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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:
: the cancer cells are capable of avoiding apoptosis , a programmed suicide mechanism , which confers them the ability of limitless cell expansion.1 cancer is the leading cause of mortality worldwide ; it was accountable for 8.2 million deaths in 2012 according to the world health organization statistics , and its incidence is expected to increase to 13.0 million by 2030 .
unfortunately , due to the lack of selectivity for cancerous cells , no optimal chemotherapeutic agents have been identified to date .
researchers are therefore centralizing their efforts on discovering valid targets and designing new therapeutic inhibitors.25 glyoxalase system enzymes have been approved as valid targets for cancer treatment.68 these enzymes present an attractive target for cancer therapy owing to their overexpression in malignant cells and involvement in increasing resistance to antitumor agents .
the glyoxalase system comprising two enzymes , glyoxalase-1 ( glo - i ) and glyoxalase-2 ( glo - ii ) , is responsible for the detoxification of metabolic byproducts produced by cells , particularly reactive aldehydes , such as methylglyoxal ( mg ) .
glo - i catalyzes the first step , which is isomerization of the toxic metabolite , and the detoxification process is subsequently accomplished via hydrolysis of the glo - i product , s - d - lactoylglutathione , to generate nontoxic bystanders that are safely excreted outside the body ( figure 1).913 tumor cells are metabolically more active than normal cells , resulting in increased cellular levels of toxic mg and s - d - lactoylglutathione metabolites .
tumor cells respond by augmenting the activity of the detoxifying glyoxalase system to minimize the intracellular concentrations of toxic metabolites .
this phenomenon has been reported in breast carcinoma by rulli et al14 and human superficial or invasive bladder cancer by mearini et al,15 who showed that activities of both glo - i and glo - ii are significantly increased in tumors , compared to those in normal cells .
this finding rationalizes that inhibition of the glyoxalase system ( glo - i and/or glo - ii ) may be detrimental for cancer cells , potentially leading to their self - destruction.14,1622 structurally , glo - i is a homodimeric enzyme composed of two identical polypeptide chains , each comprising 183 amino acids .
zinc is an essential cofactor present within the glo - i active site that plays an important structural and catalytic role in the isomerization of reactive and toxic aldehydes via stabilizing the enediolate intermediate by lowering the free activation energy of proton transfer.23 the glo - i active site is located at the interface of the two polypeptide chains , and the zinc atom displays octahedral coordination with adjacent amino acids from both chains.24,25 glo - i , an established pivotal anticancer target , has been the focus of research by several groups .
for example , more et al2632 designed a number of glo - i transition - state competitive inhibitors incorporating different zinc - binding groups ( zbgs ) .
takasawa et al3335 additionally identified natural flavonoids , such as glo - i inhibitors , and showed that coplanar hydroxyl and ketone groups are important for zinc chelation ( figure 2 ) .
previously , we performed active site analysis of glo - i to determine the pivotal features essential for optimal inhibitor binding with the active site.28 three features were determined as critical : a zinc - binding region in the inhibitor possessing a zbg to chelate the zn ion , the presence of a negatively ionizable group in the inhibitor for binding to the positively ionized active site mouth , and a deep hydrophobic pocket that could be filled with a hydrophobic group.28 in this study , we mined the commercially available aldrich database for extraction of potential inhibitors of glo - i by selecting a ketol group ( present in myricetin ) as the zbg and carboxylic acid to complement the positively ionized active site mouth .
final selection of potential inhibitors was achieved by performing flexible docking to estimate binding energy , along with establishing a good perception of the binding modes of these inhibitors within the active site .
the biological inhibitory activities of the selected hits against glo - i were evaluated via in vitro assay .
discovery studio ( ds ) 3.5 from biovia software inc http://www.3ds.com/products-services/biovia/ ( san diego , ca , usa ) was used for active site analysis , extraction of potential inhibitors from commercial databases ( aldrich ) , and flexible docking .
the crystal structure of glo - i ( accession code : 1qin ) was retrieved from the protein data bank ( pdb ) as our structural model.25 the crystal structure of glo - i , obtained from pdb , was prepared using the prepare protein protocol , in which missing loops and alternate conformations were corrected .
the active site was determined from the cocrystallized ligand bound within , along with the zinc atom .
the glo - i enzyme active site is mapped as three main areas : a highly positive active site mouth containing arginine and lysine , a hydrophobic pocket deep within the active site , and zinc atom coordinated between these two areas.28 the commercially available aldrich database ( containing 250,000 compounds ) from sigma - aldrich co. ( st louis , mo , usa ) was downloaded and converted into a three - dimensional database using the build 3d database protocol in ds .
the database was searched for potential inhibitors of glo - i based on the active site and the function of the ketol group , which can chelate zinc atom.34 the search query was based on two steps : extraction of all compounds containing a ketol group with the potential to chelate zinc atoms , followed by selection of carboxyl - containing compounds from hits retrieved from the first step which were expected to bind to the mouth of the active site .
these steps were performed using the ligand pharmacophore mapping protocol within ds , which aligns and identifies the ligands that map to a pharmacophore . moreover , with application of absorption , distribution , metabolism , excretion , and toxicity ( admet ) profiling and lipinski s and veber s rules , hits were reduced to obtain drug - like compounds and facilitate the process of flexible docking , which is computationally expensive .
final selection of the anticipated inhibitors was based on docking studies in parallel with visual inspection .
the protein active site was determined using the edit and define active site tool available in ds .
the active site was defined by a sphere of 11 radius encompassing the three main areas .
flexible docking protocol in ds 3.5 was used to facilitate selection of potential glo - i enzyme inhibitors .
selection of the proposed inhibitors from the docked set was based on their score , in addition to orientation within the active site and potential chelation between the inhibitor and zinc atom ( considered the main criterion of selection ) .
this type of docking protocol is distinct from other docking programs in that it allows side chains of the active site residues to move with high flexibility . despite being computationally demanding , the flexible docking procedure results in better mimicking of real inhibitor
enzyme binding.36 bulk solvents and chemicals were purchased from sigma - aldrich co. and acros ( thermo fisher scientific , new jersey , us ) via their local agents and utilized with no further purification or distillation .
biological activities of the selected compounds were evaluated by measuring their in vitro inhibitory activities against human recombinant glo - i following the protocol provided by the manufacturer ( r&d systems , inc . ,
the enzyme was reconstituted in our laboratory by dissolving to a concentration of 0.5 mg / ml in sterile , deionized water , stored at 70c , and thawed for use on the day of the test .
test compounds were dissolved in dimethyl sulfoxide to prepare 10 mm stock solution , and absorbance was measured at max of 240 nm for 200 seconds at 25c .
the assay buffer was prepared using 0.5 m sodium phosphate dibasic and 0.5 m sodium phosphate monobasic .
the substrate mixture contained 100 mm glutathione ( freshly prepared ) and 100 mm mg .
the two solutions were combined and added to assay buffer , and the mixture was allowed to stand at room temperature for 15 minutes .
the blank was prepared by mixing assay buffer with substrate mixture , and test compounds were prepared by diluting with assay buffer followed by the addition of human recombinant glo - i into a cuvette at a concentration of 50 m .
discovery studio ( ds ) 3.5 from biovia software inc http://www.3ds.com/products-services/biovia/ ( san diego , ca , usa ) was used for active site analysis , extraction of potential inhibitors from commercial databases ( aldrich ) , and flexible docking .
the crystal structure of glo - i ( accession code : 1qin ) was retrieved from the protein data bank ( pdb ) as our structural model.25
the crystal structure of glo - i , obtained from pdb , was prepared using the prepare protein protocol , in which missing loops and alternate conformations were corrected .
the active site was determined from the cocrystallized ligand bound within , along with the zinc atom .
the glo - i enzyme active site is mapped as three main areas : a highly positive active site mouth containing arginine and lysine , a hydrophobic pocket deep within the active site , and zinc atom coordinated between these two areas.28
the commercially available aldrich database ( containing 250,000 compounds ) from sigma - aldrich co. ( st louis , mo , usa ) was downloaded and converted into a three - dimensional database using the build 3d database protocol in ds .
the database was searched for potential inhibitors of glo - i based on the active site and the function of the ketol group , which can chelate zinc atom.34 the search query was based on two steps : extraction of all compounds containing a ketol group with the potential to chelate zinc atoms , followed by selection of carboxyl - containing compounds from hits retrieved from the first step which were expected to bind to the mouth of the active site .
these steps were performed using the ligand pharmacophore mapping protocol within ds , which aligns and identifies the ligands that map to a pharmacophore . moreover , with application of absorption , distribution , metabolism , excretion , and toxicity ( admet ) profiling and lipinski s and veber s rules , hits were reduced to obtain drug - like compounds and facilitate the process of flexible docking , which is computationally expensive .
final selection of the anticipated inhibitors was based on docking studies in parallel with visual inspection .
the protein active site was determined using the edit and define active site tool available in ds .
the active site was defined by a sphere of 11 radius encompassing the three main areas .
flexible docking protocol in ds 3.5 was used to facilitate selection of potential glo - i enzyme inhibitors .
selection of the proposed inhibitors from the docked set was based on their score , in addition to orientation within the active site and potential chelation between the inhibitor and zinc atom ( considered the main criterion of selection ) .
this type of docking protocol is distinct from other docking programs in that it allows side chains of the active site residues to move with high flexibility . despite being computationally demanding , the flexible docking procedure results in better mimicking of real inhibitor enzyme binding.36
bulk solvents and chemicals were purchased from sigma - aldrich co. and acros ( thermo fisher scientific , new jersey , us ) via their local agents and utilized with no further purification or distillation .
biological activities of the selected compounds were evaluated by measuring their in vitro inhibitory activities against human recombinant glo - i following the protocol provided by the manufacturer ( r&d systems , inc . ,
the enzyme was reconstituted in our laboratory by dissolving to a concentration of 0.5 mg / ml in sterile , deionized water , stored at 70c , and thawed for use on the day of the test .
test compounds were dissolved in dimethyl sulfoxide to prepare 10 mm stock solution , and absorbance was measured at max of 240 nm for 200 seconds at 25c .
the assay buffer was prepared using 0.5 m sodium phosphate dibasic and 0.5 m sodium phosphate monobasic .
the substrate mixture contained 100 mm glutathione ( freshly prepared ) and 100 mm mg .
the two solutions were combined and added to assay buffer , and the mixture was allowed to stand at room temperature for 15 minutes .
the blank was prepared by mixing assay buffer with substrate mixture , and test compounds were prepared by diluting with assay buffer followed by the addition of human recombinant glo - i into a cuvette at a concentration of 50 m .
the glo - i enzyme has been investigated previously by our research group , and three main criteria that contribute to the binding of potential inhibitors have been established . in the present study ,
the crystal structure of glo - i complexed with a substrate analog ( pdb accession code : 1qin ) was employed for active site analysis . the zinc atom localized at the bottom of the active site
the reason behind this assumption is that the zinc atom plays a structural role in the catalytic mechanism of aldehyde detoxification .
structurally , zn has octahedral geometry , coordinating with four amino acids in addition to the inhibitor ( figure 3).25 the second important criterion for selecting glo - i inhibitors is the presence of positively ionizable amino acids , such as arginine and lysine , at the mouth of the active site . the nature of this area has guided the design process to preferably select ligands carrying negatively ionizable groups , such as carboxylic acid .
finally , the hydrophobic pocket located deep within the active site of the enzyme has been utilized in the design process via incorporation of a hydrophobic feature in the final pharmacophore that fits into the pocket .
the next step in the selection of suitable inhibitors of glo - i enzyme was to identify compounds bearing the correct binding features .
many functional groups are known to chelate the zinc atom.34,37,38 we selected the ketol group as a guide , in view of its presence in many natural compounds and lack of association with visible toxicity that is evident with thiol or hydroxamate groups .
a ketol - mapping feature was incorporated into our final pharmacophore ( figure 4 ) .
myricetin , containing a ketol group for chelating the zinc atom , is an established inhibitor of glo - i , and therefore used as a positive control in our enzyme assay .
based on this hypothesis , a query root pharmacophore was built , and the aldrich database was virtually screened to extract the compounds displaying this feature . following the first search step , a refining step was conducted on retrieved hits to further identify compounds possessing carboxylic acid groups , resulting in a collection of compounds possessing both ketol and carboxylic acid groups .
the third feature for consideration is the presence of a hydrophobic moiety , which was investigated manually due to the difficulty of assigning specific groups for the search , since numerous candidate chemical groups are capable of forming hydrophobic interactions . to reduce the number of returned hits and enhance the chances of finding potential inhibitors of glo - i , lipinski s and veber s rules for orally available drug - like compounds ( within ds )
additional restrictions for the selection criteria were imposed prior to docking by filtering compounds that had passed the previous filtration step using the admet profile filter .
the resulting set of filtered compounds were considered effective drug candidates , as they complied with the known rules of safe oral compounds .
successful candidates that passed the harsh filtration criteria were subjected to a semifinal ranking procedure based on docking .
flexible docking is used as a predictor of binding energy and the binding mode ( orientation ) of the final filtered set of compounds .
final selection of the proposed inhibitors for biological evaluation was performed by visual inspection of the chemical structure .
three main features were required for binding ( zbg , cooh , hydrophobic ) in addition to their docking score and binding orientation .
all seven compounds possessed a zbg , carboxylic acid forming a salt bridge at the mouth of the active site , and a hydrophobic group next to the zbg .
the compounds were assayed ( at a concentration of 50 m ) using the method described in the
as shown in table 1 , compounds 1 , 2 , and 3 showed high inhibitory activities , compared to the other four candidates , with compound 2 exhibiting the highest inhibition efficiency ( 76.4% ) at a concentration of 25 m .
compounds 13 with high structural similarity ( apart from the hydrophobic region with different patterns of substitution ) were selected to investigate the importance of hydrophobic interactions .
compound 1 contained an unsubstituted benzene ring , compound 2 had a chlorine atom on the benzene ring as electron - withdrawing group , and compound 3 contained an isopropyl group as electron - donating group .
this variation was in favor of the presence of a chlorine atom at the para position of the benzene ring , which produced a compound at least twice as active as the isopropyl analog and three times as active as the unsubstituted compound .
this could be explained by the fact that the hydrophobic pocket is capable of accommodating more than the benzene ring and electrostatic forces are important , as the cl atom has better activity than the isopropyl group , although both groups are considered classical bioisosteres .
the most active hit was selected as a lead compound for further derivatization and optimization of pharmacokinetic and pharmacodynamic profiles .
ongoing research in our laboratory has focused on generating a robust structure activity relationship that can be utilized in further development and optimization . in silico docking of the proposed compounds
highest scores were obtained with the first three compounds ( 1 , 2 , 3 ) in docking studies , with significant differences in activity , compared with the inactive compounds .
these results have enhanced credibility and confidence in our parametrization of the flexible docking protocol , which may be effectively used in the future to screen other commercial databases for further potential glo - i inhibitors .
compound 2 ( the most active ) is depicted in figure 5 docked within the active site of the enzyme in which the ketol group clearly chelates the zinc atom , the carboxylic acid group forms a salt bridge with the positively ionized mouth , and the hydrophobic pocket is filled with a para - chlorobenzene ring .
the glo - i enzyme has been investigated previously by our research group , and three main criteria that contribute to the binding of potential inhibitors have been established . in the present study ,
the crystal structure of glo - i complexed with a substrate analog ( pdb accession code : 1qin ) was employed for active site analysis . the zinc atom localized at the bottom of the active site
the reason behind this assumption is that the zinc atom plays a structural role in the catalytic mechanism of aldehyde detoxification .
structurally , zn has octahedral geometry , coordinating with four amino acids in addition to the inhibitor ( figure 3).25 the second important criterion for selecting glo - i inhibitors is the presence of positively ionizable amino acids , such as arginine and lysine , at the mouth of the active site . the nature of this area has guided the design process to preferably select ligands carrying negatively ionizable groups , such as carboxylic acid .
finally , the hydrophobic pocket located deep within the active site of the enzyme has been utilized in the design process via incorporation of a hydrophobic feature in the final pharmacophore that fits into the pocket .
the next step in the selection of suitable inhibitors of glo - i enzyme was to identify compounds bearing the correct binding features .
many functional groups are known to chelate the zinc atom.34,37,38 we selected the ketol group as a guide , in view of its presence in many natural compounds and lack of association with visible toxicity that is evident with thiol or hydroxamate groups .
a ketol - mapping feature was incorporated into our final pharmacophore ( figure 4 ) .
myricetin , containing a ketol group for chelating the zinc atom , is an established inhibitor of glo - i , and therefore used as a positive control in our enzyme assay .
based on this hypothesis , a query root pharmacophore was built , and the aldrich database was virtually screened to extract the compounds displaying this feature . following the first search step , a refining step was conducted on retrieved hits to further identify compounds possessing carboxylic acid groups , resulting in a collection of compounds possessing both ketol and carboxylic acid groups .
the third feature for consideration is the presence of a hydrophobic moiety , which was investigated manually due to the difficulty of assigning specific groups for the search , since numerous candidate chemical groups are capable of forming hydrophobic interactions . to reduce the number of returned hits and enhance the chances of finding potential inhibitors of glo - i , lipinski s and veber s rules for orally available drug - like compounds ( within ds )
additional restrictions for the selection criteria were imposed prior to docking by filtering compounds that had passed the previous filtration step using the admet profile filter .
the resulting set of filtered compounds were considered effective drug candidates , as they complied with the known rules of safe oral compounds .
successful candidates that passed the harsh filtration criteria were subjected to a semifinal ranking procedure based on docking .
flexible docking is used as a predictor of binding energy and the binding mode ( orientation ) of the final filtered set of compounds .
final selection of the proposed inhibitors for biological evaluation was performed by visual inspection of the chemical structure .
three main features were required for binding ( zbg , cooh , hydrophobic ) in addition to their docking score and binding orientation .
all seven compounds possessed a zbg , carboxylic acid forming a salt bridge at the mouth of the active site , and a hydrophobic group next to the zbg .
the compounds were assayed ( at a concentration of 50 m ) using the method described in the
as shown in table 1 , compounds 1 , 2 , and 3 showed high inhibitory activities , compared to the other four candidates , with compound 2 exhibiting the highest inhibition efficiency ( 76.4% ) at a concentration of 25 m .
compounds 13 with high structural similarity ( apart from the hydrophobic region with different patterns of substitution ) were selected to investigate the importance of hydrophobic interactions .
compound 1 contained an unsubstituted benzene ring , compound 2 had a chlorine atom on the benzene ring as electron - withdrawing group , and compound 3 contained an isopropyl group as electron - donating group .
this variation was in favor of the presence of a chlorine atom at the para position of the benzene ring , which produced a compound at least twice as active as the isopropyl analog and three times as active as the unsubstituted compound .
this could be explained by the fact that the hydrophobic pocket is capable of accommodating more than the benzene ring and electrostatic forces are important , as the cl atom has better activity than the isopropyl group , although both groups are considered classical bioisosteres .
the most active hit was selected as a lead compound for further derivatization and optimization of pharmacokinetic and pharmacodynamic profiles .
ongoing research in our laboratory has focused on generating a robust structure activity relationship that can be utilized in further development and optimization . in silico docking of the proposed compounds
highest scores were obtained with the first three compounds ( 1 , 2 , 3 ) in docking studies , with significant differences in activity , compared with the inactive compounds .
these results have enhanced credibility and confidence in our parametrization of the flexible docking protocol , which may be effectively used in the future to screen other commercial databases for further potential glo - i inhibitors .
compound 2 ( the most active ) is depicted in figure 5 docked within the active site of the enzyme in which the ketol group clearly chelates the zinc atom , the carboxylic acid group forms a salt bridge with the positively ionized mouth , and the hydrophobic pocket is filled with a para - chlorobenzene ring .
in this research , computer - aided drug design techniques were implemented to identify novel glo - i inhibitors .
thorough investigation of the active site of the target enzyme revealed three areas crucial for effective binding that were used to construct the pharmacophore .
the electrostatic criteria of the three main areas of the active site were fulfilled , that is , a zinc - binding region with a ketol group , a positively ionized active site mouth that can bind carboxylic acid , and finally , a hydrophobic pocket with a lipophilic moiety .
seven compounds were selected based on evaluation of glo - i inhibitory activity in vitro .
the computer - aided drug design techniques used facilitated the rapid and successful identification of a new class of glo - i inhibitors .
we observed a clear correlation between the in vitro results obtained with the selected compounds and their in silico docking scores . | ### Summary:
: backgroundthe glyoxalase system including two thiol - dependent enzymes , glyoxalase i ( glo - i ) and glyoxalase ii , plays an important role in a ubiquitous metabolic pathway involved in cellular detoxification of cytotoxic 2-oxoaldehydes .
tumor cells have high glycolytic activity , leading to increased cellular levels of these toxic metabolites .
the increased activity of the detoxification system in cancerous cells makes this pathway a viable target for developing novel anticancer agents . in this study
, we examined the potential utility of non - glutathione - based inhibitors of the glo - i enzyme as novel anticancer drugs.methodscomputer-aided drug design techniques , such as customized pharmacophoric features , virtual screening , and flexible docking , were used to achieve the project goals .
retrieved hits were extensively filtered and subsequently docked into the active site of the enzyme .
the biological activities of retrieved hits were assessed using an in vitro assay against glo-i.resultssince glo - i is a zinc metalloenzyme , a customized zn - binding pharmacophoric feature was used to search for selective inhibitors via virtual screening of a small - molecule database .
seven hits were selected , purchased , and biologically evaluated .
three of the seven hits inhibited glo - i activity , the most effective of which exerted 76.4% inhibition at a concentration of 25 m.conclusionwe successfully identified a potential glo - i inhibitor that can serve as a lead compound for further optimization .
moreover , our in silico and experimental results were highly correlated .
hence , the docking protocol adopted in this study may be efficiently employed in future optimization steps . |
<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:
: since the birth of chronic dialysis treatment almost 50 years ago , significant technological and medical advancements have influenced the way patients are dialyzed , but the basic questions about what and how much to remove from blood and how and how often to do so are still without an answer .
although major studies have been done to provide the missing evidence , the result has so far been inconclusive .
still , nephrologists have to prescribe dialysis for their patients every day , and while on one hand there is little evidence for superior outcome of one dialysis therapy versus another , treatment personalization and specific prescription for selected patients seems to be a key towards improving outcomes . in a healthcare environment with severe economic limitations ,
the lack of evidence may favour treatment allocation to be dictated by non - medical factors rather than by the experience of the nephrologist or the needs of the single patient .
we therefore decided to undertake an international survey among nephrology professionals to ascertain their view on the best dialysis treatment for different groups of patients and to see how this correlates with the allocation of dialysis therapy today .
a survey instrument including six questions was designed and tested for maximum clarity in a pilot survey .
the first three questions asked for opinions about the best initial dialysis therapy , the best long - term dialysis therapy and the best extracorporeal dialysis therapy .
the fourth question asked for the evidence required to rank dialysis therapies . the answers to these four questions
are described and discussed below , while the remaining questions , being of different nature , will be reported elsewhere .
each question had three to four alternative answers and additionally the option no opinion. only one answer was allowed per question , and when more than one box was marked , the response was placed in the no opinion category .
the response alternatives reflected the common versions of dialysis therapies , given in broad categories and defined so as to avoid confusion and exceptions .
peritoneal dialysis ( pd ) was described as capd / apd ( continuous ambulatory pd / automated pd ) .
haemodialysis ( hd ) was combined with haemodiafiltration ( hdf ) to comprise all forms of extracorporeal dialysis .
the questionnaires were distributed during 2007 , starting at the world congress of nephrology in rio de janeiro , then at the era - edta congress in barcelona , the europd meeting in helsinki , the edtna - erca conference in florence and finally at the asn meeting in san francisco .
a small number of questionnaires were also collected at national meetings in france and australia .
responses were anonymous , but information about country of origin , profession ( physician , nurse , administrator or other ) and experience of dialysis was requested .
we received 6595 responses to our survey ( table 1 ) , with physicians ( 57% ) and europeans ( 59% ) in majority among the respondents . when asked about their experience of dialysis
, 55% of the respondents indicated that they had > 10 years experience and only 5% gave the answer < 1 year .
origin and profession of respondents to dialysis opinion survey , 2007 the first question addressed the initial dialysis treatment for a typical patient , aged 65 years with one comorbidity .
what was considered to be best for this patient among the alternatives : capd / apd , in - centre hd / hdf or home / self - care hd / hdf ?
with self - care therapies among the options , it was assumed that the selected treatment was the patient 's choice .
the result shows a majority of 49% for pd to be considered the best dialysis therapy for incident patients under the given conditions ( figure 1 ) .
the support for pd was in majority in all regions and it was strongest among european physicians , 60% .
not surprisingly , the preference for pd was exceptionally strong among the participants of the europd meeting where 91% of the respondents placed pd as the best initial dialysis treatment .
the other alternatives received the support of 30% for in - centre dialysis and 17% for self - care dialysis from the total group .
the order between the alternatives was the same in all regions and subgroups with exception for the 539 nurses from east europe who placed in - centre dialysis ( 51% ) before pd ( 30% ) .
capd / apd in response to the question what do you consider to be the best initial dialysis treatment for a patient with planned start , today and in the near future? the next question asked about the best long - term dialysis treatment for the majority of patients .
the alternatives were again capd / apd , in - centre hd / hdf and home / self - care hd / hdf . for this question ,
the issue of frequency was introduced and the choice of in - centre treatment had to be given as either 3 times / week or > 3 times / week .
the choice of home / self - care hd / hdf was clearly indicated as > 3 times / week , reflecting a common practice for home hd .
thus , there were four alternatives , two for self - care dialysis and two for in - centre dialysis .
there were also two alternatives for frequent dialysis , one at home and one in - centre .
in all regions , frequent application of home / self - care dialysis was considered the best long - term dialysis treatment , and 34% of the total responses favoured this therapy ( figure 2 ) .
the other three alternatives received similar support of 20% each , with a non - significant difference between them .
home / self - care hd / hdf > 3 times / week in response to the question what do you consider to be the best long - term dialysis treatment for the majority of patients , today and in the near future? the combined result shows that 56% of the nephrology professionals expressed that a self - care administered therapy ( pd or hd / hdf ) is better for the patients than in - centre dialysis .
considering frequency instead , the total result shows that 52% of physicians and nurses working with dialysis had the opinion that hd / hdf administered more frequently than 3 times / week is better for the patients than the current regime of 3 times / week .
if we add the numbers favouring pd , 74% of the respondents clearly said that frequent or continuous dialysis is better than 3 times / week . with 90% of dialysis patients worldwide
being treated with an extracorporeal therapy , the next question focused on the perceived benefits of the major types of this form of dialysis . to avoid confounding of the answers with biocompatibility issues , all alternatives assumed that membranes were synthetic , dialysis fluid was ultrapure and infusion solution , when required , was on - line prepared .
the alternatives were low - flux hd , high - flux hd , high - volume hdf and high - volume haemofiltration ( hf ) .
the total result shows that high - flux hd and high - volume hdf were preferred to a similar extent by 40% each ( figure 3 ) .
hdf was preferred to a greater extent in europe , but moving eastwards the preference for high - flux hd grew and became dominant in asia , and in the americas there was clear differentiation with high - flux hd being named the best by 50% .
the combined support for high - flux hd and hdf was close to 80% in all regions and all subgroups , and this shows an overwhelming belief that dialysis with high - flux membranes is superior to dialysis with low - flux membranes . in fact , only 7% of the total number of respondents indicated low - flux hd as the best option .
share of nephrology professionals who chose the answers high - flux hd ( grey / white ) and high - volume hdf ( black / light grey ) in response to the question what do you consider to be the best extracorporeal form of dialysis? the final question addressed the view of the respondents on the minimum level of evidence they would require to consider one form of therapy superior to another .
the alternatives given were to have hard evidence in the form of improved survival or to have surrogate evidence , which could be improvement of markers such as c - reactive protein or left ventricular hypertrophy .
it could also be to have so - called soft evidence , i.e. studies showing better quality of life .
the assumption was made that all study results should be significant and originate from randomized , controlled studies .
the final option was to have own or colleagues experience as the base for ranking . among the four alternatives , a clear majority responded that they would require hard evidence to consider one form of dialysis superior to another ( figure 4 ) .
this was claimed by 41% of the total , and by over 50% in asia and america .
soft evidence was the choice by 25% of the total and surrogate evidence by only 16% .
hard evidence , i.e. improved survival in response to the question in order to consider one form of dialysis superior to another , what is the minimum level of evidence you would require?
the first question addressed the initial dialysis treatment for a typical patient , aged 65 years with one comorbidity .
what was considered to be best for this patient among the alternatives : capd / apd , in - centre hd / hdf or home / self - care hd / hdf ?
with self - care therapies among the options , it was assumed that the selected treatment was the patient 's choice .
the result shows a majority of 49% for pd to be considered the best dialysis therapy for incident patients under the given conditions ( figure 1 ) .
the support for pd was in majority in all regions and it was strongest among european physicians , 60% . not surprisingly , the preference for pd was exceptionally strong among the participants of the europd meeting where 91% of the respondents placed pd as the best initial dialysis treatment .
the other alternatives received the support of 30% for in - centre dialysis and 17% for self - care dialysis from the total group .
the order between the alternatives was the same in all regions and subgroups with exception for the 539 nurses from east europe who placed in - centre dialysis ( 51% ) before pd ( 30% ) .
capd / apd in response to the question what do you consider to be the best initial dialysis treatment for a patient with planned start , today and in the near future?
the next question asked about the best long - term dialysis treatment for the majority of patients .
the alternatives were again capd / apd , in - centre hd / hdf and home / self - care hd / hdf . for this question ,
the issue of frequency was introduced and the choice of in - centre treatment had to be given as either 3 times / week or > 3 times / week .
the choice of home / self - care hd / hdf was clearly indicated as > 3 times / week , reflecting a common practice for home hd .
thus , there were four alternatives , two for self - care dialysis and two for in - centre dialysis .
there were also two alternatives for frequent dialysis , one at home and one in - centre . in all regions ,
frequent application of home / self - care dialysis was considered the best long - term dialysis treatment , and 34% of the total responses favoured this therapy ( figure 2 ) .
the other three alternatives received similar support of 20% each , with a non - significant difference between them .
home / self - care hd / hdf > 3 times / week in response to the question what do you consider to be the best long - term dialysis treatment for the majority of patients , today and in the near future? the combined result shows that 56% of the nephrology professionals expressed that a self - care administered therapy ( pd or hd / hdf ) is better for the patients than in - centre dialysis .
considering frequency instead , the total result shows that 52% of physicians and nurses working with dialysis had the opinion that hd / hdf administered more frequently than 3 times / week is better for the patients than the current regime of 3 times / week .
if we add the numbers favouring pd , 74% of the respondents clearly said that frequent or continuous dialysis is better than 3 times / week .
with 90% of dialysis patients worldwide being treated with an extracorporeal therapy , the next question focused on the perceived benefits of the major types of this form of dialysis . to avoid confounding of the answers with biocompatibility issues , all alternatives assumed that membranes were synthetic , dialysis fluid was ultrapure and infusion solution , when required , was on - line prepared .
the alternatives were low - flux hd , high - flux hd , high - volume hdf and high - volume haemofiltration ( hf ) .
the total result shows that high - flux hd and high - volume hdf were preferred to a similar extent by 40% each ( figure 3 ) .
hdf was preferred to a greater extent in europe , but moving eastwards the preference for high - flux hd grew and became dominant in asia , and in the americas there was clear differentiation with high - flux hd being named the best by 50% .
the combined support for high - flux hd and hdf was close to 80% in all regions and all subgroups , and this shows an overwhelming belief that dialysis with high - flux membranes is superior to dialysis with low - flux membranes .
in fact , only 7% of the total number of respondents indicated low - flux hd as the best option .
share of nephrology professionals who chose the answers high - flux hd ( grey / white ) and high - volume hdf ( black / light grey ) in response to the question what do you consider to be the best extracorporeal form of dialysis?
the final question addressed the view of the respondents on the minimum level of evidence they would require to consider one form of therapy superior to another .
the alternatives given were to have hard evidence in the form of improved survival or to have surrogate evidence , which could be improvement of markers such as c - reactive protein or left ventricular hypertrophy .
it could also be to have so - called soft evidence , i.e. studies showing better quality of life .
the assumption was made that all study results should be significant and originate from randomized , controlled studies .
the final option was to have own or colleagues experience as the base for ranking . among the four alternatives , a clear majority responded that they would require hard evidence to consider one form of dialysis superior to another ( figure 4 ) .
this was claimed by 41% of the total , and by over 50% in asia and america .
soft evidence was the choice by 25% of the total and surrogate evidence by only 16% .
hard evidence , i.e. improved survival in response to the question in order to consider one form of dialysis superior to another , what is the minimum level of evidence you would require?
today there is no randomized , controlled study of sufficient dimension showing significantly superior survival of a cross - section of patients treated with one dialysis therapy compared to another .
still , this is what a majority of the nephrology community participating in our survey say that they require to consider one therapy better than another .
yet , they have an opinion about what is best for their patients , based on their experience and the evidence available to us today .
it is likely that the type of evidence we would like to obtain is almost impossible to achieve because of the lack of financial support , or simply because the design is too difficult and even a randomized controlled trial may not represent real life. with this in mind , we should consider the opinion of professionals as a tool to identify patterns of practice or ways of thinking and treasure them as important messages coming from everyday experience .
the majority of the respondents in our survey suggest pd as an optimal , initial dialysis treatment .
one of the most often quoted is the superior preservation of residual renal function in pd patients when compared to treatment with conventional haemodialysis .
when used for patients on the waiting list for a transplant , pd has been shown to result in a better graft outcome than hd . for many years
, registry data from north america have shown that survival on pd is better than on hd during the first 23 years of dialysis treatment .
recent data from the usrds suggest that survival on pd now shows further improvement for periods extending beyond the initial years .
starting patients on pd and transferring them to hd in a timely fashion , so - called integrated therapy , has been shown to lead to a survival advantage in comparison to treatment with only hd . finally , treatment with pd delays the need for a functional vascular access , the achilleus heel of all extracorporeal therapies .
the result of our survey confirms these arguments , but all this is in stark contrast to reality .
global information on the treatment mode for incident dialysis patient is not available , but the usrds shows that 6% of the new dialysis patients in 2005 were treated with pd . thus the use of pd and the views on pd
in - centre dialysis , performed 3 times / week , is today used for at least 85% of the prevalent patients worldwide , but only 23% of the 6595 respondents in our survey consider this to be the best long - term dialysis treatment ( figure 5 ) .
instead , self - care dialysis , be it pd or hd , performed at home or in a self - care setting , is indicated as the best form of dialysis treatment for the majority of patients by 56% . in reality ,
even an optimistic estimation of self - care patients worldwide would give a figure of maximum 15% .
a number of reasons can be found to explain this large difference . with a dialysis population of increasing age and comorbidity , the general condition of the patients
patient motivation is another key factor of vital importance for the benefits of a self - care therapy to be realized .
then there are all the non - medical factors against self - care therapies , including physician bias and reimbursement disincentives .
ignorance about the practice and value of self - care therapy among nephrology professionals with little or no experience of this treatment form is often quoted as a cause , but the result of our survey does not support that notion .
other surveys have also shown a positive attitude towards self - care therapies among nephrologists . in 2003 , mendelssohn published the results from a series of surveys among nephrologists in canada , the uk and the usa .
when asked to indicate the preferred distribution of treatment modes for optimal quality of life and wellness , the physicians in the different countries recommended self - care therapy for 4549% of the patients .
, the interest in self - care hd has increased in parallel with a growing number of positive reports on significant clinical benefits from treatment with frequent dialysis , performed as short sessions during daytime or long nocturnal dialysis , 57 times / week .
already today the trips to and from the dialysis unit 3 times / week are a time - consuming burden to patients and with more frequent dialysis the practical disadvantages may offset the therapeutic benefits , unless dialysis can be organized to take place at home .
thus , the realization of more frequent dialysis is closely associated with self - care hd . the positive attitude among nephrology professionals to this form of dialysis therapy
is an encouraging signal to healthcare providers and industry to develop programmes and products that enable more patients to benefit from self - care treatment .
two recent major studies have addressed the issue of high - flux dialysis versus low - flux dialysis in a prospective , randomized , controlled design .
the hemo study found no difference in the primary outcome parameter , all cause mortality , or any of the main secondary outcomes between the groups of 921 patients treated with high - flux membranes and the 925 patients using low - flux membranes .
however , they did find that high - flux dialysis resulted in 20% reduced risk of cardiac death , a secondary combined outcome parameter , and 32% reduced mortality risk in the subgroup of patients treated with dialysis for > 3.7 years before the start of the study .
the mpo study was designed to compensate for some of the shortcomings of the hemo study by only including incident patients and only allowing single use of filters . looking only at patients
whose albumin levels were 4.0 g / dl at the time of enrolment in the study , they found a survival benefit of 37% for the 250 patients treated with high - flux membranes compared to the 243 patients treated with low - flux membranes .
no difference in outcome was seen when all 647 study patients were considered . however , among the 150 diabetic patients , there was also a significant survival benefit from treatment with high - flux membranes .
the result of the mpo study has been widely reported , but its publication as a full paper is still pending .
compared to low - flux dialysis , the increased membrane permeability results in removal of an extended range of solutes and increased volumes of ultrafiltration . because the excess ultrafiltration is compensated by backfiltration of dialysis fluid , high - flux dialysis comprises a certain amount of convective clearance with additional removal of large solutes .
when compared with hdf , we could say that high - flux hd is hdf with a limited amount of convection and without the use of an external substitution solution .
therefore , it is logical to assume that benefits of high - flux dialysis might be extended when moving to hdf , which in the high - volume version provides an additional convective transport , and thus increased removal of larger solutes .
this is also supported by observational data from dopps where hdf patients treated with exchange volumes exceeding 15 l per session showed significantly better survival than hdf patients having a lower volume of convective removal and patients on high - flux dialysis .
other benefits associated with high - flux dialysis , such as improved blood pressure control , anaemia management and nutritional status and reduced levels of 2-microglobulin , are all to a greater extent also reported with hdf . regarding the extracorporeal treatments , there are again large differences between the opinion expressed in our survey and therapies used today .
we estimate that one - third of prevalent patients on hd are still treated with low - flux membranes , at least half of them cellulosic , but only 7% rated low - flux dialysis with synthetic membranes as best for the patients .
the remaining two - thirds are treated with high - flux membranes , the majority in hd mode .
high - volume hdf requires the use of an on - line prepared substitution solution and is therefore only practiced in countries where this form of sterilization is approved by the authorities or recognized by the community .
most european countries have a growing population of patients treated with on - line hdf and its use is spreading in australia and parts of asia . on - line hdf is also starting to be practiced in canada , but is still not approved in the usa .
there are probably close to 50 000 patients on hdf only in europe , the majority in western europe where this therapy is already long - established .
the survey result therefore reflects the practical experience of hdf , with the strongest conviction about its benefits in europe , and this falling as we move eastwards , being replaced by a preference for high - flux hd .
still , the belief in the value of high - flux membranes is equally strong everywhere .
the opinions expressed by the nephrology professionals in our survey closely reflected the ongoing scientific discussion around clinical benefits reported for new therapies and new forms of old therapies .
still , the responders expressed their belief in evidence - based medicine by indicating that a definite ranking of therapies would require evidence of superior survival .
however , it is unlikely that we will ever have such evidence for pd versus hd , for in - centre hd versus home hd , for hd 3 times / week versus hd 56 times / week or for high - flux hd versus high - volume hdf , considering past and ongoing study efforts .
the number of patients and the resources required to conduct adequately powered , prospective , randomized , controlled studies of these issues is probably out of reach for the nephrology community . instead , we will have to look with critical eyes and statistical rigour at the data available to us .
we have not referred to economy once throughout this discussion , although economical issues are certainly among the reasons for reality to be so different from the opinion of the medical professionals about what is best for their patients .
however , while economical limitations may explain why synthetic high - flux membranes are not used for all patients , they do not serve this purpose to justify why self - care dialysis , pd as well as hd , is not used for more patients . furthermore
, economy does not explain why the authorities in some countries do not accept controlled , stepwise ultrafiltration for the preparation of infusion solutions for convective therapies , which would allow a more cost - effective and , by many considered superior form of dialysis therapy , high - volume hdf , to be more widely practiced .
so non - medical issues , besides economy , appear to play a major role in treatment allocation .
the respondents in this survey were not randomly selected and may therefore not represent an international cross - section of nephrology professionals .
they do , however , make up a very large sample of physicians and nurses who attended international congresses in nephrology and dialysis during 2007 , and their responses to our questions are based on long experience of dialysis , over 10 years on average .
their opinions closely reflect what is considered best practice in the nephrology community today and this would likely be a guide to how they would treat the majority of their patients provided non - medical factors did not prevent them . in conclusion
, our survey among 6595 international nephrology professionals showed that the majority considers pd to be the best initial dialysis therapy , while frequently applied , self - care dialysis , when possible in a home environment , is selected as the best long - term therapy .
the best extracorporeal treatment form is dialysis with a high - flux membrane , applied either in hd or in hdf .
these opinions appear to reflect the present view on best clinical practice , but they are far from the clinical reality , where non - medical factors seem to have a strong influence .
the first author ( il ) is a full - time employee of gambro lundia ab . | ### Summary:
: background . there is little evidence for superior outcome of one dialysis therapy versus another .
still , nephrologists have to prescribe dialysis every day .
it is therefore of interest to ascertain the opinion among nephrology professionals regarding which therapy they consider to be the best and to compare this to reality.methods .
we designed a survey addressing these questions and distributed it at five international dialysis and nephrology congresses during 2007.results .
responses were collected from 6595 delegates , 57% physicians and 28% nurses .
peritoneal dialysis ( pd ) was considered the best initial dialysis therapy for a planned start in a typical patient . the dialysis treatment chosen to be best for long - term use
was home / self - care dialysis applied > 3 times / week .
the best extracorporeal form of dialysis among european respondents was high - volume haemodiafiltration ( hdf ) , while the asians and americans gave preference to high - flux haemodialysis ( hd ) .
only 7% preferred low - flux hd .
finally , the respondents were asked what level of evidence they would require to consider one form of dialysis superior to another .
the majority wanted hard evidence , i.e. improved survival , to make such a distinction.conclusions .
the view of nephrology professionals on the value of different dialysis therapies reflects current scientific discussions .
they consider pd to be the best initial therapy and frequent application of home / self - care dialysis to be the best long - term therapy .
high - flux membranes are strongly preferred for any extracorporeal form of therapy , and hdf seems to be the modality of choice among europeans .
the opinions expressed are far from reality , which we interpret to show that non - medical factors have a strong impact on treatment allocation . |
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: thyroid follicular cell tumors arise in rodents from mutations , perturbations of thyroid and pituitary hormone status with increased stimulation of thyroid cell growth by thyroid - stimulating hormone ( tsh ) , or a combination of the two .
the only known human thyroid carcinogen is ionizing radiation .
it is not known for certain whether chemicals that affect thyroid cell growth lead to human thyroid cancer . the u.s .
environmental protection agency applies the following science policy positions : 1 ) chemically induced rodent thyroid tumors are presumed to be relevant to humans ; 2 ) when interspecies information is lacking , the default is to assume comparable carcinogenic sensitivity in rodents and humans ; 3 ) adverse rodent noncancer thyroid effects due to chemically induced thyroid - pituitary disruption are presumed to be relevant to humans ; 4 ) linear dose - response considerations are applied to thyroid cancer induced by chemical substances that either do not disrupt thyroid functioning or lack mode of action information ; 5 ) nonlinear thyroid cancer dose - response considerations are applied to chemicals that reduce thyroid hormone levels , increase tsh and thyroid cell division , and are judged to lack mutagenic activity ; and 6 ) nonlinear considerations may be applied in thyroid cancer dose - response assessments on a case - by - case basis for chemicals that disrupt thyroid - pituitary functioning and demonstrate some mutagenic activity .
required data for risk assessment purposes is mode of action information on mutagenicity , increases in follicular cell growth ( cell size and number ) and thyroid gland weight , thyroid - pituitary hormones , site of action , correlations between doses producing thyroid effects and cancer , and reversibility of effects when dosing ceases.imagesfigure 1figure 2figure 3 |
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: the use of light cure composites for adhesion of orthodontic brackets to the enamel surface has been common in the past decades .
these systems can induce the proper polymerization of light cure composites in 20 to 40 seconds of curing time .
the curing time decreased as the newer composites and light cure systems were introduced . the plasma arc curing system ( pac ) , a system with high light intensity , was first introduced by cacciafesta in orthodontics . in this system , light is emitted from an electricity - conductive gas ( plasma ) which is placed under pressure between two tungsten electrodes .
the pac lamp has a narrower spectrum of 430 to 490 nm and much higher light intensity of 1 200 to 2 200 mw/ cm , so the curing time is significantly reduced . in light curing time studies , the appropriate curing time for composites using the plasma arc system has been recorded as 1 , 2 , 3 , 4 , 5 , 6 , 9 , and 10 seconds .
reported that a plasma arc system with a curing time of 6 seconds has a bond strength and bond fracture similar to that of the halogen light cure systems with the curing time of 20 seconds .
hence , some manufacturers recommend a time of 6 seconds ( 3 seconds of mesial curing and 3 seconds of distal curing ) for the polymerization of the composite layer under the orthodontic brackets using the pac systems . on the basis of these findings
, oesterle believes that curing from two angles on the orthodontic brackets limits the amount of heat produced and reduces the pulpal damage and leads to transference of more light to the bracket base . of course , not all researchers agree on this .
in a 12-month study , sfondrini et al . investigated the causes of orthodontic bracket failure after curing by plasma arc light and halogen light curing on 83 patients .
the results of this study showed that after 12 months , there was no statistically significant difference between failure rate of brackets cured with halogen system and plasma arc system in the maxilla and mandible.signorelli et al .
carried out an in vitro study of the shear bond strength of orthodontic brackets bonded with plasma arc and halogen .
stainless steel brackets were bonded to the teeth using either the halogen system of curing time of 20 seconds or plasma arc system with curing time of 2 , 6 , and 10 seconds through one angle curing .
the results of the study revealed that plasma arc device with curing time of 6 seconds produced bond strength and fracture rate similar to that of halogen system with curing time of 20 seconds.yusoff et al . investigated the effect of angle of the light cure tip on shear bond strength of orthodontic brackets .
he bonded the orthodontic brackets to three groups each containing 30 premolar teeth with led system for 40 seconds at curing angles of 0 , 45 , and 90 , and at the standard distance .
the findings revealed that there was no significant difference in shear bond strength of orthodontic brackets by using led device when curing were done at 0 , 45 , and 90angle.oesterle studied the quick curing of composites using the plasma arc compared to halogen light .
standard brackets were bonded to enamel of pig teeth with three types of orthodontic composites .
the bondings were exposed to halogen light for 40 seconds and to plasma arc light for 3 , 6 , and 9 seconds .
the study showed that the shear bond strength of orthodontic brackets cured with plasma arc increases with curing time .
however , there was no statistically significant difference between bond strength of orthodontic brackets bonded with halogen light at 40 seconds and plasma arc system at 3 , 6 , and 9 seconds . to reduce the excessive heat reaching the teeth , it was recommended to cure the teeth from several different angles at short curing times .
in a 12-month study , sfondrini et al
investigated the causes of orthodontic bracket failure after curing by plasma arc light and halogen light curing on 83 patients .
the results of this study showed that after 12 months , there was no statistically significant difference between failure rate of brackets cured with halogen system and plasma arc system in the maxilla and mandible .
. carried out an in vitro study of the shear bond strength of orthodontic brackets bonded with plasma arc and halogen .
stainless steel brackets were bonded to the teeth using either the halogen system of curing time of 20 seconds or plasma arc system with curing time of 2 , 6 , and 10 seconds through one angle curing .
the results of the study revealed that plasma arc device with curing time of 6 seconds produced bond strength and fracture rate similar to that of halogen system with curing time of 20 seconds .
investigated the effect of angle of the light cure tip on shear bond strength of orthodontic brackets .
he bonded the orthodontic brackets to three groups each containing 30 premolar teeth with led system for 40 seconds at curing angles of 0 , 45 , and 90 , and at the standard distance .
the findings revealed that there was no significant difference in shear bond strength of orthodontic brackets by using led device when curing were done at 0 , 45 , and 90angle .
oesterle studied the quick curing of composites using the plasma arc compared to halogen light .
standard brackets were bonded to enamel of pig teeth with three types of orthodontic composites .
the bondings were exposed to halogen light for 40 seconds and to plasma arc light for 3 , 6 , and 9 seconds .
the study showed that the shear bond strength of orthodontic brackets cured with plasma arc increases with curing time .
however , there was no statistically significant difference between bond strength of orthodontic brackets bonded with halogen light at 40 seconds and plasma arc system at 3 , 6 , and 9 seconds . to reduce the excessive heat reaching the teeth , it was recommended to cure the teeth from several different angles at short curing times .
the question to be answered yet on the basis of dental literature reviewed above is : could similar curing times as above using several curing angles instead of mesial and distal angles via the plasma arc and halogen systems produce a different effect on the shear bond strength of orthodontic brackets ? so , the purpose of the present study was to compare the shear bond strength of orthodontic brackets bonded to enamel using the halogen light and plasma arc light at four angles instead of the conventional two angles to arrive at a more appropriate curing method accompanied by more acceptable shear bond strength for bonding orthodontic brackets .
this was an experimental in vitro study in which the effect of curing methods on shear bond strength of orthodontic brackets is evaluated by using the halogen light curing method compared to the plasma arc method . in this study , considering the p<0.05 , test power of % 80 , s = 3 , and d = 3.1 .
therefore , a total of 60 human maxillary premolar teeth were collected from the patients in need of orthodontic extraction .
the sample teeth were selected according to the following criteria : intact enamel , absence of dental caries or restorations at the buccal aspect of teeth , absence of fracture line due to forceps extraction of the teeth , and absence of any chemical effects of bleaching .
all the sample teeth were then brushed , the debris were removed , and were placed in normal saline solution till the time of experiment .
/ surrey kt 15 se / england ) so that the labial aspect of their crowns was parallel to the shearing force applied by instron device to debond the brackets . to do this ,
a surveyor ( bego , germany ) was used . to standardize the curing conditions and the possibility of light curing from the gingival area to the teeth , the acrylic resin on the buccal aspect of teeth
was formed at 45 degree angle [ figure 1 ] . additionally , to avoid the effect of heat due to hardening of self - cured acrylic resin ,
the curing methods for the four groups were as follows : group 1 : curing with halogen system using the conventional method with a time of 20 seconds ( 10 seconds at the mesial angle and 10 seconds at the distal angle ) .
group 2 : curing with halogen system using the conventional method with a time of 20 seconds ( 5 seconds at the mesial angle , 5 seconds at the distal angle , 5 seconds at the gingival angle , and 5 seconds at the occlusal angle ) .
group 3 : curing with the pac system with a time of 6 seconds ( 3 seconds at the mesial angle and 3 seconds at the distal angle ) .
group 4 : curing with the pac system with a time of 6 seconds ( 2 seconds at the mesial angle , 2 seconds at the distal angle , 1 second at the gingival angle , and 1 second at the occlusal angle ) .
acrylic resin with 45 degree angle on the buccal aspect of teeth to bond the brackets , first the enamel surface was brushed with rubber cap and pumice at low speed handpiece , washed for 10 seconds , and dried with moisture - free air blow for 20 seconds .
then , the teeth were etched with 37% phosphoric acid gel ( 3m / usa ) for 30 seconds and were sprayed with water and air for 30 seconds and finally dried .
transbond xt primer ( 3 m unitek , monrovia , california , usa ) was located on etched enamel surface and formed into a thin layer via the moderate blow of compressed air .
immediately , transbond xt adhesive ( 3 m unitek , monrovia , california , usa ) was used . following this , orthodontic stainless steel brackets ( american
orthodontic / usa ) of maxillary premolars with a 12.31 mm surface were put on the tooth surface . to connect the brackets ,
composite was first placed on the bracket base , and then using special bracket gauge , the brackets were placed on the labial surface in their correct positions . the extra composite flowing out of the bracket base was cleaned .
it should be mentioned that for pac , litex 658 ( dentamerica / taiwan ) and for halogen curing astralis curing light ( model 7 vivadent / lichtenstein ) were used .
light intensity of each curing device was measured three times in the first second using radiometer ( dentamerica / taiwan ) .
the average light intensity of plasma arc system was recorded as 2 125 mw / cm , and that of the halogen system was recorded as 625 mw / cm . following the bonding of brackets , the groups were placed in separate glasses in distilled water for 7 days .
next , the samples were exposed to shearing forces using instron universal testing machine ( dartec / england ) operating at the cross head speed of 1 mm / minute .
to do so , the exerted force was applied to the bonding site between wing and bracket base parallel to the occlusogingival plane and as close as possible to the bracket base .
then , the value for shearing bond strength in mpa was obtained . for statistical analysis
, the data collected were analyzed using the spss16 via the statistics of anova , tukey 's test , and t - test .
the average shearing bond strength for groups 1 through 4 were 10.77 , 16.25 , 12.13 , and 13 .
means of standard deviation and standard error of measurement of the four studied groups in mpa on the basis of anova , there was statistically significant difference between the compared groups ( p = 0.043 ) .
tukey 's test showed that the shearing bond strength of group 2 ( 16.25 mpa ) was significantly higher than that of group 1 ( p = 0.035 ) .
this increase was not statistically significant in the plasma arc group [ p = 0.818 , table 2 ] .
dyadic comparison of means , sds , and significant differences of groups using turkey test comparing the halogen and plasma arc groups , there was no statistically significant difference between group 2 compared to groups 3 and 4 ( p = 0.166 and p = 0.615 ) .
also , there was no statistically significant difference between group 1 compared to groups 3 ( p = 0.898 ) and 4 ( p = 0.403 ) . by using t - test
, there was no statistically significant difference in the overall comparison of halogen groups and plasma arc groups , i.e. , total curing of two halogen groups and total curing of two plasma arc groups [ p = 0.725 , table 3 ] .
comparison of means , sds , and standard error of measurement in the halogen groups and plasma arc groups
halogen light cure device must cure each bracket for 20 to 40 seconds and this is very time consuming for all of the teeth .
the plasma arc system has been introduced as a device with high intensity of light in recent years .
this device was first proposed by cacciafesta and then by others to replace the halogen light system .
the high intensity of light in this system ( 1 200 - 2 100 mw / cm ) reduces the curing time of composites , this being the main advantage of this device over others . in this study ,
two systems of halogen and plasma arc light were used to bond the orthodontic brackets .
the purpose of this study was to compare the shear bond strength of orthodontic brackets bonded to enamel in two- and four - directional curing angle and by using of the plasma arc and halogen light systems .
had previously asserted that shear bond strength of plasma arc with the total time of 6 seconds at two - directional mesial and distal curing was similar to that of halogen light with the total time of 20 seconds of two - directional mesial and distal curing .
it should be mentioned that the plasma arc system can produce a clinically acceptable bond strength at 2 seconds and 4 seconds , yet this bond strength ( specially at time of 2 seconds ) is significantly lower compared to the curing at 4 seconds . in the present study ,
the bond strength value from first to last group was 10.76 mpa -16.25 mpa-12.13 mpa - 13.85 mpa , respectively .
the anova showed a statistically significant difference among the groups . in dyadic comparison of the groups ,
on the basis of the findings of this research , it can be concluded that the four - directional curing to brackets can induce the better diffusion of light energy to the underlying area of the bracket base . in groups 3 and 4 ,
the bond strength was higher with four - directional curing compared to two - directional curing ; yet , it was not statistically significant .
this , in turn , can lead to the better polymerization of composites and ultimately higher bond strength of brackets .
so , increasing the curing periods from 2 to 4 and the consequent increased bond strength of orthodontic brackets are justifiable in this study .
the reported bond strength values in this study for groups 1 ( halogen light system with two curing periods of 10 seconds duration ) and 3 ( plasma arc system with two curing periods of 3 seconds duration ) are consistent with klock et al .
's values obtained with the same device , curing periods , and time being 11.15 mpa for halogen light and 12.02 mpa for plasma arc , respectively .
furthermore , in a study by oesterle , he used two curing periods of 3 seconds duration ( 3 seconds mesial and 3 seconds distal ) with the plasma arc system and reported the obtained bond strength value as 20.7 8.9 mpa after 24 hours .
's and osterle 's studies can be attributed to the type of composite used , i.e. , klock et al .
comparing the two halogen and the two plasma arc groups , there was no statistically significant difference among them .
our findings in this study are consistent with that of other researchers regarding bond strength values between the halogen and plasma groups . on the whole , increasing the curing periods resulted in a relative increase in the obtained bond strength values in both the halogen and the plasma arc group ; yet , the bond strength mean was only higher significantly in group 2 ( 16.25 mpa ) compared to group 1 ( 10.76 mpa ) , but there was no statistically significant difference between groups 3 and 4 .
the increased shear bond strength due to more curing periods in the halogen group is justifiable ; the cause may be the fact that the 20 seconds period of curing time of halogen system included four curing periods of 5-second duration , while the 6 seconds curing time of the plasma arc included two curing periods of 2 seconds and two periods of 1-second duration , respectively
. may be the 1-second curing period of plasma arc has not been effective on bond strength . in many articles ,
the curing time for plasma arc system and halogen light has been designed as two mesial and distal curing periods to reduce pulpal effect of the heat produced by the curing systems since the increased heat following the light cure composite polymerization is either due to the absorbed energy during curing or due to the polymerization process , the former being of more significance .
therefore , increasing the curing periods from 2 to 4 can not only increase shear bond strength , but also prevent pulpal damage , for according to studies by zac , cohen , and scheinin , a pulp temperature of higher than 42.5c may cause irreversible pulpal damage . in a study by haning and bott ,
the use of plasma arc for 10 seconds and halogen light for 40 seconds cause 7.8c and 5.59c increase in the pulp temperature , respectively .
though this temperature and time lies within a range that can cause pulpal damage , this study has been carried out on class ii restorations and can not be properly compared to orthodontic brackets bonding .
the use of such curing periods in different areas to reduce the pulpal damage produced by heat was also confirmed by oesterle .
he believed that this procedure can lead to better diffusion of heat or light energy to the base of bracket , i.e. , the theory behind the present study .
he applied 3 seconds curing periods for plasma arc and in three curing periods including 3 seconds-6 seconds ( 3 seconds mesial , 3 seconds distal ) 9 seconds ( 3 seconds mesial , 3 second distal , and 3 second occlusal ) curing period with halogen light and concluded that the plasma arc with curing periods of 6 seconds and 9 seconds produces a bond strength value similar to that of the halogen light with a curing time of 40 seconds .
he also concluded that increasing the curing periods at different sites reduces the pulpal effect of the plasma arc on the teeth .
yet , he did not compare his own opinion on the effect of light energy on bracket 's base to the effect of multiple curing periods on shear bond strength of orthodontic brackets .
mention should be made of the fact that in the present study , shear bond strength values of the four groups above were higher than the least standard value needed in orthodontics , this value being 6 - 8 mpa . in the present study , to ensure complete curing of composite under the orthodontic brackets , a wedging of 45 was done on the gingival side of acrylic resin to simulate in vivo conditions . in the study by yussof et al .
, the effect of the angle of the curing tip on the bond strength of orthodontic brackets was studied and the composites were cured at three different angles of 0 , 45 , and 90 from a 3 mm distance .
the study showed that there was no statistically significant difference between bond strength of orthodontic brackets and light cure tip angulations of 0 , 45 , and 90. of course , in this study , changing the position of the light cure tip from one area to another was considered and just the curing tip angle in one site was investigated . in the present study , yet , to standardize the experiment conditions , just the curing at 45 was used with light cure curing . in this study
, the shear bond strength of orthodontic brackets was evaluated via instron device after 120 hours of maintenance in distilled water , since , according to hajrassie and kheir and mccourt et al . , the shear bond strength value obtained after 24 hours of bonding of the brackets was not significantly different from that obtained after 30 days .
seemingly , more studies should be carried out on the effect of increasing curing periods at different sites of the oral cavity on the bond strength of orthodontic brackets bonded with light cure systems .
regarding the limitations of this in vitro study , since there was no statistically significant difference between shear bond strength of orthodontic brackets bonded to teeth with halogen light and that of brackets bonded with plasma arc , the use of plasma arc system is preferable due to shorter curing time of bonding . on the other hand
, increasing the curing periods from 2 to 4 ( with equal times ) led to a significant increase in bond strength with halogen light system . | ### Summary:
: background : reduced time and appropriate bond strength of brackets is one of the most important aspects of orthodontic treatments .
prolonged halogen light curing for bonding of brackets is undesirable , so the purpose of this study was to compare the shear bond strength of brackets bonded with halogen light and plasma arc system.materials and mehods : this was an experimental in vitro study .
a total of 60 intact premolar teeth were collected and divided into four groups .
stainless steel orthodontic brackets were bonded to them . in groups 1 and 2 , curing was done using halogen light given for 20 seconds from two and four angles . in groups 3 and 4 , curing was carried out using the plasma arc system for 6 seconds from two and four angles .
the shear bond strength was recorded by instron .
the statistics of anova , tukey 's test , and t - test were used in data analysis.results:there was a statistically significant difference in shear bond strength among the four groups ( p = 0.043 ) and between group 1 with group 2 ( p = 0.035 ) . yet
, there was no statistically significant difference between brackets bonded with plasma arc and those bonded with halogen light or between the two groups of plasma arc.conclusion:using the plasma arc system is superior to other methods due to reduced curing time .
also , since in using the halogen light system , an increase in curing periods from different angles resulted in a significant increase in shear bond strength ; it is advisable to apply the halogen light from different angles . |
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: aptamers are in vitro selected nucleic acid molecules that bind to a broad range of targets with high affinity and specificity . the basic isolation process , termed
systematic evolution of ligands by exponential enrichment or selex ( ellington and szostak , 1990 ; robertson and joyce , 1990 ; tuerk and gold , 1990 ) , utilizes a large initial pool of randomized nucleic acids from which high affinity binders are isolated and enriched through subsequent rounds of selection ( figure 1 ) .
different in vitro isolation strategies can be used to generate aptamers against many diverse targets under different selection and counter selection conditions , leading to facile identification of aptamers that bind targets ranging from a few atoms ( small molecules ) to many atoms ( macromolecules ) to intact cells and viruses .
most aptamers characterized to date are single stranded dna or rna molecules ranging from 20 to 90 bases , although longer aptamers have been generated .
these single stranded polynucleotide sequences can fold into a variety of secondary structural elements , including double stranded rna ( dsrna ) or dsdna , stem loops , pseudoknots , kinks , and bulges , providing multiple recognition surfaces for target binding . the selex process .
the resulting pool of rna is subjected to ( a ) counter selection and/or ( b ) selection by filter binding .
( c ) selected rna is recovered , reverse transcribed , and amplified by pcr .
( d ) the resulting rna pool is subjected to another round of selex for enrichment or cloned and sequenced .
aptamers are often compared to antibodies , due to the high specificity for their targets generated through stringent in vitro selection .
however , aptamers have notable advantages over antibodies , including low immunogenicity and the potential for chemical derivatization to enhance in vivo stability and bioavailability ( jellinek et al . , 1995 ; chelliserrykattil and ellington , 2004 ; kato et al . , 2005 ) .
the aptamer selection process can be carried out in as little as 24 weeks , which is significantly shorter compared to antibody development ( months ) . since the initial description of the selex process over two decades ago , general principles guiding the selection process have remained largely unaltered .
however , modifications to the original process now allow for highly efficient and extremely stringent selection strategies to be employed against a diverse array of targets .
identified aptamers can be further optimized using biased libraries that result in aptamer subpopulations with higher specificity and/or affinity and other desirable characteristics , such as membrane permeability .
coupling selex methods with other techniques , such as capillary electrophoresis and surface plasmon resonance ( spr ) , can reduce the number of selection rounds and shorten the period for aptamer discovery against a given target .
in addition , facile generation of modified aptamers allows for coupling of diagnostic tags , which can extend the use of aptamers through prolonged lifetimes in serum .
given the traditional comparisons with antibodies , the utility of aptamers in the clinic is taking longer than anticipated from the outset of discovery .
nonetheless , with the 2004 fda approval of pegaptanib , an aptamer - based drug used to treat wet age - related muscular degeneration , and others in the pipeline , it is clear that aptamers will continue to contribute to our understanding of normal and aberrant cellular processes as well as disease treatment .
recent comprehensive reviews highlight advances in basic research ( james , 2001 , 2007 ; syed and pervaiz , 2010 ; sun et al . , 2011 ) and clinical settings ( bunka and stockley , 2006 ; gopinath , 2007 , 2008 ; meyer et al .
the host viral interface has become an increasingly popular target for aptamers because interactions between nucleic acids and proteins are critical to viral replication ( figure 2 ) .
although not a prerequisite , targeting nucleic acid binding proteins by aptamers has a high probability of success due to the presence of basic surface charges on most nucleic acid binding proteins .
below we summarize select studies in order to highlight the use of aptamers against viral components and discuss challenges and future prospects of the field .
key steps in the viral replication cycle are targets for aptamer development . examples of viral proteins targeted by aptamers are identified in red .
aptamers provide an alternative method for the development of therapeutic agents to counter viral infections .
aptamers can be used to inhibit viral infectivity at any stage in the viral replication cycle , including viral entry , which has the potential to prevent initial infection .
the development of aptamers against the human immunodeficiency virus hiv-1 has been of interest for drug discovery . in order to target hiv entry into helper t - cells , aptamers generated against hiv glycoprotein 120 ( gp120 ) competes with the hiv co - receptor , ccr5 .
the aptamer binding site is located in a highly conserved region of gp120 , allowing neutralization of a broad range of hiv isolates by disrupting the gp120ccr5 interaction ( dey et al .
, 2005a , b ) . binding to a conserved region of gp120 is critical due to the propensity of hiv to undergo mutagenesis that results in drug - resistance .
the anti - gp120 aptamer has not been approved for clinical trials , but has been used as a basis for developing chimeric aptamers ( neff et al . , 2011 ; wheeler et al . , 2011 ; zhou et al . , 2011 )
coupling of sirna and the anti - gp120 aptamer through phi29 packaging rna combines two functions ( zhou et al . , 2011 ) .
the anti - gp120 aptamer has an inhibitory effect , while sirna downregulates the expression of its target .
aptamer generation against human cytomegalovirus ( hcmv ) particles was carried out without prior information on specific targets ( wang et al . , 2000 ) .
two aptamers , l13 and l19 , were isolated that inhibit hcmv plaque formation and growth .
the antiviral activity of l13 and l19 aptamers identified hcmv glycoproteins b and h as targets , respectively , by binding to the glycoproteins and blocking viral entry .
viral rna - dependent rna polymerases have been a common target because viral polymerases use rna as the template during genome replication .
for example , the hepatitis c virus ( hcv ) polymerase non - structural protein 5b ( ns5b ) , is required for transcribing the hcv genome and has been used to generate both anti - ns5b rna and dna aptamers ( biroccio et al .
both sets of aptamers have been shown to bind to ns5b with high affinity and inhibit polymerase activity .
the mechanism of inhibition of the anti - ns5b rna aptamer is non - competitive with regards to the template rna , and mutagenesis studies revealed that a basic patch within the thumb domain of ns5b is the aptamer binding site ( biroccio et al . , 2002 ) .
only one anti - ns5b dna aptamer inhibits replication by competing with the rna template ; the other inhibits through a non - competitive mechanism in which initiation and post initiation events are disrupted .
rna aptamers capable of inhibiting ns5b polymerase activity were further optimized through the use of deletion clones and point mutagenesis , which identified a gc - rich motif and a stem - loop with a bulge as important features for aptamer binding to ns5b ( kanamori et al . , 2009 ) .
in the context of hiv pathogenesis , viral reverse transcriptase ( rt ) converts the single stranded rna ( ssrna ) viral genome into dsdna .
rna aptamers that target hiv - rt effectively inhibit the synthesis of cdna ( tuerk et al . , 1992 ) .
the ligand 1.1 aptamer targeting hiv - rt is postulated to reduce adverse side effects , a main concern with current hiv - rt drugs , such as 3-azido-3-deoxythymidine ( azt ) and dideoxyinosine . moreover , by targeting an enzyme early in the hiv-1 replication cycle , the likelihood that mutations will arise resulting in drug - resistance should diminish .
inhibition of protein translation is a key host defense mechanism against viral infections since viruses are completely dependent on the host machinery for protein synthesis .
however , viruses have developed various means to evade host defenses and hijack the host translational machinery .
for example , the hcv mrna has an internal ribosome entry site ( ires ) , a structured region within the mrna that binds the ribosome and initiates cap - independent translation , allowing hcv to circumvent the requirement for host initiation and elongation factors .
aptamers targeting the hcv ires inhibit ires - dependent translation of hcv proteins ( aldaz - carroll et al . , 2002 ; kikuchi et al . , 2003 , 2005 ; da rocha gomes et al . , 2004 ) .
furthermore , many of these hcv ires aptamers inhibit translation both in vitro and in vivo , highlighting the potential therapeutic value of these aptamers since they target rna secondary structure that is characteristic of select viral mrnas but not host mrna . therefore , such selection may result in a reduction of negative side effects .
the viral inhibitory properties of hcv anti - ires aptamers can be enhanced through conjugation to other aptamers , which target different binding sites within the hcv ires .
this results in a conjugated anti - ires aptamer that binds the hcv ires with a higher affinity and is functionally more effective than the unconjugated aptamers ( kikuchi et al . , 2009 ) .
alternatively , hcv anti - ires aptamers can be coupled to the hammerhead ribozyme to prevent translation .
the chimeric rna molecule , hh363 - 50 , inhibits ires - dependent translation in vitro likely through disruption of 80s complex formation with no effect on ires - independent translation .
hh363 - 50 also reduced the level of hcv rna due to the ribozyme activity of the molecule ( romero - lopez et al . , 2009 ) .
early and reliable detection of pathogens is a critical step in the successful treatment of infection . due to many potential advantages aptamers
these studies include simple modifications to the enzyme linked immunosorbent assay ( elisa ) as well as more complex diagnostic systems , such as those that use inhibitory aptamers to suppress multi turnover enzymes ( zhou et al . , 2010 ) .
the influenza a virus hemagglutinin ( ha ) and neuraminidase ( na ) antigens are glycoproteins found on the surface of the viral particle , and serve important roles in host membrane fusion .
a number of aptamers have been isolated against influenza a ha that inhibit viral infectivity ( jeon et al .
, 2004 ; misono and kumar , 2005 ; gopinath et al . , 2006 ; dhar and datta , 2009 ; park et al . , 2011 ) .
in addition to disrupting viral ha - mediated membrane fusion , the p30 - 10 - 16 aptamer can distinguish between closely related influenza a strains .
this aptamer property is novel , considering that most monoclonal antibodies against ha have been unsuccessful at differentiating among influenza subtypes .
although initial studies were carried out by spr - based detection , coupling of these aptamers to fluorophores or other signaling molecules could provide facile detection of virus subtypes .
development of these aptamers for viral subtype diagnostics will provide a significant advancement in our ability to differentiate highly pathogenic influenza strains from those that are less virulent and will likely yield important insights into its mechanism of action . the hepatitis b virus ( hbv ) surface antigen ( hbsag )
is found on the membrane of hbv - infected hepatocytes . a fluorescently labeled aptamer targeting hbsag , hbs - a22 ,
use of fluorescence microscopy showed that that anti - hbsag aptamer bound to the hbsag - positive cell line ( hepg2.2.15 ) but not to the hbsag - negative cell line ( hepg2 ) .
these results establish the use of aptamers for imaging , but also provide the first hbv specific antigen aptamer that could be used for early detection and treatment of hbv - infected cells ( liu et al . , 2010 ) .
aptamers can also function as diagnostic tools when coupled to existing biosensors ( davis et al .
, 1998 ; jhaveri et al . , 2000 ; fang et al . , 2001 ; osullivan , 2002 ) .
biosensors utilize a biological recognition element , such as aptamers , and a transducer for easier detection and quantification .
an aptamer - based biosensor , or aptasensor , was isolated against the trans - activator of transcription ( tat ) of hiv-1 , which is important for regulating the early phases of hiv-1 infection ( chang et al . , 1997
the tat aptasensor was generated by immobilizing the aptamer on a piezoelectric quartz - crystal , the transduction component of the aptasensor .
comparison of the tat aptasensor to a corresponding immunosensor that uses an anti - tat monoclonal antibody showed that the two biosensors are similar in terms of sensitivity and reproducibility ( minunni et al . , 2004 ) .
a multicomponent reporter system consisting of an inhibitory aptamer bound to a restriction endonuclease and a target complement / trigger system was successful in differentiating dengue virus serotypes ( fletcher et al .
one of the key advantages of this method is that the same aptamer / enzyme complex can be used since only the nucleic acid complement / trigger needs modification to detect new targets . such a system can be more sensitive due to the multi - turnover nature of the endonuclease .
further development of these aptasensors and incorporating more stable chemical derivatives will likely overcome some of the limitations of current aptasensors .
in addition to diagnostic and therapeutic applications , aptamers can be used as laboratory reagents in a number of biochemical and cell - based assays , similar to antibodies .
aptamers have key advantages over antibodies in that they often have higher affinity and specificity for their targets with some binding constants ( kd ) < 1 nm , which results in an enhanced signal - to - noise ratio .
additionally , aptamers can be generated against almost any target ranging from small organic molecules to proteins to whole cells ( jayasena , 1999 ) , and they are often times smaller than antibodies ( 730 kda for aptamers vs. 150 kda for antibodies ) allowing them to bind regions inaccessible to antibodies . by utilizing aptamers that disrupt protein protein interactions , one can begin to dissect and characterize cellular pathways .
the human t - cell leukemia virus type 1 tax protein is a trans - activator that regulates the expression of various viral and cellular genes .
tax can not directly bind dna in the absence of certain host transcription factors , suggesting that protein protein interactions are essential for tax function .
the yt1 aptamer disrupts tax interactions with the cyclic amp - response element binding protein ( creb ) and nf-b , but not serum response factor ( srf ) , all of which are known to interact with tax proteins ( tian et al . , 1995 ) .
these results suggest that the creb and nf-b binding interfaces on tax may potentially overlap or are in close proximity , whereas the srf binding site occupies a different surface on tax .
assembly of the viral nucleocapsid ( nc ) requires multiple protein protein and protein nucleic acid interactions .
the hiv nc is a highly conserved protein that plays a key role in rna encapsidation and viral replication , and specifically binds viral genomic rna through the psi sequence .
an aptamer generated against nc competes with the psi sequence and prevents proper encapsidation of the viral genome , which likely inhibits proper packaging of the genomic rna ( kim et al . ,
other hiv-1 nc aptamers against the hiv-1 gag protein bind the matrix and the nc domains of gag and reduced hiv replication in cultured cells .
the inhibitory effect of these aptamers was not due to a defect in virion release but the downregulation of intracellular gag protein and mrna .
a subset of aptamers which specifically bound nc competes with the psi packing signal of hiv-1 , and disrupts interactions between gag and viral rna ( ramalingam et al . , 2011 ) . unlike other aptamers that inhibit early stages in viral infection ,
the nc aptamer targets events that occur after viral entry , and therefore , allows one to study the intracellular effects of viral infection .
using aptamers to specifically target and modulate functions of proteins within cellular pathways or the viral replication cycle can provide invaluable information about these respective systems . nonetheless , an additional advantage of using aptamers to investigate cellular signaling is the ability to selectively turn the aptamers on and off with effectors .
further advances in the spatial and temporal regulation of aptamers will be important for enhancing our understanding of viral / host interactions .
the potential regulation of aptamers with effector molecules is highlighted by vuyisich and beal ( 2002 ) in the regulation of formamidopyrimidine glycosylase ( fpg ) , a bacterial enzyme involved in dna repair .
a modified selex protocol was used where rna - bound fpg was treated with neomycin in order to elute the bound rna .
the fpg aptamer inhibited fpg activity , but the functionality was restored in the presence of neomycin .
( 2002 ) utilized anti - sense rna in order to regulate the function of an aptamer targeted against the blood coagulation factor ixa .
the anti - sense rna base pairs to complementary regions within the aptamer and disrupts aptamer function .
the factor ixa aptamer and anti - sense rna antidote pair was an effective , reversible anticoagulant and shows potential for clinical application .
many viral proteins bind nucleic acids , although not a required characteristic , makes viruses good targets for aptamer development . as outlined above , aptamers have been used in a variety of studies to characterize and counter host viral interactions , including targeting individual viral components or whole cells .
a significant advantage of the aptamer technology lies in its ability to identify aptamers against a given target without a priori knowledge of the exact site or target . with limited information on the binding site
, aptamers can be generated toward a given target and subsequently tested for regulatory activity either in vitro or in vivo .
similarly , aptamers can be used in target validation , where judicious use of aptamers can provide distinct advantages .
protein interfaces and to validate traditional targets for small molecules , such as enzyme active sites .
current selection of small molecules toward known targets often depend on a variety of factors , including the availability of validating functional assays , structural and biochemical data , prior to initiating drug discovery efforts , which consume large amounts of time and resources .
in contrast , one can develop aptamers with a fraction of the cost and time in a laboratory setting .
it is interesting to note that most aptamers form unusual and dynamic conformations that can potentially allow aptamers to target protein
however , in many of the examples reviewed , there is limited knowledge on the structural and biochemical aspects of these aptamer / target interactions , and available data are primarily restricted to secondary structure predictions or mapping .
the addition of structural and biochemical studies of aptamer / target pairs can enhance the utility of these aptamers by providing new information on the aptamer / target interfaces and by providing information for structure - based optimization of aptamers .
continual development and optimization of multifunctional , chimeric aptamers , and aptamer libraries for strain specific viral identification will lead to more broadly applicable therapeutic and diagnostic applications in the future .
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:
: aptamers generated from randomized libraries of nucleic acids have found utility in a wide variety of fields and in the clinic .
aptamers can be used to target both intracellular and extracellular components , including small molecules , proteins , cells , and viruses . with recent technological developments in stringent selection and rapid isolation strategies ,
it is likely that aptamers will continue to make an impact as useful tools and reagents .
although many recently developed aptamers are intended for use as therapeutic and diagnostic agents , use of aptamers for basic research , including target validation , remains an active area with high potential to impact our understanding of molecular mechanisms and for drug discovery . in this brief review
, we will discuss recent aptamer discoveries , their potential role in structural virology , as well as challenges and future prospects . |
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: calciphylaxis is a rare , but life - threatening disease characterized by progressive cutaneous necrosis and ulceration secondary to small- and medium - sized vessel calcification .
it is also known as the vascular calcification - cutaneous necrosis syndrome. end - stage renal disease and hyperparathyroidism have been considered as major causes for calciphylaxis , but many other conditions can be associated with calciphylaxis . chronic inflammation and prolonged corticosteroid administration have recently been reported as calciphylaxis - inducible conditions in non - uremic cases [ 5 , 6 ] , although their precise mechanism has been poorly understood .
many kinds of management for calciphylaxis have been tried , but there is still no effective treatment available .
the main cause of death in calciphylaxis patients is fatal bacterial infection due to the destruction of the cutaneous defense system .
the total mortality rate has been reported to range from 60 - 80% . on the other hand , polyneuropathy , organomegaly , endocrinopathy , monoclonal gammopathy , and skin changes ( poems )
syndrome is a rare multisystem disorder caused by plasma cell dyscrasia , often requiring long - term corticosteroid therapy .
vascular endothelial growth factor ( vegf ) has been implicated in the pathogenesis of poems syndrome and the serum level of vegf is parallel to the disease activity .
as included in the disease acronym , skin changes are one of the major features in poems syndrome ; they are hyperpigmentation , skin thickening , hypertrichosis , cherry angioma , white nails , clubbing , flushing and peripheral cyanosis .
to our knowledge , however , only one case with poems syndrome has been reported to be associated with calciphylaxis .
here we report a japanese patient who developed calciphylaxis 11 years after the onset of poems syndrome .
a 57-year - old male with an 11-year history of poems syndrome was admitted to our hospital because of painful skin ulcers and edema .
the diagnosis of poems syndrome had been made on the basis of polyneuropathy , lymphadenopathy , gynecomastia , monoclonal gammopathy ( igg type ) , skin pigmentation and hypertrichosis with elevated serum vegf levels .
biopsy specimens from his sural nerve tissue showed axonal degeneration with myelin ovoid and endoneurial edema , in agreement with the histological diagnosis of polyneuropathy associated with poems syndrome .
cervical lymph node biopsy showed the finding compatible with hyaline vascular type castleman 's disease .
bone survey did not reveal any sclerotic or lytic bone lesions , and bone marrow aspiration showed normal or slightly hypercellular marrow without plasma cell proliferation . in spite of corticosteroid therapy with additional intravenous immunoglobulin therapy or oral azathioprine therapy , the disease gradually worsened .
the patient refused treatment with conventional chemotherapy or high - dose melphalan chemotherapy combined with peripheral blood stem cell transplantation for plasma cell dyscrasia .
he first noted an ulcer on his left thigh 6 months before the present admission .
the skin lesion was resistant to conventional skin care and treatment , and worsened gradually .
he showed severe and painful ulcers with gangrene on his bilateral thighs on admission ( fig .
serum calcium concentration revised with albumin level , phosphorus concentration and parathyroid hormone level showed normal values .
the concentration of serum vegf was markedly higher than observed earlier ( table 1 , fig .
2 ) . though immunological examination showed slightly elevated anti - cardiolipin antibody levels , lupus anticoagulant level was normal .
protein c and protein s , as well as other coagulation regulatory factors , were within normal levels .
disseminated calcification of vascular walls , especially in cutaneous vessels , was demonstrated with x - ray photography ( fig .
no calcification was evident on the x - ray photograph of the same site 2 years before the present admission .
a biopsy specimen from the skin ulcer on his left thigh proved proliferation of endothelial cells and calcification in several cutaneous small - sized vessels ( fig .
according to clinical features , radiographic and histological findings , the diagnosis of calciphylaxis was confirmed . to prevent the progression of poems syndrome and calciphylaxis , combination therapy using melphalan ( 0.22 mg / kg / day , for 4 days ) , dexamethasone ( 40 mg / day , for 4 days ) and the anti - vegf agent , thalidomide ( 100 mg / day , daily use ) , was started .
the serum vegf concentration drastically decreased after the initiation of this combination therapy , but the calciphylaxis remained uncontrollable .
his skin ulcerations extended to the bilateral legs and trunk in a few months ( fig .
1b ) . additional hyperbaric oxygen ( hbo ) therapy and bisphosphonates failed to repress calciphylaxis .
most cases with calciphylaxis reported so far have been associated with end - stage renal disease and secondary hyperparathyroidism
. however , there is growing evidence that this entity is associated with several non - uremic diseases such as malignancy , alcoholic liver disease , collagen - vascular diseases , diabetes and inflammatory bowel disease .
the possible risk conditions or trigger factors for calciphylaxis in non - uremic diseases include chronic inflammatory state , systemic hypercoagulable state , and chronic immunosuppressive state . to date ,
de roma et al . reported a 46-year - old italian woman who developed calciphylaxis 34 months after the diagnosis of poems syndrome .
and ours lacked the well - known risk conditions such as renal failure , hyperparathyroidism , or clotting disorders .
although the vegf values were not described in that case , a high dose of corticosteroid was used .
these cases indicate that poems syndrome can be an independent risk condition for the development of calciphylaxis in certain circumstances .
vascular calcification is thought to result from imbalance between bone deposition and resorption [ 12 , 13 ] .
various bone - regulating proteins are involved in the process of vascular calcification [ 12 , 13 ] .
rankl ( receptor activator of nuclear factor-b ( nf-b ) ligand ) and its antagonist , osteoprotegerin ( opg ) , play a critical role in bone remodeling [ 12 , 13 ] .
the activation of rank - mediated nf-b pathway causes osseous mineral loss and extraosseous ( vascular ) mineral deposition .
. chronic deregulation of vegf and proinflammatory cytokines has been implicated in the pathogenesis of poems syndrome . in particular , the level of serum vegf is widely used as a marker of disease activity in poems syndrome .
interestingly , it is reported that vegf regulates calcification in cultured vascular smooth muscle cells , or other type of cells , in cooperation with bone morphogenetic proteins ( bmps ) [ 14 , 15 ] .
furthermore , corticosteroid , as well as parathyroid hormone , is known to activate rank - mediated nf-b pathway and to inhibit opg .
thus , a long - term corticosteroid administration is likely to promote osseous mineral loss and vascular calcification .
several proinflammatory cytokines , namely interleukin-1 and tumor necrosis factor - a , may promote vascular calcification by activating rank - mediated nf-b pathway .
taken together with these evidences , it is very likely that poems syndrome is a possible risk condition for calciphylaxis . in conclusion , we report the second case of poems syndrome complicated with calciphylaxis .
the precise causes for calciphylaxis in our patient remain unsolved , but we speculate that the sustained elevation of serum vegf levels and the long - term administration of corticosteroids could contribute to the development of calciphylaxis . our trial with an anti - vegf agent failed to control calciphylaxis , but the initiation of anti - vegf therapy in the earlier stage of the disease could prevent or delay the development of calciphylaxis . | ### Summary:
: calciphylaxis is a vascular calcification - cutaneous necrosis syndrome , usually seen in patients with end - stage renal disease and secondary hyperparathyroidism .
we report a 57-year - old polyneuropathy , organomegaly , endocrinopathy , monoclonal gammopathy , and skin changes ( poems ) syndrome patient complicated with extensive skin ulcers due to calciphylaxis .
he first noted a painful cutaneous ulcer on his left thigh , and then skin lesions rapidly worsened , resulting in multiple intractable ulcers with gangrene on his legs and trunk in a few months .
serum vascular endothelial growth factor ( vegf ) was markedly elevated .
biopsy samples from his skin ulcers showed the deposition of calcium in the medial layer of cutaneous vessels , this finding being compatible with calciphylaxis .
this is the second reported case with poems syndrome complicated with calciphylaxis .
both patients had no evidence of renal failure , hyperparathyroidism , or clotting disorders .
the pathogenic link between poems syndrome and calciphylaxis is still unclear , but vegf is known to regulate vascular calcification , in cooperation with bone morphogenetic proteins .
further , corticosteroid and several proinflammatory cytokines activate nuclear factor-b pathway , known as the final common pathway leading to vascular calcification . taken together
, we consider that poems syndrome can be an independent risk condition for calciphylaxis . |
<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:
: idiopathic normal pressure hydrocephalus ( inph ) is an adult - onset syndrome of uncertain origin involving nonobstructive enlargement of the cerebral ventricles in combination with one or more of the symptoms of gait disturbance , urinary dysfunction , and cognitive impairment1 ) . because of the treatable nature of inph , selection of patients potentially benefitting from cerebrospinal fluid ( csf ) shunt surgery is important .
the csf tap test ( csftt ) is a simple procedure proven to have a high positive predictive value when correlated to successful shunt surgery23 ) .
furthermore , many neurosurgical centers recommend using it as a key tool in the diagnosis of inph5 ) . however , despite its excellent track record in predicting successful shunt surgery , the test has a relatively low sensitivity in diagnosing inph14 ) .
most clinicians evaluate change in gait , a key component in the diagnosis of inph following the csftt only once , most often within 24 hours of the tap11,21 ) . from this point of view , we report an inph patient with delayed improvement after the csftt , following japanese standards5,6 ) . in general
, the japanese standards are considered popular and reasonable criteria in asia for evaluating response to the csftt5,6 ) .
we proceeded with shunt surgery in virtue of a second csftt with an extended evaluation period over several days revealing the patient as a responder .
a 68-year - old man presented to our hospital for evaluation of progressive impairment of gait , balance , and memory .
twenty months earlier , he had developed a short - stepped gait and impaired balance without urinary symptoms .
there was progressive deterioration in his gait , and he suffered a few falls recently .
his daughter described a 12-month gradual decline in his ability to express himself and , more recently , difficulties in carrying out complex tasks .
she reported that his short - term memory had been functionally impaired over the past few months .
he had accumulated a 40-pack - year smoking habit , but he had stopped smoking 5 years before presentation . his alcohol intake was restricted to social functions .
he did not have a history of stroke or other neurological , metabolic , or neoplastic disorders which might produce dementia symptoms , or parkinsonism , or a history of hospitalization for depression .
the patient 's cognitive function was impaired [ korean mini - mental state examination ( k - mmse ) score 23 out of 30 and clinical dementia rating scale 1 ] , and a frontal release sign ( palmomental reflex ) was present2,8 ) .
formal neuropsychological evaluation showed a deficit in visuospatial function ( copy of the rey - osterrieth complex figure ) and memory ( korean hopkins verbal learning test and recall and recognition of the rey - osterrieth complex figure ) with frontal dysfunctions ( frontal assessment battery ) .
all laboratory test results , including a blood - chemistry panel , complete blood count , thyroid function tests , measurement of vitamin b12 levels , and screening for inflammatory and infectious diseases such as neurosyphilis , were unremarkable .
brain magnetic resonance imaging revealed communicating hydrocephalus with an evans ' ratio of 0.354 ) , and also showed csf signal void in the cerebral aqueduct and enlargement of the temporal horns of the lateral ventricles ( fig .
1 ) . he showed no evidence of a related antecedent event , such as head trauma , intracerebral hemorrhage , meningitis , or another known cause of secondary hydrocephalus .
he was diagnosed as having inph following the consensus criteria of relkin et al.17 ) .
the following several psychological tests and walking tests were applied following the csftt . the inph grading scale ( inphgs )
is a clinician - rated scale for assessing the severity of each of the 3 disorders of inph ( cognitive impairment , gait disturbance and urinary disturbance)9 ) .
a five - point subscale was used to rate the severity of each fundamental symptom of inph after an interview with patients and caregivers .
the gait assessment included measurements of time and number of steps on the timed up and go test ( tug ) and the 10-m walking test15,19 ) .
these are valid tests of functional mobility used in many studies to evaluate walking ability15,19 ) .
both tests were separately performed four times , and the mean score was used . at first hospitalization , a lumbar tap with removal of 40 ml of csf was performed . before and after the tap
, he was evaluated using the inphgs , k - mmse , tug , and 10-m walking tests ( table 1 ) .
change in gait was evaluated 24 hours after the tap11,21 ) , while change in cognition and urination was evaluated at one week9 ) .
response to the csftt was evaluated using three major scales : inphgs , tug and k - mmse .
the following criteria were used to identify responders : improvement of one point or more on the inphgs , more than 10% improvement in time on tug , or more than 3 points improvement on the k - mmse .
he did not show sufficient improvement by these criteria , and was judged as a non - responder ( table 1 ) .
the subjective impression of the patient and his family members , as well as 2 experienced neurologists , regarding overall change in gait after the csftt was ' no improvement ' within 24 hours . however , his daughter reported that his gait appeared to improve 2 or 3 days after the tap , and again became progressively worse at one week when he visited our clinic for the follow - up cognition test . at that time , the patient and his family wanted conservative treatment with observation instead of operation . over the next 3 months , there was deterioration in his gait and balance again .
trials of levodopa , with dosage up to 600 mg / day , offered no benefit . he suffered multiple falls during the ensuing month .
he finally required assistance when walking on an uneven road . at the second hospitalization for the csftt , we examined his change in gait over seven days in more detail , considering the findings from the first hospitalization ( table 1 ) .
it was noticed that his gait began to improve 24 hours after tap and more so 48 hours after tap , and eventually he did show improvement by the criteria : more than 10% improvement in time on tug .
the patient and his family were repeatedly asked about their subjective impressions regarding overall improvement after the csftt .
the gait difficulties were almost fully resolved , and the balance problem disappeared after 1 month ( table 1 ) .
although the surgical procedure for inph is generally considered technically easy , there are risks of complications , both short term and long term10,20 ) .
thus , methods for dynamic measurements of csf circulation as well as various clinical tests have been used to predict the outcome of a shunt operation . in general , response to a csftt
is considered to be useful for predicting a favorable response to shunt surgery , particularly in inph patients . and
because it is easy and quite safe to perform in practice , the japanese guidelines for management of inph recommended the csftt as one of the most important diagnostic tests5 ) .
this test also has the advantage of being simple to perform without any specialized equipment .
therefore , the csftt is generally recommended as a key step in the diagnosis of inph . however , even in the two most frequently used guidelines for inph , there are no standard protocols for evaluation following the csftt5,17 ) .
thus , if evaluation is made at the wrong time , patients who would be indicated for surgery may be overlooked and considered as non - responders .
particularly , a challenge for the csftt is the high variability in the judgment of results ( responder or non - responder ) .
this might also explain the low sensitivity of the tap test ( ranging from 26% to 62%)14 ) .
our patient also did not show sufficient improvement by the aforementioned criteria 24 hours after the tap test , and was judged as a non - responder at the first hospitalization .
the japanese standards are generally considered popular and reasonable criteria for judgment of response to csftt in asia5,6 ) .
we think that the low sensitivity of the csftt is at least partly compensated for by repetitive testing over several days . as long as we do the tap test
if the patient shows delayed improvement after csftt , we must be more careful in the judgment of the results ( responder or non - responder ) . our inph patient with a favorable response to shunt surgery showed improvement by the criteria 48 hours after tap : more than 10% improvement in time on the tug test .
it was a delayed response to some degree , because in most previous studies involving the csftt , it is recommended that the change in gait can be evaluated only once within the first 24 hours11,21 ) .
in fact , most previous studies assessed the effect of the csftt on gait and mental impairment within eight hours after csf removal3,7,13,16,18,22,23 ) .
furthermore , we found delayed improvement after the csftt in our case because of repetitive testing over several days .
the subjective impression of patient and his family members , as well as clinicians , regarding overall change in gait after a csftt can also change with time . and considering learning effects , it was also important for us in our diagnosis between a responder and non - responder that our patient 's gait got worse at one week again .
it might be essential to evaluate the response of a tap test repetitively for at least several days .
in general , it was thought that the continuous external lumbar drainage ( eld ) might achieve a clinically more useful diagnostic sensitivity than the csftt because the former test drained a larger csf volume14 ) . however , another explanation for the higher sensitivity of eld could be the longer evaluation period allowing for more cautious analysis .
as the disease progresses and the ventricles get larger , they may lose elasticity12 ) .
if the ventricles are slightly shrunken by csf removal , the elasticity of the ventricles may recover along with symptomatic improvement over a certain period12 ) .
we suppose the recovery time might be variable depending on the individual differences or the state of illness .
this is an interesting report of an inph patient with a favorable response to shunt surgery who showed delayed improvement after the csftt , despite initially being classified as a non - responder .
repeated evaluation of change of gait over 7 days may increase the sensitivity in identifying csftt responders .
however , further studies developing the standard procedure of the csftt should be considered to establish this hypothesis . | ### Summary:
: the cerebrospinal fluid tap test ( csftt ) is recommended as a key step in the diagnosis of idiopathic normal pressure hydrocephalus ( inph ) . while there is no generally accepted evaluation period for ascertaining a csftt responder ,
a substantial number of patients are evaluated only once within 24 hours of the test for improvement in gait .
we report an inph patient with a favorable response to shunt surgery , who was first judged a non - responder by this standard , though subsequently was judged a responder in virtue of repetitively testing gait over 7 days . a 68-year - old man presented with progressive impairment of gait , balance , and memory .
he was diagnosed as inph with an evans ' ratio of 0.35 . at first hospitalization ,
change in gait was evaluated 24 hours after the csftt .
he did n't show any significant improvement and was judged as a non - responder .
however , at the second csftt , we repetitively tested his change in gait over seven days .
forty - eight hours after the tap , he showed significant improvement in his gait .
he was then confirmed as a responder .
after the operation , the gait difficulties were almost fully resolved .
further studies developing the standard procedure of the csftt should be considered . |
<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 jugular foramen is a bony canal in the posterior cranial fossa , located between the temporal and occipital bones at the posterior end of the petro - occipital fissure , above and lateral to the foramen magnum .
the upper border of the foramen contains an intrajugular process , which divides the foramen into a large posterolateral compartment , the sigmoid part , which contains the sigmoid sinus accompanied by a meningeal branch of the occipital artery ; and a small anteromedial compartment , the petrosal part , which contains the inferior petrosal sinus accompanied by a meningeal branch of the ascending pharyngeal artery .
the glossopharyngeal , vagus , and accessory nerves course between the petrosal part and sigmoid part , lying medial to the intrajugular process .
the jugular foramen has constantly fascinated ent , radiologists , and neurosurgeons because of modern advances in surgical procedures involving skull base and middle ear .
tumors in this area such as schwannoma , meningioma , glomus jugulare , and chordoma can produce multiple cranial nerve palsies , i.e. , jugular foramen syndrome ( vernet 's syndrome ) .
most of the approaches for resection for these tumors such as retrosigmoid , transjugular craniotomy require partial petrosectomy traversing the jugular fossa .
thus , the knowledge of anatomical details and dimensions of jugular foramen would be a great help to these surgeons while approaching this area .
various morphometric data of jugular foramen on indian population are available , but they were done from the exocranial aspect of skull base only , which is not a complete morphometry of jugular foramen .
due to the inadequate knowledge about complete morphometry of the jugular foramen in both sexes , this study was conducted to perform an in - depth morphometric analysis and report variations of jugular foramen .
the study was conducted on a sample of 114 adult human dry skulls ( 63 males and 51 females ) collected from the osteology museum in the department .
the dimensions of the jugular foramen measured with the help of a digital vernier calliper ( accuracy up to 0.01 mm ) in millimeters were as follows : ( a ) endocranial aspect of skull base ; maximum length ( l ) , maximum width of anteromedial ( amw ) and posterolateral ( plw * ) parts of jf , distance of posterior margin of jf from intrajugular process of temporal bone ( pmf - pij [ t ] ) , distance of posterior margin of jf from intrajugular process of occipital bone ( pmf - pij [ o ] ) , width of sigmoid sinus groove ( ssg ) .
x : maximum length ( ap * ) , y : maximum width ( mw ) , z : maximum depth of jugular fossa ( depth jf ) , b : maximum width of jugular fossa ( wjf * ) , a : distance of stylomastoid foramen from lateral margin of jugular foramen .
