , this species were described by linnaeus in 1758 ( 33 ) , and there are no reasons to believe that it was an uncommon species at that time .
even if the species had very recently arrived to northern europe when linnaeus described it , 250 years is ample time to develop a population structure if gene flow is restricted or absent .
the results from the power analysis confirm this ; the expected f
st - values are in our simulation higher than observed here , even though we used very conservative input - values .
this strengthens the support for a wide - ranging dispersal of mosquito - individuals across large distances in europe , and hence the possibility of a spread of vector - borne pathogens .
vector competence of mosquitoes describes their ability to transmit pathogens after taking an infected blood meal .
the ability of vectors transmitting a pathogen is known to vary between populations of mosquito species .
the exact relationship between vector competence and environmental factors is however not clear and can be influenced by many external factors ( 8) . according to our study
, an extensive amount of gene exchange , and hence exchange of individuals , occurs between populations of cx .
, infectious diseases spread by this species may not be associated with a certain vector genotype , but rather with suitable environmental conditions .
the distribution and intensity of mosquito - borne infections is strongly influenced by the interactions between temperature , vectors , hosts , and pathogen genetics .
temperature often determines both the latitudinal boundary and upper elevation limit of pathogen transmission when the extrinsic incubation period becomes greater than the life span of the vector ( 8) .
temperature is also linked to the intensity and transmission of pathogens . in temperate regions ,
seasonality is one of the key components of the climate . in many temperate regions , however
therefore , tropical mosquito - borne diseases can be introduced and transmitted during the right season in the temperate regions , but in most cases , they will be eliminated during the winter ( 1 ) . some viruses , however , such as the usutu virus in austria , have been shown to be able to maintain in a natural cycle with a minimum of at least 10 days / year with a temperature > 30c ( 10 ) . it is also predicted that usutu virus will become endemic in large parts of central europe before the end of the century and that optimal environmental conditions for outbreaks of this virus will occur in about 10 years from now ( 10 , 34 ) .
pipiens and molestus . because pipiens is strictly ornithophilic while molestus has a more catholic taste and readily bites humans and other mammals , these hybrid populations are thought to be the most high - capacity vectors in southern europe and north america ( 35 ) .
this gives rise to concern , should those hybrids spread to northern europe or if another hybridization event should occur .
pipiens in sweden and the rest of northern europe are less likely to be involved in zoonotic transmission of , for example , wnf since they are not constituted of hybrids . however , in a recent paper , reusken et al .
( 35 ) showed the presence of hybrid pipiensmolestus mosquitoes in the netherlands . since our results imply an extensive gene flow between populations of cx .
this could potentially alter the epidemiology of many arthropod - borne viruses in northern europe giving rise to epidemics / epizootics similar to the wnf outbreak in north america from 1999 and onward .
consequently , up - to - date surveillance systems are called for all over the europe as , without them , detection and response to emerging vector - borne diseases can be severely impaired ( 36 ) .
the emergence of wnf in 1999 in new york is a good example of the consequences that a delayed response can have on the outcome of novel pathogen introduction .
studies show that impaired mosquito surveillance can make the management costs of epidemics several times higher than applying a strategy with sustained surveillance and early case detection ( 36 ) .
the authors have not received any funding or benefits from industry or elsewhere to conduct this study . | ### Summary:
: backgroundspecies in the culex pipiens complex are common almost all over the world and represent important vectors for many serious zoonotic diseases . even if , at the moment , many of the pathogens potentially transmitted by cx .
pipiens are not a problem in northern europe , they may , with increasing temperatures and changing ecosystems caused by climate change , move northward in the future .
therefore , the question whether or not the cx .
pipiens populations in northern europe will be competent vectors for them is of high importance .
one way to estimate the similarity and the rate of contact between european cx .
pipiens populations is to look at the gene exchange between these populations.methodsto test the genetic diversity and degree of differentiation between european cx .
pipiens populations , we used eight microsatellite markers in 10 mosquito populations originating from northern , central , and southern europe.resultswe found that three of the analyzed populations were very different from the rest of the populations and they also greatly differed from each other . when these three populations were removed , the variance among the rest of the populations was low , suggesting an extensive historic gene flow between many european cx .
pipiens populations.conclusionsthis suggests that infectious diseases spread by this species may not be associated with a certain vector genotype but rather with suitable environmental conditions .
consequently , we would expect these pathogens to disperse northward with favorable climatic parameters . |
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: a 19-year - old female presented with recurrent hemoptysis and oral ulceration . her first experience of hemoptysis had been 2 years earlier ; she was admitted to a local hospital at that time .
bronchofiberscopy revealed diffuse alveolar hemorrhage ; however , there were no specific findings for the cause of hemoptysis .
the patient was diagnosed with behcet 's disease ( bd ) since she had oral ulcers and erythematous skin lesions .