( * significant parameters )
maximum width along the long axis ( mw)maximum length perpendicular to the long axis ( ap)maximum depth of jugular fossa - if domed , measured from the summit of dome to lower border of jugular fossa ( depth jf)maximum width of jugular fossa - if domed ( wjf)distance of stylomastoid foramen from lateral margin of jugular foramen ( smjf ) .
maximum width along the long axis ( mw ) maximum length perpendicular to the long axis ( ap ) maximum depth of jugular fossa - if domed , measured from the summit of dome to lower border of jugular fossa ( depth jf ) maximum width of jugular fossa - if domed ( wjf ) distance of stylomastoid foramen from lateral margin of jugular foramen ( smjf ) .
maximum length along the long axis ( l)maximum width of anteromedial ( amw ) and posterolateral ( plw ) parts of jugular foramendistance between the posterior margin of the jugular foramen ( pmf ) and the peak of the intrajugular process ( pij ) of the temporal bone ( pmf - pij [ t])distance between the posterior margin of the jugular foramen ( pmf ) and the peak of the intrajugular process of the occipital bone ( pmf - pij [ o])width of the sigmoid sinus groove ( ssg ) at the level of the posterior margin of the jugular foramen .
maximum length along the long axis ( l ) maximum width of anteromedial ( amw ) and posterolateral ( plw ) parts of jugular foramen distance between the posterior margin of the jugular foramen ( pmf ) and the peak of the intrajugular process ( pij ) of the temporal bone ( pmf - pij [ t ] ) distance between the posterior margin of the jugular foramen ( pmf ) and the peak of the intrajugular process of the occipital bone ( pmf - pij [ o ] ) width of the sigmoid sinus groove ( ssg ) at the level of the posterior margin of the jugular foramen .
all the measurements were taken bilaterally , and photography was done using kodak m1063 digital camera .
statistical analysis was performed using chi - square test for nominal categorical data and student 's t - test for normally distributed continuous variables in ibm spss statistics for windows version 23.0 , usa to assess the relationship between the examined variables . a level of significance of p < 0.05 was used .
( a ) endocranial aspect of skull base ; maximum length ( l ) , maximum width of anteromedial ( amw ) and posterolateral ( plw * ) parts of jf , distance of posterior margin of jf from intrajugular process of temporal bone ( pmf - pij [ t ] ) , distance of posterior margin of jf from intrajugular process of occipital bone ( pmf - pij [ o ] ) , width of sigmoid sinus groove ( ssg ) .
x : maximum length ( ap * ) , y : maximum width ( mw ) , z : maximum depth of jugular fossa ( depth jf ) , b : maximum width of jugular fossa ( wjf * ) , a : distance of stylomastoid foramen from lateral margin of jugular foramen .
( * significant parameters )
maximum width along the long axis ( mw)maximum length perpendicular to the long axis ( ap)maximum depth of jugular fossa - if domed , measured from the summit of dome to lower border of jugular fossa ( depth jf)maximum width of jugular fossa - if domed ( wjf)distance of stylomastoid foramen from lateral margin of jugular foramen ( smjf ) .
maximum width along the long axis ( mw ) maximum length perpendicular to the long axis ( ap ) maximum depth of jugular fossa - if domed , measured from the summit of dome to lower border of jugular fossa ( depth jf ) maximum width of jugular fossa - if domed ( wjf ) distance of stylomastoid foramen from lateral margin of jugular foramen ( smjf ) .
maximum length along the long axis ( l)maximum width of anteromedial ( amw ) and posterolateral ( plw ) parts of jugular foramendistance between the posterior margin of the jugular foramen ( pmf ) and the peak of the intrajugular process ( pij ) of the temporal bone ( pmf - pij [ t])distance between the posterior margin of the jugular foramen ( pmf ) and the peak of the intrajugular process of the occipital bone ( pmf - pij [ o])width of the sigmoid sinus groove ( ssg ) at the level of the posterior margin of the jugular foramen .
maximum length along the long axis ( l ) maximum width of anteromedial ( amw ) and posterolateral ( plw ) parts of jugular foramen distance between the posterior margin of the jugular foramen ( pmf ) and the peak of the intrajugular process ( pij ) of the temporal bone ( pmf - pij [ t ] ) distance between the posterior margin of the jugular foramen ( pmf ) and the peak of the intrajugular process of the occipital bone ( pmf - pij [ o ] ) width of the sigmoid sinus groove ( ssg ) at the level of the posterior margin of the jugular foramen .
all the measurements were taken bilaterally , and photography was done using kodak m1063 digital camera .
statistical analysis was performed using chi - square test for nominal categorical data and student 's t - test for normally distributed continuous variables in ibm spss statistics for windows version 23.0 , usa to assess the relationship between the examined variables .
all the parameters of the endocranial aspect of right jugular foramen were greater than the left side but were not significant except the maximum width of the posterolateral ( plw ) part of jugular foramen which was significant ( p < 0.05 ) . furthermore , the parameters of exocranial aspect of right jugular foramen were greater than the left side except the distance of stylomastoid foramen from lateral margin of jugular foramen ( smjf ) which was greater on the left side .
these exocranial parameters were not significant except the maximum length perpendicular to the long axis ( ap ) and maximum width of jugular fossa if domed ( wjf ) which were significant . various morphometric measurements of jugular foramen of total 114 dry adult human skulls gender differences in morphometric measurements of jugular foramen incidence of presence of dome of jugular fossa gender differences between various measurements of jugular foramen were reported [ table 2 ] .
all measurements were greater in males as compared to females except maximum length along the long axis ( l ) , distance between the posterior margin of the jugular foramen and the peak of the intrajugular process of the temporal bone ( pmf - pij [ t ] ) , and distance between the posterior margin of the jugular foramen and the peak of the intrajugular process of the occipital bone ( pmf - pij [ o ] ) on both sides , in which females had greater values .
the gender differences between l , pmf - pij ( t ) on left side , and ap on the exocranial aspect of right jugular foramen was statistically significant . a significant difference was noted between the presence of dome in the right jugular fossa ( 96.83% in males and 96.08% in females ; total 96.49% ) as compared to the left jugular fossa ( 84.13% in males and 90.2% in females ; total 86.84% ) [ figure 2 ] .
bilateral dome of jugular fossa was present in 62.3% ( 60.32% in males and 64.71% in females ) of cases .
inferior view of skull base showing : ( a ) absent dome of left jugular fossa * ; ( b ) absent dome of right jugular fossa .
cc : carotid canal , mp : mastoid process , sp : styloid process , oc : occipital condyle .
( * significant parameter ) in our study , we observed complete left bipartite compartmentalization in 8 cases ( 5 in males and 3 in females ; total 7% ) , incomplete right and left bipartite compartmentalization in 4 ( 3 in males and 1 in females ; total 3.5% ) and 13 ( 7 in males and 6 in females ; total 11.4% ) cases , respectively .
we also noticed 3 cases ( 2 in males and 1 in females ; total 2.6% ) of bilateral incomplete bipartite compartmentalization [ table 4 and figure 3 ] .
comparison of septation of jugular foramen with previous studies inferior view of skull base showing : ( a ) incomplete septation of bilateral jugular foramen , ( b ) complete septation of left jugular foramen , ( c ) incomplete septation of right jugular foramen , ( d ) incomplete septation of left jugular foramen
the diverse anatomy of the jugular foramen , the relationships of the neurovascular structures which pass through it , the variations in its size and shape , as well as surgical approaches to this key part of the skull base , attracts the minds of many neurosurgeons and radiologists .
standard anatomical textbook states that the superior sagittal sinus drains into the right transverse sinus , thus the right jugular foramen is expected to be larger than the left .
the size and shape of the jugular foramen are also related to the size of the internal jugular vein and the presence of superior jugular bulb .
the differences in the size of the right and left internal jugular veins are evident in the human embryo at the 23 mm stage ( 8 weeks postconception ) and most likely results from the difference in the outline of the development of the right and left brachiocephalic veins .
many authors have also reported larger diameters of the right jugular foramen as compared to the left on both endo- and exocranial aspects in various ethnic groups [ table 5 ] .
comparison of various morphometric parameters of jugular foramen with other osteological studies our findings also supported and were very nearer to these previous works .
thus , the chances of compression of neurovascular structures passing through jugular foramen may be more common on the left side and also approach to the tumors in this area may be more difficult as all the diameters of left - sided jugular foramen are lesser .
kotgirwar and athavale reported a significant difference between the mean right ( 9.38 mm ) and left ( 7.16 mm ) mw diameter on the exocranial aspect in the south indian population , but the present study did not find any significant difference in the mw diameter .
they also reported mean ap diameter to be 15.21 mm and 13.74 mm on the right and left side , respectively ( exocranial aspect ) , in south indian population suggesting an oval shape of the jugular foramen with its long axis along the anteroposterior diameter .
in contrast , our study reported mean ap diameter to be 9.37 mm and 6.88 mm and mw diameter to be 13.72 mm and 13.07 mm on the right and left side , respectively , suggesting an oval shape of the jugular foramen with its long axis along the mediolateral diameter .
this finding in our study was also similar to other studies done in other populations .
this difference between the long axes of the jugular foramen could be due to different origin of the south indian population , i.e. dravidians as compared to the whole adult indian population which is a mixture of aryans and dravidians origin .
found statistically significant difference between mean right ( 9.32 mm ) and left ( 7.34 mm ) ap diameter and mean right ( 8.99 mm ) and left ( 7.54 mm ) wjf distance on the exocranial aspect .
these diameters indicate the size of jugular bulb and its variability reflects the variable development of superior jugular bulb .
vlajkovic et al . reported statistically significant difference between mean right ( 7.11 mm ) and left ( 5.86 mm ) pmf - pij ( t ) and mean right ( 7.78 mm ) and left ( 6.42 mm ) plw distance on the endocranial aspect .
however , our study reported only statistically significant difference only in the mean right ( 7.78 mm ) and left ( 6.42 mm ) plw distance on the endocranial aspect .
the greater mean width of the groove for the sigmoid sinus ( ssg ) at the level of the posterior margin of the right jugular foramen ( 8.16 mm ) as compared to left ( 7.15 mm ) obtained in our study evidently indicates a larger caliber of the right sigmoid sinus .
this is comparable to other studies and is interpreted as a larger superior sagittal sinus draining into the right transverse sinus and then through the right sigmoid sinus into the right internal jugular vein , which leads to a larger right jugular foramen .
females had greater maximum length along the long axis ( l ) , distance between the posterior margin of the jugular foramen and the peak of the intrajugular process of the temporal bone ( pmf - pij [ t ] ) , and distance between the posterior margin of the jugular foramen and the peak of the intrajugular process of the occipital bone ( pmf - pij [ o ] ) .
the significant sexual difference in maximum length along the long axis ( l ) as reported in this study indicated that the jugular foramen on the endocranial aspect in females was more long oval shaped than males on both the sides . in females , statistically significant greater measurements of pmf - pij ( t ) on the left side than males were also found .
this suggests that the posterolateral compartment in females has a greater length along its anterior boundary of left jugular foramen . in males ,
the maximum length perpendicular to the long axis ( ap ) on exocranial aspect of right jugular foramen was statistically greater as compared to females .
this suggests that the right jugular foramen along exocranial aspect has a larger area in males than females .
alternatively , we can say that right jugular foramen in females is smaller in area which may be a risk factor for compression of neurovascular structures passing through the jugular foramen in cases of tumors invading this region .
overall , these gender differences in the measurements of jugular foramen can not be overlooked as slightest error in measurements in neurosurgeries in this region can be detrimental .
this gender data in the present study could not be compared as these sexual differences were not reported earlier in previous studies .
furthermore , in our study , domed jugular fossa was present in 96.49% ( 96.83% in males and 96.08% in females ) of cases on the right and in 86.84% ( 84.13% in males and 90.2% in females ) of cases on the left side , which indicates the existence of well - expressed superior jugular bulb of internal jugular vein ( statistically significant more on the right side ) .
no statistically significant gender differences were reported in the presence of dome of jugular fossa .
bilateral dome of jugular fossa was present in 62.3% ( 60.32% in males and 64.71% in females ) of cases which is approximately equal to the finding by singla et al .
thus , in total , 8.44% of the jugular fossa showed the absence of dome bony roof .
kotgirwar and athavale reported a higher incidence ( 20% ) of absence of roof of jugular fossa .
no bilateral absence of domed jugular fossa was observed in our study which was in contrast to other previous studies which found 9.6%25.2% bilateral absence of dome of jugular fossa .
the jugular fossa along with superior jugular bulb forms the floor of middle ear cavity .
many cases of glomus jugulare tumors eroding this floor and penetrating into the middle ear cavity have been reported .
the absence of domed bony roof indicates that the superior jugular bulb is poorly developed or absent in such cases and may not form the floor of middle ear cavity .
thus , there is less risk of penetration of these tumors into the middle ear in these cases .
the mean depth of right jugular fossa ( 12.54 mm ) was higher as compared to the left ( 8.72 mm ) .
males demonstrated a greater depth of jugular fossa as compared to females ( statistically nonsignificant ) .
a higher jugular fossa may cause conductive hearing loss because of its contact with the tympanic membrane , thus affecting ossicular chain integrity .
higher jugular fossa is a risk factor during surgery for vestibular schwannomas as it lies very close to the internal acoustic meatus .
these include infratemporal , transcondylar , suboccipital , transsigmoid , and extreme lateral approaches . among these approaches , infratemporal is the more popular but requires rerouting of the facial nerve . as the facial nerve emerges from the stylomastoid foramen , the distance of facial nerve from jugular foramen from the distance of stylomastoid foramen to the lateral margin of jugular foramen ( smjf ) can serve as a guide for neurosurgeons , during the procedure of rerouting of facial nerve .
our study shows that the facial nerve lies at a mean distance of 4.76 mm and 5.13 mm from the lateral margins of right and left jugular foramen , respectively .
this side difference in the distance of facial nerve from jugular foramen was statistically nonsignificant .
these dimensions are comparable to the earlier study by kotgirwar and athavale overall , males showed greater length of smjf than females but were also not statistically significant . in our study , we observed complete left bipartite compartmentalization in 8 cases ( 5 in males and 3 in females ; total 7% ) , incomplete right and left bipartite compartmentalization in 4 ( 3 in males and 1 in females ; total 3.5% ) and 13 ( 7 in males and 6 in females ; total 11.4% ) cases , respectively .
these data were comparatively less than the earlier studies done on other ethnic population [ table 4 ] .
three cases ( 2 in males and 1 in females ; total 2.6% ) of bilateral incomplete bipartite compartmentalization were also noticed which has not been reported in previous studies .
these bridging or compartmentalization patterns can compress the structures passing through the jugular foramen , thereby mimicking the clinical presentations of glomus jugulare tumor ; it can produce multiple cranial nerve palsies , i.e. , jugular foramen syndrome ( vernet 's syndrome ) .
furthermore , by looking at the above - mentioned data , it is clear that bridging is more common in males than females .
the present study concludes that there is a significant gender difference between the size of jugular foramen of the right and left side .
the morphometric data and variations observed in the present study are of enormous value to neurosurgeons and ent surgeons while performing middle ear surgeries for various jugular foramen tumors .
furthermore , the variable compartmentalization patterns in both sexes can cause compression of the structures passing through this foramen , hence mimicking the clinical presentations of glomus jugulare tumor .
| ### Summary:
: introduction : tumors affecting structures in the vicinity of jugular foramen such as glomus jugulare require microsurgical approach to access this region .
these tumors tend to alter the normal architecture of the jugular foramen by invading it .
therefore , it is not feasible to have correct anatomic visualization of the foramen in the presence of such pathologies . hence , a comprehensive knowledge of the jugular foramen is needed by all the neurosurgeons while doing surgery in this region.aim:due to the inadequate knowledge of the accurate morphology of the jugular foramen in different sexes , the aim of this osteological study was to provide a complete morphometry including gender differences and describe some morphological characteristics of the jugular foramen in an adult indian population.materials and methods : the study was done on 114 adult human dry skulls ( 63 males and 51 females ) collected from the osteology museum in the department .
various dimensions of both endo- and exocranial aspect of jugular foramen were measured .
presence and absence of domed bony roof of jugular fossa and compartmentalization of jugular foramen were also noticed .
statistical analysis was done using chi - square test and student 's t - test in spss version 23.results:all the parameters of right jugular foramen were greater than the left side , except the distance of stylomastoid foramen from lateral margin of jugular foramen ( smjf ) which was greater on the left side .
gender differences between various measurements of jugular foramen , presence of dome of jugular fossa , and compartmentalization patterns were reported.conclusion:this study gives knowledge about the various parameters , anatomical variations of jugular foramen in both sexes of an adult indian population , and its clinical impact on the surgeries of this region . |
<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:
: trigeminal neuralgia ( tn ) is a paroxysmal shock - like pain restricted to the innervation area of one or more trigeminal branches , often set off by light stimuli in a trigger zone.1,2 it is idiopathic , and imaging exams ( computed tomography and/or magnetic resonance ) are necessary to exclude intracranial expansive lesions , which are present in 5% of cases.3 tn causes severe compromise of the oral hygiene , habitual tasks and quality of life , and the patients often get depressed and desperate.1,4 in studies in usa,5 italy6 and france,7 155 habitants in each 1.000.000 are affected .
general characteristcs are similar among countries and include a mean of age around 60 years old , being more often in the female gender , right side , maxillary and/or mandibular trigeminal branches , in opposite to post - herpetic neuralgia , more common at the ophthalmic branch .
tn is the first symptom of multiple sclerosis in 14% , and it affects 510% of multiple sclerosis patients.1 in these cases , it is usually bilateral .
patients are often referred to neurosurgery because of clinical treatment failure , and the duration of the disease usually influences that . on the other side ,
other diseases are common in the elderly and can cause complications during and after the surgery.2 thus , the objective of this study was to investigate the clinical characteristics of patients with trigeminal neuralgia referred to neurosurgery in a center of reference .
this study was based on the retrospective evaluation of 395 patients with trigeminal neuralgia referred to neurosurgical treatment at a general hospital , which is a center of reference for this kind of treatment for all parts of the country .
the patients included in this study corresponded to all that were indicated for percutaneous procedures , including balloon compression of the trigeminal ganglion and radiofrequency rhizotomy .
all of them underwent an evaluation of postoperative complications.8,9 all patients signed the informed consent and the protocol was approved by the ethics committee of the hospital .
they were referred to neurosurgery because of failure of the pharmacological treatment with anticonvulsants or because of collateral effects including allergy , hepatic disease and decrease in the number of leukocytes in blood count .
patients were diagnosed according to the definition on the criteria of the international association for the study of pain ( iasp).10 these criteria were the edition for unification of pain diagnosis ; for trigeminal neuralgia , it was based on the definition from 1776 of john fothergill .
the first 290 patients were evaluated between april , 1979 and june , 1984 , and the last 105 patients were evaluated between june , 2003 and may , 2004 .
complementary investigation consisted of skull radiography and cranial tomography in all patients , which were normal in this sample .
patients were evaluated considering their general characteristics , including gender , ages , color or race , and trigeminal neuralgia characteristics ( side and branch affected ) .
associated diseases and other findings , including neurological abnormalities were also investigated , and data were crossed to verify possible correlations among the variables and between samples .
the instrument used was the edof - hc protocol ( orofacial pain clinic hospital das clinicas ) , a standardized orofacial pain questionnaire to detail : 1 ) chief complaint , 2 ) general pain characteristics ( location , quality , duration , pain relief or pain triggering ) , 3 ) presence of headache and/or body pain , and 4 ) patient s medical history and co - morbidities.2 data were analyzed in their frequencies , means and standard deviations , and the intervals of confidence and proportions .
the chi - square test was used to compare data between the samples and the level of significance was of 5% .
data were analyzed in their frequencies , means and standard deviations , and the intervals of confidence and proportions .
the chi - square test was used to compare data between the samples and the level of significance was of 5% .
from 290 tn patients , 166 ( 57.3% ) were female and 124 ( 42.7% ) were male , which was statistically significant when compared to the other sample from 2004 ( p<.05 ) ; 277 ( 95.5% ) of patients were white , 7 ( 2.4% ) yellow and 6 ( 2.1% ) black .
three ( 1.0% ) patients had family history of tn and 3.4% patients had previous history of surgical treatment for tn , but because of pain recurrence were referred again to surgery .
ages ranged from 17 to 88 years old , with a mean of 62.5 years old .
the association of the maxillary and the mandibular branch ( v2+v3 ) was the most frequent ( 28.0% ) , followed by the association of the ophthalmic and the maxillary branch ( v1+v2 ) ( 19.9% ) and only v3 ( 18.9% ) .
systemic diseases were observed in 235 ( 81.0% ) patients ( table 1 ) , and among them , heart diseases were the most common ( 71.8% ) .
the prevalence of hypertension was higher in the sample from 1984 when compared to the other one ( p<.05 ) .
corneal reflex asymmetry was present in 6.8% of patients , and facial hypoesthesia in 29.6% . from these cases , 4.7% of the patients with facial hypoesthesia and 12.8% of patients with corneal reflex asymmetry had no previous history of surgery at the face or for tn .
on the other hand , 3.4% of patients had facial nerve deficit and 2.2% trigeminal motor abnormalities , and all of these patients had had previous surgical treatment for tn .
other neurological findings were parkinson s disease in 3 patients , essential tremor in 3 , previous vascular cerebral accident in 2 , concomitant glossopharyngeal neuralgia tn in 2 , vertebral - basilar malformation in 1 and previous parietal meningoma in 1 . facial spasm was observed in 8 ( 2.8% ) patients .
it was ipsilateral in 4 ( 50.0% ) of them , and more frequent in patients with bilateral neuralgia ( 11.8% of cases ) when compared to unilateral neuralgia ( 2.2% of cases ) ( p<.05 ) .
only three patients had initial failure with the balloon compression , and they were re - operated .
they had no comorbidity associated and the trigeminal branches affected were v3 in 2 patients and v2 - 3 in one .
all of them had the right side affected . from 105 tn patients , 60 ( 57.1% ) were female and 45 ( 42.9% ) were male , which was statistically significant ( p<.05 ) ; 79 ( 75.2% ) patients were white , 23 ( 21.9% ) black and 3 ( 2.9% ) yellow .
ages ranged from 35 to 85 years old , with a mean of 60.8 years old ( figure 1 ) .
tn was more often at the right side ( 73 patients 69.5% ) ( p<.05 ) .
the mandibular ( v3 ) ( 29.5% ) and the maxillary ( v2 ) ( 29.5% ) branches isolated were the most affected , followed by the association between both ( 20.5% ) .
these patients had more often an isolated trigeminal branch affected when compared to the first sample ( p<.001 ) .
they had lower frequency of heart diseases ( 41.8% ) than the other group of patients ( p<.05 ) .
corneal reflex asymmetry was higher in this group and occurred in 20.1% ; facial hypoesthesia occurred in 27.3% , which was similar to the other group ; 9.9% of the patients with hypoesthesia and 13.6% of the patients with corneal reflex asymmetry had no previous history of surgery at the face or for tn .
all patients with multiple sclerosis had unilateral tn . despite these differences between both samples about branch affected and prevalence of systemic diseases
the general characteristics as gender and ages were similar , and the neurological abnormalities were not associated to any other finding , as side affected , trigeminal branch or co - morbidity .
all patients in this sample were operated with the balloon compression of the trigeminal ganglion .
only one patient had initial failure with the balloon compression , and was re - operated .
he had no co - morbidity associated and his tn was at v3 , at the right side .
from 290 tn patients , 166 ( 57.3% ) were female and 124 ( 42.7% ) were male , which was statistically significant when compared to the other sample from 2004 ( p<.05 ) ; 277 ( 95.5% ) of patients were white , 7 ( 2.4% ) yellow and 6 ( 2.1% ) black .
three ( 1.0% ) patients had family history of tn and 3.4% patients had previous history of surgical treatment for tn , but because of pain recurrence were referred again to surgery .
ages ranged from 17 to 88 years old , with a mean of 62.5 years old .
the association of the maxillary and the mandibular branch ( v2+v3 ) was the most frequent ( 28.0% ) , followed by the association of the ophthalmic and the maxillary branch ( v1+v2 ) ( 19.9% ) and only v3 ( 18.9% ) .
systemic diseases were observed in 235 ( 81.0% ) patients ( table 1 ) , and among them , heart diseases were the most common ( 71.8% ) .
the prevalence of hypertension was higher in the sample from 1984 when compared to the other one ( p<.05 ) .
corneal reflex asymmetry was present in 6.8% of patients , and facial hypoesthesia in 29.6% . from these cases , 4.7% of the patients with facial hypoesthesia and 12.8% of patients with corneal reflex asymmetry had no previous history of surgery at the face or for tn .
on the other hand , 3.4% of patients had facial nerve deficit and 2.2% trigeminal motor abnormalities , and all of these patients had had previous surgical treatment for tn .
other neurological findings were parkinson s disease in 3 patients , essential tremor in 3 , previous vascular cerebral accident in 2 , concomitant glossopharyngeal neuralgia tn in 2 , vertebral - basilar malformation in 1 and previous parietal meningoma in 1 . facial spasm was observed in 8 ( 2.8% ) patients .
it was ipsilateral in 4 ( 50.0% ) of them , and more frequent in patients with bilateral neuralgia ( 11.8% of cases ) when compared to unilateral neuralgia ( 2.2% of cases ) ( p<.05 ) .
only three patients had initial failure with the balloon compression , and they were re - operated .
they had no comorbidity associated and the trigeminal branches affected were v3 in 2 patients and v2 - 3 in one .
from 105 tn patients , 60 ( 57.1% ) were female and 45 ( 42.9% ) were male , which was statistically significant ( p<.05 ) ; 79 ( 75.2% ) patients were white , 23 ( 21.9% ) black and 3 ( 2.9% ) yellow .
ages ranged from 35 to 85 years old , with a mean of 60.8 years old ( figure 1 ) .
tn was more often at the right side ( 73 patients 69.5% ) ( p<.05 ) .
the mandibular ( v3 ) ( 29.5% ) and the maxillary ( v2 ) ( 29.5% ) branches isolated were the most affected , followed by the association between both ( 20.5% ) .
these patients had more often an isolated trigeminal branch affected when compared to the first sample ( p<.001 ) .
they had lower frequency of heart diseases ( 41.8% ) than the other group of patients ( p<.05 ) .
corneal reflex asymmetry was higher in this group and occurred in 20.1% ; facial hypoesthesia occurred in 27.3% , which was similar to the other group ; 9.9% of the patients with hypoesthesia and 13.6% of the patients with corneal reflex asymmetry had no previous history of surgery at the face or for tn .
all patients with multiple sclerosis had unilateral tn . despite these differences between both samples about branch affected and prevalence of systemic diseases
the general characteristics as gender and ages were similar , and the neurological abnormalities were not associated to any other finding , as side affected , trigeminal branch or co - morbidity .
all patients in this sample were operated with the balloon compression of the trigeminal ganglion .
only one patient had initial failure with the balloon compression , and was re - operated .
he had no co - morbidity associated and his tn was at v3 , at the right side .
tn is a rare excruciating disease with long - term treatment and frequent neurosurgical indication .
this study determined the general characteristics of 395 tn patients in a brazilian population from two samples ( 1984 and 2004 ) .
its prevalence , epidemiology and general characteristics were similar to other countries.1,46 tn is more frequent in female patients , which can be due to a longer life expectation of women , and tn is more common in the elderly.11 rarely familiar cases are reported,12 and it happened in 1.0% of the patients at 1984 and in 2.9% at 2004 .
there are no studies that determined ethnical differences before , and although in this sample there was a higher prevalence of white patients , this issue should be investigated with samples from different parts of the world .
the right side was more affected than the left , and v2 and/or v3 were the most affected branches , which corresponds to other studies and is opposite to post - herpetic neuralgia.13 it is interesting that the first group of patients had more trigeminal branches association than the second group ( p<.001 ) .
the reason for it is unknown , but the affection of adjacent branches as long as the disease progresses until the referral for surgery might be an explanation.11 patients at the second sample were only referred to surgery after complete failure of pharmacological treatment , and thus the disease progressed affecting more branches . due to neurosurgical complications , neurosurgery was usually delayed and only indicated when there was complete failure of pharmacological treatment , but with the new non invasive techniques after the 80s , it started to be performed earlier.12 neurological findings ( abnormalities of the corneal reflex , facial spasm and facial hypoesthesia ) were present also in patients with no previous history of surgery , which corresponded to other studies that found discrete sensorial abnormalities in tn.14,15 trigeminal central sensitization occurs in any chronic pain , and sensorial abnormalities can happen . in these samples , they were not associated to any other findings of general characteristics , co - morbidities , surgical modality or other post - operative complications , which probably means that they are random , but future studies should investigate it to confirm that .
the neurological findings are not implicated in the referral for surgery and thus not biases in this study.7 hypertension and cardiac diseases were frequent in these samples and higher in the first group of patients ( p<.05 ) .
although this rate is slightly higher than the expected for the brazilian general population at the same ages of our study,16 it is possible that the difference is due to imperfect medical records at that evaluation time .
it is important to remind that intense pain can cause neurovegetative abnormalities and blood pressure increase can happen due to that when patients are in crises , and patients that already have hypertension can have severe complications due to that . on the other hand , the crises could occur more frequently in higher blood pressure episodes because of the vascular compression etiology of tn . the relevance this fact is controversial , and some authors have reported that it could be a coincidence in these patients.17 tn is very excruciating and is considered one of the worst pains , with subtle and intense crises , and cardiac compromise could happen after a long period of suffering.2 this is important because these patients should be monitored and supports the early indication of surgery when it is necessary to prevent these complications ; there are many studies in the literature focused on that.1822 the differences of prevalence of depression and migraine in table 1 are small and can be due to the imperfect data collection in the first sample , at the medical records . in this study , 2 different samples of well documented patients with tn were evaluated in order to investigate their clinical characteristics .
they correspond to two distinct periods of data collection . the option of maintenance of their data separated was not as comparison but because of the interval of time between them .
therefore , when analyzing the data , there were differences in the prevalence of systemic diseases and trigeminal branch affected , and that was the reason we opted in tabling it
. this might be a limitation of the study , but as we could observe both samples of patients with trigeminal neuralgia are homogeneous and similar in their characteristics .
other postoperative complications that did not differ between them can be observed in our previous publications.9,11
the general characteristics were similar than other studies about gender , ages , branch and side affected .
hypertension and cardiac diseases were also frequent and make the monitoring of the patients during crises necessary . | ### Summary:
: objectivesto investigate the clinical characteristics of patients with trigeminal neuralgia referred to surgery in a center of reference.methodswe evaluated the general characteristics of 395 patients with trigeminal neuralgia referred to neurosurgery as treatment .
they corresponded to 2 samples of 1984 and 2004 .
the edof - hc protocol ( orofacial pain questionnaire ) and the medical profile were used.resultsin the first study ( 1984 ) , with 290 patients , the higher prevalence was : women ( 57.3% ) , white ( 95.5% ) , with mean age of 62.5 .
the most affected trigeminal branches were the maxillary and/or mandibular branches ( 65.5% ) , and the right side was the most affected ( 57.6% ) .
from the second study ( 2004 ) , with 105 patients , 57.1% were women , 75.2% white , with a mean age of 60.8 .
the maxillary and/or mandibular branches ( 79.0% ) and the right side ( 69.5% ) were the most affected .
both samples had neurological abnormalities and systemic diseases ( mainly cardiovascular).conclusionsgeneral characteristics of these patients were similar to other samples of trigeminal neuralgia .
neurological findings were also present in patients with no previous surgical treatment for tn . hypertension and cardiac diseases were also frequent and make the monitoring of the patients during crises necessary . |
<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:
: worldwide , incidence rates of cutaneous malignant melanoma are rising in the last decades and only are exceeded by female pulmonary cancer .
the most evident risk factors for cutaneous malignant melanoma are environmental and lifestyles ( exposure to ultraviolet [ uv ] radiation and geographic localization ) together with individual factors ( number of nevus , dysplastic nevus , family history of melanoma , immunosuppression , inability to get a tan , hypersensitivity to sunlight , clear eyes , bland , and red hair ) .
regarding general population , the presence of two risk factors increases the risk of cutaneous malignant melanoma 24 times and the presence of three or more risk factors increases the risk 20 times .
recognized risk factors do not justify more than 40% of attributable risk in the population .
this calls to conduct further epidemiological studies and search for other risk factors such as hormones , lifestyles , alimentation , and occupation .
a classic strategy in search for new risk factors is to initiate investigation with ecological observational studies .
increased risk related to family history , genetic abnormalities affecting cdkn2a and cdk4 genes shared by other neoplasms , previous family associated neoplasms as retinoblastoma , li fraumeni syndrome , and lynch syndrome type ii recommends new research lines .
the presence of other noncutaneous neoplasms does not seem to increase the risk of melanoma ; however , it seems to be associated with the development of other hematological , brain , breast , uterine , and prostatic neoplasms .
the international agency for research on cancer ( iarc ) was established in 1965 by the world health assembly , as independently financed organization with the structure of the world health organization ( who ) .
cancer incidence in five continents is a publication edited periodically by iarc since 1966 in collaboration with the international association of cancer registries that includes information about cancer incidence in 5 years period .
information is obtained from cancer registries in different countries worldwide that satisfy basic quality requirements . before inclusion of the registries ,
although ecological studies have several limitations and bias , they are considered simple studies and frequently used to investigate new health problems and exposures .
these studies are exploratory and hypothesis generating , meanwhile experimental and analytical studies are considered confirmatory for these hypotheses .
advantages of these studies include availability of data and possibility to evaluate multiple levels of exposure in different geographic areas .
several authors such as susser suggest that ecological studies have several advantages because they investigate health problems in environmental context as the health of the population is more than pooling of individual patients .
the objective of the present study is to evaluate the geographic association between incidences of cutaneous malignant melanoma and 24 localizations of cancer in forty european countries in 2008 .
an ecological transversal study was conducted with the database of globocan project 2008 ( iarc ) .
our study included the registries of forty european countries : albania , austria , belgium , bosnia and herzegovina , bulgaria , byelorussia ( belarus ) , chez republic , croatia , cyprus , denmark , estonia , finland , france , germany , greece , hungary , iceland , ireland , island , italy , latvia , lithuania , luxemburg , macedonia , malta , moldavian republic , montenegro , norway , poland , portugal , romania , russia , serbia , slovenia , spain , sweden , switzerland , the netherlands , ukraine , and the united kingdom .
of the mentioned registries , we utilized incidence rates of age - adjusted and gender - stratified for the following localizations of cancer identified with their international classification of diseases-10 : brain and nervous system ( c70 - 72 ) , colon and rectum ( c18 - 21 ) , esophagus ( c15 ) , stomach ( c16 ) , liver and intrahepatic biliary system ( c22 ) , hodgkin lymphoma ( hl ) ( c81 ) , larynx ( c32 ) , leukemia ( c91 - 95 ) , cutaneous melanoma ( c43 ) , multiple myeloma ( c88 and c90 ) , nasopharynx ( c11 ) , non - hl ( nhl ) ( c82 - 85 , c96 ) , oral cavity ( c00 - 08 ) , pancreas ( c25 ) , prostate ( c61 ) , trachea , bronchial tree , lung ( c33 - 34 ) , kidney and ureter , testicles ( c62 ) , thyroid ( c73 ) , urinary bladder ( c67 ) , gall bladder and extrahepatic biliary system ( c23 - 24 ) , breast ( c50 ) , uterine cervix ( c53 ) , uterus ( c54 ) , and ovary ( c56 ) .
all statistical analyses were performed using the statistical package for social sciences version 15.0 ( spss inc . , headquarters , chicago , illinois , usa ) .
the mean incidence of cutaneous malignant melanoma in males of the included european countries was 7.9 4.6 per 100,000 habitants ( hbs ) , with maximum incidence rates in switzerland ( 18.1 per 100,000 ) , norway ( 17.9 per 100.000 ) , and sweden ( 16.1 per 100,000 ) .
minimum incidence rates were reported in cyprus ( 2.6 per 100,000 ) , greece ( 2.5 per 100,000 ) , and albania ( 2.2 per 100,000 )
. the mean incidence of cutaneous malignant melanoma in females of the included european countries was 8.4 5.4 per 100,000 hbs , with maximum incidence rates in denmark ( 21.9 per 100,000 ) , switzerland ( 20.5 per 100.000 ) , and the netherlands ( 39 per 100,000 ) .
minimum incidence rates were reported in albania ( 1.7 per 100,000 ) , greece ( 2.5 per 100,000 ) , and cyprus ( 16.1 per 100,000 ) . the maximum correlation between mean age / sex - adjusted incidence rates of cutaneous malignant melanoma in males
was shown with testicular cancer 5.4 ( 2.9 ) , cancer prostate 65 ( 31.4 ) , nhl 8.2 ( 3.2 ) , and myeloma 2.8 ( 1.2 ) . in females , the maximum correlation between mean age / sex - adjusted incidence rates of cutaneous malignant melanoma was shown with colorectal cancer 22.9 ( 5.6 ) , breast cancer 66 ( 20.6 ) , and nhl 5.8 ( 2.2 ) .
tables 1 and 2 show , in descending order , the highest twenty incidence rates of cancers correlated with cutaneous malignant melanoma . of every cancer
, we included countries with incidence rates over the mean incidence rate with 1 or 2 standard deviations .
males ' incidence rates per 100.000 adjusted by age and sex of 5 cancers in 20 european countries ( descending order ) females ' incidence rates per 100.000 adjusted by age and sex of 4 cancers in 20 european countries ( descending order ) analyzing incidence rates of cutaneous malignant melanoma in males , maximum correlation was found with testicular cancer ( r = 0.83 [ 95% confidence interval ( ci ) : 0.680.89 ] ) followed by myeloma ( r = 0.68 [ 95% ci : 0.460.81 ] ) , cancer prostate ( r = 0.66 [ 95% ci : 0.430.80 ] ) and nhl ( r = 0.63 [ 95% ci : 0.390.78 ] ) .
all these correlations were statistically significant with p < 0.05 . in females , cutaneous malignant melanoma had maximum correlations with breast cancer ( r = 0.80 [ 95% ci : 0.640.88 ] ) , colorectal cancer ( r = 0.72 [ 95% ci : 0.520.83 ] ) , and nhl ( r = 0.71 [ 95% ci : 0.500.83 ] ) .
currently , identification of cutaneous malignant melanoma risk factors is the most crucial problem in the epidemiology of the disease . the present study aims to evaluate the geographic association between cutaneous malignant melanoma and other 24 types of localizations of cancer .
potential limitations and objections of the methodology of our study should be considered before interpreting the results .
our results only belong to forty european countries and could not be generalized although the methodology can be applied in other continents .
another possible bias is the instability of calculated rates for a relatively rare disease such as cancer .
we tried to avoid these possible biases including only registration systems that fulfilled the quality criteria of the iarc and who .
the associations found could be attributed to the fact that some cancers are consequence or secondary to other type of cancer .
chemotherapy and/or radiotherapy could produce an iatrogenic effect and the presentation of second cancer because of improved life expectancies with modern treatments .
lens and newton - bishop conducted a systematic review about the association between cutaneous malignant melanoma and other types of cancer .
all reviewed studies included the risk of second cancer in the evolution of cutaneous malignant melanoma and nhl .
one of the possible causes of this association could be the exposure to uv rays , known risk factor for cutaneous malignant melanoma .
in addition , there is a clear interaction between exposure and inheritance , as well as cdkn2a gene .
this gene is quite frequent in australian and european patients with cutaneous malignant melanoma and usually associated with defects in mcir gene which codes hair color and susceptibility to sunburns .
in addition , uv radiations affect the immune response both systematically and locally in the skin .
uv - b ( 270320 nm ) radiation has the ability to impair the cutaneous immune system activity altering the antigen - presenting cells in the skin and reducing the hypersensitivity response as well as t - lymphocytes .
the selection of countries in this study has been based on the homogeneity in terms of geographical location together with the importance of phenotypes of nordic countries as a risk factor for cutaneous malignant melanoma .
a possible selection bias could be attributed to the nonrandom choice of countries to study .
our goal was not to include the european countries as representative of the population worldwide but rather extrapolate the results only for the studied population .
our results show associations between cutaneous malignant melanoma and other hormone - related cancers such as breast , testis , and prostate .
series of data were reported that make plausible relationship between estrogen and risk of cutaneous malignant melanoma , especially from the epidemiological point of view such as highest prevalence among females ( ratio men : women 1:1.8 ) , rise from menarche and decline after menopause , and higher survival in women .
the physiological plausibility includes changes in nevi melanocytic , chloasma , and increased pigmentation in other areas such as areolas , linea alba , and perineal skin during pregnancy , and hyperpigmentation of the face in 829% of oral contraceptives users .
moreover , in vitro studies shows that estradiol ( e2 ) favors proliferation of melanocytes and reduces tyrosinase activity and melanin content , presence of hormonal receptors for e2 ( estrogen receptor [ er ] ) in melanocytes and cutaneous malignant melanoma , and presence of er type in malignant and benign melanocytic lesions . to date , the presence of er in cutaneous malignant melanoma is a controversial issue although it has been demonstrated that there are subgroups of cutaneous malignant melanoma cells expressing it . in vitro studies of cutaneous malignant melanoma suggest that estrogens have effects on cell growth ; however , results are difficult to interpret because of insufficient knowledge about the effects of the stimulation of er- and its interaction with the activation of the er-. in case of endometrial carcinoma and breast cancer , the nucleic and nonnucleic effects of er have been demonstrated .
recently , it was reported that er- produces epigenetic alterations in cutaneous malignant melanoma through hypermethylation of the gene and consequently progression of the tumor .
epidemiology is another approach for formulating the question of whether there is a link between sex steroids and cutaneous malignant melanoma . till date , only a few epidemiological studies about this association deserve to be highlighted .
the largest prospective study of feskanich et al . included 183,693 women and 252 cutaneous malignant melanomas .
they carried out logistic regression analysis to control possible confounding factors such as skin type , hair color , number of nevus , family history family of melanoma , history of burns , body mass index , weight , and parity .
the authors concluded that premenopausal white women with > 10 years use of anovulatory anticonceptives had significantly higher risk of developing cutaneous malignant melanoma .
gefeller et al . conducted a meta - analysis pooling 18 case control studies to examine the same association , but they did not confirm the association between anticonceptives and the risk of cutaneous malignant melanoma . in concordance , karagas et al .
carried out an aggregated analysis of case studies and controls that comply with requirements such as controlled confusion biases , community - based population , and included at least 100 cases and controls . the ten studies that fulfilled these inclusion criteria confirmed that oral contraceptives use does not increase the risk of developing cutaneous malignant melanoma .
the correlation found between cutaneous melanoma and other malignancies of different embryonic origin raises hypothesis about its etiology .
our results call for further investigation of cutaneous melanoma etiology and possible risk factors ; future epidemiological studies should be conducted on large prospective cohorts to improve their internal validities .
| ### Summary:
: background : the presence of noncutaneous neoplasms does not seem to increase the risk of cutaneous malignant melanoma ; however , it seems to be associated with the development of other hematological , brain , breast , uterine , and prostatic neoplasms .
an ecological transversal study was conducted to study the geographic association between cutaneous malignant melanoma and 24 localizations of cancer in forty european countries.methods:cancer incidence rates were extracted from globocan database of the international agency for research on cancer .
we analyzed the age - adjusted and gender - stratified incidence rates for different localizations of cancer in forty european countries and calculated their correlation using pearson 's correlation test.results:in males , significant correlations were found between cutaneous malignant melanoma with testicular cancer ( r = 0.83 [ 95% confidence interval ( ci ) : 0.680.89 ] ) , myeloma ( r = 0.68 [ 95% ci : 0.460.81 ] ) , prostatic carcinoma ( r = 0.66 [ 95% ci : 0.430.80 ] ) , and non - hodgkin lymphoma ( nhl ) ( r = 0.63 [ 95% ci : 0.390.78 ] ) . in females
, significant correlations were found between cutaneous malignant melanoma with breast cancer ( r = 0.80 [ 95% ci : 0.640.88 ] ) , colorectal cancer ( r = 0.72 [ 95% ci : 0.520.83 ] ) , and nhl ( r = 0.71 [ 95% ci : 0.500.83]).conclusions : these correlations call to conduct new studies about the epidemiology of cancer in general and cutaneous malignant melanoma risk factors in particular . |
<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:
: of patients with advanced chronic obstructive pulmonary disease ( copd ) , approximately 94% report breathlessness and 40% report pain.1 in the palliative phases of copd , prevalence rates for breathlessness increase to 95%98% and for pain to 68%72%.2,3 while both of these symptoms are common in copd , only six studies have investigated these two symptoms in the same patients.16 pain has long been recognized as a symptom that includes a variety of sensations and multiple dimensions.7 breathlessness is described as a subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity .
8 only recently , though , was the multidimensional model of pain applied to the symptom of breathlessness.9 in that paper , lansing et al illustrated how breathlessness is a multidimensional construct , similar to pain , which consists of at least three separate and distinct qualities , namely
work is perceived as being uncomfortable when the work of breathing is increased by high ventilation , by increasing resistance to inspiration , weakness of respiratory muscles , or shortened inspiratory muscle length .
tightness appears to be associated with bronchoconstriction.9,10 taken together , in patients with copd , bronchoconstriction , airflow limitations , decreased ventilation , and hyperinflation may give rise to the sensations of air hunger , increased work of breathing and tightness.9,10 breathlessness and pain may share common neurophysiological pathways.9 recent evidence suggests that the anterior insula is a critical structure involved in the perception of the emotional aspects of breathlessness and pain . within this paradigm , pain is viewed as a part of the arousal / stress system that is characterized by increased sympathetic activation , which results in an increased respiratory rate.9 in a recent study of patients with fibromyalgia,11 patients who were taught slow breathing reported decreases in pain intensity.11 of note , the use of slow breathing had a greater effect on moderate pain than on mild pain.11 this finding suggests that breathing rate influences pain intensity.9,11 while information on the relationship between pain intensity and breathlessness is increasing , little is known about the relationships between these two symptoms in patients with copd . in one study that evaluated a number of respiratory parameters and pain in patients with copd,5 increases in self - reported breathlessness
were associated with increases in pain ( r = 0.22 , p < 0.05 ) .
in addition , decreases in oxygen saturation were associated with increased pain ( r = 0.23 , p < 0.05).5 in a more recent study,6 while no associations were found between objective measures of lung function and pain intensity , increased breathlessness was associated with increased pain intensity ( r = 0.26 , p < 0.01 ) . given the paucity of research on the associations between pain and breathlessness in patients with copd ,
the purposes of this study were to evaluate for differences in subjective ( ie , breathlessness ) and objective ( ie , lung function ) respiratory parameters between copd patients who did and did not have pain , and to evaluate which subjective and objective respiratory variables provided unique contributions to explain the likelihood of being classified in the pain group at the time of enrollment into a pulmonary rehabilitation program .
this cross - sectional study enrolled 136 patients with copd who were recruited between august 2005 and august 2007 prior to enrollment in a pulmonary rehabilitation program .
patients were included if they were : > 35 years of age ; diagnosed with copd by a pulmonary physician ; reported symptoms of breathlessness , chronic cough , and sputum production ; had a fev1/fvc < 70% and fev1 < 80% predicted ; and were able to read and write norwegian .
the exclusion criteria for the study were using long - term oxygen treatment and unstable heart disease .
patients were approached in the outpatient clinic and were given verbal and written information about the study .
in addition , all patients were asked to complete a number of self - report questionnaires and to return them in a postage paid envelope .
after 2 weeks , a reminder letter was sent to those who had not returned the questionnaires .
the study was approved by the hospital unit , the regional committee for medical research ethics , and the norwegian social science data services .
this cross - sectional study enrolled 136 patients with copd who were recruited between august 2005 and august 2007 prior to enrollment in a pulmonary rehabilitation program .
patients were included if they were : > 35 years of age ; diagnosed with copd by a pulmonary physician ; reported symptoms of breathlessness , chronic cough , and sputum production ; had a fev1/fvc < 70% and fev1 < 80% predicted ; and were able to read and write norwegian .
the exclusion criteria for the study were using long - term oxygen treatment and unstable heart disease .
patients were approached in the outpatient clinic and were given verbal and written information about the study .
in addition , all patients were asked to complete a number of self - report questionnaires and to return them in a postage paid envelope .
after 2 weeks , a reminder letter was sent to those who had not returned the questionnaires .
the study was approved by the hospital unit , the regional committee for medical research ethics , and the norwegian social science data services .
patients completed a demographic questionnaire that obtained information on age ( continuous variable in years ) , sex ( male , female ) , education ( primary school , secondary school , and university ) , marital status ( married / partnered , unmarried , widowed , divorced / separated ) , employment status ( full or part time , not employed ) , smoking ( current smoker , previous smoker , never smoked ) , comorbidities ( yes , no ) , and other chronic medical conditions ( myocardial infarction , angina , stroke , diabetes , cancer , osteoporosis , fibromyalgia , chronic pain , rheumatoid arthritis , osteoarthritis , ankylosing spondylitis , skeletal / muscle diseases , psychiatric diagnosis , gastrointestinal disease , asthma ) .
spirometry was performed with a vitalograph alpha spirometer ( vitalograph alpha , lenexa , ks ) , according to published guidelines.12 forced expiratory volume in one second ( fev1 ) and forced vital capacity ( fvc ) were measured and the predicted values calculated according to a norwegian reference population.13 fev1 ( l ) and fev1 as a percentage of the predicted value ( predicted fev1% ) were used as a measure of lung function .
disease severity was classified using the global initiative for copd ( gold ) criteria : mild , moderate , severe , and very severe copd , defined as fev1/fvc < 0.7 , fev1 80% predicted , fev1 50%80% predicted , fev1 50%30% predicted , or fev1
< 30% predicted , respectively.14 breathlessness was measured with the st george s respiratory questionnaire ( sgrq).15 sgrq is a disease - specific questionnaire that measures health status for patients with pulmonary disease .
the questionnaire consists of 76 items divided into three components : symptoms , activity , and impact .
each of the component scores can range from 0 to 100 , with lower scores indicating better health status.1618 the sgrq has been translated into different languages and has satisfactory reliability and validity in copd patients.1921 as was done in previous studies,15,18 the symptom component score was used as the measure of breathlessness .
the symptom component consists of eight items , including frequency and distress from breathlessness in terms of phlegm / sputum , shortness of breath , wheezing , and chest trouble.15,18 in addition , the following individual breathlessness items were evaluated : my cough hurts ; my cough makes me tired ; i get breathless when i bend over ; my cough or breathing disturbs my sleep ; and i get exhausted easily .
each item was scored using the 0 ( wrong ) versus 1 ( right ) format .
the symptom component score , as well as the individual item scores , were used to evaluate differences in cough and breathlessness in copd patients with and without pain .
patients were categorized into the pain versus no pain groups based on their responses to the following question : are you generally bothered by pain ? data were analyzed using spss ( v16.0 ; spss inc , chicago , il ) .
descriptive statistics were used to evaluate demographic , clinical , respiratory , and pain variables .
chi - square and independent sample t - tests were used to evaluate for differences in demographic and clinical characteristics , and respiratory parameters between copd patients who did and did not have pain .
multiple logistic regression analysis was done to evaluate the impact of specific respiratory parameters ( ie , breathlessness and lung function ) on pain status ( ie , having or not having pain ) after controlling for clinical characteristics ( ie , number of comorbidities ) that showed significant bivariates association with pain .
patients completed a demographic questionnaire that obtained information on age ( continuous variable in years ) , sex ( male , female ) , education ( primary school , secondary school , and university ) , marital status ( married / partnered , unmarried , widowed , divorced / separated ) , employment status ( full or part time , not employed ) , smoking ( current smoker , previous smoker , never smoked ) , comorbidities ( yes , no ) , and other chronic medical conditions ( myocardial infarction , angina , stroke , diabetes , cancer , osteoporosis , fibromyalgia , chronic pain , rheumatoid arthritis , osteoarthritis , ankylosing spondylitis , skeletal / muscle diseases , psychiatric diagnosis , gastrointestinal disease , asthma ) .
spirometry was performed with a vitalograph alpha spirometer ( vitalograph alpha , lenexa , ks ) , according to published guidelines.12 forced expiratory volume in one second ( fev1 ) and forced vital capacity ( fvc ) were measured and the predicted values calculated according to a norwegian reference population.13 fev1 ( l ) and fev1 as a percentage of the predicted value ( predicted fev1% ) were used as a measure of lung function .
disease severity was classified using the global initiative for copd ( gold ) criteria : mild , moderate , severe , and very severe copd , defined as fev1/fvc < 0.7 , fev1 80% predicted , fev1 50%80% predicted , fev1 50%30% predicted , or fev1
breathlessness was measured with the st george s respiratory questionnaire ( sgrq).15 sgrq is a disease - specific questionnaire that measures health status for patients with pulmonary disease .
the questionnaire consists of 76 items divided into three components : symptoms , activity , and impact .
each of the component scores can range from 0 to 100 , with lower scores indicating better health status.1618 the sgrq has been translated into different languages and has satisfactory reliability and validity in copd patients.1921 as was done in previous studies,15,18 the symptom component score was used as the measure of breathlessness .
the symptom component consists of eight items , including frequency and distress from breathlessness in terms of phlegm / sputum , shortness of breath , wheezing , and chest trouble.15,18 in addition , the following individual breathlessness items were evaluated : my cough hurts ; my cough makes me tired ; i get breathless when i bend over ; my cough or breathing disturbs my sleep ; and i get exhausted easily .
each item was scored using the 0 ( wrong ) versus 1 ( right ) format .
the symptom component score , as well as the individual item scores , were used to evaluate differences in cough and breathlessness in copd patients with and without pain .
patients were categorized into the pain versus no pain groups based on their responses to the following question : are you generally bothered by pain ?
data were analyzed using spss ( v16.0 ; spss inc , chicago , il ) .
descriptive statistics were used to evaluate demographic , clinical , respiratory , and pain variables .
chi - square and independent sample t - tests were used to evaluate for differences in demographic and clinical characteristics , and respiratory parameters between copd patients who did and did not have pain .
multiple logistic regression analysis was done to evaluate the impact of specific respiratory parameters ( ie , breathlessness and lung function ) on pain status ( ie , having or not having pain ) after controlling for clinical characteristics ( ie , number of comorbidities ) that showed significant bivariates association with pain .
of the 136 patients who met the inclusion criteria , 100 accepted the invitation to participate in this study ( response rate of 74% ) .
no differences were found in the age ( p = 0.60 ) or sex distribution ( p = 0.92 ) of the patients who did and did not participate in this study .
of the 100 copd patients who participated in the study , 45% responded yes to the question are you generally bothered by pain ? as shown in table 1 , no significant differences were found in any demographic characteristics between copd patients who did and did not have pain . as shown in table 2 , compared to patients without pain , copd patients with pain were more likely to report the presence of a comorbidity ( p = 0.016 ) ; had a significantly higher number of comorbidities ( p < 0.001 ) ; and reported a higher breathlessness score on sgrq ( p = 0.003 ) . in terms of self - reported occurrence of chronic medical conditions ( see table 3 ) , a higher percentage of copd patients with pain reported chronic pain ( 22% ; p < 0.001 ) and musculoskeletal diseases ( 24% ; p = 0.003 ) compared to those who did not have pain .
as shown in figure 1 , a significantly higher percentage of patients who had pain endorsed the following breathlessness items : my cough makes me hurt
( p = 0.027 ) . as shown in table 4 , based on the results of the logistic regression analysis , after adjusting for the number of comorbidities ( or = 0.28 ; p = 0.026 ) , greater breathlessness measured by the sgrq symptom score ( or = 1.03 ; p = 0.003 ) was significantly associated with pain , while lung function ( or = 1.03 ; p = 0.052 ) was nearly significant .
the model fit showed that number of comorbidities , breathlessness and lung function explained 23% ( nagelkerke r - square ) of the variability in pain .
the hosmer and lemeshow test statistic indicated that goodness of fit to the model was satisfactory .
as shown in table 1 , no significant differences were found in any demographic characteristics between copd patients who did and did not have pain . as shown in table 2 , compared to patients without pain , copd patients with pain were more likely to report the presence of a comorbidity ( p = 0.016 ) ; had a significantly higher number of comorbidities ( p < 0.001 ) ; and reported a higher breathlessness score on sgrq ( p = 0.003 ) . in terms of self - reported occurrence of chronic medical conditions ( see table 3 ) , a higher percentage of copd patients with pain reported chronic pain ( 22% ; p < 0.001 ) and musculoskeletal diseases ( 24% ; p = 0.003 ) compared to those who did not have pain .
as shown in figure 1 , a significantly higher percentage of patients who had pain endorsed the following breathlessness items : my cough makes me hurt ( p = 0.004 ) ; my cough makes me tired
as shown in table 4 , based on the results of the logistic regression analysis , after adjusting for the number of comorbidities ( or = 0.28 ; p = 0.026 ) , greater breathlessness measured by the sgrq symptom score ( or = 1.03 ; p = 0.003 ) was significantly associated with pain , while lung function ( or = 1.03 ; p = 0.052 ) was nearly significant .
the model fit showed that number of comorbidities , breathlessness and lung function explained 23% ( nagelkerke r - square ) of the variability in pain .
the hosmer and lemeshow test statistic indicated that goodness of fit to the model was satisfactory .
this study is the first to evaluate for differences in subjective and objective respiratory parameters in copd patients with or without pain .
it is interesting that after adjusting for the number of comorbidities , the copd patients with pain reported significantly higher breathlessness scores compared to those who did not report pain .
in contrast , similar associations were not found for pain and the objective measure of lung function .
these findings are consistent with two previous reports that used similar measures.5,6 in addition , findings across these quantitative studies are consistent with a recent qualitative study of copd patients who were interviewed about their pain experiences .
some of these patients described their pain as tying up the body , which makes it impossible to breathe normally and in turn resulted in increased pain.4 a growing body of evidence suggests that these distinctly different sensations share important characteristics .
the relationship between pain and breathlessness may be partially explained by the fact that these sensations are mediated within a larger brain network in the anterior insula .
both sensations alert the brain and motivate adaptive behaviors.9 additional research is warranted to examine the commonalities and differences in these two sensations . in this study ,
a significantly higher percentage of copd patients with pain reported that their cough made them hurt , that their cough made them tired , that breathlessness / cough disturbed their sleep , and that they became exhausted easily .
these findings are consistent with a study by williams and colleagues,22 which found that patients with copd reported that breathlessness was painful , made them tired and weak , and led to general exhaustion .
again , the association between these respiratory descriptors and pain provide additional evidence that breathlessness and pain may share more than common cortical pathways.9 pain is a complex symptom that is caused by many different bodily changes.23 copd is a complex progressive lung disease .
as the disease progresses , elastic tissues in the lung are damaged , which leads to increased mucous hypersecretion , cough , airway narrowing , decreased oxygen saturation , and breathlessness.14 these pathophysiologic changes may lead to pain , sleeplessness , fatigue , and exhaustion.4 the disease progresses the airflow limitations and decreases in ventilation may increase respiratory muscle work and the work of breathing24,25 which in turn may result in fatigue , exhaustion , and pain.4 an equally plausible hypothesis is that breathlessness and increased muscle work may lead to muscle hypertonicity and fatigue , which in turn results in increased ventilatory drive associated with greater breathlessness.4,10 a third hypothesis to explain the associations between cough , breathlessness , and pain in copd patients is that coughing can lead to pain for mechanical reasons and results in fatigue because it requires energy.4,10 all of these hypotheses warrant testing in future studies . of note ,
those copd patients who had pain reported a significantly higher number of comorbidities than those who did not have pain .
in addition , a higher percentage of copd patients with pain reported the occurrence of chronic pain and musculoskeletal disorders .
as is seen in patients with other chronic medical conditions,26,27 patients with copd may have pain associated with copd , pain associated with other chronic medical conditions , and/or pain associated with both their copd and other chronic medical conditions .
additional research is warranted to determine the specific and/or multiple etiologies for pain in patients with copd .
a surprising finding was that no differences were found in any demographic characteristics ( eg , age , sex , education , marital status , employment status ) between copd patients with and without pain .
these findings differ from a previous study of pain in the general norwegian population,28 which found that being younger , being female , having less formal education , living alone , and being unemployed were associated with chronic pain .
the reasons for these differences are not readily apparent and warrant investigation in future studies .
several study limitations need to be acknowledged . because of the relatively small sample size , additional differences in both subjective and objective respiratory parameters between copd patients with and without pain warrant investigation in future studies . according to the biopsychosocial model , pain
is associated with physiologic as well as psychosocial factors.2931 therefore , future studies with larger samples may determine additional demographic and sociocultural characteristics associated with pain group membership . finally , the copd patients in this study were about to begin a pulmonary rehabilitation program .
therefore , this sample that consisted of patients who had primarily moderate to severe copd , is not a representative sample of all copd patients . despite the low sample size in this study
, breathlessness is associated with pain , which indicates that increased breathlessness may result in pain . by striving for greater understanding of the relationship between breathlessness and pain
, the authors suggest that there should be a stronger focus on the relationship between breathlessness and pain when precise and effective copd interventions are planned .
in conclusion , the findings from this study suggest that pain is a significant problem in patients with copd . in addition , copd patients who had pain reported a higher number of comorbidities and breathlessness than copd patients who did not have pain .
additional research is warranted to more completely characterize the causes and multiple dimensions of the pain experience of patients with copd during various stages of their disease and treatment .
a stronger focus on the relationship between breathlessness and pain when precise and effective copd interventions are planned is recommended . | ### Summary:
: backgroundfew studies have evaluated the associations between respiratory parameters and pain in chronic obstructive pulmonary disease ( copd ) .
the purpose of this study is to evaluate the differences in respiratory parameters between copd patients who did and did not have pain.methodsin this cross - sectional study respiratory parameters were measured by spirometry and the st georges respiratory questionnaire .
patients responded to a single question that asked if they were generally bothered by pain.resultsof the 100 patients , 45% reported that they were generally bothered by pain .
patients who had pain reported a higher number of comorbidities ( p < 0.001 ) and higher breathlessness scores ( p = 0.003 ) .
physical dimensions of breathlessness were significantly associated with pain ( p 0.03 ) .
the results of logistic regression analysis determined that a higher number of comorbidities ( or = 0.28 ; p = 0.026 ) and higher breathlessness scores ( or = 1.03 ; p = 0.003 ) made significant unique contributions to the prediction of pain group membership.conclusionscomorbidity and breathlessness were risk factors for pain and the physical dimensions of breathlessness were associated with pain . |
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: periodontitis is the most common adult chronic inflammatory disorder , which results in a consequence of the persistent systemic inflammatory responses [ 1 , 2 ] .
porphyromonas gingivalis ( p.g . ) is the major periodontopathic bacteria [ 3 , 4 ] , and its lps ( p.g .
lps ) is thought to induce periodontitis through toll - like receptors , tlr2 or tlr4 . as the main population in inflammatory oral mucosa ,
lps - induced oral innate immune responses through tlrs during chronic periodontitis [ 5 , 6 ] .
m1 macrophages promote inflammation and tissue damage by secreting proinflammatory mediators , including tnf- , il-1 , and expressing inducible no synthase ( inos ) .
in contrast , m2 macrophages promote anti - inflammation and wound healing by secreting anti - inflammatory mediators , including il-10 and tgf-1 , and upregulating arginase 1 ( arg 1 ) [ 8 , 9 ] .
in addition to causing chronic systemic inflammatory diseases , including atherosclerosis , cardiovascular disease , and diabetes [ 1012 ] , periodontitis has been proposed as a risk factor for the central nervous system ( cns ) disorders , such as alzheimer 's disease ( ad ) [ 1315 ] .
however , the exact route by which periodontitis transduces the peripheral inflammatory messages into the cns remains unclear . besides the physical role as the cerebrospinal fluid - blood barrier [ 16 , 17 ]
, the leptomeninges also play roles as secretory cells , which transduce systemic inflammatory signals into the cns [ 1820 ] .
furthermore , tlr2 and tlr4 are detected in cultured human leptomeningeal cell lines and leptomeninges of experimental animals [ 22 , 23 ] , suggesting that leptomeninges are involved in the innate response of the cns .
moreover , increasing evidence shows that microglia are the primary brain cells that respond to systemic inflammatory stimuli to play their well - known roles in neuroinflammation [ 2427 ] .
the chemical composition of propolis depends on the local flora at the site of collection [ 28 , 29 ] .
considering its antioxidative and anti - inflammatory effects [ 3032 ] , propolis may have protective effects against neuroinflammatory responses . in the present study ,
we have attempted to examine possible roles of leptomeninges in transducing inflammatory signals from peripheral macrophages to brain - resident microglia in response to p.g .
the mean amounts of tnf- and il-1 secreted by leptomeningeal cells after treatment with the conditioned medium from p.g .
furthermore , the mean amounts of tnf- and il-1 secreted by microglia after treatment with the conditioned medium from p.g .
these observations suggest that leptomeninges transduce inflammatory signals from peripheral macrophages to brain - resident microglia by secreting inflammatory mediators during chronic periodontitis .
lps - induced tnf- and il-1 production by leptomeningeal cells through inhibiting the nuclear factor-b ( nf-b ) signaling pathway . together with our recent findings of direct inhibitory effects on the microglial inflammatory responses ,
p.g . lps were purchased from invivogen ( san diego , ca , usa ) .
propolis was purchased from yamada bee farm corporation ( okayama , japan ) , function blocking antibodies to tlr2 , tlr4 and isotype control antibodies were purchased from ebioscience ( san diego , ca , usa ) .
bay 11 - 7082 , a specific nf-b inhibitor , was purchased from sigma - aldrich ( st . louis mo , usa ) .
antibodies of mouse anti - tlr2 ( t2.5 ) , mouse anti - tlr4 ( hta-125 ) were purchased from ebioscience ( san diego , ca , usa ) .
mouse anti - phospho - ib , rabbit anti - ib , goat anti - tnf- , and rabbit anti - actin were purchased from santa cruz biotechnology ( delaware avenue santa cruz , ca ) .
mouse anti - inos ( 4e5 ) was purchased from abcam ( heidelberg , germany ) .
rabbit anti - ionized calcium binding adaptor molecule ( iba1 ) was purchased from wako chem industries ltd ( osaka , japan ) .
the periodontal diagnosis of subjects with chronic periodontitis was established based on clinical and radiographic criteria defined by the 1999 international world workshop for a classification of periodontal diseases and conditions .
the samples included 9 cases diagnosed as chronic periodontitis ( aged 3460 , 6 males and 3 females ) , which were recruited from periodontology department of school of stomatology , jilin university .
following surgery , excised gingival specimens were immediately placed in liquid nitrogen and subsequently frozen at 80c until the following experiments .
gingival samples were immersed in the periodate lysine paraformaldehyde ( plp ) fixative consisting of 0.01 m sodium metaperiodate , 0.075 m l - lysine - hcl , 4% paraformaldehyde , and 0.03% phosphate buffer ( ph 6.2 ) for 6 h at 4c .
the specimens were cryoprotected 2 days in 30% sucrose in phosphate - buffered saline and then were embedded in an optimal cutting temperature compound ( sakura finetechnical co. , ltd . ,
serial coronal frozen sections ( 14 m ) were subjected to the immunohistochemical analyses [ 34 , 35 ] .
the sections were hydrated and treated with 10% donkey serum for 1 h at 24c and then were incubated with each primary antibody overnight at 4c . the primary mouse monoclonal anti - tlr2 ( t2.5 , 1 : 200 ) ,
mouse monoclonal anti - tlr4 ( hta-125 , 1 : 200 ) , goat polyclonal anti - tnf- ( 1 : 200 ) , and mouse monoclonal anti - inos ( 4e5 , 1 : 500 ) antibodies were mixed with rabbit polyclonal anti - iba1 ( 1 : 500 ) antibody . after washing with pbs , the sections were incubated with a mixture of fitc - conjugated and rhodamine - conjugated secondary antibodies for 2 h at 24c .
after washing , the sections were mounted in the antifading medium vectashield ( vector laboratory ) and examined by a confocal laser scanning microscope ( clsm ) lsm510met ( clsm , c2si , nikon , japan ) .
clsm images of individual sections were taken as a stack at 1 m step size along z - direction with 20 objectives ( numerical aperture = 0.5 ) , zoom factor 1.0 . a rectangle ( 1024 1024 pixels ) corresponding to the size of 450 450 m
thp-1 cells which were purchased from the atcc ( manassas , va , usa ) were cultured in rpmi-1640 medium supplemented with 10% fetal bovine serum ( fbs , icn biomedicals , eschwege , germany ) , 0.05 mm 2-mercaptoethanol , penicillin g ( 40 u / ml ) , and streptomycin ( 50 g / ml ) .
raw264.7 cells which were purchased from the atcc were cultured in minimum essential medium alpha ( mem- , gibco , usa ) supplemented with 10% fbs , penicillin g
( 40 u / ml ) , and streptomycin ( 50 g / ml ) ; those cells were cultured at 37c in a humidified atmosphere with 5% co2 .
dissected leptomeningeal tissues were plated on poly - d - lysine - coated culture dishes ( one mouse / mm ) and incubated in dulbecco 's modified eagle 's medium ( dmem , nissui pharmaceutical co. , ltd . ,
japan ) containing 10% fbs , penicillin g ( 40 u / ml ) , and streptomycin ( 50 g / ml ) at 37c in a humidified atmosphere with 5% co2 for 7 days . at this time ,
any contaminated cells such as neuronal and glial cells were removed by shaking and were washed twice with ca / mg - free sterile isotonic buffer , ph 7.0 , which consisted of 137 mm nacl , 5 mm kcl , 0.7 mm kh2po4 , 25 mm glucose , 59 mm sucrose , 0.3% bovine serum albumin , penicillin ( 40 u / ml ) , and streptomycin ( 50 g / ml ) .
the purity of the leptomeningeal cells was more than 96% as determined by the immunostaining of fibronectin [ 18 , 19 ] .
the c - myc - immortalized mouse microglial cell line , mg6 ( riken cell bank , tsukuba , japan ) , was maintained in dmem containing 10% fbs supplemented with 100 m -mercaptoethanol , 10 g / ml insulin , 100 g / ml streptomycin , and 100 u / ml penicillin ( bd falcon , franklin lakes , nj ) [ 36 , 37 ] .
lps ( 1 g / ml ) for 24 h , leptomeningeal cells were incubated with the conditioned medium from p.g .
lps - treated raw264.7 cells ( mcm ) for 4 h , and mg6 were incubated with the conditioned medium from p.g .
lps - treated leptomeningeal cells ( lcm ) for 24 h. the mrna isolated from p.g .
lps - treated or nontreated cells were subjected to real - time quantitative rt - pcr .
the total rna was extracted with the purelink rna microkit ( invitrogen , japan ) according to the manufacturer 's instructions .
a total of 800 ng of extracted rna was reverse transcribed to cdna using the high capacity rna - to - cdna master mix ( applied biosystems , foster city , ca ) .
the thermal cycling was held at 50c for 2 min , and then at 95c for 10 min , followed by 40 cycles of 95c for 15 s and 60c for 1 min .
the cdna was amplified in duplicate using taqman universal pcr master mix ( applied biosystems , foster city , ca ) with an applied biosystems 7500/7500 fast real - time pcr system . the data were evaluated using the 7500 software program ( version 2.0 , applied biosystems ) .
the primer sequences used were as follows : inos : 5-gcc acc aac aat ggc aac a-3 and 5-cgt acc gga tga gct gtg aat t-3 ; arginase-1
: 5-cgc ctt tct caa aag gac ag-3 and 5-cca gct ctt cat tgg ctt tc-3 ; tnf- : 5-atg gcc tcc ctc tca gtt c-3and 5-ttg gtg gtt tgc tac gac gtg-3 ; il-1 : 5-caa cca aca agt gat att ctc cat g-3 and 5-gat cca cac tct cca gct gca-3 ; il-10 : 5-atg ctg cct gct ctt act gac tg-3 and 5-ccc aag taa ccc tta aag tcc tgc-3. for data normalization , an endogenous control ( actin ) was assessed to control for the cdna input , and the relative units were calculated by a comparative ct method .
all real - time rt - pcr experiments were repeated three times , and the results are presented as the means of the ratios sem .
lps ( 1 g / ml ) , leptomeningeal cells were treated with p.g .
lps ( 100 ng / ml ) , and the condition medium was collected at 6 h , 24 h , 48 h , and 72 h after p.g .
raw264.7 were incubated with propolis ( 15 g / ml ) 1 h before p.g .
lps treatment , and the condition medium was collected at 48 h after treatment .
the leptomeningeal cells were incubated with propolis ( 10 g / ml ) 1 h before p.g .
lps treatment , and the condition medium was collected at 6 h after treatment . in the separated experiments , raw264.7 , leptomeningeal cells , and mg6
were treated with tlr2 ( 10 g / ml ) , tlr4 ( 10 g / ml ) antibodies or the control antibodies or bay 11 - 7082 ( 20 m ) 1 h before p.g .
tnf- and il-1 released from thp-1 , raw264.7 , leptomeningeal cells , and mg6 were measured using enzyme - linked immunosorbent assay ( elisa ) kits ( r&d systems ) following the protocol provided by the manufacturer .
raw264.7 and leptomeningeal cells were seeded in 96-well plates for 24 h ( 5 10 cells / well ) then incubated with various concentrations of propolis for 48 h. cell viability was assessed using the cell - counting kit-8 ( cck-8 ) ( dojindo , kumamoto , japan ) according to the manufacturer 's instructions . briefly , after propolis treatment , 10 l cck-8 was added to each well and incubated at 37c for 2 h. the optical density was read at a wavelength of 450 nm with a microplate reader .
cell viability was calculated using the following formula : optical density of treated group / control group 100% .
raw264.7 and leptomeningeal cells were cultured at a density of 5 10 cells / ml , and the cytosolic samples of raw264.7 and leptomeningeal cells were collected at 30 min , 60 min , and 120 min after p.g .
lps ( 1 g / ml , 100 ng / ml ) treatment with or without propolis ( 15 g / ml , 10 g / ml ) .
the samples were electrophoresed in 12% sds - polyacrylamide gels , and the proteins on sds gels were transferred electrophoretically to nitrocellulose membranes .
following the blocking , the membranes were incubated at 4c overnight under gentle agitation with each primary antibody : rabbit anti - ib ( 1 : 1000 ) , mouse anti - pib ( 1 : 1000 ) antibodies .
after washing , the membranes were incubated with horseradish peroxidase ( hrp- ) labeled anti - rabbit ( 1 : 2000 , ge healthcare , uk ) or anti - mouse ( 1 : 2000 , ge healthcare , uk ) antibodies for 2 h at 24c , then the protein bands were detected by an enhanced chemiluminescence detection system ( eck kit , amersham pharmacia biotech ) using an image analyzer ( las-4000 , fuji photo film , tokyo , japan ) .
the statistical analyses were performed using a one - way or two - way analysis of variance ( anova ) with a post hoc tukey 's test using the graphpad prism software package . a value of p < 0.05 was considered to indicate statistical significance ( graphpad software inc . , san diego , ca , usa ) .
we first examined the localization of tlr2 , tlr4 , and cytokines in human gingival tissues of chronic periodontitis patients , because macrophages are the main population in gingival tissues of chronic periodontitis to response p.g .
our immunofluorescent double staining revealed that the immunoreactivities for tlr2 , tlr4 , tnf- , and inos corresponded well with those for iba1 ( figure 1(a ) ) and their correspondence ratios were 72% , 79% , 53% , and 65% , respectively .
however , immunoreactivities for il-10 and tgf-1 were rarely found in human periodontitis gingival tissues ( data not shown ) .
lps using thp-1 human monocyte - like cell line and raw264.7 mouse macrophages . in comparison to the nontreated cells , both the mean mrna expression levels of tnf- and inos were significantly increased in thp-1 cells after treatment with p.g .
however , mean mrna expression levels of il-10 and arg 1 were not significantly increased after treatment with p.g . lps ( figure 1(b ) ) .
furthermore , the time - dependent release of tnf- and il-1 from raw264.7 cells was induced from 6 h and peaked at 48 h and then was decreased gradually later after p.g .
the similar results were also obtained in thp-1 cells ( data not shown ) . moreover , p.g .
lps - induced tnf- and il-1 production in raw264.7 cells was significantly suppressed by anti - tlr2 antibody , but not by anti - tlr4 antibody ( figure 1(d ) ) . on the other hand , the control antibodies with the same concentration had no significant effect ( data not shown ) .
we next used mouse primary cultured leptomeningeal cells to address whether they could respond to inflammatory mediators secreted from p.g .
surprisingly , the mean expression levels of tnf- and il-1 mrna in leptomeningeal cells were significantly increased from 4 h after treatment with mcm in comparison to those observed after treatment with p.g .
furthermore , in comparison to the nontreated cells , the secretion of tnf- and il-1 from leptomeningeal cells peaked at 6 h , decreased quickly , and it is noted that tnf- was undetected at 48 h after treatment with p.g .
lps was significantly suppressed by anti - tlr2 antibody , but not by anti - tlr4 antibody ( figure 2(c ) ) . on the other hand , the control antibodies with the same concentration had no significant effect ( data not shown ) . to date ,
these observations provide the first evidence that leptomeningeal cells are polarized to proinflammatory phenotype in response to inflammatory signals from p.g .
we have previously demonstrated that the leptomeninges are involved in the cytokine production by glial cells during chronic systemic inflammation [ 1820 ] . in order to confirm that the leptomeninges could trigger microglial inflammatory responses , we next examined the mrna expression of tnf- and il-1 in mg6 microglia after treatment with the conditioned medium from p.g .
the mean mrna expression levels of tnf- and il-1 were significantly increased after 24 h treatment with lcm in comparison to those observed after treatment with p.g .
the mean level of tnf- secreted by microglia was significantly increased from 6 h and peaked at 48 h after treatment with p.g .
lps ( 100 ng / ml ) in comparison to that by nontreated microglia .
the amount of il-1 secreted from microglia also reached peak at 48 h after treatment with p.g .
lps - induced secretion of tnf- by microglia was significantly suppressed by anti - tlr2 antibody , but not by anti - tlr4 antibody ( figure 3(b ) ) .
however , the control antibodies with the same concentration had no significant effect ( data not shown ) .
these observations clearly demonstrate that microglia were polarized to proinflammatory m1-like phenotype in response to inflammatory signals from p.g .
lps - induced leptomeningeal cells through tlr2 . finally , the effects of propolis on the secretion of p.g .
lps - induced proinflammatory mediators by macrophages and leptomeningeal cells were examined , because propolis has antioxidative and anti - inflammatory effects [ 31 , 32 ] .
the mean cell viability was not significantly changed with the final concentrations until 15 g / ml on raw264.7 macrophages ( figure 4(a ) ) and the final concentrations until 10 g / ml on leptomeningeal cells after treatment with propolis ( figure 4(d ) ) .
therefore , we used propolis with the concentration of 15 g / ml on raw264.7 and 10 g / ml on leptomeningeal cells , respectively , for the following experiments . in comparison to the nontreated cells , pretreatment with propolis significantly inhibited tnf- secretion by macrophages ( figure 4(b ) ) and leptomeningeal cells ( figure 4(e ) ) after treatment with p.g
lps - induced nf-b activation were then examined , because nf-b regulates the expression of proinflammatory mediators , including tnf- and il-1. the expression of ib phosphorylation was significantly increased from 30 min in both raw264.7 and leptomeningeal cells after treatment with p.g .
lps - induced phosphorylation of ib in raw264.7 cells ( figure 4(c ) ) and leptomeningeal cells ( figure 4(f ) ) .
lps - induced proinflammatory responses by inhibiting the nf-b signaling pathway in both peripheral macrophages and leptomeningeal cells .
lps - induced inflammatory signals from peripheral macrophages to brain - resident microglia , resulting in the induction of neuroinflammation .
lps - induced proinflammatory mediators by leptomeningeal cells . to date , this is the first report to highlight that the leptomeninges serve as an important route for transducing peripheral inflammatory signals to the cns during chronic periodontitis . as the main population in inflammatory oral mucosa , macrophages phenotypes are known to determine p.g .
lps - induced oral innate immune responses through tlrs during periodontitis . in the present study
, we confirmed that macrophages densely expressed tlr2 , tlr4 , tnf- , and inos in the gingival tissues of chronic periodontitis patients .
however , proinflammatory m1 macrophages are not limited to the infected gingiva but also increased in the circulation during chronic periodontitis [ 39 , 40 ] .
lps stimulation significantly increased the mean levels of mrna expression of tnf- and inos , but not those of il-10 and arg1 , suggesting that macrophages are polarized to m1 phenotype in response to p.g . lps during chronic periodontitis .
furthermore , the mean amounts of p.g . lps - induced tnf- and il-1 secreted by macrophages were significantly suppressed by anti - tlr2 antibody , but not by anti - tlr4 antibody , further indicating that macrophages respond to p.g .
lps mainly through tlr2 [ 38 , 41 , 42 ] , but not through tlr4 [ 5 , 42 ] .
systemic inflammation and infections could worsen a number of cns disorders [ 26 , 43 ] . among the common chronic inflammatory disorders in adults ,
much attention has been paid to the periodontitis as the pathogenesis of cns disorders , including ad [ 13 , 15 , 44 ] .
the increase in macrophage - derived tnf- and il-1 in the circulation during periodontitis [ 39 , 40 ] also supports the idea that chronic periodontitis is involved in the pathogenesis of systemic inflammatory diseases , including atherosclerosis , cardiovascular disease , and diabetes [ 1012 ] .
therefore , it is reasonable to consider that the increased m1 polarization of macrophages during chronic periodontitis can be also a risk factor for ad , because the elevated levels of tnf- and il1- are associated not only with the cognitive decline but also with the progression of ad [ 4547 ] .
recently , we have reported that leptomeninges provide a critical link between chronic systemic inflammation and subsequent neuroinflammation [ 1820 ] . in the present study
lps stimulates both thp-1 and raw264.7 macrophages to secrete tnf- and il-1. furthermore , the mean mrna expression levels of tnf- and il-1 in leptomenigeal cells were significantly increased as early as 4 h after treatment with mcm .
these observations indicate that leptomenigeal cells could respond to proinflammatory mediators secreted from m1 macrophages during chronic periodontitis .
lps also stimulates leptomeningeal cells to produce tnf- and il-1 , which is consistent with previous studies using e coli lps [ 18 , 19 ] and other meningitis causable agents [ 4850 ] . importantly , unlike peripheral macrophages , leptomeningeal cells produce tnf- and il-1 from 6 h after treatment with p.g .
lps more sensitively than peripheral macrophages through tlr2 , but not through tlr4 , even though tlr4 is also expressed in meningeal cells [ 21 , 23 ] .
microglia are well - known key players of neuroinflammation [ 26 , 27 ] , which are activated by tnf- and il-1 in an autocrine manner [ 51 , 52 ] .
the present findings indicate that lcm significantly enhanced the mrna expression of tnf- and il-1 in microglia , suggesting that proinflammatory mediators secreted from p.g .
lps - treated leptomenigeal cells could subsequently activate microglia to generate neuroiflammation during chronic periodontitis .
furthermore , our present observations demonstrate that the mean levels of tnf- and il-1 secreted by microglia were significantly increased after treatment with p.g .
lps - induced secretion of proinflammatory mediators by microglia was significantly suppressed by anti - tlr2 antibody .
therefore , it is reasonable to consider that leptomenigeal cells may transduce the periodontitis - derived inflammatory signals to microglia , resulting in powerful neuroninflammatory responses .
further investigations will be necessary to examine a possible involvement of other glial cells during chronic periodontitis , because other glial cells , such as astrocytes , also contribute to the cns disorders [ 54 , 55 ]
. moreover , further investigations are necessary to clarify the involvement of other factors in neuroinflammation during chronic periodontitis , because p.g .
neuroprotective drug therapies have not yet translated well from the lab to the clinic because of an excessive focus of treatments on promoting the survival of neurons , with far less work on nonneuronal brain cells .
recently , leptomeninges have been focused on delivering compounds / genes to brain [ 56 , 57 ] .
therefore , meninges can be considered as the direct targets for treating cns disorders , including ad .
it has relevant therapeutic properties that have been used since ancient times . depending on their antioxidative and anti - inflammatory effects [ 3032 ] ,
we here provide the first evidence that propolis can significantly inhibit tnf- and il-1 production by both raw264.7 cells and leptomenigeal cells through inhibiting the nf-b signaling pathway , because nf-b is a critical transcription factor that encodes genes of proinflammatory mediators , including tnf- and il-1 .
these findings agreed well with our previous observations that propolis significantly inhibited hypoxia - induced nf-b - dependent production of proinflammatory mediators by microglia .
recently , we have reported that the exaggerated neuroinflammatory responses evoked by microglia are responsible for an impairment of the hippocampal long - term potentiation in the middle - aged animals subjected to adjuvant arthritis .
lps - induced nf-b - dependent proinflammatory pathway of leptomeningeal cells and microglia may prevent the age - dependent exaggerated neuroinflammatory responses in the cns .
in conclusion , our present findings strongly suggest that the leptomeninges serve as an important route for transducing inflammatory signals from peripheral macrophages into brain - resident microglia by secreting proinflammatory mediators during chronic periodontitis .
propolis may benefit for preventing and reducing neuroinflammation in cns disorders , including ad , by attenuating p.g .
lps - induced inflammatory signals from peripheral macrophages , leptomeningeal cells and microglia during chronic periodontitis .
further investigations are necessary to clarify the involvement of other factors in neuroinflammation during chronic periodontitis . | ### Summary:
: we report here that the leptomeningeal cells transduce inflammatory signals from peripheral macrophages to brain - resident microglia in response to porphyromonas gingivalis ( p.g . )
lps .
the expression of toll - like receptor 2 ( tlr2 ) , tlr4 , tnf- , and inducible no synthase was mainly detected in the gingival macrophages of chronic periodontitis patients . in in vitro studies , p.g .
lps induced the secretion of tnf- and il-1 from thp-1 human monocyte - like cell line and raw264.7 mouse macrophages .
surprisingly , the mean mrna levels of tnf- and il-1 in leptomeningeal cells after treatment with the conditioned medium from p.g . lps - stimulated raw264.7 macrophages were significantly higher than those after treatment with p.g .
lps alone .
furthermore , the mean mrna levels of tnf- and il-1 in microglia after treatment with the conditioned medium from p.g .
lps - stimulated leptomeningeal cells were significantly higher than those after p.g .
lps alone .
these observations suggest that leptomeninges serve as an important route for transducing inflammatory signals from macrophages to microglia by secretion of proinflammatory mediators during chronic periodontitis .
moreover , propolis significantly reduced the p.g .
lps - induced tnf- and il-1 production by leptomeningeal cells through inhibiting the nuclear factor-b signaling pathway . together with the inhibitory effect on microglial activation ,
propolis may be beneficial in preventing neuroinflammation during chronic periodontitis . |
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: congenital cholesteatoma ( cc ) can occur in any part of the temporal bone and the commonest site being in the middle ear , most probably due to its early presentation with conductive hearing loss [ 1 , 2 ] .
however , it only accounts for 25% of all cholesteatomas and 0.21.5% of all intracranial tumors .
the common presentation of cc is hearing loss , transient otorrhea , otalgia and ear fullness .
rarely , it can present with mastoid sub - periosteal abscess especially in older children due to long - standing complications .
a 5-year - old boy presented with progressive left supra - auricular swelling for 2 weeks associated with left ear pain and low - grade fever .
there were no complaints of ear discharge or hearing impairment by the child or parents .
clinical examination showed a fluctuant mass measured 2 3 cm at the left supra - auricular region that was consistent with abscess .
tympanogram showed type b with failed auditory brainstem response on the affected side and normal hearing on the right side .
high - resolution computerized tomography ( hrct ) of temporal bone revealed soft tissue mass in middle ear cleft and ossicular destruction suggestive of cholesteatoma and luc 's abscess formation at left temporal bone ( fig . 1 ) .
further exploration of middle ear and mastoid cavity revealed cholesteatoma eroding all ossicles and involving mastoid bone . modified radical mastoidectomy was done ( fig . 2 ) .
axial image demonstrates luc 's abscess at left temporal region with soft tissue density and ossicular destruction .
axial image demonstrates luc 's abscess at left temporal region with soft tissue density and ossicular destruction .
cc is defined as cyst line by stratified squamous epithelium with keratin filled debris which is capable of surrounding tissue destruction as it expands .
this property of tissue destruction thought to be mediated by pressure - induced bone resorption and enzymatic dissolution of bone by cytokine - mediated inflammation . in 1965 , derlacki and clemis proposed criteria for cc as a cholesteatoma discovered behind an intact tympanic membrane with no history of otorrhea , prior otological intervention or previous perforations . however , there are some exceptions to these criteria when patients presents with previous history of acute otitis media or as a suppurative complication of csom such as mastoiditis and sub - periosteal abscess [ 4 , 6 ] . therefore
, underlying cc should always be suspected in children presenting with sub - periosteal abscess as a first symptom .
this fact is supported by migirov et al . who reviewed seven cases of cc patients presenting with mastoid sub - periosteal abscess .
in our case , cc was not suspected as the cause for luc 's abscess due to its rare clinical presentation .
the definite diagnosis of cc was established after a high - resolution computer tomography of temporal bone and confirmed by surgical exploration . in pre - antibiotic era , luc 's abscess often presented as a complication of otitis media and its incidence since then has dramatically reduced with widespread usage of broad spectrum antibiotics [ 7 , 8 ] . in 1900 , henri luc described it as a sub - periosteal temporal abscess of otitic origin without intraosseous suppuration and suggested the possible pathway of microorganism spread from middle ear submucosa by anatomical pathways especially via the superior meatus , incisura rivinus and along the branches of deep auricular artery . later this theory was supported by le marc hadour and chauveau in 1910 and they proposed three stages of periosteal involvement in the middle ear infection namely juxtatympanic stage , progression to entire circumference of canal skin and finally spread to sub - periosteum of temporal bone .
this is crucial in assessing the location , extent of disease , identifying anatomical variations and for appropriate operative planning as evident by our case . in the absence of cc
, luc 's abscess can be easily treated by limited surgical procedures either by pus drainage through an incision in the superior part of the external auditory meatus or through retroauricular incision combined with myringotomy and grommet insertion [ 7 , 8 ] . in this case
, patient underwent luc 's abscess drainage via retroauricular approach followed by a modified radical mastoidectomy to remove all disease and to prevent future recurrence . | ### Summary:
: congenital cholesteatoma ( cc ) rarely presents with luc 's abscess . as a result of widespread usage of antimicrobial agents ,
luc 's abscess is hardly encountered in current clinical practice .
herein , we report a case of luc 's abscess as the first presenting symptom in a 5-year - old boy with underlying cc .
patient 's clinical findings , radiological investigations and treatment were also discussed . |
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: renal cell carcinoma ( rcc ) is the most common malignancy of human kidney and accounts for approximately 2% of adult malignancies .
the von hippel - lindau ( vhl ) gene alterations are responsible for a rare hereditary cancer syndrome , including inherited rcc . the vhl gene and its importance in regulation of the hypoxia pathway through the hypoxia inducible factors ( hifs ) , the vhl disease is an uncommon autosomal dominant disorder with high penetrance , which predisposes to a variety of neoplastic and non - neoplastic lesions affecting the multiple organs .
the disease is caused by mutation of the vhl tumor suppressor gene ( vhl gene ) on the short arm of chromosome 3 ( 3p25 - 26 ) the gene spans 10 kb , is composed of three exons [ figure 1 ] and encodes two proteins ( pvhl19 and pvhl30 ) .
the complete vhl protein consists of 214 amino acids and has two structural domains : the -domain and the -domain .
( a ) the vhl gene on the short arm of the 3 chromosome ( 3p26-p25 ) , the vhl gene is located from base pair 10,183,318 to base pair 10,195,353 on chromosome 3 .
( d ) the five residues subjected for missense mutations are p.ala 65 val , p.gly 80 asp , p.gly 93 glu , p.gln 107 glu , p.gln 113 glu regulation of the expression of hif - alpha ( hif- ) by the pvhl / e3 ubiquitin ligase complex is critical for the normal functioning of a cell .
hif is composed of a -subunit ( hif- ) , which is oxygen - sensitive and a -subunit ( hif-1 ) , which is constitutively expressed . in normoxia , key proline residues within hif- are prolyl hydroxylated .
this enables recognition of hif- by the pvhl / e3 ubiquitin ligase complex and leads to polyubiquitination and degradation of hif-. in hypoxia due to the lack of available oxygen , hydroxylation of the proline residues does not occur and pvhl does not recognize hif-.
the hif- protein then translocates to the nucleus where it dimerizes with hif-1 and activates the transcription of target genes .
however , if loss of functional pvhl occurs due to the genetic or epigenetic events in normoxia , hif- is not targeted for degradation and consequently is constitutively up - regulated .
the basic biology underlying the development of clear cell renal cell carcinoma is critically dependent on the vhl gene , whose protein product is important in the cell 's normal response to hypoxia .
aberrations in vhl 's function , either through mutation or promoter hypermethylation , lead to accumulation of the transcriptional regulatory molecule , hif-. in view of the importance of vhl gene in such conditions the present study is aimed to characterize vhl in an indian patient reported in sri venkateswara institute of medical sciences ( svims ) , tirupati in the department of urology , with clear cell renal carcinoma as identified in the department of pathology .
sample was collected from patient of the department of urology ; svims university diagnosed rcc by using immunohistochemistry [ figure 2a c ] in the department of pathology .
the exon 1 of vhl gene was amplified from the genomic deoxyribonucleic acid using the primers f : 5- cct cgc ctc cgt tac-3 and r : 5- tac ctc ggt agc tgt ggat-3 which were designed from vhl gene of exon 1 reported in the genome database [ figure 3a ] . before sequencing single strand conformation polymorphism analysis showed distinct variations in the mobility of the patient polymerase chain reaction ( pcr ) product compared with normal .
therefore , the pcr amplified products were purified with nested primers - pcr purification kit , taurus scientific , usa and were sequenced ( accession number : jx401534 ) by dye terminating method at mwg biotech india ltd . thus , obtained vhl gene of exon 1 sequence
( a ) low power ( 10 ) view of clear cell renal carcinoma with few glomeruli adjacent to the lesion .
( c ) high power ( 40 ) of clear cell renal carcinoma comprised of round oval to polygonal cells with mildly pleomorphic vesicular nuclei , inconspicuous nucleoli and clear cytoplasm .
( d ) karyotyping analysis of von hippel - lindau gene mutation with clear cell renal carcinoma ( a ) polymerase chain reaction ( pcr ) amplification of exon 1 of von hippel - lindau ( vhl ) gene using vhl forward primer ( fp ) and vhl reverse primer ( rp ) primers following the method described , lane m molecular size marker obtained from bangalore genei pvt . ltd . , lane l1 pcr amplified product .
( b - d ) the chromatogram showing mutations in p.ala 65 val , p.gly 80 asp , p.gly 93 glu , p.gln 107 glu , p.gln 113 glu in exon 1 of vhl gene leading to missense mutations the sequence was basic local alignment search tool searched against the human genome sequence and the sequence showed 100% homology with vhl gene located in the chromosome 3 .
further , the sequence analysis showed five missense mutations were found in that three are novel mutations ( p.gly 80 asp , p.gln 107 glu , p.gln 113 glu ) [ table 1 and figure 3b f ] observed for the first time .
two known mutations were found changed the alanine-65 residue to valine ( p.ala 65 val ) and glycine-93 residue to glutamic acid ( p.gly 93 glu ) , respectively .
therefore , these missense mutations observed in the patient confirms the involvement of vhl gene mutation in the rcc condition .
vhl gene in exon 1 five missense mutations were identified , three are novel mutations with vhl suspected disease
the vhl gene has been found to have the characteristics of a tumor suppressor gene .
in clear cell renal carcinoma patient 's high percentage of tumors is associated with one inherited allele of the vhl gene , which is mutant and the second allele is deleted .
the product of this gene forms a complex with other proteins , especially with hif-2 results in ubiquitin mediated degradation .
mutation in the vhl gene complex can not target and degrade hif and therefore it gets accumulated and over accumulation of hif leads to increased transcription of downstream targets such as vascular endothelial growth factor , glucose transporter 1 , platelet - derived growth factor and transforming growth factor resulting in rcc .
vhl 1 ( without pheochromocytoma ) is mainly produced by mutations responsible for truncated protein ( deletions , frame shift mutations and nonsense mutations ) .
vhl type 2 ( with the high risk of pheochromocytoma ) is mainly produced by missense mutations . in the present study ,
the patient tissue sample with synchronous vhl and rcc were evaluated histologically and found to be clear cell renal carcinoma and granular carcinoma .
the mutation of the vhl gene is a frequent event in clear cell , granular and sarcomatoid renal carcinomas , but not in papillary renal carcinoma .
vhl gene sequence showed mutations in p.ala 65 val , p.gly 80 asp , p.gly 93 glu , p.gln 107 glu , p.gln 113 glu in exon 1 of vhl gene leading to missense mutations [ table 1 and figure 3b f ] .
studies showed that vhl gene mutations results in inactivation of this gene , which is observed major conventional rccs .
chromosome 3 ( 3p25 - 26 ) deletions may act as risk factors for clear cell renal carcinoma development in vhl families and they should be investigated for vhl mutations by molecular genetic testing . | ### Summary:
: von hippel - lindau ( vhl ) disease is an autosomal dominant hereditary cancer syndrome that predisposes to the development of a variety of benign and malignant tumors , especially cerebellar hemangioblastomas , retinal angiomas and clear - cell renal cell carcinomas ( rcc ) .
we have identified of vhl gene using immunohistochemistry in a patient who was diagnosed for rcc . in order to understand the involvement of mutation in the vhl gene exon 1
was amplified and sequenced ( accession number : jx 401534 ) .
the sequence analysis revealed the presence of novel missense mutations c.194 c > t , c.239 g > a , c.278 g > a , c.319 c > g , c. 337 c > g leading to the following variations p.ala 65 val , p.gly 80 asp , p.gly 93 glu , p.gln 107 glu , p.gln 113 glu in the protein . |
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: 2 ) . this behavior is unaltered by the addition of gdp or non - hydrolyzable gtp analogs .
however , gg dimerizes when incubated with either gtp or gdp in the presence of naf and alcl3 .
the requirement for the transition state mimic gdp.alf4 suggests that dimerization is important for the activation of dynamin s gtpase domain . to elucidate the role of g domain dimerization in gtp hydrolysis , we solved the structure of the gdp.alf4 -stabilized gg dimer by x - ray crystallography in two crystal forms : a " long axis " form ( fig . 1 ) and a " short axis " form ( supplementary table 1 and methods ) . in each of these structures , the gg dimer is two - fold symmetric and is formed through the association of the individual gtpase cores ( residues 32292 ) , which buries a surface area of 2561 for the long axis form ( fig .
the active sites of each monomer are positioned close to the dimer interface with the bound nucleotides oriented in a parallel fashion relative to one another .
the first involves the dual coordination of the guanine base both in cis and in trans by the g4 loop ( residues 205216 ) ( fig .
1c ) , which contains the conserved g4 element ( tkld ) that imparts nucleotide specificity via d208 s interaction with the guanine base in cis . upon dimerization ,
d211 from the adjacent monomer forms two additional hydrogen bonds with the guanine base in trans at positions 2 and 3 .
concomitantly , d211 and e212 interact with q239 and k240 across the dimer interface , partially stabilizing the conformation of residues 236246 , designated the dynamin specific loop
together these elements form a lid at the top of the dimer that caps the active sites .
the second is the association of switch ii ( residues 136153 ) with the trans stabilizing loop ( residues 176188 ) ( fig .
1d ) , mediated primarily by main chain interactions , and bolstered by interactions between v145 of switch ii and leucines 224 and 225 ( the ll patch ) and by hydrogen bonding between n183 and the main chain atoms of q40 in the p - loop .
the final stabilizing component is a pair of symmetric salt bridges between e153 and k188 that anchor the base of the dimer in trans ( fig .
efficient gtp hydrolysis requires 1 ) the correct positioning of a water molecule for a nucleophilic attack on the -phosphate , 2 ) neutralization of a negative charge that develops between the - and -phosphates in the transition state , and 3 ) stabilization of the conformationally flexible switch regions within the catalytic core23,24 .
these conditions are achieved either through interaction with a gtpase - activating protein ( gap)25,26 or through dimerization27 .
the gg dimer structure reveals how dynamin accomplishes these requirements . in the active site of each gg monomer , the main chain carbonyl of t65 and the backbone nitrogen of g139 position the catalytic water in line with the alf4 moiety ( fig .
2a ) . a second water molecule further orients the catalytic water by acting as a bridge to the q40 side chain and the g139 carbonyl oxygen .
this type of indirect positioning has thus far only been observed in the trna modifying mnme gtpase28 .
d180 of the trans stabilizing loop reaches across the dimer interface and forms hydrogen bonds with q40 , s41 , and the main chain nitrogen of g62 ( fig .
these interactions stabilize the p - loop and switch i conformations such that they are poised for catalysis .
instead , we observe additional electron density that we interpreted as a sodium ion ( supplementary fig .
the ligands for this ion include the aluminum fluoride , b - phosphate , carbonyl oxygens of g60 and g62 in switch i , and s41 side chain in the p - loop ( fig .
this pattern of coordination is similar to that of the in cis arginine finger of human guanylate binding protein 1 ( hgbp1)29 ( fig .
2c ) and the bound potassium ion in the active site of mnme ( fig .
we hypothesized that the sodium in our gg structure serves a similar purpose and indeed found that gtp hydrolysis in both gg ( supplementary fig .
3b ) and full - length dynamin ( data not shown ) is sensitive to the presence of different monovalent cations .
potassium , which is likely more physiologically relevant due to its higher intracellular concentration , induces a highesr hydrolysis rate than sodium , while rubidium and cesium impair turnover by increasing degrees . the bound magnesium ion and k44 side chain also form hydrogen bonds with the -phosphate and the aluminum fluoride ( fig .
these interactions mirror the effects of the sodium ion from the other side of the nucleotide and act in concert to stabilize the developing charge in the transition state .
this explains the strong dominant - negative effects of dynamin(k44a ) , which is defective in both gtp binding and hydrolysis5,6 .
the preponderance of backbone interactions in stabilizing the bridging and catalytic waters ( t65o , g139n ) and the bound cation ( g60o , g62o ) explains inabilities to define dynamin s basal catalytic mechanism by mutagenesis alone7,21,30 .
previous studies7,30 have nonetheless identified s45 , t65 , t141 , and k142 as important functional residues .
s45 and t65 coordinate the bound magnesium , the disruption of which would prevent proper nucleotide binding and charge compensation .
t141 in contrast does not actively contribute to the gg active site or the dimer interface , despite its location in switch ii .
however , substitutions at this position could sterically interfere with the cis and trans stabilizing loop interactions that restrict the conformational flexibility of switch ii .
indeed , t141q and t141d mutations have much stronger defects in vitro and in vivo than a smaller t141a substitution7,30 . k142a moderately impairs dynamin gtp hydrolysis but strongly inhibits endocytosis30 .
k142 can hydrogen bond with e153 at the base of the gg dimer ( fig .
superposition of gg with the rat dynamin gtpase domain ( pdb : 2aka ) reveals a number of significant conformational changes in the active site that prime dynamin for gtp hydrolysis ( fig .
the p - loop tilts by ~55 as a result of gdp.alf4 binding ( fig .
this repositions q40 and s41 , allowing them to interact with the bridging water and the sodium ion respectively .
the bound sodium engages switch i , which swings toward the nucleotide binding pocket ( fig .
r237 mediates this rearrangement by flipping towards switch i to form the center of a dense hydrogen bond network that includes the e49 , d55 , and r59 side chains and the main chain atoms of f56 , l57 and k240 ( fig .
3f ) , as has also been observed in the dynamin a structure22 ( pdb : 1jwy , fig .
this suggests that gtp hydrolysis and -phosphate release disengages switch i , which in turn would destabilize the conformation of the dsl to precipitate the break up of the dimer and allow gdp to dissociate .
additional movements in switch ii and the cis stabilizing loop ( residues 109120 ) facilitate hydrogen bonding between n112 and d147 and the backbone carbonyl of k113 and q148 in cis ( fig .
3 g ) to stabilize the conformation of switch ii and maintain its orientation at the dimer interface .
q40 , s41 , and d180 are absolutely conserved among dynamin family members ( fig .
mutations of p - loop residues q40 and s41 selectively impair stimulated gtp hydrolysis without significantly altering basal turnover ( fig .
mutants of q40 produce the strongest defects , reducing the catalytic enhancement by ~80-fold , almost to the level of basal activity . as predicted from the structure
none of these substitutions affects dynamin s capacity for self - assembly ( supplementary fig .
4 ) , which is to be expected as self - assembly is nucleotide - independent4 .
dynamin is thought to play a dual role in clathrin - mediated endocytosis , such that basal activity is necessary for early endocytic events and assembly - stimulated activity is required in later stages for membrane fission1,17,18,31 .
the identification of mutations that selectively impair assembly - stimulated but not basal gtpase activity allowed us to establish directly the requirement for assembly - stimulated gtpase activity in membrane fission in vivo . for this we used an assay that measures late events in clathrin - mediated endocytosis : the internalization of transferrin conjugated to biotin via a cleavable disulfide bond ( bss - tfn ) into sealed vesicles that are inaccessible to a small membrane impermeant reducing agent ( mesna ) .
4d ) . importantly , as in dynamin knock - out cells32 , fluid phase uptake is not affected ( fig .
the ngtpase , cgtpase , and cged termini form the bundle signaling element ( bse ) , a structure capable of modulating dynamin function in vitro and in vivo19 . as predicted1921
, this element adopts a three - helix bundle configuration that buries an extensive , highly conserved hydrophobic surface ( fig .
5a ) . the bse does not participate in gg dimerization and instead flanks the gtpase core of each gg monomer , protruding in opposite directions from the dimer axis .
structural comparison with the g domain from rat dynamin shows that the bse can pivot as a rigid body around a conserved proline residue ( p294 ) that kinks the cgtpase helix ( fig .
the inter - helix angle between the cgtpase segments on either side of p294 differs significantly in the two gg monomers of both the long ( 68.8 vs. 53.4 ) and short ( 70.4 vs. 59.0 ) axis crystal forms .
thus , while the g domains obey a non - crystallographic two fold symmetry strictly , the bses do so only approximately .
this asymmetry indicates that the link between the g domain and the bse is inherently flexible and susceptible to crystal - packing forces ( supplementary fig .
5a ) . however , this flexibility is limited since the proline at the pivot point does not allow free variations of the relevant main chain dihedral angles .
conformational flexibility in this region has also been suggested by structures of the distantly related bacterial dynamin - like protein ( bdlp)33 .
the functional significance of these observed variations is not yet known , though they may play a role in the conformational coupling of dynamin s gtpase and ph domains10,19,34 .
significantly , in both crystal forms , the bse of one monomer is oriented nearly perpendicular to its partner in the other monomer ( fig .
5b , 5c ) . assuming that the connections between the bse and the middle / ged stalk in full - length dynamin have at least some degree of rigidity
, we would anticipate that the stalks protruding from the two monomers would also adopt a nearly perpendicular orientation .
this orientation is incompatible with previous models for the assembled dynamin polymer where the g domains of adjacent dynamin subunits are positioned with the ngtpase and cgtpase helices perpendicular to the membrane surface ( supplementary fig .
6a ) and the stalks are assumed to extend toward the ph domains in a uniform , parallel array12,13,35 .
subsequent transition - state dimerization in this arrangement would require a significant rotation of the individual g domains relative to one another to achieve the orientation observed in the gg dimer ( supplementary fig .
this in turn would cause subunits in adjacent rungs of the polymer to rotate relative to each other ( fig .
our data establishes that g domain dimerization is an integral part of dynamin s assembly - stimulated gtpase activity .
dimerization stabilizes the conformations of the flexible switch regions and precipitates the dramatic enhancement of dynamin s basal activity by optimally positioning components of the catalytic machinery .
this machinery , which includes q40 , s41 and d180 , is absolutely conserved among classical dynamins but is absent in other large gtpases such as hgbp1 and bdlp ( fig .
4a ) . though these proteins share some common functional characteristics with dynamins29,33 , their catalytic machinery and mechanism of hydrolysis are distinctly different .
we predict that g domain dimerization occurs between two dynamin tetramers and not between subunits within a tetramer ( fig .
our gg dimer structure therefore reflects , at a minimum , the formation of a transition state - dependent dynamin octamer mediated by the association of g domains from two different tetramers ( fig .
, higher - ordered assemblies would be expected as each tetramer contains four independent g domains .
incubation of full - length dynamin with transition state mimics has shown this to be the case in vitro36 , producing rings and spirals under physiological salt conditions in the absence of a lipid scaffold . in vivo
collars at the necks of deeply invaginated clathrin - coated pits to mediate membrane fission .
cryo - em reconstructions of assembled dynamin in the nucleotide - free13 and gmppcp - bound12 states have identified global conformational changes that can constrict the underlying membrane but not sever it .
paradoxically , mounting evidence suggests that stimulated gtp hydrolysis during dynamin - catalyzed membrane fission promotes disassembly of the dynamin collar811 .
furthermore , long dynamin assemblies have been shown to inhibit fission8,11 , indicating that this process depends on some dynamin detachment from the membrane surface .
we speculate that the energy needed for this displacement comes from the transition state - dependent dimerization of dynamin s g domains .
given the relative orientation of the bses and the geometrical constraint imposed by g domain dimerization , this would require a rotation and/or displacement of adjacent tetramers leading to the asymmetric weakening of the ph domain - membrane interactions in one , or both , of the associated tetramers ( fig .
subsequent stimulated - hydrolysis would then dissociate the interacting g domains , releasing those dynamin subunits whose contact with the membrane has been weakened .
cycles of gtp binding , g domain dimerization , gtp hydrolysis and disassembly may be required to reach a critical size of the dynamin polymer to promote fission .
alternatively , one might imagine that g domain dimerization could twist and/or tilt adjacent membrane - associated dynamin subunits to generate additional curvature required for membrane fission .
these represent only the simplest models based on our current structural knowledge , and there are clearly other plausible alternatives .
for example , it has also been proposed that gtp hydrolysis drives conformational changes to generate a mechanochemical power stroke that severs the membrane4,3739 .
we can not rule out the possibility that gtp hydrolysis causes additional force - generating conformational changes in dynamin that have yet to be identified .
high - resolution structural studies examining full - length dynamin in different nucleotide states in combination with cryo - em will be necessary to unravel these possibilities .
protein production , mutagenesis and biochemical assays of gg and full length dynamin were performed as previously described19,40 . to isolate the gg dimer , purified gg monomer was incubated with 2 mm gdp , 2 mm alcl3 , and 20 mm naf for 30 minutes at 37c in sec buffer ( 20 mm tris ph 8.0 , 150 mm nacl , 2 mm egta , 4 mm mgcl2 , and 1 mm dtt ) .
the reaction mixture was then injected onto a superdex 75 hr 10/30 column ( ge healthcare ) to isolate dimeric species .
the gg dimer was crystallized by hanging drop vapor diffusion in 0.1 m tris ph 8.5 , 25% peg 3350 , 200 mm nacl , and 2535% naf using a drop size of 210 ml and a reservoir volume of 750 l .
crystals were frozen in liquid propane prior to data collection and required no additional cryo - protectant .
two orthorhombic crystal forms were obtained ( supplementary table 1 ) that differed mainly in the length of their c axis : 175.7 vs. 181.5 , denoted " short axis " and " long axis " forms respectively .
the long axis crystal form was solved with single isomorphous replacement with anomalous scattering ( siras ) using semet gg crystals .
the short axis crystal form was solved by molecular replacement using the refined long axis structure as a search model .
| ### Summary:
: dynamin is an atypical gtpase that catalyzes membrane fission during clathrin - mediated endocytosis
. the mechanisms of dynamin s basal and assembly - stimulated gtp hydrolysis are unknown , though both are indirectly influenced by the gtpase effector domain ( ged ) . here
we present the 2.0 resolution crystal structure of a minimal gtpase - ged fusion protein ( gg ) constructed from human dynamin 1 , which has dimerized in the presence of the transition state mimic gdp.alf4. the structure reveals dynamin s catalytic machinery and explains how assembly - stimulated gtp hydrolysis is achieved through g domain dimerization .
a sodium ion present in the active site suggests that dynamin uses a cation to compensate for the developing negative charge in the transition state in the absence of an arginine finger .
structural comparison to the rat dynamin g domain reveals key conformational changes that promote g domain dimerization and stimulated hydrolysis .
the structure of the gg dimer provides new insight into the mechanisms underlying dynamin - catalyzed membrane fission . |
<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 persistent observation in the current field of human genetics is that single nucleotide polymorphisms ( snps ) identified through genome - wide association studies ( gwas ) only explain a small fraction of the genetic variation of complex human traits ; the so - called missing heritability problem .
several non - mutually exclusive hypotheses such as rare alleles with large effects , and gene - gene and gene - environment interactions ( reviewed by manolio et al . , and gibson ) have been proposed to explain this lack of explained genetic variation , and they may all account in part for the missing heritability . however , most of these hypotheses assume that the genome is read in the same way across all individuals and therefore , the same snp has exactly the same functionality from a person to another person
. this assumption may be not true for the use alternative regulatory elements ( e.g. gene promoters ) .
for example in a gene with multiple promoters some persons would use preferentially a particular promoter , and other subjects would tend to use another promoter of the same gene . under this scenario ,
a particular snp would have functional significance only among those individuals who use the promoter inside which the snp is located .
the observed effect of that snp would be attenuated relative to its actual effect on a phenotypic trait of interest . in the present report
, i explore some of the quantitative consequences of the hypothesis of alternative use of regulatory elements .
let us assume a gene x that controls a continuous phenotypic trait y. expression of the gene x is under the control of m alternative promoters , and different snps may be present inside each promoter ( figure 1 ) .
the model assumes the existence of person - to - person variation in the use of the alternative promoters maybe through the action of epigenetic marks ( e.g. dna methylation ) .
although in the present work the model is restricted to a gene with only two promoters , p1 and p2 , and two snps : g1 ( inside p1 ) and g2 ( inside p2 ) , the results can be easily generalized to a gene with more than two promoters and more than one snp inside each promoter .
the snp g1 has two alleles , a1 with frequency equal to p1 and a2 with frequency equal to p2 .
the allele a1 increases by a units the value of the phenotypic trait y compared to the allele a2 .
the snp g2 has two alleles , b1 with frequency equal to q1 and b2 with frequency equal to q2 .
the allele b1 increases by b units the value of the phenotypic trait y compared to the allele b2 .
each allele will affect the phenotypic trait y only when its corresponding promoter is being used ( i.e. the allele a1 increases the value of y only when the promoter p1 is used , and the allele b1 increases the value of y only when the promoter p2 is used ) .
the promoter p1 is used in a proportion f1 of the chromosomes in the population , and the promoter p2 is used in an proportion f2 of the chromosomes in the population .
chromosomes that use the promoter p1 have an increase of e units of the phenotypic trait y compared to chromosomes that use the promoter p2 .
hardy - weinberg equilibrium is assumed for each snp . since the goal of the present analysis is to show how genetic variability may be hidden due to the use of alternative promoters , in the following results it is assumed that we do not observe
we only observe the genotypes in g1 and g2 as well as the individuals values of the phenotypic trait y. table 1 shows both the unobserved types of chromosomes according to the unobserved promoter use and observed genotypes in the g1 and g2 snps ( upper half of the table , chromosome types h1 through h8 ) .
note that additive effects are measured relative to the chromosome h8 ( p2a2b2 ) that by definition has a value equal to zero for the phenotypic trait y. observed chromosomes based on only the genotypes in the g1 and g2 snps are shown in the bottom half of table 1 ( chromosome types j1 through j4 ) .
chromosome frequencies are shown for four different models of linkage disequilibrium ( ld ) between the g1 and g2 snps .
the most general scenario ( model 1 ) makes no assumption about any particular value of ld ( given by the d coefficient or covariance between the g1 and g2 snps ) .
scenarios portrayed by models 3 and 4 refer to complete ld between the g1 and g2 snps . in model 3 , the a1 and b1 ( and a2 and b2 ) alleles are always present together
( i.e. only unobserved chromosomes p1a1b1 , p1a2b2 , p2a1b1 , and p2a2b2 exist in the population ) . an opposite pattern of complete ld is shown in model 4 , where the a1 and b2 ( and a2 and b1 ) alleles are always transmitted together ( i.e. only unobserved chromosomes p1a1b2 , p1a2b1 , p2a1b2 , and p2a2b1 are present in the population ) .
it must be noticed that observed chromosomes are obtained from the unobserved chromosomes after collapsing over promoters p1 and p2 .
for example the observed j1 chromosome ( a1b1 ) is a mixture of the unobserved h1 ( p1a1b1 ) and h5 ( p2a1b1 ) chromosomes .
phenotypic value of the j1 chromosome is the average of the phenotypic values of the h1 and h5 chromosomes weighted by the f1 and f2 proportions , respectively .
frequency of the j1 chromosome is just the sum of the frequencies of the h1 and h5 chromosomes .
the rest of the observed chromosomes can be obtained in a similar way : j2 = h2 + h6 , j3 = h3 + h7 , and j4 = h4 + h8 .
the mean chromosome value of the phenotypic trait y is equal to
( 1),e(yc)=iphenotype(i)frequency(i)=f1(ap1+e)+f2bq1
where phenotype(i ) and frequency(i ) are the phenotype value and frequency of the i - th chromosome ( either observed or unobserved ) .
variance of the chromosome phenotype values would be equal to
( 2).v(yc)=ifrequency(i)(phenotype(i)e(yc))2 it is noteworthy that the mean of the chromosome phenotype values does not depend on ld and is the same for the actual ( unobserved ) and observed chromosomes .
however , as it will be shown below , the actual variance due to unobserved chromosomes ( i.e. total variance ) will be always greater or equal than the variance due to observed chromosomes .
in other words the variance due to measurable genetic variation ( i.e. g1 and g2 snps ) will fail to explain 100% of the actual variance due to the totality of unobserved chromosomes in the population .
the mean chromosome value of the phenotypic trait y is equal to
( 1),e(yc)=iphenotype(i)frequency(i)=f1(ap1+e)+f2bq1
where phenotype(i ) and frequency(i ) are the phenotype value and frequency of the i - th chromosome ( either observed or unobserved ) .
variance of the chromosome phenotype values would be equal to
( 2).v(yc)=ifrequency(i)(phenotype(i)e(yc))2 it is noteworthy that the mean of the chromosome phenotype values does not depend on ld and is the same for the actual ( unobserved ) and observed chromosomes . however , as it will be shown below
, the actual variance due to unobserved chromosomes ( i.e. total variance ) will be always greater or equal than the variance due to observed chromosomes .
in other words the variance due to measurable genetic variation ( i.e. g1 and g2 snps ) will fail to explain 100% of the actual variance due to the totality of unobserved chromosomes in the population .
let us define k as the ratio of the variance due to observed chromosomes to the total variance due to unobserved chromosomes .
figure 2 shows k under three different particular scenarios : 1 ) no ld between the g1 and g2 snps , 2 ) positive ld between the g1 and g2 snps ( i.e. a1 and b1 alleles tend to be transmitted together ) , and 3 ) negative ld between the g1 and g2 snps ( i.e. a1 and b2 alleles tend to be transmitted together ) .
figure 2a shows k under linkage equilibrium between the g1 and g2 snps ( model 2 in table 1 ) for different epigenetic effects and proportion of chromosomes using the promoter p1 .
the additive effects of the a1 and b1 alleles were assumed to be equal to 5 units of the continuous phenotypic trait ( a = b = 5 units ) .
the epigenetic effect was allowed to take four different values : e = 0 , 5 , 10 , and 20 units of the phenotypic trait .
it is clear that k 1 , and the higher the epigenetic effect the lower the k ratio ( i.e. the observed chromosomes explain less of the total variance due to the actual unobserved chromosomes ) . even in absence of any epigenetic effect ( i.e. e = 0
meaning that the p1 and p2 promoters have the same baseline level of the phenotypic trait y ) the observed chromosomes do not explain the totality of the variance due to unobserved chromosomes .
the only instances when k = 1 are when only one promoter is used in the population ( i.e. f1 = 1 , use of promoter p1 is fixed ; or f1 = 0 , use of promoter p2 is fixed ) .
figure 2b shows k under positive ld between the g1 and g2 snps ( i.e. the a1 and b1 alleles tend to be transmitted together in the same chromosome ) for different r values ( squared correlation between the g1 and g2 snps ) and proportion of chromosomes using the promoter p1 .
the additive effects of the a1 and b1 alleles as well as the epigenetic effect were kept constant and equal to 5 units of the phenotypic trait ( a = b = e = 5 units ) . for this scenario
k 1 too , and it is noteworthy that the stronger the ld between both snps ( i.e. the higher r ) the more the observed chromosomes would explain the total variance . when r = 1.0 ( complete positive ld as shown in model 3 of table 1 ) reduction of k is attenuated in comparison to the case of linkage equilibrium ( r = 0.0 ) .
figure 2c shows k under negative ld between the g1 and g2 snps ( i.e. the a1 and b2 alleles tend to be transmitted together in the same chromosome ) for different r values and proportion of chromosomes using the promoter p1 .
the additive effects of the a1 and b1 alleles as well as the epigenetic effect were kept constant and equal to 5 units of the phenotypic trait ( a = b = e = 5 units ) . similar to the previous two scenarios we have that k
1 however , in presence of negative ld the higher r the lower the variance that is explained by the observed chromosomes . maximum reduction of that k is observed when r = 1.0 ( complete negative ld as shown in model 4 of table 1 ) .
only the haplotypes a1b2 and a2b1 are observed in the presence of complete negative ld , and as figure 2c shows the variance due to the observed chromosomes can completely disappear ( k = 0 ) .
a simple calculation shows that k vanishes when the proportion of chromosomes using the p1 promoter is equal to f1 = b/(a + b ) .
k will disappear at f1 = 0.5 when both a1 and b1 alleles have the same additive effect ( a = b ) ; at f1 < 0.5 when the a1 allele has a higher additive effect than allele b1 ( a > b ) ; and at f1 > 0.5 when the a1 allele has a lower additive effect that allele b1 ( a < b ) .
figure 2a shows k under linkage equilibrium between the g1 and g2 snps ( model 2 in table 1 ) for different epigenetic effects and proportion of chromosomes using the promoter p1 .
the additive effects of the a1 and b1 alleles were assumed to be equal to 5 units of the continuous phenotypic trait ( a = b = 5 units ) .
the epigenetic effect was allowed to take four different values : e = 0 , 5 , 10 , and 20 units of the phenotypic trait .
it is clear that k 1 , and the higher the epigenetic effect the lower the k ratio ( i.e. the observed chromosomes explain less of the total variance due to the actual unobserved chromosomes ) . even in absence of any epigenetic effect ( i.e. e = 0 meaning that the p1 and p2 promoters have the same baseline level of the phenotypic trait y ) the observed chromosomes do not explain the totality of the variance due to unobserved chromosomes .
the only instances when k = 1 are when only one promoter is used in the population ( i.e. f1 = 1 , use of promoter p1 is fixed ; or f1 = 0 , use of promoter p2 is fixed ) .
figure 2b shows k under positive ld between the g1 and g2 snps ( i.e. the a1 and b1 alleles tend to be transmitted together in the same chromosome ) for different r values ( squared correlation between the g1 and g2 snps ) and proportion of chromosomes using the promoter p1 .
the additive effects of the a1 and b1 alleles as well as the epigenetic effect were kept constant and equal to 5 units of the phenotypic trait ( a = b = e = 5 units ) . for this scenario
k 1 too , and it is noteworthy that the stronger the ld between both snps ( i.e. the higher r ) the more the observed chromosomes would explain the total variance . when r = 1.0 ( complete positive ld as shown in model 3 of table 1 ) reduction of k is attenuated in comparison to the case of linkage equilibrium ( r = 0.0 ) .
figure 2c shows k under negative ld between the g1 and g2 snps ( i.e. the a1 and b2 alleles tend to be transmitted together in the same chromosome ) for different r values and proportion of chromosomes using the promoter p1 .
the additive effects of the a1 and b1 alleles as well as the epigenetic effect were kept constant and equal to 5 units of the phenotypic trait ( a = b = e = 5 units ) . similar to the previous two scenarios we have that k
1 however , in presence of negative ld the higher r the lower the variance that is explained by the observed chromosomes . maximum reduction of that k is observed when r = 1.0 ( complete negative ld as shown in model 4 of table 1 ) . only the haplotypes a1b2 and a2b1 are observed in the presence of complete negative ld , and as figure 2c shows the variance due to the observed chromosomes can completely disappear ( k = 0 ) .
a simple calculation shows that k vanishes when the proportion of chromosomes using the p1 promoter is equal to f1 = b/(a + b ) .
k will disappear at f1 = 0.5 when both a1 and b1 alleles have the same additive effect ( a = b ) ; at f1 < 0.5 when the a1 allele has a higher additive effect than allele b1 ( a > b ) ; and at f1 > 0.5 when the a1 allele has a lower additive effect that allele b1 ( a < b ) .
the current model offers a potential mechanism to explain in part why genetic variants discovered so far do not explain much of the expected genetic variability .
although part of the unexplained variability may be due to rare genetic polymorphisms still to be found , the model predicts that person - to - person variation in the use of alternative promoters would reduce the observed genetic variance of a genetic system .
thus , even a complete knowledge of all the genetic variants involved in a particular phenotypic trait would be no enough to explain the whole genetic variance of the trait .
three major factors explain the reduction of the genetic variance according to the model discussed in the present work .
first , the observed additive effects of the snps inside each of the alternative promoters is attenuated in comparison to their actual effects .
for example , because the allele a1 of the g1 snp exerts its effect only when the promoter p1 is being used , its observed additive effect would be reduced by a factor equal to f1 relative to its actual effect .
the same situation applies for the b1 allele of the g2 snp whose observed additive effect would be attenuated by a factor equal to f2 .
second , because the use of alternative promoters is not being measured ( e.g. in current genetic epidemiology studies such scenario is not even considered as a possibility ) the dimensionality of the observed data would be always lower than the actual dimensionality of the population data
. the number of observed chromosomes will be less than the number of actual chromosomes in the population .
third , different promoters may have different baseline levels of the phenotypic trait under study further reducing the proportion of the actual variance that is due to measured genetic polymorphisms .
recent published evidence supports the proposed hypothesis of person - to - person variation in the use of alternative promoters .
reported the presence of high inter - individual variability in the methylation patterns of alternative promoters of the glucocorticoid receptor ( nr3c1 ) gene in twenty - six healthy subjects , suggesting person - to - person variation in epigenetic regulatory mechanisms . a small study that measured promoter activity of the aromatase ( cyp19a1 ) gene in skin fibroblasts from 4 normal volunteers found that one subject showed increased activity of the promoters i.3 and ii in response to camp , in contrast to the other 3 subjects who expressed the camp - unresponsive promoter i.4 . in non - malignant lung tissue from 15 patients with non - small cell lung cancer , two cases used mostly promoters i.3 and ii of the cyp19a1 gene and the rest of patients used the promoter i.4 .
it is noteworthy that may even exist ethnic differences in the use of alternative promoters .
a recent study in 101 women with uterine leiomyoma ( 31 african american , 34 white american , and 36 japanese women ) reported that leiomyoma tissue from african american women expressed the promoter ii in higher proportion compared to japanese women .
at last , the cd36 gene showed inter - individual variability in the use of four out of five alternative promoters in cultured monocytes from 10 subjects .
the present results , published evidence about variability in the use of alternative promoters , and the fact that more than half of human genes have alternative promoters , with a mean of 3.1 promoters per gene stress the need to carry out extensive studies in human populations to determine and quantify inter - individual variation in the use of alternative promoters . to date there are few approaches to assess the use of alternative promoters in a genome - wide scale .
singer et al . developed a promoter tiling array that can identify about 35,000 alternative promoters from almost 7,000 human genes , and jacox et al .
described a computational approach to determine alternative promoter usage in nearly 1,500 genes using the affymetrix exon 1.0 array .
although those microarrays only interrogates a subset of genes in the genome ( i.e. those genes with known alternative promoters ) they would provide enough data to test the proposed hypothesis in a genome - wide scale .
a comprehensive assessment should ideally measure person - to - person variation across different types of tissue .
the present model can be easily extended to include cases of genes with more than two promoters and more than one snp in each of the promoters . in a gene with multiple promoters , the observed additive effect of a particular snp
would be reduced by a factor equal to the proportion of chromosomes in the population using the promoter in which the snp is located .
the model may also be used for other types of alternative regulatory elements such as multiple enhancers affecting gene expression ; the so - called shadow enhancers .
a limitation of the presented model is that depends on the knowledge about alternative promoters or regulatory elements in general .
more experimental work such as chromatin immunoprecipitation ( chip)-chip assays validated with transgenic models is needed to identify new regulatory elements . in summary
, the present report shows that in presence of inter - individual variation in the use of alternative promoters the observable effects of genetic variants will be lower than their actual effects .
the proposed model may explain in part why gwas - identified variants are in most part poor predictors of human complex traits .
future studies are needed to determine and quantify the person - to - person variability in the use of alternative promoters as well as to identify new regulatory elements in the human genome . | ### Summary:
: genome - wide association studies ( gwas ) have identified a multitude of single nucleotide polymorphisms ( snps ) associated with a wide spectrum of human phenotypic traits .
however , the snps identified so far do not explain much of the expected genetic variation and they are poor predictors of the occurrence of disease .
i recently advanced the hypothesis that there is person - to - person variation in the use of alternative regulatory elements ( e.g. gene promoters ) and this new source of variation may explain in part the low genetic variation accounted for known genetic variants . in the present report a simple mathematical model is developed to explore the biologic consequences of the proposed hypothesis .
the model predicts that in presence of person - to - person variation in the use of alternative promoters the observable effects of genetic variants located inside promoters will be smaller than their actual effects . as a consequence , genetic variation due to
those observed polymorphisms will be reduced .
the present report suggests new paths of research to elucidate the genetic basis of human complex traits . |
<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:
: for many years , removable complete dentures have represented the main solution for restoration of fully edentulous patients [ 13 ] . although many edentulous patients are satisfied with their complete dentures , some encounter problems with this design , including bone resorption of residual ridges over time and lack of stability and retention , with decreased chewing ability [ 13 ]
. this decreased masticatory efficiency can affect overall nutritional intake , comfort , and self - confidence ; these limitations often cause social and psychological disabilities , and are associated with reduced quality of life [ 13 ] . nowadays
, these problems can be successfully addressed with the placement of endosseous dental implants in the edentulous jaws , to retain overdentures ( ods ) .
the benefits of an implant - supported od include increased stability and retention , improvement in chewing ability , and comfort , resulting in higher patient satisfaction and oral health - related quality of life [ 13 ] .
although several studies and systematic reviews have dealt with implant - supported mandibular ods , reporting excellent long - term outcomes [ 46 ] , only a few studies reported on mid- and long - term results with implant - supported maxillary ods [ 710 ] ; in addition , less favorable mid - term and long - term implant survival / success rates have been reported for maxillary implants supporting ods [ 7 , 1116 ] .
these less favourable outcomes have been associated with bone quality and volume that are often more compromised in maxillary than in mandibular sites [ 1116 ] ; however , several factors such as the type , number , and position of the fixtures and the loading conditions may influence the treatment outcomes of implant - supported maxillary ods [ 6 , 7 , 1118 ] . a distinction has been introduced between planned and unplanned maxillary ods , and better outcomes have been found for planned cases [ 8 , 19 ] .
a planned od is the result of a sophisticated treatment planning , including an accurate preoperative radiographical assessment of the edentulous ridges , by means of cone beam computed tomography ( cbct ) scan and three - dimensional ( 3d ) reconstruction software , and the use of predefined operative criteria such as a minimum number of implants with sufficient length / diameter , inserted with the correct position / inclination and splinted with a rigid bar [ 8 , 1719 ] . in recent years
, direct metal laser sintering ( dmls ) has opened new frontiers in biomedical applications [ 2023 ] .
dmls is a technology to directly generate physical objects on the basis of 3d computer models
. this system uses precursor powders to build these shapes through a computer - controlled , self - assembly process .
a high - power laser beam is directed on a metal powder bed and programmed to fuse particles according to a computer - controlled file , generating a thin metal layer ; apposition and fusion of subsequent layers give shape to a desired 3d form , with minimal postprocessing requirements [ 20 , 2325 ] . in the last few years
, the advancements in dmls have allowed the fabrication of dental implants made of ti and ti - based alloys [ 2325 ] .
the chemical and mechanical properties of ti dental implants fabricated with the dmls technique have been investigated [ 20 , 2224 ] .
different in vitro studies with cultures of human osteoblasts [ 20 , 25 ] and mesenchymal stem cells have analyzed the biological response to dmls implant surfaces , such as several in vivo histologic / histomorphometric studies in animals [ 21 , 2729 ] and humans [ 3034 ] .
even though by now the concept of dmls for implant manufacturing is well accepted , there is still limited clinical data in dental literature [ 3541 ] ; in addition , the only available prospective clinical studies are based on a small number of patient with a short follow - up [ 3537 ] .
the aim of the present 3-year prospective clinical study was to evaluate implant survival , complications , and peri - implant marginal bone loss of dmls implants used to support bar - retained maxillary ods .
between january 2009 and march 2011 , all patients referred to the dental clinic of the university of varese , italy , and to a single private practice ( gravedona , como , italy ) were considered for inclusion in this prospective clinical study .
inclusion criteria were as follows : total edentulism in the maxilla , for a period of at least 3 months;functional problems with the conventional complete maxillary denture ( lack of stability and/or discomfort);sufficient maxillary bone volume to place implants at least 3.3 mm in diameter and 8.0 mm in length .
total edentulism in the maxilla , for a period of at least 3 months ; functional problems with the conventional complete maxillary denture ( lack of stability and/or discomfort ) ; sufficient maxillary bone volume to place implants at least 3.3 mm in diameter and 8.0 mm in length .
exclusion criteria were as follows : need for bone augmentation procedures with autogenous bone and/or bone substitutes prior to implant insertion;uncontrolled diabetes mellitus;immunocompromised status;radiotherapy in the maxillofacial region;chemotherapy;treatment with amino - bisphosphonates .
need for bone augmentation procedures with autogenous bone and/or bone substitutes prior to implant insertion ; uncontrolled diabetes mellitus ; immunocompromised status ; radiotherapy in the maxillofacial region ; treatment with amino - bisphosphonates .
smoking was not considered exclusion criteria for this study ; however , patients were advised that smoking is associated with an increased risk of implant failure .
all participants received detailed explanations about the planned treatment and its potential risks and complications and signed a written informed consent form prior to being enrolled in the study .
the study was approved by the local ethical committee , at the university of varese , italy , and was conducted in accordance with the principles outlined in the declaration of helsinki on clinical research involving human subjects , 1975 , as revised in 2002 .
the implants were manufactured from titanium alloy ( ti-6al-4v ) with a dmls technique ( tixos , leader implants , milan , italy ) .
the dmls implants were made of master alloy powder with a particle size of 2545 micrometers as the basic material .
processing was carried out in an argon atmosphere using a powerful yb ( ytterbium ) fiber laser system ( eosint 270 , eos gmbh , munich , germany ) with the capacity to build a volume up to 250 250 215 mm using a wavelength of 1,054 nanometers with a continuous power of 200 w at a scanning rate of 7 m / s .
the size of the laser spot was 0.1 mm . to remove residual particles from the manufacturing process ,
the sample was sonicated for 5 min in distilled water at 25c , immersed in naoh ( 20
g / l ) at 80c for 30 min , and then further sonicated for 5 min in distilled water .
surface cleaning was completed by immersion of the samples in a mixture of 50% oxalic acid and 50% maleic acid at 80c for 45 min , followed by washing for 5 min in distilled water in a sonic bath .
the direct laser preparation provided an implant surface with a roughness that had an ra value of 66.8 , rq value of 77.55 , and rz value of 358.3 micrometers , respectively .
the implants for this study featured an external hexagon connection ( figure 1 ) and were available in lengths of 8.0 , 10.0 , 11.5 , and 13 mm ; the available diameters were 3.3 , 3.75 , and 4.5 mm
. a complete examination of the oral hard and soft tissues was carried out for each patient .
preoperative workups included an assessment of the edentulous ridges using casts and diagnostic wax - up .
cbct datasets were eventually transferred to specific implant navigation software ( mimics , materialise , leuven , belgium ) to perform a 3d reconstruction of the upper jaws . with this navigation software it was possible to correctly assess the width of each implant site and the thickness and the density of the cortical plates and the cancellous bone , as well as the ridge angulations ( figure 2 ) . the same experienced surgeon ( c.m . ) and prosthodontist ( f.m . ) performed all the surgical and prosthetic procedure , respectively , in the two clinical centers .
local anesthesia was obtained by infiltrating articaine 4% containing 1 : 100 adrenaline ( ubistesin , 3mespe , st .
an extended crestal incision was made , with or without releasing incisions , and full - thickness flaps were elevated exposing the alveolar ridge .
the preparation of implant sites was carried out with spiral drills of increasing diameter ( 2.0 and 2.3 mm , to place an implant with 3.3 mm diameter ; 2.0 , 2.6 , and 2.8 mm , to place an implant with 3.75 mm diameter ; 2.0 , 2.6 , and 3.2 mm , to place an implant with 4.5 mm diameter ) under constant irrigation .
the flaps were repositioned to cover the implants completely and were secured in position by interrupted sutures ; after that , the patients ' complete dentures were relined with a soft tissue conditioner ( soft - liner , gc corporation , tokyo , japan ) and used as temporary prostheses .
all patients received oral antibiotics , amoxicillin + clavulanic acid 2 g each day for 6 days ( augmentin , glaxosmithkline beecham , brentford , uk ) .
postoperative pain was controlled by administering 100 mg nimesulide ( aulin , roche pharmaceutical , basel , switzerland ) every 12 h for 2 days , and detailed instructions about oral hygiene were given , with mouth rinses with 0.12% chlorhexidine ( chlorhexidine , oral b , boston , ma , usa ) administered for 7 days .
after this undisturbed healing period , second - stage surgery was conducted to gain access to the underlying implants and healing abutments were placed . a mesiodistal crestal incision , limited to the implant sites , was made and the ridge mucosa was elevated to uncover the implants ;
after that , the complete provisional dentures were discharged abundantly around the healing abutments , seated in mouth , and another partial relining with a tissue conditioner was performed .
two weeks later , the healing abutments were removed and pick - up impression posts were placed at the implant level . the final implant impression was made with generic trays using polyvinylsiloxane ( aquasil monophase , dentsply international , york , pa , usa ) . from this impression ,
a master cast was poured , and a bar was fabricated . for all patients , the splinting suprastructures for the implants consisted of a rigid cobalt - chrome bar , without extensions .
each bar was supported by four implants and presented four boxes for insertion of precision attachments .
after the fabrication of the bar , the implants were elongated with prefabricated titanium abutments , to the top of which titanium copings were screwed .
all ods had a horseshoe design and were fabricated with acrylic resin with a metal framework .
retention of the superstructure was obtained from four prefabricated precision attachments , consisting of nitrided titanium balls ( pivots , rhein 83 srl , bologna , italy ) cemented in the boxes of the bar with zinc - phosphate cement ( harvard , richter & hoffmann gmbh , hoppegarten , germany ) ( figure 3 ) .
all ods were carefully evaluated for proper occlusion : protrusion and laterotrusion were assessed on the articulator and intraorally , to secure a balanced occlusion in centric relation without anterior tooth contact . after the delivery of the od , all patients
were included in a maintenance program , which comprised professional oral hygiene every 6 months . during each follow - up visit , a clinical assessment of implants , peri - implant tissues , and prostheses
was conducted by a periodontist and a prosthodontist neither of whom were directly involved in the treatment of these patients .
the conditions for which implant removal could be indicated included implant mobility due to failure of osseointegration , peri - implant infection with pain / suppuration , progressive marginal bone loss due to mechanical overload , and implant body fracture .
( before the abutment connection ) or late ( after the abutment connection ) implant failures;biological complications , including pain or swelling after surgery , soft tissue inflammation , and peri - implant infection with fistula formation , pain , suppuration , or exudation .
the threshold of peri - implantitis was indicated by a probing pocket depth 6 mm and bleeding on probing or pus secretion;prosthetic complications , such as mechanical complications related to implant components ( loosening or fracture of abutment ) , and technical complications including issues related to anchorage structure ( broken bars , or loose , lost , or broken attachments ) or prostheses ( repairs of fractured prostheses or overdenture teeth ) .
static and dynamic occlusions were evaluated using standard occluding papers ( bausch articulating paper , bausch inc , nashua , nh , usa);peri - implant marginal bone loss .
intraoral periapical radiographs were taken of each implant , using a rinn alignment system ( rinn , dentsply , elgin , il , usa ) with a rigid film - object - x - ray source coupled to a beam - aiming device in order to achieve reproducible exposure geometry .
radiographs were taken at the baseline ( immediately after implant insertion ) and at each annual follow - up session : customised positioners were used to help the correct repositioning of the radiographic template .
changes in peri - implant marginal bone level , as modifications in the distance from the implant shoulder to the first visible bone - to - implant contact ( dib ) , were measured on periapical radiographs which were taken immediately after installation and at the 1- , 2- , and 3-year follow - up examinations .
the dib was measured in mm , at the mesial and distal implant side of each implant , with the aid of an ocular grid . in order to correct for dimensional distortion
, the apparent dimension of each implant was measured on the radiograph and then compared with the real implant length ; mean values between the mesial and the distal measures were obtained for each implant .
the conditions for which implant removal could be indicated included implant mobility due to failure of osseointegration , peri - implant infection with pain / suppuration , progressive marginal bone loss due to mechanical overload , and implant body fracture .
( before the abutment connection ) or late ( after the abutment connection ) implant failures ; biological complications , including pain or swelling after surgery , soft tissue inflammation , and peri - implant infection with fistula formation , pain , suppuration , or exudation .
the threshold of peri - implantitis was indicated by a probing pocket depth 6 mm and bleeding on probing or pus secretion ; prosthetic complications , such as mechanical complications related to implant components ( loosening or fracture of abutment ) , and technical complications including issues related to anchorage structure ( broken bars , or loose , lost , or broken attachments ) or prostheses ( repairs of fractured prostheses or overdenture teeth ) .
static and dynamic occlusions were evaluated using standard occluding papers ( bausch articulating paper , bausch inc , nashua , nh , usa ) ; peri - implant marginal bone loss .
intraoral periapical radiographs were taken of each implant , using a rinn alignment system ( rinn , dentsply , elgin , il , usa ) with a rigid film - object - x - ray source coupled to a beam - aiming device in order to achieve reproducible exposure geometry .
radiographs were taken at the baseline ( immediately after implant insertion ) and at each annual follow - up session : customised positioners were used to help the correct repositioning of the radiographic template .
changes in peri - implant marginal bone level , as modifications in the distance from the implant shoulder to the first visible bone - to - implant contact ( dib ) , were measured on periapical radiographs which were taken immediately after installation and at the 1- , 2- , and 3-year follow - up examinations .
the dib was measured in mm , at the mesial and distal implant side of each implant , with the aid of an ocular grid . in order to correct for dimensional distortion ,
the apparent dimension of each implant was measured on the radiograph and then compared with the real implant length ; mean values between the mesial and the distal measures were obtained for each implant .
data analysis was performed by an independent examiner who was not directly involved in the study .
databases were created with worksheet ( microsoft excel , microsoft corporation , redmond , wa , usa ) and used for the analysis .
descriptive statistics were used for patient demographics ( gender , age , and smoking habit ) and distribution of implants ( position , diameter , and length ) .
absolute and relative frequency distributions were calculated for qualitative variables , such as implant survival / failure and the incidence of biological and prosthetic complications ; means , standard deviations , medians , and confidence intervals ( 95% ) were calculated for quantitative variables , such as peri - implant bone resorption .
implant survival , complications , and peri - implant bone resorption were calculated at the implant and at the patient level .
in total , 35 patients ( 20 males and 15 females ) were considered for inclusion in the present study , over a 2-year period ( january 2009march 2011 ) , in two different clinical centers .
however , 5 patients presented conditions enlisted in the exclusion criteria ( one for immunocompromised status , two for uncontrolled diabetes mellitus , and two for treatment with amino - bisphosphonates ) and could not be included in the study .
consequently , with regard to the aforementioned inclusion and exclusion criteria , only 30 patients ( 18 males and 12 females ; mean age 70 5.5 years , range 6281 , median 69 , ci 95% : 68.171.9 ) were enrolled in the present study . among these patients ,
all patients had conventional complete dentures or implant - supported ods in the mandible . in total
, 120 implants were placed : 60 in the maxillary lateral incisor and 60 in the first premolar area .
only 28 patients ( 112 implants ) were available for the 3-year follow - up control .
in fact , 2 patients ( 8 implants ) could not attend the final follow - up examination ( one patient died ; another had serious health problems , not related to the dental implant therapy , and was hospitalized ) and were considered as dropouts . at the end of the study ,
the overall 3-year implant survival rate was 97.4% ( implant - based ) and 92.9% ( patient - based ) with 109 implants still in function ( figure 5 ) .
these implants were classified as early failures showing clinical mobility due to a lack of osseointegration , without clinical signs of peri - implant infection ; all these failures occurred 4 months after placement , in the first premolar areas , before the connection of the abutment .
another implant failed for extensive bone loss due to recurrent peri - implantitis with pain and suppuration , in a 72-year - old smoking female patient .
this failure occurred in the premolar area after 1 year of function and was consequently classified as late failure .
one 69-year - old nonsmoking female patient ( two implants ) experienced pain and swelling after surgery .
however , the pain was managed by giving anti - inflammatory and analgesic medication , and no further complications were reported for this patient .
two years after placement , one 70-year - old smoking male patient was diagnosed with peri - implantitis : in fact , two implants ( one lateral incisor and one first premolar ) showed suppuration / exudation , bleeding on probing and a probing depth 6 mm .
however , this patient was successfully treated , and no further biological complications were recorded . at the end of the study ,
the incidence of biological complications was 3.5% ( implant - based ) and 7.1% ( patient - based ) .
no mechanical complications related to implant components ( abutment loosening , abutment fractures ) were reported .
the anchorage components used for connecting the bar to the prosthetic framework showed no complications .
all the prosthetic complications were technical in nature and consisted in repairs of fractured prostheses ( acrylic resin was recorded in 2 patients ) or od teeth ( tooth fracture occurred in 3 patients ) . at the end of the study , the incidence of prosthetic complications was 17.8% ( patient - based ) .
the overall radiographic evaluation of the implants showed a mean distance from the implant shoulder to the first visible bone - to - implant contact ( dib ) of 0.39 mm ( 0.25 , median 0.4 , ci 95% : 0.350.43 ) at the 1-year examination .
at the 2-year follow - up control , the bone level of the fixture was situated 0.5 mm ( 0.23 , median 0.55 , ci 95% 0.460.54 ) from the reference point .
finally , at the 3-year examination , the bone level of the fixture was situated 0.62 mm ( 0.28 , median 0.6 , ci 95% 0.570.67 ) from the reference point .
no detrimental effects on marginal bone level were evident between the 1- and 3-year follow - up examinations ( figure 6 ) .
in contrast to the excellent long - term implant survival and success rates shown for implant - supported mandibular ods [ 46 ] , considerably lower survival and success rates have been reported in several studies on maxillary ods [ 7 , 1116 ] . in a retrospective multicenter evaluation of osseointegrated implants supporting ods , engquist et al
. showed a significantly higher loss of fixtures in the maxilla then in the mandible . in another retrospective study on maxillary ods retained by splinted and unsplinted implants , nrhi et al . reported a cumulative survival rate for the implants after 72 months of 90% .
in a retrospective 10-year follow - up study , schwartz - arad et al . reported more complications and implant failures with implant - supported ods in the maxilla ( 83.0% survival ) than in the mandible ( 99.5% survival ) .
similar results were described by visser et al . in a 10-year follow - up study on maxillary ods supported by six endosseous implants and a milled bar mesostructure , with an overall implant survival rate of 86.1% .
more recently , in a 3-year prospective clinical study on 95 patients with 107 ods supported by 360 implants , balaguer et al . found a significantly lower implant survival in the maxilla ( 91.9% ) than in the mandible ( 98.6% ) .
all these results have been related to poor bone quantity / quality or short implants inserted in severely resorbed maxillae [ 7 , 11 , 13 , 16 ] .
poor bone quality , low bone quantity , short implant length with reduced diameter , and poor initial stability are potential problems encountered in the edentulous maxilla and may be responsible for a higher risk of implant loss with maxillary ods [ 7 , 1116 ] . more recently ,
implant placement for maxillary od treatment may have a better outcome than emergency procedures , in which the placement of an insufficient number of fixtures and/or previous failures made a fixed full dental prosthesis an unfeasible option [ 810 , 14 , 19 , 42 ] . in a 5-year follow - up retrospective evaluation based on twenty - seven subjects , of whom 13
were originally planned for od treatment and the other 14 for a fixed prosthesis , widbom et al
. found that fewer implant failures occurred in patients originally planned for od treatment . in a study on
have shown a cumulative 5-year survival rate higher than 98% with four implants placed in the maxillary anterior region anchored on a milled bar . in this work
, the authors have also demonstrated that implant placement in the posterior maxillary region for od anchoring may guarantee an excellent survival rate , even after sinus augmentation . in another planned study , sanna et al
. showed a good outcome with four to six interconnected implants supporting an od in the maxilla , with a cumulative survival rate of the supporting implants of 99.3% after 10 years of function .
these results were confirmed by a recent 5-year prospective clinical study on planned bar - retained ods supported by locking - taper implants , in which satisfactory survival and success rate were achieved both in the mandible ( 98.6% ) and in the maxilla ( 97.4% ) .
these studies demonstrate that the use of a minimum number of four splinted implants of sufficient length and diameter , as well as a careful preoperative planning of implant placement with an accurate study of bone quality and quantity , can result in high survival and success rates of maxillary implants supporting ods [ 8 , 14 , 19 , 42 ] , as confirmed by several reviews [ 18 , 19 ] .
our present 3-year follow - up study on dmls titanium implants supporting bar - retained maxillary ods seems to confirm the results of previous studies on planned ods , with excellent outcomes in terms of implant survival ( 97.4% implant - based ; 92.9% patient - based ) and a low incidence of biological complications ( 3.5% implant - based ; 7.1% patient - based ) .
smoking is a well - documented risk factor for implant failure , and the results of our study seem to confirm this evidence . some prosthetic complications ( 17.8% ) were encountered during this study ; however , all these complications were technical in nature and consisted in acrylic resin or od teeth fractures .
finally , at the 3-year examination , a mean dib of 0.62 mm ( 0.28 ) was found ; minimal changes were observed in the bone level between the 1- and 3-year follow - up examinations , thus in accordance with other recent studies [ 17 , 18 , 44 , 45 ] .
dmls offers the possibility to fabricate titanium dental implants with a bulk , high - density core and a porous , low - density surface , thus combining a solid material with a porous material ( with different percentages of porosity ) in one single structure [ 2024 ] .
the main advantage of the dmls , in fact , is the possibility to fabricate implants with a precisely controlled porous surface [ 20 , 23 , 25 ] .
this layered manufacturing technique provide a complete control over both percentage porosity and the geometry of the interconnected open pore network , so that an intricate , highly porous surface can be prepared directly from metal powders , with minimal postprocessing requirements [ 23 , 25 ] .
this highly porous surface provides ample space for bone regeneration , since bone tissue can grow into the pores to integrate with them : this may improve long - term implant fixation [ 23 , 25 , 2734 ] .
implants , with a gradient of porosity perpendicular to the long axis . with this approach
, the mechanical properties of the titanium implant can be tailored to better match the yield strength and elastic modulus of the host bone , therefore reducing the stress - shielding effect .
this approach introduces the concept of isoelastic dental implants , even if the fatigue properties of highly porous biomaterials may suffer from high levels of porosity [ 20 , 23 , 25 , 2734 ] . finally ,
another important advantage of dmls is to have the unlimited freedom and ability to fabricate highly complex structures : with this layered manufacturing technique , custom - made patient - specific implants can be produced in a cost - time competitive manner [ 3841 ] .
based on these results , and within the limits of this study ( such as the limited number of patients treated and fixtures placed , absence of a control group , and absence of calibration of the evaluators ) , the use of four dmls titanium implants to support bar - retained maxillary ods seems to represent a safe and successful procedure , with excellent 3-year survival rates ( 97.4% implant - based ; 92.9% patient - based ) and a low incidence of biological ( 3.5% implant - based ; 7.1% patient - based ) complications . some prosthetic complications ( 17.8% ) were reported .
no detrimental effects on marginal bone level were evident at the end of the study , with a 3-year mean dib of 0.62 0.28 mm .
further , long - term clinical studies on a larger sample of patients are needed to confirm these results . | ### Summary:
: purpose .
nowadays , the advancements in direct metal laser sintering ( dmls ) technology allow the fabrication of titanium dental implants . the aim of this study was to evaluate implant survival , complications , and peri - implant marginal bone loss of dmls implants used to support bar - retained maxillary overdentures .
materials and methods . over a 2-year period ,
120 implants were placed in the maxilla of 30 patients ( 18 males , 12 females ) to support bar - retained maxillary overdentures ( ods ) .
each od was supported by 4 implants splinted by a rigid cobalt - chrome bar . at each annual follow - up session ,
clinical and radiographic parameters were assessed .
the outcome measures were implant failure , biological and prosthetic complications , and peri - implant marginal bone loss ( distance between the implant shoulder and the first visible bone - to - implant contact , dib ) . results .
the 3-year implant survival rate was 97.4% ( implant - based ) and 92.9% ( patient - based ) .
three implants failed .
the incidence of biological complication was 3.5% ( implant - based ) and 7.1% ( patient - based ) .
the incidence of prosthetic complication was 17.8% ( patient - based ) .
no detrimental effects on marginal bone level were evidenced . conclusions .
the use of 4 dmls titanium implants to support bar - retained maxillary ods seems to represent a safe and successful procedure .
long - term clinical studies on a larger sample of patients are needed to confirm these results . |
<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 amino acid products of endogenous and exogenous protein digestion are degraded by hepatic transamination and oxidative deamination to produce ammonia .
ammonia is then converted to urea via the five enzymes of the urea cycle ( carbamoyl phosphate synthetase , ornithine carbamoyltransferase ( otc ) , argininosuccinic acid synthetase , argininosuccinase , and arginase ) , and excreted by the kidneys ( 1 ) .
any disruption to this nitrogen excretion pathway has the potential to cause hyperammonemia and clinical encephalopathy .
the most common genetic disorder of the urea cycle is a deficiency in otc ( 2 ) .
otc deficiency is heterogeneous in its presentation ( 3 ) , but its symptoms are induced by hyperammonemia caused by the accumulation of precursors of urea , primarily ammonia and glutamine ( 1 ) .
the presentation of severe hyperammonemia caused by otc deficiency varies with the age of the patient . in infants ,
hyperammonemia is associated with lethargy , poor sucking response , vomiting , hypotonia , and seizures ( 4 ) . in adults , although disruption of the urea cycle is usually a result of liver disease ( cirrhosis ) or chemotherapy rather than a genetic defect , partial or late - onset otc deficiency can result from residual enzyme activity associated with peripheral mutations in the otc gene .
its phenotypes are diverse , ranging from severe to apparently asymptomatic ( 5 ) . here
we describe a case of late - onset otc deficiency presenting as severe acute hyperammonemia with coma , and successful treatment with arginine , benzoate and hemodialysis .
a 59-yr - old man was admitted to our hospital because he had exhibited progressive lethargy and confusion since the early morning .
three days prior to presentation , he had eaten a large amount of dog meat at a party , become nauseated , and vomited .
the next day , he had eaten chicken and freshwater snails , had again become nauseated , and developed severe vomiting . on the day of admission , he failed to arise at his normal time and exhibited inappropriate behavior and drowsiness . during his childhood ,
the patient had suffered recurrent abdominal pain and periodic episodes of convulsions , but he had not experienced any seizures in adulthood . on examination ,
the patient was in a semi - coma ; his glasgow coma scale score was 10/15 , and he was disoriented in time , place , and person .
his vital signs were stable , with a blood pressure of 150/80 mmhg , pulse rate of 84/min , respiratory rate of 24/min , and body temperature of 36. laboratory investigations showed that he had hyperammonemia ( 143.8 mm ) , elevated liver enzymes ( alanine aminotransferase , 179 u / l ; aspartate aminotransferase , 91 u / l ) , a total bilirubin level of 1.91 mg / dl , and a blood glucose level of 106 mg / dl .
his blood urea nitrogen and serum creatinine levels were 17.7 mg / dl and 1.01 mg / dl , respectively .
blood analysis revealed mild leukocytosis ( 10.41 10 leukocytes/l ) and a normal hemoglobin level , platelet count , and clotting profile .
serum electrolyte analysis showed mild hypernatremia ( 149 meq sodium / l ) , but serum potassium and chloride levels were within normal range .
further investigations revealed no evidence of gastrointestinal bleeding , and computed tomography ( ct ) and diffusion - weighted magnetic resonance imaging revealed no brain lesions .
although hyperammonemia was suspected as the cause of the patient 's mental changes , there was no evidence of chronic liver disease . despite the administration of a lactulose enema ,
the patient 's serum ammonia level increased to 370 mm and he remained confused , leading us to initiate acute hemodialysis . during the procedure , the patient had a generalized tonic - clonic seizure , for which 1 mg of lorazepam was administered intravenously .
the seizure subsided , but the patient continued to move convulsively , leading to several additional injections of intravenous lorazepam .
a diagnosis of nonconvulsive status epilepticus was made , and the antiepileptic drug levetiracetam was administered .
after the initial session of hemodialysis , the patient 's serum ammonia level had decreased to 170 mm , but it soon rose to 228 mm . plasma and urine amino acid analysis and urine organic acid quantitation were performed . under suspicion of a urea cycle disorder , arginine ( 3 g ) and
sodium benzoate ( 3 g ) were administered via nasogastric tube every 4 - 6 hr .
dextrose solution ( 10% ) was supplied intravenously , and a protein - free formula was supplied via a feeding tube . by the morning of the next day , the patient 's serum ammonia level had decreased to 36 mm . however , because it rose to 107 mm by the afternoon , and the patient was still semi - comatose , hemodialysis was performed one more time . at that time , an electroencephalogram did not show any signs of epileptic discharge .
after the second hemodialysis session , the patient 's serum ammonia level stabilized at less than 30 mm .
a plasma amino acids analysis revealed elevated ornithine ( 196 m ; normal 19 - 81 m ) , decreased citrulline ( 3 m ; normal 19 - 62 m ) , and elevated glutamine and lysine .
urine organic acids analysis revealed highly elevated urinary orotic acid ( 603.5 mg / mg creatinine ) and a mild urinary uracil peak .
he continued to receive sodium benzoate ( 3 g ) and arginine ( 3 g ) three times daily .
the protein - free formula , which was administered continuously , was gradually changed to increase the dietary protein without a significant rise in serum ammonia levels ( fig .
the patient was discharged home after 2 weeks with instructions to continue the medication and formula .
the ornithine carbamoyltransferase ( otc ) gene is encoded on the x chromosome and is expressed in the mitochondrial matrix of the small intestine and liver , where it catalyzes the synthesis of citrulline from carbamoyl phosphate and ornithine ( 1 ) .
otc deficiency has an estimated incidence of 1 in 14,000 and is the only urea cycle disorder that is x - linked ( 1 ) .
recent research on the biochemical and molecular bases of otc deficiency by tuchman et al .
mutations predicted to abolish all enzyme activity were found in the neonatal onset group , while mutations causing partial or varying enzyme deficiency were found in the late onset group ( 7 ) .
patients who were asymptomatic until much later in life were almost always heterozygotes and symptom onset coincided with a precipitating factor such as infection , trauma , sodium valproate , surgery , childbirth , physiological stress or , as in our patient , excess protein intake ( 8 , 9 ) .
a diagnosis of otc deficiency is confirmed when plasma amino acid analysis reveals elevated glutamine and alanine levels and a decreased citrulline level , and orotic acid and uridine are found in the urine ( 1 ) .
the diagnosis can be followed up by liver biopsy to measure otc enzyme activity and mutation analysis .
the measurement of urinary orotidine excretion after allopurinol administration can be used as a simple and reliable test to detect carriers ( 10 ) .
dna analysis of the affected gene is the most reliable method for detecting the carrier state of females and for making a prenatal diagnosis in a family with a positive family history ( 11 ) . in our patient ,
the amino acid analyses of his plasma and urine were consistent with otc deficiency , allowing us to explain the etiology of his hyperammonemia and coma .
although a discussion of his family medical history eventually revealed that four uncles of the patient had died of unknown causes after eating a large amount of meat ( fig .
the therapeutic principles for management of otc deficiency include minimizing endogenous ammonia production , protein catabolism , and nitrogen intake ; administration of urea cycle substrates that are lacking as a consequence of the enzymatic defect ; and administration of compounds that facilitate the removal of ammonia through alternative pathways ( 1 ) . by activating n - acetylglutamate synthetase
benzoate and phenylacetate , by conjugating with glycine and glutamine , respectively , remove excess nitrogen via alternative pathways ( 8) . there are no definite guidelines as to when to initiate dialysis in a patient with hyperammonemia .
however , if the blood ammonia level is more than three to four times the upper limit of normal or is increasing quickly , and/or if the patient is encephalopathic , high - efficiency intermittent hemodialysis should be considered ( 13 ) . for the encephalopathic patient with hyperammonemia ,
rapid initiation of dialysis is critical to minimize the brain damage resulting from continued exposure to elevated blood ammonia .
the rapid removal of ammonia by hemodialysis is not associated with disequilibrium syndrome because ammonia is a gas and not osmotically active ( 14 ) .
after a normal blood ammonia level is achieved , dialysis can be stopped , and the patient can be maintained on urea cycle medications .
this case illustrates the under - recognized fact that late - onset otc deficiency can occur at any age ; our patient was 54 yr old .
his late - onset otc deficiency was successfully treated with hemodialysis and arginine and benzoate administration .
unexplained neurological symptoms in a patient with no history of liver disease should raise the suspicion of a urea cycle disorder , as many cases will respond to treatment with a favorable outcome . | ### Summary:
: ornithine carbamoyltransferase ( otc ) deficiency is a urea cycle disorder that causes the accumulation of ammonia , which can lead to encephalopathy . adults presenting with hyperammonemia who are subsequently diagnosed with urea cycle disorders are rare .
herein , we report a case of a late - onset otc deficient patient who was successfully treated with arginine , benzoate and hemodialysis .
a 59-yr - old man was admitted to our hospital with progressive lethargy and confusion .
although hyperammonemia was suspected as the cause of the patient 's mental changes , there was no evidence of chronic liver disease .
a plasma amino acid and urine organic acid analysis revealed otc deficiency . despite the administration of a lactulose enema , the patient 's serum ammonia level increased and he remained confused , leading us to initiate acute hemodialysis .
after treatment with arginine , sodium benzoate and hemodialysis , the patient 's serum ammonia level stabilized and his mental status returned to normal . |
<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:
: fungal keratitis is a frequent cause of microbial keratitis in india.1
aspergillus and fusarium are two of the most common pathogenic fungi isolated.2
alternaria belongs to group of dematiaceous fungi ( black pigmented molds due to melanin ) and constitutes an uncommon cause of keratitis with challenging management.234 de - domingo - barn et al.1 and zahra et al.3 have reported cases of alternaria keratitis in two patients who underwent penetrating keratoplasty .
a 30-year - old male patient presented with the complaints of decreased vision in both eyes for 25 years . his best corrected visual acuity ( bcva ) was 20/60 , n6 and 20/80 , n10 in the right and left eyes respectively . on examination ,
he had bilateral central , leucomatous , vascularized corneal opacity , which was larger in the left eye [ figure 1a ] as compared with the right eye .
vascularized corneal opacity of left eye patient underwent deep anterior lamellar keratoplasty ( dalk ) in the left eye .
post - operatively , patient was prescribed topical 0.5% moxifloxacin , 0.3% tobramycin , 0.1% dexamethasone and 2% hydroxypropyl methyl - cellulose 6 times / day and 1% atropine once at night .
patient developed a recurrent epithelial defect over the next 3 months with a bcva of 20/60 .
the defect was treated with a bandage contact lens ( bcl).5 at the 3 month follow - up visit , patient presented with reduced vision in the left eye ( bcva 20/200 ) along with redness and pain .
patient was a driver by occupation and resumed his work 2 days prior when he had an episode of dust particles entering into the left eye . on examination , dust particles were present along with an epithelial defect in the graft .
patient was started on topical 0.3% fluconazole , 0.5% moxifloxacin 0.3% tobramycin along with 2% hydroxypropyl methyl - cellulose eye ointment 6 times / day and 1% carboxymethyl - cellulose hourly .
one week later , a large brown pigmented dry lesion was present on the graft [ figure 1b ] . with a working diagnosis of keratitis ,
corneal scrapping was performed , which showed segmented filamentous fungi on 10% potassium hydroxide mount [ figure 2a ] as well as on lactophenol blue stain [ figure 2b ] .
graft showing brown lesion 10% potassium hydroxide mount showing filamentous fungi lactophenol blue stain showing segmented , filamentous fungi culture on sabouraud dextrose agar at 30c yielded colonies of alternaria species within 7 days of incubation [ figure 2c ] .
oral fluconazole ( 150 mg ) twice daily were started in addition to the topical medications .
after removal of the old graft button , four drops of amphotericin b ( 5 /0.1 ml ) were place on descemet 's membrane .
patient was prescribed oral fluconazole 150 mg twice daily , ofloxacin 200 mg twice daily and acetazolamide 250 mg twice daily along with topical 5% natamycin , 0.5% moxifloxacin , 0.3% tobramycin , 0.1% dexamethasone , in addition to 2% hydroxypropyl methyl - cellulose 6 times / day and 1% carboxymethyl - cellulose cmc 8 times / day .
patient improved with complete epithelial healing in 2 weeks and topical 5% natamycin was changed to 1% voriconazole . at 1 month follow - up
, the left eye bcva was 20/60 that remained stable at 11 months follow - up [ figure 2d ] .
alternaria colony on sabouraud dextrose 11 month after repeat deep anterior lamellar keratoplasty , no signs of recurrence in graft
fungal keratitis is a major cause of corneal blindness in developing countries.1 it has been associated with a spectrum of fungal species such as aspergillus , funsarium and candida in addition to rare types such as dematiaceous fungi including alternaria and curvularia.1235 the occurrence of fungal keratitis has been associated with many risk factors such as ocular trauma , diabetes , surgery and use of topical corticosteroids and antibiotics.1 in this case report , the factors which may have predisposed to the development of fungal keratitis include corneal microtrauma in the form of exposure to dust particles , use of topical antibiotics and corticosteroids and bcl .
the dust particles may have been the source of the fungal spores . in the literature ,
alternaria keratitis has been associated with the use of both soft as well as rigid contact lens.67 clinically , the lesion of alternaria keratitis resembles that of a classic filamentary keratitis with the presence of feathery , delicate greyish - white or yellowish white material in the stroma surrounded by infiltration and edema along with satellite lesions . the epithelium may be intact or have a granular , irregular surface .
alternaria , a dematiaceous fungus , may demonstrate macroscopic pigmentation in addition to developing a dense , opaque , greyish - white suppuration in the stroma with minimal associated enlargement and inflammation.18 following repeat dalk , patient was started on oral fluconazole along with topical 0.5% natamycin , which is a broad spectrum anti - fungal agent .
so , once the epithelium had healed completely in 2 weeks , patient was switched from 5% natamaycin to 1% voriconazole , which has been shown to be highly effective for alternaria keratitis.9 voriconazole is a triazole antifungal agent derived from fluconazole .
studies have established voriconazole to be a valuable fungistatic agent against most yeast in addition to many hyaline and dematiaceous filamentous fungi.10 oral fluconazole and 1% voriconazole eye drops were continued for 2 months following repeat dalk .
the case report illustrates the role of newer antifungal agents such as topical voriconazole in combination with oral fluconazole for management of non - healing fungal keratitis .
we recommend a prospective , randomized , comparative long - term study of various antifungal agents to assess their efficacy as well as gauge the risks and benefits associated with each antifungal in addition to formulating a treatment protocol for non - healing fungal keratitis . in conclusion , this case report underlines the importance of keeping alternaria species as differential diagnosis in a case of fungal keratitis .
it also highlights the importance of establishing the final diagnosis of fungal keratitis with corneal scraping for culture studies along with demonstrating the fungal elements on microscopic examination .
use of newer antifungal agents such as voriconazole and fluconazole should be considered for fungal keratitis unresponsive to standard treatment regimes . | ### Summary:
: to describe a case of alternaria keratitis in a 30-year - old male patient who presented with bilateral vascularised central corneal opacity and underwent deep anterior lamellar keratoplasty ( dalk ) in the left eye .
patient was treated for recurrent epithelial defect with a bandage contact lens in the follow - up visits after dalk .
subsequently , patient presented with pigmented fungal keratitis , which on culture examination of the corneal scrapping demonstrated alternaria species .
patient had to undergo a repeat dalk as the keratitis did not resolve with medical therapy alone .
patient did not have a recurrence for 11 months following the regraft .
this case report highlights the importance of considering the alternaria species as a possibile cause of non - resolving fungal keratitis after dalk . |
<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:
: intraductal papillary mucinous neoplasms ( ipmn ) are pancreatic precancerous lesions composed of dilated main and branch ducts and mixed duct type ( main and branch ducts are both involved ) lined by mucin producing atypical epithelium , which usually proliferates in a papillary fashion . based on their increasing architectural and nuclear atypia , ipmn
are divided into four stages : ipmn low - grade dysplasia ( alternatively intraductal papillary mucinous adenoma , ipma ) , ipmn intermediate grade dysplasia ( alternatively borderline ipmn , ipmb ) , and ipmn high - grade dysplasia ( alternatively intraductal papillary mucinous carcinoma , ipmc ) and about 20% to 40% ipmc were invasive ductal carcinoma ( idc ) [ 1 , 2 ] .
moreover , on the basis of the histological and immunohistochemical characteristics , ipmn could be divided into intestinal , pancreatobiliary , oncocytic , and gastric subtypes [ 3 , 4 ] .
ipmn are known to harbor mutations of kras [ 5 , 6 ] , p16 , p53 , gnas , rnf43 , and dpc4/smad4/madh4 , but the prevalence of the mutations is lower than in pancreatic ductal adenocarcinoma ( pdac ) . with development of high - throughput molecular techniques such as gene microarrays ,
lots of differentially expressed genes ( degs ) have been found with ipmn progression , such as brca1 , sox9 , and muc6 . meanwhile
, some cellular signaling pathways were found to be involved in the ipmn carcinogenesis , such as phosphoinositide 3-kinases - protein kinase b / akt pathway , the dna damage checkpoint pathway , inactivation of tumor suppressor pathways , p53 pathway , activation of oncogenic pathways , and k - ras pathway . however , the comprehensive integrated analysis of genes and biological processes and pathways leading to development and progression to malignancy of ipmn were still not clearly demonstrated . in this study , for comprehensive understanding , the mechanism of ipmn , a microarray dataset including normal main pancreatic ductal tissue ( nt ) , ipma , ipmc , and idc originating in ipmn were collected from national center for biotechnology information ( ncbi ) gene expression omnibus ( geo ) .
time - series expression analysis was used to screen the multiclass differentially expressed genes ( degs ) during four stages of carcinogenesis . and
functional enrichment analysis was used to explore the biological processes and pathways related to each cluster .
then , transcription factors ( tfs ) enrichment analysis was used to detect the key tfs in each cluster of degs . at last ,
finally , an overall survey map of functional disorder and corresponding tfs for the progress of the ipmn were established .
we selected the gene expression profile data gse19650 from ncbi geo , executed on affymetrix human genome u133 plus 2.0 array ( platform number gpl570 ) ; the dataset contains 22 samples including 7 normal main pancreatic ducts ( nt ) , 6 ipma , 6 ipmc , and 3 idc originating in ipmn .
firstly , the raw data were normalized by rma ( robust multiarray average ) background subtraction and quantile was normalized using affymetrix expression console software , and noise derived from absent genes , background , and nonspecific hybridizations was removed .
a well - known cancer gene dataset including 547 genes was collected from cancer gene census database . and
the significance of overlap between known cancer genes and degs was calculated using the cumulative hypergeometric function ( p < 0.05 ) ( see details in section 2.4 ) , and calculations were implemented in r statistical package using function phyper ( http://www.r-project.org/ ) .
degs among the four stages of ipmn progression were identified by significance analysis of microarrays ( sam ) algorithm ( multiclass sam , at least one |fold change| 2 , q values < 0.05 ) . then these degs were clustered by k - means clustering .
the functional significance of the degs clusters was investigated by performing functional enrichment and clustering analysis using the database for annotation , visualization and integrated discovery ( david ) .
one of the david 's features is functional annotation cluster in those places similar to go categories , based on the parent / child go term associations and the number of the shared genes , into a functional cluster .
the go cluster enrichment score is based on geometric mean of member 's p values and used to rank their biological significance .
we used this feature to estimate the relationship between the go terms ( biological process of the go database ) and the kegg pathways .
the threshold of enrichment score for enriched clusters was set as 1 artificially . in this study , we downloaded tfs and their regulation genes from transfac database ( release 3.4 ) .
all experimentally verified tfs and their target gene sets were used in this study , containing 106 tfs , 2921 target genes , and 6238 tf - target gene interactions . among the 106 tfs ,
tfs enrichment analysis is a common statistical technique to reveal the significantly changed modules of the target gene sets against the background so as to elucidate the underlying tf regulation mechanisms .
the score of each tf and target gene set was calculated using the cumulative hypergeometric function as follows:(1)p=1i=0x1kimknimn , where m represents the total number of genes tested .
x is the number of the degs in certain cluster that also appeared in certain tf target genes .
the resulting p value ( p < 0.05 ) reflects the probability of extracting up to x of possible k genes in n drawings .
all of the above calculations were implemented in r statistical package using function phyper ( http://www.r-project.org/ ) .
the tissue samples of four stages of ipmn were collected from tianjin third central hospital , including five nt , one ipma , five ipmc , and five idc originating in ipmn .
this study was approved by the experimental and ethics committees of tianjin third central hospital , and written informed consent from each participating subject had been obtained .
three tfs ( esr1 , erg , and fli1 ) enriched in cluster 1 were validated by quantitative ( q ) real - time ( rt ) polymerase chain reaction ( pcr ) assays using these samples .
the qrt - pcr reactions were performed on a roche lightcycler instrument 1.5 , using a lightcycler fast start dna master plus sybr green i kit ( roche cat .
briefly , 15 l reactions : 7.5 l master mix , 0.1 l forward primer and reverse primer , 1 l cdna sample , and 6.3 l ddh2o were prepared .
the rt - pcr program was set to 95c for 5 minutes and then 45 cycles of 95c for 10 seconds , 5560c for 35 seconds , and 72c for 40 seconds .
also , the data were automatically analyzed by the system , and an amplification plot was generated for each cdna sample at the end of each rt - pcr run .
to investigate the gene expression patterns in ipmn progression , multiclass sam algorithm was used to screen the degs among four stages of carcinogenesis , and 2658 degs were identified . then a well - known cancer gene dataset called cancer gene census was used to evaluate the relationship between degs and tumorigenesis .
cancer gene census is an ongoing effort to catalogue those genes for which mutations have been causally implicated in cancer , and many studies used it as a well - known cancer gene dataset [ 21 , 22 ] . particularly , there were 88 degs ( hypergeometric p = 0.0019 ) that overlap with the known cancer genes ( see figure 1 ) , including pdac related genes such as myc , brca1 , and kras [ 2325 ] , which indicates that the degs of this study have close bond with the cancer progression indeed . to thoroughly investigate the genomic expression pattern among four stages of ipmn progression , k - means clustering was used to cluster the degs by expression pattern similarity . as in the results shown in figure 2
c1 contained 992 degs , which was downregulated in ipma stage and then kept low expression level in ipmc and idc stages ; c2 contained 397 degs , which was upregulated in ipma stage and then slightly downregulated during ipmc and idc stages ; c3 contained 476 degs , which was upregulated in ipma stage , slightly downregulated in ipmc stage , and then slightly upregulated in idc stage ; c4 contained 244 degs , which kept low expression level in ipma stage and was upregulated in ipmc stage and then slightly upregulated in idc stage ; c5 contained 97 degs , which was downregulated in ipma stage , slightly upregulated in ipmc stage , and then upregulated in idc stage ; c6 contained 83 degs , which was downregulated in ipma and ipmc stages and then kept low expression level in idc stage ; c7 contained 205 degs , which was continuously upregulated during the three stages of ipmn ; c8 contained 164 degs , which was upregulated in ipma stage and kept high expression level in ipmc stage and was then downregulated in idc stage .
for all these clusters of degs , different clusters were regulated in different cancer stages , which indicates that each cluster may play roles in one or several specific cancer stages .
analysis of degs clusters could help pinpoint potential functional mechanism important for gene expression during ipmn progression .
therefore , david was used to evaluate the biological processes and pathways related to these 8 clusters of degs ( enrichment score > 1 ) .
as shown in figure 3 and supplementary tables in supplementary material available online at http://dx.doi.org/10.1155/2015/197603 , degs in c1 that contains almost half of all degs were enriched in many biological processes , mainly involved in 5 aspects : vasculature development ,
cell migration and locomotion , neuron development differentiation , phosphorylation , and endocytosis ; degs in c2 were enriched in
cation homeostasis , protein localization and transport , and glycosylation ; degs in c3 were enriched in acid biosynthetic process , immune cell differentiation , cytoskeleton organization ,
glycosylation , small molecule catabolic process , and nuclear transport ; degs in c4 were enriched in cell cycle ,
mitosis , dna and chromosome organization , protein ubiquitination , and phosphorylation ; degs in c5 were enriched in cell growth , development , and differentiation , skeletal system development , cell communication ,
blood circulation , and response to nutrient , metal ion ; degs in c6 were enriched in
phosphorylation , proteolysis , cell proliferation , and regulation of binding ; degs in c8 were enriched in
rna splicing , protein localization and transport , and proteolysis .
among these various biological processes , most of them were involved in multiple cancer stages such as phosphorylation ,
glycosylation , and proteolysis ; for comparison , some biological processes played a role in specific cancer stage ; for example , cell cycle and related functions play a main role in c4 , in other words , between ipma and ipmc stage .
the cluster analysis of degs identified groups of genes that exhibit similar expression profiles and thus might be coregulated .
analysis of such coregulated gene sets could help pinpoint potential tfs important for gene expression during cancer progression .
therefore , to gain an initial understanding of the regulatory mechanisms of genes differentially expressed during cancer progression , a total of experimentally validated tfs network data containing 106 tfs , 2921 target genes , and 6238 tf - target gene interactions were gathered from tranfac database .
genes in each cluster were screened for overrepresentation of known tfs ( cumulative hypergeometric ; see section 2 for details ) .
14 tfs which have target genes in these clusters were detected , and tfs enrichment analysis showed that three tfs ( esr1 , erg , and fli1 ) were selectively enriched in cluster 1 ( as shown in table 2 and figure 4 ) , suggesting that these three tfs and their corresponding target genes may play important roles in early stages of ipmn progression , but these three tfs in ipmn progression have not yet received much attention and research .
in addition , the rest of 11 tfs such as samd4 , myc , pparg , and ppara have also been proved to play key roles in various cancer progressions [ 2830 ] .
the qrt - pcr experiments were used to verify the expression of these three tfs in different stages of ipmn . as in the results showed in figure 5 ,
the mrna levels of esr1 , erg , and fli1 were remarkably decreased between nt and ipma ( t - test , p < 0.05 ) and then continuously and slightly decreased during ipmn progression , which confirmed the results of the microarray analysis and tfs enrichment analysis .
these results suggested that these three tfs may play important roles at the beginning of ipmn and still have some effect in the process of ipmn progress to idc .
intraductal papillary mucinous neoplasm ( ipmn ) is a kind of pdac , about 40% of which may develop into idc , and the 5-year survival rate for patients with these lesions varied widely from 0% to 64% in several reported series [ 3234 ] .
the progression could be divided into four stages , ranging from adenoma to invasive carcinoma by neoplasm dysplastic changes .
therefore , revelation of the molecular mechanism of the multistep carcinogenesis process carried out for clinical treatment and diagnosis has an important role in guiding . in this study , for comprehensive investigating of the ipmn progression , a time - series clustering analysis method was performed to analyze the genomic expression patterns of multistages of ipmn ; then functional and tfs enrichment analysis were used to identify the highly related function and molecular mechanism of ipmn progression .
from the results of clustering and functional enrichment analysis of degs , eight clusters of degs with different expression patterns and the corresponding various biological processes and pathways were identified . and
an overall survey map of functional disorder for the progression has been established according to these results .
as figure 6 showed , from nt to ipma stage , many upregulated degs ( degs in c2 , c3 , c7 , and c8 ) were enriched in various biological processes such as phosphorylation ,
cell proliferation , and cytoskeleton organization , and lots of downregulated degs ( degs in c1 , c5 , and c6 ) were enriched in biological processes such as cell communication , migration , locomotion , growth , development , and differentiation and vasculature development .
these biological processes have been proved to have significant relationships with pancreatic cancer progress [ 3537 ] . in accord with the clinical characteristics of ipma ,
these results indicate that , in the early stage ( ipma ) of carcinogenesis , the pancreatic duct cell began proliferation , development , and differentiation and obtained the migration ability by communicating with other cells , transferring the signaling by protein phosphorylation activity .
these molecule changes may lead to dilatation and/or cystic lesion of the pancreatic duct and show low - grade dysplasia .
meanwhile , for supply nutrients to development of dilatation and/or cyst , these processes were accompanied with vasculature development . from ipma to ipmc stage , the up- ( degs in c4 ) and downregulated degs ( degs in c6 ) were enriched in biological processes such as mitosis , cell cycle ,
phosphorylation , and protein ubiquitination , suggesting that the adenoma cell suffers severe cell cycle disorder , accompanied with drastic protein phosphorylation and ubiquitination .
these molecule changes may make cells of dilatation and/or cyst grow up rapidly and show intermediate grade and high - grade dysplasia . from ipmc to idc , the up- ( degs in c5 and c7 ) and downregulated degs ( degs in c8 ) were enriched in biological processes such as cell growth , proliferation , and communication ,
rna splicing , protein localization and transport , and proteolysis .
these processes indicate that , in idc stage , the cancer cell obtained ability of cell growth and proliferation .
moreover , dilatation and/or cyst may obtain invasiveness and become malignant by protein phosphorylation and cell - cell communication . in this stage ,
the gene transcription and protein metabolism increased , invasive cells proliferated enormously , and ipmc developed to idc .
for this survey map , a biological process , phosphorylation , has been found to be involved in all stages , which indicates that this process may play a key role in the whole progression of carcinogenesis and may be a new targeted therapeutic strategy for ipmn .
the cluster analysis of degs identified groups of genes that exhibit similar expression profiles and thus may be coregulated .
analysis of such coregulated gene sets could help pinpoint potential tfs important for gene expression during cancer progression .
therefore , tfs and their corresponding target genes dataset was gathered from transfac database for enrichment analysis .
three tfs ( esr1 , erg , and fli1 ) were detected that not only significantly regulate the degs in cluster 1 , but also have regulatory relationships between each other .
what is more , the results of qrt - pcr experiments validated that these three tfs were remarkably decreased between nt and ipma and then continuously and slightly decreased during ipmn progression .
erg and fli1 genes are closely related members of the erythroblast transformation - specific ( ets ) family of transcription factors , and studies have proved that these two tfs were usually involved in various types of cancer jointly [ 38 , 39 ] . meanwhile , the esr1 , estrogen receptor encoding gene , has been proved to be involved in pathological processes including breast cancer and endometrial cancer .
moreover , most of the regulated genes ( 18/25 ) of these three tfs could be found in pancreatic cancer database .
nevertheless , our study indicates that these three tfs may be the key regulators in early stage of ipmn and are definitely worth further exploration .
in addition , the rest of tfs such as pparg , ppara , smad3 , myc , and stat1 have been proved to be related to cancer progression [ 2830 , 42 ] .
our study provides a comprehensive perspective for the progression of pancreatic carcinogenesis by distinct bioinformatics analysis .
a number of degs clusters and specific biological processes were detected in progression , and then an overall survey map of functional disturbance for the progression has been established .
then , the tfs enrichment analysis and qrt - pcr experiments found that three tfs may be playing key roles in early stages of ipmn progression .
we believe that these results have a certain value in development of ipmn mechanism study and based medicine research . | ### Summary:
: this study has analyzed the gene expression patterns of an ipmn microarray dataset including normal pancreatic ductal tissue ( nt ) , intraductal papillary mucinous adenoma ( ipma ) , intraductal papillary mucinous carcinoma ( ipmc ) , and invasive ductal carcinoma ( idc ) samples . and
eight clusters of differentially expressed genes ( degs ) with similar expression pattern were detected by k - means clustering .
then a survey map of functional disorder in ipmn progression was established by functional enrichment analysis of these clusters .
in addition , transcription factors ( tfs ) enrichment analysis was used to detect the key tfs in each cluster of degs , and three tfs ( fli1 , erg , and esr1 ) were found to significantly regulate degs in cluster 1 , and expression of these three tfs was validated by qrt - pcr .
all these results indicated that these three tfs might play key roles in the early stages of ipmn progression . |
<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 saudi arabia , the basic law of governance states that the state shall look after public health and provide health care for every citizen . accordingly , in 2001 , the ministry of health ( moh ) established the general directorate of patients ' relation to look after patients ' rights and in 2006 was able to publish the first edition of patients ' bill of rights ( pbr ) in saudi arabia , which was endorsed in 2010 by the national society for human rights in saudi arabia . on november 22 , 2011
, the international conference on patients ' rights was organized in saudi arabia . on december 27 , 2011 , a new edition of pbr was published .
this was presented at the national conference on patients ' rights in saudi arabia organized by the moh on april 4 , 2012 .
patients ' rights movement is growing worldwide , making governments and healthcare providers more accountable for the provision of high - quality health services .
a health system that provides treatment and care should adhere to the existing laws and policies to adequately protect patients ' rights and ensure patients ' safety .
it has been suggested that to improve pbr , several courses of action should be taken .