two years later , she presented with hemoptysis and went through an additional bronchofiberscopic exam .
the exam revealed a hyperemic nodular lesion within the anterior basal segmental bronchus of the right lower lobe ( rll ) .
the patient was discharged with the same medication after conservative treatment . however , the patient experienced another episode of hemoptysis and was referred to seoul asan medical center emergency room . a rheumatologist and an ophthalmologist
were consulted for a differential diagnosis between bd and hughes - stovin syndrome ( hss ) .
further , since these two conditions have a strong predilection for the male gender , a gynecologist examined the patient for thoracic endometriosis .
the patient 's physical examination showed oral ulcers but no evidence of genital ulcers , uveitis , and skin lesions . according to her past history
, she had had no skin lesions since 2 years earlier , and hemoptysis occurred without any association with her menstrual cycle .
chest computed tomography showed residual ground - glass opacity in rll due to aspirated blood , but no definite endobronchial lesion or vascular abnormality were observed as the cause of hemoptysis .
the patient 's blood test was normal except for a mild elevation of the erythrocyte sedimentation rate ( 29 mm / hr ) .
for the differential diagnosis , anti - nuclear antibody , rheumatoid factor , serum complement levels ( c3 and c4 ) , and anti - neutrophil cytoplasmic antibodies ( c - anca and p - anca ) were tested ; all of them showed negative results .
a small polyp was observed at the anterior basal segmental bronchus of the rll and excisional biopsy was proceeded ( fig .
after transection of the basal segmental bronchus , intraoperative bronchoscopy showed no bleeding focus in the endobronchial area .
chest tube drainage was removed on postoperative day 3 , and the patient was discharged the next day with 5 mg / day of oral prednisolone .
pathological examination revealed abnormally dilated vascular structures in the bronchial submucosa with rupture ( fig .
2 ) . considering pulmonary aneurysm , an oral ulcer with no evidence of systemic thrombosis
pulmonary involvement of bd and hss is characterized by thrombophlebitis and pulmonary aneurysm . to distinguish hss from bd , physical examination and close observation are important .
specific features to bd are known to be oral ulcers , recurrent genital ulceration , eye lesions , skin lesions , and a positive pathergy test . however , thus far , the diagnostic criteria for hss have not been formally established as the etiology of hss is still unclear and only a few cases of the disease have been reported .
therefore , hss is diagnosed if a patient presents with a combination of aneurysm and thrombosis without any specific features of bd
. however , other clinical features are not specific since thrombophlebitis and aneurysm can occur anywhere , including in the hepatic artery , iliac artery , vena cava , cardiac chambers , femoral vein , iliac vein , and dural sinuses .
the patients may present cough , dyspnea , pulmonary hypertension , intracranial hypertension , fever , chills , chest pain , and hemoptysis .
the blood tests can show leukocytosis , elevated c - reactive protein , erythrocyte sedimentation rate , and anemia when hemoptysis or aneurysmal rupture occurs .
radiologic evaluations , including chest x - ray and chest computed tomography , could be useful only in few patients with large aneurysms .
when the patient has thrombosis in the vena cava and has a high risk of aneurysmal rupture , angiography should not be performed .
bronchoscopy might be useful in patients who present hemoptysis with bronchial artery aneurysm , and a doppler ultrasound of extremities is important for evaluating the presence of deep venous thrombosis .
some patients , however , do not meet the international classification criteria for bd , as in this case .
they may be indistinguishable from patients with hss since the radiological and histopathological findings are similar .
further , the final clinical stage in both conditions is aneurysmal rupture with massive hemoptysis , which leads to a high mortality rate .
therefore , hss is suggested as an atypical manifestation of bd . considering the histopathological findings , the medical management is similar in both diseases : steroids alone or in combination with immunosuppressants .
however , a standard treatment of hss has not been established because of its unknown etiology .
lobectomy or pneumonectomy could be performed to remove the aneurysm . however , in cases of extensive bilateral multiple aneurysms , operative treatments might be associated with high mortality and morbidity rates . for
both diseases , however , are associated with high mortality because of the massive hemoptysis in the final stage .
therefore , early diagnosis and immediate surgical resection are crucial for prevention of disastrous complication and mortality .
further , as in this case , the surgical team should be well prepared since an invasive evaluation might cause unexpected complications when the patient is suspicious of pulmonary or bronchial artery aneurysm . | ### Summary:
: pulmonary and/or bronchial aneurysm with systemic thrombophlebitis can be seen in the case of both behcet 's disease and hughes - stovin syndrome .
these two diseases may be indistinguishable since the clinical , radiological , and histopathological findings are similar in both cases .
in particular , from the perspective of pulmonary involvement , hemoptysis is the leading cause of death in both conditions and is followed by aneurysmal rupture . here
, we report a case in which surgical resection was performed for a patient presenting recurrent hemoptysis as an atypical presentation of behcet 's disease . |