. 's ( 2009 ) study showed that out of 183 students , 71% reported witnessing patient rights abuses and professional lapses , including physical abuse ( 38% ) , verbal abuse ( 37% ) , disrespect for patients ' dignity ( 25% ) , and inadequately informing patients about their treatment ( 25% ) .
alghanim ( 2011 ) found out that more than three - quarters of patients and one - third of primary healthcare ( phc ) providers did not know of the existence of the pbr , and three - quarters of patients and almost half of health providers had very little knowledge of what pbr entailed .
although knowing what pbr entailed is fundamental to an efficient healthcare system , a few studies have been done to assess the knowledge of the details of the pbr .
this study aimed to assess the knowledge of physicians about the substance of the pbr and its implementation .
a cross - sectional study was conducted in a university hospital and affiliated centers and clinics .
all physicians working in the king fahad hospital of university at the time of the study were included in the study .
data was collected using a self - administered questionnaire developed by the researchers based on the pbr document published by the moh , saudi arabia , in 2007 .
the first part of the two - part questionnaire contained questions on demographic data ( age , gender , and nationality ) , medical specialty ( internal medicine , surgery , obstetrics , and gynecology , pediatrics , family medicine , and other medical and surgical specialty ) , years of experience , and level of education / professional status ( interns , both program and service residents , specialist and consultants , both faculty and nonfaculty ) .
the second part was a test of the physician 's knowledge of the substance of the pbr .
a total of 34 items about pbr were included with three possible responses agree , disagree , and do not know .
some space was provided at the end of the questionnaire , for the physician to write down any comments .
for the questions related to knowledge , each correct answer was given a score of 1 and 0 for every incorrect response .
if the knowledge percentage was 75 , then the level of knowledge was categorized as adequate , and inadequate if it was < 75 .
the reliability of the tool was tested using cronbach 's alpha to calculate the overall internal consistency for the entire 34-item scale of the knowledge of physicians on the pbr scale , and the coefficient was 0.72 .
one of them was on the medicolegal committee and the other on the ethics committee .
the questionnaire was piloted on ten participants in another hospital to examine the clarity of the questionnaire .
the study was approved by the local committee of the saudi commission for health specialties for the family medicine training program in the eastern province of saudi arabia and approved by the institutional review board of the university hospital .
the data were entered into ms excel program and cleaned for outliers and entry error .
the cleaned data were imported into statistical software spss version 16.0 ( spss inc . released 2007 .
descriptive analyses included frequency and percentages for categorical variables , and mean and standard deviations for continuous variables .
bivariate analyses were carried out to calculate odds ratio ( or ) for association between sociodemographic variables and the level of knowledge ( adequate / inadequate ) .
a total of 250 questionnaires were distributed to the doctors ; 207 physicians responded giving a response rate of 82.14% .
of those who responded , most of the participants ( 52.7% ) were females , most ( 58.5% ) were aged 25 - 30 years , and were saudis ( 80.2% ) [ table 1 ] . a large proportion of the physicians in the study were residents ( 44.9% ) , followed by interns ( 21.7% ) , consultants ( 18.4% ) , and specialists ( 11.1% ) .
sociodemographic and professional details of the physicians participated in the study ( n=207 ) the highest representations in the sample belonged to medical ( 21.3% ) , surgical ( 18.8 ) , and other specialties ( 21.7 ) .
the smallest numbers were from pediatrics 28 ( 13.5% ) , general practice 19 ( 9.2% ) , emergency medicine 18 ( 8.7% ) , and obstetrics and gynecology 14 ( 6.8% ) .
many physicians ( 45.4% ) had work experience between 1 and 5 years , followed by ( 28% ) having < 1 year experience [ table 1 ] .
patients should know the identity and professional status of the healthcare providers responsible for their treatment had the highest proportion of correct response ( 98.1% ) .
doctors are entitled to withholding any procedures related to a patient 's condition if the patient refuses their choice of treatment was the item with the least correct responses ( 15.5% ) and five other items had correct responses < 50% .
more than two - fifths of the physicians , ( 44.44% ) , had adequate knowledge .
responses to each item of the patient 's bill of rights ( pbr ) questionnaire ( n=207 ) the physicians aged 3140 years had a higher proportion ( 71.9% ) of knowledge than the other age groups which was considerably less ( = 15.44 , p = 0.001 ) .
more than three - fifths of the specialists ( 73.9% ) and consultants ( 68.4% ) had adequate knowledge of pbr compared to other physician categories where the proportion was quite low ( = 16.82 , p = 0.002 ) .
of the physicians who had > 5 years ' work experience , 70.9% had adequate knowledge of pbr compared to the lower proportions of the other groups with work experience ( = 9.974 , p = 0.007 ) .
the results of unadjusted and adjusted logistic regression analyses of physicians ' level of knowledge on pbr are presented in table 3 .
the analyses showed that the physicians in the specialist category were 7.04 times more likely to have adequate knowledge of pbr than the interns ( adjusted odds ratio [ aor ] = 7.04 ; 95% ci : 1.0945.52 ) ( p = 0.040 ) .
the aim of this study was to assess the knowledge of physicians about the substance of the pbr and its implementation .
most of the participants were aged 2530 years ( 58.5% ) , and the majority ( 80.2% ) were saudis .
this implies that saudization policy was being implemented . since the study hospital was a teaching hospital ,
the majority of the physicians in the study were in the residency program ( 44.9% ) and many physicians had work experience between 1 and 5 years ( 45.4% ) .
as expected , there was more representation of those in the medical specialty ( 21.3% ) because it had the highest number of doctors and wide range of fields .
the results are slightly different from the study by alghanim , which reported that 48.8% of phc staff had little or very little knowledge of the details of the bill ( p < 0.001 ) .
the physicians ' response to each item of pbr showed that a majority gave the correct answer to item 2 :
patients should know the identity and professional status of the health care providers responsible for their treatment ( 98.1% ) .
the study by saleh and khereldeen had the same findings that all physicians in both study hospitals indicated that the right to know the name of the attending physician ( 100% ) is considered an actual patient 's right .
item 16 consent must be written in a language can be understood by the patient and the patient should be notified about the diagnosis and all treatments updates in comprehensible language have 96.6% correct response rate .
doctors are entitled to withholding any procedures related to a patient 's condition if the patient refuses their choice of treatment was the item with the least correct responses ( 15.5% ) .
the knowledge of pbr showed that half ( 52.3% ) of the students knew of the existence of saudi pbr , but only 7.9% of them knew some of the details .
habib and al - siber recommended that more should be done by healthcare providers to increase patients ' awareness of their rights and their role in making decisions on their treatment .
the physicians aged 3140 years had a higher proportion ( 71.9% ) of adequate knowledge in that age category , compared to the proportion of the other age groups .
more than three - fifths of the specialists ( 73.9% ) and consultants ( 68.4% ) had adequate knowledge of pbr compared to that of the other physician categories .
of the physicians who had > 5 years of work experience , 70.9% had adequate knowledge of pbr compared to those with less work experience ( = 9.974 , p = 0.007 ) .
this implies that older , more experienced physicians and more senior doctors had better level of knowledge of pbr . because of their experience and skill in their field , they appreciated the importance of pbr in rendering quality care to patients and their contribution to maintaining the integrity of the institution and protecting themselves from medical lawsuits .
furthermore , multivariate logistic regression analyses also showed that the physicians in the specialist category are 7.04 times more likely to have adequate knowledge on pbr compared to interns ( aor = 7.04 ; 95% ci : 1.0945.52 ) ( p = 0.040 ) .
knowledge on the pbr was inadequate , and reinforcement and strict implementation of pbr are necessary . the institution should train and motivate physicians on pbr , especially younger doctors to ensure good health for all and safeguard the integrity of both the physician and the hospital .
| ### Summary:
: objectives : to assess the level of physicians ' knowledge about the contents of patients ' bill of rights ( pbr ) and its implementation.materials and methods : this cross - sectional study was carried out at a university hospital in the eastern province of saudi arabia .
all physicians working in the hospital received a self - administered questionnaire to measure their level of knowledge of pbr .
scoring was done to determine the knowledge of the details .
the study was approved by the institutional review board of the university hospital and permission sought from the administration .
data analysis performed with spss ; descriptive analyses included frequency and percentages for categorical variables , and mean and standard deviations for continuous variables .
bivariate analyses were carried out to determine association between sociodemographic variables and the level of knowledge ( adequate / inadequate ) .
logistic regression analysis were performed to calculate adjusted odds ratio at 0.05 significance level.results:most ( 52.7% ) of the physicians were females , were aged between 25 and 30 years ( 58.5% ) , and saudi ( 80.2% ) .
the majority of the physicians belonged to the residency program ( 44.9% ) and had work experience of 15 years ( 45.4% ) .
about 44% physicians had adequate knowledge about pbr and 55.56% had inadequate knowledge .
regarding physician 's response to each item of pbr , the majority ( 98.1% ) gave correct answer to item 2 :
patients should know the identity and professional status of the healthcare providers responsible for their treatment ( 98.1% ) .
item 25 :
doctors are entitled to withhold any procedures related to a patient 's condition if the patient refuses their choice of treatment was the item with the least correct response ( 15.5%).conclusion : reinforcement and strict implementation of pbr are necessary .
the institution should provide training and motivate physicians , especially younger doctors regarding pbr to ensure good health for all and safeguard the integrity of both the physician and the hospital . |
<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:
: systemic lupus erythematosus ( sle ) is an autoimmune disease , which is characterized by tissue deposition of circulating immune complexes leading to release of inflammatory mediators , influx of inflammatory cells , and clinically apparent disease .
it is a prototypic systemic disease and has the potential to involve the multiple organ system in contrast to autoimmune diseases such as multiple sclerosis and type 1 diabetes mellitus .
the renal involvement , called lupus nephritis ( ln ) , is one of the most serious complications , and shows the phenotypic and histological heterogeneity . in particular , two polar morphologic forms , diffuse proliferative lupus nephritis ( dpln , world health organization ( who ) class iv ) and membranous lupus nephritis ( mln , who class v ) are representative of histological findings in ln [ 35 ] .
hematuria and proteinuria are present in all dpln patients with active disease , and the nephrotic syndrome , hypertension , and renal insufficiency are all frequently seen .
affected patients typically have significant hypocomplementemia ( especially c3 ) and elevated anti - dna levels , especially during active disease .
patients with dpln usually have an unfavorable prognosis with a high percentage of eventually progressing to a renal failure despite aggressive treatment . on the other hand mln patients
would be predicted to have proteinuria as the most prominent clinical feature and an indolent course similar to that seen with idiopathic membranous glomerulonephritis ( mgn ) .
it is intriguing that two polar morphologic forms exit in the same disease , and what causes the morphologic form determination .
human igg molecules are classified into four igg subclasses according to the immunologically distinct constant region of the heavy chain .
the igg is the most important ig isotype in immunopathogenesis for ln , and accordingly , different igg subclasses have distinct physicochemical and biological properties .
although it should be recalled that glomerular deposited igg subclasses have a role for determination of morphological form , it was demonstrated that distribution of subclass in glomerular igg deposition was not associated with the different histological expressions of dpln and mln ( figure 1 ) .
it is widely recognized that nave cd4 t cells become activated and differentiate into various effector t cell subsets after encountering a specific antigen , t helper type 1 ( th1 ) , th2 , and th17 cells , characterized by distinct patterns of cytokine production .
th1 cells produce mainly interferon- ( ifn- ) , interleukin-2 ( il-2 ) , and tumor necrosis factor- ( tnf- ) , and promote cell - mediated immunity .
th2 cells secreting il-4 , il-5 , and il-10 and are associated with humoral immune responses and induce antibody production .
exaggeration of responses by th1 , th2 , and th17 cells can induce tissue inflammation and another subset of regulatory t cells ( treg cells ) controls these effector t cells for maintenance of the immune response and prevention of autoimmunity and tissue inflammation . various types of treg cells have been described that mediate these regulatory functions .
it has been demonstrated that an imbalance between th1 and th2 cytokine production is much concerned with the induction and development of several autoimmune diseases .
the polarized situation between th1 and th2 cells is established to be important in animal models and human autoimmune diseases .
although a relationship between sle activity and cytokine productions was abundantly reported , cytokine profiles concerned with ln , especially each histologic phenotype have not been sufficiently discussed . in this review
we focus on th subset , which exerts significant effect on the determination of morphological form in ln .
a large number of studies suggested that sle is a th2-driven disease [ 12 , 13 ] .
however , elevation of both th1 and th2 cytokines occurs in both humans and mice suggesting that sle is a complex disease driven by different lymphocyte subsets with heterogeneity of clinical manifestations and organ involvement . in human ln , a relationship between histological classification and th1/th2 balance was suggested .
immunohistological study for nephritis showed the large number of infiltrating macrophages , th1 cells , cd40 positive cells , and osteopontin in dpln , but not in mln .
cd40-cd40l interaction and osteopontin function are known to be involved in early th1-mediated cellular immunity [ 1618 ] .
il-12 is a 70 kda heterodimer ( il12p70 ) produced by macrophages and dendritic cells ( dc ) . in conjunction with il-18
, it promotes ifn- production , and leads to polarization of peripheral cells toward a th1 phenotype . in ln
both serum and urinary il-12p70 elevation was reported and which reflected il-12 production in glomeruli .
although there was no significant difference in the serum values of il-12p70 between dpln and mln , significant difference was shown in the urinary value of il-12p70 .
it was also demonstrated that the value of peripheral ifn-/il-4 ratio in dpln was much greater than that in mln , and these results are coincident with our previous report [ 20 , 21 ] ( figures 2 and 3 ) .
the fact that activity index for dpln was correlated with the value of ifn-/il-4 ratio indicates ifn- plays a principal role in the development of dpln .
it was also shown that large amounts of il-18 have been found within serum and glomeruli of humans ln . however , there was no difference between them in dpln and mln .
mrl / mpj - lpr / lpr ( mrl / lpr ) mice have proven particularly valuable for the investigation of sle pathogenesis .
mrl / lpr mice develop a lupus - like autoimmune disease characterized by severe panisotypic hypergammaglobulinemia , autoantibody production , lymphadenopathy , and immune complex- ( ic-)associated nephritis . because mlr / lpr nephritis involves the glomerulus , interstitium , and vascular components , and shows infiltration of macrophages and t cells , it is considered a suitable histological model for human dpln . moreover , like human dpln , mlr / lpr nephritis is associated with th1 responses .
mrl / lpr mice deficient in the ifn- or its receptor developed significantly reduced dpln [ 24 , 25 ] .
it was also demonstrated that il-18 accelerated dpln , and that dpln was exacerbated by the synergistic action of il-12 and il-18 , a combination known to promote th1 cell development .
it was suggested a predominant th2 cytokine response is associated with mgn pathogenesis [ 21 , 29 , 30 ] .
the deposits stain uniformly with a predominance of igg4 in idiopathic mgn [ 31 , 32 ] , and it was suggested that mgn occurs in individuals who generate igg4 to m - type phospholipase a2 receptor ( pla2r ) .
igg4 is a th2-dependent igg subclass , and il-4 directs nave human b cells to switch to igg4 and ige production .
in addition the fact that chronic graft versus host diseases ( cgvhd ) , in which th2 immune response occurs predominantly , occasionally associates with mgn not diffuse proliferative glomerulonephritis ( dpgn ) , supports the notion that predominant th2 cytokine response is associated with mgn pathogenesis [ 35 , 36 ] .
while mln shows apparently different igg subclass distribution of deposit , and igg eluted from the glomerular deposits in the patient with mln does not recognize pla2r .
however , it was also suggested a predominant th2 cytokine response is associated with mln pathogenesis [ 20 , 29 , 32 ] .
association study between mln and ifn- gene using microsatellite polymorphisms demonstrated that half of the mln patients were homozygous of the allele of lower amount of ifn- production .
this result suggested that the immune response of sle patient bearing lower amount of ifn- production genotype is tend to be predominant to th2 .
it was suggested that genetically determined ifn- production should influence on the histological finding of ln . in murine
ln , mrl / lpr mice disrupted the wsx-1 gene developed disease essentially identical with human mln , accompanied by marked impairment of th1-type immune responses with th2-type immune deviation ( figure 4 ) .
the initial mounting of th1 responses depends on the function of the wsx-1 gene , which encodes a subunit of the il-27r with homology to il-12r .
it is indicated that the phenotypic shift from dpln to mln in mrl / lpr mouse occurred because the loss of wsx-1 impaired the th1 response and concomitantly enhanced the th2 response .
il-17 is mostly produced by cd4 , cd8 , cd4/cd8 , and / t - cells , and th17 cells . in human ln , it was reported that il-17 expressing t - cells migrate to the kidney and contribute to inflammatory processes .
expressions of costimulatory marker cd80 and cd134 on il-17 producing t cells in the peripheral blood in sle patients was increased as compared to healthy controls .
the presence of cd134t - cells in the kidney suggests that these cells after ligation with cd134l expressed by endothelial cells migrate to the kidney and might contribute to inflammatory processes through il-17 secretion .
however , no significant difference in the expressions was seen between in patients with dpln and mln . in murine
ln , relevant amounts of il-17 are produced , and il-17 producing t - cells largely infiltrate the nephritic kidneys of nzb / nzwf1 mice . by contrast , treatment with anti - cd3 monoclonal antibodies delayed the renal damage with concurrent defect of il-17 production in both serum and glomeruli . in mrl / lpr mice
il-6 promotes the proliferation of renal mesangial cells and activates nave t cell differentiation towards th17 cooperated with transforming growth factor- ( tgf- ) .
also it primes the differentiation of b cells into antibody - producing cells . in human ln , infiltrating inflammatory cells in the kidney , mainly macrophages and monocytes , are the main source of il-6 .
in addition to the high il-6 serum levels , significant overexpression of il-6 is found in dpln whereas healthy kidneys show little il-6 expression . in murine
ln , blocking il-6 with anti - il-6 antibodies was able to reduce kidney pathology in mrl / lpr and nzb / nzw mice whereas mice with il-6 overexpression develop mesangial proliferative glomerulonephritis .
il-6-deficient mrl / lpr mice showed delayed onset of proteinuria and hematuria compared to control mice .
the absence of il-6 resulted in significant reduction of infiltrating macrophages in the kidney , a decrease in renal igg and c3 deposition , and a reduction of cd4 and cd8 lymphocytes .
the foxp3 population includes both il-10-producing treg cells and th3 cells that produce tgf-. this cytokine plays crucial roles in the differentiation to cd4cd25foxp3treg .
the expression of foxp3 prevents t - cells from differentiating into th17 proinflammatory effector t - cells . on the other hand tgf- , together with il-6 , promotes the differentiation of th17 cells and suppresses foxp3 , leading to a reduction in treg cells . in human ln ,
the proportion of treg cells in pbmcs and serum and urinary tgf-1 levels were evaluated .
the results demonstrated a significant decrease in the frequency of cd4cd25 and cd4cd25foxp3 t cells in ln patients .
this decrease was accompanied with lower serum tgf-1 levels and higher urinary tgf-1 levels .
it was described that urinary tgf- reflects the grade of interstitial fibrosis in glomerular disease and also the mesangial matrix increase in proliferative glomerulonephritis .
these results make us conceive the idea that th17 cells and treg cells may compete with each other in the process of development of ln , and nevertheless this th17/treg balance tgf- production may be activated . in murine
ln , depletion of cd4/cd25 cells in nzb / nzwf1 accelerates the onset of dpln whereas their transfer into cd4/cd25 ko mice delays the dpln development .
the treatment of antimouse thymocyte globulin ( atg ) in conjunction with tgf-1 for mrl / lpr mice demonstrated inhibition of progression of proteinuria and improvement in long - time survival accompanied with reduced renal histological findings .
it was suggested that atg followed tgf-1 treatment induced the differentiation for cd4cd25foxp3treg .
although this cytokine has been extensively studied , it remains unclear whether elevation of il-10 is a cause of ln or not .
recently il-10 is not considered as a lineage specific cytokine , because it has been shown that not only th2 cells but also th1 cells , th17 , and treg cells can produce il-10 .
we conceive that the overexpression of il-10 in sle might reflect il-10-producing treg cells activation against intrinsic defect of the cytokine homeostasis .
it is interesting that there are two distinct phenotypes , dpln and mln , in histological findings of lupus nephritis despite of being based on the same disease .
although the determinants that account for these differences were still equivocal , recent studies have supported that th1 , il-17 producing t cells and th17 cells play a principal role for dpln . while th2 cells may contribute to development of mln .
similarly treg cells control effector t cells for maintenance of the immune response , and treg / th17 balance may be another determinant for development of ln . | ### Summary:
: lupus nephritis , which has various histological patterns and variable clinical outcomes , is one of the most important complications of systemic lupus nephritis ( sle ) .
this pathogenetic mechanism in each histologically different type of lupus nephritis ( ln ) remains unclear .
although sle is suggested to be a th2-driven disease , elevation of both th1 and th2 cytokines occurs in both humans and mice , suggesting that sle is a complex disease driven by different lymphocyte subsets with high heterogeneity of clinical manifestations and organ involvement .
recent findings in ln elucidate an essential role for the th1 , il-17 producing t cells and th17 cells in the development of diffuse proliferative lupus nephritis ( dpln ) , and th2 cytokine in that of membranous lupus nephritis ( mln ) .
these data support the hypothesis that individual th1/th2 balance is one of the critical determinants for histopathology of ln . |
<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:
: thirty - eight consecutive patients ( for a total of 41 eyes ) with pathologic myopia and subfoveal cnv who were treated with verteporfin ( visudyne , novartisag , basel , switzerland ) pdt at yonsei university medical center between may 2002 and august 2004 were identified .
two patients were excluded because they were lost to follow - up , and the remaining 36 completed at least 12 months of follow - up .
informed consent was obtained from all patients , and approval from the institution 's ethics committee was not required for this retrospective study .
pathologic myopia was defined as when an eye required a distance correction of at least -6.0 diopters ( d = spherical equivalent ) .
patients with angioid streaks , evidence of histoplasmosis , choroiditis , idiopathic cnv , or other causes of cnv were excluded from the study .
pdt was administered by one surgeon ( ow kwon ) according to the vip and tap study protocol6,7,19,20 with follow - ups at one week , one month , and three months after the therapy , and then every three months thereafter .
if there were any signs of fluorescein leakage three months after pdt , then the pdt was repeated .
fluorescein angiography and icg angiography were repeated for the initial examination and at every subsequent follow - up visit .
all patients received comprehensive ocular examinations ( including dilated fundus photography , fluorescein angiography and icg angiography ) at the baseline investigation and again every three months thereafter .
the patient characteristics retrieved from the medical charts included age , gender , refractive errors , etdrs visual acuity , and the number of treatments .
the greatest linear dimension ( gld ) ( including the cnv , area of leakage and the area of blocked fluorescence in the lesion , according to the tap study ) was measured manually on the fluorescein angiograms.19 indocyanine green ( icg ) angiography was performed with a scanning laser ophthalmoscope ( hra , heidelberg engineering , dossenheim , germany ) .
the icg angiograms were reviewed by two examiners ( sh byeon and hj koh ) to determine the lesion size on icg angiography ratio of the total area of the lesion divided by the area of the optic disc ( da = disc area) and any associated findings , including hypofluorescence surrounding the cnv ( dark rim ) , lacquer cracks , prominent large choroidal veins in the macula , and peripapillary choroidal atrophy size.21 - 24 the presence of an icg angiographic dark rim ( hypofluorescence around the cnv ) was defined as a round - shaped background hypofluorescence within which a hyperfluorescent island appeared during the early phase ( fig . 1 , 2).15 - 18 lacquer cracks were identified using late - phase icg angiography ( figures 1 and 3).16,22 regarding the presence of visible large choroidal veins under the macula , the focal dilation of the choroidal veins in the posterior fundus during the early phase of icg angiography was defined ; some showed hyperfluorescence until the late - phase of the angiogram ( fig . 2).16,23 the area of peripapillary atrophy ( islands of non - perfusion or reduced perfusion in the deep choroid in early or late hypoflurorescence ) was defined as the ratio of the total area of peripapillary atrophy divided by the disc area on icg angiography.22,24 to evaluate the relative impact of the baseline predictors ( the clinical and icg angiographic features ) on the visual outcome , a linear regression analysis was performed .
the main outcome measure was the change in the logmar value during the follow - up period ( logmar ) , which was obtained by subtracting the baseline logmar value from the final logmar value 12 months after pdt .
a linear regression analysis was performed using the change in visual acuity ( logmar ) as the dependent variable and the above factors as independent variables .
all reported p - values were the results of two - sided tests , and p - values 0.05 were considered statistically significant .
spss 12.0 software for windows ( chicago , illinois , usa ) was used for statistical calculations .
thirty - nine eyes from 36 patients with subfoveal cnv secondary to pathologic myopia had completed 12 months of follow - up .
the mean age of patients at presentation was 44.1 [ standard deviation ( sd)=15.0 ] years , with a range from 25 to 74 years .
refractive errors ranged from -6.00d to -23.00d , and the mean was -10.78 ( sd=3.80 ) d. the average number of treatments during the 12 months of follow - up was 2.4 ( sd=1.2 ) .
the mean great linear dimension ( gld ) of lesions on fluorescein angiography was 1775 ( sd=976 ) m ( range= 400 - 4280 ) at presentation .
submacular hemorrhages visible on fundus photography and fluorescein angiography were found in 8 of 39 eyes .
the mean area of lesions visible on icg angiography was 0.71 ( sd=0.61 ) da ( range=0.08 - 2.24 ) .
the mean area of peripapillary choroidal atrophy on icg angiography was 2.0 ( sd=2.4 ) da . the hypofluorescence surrounding the cnv ( dark rim ) was found in 15 of 39 eyes , and prominent large choroidal veins were noted under the macula in 13 of 39 eyes . the presenting best - corrected visual acuity measured with
an etdrs chart was greater than 20/40 in four ( 10.3% ) eyes , from 20/40 to 20/200 in 26 ( 66.7% ) eyes , and less than 20/200 in nine ( 23.0% ) eyes .
the baseline mean logmar was 0.82 ( sd=0.43 ) . at the 12-month follow - up ,
the best - corrected visual acuity was greater than 20/40 in six ( 15.4% ) eyes , from 20/40 to 20/200 in 25 ( 64.1% ) eyes , and less than 20/200 in eight ( 20.5% ) eyes .
the change in visual acuity from baseline at the 12-month follow - up was six lines or more of visual acuity improvement in seven eyes ( 18% ) , one to six lines of improvement in 14 eyes ( 36% ) , no change in nine eyes ( 23% ) , and a one - line or more decrease in visual acuity in nine eyes ( 23% ) .
when clinical features including age , gender , refractive error , baseline visual acuity , baseline gld , and submacular hemorrhage , and icg features such as the size of cnv , lacquer cracks , area of peripapillary atrophy , dark rim , and a prominent large choroidal vein were examined as prognostic factors by univariate analysis , both age and the presence of a dark rim had a statistically significant effect on a change in logmar(logmar ) at 12 months ( table 1 ) . on a multivariate analysis , age and
the presence of a dark rim still remained statistically significant at the 12-month follow - up ( table 1 , fig .
thirty - nine eyes from 36 patients with subfoveal cnv secondary to pathologic myopia had completed 12 months of follow - up .
the mean age of patients at presentation was 44.1 [ standard deviation ( sd)=15.0 ] years , with a range from 25 to 74 years .
refractive errors ranged from -6.00d to -23.00d , and the mean was -10.78 ( sd=3.80 ) d. the average number of treatments during the 12 months of follow - up was 2.4 ( sd=1.2 ) .
the mean great linear dimension ( gld ) of lesions on fluorescein angiography was 1775 ( sd=976 ) m ( range= 400 - 4280 ) at presentation .
submacular hemorrhages visible on fundus photography and fluorescein angiography were found in 8 of 39 eyes .
the mean area of lesions visible on icg angiography was 0.71 ( sd=0.61 ) da ( range=0.08 - 2.24 ) .
the mean area of peripapillary choroidal atrophy on icg angiography was 2.0 ( sd=2.4 ) da . the hypofluorescence surrounding the cnv ( dark rim ) was found in 15 of 39 eyes , and prominent large choroidal veins were noted under the macula in 13 of 39 eyes .
the presenting best - corrected visual acuity measured with an etdrs chart was greater than 20/40 in four ( 10.3% ) eyes , from 20/40 to 20/200 in 26 ( 66.7% ) eyes , and less than 20/200 in nine ( 23.0% ) eyes .
the baseline mean logmar was 0.82 ( sd=0.43 ) . at the 12-month follow - up ,
the best - corrected visual acuity was greater than 20/40 in six ( 15.4% ) eyes , from 20/40 to 20/200 in 25 ( 64.1% ) eyes , and less than 20/200 in eight ( 20.5% ) eyes .
the change in visual acuity from baseline at the 12-month follow - up was six lines or more of visual acuity improvement in seven eyes ( 18% ) , one to six lines of improvement in 14 eyes ( 36% ) , no change in nine eyes ( 23% ) , and a one - line or more decrease in visual acuity in nine eyes ( 23% ) .
when clinical features including age , gender , refractive error , baseline visual acuity , baseline gld , and submacular hemorrhage , and icg features such as the size of cnv , lacquer cracks , area of peripapillary atrophy , dark rim , and a prominent large choroidal vein were examined as prognostic factors by univariate analysis , both age and the presence of a dark rim had a statistically significant effect on a change in logmar(logmar ) at 12 months ( table 1 ) . on a multivariate analysis , age and
the presence of a dark rim still remained statistically significant at the 12-month follow - up ( table 1 , fig .
more than 50% of the myopic cnv patients showed visual improvement 12 months after pdt .
we found that patients older than 50 years rarely had visual improvement following pdt after 12 months of follow - up .
both the age at onset and the icg angiographic feature ( dark rim ) were related to a change of visual acuity from the baseline . a younger age and
other factors such as gender , refractive error , baseline visual acuity , baseline gld , submacular hemorrhage , and icg features ( including the size of the cnv , lacquer cracks , area of peripapillary atrophy , and a prominent large choroidal vein ) were not predictive of outcome when the age and presence of a dark rim were accounted for .
our series contained a relatively large number of patients who had a visual improvement after pdt.6,7,8 - 10,25 this may be due to the younger age distribution in our series compared to other studies . among our participants , 24 eyes ( 62% ) from 22 patients
their baseline characteristics were similar to those who had finished a 12-month follow - up ( data not shown ) .
the 24-month mean logmar value improved to 0.80 ( sd=0.57 ) . in our 24-month follow - up group
, a multivariate regression model also showed that a younger age ( p=0.012 ) and a dark rim ( p=0.031 ) were significantly correlated with an improvement of visual acuity at the 24-month follow - up .
previous reports have suggested that patients who were younger at the onset of cnv might be able to retain good vision even without any treatment during follow - up . because our study did not have a comparative group , it was not clear whether the better visual outcomes of young patients in our series were due to an effect of pdt or to the natural characteristics of myopic cnv in young patients .
reports on the natural history of cnv in high myopia patients vary , and most to date provide conflicting information.6,7,26 - 31 this may be because those studies enrolled a variety of eligible patients , represented variable lesion topographies , contained different patient age distributions , and had variable follow - up periods .
our study had similar eligibility criteria and age distributions to yoshida 's series,28 which found that younger , myopic cnv patients retained good visual acuity without any treatment .
japan and korea have ethnic and geographic similarities as well as a prevalence of high myopia .
yoshida examined 63 consecutive patients ( 73 eyes ) with myopic cnv , and then divided the patients into two groups according to their ages ( 40 and > 40 years old ) .
, we also divided our patients into two groups at the age of 40 ( table 2 ) .
in our study , the younger group ( 40 ) had significant improvement in visual acuity . in his natural history series ,
even though the younger patients retained relatively good visual acuity , they did not have significant visual improvement .
we could hypothesize that pdt might increase the chance of visual improvement in myopic cnv patients , especially in the younger patient group . however , our study had a shorter follow - up period and our patients had a smaller mean refractive error . in our 12-month multivariable regression model ,
the age of patients at onset significantly influenced their visual outcome , and a dark rim was another covariate significantly affecting the end results .
we also found that this dark rim was more prominent as the cnv regressed with pdt during follow - up ( figure 1 ) .
we are the first group to study the dark rim as a predictive factor for visual outcome in cnv .
histologically , a dark rim corresponds to the multilayered , proliferated retinal pigment epithelium at the outer margin of the neovascular membrane.18,21 if large parts of the cnv remained unperfused for several weeks after pdt , the adjacent rpe cells may benefit from the interval required for the restoration of the cnv , and they could also migrate and proliferate around the vascular net.32 we postulated that patients with a dark rim had more potent regenerative potential of rpe and received a greater benefit from pdt .
it was thought that the dark rim found on the baseline icg angiography could be another indicator of the potent regenerative potential of rpe . in age - related macular degeneration ,
the visual prognosis after pdt is related to the fluorescein angiographic subtype of cnv.19 - 20 the size of the cnv is also related to the prognosis . however , in myopic cnv , the relationship between the size of the cnv and visual outcome has not been fully determined.6 - 10,25 in our series , there was no significant relationship between size and visual outcome .
new vessels originating from the choroids and the hemodynamic characteristics of new vessels must depend on those of the choroids . in eyes with severely decompressed choriocapillaries , the size and activity of neovascularization might be decreased . the visual prognosis
could not only be influenced by the characters of the cnv but also by the state of the choroids and the choriocapillaries .
lacquer cracks are imaged using enhanced delineation with late phase icg angiography.16,22 there were a few reports regarding the pathophysiological relationship between lacquer cracks , cnv and visual outcomes.22,33 however , in our results the presence of lacquer cracks had no significant effect on visual outcome after pdt .
there have been reports that an anatomic connection of the choroids with the arteries or veins is a factor influencing the natural course of cnv.16,23,34,35 we postulated that the visible prominent choroidal veins in the macula may reflect a thinned choroidal vasculature , which may in turn affect the visual prognosis of myopia . in our study , there were no significant relationships between the presence of a choroidal vein and the visual outcomes at the 12- and 24-month follow - ups ( data not shown ) . in the univariate analysis of choroidal vessels on 24-month follow - up , the presence of a prominent choroidal vein in the macula correlated with a decrease in visual acuity , even though it was not significant ( p=0.090 ) .
this relationship was the third - smallest p - value have an influence on the change in the logmar value after 24 months , and it might be more prominent if it were to be examined over a longer period of time .
our study , however , has its own limitations , including a small sample size , a short follow - up period and no comparative control group .
prevention of later chorioretinal atrophy development and further visual decrease over the long - term could not be assessed.36 patients ' ages at onset and icg angiographic features ( dark rim ) were the significant prognostic indicators of the visual outcome after pdt in our study . in conclusion , younger patients and patients with a dark rim on icg angiography had a higher chance of visual improvement after pdt in myopic cnv . | ### Summary:
: purposeto determine the influence of clinical features and indocyanine green ( icg ) angiographic features on the visual outcome of patients with myopic sub - foveal choroidal neovascularization ( cnv ) who received photodynamic therapy ( pdt).methodsthirty - six consecutive patients ( 39 eyes ) with myopic cnv who were followed up for more than one year after pdt were enrolled in this study .
clinical features included age , gender , refractive error , great linear dimension , and subretinal hemorrhage .
icg features included the lesion size , lacquer cracks , hypofluorescence surrounding the cnv ( dark rim ) , peripapillary atrophy size , and visible prominent choroidal veins under the macula .
linear regression analysis was performed using the change in visual acuity ( logmar ) as the dependent variable and the above factors as independent variables.resultsat one - year follow - up after pdt , a younger age ( p=0.002 ) and the presence of a dark rim ( p=0.002 ) were significantly correlated with an improvement of visual acuity ( decrement in logmar ) after pdt .
other factors had no significant influence on changes in visual acuity.conclusionsyounger patients and patients with a dark rim on icg angiography had a higher chance of visual improvement after pdt in myopic cnv . |
<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:
: emphysematous pyelonephritis is a rare but life threatening necrotizing infection of the kidney caused by gas - forming bacteria .
patients usually present with features of acute severe pyelonephritis , positive blood and urine cultures ( in majority ) , urosepsis , and shock .
pathogenesis of ep is unclear but diabetes and obstructing urinary calculi are the commonest predisposing factors .
other risk factors are immune - suppression , alcoholism , cirrhosis , and kidney failure .
a 49-year - old male presented to our hospital with complaints of generalized weakness and polydipsia for two weeks .
there was no history of fever , abdominal pain , or lower urinary tract symptoms .
blood urea nitrogen was 20 mg / dl and serum creatinine was 1.6 mg / dl .
ultrasound revealed multiple hyper echoic areas with dirty distal acoustic shadowing ( gas ) in all calyces and within the renal parenchyma of the mildly enlarged right kidney ( rk ; size of rk 12.6 x 6.9 cm ) , no intrarenal or perinephric collection was seen and the pelvicalyceal system was compact ( fig .
the left kidney ( lk ; size 9.2 cm ) showed a 6 mm calculus in the midpole calyx .
longitudinal scan of the right kidney showing echogenic foci of air ( arrow ) inside the renal parenchyma .
non - contrast computed tomography ( ct ) showed gas within the parenchyma of the rk and small radiopaque shadow ( calculus ) in the midpole of the lk ( fig .
2 ) . non - contrast ct scan showed gas within the parenchyma of right kidney and small radiopaque shadow ( calculus ) in the midpole of left kidney .
diagnosis of ep was made on the basis of imaging [ 2 , 3 , 4 ] .
after three weeks of hospitalization he had improved sense of well being , with no symptoms escalation .
ultrasound showed both kidneys echogenic with no evidence of gas or hydronephrosis , a small 5 mm calculus in lower pole of lk was noted .
tc-99 m diethylene - triamine - penta - acetic acid ( dtpa ) renogram showed bilateral compromised function ( left > right ) with glomerular filtration rate ( gfr ) of 22.5 ml / min , and 12 ml / min of right and left kidneys respectively , and good drainage on both sides . glucoheptonate renogram ( gha scan ) showed irregular contoured right kidney with linear photopenic defect in the anterolateral aspect with heterogeneously decreased uptake and linear photopenic defect in the anterior aspect of left kidney noted .
ep presents particularly in diabetic ( dm ) patients and is associated with obstructive uropathy .
it is associated with high mortality rate . in a meta - analysis published by falagas
there was a 25% mortality rate with an 11 - 42% range in a total of 175 patients .
our case presented with nonspecific , generalized symptoms and detected to have type 2 diabetes mellitus . during evaluation for diabetes
he was found to have gas in the pelvicalyceal system and renal parenchyma of the right kidney .
this was a class 2 emphysematous pyelonephritis , as per classification system given by huang et al . .
we did not consider any surgical intervention at first place since patient was stable , afebrile and asymptomatic .
his bilateral scarred and poorly functioning kidneys can be attributed to diabetic nephropathy , superimposed by recurrent low - grade infection . however , the absence of systemic symptoms in presence of class 2 emphysematous pyelonephritis and uncontrolled blood sugar was unclear .
it can probably be explained by a decreased local tissue immune response due to the high tissue glucose level and impaired tissue perfusion and / or low virulence of the gas forming organism .
it is further supported by the fact observed by huang et al . that poor control of blood glucose levels is not a risk factor of poor prognosis for epn [ 1 , 9 ] .
the patient presented here was incidentally detected to have emphysematous pyelonephritis during evaluation for diabetes and was successfully treated with medical management . | ### Summary:
: emphysematous pyelonephritis ( ep ) is a rare , severe gas forming infection of renal parenchyma and its surrounding areas and potentially life threatening condition that requires prompt evaluation and treatment .
although it commonly present with a fulminant clinical picture of sepsis , relatively mild symptoms can also be encountered . to our knowledge , incidentally detected emphysematous pyelonephritis has not been reported so far .
we report a case of ep that was incidentally detected during evaluation for diabetes . |
<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 age range of 6 to 15 years corresponds to a very sensitive period of life when children start going to school and discover themselves and have experiences .
any handicap or impairment occurring during that time may have a heavy psychosocial impact on the child , especially in their quality of life .
three percent of blind worldwide are children.1 many causes of childhood blindness can be prevented or treated.2 the prevalence of childhood blindness is usually estimated at 0.8 per 1,000 children.3 nearly 500,000 children become blind each year ; consequently the fight against childhood blindness has become a priority for the vision 2020 global initiative.4 in cameroon , little has been published on unilateral blindness in childhood in its epidemiological aspect .
for that reason , we decided to look for the causes of unilateral childhood blindness in school pupils aged 6 to 15 years .
we conducted a prospective and analytic study over a period of twelve months from january 2nd to december 31st , 2008 at the gynaeco - obstetric and paediatric hospital of yaound , cameroon .
recruited candidates were school - attending children aged 6 to 15 years and presenting for the first time in our ophthalmology outpatients consultation clinic .
all children underwent a complete comprehensive ocular exam to build a patient history with emphasis on the present complaint , history of the complaint , ocular history , and past medical history .
visual acuity was assessed for near and far vision in one eye at a time using the snellen eye chart for the older patients and the tumbling
e or landolt c chart for the younger patients , slit lamp examination of the anterior and posterior segment , and evaluation of intraocular pressure with an air pulse tonometer . the world health organization ( who ) defines childhood blindness as visual acuity less than 3/60 in the better eye with the best - corrected visual acuity in children aged 0 to 15 years.3 we considered every child presenting with visual acuity less than 3/60 ( 1/20 ) in one eye and the other eye having a visual acuity superior or equal to 6/18 ( 3/10 ) to be unilaterally blind .
the data analyzed using the epi info 6.04 program ( centers for disease control and prevention , atlanta ,
ga , usa ) were : age , sex , past history , visual acuity with best correction , unilateral blindness and its etiology .
the parents or guardians of the recruited patients had to complete a questionnaire , which included , among other information , the future occupation or profession they wished for their children .
as a reference , we used the who anatomical classification of childhood blindness and its etiology.4 the chi - squared test was used for comparison and was considered significant if p < 0.05 .
a total of 1,266 children aged 6 to 15 years were examined : 663 girls ( 52.37% ) and 603 boys ( 47.63% ) ( table 1 ) . among these children ,
60 were diagnosed unilaterally blind ( a hospital prevalence of 4.7% : 42 boys [ 6.96% ] , 18 girls [ 2.71% ] , and a sex ratio m / f of 2.33 ; p = 0.0037 ) .
the age group of 11 to 15 years ( 33 children , 4.41% ) was the most represented followed by the 6 to 10 years ( 27 children , 5.2% ) ( table 2 ) .
the right eye was more affected in 39 cases ( 65% ) while the left eye was registered in 21 cases ( 35% ) ( p = 0.01 ) .
examination of the events surrounding the origin of the child s ocular problem and latter blindness revealed episodes of trauma in 39 cases ( 65% ) out of the 60 cases of unilateral blindness ( p = 0.000 ) .
one hundred eight of the 1,266 children ( 8.53% ) had history of ocular trauma ( 88 had contusions [ 81.48% ] and 20 had penetrating injuries [ 18.52% ] ) .
boys were relatively more involved than girls especially in blinding traumas ( p = 0.05 ) .
nontraumatic ocular pain before blindness were mentioned in 12 cases ( 20% ) followed by proptosis in six cases ( 10% ) and three cases of monocular blindness occurred in a
white eye with progressive loss of vision ( table 3 ) . according to the who anatomical classification of etiologies of blindness ,
etiologies of unilateral blindness in children ( table 4 ) were more often represented by pathologies of the uveal tissues in 15 cases ( 25% ) : nine cases of endophtalmitis following penetrating trauma , three cases of panuveitis , and three of traumatic hyphemas .
these were followed by lesions of the lens with 12 cataracts ( 20% ) among which were 11 cases of trauma and one congenital unilateral cataract .
in the third position , pathologies involving the whole globe were found in nine cases ( 15% ) composed of eight phthisis bulbi and one traumatic avulsion of the globe .
six cases ( 10% ) of orbital tumors with a prevalence of 0.47% were the causes of unilateral blindness . among those six cases ,
burkitt s lymphoma was diagnosed twice and the other four cases could not be determined by differentiation . with a prevalence of 0.71% ,
the nine cases of glaucoma were of infantile asymmetric glaucoma in eight cases and one case of unilateral traumatic glaucoma in a terminal stage .
a total of 1,266 children aged 6 to 15 years were examined : 663 girls ( 52.37% ) and 603 boys ( 47.63% ) ( table 1 ) . among these children ,
60 were diagnosed unilaterally blind ( a hospital prevalence of 4.7% : 42 boys [ 6.96% ] , 18 girls [ 2.71% ] , and a sex ratio m / f of 2.33 ; p = 0.0037 ) .
the age group of 11 to 15 years ( 33 children , 4.41% ) was the most represented followed by the 6 to 10 years ( 27 children , 5.2% ) ( table 2 ) .
the right eye was more affected in 39 cases ( 65% ) while the left eye was registered in 21 cases ( 35% ) ( p = 0.01 ) .
examination of the events surrounding the origin of the child s ocular problem and latter blindness revealed episodes of trauma in 39 cases ( 65% ) out of the 60 cases of unilateral blindness ( p = 0.000 ) .
one hundred eight of the 1,266 children ( 8.53% ) had history of ocular trauma ( 88 had contusions [ 81.48% ] and 20 had penetrating injuries [ 18.52% ] ) .
boys were relatively more involved than girls especially in blinding traumas ( p = 0.05 ) .
nontraumatic ocular pain before blindness were mentioned in 12 cases ( 20% ) followed by proptosis in six cases ( 10% ) and three cases of monocular blindness occurred in a
white eye with progressive loss of vision ( table 3 ) . according to the who anatomical classification of etiologies of blindness ,
etiologies of unilateral blindness in children ( table 4 ) were more often represented by pathologies of the uveal tissues in 15 cases ( 25% ) : nine cases of endophtalmitis following penetrating trauma , three cases of panuveitis , and three of traumatic hyphemas .
these were followed by lesions of the lens with 12 cataracts ( 20% ) among which were 11 cases of trauma and one congenital unilateral cataract . in the third position ,
pathologies involving the whole globe were found in nine cases ( 15% ) composed of eight phthisis bulbi and one traumatic avulsion of the globe .
six cases ( 10% ) of orbital tumors with a prevalence of 0.47% were the causes of unilateral blindness . among those six cases ,
burkitt s lymphoma was diagnosed twice and the other four cases could not be determined by differentiation . with a prevalence of 0.71% ,
the nine cases of glaucoma were of infantile asymmetric glaucoma in eight cases and one case of unilateral traumatic glaucoma in a terminal stage .
we found a prevalence of 4.7% for unilateral blindness in children aged 6 to 15 years in our hospital - based cameroonian population .
this prevalence is about two and a half times higher than the prevalence reported in the general cameroonian population in 1993.6 in the same study , the authors published a level of unilateral blindness of 0.1% in the age group of 5 to 19 years , which is fifty times less than our findings .
our hospital - based prevalence is five times higher than the findings in a community - based study in ethiopia where the reported prevalence of unilateral childhood blindness was 1%.7 these marked differences could be explained by the studied population and the site of recruitment .
we report results of a hospital - based study while the ethiopia study reported those of a population - based study which represented a mixture of healthy and unhealthy people . compared to a hospital - based study undertaken among working young adults in bamako , mali,8 where the prevalence of unilateral blindness was 11.5% , this was two and half times higher than ours .
this suggests that the rate of unilateral blindness is more frequent in working young adults than in school pupils . in the bamako series
, the group of working young adults was represented by farmers and illiterates who were exposed to risk factors such as the great distance from their homes to the health centers , exposure to the risk of further trauma , and other factors .
this matches the results of migliani and colleagues6 whose m / f ratio was 1.71 in the age group of 5 to 19 years .
the predominance of boys can be explained by their recorded history : 65% of unilateral blindness was caused by a great diversity of ocular trauma .
this is why they are more affected9 and because of their boldness , boys are often punished by parents , guardians , or school teachers ,
during which ocular trauma also occur.9 child corporal punishment is still standard practice for correction in cameroon whether in schools or at home ; these are traditional methods of education in which people believe , despite the fact that they have been identified as major causes of traumas,10,11 especially ocular trauma in childhood.9,12,13 all age groups are affected by unilateral blindness ( p = 0.7 ) .
we could not explain the predominance of unilateral blindness in the right eye , but the possible cause may be trauma coming from the left hand of people or parents when fighting or receiving corporal punishment . compared to our findings where trauma was the leading causes of unilateral blindness , the most common causes of unilateral childhood blindness in a saudi arabia study,5 included trauma ( 30% ) , retinal diseases ( 17% ) , and refractive errors ( 15% ) . in ethiopia ,
corneal scarring contributed to 62.5% of unilateral blindness7 compared with our study where corneal opacities contributed to 10% of unilateral blindness .
corneal opacities were ranked number four in our series , and were mostly due to traumas and diseases such as corneal ulcers neglected by parents .
uveal involvement and pathologies of the lens ( cataract ) were complications of ocular traumas and the leading pathologies in unilateral blindness according to our results . with a prevalence of 0.4% ,
orbital tumors have a bad vital as well as functional prognosis according to the degree of malignity .
burkitt s lymphoma is the most frequent orbital tumor in childhood according to the african literature1416 and our results support this frequency . in our third rank after
cataract is unilateral blindness due to infantile glaucoma , which is the result of a quiet and slow - growing process specific to this pathology . when the decreased vision is observed , amblyopia has already taken place with severe damage to the optic nerve head.17 parents with children diagnosed with unilateral blindness hoped that their children would find future occupations as medical practitioners ( 40% ) , aircraft pilots ( 25% ) , soldiers ( 20% ) , lawyers ( 10% ) , and secretaries ( 5% ) .
most of these occupations require good binocular visual acuity and many of these dreams will hardly be realized .
the ocular traumas causing up to 65% of unilateral blindness in our series should be discussed , condemned , and prevented in families as well as in schools . in their study of the epidemiological aspect of ocular traumas in abidjan , cote divoire , mensah and colleagues18 reported a rate of unilateral blindness of 64.5% before management , which improved to 55% after adequate treatment .
we found a prevalence of 4.7% for unilateral blindness in children aged 6 to 15 years in our hospital - based cameroonian population .
this prevalence is about two and a half times higher than the prevalence reported in the general cameroonian population in 1993.6 in the same study , the authors published a level of unilateral blindness of 0.1% in the age group of 5 to 19 years , which is fifty times less than our findings .
our hospital - based prevalence is five times higher than the findings in a community - based study in ethiopia where the reported prevalence of unilateral childhood blindness was 1%.7 these marked differences could be explained by the studied population and the site of recruitment .
we report results of a hospital - based study while the ethiopia study reported those of a population - based study which represented a mixture of healthy and unhealthy people . compared to a hospital - based study undertaken among working young adults in bamako , mali,8 where the prevalence of unilateral blindness was 11.5% , this was two and half times higher than ours .
this suggests that the rate of unilateral blindness is more frequent in working young adults than in school pupils . in the bamako series
, the group of working young adults was represented by farmers and illiterates who were exposed to risk factors such as the great distance from their homes to the health centers , exposure to the risk of further trauma , and other factors .
this matches the results of migliani and colleagues6 whose m / f ratio was 1.71 in the age group of 5 to 19 years .
the predominance of boys can be explained by their recorded history : 65% of unilateral blindness was caused by a great diversity of ocular trauma .
this is why they are more affected9 and because of their boldness , boys are often punished by parents , guardians , or school teachers , during which ocular trauma also occur.9 child corporal punishment is still standard practice for correction in cameroon whether in schools or at home ; these are traditional methods of education in which people believe , despite the fact that they have been identified as major causes of traumas,10,11 especially ocular trauma in childhood.9,12,13 all age groups are affected by unilateral blindness ( p = 0.7 ) .
we could not explain the predominance of unilateral blindness in the right eye , but the possible cause may be trauma coming from the left hand of people or parents when fighting or receiving corporal punishment .
compared to our findings where trauma was the leading causes of unilateral blindness , the most common causes of unilateral childhood blindness in a saudi arabia study,5 included trauma ( 30% ) , retinal diseases ( 17% ) , and refractive errors ( 15% ) . in ethiopia ,
corneal scarring contributed to 62.5% of unilateral blindness7 compared with our study where corneal opacities contributed to 10% of unilateral blindness .
corneal opacities were ranked number four in our series , and were mostly due to traumas and diseases such as corneal ulcers neglected by parents .
uveal involvement and pathologies of the lens ( cataract ) were complications of ocular traumas and the leading pathologies in unilateral blindness according to our results . with a prevalence of 0.4% ,
orbital tumors have a bad vital as well as functional prognosis according to the degree of malignity .
burkitt s lymphoma is the most frequent orbital tumor in childhood according to the african literature1416 and our results support this frequency . in our third rank after
cataract is unilateral blindness due to infantile glaucoma , which is the result of a quiet and slow - growing process specific to this pathology . when the decreased vision is observed , amblyopia has already taken place with severe damage to the optic nerve head.17
parents with children diagnosed with unilateral blindness hoped that their children would find future occupations as medical practitioners ( 40% ) , aircraft pilots ( 25% ) , soldiers ( 20% ) , lawyers ( 10% ) , and secretaries ( 5% ) .
most of these occupations require good binocular visual acuity and many of these dreams will hardly be realized .
the ocular traumas causing up to 65% of unilateral blindness in our series should be discussed , condemned , and prevented in families as well as in schools . in their study of the epidemiological aspect of ocular traumas in abidjan , cote divoire , mensah and colleagues18 reported a rate of unilateral blindness of 64.5% before management , which improved to 55% after adequate treatment .
it helped us to acknowledge the high rate of unilateral blindness among children in cameroon , 65% of which is due to ocular trauma .
these cases of blindness are avoidable and their incidence could be reduced if strategies of education and increasing awareness about the implications and the visual outcome of ocular trauma among parents , teachers , and children are put in place with strong emphasis
. on the other hand , early and adequate management of nontraumatic ocular pathologies in childhood such as orbital tumors and infantile glaucoma will considerably reduce their poor vital and functional prognosis for vision in children . | ### Summary:
: introduction : we performed an analytic and prospective study over a period of 12 months from january 2nd to december 31st , 2008 , at the gynaeco - obstetric and paediatric hospital of yaound , cameroon .
our aim was to determine the prevalence and causes of unilateral blindness in school children aged 6 to 15 years.results:among the 1,266 children aged 6 to 15 years who were recruited , 60 presented with unilateral blindness ( 4.7% ) : 42 boys ( 6.96% ) and 18 girls ( 2.71% ) .
the mean age was 10.15 3.4 years . in patients with unilateral blindness ,
65% was due to ocular trauma.discussion:the hospital - based prevalence of unilateral blindness in children is relatively high and ocular trauma is the leading etiology.conclusion:unilateral blindness in school children is avoidable and its incidence could be markedly reduced by emphasizing an information strategy and education based on prevention of ocular trauma .
early management of nontraumatic diseases such as infantile glaucoma and some tumors could improve outcome and avoid blindness . |
<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:
: multiple myeloma ( mm ) is a mature b - cell malignancy which accounts for 13% of all hematologic malignancies in whites and 33% in blacks .
it is characterized by a clonal expansion of plasma cells , typically within the bone marrow but sometimes also in extramedullary sites .
cns involvement in mm ( cns - mm ) remains rare , accounting for 1% of all mm cases , and exhibits a dismal prognosis with an overall survival ( os ) of less than 6 months .
these include cns - mm cases both at the time of diagnosis as well as relapse .
cns involvement is defined by the presence of monoclonal malignant plasma cells in the csf during the course of mm disease , with or without radiologic features on magnetic resonance imaging ( mri ) suggestive of mm .
relapse of mm with isolated cns involvement , after attainment of complete remission ( cr ) post - asct ( autologous stem cell transplantation ) , is even less common and is reported only as case reports or small case series .
novel agents ( na ) in the last decade have improved the outlook for patients with mm .
one of the more commonly used na , the proteasome inhibitor ( pi ) , bortezomib ( velcade ) is frequently associated with peripheral neuropathy .
this case underscores the importance of maintaining a high level of suspicion for cns relapse while patients are on bortezomib - based regimens , even in the absence of biomarkers and clinical parameters commonly associated with cns involvement , as a missed diagnosis may result in inferior outcomes .
a 57 year - old chinese female with no other past medical history of significance , presented with recurrent epistaxis and was found to have thrombocytopaenia .
subsequent investigations showed infiltration of the bone marrow with clonal plasma cells with plasmablastic morphology .
her skeletal survey was normal ; however , there were fluorodeoxyglucose ( fdg)-avid bone lesions on pet - ct .
she was diagnosed with iss stage ii , igg kappa multiple myeloma ( mm ) with normal cytogenetics .
she underwent 4 cycles of bortezomib , cyclophosphamide and dexamethasone ( vcd ) and achieved very good partial remission ( vgpr ) .
thereafter she underwent asct with a reduced dose of melphalan ( 140 mg / m2 ) due to renal impairment .
she was subsequently treated with monthly bortezomib maintenance but developed peripheral neuropathy during the fifth month of maintenance after sct .
her main symptoms were paraesthesia and numbness in the palms and soles which worsened despite symptomatic treatment and discontinuation of bortezomib .
her neurologic examination revealed decreased proprioception in a glove and stocking distribution , areflexia , bilateral foot drop and power of 3/5 in the right arm and leg .
an mri brain showed lytic bone lesions with dural - based masses within both occipital lobes .
lesions suspicious of myelomatous involvement were also detected in the pituitary , hypoglossal canal , cavernous sinus and sella turcica .
cerebrospinal fluid ( csf ) cytology revealed 88% plasma cells which were confirmed by flow cytometry .
her csf plasma cell morphology and flow cytometric immunophenotyping are shown in figs . 1 and 2 respectively .
she underwent concurrent cranial irradiation with intra - thecal ( it)-methotrexate / cytarabine and thalidomide - dexamethasone ( thal - dex ) for control of cns disease .
she remained stable for 6 months after relapse , while on lenalidomide and dexamethasone ( len - dex ) .
she developed progressive disease thereafter , with a rising serum free light chain ratio ( sflc ) and multiple fdg - avid pet lesions .
figure 1.cerebrospinal fluid ( csf ) cytological examination showed presence of abnormal plasma cells featuring enlarged and hyperchromatic nuclei , nuclear contour irregularity and occasional cells with binucleation .
the pc are of intermediate side scatter and are cd45 positive ( a ) , cd 38 brightly positive , cd 19 negative and cd 138 positive ( b and c ) .
they are also dimly positive for cd 28 and are cd 27 negative ( d ) ; this is a feature of aberrant pc .
cerebrospinal fluid ( csf ) cytological examination showed presence of abnormal plasma cells featuring enlarged and hyperchromatic nuclei , nuclear contour irregularity and occasional cells with binucleation .
the pc are of intermediate side scatter and are cd45 positive ( a ) , cd 38 brightly positive , cd 19 negative and cd 138 positive ( b and c ) .
they are also dimly positive for cd 28 and are cd 27 negative ( d ) ; this is a feature of aberrant pc .
we present a case of mm with isolated cns relapse and review the data related to outcomes of cns mm in the era of nas , biomarkers associated with cns mm and nas that show promise for activity in cns disease .
given the heterogeneity in neurologic manifestations of mm and incorporation of immunomodulators ( imids ) at the core of mm treatment in the last decade , an occurrence as rare as mm relapse with isolated cns involvement exhibits a potential for missed diagnosis .
some of the more commonly used nas include immunomodulators ( imids ) such as thalidomide , lenalidomide , pomalidomide and proteasome inhibitors ( ptdins ) such as bortezomib .
bortezomib - induced peripheral neuropathy ( bipn ) is a dose - limiting adverse effect and occurs in as many as 75% of patients treated with bortezomib .
though there is significant paucity of data related to risk factors for cns mm in the era of novel therapeutics , recently published reports suggest association with high risk features such as raised ldh and 2 m , igg paraprotein , high risk baseline genetic abnormalities and secondary plasma cell leukemia . in terms of disease outcome ,
nazanin m et al recently reported in their retrospective study involving 9 patients with cns - mm , who were treated with novel agents , to have a median os of 3.5 months which is not different in comparison with os in reports published prior to the era of novel drugs .
however , it is of note that commonly used imid / pi drugs have poor cns penetration except pomalidomide and marizomib which have shown promise in terms of cns penetration .. table 1 presents treatment and outcomes of cns myeloma .
table 1.treatment and outcomes of cns - mm in the era of nas.referencesnumber of patientsinitial treatmenttime to cns involvementcns treatmentosasct % ( pre / post)chen ci et al , 2013 3754% na:(16% pi , 38% imid)46% hdt20.6 mo70% na:(51% imid , 19% pi).81% it78% csi27% dtpace4.6 mo46%/5%paludo j et al , 2013 26 24 mo42% na:(23% ptdins , 19% imid).31% csi19% itc3 mo/23%erini k et al , 2015 31 ( 29 received treatment for cns - mm)100% na(74% pi , 11% imid , 16% both)29 mo62%
na:(41% pi , 17% imid , 3.5% both pi+imid).27.5% sc10% itc34% sc+itc3 mo3.5%nazanin m et al , 2015 9(7 received treatment)100% ptdins89% imid12.7 mo77% na:(55% pi , 22% imid).78% sc67% csi67% itc11% mtx3.5 mo55%/33%gangatharan sa et al , 2012 786% imid ( t)57% pi ( b)24 mo100% csi86% sc71% itc2 mo100%/lee d et al , 2013 1782% na ( t , l)47% ptdins ( b)36 mo41% na:[29% imid ( t),12% pi ( b)].71% csi47% itc18% sc4 mo100%/0%nieuwenhuizen l et al , 2007 109 17.8 mo51% itc45% sc43% csi2 mo/22%legend : cns = central nervous system ; os = overall survival ; itc = intra - thecal chemotherapy ; csi = cranio - spinal irradiation ; sc = systemic chemotherapy ; beam = [ bcnu ( carmustine ) , etoposide , ara - c ( cytarabine ) , melphalan ] ; na = novel agents ; dtpace = dexamethasone , thalidomide , cisplatin , doxorubicin , etoposide ; asct = autologous stem cell transplant ; b = bortezomib ; t = thalidomide ; l = lenalidomide ; mtx = methotrexate ; imid = immunomodulatory agents ; ptdins = proteasome inhibitor .
legend : cns = central nervous system ; os = overall survival ; itc = intra - thecal chemotherapy ; csi = cranio - spinal irradiation ; sc = systemic chemotherapy ; beam = [ bcnu ( carmustine ) , etoposide , ara - c ( cytarabine ) , melphalan ] ; na = novel agents ; dtpace = dexamethasone , thalidomide , cisplatin , doxorubicin , etoposide ; asct = autologous stem cell transplant ; b = bortezomib ; t = thalidomide ; l = lenalidomide ; mtx = methotrexate ; imid = immunomodulatory agents ; ptdins = proteasome inhibitor .
it remains a judgment call on the part of the treating physician to suspect , perform a comprehensive neurologic exam and assess the risk for cns relapse .
however , this entity carries a poor prognosis and may define the beginning of a terminal course and is , therefore , worth consideration even when the disease does not carry the biomarkers and genetic features associated with cns relapse .
further large - scale studies are needed to better understand the heterogeneity of cns - mm , biomarkers and genetic features that may demonstrate potential for prognostication and outcomes with ptdins / imid - based therapy with cns penetration .
due diligence needs to be paid to cns involvement in patients with mm , typically in the relapsed setting as that carries a dismal prognosis.cns mm has reportedly been associated with poor prognostic features such as high ldh , high b2 m and secondary plasma cell leukemia but statistical strength is still lacking.mm is associated with variable neurologic manifestations and it poses a clinical challenge to differentiate symptoms from disease versus those due to therapy.cns relapse must be considered in all patients with mm and appropriate radiologic and csf investigations be performed should symptoms persist , even in standard risk disease .
due diligence needs to be paid to cns involvement in patients with mm , typically in the relapsed setting as that carries a dismal prognosis .
cns mm has reportedly been associated with poor prognostic features such as high ldh , high b2 m and secondary plasma cell leukemia but statistical strength is still lacking .
mm is associated with variable neurologic manifestations and it poses a clinical challenge to differentiate symptoms from disease versus those due to therapy .
cns relapse must be considered in all patients with mm and appropriate radiologic and csf investigations be performed should symptoms persist , even in standard risk disease .
cwj treated the patient , conceived of the project and assisted with revision of manuscript . | ### Summary:
: abstractbackground : neuropathy is a common adverse effect of bortezomib . isolated central nervous system ( cns ) relapse in mm remains exceedingly rare and carries a dismal prognosis .
we present an unusual case of bortezomib related neuropathy masking a cns relapse of mm .
case presentation : a 57-year - old female was diagnosed with standard - risk mm with clinical and cytogenetic features not typically associated with cns involvement .
she was treated with 4 cycles of bortezomib / cyclophosphamide / dexamethasone ( vcd ) and achieved a vgpr , after which she underwent an autologous stem cell transplant ( asct ) followed by bortezomib maintenance .
six months after asct she developed symptoms suggestive of peripheral neuropathy which was attributed to bortezomib .
however the symptoms persisted despite discontinuation of bortezomib .
imaging and cerebrospinal fluid analysis subsequently confirmed a cns relapse .
discussion : cns involvement in mm ( cns - mm ) is uncommon and is considered an aggressive disease .
recently published literature has reported biomarkers with prognostic potential .
however , isolated cns relapse is even less common ; an event which carries a very poor prognosis . given the heterogeneous neurologic manifestations associated with mm , clinical suspicion may be masked by confounding factors such as bortezomib - based therapy .
the disease may further remain incognito if the patient does not exhibit any of the high risk features and biomarkers associated with cns involvement .
conclusion : in the era of proteasome inhibitor ( ptdins)/immunomodulator ( imid)-based therapy for mm which carries neurologic adverse effects , it is prudent to consider cns relapse early .
this case further highlights the need for more robust biomarkers to predict cns relapse and use of newer novel agents which demonstrate potential for cns penetration . |
<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:
: dental trauma among young people represents a widespread clinical and dental public health problem.1 among children younger than 6 , 18% of all somatic injuries affect the oral region.25 the prevalence of traumatic dental injuries among this age group has been reported to vary from 11% to 30%.69 in addition to causing pain , traumatic injuries to primary teeth can result in functional and esthetic problems10 and can affect the developing tooth germ.11,12 despite the significance of primary tooth injuries , few studies are available on the topic , and few epidemiological studies include primary teeth .
the purpose of the present study was to evaluate the type , prevalence , and treatment outcomes of primary tooth injuries among children referred to the department of pedodontics at the ankara university faculty of dentistry in turkey .
the study population consisted of all patients applying to the ankara university faculty of dentistry s department of pedodontics with a primary tooth injury over the 21-months period from 15 may 2007 to 15 february 2009 .
age , sex , time of injury , cause of injury , and number of teeth affected were recorded , and the type of trauma was identified according to andreasen s classification,2 as follows :
enamel fracture , including enamel chipping;enamel - dentin fracture , without pulpal involvement;enamel - dentin fracture , with pulpal involvement;root fracture;crown - root fracture , without pulpal involvement;crown - root fracture , with pulpal involvement;concussion;subluxation;intrusive luxation;extrusive luxation;lateral luxation;avulsion .
enamel fracture , including enamel chipping ; enamel - dentin fracture , without pulpal involvement ; enamel - dentin fracture , with pulpal involvement ; crown - root fracture , without pulpal involvement ; crown - root fracture , with pulpal involvement ; examination and treatment planning were performed by two of the authors .
a total of 99 teeth in 51 patients were treated by one of the authors ( v. a. ) .
during the 21-months period from 15 may 2007 to 15 february 2009 , 51 patients presented with trauma to 99 primary teeth . the age and sex distribution of patients
of the 51 patients , 31 were boys ( 60.8% ) , and 20 were girls ( 39.2% ) . in total , 21 patients ( 41.2% ) presented with 1 affected tooth ; 20 patients ( 39.2% ) , with 2 affected teeth ; and 10 patients ( 19.6% ) , with 3 or more affected teeth . with the exception of 1 patient ,
the most commonly affected tooth was the maxillary left central incisor ( 74.5% ) , followed by the maxillary right central incisor ( 64.7% ) .
the distribution , by month , of dental injuries in patients presenting at the clinic over the first 12 months of the study is given in table 3 .
the most common cause of injury was falling ( 80.4% ) , followed by collision ( 11.8% ) .
the distribution of injuries by patient age and injury type is shown in table 4 .
luxation injuries accounted for the majority of injuries ( 35/41 , 85.4% ) at age 2 , whereas hard tissue injuries accounted for the majority of injuries ( 12/22 , 56% ) at age 4 .
overall , the most common type of injury was lateral luxation ( 33.3% ) , followed by subluxation ( 14.1% ) .
the most common form of treatment was follow - up only ( 39/99 , 39.4% ) , followed by extraction ( 29/99 , 29.3% ) and root canal treatment ( 12/99 , 12.1% ) .
the majority of extracted teeth ( 19/29 ) were from patients aged 3 years and younger , with extraction required in 16 of these cases because the children s uncooperative behavior made it impossible to carry out any other treatment .
five of the 29 extracted teeth had root fractures , for which treatment is contraindicated.13 the remainder of the extracted teeth had wide radiolucent areas around the apical region and/or pathological root resorption resulting from the delay between the time of injury and presentation at the clinic for treatment . of the teeth receiving no treatment but followup ,
28.2% were intrusive luxations , none of which appeared to be a risk to their successors because of the direction of intrusion .
another 33.3% of teeth treated by follow - up only were lateral luxations , all of which were luxated less than 2 mm , had no occlusal interference , and were luxated in the palatinal direction , so they did not pose a risk to their successors .
all of these teeth were repositioned with appropriate pressure and splinted with 0.5 mm orthodontic wire and composite resin .
the splint time was 10 days for all teeth , with the exception of one case in which the splint time was increased to 14 days due to tooth mobility . all teeth receiving root canal treatment were followed up for a minimum of 1 year and , with the exception of one case , were judged to be clinically and radiographically successful .
no treatment but follow - up was applied to avulsed teeth , with the exception of one case in which a patient aged 3 years presented at the clinic 20 min after the time of injury .
the tooth had been stored in milk since the injury , and the injury had occurred inside the home , so the risk of contamination was considered minimal . given the circumstances , the decision was made to reimplant the tooth after obtaining informed consent from the parents .
the average follow - up period was 11 months , with the longest being 21 months and the shortest 3 months .
all cases followed up with for less than 6 months were extractions , and , with the exception of 1 re - implantation , all cases for which follow - up lasted from 6 months to 1 year were cases receiving no treatment but follow - up .
complications were observed during follow - up in 4 cases . in one of these cases ,
although the tooth re - erupted completely , pathological external root resorption was observed at 3 weeks following the injury , and the patient s age made it impossible to obtain cooperation ; therefore , the tooth had to be extracted .
in another case with complications during follow - up , a laterally luxated central incisor in a patient who applied to the clinic 1 day after injury was gently repositioned , and a semi - rigid splint constructed of 0.5 mm orthodontic wire and composite resin was applied .
the splint was removed after 1 week , and a root canal was performed using calcium hydroxide paste .
after 9 months , the tooth had to be extracted due to pathological root resorption that had started in the 7 month .
complications during follow - up also occurred in a patient with 2 crown fractures with pulpal involvement that received root canal treatment .
after 7 months of follow - up , the teeth were again exposed to serious crown trauma that made restoration impossible ; therefore , these teeth were also extracted .
only 16 of the 51 patients ( 31.4% ) presented at our clinic within 24 hours of injury , whereas 17 ( 33.3% ) presented between 24 hours and 10 days following injury and 18 ( 35.3% ) presented after 10 days .
the results of the present study generally conform to those of previous studies in the literature . almost all studies report a higher frequency of dental trauma among boys than girls.1,1418 in our study
, boys were found to be 1.5 times more likely to receive a dental injury than girls .
this higher incidence may be associated with differences in the types of games played by boys and girls . during the period
when children start to walk , especially between the ages of 1 and 2 years , poor muscle coordination results in an increased risk of trauma.4,6,19 andreasen reported another peak in injury at age 4 , when children s physical activity increases.2 in line with previous studies , our study found that 39.2% of traumatic injuries occurred between the ages of 1 and 2 and 23.5% at age 4 .
these findings highlight the need to inform parents and preschool teachers about traumatic injuries , since nearly all of the injuries at these ages occur at home or at preschool .
the majority of patients had more than 1 tooth injured by trauma ( 58.8% ) .
this finding stands in contrast to previous findings that show the majority of traumatic injury involves only 1 injured tooth . in a retrospective study of 543 children with traumatic injuries , rodriguez reported that 70.9% had only 1 injured tooth;1 skaare and jacobsen also reported a higher percentage of patients ( 58% ) with only 1 injured tooth,15 as did oliviera et al.16 differences in methodologies and sample sizes may account for the variation in the numbers of injured teeth reported by different studies . in the present study , except for 1 tooth ,
in line with previous studies,1,1416 the maxillary central incisors were found to be the most frequently injured teeth .
this is probably related to the position of the maxillary central incisors , which exposes them to direct traumatic force .
in contrast to the mandible , whose mobility tends to reduce the impact of force , the maxillary bone s fixed position in the skull prevents it from absorbing traumatic force , and , thus , the maxillary teeth are directly affected.20 our study found that most traumatic injuries to primary teeth ( 33.3% ) presented in the month of may .
this result is in agreement with saroglu and sonmez14 and perez et al,21 which indicates a seasonal variation in the distribution of traumatic injuries .
this variation may be due to a sudden increase in children s physical activity as temperatures increase in the springtime . in terms of etiology ,
our study found falls to be the most common cause of traumatic injury to primary dentition ( 80.4% ) .
this is in line with earlier findings14,15,22 and , as mentioned above , may be related to children s lack of muscle coordination during early childhood .
the next most frequent cause of traumatic injury to primary dentition ( 11.8% ) was collisions .
this finding is in line with most previous studies,6,14,23,24 although some authors have found hard tissue injuries to be the most common type of injury to primary dentition.7,25 the more frequent occurrence of periodontal tissue injury may be explained by the more resilient character of bone in young children in comparison to young adults . in our study , the rate of hard tissue injuries increased with age , whereas the rate of luxation injuries decreased ( table 4 ) . although some exceptions were observed after age 4 , the number of cases is insufficient to be conclusive .
the most common treatment for injured primary teeth was follow - up only ( 39.4% ) .
this finding is similar to that of previous studies.21,26,28 according to 2007 guidelines for traumatic injuries,13 follow - up for re - eruption is recommended for intruded primary teeth if the apex is displaced through or toward the labial bone plate .
all the teeth with intrusive luxations in the present study met these criteria , and all re - erupted during follow - up periods of between 3 weeks and 2 months .
this tooth had intruded 4 mm into the alveolar bone , compared to intrusion of less than 3 mm for all the other teeth . in view of this finding , one might conclude that the prognosis for intruded primary teeth is dependent upon the degree of intrusion , with teeth intruded less than 3 mm capable of spontaneous re - eruption and healing without any treatment .
although guidelines do not recommend reimplanting primary teeth,13 some authors have reported successful cases of reimplantation.29 in deciding whether to attempt reimplantation , the benefits as well as risks to the patient should be weighed carefully , and the tooth should be followed up with closely . in our case ,
reimplantation was considered appropriate because of the short time between injury and presentation and the fact that the tooth had been stored in milk following injury .
additionally , a close follow - up of the patient was possible . at 7 months of follow - up ,
both clinical and radiographic examination indicated the treatment to be successful , and close follow - up is continuing .
several recent studies have been conducted on the prevalence of dental trauma among children in ankara , turkey .
a study by saroglu and sonmez14 examining dental trauma to both primary and permanent dentition among children presenting at the ankara university faculty of dentistry s department of pedodontics described 34 cases of traumatic primary tooth injury treated during an 18 months period ( 1999 october to 2001 april ) .
another prevalence study by altay and gungor26 conducted at hacettepe university , a university dental clinic in ankara , described 72 cases of traumatic injury to primary teeth treated over a 4 years period ( 19962000 ) .
one can conclude from these studies and the present study that the incidence of traumatic injury to primary dentition in ankara has increased in recent years .
it is also possible that the increase in patients presenting with traumatic injury to a primary tooth may be related to changes in government health policy and increases in the number of patients applying to university hospitals instead of other private or state hospitals .
findings from the present study indicate that in the absence of acute symptoms , parents tend not to apply to a dental clinic for children s dental injuries , especially those affecting primary teeth . however , the finding of periapical radiolucency among 39.1% of patients who did not apply to a clinic until at least 10 days after injury highlights the importance of immediate examination and treatment of traumatic injuries to primary teeth .
this finding also indicates the importance of informing the public , especially parents and teachers , about primary tooth injuries and their consequences . | ### Summary:
: objectives : the aim of the present study was to evaluate the type and prevalence of primary tooth injuries , as well as their treatment and treatment outcomes , among children referred to the department of pedodontics at the ankara university faculty of dentistry in turkey.methods:the study population consisted of patients applying to the department with a primary tooth injury over a period of 21 months .
fifty - one patients presented with trauma to 99 primary teeth .
clinical and radiographic examinations were conducted on each patient .
age , sex , time , cause of injury , and number of teeth affected were recorded , and the type of trauma was identified according to andreasen s classification .
the teeth were treated by one of the authors.results:the majority of trauma occurred between the ages of 2 and 4 .
the most common type of injury was lateral luxation ( 33.3% ) .
most injuries ( 33.3% ) presented during may . the most common form of treatment was follow - up only ( 39.4% ) , followed by extraction ( 29.3% ) and root canal treatment ( 12.1% ) .
the average follow - up period was 11 months . during the follow - up period , complications were observed in 4 teeth.conclusions:the study results show that in the absence of acute symptoms , parents tend not to apply to a dental clinic for children s injuries .
this finding highlights the importance of informing the public about primary tooth injuries and their consequences . |
<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 simultaneous measurement of expression levels of tens of
thousands of genes in a biological sample enabled by dna
microarray technology has provided a new and powerful way to
characterize the molecular basis of diseases such as cancer
[ 1 , 2 ] . in the past decade , mrna expression profiles of tumor
tissues have been successfully used to distinguish tumor types or
subtypes [ 35 ] . they also appear to hold great promise as a
method for predicting clinical outcomes [ 68 ] .
for example ,
gene expression profiles have been used to classify lung
adenocarcinoma into subgroups that correlated with the degree of
tumor differentiation as well as patient survival .
gene expression profile analysis initially emphasized the
identification of groups of genes that are differentially
regulated in different experimental conditions or patient samples .
coexpression across a variety of samples implied coregulation or
similar function [ 10 , 11 ] .
an approach complementary to this
gene - centered view is to take a sample - centered
perspective in which one treats the genome - wide profiles of each
sample as the entities to be classified with respect to their gene
expression patterns .
the goal here is to assign samples ( rather
than genes ) to groups based on the high - dimensional molecular
signature determined by the thousands of individual gene
expression values . while the gene - centered perspective is useful
for understanding the molecular pathways in which individual genes
are involved , the sample - centered view is more relevant for
biological and clinical questions , such as in the study of the
developmental and pathogenetic relationship between tissues as a
whole [ 12 , 13 ] or the identification of prognostic or
diagnostic signatures of tumors based on entire gene expression
profile portraits [ 4 , 1419 ] .
the notion of molecular portraits has gained importance as
gene expression profiles for increasingly large numbers of samples
or conditions ( eg , experimental variables , patients , treatment
groups , etc ) have become available [ 18 , 20 , 21 ] .
however , the
analysis of large numbers of gene expression profiles as
integrated entities poses a challenge in terms of how to best
organize and graphically present the high - dimensional data without
loss of the notion of an individual profile as an independent
entity .
it would be desirable to capture the global picture of
sample clusters within one visual representation while
simultaneously presenting the specific expression pattern within
each individual sample , and hence , simultaneously allowing
gene - specific analysis .
current representations , such as the widely used heat maps in
two - way hierarchical clustering [ 22 , 23 ] or coordinate
systems in principal component analysis ( pca ) , multidimensional
scaling ( mds ) and their variants [ 2426 ] , compress the
expression profile information of a sample into a single quantity ,
such as a scalar value for the distance ( dissimilarity ) between
the sample , a branch in a dendrogram , a narrow column in a
heat - map , or a point in reduced - dimensional space .
such aggregate
displays discard possibly relevant information immanent in the
complex , higher - order ( system - level ) genome - wide expression
pattern .
this intrinsic but hidden information reflects the
collective behavior of genes orchestrated by genome - scale gene
regulatory networks that govern cell behavior .
as
pathology and radiology teach us , the implicit visual cues present
within a complex image ( eg , histological section , radiograph )
can not be reduced to a set of numerical variables without loss of
system - level information content .
thus , it is possible that some
irreducible information contained within high - dimensional gene
profiles of patient or experimental samples may be lost in current
clustering and representation methods . in the absence of specific questions or hypotheses
, it would
therefore be desirable to be able to directly compare microarray
results of individual tumor samples with their complete
feature - richness in the same holistic
way as pathologists
compare histological tumor samples , namely , based on human gestalt perception .
in contrast to histological
patterns , the thousands of expression values in a microarray
measurement are too dense and irregular to be directly interpreted
in a holistic manner .
hence , they must be presented in a form
appropriate for human pattern recognition without discarding the
global , higher - order information .
self - organizing maps ( soms ) have the capacity to display
information - rich diagrams . in the case of microarray data they can
present individual samples as an entity and , at the same time ,
display high - resolution patterns within the transcriptome .
a self - organizing map is a neural network algorithm for
unsupervised machine learning with a strong visualization
capability . in brief
, it assigns a set of n input
objects ( eg , genes ) to a number k ( k < n ) rectangular or
hexagonal tiles ( som nodes ) , each of which represents a
cluster of objects ( genes ) , arranged so as to form a coherent
pattern within a two - dimensional mosaic ( som grid ) .
the
patterns arise because the distances between the tiles on the
mosaic are a function of the similarity between the gene clusters
that the tiles represent , with most similar clusters being
adjacent to each other in the mosaic .
early applications of soms for visualization of gene expression
profiles emphasized the gene - centered perspective ( clustering of
genes ) and used each tile to represent one cluster of genes in
order to identify gene clusters with interesting expression
patterns or to link them to gene functions .
as in
k - means clustering , the number of clusters k is
chosen in this approach to approximate the number of expected
number of gene clusters , for example , k = 12 on a 3 4 =
12 node grid .
other studies used som in the
sample - centered mode to map individual tumor samples onto the som
grid and thereby classify tumor samples into a small number of
diagnostic or prognostic groups [ 32 , 33 ] . in both cases , an
entire experiment consisting of multiple samples ( expression
profiles )
was represented by one single som grid , and the
sample - specific visualization capabilities of som were not
explored . in another study , soms were used in the
gene - centered mode to analyze lymphoma samples , but the number of
clusters ( k = 22 14 ) was much larger than the expected
number of biological clusters .
the characteristic som mosaics contained coherent patterns
generated by the colored tiles ordered so as to reflect the
clustered gene expression profile of the individual samples
.
but while this approach used the visual representation
of som , it still focused on finding subset of genes for
classifying tumors . in these cases
the som maps were used as
graphical representation mostly to illustrate a particular
algorithm of analysis , much as dendrograms serve to give evidence
of hierarchical clustering , but are not actually read by the human
eye to obtain specific information .
instead , we propose that som
displays can be specifically treated as new , complex objects for a
next level analysis , namely , visual gestalt recognition .
thus , we
do not use computer algorithm in the sense of artificial
intelligence , but more as intelligence enhancement for the
human brain in the holistic comparison of the transcriptomes . to enable such an integrative analysis based on visualization of
each tumor sample as a unique and complex molecular portrait
, we
adapted gedi a som - based tool developed for visualizing the
dynamics of genome - wide gene expression profiles to
represent static microarray samples as two - dimensional
high - resolution som mosaics .
using published gene expression
profiles from a large set of lung tumor samples , we offer
a first assessment of the usefulness of this type of holistic
visual analysis of tumor gene expression profiles .
these studies
reveal that human gestalt perception can lead to discovery of
novel biological features without a preconceived hypothesis , and
uncover new relationships between lung tumor subtypes that had
previously escaped the analysis using conventional algorithmic
classification techniques [ 5 , 36 ] .
starting from an n m matrix of data from the analysis of
n genes across m samples ( mrna expression profiles ) , gedi
transforms each sample 's expression profile into a map that
contains a visually recognizable color pattern , referred to as a
gedi map .
these maps are mosaics generated by
self - organizing maps ( soms ) ( see materials and methods ) .
in brief ,
this was achieved by ( i ) a moderate reduction of
dimensionality with respect to the genes , from n genes into k
gene clusters , which are represented by metagenes , and ( ii ) by
a spatial reordering of these metagenes onto a two - dimensional
space represented by an a - by - b grid ( with a b = k )
using som .
the expression values of the
metagenes are the centroids of the corresponding clusters
and are displayed as one of the k colored
since the soms assign the same metagene to
the same tile for each mosaic , they can be compared to each other .
moreover , since metagenes that exhibit a similar behavior with
respect to the m samples are placed next or close to each other
on the mosaic , the tiles collectively create a coherent pattern on
each mosaic that is characteristic for each sample [ 29 , 38 ] .
importantly , in contrast to conventional cluster analysis using
k - means or som , where typically k < 30 clusters , here
k is many folds higher than the expected or desired number of
biologically significant clusters , and hence , each of the k
metagenes can be viewed as representing a
minicluster of just
a few genes ( with a typical median of around 10 genes ) .
a
minicluster is thus not meant to represent some biologically
relevant gene cluster . instead , the som algorithm is used to
pixelate the expression profile into k pixels and
rearrange them , which is why k is required to be high :
typically , k = 100 s to 1000 s [ 12 , 13 ] .
these
miniclusters consequently contain an order of magnitude fewer
genes than in conventional gene clustering and are hence
more homogeneous , warranting the representation as a metagene .
accordingly , the patterns formed by the metagenes on a gedi map
will be referred to as metapattern .
based on the characteristic visual metapatterns , gedi maps allow
the direct comparison of the biological samples , as well as
immediate identification of biologically interesting groups of
genes .
the genome - wide gene expression profiles of 25 samples of normal
lung tissue ( lung ) and different pulmonary tumors ,
carcinoid ( car ) , squamous cell carcinoma ( sq ) ,
and small - cell cancer ( smc ) , were visualized as
25 gedi maps , each consisting of a 31-by-30 mosaic , representing
930 miniclusters .
discrete differences in patterns of gene
expression between normal lung and tumor samples are immediately
detected upon visual inspection of the gedi maps
( figure 1 ) .
each sample exhibits characteristic
spatial and color patterns , reflecting genome - wide transcriptional
behavior of the respective tissue sample .
the visual patterns of
the gedi maps of these different tissue samples remained distinct
when the analysis was performed with a wide range of som
parameters and the soms were run to convergence ( not
shown ) .
inspection of gedi maps allows a straightforward classification of
the samples into subgroups without the aid of a clustering
algorithm , but simply based on the visual differences in the
metapatterns .
samples grouped together with members of the same
category , with the exception of one outlier , a small - cell lung
cancer sample , smc6 whose gedi map looked different
( figure 1 ) . as previously demonstrated ,
hierarchical cluster analysis reliably arranged these lung tumor
samples into distinct clusters which corresponded well to the
different clusters identified using gedi ( figure 1 ) .
a known drawback of hierarchical clustering is that the linear
arrangement of the clustered objects ( samples ) at the terminal
branches of the dendrogram can be presented in multiple ways
( orderings ) .
this can make the unbiased global assessment of
intersample similarity across all the samples difficult .
although
this arbitrariness can be eliminated by using a one - dimensional
som , k - means clustering , or other optimization algorithm to
achieve some objective branch ordering [ 39 , 40 ] , this method
is not often used . by contrast , because there is no a priori
clustering structure in gedi , sample clustering is directly
obvious and robust and avoids bias suggestion of relatedness a
known problem with hierarchical clustering .
another shortcoming of hierarchical clustering is that the
hierarchical relationship displayed in the dendrograms does not
necessarily have a biological meaning .
for example , hierarchical
clustering forces the randomly permuted data into a tree structure
with similar overall structure ( albeit with a higher distance
score between the branches ) even though the samples have now
random attributes and have no meaningful relation
( figure 2 ) .
in contrast , in this case the gedi maps
immediately reveal the poor quality of clustering : the samples
that were clustered together by hierarchical clustering do not
exhibit any consistent global pattern ( figure 2 ) .
therefore , gedi also provides a first - line sample - centered quality
control for traditional clustering methods .
because gedi maps provide a global view of the gene expression
profiles of each sample , they immediately present an explanation
for why a particular sample behaves as an outlier ( when sample
diagnosis is known ) and which genes account for that behavior . for
example , the dramatic difference between the gedi map of an
outlier , smc6 ( figure 1 ) , relative to samples within
the cluster of nominal small - cell lung cancers immediately reveals
that smc6 deviates from the other small - cell carcinomas and the
different pattern of tiles explains why .
in addition to visually comparing gedi maps as individual
entities , one can extract the numerical centroid values yk
in sample j of each metagene k to analyze gedi
maps quantitatively . by utilizing the metagenes instead of the
real genes to characterize a transcriptome ,
the complexity is
reduced , in our case from the original data matrix n m = 12562 25 to 930 25 . to evaluate the fidelity of gedi mosaic patterns in
representing the expression profiles established by all the genes
,
we calculated the correlation coefficients rjk for every pair
of samples ( j , k ) using either ( 1 ) the expression data for all
of the individual genes or ( 2 ) the metagenes .
if the gedi mosaic
patterns of metagenes faithfully represent the genome - wide gene
expression profiles , the correlation coefficients for all sample
pairs calculated in these two ways will be similar .
in fact , the
gedi patterns preserved the correlation between samples obtained
from the real gene expression data ( figures 3(a ) ,
3(b ) ) .
the correlation of the values and the ranks of
rjk between the two methods were 0.909 and 0.960 ,
respectively .
interestingly , the values of the correlation coefficients ( profile
similarity between samples ) calculated from metagenes spanned a
considerably broader range than those from the real gene
expression dataset , as apparent in the histograms of the
correlation values ( figures 3(c ) , 3(d ) ) .
color contrast of the
correlation matrix color map ( figure 3(b ) versus
3(a ) ) .
thus , it appears that the discriminating power of
this technique using metagenes may be increased relative to
standard microarray analysis .
the differences in the average
correlation between sample pairs within the same tissue groups
( intratissue pairs ) and across tissue groups ( intertissue
pairs ) were considerably larger when metagenes ( 0.127 , 95%
confidence interval : 0.109 to 0.145 ) were used for calculating the
correlation , compared to when real genes ( 0.069 , 95% confidence
interval : 0.058 to 0.080 ) are used ( figure 3(e ) ) .
it
remains to be determined statistically in extended data sets
whether metagene - based analysis consistently has a greater
discriminating power by using larger test sets of tissue samples
for patient groups with established diagnosis . in summary , the gedi maps based on metagenes faithfully
recapitulate gene expression profiles of the entire gene dataset
despite dimension reduction .
thus , the visual patterns capture the
real similarity relationships among samples with a high fidelity . to further validate how well metapatterns can represent the
transcriptome
second - level gedi analysis to
categorize gedi maps automatically using the ( n = 930 metagenes
, we also performed a pca on the original gene data
matrix ( with sample columns as the objects and gene rows as
the attributes ) .
the second - level gedi analysis differed from
the first - level gedi analysis performed on the ( n = 12562 real
genes m = 25 samples ) matrix in that the objects of
clustering were the samples but not genes , and thus a smaller som
grid was used .
given the discriminatory power of the metagenes ,
using them as input variables may improve the quality of sample
clustering .
the 25 samples were assigned to a 5 5 som grid according
to their metagene expression profiles . in the resulting
second - level gedi map
, the tissue samples ( the first - level gedi
maps ) of the same diagnosis were grouped within the same
neighborhood of the map ( figure 4(a ) ) .
the map
distances from each tumor - specific sample cluster to that of
normal lung ( lung ) were roughly similar , while among the
tumors , the carcinoid ( car ) and squamous cell carcinoma
( sq ) samples were most distant from each other , with
small - cell lung cancer ( smc ) in between .
interestingly , the spatial distribution of these samples in the
two - dimensional second - level map was very closely mirrored in the
pca in which the samples were projected on the plane spanned by
the two first eigenvectors ( figure 4(b ) ) .
there was
good agreement even with respect to the relative position of the
individual samples within each tumor and tissue type ( figure
4(a ) versus 4(b ) ) .
importantly , such information revealed by the 2d sample plane , be
it the som grid of the second - level gedi or the pca plane , can be
directly read from the metapatterns of the gedi maps .
visual
inspection of the gedi maps readily confirms the notion that sq2
displays significant feature similarity to the smc samples based
on the fine structure of the patterns of upregulated genes .
specifically , the gedi metapattern showed that sq2 lacked the
extension of the red areas ( highly expressed genes ) from the right
half into the upper - left quadrant of the gedi map that is
characteristic for the other sq samples
( figure 4 ) .
interestingly , this group of metagenes
that was not expressed in sq2 contained multiple keratin - related
genes , consistent with the squamous cell origin of these tumors .
without the gedi maps , the samples would be represented by dots in
the pca which would be identified solely by their position in the
abstract eigenvector space .
thus , gedi allows the rapid toggling
between gene - centered and sample - centered perspectives ,
which is an important feature for an integrative yet gene - specific
analysis .
like small - cell carcinoma , lung carcinoid tumors are also
classified as ( low - grade ) neuroendocrine tumors , while
squamous carcinoma appears to be unrelated to this group .
however ,
in both hierarchical clustering as well as in pca , smc
was closer to sq than to car ( figures
1 and 4 ) , which is consistent with the idea
that small - cell lung carcinoma may have an epithelial origin
, but competes with the notion of the common
neuroendocrine property of smc and car .
to
examine this dualism we used gedi to analyze the relationship
between these three pulmonary tumors and normal lung to compare
not only by how much but also how each of these
tumors qualitatively differed from normal lung tissue and
from each other .
the gedi software environment allows the user to
easily perform algebraic operations on whole mosaic patterns based
on metagene expression values , and for instance to calculate
average mosaics from a group of samples with the same
diagnosis or difference mosaics to reveal differential
expression patterns between two samples ( or averages of two
groups ) .
( figure 5(a ) ) by subtracting the averaged gedi maps of
normal lung samples from that of smc , car , or
sq , respectively .
the red areas in the difference maps
indicate genes that were upregulated in these tumors compared to
normal lung tissue .
the outlined areas on the maps represent four
islands ( labeled a , b , c , d in figure 5(a ) )
that contain the top 5% differentially expressed genes in
smc versus lung .
these studies revealed that smc and sq share a
set of features , representing a number of genes located within
regions a
this is consistent with the vicinity of
these two tumors in the dendrogram ( figure 1 ) and in
the pca sample plane ( figure 4 ) ; it also is in line
with the proposed epithelial origin of small - cell lung cancer
.
c included growth - related genes
( involved in cell proliferation , cell cycle , dna replication ,
etc ) .
such functional enrichment of genes in the gene islands
underscores the biological meaning of pattern features in gedi
maps .
interestingly , the smc samples while globally close
to sq samples , shared with the car samples the
island d , which contained neuroendocrine - related genes ( involved
in synaptic vesicle , neuromuscular physiological process , etc ) ,
consistent with the neuroendocrine nature of small - cell lung
carcinoma .
this example illustrates how gedi can extract relationship
features that are not revealed by traditional hierarchical
clustering or any reduction of sample comparisons to a similarity
metric . specifically ,
while three islands ( a c ) that
represent the regions of metagenes upregulated in smc
compared to normal lung also were found in sq ( a , b ,
c ) , they were absent from car .
conversely , the island
d that was enriched for the neuroendocrine genes was
overexpressed in car but not in sq .
thus , the
gedi analysis exposed a novel facet of relationship between the
samples with respect to these signature gene clusters :
smc appears to be the union set of the sets of
car and sq ( figure 5(b ) ) , sharing
the gene cluster d with car and the clusters a , b ,
and c with sq . with respect to these growth - related
gene islands
thus , despite the overall higher
similarity between smc and sq , when considering
the subfeature d with the neuroendocrine genes , smc was
closer to car than to sq .
such information on a
qualitative relationship is lost in conventional clustering
dendrograms that reduce relationships to a numerical similarity
between two samples . without an a priori hypothesis ,
such qualitative relationships are almost impossible to identify
in the widely used heat maps , but they immediately spring to eye
in the differential gedi maps .
genome - scale gene expression profiles are not simply
high - dimensional sets of variables that provide an opportunity for
multivariate statistical analysis . instead , they are the
biological manifestation of the constrained dynamics of the
underlying complex and hierarchical gene regulatory networks that
govern developmental potentials of cells and tissues .
tumors arise from mutational rewiring of this molecular network
and therefore , display specific , coordinated deviations from the
normal transcriptome patterns . to visualize coherent , genome - scale
alterations of the transcriptome structure , we used here an
integrative visual representation for gene expression profiles .
as
a test example we analyzed expression profiles of three lung tumor
samples as a case study .
we show that by delegating the actual
process of pattern recognition to human gestalt perception in the
format of som - based gedi mosaics , interesting features in the
relationship between tumor types can be revealed .
specifically , we
found that with respect to pathological deviation from normal gene
expression , small - cell carcinoma represents the union set of
squamous cell carcinoma and carcinoids .
such information on
higher - order transcriptome changes , which may be useful for
understanding developmental relationships and differences in drug
responsiveness between tumor types , spring to eye in the gedi
maps , but would not have been revealed in conventional algorithms
without explicitly asking the appropriate question .
microarray - based molecular profiles are increasingly used to
capture characteristic high - dimensional molecular
most existing
methods reduce complex relationships to a numerical value ,
typically , a distance metric or a visual distance between points
in a reduced dimension space .
while this is useful for explicitly
extracting specific information , these methods may lose
potentially useful , unanticipated information inherent in the
high - dimensional expression profiles , such as particular
higher - order patterns of expression .
similarly , even the search
for a multigene signatures instead of a single marker
gene to improve discrimination between diagnostic groups may miss
some of the distributed ( holistic ) information in the
profiles . in fact , maximal accuracy of multiclass tumor
classification may require that the predictor utilizes all the
genes .
the gedi visualization software was developed to circumvent the
problem of discarding implicit , potentially irreducible
information inherent in genome - wide expression profiles in the
absence of a specific hypothesis .
it provides the opportunity for
a holistic , yet molecular exploration of a set of gene expression
profiles ( or other high - dimensional data sets ) that can be used to
test existing tissue - level biological hypotheses or
establish new ones .
although gedi uses a som algorithm at its
core , it differs fundamentally from the traditional use of som to
find biologically meaningful clusters [ 30 , 32 , 33 , 38 ] .
the
metagenes in gedi are miniclusters that are smaller by an order of
magnitude than the explicitly predefined clusters in the
conventional cluster analysis , hence they are very tight and of
high quality .
the identification of biological clusters is not the
result of the clustering algorithm per se , but is
achieved at a later stage of analysis , namely , by visual
inspection and gestalt perception of the metapatterns that emerge
from the som - generated metagenes .
hence , ambiguities in clustering
of samples are not built into the algorithm , but are subject to
direct and interactive analysis by the interpreter .
gedi provides several technical benefits relative to existing
high - dimensional data analysis methods .
( a ) by presenting metapatterns , gedi maps provide a visual engram
of each sample 's particular molecular profile , and hence ,
establish a molecular portrait in the very sense of the word , with
a particular visual identity for each sample ( eg , tumor type ,
patient , treatment condition ) .
( b ) although classification of samples into groups is achieved by
human gestalt perception of the metapatterns , it can be supported
by an algorithmic approach applied on the metagenes .
( c ) the direct visual monitoring of the portrait of a sample
allows gedi to intercept algorithmic idiosyncrasies , such as the
dependence of the branching structure of dendrograms on the
particular tree - building algorithm used in hierarchical
clustering .
( d ) despite a moderate dimension reduction , gedi preserves most of
the information richness of entire molecular portraits , allowing
detailed , multivariate explorative comparisons between samples .
this in turn can help define qualitative differences ( in addition
to measuring quantitative dissimilarity between samples ) that may
provide additional biological information on the relationships
between samples .
( e ) gedi allows the rapid and seamless switching between an integrative ,
sample - oriented analysis and the more traditional gene - centered
analysis .
this is facilitated by the interactive user interface
that permits retrieval of genes that contribute to metapattern
features of interest .
( f ) finally , using gedi to compare the samples and relate them to each other
does not require specific knowledge of the underlying algorithm ,
and thus is an intuitive tool for nonbioinformaticians , such as
pathologists and clinicians that will increasingly confront
microarray analysis .
this is specifically relevant for the
explanation of anomalies in cluster analysis , such as outlier
samples .
the reason for misclassification is usually directly
evident in the gedi map and does not require familiarity with the
details of the algorithm .
although biologists have begun to use gedi
maps [ 12 , 13 , 44 ] to ask biological questions , further
systematic elucidation of its application , notably , the choice of
optimal size of miniclusters is needed .
future use of gedi in
studies of the genome - scale molecular signature of both normal and
disease samples will ultimately help assess the true value of a
holistic interpretation of molecular profiles that systems
biology is advocating . | ### Summary:
: genome - wide gene expression profile studies encompass increasingly large number of samples , posing a challenge to their presentation and interpretation without losing the notion that each transcriptome constitutes a complex biological entity .
much like pathologists who visually analyze information - rich histological sections as a whole , we propose here an integrative approach .
we use a self - organizing maps -based software , the gene expression dynamics inspector ( gedi ) to analyze gene expression profiles of various lung tumors .
gedi allows the comparison of tumor profiles based on direct visual detection of transcriptome patterns .
such intuitive gestalt perception promotes the discovery of interesting relationships in the absence of an existing hypothesis .
we uncovered qualitative relationships between squamous cell tumors , small - cell tumors , and carcinoid tumor that would have escaped existing algorithmic classifications .
these results suggest that gedi may be a valuable explorative tool that combines global and gene - centered analyses of molecular profiles from large - scale microarray experiments . |
<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:
: brain abscesses results from a focal suppurative process within the brain parenchyma , and brain abscesses account for 1 - 8% of all intracranial space - occupying lesions .
brain abscesses remain a potentially fatal infection despite the availability of improved diagnostic imaging modalities and recent advancements in the management of brain abscess , with a 8 - 25% mortality rate [ 1 , 2 ] .
enterococci are indigenous to the normal intestinal flora of humans , and most clinical infections are caused by either enterococcus faecalis or e. faecium .
e. avium , formerly known as " group q streptococcus " , is one of the 23 known enterococcus species and is pathogenic to humans [ 4 , 5 ] .
however , e. avium is rarely associated with brain abscess . here , we report of a patient presenting with a brain abscess , from which e. avium was isolated as the only pathogen
. additionally , we identified and reviewed the english language articles on similar previous cases published between 1967 and 2012 , using the following keywords : " brain abscess " , " group q streptococcus " , and " enterococcus avium " .
a 48-year - old man with a 13-day history of headache and right otalgia was admitted to our tertiary medical center .
he was diagnosed with type 2 diabetes mellitus 3 years earlier and was thereafter treated with oral hypoglycemic agents up until the current presentation . the patient had chronic suppurative otitis media for several years .
physical examination showed that his verbal output was reduced and his neurologic status was 11 on the glasgow coma scale .
the patient 's temperature was 36.8 , blood pressure was 140/100 mmhg , and pulse was 80 beats / min . otoscopic evaluation revealed the exudation of fresh pus from the right ear .
laboratory studies revealed an elevated leukocyte count of 18,500/mm and an elevated c - reactive protein level of 18.9 mg / dl .
serological tests were negative for human immunodeficiency virus ( hiv ) , hepatitis b , and hepatitis c. brain magnetic resonance imaging ( mri ) showed the presence of a 3.5-cm , rim - like enhancing lesion in the right temporoparietal lobe with perilesional edema ( fig .
obliteration of the right mastoid air cells with sclerotic changes was noted , and its communication to the right mastoid was suspected .
the patient underwent stereotactic aspiration of the brain abscess and treated with parenteral antibiotics , including ceftriaxone ( 2 g every 12 hours ) and metronidazole ( 500 mg every 6 hours ) .
elective surgery was scheduled , but a follow - up computed tomography ( ct ) scan showed significant decreases in the extent of brain abscess due to abscess drainage through the communication site of the right ear .
species identification and antimicrobial susceptibilities of e. avium were determined using the microscan pos breakpoint combo panel type 28 ( siemens , ca , usa ) .
antibiotic susceptibility testing of the isolates showed that the pathogen was susceptible to penicillin , ampicillin , imipenem , glycopeptides , fluoroquinolones , and high level of aminoglycosides .
parenteral antibiotic therapy consisting of ceftriaxone , metronidazole , and ampicillin was continued for 4 weeks .
after parenteral antibiotic therapy , the patient 's neurologic deficits improved , and he was discharged in a stable condition with oral antibiotics .
oral antibiotic therapy comprising amoxicillin ( 500 mg every 8 hour ) and levofloxacin ( 750 mg every 24 hours ) was continued for 8 weeks . compared the images of the initial mri and the follow - up ct performed 1 month later , the abscess seemed to be completely resolved .
three months after diagnosis , the patient was full recovered without any residual neurologic deficits .
enterococci are generally regarded as the normal intestinal flora . over the past 2 decades , however , enterococci have been identified as one group of pathogens responsible for several nosocomial infections ; e. faecalis and e. faecium account for up to 90% of the responsible clinical isolates [ 6 , 7 ] . in a previous study ,
streptococci were identified as the most common bacteria identified in cultures in patients with brain abscesses , with e. faecalis and e. faecium accounting for only 5% of all isolates [ 1 , 8 ] .
thus far , only 6 cases of brain abscesses caused e. avium have been reported , including those reported in the present study [ 9 - 13 ] .
the main characteristics of these cases are summarized in table 1 . to the best of our knowledge ,
this case report is the first to report a brain abscess caused by e. avium in korea .
the pathogenic mechanism of brain abscess formation involves either contiguous spread from the focus of infection , hematogenous dissemination to the brain from a distant focus , or head trauma . in most cases ,
the brain abscess was occured due to contiguous spread from the middle ear , mastoid cells , or paranasal sinuses .
carpenter et al . reported that more than 40% of brain abscesses in adult patients are otogenic in origin . in their study , abscesses were located in the temporal lobe ( 54% of patients ) , cerebellum ( 44% ) , or both locations ( 2% ) . in our case review of brain abscess due to e. avium ( table 1 ) , we found that 5 of 6 patients presented with chronic otitis media , and only 1 patient , who was previously diagnosed with astrocytoma , did not present with otitis media .
these findings suggest that brain abscesses caused by e. avium infection are predominantly otogenic in origin .
treatment of brain abscess is.done by.a team approach ; adequate abscess drainage and appropriate antimicrobial therapy are most important for proper treatment . in patients with bacterial brain abscess , intravenous antimicrobials
shorter courses ( 3.4 weeks ) of parenteral therapy may be adequate for patients who have undergone surgical excision of the abscess . in the present case , follow - up ct showed a significant decrease in the extent of brain abscess , owing to abscess drainage through the communication site .
attending physicians need to consider e. avium infection in such cases , so that effective therapy can be initiated as soon as possible . in 1984 , collins et al .
successfully proposed the renaming of " streptococcus avium " to " enterococcus avium " due to the findings of various dna - dna and dna - ribosomal rna studies . although e. faecalis and e. faecium are the 2 most common species responsible for enterococcal infections , our findings and other reports demonstrate an emerging trend of e. avium infection in humans . only a few clinical manifestations caused by e. avium
have been reported thus far , including bacteremia , endocarditis , osteomyelitis , and splenic abscess [ 4 , 16 - 18 ] .
however , only 1 patient with e. avium brain abscess was in an immunocompromised state at diagnosis ( table 1 , case 2 ) .
virulence traits are believed to permeate enterococcus species to various degrees , thereby enhancing their disease - causing abilities .
however , factors that influence the virulence potential of e. avium are not well understood .
recently , na et al . suggested that e. avium seems to be more virulent than e. gallinarum and e. casseliflavus , but less virulent than e. faecium .
although e. avium is not commonly associated with brain abscesses , it should be considered as an etiological agent in the future , especially in patients diagnosed with chronic otitis media . | ### Summary:
: brain abscesses can be highly lethal if appropriate treatment is not administered , and reports of such an abscess caused by enterococcus avium are very rare . here
, we report a case of a 48-year - old man presenting with chronic otitis media .
he initially presented with a headache and right otalgia . an otoscopic evaluation performed on the day of admission showed exudation of fresh pus from the right ear .
brain magnetic resonance imaging demonstrated a hypodense area in the right temporoparietal lobe , suggestive of a brain abscess .
a culturing of the ear discharge and brain abscess aspirate proved of e. avium infection .
following stereotactic aspiration of the brain abscess and proper antimicrobial treatment , the patient recovered completely . in this report
, we also review and discuss the available medical literature on previous cases of e. avium infection associated with brain abscess . |
<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:
: one of the most common mechanical problems in implant prostheses is the joint loosening and fracture that occur in the screw joint portion between the implant fixture and the abutment.1,2 joint loosening , along with the mechanical failure of the implant prosthesis , may cause biological complications such as tissue inflammation around the implants , gingival growth , and fistula formation .
in particular , joint loosening in an implant treatment restored with the concept of immediate loading may cause harmful stress to the alveolar bone prior to the osseointegration , leading to the failure of the osseointegration.3 the fixture - abutment connection type for the implant system , which is widely used in clinical practice at present , is mainly classified into the external butt joint and the internal cone . in the external butt joint connection type , stress is mainly applied to the abutment screw when a bending force is applied to the superstructure . in the internal cone connection type , the load is mainly transferred via the internal slope of the fixture . such difference in the load transfer mechanism
has been known to affect the stability of the implant connection part.4,5,6,7,8 in general , unlike the external butt joint that requires a second surgery after fixture installation , the internal cone has one - stage products that expose the collar , which is the membrane - penetrating region of the fixture , as well as two - stage products .
the advantages of the two - stage implant are that it predicts a more esthetic outcome in the anterior region , protects the fixture from external force during the osseointegration , and manufactures a temporary denture in the case of poor bone quality.9 on the other hand , the advantages of the one - stage implant are that it does not require a second surgery , there is no microgap between the fixture and the abutment in the subgingival region , and the fulcrum length from the joint connection to the load point is short.10,11,12,13,14 the implant diameter should be selected by considering the teeth defect pattern , depth and width of the residual alveolar bone , rehabilitation space , emergence profile , and occlusion .
implants with wide diameters are mainly used in cases of insufficient edentulous bone height , failure of osseointegration , or required reinstallation due to fixture fracture . due to the advantages of wide - diameter implants
, however , such as the emergence profile improvement , increased contact area between the fixture and the alveolar bone , increased fracture resistance , and wide stress distribution , it is clinically preferred in the posterior region , which has a wide bone width.15,16,17 on the other hand , the platform - switching concept is a method that uses a regular abutment in a fixture with a wide diameter .
the conduct of platform - switching on implants with external butt joint connections has been known to minimize marginal bone absorption resulting in gingival recession and interdental papilla loss , which commonly occur after abutment fastening by placing the fixture - abutment connection part that is a route of bacterial invasion , more internally via the use of a fixture larger than the abutment.18,19,20,21 the aforementioned implant systems that are currently used in clinical practice have various connection types and various diameters of their fixtures , abutments , and abutment screws .
unfortunately , studies on the effect of such factors on the stability of the connection part associated with screw loosening have rarely been conducted .
accordingly , this study was conducted to investigate the effect of the implant - abutment connection design and diameter on the screw joint stability in implant systems with a two - stage external butt joint and one- and two - stage internal cones by comparing the removal torque loss of the abutment screw after repeated loads .
in this study , the usii system with an external butt joint , the ssii system with a one - stage 8 internal cone , and the gsii system with a two - stage 11 internal cone from osstem implant ( osstem , pusan , korea ) were used ( fig .
a fixture with two types of diameter was used in each system . a cement - retained abutment and wc / cta ( coated with tungsten carbide / carbon ) screws were used ( table 1 and table 2 ) .
a fixture with a 1.8 mm - high collar was used in the one - stage implant ssii system , and an abutment with a 2.0 mm - high collar was used in the other systems to maintain the same height at the load point .
the subjects were divided into a total of seven groups according to the abutment - fixture connection type and diameter , including platform - switching type samples that used a regular abutment in their fixture with a wide diameter in the usii system .
the implant fixture was fixed to the separately manufactured jig , and the abutment was fastened to the implant .
then a 30 ncm tightening torque was applied to each abutment screw using a digital torque gauge ( mgt12e , mark-10 co. , hicksville , ny , usa ) for standardization according to the manual of each manufacturer .
ten minutes later , the same tightening torque was applied again to compensate for the preload loss due to the surface sinking .
then the removal torque of each abutment screw was measured using a digital torque gauge . to minimize the change in the removal torque due to the repeated fastening , a total of 35 fixtures , abutments , and abutment screws were used in each system ( five per experiment group ) .
the implant fixture was fixed to jig in a repeated load device ( instron 8841 , instron co. , england ) , and the abutment was fastened with an abutment screw by applying a 30 ncm tightening torque , as in the measurement of the initial removal torque .
then , a machined stainless steel metal tube with disc shape was attached to abutment using a resin - class temporary cement ( premier implant cement , premier dental products co. , la vista , ne , usa ) ( fig .
a minimum 10 n , and a 10 hz cycle was applied to the metal tube , 5 mm away from the center axis of the implant .
then , 10 cycles and a 30 ncm tightening torque were applied again for the simulation of more actual clinical situations . with the same method ,
10 cycles of repeated load were applied , and the removal torque was measured using a digital torque gauge .
postload removal torque loss ( % ) = [ ( initial removal torque value - postload removal torque value ) / initial removal torque value ] 100 statistical analysis was performed using spss ver .
18.0 ( spss , chicago , il , usa ) . to analyze measurements taken at each group were compared using kruskal - wallis test .
when the kruskal - wallis test was statistically significant , multiple comparison analysis was performed as a post - hoc test , using the mann - whitney u test .
the mean and standard deviation of the removal torque before and after the load in each implant system was presented in table 3 .
the initial removal torque was higher in group ii than in group vii ( p<.05 ) , and no significant difference was found among the other groups ( p>.05 ) .
the postload removal torque was highest to lowest in the regular - diameter comparison ( p<.05 ) in the following groups , in this order : vi , iv , and i ; and in the wide - diameter comparison ( p<.05 ) in this order : vii , v , and ii .
no significant difference was found between group iii and group ii in the usii system ( p>.05 ) .
the different lowercase superscript letters in the initial and uppercase superscript letters in the postload are significantly different ( p<.05 ) . the mean and standard deviation of the removal torque loss in each system before and after the load are presented in table 4 . for the regular diameter ,
the postload removal torque loss was higher in group vi than in groups i and iv ( p<.05 ) , but no significant difference was found between group i and group iv ( p>.05 ) . for the wide diameter , the removal torque loss was higher in groups v and vii than in group ii ( p<.05 ) , but no significant difference was found between group v and group vii ( p>.05 ) . in the comparison of the implant diameters ,
the postload removal torque loss was higher in group vi than in group vii ( p<.05 ) , but no significant difference in the removal torque loss was found among the other groups ( p>.05 ) .
in addition , there was no significant difference between group iii and group ii in the usii system ( p>.05 ) .
the different lowercase superscript letters in the torque loss denote significant differences ( p<.05 ) .
screw loosening is caused by an inappropriate tightening torque , the surface sinking phenomenon , screw deformation and preload loss due to overload , and vibration due to the functional load.22 the preload , which is a compressed force that occurs between the abutment and the fixture due to the tightening torque , increases as the tightening torque increases and the friction coefficient of the screw decreases.23 if the tightening torque is applied to the abutment screw , or if the external load is applied to the implant superstructure , the surface roughness wear is smoothened due to the compressed force .
this settling effect reduces the preload , which leads to screw loosening.24 to compensate for the preload loss caused by surface sinking in actual clinical practice , the tightening torque must be applied again 10 minutes after a new screw is fastened , and the tightening torque must be regularly and repeatedly applied after the functioning of the implant prosthesis.25 in this study , based on previous reports , the tightening torque was repeatedly applied 10 minutes after the screw was fastened , and after 10,000 cycles of repeated loads to compensate for the surface sinking caused by the functional load . for the external butt joint connection type , the stress caused by all the external loads , except for the tightening torque and the load of the implant major axis ,
is applied to the screw.8 the external hexagon of the external butt joint was developed to provide the abutment direction upon the fixture installation and the superstructure manufacturing , and it was difficult to achieve resistance against the lateral force .
in addition , the fulcrum length for the lateral force was longer compared to the internal cone connection type , and most external hexagons have a gap in the hexagon between the abutment and the fixture , and mainly depend on the friction caused by the preload for the torsion stress .
therefore , it is very important to apply the appropriate preload to stabilize the connection parts in the external butt joint.26,27,28,29 on the other hand , in the internal - cone - connection - type implant system , the tightening torque is driven by not only the screw height but also the wedge effect due to the conical abutment sinking , and the load is mainly supported by the internal slope of the fixture . therefore ,
the stress that occurs in the abutment screws has been known to be relatively smaller than that in the external butt joint.8 in the internal cone implant system , however , the tensile force of the abutment screw , that is , the preload , was reported to have been slightly reduced due to the slight sinking of the abutment caused by the vertical component of the load . in the external butt joint implant system ,
the preload loss was reported to have been relatively smaller due to the vertical support of the upper fixture.8 despite the same internal cone connection type , in the ssii system that was used in this study , unlike in the gsii system , as the upper shoulder of the fixture collar came in contact with the superstructure , and thus acquired additional support against the vertical load , the abutment sinking became relatively restricted . in this study , however , the load support effect of the aforementioned shoulder was not achieved due to the different study method .
therefore , this restriction should be considered when the results of this study are interpreted .
the preload , which is a contributing factor to the stability of the screw connection parts , is affected by various factors associated with the elongation of the abutment screw .
the measurement of the removal torque of the abutment screw is one of the methods for indirect comparison of preloads . by measuring the initial removal torque ,
the reductions in the degree of the preload caused by the tightening torque can be compared .
the factors that affect the initial removal torque include friction , surface sinking , and abutment sinking . by measuring the removal torque and calculating the loss rate after the repeated loads that are clinically more important , the reduced preloads due to the external load ,
that is , the joint stability against the functional load , can be indirectly compared .
the joint stability against the functional load is affected by the surface sinking of the implant system , the joint micro - movement , the abutment screw deformation , and the abutment sinking . in this study ,
the initial removal torque was higher in the usii system than in the gsii and ssii systems for both the regular and wide diameters .
this is because more preload might have been occurred in the usii system with the external butt joint connection type , which may have led to increased friction .
the compressed force was higher in the external butt joint , wherein the tightening torque was mainly converted into the compressed force via the screw elongation , than in the internal cone when the same torque was applied.30 on the other hand , unlike previous study results in which the joint stability was superior in the internal cone than in the external butt joint,31,32 the postload removal torque loss was lowest in the usii system for both the regular and wide diameters , and increased in the order of the ssii system and the gsii system , although the difference was not statistically significant .
the aforementioned difference in the results is likely to be attributable to the experimental devices or load point and differences in the load condition such as the repeated load number .
the high removal torque loss in the internal cone connection type was mainly attributable to the preload loss caused by the abutment sinking .
the removal torque loss was lower in the ssii system than in the gsii system , although both systems were of the internal cone connection type .
the aforementioned result is likely to be attributable to the one - stage implant with a 1.8 mm collar reduced fulcrum length .
theoretically , if the implant system diameter increases , the preload loss caused by the bending load during the functional movement relatively decreases due to the increased area between the abutment and the fixture .
it was reported that the joint opening due to the fulcrum load was lower in the wide - diameter implant system than in the regular - diameter implant system in a repeated load experiment in which a strain gauge was used.33 when the fulcrum load at the upper fixture was applied to a 10 mm - tall metal tube , the external force that was applied to the abutment screw was calculated in the moment form using the following formula.34
fs = [ ( fh 10 ) - ( fv lv ) ] / ( 0.5 d ) wherein fs is the external force applied to the abutment screw , fh is the horizontal component of the load , fv is the vertical component of the load , lv is the distance from the vertical component of the load to the fulcrum point , and d is the fixture diameter .
theoretically , the external force applied to the abutment screw decreases as the fixture diameter increases . in the comparison of the implant diameters in this study , no significant difference in the postload removal torque loss was found between the usii and ssii systems .
the reason for the lack of reduction of the loss in the usii and ssii systems despite the increased diameter is unclear . in this study ,
a 30 ncm tightening torque was applied in the usii system with a wide diameter , as in the other test groups , despite its larger abutment screw diameter .
if the abutment screw diameter increases , relatively less screw elongation could occur when the same tightening torque is applied .
therefore , it is likely that the preload loss due to the surface sinking caused by the tightening torque and the repeated load could occur more in the wide - diameter implant system with less screw elongation , and result in the partial removal of the moment reduction effect caused by the increased diameter .
the relatively increased lateral wall thickness is likely to be attributable to the reduction in the removal torque loss in the wide - diameter gsii system .
platform - switching has been reported to reduce marginal bone resorption by concentrating the stress more internally during the dynamic function,17 in addition to the biological effects that are achieved by placing the fixture - abutment connection more internally.35 the results of this study showed , however , no significant differences in the removal torque and the loss rate after repeated loads between group iii , which corresponded to the platform - switching usii system , and group ii , which corresponded to the wide - diameter usii system .
the aforementioned result indicates that no significant difference in the external force applied to the abutment screw was found , as platform - switching uses an abutment with the same diameter shown in a finite element analysis,36 in which no significant differences in the stress distribution and the joint opening were found according to the platform - switching . in this study ,
the screw joint stability was indirectly compared via the removal torque loss after repeated loads . unlike in the external butt joint wherein the joint stability is wholly maintained by the preload caused by the tensile force of the abutment screw , the internal cone connection type achieved additional joint stability from the wedge effect caused by the abutment sinking and the screw preload .
therefore , it is more appropriate to interpret the results of this study by restricting them to the screw loosening of the abutment rather than to directly associating them with the clinical failure of the fixture - abutment connection .
in addition , a further comparative study on the wedge effect of the internal - cone - connection - type on the joint stability is required .
in this study , the results of this study showed that the external butt joint was more advantageous than the internal cone in terms of the postload removal torque loss .
for the difference in the implant diameter , a wide diameter was more advantageous in terms of the torque loss rate .
the results of this study showed that the implant - abutment connection design and diameter affect the screw joint stability .
as preload loss due to the functional load could occur in any implant system , regular examination and the re - torque process for an appropriate tightening torque are required . | ### Summary:
: purposethis study was conducted to evaluate the influence of the implant - abutment connection design and diameter on the screw joint stability.materials and methodsregular and wide - diameter implant systems with three different joint connection designs : an external butt joint , a one - stage internal cone , and a two - stage internal cone were divided into seven groups ( n=5 , in each group ) .
the initial removal torque values of the abutment screw were measured with a digital torque gauge .
the postload removal torque values were measured after 100,000 cycles of a 150 n and a 10 hz cyclic load had been applied .
subsequently , the rates of the initial and postload removal torque losses were calculated to evaluate the effect of the joint connection design and diameter on the screw joint stability .
each group was compared using kruskal - wallis test and mann - whitney u test as post - hoc test ( =0.05).resultsthe postload removal torque value was high in the following order with regard to magnitude : two - stage internal cone , one - stage internal cone , and external butt joint systems . in the regular - diameter group ,
the external butt joint and one - stage internal cone systems showed lower postload removal torque loss rates than the two - stage internal cone system . in the wide - diameter group ,
the external butt joint system showed a lower loss rate than the one - stage internal cone and two - stage internal cone systems .
in the two - stage internal cone system , the wide - diameter group showed a significantly lower loss rate than the regular - diameter group ( p<.05).conclusionthe results of this study showed that the external butt joint was more advantageous than the internal cone in terms of the postload removal torque loss .
for the difference in the implant diameter , a wide diameter was more advantageous in terms of the torque loss rate . |
<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 net effect of alcohol consumption on health is detrimental , with an estimated 3.8% of all global deaths and 4.6% of global disability - adjusted life - years attributable to alcohol ( 1 ) .
alcohol consumption is linked to long - term health and social consequences through three intermediate mechanisms : intoxication , dependence and direct biological and toxic effects ( 2 ) .
in addition to the volume and patterns of drinking , alcohol quality may also have an impact on health issues ( 2 , 3 ) .
in most regions of the world , the legal availability of alcohol is generally accepted to be one of the primary controls on levels of alcohol consumption and expected harms .
licensing systems are , therefore , a key component of an overall alcohol control policy . in iran , alcohol consumption is forbidden due to legal and religious grounds , and alcoholism is not considered a major public health concern . despite this prohibition , alcoholic beverages are made and sold illegally in iran . hence , noncommercial and unrecorded alcohol remains a considerable concern that needs intelligent and realistic policy options .
generally , the consumption of noncommercial alcohol ( i.e. , homemade alcoholic beverages ) among individuals in the lower classes of the population is higher than individuals in the upper classes , who normally are able to have access to commercial alcohol .
there have been persistent claims that consumption of unrecorded alcohol causes harm due to toxic ingredients other than ethanol ( 3 ) .
. roughly , less than 0.1% of the global alcohol - attributed deaths are due to methanol ( corresponds to 2,740 deaths based on the global burden of disease ) ( 3 , 4 ) .
other than methanol , there are other potential toxic effects of noncommercial alcohol samples due to ingredients other than ethanol .
recently , concerns have been raised about the higher levels of alcohols in noncommercial alcohol ( 5 ) .
there is also a continuing discussion on the presence of lead in noncommercial alcohol ( 6 ) .
in addition to methanol and lead poisonings , ethylene glycol , polyhexamethylene guanidine ( phmg ) and acetaldehyde have occasionally been a concern ( 7 , 8) .
several cases of methanol poisoning due to noncommercial alcohol consumption were recorded during the last decade .
however , there is no literature on the composition of noncommercial beverages in iran . the forensic toxicology laboratory in the mashhad legal medicine organization , as a major laboratory center in the east of iran , provides routine analytical toxicology testing , and a large number of samples
this paper presents results of chemical composition and potential harm analysis in obtained unrecorded alcohol samples from the context of the city of mashhad in iran .
the purpose of our study was to identify potentially toxic components in noncommercial alcoholic beverages in the context of the city of mashhad in ir iran .
all samples ( n = 887 ) were collected during law enforcement by the police in mashhad and the suburbs between march 2013 and march 2014 and submitted to a legal medicine organization .
methanol and ethanol levels in the alcoholic beverages were determined through direct injection gas chromatography with a flame - ionization detector ( gc - fid ) method . regarding the legal medicine organization rules ,
alcoholic samples were identified by a number , and the analyst was not aware of the content of the samples .
in total , 887 samples were under study ; more than 50% of samples were obtained from mashhad and the rest were from suburbs .
of the samples , 32.5% were obtained in the spring , followed by 24.8% in the summer , 22.4% in the fall and 20.1% in the winter .
the percentage of ethanol in our study was divided into three groups . as can be seen in table 1 , in just a few of the samples ,
the percentage of ethanol was more than 60% , whereas in a significant proportion ( 59.8% ) of the samples the ethanol percentage was between 31% - 60% , and a noticeable proportion ( 38.5% ) was less than 30% . to sum up , the ethanol percentage in the samples ranged from 0% to 98.4% , with an average percentage of 30.04% . in the total of 877 samples ,
as outlined in table 2 , the results for the ph of the alcoholic samples are divided into five groups .
about 30% of global alcohol consumption comes from unrecorded sources , but there are huge regional differences ( 9 ) . in consideration of the legal prohibition of alcohol production and consumption in iran , illegally produced and smuggled alcohol remains a considerable concern .
noncommercial alcoholic beverages seem to be that which is affordable for alcohol consumers . however , published data on the chemical composition of noncommercial alcoholic beverages is scarce in iran .
the percent of alcohol by volume is now the harmonized measurement for alcohol strength ( 8) . the accurate and rapid determination of ethanol in alcoholic beverages is very important for safety and economic reasons ( 8 , 10 ) .
some studies have shown that the unrecorded alcoholic beverages have higher ethanol levels than those that are commercially available ( 3 ) .
the obvious example is the ethanol percent of illegal alcohol products in russia , which has created public health concerns relating to the consumption of unrecorded alcohol , and are due mainly to the ethanol content ( 11 , 12 ) .
even so , in many studies a majority of unrecorded beverage samples had a uniform alcohol content of around 40% by volume and a tiny minority had more than 60% by volume , which is similar to the commercial alcohols ( 3 , 13 , 14 ) . in the current study ,
volume percentage of ethanol in a noticeable proportion of the samples ( roughly three out of five ) was 31% - 60% and in a negligible proportion ( 1.7% ) was more than 60% . comparing the current study with the others in the context of ethanol percentage ,
regarding the toxicological point of view , it is not a warning for public health , but it is certainly important to identify the practical consequences of these illegal alcohols , such as the short - term consequences ( e.g. , unintentional injuries and deaths , suicide , violent behavior ) and the long - term problems ( e.g. , liver cirrhosis , cardiovascular disease , mental problems and cancers ) .
it is impossible to argue against the fact that the vast majority of alcohol - related deaths are due to ethanol ( 1 , 14 , 15 ) .
data about all the potentially presenting compounds in unrecorded alcohol reveals the substantial acute toxic effects of methanol . the current european union limit for naturally occurring methanol in alcoholic drinks is 0.4% by volume for methanol at 40% by volume for alcohol ( 16 , 17 ) .
it should be noted that the methanol content would need to exceed 2% ( v / v ) for toxic harm ( 16 ) . in the current study ,
methanol was detected in only four cases of the samples , however , all of the four cases exceeded the methanol percent limit for toxicity ( more than 2% ) , and the mean of the methanol percentage was 23% .
there is no doubt that toxic effects are expected in the four cases , although we did not have access to objective evidence about the practical consequences of consumption based on the records ; nevertheless , serious emphasis on prevention is necessary .
it is interesting to note that higher alcohol consumption in these two seasons is mentioned in some other studies as well ( 18 , 19 ) .
on one hand , noncommercial alcoholic beverage production , sale and consumption has no seasonal rhythm ; on the other , it seems that alcohol users in our study are occasional rather than regular users .
however , more study is needed to investigate the many unanswered questions regarding the impact of the seasons and weekdays on the sale and consumption of noncommercial alcoholic beverages .
there is a clear trend in ph of the samples , ph in just over three quarters of the samples was in the range of four to six .
total acidity in alcoholic beverages is initially due to the presence of volatile acids , such as acetic acid or tartaric acid , and dictates the chemical processes taking place in alcoholic beverages ( 10 , 20 ) . in the current research , we have studied the general composition of noncommercial alcohol samples .
a more pervasive approach is required for other compounds ( e.g. , higher alcohols , metals , acetaldehyde , ethyl carbamate , diethyl phthalate ) .
annually , there are many cases admitted to the medical toxicology center of mashhad because of methanol poisoning due to homemade alcohol consumption .
to conclude , the current study presents results from the chemical composition analysis and expected potential harm from noncommercial alcohol in mashhad and its suburbs .
this investigation provides inadequate evidence to infer the influence of noncommercial alcohol composition on alcohol - related clinical toxic effects over the effects of ethanol .
we detected a relatively high percentage of methanol in four samples , and it is important to emphasize that detailed future research should focus on the other potential components in unrecorded alcohol . | ### Summary:
: backgroundiran has one of the lowest alcoholic beverage use rates in comparison with other countries , because it is legally forbidden and because of religious beliefs .
even so , unrecorded and noncommercial alcohol remains a considerable concern , which needs special attention.objectivesin the current research , we have studied the general composition of noncommercial alcohol samples to identify potentially toxic components in the context of the city of mashhad in ir iran.patients and methodsusing a descriptive study , chemical composition records of alcohol samples obtained from mashhad and its suburbs ( from march 2013 to march 2014 ) were evaluated in terms of ethanol percentage and methanol percentage using gas chromatography .
likewise , the ph of the alcohol and the location of the sample were also considered .
some substances , such as inorganic elements , were not included because there was no information about these substances in the records.resultsof 877 reports of alcohol samples , more than 50% were obtained from mashhad and the rest were from the suburbs . of the reports , 57.5% were in the spring and summer , followed by 42.5% in the fall and winter .
the mean ( min - max ) of ethanol percentage was 30.04% ( 0 - 98.4 ) . in four cases
, methanol was detected .
the mean ( min - max ) of methanol percentage was 23% ( 4 - 95).the majority of the samples had an acidic ph.conclusionsthe composition of unrecorded samples did not raise major toxicological concern beyond ethanol in alcohol products .
however , concentration levels of methanol in some unrecorded alcohol samples made these samples detrimental for human consumption . |
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: although acute kidney injury ( aki ) is extremely common - with an incidence of about
2,100 per million population , similar to that of acute myocardial infarction - the condition remains
difficult to treat and prognosis is poor .
indeed , early mortality associated with some
forms of aki is greater than that associated with acute myocardial infarction despite
available supportive therapy such as dialysis or hemofiltration .
aki , or kidney attack , should thus be considered every bit the medical
emergency that we think of heart attack .
for this reason , the kidney disease : improving global outcomes aki guideline begins not
with patients already with aki but with patients at high risk of the disease .
unlike myocardial infarction , kidney attack is usually silent without signs
and symptoms that guide risk assessment .
a number of susceptibilities ( for example ,
advanced age , underlying chronic disease ) and exposures ( for example , sepsis ,
radio - contrast ) for aki have been identified but there is no reliable way for a
clinician to use this information to establish a clear risk profile .
by contrast , a
patient with pre - existing diabetes and hypercholesterolemia who presents with crushing
substernal chest pain is undoubtedly at high risk for myocardial infarction .
the concept
of renal angina has been put forth , but this has been defined on the basis of small changes in renal function in
patients already deemed to be at high risk . by definition , then , moderate - risk patients
can only have renal angina when they manifest changes in renal function , often when
kidney damage has already occurred and when it may be too late to apply treatments to
preserve renal function .
furthermore , recent studies have highlighted the possible
occurrence of subclinical aki where the diagnosis can not be made with classic criteria .
if patients could only tell us that their kidneys hurt then front - line clinicians could
stratify patients who were most likely to develop aki and do this at a time when
interventions ( such as stopping nephrotoxins ) would be most likely to be effective .
furthermore , and
again analogous with myocardial infarction , a tool for risk
stratification would tell us which patients to monitor more closely , not with telemetry
but instead with careful measurement of urine volume and serum creatinine . in a provocative paper by kashani and colleagues ,
the concentration of two novel markers
- insulin - like growth factor - binding protein 7 and tissue inhibitor of
metalloproteinases- 2 - was found to be increased in the urine of patients at high risk
of aki from a variety of etiologies .
the authors then validated these markers in a separate large multicenter
study and compared them with known markers of aki such as neutrophil
gelatinase - associated lipocalin and kidney injury marker-1 .
not only did each marker
perform better than other known markers , but their combination provided additional
information , at least in some patients .
for example , compared with the lowest third , patients
manifesting these new markers at concentrations in the middle third had a threefold
increase in risk while the third with the highest levels had a 10-fold increase .
these
markers therefore appear to be the pain signal that is missing in this silent
disease .
an intriguing implication of this study is that , because both of these new markers can
be upregulated in response to a wide range of noxious stimuli , they have the potential
to be a nonspecific alarm raised by the renal tubules in response to stress .
detecting
this alarm will permit several things to happen , including appropriate triage of
patients , more intensive monitoring , and perhaps early involvement from specialists in
nephrology and critical care who can promptly evaluate these patients while they are
still in the golden hours of this disease prior to irreversible damage to the
kidneys . finally ,
as new therapies for aki are being evaluated in the next few years , the use of
biomarkers to help select which patients should be enrolled in trials will be an
enormous advantage over current study designs . in conclusion ,
every single insult to the kidney is potentially dangerous and
deleterious for the clinical outcome and future progression of chronic kidney disease .
because early diagnosis and thus related interventions appear possible today thanks to
the use of new biomarkers , we should echo the world kidney day 2013 claim to ' stop
kidney attack ' .
| ### Summary:
: kashani and colleagues studied two novel markers , insulin - like growth factor - binding
protein 7 and tissue inhibitor of metalloproteinases-2 , in the urine of patients at
high risk of acute kidney injury ( aki ) .
they validated these markers in a separate
large multicenter study and compared them with known markers of aki such as
neutrophil gelatinase - associated lipocalin and kidney injury molecule-1 .
insulin - like
growth factor - binding protein 7 and tissue inhibitor of metalloproteinases-2
performed better than other known markers and their combination provided additional
information .
these markers could be useful in clinical practice to uncover silent
episodes of aki or to make an early identification of patients at risk .
ultimately
they could help to detect and possibly prevent episodes of acute injury to the
kidney , sometimes referred to as kidney attack . |
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: we report the outcome of 2 patients of neglected hip dislocation which were treated by open reduction and internal fixation by k - wires .
we treat 2 children both girls ( one was of 4 years and other was 7 years of age ) . in both cases dislocation
patients were allowed to bear weight from gradual to full weight bearing after 6 weeks .
traumatic hip dislocation in children differs from those from adults as it is less common , requires less trauma to produce dislocation , has less associated injuries has less complication rates like traumatic arthritis , myositis except avascular necrosis , in young children between 2 to 5 years of age where acetabulum is soft with pliable cartilage generalized joint laxity , minimal trauma can produce dislocation .
posterior dislocation is diagnosed on the basis of classical deformity of flexion , adduction and internal rotation .
common cause for missed diagnosis is associated shaft fracture due to which classical features of dislocation were masked . in literature definition of old or late dislocation of hip is not clear . according to garret et al ( 1979 ) that patients who were not treated within 72 hours after injury were called as old unreduced dislocation of hip .
the option for management of hip dislocation in children are closed and open reduction , subtrochantric osteotomy , or leave as such and wait for adulthood for total hip replacement .
the aim of our case report was to evaluate the outcomes of reduction in the treatment of traumatic posterior hip dislocation in children .
we treat 2 children both girls one was of 4 years and other was 7 years old . in both children there was unilateral posterior dislocation and was not associated with any fracture [ fig .
first case was due to road traffic accident while second was due to fall from height .
both cases were initially treated by bone setters and history of massage and manipulation was present in both cases . first came to hospital 10 weeks after trauma while second case came after 18 weeks after .
pre - operative x - ray pelvis with both hips ap .. showing dislocation of left hip .
both children were treated by upper tibial skeletal traction ( 2 to 3 kg ) and counter traction .
the traction was applied for about 3 to 4 weeks with involved extremity in abduction . in both cases dislocation
after that both cases were operated by open reduction by postero lateral approach . in both cases acetabulum was filled with fibrous tissue .
the hip was held in position with the help of k wire through the femoral head into acetabulum [ fig . 2 ] .
the k wire was removed at 3 to 4 weeks and hip mobilizing and quadriceps and knee bending exercises were allowed .
patients were allowed to bear weight from gradual to full weight bearing after 6 weeks .
post - operative x - ray pelvis with both hips ap after reduction of hip showing k wire .
the results were graded as excellent , good , fair or poor according to garret et al criteria .
an excellent result meant no pain , a full range of hip motion and no limp .
fair result meant pain but not disabling , moderate limp , 50 % range of movement .
poor result meant disabling pain , marked limitation of hip motion and abduction or adduction deformity.[fig .
radio logically in both cases there was various degree of osteonecrosis of femoral head and neck with preservation of the joint space .
we have seen2cases of neglected dislocation of the hip in children within 2years in this hospital .
stevart and milliford reported that this injury is twenty five times less common in children as compared to adults .
in developed countries neglected and unreduced dislocation is rare as compare to developing countries because of low social economic status . in developing
countries patients came to hospital many days after trauma with repeated massage and manipulations . in developing countries unlike adults relatively slight trauma and a trivial fall account for dislocation in children .
after injury treatment of neglected dislocation of hip becomes difficult with time . with time acetabulum becomes filled with fibrous tissue in unreduced dislocation so reduction becomes impossible by closed means .
besides open reduction of neglected dislocation subtrochanteric osteotomy and symptomatic treatment until skeletal maturity when reconstruction can be done .
closed reduction and manipulation under general anesthesia could be done if dislocation is of short duration ( 2 - 4 weeks ) .
closed reduction and heavy traction with involved extremity in abduction give good results in selected cases . in this method limb
is placed in heavy skeletal traction ( 15 - 20% of the patient s body weight ) for 3 to 5 days in line of deformity .
when the head is at the level of acetabulum the limb is gradually abducted to achieve reduction .
once the hip becomes concentric , weight of traction is reduced and maintained for 3 weeks . various study on
this study showed that this method was done in 40 cases of dislocation in children .
banskota ak et al in their study on 8 cases of neglected posterior dislocation on hip give good results in 3 , fair in 3 , and poor in 2 according to garrett et al criteria .
leg lengths were within 2 cm in 7 of 8 cases , and only 1 patient had a discrepancy greater than 2 cm .
zrig m et al in their study on 7 children on traumatic posterior dislocation treated the dislocation by closed reduction .
role of skeletal traction initially before open reduction is useful because it stretches the contracted soft tissue .
verma in his study on 14 cases of neglected dislocation of 14 days to one year duration did open reduction and reported excellent results in 4 cases , good outcome in 4 cases , fair outcome in 1 case while poor outcome in 5 cases .
kumar and jain in their study on 18 patients of neglected posterior dislocation treated them by open reduction because by skeletal traction dislocation could not be reduced . in their study
traumatic dislocation of hip should be reduced as early as possible . because delay in reduction increases the chances of avascular necrosis , posttraumatic osteoarthritis and end result depend on the age of patient , type of dislocation and severity of trauma .
mehlman in his study reported that if hip dislocated for a length of time osteonecrosis can be significantly associated .
if reduction was delayed for more than 6 hours , there will 20 times higher risk of osteonecrosis .
damage to growth plate leads to leads to shortening of femoral neck , coxa vara , coxa valga or widening of femoral neck .
it prevents not only deformity but also maintains limb length . in developing countries like india poverty , ignorance and malpractice by quacks
though rare , neglected dislocation of hip is a serious condition and should be treated as early as possible to prevent avascular necrosis of head of femur . | ### Summary:
: introduction : traumatic dislocation of the hip in children is a rare injury . we report the outcome of 2 patients of neglected hip dislocation which were treated by open reduction and internal fixation by k-wires.case report : we treat 2 children both girls ( one was of 4 years and other was 7 years of age ) . in both cases dislocation was unilateral and was not associated with any facture .
both cases were of posterior dislocation . in both cases
open reduction and internal fixation was done by k wires .
hip spica was applied post operatively in both cases .
the k wire was removed at 3 to 4 weeks .
patients were allowed to bear weight from gradual to full weight bearing after 6 weeks.conclusion:we conclude that open reduction is a satisfactory treatment for neglected hip dislocation .
it prevents not only deformity but also maintains limb length . |
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: the detection of specific macromolecules ( e.g. , protein antigens ) remains an important concern in the fields of human and animal health diagnostics , food safety testing , and basic research .
one of the most widely used approaches for this purpose is the enzyme immunoassay ( eia ) technique . the classic sandwich eia utilizes specific antibodies immobilized on a solid phase to create a high - affinity surface for the capture of antigens , which are subsequently detected by reaction with an enzyme - linked antibody .
the use of antibodies as assay reagents suffers from the high cost and time required for their production , as well as variability in stability , quality , and yield which may occur from one batch to another . coating the solid phase with capture antibody consumes a high quantity of the available antibody , which must be applied in large excess to drive its immobilization on the solid phase .
a variety of solid phases such as nonporous polystyrene microwells and microporous membranes lend themselves to the immobilization of antibodies for eia procedures .
macroporous polyester cloth has also been used as a solid phase for the immobilization of antibodies in the development of simple dot blot assays .
compared to nonporous and microporous solid phases , polyester cloth has the advantages of offering a readily available large surface for the immobilization of immunoreagents promoting rapid immunoreaction kinetics and ease of washing between reaction steps .
aptamers made of dna or rna oligonucleotides have emerged as a new class of synthetic receptors which in some applications may replace antibodies as reagents for the assay of macromolecule analytes , such as proteins associated with pathogenic bacteria .
aptamers recognizing a wide array of different proteins have been produced , and there have been several reports of their adaptation as detection reagents in biosensors and other assay devices in which they are immobilized on a solid surface to serve in signal transduction upon binding with an analyte .
many of these assay systems utilize specialized custom - built devices or complex chemistries for aptamer immobilization and reagent detection . here , we examine the of use of polyester cloth as an adsorbent for dna aptamers in the development of simple assays utilizing cloth strips upon which multiple samples can be blotted and hence processed simultaneously .
the immobilization of oligo - dna probes on polyester cloth by brief exposure to ultraviolet light for use in the detection of polymerase chain reaction ( pcr ) products by hybridization has previously been shown , and it is surmised presently that this simple approach should also permit the immobilization of dna aptamers to create a high affinity capture surface for the assay of target analytes . in this
target molecules captured on the aptamer - coated cloth surface are detected by reaction with a dilute preparation of specific antibodies linked to a marker enzyme .
the detection of thrombin is presently considered as a model system , since dna aptamers for this protein have been well characterized [ 5 , 6 ] and specific antithrombin antibodies are commercially available .
aptamers used in the present study were selected against the human coagulation protein thrombin ( table 1 ) .
aptamer 3 was designed for a different study by modifying aptamer 2 to incorporate additional randomly generated sequences appended at the 5 and 3 ends for primer annealing for polymerase chain reaction applications ( not covered in the present work ) .
it was included in this study because it represents a version of thrombin - binding aptamer of intermediate size .
the human -thrombin used in these studies was from a commercial source ( haematological technologies inc , hct-0020 , essex junction , vt ) and was provided as a 8.9 mg / ml stock with a specific activity of 4493 u / mg and an extinction coefficient ( etcm , 280 nm = 18.3 ) .
sample matrices included pasteurized 1% milk and beef bouillon ( ingredients : beef broth ( water , beef stock ) , yeast extract , salt , flavour , salted onion juice , caramel , disodium inosinate , and disodium guanylate ) , purchased from a local grocer , and the microbial growth medium brain heart infusion ( bhi ) broth ( ingredients per litre : 12.5 g brain infusion solids , 5.0 g beef heart infusion solids , 10.0 g proteose peptone , 2.0 g glucose , 5.0 g sodium chloride , and 2.5 g disodium phosphate ) ( oxoid cm1135 , ottawa , on ) .
polyester cloth ( dupont sontara 8100 ; dupont , mississauga , on ) cut into 2 5 cm strips and bearing a printed sample location grid with 5 cells was manufactured by contract with dave 's custom promotions , inc .
( ottawa , ontario , canada ) , and washed with 95% ( v / v ) ethanol followed by rinsing with deionized distilled water on a filter with vacuum suction .
dna aptamers ( table 1 ) were prepared in high salt buffer ( hsb : 0.1 m tris - hcl ( ph 8.0 ) , 0.01 m mgcl2 , and 0.15 m nacl ) containing 30% ( v / v ) ethanol .
aptamer solution was applied in discrete spots ( 5 l ) on the polyester cloth strips , followed by incubation for 3 hours at 37c in a dry incubator .
the aptamers were cross - linked to the dried strips by exposing the strips to uv light using a uv cross - linker set at 254 nm , 120 mj cm ( stratalinker model 1800 ; stratagene , la jolla , ca ) , and then washed five times with 0.01 m phosphate - buffered saline ( ph 7.4 ) , 0.85% ( w / v ) nacl ( pbs ) containing 0.05% tween 20 ( pbst ) on a filter under vacuum suction .
the strips were blocked by incubation for 1 hour at 37c with 0.5% ( w / v ) bio - rad protein blocking reagent ( bio - rad 170 - 6404 , hercules , ca ) in pbst , followed by washing with pbst .
polyester cloth strips were saturated with 1 ml of aptamer solution and incubated for 3 hours at 37c in a dry incubator .
the aptamer was cross - linked to the dried strips by uv exposure as described above , then washed with pbst , and blocked .
cloth strips coated by spotting aptamer in discrete areas were reacted with thrombin by saturating with 1 ml of pbs containing 13.5 nm of human -thrombin and incubating for 20 min .
strips coated by saturation of the entire surface with aptamer were reacted with thrombin samples by discretely spotting 5 l of human -thrombin at various concentrations in different sample matrices ( pbs , 1% milk , bhi broth , and beef bouillon ) and then incubated for 20 min .
bound thrombin was assayed by sequential 20 min reactions of the strips with 1 ml containing antihuman thrombin antibody ( haematological technologies inc , aht-5020 , essex junction , vt ) diluted 1 : 1000 in pbst , and 1 ml of antimouse igg - peroxidase conjugate ( sigma - aldrich , a3673 , oakville , on ) diluted 1 : 1000 in pbst , with pbst washes after each step .
finally , the strips were saturated with 1 ml of tmb membrane peroxidase substrate ( kirkegaard & perry laboratory , 50 - 77 - 02 , gaithersburg , md ) and incubated for 10 minutes .
reactions were graded qualitatively as follows : positive ( blue spot ) , negative ( no spot ) .
initial experiments examined the immobilization and subsequent thrombin - capturing abilities of different aptamer sequences reported in the literature . for this purpose ,
oligonucleotides representing a range of sizes ( 15 to 105 nucleotides ) and base sequences were immobilized in discrete spots on a strip of polyester cloth and then assessed for binding activity by flooding the entire strip with thrombin solution , followed by detecting bound thrombin by sequential reactions of the strip with antithrombin monoclonal antibody , antimouse igg - peroxidase conjugate , and tmb substrate .
in addition to the thrombin - binding sequences , a 50-mer oligonucleotide probe originally conceived for hybridization with a verotoxin ( vt 1 ) pcr amplicon was also immobilized on the cloth strip to serve as a control for thrombin binding .
a concentration of 10 m for each oligonucleotide , previously shown to be satisfactory for the immobilization of capture probes in pcr applications , was used in these experiments .
shorter aptamer sequences of 15 and 29 nucleotides in length did not produce any visible reaction with thrombin , whereas the longer 67- and 105-mer aptamers cross - linked to the polyester cloth by ultraviolet light exhibited significant thrombin - binding activity manifested as localized immunoenzymatic reactivity on the strip where these probes had been spotted ( figure 1 ) .
no reactivity was observed with the verotoxin probe spot , confirming that the reactions observed with the aptamers were due to their specific thrombin - binding activities and neither was thrombin - binding activity for any of the aptamers in the absence of ultraviolet exposure , suggesting that cross - linking the oligonucleotides to the polyester surface is essential for stable immobilization of the aptamers .
the lack of reactivity of the shorter aptamers may be due to an inability of small dna molecules to bind to the polyester surface , or to a perturbation in their thrombin - binding conformation caused by the cross - linking reaction .
the longer oligonucleotides contained selex primer - binding sequences at their 5 and 3 which are not involved in aptamer function per se , and thus , these appended sequences may serve to provide an immobilization link with the polyester surface sparing the conformational integrity of the aptamer portion .
notwithstanding the foregoing , we investigated the possibility of enhancing the immobilization of shorter aptamers ( e.g. , the 29-mer aptamer ) by synthesizing modified versions of apt 2 bearing different short ( n = 5 ) 5-poly - nucleotide tails ( i.e. , poly - a , poly - c , poly - g , or poly - t ) and immobilizing these on strips of polyester cloth by uv cross - linking as before . the ability of the immobilized aptamer to capture thrombin was determined by reacting the strips with thrombin solution , followed by immunoenzymatic assay of the bound thrombin .
the addition of a poly - g tail produced a weak assay signal , but a more striking result was obtained with a poly - t tail , which produced a signal intensity equivalent to that observed with apt 4 ( figure 2 ) .
these results suggest that poly - t tailing was particularly effective in enhancing the immobilization of the short aptamer in the correct form for analyte capture .
the mechanism for enhanced immobilization of the short aptamer by poly - t - tailing may involve the activation of thymine reactivity by uv irradiation , which is known to occur when genomic dna is damaged by uv radiation in living cells , or perhaps activation of double bonds or other active groups on the polyester ( polyethylene terephthalate ) surface . whatever mechanism is involved in the immobilization of the dna aptamers , these results clearly indicate that a suitable capture surface can be prepared using either a longer ( e.g. , apt 4 ) or a 5-poly - t - tailed ( e.g. , poly - t - apt 2 ) aptamer sequence .
thus , in instances where operational or functional requirements dictate the use of a shorter oligonucleotide sequence , it is possible to achieve functional immobilization of smaller aptamers by the present poly - t - tailing approach , obviating the need for chemical derivatization or the incorporation of specialized nucleotides .
however , since in the present model system there were no constraints on the length of oligonucleotide which could be used , and since aptamer 4 exhibited strong assay signals ( coloured spots ) , it was used for all subsequent experiments . the optimum concentration for coating the polyester cloth
was determined by spotting different amounts of apt 4 and then assaying using the immunoenzymatic procedure as before . a minimum of 0.25 m aptamer solution spotted on the strip produced a detectable assay signal , though the least concentration giving a strong signal intensity was 1 m ( figure 3 ) , which was , therefore , used in subsequent experiments .
the preceding experiments utilized aptamer applied in localized spots on a strip of polyester cloth .
the aptamer - thrombin interaction occurred in a defined buffer devoid of extraneous materials which might produce interference with the binding reaction .
one foreseeable application of the aptablot system is the detection of a target analyte in different sample types , for example , allergens or pathogenic bacteria in various foods submitted for laboratory analysis .
in such a scenario , it would be essential that the aptamer - target interaction be capable of proceeding in various sample matrix compositions , as might be encountered in food sample suspensions or enrichment broth cultures .
furthermore , the ideal assay format would utilize a cloth strip in which the entire surface is coated with the capturing agent , such that the strip could accommodate multiple test samples .
to demonstrate how such a principle might work , strips of polyester cloth were entirely coated by saturation with apt 4 solution .
these were then used for the capture of thrombin from samples spotted in the cells of the printed grid . to determine the impact of the sample matrix
, thrombin was diluted in different types of liquid samples containing complex mixtures of ingredients .
the minimum quantity of thrombin producing a visible assay signal was 1.35 nm in pbs , 0.27 nm ( with weak spot intensity ) in 1% milk and bhi broth ( a typical enrichment medium used in microbiological analyses of foods ) , and 0.27 nm ( with stronger spot intensity ) in beef bouillon ( figure 4 ) .
the reason for the slight improvement in thrombin detectability in the complex sample matrices is not known .
the possibility that this might be attributable to the presence of elevated levels of salts which may affect the formation of active aptamer structures was verified by repeating the assay of thrombin diluted in pbs containing 10 mm mgcl2 and 10 mm kcl , but the detectability in these buffers remained unchanged from that observed with pbs alone ( not shown ) .
we have demonstrated the applicability of a simple aptablot system using a dna aptamer as an inexpensive synthetic capture agent for the sensitive assay of a protein analyte in complex samples .
a unique feature of the aptablot system is the simple means by which the aptamer was immobilized on the polyester cloth surface using a brief exposure to ultraviolet light .
some flexibility in the choice of aptamer length is afforded by the observation that modification with a 5-poly - t - tail enabled the efficient immobilization of a short sequence .
while the present approach does not obviate the use of an antibody detector reagent , it does foster conservation of precious antibody stocks due to their application in highly diluted form , and it also enables the use of monoclonal detector antibodies in instances where the corresponding epitope on the target molecule is only present in one copy ( which is likely the case in the detection of a monomeric protein such as thrombin ) .
all of the components in the present assay system are readily available from commercial sources at reasonable cost .
furthermore , antibodies to many diagnostically relevant molecules are available from commercial sources , and it may be reasonably expected that the number of aptamer sequences to different analytes published in the scientific literature will grow at a great rate as this new reagent technology continues to evolve , expanding the scope of applications amenable to the aptablot approach .
the de novo development of reagent aptamers to other analytes of interest using established protocols is not beyond the capabilities of most basic biochemistry laboratories , and one can envisage future applications in which even the detector antibody used in the present approach may be replaced with a second aptamer bearing an enzyme or other readily assayable marker . more work is needed to expand the scope of application of the aptablot approach from the present thrombin model system to the assay of diagnostically relevant analytes , such as microbial toxins , protein allergens , and environmental contaminants . | ### Summary:
: a simple dot blot immunoenzymatic assay system was developed using polyester cloth coated with an oligo - dna aptamer to provide a high - affinity macroporous surface for the efficient capture of a model protein analyte ( thrombin ) in complex sample matrices such as foods .
bound thrombin was detected immunoenzymatically using a peroxidase - linked antithrombin antibody and a chromogenic substrate . a unique feature of this approach , which we have termed aptablot , is the facile immobilization of dna aptamers on the polyester surface by cross - linking with a brief exposure to ultraviolet light , and the simple assay format obviating the need for specialized instruments .
the assay principle described herein should be broadly applicable to many situations where analytes must be detected in complex samples , with the main limiting factor being the availability of suitable dna aptamers . |
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: human parvovirus b19 is a ubiquitous infectious agent known to cause erythema infectiosum in children , bone marrow suppression and chronic anemia in susceptible individuals , and fetal hydrops and death in intrauterine infections 2 , 25 .
studies have also linked the virus to numerous idiopathic conditions such as systemic lupus erythematosus ( sle)-like syndromes , rheumatoid - like arthritis , and liver and kidney disease 10 , 27 , 37 , 40 .
the role of b19 in the latter set of pathologies is difficult to discern because the cellular tropism of the virus for erythroid precursor cells 33 excludes viral replication as being the cause of the observed cellular damage in replication nonpermissive tissues .
two major hypotheses have been proposed to explain the potential role of b19 in such phenomena : an immune mediated attack of end - organ antigens due to b19-induced molecular mimicry 22 , 43 , or direct b19-mediated cellular damage in the absence of viral particle replication 43 .
evidence for both mechanisms exists and it is possible that both have a role to play in the diverse clinical picture of b19 disease . the b19 linear , single - stranded dna genome encodes three major viral proteins ; two structural capsid proteins ( vp1 and vp2 ) and three non - structural proteins ( the major 77 kda ns1 and the minor 11 kda and 7.5 kda proteins , the latter two whose functions remain unclear ) 39 , 48 .
the humoral response to b19 infection is initially directed against the major viral capsid protein vp2 .
as the recovery process progresses , however , this response becomes replaced by antibodies against the unique region of vp1 24 .
it has been suggested that immune - mediated tissue injury in b19 infection may be the result of cross - reactivity between igg antibodies against vp epitopes and human antigens 22 , 23 . on the other hand ,
the non - structural protein of b19 ( ns1 ) is a candidate mediator of direct cell injury .
b19 virus targets erythroid cells via the major host cell receptor glycolipid globoside , also known as the blood group p antigen 4 , as well as two coreceptors , 51 and ku80 .
the presence of p antigen , however , is not sufficient for b19 replication 43 .
studies have suggested that intracellular conditions , such as viral dna transcription and rna processing , are involved in establishing cell permissiveness 5 , 14 , 21 .
however , tissues identified as non - permissive for b19 replication have been shown to harbor genomic evidence of b19 infection for extended periods of time 7 , 40 .
although such non - permissive cells display an inability to produce viral structural proteins and replicate the viral genome , curiously these same tissues allow transcription and translation of ns1 18 , 34 , 47 .
the non - structural ns proteins of parvoviruses are central to the viral life cycle , mediating viral genome transcription , replication , and packaging .
these multi - domain proteins have a conserved architecture : the n - terminus encodes for the dna binding and endonuclease domains 30 , 45 ; the central region contains the conserved ntp - binding and helicase motifs that identify the protein as a member of the aaa+ sf3 helicase group 9 , 13 , 25 ; and the unique c - terminus region has been suggested to be involved in host - protein interactions and promoter trans - activation activity 10 , 19 , 31 .
the three major genotypes of b19 have been shown to have most of their nucleotide diversity localized to the c - terminus region of its non - structural protein 16 , 37 . however , until recently no specific amino acid variation has been associated with a single clinical presentation of b19 disease 16 , 20 . in 2007 ,
abe and colleagues 1 performed a sequence analysis of b19 ns1 isolated from the livers of two patient groups ; group a contained patients with idiopathic fulminant hepatitis while group b was made up of patients with biliary atresia .
the study correlated the presence of genotypes 1 and 3 in patients with idiopathic fulminant hepatitis , while only genotype 2 was identified in patients with biliary atresia .
furthermore , conserved ( i181 m , e201d ) amino acid substitutions were identified in patients with biliary atresia that were not observed in the fulminant hepatitis group . since
biliary atresia is a congential condition yet to be linked with an infectious cause 36 , identification of conserved amino acid substitutions in the b19 ns1 isolates of only the group a patients suggests that these residues may be critical to the mechanism of b19-associated fulminant liver failure .
b19 has long been linked with a spectrum of liver disease ranging from self - limited hepatitis to acute fulminant liver failure 18 , 28 , 46 .
the significant association of bone marrow suppression with acute fulminant liver failure in the pediatric population 6 , 15 along with the isolation of b19 dna from liver tissue 12 , which has been shown to be non - permissive for viral replication 3 , but allows transcription and translation of b19 ns1 18 , 34 , has lead us to examine the potential role of b19 ns1 in direct hepatocyte cytotoxicity .
our laboratory previously demonstrated that b19 ns1 caused apoptosis in liver - derived cells 34 , 35 .
the above described study by abe et al . 1 led us to explore the effect of the ns1 i181 m amino acid substitution on b19 ns1-induced cytotoxicity in liver cells .
our work has shown that the i181 m substitution significantly reduces b19 ns1-induced apoptosis in hepg2 cells , suggesting an important role for this residue in the mechanism of b19 ns1-induced liver cytotoxicity .
spodoptera frugiperda - derived sf9 cells were cultured in spinner flasks using biowhittaker insect - xpress cell media ( biowhittaker , walkersville , md ) supplemented with 1% penicillin - streptomycin ( penstrep ) ( gibco , invitrogen , carlsbad , ca ) at 27c .
hepg2 cells were cultured in hepatocyte wash media ( gibco ) supplemented with 10% fetal bovine serum ( fbs ) ( gibco ) , 1% l - glutamine ( gibco ) and 1% penstrep .
cloning and recombinant baculovirus production . a modified pfastbac1 ( invitrogen , carlsbad , ca )
the polyhedrin promoter was removed from the pfastbac1 plasmid by snab1 ( fermentas , glen burnie , md ) and bamh1 ( fermentas ) digestion .
the cytomegalovirus ( cmv ) immediate - early promoter was obtained from pcdna3.1 ( invitrogen ) by nrui ( fermentas ) and bamh1 digestion and used to replace the snab1-bamh1 fragment in pfastbac1 , resulting in pcmvfastbac1 .
the vector was again digested with nhe1 ( fermentas ) and bamh1 in order to insert a fragment encoding the enhanced gfp ( egfp ) protein obtained from pegfp - c1 ( clontech laboratories inc .
, saint - germain - en - laye , france ) using the same restriction enzymes , resulting in pcmvegfpwofastbac1 .
briefly , two overlapping fragments of the desired mutant construct were produced using unique internal oligonucleotides encoding a collection of point mutations and deletions and b19 ns1 generic external primers ( table 1 ) .
the two fragments were then annealed by mutually primed synthesis using the ecor1 ( fermentas ) and xba1 ( fermentas ) encoding b19 ns1 generic external primers ( table 1 ) .
the following mutants were generated : patht , a single amino acid replacement , t183a , and pathi , a single amino acid replacement , i181 m .
the ns1 constructs were ligated into the ecor1-xba1 digested pcmvegfpwofastbac1 vector backbone to produce the desired egfp - ns1 fusion protein and its mutations under the cmv immediate - early promoter .
recombinant baculoviruses were prepared using the bac - to - bac baculovirus expression system ( invitrogen ) .
sterile inactivated fetal bovine serum ( fbs ) ( gibco ) was added to each virus to make a 10% solution after which the stock was filtered through a 0.2 m filter ( millipore , billerica , ma ) and stored at 4c .
hepg2 cells were seeded in culture flasks and grown overnight in supplemented media as described above .
the following day the media was removed , cells washed once with sterile phosphate buffered saline ( pbs ) , and the baculovirus solution added to the culture flask .
a multiplicity of infection ( moi ) equivalent to ~100 - 200 was used for each experiment , resulting in a transduction efficiency of ~25% for each virus at 24 hrs post - transduction .
the treated hepg2 cells were kept on ice and remained immersed in the baculovirus solution for 1 hr to promote viral binding to the cellular membrane , after which the virus suspension was removed , the cells washed once with sterile pbs and then pre - warmed supplemented media added .
hepg2 cells were collected by trypsinization ( 0.5% trypsin edta ( gibco ) in pbs ( gibco ) at indicated times , washed once with fresh media ( 500 l ) and counted to prepare required cell numbers per sample for each experiment .
for transduction efficiency analysis , 5 x 10hepg2 cells were resuspended in 500 l of ice - cold pbs and immediately analyzed by flow cytometry . for annexinv binding analysis 5
x 10cells were washed once with pbs and resuspended in 500 l annexinv binding buffer and 5 l annexinv - pe ( ams biotechnology ltd . , abington , ox , uk ) , incubated for 15 min at room temperature in the dark and immediately analyzed by flow cytometry .
the percentage of cells expressing the egfp marker , as well as the distribution of signal intensity for each construct transduced , were established , in order to ensure that a comparable amount of protein was being expressed in each construct transduction , for the comparison of different ns1 mutant groups .
for examination of apoptosis using the subg1 population in cell cycle analysis , 3 x 10 cells were washed once with ice cold pbs and fixed in 70% ice - cold ethanol ( 900 l ) for 24 - 48 hrs at 4c .
the fixed cells were washed twice with pbs to rehydrate the sample and incubated in propidium iodide 40 g / ml ( molecular probes ( invitrogen ) , carlsbad , ca ) and rnase 40 g / ml ( roche basel , switzerland ) in pbs at 37c for 20 min .
the cells were centrifuged , resuspended in ice - cold pbs and immediately analyzed by flow cytometry .
all samples were analyzed on the facscalibur flow cytometer ( becton - dickson , frankline lakes , nj ) , data collected using cell - quest software ( becton - dickson ) , and statistical analysis completed by flowjo software ( tree star , inc , ashland , or ) .
adherent and loose hepg2 cells were collected by trypsinization ( 0.5% trypsin edta ( gibco ) in pbs ( gibco ) at indicated times and washed once in sterile pbs .
the cells were then resuspended 1:10 in trypan blue solution ( 0.8 mm trypan blue in pbs ) and incubated at room temperature 2 - 5 min .
the results were quantified as number of trypan blue staining cells out of total cells counted . statistical analysis .
substitution i181 m in b19 ns1 interferes with ns1-induced apoptotic cell death . to test the hypothesis that b19-associated liver pathology
is related to the direct toxicity of persistent b19 ns1 in hepatocytes of previously infected individuals , we examined the possible role of specific amino acid variation in the b19 ns1 protein on liver toxicity .
the clinical observation by abe et al . 1 of b19 genotype variability in different liver disease groups , identified two amino acid substitutions in b19 ns1 that differed between the biliary atresia and fulminant liver failure patient groups .
substitution e201d , believed to be in the b cell epitope of b19 ns1 40 , substituted one acidic residue for another , suggesting a conserved mutation that would not significantly change the chemical properties of the protein .
an immunological analysis of b - cell activation would need to be completed in order to understand the potential impact of this substitution on b19 ns1 .
therefore , we focused our analysis on the second substitution , i181 m , observed only in genotype 2-carrying biliary atresia patients .
we created egfp tagged constructs of wild type genotype 1 , i181 m ( pathi ) substitution and t183a ( patht ) substitution of b19 ns1 under the cmv immediate early promoter .
the patht substitution was observed in genotype 3 of b19 but not in genotype 1 , both of which could be found in patients with fulminant liver failure , and was used as a second negative control , along with the wild - type b19 ns1 construct .
these constructs were cloned into the baculovirus expression system , which was used as a gene delivery vehicle .
24 hrs post - transduction of hepg2 cells with baculovirus carrying the above described b19 ns1 constructs , trypan blue dye uptake analysis showed an increased amount of cell death in cells expressing b19 ns1-derived proteins compared to mock infected ( cell ) or egfp expressing cells ( figure 1 ) .
although slightly less death could be seen in the pathi transduced cells at 24 hr post-transduction , the difference between the constructs was not statistically significant .
hepg2 cell cytotoxicity continued to increase as the cells continued to express b19 ns1 . at 48 hrs post - transduction
36% ( figure 1 ) of hepg2 cells expressing wild - type ns1 showed loss of viability .
hepg2 cells transduced with constructs expressing pathi and patht exhibited a similar pattern of cell loss , with continued decline in cell viability until 48 hrs post - transduction . however , unlike wild - type b19 ns1- and patht - transduced cells , approximately 10% fewer pathi mutant transduced hepg2 cells showed trypan blue uptake at 48 hrs post - transduction ( p = 0.0002 ) ( figure 1 ) .
previous studies have identified apoptosis as the underlying mechanism for the cytotoxicity observed in the setting of transient b19 ns1 expression 34 .
we therefore examined whether the reduced cell loss observed in the pathi substitution- carrying hepg2 cells resulted from a reduction in cells undergoing apoptosis .
the pattern of apoptosis observed in hepg2 cells expressing all b19 ns1 constructs showed continually increasing percentage of cells undergoing apoptosis starting at 24 hrs ( figure 2 ) . at 48 hrs post
- transduction the pathi construct expressing cells displayed approximately 18% less apoptotic cell death than the wild - type and patht b19 ns1-expressing cells ( p = 0.023 ) ( figure 2 ) .
the reduced apoptotic cell death in the pathi - expressing cells resembled the reduction observed with the generalized cytotoxicity assay , suggesting that the reduced cell loss is due to a decrease in b19 ns1-induced cell suicide , previously reported to be the mechanism of b19 ns1-induced cytotoxicity 34 , 35 .
further confirmation for the reduction of apoptosis in the pathi transduced population of hepg2 cells was obtained using cell cycle analysis of hepg2 cells expressing the wild - type and mutant b19 constructs .
non - transduced hepg2 cells , hepg2 cells transduced with moi 400 of non - engineered baculovirus , and hepg2 cells transduced with egfp expressing virus to 95% transduction efficiency at 24 hrs post - transduction were used to establish hepg2 cell cycle distribution ( negative controls ) .
g0/g1 , s , g2/m and subg1 ( representing cells undergoing apoptotic cell death ) phases were identified on the linear fluorescence intensity plots for propidium iodide emission ( figure 3a ) .
all three negative control conditions displayed the same pattern of cell cycle progression with approximate distribution of cells at 48 hrs as follows ; 71% g1 , 16% s , 12% g2 and 1% subg1 ( data not shown ) . for clarity
only one representative negative control condition , labeled cell , is presented in figure 3 .
hepg2 cells transduced with baculovirus carrying the ns1 constructs were identified by flow cytometry and subsequent cell cycle analysis performed .
the pattern of cell cycle distribution for ns1 expressing cells differed significantly from that seen for the negative controls ( figure 3a bottom panels ) . at 48 hrs post - transduction 20% of hepg2 cells expressing the ns1
the subg1 accumulation demonstrated the cytotoxic nature of b19 ns1 , which has been previously shown to cause apoptotic cell death in hepg2 cells .
the cell cycle observations for ns1 expressing cells were then compared to cells expressing the patht and pathi mutation constructs . at 24 hrs post - transduction
all mutant ns1 proteins exhibited a similar effect on hepg2 cells as the wild - type ns1 protein with approximately 3% of cells in the subg1 population ( figure 3b ) . at 48 hrs post - transduction
, however , a mean of 24.5 % of hepg2 cells expressing the patht construct were found in the subg1 population ( figure 3b ) .
in contrast to this , only 11.5% of pathi expressing hepg2 cells were identified in the subg1 population ( figure 3b ) , suggesting a significant reduction in apoptotic cell death ( p = 0.0317 ) compared to the patht construct expressing hepg2 cells .
no statistical significance was identified between the wild - type ns1 and patht construct expressing cells , which we believe is due to the large variability in the subg1 content data for the wild - type ns1 transduction .
suggestions of a clinical link between b19 and a variety of liver disorders have been reported in the literature 18 , 29 , 46 .
two hypotheses have been proposed : immune - mediated hepatocyte damage resulting from b19-induced molecular mimicry 23 , 46 , or direct liver toxicity from b19 infection of hepatocytes 34 , 46 .
we have previously shown that b19 can infect liver cells and transcribe and translate its non - structural protein 35 .
expression of ns1 in primary hepatocytes as well as in hepg2 cells was shown to be cytotoxic 34 .
activation of the innate apoptotic cascade was demonstrated to be the route of cell demise in the setting of b19 ns1 over - expression , suggesting direct ns1-induced cellular damage 35 .
the endogenous apoptotic cascade is often activated in cells that can not overcome a set of well defined cellular insults such as an accumulation of dna damage , disruptions in mitochondrial membrane integrity , or interference with the dynamic cytoskeletal network .
studies with b19 and other parvoviruses have suggested that the parvoviral non - structural protein can potentially interfere with cellular cytoskeleton proteins 31 , induce dna damage 32 , and promote mitochondrial apoptotic activation 17 .
this evidence along with our own observations led us to investigate the role of direct b19 injury to hepatocytes in the setting of b19- associated liver disease .
parvoviral non - structural proteins are essential for viral replication and packaging , serving numerous roles in the viral life cycle . the multi - domain architecture of parvoviral non - structural proteins results in high conservation of their sequence identity , especially within the well - characterized catalytic regions , such as the endonuclease and ntp - binding motifs .
the highly integrated functions of complex proteins can often be interrupted by single , well placed , amino acid disruptions , which can potentially change the native folding , catalytic capacity , oligomerization state , or other inter - protein interactions .
the identification by abe and colleagues 1 of an amino acid substitution in the ns1 protein of b19 genotype 2 that could not be observed in ns1 proteins isolated from livers of patients with fulminant liver failure , prompted us to explore whether this amino acid substitution can effect b19 ns1 's cytotoxicity in liver derived cells .
in this study , we have demonstrated that substitution i181 m significantly reduces genotype 1 b19 ns1 's cytotoxicity in hepg2 cells .
furthermore , apoptosis was reduced by the pathi construct of b19 ns1 , suggesting that the disruption is in the mechanism by which b19 ns1 induces apoptosis in liver cells .
due to a lack of structural information about b19 ns1 , the role of residue 181 in ns1 function is unclear .
the residue does not appear to fall into the clearly identifiable conserved motifs , such as the endonuclease metal coordination motif huhuu ( residues 81 - 85 ) , or ntp binding p - loop , gxxxxgk ( residues 328 - 334 ) , seen in all parvoviral non - structural proteins .
however , even though the primary structure is not telling , the contribution of this residue to the overall structure of the enzymatic folds can be proposed .
the change from a hydrophobic residue to a more polar one also suggests a disruption in the potential orientation of the side chain and hence a change in the secondary structure of that region in the protein .
since the i181 m substitution did not obliterate b19 ns1 cytotoxicity , but only reduced it , the protein continues to maintain some function , suggesting that this substitution may also reduce viral fitness .
b19 replication is difficult to study due to the lack of an efficient b19 viral replicon and therefore direct experimental verification of the role of amino acid variation on replication efficiency or viral fitness must await the availability of such tools .
however , based on the results of this study , we can conclude that substitution i181 m reduces b19 ns1 cytotoxicity in liver cells , potentially resulting in reduced hepatocyte dropout and thereby a reduced burden of b19-related liver disease . | ### Summary:
: a clinical association between idiopathic liver disease and parvovirus b19 infection has been observed .
fulminant liver failure , not associated with other liver - tropic viruses , has been attributed to b19 in numerous reports , suggesting a possible role for b19 components in the extensive hepatocyte cytotoxicity observed in this condition . a recent report by abe and colleagues ( int j med sci .
2007;4:105 - 9 ) demonstrated a link between persistent parvovirus b19 genotype i and iii infection and fulminant liver failure .
the genetic analysis of isolates obtained from these patients demonstrated a conservation of key amino acids in the nonstructural protein 1 ( ns1 ) of the disease - associated genotypes . in this report
we examine a conserved residue identified by abe and colleagues and show that substitution of isoleucine 181 for methionine , as occurs in b19 genotype ii , results in the reduction of b19 ns1-induced cytotoxicity of liver cells .
our results support the hypothesis that in the setting of persistent b19 infection , direct b19 ns1-induced cytotoxicity may play a role in idiopathic fulminant liver failure . |
<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 32-year - old man from thailand was referred to the emergency department of hadassah hebrew university hospital at mount scopus on july 31 , 2008 , with newly diagnosed diabetes and fever .
he reported 23 weeks of fatigue , chills , night sweats , and a weight loss of 25 kg in the past 2 months .
the first abscess , in the right axilla , had been drained in may 2008 .
the second abscess , in the upper right abdominal wall , had been drained in july 2008 .
the patient , an agricultural worker , arrived in israel in november 2007 and was employed at a rural settlement in the southern jordan valley .
he came from a village in northeastern thailand where he had worked in rice and sugar cane farming . at the time of admission
physical examination showed mild cervical lymphadenopathy , nontender hepatomegaly , and healing wounds from the abscess drainage procedures .
laboratory results showed hyperglycemia ( glucose level 19.4 mmol / l ) , normocytic anemia with normal leukocyte and platelet counts , an erythrocyte sedimentation rate of 105 mm / h , and moderately elevated levels of alkaline phosphatase and -glutamyl transferase .
multiple abscesses were seen in the spleen , lungs , superior pole of the right kidney , prostate gland , and right foot ( figure ) .
a bone scan confirmed osteomyelitis of the right medial malleolus , calcaneus , and first metatarsus .
computed tomography images showing multiple abscesses in the right lung ( a ) , spleen and upper pole of the right kidney ( b ) , prostate gland ( c ) , and plantar aspect of the right foot ( d ) ( arrows ) of the patient .
a diagnosis of melioidosis had been considered from the outset in view of clinical findings of multiple abscesses in a patient with diabetes from a disease - endemic area . a blood culture ( bactec+ aerobic / f ; becton , dickinson and company , sparks , md , usa ) yielded a nonfermentative , oxidase - positive , motile , colistin - resistant , gram - negative bacilli that showed dry wrinkled colonies . the api 20 ne profile ( api ;
biomrieux , durham , nc , usa ) was 1556577 , which suggested esculin - positive b. pseudomallei .
molecular confirmation was achieved by bidirectional sequencing of a 1.7-kb amplicon specific for the 16s rrna gene , which was amplified by pcr and primers f229 and r1908 ( 6 ) .
fj426359 ) with the same primers showed the known single basepair transition ( c / t ) at position 75 that distinguishes b. pseudomallei from b. mallei , the agent of glanders ( 6 ) .
mics were 0.75 mg / l for trimethoprim and 14.25 mg / l for sulfamethoxazole ( etest ; ab biodisk , solna , sweden ) .
a urine culture was positive for b. pseudomallei , and throat and splenic abscess aspirate cultures were negative . the patient s first abscess developed 6 months after his arrival in israel , which attests to a long incubation period or prolonged latency after initial asymptomatic infection .
treatment with ceftazidime ( 2 g intravenously 4/d ) and trimethoprim / sulfamethoxazole ( 1,920 mg orally 2/d ) for 4 weeks resulted in gradual defervescence .
the patient was discharged with instructions to take trrimethoprim / sulfamethoxazole ( 1,920 mg orally 2/d ) and doxycycline ( 100 mg orally 2/d ) for an additional 20 weeks .
b. pseudomallei infection has been regarded as an occupational hazard for clinical microbiologists ( 79 ) .
although risk for laboratory - acquired infection is relatively low ( 7 ) , the nature of the disease demands special precautions in dealing with its causative organism . with recent designation of b. pseudomallei as a select agent by the centers for disease control and prevention ( www.cdc.gov/od/sap )
, it has been proposed that biosafety level 2 practices , which were advised for clinical diagnostic work ( 10 ) , be replaced by stricter safety practices ( 11 ) .
accordingly , a risk assessment was performed , and 4 persons who had handled the cultures outside a biologic safety cabinet were offered postexposure chemoprophylaxis with trimethoprim / sulfamethoxazole ( 1,920 mg orally every 8 h ) for 3 weeks ) ( 11 ) .
the frequency of rashes was worrisome : rashes developed in 2 persons ( 1 elected to complete the course of doxycycline [ 100 mg orally 2/d for 3 weeks ] and 1 stopped treatment after 10 days ) .
serum samples from 10 staff members who had had any contact with the cultures were collected within 23 days of exposure and after 68 weeks and tested by using an indirect hemagglutination test at mahidol university in bangkok .
all serologic test results were negative , an outcome consistent with findings of a published report ( 8) .
many workers ( 10,600 in 2007 ) from thailand have been employed in agriculture in israel ( 12 ) .
cases of melioidosis may not have been detected until the present patient because routine preemployment medical screenings may have excluded persons with the disease from entry into israel or unfamiliarity with the disease led to underdiagnosis .
migration of populations requires awareness regarding unforeseen diseases , as recently highlighted in a clinical problem - solving exercise ( 13 ) .
if one considers the abscesses in our patient , melioidosis would have likely been diagnosed earlier had this patient remained in thailand . in any case , if the routine practice of culturing pus from his abscesses had been followed , the diagnosis might have been made earlier .
this finding is a reminder to physicians that they should adhere to basic clinical guidelines .
conversely , clinical evidence and close cooperation of ward physicians , the infectious disease service , and the laboratory staff likely expedited identification of the organism .
the diagnosis of melioidosis in a region where this disease is not endemic depends on physician awareness and laboratory capability . in the patient
reported here , clinical suspicion , suggested by multiple visceral abscesses , preceded microbiologic confirmation , which was expedited by internists and the infectious disease service .
clinical microbiology laboratories worldwide should prepare for dealing with b. pseudomallei and include it in the workup of unusual nonfermentative , colistin - resistant , gram - negative bacilli , particularly in workers from thailand or other melioidosis - endemic countries .
the issue of chemoprophylaxis for persons with laboratory exposures , and its potential for adverse events , requires careful immediate decision making , especially if one considers the rarity of this albeit disabling disease among laboratory staff . | ### Summary:
: in 2008 , melioidosis was diagnosed in an agricultural worker from thailand in the southern jordan valley in israel . he had newly diagnosed diabetes mellitus , fever , multiple abscesses , and osteomyelitis .
burkholderia pseudomallei was isolated from urine and blood .
four of 10 laboratory staff members exposed to the organism received chemoprophylaxis , 3 of whom had adverse events . |
<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:
: residents living in the surrounding area of a large steel plant located near the dutch town of ijmuiden have been concerned about health effects from plant emissions for some time .
this led to studies into the acute effects of air pollution in the vicinity of the plant [ 1 , 2 ] . but concerns were augmented by a television documentary broadcast in may 2008 , which presented results from a study of metal concentrations in hair from children living in the area .
earlier , in 2007 , the community health service reported an increased lung cancer incidence for the region as a whole and for the nearby municipality of beverwijk in particular . in a large number of studies
the health effects of long - term exposure include , among , others lung cancer and mortality [ 521 ] .
we present the results from a study , which aims to investigate the spatial distribution of lung cancer incidence rates in a large area around the industrial site at a lower aggregation level than was previously available for studies into the health effects of the steel plant .
the study furthermore addresses the influence of smoking habits on lung cancer incidence and aims to assess the association between air pollution from the steel mill and observed lung cancer incidence rates .
the steel plant is located at the west coast of the netherlands in the ijmond region , covering a terrain of 750 hectares .
the plant was developed from 1920 onwards , first producing iron , later steel , and in addition aluminium .
the plant consists of 16 factories , including blast furnaces and coke ovens , and has its own harbour .
the selected study area surrounds the plant location to the south , east , and north ( figure 1 ) .
the study area was selected based on the service area of the community health service that originally investigated the public concern .
it is an area in which south - westerly winds prevail , which makes it plausible that plant emissions tend to distribute in a north - eastern direction .
the final study area consists of 17 municipalities and comprises 106 4-digit postcode areas with a total population just below 600,000 .
population data at the postcode level were available from statistics netherlands ( cbs ) stratified by age and sex .
historic emission data for the period 19501984 were obtained by combining the emission registration data from 1985 with historic production data .
polycyclic aromatic hydrocarbons ( pah ) , lead , and cadmium were the relevant and available air pollution indicators for the health effect under study .
the concentrations of these components were modelled for seven ( pah ) or eight ( metals ) consecutive periods from 1950 to 2007 for a 15 15 km model area at a 100 100 m resolution .
the period lengths varied from 3 to 23 years according to assumed invariance of emissions . from the geographical distributions of the concentrations , we calculated population density weighted average concentrations for each postcode situated ( for the greater part ) within the air pollution modelling area .
subsequently , the postcode areas were divided into four exposure categories based on quartiles .
figure 3 shows that the air pollution modelling area covers only part of the total study area ; the remaining 63 postcodes outside the modelling area constituted the fifth ( reference ) category .
effects of air pollution concentrations due to steel plant emissions were assumed to be negligible for these areas .
yearly lung cancer incidences ( icd10 c34 ) were obtained for a consecutive period of 12 years ( 19952006 ) from the comprehensive cancer centre amsterdam ( iknl ) . since 1989 , iknl maintains the only dutch oncology registry with a coverage of at least 95% of all cancer patients . the study period was started in 1995 as
age and gender specific population data at postcode level have become available since then . due to privacy regulations
, the observed number of lung cancer cases can not be reported below the postcode aggregation level , making this the aggregation level of choice for the analysis .
cancer risk is determined to a large extent by individual lifestyle factors such as smoking , diet , alcohol use , and obesity . for lung cancer risk , smoking behaviour is the dominant factor that might influence the results of this study . as no historical data on lifestyle factors were available at postcode level for the study area as a whole , we used socioeconomic status ( ses ) as a proxy to adjust for potential confounding .
ses categories constructed from level of income , education , and professional status are available for every 4 years since 1994 from the netherlands institute for social research .
we used percentile values for postcode areas based on the ranking order for ses of all postcode areas in the netherlands .
in addition , we obtained data from recent health surveys among 6,044 adults ( 1965 years ) and 5,691 elderly ( over 65 years ) for 2007 and 2008 on current and past smoking habits that was conducted for part of the study area ( 67 postcode areas ) by one of the community health services [ 24 , 25 ] . with this
survey data , the prevalence of current and past smoking was calculated per postcode area .
comparison of smoking prevalence and ses in a smaller part of the study area served as a check on the ability of the ses indicator to serve as a proxy for the differences in smoking behaviour between postcodes .
the expected number of lung cancer cases per postcode area was calculated through indirect standardization , based on the age and gender distribution of the population in a postcode and using the age and gender distribution of the lung cancer cases for the whole study region as the reference population .
as second step , a poisson regression model with indicator variables for each year was applied .
this model was subsequently extended to a bayesian hierarchical poisson regression model with a conditional autoregressive spatial correlation structure to determine spatially smoothed expected incidences [ 2628 ] . as a fourth step
maps of spatially smoothed standardized incidence ratios of observed and expected rates ( sir ) for the postcode areas were produced to assess the spatial pattern of lung cancer incidence for the population as a whole as well as for men and women separately .
to assess the association between air pollution indicators from the steel mill and observed lung cancer incidence rates , the 5 exposure categories for pah and cadmium were added to separate regression models .
we evaluated the effect of exposure on lung cancer incidence as relative risk ( rr ) . to evaluate potential residual confounding by smoking after adjustment for ses
, we determined whether a relation between exposure and smoking was present in part of the study area and whether this relationship still existed after adjusting for ses .
the average yearly population for the area consisted of 290,160 men and 303,860 women , while the average population within the postcodes amounted to 5,600 ranging from approximately 100 inhabitants up to almost 16,000 inhabitants .
the total number of lung cancer cases during the 12-year period was 3,029 for men and 1,388 for women ( 4,417 cases in total ) .
the yearly lung cancer incidence for the population in the study area was on average 5% lower than for the total population in the netherlands .
the distribution of the standardized incidence ratios ( sir ) and the effect of spatial smoothing are shown in table 1 .
after spatial smoothing , lung cancer showed significant increases in the sir of up to 40% in postcode areas in 2 municipalities located within 5 km from the industrial area .
similar increases were seen in parts of an urban area in the southern part of the study area further away from the industrial complex ( figure 2 ) .
there was very little or no discernible difference in ranking of postcode areas over time for both pah and metal concentrations .
similarly , there was little or no discernible difference in ranking of postcode areas between lead and cadmium concentrations .
therefore , analyses were performed using average data from a single time period ( 19721994 ) for pah and cadmium only .
the exposure categories for pah and cadmium did not exactly coincide due to different locations of the emission sources of pah and cadmium at the plant site . on the left side ,
figure 3 shows the geographical distribution of the modeled average pah concentrations for the period 19721994 and the location of the modelling area within the total study area .
the right side of figure 3 shows how the postcodes that are located completely or partly within the modelling window were assigned to the four exposure categories based on the average pah concentrations of the postcodes .
the distribution of the ses categories ( quintiles ) across the study area is shown in figure 1 .
on average , the ses scores in the study area were 8% lower than within the netherlands as a whole .
however , the ses scores covered almost the full scale ranging from the 5th to the 99th percentile .
ses scores for a single point in time could be used in the analysis because ses ranking of the postcodes hardly varied over the years during the study period ( 19952006 ) . the relative risks ( rr ) for lung cancer in postcodes within the lowest ses quintile compared to postcodes within the highest ses quintile were 1.59 ( 95%ci : 1.361.85 ) for men and 1.83 ( 95%ci : 1.442.29 ) for women . over the twelve - year study period ( 19952006 ) , ses ranking for postcode areas varied little over the years .
the pah exposure range , average population per year during the study period , and the total number of lung cancer cases are given in table 2 for each exposure category .
the table also shows the rr for lung cancer in each exposure category and the effect of smoothing and correction for ses on the rr .
the rr to develop lung cancer for those living in postcode areas in the highest pah exposure category compared to those living outside the exposure modelling area is 1.35 ( 95%ci : 1.231.48 ) .
the effect size diminishes slightly after applying spatial smoothing and adjustment for ses resulting in a rr of 1.21 ( 95%ci : 1.011.40 ) for men and women combined .
the rr in the highest exposure category is 1.22 ( 95%ci : 1.021.50 ) for men and 1.16 ( 95%ci : 0.871.50 ) for women in the model taking into account spatial smoothing and adjustment for ses .
the sir for lung cancer at postcode level after correction for ses is presented in figure 4 .
compared to figure 2 , the number of postcodes with a sir that is higher than expected is reduced .
the rr in the highest exposure category decreased from 1.34 ( 95%ci : 1.211.48 ) to 1.23 ( 95%ci : 1.031.50 ) after adjustment for ses and applying spatial smoothing for men and women combined .
again the results for men and women separately were comparable : 1.22 ( 95%ci : 1.011.50 ) for men only and 1.26 ( 95%ci : 0.941.70 ) for women only .
statistically significant elevated rrs due to exposure to air pollution from the industrial area were only found in the highest exposure category . as ses
can only serve as a proxy for smoking behaviour , potential residual confounding was further analyzed using an external data source on smoking habits , which covers only part of the study area and which was collected by one of the community health services after the time window of our study . in the highest air pollution exposure category , among women younger than 65 years of age , the odds ratio ( or ) for current smoking after adjusting for ses is 1.34 ( 95%ci : 1.091.64 ) , indicating that the prevalence of female smokers in this air pollution exposure category is higher than in the reference area and even higher than could be expected on the basis of lower ses .
in addition , in the highest air pollution exposure category among men of 65 + years of age an increased or after adjusting for ses of 1.82 ( 95%ci : 1.202.75 ) was observed for ever smoking .
in this study , we found that the sir for lung cancer was up to 40% higher than average in postcode areas in two municipalities in the proximity of the industrial terrain of a steel plant . with a total number of over 4,000 lung cancer cases over a period of twelve years , this study was relatively large in comparison to similar research from other scientific publications .
the first concerned the mortality risk of residents living near 22 coke plants in england , scotland , and wales over the period 19811992 and reported a small but significant excess mortality risk of 3% for residents living within 2 kilometres of the coke plants , after correction for ses .
the second describes lung cancer risks due to a coke oven plant near genoa , northern italy .
only a marginal excess risk was found in the exposed area compared to the two reference areas . published ecological studies with a smaller number of cases
tend to report higher relative risks than we found , albeit with much larger confidence intervals .
extensive research has been carried out around the steel foundries in armadale , bathgate , and kirkintilloch in scotland using both ecological and case - control study designs [ 15 , 16 , 20 , 21 , 29 ] .
the researchers attributed the increased cancer mortality risk that was found to a change in production process of the plants in the sixties .
due to the small number of cancer cases this was difficult to confirm using the available statistical methods at the time .
later research did indeed find a lung cancer cluster using more advanced statistical methods .
ecological research around the large complex of steel and petrochemical plants near teesside indicated increased lung cancer mortality over the period 19811991 in areas with increased exposure to air pollution [ 9 , 18 ] .
this was confirmed by a subsequent case - control study that found , after correction for confounding factors , a rr of 1.83 ( 95%ci : 0.824.08 ) for women living more than 25 years near heavy industry and 1.10 ( 95%ci : 0.961.26 ) for women living there more than 10 years .
similar ecological research near a coke plant in south tyneside over the period 19811989 did not show elevated lung cancer risks .
however , this factor is difficult to take into account using an ecological study design .
it was not possible to assess and account for the migration patterns of the population in our study .
archer studied lung cancer mortality risks in 3 communities in utah and estimated an increase of 3040% due to air pollution from a steel factory over the period 19501987 .
however , a similar study carried out in the same area did not find increased mortality risks after standardizing for smoking behaviour .
both studies have been found sensitive for the way confounding factors were taken into account and the construction of control areas .
several studies have been carried out in sydney ( nova scotia , canada ) around a coke plant and steel foundry [ 6 , 7 , 13 ] . over a period of 45 years ,
mortality in sydney was higher for breast and intestinal cancer compared to canadian reference figures . in three highly exposed areas near the plants ,
an increased lung cancer risk was found with a standard mortality ratio of 1.41 for men ( 95%ci : 1.111.77 ) and 1.76 for women ( 95%ci : 1.132.63 ) .
a subsequent case - control study could not confirm these findings due to the small number of cases that could be reached .
older studies do not correct for ses . those studies that do correct for ses or smoking habits like in our study find similar decreases in relative risks .
a few case - control studies have been published [ 6 , 12 , 16 ] .
the latter was the only study that produced information on relative risks for lung cancer in relation to living near an industrial area including a steel plant .
for 204 female lung cancer cases and 339 controls they found a rr for lung cancer of 1.83 ( 95%ci : 0.824.08 ) at 25 years of residence and of 1.10 ( 95%ci : 0.961.26 ) at 10 years of residence . the pah and cadmium concentrations being modelled on the basis of emission data introduce uncertainty in the estimated absolute levels of historical environmental concentrations . as we were interested in the contrast in health effects between high and low exposed areas ,
the relative ranking of the postcode areas within the study area is of more importance than the absolute levels of the pollutant concentrations .
this still leaves the possibility of exposure misclassification of postcodes due to uncertainties in the emission data and the modelling exercise , especially at larger distances from the industrial site where meteorological and model assumptions play a larger role on the outcome of the emission model .
since the observed effects only occur in the highest exposure category , the validity of the exposure contrast between the reference and the highest exposure category is most critical .
as we expect the least misclassification in the highest exposure category , the misclassification in the reference category is the most relevant .
however , as the reference category is very large consisting of 62% of the study population and 60% of the cancer cases , it is unlikely that misclassification of postcodes in this category will affect the baseline incidence rate in the reference category and thereby the rr .
the available data for the pollutants show a high degree of correlation in concentration across time and space . because of this correlation , it is not possible to distinguish between individual effects of each pollutant .
the data for pah and cadmium used must therefore be regarded as representative for historical exposure to the total air pollution from the steel plant .
we did not investigate alternative sources of air pollution , such as other nearby industries or shipping . in a sensitivity analysis ( not presented here ) , we investigated levels of air pollution from no2 and pm10 , which can be attributed to various local sources [ 3133 ] .
we found no relation between these air pollution levels and the increased lung cancer incidences .
as these concentrations of no2 and pm10 date from the start of this century , we can not preclude that earlier air pollution from local sources may have contributed to the increased lung cancer risks found . if historical pollution from other sources was correlated with the pah and cadmium concentrations from the steel plant which we used , it is possible they also contributed to the resulting increased risk . at the postcode level , ses was the only available confounder that corresponded with the studied time window of the incidence of lung cancer .
we are aware that the use of ses does not warrant a full adjustment for smoking habits .
it is also possible that changes in smoking habits over time did not correspond to the ses strata in the studied time window . where this leads to misclassification relating in any way to exposure , residual confounding may occur .
that residual confounding indeed may be present is suggested by results from an analysis of the only available additional smoking data , which covers only a part of the study area and which was collected after the time window of our study .
the analysis shows that in some age categories higher smoking percentages were found in the highest exposed postcode areas than were expected based on ses for these areas .
occupational exposure was not addressed in this study . as there is little difference between the relative risks found for both sexes ,
the increased lung cancer incidences are less likely to be explained by occupational exposure . the ecological epidemiological design of the study allowed us to analyse the geographical distribution of lung cancer incidence for a large population in relation to certain risk factors . the lack of information at the individual level means that conclusions can only be interpreted at the group level .
the increase in relative risk is an indication that possible past exposure to air pollution from the steel plant may have led to an increase in lung cancer incidence over the period 19952006 .
in addition , there is lack of information on past levels of pm10 and other components from other sources of air pollution .
contribution of these other factors to the increase in relative risk can therefore not be excluded .
we observed an increased lung cancer incidence in certain postcode areas near the steel plant , after adjustment for ses . in the areas in which the highest historical exposure to pah and cadmium occurred ,
lung cancer incidence after adjustment for ses was increased by 21% over the average incidence for the study area .
we were unable to ascertain that adjustment for ses fully compensates for the effect of smoking . due to the possible
residual confounding of smoking and the limited availability of and uncertainties in the historical exposure data , we can not indisputably conclude that past emissions from the steel plant have contributed to an increased risk of lung cancer . | ### Summary:
: we studied the spatial distribution of cancer incidence rates around a large steel plant and its association with historical exposure .
the study population was close to 600,000 .
the incidence data was collected for 19952006 . from historical emission data the air pollution concentrations for polycyclic aromatic hydrocarbons ( pah ) and metals were modelled .
data were analyzed using bayesian hierarchical poisson regression models .
the standardized incidence ratio ( sir ) for lung cancer was up to 40% higher than average in postcodes located in two municipalities adjacent to the industrial area . increased incidence rates could partly be explained by differences in socioeconomic status ( ses ) . in the highest exposure category ( approximately 45,000 inhabitants ) a statistically significant increased relative risk ( rr ) of 1.21 ( 1.011.43 ) was found after adjustment for ses .
the elevated rrs were similar for men and women .
additional analyses in a subsample of the population with personal smoking data from a recent survey suggested that the observed association between lung cancer and plant emission , after adjustment for ses , could still be caused by residual confounding .
therefore , we can not indisputably conclude that past emissions from the steel plant have contributed to the increased risk of 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:
: intra - articular adhesion after knee surgery is a common and serious complication and is a challenge problem for orthopedic surgeons .
the formation of intra - articular adhesions can lead to severe knee biomechanical change and dysfunction such as arthralgia , stiffness , cartilage degeneration , and subsequent pain , and thus leads to the failure of the surgery .
a variety of methods have been developed to prevent intra - articular adhesions in animal models and humans , including arthroscopic lysis of adhesions , intra - articular and/or mitomycin c application , continuous corticosteroid administration , and hyaluronan derivative gel [ 48 ] . however , none of these methods have achieved complete success . verapamil ( vp ) , a widely applied calcium channel blocker , can prevent synthesis / secretion of extracellular matrix molecules , including collagen , fibronectin , and glycosaminoglycans .
recently , based on clinical and experimental results , vp is reported to be an excellent choice as a scar modulator [ 911 ] . also , some studies have indicated vp s multiple effects , such as anti - inflammation , anti - fibrosis , anti - scar , anti - cancer , and neuro - protection [ 1115 ] .
intra - articular joint adhesion formation , being closely related to inflammatory response and scar formation , has a similar formation mechanism with keloid [ 1113 ] .
thus , the present research was designed . in the present study with knee operative rabbits ,
vp was used to investigate its efficacy on the prevention of intra - articular adhesion . specifically , we performed macroscopic assessment , analysis of histology , and hydroxyproline content .
we hypothesized that topically applied vp could be a useful preventive approach for reducing intra - articular adhesion , which could be tested in future clinical trails .
a total of 40 healthy adult new zealand white rabbits ( mean weight 4.0 kg ) were purchased from the radiation study institute animal center , tianjin , china . the present research was approved by the tianjin medical university medical ethics committee . according to the principles of both the european communities council directive ( 86/809/eec ) and international laboratory animal care ( ilac ) ,
animals were housed in the laboratory equipped with full - time staff , constant 20 to 25c room temperature , a 12-hour light - dark cycle , and accessible clean food and water ad libitum . before the experiment ,
animals were randomly divided into 4 groups ( 10 rabbits in per group ) according to the different treatments : 1 ) 1mg / ml vp treatment group ; 2 ) 2.5 mg / ml vp treatment group ; 3 ) 5 mg / ml vp treatment group ; 4 ) control group ( vehicle treatment group , vehicle composition : 5% propylene glycol , 50% alcohol , and 45% distilled water ) .
cal - ex ii solution for decalcification and dehydration was purchased from thermo fisher scientific ( waltham , ma , usa ) .
the rabbit knee intra - articular adhesion model was performed according to the previous protocol .
after induction of anesthesia by urethane ( 20% , intravenous injection ) , the fur around the left knee joint was shaved .
the knee was opened , and the lateral and the medial sides of the femoral condyle were exposed . with a dental burr operated on both sides of the femoral condyle without destroying the articular cartilage , the cortical bone ( approximately 1010 mm squares )
was removed until the exposure of the cancellous bone underneath . verapamil ( 1 mg / ml , 2.5 mg / ml , and 5 mg / ml separately diluted in vehicle ) or vehicle was administered to the operative sites with cotton for 5 min separately , then the cotton was removed from the surgical field . immediately , the operative site was irrigated with saline to eliminate surplus vp .
then the site was sutured surgically . to reduce the risk of infection , the animals were postoperatively given antibiotic ( baytril ; bayer ag leverkusen ) for 5 days . employing kirschner wires , the surgical limbs were subjected to extra - articular knee - joint immobilization in the full flexed position for 4 weeks .
all the animals were individually housed in the aforementioned condition . selecting 3 rabbits randomly per group , macroscopic evaluation was performed 4 weeks post - surgery .
the surgical knee was reopened with re - anesthesia , and the presence and severity of intra - articular adhesions was evaluated , with the results based on the visual scoring system ( table 1 ) [ 13 ] .
we measured the hydroxyproline content ( hpc ) in the rabbits used for macroscopic assessment .
with 6 mol / l hcl , the samples were lyophilized , ground , and hydrolyzed at 130c for 12 hours . using methyl red as the indicator , the samples were then neutralized with naoh .
after incubation for 20 minutes at room temperature , 1 ml of -dimethylaminobenzaldehyde was added to the standards and samples .
finally , based on a standard curve constructed with serial concentrations of commercial hydroxyproline , the hydroxyproline content of scar tissue was obtained .
after euthanizing with an overdose of urethane , the entire knee joints , including all fibrotic adhesive scar tissue and connective tissue , were removed .
after decalcification and dehydration with cal - ex ii solution for 1 week , samples were paraffin - embedded , and 5-m axial sections of the sample were made .
six odd - numbered sections from each sample were stained in masson s trichrome staining .
fibrous adhesion was determined under the help of a light microscope ( leica cm3050s , germany ) .
presence of fibrous adhesions was accepted as positive if the fibers were observed at the surface of the knee articular cartilage .
six even - numbered sections from each sample were stained with hematoxylin - eosin ( h&e ) .
fibroblast count in every section was defined as the average count from 3 different fields randomly selected at the margins and in the middle of the decorticated sites within every section . to further quantify the density of fibroblasts
data are expressed as mean standard error of mean ( sem ) values of the mean , median , and minimum - maximum .
differences among groups were assessed with one - way analysis of variance ( anova ) using the spss 13.0 statistical package ( spss inc . ,
a total of 40 healthy adult new zealand white rabbits ( mean weight 4.0 kg ) were purchased from the radiation study institute animal center , tianjin , china . the present research was approved by the tianjin medical university medical ethics committee . according to the principles of both the european communities council directive ( 86/809/eec ) and international laboratory animal care ( ilac ) ,
animals were housed in the laboratory equipped with full - time staff , constant 20 to 25c room temperature , a 12-hour light - dark cycle , and accessible clean food and water ad libitum . before the experiment ,
animals were randomly divided into 4 groups ( 10 rabbits in per group ) according to the different treatments : 1 ) 1mg / ml vp treatment group ; 2 ) 2.5 mg / ml vp treatment group ; 3 ) 5 mg / ml vp treatment group ; 4 ) control group ( vehicle treatment group , vehicle composition : 5% propylene glycol , 50% alcohol , and 45% distilled water ) .
cal - ex ii solution for decalcification and dehydration was purchased from thermo fisher scientific ( waltham , ma , usa ) .
the rabbit knee intra - articular adhesion model was performed according to the previous protocol .
after induction of anesthesia by urethane ( 20% , intravenous injection ) , the fur around the left knee joint was shaved .
the knee was opened , and the lateral and the medial sides of the femoral condyle were exposed . with a dental burr operated on both sides of the femoral condyle without destroying the articular cartilage , the cortical bone ( approximately 1010 mm squares )
verapamil ( 1 mg / ml , 2.5 mg / ml , and 5 mg / ml separately diluted in vehicle ) or vehicle was administered to the operative sites with cotton for 5 min separately , then the cotton was removed from the surgical field . immediately , the operative site was irrigated with saline to eliminate surplus vp .
the animals were postoperatively given antibiotic ( baytril ; bayer ag leverkusen ) for 5 days . employing kirschner wires , the surgical limbs were subjected to extra - articular knee - joint immobilization in the full flexed position for 4 weeks .
selecting 3 rabbits randomly per group , macroscopic evaluation was performed 4 weeks post - surgery .
the surgical knee was reopened with re - anesthesia , and the presence and severity of intra - articular adhesions was evaluated , with the results based on the visual scoring system ( table 1 ) [ 13 ] .
we measured the hydroxyproline content ( hpc ) in the rabbits used for macroscopic assessment .
the hpc was examined using a previously described method . with 6 mol / l hcl ,
the samples were lyophilized , ground , and hydrolyzed at 130c for 12 hours . using methyl red as the indicator
after incubation for 20 minutes at room temperature , 1 ml of -dimethylaminobenzaldehyde was added to the standards and samples .
finally , based on a standard curve constructed with serial concentrations of commercial hydroxyproline , the hydroxyproline content of scar tissue was obtained .
after euthanizing with an overdose of urethane , the entire knee joints , including all fibrotic adhesive scar tissue and connective tissue , were removed .
after decalcification and dehydration with cal - ex ii solution for 1 week , samples were paraffin - embedded , and 5-m axial sections of the sample were made .
six odd - numbered sections from each sample were stained in masson s trichrome staining .
fibrous adhesion was determined under the help of a light microscope ( leica cm3050s , germany ) .
presence of fibrous adhesions was accepted as positive if the fibers were observed at the surface of the knee articular cartilage .
six even - numbered sections from each sample were stained with hematoxylin - eosin ( h&e ) .
fibroblast count in every section was defined as the average count from 3 different fields randomly selected at the margins and in the middle of the decorticated sites within every section . to further quantify the density of fibroblasts ,
data are expressed as mean standard error of mean ( sem ) values of the mean , median , and minimum - maximum .
differences among groups were assessed with one - way analysis of variance ( anova ) using the spss 13.0 statistical package ( spss inc . ,
the knee surgery was successfully performed on all rabbits and none of the rabbits died intra- or post - operatively , and no cutaneous necrosis , obvious adverse effects , or mortality in the rabbits in the post - operative period were observed .
macroscopic determination results suggested that weak or soft fibrous adhesion was observed around the surgical sites in the 5 mg / ml vp group ( visual score=0.860.34 ) .
moderate scar adhesion was seen in the surgical sites in the 2.5 mg / ml vp group ( visual score=1.440.39 .
however , tenacious and dense fibrous adhesion was seen around the surgical sites in the 1 mg / ml vp ( visual score=3.270.61 ) and control groups ( visual score=3.510.49 ) .
compared with the control group , the 5 mg / ml and 2.5 mg / ml vp group had significantly better visual score , and the 1 mg / ml vp group showed no significant result ( figure 1 ) .
the hydroxyproline contents of the intra - articular scar for the 4 groups are shown in figure 2 . in the 5 mg / ml vp group ,
the hydroxyproline content was 27.545.28 g / mg . compared with those in the 2.5 mg / ml vp group ( 36.393.89 g / mg , p<0.001 ) , 1 mg / ml vp group ( 51.393.35 g / mg , p<0.001 ) , and control group ( 57.324.17 g / mg , p<0.001 ) , it showed significantly less .
the content in the 2.5 mg / ml vp group was lower than those in the 1 mg / ml vp group ( p<0.001 ) and control group ( p<0.001 ) .
no significant difference in hydroxyproline content was seen between the control group and the 1 mg / ml vp group ( p=0.194 ) ( figure 2 ) . with little or no adhesions ,
loose and thin scar tissues were found in the 5 mg / ml vp group ( figures 3a , 4a ) . in the 2.5 mg / ml vp group ,
moderate adhesion tissues were seen around the operative sites , and the density of fibroblasts significantly decreased compared with those of the 1 mg / ml group and control group ( figures 3b , 4b ) . in the control group and 1 mg / ml vp group , dense adhesions and markedly fibrous scar tissues were seen around the operative sites ( figure 3c , 3d ) .
many fibroblasts were seen in the adhesion tissue around the operative sites ( figure 4c , 4d ) .
figure 4 shows the fibroblast density situations of the intra - articular scar tissue in the 4 groups . for fibroblast
counting in scar tissue , the number in the 5 mg / ml vp group was ( 35.2611.71 ) , significantly less than in the 2.5 mg / ml vp group ( 44.8220.36 , p=0.005 ) , 1 mg / ml vp group ( 68.3222.49 , p<0.001 ) , and control group ( 71.9219.38 , p<0.001 ) .
there were fewer fibroblasts in the 2.5 mg / ml vp group than in the control group ( p=0.001 ) and 1 mg / ml vp group ( p=0.001 ) .
the fibroblast number in the 1 mg / ml vp group and control group showed no significant difference ( p=0.302 ) . in order to be more definitive , an additional immunohistochemistry analysis for vimentin
figure 5 shows the density of vimentin in the intra - articular scar tissue of the 4 groups . in the 5 mg / ml vp group ,
the positive vimentin number in intra - articular scar tissue was 20.198.32 , significantly less than those in the 2.5 mg / ml vp group ( 29.3411.47 , p=0.004 ) , 1 mg / ml vp group ( 35.4919.33 , p<0.001 ) , and control group ( 44.2715.26 , p<0.001 ) .
the number of vimentin in the 2.5 mg / ml vp group was lower than in the control group ( p=0.001 ) and 1 mg / ml vp group ( p=0.001 ) .
moreover , compared with that of the control group , no significant result was found in the 1 mg / ml vp group ( p=0.418 ) .
macroscopic determination results suggested that weak or soft fibrous adhesion was observed around the surgical sites in the 5 mg / ml vp group ( visual score=0.860.34 ) .
moderate scar adhesion was seen in the surgical sites in the 2.5 mg / ml vp group ( visual score=1.440.39 .
however , tenacious and dense fibrous adhesion was seen around the surgical sites in the 1 mg / ml vp ( visual score=3.270.61 ) and control groups ( visual score=3.510.49 ) .
compared with the control group , the 5 mg / ml and 2.5 mg / ml vp group had significantly better visual score , and the 1 mg / ml vp group showed no significant result ( figure 1 ) .
the hydroxyproline contents of the intra - articular scar for the 4 groups are shown in figure 2 . in the 5 mg / ml vp group ,
the hydroxyproline content was 27.545.28 g / mg . compared with those in the 2.5 mg / ml vp group ( 36.393.89 g / mg , p<0.001 ) , 1 mg / ml vp group ( 51.393.35 g / mg , p<0.001 ) , and control group ( 57.324.17 g / mg , p<0.001 ) , it showed significantly less .
the content in the 2.5 mg / ml vp group was lower than those in the 1 mg / ml vp group ( p<0.001 ) and control group ( p<0.001 ) .
no significant difference in hydroxyproline content was seen between the control group and the 1 mg / ml vp group ( p=0.194 ) ( figure 2 ) .
with little or no adhesions , loose and thin scar tissues were found in the 5 mg / ml vp group ( figures 3a , 4a ) . in the 2.5 mg / ml vp group ,
moderate adhesion tissues were seen around the operative sites , and the density of fibroblasts significantly decreased compared with those of the 1 mg / ml group and control group ( figures 3b , 4b ) . in the control group and 1 mg / ml vp group , dense adhesions and markedly fibrous scar tissues were seen around the operative sites ( figure 3c , 3d ) .
many fibroblasts were seen in the adhesion tissue around the operative sites ( figure 4c , 4d ) .
figure 4 shows the fibroblast density situations of the intra - articular scar tissue in the 4 groups . for fibroblast counting in scar tissue , the number in the 5 mg / ml vp group was ( 35.2611.71 ) , significantly less than in the 2.5 mg / ml vp group ( 44.8220.36 , p=0.005 ) , 1 mg / ml vp group ( 68.3222.49 , p<0.001 ) , and control group ( 71.9219.38 , p<0.001 ) .
there were fewer fibroblasts in the 2.5 mg / ml vp group than in the control group ( p=0.001 ) and 1 mg / ml vp group ( p=0.001 ) .
the fibroblast number in the 1 mg / ml vp group and control group showed no significant difference ( p=0.302 ) . in order to be more definitive ,
figure 5 shows the density of vimentin in the intra - articular scar tissue of the 4 groups . in the 5 mg / ml vp group ,
the positive vimentin number in intra - articular scar tissue was 20.198.32 , significantly less than those in the 2.5 mg / ml vp group ( 29.3411.47 , p=0.004 ) , 1 mg / ml vp group ( 35.4919.33 , p<0.001 ) , and control group ( 44.2715.26 , p<0.001 ) .
the number of vimentin in the 2.5 mg / ml vp group was lower than in the control group ( p=0.001 ) and 1 mg / ml vp group ( p=0.001 ) .
moreover , compared with that of the control group , no significant result was found in the 1 mg / ml vp group ( p=0.418 ) .
gradually , it has become widely accepted that the hyperplasia of fibrous tissue plays a clear role during the formation of intra - articular scar adhesion . after extensive literature reviews , among various agents studied to prevent intra - articular adhesion , mitomycin c ( mmc ) seems to be able to reduce the condition of fibrosis by inhibiting collagen synthesis in fibroblasts in both rats and rabbits .
previous research has shown that mmc prevents scar tissue formation by inhibiting fibroblasts proliferation , but due to its toxicity it is not widely used clinically .
some research attention has focussed on determining if topical application of mmc would increase the rate of infection .
potential abilities of vp that could reduce epidural scar adhesion and inhibit fibrotic cells proliferation of surgery sites were suggested in the present study .
multiple evaluations , including the hydroxyproline content evaluation , the histological analysis , the visual score system , and the density grade of fibrotic cells , suggested a good efficacy of vp in inhibiting intra - articular adhesion in rabbits .
previous studies reported the anti - fibrotic , anti - inflammatory , and anti - proliferative properties of vp employed in different fields [ 1115 ] . in the present study ,
previous research and the present results may indicate some possible mechanisms that make vp effective in preventing knee joint adhesion .
we hypothesize that the major mechanisms of vp in preventing intra - articular adhesion are its role on reducing fibrotic cells proliferation and down - regulating inflammatory activity .
undoubtedly , this needs further research . despite recent advances in the understanding of wound healing and scar formation ,
the treatment of intra - articular adhesion is still controversial . for the first time , in 1990 by lee and ping , vp clinically used collagen matrix in connective tissue remodeling .
subsequently , the literature reported vp to be a promising treatment for earlobe keloids , with a 55% cure rate .
a recent orthopedics report suggests that vp could be a good choice for inhibiting epidural fibrosis .
a recent hypothesis suggests that the use of platelet - rich plasma can promote the clinical healing of meniscal tears .
thus , the combination of vp and platelet - rich plasma is a potential strategy that needs to be tested . to the best of our knowledge ,
the present study is the first to investigate the suppressive effects of vp on intra - articular adhesion in rabbits .
further research on drug safety , safe and effective concentration , long - term effects , and possible adverse effects of vp are all needed before clinical trials can be performed .
in our rabbit model of knee surgery , intra - articular application of vp was able to decrease intra - articular adhesion formation after surgery .
we showed that vp could prevent rabbit intra - articular adhesion in a dose - dependent manner , and the highest concentration used in the study ( 5 mg / ml ) proved to be the most effective . | ### Summary:
: backgroundintra - articular adhesion after knee surgery is a common and serious complication that presents a challenging problem for orthopedic surgeons .
verapamil ( vp ) , a widely used calcium channel blocker , has been shown to prevent synthesis / secretion of extracellular matrix molecules .
the object of this study was to investigate the effects of vp on the prevention of joint adhesion in post - surgery rabbits.material/methodsa controlled double - blinded study was conducted in 40 healthy new zealand white rabbits divided randomly into 4 groups according to the treatment method , with 10 in each group : 1 ) 1 mg / ml vp treatment group ; 2 ) 2.5 mg / ml vp treatment group ; 3 ) 5 mg / ml vp treatment group ; 4 ) control group .
rabbits underwent surgery through the medial parapatellar approach and both lateral sides and the medial of the femoral condyle were surgically exposed . after treatment , the surgical limbs were subjected to extra - articular knee - joint immobilization in the full flexed position employing kirschner wires for 4 weeks.resultsthe knee surgery was successfully performed on all rabbits .
the rabbits were killed 4 weeks post - operatively .
the histological evaluation , hydroxyproline content , visual score , fibroblasts density , and vimentin expressional levels were conducted to assess the effect of vp on preventing joint adhesion.conclusionsin our rabbit model of knee surgery , intra - articular application of vp was able to decrease intra - articular adhesion formation after surgery .
vp could prevent rabbit intra - articular adhesion in a dose - dependent manner and the highest concentration used in the study ( 5 mg / ml ) proved to be the most effective . |
<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:
: this is a normal protective mechanism associated with any
lesion anywhere in the body .
usually the patients complain of a localized pain in the ocular
area of the affected cornea .
this is due to the ciliary spasm
secondary to the corneal neuronal reflex arc .
ciliary spasm
can be effectively relieved by use of cycloplegics such as
homatropine eye drops .
in addition , the pain is usually well
controlled once the topical medication brings the corneal
infiltrates under control . however
, if a patient complains of a sudden or severe increase
in pain , one needs to consider secondary glaucoma .
they include hypopyon and exudates on the endothelial
surfaces causing a block of the trabecular meshwork or
secondary trabeculitis in some cases of viral keratitis .
secondary glaucoma needs aggressive medical management
in the form of topical beta blockers and carbonic anhydrase
inhibitors ( dorzolamide ) with or without systemic carbonic
anhydrase inhibitors ( acetazolamide ) .
we prefer systemic
carbonic anhydrase inhibitors due to the potential toxicity of
topical inhibitors to the damaged corneal endothelium.1 sudden reduction of pain in a patient with an active
uncontrolled keratitis should be looked upon with suspicion
rather than relief .
many a times due to the extensive exudation
and/or accumulation of the medications ( especially antifungal ) ,
the underlying wound is hidden .
this can lead to a false sense
of security and the underlying thinning may be missed .
a
micro - perforation in the area of the corneal ulcer can lead to
natural drainage of the aqueous and relieve the intraocular
pressure .
however , the collapse of the anterior chamber
will lead to the formation of an adherent leukoma as well as
closure of the angle of the anterior chamber
. this will lead
to irreversible secondary angle closure glaucoma with poor
chances of visual rehabilitation .
however , if a patient complains of a sudden or severe increase
in pain , one needs to consider secondary glaucoma .
they include hypopyon and exudates on the endothelial
surfaces causing a block of the trabecular meshwork or
secondary trabeculitis in some cases of viral keratitis .
secondary glaucoma needs aggressive medical management
in the form of topical beta blockers and carbonic anhydrase
inhibitors ( dorzolamide ) with or without systemic carbonic
anhydrase inhibitors ( acetazolamide ) .
we prefer systemic
carbonic anhydrase inhibitors due to the potential toxicity of
topical inhibitors to the damaged corneal endothelium.1
sudden reduction of pain in a patient with an active
uncontrolled keratitis should be looked upon with suspicion
rather than relief .
many a times due to the extensive exudation
and/or accumulation of the medications ( especially antifungal ) ,
the underlying wound is hidden .
this can lead to a false sense
of security and the underlying thinning may be missed .
a
micro - perforation in the area of the corneal ulcer can lead to
natural drainage of the aqueous and relieve the intraocular
pressure .
however , the collapse of the anterior chamber
will lead to the formation of an adherent leukoma as well as
closure of the angle of the anterior chamber .
this will lead
to irreversible secondary angle closure glaucoma with poor
chances of visual rehabilitation .
the most common effect of a microbial infection of the cornea
is the necrotic changes of the stromal fibers .
. it can be the direct action of the
microbe in breakdown of the stromal fibers .
it can be indirect
action due to the endotoxins released due to the destruction of
the microbial cell wall by the antibiotics or the body defense
mechanisms .
it can also be due to autolysis induced by various
human enzymes like matrix metalloproteinases ( mmps ) that
are released due to an uncontrolled activation of the tissue
destruction mechanisms.3,4 the end result of all these mechanisms is the necrosis of the
tissue in the infected area .
if this is seen only due to the direct
action of the microbes , then the control of the infection will
limit the thinning .
thus , a regular watch on the corneal ulcer
( we usually recommend a follow - up visit at least 48 h apart in
ulcers < 3 mm and every 24 h in larger ulcers ) is necessary to
prevent such mishaps ( v agrawal , unpublished data ) . in infections due to gram - negative bacteria such as
pseudomonas , the risk of rapid corneal melt is unusually high .
these patients need to be seen as frequently as twice a day till
the ulcer begins to heal .
the reason to watch for a corneal melt is that an early melt
may respond to treatment and advanced melt is unlikely to
respond well ( v agrawal , unpublished data ) . in case of early melt ,
use of topical and systemic tetracycline
is believed to help.5,6 in addition , the use of tissue
glue and bandage contact lens can also be useful .
if the perforation is
larger than 2 mm , then the use of tissue glue is unlikely to
be adequate .
we have successfully used preserved amniotic
membrane as a multilayered application with tissue glue at
the wound edges to close such wounds .
this is a modification
of the method of hick et al.7 amniotic membrane also has
anti - collagenolytic properties and may help in stabilizing the
ocular surface .
perforations larger than 4 mm and up to 6 mm may need a
corneal patch graft to close the fistula .
total corneal melts have been managed with sclerokeratoplasty with
guarded results.8 in summary , corneal melts are best avoided by rigorous
observation and aggressive medical management .
in severe fungal infection , the descemets membrane can fail
to limit the infection to the corneal stroma .
alternatively , the
severe anterior chamber reaction secondary to the toxic effects
of the microbe can lead to a complete organized hypopyon
formation in the anterior chamber .
the use of cycloplegics has
been advocated but in our experience it may not be adequate .
in such cases ,
we have used the concept of anterior chamber
lavage to debulk the chamber and also reduce the infectious
load to help the medications act better . along with the lavage
with ringers lactate , there may be a need to remove the
organized fibrinoid material from the chamber .
the use of a
suitable antibiotic or antifungal agent in the lavage fluid is
acceptable.9
many a times one sees that the corneal ulcer is responding
to the medications for first 24 - 48 h. after this period , the
eye becomes significantly redder , there is lid edema and the
conjunctival surface too starts to stain with fluorescein .
however , it is more likely
to either be an allergic reaction to one of the medications being
used or the occurrence due to keratitis medicamentosa .
this
is differentiated from spreading infection by the fact that the
primary lesion size remains constant or shows improvement
despite all the adnexal changes . | ### Summary:
: infectious keratitis is a fairly common entity in india .
however while paying attention to the primary entity ,
the associated events may be overlooked .
enhanced pain usually suggests a worsening of the condition or
development of associated problems like secondary glaucoma .
however , contrary to logic , a sudden decrease
in pain is also liley to suggest a worsening , e.g. perforation of the corneal ulcer .
various such problems with
their management are outlined . |
<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:
: traumatic spinal cord injury ( sci ) is a complex , life - disrupting medical condition due to the detrimental effects on social , familiar , and personal life , which include in the majority of cases permanent paralysis due to the low regenerative capacity of the central nervous system ( cns ) .
sci triggers a series of interconnected mechanisms that can be divided into the primary and secondary injury .
the direct and immediate physical disruption of neurons , glial cells , and blood vessels makes up the primary injury . in turn , the secondary injury consists of a cascade of autodestructive cellular and molecular mechanisms that exacerbate the primary injury and lead to an enlargement of the initial area of trauma [ 14 ] .
several mechanisms take part in this latter phase of the injury , including vascular disruption , increased blood - spinal cord barrier permeability , ionic dysregulation , edema , excessive intracellular calcium concentration , glutamate excitotoxicity , lipid peroxidation , an autoreactive inflammatory reaction , and apoptosis .
ultimately , the sum of these processes causes cell death , demyelination , and axonal degeneration at the epicenter of injury and the surrounding regions . these cellular and molecular changes that occur early after sci alter gene expression profiles , which is characterized by a significant upregulation of genes with roles in transcription , inflammation , and signaling proteins .
evidence suggests that the consequent inflammation mediated by cytokines , growth factors , and related molecules plays a role in both the damage and repair of injured neural tissue [ 79 ] .
the critical balance between these processes plays a major participation in the progression and outcome of a neurodegenerative process .
cytokines encompass a large family of small signaling proteins involved in intercellular communication that are normally associated with the immune response and its modulation but have pleiotropic effects in the physiology of health and disease including cellular growth , survival , and differentiation .
these molecules , which can be classified as peptides , proteins , or glycoproteins , are secreted by numerous cells and can be grouped into a proinflammatory or anti - inflammatory category on the basis of the final balance of their effects . subsequently , growth factors are proteins synthesized by a wide variety of cells that stimulate cellular survival , chemotaxis , proliferation , and differentiation [ 11 , 12 ] .
the aim of this review is to expose the role of cytokines and growth factors within the pathogenesis of sci , since the study of these molecules could bring to light novel potential therapeutic targets that could reduce the degenerative processes that occur after sci .
the blood - cns vascular barriers consist of complexes of adherence junction proteins and tight junctions , astrocyte endfeet , perivascular microglia , pericytes , and continuous capillary endothelial cells embedded in the basement membrane that separate and protect the cns from metabolites and neurotoxic substances present in the systemic circulation [ 1315 ] .
this infrastructure allows the blood brain barrier ( bbb ) and blood spinal cord barrier ( bscb ) to regulate the transport of molecules , the interaction between the cns and the immune system , and helps maintaining homeostasis in the brain and spinal cord .
one of the earliest events ensuing traumatic sci is the disruption of the bscb by a mechanical force that destroys neural tissue and tears neuronal and endothelial cell membranes .
the resulting inflammatory response disturbs the microenvironment of the spinal cord , alters vascular permeability , facilitates the entry of peripheral immune cells , and exposes the adjacent noninjured tissue to potentially noxious molecules [ 16 , 17 ] .
these molecules include early inflammatory cytokines such as interleukin 1 ( il-1 ) and tumor necrosis factor ( tnf ) ; in addition , they might include nitric oxide ( no ) , reactive oxygen species ( ros ) , elastase , and matrix metalloproteinase-9 ( mmp-9 ) .
the importance of the bscb is evidenced by the positive correlation between increased barrier disruption and improved motor locomotion 14 days after sci [ 1820 ] .
an additional consequence of such disruption is a series of regulatory changes in the transport systems for selective cytokines that may induce regenerative or destructive effects . in particular
, there is an upregulation of the transport system of tnf after sci that remains saturable despite bscb disruption .
the increase of tnf takes place before other cytokines in sci and is mediated by the receptor - based transport composed by tnfr1 ( p55 ) and tnfr2 ( p75 ) .
tnf has a role in inflammation , myelin destruction , apoptotic neuronal cell death , and astrocyte toxicity .
nevertheless , this cytokine is also capable of stimulating neurite outgrowth , secretion of growth factors , and tissue remodeling .
it has been suggested that tnf has a dual role : deleterious in the acute phase , but beneficial in the chronic phase after sci .
similarly , leukemia inhibitory factor ( lif ) utilizes a transport system mediated by lifr ( gp190 ) , which is upregulated by barrier disruption , but remains saturable despite this event [ 21 , 23 ] .
lif is involved in the activation of microglia / macrophages and in the proinflammatory response in sci .
contrastingly , lif has been shown to prevent oligodendrocyte apoptosis in mice with sci after overhemisection , notably contralateral to the spinal cord lesion , through the induction of the jak / stat and akt signaling pathways as well as by potentiating the expression of the antiapoptotic molecule , ciap2 .
reduced oligodendrocyte apoptosis after sci with lif administration resulted in a substantial decrease in demyelination shown by the preservation of lamellated myelin surrounding viable axons and deposition of the degraded myelin basic protein .
the data suggest that lif signals survival in oligodendrocytes after sci , prevents the secondary wave of demyelination , and thereby reduces inhibitory myelin deposits and enhance locomotor recovery .
immediately after contusive sci , the rupture of the blood - cns barrier causes water to accumulate in the extracellular compartment and results in the production of neural tissue edema [ 26 , 27 ] .
this is a process that may aggravate the initial injury and result in paraplegia or even death .
the subsequent increment in vascular permeability and the formation of edema could also be in part mediated by the vascular endothelial growth factor ( vegf ) and proto - oncogene tyrosine - protein kinase ( src / c - src ) which exists downstream of vegf .
it is worth noting that administration of vegf has resulted in an increase in permeability of the bscb from the acute to chronic phase , which is interesting since it is regarded to be a component involved in angiogenesis , neurogenesis , and locomotor recovery . as the secondary injury progresses , this fluid accumulation in the cns becomes characterized by ionic imbalance , which consists of an increase in the intracellular concentration of na and ca , in conjunction with an elevated extracellular concentration of k and mg [ 3032 ] . consequently , the na and ca ions attract water molecules into the cell and cause edema .
the resulting fluid accumulation then propels the compression of adjacent tissues and the development of ischemia , which leads to more autodestructive phenomena such as free - radical production , lipid peroxidation , and inflammation .
it is important to note that the edema that occurs after contusive sci is directly related to the initial trauma and motor dysfunction experienced by the affected individual [ 27 , 33 ] .
astrocytes are the principal regulators of water transport in the cns , where they are additionally linked to the maintenance of ion homeostasis , spatial buffering of extracellular potassium , calcium signal transduction , adult neurogenesis , and neurotransmitter uptake and release [ 3436 ] . a molecule expressed in astrocyte endfeet , astrocyte processes , and the basolateral membrane of ependymal cells is aquaporin 4 ( aqp4 ) , the predominant water channel in the cns .
moreover , the absence of aqp4 has been shown to reduce proinflammatory cytokines in astrocytes such as tnf and interleukin-6 ( il-6 ) after cns injury .
it is important to mention that the role of aqp4 in the resolution of edema is still under debate .
nevertheless , evidence demonstrates that aqp4 has an essential role in the formation and distribution of edema and that it is intrinsically involved in the development of the inflammatory process after an insult to the cns . on the other hand ,
neurons regulate synaptic transmission and neural plasticity by the activation of membrane receptors and channels in adjacent neurons .
released neurotransmitters can bind to inhibitory ( gaba)ergic receptors or excitatory glutamate receptors such as amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid ( ampa ) , n - methyl - d - aspartate ( nmda ) , kainate , and metabotropic receptors . in the locomotor networks of the spinal cord , ca activated , apamin - sensitive k channels ( sk ) control the firing of constituent neurons and regulate the locomotor rhythm .
voltage - gated ca channels ( vgccs ) , such as n - type ca channels , are considered the main activators of sk channels , which during early development play a role in neurite outgrowth and functional neuromuscular synapse organization .
nmda receptors , besides controlling evoked neurotransmitter release , also play a role in the activation of sk channels in dendrites [ 39 , 40 ] .
sk channels have been found to regulate hippocampal synaptic plasticity , learning , and memory , particularly sk2 channels .
synaptic transmission involves ca and employs calmodulin ( cam ) dependent kinases ( camkiiv ) , protein kinase c , protein kinase a , ip3 kinase , ca - dependent phosphatase calcineurin b , cyclic amp phosphodiesterase , adenylyl cyclase , lca - dependent neuronal nitric oxide synthase ( nos ) , and calpains , which are ca activated proteases [ 42 , 43 ] . in the first few minutes following sci , oxidative stress , lipid peroxidation , and membranous deposition of protein aggregates take place .
these processes impair ca pumps and cell membrane channels , including those present in the endoplasmic reticulum .
this downregulation is evidenced by an increased concentration of cytosolic ca from extracellular pools and intracellular ca storages . in normal conditions , the energy - dependent ca buffering system within axons
however , when adenosine triphosphate ( atp ) is depleted by the excessive energy demands of demyelination , this normal ca buffering fails and the level of intracellular ca rises until it becomes toxic .
the result is the chaotic activation of processes such as proliferation , differentiation , apoptosis , and gene transcription in cells .
in addition to the before - mentioned channels , axons also have a high concentration of voltage - gated na channels spread along the length of their bodies .
thus , when axonal demyelination occurs , there is a dramatic increase in na influx into the cell during the action potential propagation .
the elimination of such an excess concentration of intracellular na can come at a steep metabolic expense in a similar fashion to ca removal , since the na / k atpase maintains the na electrochemical gradient by atp consumption [ 46 , 47 ] .
when atp levels fall below a certain threshold , there is a concomitant increase in the intra - axonal concentration of na and ca .
consequently , glutamate is released , and the na / ca exchanger , which normally pumped out 1 ca in exchange for 3 na , is reversed [ 46 , 47 ] .
it is also important to mention that the subsequent release of atp after the lesion increases in peritraumatic areas for 6 or more hours .
this excessive release of atp by the traumatized tissue after sci is followed by the activation of high affinity purinergic p2x receptors .
it is important to note that the p2x7 receptors may also contribute to the excessive influx of ca since they are upregulated in response to the atp release induced by sci .
this might explain why spinal cord neurons respond to atp with excessive firing , followed by irreversible increases in ca that end up in cell death [ 49 , 50 ] .
furthermore , p2x7rs have been associated with cells of the immune system that mediate cytotoxic cell death ( because of changes in transmembrane ion fluxes , swelling , and vacuolation ) and those that mediate inflammatory responses , including proinflammatory mediators such as il-1 and tnf [ 49 , 50 ] .
glutamate receptors are involved in the excitatory neurotransmission of the mammalian cns , where they participate in various changes in the efficacy of synaptic transmission , and induce excitotoxic damage in a variety of acute and chronic neurological disorders [ 51 , 52 ] .
the process of excitotoxicity refers to the excessive receptor activation by this excitatory amino acid that results in neuronal death .
just 15 min after sci , glutamate levels at the epicenter and surrounding regions become six times higher than physiological levels due to the overstimulation of ionotropic receptors and the massive increase of intracellular ca and na .
this glutamate influx provokes overexcitation and endotoxicity by the secondary increase of intracellular ca and the activation ca dependent signaling pathways as previously mentioned [ 5456 ] .
moreover , the augmented expressions of genes related to neurotransmitter receptors ( nmda , ampa , ach , gaba , glur , and kainate ) increase demyelination and oligodendrocyte destruction [ 57 , 58 ] .
an important mechanism for the reduction of excessive extracellular glutamate is the activity of glutamate transporters such as glial glutamate transporter 1 ( glt-1 ) and glutamate aspartate transporter ( glast ) , which are primarily expressed by astrocytes .
unfortunately , the excitotoxicity induced by the extracellular glutamate concentration is enhanced by the reduced uptake by astrocytes and the microglia release tnf , il-1 , and ros that exacerbated the neural damage .
tnf and il-1 have been shown to cause oligodendrocyte death when the latter are placed in coculture with both astrocytes and microglia .
both cytokines inhibit glutamate transporters in astrocytes and thus expose oligodendrocytes to an excessive glutamate concentration .
it is important to note that antagonists of ampa / kainate glutamate receptors such as nbqx ( 2,3-dioxo-6-nitro-7-sulfamoilbenzo(f)quinoxalina ) and cnqx ( 6-cyano-7-nitroquinoxaline-2,3-dione ) blocked il-1 toxicity towards oligodendrocytes .
first , microglia release this cytokine in the inflammatory response , which induces additional release of tnf. in turn , it causes the release of glutamate that acts on metabotropic receptors of microglia and stimulates more tnf release .
subsequently , astrocytes are stimulated to release glutamate , which is not effectively transported back into the soma .
lastly , the rise in the excitatory / inhibitory ratio causes the excessive ca entry and excitotoxic neuronal death previously described .
the consequent neuronal death caused by the excessive glutamate concentrations further stimulates microglia to remain in an active state , which includes the production and release of tnf in a vicious cycle .
tnf potentiates cytotoxicity by glutamate through an increased localization of glutamate receptors such as ampa and nmda while decreasing inhibitory gaba receptors on neurons , which explains why nbqx blocked tnf toxicity to oligodendrocytes .
spinal cord trauma results in the destruction of neurons , nerve fibers , glial cells , and blood vessels at the site of injury , where approximately 30% of neurofilament constitutive proteins are degraded in 1 h , and 70% are lost within 4 h after the injury .
proteins such as cathepsin b , y , and s , members of the cysteine lysosomal proteases and papain superfamily , have been linked to neurofilament destruction .
this link results from the fact that cathepsin b can degrade myelin basic protein , cathepsin y can produce a bradykinin , and cathepsin s can degenerate extracellular molecules through inflammatory mediators . in particular , only cathepsin s is able to retain its activity after prolonged incubation at neutral ph , more than 24 h [ 64 , 65 ] .
the expression of this protease is restricted to cells of the mononuclear phagocytic system such as microglia and macrophages .
a basement membrane heparan sulfate proteoglycan ( hspg ) , perlecan , which was found to promote mitogenesis and angiogenesis , can be degraded by cathepsin s in vitro .
hspgs have roles in adhesion , protease binding sites , and growth factor regulation as is the case for basic fibroblast growth factor ( bfgf ) .
furthermore , cathepsin s degrades laminin , fibronectin , collagens , and elastin at acidic or neutral ph .
it is known that tnf , interferon- ( ifn ) , il-1 , and granulocyte macrophage colony stimulating factor ( gmcsf ) stimulate the release of active cathepsin s into an environment with a neutral ph .
subsequently , a change in lipid metabolism and the homeostasis of lipid mediators is an alternate route by which genes are thought to modulate the susceptibility of nervous tissue to trauma .
interestingly , altered protein cleavage , one of the main driving forces of protein aggregation in neurodegenerative disorders , can be further enhanced by trauma occurring in the presence of specific lipid - binding proteins , important molecules in charge of the distribution of lipids and the transport of cholesterol among cells in the cns .
apolipoprotein e ( apoe ) is one particular example of this phenomenon , since a reduction in its availability causes a reduction in the recovery after neurotrauma or an ischemic insult .
apoe fragments are produced by trauma - induced proteolytic cleavage , which , in turn , might disrupt the cytoskeleton by the phosphorylation of tau and the promotion of neurofibrillary tangles . at the same time
, apoe4 increases the inflammatory effect of neurotrauma by a significant increase of il-6 , tnf , and no in the injured tissue [ 67 , 68 ] .
microvascular disruption , ionic imbalance , increased intracellular calcium levels , glutamate excitotoxicity , mitochondrial dysfunction , arachidonic acid breakdown , and the activation of inos contribute to the formation of free radicals ( fr ) .
fr are reactive molecules produced by the metabolism of the cell that possess an unpaired electron , which easily reacts with biomolecules by oxidizing them . a fr is made up of sulphur ( s ) , nitrogen ( n ) , chloride ( cl ) , or carbon ( c ) .
metals such as fe , mn , co , ni , and cu can also be considered fr since they have unpaired electrons [ 71 , 72 ] .
many of these molecules are either reactive oxygen species ( ros ) such as delta and sigma oxygen ( o2 ) , superoxide anion ( o2 ) , hydroxyl anion ( oh ) , hydrogen peroxide ( h2o2 ) , or reactive nitrogen species [ ( rns ) no ] . the mechanical reduction of the superoxide anion mediated by nad(p)h oxidases causes the anion to react with no and form a neurotoxic compound known as peroxynitrite ( o2 + no = onoo ) . at physiologic ph , peroxynitrite first reacts with proteins and phospholipids and then breaks down into other cytotoxic products such as no , nitrogen dioxide ( no2 ) , and oh radicals .
hall and braughler demonstrated the occurrence of early posttraumatic lipid peroxidation ( lp ) as early as 5 min after injury .
lp is a mechanism that disrupts the normal structure and function of the lipid bilayers that surround the cell and membrane - bound organelles .
when peroxynitrite or other fr takes an electron off a polyunsaturated lipid , it generates a lipid radical ( l ) that can further interact with molecular oxygen and yield a lipid peroxyl radical ( loo ) .
then , if the resulting lipid peroxyl radical loo is not reduced by antioxidants , lp associated with sci induces early damage to the spinal microvascular endothelium ( within 2 - 3 h ) . as a direct consequence of this damage ,
there are crater formation , platelet adherence , leucocyte presence , and the formation of microemboli , events that are concurrent with the reduced blood flow to the white matter of the spinal cord .
the damage to the myelin sheath unhinged a demyelination process that is the particularity of a neurodegenerative process .
the cns is particularly sensitive to lp because of its high content of peroxidation - susceptible lipids ( arachidonic , linoleic , and docosahexaenoic acid ) and the primarily radical - mediated oxidative protein damage . considering the timeframe of the injury , the oxidative damage to dna and lipids , in addition to protein nitration ,
one of the degradation products of peroxynitrite , no , alters the mitochondrial electron transport chain and induces the production of fr .
these molecules have direct deleterious effect on enzymes with iron - sulfur clusters in their catalytic core , such as ubiquinone succinate .
after sci , the concentration of no increases 3 to 5 times more than baseline levels and reaches its peak at 12 h. meanwhile , there is an increased production of inducible nitric oxide synthase ( inos ) and peroxynitrite .
the resulting elevated no concentration induces cell damage and lipid peroxidation , increases vascular permeability , and causes edema .
hence , due to its involvement in the previous processes , no participates in the development of the excessive glutamate and calcium concentrations that induce excitotoxicity .
however , only inos is capable of producing a high concentration of no for a prolonged period of time .
collectively , astrocytes , neutrophils , monocytes , and microglia induce the expression of inos at the presence of proinflammatory stimuli such as lipopolysaccharide ( lps ) , ultraviolet radiation ( uv ) , and tnf , il-6 , il-1 , and ifn . in some studies
, the expressions of inos and its protein activity were found 3 h , 4 h , 24 h , and 72 h after sci [ 83 , 88 , 89 ] .
the inflammatory response is a characteristic phenomenon of innate immunity that does not require a previous exposition to the agent but does increase substantially with subsequent expositions as the response becomes specific and direct .
cellular immunity consists of specialized cells that can recognize , endocyte , and eliminate different types of microorganisms or noxious substances . on the other hand , the humoral response
is composed by soluble macromolecules that circulate in the blood and extracellular liquid that acts upon the pathogen [ 90 , 91 ] .
sci presents different patterns of gene expression depending on the cell type and activation phase .
numerous studies have suggested that the inflammatory response in sci is beneficial , because it can eliminate tissue debris and induce the release of various neurotrophic factors [ 17 , 93 , 94 ] .
nevertheless , this inflammatory response tends to go out of control when it exacerbates autoreactive mechanisms that cause neural destruction .
traumatic sci triggers inflammatory reactions in which various types of cells , cytokines , and neuroprotective / neuroregenerative molecules are involved . immediately after the rupture of the blood - spinal cord barrier
, the consequent inflammatory response involves the participation of chemical mediators , and resident ( astrocytes and microglia ) and peripheral ( macrophages , lymphocytes ) immune cells [ 96 , 97 ] .
additionally , oligodendrocytes , neurons , and endothelial cells participate in the cellular response after sci , in which microglia and endothelial cells function as antigen - presenting cells ( apc ) . throughout the inflammatory response , the infiltration of immune cells is the principal contributor to neural degeneration .
these cells are guided to the lesion site from the periphery by the effect of chemokines and cytokines that are mainly released by microglia , astrocytes , and peripheral macrophages , which make up the principal resource of these molecules in the lesion site [ 5 , 99102 ] .
the released cytokines include il-1 , il-1 , il-6 , tnf , gm - csf , and lif .
the neurons of human patients expressed these molecules , 30 min after sci , and microglia , 5 h after the lesion ; however , the expression decreased by the 2nd day .
similar results were obtained in mice and rats since the expression by local neurons was found at 1 h , and at 6 h by microglia , which decreased to baseline on day 1 after sci .
the expression of tnf and il-1 by microglia and astrocytes was identified 515 min after the lesion .
the peak expression was at 1 h for tnf and 12 h for il-1 .
the first wave consists of polymorphonuclear leukocytes ( pmn ) that predominate throughout the first hours following the lesion .
they are activated by il-1 , interleukin-2 ( il-2 ) , and il-6 in particular and might be mainly recruited by chemokine ( c - c motif ) ligand 2 ( ccl2 ) , chemokine ( c - x - c motif ) ligand 1 ( cxcl1 ) , and chemokine ( c - x - c motif ) ligand 2 ( cxcl2 , also called macrophage inflammatory protein 2-alpha ( mip2-alpha ) ) .
these cells become apparent in the walls of veins and venules adjacent to the lesion in the first 3 - 4 h and can be observed inside the tissue 824 h after the lesion .
it has been found that these cells represent 90% of the infiltrating cells 12 h after the injury .
the inflammatory response is evidenced by the increased quantity of leukocytes in the cerebrospinal fluid , the infiltration of pmn in the lesion site , the increment in the leukotriene levels ( ltb4 in particular ) , and the activity of myeloperoxidase .
in addition , a significant increase in the expression of intercellular adhesion molecule 1 ( icam-1 ) can be identified , which favors the infiltration of neutrophils from the first 3 to 12 h after the lesion .
the second wave of infiltration is characterized by the presence of monocytes and macrophages , which can be observed around 3 - 4 days after sci .
various chemokines are known to mediate macrophage infiltration such as ccl2 , cxcl1 , and cxcl2 .
this demonstrates how important the recruitment of macrophages is after an injury to the cns [ 109 , 110 ] .
activated microglia become evident in the first day after sci ; moreover , there is a peak in the proliferation and recruitment of microglia from day 3 to day 7 [ 111 , 112 ] .
the overexpression of lif has been found to cause a dramatic increase in the proliferation of microglia / macrophages and astrocyte activation .
the pathological proliferation of macrophages and microglia might contribute to the subsequent exacerbation of the initial damage [ 113 , 114 ] , even though macrophages have an important role in the clearing of denatured dendrites .
microglia at the injury site rapidly express the alarmin il-1 , while infiltrating neutrophils and macrophages produce il-1 which plays a role in the infiltrating mechanism of these cells .
interestingly , the expression of il-1 mediates the suppression of the survival factor tox3 ( tox high mobility group box family member 3 ) in oligodendrocytes , which in the absence of such cytokine would provide protection of this cell population , and functional recovery after sci .
diverse studies have reported that the recruitment of leukocytes to the injured spinal cord is a physiological response that is associated with the production of cytokines and protein kinases that are involved in the repair of the site of lesion .
neutrophils , for example , are the first cells to be recruited with the objective of clearing the lesion site from possible pathogens and cellular debris through phagocytosis .
however , the activation of these cells also induces the release of a significant amount of neurotoxins such as ros , rns , chemokines , and a variety of enzymes that promote tissular destruction [ 105 , 116 , 117 ] .
the taoka report provides evidence demonstrating that after sci the maximum peak of neutrophil migration perfectly correlates with the extent of the damage and the motor alterations observed after the lesion .
the infiltration of monocytes and macrophages after sci has for its objective the removal of cellular debris and the stimulation of new blood vessel and parenchymal cell formation .
the infiltration of these cells regulates the activation and proliferation of t lymphocytes since they play the role of apc .
microglia are pluripotent cells capable of developing different phenotypes proportional to the severity of the lesion , which determines the intensity of the inflammatory response , the quantity of recruited cells , and the magnitude of the immunological response .
this can be explained by the interaction between microglia and t lymphocytes , since it induces an antigen specificity that regulates the immune response and the subsequent phases .
microglial cells are distributed throughout the cns , where they serve as a pathological sensor that is activated in response to noxious stimuli such as physical trauma or vascular obstruction . activated microglia migrate to the site of injury ,
proliferate , and transform from the resting phenotype ( ramified cells ) to amoeboid phagocytic cells .
in fact , after sci , activated microglia can be seen at the epicenter of the lesion initially at 12 h .
in addition , there is an upregulation of surface receptors such as cr3 ( complement receptor type 3 ) and mhc ii ( major histocompatibility complex ) whose implications are covered in several papers of our group .
these activated microglia can then release a series of cytokines , chemokines , and enzymes , which are proportional to the activating stimulus as mentioned previously .
the series encompass il-1 , il-6 , tnf , tgf-1 ( transformation growth factor-1 ) , m - csf , inos , ngf ( neural growth factor ) , nt-3 ( neurotrophin-3 ) , and bndf ( brain neuronal derived factor ) [ 122 , 123 ] .
interestingly , monocyte derived microglia and macrophages might be able to induce regeneration by the secretion of neurotrophic factors , particularly tgf-1 .
activated microglia and macrophages have been implicated in the secondary pathology that accompanies traumatic or autoimmune injuries to the brain and spinal cord .
the associated implications usually refer to the activation of these cells towards an inflammatory m1 phenotype ; however , these cells can also be activated towards an m2 macrophage phenotype that responds to il-4 and il-13 .
this contrasting phenotype is characterized by the production of several extracellular matrix proteins that may promote tissue remodeling , repair , neurotrophic support , and axonal regeneration [ 125128 ] .
taking into account the excessive release of glutamate and the feedback of the inflammatory response after sci , it is no surprise that microglia acquire a reactive phenotype that expresses very low quantities of the mhc ii molecules and is not capable of maintaining an adequate interaction with t lymphocytes [ 118 , 129 ] .
the m1 phenotype is characterized by the excessive release of no , il-1 , il-6 , and tnf , which leads to toxicity . in these conditions ,
astrocytes and postsynaptic neurons show signs of damage , evidenced by the expression of ros , which can induce apoptosis . nevertheless , activated microglia remove the cellular debris after the lesion and are capable of promoting revascularization in the site of injury , which facilitates the release of trophic factors and nutrients for the survival and proliferation of infiltrating cells in the lesion site .
furthermore , microglia are capable of expressing glutamate transporters , which apparently help buffer the excessive concentrations of glutamate , and consequently protect cells from toxicity [ 129 , 130 ] .
it is important to take the before - mentioned into account since activated microglia and peripheral macrophages make up the majority of inflammatory cells present in the site of lesion , especially since these cells are morphologically different and respond to different modulatory signals in an early response of the innate immunity to the lesions of the cns , which have diverse etiologies such as ischemia and neurotrauma [ 132 , 133 ] .
therefore , given that in the brain and the spinal cord there is a considerable heterogeneity of macrophages , the relative contribution of one population of cells in the local inflammatory reaction can dictate whether a cascade of events initiates as a regenerative or a destructive process .
this all depends on the macrophage phenotype activated , particularly microglia . in regard to t - lymphocyte infiltration in humans
, it might be detected months after the injury , and b - lymphocytes are not usually found . on the other hand ,
mice models present both cell types 7 days after sci , with a peak at 42 days .
traditionally , their participation after sci has been linked with the damage to neural tissue since they are capable of producing proinflammatory cytokines such as inf and il-1. on one hand , inf is linked directly to neuronal destruction since it induces the expression of other proinflammatory cytokines ( tnf , il-6 , il-12 , and il-1 ) , and proinflammatory molecules such as ros and inos , since it participates in the induction of transcription factors including nf ( nuclear factor kappa beta ) and ap-1 ( activator protein-1 ) [ 118 , 136 , 137 ] .
in addition , inf is known to participate in the induction of a cytolytic response by tcd8 + ( cd , cluster of differentiation ) since it is the principal inductor of mhci through the phosphorylation of stat1 ( signal transducers and activators of transcription-1 ) . moreover , the chemoattractant , c - x - c motif chemokine 10 ( cxcl10 ) recruits cd4 th1 cells via the cxcr3a receptor .
after the induction of protective autoreactivity , which is a strategy based on the modulation of the immune response by neural derived peptides , diverse studies have reported that the presence of t lymphocytes with a th2 phenotype in the lesion site favors functional recovery [ 139141 ] .
this is due to their ability to synthesize ngf , bdnf , and diverse neurotrophins ( nt3 , nt4 , and nt5 ) [ 142 , 143 ] . in a classical th1 activation pattern ,
however , the inflammatory response after sci can be responsible for the necrosis of the lesion site and the surrounding area [ 144146 ] . to further explore this phenomenon
the cytokine expression was analyzed in comparison to sham animals and the dominant phenotype was found to be th1 and th17 predominantly according to expectations [ 147 , 148 ] .
this is due to its important role in the generation of free radicals , cytokines , and chemokines that exacerbate the damage to the neural tissue for weeks or even months .
it is important to point out that this noxious effect occurs when the immune response is not modulated , since it is correlated with excitotoxicity , lipid peroxidation , and the development of an autoreactive response towards neural constituents [ 17 , 93 , 139 , 149 , 150 ] .
contrastingly , this response can either increase the damage to the neural tissue , promote protection [ 150153 ] , or even promote restoration of the injured tissue [ 126 , 127 , 144 ] as a function of neuromodulation .
the autoreactivity observed after sci is characterized by the specific immune response , with lymphocytes being the only cells capable of specifically recognizing the antigens , and initiating the adaptive immune response . despite the existence of mechanisms by which these autoreactive t cells are eliminated or inactivated , these are not sufficient , and consequently they can be found in practically every healthy individual .
thus , autoreactivity can be part of a normal immune response that can find its origin in several infectious and inflammatory diseases .
however , when this mechanism is excessive , the result is an autoimmune disease [ 154156 ] .
there are multiple diseases that are considered to be autoimmune or to have an autoimmune component .
it is an inflammatory , demyelinating disease , in which an autoimmune response to mbp has been reported .
interestingly , after sci , an autoreactive phenomenon similar to the pathophysiology of ms can be observed .
consequently , it is well - known that the lymphocyte role after sci is fundamental , because these cells are responsible for the generation of autoimmunity in individuals with genetic susceptibility [ 89 , 158 , 159 ] .
if not regulated , the response would involve the participation of other immune cells , other signaling pathways , and other patterns of gene expression .
the persistent influx of immune cells from the systemic circulation as neutrophils , macrophages , lymphocytes , basophils , and eosinophils is correlated with additional elevation of proinflammatory cytokine levels and neural tissue destruction that would unavoidably make tissue recovery more difficult [ 108 , 160 , 161 ] .
cytokines comprise a large family of small signaling proteins that affect nearly every biological process including embryonic development , disease , nonspecific infection response , cognitive functions , aging , cellular growth , survival , and differentiation [ 10 , 162 ] .
these cytokines , which can be classified as peptides , proteins , or glycoproteins , encompass interferons , interleukins , the chemokine family , the tumor necrosis factor family , adipokines , and mesenchymal growth factors [ 10 , 163 ] .
these molecules are produced by one cell and go on to act on another cell in order to bring a change in the function of the target cell .
the difference with hormones is that cytokines are products of most cells while not being of a particular tissue or cell .
the majority of cytokines function by binding to specific cell surface receptors ; this action triggers intracellular signaling and activates transcription factors such as ap-1 and nf .
interestingly , the diverse properties of a single cytokine can be explained by the following mechanisms : the first mechanism involves the presence of the receptor of a certain cytokine in one particular type of cell ( e.g. , il-33 receptor on mast cells ) .
the second mechanism is explained by the presence of the receptor to a specific cytokine on most cells ( e.g. , activation of nf by il-1 , or tnf induction of cox-2 ) .
the third mechanism encompasses the ability of cytokines to induce or function as coactivators ( e.g. , il-18 induces ifn when il-12 is present , but when it is not , il-18 induces fas ligand ) . despite the fact that cytokines are studied in every discipline of biology , the effects of these molecules are mostly studied in the realm of inflammation , immunology , cancer , and atherosclerosis . in these areas , cytokines can be grouped into a proinflammatory or anti - inflammatory category on the basis of the resulting balance of their added effects . in the cns ,
surprisingly , they also have the capability of contributing to neuronal damage and destruction when their concentration exceeds a certain threshold .
one of the reasons as to why they cause such damage and destruction lies in the uncontrolled inflammatory response observed after sci , which emphasizes the reason behind the augmented study of these molecules in inflammation - related research .
the upregulation of these cytokines , as well as the consequent cellular infiltration they cause , plays a crucial role in the determination of the extent of the secondary tissue damage and neural degeneration observed after the injury [ 95 , 166 , 167 ] . therefore , taking into account that the production and release of proinflammatory cytokines and chemokines ( table 1 ) is the first inflammatory event that develops after sci , the importance of these molecules becomes clear [ 166 , 167 ] . in regard to the realm of inflammatory cytokines , there is a clear diversity in their functions . for starters , certain molecules are capable of inducing vascular permeability and cellular fluid loss , which include components of the complement cascade ( c3a and c5a ) , which in turn cause the release of histamine , prostaglandins , and leukotrienes from resident mast cells .
specific inflammatory cytokines such as tnf , il-1 , and il-6 are synthetized by various cells in the cns and are known as mediators of the peripheral immune response [ 168170 ] .
on one hand , tnf immediately recruits neutrophils to the site of the lesion by the induction of adhesion molecules such as icam-1 and vcam-1 ( vascular cell adhesion molecule-1 ) , as it stimulates the release of il-8 , which is a chemotactic factor for neutrophils .
furthermore , tnf alters the permeability of endothelial cells and damages the blood - spinal cord barrier .
moreover , this cytokine is able to exert cytotoxic activity towards oligodendrocytes and contributes to demyelination .
in addition , tnf also stimulates the proliferation and hypertrophy of astrocytes , hereby promoting the formation of the fibroglial scar , which acts as a barrier to a possible regeneration of the cns as a biological measure of last resort in response to an uncontrolled chronic inflammation [ 168170 ] . on the other hand
, studies have shown that a direct injection of il-1 into the spinal cord leads to enhanced vascular permeability and lymphocyte recruitment .
subsequently , il-6 has been found to promote the activation and infiltration of macrophages and microglia [ 161 , 171 ] .
in fact , it is known that il-6 is a major player in chemokine infiltration , because it has the ability to interact with other cytokines and neurotrophic factors [ 172 , 173 ] .
interestingly , several studies have revealed that the continuous inhibition of il-6 is detrimental to functional recovery because it also participates in axonal regeneration and gliosis , in line with the role of tnf in chronic inflammation [ 174 , 175 ] .
thus , it is important to take into account that the mediation of the early inflammatory tissue damage may actually worsen the functional outcome .
this leads to a conflict , since the role of inflammation after sci appears to be contradictory when the before - mentioned and following points are taken into account . on one hand ,
proinflammatory cytokines , il-1 and il-6 , are beneficial at low concentrations due to their induction of neurotrophin expression and the mediation of leukocyte activation / recruitment to the injury site by the induction of adhesion molecules in the cell surface such as icam-1 , p - selectin , and e - selectin [ 172 , 173 ] . on the other hand , at higher concentrations , these inflammatory cytokines activate transcription factors such as nf , ap1 , and atf , factors that stimulate the expression of neurotoxic genes , including cox-2 , inos , and proinflammatory proteases in different target cells [ 88 , 178 , 179 ] .
pan found that the mrnas of cytokines such as tnf , il-1 , il-1 , and il-6 could be detected 15 min after injury . from these cytokines ,
il-1 and il-1 continually reached peak levels until the 6 h but were not present from the 12 to 24 h after sci .
in addition , by 4 h after contusive sci , significantly increased mrna levels of il-1a and il-6 were clearly detected by qrt - pcr [ 180 , 181 ] . digging further into the time frame of expression , western blot studies found that the mature form of il-1 is expressed by the 2 h. this evidence suggests that the inflammatory cytokine is released very quickly after tissue damage .
the expression of these genes was identified 1 h after contusive rat sci by cdna microarrays .
the procedure was then repeated in spinal cord injury patients , and the same results were observed .
moreover , hayashi found that after sci the mrnas of cytokines such as tnf and il-1 were upregulated in as little as 13 h after the lesion [ 148 , 182 , 183 ] . on another note ,
tnf mrna peaked quickly 60 min after the injury and fell slightly by the 120 min .
tnf mrna remained elevated by day 1 after sci , returned to a low level by day 3 , and was not detected by day 5 .
il-6 mrna increased slowly , reached peak levels by 612 h , and fell by 24 h .
it is important to note that the levels of these mrnas were nearly undetectable in sham - injured animals .
another study found that , between 12 h and 72 h after sci , the gene expression of proinflammatory cytokines such as il-1 , il-3 , il-6 , and their receptors was strongly upregulated .
consequently , the downregulation of the signaling of il-1 and tnf reduces the induction of il-1 mrna .
this suggests that the activity of these cytokines contributes to their own mrna regulation [ 163 , 180 ] . from the 3 h and up to 24 h , tnf , il-1 , il-6 , and lif
it is worth noting that another wave of expression was observed for tnf and il-1 at 14 days , which correlates with an increased blood - spinal cord barrier function . in particular ,
the overexpression of lif has been found to cause a dramatic increase in the proliferation of microglia / macrophages and astrocytic activation .
tnf is released significantly faster than other proinflammatory cytokines , because this is stored in a preformed state on the cell surface and in the granules of mast cells .
it is not a surprise that role of this cytokine is similar to that of il-1 given the facts stated above .
it is important to note that tnf is the principal promoter of wallerian degeneration since it activates resident schwann cells in the peripheral nervous system and facilitates macrophage recruitment into the injury site .
similar to the facts stated above , the extracellular expression of tnf in the surrounding white matter was detected 3 h posterior to contusion sci , with a peak that took place from day 1 to day 3 .
the following information regards the receptors of such molecular products . from the two subtypes of tnf receptor that exist
, each subtype has a different distribution and presence that depends on the particular cell type .
tnf - r1 is expressed constitutively on most cell types , whereas the expression of tnf - r2 in astrocytes requires induction by tnf , il-1 , and ifn .
a large amount of evidence indicates that tnf - r1 augments neuronal death and tnf - r2 promotes neuroprotection . what has been observed in the lesion
concludes that the expression of tnf - r1 and tnf - r2 is increased within 15 min after traumatic sci in adult rats and reaches its peak at 4 h for tnf - r2 and 8 h for tnf - r1 .
the expression of both receptor subtypes then goes on to decline after day 1 and day 3 , respectively .
it is important to note that these receptors are initially found on the epicenter of the lesion site .
posteriorly , they spread radially towards distant areas during their peak expression and later become confined to the lesion area .
these receptors are expressed by several cells , which include neurons , oligodendrocytes , and astrocytes [ 189 , 190 ] .
these cells might work individually or synergistically to mediate the biological activity of tnf , which makes an interesting research topic , given that these receptors are known to be involved in antiapoptotic activities through the tnf - r / nf signal transduction pathway . on a last note , tnf participation in the expression of inos in microglial cells causes an exacerbated neural destruction as a direct consequence of the induction of the nf pathway , which can then contribute to the expression of ifn. ifn within the nervous system is classically associated with the inflammatory response after injury as mentioned in the previous paragraph .
this molecule is believed to be normally involved as one component of the physiological response to tissue damage and trauma .
cd4 + and cd8 + t cells together with natural killer ( nk ) cells are the major sources of ifn. nevertheless , evidence shows that this cytokine is also produced within the nervous system by neurons and glial cells in the absence of infiltrating immune cells . in various animal models ,
ifn promotes macrophage signaling , production of proinflammatory cytokines and chemokines , recruitment of macrophages to the cns , and the activation of cns resident and infiltrating apc populations . moreover , ifn is also the most potent inductor of mhci , and it is upregulated in the cns after injury . in low concentrations ,
ifn may participate in the homeostasis of the synaptic circuitry [ 216 , 217 ] .
as previously mentioned , ifn is involved in the upregulation of mhc i , which has been shown to play an important role in the synaptic plasticity process following axotomy .
furthermore , ifn has been shown to regulate phosphorylation and nuclear translocation of signal transducer and activator of transcription 1 ( stat1 ) and to influence neuronal excitability by the expression of the peripheral nerve - type sodium channel gene pn1 .
it is important to note that several studies found that ifn and il-17 had the highest levels of gene expression , since this indicates that the phenotype found after sci is predominantly th1 and th17 and the ifn release could be detected from 1 h to 12 weeks , depending on microenvironment [ 147 , 148 ] .
interleukin-17 ( il-17 ) is primarily produced by th17 cells and has an important role in inflammation and autoimmune disease . a key regulator in its production
. nevertheless , tgf- and interleukin-21 ( il-21 ) are also capable of stimulating il-17 production .
similarly , interleukin-23 ( il-23 ) is also able to promote il-17 production just as interleukin-22 ( il-22 ) does . in one study ,
serum levels of il-6 , il-21 , and il-23 were increased in large quantities 1 h after sci , had a peak at 24 h , and had a positive correlation with increased il-17 .
signal transducer and activator of transcription 3 ( stat3 ) and rar - related orphan receptor gamma ( ror ) are two transcription factors capable of mediating il-17 production and th17 differentiation . as a result ,
a closed circuit is formed , in which il-17 , the stat3 signaling pathway , and il-17 related cytokines promote neuroinflammation as they costimulate one another .
il-17 expression and production was detected from 1 h to 72 h after contusion injury .
the phosphorylation of stat3 in this pathway induces a proinflammatory gene expression that correlates with il-17 quantities in spinal cord neurons and astrocytes .
interestingly , through this very same pathway , anti - inflammatory th2 cells can be suppressed by il-6 inhibition of foxp3 expression in a stat3 dependant manner .
it is important to recognize that stat3 was found higher in the sci rat group , whose expression peaked at 24 h .
it is worth noting that il-17 antagonistic therapy in rheumatoid arthritis ( ra ) suggests that the inhibition of the pathological role of il-17 may be a promising therapeutic approach in humans .
chemokines are grouped into two families : the family ( cxc ) , which participates in the recruitment of polymorphonuclear cells , and the family ( c - c ) , which provides the priming signal for macrophages , lymphocytes , eosinophils , and basophils .
the family includes gamma - interferon inducible protein ( ip-10/cxcl10 ) , platelet factor 4 , il-1 , and melanoma growth stimulatory activity ( mgsa / gro / kc ) . in particular ,
the chemokine cxcl10 has been shown to inhibit angiogenesis , growth , and chemotaxis of endothelial cells via the cxcr3b receptor .
consequently , the neutralization of cxcl10 promotes angiogenesis through the expression of eight genes related to angiogenesis and vasculature remodeling after sci .
an important member of the family is the monocyte chemoattractant protein ( mcp-1/ccl2 ) .
it is detected in astrocytes and perivascular mononuclear cells in experimental allergic encephalomyelitis ( eae ) .
mcp-1 levels are related to the parallel development of clinical disease and macrophage infiltration [ 205 , 206 ] .
the same case applies to macrophage inflammatory protein 1 alpha ( mip-1/ccl4 ) and macrophage inflammatory protein 1 beta ( mip-1 ) .
their expression has been shown predominantly in myeloid and lymphoid cells , where an increased expression of mip-1 , mip-2 ( cxcl2/3 ) , and mcp-1 after sci plays a role in the inflammatory process , since these molecules recruit circulating leukocytes to the injury site .
mcp-1 mrna was present in the normal spinal cord , was increased 1 h after sci , peaked at 24 h , and returned to a low level by day 14 .
in addition , mip-1 mrna was present in the normal spinal cord , where it increased at 1 h after sci , peaked from 3 to 6 h , decreased by day 1 , remained unchanged until day 7 , and returned to a low level by day 14 .
additionally , the expression of this molecule was found at the contusion site and in rostral and caudal sections to this location . by day 5 after injury ,
moreover , ip-10 mrna presented low levels in the normal spinal cord , increased its levels at 1 h , peaked at 6 h , and remained high up to day 5 after sci .
another study found the chemokines , mcp-1 , mip-1 , mip-1 , mip-2 , and ip-10 , to be expressed locally at 30 min with a peak at 6 h after sci .
it is worth noting then that chemokines remain present 24 d after injury at lower levels in contrast with the rest of the cytokines .
the changes in gene expression that contribute to the secondary injury are characterized by protracted neuronal loss and neurological dysfunction .
therefore , the predominant downregulation of these factors might play a role in cell survival and may lead to the development of novel interventions that promote recovery [ 181 , 221 , 222 ] . in order to develop a viable therapy , it is essential to identify the specific molecular pathways that become altered as a function of time after sci .
for instance , activated macrophages and microglia after cns injury produce various neurotrophic factors and molecules that enhance regeneration [ 93 , 224 ] . however , this response highly depends on the temporal sequence that proceeds the injury .
this consequently indicates that there is a proper and timely regulation of inflammatory reactions that can take place and be of paramount importance to the design of therapeutic strategies involving cytokines , growth factors , or neurotrophins [ 98 , 116 ] .
for instance , endogenous il-4 has been shown to participate in the regulation of neuroinflammation in various pathologic conditions [ 196198 ] .
this anti - inflammatory cytokine and its receptor subunit il-4 have a role in spinal cord trauma .
this is illustrated by the high level expression of il-4 24 h after contusive sci in rats , whose elevated concentration persisted for 7 days but was decreased 3 days after sci .
interestingly , on day 1 after sci , an increased expression of il-13 was observed .
this is noteworthy since this interleukin shares the same receptor with il-4 for signal transduction [ 166 , 199 ] .
moreover , the cytokine expression of the contused spinal cord was not significantly affected by il-4 attenuation for the proinflammatory cytokine levels of il-1 , il-6 , and tnf. in fact , the opposite effect was observed , since the event correlated with a marked increase in the extent of macrophage quantity 7 days after sci , which was preceded by an increase in the level of mcp-1 .
these results suggest that the expression of il-4 regulates the extent of macrophage activation in the acute phase of the injury .
in addition , il-4 has been shown to exert a neuroprotective effect against microglia - mediated neuronal toxicity by the regulation of fr formation .
on similar lines , macrophages stimulated with il-4 are reported to be less neurotoxic and to have an increased regenerative capability .
il-10 and tgf have been reported to act as neuroprotective molecules in a manner similar to il-4 .
for instance , it has been shown that an intrathecal infusion of tgf is able to enhance axonal growth after spinal contusion through the epidermal growth factor receptor ( egfr ) that is primarily upregulated by astrocytes surrounding the lesion . here
, tgf stimulates proliferation , migration , and transformation to an axon phenotype supportive of growth . on the other hand ,
a potential treatment for certain aspects of the secondary injury such as inflammation , excitotoxic damage , and neuronal apoptosis is the administration of il-10 since its anti - inflammatory effects involve the downregulation of il-1 , il-2 , il-6 , tnf , ifn , matrix metalloproteinase-9 , nitric oxide synthase , myeloperoxidase , and ros .
in addition , proapoptotic factors such as cytochrome c , bax , and caspase 3 are downregulated by the effects of il-10 .
other effects of this cytokine include the upregulation of antiapoptotic factors such as b - cell lymphoma 2 ( bcl-2 ) .
furthermore , il-10 provides trophic support to neurons by its receptor , in addition to increased tissue sparing , neuroprotection , and functional recovery . in the nervous system ,
il-10 receptor expression has been found in microglia , astrocytes , and oligodendrocytes acting as antagonist for the production of proinflammatory cytokines [ 225 , 227 ] . in the first moments after sci , the elevated synthesis and release of proinflammatory mediators plays a role in the secondary degeneration .
for instance , an antagonist of proinflammatory cytokines such as il-1 receptor antagonist has demonstrated a neuroprotective effect after global ischemia , excitotoxicity , and traumatic brain injury in rodents .
( 2 ) growth factors . after mechanical trauma , astrocytes and neurons release fibroblast growth factor ( fgf ) which is thought to counteract excitotoxic or ischemic damage by the activation of antiapoptotic signals in stressed neurons .
acidic fibroblast growth factor ( afgf ) is a potent mitogenic and chemotactic agent for vascular endothelial cells , dermal fibroblasts , and epidermal keratinocytes .
moreover , it has a role in the regeneration process since it contributes to angiogenesis . in the normal uninjured spinal cord
after sci ( table 2 ) , however , the factor increased in the 1 h , stayed at that level , peaked from day 5 to day 7 , and remained high from day 14 to day 21 .
a particular strategy that has shown significant results is the combination of peripheral nerve grafts with afgf after transection sci in rats .
this strategy induced higher il-4 , il-10 , and il-13 levels in the graft areas of rat spinal cords .
moreover , this strategy has been shown to regulate th2 cytokine production , m2 response , and neurotrophic factor production , where the latter can indirectly regulate the inflammatory response and neural destruction .
it is worth noting that the use of afgf with fibrin glue in combination with surgical neurolysis for nonacute sci has been proven feasible and safe in clinical trials which have shown significant improvements in asia motor and sensory scale scores and impairment scales , neurological levels , and functional independence measures , 24 months after treatment .
after the injury , the expression of basic fibroblast growth factor ( bfgf ) , another growth factor involved in angiogenesis , was found in astrocytes localized at the site of contusion and in the surrounding white matter . unlike afgf
it was only detected 1 h after sci , in increased quantities at 6 h , and at its peak 3 days after sci .
afterwards , it remained high from day 5 to day 7 , only to return to a low level by days 14 to 21 . before going further ,
it is important to note that growth factors such as tgf- may act as immunosuppressants . moving on , 24 h after sci , genes related to growth and differentiation became present .
these included tgf- , nerve growth factor ( vgf ) , platelet derived growth factor ( pdgf- ) , galanin , and neuropeptide y. these genes have been suggested as aids in tissue stabilization , structural preservation , repair , and regeneration after sci .
for instance , increased pdgf and vgf levels after sci may prevent the death of axotomized neurons and a decrease in their energy metabolism .
subsequently , the increased abundance of galanin and neuropeptide - y transcripts may produce an antinociceptive effect in the injured spinal cord .
moreover , it is known that cannabinoid receptor 1 ( cb1 ) is colocalized with the neuropeptide cck . in this relationship
therefore , the downregulation of cb1 and the expression of the cck precursor might help explain why there is a relative resistance of neuropathic pain to the analgesic action of morphine in sci patients .
similar results have been found in several transcripts , and the previously mentioned genes have shown an increased abundance in comparison to sham animals [ 57 , 223 , 234 ] .
neurotrophins constitute a family of molecules that has assumed a central role in studies dealing with recovery after sci .
four members of this family are involved in neuron survival and the regeneration process after sci : ngf , brain derived neurotrophic factor ( bdnf ) , neurotrophin-3 ( nt-3 ) , and nt-4/5 .
neurotrophins emit signals when they bind to low and high affinity receptors in the membrane of their target cells .
another signaling method used by neurotrophins is carried out by three high affinity tyrosine kinase receptors , collectively known as trk receptors .
trka , trkb , and trkc compose the trk family of tyrosine - protein kinases .
trka is the particular receptor for ngf , while trkb serves as a receptor for both bdnf and nt-4 .
however , this particular neurotrophin can activate trka and trkb receptors when present in high concentrations . through semiquantitative rt - pcr in a spinal cord contusion model
, it was found that the expression of neurotrophin family members and their receptors was significantly diminished 6 h after the lesion . yet , in contrast to this pattern of trk receptor expression , p75ntr showed a significant upregulation after contusive sci .
interestingly , an increase in bndf was observed up to 6 weeks after compression sci with a decrease 12 weeks afterwards .
similarly , an increased expression of growth , angiogenic , and axonal guidance factors , as well as extracellular matrix molecules , can be observed in the chronic phase ( days to years ) following sci [ 150 , 209 ] .
the series of interconnected deleterious mechanisms of the secondary injury is orchestrated by the expression of specific genes , in particular those of signaling proteins such as cytokines , chemokines , and growth factors .
the balance between the proinflammatory and anti - inflammatory effects of these molecules plays an important role in the progression and outcome of the degenerative process .
most of these cytokines have a dual role in a range between beneficial and injurious , depending on time and the cell implicated in secondary injury after sci .
the excessive and uncontrolled inflammatory response after sci enhances the damage role of these cytokines , which surpasses the regenerative effects of anti - inflammatory cytokines and growth factor .
consequently , therapies that focus on promoting the anti - inflammatory properties of cytokines and growth factors should be a priority . | ### Summary:
: spinal cord injury results in a life - disrupting series of deleterious interconnected mechanisms encompassed by the primary and secondary injury .
these events are mediated by the upregulation of genes with roles in inflammation , transcription , and signaling proteins . in particular
, cytokines and growth factors are signaling proteins that have important roles in the pathophysiology of sci .
the balance between the proinflammatory and anti - inflammatory effects of these molecules plays a critical role in the progression and outcome of the lesion .
the excessive inflammatory th1 and th17 phenotypes observed after sci tilt the scale towards a proinflammatory environment , which exacerbates the deleterious mechanisms present after the injury .
these mechanisms include the disruption of the spinal cord blood barrier , edema and ion imbalance , in particular intracellular calcium and sodium concentrations , glutamate excitotoxicity , free radicals , and the inflammatory response contributing to the neurodegenerative process which is characterized by demyelination and apoptosis of neuronal tissue . |
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: restoration of neutral mechanical alignment of the lower limb in total knee arthroplasty ( tka ) has been demonstrated as a key determinant of the longevity of knee implants in various studies1,2 ) . in a neutrally aligned limb ,
the mechanical axis passes through the center of the knee joint , thereby minimizing the risk of component wear and loosening3,4,5 ) .
however , the importance of neutral mechanical alignment is based on the premise that the mechanical axis passes through the center of the knee joint , the medial proximal tibial angle ( mpta ) is 3 , and the femoral anatomic mechanical angle ( fama ) is 6 in the normal knee .
furthermore , recent studies have shown that a great extent of medial soft tissue release is required for restoration of neutral mechanical alignment in patients with constitutional varus knees ( 3 varus alignment ) and such patients are more common than previously thought , specifically 32% in males and 17.2% in females in a western population6 ) . in this study , we investigated whether the lower limb alignment was neutral in healthy korean females without symptoms of knee osteoarthritis and assessed the incidence of constitutional varus knees among them .
this study was conducted with our institutional review board approval on 121 female volunteers between the ages of 20 to 39 years who had been working at our hospital .
informed consent was obtained from all volunteers prior to study and knee joint pain and history of trauma were defined as exclusion criteria .
three of the volunteers were excluded due to femoral head deformity , rotational deformity of the femur , and congenital tibial deformity .
their mean age was 26.76 years and the mean body mass index ( bmi ) of 21.62 kg / m was within the normal range ( table 1 ) .
weight - bearing full - leg standing radiographs were taken with the patients standing barefoot . to preclude errors due to rotation
, the medial borders of the heels and the first metatarsophalangeal joints of both foot were positioned to be in full contact , with the patella facing forward .
the distance between the source of radiation and the patient was 300 cm . with three 1717 inch cassettes placed behind the hips , knees , and the feet ,
radiographs were taken at 100 mas , 64 mas , and 32 mas , respectively .
one radiologist and two orthopaedic surgeons independently measured the hip - knee - ankle angle ( hkaa ) , mpta , and fama in each patient for comparison with the gold standard values ( hkaa , 0 ; mpta , 3 varus ; and fama , 6 ) .
the possible causative factors of constitutional varus knees , femoral bowing angle ( fba ) and mechanical lateral distal femoral angle ( mldfa ) were also measured .
the hkaa was defined as the medial angle formed by the axes that pass through the center of the femoral head , the midpoint between the tips of the tibial spines , and the center of the superior facet of the talus .
the angle was assigned a negative value if it was less than 180 ( varus alignment ) whereas a positive value was given if it was greater than 180 ( valgus alignment ) .
the mpta was measured as the medial angle between the mechanical tibial axis and the knee joint line of the proximal tibia .
the angle lesser than 90 represent a varus alignment , and the angle greater than 90 a valgus alignment .
three points were marked on the femoral shaft as follows , the midpoint of the medullary canal at the lower junction of the lesser trochanter ( proximal femoral point ) , the midpoint of the medullary canal 10 cm proximal to the knee joint ( distal femoral point ) , and a point midway between the proximal and the distal femoral points ( middle femoral point ) .
the fama was calculated as the angle formed between the femoral mechanical axis and the femoral anatomical axis which is the line from the proximal femoral point to the distal femoral point .
the fba was determined as the angle between the line from the proximal femoral point to the middle femoral point and the line from middle femoral point to the distal femoral point .
the mldfa was measured as the lateral angle between the femoral mechanical axis and the joint line of the distal femur ( figs .
categorical variables were described as frequency and percentage while continuous variables were expressed as meanstandard deviation ( sd ) .
the icc was calculated using a two - way mixed model with a consistency definition .
a one - sample t - test was used for comparison between the values of the continuous variables and the standard values ( hkaa , 0 ; mpta , 3 varus ; and fama , 6 ) .
, armonk , ny , usa ) and p - value of less than 0.05 was taken as significant .
the iccs for hkaa and mpta were 0.967 and 0.933 , respectively , indicating excellent interobserver reliability .
the iccs for fama , fba , and mldfa were 0.797 , 0.866 , and 0.811 , respectively , showing excellent ( > 0.79 ) interobserver reliability .
thus , the reliability of measurements was statistically significant for all continuous variables ( p<0.001 ) ( table 2 ) .
6 ) , the mean mpta was -3.18 ( sd , 1.61 ) , the mean fama was 5.99 ( sd , 0.70 ) , the mean fba was 1.96 ( sd , 1.53 ) , and the mean mldfa was 87.78 ( sd , 1.68 ) ( table 2 ) .
the one - sample t - test for comparison of the mean hkaa , mpta , and fama values against the standard values ( hkaa , 0 ; mpta , -3 ; and fama , 6 ) showed a statistically significant difference for the hkaa ( p<0.001 ) .
however , no significant difference was observed with regard to the mpta ( p=0.083 ) and the fama ( p=0.887 ) ( table 3 ) .
the hkaa , indicating the overall axis of the lower limb , was within the range of -3 to + 3 in 186 knees ( 78.81% ) , below -3 in 48 knees ( 20.34% ) , and over + 3 in 2 knees ( 0.85% ) .
the incidence of constitutional varus knees with 3 varus alignment was relatively high in the study participants ( 20.34% ) compared to that in western females ( 17.2% ) ( table 4 ) .
with the advent of patient specific implants for tka , the concept of natural anatomic alignment has been growing interest as an alternative to neutral mechanical alignment7,8 ) . in addition , an increasing number of surgeons have begun to question the importance of restoration of neutral mechanical alignment in patients who have had varus alignment since the attainment of skeletal maturity6 ) .
therefore , we investigated whether normal korean females had neutral mechanical alignment ( hkaa , 0 ; mpta , 3 varus ; and fama , 6 ) and the incidence of constitutional varus knees among them .
our results showed that the mpta and fama in the study participants were not significantly different from the standard values .
the fba was in slight valgus ( mean value , 1.96 ) , and the mean mldfa ( 87.78 ) was not significantly different from the other studies .
however , the mean hkaa was slightly in varus deviation ( -1.352.04 ) . that results was different from the known neutral axis of 0 and showed a statistically significant difference ( p<0.001 ) . the presence of slight varus deviation from neutral mechanical alignment has been reported in many studies .
moreland et al.9 ) reported a mean of 1.3 varus alignment in normal western males and hsu et al.10 ) noted a mean of 2.3 varus alignment in western males and 1.3 varus alignment in western females .
tang et al.11 ) reported that a mean of 2.2o varus alignment was observed in a chinese population regardless of gender .
bellemans et al.6 ) documented that constitutional varus alignment ( 3 varus deviation ) was observed in 17.2% of the western female knees . in our study ,
the incidence of constitutional varus alignment ( 20.34% ) was relatively high compared to that in the above mentioned study .
factors associated with constitutional varus alignment including increased femoral varus bowing , an increased varus femoral neck - shaft angle , and an increased femoral anatomic mechanical angle were considered12 ) .
however , shetty et al.13 ) showed that the hkaa was most positively correlated with the mpta in indian and korean adults , whereas there was no significant correlation with bmi , femoral bowing , and femoral neck - shaft angle . according to bellemann et al.6 ) constitutional varus alignment
was associated with increased sports activity during the growth spurt in the teenage years , whereas no significant correlation was established with weight , body type , and bmi . in particular ,
intense sports activity at the end of the growth spurt ( range , 14 to 16 years ) imposes biomechanical overload on the medial physis in the proximal tibia , resulting in the development of varus knees14 ) .
this can be explained by hueter - volkmann 's law stating that growth at the physes is retarded under increased compression , whereas accelerated under reduced loading .
such unbalanced stress on the epiphysis has also been associated with tibia vara in children15 ) .
some studies also suggested that vitamin d insufficiency in children could cause coronal bowing of the femoral shaft , coxa vara , and proximal tibia vara , eventually resulting in constitutional varus alignment16,17 ) .
nagamine et al.18 ) reported that medial torsion of the proximal tibia during kneeling and squatting in childhood in asian countries with floor - sitting lifestyle resulted in high prevalence of varus alignment compared to that in the western countries . likewise , although constitutional varus alignment has been addressed in a variety of studies , consensus is elusive ; therefore , further studies are required .
numerous studies have demonstrated the importance of correcting the mechanical alignment to 03 relative to the neutral axis19,20 ) .
however , parratte et al.21 ) reported that the incidence of revision at 15 years after tka was not significantly different irrespective of the extent of deviation from the neutral mechanical axis : revision was required in 15.4% in the mechanically aligned group with a mechanical axis of 03 ( n=292 ) and in 13% in the outlier group with a mechanical axis of beyond 0 3 ( n=106 ) .
therefore , they concluded that the mechanical axis goal of 03 had little practical value for predicting the longevity of tka implants .
in addition , the relationship between the outlier ( beyond 03 deviation from the neutral mechanical axis ) and the survival of tka implants or clinical outcomes has been shown weak correlations in some other studies22,23,24,25 ) . in our opinion , these studies suggest the need to reconsider whether restoration of neutral mechanical alignment and avoidance of outlier should also be applied to patients with constitutional varus knees .
based on literature review , bourne et al.26 ) reported that various factors , such as patient selection , surgical technique , and implant design , appeared to have an influence on dissatisfaction after tka that was noted in 11% to 25% of the patients .
still , we believe that careful consideration should be given as to whether such patient dissatisfaction could be attributable to the stereotypical goal of restoring neutral mechanical alignment that does not accommodate anatomical variations of patients .
first , there could have been some measurement errors caused by rotation of the lower limb or the observers ; however , we attempted to eliminate errors by taking radiographs in the same position , excluding volunteers with anatomical or congenital deformity to prevent errors due to rotation , and obtaining measurements from three observers to improve reliability .
this was because the prevalence of tka indicated for osteoar thritis was overwhelmingly high in females than men ( 9:1 ) in korea.27 ) we think further research involving male adults should also be conducted .
third , given the rapid economic development along with changes in lifestyle and diet in the past 50 years , it should be taken into consideration that there must be differences in the body shape , constitution , lifestyle , and nutrition between the current tka candidates and the study participants .
we believe that restoration of the original knee alignment based on thorough preoperative and intraoperative assessment of patient 's anatomical characteristics would be more beneficial in terms of clinical outcomes and longevity of tka than the traditional approach aimed at restoring stereotyped neutral mechanical alignment .
in our study , the mechanical axis of the lower limb was in slight varus ( 1.352.04 ) in the 118 korean females in their 20s and 30s and the incidence of constitutional varus alignment was 20.34% .
these findings may be useful in reconstruction procedures of the knee , including tka , unicompartmental knee arthroplasty , and high tibial osteotomy . | ### Summary:
: purposein total knee arthroplasty ( tka ) , it is important to restore neutral mechanical alignment .
the purpose of this study was to assess whether the lower limb alignment is neutral in healthy korean females and investigate the incidence of constitutional varus knees among them.materials and methodsweight - bearing full - leg standing radiographs were obtained from 118 healthy females between the ages of 20 to 39 years .
one radiologist and two orthopaedic surgeons measured the hip - knee - ankle angle ( hkaa ) , medial proximal tibial angle ( mpta ) , and femoral anatomic mechanical angle ( fama ) on the radiographs and compared with the traditional gold standard hkaa of 0 , mpta of 3 varus , and fama of 6.resultsthe interobserver reliability of the three independent observers was high ( p<0.001 ) .
the hkaa of the study subjects ( 1.352.04 ) was significantly different from the standard hkaa of 0 ( p<0.001 ) , but no statistically significant difference was observed in the mpta ( -3.181.61 ) and fama ( 5.990.70 ) from the standard values ( p=0.083 and p=0.887 , respectively ) .
the incidence of constitutional varus alignment was 20.34%.conclusionsin korean females , the mechanical axis of the lower limb was not neutral and the incidence of constitutional varus alignment was slightly higher than that in western females .
we believe that these findings should be taken into consideration in planning reconstructive surgery of the knee , such as tka , unicompartmental knee arthroplasty , and high tibial osteotomy . |
<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:
: altered membrane permeability is a hallmark of inflammation and incipient ischemia , as demonstrated by experimental , radiologic , and pathologic studies .
often , this is a systemic condition , involving retinal , cerebral , cardiac , pulmonary , and renal vessels .
the presence of microalbuminuria is a risk factor both in the general population or in elderly people.13 altered kidney function parameters further worsen the clinical course and prognosis of cardiovascular , cerebrovascular , and metabolic diseases.211 they are associated with white matter lesions,12,13 silent brain infarction,14 a high prevalence of stroke,15,16 worse prognosis , in terms of both short- and long - term morbidity and mortality,9,10 and recurrence of vascular events ( stroke , myocardial infarction , heart failure).10 pathologic renal findings are also described in young patients affected with stroke , mainly related to hypertensive cardiopathy , nephroangiosclerosis , and chronic pyelonephritis.17
lastly , renal dysfunction is related to cognitive impairment and dementia.1821 urinary polyclonal light chains are low to middle molecular weight proteins , filtered at the glomerular level and reabsorbed in the tubules by megalin - cubulin receptors.2225 in diabetes , the presence of polyclonal light chains is predictive of nephropathy in the absence of albuminuria.26 they herald systemic inflammation and progression of renal injury to chronic renal failure.27 the aim of the present study was to evaluate proteinuria and urinary polyclonal light chains in acute and chronic cerebrovascular disease .
five - hundred and fifty patients came under our observation from august 2008 to february 2010 , 36/553 ( 0.06% ) of whom bounced back .
they were recruited at the department of emergency and assistance or through the ambulatory service .
all the patients underwent routine blood and urine examinations , and had an electrocardiogram and computed tomography within 2448 hours .
the diagnoses were acute stroke in 139 ( 58 males , mean age 75.01 , standard deviation [ sd ] 10.85 , 81 females , mean age 80.27 9.04 ) , glasgow coma scale ( gcs ) 11.67 2.94 ; chronic cerebral vascular disease in 361 ( 162 males , mean age 73.78 10.33 , 199 females , mean age 77.61 8.67 ) , gcs 13.8 2.03 ; and other neurologic diseases in 50 patients ( 23 males , mean age 51.79 4.24 , 27 females , mean age 51.72 20.43 ) , gcs 14.56 1.61 .
serum parameters , ie , natremia , kalemia , glycemia , urea nitrogen , and creatinemia ( cre ) were detected by cobas integra 800 analyzer .
urinary samples were treated with 0.1 m hepes 0.1 m and 0.2 g / l sodium azide , then frozen and stored at 20c .
proteinuria and urinary light chains were analyzed by high - resolution agarose gel electrophoresis on sebia hydragel 2 if and hydragel 2 bence jones immunofixation with anti - light chain antibodies and detection by a semiautomatic hydrasis system .
some samples were analyzed by nephelometric immunoassay with specific anti - free light chain antibodies .
urinary tract infection and bence jones - positive samples were excluded from the statistical analysis .
this was performed using the unpaired t - test , for standard description of baseline characteristics and differences among the study groups , and by pearson correlation test and logarithmic regression analysis for identification of association between the study parameters .
serum parameters , ie , natremia , kalemia , glycemia , urea nitrogen , and creatinemia ( cre ) were detected by cobas integra 800 analyzer .
urinary samples were treated with 0.1 m hepes 0.1 m and 0.2 g / l sodium azide , then frozen and stored at 20c .
proteinuria and urinary light chains were analyzed by high - resolution agarose gel electrophoresis on sebia hydragel 2 if and hydragel 2 bence jones immunofixation with anti - light chain antibodies and detection by a semiautomatic hydrasis system .
some samples were analyzed by nephelometric immunoassay with specific anti - free light chain antibodies .
urinary tract infection and bence jones - positive samples were excluded from the statistical analysis .
this was performed using the unpaired t - test , for standard description of baseline characteristics and differences among the study groups , and by pearson correlation test and logarithmic regression analysis for identification of association between the study parameters .
our data showed proteinuria in 116/149 ( 78% ) acute stroke patients ( 26.85 42.39 mg / dl ) , 265/384 ( 69% ) chronic cerebrovascular disease patients ( 21.49 40.74 mg / dl ) , and 35/53 ( 66% ) patients with other neurologic diseases ( 17.81 37.17 mg / dl , see table 1 ) .
no statistically significant difference was found between proteinuria in acute stroke , chronic cerebrovascular disease , and other neurologic diseases .
urinary polyclonal light chains were mainly detected in cerebrovascular patients , with the highest significant levels of chains in acute stroke ( 24.16 26
l ; acute stroke versus other neurologic diseases , p 0.001 , and chronic cerebrovascular disease versus other neurologic diseases , p 0.01 .
mg / l in acute stroke , 11.97 51.70 mg / l in chronic cerebrovascular disease , and 4.98 4.27 mg / l in other neurologic diseases ( acute stroke versus other neurologic diseases , p 0.004 and chronic cerebrovascular disease versus other neurologic diseases , p 0.02 , figure 1 ) .
a trend towards a difference in the urinary polyclonal light chain ratio was found between acute stroke and other neurologic diseases ( acute stroke 2.62 1.0 , other neurologic diseases 2.15 0.74 , p 0.05 ) .
the polyclonal light chain / cre ratio was increased in acute stroke ( acute stroke /cre 0.42 0.47 ; acute stroke /cre 0.12 0.10 ) , but was relatively decreased in chronic cerebrovascular disease ( chronic cerebrovascular disease /cre 0.09 0.02 ; chronic cerebrovascular disease /cre 0.05 0.02 ) compared with acute stroke and other neurologic diseases ( other neurologic diseases /cre 0.17 0.11 ; other neurologic diseases /cre 0.06 0.01 ; and acute stroke /cre versus other neurologic diseases /cre , p 0.001 ; acute stroke /cre versus chronic cerebrovascular disease /cre , not statistically significant ; chronic cerebrovascular disease /cre ratio versus other neurologic diseases /cre ,
p 0.02 ; acute stroke /cre versus other neurologic diseases /cre , p 0.01 ; acute stroke /cre versus chronic cerebrovascular disease /cre , not statistically significant ; chronic cerebrovascular disease /cre versus other neurologic diseases /cre , p 0.04 , figure 2 ) . at case history ,
hypertension was referred by 127/149 ( 85.23% ) of acute stroke patients , 293/384 ( 76.3% ) of patients with chronic cerebrovascular disease , 18/53 ( 34% ) patients with other neurologic diseases , and diabetes was present in 29/149 ( 19.46% ) patients with acute stroke , 65/384 ( 16.92% ) with chronic cerebrovascular disease , and 1/53 ( 0.01% ) with other neurologic diseases .
no significant correlation was found for proteinuria , urinary polyclonal light chains , systolic , diastolic , and mean arterial pressure values , and natremia , kalemia , glycemia , urea nitrogen , and creatinemia .
our finding of a significant increase in urinary polyclonal light chains in acute and chronic vascular patients compared with those having other neurologic diseases , in the absence of a significant correlation with other systemic and renal parameters , suggests that urinary polyclonal light chains represent an early systemic marker of altered membrane permeability .
the higher and more significant level of compared with chains in acute stroke can be explained by their higher physiologic production , up to twice the rate of .22 their further increase in pathologic conditions is counterbalanced by augmented elimination and reduced reabsorption at the tubular level .
we observed a relatively insignificant increase in urinary chains in chronic cerebrovascular disease compared with acute stroke . in tubular proteinuria ,
an increase of urinary low molecular weight proteins , as dimers , was detected .
this is attributed to an increased excretion , a failure of proximal tubule reabsorption , and reduced catabolism.23 unfolding intermediates are found after exposure to denaturing conditions , such as urea , heat , and ph variation.25 higher seric concentrations of polyclonal light chains and a higher urinary polyclonal light chain / cre ratio , together with increased glomerular filtration and reduced reabsorption at the tubular level have been reported.24,27 serum and urinary concentrations of polyclonal light chains are related to the severity and progression of renal dysfunction.27 taken together , our data suggest that the increase in urinary polyclonal light chains may be a negative prognostic sign and represent the boundary between a reversible stage of renal dysfunction , namely nephrotic syndrome , in which there is still an opportunity for therapeutic intervention , and a definite progression to chronic kidney disease , indicated by a decreased polyclonal light chain / cre ratio .
this precedes an irreversible cascade of events characterized by reduction of glomerular filtration,27 systemic interstitial and parenchymal edema , infection , tubular necrosis , progression to uremia and irreversible renal failure , and need for emergency treatment , such as ventilatory assistance and hemodialysis .
therefore , it is important to prevent systemic complications that threaten the lives of patients , prolong hospitalization , cause frequent bounce - backs , diminish quality of life , and add further costs for sanitary assistance . the sensibility and specificity of such an assay for urinary polyclonal free light chains , their predictive role concerning short- and long - term prognosis , and the association with cardiac and renal echographic and magnetic resonance imaging parameters are under evaluation . | ### Summary:
: altered membrane permeability is a hallmark of inflammation and ischemia with systemic spreading .
renal dysfunction is a risk factor for cardiovascular , cerebrovascular , and metabolic diseases .
the aim of the present study was to assess proteinuria and urinary polyclonal light chains in acute stroke and chronic cerebrovascular disease compared with other neurologic diseases .
our results showed significantly increased levels of urinary polyclonal light chains in cerebrovascular disease compared with other neurologic diseases .
the highest values of urinary polyclonal chains were found in acute stroke compared with chronic cerebrovascular disease and other neurologic diseases , while the level of chains was mainly increased in chronic cerebrovascular diseases .
the shift to chronic renal failure seems to be signaled by a decreased polyclonal light chain / creatinemia ratio .
the absence of a significant correlation with blood pressure and other seric parameters suggests that polyclonal light chains are an early marker of reversible vascular impairment with renal dysfunction before progression to irreversible renal failure and need for dialysis and/or intensive care . |
<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:
: hypothyroidism is a relatively common problem worldwide often with insidious onset and is relatively asymptomatic .
it is divided in two stages : mild stage ( subclinical ) , or symptomatic ( overt ) .
a community survey carried out in the united states identified hypothyroidism in 4.6% of the us population : 0.3% had overt hypothyroidism and 4.3% had what was described as subclinical or mild hypothyroidism.1 subclinical hypothyroidism can progress to overt hypothyroidism , particularly in thyroid peroxidase ( tpo)-positive patients in whom the annual risk of developing overt hypothyroidism can approach 4%.2 there can be clinical manifestations in mild hypothyroid patients requiring hormone replacement therapy.3 hypothyroidism can affect all organ systems , and its manifestations are largely a function of the degree of hormone deficiency.3 there has been interest in the cardiorespiratory consequences of hypothyroidism as coronary heart disease , congestive heart failure , hypertension , pericardial effusion , and rhythm disturbances have been documented as complications of the hypothyroid state.49 furthermore , there is growing evidence regarding an association between subclinical hypothyroidism and atherosclerosis , coronary heart diseases , and hypertension.4,7,8,10 subclinical and overt hypothyroidism can lead to a variety of respiratory changes .
first , observational studies and case reports have associated hypothyroidism with obstructive sleep apnea ( osa).11,12 these studies report conflicting data : a high association between osa and hypothyroidism has been reported in some studies , while no association has been documented in others .
second , abnormalities in pulmonary function tests including a decrease in the diffusing capacity for carbon monoxide and an increased incidence of pleural effusions in patients with overt hypothyroidism have been reported.1315 alveolar hypoventilation is a particularly important issue among respiratory complications of hypothyroidism .
myxedema and hypothyroid states can cause depression of the hypoxic ventilatory drive which is responsive to hormone replacement therapy.16 in the extreme case of myxedema , respiratory depression can lead to alveolar hypoventilation and progressive hypoxemia , and ultimately to marked hypercapnia and coma.17 in addition , mild respiratory muscle weakness proportional to the degree of thyroid dysfunction is a common finding in primary and iatrogenic hypothyroid states of short duration .
this weakness , which affects both inspiratory and expiratory muscles , is reversible with treatment.18 the current study utilized a simple and noninvasive method to evaluate alveolar ventilation in ambulatory hypothyroid patients ( both clinical and subclinical ) , focusing particularly on ventilation in patients suffering from subclinical hypothyroidism .
the study examined the hypothesis that changes in ventilation differ significantly between patients with mild ( subclinical ) and overt ( clinical ) thyroid hormone deficiency , and that these two groups differ from healthy controls .
sixty - four ambulatory adult females aged 1865 years referred to a university - affiliated endocrinology clinic with clinical suspicion of thyroid disease were selected and enrolled in this study .
the study was approved by the local ethics committee and written informed consent was obtained from each subject . for selection , subjects underwent a comprehensive history and physical examination , and medical , drug , and habitual history were taken into consideration . in particular , history of oral contraceptives , salicylates , methylxanthines , and -adrenergic administration ; presence of any cardiorespiratory , renal , or endocrinologic diseases potentially affecting respiration ; and habits such as smoking of any kind and duration , drug use , or opiate consumption were considered as exclusion criteria .
all subjects were clinically evaluated by an endocrinologist for evidence of thyroid disease and categorized on the basis of thyroid hormone levels . physical examination revealed goiter in some patients ; however these were not large enough to affect the respiratory system .
thyroid - stimulating hormone ( thyrotropin , tsh ) and free thyroxine ( ft4 ) were measured in all subjects using a radioimmunometric assay .
the normal ranges for tsh and ft4 were considered to be 0.34.2 u / ml and 0.81.7 ng / dl , respectively .
end - tidal carbon dioxide ( et - co2 ) was measured in all subjects using a capnograph ( microstream ; oridion , needham , ma ) , which is a portable monitor that measures and displays et - co2 values and respiratory rates .
it has a nasal prong and an oral cannula extending downward . in this study , after inserting the nasal prong into the nostrils , a normal capnographic waveform was recorded after 25 minutes . to achieve a power of 80% with a type i error rate of 0.05
the mean value of three independent measurements was considered to be the et - co2 value of the individual .
statistical analysis was performed with spss software ( version 16.0 for windows ; spss inc .
, chicago , il ) , analysis of variance ( anova ) , and student s t - test .
a spearman correlation test was used to identify correlations between values in the experimental groups .
ninety - five individuals were included in the study : 33 with subclinical hypothyroidism , 31 with overt hypothyroidism , and 31 healthy controls .
the mean ages and bmi measurements for each of the groups were comparable and are summarized in table 1 .
mean values for tsh , ft4 , and et - co2 for each of the three groups are presented in table 2 .
mean et - co2 values for the subclinical hypothyroidism group was significantly lower than those for healthy controls ( 31.79 2.75 vs 33.81 2.38 ; p = 0.012 ) .
moreover , mean et - co2 values for the overt hypothyroidism group were significantly lower than those for healthy controls ( 32.13 3.07 vs 33.81 2.38 ; p = 0.048 ) .
nonetheless , mean et - co2 values for overt and subclinical hypothyroidism groups were comparable ( p > 0.05 ) .
analysis of data for relationship between et - co2 values and tsh levels revealed a significant correlation ( r = 0.24 ; p = 0.01 ) .
however , et - co2 values were not correlated with ft4 levels ( r = 0.13 ; p = 0.20 ) .
there was a statistically significant positive correlation between et - co2 values and bmi measurements ( r = 0.288 ; p = 0.005 ) .
however , there was no significant correlation between et - co2 values and respiratory rate or age of the subjects ( p > 0.05 ) .
most studies on the relationship between hypothyroidism and alveolar ventilation emphasize the depression of respiratory system in hypothyroidism .
zwillich et al demonstrated that myxedema and the hypothyroidism state after thyroid ablation depressed the hypoxic ventilatory drive , and that this depression was responsive to thyroid hormone replacement therapy.16 in addition , depression of the hypercapnic ventilatory drive was reported in myxedema but this relationship was not significant in individuals suffering from milder hypothyroidism , and there was no improvement after hormone replacement therapy . in the present study ,
a simple and noninvasive method was used to evaluate the alveolar ventilation in patients with thyroid hormone deficiency .
alveolar ventilation , the main determinant of arterial and et - co2 levels , is defined as the portion of minute ventilation that reaches the alveoli and participates in gas exchange . in our study ,
minute ventilation inferred from et - co2 was significantly higher in subjects suffering from subclinical hypothyroidism than those with overt hypothyroidism or healthy controls .
this would suggest that patients with thyroid hormone deficiency , particularly mild ( subclinical ) or moderate , hyperventilate relatively more often compared to normal individuals . a year - long study by pandya et al documented four cases of severe hypothyroidism with long - term dependency on ventilators ; thyroid hormone replacement therapy was successful in weaning three of the subjects off the ventilation.19 similarly , several retrospective studies have confirmed ventilatory dependency in hypothyroidism patients.20 there have been reports related to co2 retention in myxedema coma.13 it has been reported that hypothyroidism can cause weakness of inspiratory and expiratory muscles , and that respiratory pump failure could be secondary to muscle weakness in severe hypothyroidism.18 furthermore , a study by baldwin et al demonstrated that thyroid deficiency in rats limited the endurance capacity of skeletal muscles.21 diaphragmatic dysfunction ranging from mild weakness to severe forms of diaphragmatic paralysis and phrenic nerve neuropathy are proposed as mechanisms of respiratory failure in patients with thyroid hormone deficiency.22,23 in the present study , the patients with mild / moderate hypothyroidism presented with higher minute ventilation , rather than lower , compared to the healthy controls .
this paradoxical result may be related to direct stimulatory effect of trh on ventilation while no muscular weakness has settled in yet .
another explanation for this apparently discrepant finding would be the effect of secondary changes in the lung with lung juxtacapillary receptor stimulation that in turn increases ventilation with lowering arterial and et - co2 values .
therefore , it seems that even though severe hypothyroidism is an etiological factor in alveolar hypoventilation , it is unclear what relationship , if any , exists between subclinical and mild symptomatic hypothyroidism and the pulmonary ventilation system .
the respiratory system is controlled by the autonomic nervous system but hormones also play a role . in a comprehensive article regarding breathing and hormones
, saaresranta demonstrated that a number of hormones , including thyrotropin - releasing hormone ( trh ) , are involved in controlling the breathing.24 there is a growing body of evidence that there is an association between trh and the respiratory system . injecting trh into an important component of the rostral ventrolateral medulla , the retrotrapezoid nucleus , of anesthetized rats had powerful stimulatory effects on the product of integrated phrenic amplitude and frequency , and this response was dose - dependent.25 there was an increase in ventilation , o2 consumption , and body temperature after trh injection into the retrotrapezoid nucleus in conscious rats , and it was concluded that trh could have an important role as a state - dependent modulator of breathing control.26 it has also been demonstrated that intracerebroventricular application of trh induces a dose - dependent and sustained increase in the ventilation rate , relative tidal volume , and relative respiratory minute volume . 27 a study carried out on anesthetized , vagotomized , paralyzed , and artificially ventilated rabbits concluded that microinjection of trh into different regions of the medullary respiratory center exerted a depressant effect on respiration at medullary levels by acting on rostral expiratory neurons , but emphasized that trh could have stimulatory effects if injected into other regions of the respiratory center.28 despite numerous studies , the exact physiological effect of trh on the respiratory system and its participation in the adjustment of breathing during disease has not been elucidated . in the present study ,
mean et - co2 values were lower in subclinical hypothyroid patients than in the control group .
in addition , there was no correlation between mean tsh and ft4 levels , and et - co2 values . the ultimate test to assess adequate ventilation
is the invasive determination of partial pressure of co2 in arterial blood , but capnography , utilized in this study , provides information concerning ventilation , perfusion , and metabolism.29 however , some studies have demonstrated a correlation between et - co2 and arterial co2 levels.30,31 several pathophysiological mechanisms , ranging from neuromuscular and pulmonary factors such as diaphragmatic and respiratory muscle weakness , to central factors such as decreased ventilatory drive , can be considered as causes of respiratory failure and resulting hypercapnia . in severe hypothyroidism ,
myxedematous involvement of respiratory muscles and depression of both the hypoxic and hypercapnic ventilatory drive can cause alveolar hypoventilation and co2 retention , which in turn can contribute to the development of myxedema.3 however , in mild symptomatic or subclinical hypothyroidism , interactions between hormonal changes such as increased trh and/or tsh and neuromuscular and pulmonary changes affecting respiratory function could be important .
measurements of tsh and ft4 are sufficient for diagnosis and the categorization of hypothyroid patients , but measuring serum levels of ft4 would have been of use in defining relationships between variables .
unlike patients suffering from severe hypothyroidism and myxedema , asymptomatic or mild symptomatic hypothyroid patients are often regarded as stable in terms of clinical status .
interactions between several factors affect the respiratory system including neurohumoral , neuromuscular , and pulmonary factors .
hypothyroidism , particularly at the subclinical stage , results in hyperventilation as demonstrated by a low et - co2 .
it is possible that such patients demonstrate increased alveolar ventilation in relation to co2 production . | ### Summary:
: backgroundhypoventilation is a frequently suspected complication of hypothyroidism.objectivein this study we examined the hypothesis that changes in alveolar ventilation , as measured by end - tidal carbon dioxide ( et - co2 ) , differ between patients with mild ( subclinical ) and overt ( clinical ) thyroid hormone deficiency , and both differ from healthy control subjects.methodsa total of 95 subjects , including 33 with subclinical hypothyroidism ( an elevated thyroid - stimulating hormone ( tsh ) level and a normal thyroxin ( ft4 ) level ) , 31 with overt hypothyroidism ( elevated tsh and decreased ft4 ) , and 31 healthy controls .
all subjects were female and were evaluated clinically by an endocrinologist for evidence of thyroid disease and categorized on the basis of thyroid hormone levels . et - co2 was measured using a capnograph .
et - co2 levels were measured three times and the mean value was considered as the mean level for the individual.resultsmean et - co2 values of the subclinical hypothyroidism group were significantly lower than those of the healthy controls ( 31.79 2.75 vs 33.81 2.38 ; p = 0.01 ) .
moreover , mean et - co2 values for the overt hypothyroidism group were significantly lower than those for healthy controls ( 32.13 3.07 vs 33.81 2.38 ; p = 0.04 ) .
there was a significant correlation between et - co2 values and tsh levels ( r = 0.24 ; p = 0.01 ) .
however , et - co2 values were not correlated with ft4 levels ( r = 0.13 ; p = 0.20).conclusionsalveolar ventilation , as inferred from lower et - co2 levels , is higher in subjects with subclinical hypothyroidism and overt hypothyroidism ( lower et - co2 ) than in healthy controls .
furthermore , et - co2 levels have no relationship to the levels of tsh or ft4 .
the lower et - co2 in these patients with hypothyroidism , particularly at the subclinical stage , suggests presence of hyperventilation , which may be related to direct effect of trh on respiratory center or to local changes within the lung . |
<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:
: chylothorax is an infrequent but a serious complication of pediatric cardiovascular surgery and could often jeopardize postoperative recovery .
the incidence of this condition has been increasing over the past decades , possibly due , in part , to the increased complexity of cardiac surgery.1 central venous obstruction , which is often related to the insertion of central venous catheters for postoperative management,2,3 is known to be an important risk factor for treatment failure and mortality associated with this condition.47 in this report , we present the case of an infant with prolonged chylothorax associated with thrombosis or obstruction of the superior vena cava ( svc ) .
the patient was a 6-month - old girl with a small right ventricle ( 70% of normal ) who underwent surgical correction of tetralogy of fallot .
she had postoperative heart failure represented by low cardiac output and elevated central venous pressure of 13 mmhg .
examination of the drained fluid revealed cell counts of 4,250 cells/l with a predominant lymphocyte fraction of 99% .
the triglyceride levels were as high as 144 mg / dl , which confirmed that she had chylothorax .
because the chylous drainage did not reduce with the generally recommended conservative therapy , including water restriction ( 60 ml kg day ) and total parenteral nutrition , we initiated administration of a somatostatin analogue at a dose of 10 g kg h on postoperative day 7 .
nonetheless , chylous drainage persisted , and thoracic duct ligation was performed on postoperative day 35 .
although chylous drainage temporarily decreased after the surgery , it did not stop completely and increased gradually while supportive therapies , including water restriction , total parenteral nutrition , and somatostatin analogue infusion , were continued .
an echocardiogram on postoperative day 70 revealed stenosis of the svc due to large thrombi ( fig .
a central venous catheter had been placed in the right internal jugular vein from postoperative day 0 to 10 and from day 28 to 58 .
an important observation was that there was an unexpected decrease in the platelet count from 444 10/l on postoperative day 44 to 152 10/l on postoperative day 54 .
thrombosis developed despite the administration of tissue plasminogen activator followed by continuous infusion of heparin .
therefore , we performed stent implantation in the svc ( express ld 8 mm 27 mm ) and innominate vein ( express ld 7 mm 17 mm ) on postoperative day 102 ( fig .
3 ) . stent implantation dramatically reduced the chylous drainage from 40 ml kg d to 3.5 ml kg d ( averaged during the 5 days before and after the procedure ) .
the chest tube was successfully removed , and the patient was finally discharged from the hospital with diuretics and dietary control with milk enriched with medium - chain triglycerides .
the patient was a 6-month - old girl with a small right ventricle ( 70% of normal ) who underwent surgical correction of tetralogy of fallot .
she had postoperative heart failure represented by low cardiac output and elevated central venous pressure of 13 mmhg .
examination of the drained fluid revealed cell counts of 4,250 cells/l with a predominant lymphocyte fraction of 99% .
the triglyceride levels were as high as 144 mg / dl , which confirmed that she had chylothorax .
because the chylous drainage did not reduce with the generally recommended conservative therapy , including water restriction ( 60 ml kg day ) and total parenteral nutrition , we initiated administration of a somatostatin analogue at a dose of 10 g kg h on postoperative day 7 .
nonetheless , chylous drainage persisted , and thoracic duct ligation was performed on postoperative day 35 .
although chylous drainage temporarily decreased after the surgery , it did not stop completely and increased gradually while supportive therapies , including water restriction , total parenteral nutrition , and somatostatin analogue infusion , were continued .
an echocardiogram on postoperative day 70 revealed stenosis of the svc due to large thrombi ( fig .
a central venous catheter had been placed in the right internal jugular vein from postoperative day 0 to 10 and from day 28 to 58 .
an important observation was that there was an unexpected decrease in the platelet count from 444 10/l on postoperative day 44 to 152 10/l on postoperative day 54 .
thrombosis developed despite the administration of tissue plasminogen activator followed by continuous infusion of heparin .
therefore , we performed stent implantation in the svc ( express ld 8 mm 27 mm ) and innominate vein ( express ld 7 mm 17 mm ) on postoperative day 102 ( fig .
3 ) . stent implantation dramatically reduced the chylous drainage from 40 ml kg d to 3.5 ml kg d ( averaged during the 5 days before and after the procedure ) .
the chest tube was successfully removed , and the patient was finally discharged from the hospital with diuretics and dietary control with milk enriched with medium - chain triglycerides .
chylothorax is a serious complication of cardiac surgery and is associated with increased mortality . because the thoracic duct enters the venous system at angulus venosus , central venous obstruction in the upper body and/or high central venous pressure inevitably causes resistance to the flow of the lymph into the venous system , which leads to congestion of the lymph thus resulting in chylous drainage into the pleural space.8,9 this pathophysiology is directly linked to the well - recognized clinical finding that central venous obstruction and/or high central venous pressure is often associated with prolonged high volume of chylous drainage and is a significant risk factor for treatment failure.47,10 central venous catheterization required for administration of medication or parenteral nutrition after cardiac surgery is known to be an important cause of central venous thrombosis.2,3,11 once chylothorax develops , prolonged chylous drainage , in turn , necessitates the use of a central venous catheter for a prolonged period for parenteral nutrition , which potentially leads to a viscous cycle of thrombosis formation and chylous drainage .
antithrombin lost in chyle2,12 and/or vascular inflammation induced by hyperalimentation solution2 may also contribute to increased susceptibility for the development of thrombosis in patients with chylothorax . in our patient , chylothorax developed soon after surgery , which suggested that operative injury to the thoracic duct was the primary cause of chylothorax.1 elevated central venous pressure possibly associated with an underdeveloped right ventricle could have further accelerated and prolonged the chylous drainage .
formation of venous thrombosis was also believed to have contributed significantly to the refractory chylous drainage observed even after thoracic duct ligation , because chylothorax resolved after the venous obstruction was relieved by stent implantation .
nath et al reported an important finding that although the overall outcome of surgical thoracic duct ligation for chylothorax refractory to conservative medical therapy is excellent , patients with upper body venous thrombosis were at a high risk of treatment failure and mortality.7 considering the clinical course and the huge size of the thrombus formed in our patient , it might be assumed that the process of thrombus formation might have started much earlier than we recognized it .
thus , the findings in our patient and those in previous reports indicate the importance of high index of suspicion for central venous thrombosis and obstruction , especially in patients with refractory chylothorax . a decrease in platelet count ,
as observed in our patient , and possibly an increase in the level of d - dimers may provide useful information for this purpose . conventionally , surgical intervention is indicated when conservative therapy fails to control the lymphatic leak ; however , specific and precise criteria for abandoning conservative therapy remain to be standardized.1,6,11 a consensus for treatment of chylothorax with central venous stenosis / occlusion remains to be established . to our knowledge , this is the first report on stent implantation for stenosis of the svc due to thrombosis for effective treatment of otherwise uncontrollable chylothorax after congenital cardiac surgery .
our findings are in line with those reported in an infant born with congenital svc obstruction in whom successful placement of an intravascular stent led to the resolution of the chylothorax with rapid clinical improvement.13 balloon angioplasty can be an alternative to stent implantation , but in our patient , the treatment efficacy of stenting was greater than that of balloon dilation .
administration of anticoagulants or thrombolytics may be effective in some patients with chylothorax associated with thrombosis,3,11 but these drugs were ineffective in our patient .
central venous thrombosis and resultant venous stenosis / occlusion can cause a life - threatening refractory chylothorax after congenital heart surgery .
stent implantation can effectively relieve the venous obstruction and thus be a life - saving treatment option for this difficult condition .
thus , physicians should maintain a high index of suspicion for venous obstruction when chylothorax is diagnosed and is resistant to conservative therapy . | ### Summary:
: chylothorax is a serious complication of congenital cardiac surgery and is significantly associated with increased morbidity and mortality .
central venous obstruction , which is often related to the insertion of central venous catheters for postoperative management , is known to be an important risk factor for treatment failure and mortality associated with this condition .
we present the case of a 6-month - old girl with refractory chylothorax after surgical repair of tetralogy of fallot .
the chylous drainage continued for more than 2 months despite maximal conservative therapy ( water restriction , total parenteral nutrition , and infusion of somatostatin and steroid ) and surgical ligation of the thoracic duct .
subsequently , we observed stenosis of the superior vena cava ( svc ) caused by large thrombi possibly associated with the prolonged use of central venous catheter placed in the internal jugular vein . because transcatheter balloon dilation failed to relieve the stenosis , we performed stent implantation for the svc and innominate vein .
after the procedure , chylous drainage dramatically reduced , and the patient was discharged from the hospital . in conclusion , central venous obstruction due to thrombosis should be routinely examined when chylothorax is diagnosed and is resistant to conservative therapy after congenital heart surgery .
stent implantation can effectively relieve the venous obstruction and thus be a life - saving treatment option for this difficult condition . |
<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:
: acute kidney injury ( aki ) secondary to immersion and near - drowning is rarely described and poorly understood .
much of the literature of near - drowning has concentrated on the respiratory effects of aspiration of salt and freshwater , and on the management of both early and late respiratory complications such as aspiration pneumonia and adult respiratory distress syndrome ( 1 ) . however , near - drowning and immersion can have profound effects on other end organs such as cerebral ( hypoxic brain injury , cerebral edema ) ( 2 ) , cardiac ( atrial fibrillation ) ( 3 ) and hematologic complications ( coagulopathy and hemolysis ) ( 4 ) .
moreover , multisystem failure resulting from near - drowning is also well described ( 5 ) .
near - drowning induced acute kidney injury ( aki ) is not uncommon and is heterogenous clinical entity ( 6 ) .
although the resultant aki is usually mild and self - limited , severe cases such as aki associated with shock , multisystem failure , rhabdomyolysis ( 7 , 8) and isolated aki can occur ( 6 ) . only few cases of severe isolated aki due to acute tubular necrosis ( atn ) resulting from near - drowning exist in the literature .
we report a case of near - drowning who developed severe isolated aki requiring dialysis due to biopsy - confirmed atn .
a 21-yr - old man was admitted to this hospital because of anuria and nausea on june 11 , 2011 .
he had been well until 3 days before admission , when he went to swim in the lake with his friends .
he was unconscious briefly ( about 2 - 3 min ) until rescued by his friend .
, he was conscious but sleepy ; blood pressure was 132/68 mmhg , body temperature was 36.9 , and pulse was 114 beats per minute ; respiration was 20 per minute , and the oxygen saturation was 96% while the patient was breathing ambient air .
laboratory tests revealed serum creatinine level of 1.4 ( 0.4 - 1.3 ) mg / dl , total carbon dioxide ( tco2 ) of 9.8 ( 24 - 30 ) mm / l , anion gap of 27.2 mm / l , hemoglobin concentration of 16.7 g / dl , and leukocyte count of 12,300/l ( lymphocyte 41.1% ) .
he was admitted to our hospital 3 days later , complaining of being tired , anorexic and anuric .
the vital signs were as follows : blood pressure , 140/90 mmhg ; pulse , 75 beats per minute ; respiration , 20 per minute ; and body temperature , 37.6. laboratory findings showed blood urea nitrogen ( bun ) of 42.7 ( 6 - 26 ) mg / dl , serum creatinine of 11.5 mg / dl , seum cystatin c level of 3.39 ( 0.5 - 1.10 ) mg / l , aspartate aminotransferase ( ast ) of 6 ( 10 - 40 ) iu / l , alanine aminotransferase ( alt ) of 9 ( 6 - 40 ) iu / l , lactate dehydrogenase ( ldh ) of 435 ( 218 - 472 ) iu / l , creatine kinase ( ck ) of 225 ( 5 - 217 ) u / l , myoglobin of 87.9 ( 15.2 - 91.2 ) ng / ml , tco2 of 15.4 ( 20 - 28 ) mm / l , anion gap of 19.3 mm / l , hemoglobin concentration of 13.1 g / dl , and leukocyte count of 11,180/l ( segmented neutrophil 86.5% , lymphocyte 8.1% ) .
the hourly urine output was less than 10 ml despite of bolus infusion of normal saline and continuous infusion of furosemide .
non - contrast enhanced abdominal computed tomography showed normal sized kidneys without urinary tract obstruction . a bone imaging study using
the patient needed five sessions of dialysis over the succeeding 5 days and serum creatinine level was 5.12 mg / dl on the next day after the last hemodialysis session , then we stopped hemodialysis treatment . on the 9th hospital day , serum creatinine level was 3.05 mg / dl , we planned renal biopsy that had been postponed because of bleeding risk .
the next day , serum creatinine level was 1.98 mg / dl and renal biopsy was performed .
the renal tubular epithelial cells were denuded and had exfoliating brush borders and intermittent mitosis due to regeneration .
the interstitium was edematous and had mild infiltration of lymphocytes , but the glomeruli showed unremarkable finding ( fig .
the patient 's renal function recovered spontaneously , 1.24 mg / dl 3 weeks later and 1.07 mg / dl 5 weeks later .
aki secondary to near - drowning is not uncommon , but the resultant severe aki requiring dialysis is exceedingly rare : we found only 7 reported cases , including the present report ( 6 - 10 ) .
the two other cases were related with rhabdomyolysis ( 7 , 8) , 1 case resulted from hypothermia ( 9 ) , 1 case were related with both ( 10 ) , and 2 cases had isolated aki ( 6 ) .
( 6 ) ; usually the term means that disproportionately severe aki even several days after the immersion episode who did not require cardiopulmonary resuscitation ( cpr ) or did not experience shock , hypothermia or myoglobinuria after their near - drowning .
this case is the third report of severe isolated aki in the literature and first report in korea .
immersion and drowning injury has been widely reviewed ( 1 - 3 ) , and widespread tissue hypoxia and subsequent reperfusion injury are thought to be the predominant underlying pathophysiology , although hypovolemia and hypothermia may also contribute to tissue damage .
the initial event leading to tissue injury in kidney ischemia - reperfusion injury ( iri ) is the acute reduction of blood flow that produces hypoxia - induced vascular and tubular dysfunction . following reperfusion
, various intracellular events occur that lead to cellular dysfunction , apoptosis and cell death ( 11 ) .
the morphological changes occur mainly in proximal tubules , susceptible to ischemic injury , including loss of polarity , loss of the brush border ( 12 ) , and redistribution of integrins and na / k - atpase to the apical surface ( 13 ) .
calcium ( 14 ) and reactive oxygen species ( 15 ) may also have a role in these morphological changes , in addition to subsequent cell death resulting from necrosis and apoptosis .
both viable and nonviable cells are shed into the tubular lumen , resulting in the formation of casts and luminal obstruction and contributing to the reduction in the gfr ( 16 ) .
inflammation is also an important early event leading to intracellular responses that ultimately result in apoptosis and necrosis .
the involvement of the immune system in kidney iri is very complex ; dendritic cells and macrophages may contribute early in the innate immune response to kidney iri and promote neutrophil infiltration ( 17 ) , while t regulatory cells have been shown to suppress the extent of kidney iri through an il-10 dependent mechanism ( 18 ) .
dendritic cells , neutrophils , phagocytic macrophages and lymphocytes participate in the early phase of kidney iri as well as the late reparative phase ( 19 ) .
a retrospective study to assess clinical predictors of near - drowning associated aki concluded that lymphocytosis may also predict renal impairment ( 6 ) . in our case , the patient had not lymphocytosis but mild lymphocyte infiltration in interstitium was seen .
metabolic acidosis is common after near - drowning , and is due to lactic acidosis induced by tissue hypoxia ( 5 , 20 ) .
that lactate was the probable cause of acidosis supported by the increased anion gap and reversible nature of the acidosis .
in this case , unfortunately , serum level of lactic acid and arterial blood gas analysis just after immersion episode were not checked , but severe high anion gap metabolic acidosis was seen on presentation .
the acidosis was quickly corrected , but the initial mild renal dysfunction progressed to establish severe aki and required supportive dialysis .
why renal injury predominates in the absence of other post - immersion injury sequelae is not known .
the possible explanation is renin - angiotensin surge when returning to dry land after whole - body immersion may play a role ( 3 ) . although the pathology of isolated aki is controversial , renal hypoxia and subsequent reperfusion injury play major role in developing severe aki due to atn in our case .
it is plausible that the patient had not hemodynamic instability , hypothermia or rhabdomyolysis that related with aki after near - drowning . in summary , we describe a case of severe isolated aki caused by near - drowning .
to the best of our knowledge , this is the first such case report in korea .
our case differs from the 2 other cases we reviewed in the literature in that our patient 's aki was confirmed by kidney biopsy as atn .
although near - drowning associated aki is usually mild and self - limited , severe aki required dialysis can occur even several days after immersion event , it is recommended that any patient who presents after near - drowning or immersion should be assessed for potential aki . | ### Summary:
: acute kidney injury ( aki ) secondary to near - drowning is rarely described and poorly understood . only few cases of severe isolated aki resulting from near - drowning
exist in the literature .
we report a case of near - drowning who developed to isolated aki due to acute tubular necrosis ( atn ) requiring dialysis .
a 21-yr - old man who recovered from near - drowning in freshwater 3 days earlier was admitted to our hospital with anuria and elevated level of serum creatinine .
he needed five sessions of hemodialysis and then renal function recovered spontaneously .
renal biopsy confirmed atn .
we review the existing literature on near - drowning - induced aki and discuss the possible pathogenesis . |
<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:
: hypertension peculiar to pregnancy ( preeclampsia and gestational hypertension ) is a pregnancy specific syndrome characterized by reduced organ perfusion secondary to vasospasm and endothelial pathology .
there are several hall mark studies which have already established the two arms of the fetal circulation ( middle cerebral artery pulsatility index and umbilical artery pulsatility index ) both in normal and compromised fetuses .
we felt that the actual problem starts from uterine vessels and finally the changes are reflected in the cerebral circulation .
we wanted to compare whether alterations in uterocerebral ratio reflect the flow dynamics better than umbilical - cerebral ratio .
the vascular changes in these conditions can be reflected in doppler studies well in advance compared to the conventional antenatal tests of fetal well - being .
the brain sparing effect is maximum 2 or 3 weeks before the occurrence of late decelerations on cardiotocogram , suggesting that patient with a high risk for unfavorable pregnancy outcome may have alteration in the blood flow in the middle cerebral artery 2 - 3 weeks prior to the delivery [ 1 , 2 ] . as placental insufficiency occurs
, several changes occur in fetal circulation , culminating with the brain sparing , characterized by blood flow redistribution with priority to important organs like brain and heart adrenals at the expense of spleen , kidney , and peripheral circulation .
cerebroplacental ( cp ) ratio is a well - established predictor of unfavorable pregnancy outcomes , while cerebrouterine ( cu ) ratio is fairly new ratio of vascular impedance between mca and uterine arteries , which has not been commonly evaluated .
the intent of this study was to know which of the two parameters would help us to predict the perinatal outcome better .
our hypothesis was , therefore , that mca / uterine artery pi ratio could have a better predictive value for unfavorable outcome than the cp ratio .
this was a prospective observational study , which was carried out over a period from september 2012 to september 2013 , in the department of obstetrics and gynecology , in tertiary care center .
eligible participants were those women with singleton pregnancy diagnosed with hypertension peculiar to pregnancy ( preeclampsia and gestational hypertension ) , after 26 weeks of gestation .
women with history of chronic hypertension , chronic renal disease , diabetes mellitus , and secondary hypertension due to immunological disease such as sle and apla syndrome and women in active labor or those with premature rupture of membranes were excluded .
serial scans by transabdominal route were performed for interval growth and doppler parameters ( umbilical , middle cerebral artery , and uterine artery doppler ) .
the biometric parameters were plotted on a customized growth chart to look for any evidence of intrauterine growth restriction .
doppler ultrasound was performed as soon as the diagnosis of preeclampsia / gestational hypertension was made .
the procedures followed were in accord with the ethical standards of the committee on human experimentation of our institution . written informed consent was taken from all patients after hospital ethical committee approval .
preeclampsia was defined as a pregnancy specific syndrome characterized by blood pressure > 140/90 mm of hg after 20 weeks of gestation with proteinuria > 300 mg/24 hrs or persistent 1 + random dipstick proteinuria and was considered to be severe when associated with blood pressure > 160/110 mm , thrombocytopenia ( platelets less than 100,000/l ) , renal insufficiency ( creatinine greater than 1.1 mg / dl or doubling of baseline ) , liver involvement ( serum transaminases levels twice the normal ) , cerebral involvement ( headache , visual disturbances , persistent nausea or vomiting ) , or pulmonary edema .
gestational hypertension was defined as blood pressure > 140/90 mm of hg after 20-week period of gestation with no proteinuria , and blood pressure returns to normal in less than 12 weeks postpartum .
fetal hypoxia was said to exist antenatally , whenever there was absent end diastolic flow or reversal of flow in the umbilical artery , suboptimal nst , and intranatally , when there was thick meconium staining of the amniotic fluid and ominous cardiotocographic changes ( persistent and prolonged bradycardia , loss of beat to beat variability , etc . ) .
scan was done in recruited patients using philips hd 11xe machine using 35 mhz transabdominal probe .
doppler velocity of uterine artery was recorded at the point at which they crossed over the external iliac artery cranial to crossing of iliac artery .
the middle cerebral artery was located by color doppler in a transverse view of fetal brain .
the pulsed doppler sample gate was placed on the vessel about 1 cm of the origin of mca from the circle of willis towards lateral edge of orbit .
the umbilical artery pi was obtained from free loop of umbilical cord during fetal apnea .
cerebrouterine ratio ( middle cerebral artery to uterine artery pi ratio ) and cerebroplacental ratio ( middle cerebral artery to umbilical artery pi ratio ) were estimated .
cerebrouterine ( cu ) ratio was plotted on the chart ; < 5th percentile was considered as decreased or abnormal .
cerebroplacental ( cp ) ratio was considered as abnormal or to have brain sparing effect , when ratio was < 1.08 .
the abnormal outcomes studied were small for gestational age , low apgar , preterm delivery , hyaline membrane disease , assisted ventilation , academia , and overall perinatal outcome .
table 1 shows the composite score used to calculate the overall perinatal outcome , as more than one adverse outcome was present in many cases .
basic score values of 0 , 1 , or 2 were assigned to the five outcome variables ( birth weight , perinatal death , apgar at 5 min , respiratory problems , acidemia , and seizure ) , and the basic score values were summed to obtain an outcome score which was called as modified tchirikov composite score for perinatal outcome .
this score was constructed after the data had been collected for each new born before further statistical evaluation of overall perinatal outcome .
the data collected was analyzed using statistical package for social sciences ( spss , version 16 ) .
the validity of the predictive values was analyzed using sensitivity , specificity , and positive and negative predictive values and chi - square test was used for testing statistical significance .
patange and goel have reported that the cerebroumbilical ratio in normal pregnancy is 1.77 0.43 .
they noticed that this ratio is reduced to 1.47 ( difference of 0.3 ) when there was placental insufficiency .
based on this information , we calculated sample size with the formula
( 1)n=2z1/2+z1201/2 ,
where z1/2 is equal to 1.96 ( for = 0.05 , i.e. , type i error ) , z1 is equal to 0.84 ( for = 0.20 , i.e. , type ii error ) , 0 1 is equal to the difference of means ( 0.3 as in quoted study ) , and is the standard deviation .
accordingly , the sample size required is 32 and our sample size of 100 is far more than adequate .
the patient profile has been described in table 2 . there were a total of 100 cases at initial recruitment ( 72 primigravidae and 28 multigravidae ) ,
gestational hypertension was seen in 64 patients , and 36 had preeclampsia . out of these 100 cases ,
5 cases were lost for followup ; thus , perinatal outcome was analysed in 95 patients . each outcome measure and its relation to cerebrouterine ratio and cerebroplacental ratio were analysed .
as prematurity and intrauterine growth restriction can be confounding factors for nicu admission and hyperbilirubinemia ; these outcomes were neither correlated with doppler findings nor were they considered for composite scoring . out of 95 babies , 48 ( 50.5% ) babies required nicu admission for more than 24 hours .
there were 53/95 ( 55.7% ) premature babies of which 34/95 ( 68% ) were below 34 weeks of gestation .
low apgar ( less than 7 at 5 minutes of birth ) was seen in 16/95 babies ( 16.8% ) , 23/95 babies ( 24.2% ) required assisted respiration , acidemia was present in 10/95 babies ( 10.5% ) , hyperbilirubinemia was present in 33/95 ( 34.7% ) , and neonatal seizures were seen in only 1/95 ( 1.05% ) .
perinatal mortality was present in 5/95 ( 5.2% ) cases of which one was intrauterine fetal death .
when cu and cp ratios were compared , in abnormal cu ratio group , sga ( 47.4% versus 26.3% ) , acidemia ( 18.4% versus 5.3% ) , fetal hypoxia ( 50% versus 22.8% ) , low apgar ( 26.3% versus 10.5% ) , and adverse perinatal outcome ( 50% versus 21.1% ) were present , which was statistically significant ( table 3 ) .
in abnormal cp ratio group , sga ( 52.4% versus 29.3% ) , acidemia ( 23.8% versus 6.8% ) , low apgar ( 42.7% versus 9.5% ) , and perinatal outcome ( 61.9% versus 24.3% ) were present , which was also statistically significant .
this shows that both of these ratios are fairly accurate in predicting adverse neonatal outcomes .
table 4 shows overall performance of cu and cp ratio in predicting perinatal outcome . in the prediction of sga by cu ratio ,
the specificity was 67.7% , but negative predictive value ( npv ) was higher ( 73.7% ) . in prediction of poor apgar ,
the npv of the test was good with 89.5% , whereas the sensitivity and specificity was comparatively lower ( i.e. , 62.5% and 64.6% resp . ) .
even for the prediction of the need for assisted ventilation , the npv of the test was higher ( 80.7% ) . in 94.7% , if the cerebrouterine ratio was normal , less likelihood of acidemia was seen . in predicting overall adverse perinatal outcome , specificity was 70.3% and npv was 78.9% , with low sensitivity and positive predictive value . in the prediction of sga with cp ratio ,
the test had a good specificity of 84.8% and npv of 90.5% , in ruling out poor apgars .
in prediction of need for assisted respiration , specificity and npv were higher . in overall prediction of adverse perinatal outcomes ,
specificity was 87.5% and negative predictive value was 75.7% , indicating that if cp ratio is normal , the likelihood of adverse perinatal outcome is less .
table 5 shows perinatal outcome for four possible combinations of normal and abnormal cu and cp ratios .
it is interesting to note that when both ratios were normal , 76.9% had favorable outcome and when both were abnormal , 81.2% had adverse outcome .
thus it can be inferred that both ratios are complementary to each other in predicting perinatal outcome .
the prevalence of preeclampsia was more in primigravida in our study as is also seen in general .
nulliparous women are at increased risk , which is related to maternal first exposure to chorionic villi . in the present study ,
abnormal cu ratio was present in 38/95 ( 40% ) cases and abnormal cp ratio ( brain sparing ) was seen in 21/95 ( 22% ) cases .
the mean gestational age of delivery was comparable with that of a study done by as eser et al . which indicates that gestational age at delivery was significantly lower in group with abnormal cu ratio .
when cu ratio was abnormal , sga was present in 47.4% ( 18/38 ) babies and aga in 52.6% ( 20/38 ) babies .
thus , with the ratio being normal , the chance of sga was less likely .
simanaviciute and gudmundsson found significant correlation with sga newborn independently with abnormal cp ratio and bilateral uterine artery notching .
however , the abnormal cu ratio was not found to be associated with an sga in the newborn in their study .
the need of an assisted respiration such as continuous positive airway pressure ( cpap ) and ventilatory support was studied in relation to cu ratio .
those admitted to nicu with respiratory morbidity were seen in 31.6% ( 12/38 ) of babies .
when cu ratio was normal , 80.7% ( 46/57 ) did not require respiratory assistance .
there are no studies available in the current literature which have evaluated the correlation between cu and need for assisted respiration .
those with normal cu ratio 89.5% ( 51/57 ) had good apgars , indicating that normal cu ratio is reassuring .
simanaviciute and gudmundsson found no significant correlation between abnormal cu ratio and poor apgar score .
to study the overall outcome , modified tchirikov composite score for perinatal outcome was used .
preterm delivery was high in those patients with abnormal cu ratio . in cases of severe preeclampsia or imminent eclampsia , the threshold for caesarean delivery was also low . in 11 cases ,
absent end diastolic flow was noted , of which 2 cases also had severe olighydramnios .
pregnancy was terminated for both maternal and fetal causes , which led to premature delivery in preeclampsia cases .
thus , abnormal cu ratio could not be directly attributed to preterm delivery . in eser
study , cu ratio was independently associated with delivery before 37 weeks , whereas cp ratio was not . even with severe preeclampsia , some cases had normal cu ratio which can be due to the maternal intake of antihypertensive drug . in a study done by gnen et al . , treatment with methyldopa lowered the uterine artery resistance in preeclamptic patients but did not affect the resistance of umbilical and fetal middle cerebral artery .
, they did not find change in flow resistance of umbilical artery after administration of methyldopa [ 10 , 11 ] . in our study
cu ratio was abnormal in 17/44 ( 38.6% ) and normal in 27/44 ( 61.3% ) .
we found that sga , poor apgar scores , and preterm delivery rates were higher in the group with abnormal cu ratio than those with normal cu ratio , but poor outcomes were also seen in those with normal ratio , which indicates that there was not much change in fetal hemodynamic changes before and after treatment in cases of severe preeclampsia .
normalization of the doppler velocimetric indices of the fetal mca has also been reported in terminal cases [ 12 , 13 ] .
this could have also resulted in normal cu ratio in patients with severe preeclampsia , although the pathological changes would have already occurred .
the current study found that in the diagnosis of the complications of hypertension peculiar to pregnancy ( preeclampsia and gestational hypertension ) , cu ratio and cp ratio were complimentary to each other in predicting adverse perinatal outcomes than the independent ratios alone . | ### Summary:
: aims and objectives . (
i ) to determine the predictive value of cerebrouterine ( cu ) ratio ( middle cerebral artery to uterine artery pulsatility index , mca / ut pi ) in assessing perinatal outcome among hypertensive disorders of pregnancy .
( ii ) to compare between cu ratio and cp ratio ( mca / umbilical artery pi ) as a predictor of adverse perinatal outcome . methods . a prospective observational study was done in a tertiary medical college hospital , from september 2012 to august 2013 .
one hundred singleton pregnancies complicated by hypertension peculiar to pregnancy were enrolled .
both cu and cp ratios were estimated .
the perinatal outcomes were studied .
results .
both cerebrouterine and cerebroplacental ratios had a better negative predictive value in predicting adverse perinatal outcome .
however , both cu and cp ratios when applied together were able to predict adverse outcomes better than individual ratios .
the sensitivity , specificity , positive predictive value , and the negative predictive values for an adverse neonatal outcome with cu ratio were 61.3% , 70.3% , 56% , and 78.9% , respectively , compared to 42% , 57.5% , 62% , and 76% as with cp ratio .
conclusion .
cerebrouterine ratio and cerebroplacental ratio were complementary to each other in predicting the adverse perinatal outcomes .
individually , both ratios were reassuring for favorable perinatal outcome with high negative predictive value . |
<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:
: leishmaniasis represents a wide spectrum of clinical manifestations , ranging from a self - healing cutaneous lesion to fatal visceral disease .
it is estimated that 350 million people are at risk of leishmaniasis , 12 million are affected and the annual incidence is about 2 million ( 1 ) . in humans , cutaneous leishmaniasis ( cl ) caused by leishmania major is self - limiting and affected patient is resistant to reinfection .
this acquired immunity after natural infection or leishmanization suggests that an efficient vaccine is achievable .
but there are still no available vaccines against human cutaneous leishmaniasis ( 2 - 4 ) .
the main effect of particulate adjuvant / delivery systems is the effective delivery of antigen for enhanced uptake by antigen presenting cells ( apcs ) , and dendritic cells ( dcs ) in particular . these adjuvants are most often taken up by classical apcs , such as dcs and macrophages , whereas b cells are not the prime target for these delivery systems ( 5 ) .
various polymer- and lipid - based particulate antigen delivery systems have shown good potentials in potentiation of mucosal and systemic immune responses ( 6 , 7 ) .
sodium alginate , a natural polysaccharide polymer , can be easily cross - linked into a solid matrix with the addition of di- or trivalent cations ( cross - linking in a water - in - oil emulsion results in the formation of microspheres ) .
alginate microspheres were used in several studies and showed good potential as vaccine delivery system and immunoadjuvant ( 8 - 10 ) .
immunization of animals by alginate microspheres containing antigenic proteins elicited both humoral and cell - mediated immune responses ( 11 ) .
the immunoadjuvant effect of quillaja saponins ( qs ) , extracted from quillaja saponaria bark , is frequently reported ( 12 , 13 ) .
one proposed mechanism for immunoadjuvant effects of saponins is by formation of mixed - micelles with cell proteins ( 14 , 15 ) . controlling the cytokine production , clonal differentiation of complement cells in lymph nodes , enhancing the cytotoxic t lymphocytes ( ctl ) and natural killer cell activity , mitotic effect on lymphocytes and activation of macrophages and granulocytes
quil a , a purified fraction of quillaja saponaria extract , could intercalate into cell membranes through interaction with structurally similar cholesterol , forming holes or pores ( 18 ) .
this may allow antigen to gain access to the endogenous pathway of antigen presentation and promote a ctl response , however it is currently unknown if the adjuvant effect of saponins is related to pore formation ( 19 , 20 ) .
one advantage of particulate delivery systems is their potential for co - delivery of antigen and adjuvant to the same apc .
the immunogenicity of antigen and potency of an adjuvant could be substantially enhanced by their co - delivery in particulate delivery systems , like microspheres ( 21 ) . at the present study alginate microspheres encapsulated with autoclaved leishmania major ( alm ) and quillaja saponin adjuvant
materials , animals , parasite and sla
sodium alginate ( low viscosity grade ) and purified quillaja saponin were purchased from sigma ( st louis , mo , usa ) . autoclaved l. major ( alm ) produced at razi vaccine and serum research institute , hesarak , iran and used in clinical trials ( 3 , 22 - 25 ) .
female balb / c mice 6 - 8 weeks old were purchased from pasteur institute ?
the l. major strain ( mrho / ir/75/er ) used in this experiment is the same strain which has been used for preparation of experimental leishmania vaccine and leishmanization ( 3 , 22 - 27 ) .
soluble leishmania antigen ( sla ) was prepared from promastigotes of l. major harvested at log phase ( 28 ) , the protein concentration of sla was determined using lowry protein assay , and stored in small aliquots at -70c until use .
preparation and characterization of alginate microspheres encapsulated with alm and qs
methods of preparation and characterization of alginate microspheres used in this study has been reported in our previous publication ( 29 ) .
briefly , sodium alginate solution ( 3.0% w / v , low viscosity ) was dispersed in a n - octanol solution containing span-85 ( 2.0% w / v ) by sonication ( soniprep150 , mse , sussex , uk ) . in the case of alm and qs loaded microspheres , 3 mg of alm and 20 l qs ( 10 mg / ml in distilled water )
was rapidly added to a solution of calcium chloride in octanol ( 60 ml , 0.33% w / v ) while stirring on a magnetic stirrer .
after 10 min , 2 ml isopropyl alcohol was added dropwise to harden the formed microspheres .
the microspheres were collected by filtration , washed with isopropyl alcohol and finally dried in a vacuum desiccator .
immunization of balb / c mice
different groups of mice , 10 mice per group , were subcutaneously ( sc ) immunized ( 3 times at 3 weeks intervals ) using one of the following formulations : 1- alginate microspheres loaded with alm and qs ( alm+qs)alg ( 180 g alm + 10 g qs/10 mg microsphere/100 l pbs ) , 2- alginate microspheres loaded with alm and mixed with qs solution ( alm)alg+qs ( 180 g alm/10 mg microsphere + 10 g qs/100 l pbs ) , 3- alginate microspheres loaded with alm ( alm)alg ( 180 g alm /10
mg microsphere/100 l pbs ) , 4- alm solution mixed with qs solution , alm+qs ( 180 g alm + 10 g qs/100 l pbs ) , 5- alm solution , alm ( 180 g alm/100 l pbs ) , 6- pbs ( 100 l ) .
challenge with l. major
the immunized mice ( 7 per group ) were challenged sc into left footpad with 1.510
l. major promastigotes harvested at stationary phase ( in 50 l volume ) , at 3 weeks after the last booster and as a control right footpads were injected with the same volume of pbs .
lesion development was recorded in each mouse by measurement of footpad thickness using a metric caliper ( mitutoyo measuring instruments , japan ) .
grading of lesion size was carried out by subtracting the thickness of the uninfected contralateral footpad from that of the infected one ( 30 , 31 ) .
in - vitro spleen cell response
three mice from each group were sacrificed at week 3 after the last booster , at the same time as challenge experiment , the spleens were aseptically removed and a single - cell suspension was prepared by homogenization of the tissue , and the erythrocytes were disrupted using ammonium chloride .
the splenocytes were washed and resuspended in complete medium ( rpmi 1640-fcs ) and seeded at 210/ml in 96-well flat - bottom plates ( nunc ) .
the spleen cells were stimulated in vitro with sla ( 10 g / ml ) or con a ( 2.5 g / ml ) , or medium alone and incubated at 37 c in 5% co2 .
supernatants were collected at 72 h of culture and the concentration of il-4 and ifn- were titrated using elisa method according to the manufacturer s instructions ( 32 ) ( bender med systems gmbh , vienna , austria ) .
antibody isotype assay
blood samples were collected from the mice before and at week 14 after challenge and the sera were used to titrate anti - leishmania igg total , igg1 and igg2a antibodies using elisa method ( zymed laboratories inc .
briefly , 96-well microtiter plates ( nunc ) were coated with 50 l of 10 g / ml of sla overnight at 4 c. plates were washed and blocked with 1% bovine serum albumin in tween 20 ( pbs - tween ) .
optical density was determined at 450 nm using 630 nm as the reference wavelength ( 32 ) .
statistical analysis
one - way anova statistical test was used to assess the significance of the differences between various groups . in case of significant f
- value multiple comparison tukey test was used to compare the means of different treatment groups , p < 0.05 was considered to be statistically significant .
characterization of alginate microspheres
as reprted in our previous publication ( 29 ) the alginate microspheres used at the present study had a mean diameter of 1.92 1.0 m . the mean encapsulation efficiencies of alm and qs in microspheres were 34.2 6.7% and 31 4.2% .
alm was released from microspheres with a burst release of 9.1 3.0% after 30 min which was followed by a slow and continuous manner .
the release of qs was started with a burst effect of 7.3 1.9% after 30 min .
after 7 days of incubation , cumulative release of 36.9 4.7% was observed ( 29 ) .
lesion development after challenge
the protection against lesion development was monitored by weekly measurement of footpad thickness ( figure 1 ) .
the highest protection was seen in group of mice immunized with ( alm)alg+qs ( after 6 week , p<0.05 to p<0.0001 ) .
the least protection was seen in groups immunized with pbs , alm and ( alm+qs)alg .
footpad swelling in balb / c mice immunized sc , three times in 3 weeks intervals , with ( alm+qs)alg , ( alm)alg+qs , ( alm)alg , alm+qs , alm or pbs , after challenge with virulent l. major promastigotes .
( n = 7 ) .
in - vitro cytokine production by splenocytes
the supernatant of cultured splenocytes were used to titrate the level of ifn- and il-4 , cytokines indicative of th1 and th2 response , respectively .
the significantly ( p<0.01 ) highest levels of ifn- was seen in supernatant of splenocytes re - stimulated with sla , in groups of mice immunized with alm+qs and followed by ( alm)alg ( figure 2a ) .
the significantly ( p<0.01 ) highest level of il-4 was seen in supernatant of splenocytes re - stimulated with sla , in group of mice received alm+qs .
the il-4 titers seen in other groups were nearly identical and lower than the negative controls ( figure 2b ) .
splenic t - cell responses of balb / c mice immunized sc , three times in 3 weeks intervals , with ( alm+qs)alg , ( alm)alg+qs , ( alm)alg , alm+qs , alm or pbs .
twenty days after the last booster , their spleens were removed and the splenocytes were stimulated in vitro with either sla ( 5 g / ml ) or sla ( 10 g / ml ) , concanavalin a ( 2.5 g / ml ) , or with no stimulation .
production of ifn- ( a ) and il-4 ( b ) were assessed on culture supernatants collected at 72 h of in vitro incubation using sandwich elisa method .
each bar represents the mean and sem of triplicate wells in order to determine the type of immune response generated in immunized mice , the anti - sla specific igg , igg1 and igg2a antibodies were titrated before ( figure 3a ) and after ( figure 3b ) challenge with l. major promastigotes .
as shown in figure 3a , the significantly ( p<0.0001 ) highest titer of igg2a ( before challenge ) was seen in sera of mice immunized with qs - containing formulations .
the significantly ( p<0.0001 ) highest igg1 titer was seen in group of mice immunized with ( alm)alg or ( alm)alg+qs .
the ratio of igg2a / igg1 in sera of mice immunized with ( alm+qs)alg was significantly ( p < 0.05 ) higher than the other groups ( figure 3c )
. mice immunized with ( alm)alg showed the significantly ( p<0.0001 ) lowest igg2a / igg1 ratio . levels of anti - sla - specific igg , igg2a , and igg1 in sera of balb / c mice immunized sc , three times in 3 weeks intervals , with ( alm+qs)alg , ( alm)alg+qs , ( alm)alg , alm+qs , alm or pbs .
blood samples were collected from the mice , 3 weeks after the last booster ( a ) and 14 weeks after challenge ( b ) .
the sla - specific igg , igg2a and igg1 levels were assessed using elisa method .
values are the mean s.e.m challenge with l. major induced elevation of igg , igg1 and igg2a antibodies in all the groups of mice compared with the antibody titers before challenge ( figure 3a ) .
after challenge ( figure 3b ) , the significantly ( p<0.0001 ) highest igg2a titers were seen in group of mice received alm .
the significantly ( p<0.001 ) highest igg2a / igg1 ratio was seen in mice immunized with alm and followed by qs - containing formulations ( figure 3c ) .
to enhance the immunogenicity of alm , alginate microspheres encapsulated with alm alone or alm + qs were used to immunize mice .
the protection rate , the extent and the type of immune response were evaluated in susceptible balb / c mice .
qs as an immunomodulator adjuvant was co - administered with alm , both mixed or co - encapsulated .
the protection induced with alm+qs was more than alm group ( figure 1 ) , but differences were not significant .
/ igg1 ratio compared to the group received alm alone was not significantly different ( p>0.05 ) . in phagocytosis of particulate antigen delivery systems ,
macrophages and dendritic cells could directly phagocyte the particles smaller than 10 m in diameter ( 33 ) . at the present study alginate microspheres with the mean diameter of 1.92 1.0 m which are readily phagocytosed by macrophages
particulate antigens facilitate interaction with antigen presenting cells and induce stronger immune response compared to the soluble antigens ( 15 , 34 ) . as release profiles showed , within one week of release study , about 30% of antigen and adjuvant released from the microspheres .
. in murine model of leishmaniasis , recovery and protection depends upon generation of th1 type of response , and progression of disease relates to the induction of th2 type of response .
the key cytokine and antibody subtype indicative for th1 response are ifn- and igg2a , while il-4 and igg1are key indicators of th2 response ( 21 , 35 ) .
alginate microspheres encapsulated with alm induced a higher igg1 and a lower igg2a titers and a lower igg2a / igg1 ratio , as compared with free alm .
antibody titers indicate that encapsulation of alm in alginate microspheres skews the immune response toward a th2 response . however , the level of ifn- in group of mice immunized with ( alm)alg was significantly ( p<0.01 ) higher than the group received alm alone , which is contrary to the antibody titers .
after challenge with l. major promastigotes the lesion size was significantly smaller in group of mice received in ( alm)alg than the group received alm alone ( p<0.05 , after 4 weeks ) , therefore , the microspheric formulations showed to induce a higher protection . thus
while the antibody titers are against the microspheric formulation , the cytokine titers and the lesion size showed a positive potential for microspheres in induction of protection in murine model of leishmaniasis , compared with animals immunized with alm alone . in our previous studies in rabbit , tetanus toxoid ( tt ) as a model antigen
the igg , siga , and antitoxin titers induced with ( tt)alg were significantly ( p<0.01 ) higher than the tt solution . the alginate microspheres were also mixed with qs solution . the protection induced by ( alm)alg+qs was significantly higher than ( alm)alg ( after 6 week , p<0.05 to p<0.0001).the ( alm)alg+qs could induce higher igg2a / igg1 ratio and lower ifn- levels , compared with ( alm)alg group ( p<0.0001 ) .
co - encapsulation of qs with alm in the microspheres ( ( alm+qs)alg ) had a negative effect on protection . in mice immunized with ( alm+qs)alg , the igg2a / igg1 ratio was higher ( p<0.0001 ) than ( alm)alg+qs , however , the lesion size was more than ( alm)alg+qs group ( p<0.0001 ) .
several authors have shown that quillaja saponins ( including qs-21 ) stimulated the production of ctls and induces th1 cytokines ( il-2 and ifn- ) and antibodies of the igg2a isotype to protein antigens ( 36 , 37 ) .
the potential of quil a in induction of th1 immune responses against murine visceral leishmaniasis was demonstrated in their combination with the fucose
it was shown that the qs-21/fml and quil a / fml groups achieved the highest igg2a response , while quil a / fml developed the strongest delayed type of hypersensitivity ( dth ) and qs-21/fml animals showed the highest serum ifn- concentrations among five kinds of adjuvants ( 38 ) .
quil a or qs-21 could also elicit antigen - specific th1 responses against plasmodium falciparum , foot - and mouth disease and measles virus in mice ( 38 ) . in the other hand , these are several studies in which a mixed th1 and th2 immune responses have been reported for saponin adjuvants .
saponins have been found to enhance phagocytosis and stimulate secretion of cytokine such as il-1 , il-2 , il-4 , il-6 , il-10 , ifn- and tnf-
. such broad range of cytokines is consistent with the mixed th1/th2 responses ( 39 ) .
injection in mice , pgs showed a balanced th1 and th2 immunological response ( 40 ) .
for the immunotherapy of dogs , when quil a was added to leishmune vaccine , average of the clinical scores was decreased , but average of cd4 + leishmania - specific lymphocytes was increased ( 41 ) .
p. notoginseng saponin elicited a th1 and th2 immune response in mice by regulating production and gene expression of th1 and th2 cytokines ( 42 ) .
the type of immune response that is reported after immunization of saponin - adjuvanted vaccines ( th1 or mixed th1/th2 ) depends not only on the adjuvant itself , but also on the factors like the antigen , administration route and immunization schedule ( 39 ) .
the other explanation for different immune responses is related to lipophilic acyl side chain of saponins which is shown to be responsible for the remarkable stimuli for ctl production against exogenous proteins and instability under physiological conditions ( 43 ) .
the spontaneous deacylation of saponins in aqueous solution ( 44 ) , could lead to production of the deacylated saponins .
these deacetylated saponins are significantly less toxic and elicit th2 responses while fail to stimulate either a lymphoproliferative response or the formation of ctl ( 43 ) .
in summary the results of this study showed that qs adjuvant induced a mixed th1/th2 immune response . | ### Summary:
: leishmania antigens are weak immunogens and need to be potentiated by various adjuvants and delivery systems .
alginate microspheres as antigen delivery system and quillaja saponins ( qs ) as immunoadjuvant have been used to enhance the immune response against autoclaved leishmania major ( alm ) .
microspheres were prepared by an emulsification technique and characterized for size , encapsulation efficiency and release profile of encapsulates .
balb / c mice were immunized three times in 3-weeks intervals using alm plus qs loaded microspheres [ ( alm+qs)alg ] , alm encapsulated with alginate microspheres [ ( alm)alg ] , ( alm)alg + qs , alm + qs , alm alone or pbs . the intensity of infection induced by l. major challenge was assessed by measuring size of footpad swelling .
the strongest protection , showed by significantly ( p < 0.05 ) smaller footpad , were observed in mice immunized with ( alm)alg+qs . the ( alm+qs)alg , alm and pbs groups showed the least protection and highest swelling , while the ( alm)alg and alm+qs showed an intermediate protection with no significant difference .
the mice immunized with ( alm+qs)alg showed the highest igg2a / igg1 ratio ( p<0.05 ) . the highest ifn- and il-4 production was seen in alm+qs ( p<0.01 ) . it is concluded that qs adjuvant has a mixed th1/th2 effect and has increased both humoral and cellular immune responses . |
<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:
: acute eosinophilic myopericarditis ( aem ) is a rare disorder of unknown etiology , which is characterized by diffuse or focal myocardial inflammation with eosinophilic infiltration .
it frequently results in cardiogenic shock and a fatal clinical course if diagnosis is delayed .
because it usually dramatically responds to steroid therapy , early diagnosis and treatment possibly reduce the mortality and morbidity in aem ( 1 , 2 ) . here we report the case of early diagnosis of aem by cardiovascular magnetic resonance ( cmr ) before pathologic report .
a 35-yr - old woman presented to the emergency department on april 30 , 2010 with flu - like illness and malaise for 3 days , followed by pleuritic chest pain and shortness of breath .
her heart rate was 80 beats / min and a blood pressure of 90/70 mmhg .
laboratory values reveals : white blood cells 12,030/l ( normal range , 4,500 - 10,000/l ) ; absolute eosinophil count 1,624/l ( normal range , 50 - 350/l ) ; creatinine kinase 72 u / l ( normal range , 24 - 173 u / l ) ; creatinine kinase mb 3.96 u / l ( normal range , < 5 u / l ) ; troponin 1.343 ng / ml ( normal range , < 0.78 ng / ml ) ; n - terminal probnp : 3,465 pg / ml ( normal range , < 150 pg / ml ) ; erythrocyte sedimentation rate 3 mm / hr ( normal range , < 27 mm / hr ) ; and c - reactive protein 0.71 mg / dl ( normal range , < 0.3 mg / dl ) .
the electrocardiogram showed sinus rhythm with nonspecific st - segment and t - wave abnormalities and the chest radiography was normal .
the transthoracic echocardiography showed borderline left ventricular ( lv ) systolic dysfunction with slightly increased lv wall thickness ( lv interventricular septum , 11 mm ; lv posterior wall , 11 mm at end diastole ) and small amount of pericardial effusion ( fig .
cmr was performed with the protocol of cine image , t2 weighted image , and delayed gadolinium - enhanced imaging with phase - sensitive inversion recovery ( psir ) technique after injection of 0.15 mm / kg gadovist ( gadobutrol ; bayer schering pharma , berlin , germany ) using an 1.5-t scanner ( magnetom avanto , syngo mr b15 version ; siemens medical solutions , erlangen , germany ) .
cine image showed borderline lv systolic function ( lv ef = 51% ) with slightly increased lv wall thickness ( 11 mm at diastole ) , same as echocardiography .
elevation of t2 signal intensity was found in whole lv myocardium and basal posterior side of pericardium and diffuse delayed hyper - enhancement especially in the lv septum , anterior and anteriolateral wall and moderate pericardial effusion ( fig .
2 ) . the presumptive diagnosis based on the clinical feature and cmr findings was aem .
steroid therapy was initiated with oral prednisone at 1 mg / kg / day . after being started on steroid therapy , her peripheral eosinophilia resolved and her symptoms improved from hospital day 1 .
although , clinical course and cmr showed high probability of aem , we performed endomyocardial biopsy 2 days later after initiation of steroid therapy ; because until now , it is a golden standard for diagnosis of myocarditis .
follow up echocardiogram 3 days after initiation of steroid therapy showed improvement in systolic function , normalization of lv wall thickness and decreased pericardial effusion .
after 2 months , follow - up cmr showed absence of pericardial effusion , and high signal intensity in t2 image , and no abnormal lge in parallel with clinical improvement ( fig .
however , it is invasive procedure and takes several hours to days to confirm the results .
furthermore , it is not a very sensitive technique because the infiltrates in aem are often focal ( estimated sensitivity at 50% ) ( 3 ) .
recently , cmr is frequently used as a supportive diagnostic tool in suspected acute myocarditis in clinical decision making .
cmr can visualize the inflammation and tissue edema in entire myocardium , which is ideal for a disease with patchy involvement of myocardium such as myocarditis , and the course of aem during treatment ( 4 ) .
cmr using t1-weighted early gadolinium enhancement , t2-weighted edema imaging , and lge imaging using appropriate pulse sequences were reported as sensitive methods to detect changes in tissue composition .
abdel - aty et al . ( 5 ) reported that higher t1-weighted early gadolinium enhancement had a sensitivity of 80% and specificity of 73% in diagnosis of the patients with myocarditis .
they also found that increased t2 signal intensity had a sensitivity of 84% and specificity of 74% and lge in subepicardial myocardium had a sensitivity of 44% and specificity of 100% .
when t2-weighted cmr is combined with gadolinium enhancement imaging , it had a high diagnostic accuracy in patients with suspected acute myocarditis ( 6 ) .
lge pattern of myocarditis is characterized by diffuse enhancement of myocardium . according to the clinical course , diffuse enhancement changes into patch involvement , and remains scar in some patients . in myocarditis patients ,
cardiac enzyme usually elevated and differential diagnosis of acute myocardial infarction is crucial for management of patients .
lge in acute myocardial infarction is characterized by subendocardial involvement of lge according to the coronary artery disease , and easily discriminates myocarditis from acute myocardial infarction with high sensitivity and specificity . in case of cardiac amyloidosis ,
diffuse lge pattern may be found , however t2 signal usually does not increase ( 7 ) .
our patient with peripheral eosinophilia , immediately underwent cmr before cardiac biopsy suggested findings of acute myopericarditis .
early high dose corticosteroids therapy leads to dramatic improvement before the pathologic diagnosis of aem .
after 2 months of steroid therapy , follow - up cmr revealed no residual delayed hyperenhancement suggesting favorable clinical outcome without any residual pathology in myocardium .
this presentation emphasizes on the role of cmr which enables early non - invasive diagnosis of aem and visualize the extent of the myocarditis . | ### Summary:
: we report a case of early non - invasive diagnosis of acute eosinophilic myopericarditis ( aem ) by cardiovascular magnetic resonance ( cmr ) before cardiac biopsy . a 35-yr - old woman presented with a flu - like illness , followed by pleuritic chest pain and shortness of breath .
transthoracic echocardiography revealed mild left ventricular ( lv ) systolic dysfunction with borderline lv wall thickness and moderate pericardial effusion .
the patient had peripheral eosinophilia and cmr was performed immediately at first day of visit before cardiac biopsy .
cmr showed diffuse subepicardial high t2 signals and diffuse late gadolinium enhancement in lv .
steroid therapy was immediately initiated and patient 's symptom was rapidly improved .
endomyocardial biopsy at hospital day 3 reported multifocal mild infiltration of eosinophils and lymphocytes .
the patient was finally confirmed as acute eosinophilic myopericarditis .
this presentation emphasizes on the role of cmr which enables early non - invasive diagnosis of aem and visualize the extent of the myocarditis . |
<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:
: chronic myeloid leukemia ( cml ) is a myeloproliferative disorder that results from the reciprocal translocation of the abl1 oncogene on chromosome 9 with the breakpoint cluster region ( bcr ) gene on chromosome 22 [ t(9 ; 22 ) ] , leading to the formation of the bcr - abl oncoprotein .
the shortened chromosome 22 formed by this translocation is the philadelphia ( ph ) chromosome .
the bcr - abl fusion oncogene , which is responsible for the pathogenesis of cml , has greatly enhanced abl1 tyrosine kinase constitutive activity .
most patients are diagnosed in the chronic phase ( cml - cp ) , which is characterized by the absence of symptoms in half of the patients . however , a prominent leukocytosis is frequently observed by routine testing . in the other half of patients , symptoms are common and include splenomegaly , weight loss , lethargy , and anemia .
the disease may progress either directly to blast phase ( bp ) or through an intermediate accelerated phase ( ap ) .
the time course for progression to bp is variable and the molecular mechanisms underlying disease progression are extremely complex .
bcr - abl - dependent pathways to blast transformation include an increase in genomic instability , telomere shortening , loss of tumor - suppressor function , and inhibition of tumor suppressors with cell regulatory functions [ 2 , 3 ] . in order to identify prognostic factors for cml patients ,
sokal risk score ( based on spleen size , age , platelet count , and peripheral blood blast ) is a prognostic factor widely used for prediction of cytogenetic response and of progression - free and overall survival in cml - cp with imatinib as front - line therapy .
other factor predictors for therapy response include oct-1 activity , abcb1/p - glycoprotein overexpression and polymorphisms , in vivo measurement of the crkl phosphorylation , and molecular response .
the treatment of cml - cp can be divided into pre - imatinib and post - imatinib era .
prior to the imatinib era , busulphan and interferon- recombinant [ 5 , 6 ] were used to control and to prolong cml survival in the cp phase , but allogenic stem - cell transplantation was , and is still , the only therapy with potential for curing cml patients .
after the introduction of imatinib , a potent tyrosine kinase inhibitor ( tki ) , there was a dramatic change in the cml outcome .
imatinib acts by binding to the bcr - abl protein in the inactive conformation and is unable to bind to the active configuration .
the survival rate attributed to imatinib is arguably more elevated than interferon - based therapy .
imatinib treatment is associated with high rates of complete cytogenetic and major molecular responses in patients with cml - cp . on the other hand , despite improvements related to survival by using imatinib or other tkis , cml - bp prognosis remains disappointing .
currently , imatinib is the standard therapy for all cml phases [ 1214 ] . despite the clinical success with imatinib demonstrating long - term survival for the majority of patients , one - third of
patients need an alternative therapy , frequently a second - generation tki , such as dasatinib and nilotinib .
patients who need second - line therapy include those with imatinib intolerance or mainly primary or acquired imatinib resistance [ 15 , 16 ] .
the most common mechanism of resistance to imatinib is the development of point mutations or amplification of the bcr - abl gene , which alters the kinase domain ( kd ) of bcr - abl and is responsible for imatinib loss of efficacy .
bcr - abl acts with other multiple cellular and genetic events that accumulate progressively to drive the disease into the blast phase .
therefore , additional mechanisms dependent or independent to bcr - abl may also account for resistance to imatinib treatment and result in a poor outcome . in this review ,
the role of efflux and influx transporters , inhibitor of apoptosis proteins ( iap ) , and transcription factors as additional mechanisms responsible for chemoresistance in cml will be discussed .
the multidrug resistance ( mdr ) phenotype related to increased expression of efflux pumps , such as abcb1/p - glycoprotein ( pgp ) and abcg2/breast - cancer - related protein ( bcrp ) , is one of the most studied mechanisms of resistance in cml .
more recently , the decrease in influx transporters , such as the organic cation transporter-1 ( oct-1 ) , has also emerged as a mechanism responsible for inefficient drug uptake and consequent treatment failure [ 16 , 19 ] .
the most common mechanism developed by tumor cells to escape a drug - induced death is displayed in intrinsic or acquired mdr phenotype by the overexpression of the drug - efflux protein abcb1 [ 20 , 21 ] .
abcb1 , a product of the abcb1 gene , was first described in 1976 by juliano and ling , who observed a cell surface glycoprotein that altered drug permeability in hamster drug - resistant cells .
human cells also express abcb1 on the cell surface , acting as a drug efflux pump and , consequently , decreasing intracellular drug concentration [ 22 , 23 ] .
meanwhile , physiological abcb1 expression has been identified in some tissues , particularly on the membranes of kidney tubules , in the canalicular membranes of hepatocytes , in the gastrointestinal tract , at blood tissue barriers , in the placenta , and in blood cells including cd34 hematopoietic stem cells , natural killer cells , antigen - presenting dendritic cells ( dc ) , and t and b lymphocytes [ 2428 ] .
its physiological function suggests a protection against potentially toxic compounds and harmful substances found in the blood stream .
studies on abcb1 knockout mice showed no physiological abnormalities under normal conditions , although these animals display hypersensitivity to drugs and an increase in abcb1 substrate accumulation [ 27 , 2931 ] .
clinical insensitivity to anticancer agents is mainly attributed to an elevated expression of abcb1 , which is related to treatment failure associated with lower remission and survival rates in some types of cancer , including leukemias [ 3234 ] . meanwhile , gene and protein expressions of abcb1 are commonly acquired or increased during the course of chemotherapy , which make drug treatment a responsible factor for mdr [ 35 , 36 ] .
levchenko et al . showed that abcb1 , and , consequently , mdr are transferred by direct membrane contact of tumor cells .
the shared microparticles can bind to receptor cells , spread abcb1 and , consequently , induce mdr phenotype . even though the abcb1 efflux functions , other functions for this transporter have been studied .
studies have shown that the resistance induced by abcb1 is also associated with the inhibition of cell death , and abcb1 promotes additional protection to caspases - dependent apoptosis , uv radiation , serum starvation condition , and spontaneous apoptosis [ 3942 ] .
recently , our group demonstrated that abcb1 expression induced by drug treatment promotes resistance to apoptosis in bcr - abl cells independently of its drug - efflux activity .
abcb1 is related to resistance phenotype in some leukemias and it has been studied in advanced cml .
the authors observed that the response to cytarabine and daunorubicin was significantly related with both abcb1 expression and function mainly in the blast phase .
for this reason , chemotherapy resistance in cml - bp patients should be considered multifactorial and can not be associated only with bcr - abl [ 4447 ] .
our group recently demonstrated that cml patients show high levels of abcb1 expression independently of cml phases .
nevertheless , we showed that abcb1 expression is more frequent than multidrug - resistant protein 1 ( mrp1 ) in cml - bp .
in vitro data
suggest that imatinib is able to induce abcb1 in sensitive cml cell lines and , as a result , abcb1 activity may confer resistance to this drug [ 4951 ] .
mahon et al . demonstrated that a multidrug - resistant cml cell line displayed resistance to many drugs including imatinib and the induced overexpression of abcb1 gene by retroviral transduction in bcr - abl cell line also leads to imatinib resistance .
, showed that a stable silencing of abcb1 in imatinib - resistant cml cell lines abolished abcb1-efflux substrates and induced sensibility to imatinib . regardless of the in vitro data
, there is no consistent evidence for this resistance in vivo , although several studies have discussed the role of abcb1 in imatinib - resistant cml patients .
zong et al . demonstrated that bone marrow mice cells mdr1a/1b - null transduced with bcr - abl display a similar response to imatinib , which is related to increased peripheral white blood cells counts and marked hepatosplenomegaly , compared with bcr - abl - transduced wild - type bone marrow .
the authors concluded that the expression of abcb1 in hematopoietic stem cells does not interfere with imatinib resistance .
another in vivo study revealed that imatinib treatment in cml patients in the accelerated phase induced an increase of abcb1-positive cells with efflux activity .
however , in imatinib - resistant cml patients , the efflux activity was independent of abcb1 expression , suggesting participation of other abc transporters .
inhibited abcb1 using psc833 in cd34 cells from cml - cp patients and did not observe imatinib efficiency in eliminating cml cells .
although these previously described works do not identify the role of abcb1 in imatinib resistance , studies in polymorphisms of abcb1 have shown the importance of abcb1 in cml treatment resistance .
moreover , this kind of study may provide information for the prediction of drug disposition in a specific way and promote better response to imatinib in cml patients [ 58 , 59 ] .
analyzed 1236c > t , 2677g > t / a , and 3435c > t abcb1 single nucleotide polymorphisms ( snps ) in cml patients treated with imatinib .
the authors observed that allele g in 2677g > t / a polymorphism was associated with the worst response to imatinib . in a chinese population ,
ni et al . observed more imatinib resistance in patients homozygous for 1236 t allele and 3435 tt / ct genotypes .
studies have suggested that second- and third - generation tkis can overcome imatinib resistance [ 62 , 63 ] .
there are studies suggesting that nilotinib does not induce resistance in cml cells through abcb1 overexpression .
developed nilotinib - resistant cml cell lines and observed that nilotinib is a substrate for abcb1 . moreover
, concomitant overexpression of abcb1 and bcr - abl provides nilotinib resistance in cml cells .
giannoudis et al . showed that cell lines bcr - abl ( positive or not ) are able to extrude dasatinib through abcb1 activity .
these studies show the importance of researching more about abcb1 expression , function , and inhibition .
the cyclosporine a ( csa ) is capable of regulating the efflux function of abcb1 dependently on its concentration in cancer cells [ 68 , 69 ] .
some studies in hematological cancer have shown the benefits of csa on reversing mdr or potentiating drug effects . in a clinical study of our group
, we evaluated the effect of csa on the circumvention of leukemia patients mdr in vitro .
our data showed that combination of csa and etoposide ( vp-16 ) could induce a good response in abcb1-positive cml patients .
in the same year , we also published a case report showing that the cytotoxic effect of vp-16 was enhanced in combination with csa in blast cells of cml .
another important efflux pump associated with chemotherapy resistance in cml is bcrp or abcg2 , coded by the gene abcg2 .
it has an n - terminal atp - binding domain ( nbf ) and a c - terminal transmembrane domain ( tmd ) , a structure half the size and in reverse configuration to most other abc proteins comprising two nbfs and two tmds .
because abcg2 is a half - transporter , it is believed to homodimerize , or possibly oligomerize , in order to function .
fetsch et al . , reported high levels of abcg2 expression in normal placenta , interstitial cells of testes , endocervical cells of uterus , squamous epithelium of cervix , kidney , hepatocytes , pancreas , and small and large intestinal mucosa / epithelial cells .
other chemotherapeutic substrates include flavopiridol , topotecan , methotrexate , and the tkis imatinib , gefitinib , and erlotinib .
if the amino acid at position 482 is mutated , mitoxantrone transport is more efficient and abcg2 can additionally transport rhodamine 123 and anthracyclines such as doxorubicin and bisantrene [ 77 , 78 ] .
it was demonstrated that tki had high - affinity interaction with abcg2 and that it occurs at submicromolar concentrations [ 79 , 80 ] .
although other tkis promote atpase activity , imatinib was the only one able to inhibit it , suggesting that this drug acts as a modulator agent .
in addition , imatinib has promoted the accumulation of a fluorescent substrate inside the cells which reinforced its role as a modulator . using a different methodology , houghton et al
. demonstrated that overexpression of abcg2 was not able to confer resistance to imatinib , suggesting that it is not a substrate for this transporter .
in addition , imatinib promoted the accumulation of topotecan in functional abcg2-expressing cell lines , indicating a role of imatinib as a modulator but not as a competitor .
conversely , ko-143 , an abcg2 specific modulator , could increase the imatinib accumulation in abcg2-overexpressing cell lines , suggesting its role as a competitor .
interestingly , mitoxantrone accumulation in the same cell lines was increased by the addition of imatinib , suggesting its role as a modulator .
furthermore , brendel et al . confirmed that abcg2 expression confers imatinib resistance and reduces imatinib accumulation in k562 cells , effects that are abrogated by the abcg2 inhibitor fumitremorgin c ( ftc ) .
more importantly they observed that differences on imatinib accumulation were only seen when imatinib was used at low concentrations but not at high concentrations .
these data support the idea that imatinib may act as a modulator or a substrate depending on the concentration level . however , there is still no consensus on whether imatinib is a substrate or a modulator of abcg2 transport .
regardless of its role as a substrate or modulator , imatinib interacts with abcg2 , which may have their effectiveness limited by the overexpression of this protein .
it is believed that cml is a clonal disorder originating from the hematopoietic stem cell ( hsc ) .
. demonstrated that primitive hscs expressing bcr - abl in cml - cp patients were resistant to imatinib .
this discovery led to the hypothesis that the resistant population could contribute to the failure of treatment with imatinib .
studied the interaction of abcg2 and imatinib on a cell line expressing bcr - abl .
this cell line was resistant to substrates of abcg2 as well as imatinib , and the resistance was reversed by inhibiting abcg2 .
another interesting finding was that the initial resistance to imatinib caused by abcg2 was attenuated by the inhibition of bcr - abl , suggesting that bcr - abl regulates the expression of abcg2 at a later stage of transcription .
some authors have identified the presence of abcg2 in a particular group of hsc called side population ( sp ) due to its efflux of the fluorochrome hoechst 33342 and its ability to reconstitute bone marrow in irradiated mice .
afterward , it was demonstrated that abcg2 was responsible for the sp in mouse and human bone marrow [ 87 , 88 ] .
abcg2-deficient mice are viable with normal numbers of stem cells . despite the absence of sp
however , abcg2 may play a protective role for stem cells , because zhou et al . demonstrated that stem cells derived from abcg2-deficient mice were more sensitive to cytotoxic substrates .
once abcg2 is expressed in the apical membrane of cells in the epithelium of the small intestine and colon , it is very likely that abcg2 is involved in the active return of drug entering the intestine .
this role would be important in reducing the systemic bioavailability of oral drugs such as imatinib .
studies in abcg2 knockout mice indicate that abcg2 and abcb1 appear to regulate the penetration of imatinib into the brain tissue .
the snp 421c > a is responsible for decreased plasma membrane expression of abcg2 , reduced atpase activity , or decreased drug transport [ 9294 ] .
therefore , the daily imatinib dose for patients with the abcg2 421c / c genotype might be higher than for those with the 421c / a or 421a / a genotype .
knowledge of the abcg2 421 genotype could be useful when making dosing decisions aimed at achieving the optimal imatinib exposure .
members of the solute carriers ( slcs ) superfamily of transporters are known as passive facilitator carriers that allow the passage of solute through the membrane without spending energy .
this superfamily is divided into 43 families according to the type of substrate transported and the type of transport .
some families carry specific substrates such as oligopeptides , sugars , phosphatases , or metals , whereas other families are polyspecific , transporting substrates with different sizes and structures .
slc transporters are mostly expressed in the plasma membrane and play a critical role in a variety of physiological cellular processes such as import / export neurotransmitters , nutrients , or metabolites .
the family 22 of solute carrier proteins is composed of 12 members mostly of poly - specific transporters .
many members of this family are expressed in the intestine , liver , and kidney , indicating an important role in the absorption and excretion of drugs , xenobiotics , and endogenous compounds that exist as cations at physiological ph .
the family is further divided into subgroups according to the substrate and the transport mechanism .
a growing number of scientific papers have shown that some chemotherapeutics are substrates for influx transporters .
recently , it was reported that imatinib is transported into the cell , preferably via slc22a1 ( also called oct-1 ) , and the expression of this transporter is predictive of achieving a complete cytogenetic remission after 6 months of treatment with imatinib .
it was reported that the influx of imatinib is temperature dependent , indicating the involvement of an active process of influence .
when the cells were incubated with inhibitors of the transporter slc22a1 , the influx of imatinib was significantly reduced . since then
, other studies have been published supporting the hypothesis that imatinib is a substrate for the transporter slc22a1 .
white et al . analyzed the activity of slc22a1 in samples from cml patients before starting treatment with imatinib and compared this with getting a major molecular response at 24 months . in this study , the activity of slc22a1 was an important determinant of molecular response to imatinib with strong predictive value on the dose .
the analysis of slc22a1 activity before the start of treatment with imatinib was able to identify patients who would need a higher dose of the drug to respond to medical treatment with imatinib .
besides the slc22a1 activity , the levels of expression of slc22a1 may be related to a decreased influx of imatinib .
crossman et al . analyzed the expression of the slc22a1 gene in samples from cml patients before starting treatment and observed that the expression of slc22a1 was variable and did not differ significantly from levels found in samples of bone marrow healthy individuals .
however , patients who responded to treatment with imatinib had significantly higher levels of expression of the slc22a1 gene as compared to the group of nonresponders . despite this and other articles suggesting a direct correlation between slc22a1 and response to treatment with imatinib , hu et al
. believe that slc22a1 per se is not able to influence the retention of imatinib , as this drug would be a poor substrate for slc22a1 . on the other hand , wang et al . suggested that clinical responses to imatinib could be affected by transporters slc22a1 , abcb1 , and abcg2 .
patients with high pretreatment slc22a1 expression had a higher probability of achieving a cytogenetic response and a superior progression - free and overall survival .
the contribution of the slc22a1 transporter to the clinical response to imatinib has not yet been elucidated .
therefore , further studies are needed to evaluate the role of this influx transporter in the clinical outcome of imatinib treatment .
the iap family members are characterized by a common baculoviral iap repeat ( bir ) domain and by the ability to block apoptosis through the inhibition of both mitochondrial - dependent and -independent apoptotic pathways [ 104 , 105 ] . among iaps
, much attention has been focused on survivin and xiap due to their potential role as therapeutic targets .
xiap ( x - linked of inhibitor of apoptosis protein ) is a singular iap because it is the only member of the family known to directly inhibit caspases-3 , -7 , and -9 [ 106 , 107 ] .
xiap is able to bind their target caspases by a two - site interaction mechanism , which inhibits the apoptotic pathway by blocking the active caspase site or by dissociating the dimer of caspases .
there are at least two proteins , smac / diablo and xaf1 ( xiap - associated factor 1 ) , known to interact with xiap and modulate its antiapoptotic activity , which suggests a significant role of xiap in the maintenance of the cellular homeostasis .
other relevant xiap properties are the involvement in copper metabolism and the capacity of self - ubiquitination and of other targets involved or not in the control of the cell death , demonstrating its versatility in the cellular physiologic processes .
studies using knockout murine models for xiap ( xiap / birc4 ) showed that its absence does not alter caspases - dependent or -independent apoptosis , but increases the expression of other iaps , possibly as a compensatory mechanism .
xiap is widely expressed in normal tissues ; however , its overexpression in cancer is usually associated with an unfavorable prognosis [ 116119 ] . although it has been demonstrated that the nuclear localization of xiap is an independent prognostic marker in breast cancer , little is known about the expression and subcellular localization relevance of xiap in cml patient samples .
increasing evidence demonstrates that treatment of cml cells with chemotherapeutic agents can overcome resistance through negatively regulating xiap levels .
fang et al . have observed that one of the mechanisms involved in bcr - abl - positive cells sensitivity to imatinib is xiap downregulation . corroborating this data , a study conducted in k562 cells and leukemic blasts obtained from patients with cml in blast crisis showed that apicidin , a histone deacetylase inhibitor , was able to potentiate imatinib effects on apoptosis through xiap degradation and the release of the proapoptotic protein smac / diablo into cytosol .
these events were associated with reduced bcr - abl protein expression and decreased phosphorylated akt levels and were caspase dependent .
imatinib - induced apoptosis could also be potentiated when coadministered with abt-737 , a bcl-2 and bcl - xl inhibitor .
cotreatment of k562 cells and primary cml samples led to caspase-3 activation and htra2/omi - mediated decreased xiap levels both in k562 cells and tki - insensitive cml hematopoietic progenitors .
in addition to these findings , treatment of k562 cells with trail led to an apoptosis - resistant phenotype through the upregulation of antiapoptotic proteins , including xiap , further emphasizing its role in chemoresistance in cml .
many strategies have been used to inhibit both the expression and function of xiap and resensitize cancer cells to different cytotoxic stimuli [ 125127 ] .
one study demonstrated that the downregulation of xiap expression using antisense oligonucleotides increased the sensitivity to cytotoxic stimuli , inducing apoptosis and decreasing cell viability in the k562 cell line .
recently , the same group showed that the simultaneous inhibition of xiap and p - glycoprotein in cells that overexpress this efflux pump decreases imatinib resistance .
consistent with this , a recent work published by our group found that cyclosporine - a - mediated pgp modulation was associated with xiap inhibition and an increased apoptotic index as a response of resistant cml cells to vincristine .
altogether , these findings point xiap as an interesting therapeutic target and suggest that combining chemotherapeutic agents with xiap - targeted therapy seems to represent a promising strategy in cml .
survivin , another iap member , is an antiapoptotic protein , which also regulates cell division by controlling mitotic spindle checkpoint .
survivin gene generates five different splice variant mrnas , which encodes different proteins : wild - type survivin , survivin-2b , survivin-3b , survivin-ex3 , and survivin-2 .
compared to wild - type survivin , little prognostic information is known about the functions of alternative splicing forms , which are generally expressed at lower levels than the wild - type survivin . in a recent study
, it was found that patients in blast and accelerated phases displayed significantly lower levels of survivin-2b and -ex3 , compared to patients in cml - cp . however , there was no correlation between the isoform expression and clinical parameters or response to imatinib treatment .
undetectable in normal differentiated tissues , survivin is abundantly expressed in all the most common human cancers [ 131 , 135 ] , which makes this protein a potential target for drug discovery and new anticancer interventions .
survivin can also be found in normal tissues characterized by self - renewal and proliferation , but its expression is significantly lower than in tumor cells . in cd34 hematopoietic progenitor stem cells , survivin was found to be expressed and associated with the inhibition of apoptosis .
however , a recent report showed that despite survivin being quite expressed in cd34 cells , its levels are low in more precursor leukemia stem cells , indicating that survivin is not an optimal therapeutic target for cml stem cells compartment and suggesting that it may not be the main factor accounting for resistance to targeted therapy in cml . in cml patient samples ,
several studies have reported that survivin was expressed in the accelerated and blast phases but it was low or undetectable in the chronic phase [ 4 , 140143 ] , suggesting that survivin may be involved in the pathogenesis of progression from the cml - cp to the cml - bp .
in addition , survivin overexpression in cml patients was correlated with the percentage of ph chromosome positive cells and bcr - abl expression , indicating that it can be regulated by bcr - abl tyrosine kinase .
in fact , carter et al . demonstrated that bcr - abl and its downstream effector mitogen - activated protein kinase ( mapk ) could target survivin expression at both rna and protein levels in cells derived from a patient with cml - bp ph chromosome positive .
survivin downregulation resulted in reduced cell viability in imatinib - sensitive cml cells , but not in imatinib - resistant cml cells or ph chromosome negative cells , showing that survivin is regulated by the bcr - abl / mapk cascade in ph positive cml .
the prognostic importance of survivin in cml was also evaluated in a study from our group , where a correlation between survivin highest levels and high / intermediate sokal score patients could be observed .
in addition , it was reported that survivin overexpression at diagnosis correlated with a low probability to achieve an optimal response to imatinib .
these data suggest that survivin may be closely involved in a more aggressive evolution of cml .
growing evidence suggests that survivin plays an important role in chemoresistance phenotype of human malignancies , including cml .
it has been demonstrated by our group that treatment of k562 cml cells with imatinib resulted in survivin downregulation and cell death .
consistent with this , imatinib - induced apoptosis was increased when survivin expression was disrupted in bcr - abl cells , as shown by enhanced cytochrome c release , caspase-9 activity , and bcr - abl cleavage 199 , which indicate that targeting survivin might be a useful tool to sensitize bcr - abl cells to imatinib .
survivin has also been shown to play a resistant factor to agents other than imatinib in cml cells . in a recent publication
, our group showed that survivin overexpression was involved in the resistance to idarubicin , an anthracycline commonly used to treat acute leukemia . on the other hand
, idarubicin could induce dna fragmentation and caspase - mediated apoptosis in k562 cells when survivin levels were down - regulated .
in addition , other groups have demonstrated that survivin inhibition is a common mechanism of apoptosis induced in cml cells by different classes of anticancer agents such as aurora kinase inhibitors , histone deacetylase inhibitors , microtubule targeting agents ( mtas ) , and cyclin - dependent kinase ( cdk1 ) inhibitors .
altogether , this amount of data shows that the modulation of survivin expression seems to be an interesting approach to overcome resistance and induce cell death in cml cells . in recent years
, considerable efforts have been made to validate survivin as a new target in cancer therapy .
ym-155 , a small - molecule inhibitor of survivin , was the first survivin - targeted therapy to be developed and tested in clinical trials . in cml ,
ym-155 anticancer efficacy has been recently assessed in a preclinical study , where cml - derived cell lines showed great sensitivity to the molecule .
this effect has also been demonstrated for sheperdin , which is a novel antagonist of the interaction between hsp90 and survivin , known to be important for stabilizing survivin cytoprotective functions . although sheperdin did not decrease the viability of phytohemagglutinin - stimulated peripheral blood mononuclear cells or induced organ toxicity in a xenograft acute myeloid leukemia ( aml ) model
, it could inhibit viability in k562 cells and in patient - derived aml peripheral blasts , demonstrating that it is a highly selective molecule .
antisurvivin therapies developed , to date , have not revealed major systemic toxicities in animal models and clinical trials and are extremely encouraging .
targeting survivin alone or in conjunction with chemotherapeutic agents has a great potential as a novel therapeutic regimen in cml .
signal transduction pathways within the cell act by transmitting the extracellular signals to transcription factors , which result in changes in gene expression . however , it is well known that most key signaling pathways are deregulated in cancer , leading to altered expression and function of transcription factors . the constitutive activation of the nuclear factor kappa b ( nfb ) and the inactivation of the forkhead box o ( foxo ) factors were shown to be important steps in carcinogenic transformation .
therefore , modulating the activity of foxo and nfb seems to represent a reasonable therapeutic strategy .
nuclear factor b ( nfb ) was discovered in 1986 as a factor in the nucleus of b cells that bind to the enhancer of the kappa light chain of immunoglobulin .
it has been shown to be expressed in the cytoplasm of all cell types and , once activated , it translocates to the nucleus , where it regulates the expression of over 200 genes .
nfb is an important transcription factor typically activated by proinflammatory cytokines and other specific stimuli , and is involved in the regulation of a variety of biological responses , such as inflammatory , apoptotic , and immune processes .
it achieves this by regulating the expression of proteins such as cytokines , chemokines , adhesion molecules , and the cellular death cascade .
the members of nfb protein family form dimers ( usually heterodimers of p50 and p65 subunits ) that interact in the cytoplasm with inhibitor of nfb ( ib ) proteins .
when ib is phosphorylated by ib kinases ( ikks ) , it is degraded by the ubiquitin - proteasome pathway , liberating nfb dimers from their inhibition and allowing them to migrate to the nucleus and to activate nfb target genes .
in addition to its function as a central mediator of human immune responses , nfb plays a major role in activating genes involved in cellular survival , transformation , and oncogenesis .
loss of the normal regulation of nfb has become apparent as a major contributor to the deregulated growth , resistance to apoptosis , and propensity to metastasize observed in many cancers .
the overexpression of p65- or c - rel - containing dimers can impair apoptosis , whereas the inhibition of nfb / rel activity can enhance death induced by tnf - alpha , ionizing radiations , or chemotherapeutic agents in many cell types .
aberrant activation of nfb / rel factors contributes to reduce the sensitivity to apoptosis in a vast range of hematologic malignancies .
although alterations in nfb or ib genes are documented in some neoplasms , in other cases , dysfunctions in components of the nfb / rel - activating signaling pathways or influences of other mutated proteins on nfb / rel can be recognized .
constitutively active nfb has been detected in malignant cells derived from patients with multiple myeloma , aml , all , cml , and , most recently , in myelodysplastic syndromes .
targeting nfb in these hematopoietic malignancies leads to apoptosis , corroborating the role of nfb in the survival and clonal expansion of malignant cells .
the expression of bcr - abl leads to the activation of nfb - dependent transcription by causing nuclear translocation of nfb and by increasing the transactivation function of the rela / p65 subunit of nfb .
importantly , this activation is dependent on the tyrosine kinase activity of bcr - abl that partially requires ras .
it has also been demonstrated that nfb is required for bcr - abl - mediated tumorigenicity in nude mice and for transformation of primary bone marrow cells .
this activation regulates the transcription of important genes , such as c - myc , which are necessary for the transformation of bcr - ablcells , as well as surface molecules , which are necessary for cellular adhesion and interaction , giving advantages for cellular growth [ 161 , 177 ] .
in particular , the constitutive activation of nfb exists selectively in leukemia stem cells but not in normal hsc .
alterations in nfb regulation and in the signaling pathways that control its activities are involved in cancer progression , as well as in the treatment resistance during chemo- and radiotherapy .
nfb blocking can stop the proliferation of tumor cells or cause the tumor cells to become more sensitive to antitumor agents . this way , drugs that are capable of suppressing nfb activation have important therapeutic potential in the carcinogenesis inhibition .
several studies have demonstrated that the expression of bcr - abl kinase activity in cml cell lines leads to a constitutive activation of nfb through ikk downstream of bcr - abl and the suppression of nfb activation by the expression of ib blocked bcr - abl - dependent xenograft tumor formation [ 161163 ] .
. demonstrated that a selective inhibitor of the ib kinase ( ikk ) was capable of reducing nfb binding activity and proliferation , followed by induction of apoptosis in cml cell lines sensitive and resistant to imatinib , as well as in bone marrow cells from sensitive and resistant cml patients . corroborating with these data , duncan et al
. demonstrated that a selective ikk inhibitor strongly suppressed growth and viability and induced cell death of cell lines expressing either wild - type or mutant versions of bcr - abl , including the t315i mutation .
used another ikk inhibitor to block nfb pathway capable of reducing cell survival and inducing apoptosis of imatinib - sensitive and imatinib - resistant cell lines .
this work also demonstrated that cells from patients with t315i mutation appeared sensitive to nfb inhibition in terms of proliferation .
furthermore , in vivo experiments resulted in a significant regression of the tumors after the administration of the ikk-inhibitor in nude mice injected with bcr - abl wild - type and t315i mutant cells .
taken together , these results indicate that nfb / ikk is essential for bcr - abl induced cell growth and survival and that the kinase ikk represents an attractive therapeutic target in cml . among these compounds acting as nfb inhibitors , proteasome inhibitors have been widely used .
recently , it has been shown that bcr - abl induces the activity of the proteasome , supporting the idea of using the proteasome as a suitable target for bcr - abl - expressing cells .
the proteasome inhibition results in the accumulation of ib in the cytoplasm , leading to inhibition of nfb translocation to the nucleus . the most used proteasome inhibitor is bortezomib / velcade / ps341 , inhibitor of the chymotrypsin - like activity of the 5 subunit of the proteasome . in several studies ,
proteasome inhibition induced proliferation arrest and apoptosis in imatinib - resistant cells , providing a rationale for the use of this drug in the subset of patients resistant to imatinib [ 164 , 165 ] .
the combinatory regimens in cml murine models significantly reduced disseminated disease , decreased tumor growth , and induced apoptosis in tumor sections . in this work ,
. demonstrated that bortezomib reduces proliferation and survival of bcr - abl- expressing cells , regardless of their sensitivity to imatinib , and including the highly resistant mutant t315i . in both studies ,
bortezomib inhibited proteasomal degradation of ib , leading to its accumulation . taken together , these results suggest that an approach combining imatinib and proteasome inhibitors can be a therapeutic strategy in reducing relapse and overcoming imatinib resistance by inactivating the nfb pathway .
foxo transcription factors belong to the forkhead family of proteins , which are characterized by a conserved dna - binding domain termed forkhead box ( fox ) .
the foxo class contains four members : foxo1 , foxo3a , foxo4 , and foxo6 , whose expression can be found in a variety of different tissues .
foxo proteins are implicated in crucial cellular functions including cell cycle regulation , stress response , glucose metabolism , and apoptosis .
accumulating evidence suggests that foxo act as tumor suppressors , inhibiting tumor growth by the activation of genes such as bim , fasl , p27kip , cyclin d , gadd45a , glucose-9-phosphatase , and manganese dismutase . except for foxo6 , which is constitutively nuclear , phosphorylation by kinases , mainly akt , erk , ( ib kinase ) ikk , and serum and glucocorticoid - regulated kinase ( sgk ) , regulates foxo nuclear / cytoplasmic shuttling , leading to its nuclear exclusion , retention in the cytoplasm , and subsequent proteasome degradation and inactivation .
foxo transcription factors can also be regulated by other posttranslational modifications such as acetylation , methylation , ubiquitination , and glycosylation . because bcr / abl activity requires an activated pi3k / akt pathway and the inactivation of foxo transcription factors
was shown to be essential for tumorigenesis and resistance to treatment , the activation of foxo by chemotherapeutic drugs seems to be a great strategy to overcome resistance .
komatsu et al . showed that bcr - abl - positive cells have foxo3a in a constitutively phosphorylated status and p27/kip1 downregulated . in agreement , exposure of cml cells to imatinib inhibited foxo3a phosphorylation and induced p27/kip1 expression and g0/g1 arrest , blocking cell cycle progression .
. also showed that bcr - abl inhibition induced by imatinib in cml cells resulted in foxo3a activation .
as a consequence , the induction of the foxo3a - direct transcriptional target bim was observed concomitantly with increased apoptosis .
more recently , it was demonstrated that bcr - abl - mediated foxo3a inactivation was proteasome dependent .
bortezomib treatment was able to restore foxo3a expression , sensitize bcr - abl t315i expressing cells to apoptosis , and inhibit cml - like disease in leukemic mice .
regulation of foxo3a expression affects the expression not only of bim and p27/kip1 , but also of cyclin d .
imatinib - mediated inhibition of bcr - abl represses cyclin d4 expression , upon foxo3a activation and binding to cyclin d4 promoter .
however , this effect can be prevented after foxo3a silencing , indicating that foxo3a is a key signaling molecule for bcr - abl pathway and a relevant factor for apoptosis and cell cycle arrest in cml cells .
imatinib can also exert its antileukemic effects through the concomitant activation of foxo3a and the down - regulation of the inhibitor of dna binding 1 ( id1 ) in k562 cells .
this study demonstrated that id1 promoter is transcriptionally inhibited by foxo3a , leading to differentiation of bcr - abl transformed cells , suggesting that id1 is essential for maintaining the leukemia phenotype .
moreover , experimental data suggest that foxo3a activation can overcome imatinib resistance by increasing tumor necrosis factor - related apoptosis - inducing ligand ( trail ) expression and by inducing apoptosis , further emphasizing the importance of the foxo pathway in determining drug sensitivity .
although a great amount of evidence demonstrates that foxo3a functions as a downstream factor for tki - induced apoptosis , recent data suggest that foxo3a has a crucial role in maintenance of cml stem cells . in a recent study , it was demonstrated that foxo3a deficiency is associated with a decreased ability of leukemia - initiating cells ( lics ) to provoke cml in foxo3a mice .
moreover , in cml stem cells , foxo3a is predominantly nuclear and plays a resistant factor against tki therapy .
corroborating these data , the transcription factor bcl-6 was identified as a target for the foxo family , responsible for cml stem cells ' self - renewal , repression of p53 , leukemia initiation and resistance to tki treatment . as previously discussed , these findings reflect a stem cell paradox and may explain , in part , why cml stem cells persist after tki treatment . the mechanisms and implications of these unexpected results regarding
, various findings have found that the activation of foxo3a and its downstream genes are of clinical importance in diverse anticancer therapeutics , including in cml treatment .
different from p53 , foxo mutation has not yet been found in human cancer , favoring foxo targeted therapy .
clinical drugs which activate foxo transcription factors can be used in combination with therapeutic agents for sensitizing cml malignant cells to therapy .
growing evidence has demonstrated that the development of the mdr phenotype arises as a result of a complex network involving multiple cellular and molecular mechanisms .
it is a multifactorial process rather than a consequence of a single and isolated mechanism ( figure 1 ) . as the problem of drug resistance
can not be solved by circumventing only an individual protein , many efforts have been made in order to target diverse mechanisms and enhance cell sensitivity to antineoplastic therapy ( table 1 ) .
wang et al . had suggested that clinical responses to imatinib treatment could be affected by transporters slc22a1 , abcb1 , and abcg2 ; however , a recent work showed no significant differences between abcb1 , abcg2 , and slc22a1 genotypes and imatinib plasma or intracellular concentrations .
these data indicate that other transporters may be crucial for determining imatinib intracellular and plasma concentrations in cml patients .
by contrast , in experiments using in vitro models of acquired resistance , k562 cells displayed upregulated levels of abcb1 and abcg2 genes , after exposure to increasing concentrations of imatinib [ 167 , 168 ] , which would imply the involvement of these transporters in resistance to tkis . however , different from the abcg2 inhibitor , the abcb1 inhibitor was able to restore imatinib sensitivity , indicating that only abcb1 is essential for the development of acquired resistance in cml .
regarding the expression of slc22a1 gene , contradictory data show that k562 resistant - cells had an increased or similar expression compared to their parental ones .
another work has demonstrated that imatinib and nilotinib are capable of inhibiting abcb1 and abcg2 and may overcome resistance , despite high levels of these transporters .
current studies have proposed the role of iaps in mdr phenotype promotion in association with abcb1 expression .
recently , we evaluated the resistance induced by the overexpression of both abcb1 and survivin proteins . in this work
, we showed that k562 cells ( abcb1-negative ) progressively became resistant to vincristine treatment by simultaneous overexpression of abcb1 and survivin .
we also showed that abcb1 promoted resistance to cell death independently of its membrane expression . besides that
, we could observe that abcb1 and survivin colocalize in the cytoplasmatic compartment , suggesting a common regulatory pathway of apoptosis resistance control . in another work
, we observed that both abcb1 and survivin protein expressions are associated in cml patients .
we could establish a positive correlation between abcb1 and survivin expression , but not with abcb1 activity in samples from late - phase cml - cp patients .
these data suggest that abcb1 and survivin may act in promoting resistance in cml patients and , thus , reinforce the hypothesis that abcb1 is able to induce resistance independently of its activity function .
as discussed above , cml patients usually develop imatinib resistance , and , therefore , new treatment approaches are necessary to overcome cml resistance .
netto et al . showed that a new compound named lqb-118 was effective against leukemia cell lines with low toxicity to peripheral blood cells .
recently , we evaluated the effect of lqb-118 on cml cell lines and observed that this compound was able to induce apoptosis in both sensitive and resistant cml cells .
moreover , cells treated with lqb-118 also presented decreased levels of survivin , xiap , and abcb1 expression .
we also analyzed the lqb-118 effect in cml patient samples and observed that this compound was effective in inducing apoptosis in patients displaying the mdr phenotype .
. showed that the simultaneous inhibition of xiap and abcb1 in cells overexpressing abcb1 could decrease imatinib resistance .
recent studies reported that abcb1 expression can be regulated by the nfb transcription factor in hepatocytes and in drug - resistant cells .
moreover , the inhibition of nfb activity sensitizes resistant colon cancer cells through a decreased abcb1 expression , providing a link between nfb and resistance to chemotherapy through the regulation of human abcb1 gene expression . in cml ,
assef et al . demonstrated that the resistance to imatinib exhibited in multidrug - resistant human leukemic k562 cells mediated by abcb1 was reversed by the blockade of the nfb pathway using a specific nfb inhibitor .
moreover , experimental evidence demonstrated the enhanced binding of nfb to the promoter region of abcb1 after k562 treatment with doxorubicin , further confirming the regulation of abcb1 by nfb in the promotion of chemoresistance . in accordance to that ,
some reports have postulated that chronic induction of foxo3a expression and nuclear localization may activate mechanisms of resistance in cml cells . by using doxorubicin - sensitive and resistant k562 cml cells , hui et al .
[ 200 , 201 ] have demonstrated that resistance to doxorubicin is associated with increased activity of pi3k / akt , through a mechanism of feedback and with the abcb1 gene induction .
in contrast , it was recently demonstrated that foxo3a is able to inhibit survivin expression while inducing cell death in melanoma and neuroblastoma - derived cell lines .
moreover , foxo3a and foxo1 were able to physically interact and inhibit survivin promoter , confirming the interaction between foxo transcription factors and the antiapoptotic protein survivin .
however , the interaction between survivin and foxo proteins , and its role in imatinib sensitivity , has not been investigated yet in cml - derived cells .
survivin can also be targeted by nfb , although it remains unclear how this interaction occurs .
it was reported that inhibitors of the nfb pathway , such as the natural compounds triptolide and berbamine , have been shown to induce apoptosis in cml imatinib - resistant cells by down - regulating survivin levels .
xiap is another identified nfb target , which is also implicated in modulating nfb activation , through a feedback loop mechanism , in response to dna damage and bacterial infection .
studies suggest that xiap recruits tak1 in order to achieve nfb activation and can mediate nfb activation by promoting degradation of commd1 , a negative regulator of nfb . as survivin ,
although the introduction of imatinib and other tkis in cml therapy has brought improvements in survival , cml prognosis still remains unfavorable for a group of patients .
in addition to mutations found in the bcr - abl gene , which alter the bcr - abl kinase domain , there are currently identified secondary mechanisms of tkis resistance .
multiple factors , such as inhibition of apoptotic signaling pathways , reduction in drug accumulation , and alterations in transcription factors , are known to contribute to the development of mdr and treatment failure in cml .
these mechanisms usually act in concert in a multifactorial resistance context and play their role independent of or downstream bcr - abl tyrosine kinase . because the inhibition of only one mechanism is not effective enough to overcome clinical tkis resistance , suppressing simultaneously
several proteins must be required to increase the efficacy of the treatment in cml patients .
several questions remain to be answered to understand the interplay between these modes of resistance . for instance , how these proteins interact with each other to promote resistance and which one must be completely suppressed to antagonize malignancy ?
regardless , what we know is that chemoresistance in cml is a multifactorial phenomenon and targeting these molecules seems to represent an interesting and feasible approach to overcome the development of tkis - resistance in cml . | ### Summary:
: chronic myeloid leukemia ( cml ) is a clonal hematopoietic disorder characterized by the presence of the philadelphia chromosome which resulted from the reciprocal translocation between chromosomes 9 and 22 .
the pathogenesis of cml involves the constitutive activation of the bcr - abl tyrosine kinase , which governs malignant disease by activating multiple signal transduction pathways .
the bcr - abl kinase inhibitor , imatinib , is the front - line treatment for cml , but the emergence of imatinib resistance and other tyrosine kinase inhibitors ( tkis ) has called attention for additional resistance mechanisms and has led to the search for alternative drug treatments . in this paper , we discuss our current understanding of mechanisms , related or unrelated to bcr - abl , which have been shown to account for chemoresistance and treatment failure .
we focus on the potential role of the influx and efflux transporters , the inhibitor of apoptosis proteins , and transcription factor - mediated signals as feasible molecular targets to overcome the development of tkis resistance in cml . |
<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 5-week postpartum woman presented to the emergency room with complaints of nausea and vomiting for 48 h. she also reported a 2-day history of general malaise and worsening dyspnoea .
she reported eating ; however , she limited herself to several small high - protein carbohydrate - free meals in an attempt to quickly return to her prepartum weight . since her delivery
initial vital signs were : temperature 37 c , blood pressure 140/63 mmhg , heart rate 84 , respiratory rate 20 and a weight of 59.8 kg .
the abdomen was benign with a well - healed surgical c - section scar ; there was no costovertebral angle tenderness .
her past medical history was significant for a cesarean section , complicated by bladder damage , now resolved .
initial laboratory data include sodium of 144 meq / l , potassium 4.8 meq / l , chloride 104 meq / l and bicarbonate < 5
her bun was 3 mg / dl , creatinine was 1.1 mg / dl and glucose was 133 mg / dl .
mmol / l , phosphate 1.0 mg / dl and magnesium 1.6 mg / dl .
arterial blood gas drawn on room air showed a ph of 6.9 , pco2 of 19 mmhg , pao2 of 137 mmhg and sao2 of 100% .
white blood cell count was 17 600/mm with 88.2% segmented neutrophils , hg 13.7 g / dl , haematocrit 43.1% and platelets of 340 000/mm .
the patient was volume - depleted with a metabolic acidosis and a serum anion gap of 35 .
fluid resuscitation with three ampules of sodium bicarbonate per litre of d5w at 100 cc / h was initiated for 24 h. improvement in laboratory values occurred within 12 h with serum bicarbonate improving to 12 meq / l .
the serum bicarbonate improved to 20 meq / l with normalization of the anion gap at 24 h. symptomatic improvement occurred likewise .
the patient was started on an 1800 kcal diet during her hospitalization , supplemented with a regular diet of home food provided by the husband .
breast feeding was stopped on advice from a lactation consultant and the acidosis did not reoccur .
the patient 's baby was reported to be in the 90th percentile for weight and height .
the differential for increased anion gap metabolic acidosis is broad and includes poorly controlled diabetes , ketoacidosis due to alcohol or starvation , lactic acidosis , some medications or ingestions of methanol or ethylene glycol .
uncontrolled diabetes mellitus is the most commonly seen cause of increased anion gap metabolic acidosis . here
, insulin deficiency increases lipolysis , free fatty acid delivery to the liver , while glucagon promotes conversion of free fatty acids into ketoacids .
acidosis seen with alcohol ingestion can potentiate the severity of other disorders that are associated with the overproduction of lactate .
the combination of alcohol ingestion and poor dietary intake also leads to an acidosis secondary to ketosis .
alcoholics tend to have a decreased oral intake that reduces insulin secretion and increases glucagon production .
in addition , alcohol - induced inhibition of gluconeogenesis and stimulation of lipolysis all contribute to acidosis through increased ketoacid production .
many cases in hospitalized patients are due to tissue hypoperfusion that occurs with shock , cardiac failure or sepsis .
it reduces pyruvate dehydrogenase activity and mitochondrial transport of reducing agents , and thus enhances anaerobic metabolism .
inhibition of pyruvate dehydrogenase results in increased metabolism of pyruvate to lactate and increases the net lactic acid production .
it is typically described with all nucleoside reverse transcriptase inhibitors , but patients taking stavudine or didanosine seem to be at a greater risk . methanol and ethylene glycol consumptions are well - known causes of anion gap metabolic acidosis .
they are found in automotive antifreeze , windshield wiper fluid , solvents and household cleaners .
the syndrome of bovine ketosis is well described in the veterinary literature of lactating cattle . in this disorder ,
the metabolic and glucose demands of milk production and secretion exceed the amount of ingested carbohydrate and glycogen stores in these chronically lactating animals .
bovine ketosis is rare in humans because it is uncommon for the mother to be unable to meet her own metabolic demands through diet .
the energy cost of breast feeding from birth to 6 months is an additional 500 kcal / day ; then for 7 months to 1 year , the additional energy required is 400 kcal .
these nutritional requirements needed to support lactation exceed the energy requirements during the non - pregnant state and are even beyond those needed during pregnancy .
it is therefore important to emphasize to patients that active weight loss should not be undertaken during breast feeding .
there have been two previous case reports : heffner and johnson reported a 35-year - old lactating woman with ketonuria , nondiabetic ketoacidosis and a ph of 7.24 .
altus and hickman described the case of a 30-year - old woman postpartum who presented with nausea , vomiting and dehydration .
her arterial ph was 7.07 , serum bicarbonate < 5 meq / l with positive urinary and serum ketones .
similar to the prior reports , our patient was under the stress of lactation but the degree of her acidosis , a serum ph of 6.9 , has not been previously reported .
we feel that in her case the relative starvation precipitated the ketoacidosis and the increased metabolic demands of lactation produced a life - threatening acidaemia . | ### Summary:
: a 36 year - old 5 weeks postpartum lactating woman presented to the emergency room with severe nausea and vomiting for 48 hours . the patient was found to be in non - diabetic ketoacidosis with a serum ph 6.9 and a hco3 of <
5meq / l .
this condition rapidly improved with the administration of intravenous dextrose and bicarbonate and with the cessation of breast feeding .
the course and pathophysiology of the rarely described phenomenon of bovine ketosis in a human is discussed here . |
<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:
: ramelteon ( tak-375 ; rozerem ) is a tricyclic synthetic analog of melatonin ( fig .
it was approved by the united states food and drug administration ( fda ) in 2005 for the treatment of insomnia . in europe ,
the marketing authorization application was withdrawn in 2008 . unlike other melatonergic agonists , such as agomelatine
, ramelteon is a specific agonist that acts via mt1 and mt2 receptors without any known clinically relevant affinity for other receptors.18 ramelteon has a very low affinity for the serotonin receptor 5-ht1a ( ki = 5.6 m),8 a property which is apparently clinically irrelevant .
classic hypnotics acting via gabaa receptors , such as benzodiazepines , cause various und esired side effects , including next - day hangover , transitory cognitive and memory impairments , rebound insomnia after withdrawal , and have the potential for tolerance development , dependence and drug abuse.9 these problems are less severe with the later developed z - drugs , which are , however , not entirely devoid of side effects10 and can sometimes induce behavioral changes.11 trazodone , a triazolopyridine antidepressant and sedating agent , frequently prescribed for the treatment of insomnia , has been shown to cause cardiac rhythm disturbances and orthostatic hypotension.12 since various forms of insomnia are related to circadian rhythm dysfunction , none of these drugs can be expected to have causal treatment efficacy in cases of reduced circadian functionality , whereas the pineal hormone melatonin can directly readjust the circadian oscillator system owing to its chronobiotic properties .
moreover , melatonin is directly involved in the circadian phasing of sleep , and , in diurnally active mammals , including humans , especially in the initiation of sleep .
however , melatonin has the disadvantage of having an extremely short half - life in the circulation , which is frequently below 30 min.13,14 taken together , these considerations provided a significant justification for the development of longer acting melatonergic agonists , such as ramelteon .
ramelteon , which is usually administered orally in a dose of 8 mg , is rapidly absorbed and reaches peak serum concentrations of 5700 pg / ml within 0.5 to 1.5 h.7 by contrast , a comparable dose of melatonin decreases over the same time period from peak values to less than 1000 pg / ml . in serum , 82% of the ramelteon
is bound to plasma proteins and , like melatonin,15 70% of circulating ramelteon is bound to plasma albumin . in humans , ramelteon has been tested in doses ranging from 4 to 64 mg.7 the absorption of orally administered ramelteon is at least 84% , but its absolute bioavailability is only about 1.8% because of extensive first - pass metabolism , and also , presumably , because of uptake by tissues .
intravenously administered ramelteon has been shown to reach a distribution volume of 73.6 l.7 ramelteon s unique molecular structure ( fig .
1 ) , ie , a propionyl group instead of acetyl group , two hydrocarbon atoms in a furan ring instead of a methoxy group , and its lack of nitrogen in 5-atom ring , are factors that particularly facilitate its tissue distribution . compared with melatonin , which itself enters tissues with ease , ramelteon has even greater lipophilicity , and consequently it penetrates and is absorbed more easily into tissue .
the half - life of circulating ramelteon is in the range of 12 h , depending on the dose,7 which is considerably longer than that of melatonin .
moreover , one of ramelteon s metabolites , the bioactive compound m - ii ( fig .
1 ) , is much more slowly eliminated , so that the functional half - life of the drug including m - ii is extended to about 5 h. this might be regarded as a decisive advantage for sleep promotion , because the relatively poor efficiency of melatonin in supporting sleep maintenance is presumed to result from its rapid decay . as outlined above , ramelteon shows a high affinity for mt1 and mt2 receptors and displays very low affinity for other cns receptor binding sites ( eg , gaba receptors ) .
based on pharmacokinetic studies , four metabolites of ramelteon have been identified : m - i , m - ii , m - iii and m - iv ( fig . 1).7 metabolite m - i is formed by cleavage of the furan ring , which leads to replacement of the oxygen atom with a hydroxyl group .
ring cleavage takes place through formation of a carboxyl group , which is reminiscent of a dioxygenation step .
whether such a reaction can be attributed to a cytochrome p450 ( cyp ) enzymatic activity remains to be clarified .
the m - ii metabolite of ramelteon ( 2-hydroxy - n- [ 2-(2,6,7,8-tetrahydro-1h - indeno[5,4-b]furan-8-yl ) ethyl]propanamide ) ( fig .
1 ) , exerts selective actions on mt1 and mt2 receptors , as does the parent compound , but it is only about 10% as potent as ramelteon itself . of these , only m - ii can be explained by a single enzymatic hydroxylation step .
this compound , which represents the major metabolite , carries a hydroxyl group at c2 of the propionyl residue .
the affinity of m - ii for melatonin receptors is not surprising in view of its similarity to ramelteon .
m - ii circulates at much higher concentrations , however , resulting in a 20100 fold greater mean systemic exposure , so it is likely to contribute to ramelteon s biological effects.7 metabolite m - iv differs from m - iii by the presence of an aliphatic hydroxyl group as in m - ii , and might be formed from either m - ii or m - iii.7 the metabolites m - iii and m - iv carry a carbonyl group in a position that would be impossible for melatonin , because the relevant carbon atom in ramelteon corresponds to the indolic nitrogen atom in melatonin .
again , the introduction of the carbonyl group can not be explained by a single hydroxylation step , but would require an additional oxidation .
it might be assumed that the monohydroxylated indene formed by cyp is a reactive intermediate , which readily undergoes further oxidation .
the possible significance of a reactive intermediate has , however , never been addressed in either pharmacological or toxicological terms .
the metabolism and oxidation chemistry of ramelteon are thus entirely different from those of melatonin .
although ramelteon and melatonin are both substrates of hepatic p450 monooxygenases mainly cyp1a2 and , to a minor extent , cyp2c subforms and cyp3a4the sites of oxidation of ramelteon are different from those of the melatonin molecule .
ramelteon is less rapidly eliminated than melatonin , but it is still eliminated at a rate sufficient to avoid accumulation . less than 0.1% of the radiolabeled drug is excreted non - metabolized ; 84% of radioactivity appears in the urine and 4% in the feces.7 total elimination is completed within 96 h. it should be noted that the half - life of m - ii is 25 hours longer than that of the parent compound.7 in view of the fact that ramelteon is mainly metabolized by cyp1a2 and cyp2c19 , drugs that inhibit these enzymes can considerably increase the levels of the agonist . in human liver microsomes ,
cyp1a2 , cyp2c19 and cyp3a4 contribute 49 , 42 , and 8.6% , respectively , to the metabolism of the agonist.16 consequently , ramelteon should not be used in combination with fluvoxamine , ciprofloxacin , mexiletine , norfloxacin , tacrine or zileuton.8 the extent of drugdrug interactions can be remarkable : for instance , coadministration of fluvoxamine has been shown to produce more than 100-fold increases of ramelteon plasma concentrations.16 substantial increases in ramelteon levels have also been observed when it was administered with the cyp2c9 inhibitor fluconazole and the cyp3a4 inhibitor ketoconazole , whereas compounds affecting various other p450 enzymes have not produced meaningful changes .
the cyp inducer rifampin has been shown to considerably decrease levels of both ramelteon and its metabolite m - ii . to avoid losses in efficacy , this and other strong upregulators of relevant cyp enzymes should be avoided.8 stated
more simply , ramelteon , like melatonin , exerts its direct sleep - inducing effects via mt1 receptors located in the hypothalamic suprachiasmatic nucleus ( scn ) , while its phase shifting effects may be mediated via mt2 receptors.17 in the human scn , the role of mt2 remains to be clarified .
since ramelteon s direct soporific effect , as measured by reduction of sleep onset latency ( sol ) ( but not the phase shifting capacity ) is indistinguishable at 4 mg and 8 mg doses , ramelteon seems to promote sleep by regulating the sleep / wake cycle rather than by having a more generalized cns - depressant effect .
this is supported by the observations that ramelteon does not worsen sleep apnea in insomniacs.17 due to the potency of its effects on melatonin receptors in the scn , ramelteon apparently accelerates sleep onset by influencing the hypothalamic sleep - switch
downstream from the scn , essentially in the same way as melatonin , but , owing to its higher receptor affinity , does so more efficiently.18 the sleep - switch model , originally proposed by saper and colleagues , describes flip - flop mutual inhibitions among sleep - associated activities in the ventrolateral preoptic nucleus ( vlpo ) and wakefulness associated activities in the locus coeruleus ( lc ) , dorsal raphe nucleus ( drn ) and tuberomammillary nucleus ( n).1922 it has been hypothesized that the prolonged use of ramelteon , like melatonin,23 could result in desensitization of melatonin receptors in the scn . from studies of the scn or immortalized scn2.2 neurons desensitization and internalization of mt2 receptors is known to occur following exogenous melatonin administration.23,24 whether downregulation by ramelteon is stronger or longer - lasting or even occurs at all , remains to be demonstrated . in any event , the studies of its actions to date indicate that ramelteon represents a good pharmacological option for the treatment of sleep initiation in insomnia and thus has a promising future for use with chronic insomnia patients.6,2532
clinical evidence indicating that ramelteon does not alter sleep architecture and tends to be well tolerated is consistent with what is known about its pharmacokinetic activity .
melatonin receptors ( both mt1 and mt2 ) are present in high densities in rodent scn.33,34 in human scn , mt1 is particularly expressed in vasopressin neurons,35,36 a finding which is centrally relevant in as much as vasopressin release represents a major circadian output function of the scn.3739 mt2 was not detected in an earlier investigation of the human scn.40 this receptor subtype is expressed in the scn of numerous mammals and , where present , is particularly important for circadian phase shifting.4144 the scn is not the only site where melatonin receptors are found , and because sleep is not exclusively under circadian timing control , but is also influenced by homeostatic factors such as fever , hypothermia and infections , one question that remains to be addressed is whether ramelteon acts also as a chronobiotic , ie , a drug that directly influences circadian mechanisms.45 in this context it has already been shown that ramelteon has the ability to promote phase shifting in rodents,46 a capability that can be attributed to its action on the mt2 receptor .
activation of scn mt1 receptors attenuates the circadian wake - promoting signal , thereby prolonging the homeostatic mechanisms that underpin the sleep process .
this suggestion assumes that the principal effect of mt1 receptor activation is to suppress neuronal firing in the scn , and that phase effects make only a minor contribution to the process.41,47 stimulation of mt1 receptors inhibits neuronal firing in the scn of both diurnal and nocturnal animals but suppression of wakefulness via mt1 can only take place in diurnally active species such as primates.1922 as mentioned above , the sleep - switch model describes the mutual inhibitions among sleepassociated activities in vlpo and wakefulness - associated activities in lc , drn and n , as a system capable of changing in a flip - flop manner.1922 the scn can influence both of these subsystems through projections via the ventral subparaventricular zone to the hypothalamic dorsomedial nucleus , from which numerous circadian functions are regulated .
projections from the dorsomedial nucleus to the vlpo induce sleep , whereas projections to the lateral hypothalamus are associated with wakefulness
. both melatonin and ramelteon should be capable of influencing the switch via mt1 and mt2 receptors , thereby accelerating sleep onset . whether such melatonergic actions would also support sleep maintenance is not known .
this would depend on receptor availability throughout the sleep period ; that is , the efficiency of sleep maintenance might depend on duration and extent of receptor desensitization and internalization . in this respect ,
ramelteon s affinity for mt1 and mt2 receptors is greater than that of melatonin ( table 1 ) .
physiological sleep promotion by melatonin also includes effects on core body and skin temperatures . in order to distinguish drug effects from the circadian rhythm of body temperature
, one recent study has examined the effects of ramelteon ( 8 mg ) administration during the day .
similar to melatonin , ramelteon has been found to reduce core body temperature and to increase the distal - proximal skin temperature gradient.48 following recommended dose administrations of 8 mg , plasma levels of ramelteon are greater and longer lasting than those of melatonin .
consequently , ramelteon seems more likely to desensitize mt1 and mt2 receptors than would melatonin itself.8 more information is required concerning receptor downregulation by ramelteon .
the role of the scn in the control of sleep was first reported in diurnally active squirrel monkeys.49 in monkeys with scn lesions , consolidated sleep and wake periods were abolished and the animals slept more . based on such findings , it was proposed that the circadian signal arising from the scn promotes wakefulness during the day as well as consolidating sleep during the night.49 a study conducted in 22 young adult female monkeys ( macaca fascicularis ) included various measures based on cortical electroencephalography , electromyography and electrooculography.48 individual monkeys received , at 1000 h , different doses of ramelteon ( 0.003 , 0.03 and 0.3 mg / kg ) and , correspondingly , other animals were treated , at the same circadian phase , with different doses of melatonin ( 0.3 mg , 1 mg and 3 mg / kg ) . for comparison ,
zolpidem was administered to additional experimental groups ( 1 , 3 , 10 and 30 mg / kg ) .
the study demonstrated that ramelteon , in doses of 0.03 and 0.3 mg / kg , was effective in reducing the time to sleep onset as compared with controls.50 ramelteon , in these two doses , also significantly increased the total duration of sleep .
melatonin also tended to increase the total duration of sleep , but without attaining statistical significance .
zolpidem , in none of the doses tested ( 1 , 3 , 10 , 30 mg / kg ) , had any effect on the latency to light sleep or slow wave sleep ( sws ) , nor on total sleep time ( tst ) .
the investigators concluded that ramelteon reduced the latency to sleep onset and increased sleep duration in freely moving monkeys without producing any of the side effects often seen with benzodiazepines.50 in another study in monkeys , ramelteon did not promote physical dependence,51 a finding of particular importance for judging the clinical usefulness of the drug .
the sleep - promoting effects of ramelteon have been studied in several trials having different designs , using models of induced transient insomnia as well as various schedules for treating younger , middle - aged and elderly patients with chronic insomnia ( table 2 )
. a broad spectrum of doses ranging from 4 to 64 mg has been tested , but , in the majority of trials , the finally recommended dose of 8 mg has been applied .
sleep parameters have been objectively determined by polysomnography ( psg ) and/or , especially in studies of long duration with high numbers of outpatients , by subjective self - rating measures .
regardless of type of insomnia , schedule of treatment , age of patients , and evaluation of objective or subjective measures , the most consistently observed effect was a reduction of sleep onset latency , either as latency to persistent sleep ( lps ) or as subjective sleep latency ( ssl ) . despite some variation in significance levels resulting from the number of participants and study design , it can clearly be stated that ramelteon facilitates sleep onset .
the conclusion is also supported by a pooled analysis of four large trials.59 this effect is observed after a single dose as well as daily treatment for several weeks or months ( table 2 ) . sometimes , the level of significance decreases upon longer duration of treatment , but this is mainly due to progressing sleep improvements in the respective placebo groups .
findings relating to dose dependence do not allow a general conclusion . in some studies , slight increases in efficiency have been observed with higher doses , but , in other cases , the opposite has been found .
25 and 26 for lps , or refs . 6 and 27 for ssl ) .
nevertheless , one can state that doses above 8 mg ramelteon usually do not lead to further improvements of substantial value .
effects on sleep duration , determined either by psg as total sleep time ( tst ) or by self - rating as subjective total sleep time ( stst ) , have been much more variable than those on sleep latency ( table 2 ) .
although several studies reported significant improvements , this was not generally observed , even in larger studies and after prolonged treatment . nevertheless , it may be concluded that ramelteon leads to improvements in sleep duration , but their extent remains limited .
other sleep parameters , such as wake after sleep onset ( waso ) , subjective waso ( swaso ) and sleep efficiency ( se ) , are only slightly influenced by ramelteon ( table 2 ) .
the subjective measure of sleep quality , which has also been determined in several of the studies , was not included in the table since a level of significance was never consistently reached . in some studies
, intra - group heterogeneities may have gradually obscured ramelteon s soporific effects , since the causes of sleep disturbance can be highly divergent and may be associated with chronobiological and mood disorders , which may be a source of differences in symptom tractability .
the relevance of distinguishing between subgroups is indicated by a study , in which patients differing in their self - rating depression scale ( sds ) score were separately analyzed.55 patients with sds scores below 48 showed stronger and more sustained improvements in ssl than those with higher scores .
therefore , the possibility should be excluded that dysthymic patients only differ in their self - rating behavior .
another means of eliminating relevant intra - group heterogeneities is to exclude non - compliant patients from the evaluation.55 major differences to classic gabaergic hypnotics exist with regard to next - morning effects and withdrawal .
the absence of residual effects by ramelteon concerning morning alertness , various cognitive and psychomotor as well as mood parameters has been repeatedly documented.5,2527,32,52,56,60 patients reported feeling refreshed upon arising in the morning.6 minor deficits in morning alertness and ability to concentrate were only observed at the very high dose of 64 mg / day,5 which has not been applied in later studies . at a dose of 8 mg , ramelteon also did not impair memory and motor functions in older adults during the night , such as mobility and middle - of - the - night balance , findings that strongly contrast with those observed with zolpidem.60 importantly , ramelteon also does not induce changes in sleep architecture.27,52 moreover , no withdrawal symptoms have been observed , especially that of rebound insomnia,6,27,29,32,54,56,57 which is not uncommon with other hypnotics , in particular , benzodiazepines . instead ,
after a treatment for several weeks or longer , discontinuation typically leads to slow increases in sleep latency , but not to an immediate return to baseline .
the usefulness of ramelteon has been also studied in several disorders associated with sleep disturbances .
for instance , sleep difficulties have been reported as one of the most troubling manifestations of menopause.61,62 in older adults , insomnia is frequently associated with sleep apnea ( estimated co - morbidity 29%61%).58 data on peri- or postmenopausal women57 and older patients with obstructive sleep apnea58 are included in table 2 . in a double - blind , placebo- controlled study on bipolar i disorder with manic symptoms , ramelteon was applied as adjunctive therapy , but no effects on sleep parameters were demonstrable.63 this negative finding may have resulted from the small number of patients ( 10 with ramelteon , 11 with placebo ) . however , a few significant changes were observed in global ratings of depressive symptoms , such as quality of life ( according to pittsburgh insomnia rating scales ) and depression ( according to clinical global impressions scale , modified for bipolar illness ) .
this is in contrast to a study in which adjunctive long - acting melatonin had no significant antidepressant action in depressed patients.64 the findings of the ramelteon study suggest that , similar to agomelatine , ramelteon may be an effective melatonergic antidepressant drug , but unlike agomelatine , its actions are restricted to melatonergic mt1 and mt2 receptors , and have no effect on serotonergic receptors . alternately , the activation of the melatonin receptors may possibly potentiate the effects of antidepressant drugs . on the other hand ,
interpretations of antidepressant effects in bipolar disorders have to consider the largely chronobiological nature of these diseases , which are characterized by severely disrupted circadian rhythms , in the majority of patients.65 it should also be pointed out that sleep symptoms are a component of the global ratings for depression so that improvement in these ratings could simply represent an improvement in sleep .
clarification of this issue will depend on further studies aimed at disentangling the symptoms of disrupted sleep and depression , and , more fundamentally , how these symptoms may relate to underlying circadian dysfunctionalities .
the effectiveness and tolerability of ramelteon was also examined in an open label study of 27 adult patients who met dsm - iv diagnostic criteria for generalized anxiety disorder ( gad ) and who had disturbed sleep.66 after 12 weeks , a significant symptom reduction was observed on all scales of clinical global impression indices , with subjects falling asleep faster and sleeping longer .
ramelteon may be an effective treatment for insomnia symptoms in patients with gad.66 however , the data obtained can not be easily compared with sleep parameters of other studies , not only because of the clinical scales used , but mainly because of the continued medication with escitalopram or other antidepressants / anxiolytics . since sleep
is also controlled by the circadian oscillator system and since phase shifts cause sleep disturbances , the effects of the melatonergic drug ramelteon was also of interest in this context .
in 110 healthy adults with a history of jet lag , ramelteon ( 1 , 4 or 8 mg ) was given before bedtime following an eastward travel across five time - zones from hawaii to the east coast of us.67 reductions of lps were only demonstrable at low significance levels and not under any condition , presumably because of the small number of participants in the respective subgroups .
more pronounced effects on lps were obtained in a subset of participants who were kept in dim light throughout the study . delayed sleep phase syndrome ( dsps ) is a circadian rhythm sleep disorder ( crsd ) in which sleep onset latency is delayed , in some cases by as much as 2 to 6 hours .
it is characterized by chronic inability to fall asleep at the desired clock time.68,69 there is compelling evidence to implicate changes in the endogenous melatonin pattern as an important factor in the pathophysiology of crsd.69 in fact , the administration of 5 mg melatonin was reported to advance sleep onset time by an average of 82 min ( range 19124 min ) and waking time by 117 min in patients with dsps.70 the therapeutic potential of ramelteon for treating crsd has been indicated by studies on the phase - shifting capacity of varying doses of the compound in healthy subjects.71 ramelteon , at doses of 1 , 2 , 4 , and 8 mg , was administered to 75 adults of the age group 1845 years for 6 days .
administration of 1 , 2 , or 4 mg of ramelteon for a period of 4 days was found to cause significant phase advance shifts , as assessed by determining the dim light melatonin offset effect , ie , the time point when salivary melatonin decreases to below 3 pg / ml ( normally after morning awakening ) .
shifts of 7.1 18.6 , 88 16.6 ( p = 0.002 ) , 80.5 14.8 ( p = 0.003 ) and 90.5 15.2 min ( p = 0.001 ) were determined for placebo , and 1 , 2 and 4 mg ramelteon , respectively .
surprisingly , a higher dose of ramelteon ( 8 mg / day ) did not cause significant changes as compared to placebo [ 27.9 16.4 min ( p = 0.392 ) ] , an unexpected divergence between the soporific effect and phase shifting .
in comparison to the safety of other newly introduced drugs , ramelteon appears to be well tolerated , at least during short - term treatment .
although the extent and duration of melatonin receptor desensitization following ramelteon therapy are unknown , these effects may be limited .
moreover , clinical studies of ramelteon carried out to date have shown little evidence of next - day hangover , withdrawal symptoms or rebound insomnia.5,6 toxicological data have sufficed for us fda approval .
interference with other drugs in particular , those changing cyp activities and precautions concerning the use of alcohol , high - fat meals , hepatic and renal impairment and pregnancy have been documented.8,25,72 the reported incidence of adverse effects of ramelteon , as inferred from subjects complaints and neurological parameters , has been similar to that of placebo . in a study by erman et al
the incidence of treatment - emergent adverse events ranged from 8.4 to 10.7% among the ramelteon groups and was 8.7% in the placebo group.25 the most commonly reported adverse events were headache , somnolence , dizziness and sore throat . in as much as all currently available benzodiazepines and non - benzodiazepine hypnotics
cause either addiction , withdrawal symptoms or trigger rebound insomnia , the relative absence of symptoms following the use of ramelteon is noteworthy and underscores its specific advantages for the treatment of insomnia .
ramelteon s efficacy and favorable side effect profile have been further confirmed in a recent open label study , in which subjects with primary insomnia received ramelteon nightly for 1 year.30 subjects aged 65 or more years received ramelteon 8 mg ( n = 248 ) while those aged 18 to 64 years received ramelteon 16 mg ( n = 965 ) .
ramelteon was associated with sustained improvements in subjective sleep latency , subjective tst , and in the clinical global impression rating scale .
a total of 40.8% of subjects reported at least 1 adverse event possibly associated with ramelteon use .
the adverse events reported varied considerably , the incidence of individual adverse events was low , and the frequencies of adverse events were similar at months 6 and 12.30 in contrast to zolpidem , ramelteon did not impair middle - of - the - night balance , mobility nor memory recall of elderly patients.60 there were no noteworthy changes in vital signs , physical examinations , clinical chemistry , hematology , nor urinalysis values .
endocrine values remained within the normal range throughout treatment , although consistent statistically significant decreases in free thyroxine ( in adults ) and free testosterone ( in older men ) were detected .
the duration of menses increased by approximately 1 day.30 in a double - blind , placebo - controlled trial of adults ( 1845 years ) with chronic insomnia , the effects of nightly 16 mg doses for 6 months of either ramelteon or placebo on endocrine function were evaluated.73 there were no consistent statistically significant differences between treatments on measures of thyroid function ( total or free thyroxine , tsh , total t3 ) , adrenal function ( am cortisol and acth ) , nor on most reproductive endocrine measures [ lh , fsh , estradiol ( women ) , total and free testosterone ( men ) ] .
prolactin concentrations were increased overall in women in the ramelteon group compared with placebo ( p = 0.003 ) . however , no clinical effects of elevated prolactin were reported .
average menstrual cycle length , duration of menses , and ovulation probability did not differ between groups.73 objective criteria in relation to metabolism , other diseases , hepatotoxicity , etc .
have also been investigated by takeda pharmaceuticals , with relevant testing showing that ramelteon clearly met the safety requirements which had been fundamental for approval by the fda .
nevertheless , it can not be overemphasized that mt1 and mt2 receptors are also located outside the scn and do not only regulate the circadian pacemaker.74 additional effects via these receptors have to be expected , eg , in cerebral vasomotor control , in immunomodulation , and other hormonal systems , including those involved in reproduction .
reasons for concern in this regard have been discussed elsewhere,14,18,32,75 and may become especially relevant for long - term treatment with the drug .
one final point of concern relates to the possible mutagenic and carcinogenic potential of ramelteon . according to the information provided by takeda,76 the no - effect level for induction of hepatic tumors in male mice was only three times the concentration of the metabolite m - ii measured after the therapeutic dose .
moreover , micronuclei formations were observed in chinese hamster lung cells after metabolic activation.76 the same information sheet mentions no mutagenicity in the ames test , but does not refer in this case to metabolic activation , which should also be routinely done with this assay .
it seems advisable that toxicity studies should be continued with ramelteon and its metabolites , in particular , m - ii , which attains concentrations more than an order of magnitude higher than the parent compound and which is much more slowly removed from the circulation.7 in summary , the suitability of ramelteon for longterm treatment requires further substantiation . with good reason , wurtman critically noted the paucity of available information on extended treatment with ramelteon.77 for the present , the drug should be cautiously prescribed , and only for short - term treatment .
while ramelteon appears to be safe for short - term treatment , a major question for future scientific investigation is whether ramelteon is safe for extended therapeutic use .
moreover , its applicability in older individuals , including those with age - related diseases , requires further investigation . in this context
, we would like to draw attention to the fact that mt1 and mt2 receptors are not only present in the scn , but are widely distributed throughout the body .
it seems important to know the consequences of desensitization of these receptors in the cerebral vascular system , in leukocytes and in peripheral organs , especially if ramelteon should cause longer lasting receptor downregulation compared with melatonin .
should this phenomenon occur , it could be a factor of concern for cerebral vascular tone and immune functions , especially in elderly people after longterm application .
other melatonergic agonists , such as agomelatine ( servier ) and tasimelteon ( vanda ) , are now on the market or are in the process of being approved by the american fda and other non - us regulatory bodies .
moreover , circadin ( neurim ) , a slow release preparation of melatonin has been approved by emea ( the european medicines agency , london ) for use in elderly patients with sleep disorders . a final important point to be considered
is that melatonin - like compounds generally display a modest sleep inducing effect , quite mild as compared to bzp .
certainly because of their long established availability in the marketplace , and also due to the lack of new alternative insomnia treatments , sleeping pills
this is a product characteristic which agents in the family of melatonergic compounds do not share , and , in terms of their actions , will never accomplish.78 therefore an emphasis on the fairly benign side effect profile ( its lack of negative effects , eg , addiction , dependence , etc . )
this is particularly relevant in view of the complications of benzodiazepines , which are well known to a major portion of insomnia sufferers .
preclinical ( rats and monkeys ) and clinical evidence suggest that ramelteon is a good candidate of choice and a safe hypnotic drug for clinical use in chronic primary insomnia .
it has been shown to reduce the latency for sleep onset and to increase the tst in all the clinical studies undertaken . during treatments lasting several weeks ,
the reported incidence of adverse effects with ramelteon has been similar to that of placebo . in all clinical studies carried out up to the present time , there have been no reports that ramelteon is associated with any physical dependence or abuse liability issues .
the hypnotic and chronobiotic actions of ramelteon are attributed to its effects on g potein - coupled melatonergic receptors present in the scn .
ramelteon s effectiveness in promoting phase advances of sleep / wake rhythms in humans has also been demonstrated , thus suggesting that it has potential therapeutic value not only in primary insomnia but also in crsd .
in addition , adverse drug effects such as withdrawal and rebound effects , drug effects on learning and memory , impaired motor co - ordination , and its abuse potential appear to be minimal.28,51,79 | ### Summary:
: ramelteon is a tricyclic synthetic analog of melatonin that acts specifically on mt1 and mt2 melatonin receptors .
ramelteon is the first melatonin receptor agonist approved by the food and drug administration ( fda ) for the treatment of insomnia characterized by sleep onset difficulties .
ramelteon is both a chronobiotic and a hypnotic that has been shown to promote sleep initiation and maintenance in various preclinical and in clinical trials .
the efficacy and safety of ramelteon in patients with chronic insomnia was initially confirmed in short - term placebo - controlled trials .
these showed little evidence of next - day residual effects , withdrawal symptoms or rebound insomnia .
other studies indicated that ramelteon lacked abuse potential and had a minimal risk of producing dependence or adverse effects on cognitive or psychomotor performance . a 6-month placebo - controlled international study and a 1-year open - label study in the usa demonstrated that ramelteon was effective and well tolerated .
other potential off - label uses of ramelteon include circadian rhythm sleep disorders such as shift - work and jet lag . at the present time
the drug should be cautiously prescribed for short - term treatment only . |
<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:
: arterial cannulation is often required during anesthesia and critical care and provides valuable hemodynamic information and convenient access to arterial blood sampling without causing additional patient discomfort .
1,2 the radial artery is a common site for such invasive cannulation during major surgery due to its anatomical accessibility , ease of cannulation , and relatively low rate of complications because of high collaterality from the neighboring ulnar artery .
3,4 vasoreactivity is affected by hypertension , hypercholesterolemia , hyperglycemia , and diabetes mellitus ( dm).5 dm is associated with endothelial dysfunction , enhanced contractile response , and impaired vasorelaxation in response to clinically relevant vasoconstrictors and external stimuli , such as arterial cannulation.6,7 the condition also causes arterial rigidity and increases peripheral vascular resistance , resulting in reduced blood flow , even when individuals have no apparent peripheral artery disease.8 although many studies have explored changes in radial artery vasoreactivity due to external stimuli and underlying conditions such as dm , limited information is available regarding dm 's effects on the ulnar artery after cannulation .
thus , to determine whether dm alters ulnar artery 's vasoreactivity to compensate any reduction of radial arterial flow , we evaluated and compared serial doppler patterns of ulnar artery as well as radial artery after radial artery cannulation in patients with and without dm under general anesthesia .
the human study protocol was approved by the institutional review board of severance hospital , yonsei university health system ( irb # 4 - 2013 - 0209 ) and was registered at http://clinicaltrials.gov ( registration # nct01897857 ) .
we obtained written informed consent from every patient in our study , which included 40 non - dm patients and 40 dm patients aged 20 to 60 years .
all patients were classified as either physical status iii or iv according to the american society of anesthesiologists and were scheduled for elective kidney transplantation which was to be performed under general anesthesia .
we excluded patients with known coagulopathy , signs of inflammation at the intended cannulation site , insufficient compensatory blood flow from the ulnar artery , or cannulation at an alternate site due to previous failed cannulation attempts .
the wrist joint of each patient was extended up to 45 on a wrist board as described in a study by mizukoshi et al .
9 we selected the cannulation position where the most prominent radial artery pulsation around the radial styloid process occurred . using b - mode ultrasound , we placed the probe axially 1 cm proximal to the marked point to measure the anterior - posterior internal diameter of the radial and ulnar arteries .
we then perpendicularly placed the probe to obtain a circular image of the artery ( figure 1a , 2a ) .
we measured the peak systolic velocity ( psv ) , end - diastolic velocity ( edv ) , resistance index ( ri , ri = [ psv - edv]/psv ) , and mean volume flow ( mvf ) directly from a longitudinal duplex doppler spectral waveform with an angle correction of 60 ( figure 1b , 2b ) .
we collected transverse sections of the radial artery proximal to the presumed puncture site to obtain maximal diameter measurements and clear visualization of the arteries ' internal lumen .
measurements were taken at five different time points : before anesthesia ( t0 ) ; 5 min after anesthesia but before cannulation ( t1 ) ; immediately after radial artery cannulation ( t2 ) ; 20 min after catheter removal ( t3 ) ; and 24 h after catheter removal ( t4 ) . at each time point , we measured hemodynamic parameters three times consecutively and calculated the mean values .
when the radial artery diameter decreased by more than 20% of the pre - cannulation diameter , we noted cannulation - induced vasospasm .
10 ultrasonographic measurements were obtained using a logiqe instrument ( ge healthcare , wauwatosa , wi , usa ) with a linear probe ( 12l - rs , 8 - 13 mhz ) by a single experienced operator .
general anesthesia was induced with 0.51 g / kg remifentanil and 1.52 mgkg propofol , and tracheal intubation was performed after administration of 0.8 mg / kg rocuronium bromide .
anesthesia was maintained with 0.050.15 g / kg / min continuous infusion of remifentanil and 5.0 - 5.5% end - tidal desflurane in 50% o2/air . after successful intubation and completion of the doppler measurement ( t1 ) , radial artery cannulation
was performed by a single designated anesthesiologist using a uniform 20-g cannula ( biosafety iv catheter , 1.1 48 mm , flow 55 ml / min ( sewon medical co. , cheonan , korea ) ) via the palpation - guided simple catheter over needle technique , of which designated anesthesiologist was more proficient at , compared to rather unaccustomed ultrasound - guided method .
the number of cannulation attempts was limited to two trials ; patients who experienced two failed cannulation attempts were excluded from the study .
we minimized the frequency and amount of manual flushing of the arterial cannula with non - heparinized fluid and avoided unnecessary manipulation or stimulation of the arterial walls and cannula .
sample size calculations were based on arterial diameter changes reported by a previous study , 11 in which the standard deviation of the radial artery diameter was 0.45 mm . therefore , 36 subjects in each group ( dm or non - dm ) were required to detect a 0.3-mm difference in the radial artery diameters between the two groups at post - cannulation period using a two - sided of 5% and power of 80% . to account for a potential 10% dropout rate in each group ,
statistical analysis of patient data was performed using pasw statistics 20 ( spss inc . , chicago , il , usa ) and sas software version 9.2 ( sas institute inc . ,
patient characteristics were analyzed using an independent t - test , and categorical variables were evaluated using a chi - squared test or fisher 's exact test when appropriate .
values are reported as means standard deviation ( sd ) , median ( interquartile range , iqr ) or as numbers of patients ( % ) .
comparison of changes in hemodynamic characteristics to their corresponding baseline values were performed with linear mixed models with post - hoc tests using bonferroni correction .
nonparametric repeated measure variables were analyzed using the friedman test or mann - whitney u test .
sample size calculations were based on arterial diameter changes reported by a previous study , 11 in which the standard deviation of the radial artery diameter was 0.45 mm .
therefore , 36 subjects in each group ( dm or non - dm ) were required to detect a 0.3-mm difference in the radial artery diameters between the two groups at post - cannulation period using a two - sided of 5% and power of 80% . to account for a potential 10% dropout rate in each group ,
statistical analysis of patient data was performed using pasw statistics 20 ( spss inc . , chicago , il , usa ) and sas software version 9.2 ( sas institute inc . ,
patient characteristics were analyzed using an independent t - test , and categorical variables were evaluated using a chi - squared test or fisher 's exact test when appropriate .
values are reported as means standard deviation ( sd ) , median ( interquartile range , iqr ) or as numbers of patients ( % ) .
comparison of changes in hemodynamic characteristics to their corresponding baseline values were performed with linear mixed models with post - hoc tests using bonferroni correction .
nonparametric repeated measure variables were analyzed using the friedman test or mann - whitney u test .
forty non - dm and 40 dm patients were recruited between july 2013 and november 2015 , all of whom completed the study .
demographic and baseline clinical characteristics of 40 non - dm and 40 dm human patients are presented in table 1 .
patients with dm showed a higher incidence of accompanied hypertension than non - dm patients ( 98% vs. 78% , respectively ; p = 0.021 ) and had , on average , experienced dm for 11 years .
we observed no significant intergroup differences with respect to demographics , presence of atherosclerosis , medications , surgery - related data , or arterial cannulation - related clinical variables . despite the increased incidence of hypertension in dm patients ,
mean blood pressures ( mbp ) were comparable between the two groups ( table 2 ) .
such likewise were also noted at 2 days before and after surgery during which the effect of surgery - related anxiety or postoperative pain had been minimized ( non - dm vs. dm ; 91 vs. 91 mmhg , p = 0.973 at 2 days before surgery ; 99 vs. 98 mmhg , p = 0.571 at 2 days after surgery ) .
in addition , baseline radial and ulnar values of internal diameter , psv , edv , ri , and mvf did not differ significantly between non - dm and dm patients ( figure 3 , 4 ) .
radial artery diameter increased in non - dm patients after anesthesia and persisted after radial artery cannulation ( figure 3a ) .
however , the diameter decreased immediately after catheter removal , resulting in similar diameters between the two groups , although a greater radial diameter was again seen in non - dm patients 24 h after catheter removal .
radial artery mvf , determined by time- averaged mean velocity and internal diameter of the corresponding artery , in non - dm patients more than doubled after anesthesia and cannulation , returned to baseline value after catheter removal in radial artery , and redoubled 24 h after catheter removal ( figure 3b ) .
in contrast , although we observed increased radial artery mvf in dm patients , the values were not significantly different from baseline data .
the ri of non - dm patients decreased by 20% and 16% after anesthesia and cannulation , respectively ( figure 3c ) , while dm patients experienced a more modest decrease of 14% after anesthesia and 16% after cannulation .
ulnar artery mvf in non - dm patients was 3.4 times higher after anesthesia and cannulation compared to baseline values .
we also observed a 29% increase in ulnar artery diameter in these patients due to compensatory dynamics from the interrupted radial artery blood flow resulting from cannulation ( figures 4a , 4b ) .
we saw similar , but more subtle , trends in the dm patients , in which compensatory changes increased ulnar artery mvf to 2.7 times higher than baseline and caused a 5.6% increase in internal diameter .
ulnar artery ri after anesthesia significantly decreased in both non - dm and dm patients , who experienced 21% and 14% reduction of baseline values , respectively .
however , we saw no significant difference in ri between the two groups with respect to cannulation and catheter removal ( figure 4c ) .
no patients reported hematoma formation , thrombosis , cannulation - related pain , or sensory changes before hospital discharge .
our results demonstrate the impact of underlying dm on arterial vasoreactivity after simple catheter cannulation during surgery .
specifically , we noted that patients with dm were temporally unsuccessful in showing adaptive vasoreactivity of the radial and ulnar arteries after radial artery cannulation under general anesthesia .
fortunately , the internal diameter and blood flow of both arteries returned to near - baseline levels in all patients 24 h after removal of their radial artery catheter . due to easy accessibility and low rate of associated complications ,
the radial artery is favored in various clinical procedures , such as for a bypass conduit during coronary artery bypass graft ( cabg ) surgery,12,13 as the site of cardiac catheterization in coronary angiography,14 and as the route of cannulation for continuous monitoring of arterial pressure.2 in addition , the artery 's vascular response to external stimuli ( vasoreactivity ) has been investigated extensively.13,15 - 17 radial artery harvest has shown mild reduction in digital perfusion and complementary increase in ulnar artery diameter and flow velocity with no clinical sequelae or compromised hand function.18,19 after catheterization for coronary angiography access , the artery may exhibit reduced lumen density due to wall injuries after cannulation.20,21 in contrast to the immense amount of information available regarding radial artery vasoreactivity with respect to vascular surgery and coronary intervention , very few studies have explored changes in radial artery related to cannulation access for real - time blood pressure monitoring .
10,22 similarly , although dm strongly influences vasoreactivity,23,24 its specific impact on vasoreactivity after simple arterial cannulation for invasive blood pressure monitoring is not well - studied .
the procedure is widely adopted , yet still carries a high risk of complications , especially in patients with atherosclerosis - related risk factors . the frequency of previously reported vascular complications after radial artery cannulation ranges from 1.5% to 88% , 2 which widely varies from temporary spasm to distal limb ischemia .
other possible complications include bleeding ( 0.5% ) , hematoma ( 14.4% ) , pseudoaneurysm ( 0.09% ) , infection ( 0.72% ) , and sepsis ( 0.13% ) .
2,3 in diabetic patients , the incidence of complications is higher as evidenced by histomorphological and molecular characterization of the arteries .
13,25 hyperglycemia influences vasoreactivity and vessel integrity , which are also affected by the balance between enos ( endothelial nos ) and endothelin .
13,26 endothelium - associated enos can generate nitric oxide ( no ) , which regulates vascular tonus according to blood flow demand , 27 while the vasoactive peptide endothelin contributes to vasoconstriction in vascular smooth muscle cells .
moreover , insulin resistance found in patients with dm impairs no synthesis and trapping of no reactive oxygen species which can decrease no bioavailability.28 vasoreactivity and the consequent alteration of vessel diameter are known collectively as arterial remodeling.29 in studies focused on such vascular response , patients with hyperglycemia and dm fail to exert compensational arterial changes after exposure to an external stimulus,23,28,30 and may deter rapid recovery of patients.6,31 similarly , we observed that dm patients showed little or no changes in radial artery internal diameter , blood flow , or ri compared to baseline values , while significant changes in such arterial hemodynamics of non - dm patients occurred probably due to the changes in vasoactive balance , sympathetic tone , and external stimuli throughout perioperative period .
the ulnar artery , which often provides active compensation after neighboring radial artery cannulation , also showed only subtle changes in its arterial hemodynamics among dm patients , indicating less compensation for decreased blood flow from damaged radial artery .
per our study hypothesis , which focused on radial artery cannulation and consequential changes in the ulnar artery , we observed significant changes in arterial diameter , blood flow , and ri , possibly due to reduced sympathetic tone after anesthesia .
moreover , as our study had focused on the changes in vascular reactivity followed by relatively lesser dealt simple arterial cannulation , such distinguishing changes in vasoreactivity according to underlying dm can also be applied in better understanding of patients ' outcomes in other surgical procedures , such as cabg , and for cardiac catheterization in coronary angiography .
first , in order to avoid unnecessary arterial cannulation and only to recruit those who actually require arterial cannulation for invasive blood pressure monitoring during surgery , this study enrolled those who were scheduled for kidney transplantation .
such group of patients could inevitably affect the vasoreactivity of the vessels due to the arteriopathy related to primary renal disease .
second , intergroup differences in underlying hypertension and dm prevalence could have affected endothelial characteristics , as these conditions accelerate dm - associated microvascular and macrovascular complications .
although neither dm nor non - dm patients showed significant differences with respect to atherosclerosis incidence , the possibility that non - dm patients may have other atherosclerosis - related systemic diseases should not be overlooked .
lastly , we could increase accuracy of the ultrasound measurements only so much , although we maximized its utility by taking multiple measurements by one well - trained sonographer for all scans .
alternative high - accuracy methods , such as arteriography , plethysmography , and flow - mediated dilation , are available but do not provide the same ease and accessibility as sonography .
in conclusion , diabetic patients lack ulnar artery 's vasoreactivity to compensate for sudden changes in radial arterial flow following radial artery cannulation under general anesthesia . | ### Summary:
: background : endothelial dysfunction associated with diabetes mellitus ( dm ) may influence arterial vasoreactivity after arterial stimulus , such as cannulation , and cause changes in diameter and blood flow . despite the frequent use of arterial cannulation during anesthesia and critical care , little information is available regarding vasoreactivity of the radial and ulnar arteries and its influence on underlying dm.methods : forty non - dm and 40 dm patients , who required arterial cannulation during general anesthesia , were enrolled . using duplex doppler ultrasonography , we measured the patients ' arterial diameter , peak systolic velocity , end - diastolic velocity , resistance index , and mean volume flow of both arteries at five different time points.results : after radial artery cannulation , ulnar arterial diameter and blood flow did not significantly increase in dm group , as they did in non - dm group .
ulnar arterial resistance index significantly increased in both groups , but the degree of decrease in dm group was significantly less than non-dm.conclusion : ulnar artery 's ability to increase blood flow for compensating the sudden reduction of radial arterial flow in dm patients was significantly less than that in non - dm patients under general anesthesia .
such attenuated vasoreactivity of ulnar artery to compensate the reduced radial arterial flow may have to be considered in radial arterial cannulation for dm 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:
: chronic pelvic pain ( cpp ) is now widely acknowledged as a common problem with significant consequences for those diagnosed with this condition.1 although cpp can affect men and women , this article focuses on pelvic pain in women .
definitions of the condition are somewhat imprecise , but typically specify that the pain occurs in the lower abdominal area for at least 6 months , and is unrelated to menstruation , intercourse , or pregnancy.24 cpp in women can have many causes that often provide only a partial explanation for the subjective experience reported by the patient.3 these causes include endometriosis , pelvic inflammatory disease , and pelvic adhesions . a recent systematic review by latthe et al5 evaluated more than 60 potential risk factors for pelvic pain , and identified strong and consistent support for three key factors : the presence of pelvic pathology , history of abuse , and comorbid psychological conditions .
community - based studies estimate the prevalence of cpp to be between 15.8% and 25%.6,7 moreover , it is often debilitating , affecting a woman s personal relationships , ability to work , sexual functioning , and self - esteem.8,9 in recent years a number of guides to the management of this condition have been published10 and increasing clinical attention is being paid to the condition,11 with an emphasis on moving away from an organ - specific model of cpp to a broad biospychosocial understanding of this condition .
nevertheless , women often find the experience of clinical assessment and treatment unsatisfactory.12 qualitative studies reveal that many women with cpp feel misunderstood by their medical practitioners , who are perceived to not understand the extent or seriousness of their pain , and gave them the impression that the pain is all in my head.9 there are several possible reasons for this , including the inherent complexity of the condition.3 moreover , there are still considerable gaps in our knowledge about the condition , resulting in limited understanding of the profiles of women presenting to pelvic pain clinics .
an article on the profile of women with cpp by reiter13 focused on demographic factors and their medical history , rather than their psychological characteristics .
grace and zondervan2 also reported on the physical comorbidities of cpp , stating that 68.7% of women with cpp had experienced pain other than cpp and/or fatigue in the previous 12 months .
some authors including ghaly and chien3 and romao et al have reported on the high prevalence of depression , somatization disorders , and childhood sexual abuse in women with cpp.14 others have questioned whether there is a direct and specific link between childhood sexual abuse and cpp , emphasizing instead the relevance of more recent sexual trauma and the effects of re - victimization on the expression of cpp.1518 relatively few studies have focused on the psychological profiles of women with cpp .
exceptions include thomas et al18 and weijenborg et al.19 the fear - avoidance model of pain , commonly applied to musculoskeletal pain conditions , has also been found to be relevant to women with cpp.20 this study highlighted the importance of negative beliefs about the pain ( pain catastrophizing ) . a recent study by miller - matero et al21 reported on relationships between functioning pain and psychological variables , but this focused only on symptoms of anxiety and depression .
a study of illness perceptions in a clinic population highlighted the weak self - efficacy beliefs held by women with cpp , and their perception that their condition was confusing and perplexing.22 in general , the articles cited above focus either on broad issues , such as depression , or rather specific psychological aspects of pain ( eg , emotion suppression ) .
there is a lack of studies with good sample size that provide a more comprehensive profile of women presenting to specialist chronic pain clinics .
a better understanding of the psychological needs of women with cpp is essential for the planning of effective interventions and appropriate services .
therefore , the aim of this study was to address these shortcomings by describing the psychological profile of a representative sample of women presenting with cpp at a tertiary referral center .
we used a range of measures to capture pain experience , pain self - efficacy , thinking style , depression , anxiety , and sexual functioning that are important for treatment of this condition .
we hypothesized that women attending the clinic would experience high levels of anxiety and depression , and that higher scores on anxiety and depression measures would be associated with higher levels of pain interference , pain catastrophizing , and lower self - efficacy .
this study employed a questionnaire methodology with participants recruited from the chronic pelvic pain clinic ( cppc ) of the royal women s hospital , a public hospital situated in a metropolitan area of australia .
the clinic has a multidisciplinary team approach in which a pain specialist ( consultant anesthetist ) , clinical psychologist , physiotherapist , and social worker assist women in the treatment and management of their pain .
women were eligible to be included in the study if they were aged 18 years or older , were currently experiencing cpp , and attending the cppc .
diagnosis of cpp was made by the medical pain specialist in the clinic . from june 2008 to october 2014 , 185 consecutive new referrals attended the clinic , of whom 95% completed the questionnaires , resulting in a sample size of 175 .
all women attending their initial assessment at the cppc are asked to complete a series of questionnaires on arrival .
all participants gave written informed consent for their data to be used for research purposes , and then filled out the relevant documents .
the measures were selected with a view to identifying the nature and extent of the women s pain experience , as well as gathering data on a range of psychological factors known to be important to the experience and treatment of chronic pain . the brief pain inventory ( bpi ) ( short form)23 is a widely - used measure of pain and its interference with everyday life , comprising two subscales , namely the pain severity and pain interference subscales . for the former ,
participants were asked to rate their current pain intensity as well as their pain in the past 24 hours at its worst , least , and average by indicating on a 10-point likert scale where 0= no pain and 10 = pain as severe as you can imagine . on the pain interference
subscale participants indicated how their pain has affected their quality of life in several different domains ( eg , walking , relations with other people ) over the past 24 hours ( on a 10-point likert scale where 0= does not interfere and 10 = completely interferes ) .
the bpi has been found to have acceptable internal consistency ( cronbach s 0.85 ) and was able to detect improvement over time in chronic pain patients receiving treatment from a pain - management clinic.23 the hospital anxiety and depression scale ( hads)24 was used as a measure of anxiety and depression symptoms .
this 14-item scale is used as a screening and severity measure for anxiety and depression in medical outpatients .
the hads has well established psychometric properties ( cronbach s 0.80 ) and was specifically designed for non - psychiatric medical patients.24 a score of 07 is considered in the normal range , 810 indicates mild anxiety or depression , scores above eleven are indicative of moderate anxiety or depression , and scores > 15 indicate severe anxiety or depression . the pain self - efficacy questionnaire (
pseq)25 was used to ask participants to rate how confidently they could perform a range of listed activities despite their pain .
participants answer on a 7-point likert scale where 0= not at all confident and 6= completely confident .
scores range from 060 , with higher scores indicating greater self - efficacy , with a mean score of 25.9 reported in a sample of patients with back pain .
the pseq has been widely used in studies examining individuals with chronic pain and has been shown to have good internal consistency ( cronbach s 0.93).26 the coping strategies questionnaire ( csq)27 is a 50-item measure of coping in chronic pain patients .
participants answer on a 7-point likert scale where 0= never and 6= always in response to items such as ,
i feel my life is nt worth living and i feel like i ca nt go on .
thus , total scores can range from 036 , with higher scores indicating more dysfunctional attitudes .
the female sexual function index ( fsfi)28 is a 36-item scale assessing six domains of sexual functioning , including desire , orgasm , and pain assessed over the preceding 4 weeks on a 5-point scale .
participants answered three questions from the original scale : two questions with respect to discomfort of pain during and after penetration , and one assessing the degree of discomfort during or after penetration .
statistical analysis was carried out using spss version 22 ( ibm corporation , armonk , ny , usa ) to calculate means of all the measures , and correlations between key variables .
composite scores were calculated using the 20% missing mean replacement rule for the raw item scores on the measures.29 once scaled scores were calculated , a missing values analysis was undertaken , and determined these to be missing at random ; therefore the remaining data for composite scores could be imputed using the expectation - maximization technique .
this study employed a questionnaire methodology with participants recruited from the chronic pelvic pain clinic ( cppc ) of the royal women s hospital , a public hospital situated in a metropolitan area of australia .
the clinic has a multidisciplinary team approach in which a pain specialist ( consultant anesthetist ) , clinical psychologist , physiotherapist , and social worker assist women in the treatment and management of their pain .
women were eligible to be included in the study if they were aged 18 years or older , were currently experiencing cpp , and attending the cppc .
diagnosis of cpp was made by the medical pain specialist in the clinic . from june 2008 to october 2014 , 185 consecutive new referrals attended the clinic , of whom 95% completed the questionnaires , resulting in a sample size of 175 .
all women attending their initial assessment at the cppc are asked to complete a series of questionnaires on arrival .
all participants gave written informed consent for their data to be used for research purposes , and then filled out the relevant documents .
the measures were selected with a view to identifying the nature and extent of the women s pain experience , as well as gathering data on a range of psychological factors known to be important to the experience and treatment of chronic pain . the brief pain inventory ( bpi ) ( short form)23 is a widely - used measure of pain and its interference with everyday life , comprising two subscales , namely the pain severity and pain interference subscales . for the former ,
participants were asked to rate their current pain intensity as well as their pain in the past 24 hours at its worst , least , and average by indicating on a 10-point likert scale where 0= no pain and 10 = pain as severe as you can imagine . on the pain interference
subscale participants indicated how their pain has affected their quality of life in several different domains ( eg , walking , relations with other people ) over the past 24 hours ( on a 10-point likert scale where 0= does not interfere and 10 = completely interferes ) .
the bpi has been found to have acceptable internal consistency ( cronbach s 0.85 ) and was able to detect improvement over time in chronic pain patients receiving treatment from a pain - management clinic.23 the hospital anxiety and depression scale ( hads)24 was used as a measure of anxiety and depression symptoms .
this 14-item scale is used as a screening and severity measure for anxiety and depression in medical outpatients .
the hads has well established psychometric properties ( cronbach s 0.80 ) and was specifically designed for non - psychiatric medical patients.24 a score of 07 is considered in the normal range , 810 indicates mild anxiety or depression , scores above eleven are indicative of moderate anxiety or depression , and scores > 15 indicate severe anxiety or depression . the pain self - efficacy questionnaire ( pseq)25 was used to ask participants to rate
participants answer on a 7-point likert scale where 0= not at all confident and 6= completely confident .
scores range from 060 , with higher scores indicating greater self - efficacy , with a mean score of 25.9 reported in a sample of patients with back pain .
the pseq has been widely used in studies examining individuals with chronic pain and has been shown to have good internal consistency ( cronbach s 0.93).26 the coping strategies questionnaire ( csq)27 is a 50-item measure of coping in chronic pain patients .
participants answer on a 7-point likert scale where 0= never and 6= always in response to items such as ,
i feel my life is nt worth living and i feel like i ca nt go on .
thus , total scores can range from 036 , with higher scores indicating more dysfunctional attitudes .
the female sexual function index ( fsfi)28 is a 36-item scale assessing six domains of sexual functioning , including desire , orgasm , and pain assessed over the preceding 4 weeks on a 5-point scale .
participants answered three questions from the original scale : two questions with respect to discomfort of pain during and after penetration , and one assessing the degree of discomfort during or after penetration .
statistical analysis was carried out using spss version 22 ( ibm corporation , armonk , ny , usa ) to calculate means of all the measures , and correlations between key variables .
composite scores were calculated using the 20% missing mean replacement rule for the raw item scores on the measures.29 once scaled scores were calculated , a missing values analysis was undertaken , and determined these to be missing at random ; therefore the remaining data for composite scores could be imputed using the expectation - maximization technique .
the mean age of the participants was 36 years ( standard deviation [ sd ] = 14 years , range : 1879 years ) .
over 75% of them had experienced pain for longer than 2 years , and 51.4% said they could associate a specific event with the pain , ranging from either a past trauma / surgery , to patterns following menstruation , intercourse , etc .
around half the women ( 49% ) deemed their cpp to be the worst pain they had ever experienced compared with a range of other sources of pain , including labor , surgery , and other chronic pains such as back pain and migraines .
scores on the bpi indicated a moderate degree of pain severity , with the mean of composite scores for overall pain severity derived from the four pain severity items being 5.55 ( sd = 2 ) .
the mean of composite scores for overall pain interference derived from the nine pain interference items was 5.72 ( sd = 2.47 ) .
table 1 reports mean interference for each of the activities measured by the bpi , and shows that enjoyment of life and mood were rated as most interfered with , and had the lowest spread in scores ( mean [ m ] = 6.61 , sd = 2.92 ; m = 6.34 , sd = 2.77 , respectively ) . interference with walking ability and appetite
received the lowest mean scores , and also the greatest dispersion ( m = 4.76 , sd = 3.32 ; m = 4.40 , sd = 3.23 , respectively ) .
this group of women experienced significant symptoms of depression and anxiety as measured by the hads .
only 22.9% of women scored below the cut - off of eight that suggests the presence of mild symptoms .
twenty - four percent experienced mild anxiety ( scores ranging from 810 ) , 40% moderate anxiety ( 1115 ) , while 13.1% experienced severe anxiety ( 1621 ) . on the hads depression scale , the mean score was 8.07 ( sd = 4.45 ) , lower than the mean anxiety score and almost half the women ( 46.9% ) scored below the cut - off of eight . of those who did endorse symptoms of depression
, 26.2% scored in the mild range , ( 810 ) , 22.3% in the moderate range ( 1115 ) , and 4.6% experienced severe depression ( 1621 ) .
there was a significant positive correlation of hads depression subscale scores with age ( r=0.176 , p<0.05 ) .
women in this study reported low levels of pain self - efficacy , with the mean scores on the pseq being 23.35 .
these show that women were least confident in coping without medication , and had the highest confidence in being able to do household chores and doing some form of work .
another measure of beliefs about pain is the catastrophizing subscale of the csq , and in this study responses to the csq catastrophizing subscale were approximately normally distributed around the mean .
the average catastrophizing score was 20.96 , with the mean score for individual items being 3.5 ( sd = 1.4 ) on a 7-point likert scale , indicating moderate catastrophizing , but with substantial variance among individuals .
i feel my life is nt worth living , with a mean response of 2.12 ( sd = 1.86 ) . on the other hand , the mean rating of the item
it s terrible and i feel it s never going to get better was 4.29 ( sd = 1.58 ) on a likert scale , indicating high catastrophizing about the long - term prognosis of their cpp . the final measure used to profile the functioning of the participants was the female sexual function scale ( fsfi ) .
data from this measure showed that in the previous week , 46% of the sample had not attempted intercourse , and of those who had , 50% experienced pain or discomfort during vaginal penetration almost always or always , and 75% experienced pain / discomfort at least half the time .
pain was experienced after penetration almost always or always by 43% of the women and at least half the time by 72% of the participants .
the discomfort or pain was at least moderate to severe for 83% of the sample , and high or very high for 58% of the sample who had attempted intercourse .
we were also interested to know how the observed measures related to each other , and examined this by means of correlational analyses .
pearson s two - tailed correlations were employed . taking symptoms of depression and anxiety as the primary reference variables we found that scores of the hads anxiety subscale and hads depression subscale were significantly correlated with all other key study variables ( the bpi , csq , and pseq ) .
not surprisingly , the highest correlations were between the anxiety and depression subscales of the hads ( 0.606 ) , and between pain severity and pain interference ( 0.648 ) .
the mean age of the participants was 36 years ( standard deviation [ sd ] = 14 years , range : 1879 years ) .
over 75% of them had experienced pain for longer than 2 years , and 51.4% said they could associate a specific event with the pain , ranging from either a past trauma / surgery , to patterns following menstruation , intercourse , etc .
around half the women ( 49% ) deemed their cpp to be the worst pain they had ever experienced compared with a range of other sources of pain , including labor , surgery , and other chronic pains such as back pain and migraines .
scores on the bpi indicated a moderate degree of pain severity , with the mean of composite scores for overall pain severity derived from the four pain severity items being 5.55 ( sd = 2 ) .
the mean of composite scores for overall pain interference derived from the nine pain interference items was 5.72 ( sd = 2.47 ) .
table 1 reports mean interference for each of the activities measured by the bpi , and shows that enjoyment of life and mood were rated as most interfered with , and had the lowest spread in scores ( mean [ m ] = 6.61 , sd = 2.92 ; m = 6.34 , sd = 2.77 , respectively ) . interference with walking ability and appetite
received the lowest mean scores , and also the greatest dispersion ( m = 4.76 , sd = 3.32 ; m = 4.40 , sd = 3.23 , respectively ) .
this group of women experienced significant symptoms of depression and anxiety as measured by the hads .
only 22.9% of women scored below the cut - off of eight that suggests the presence of mild symptoms .
twenty - four percent experienced mild anxiety ( scores ranging from 810 ) , 40% moderate anxiety ( 1115 ) , while 13.1% experienced severe anxiety ( 1621 ) . on the hads depression scale , the mean score was 8.07 ( sd = 4.45 ) , lower than the mean anxiety score and almost half the women ( 46.9% ) scored below the cut - off of eight . of those who did endorse symptoms of depression
, 26.2% scored in the mild range , ( 810 ) , 22.3% in the moderate range ( 1115 ) , and 4.6% experienced severe depression ( 1621 ) .
there was a significant positive correlation of hads depression subscale scores with age ( r=0.176 , p<0.05 ) .
women in this study reported low levels of pain self - efficacy , with the mean scores on the pseq being 23.35 .
these show that women were least confident in coping without medication , and had the highest confidence in being able to do household chores and doing some form of work .
another measure of beliefs about pain is the catastrophizing subscale of the csq , and in this study responses to the csq catastrophizing subscale were approximately normally distributed around the mean .
the average catastrophizing score was 20.96 , with the mean score for individual items being 3.5 ( sd = 1.4 ) on a 7-point likert scale , indicating moderate catastrophizing , but with substantial variance among individuals .
i feel my life is nt worth living , with a mean response of 2.12 ( sd = 1.86 ) . on the other hand , the mean rating of the item
it s terrible and i feel it s never going to get better was 4.29 ( sd = 1.58 ) on a likert scale , indicating high catastrophizing about the long - term prognosis of their cpp .
the final measure used to profile the functioning of the participants was the female sexual function scale ( fsfi ) .
data from this measure showed that in the previous week , 46% of the sample had not attempted intercourse , and of those who had , 50% experienced pain or discomfort during vaginal penetration almost always or always , and 75% experienced pain / discomfort at least half the time .
pain was experienced after penetration almost always or always by 43% of the women and at least half the time by 72% of the participants .
the discomfort or pain was at least moderate to severe for 83% of the sample , and high or very high for 58% of the sample who had attempted intercourse .
we were also interested to know how the observed measures related to each other , and examined this by means of correlational analyses .
taking symptoms of depression and anxiety as the primary reference variables we found that scores of the hads anxiety subscale and hads depression subscale were significantly correlated with all other key study variables ( the bpi , csq , and pseq ) .
not surprisingly , the highest correlations were between the anxiety and depression subscales of the hads ( 0.606 ) , and between pain severity and pain interference ( 0.648 ) .
the aim of this study was to provide a rounded profile of the psychological symptoms and functioning of women attending a tertiary treatment center for cpp .
our findings confirm previous evidence for high levels of psychological distress and functional impairment associated with this condition,21 and extend these findings by including measures that are highly relevant to treatment planning , such as thinking styles and pain self - efficacy .
our findings confirm the need to move away from organ - focused approaches to pain , and use integrated models of pain to understand this condition.10,11 consistent with previous work , levels of anxiety symptoms were higher than depressive symptoms , and 53% of the sample experienced either moderate or severe levels of anxiety symptoms.14,22 anxiety scores on the hads anxiety subscale were strongly correlated with pain catastrophizing , highlighting the interconnections between cognitive and emotional aspects of pain .
depressive symptoms were less common overall , but more than a quarter of the sample ( 26.9% ) experienced depressive symptoms in the moderate or severe range .
this is lower than the prevalence of 86% reported by lorencatto et al30 in a study utilizing the beck depression inventory , but similar to the prevalence of 21% reported by poleshuck et al31 and almost identical to the prevalence of 25.7% reported by miller - matero et al , who also used the hads.21 as the hads was designed for use in hospital outpatient populations it is possible that this provides a more accurate picture than the beck depression inventory , which includes a number of potentially confounding somatic items .
high levels of depression and anxiety are well - established in clinical pain populations , and the reasons for this are complex and varied.32 one view is that living with persistent pain and the limitations that this may impose leads to low mood,33 but increasing attention is now being paid to biological pathways and neurotransmitters that are shared by pain and depression , such as dopamine in the mesolimbic pathway.34 yet another view proposes that the high prevalence of depression is related to the experiences of childhood neglect , physical and sexual abuse , or domestic violence that are common in the histories of women with cpp.18 perhaps equally important from the clinical point of view is the very strong association between symptoms of depression and a range of key variables known to be associated with greater functional impairment and poorer treatment outcomes.14,33 this study found that , depression was strongly correlated with lower pain self - efficacy and with catastrophic thinking .
these are cross - sectional data , so causality can not be attributed , but it is highly likely that there is a bi - directional interplay between affective state and pain beliefs , as suggested by banks and kerns.35 this means that treatment of cpp must address both the symptoms of anxiety and depression and the maladaptive thinking and beliefs with which they are associated .
indeed , it is concerning that the majority of women in this study reported weak self - efficacy , as holding stronger self - efficacy beliefs is positively associated with use of more active coping behaviors in people with chronic pain .
for example , jensen et al found that self - efficacy beliefs were strongly related to participants reported coping strategies.36 interestingly , the authors also found that the participants expectancies regarding coping were only weakly related to actual coping skills and practices , leading them to conclude that it may be more effective for pain management programs to promote behavior change , rather than attitude change.36 although the women in the current study endorsed moderate , rather than severe , levels of catastrophic thinking , there was wide variation in the distribution of scores on this scale , and consistent with prior studies,37 a very strong correlation with depression scores was found .
this is significant for a number of reasons : experiencing both low mood and negative views of pain and its consequences are likely to pose a double risk for poor outcomes .
depression in those with chronic pain is associated with greater functional impairment and reductions in quality of life,13,38 and catastrophic thinking has been linked to poorer outcomes in those with knee osteoarthritis.39 research examining the role of these factors in pelvic pain is lacking , and there is an urgent need for studies to examine these factors prospectively . taken together with previous work indicating that women with cpp frequently believe that they have little control over their pain , which they furthermore find perplexing , and believe will be chronic and impairing,22 it is clear that the effective treatment of cpp must pay attention to the illness perceptions and beliefs that women hold , which would include a thorough evaluation of illness perceptions , providing education about pain , and , where appropriate , challenging unhelpful or inaccurate perceptions and actively linking this to behavior change .
an important aspect of this is to improve self - efficacy and decrease overly negative cognitions .
one approach to this is for physiotherapists to empower the patient s bodily experience through techniques such as graded exposure.40 data from other multidisciplinary clinics also highlight the importance of integrating the physical and psychological aspects of treatment , including increasing physical activity.11 one of the strengths of this study was the very high participation rate : 95% of consecutive referrals to the cppc agreed to participate .
together with the large sample size of 175 , we can be confident that these data are representative of the women who attend this tertiary clinic .
we can not , of course , extrapolate from these women to community - based , nonclinical samples , nor were we able to compare our sample with individuals with other types of pain . nevertheless , these findings share some similarities with other studies based on clinical populations , for example , those of miller - matero et al.21 a further strength of the study was the use of a carefully selected range of measures . these measures are not exhaustive ,
however there are aspects of pain we could have made enquiry about , for example , the presence of trauma and re - victimization symptoms , which are known to be associated with cpp,18 locus of control , emotional suppression , and work role functioning , to name but a few .
our measures were also all based on self - report , which is an intrinsic challenge in assessing subjective experiences , such as pain .
in addition , our database did not provide information on other pain experienced by our participants .
nevertheless , these measures provide a more rounded picture of women presenting to a tertiary referral center than has hitherto been available , and is unique in the australian context .
one important limitation is the cross - sectional nature of our data , which are only available from one time - point .
we can not therefore establish the causal pathways between pain , anxiety , depression , and dysfunctional beliefs . on the basis of previous research
, however , we have good reason to believe that they are reciprocal , and need to be taken into account in treatment planning.11,20 future work should seek to follow women up after they have completed treatment in order to ascertain the changes that may or may not result from treatment .
we have attempted to do this in our clinic , but had very low rates of retention and data completion .
one of the strengths of this study was the very high participation rate : 95% of consecutive referrals to the cppc agreed to participate . together with the large sample size of 175
, we can be confident that these data are representative of the women who attend this tertiary clinic .
we can not , of course , extrapolate from these women to community - based , nonclinical samples , nor were we able to compare our sample with individuals with other types of pain . nevertheless , these findings share some similarities with other studies based on clinical populations , for example , those of miller - matero et al.21 a further strength of the study was the use of a carefully selected range of measures .
these measures are not exhaustive , however there are aspects of pain we could have made enquiry about , for example , the presence of trauma and re - victimization symptoms , which are known to be associated with cpp,18 locus of control , emotional suppression , and work role functioning , to name but a few .
our measures were also all based on self - report , which is an intrinsic challenge in assessing subjective experiences , such as pain .
in addition , our database did not provide information on other pain experienced by our participants .
nevertheless , these measures provide a more rounded picture of women presenting to a tertiary referral center than has hitherto been available , and is unique in the australian context .
one important limitation is the cross - sectional nature of our data , which are only available from one time - point .
we can not therefore establish the causal pathways between pain , anxiety , depression , and dysfunctional beliefs . on the basis of previous research
, however , we have good reason to believe that they are reciprocal , and need to be taken into account in treatment planning.11,20 future work should seek to follow women up after they have completed treatment in order to ascertain the changes that may or may not result from treatment .
we have attempted to do this in our clinic , but had very low rates of retention and data completion .
we have shown that in a large , representative sample of women attending a tertiary treatment center for cpp participants experienced high levels of anxiety and depression , high levels of pain severity and interference over long periods of time ( three quarters of the women in our study had pain for more than 2 years ) .
this was associated with low levels of pain self - efficacy and moderate levels of pain catastrophizing .
as these are known to be poor prognostic indicators for treatment success , it is essential that clinicians take a broad biopsychosocial approach to the treatment of this condition , and communicate this to patients , in order to engage them in effective management of their pain .
therefore our cppc takes a holistic approach , in which assessments of all new referrals include evaluations by a pain specialist , a physiotherapist trained in women s health , and a clinical psychologist .
a social worker is also available to provide assistance with psychosocial needs . at a subsequent team meeting
we formulate joint treatment plans that take into account women s physical , psychological , and medical needs .
the importance of taking a multi - disciplinary approach to cpp was also highlighted in other recent studies.11,21 these authors found that functional impairment and pain interference were more strongly related to psychiatric symptoms , such as anxiety and depression , than to pain severity .
our findings would support that contention , and their proposal that pain management must include the identification of psychological variables that can influence pain outcomes . in the case of pelvic pain
this needs to include sexual and relationship history.17 only when these are taken into account , along with relevant medical and physical histories and symptoms , will patients receive the care that this challenging condition demands . | ### Summary:
: objectivechronic pelvic pain ( cpp ) is widely acknowledged as a common problem with significant consequences for those diagnosed with this condition .
there is a lack of studies with good sample size that provide a comprehensive psychological profile of women presenting to specialist chronic pain clinics .
therefore , the objective of this study was to describe the psychological profile of a representative sample of women presenting with cpp at a tertiary referral center.designthis was a cross - sectional study .
women were asked to complete a questionnaire assessing symptoms of anxiety and depression , pain severity and interference , pain self - efficacy and catastrophizing beliefs , and sexual functioning.methodsone-hundred and seventy - five women with cpp were recruited when they attended their initial assessment at a specialist cpp clinic of the royal women s hospital , a public hospital in melbourne , australia.resultsover 75% of the participants had experienced pain for longer than 2 years .
fifty - three percent of women experienced either moderate or severe anxiety , and 26.7% experienced moderate - to - severe depression .
there were strong correlations between depressive symptoms and pain interference , pain catastrophizing and self - efficacy beliefs.conclusionour findings confirm previous evidence for high levels of psychological distress and functional impairment associated with this condition , and extend these findings by including measures that are highly relevant to treatment planning , such as thinking styles and pain self - efficacy .
therefore , treatment of this complex condition needs to be holistic , and a multidisciplinary approach is likely to be the best way to achieve this . |
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: microbial keratitis ( mk ) is an ocular emergency that requires prompt and specific management to maximise visual outcome and preserve ocular integrity .
although there is variability in the reported rates , it appears that the rate of this potentially devastating disease has risen in the last 5060 years [ 2 , 3 ] .
this increase in incidence has been attributed to specific risk factors such as the use of contact lens [ 3 , 4 ] .
bacterial keratitis ( bk ) is the most common form of mk . to date , 77 species from 42 genera of bacteria have been identified to have a potential to cause keratitis .
the treatment regimen of bk has long been debated with one school of thought endorsing corneal scraping and combination antibiotic therapy and the other empirical fluoroquinolone therapy alone [ 6 , 7 ] .
guidelines have been published for the treatment of the disease , with equal priority assigned to the laboratory results and the clinical impression , severity of the condition , and the pathogen [ 8 , 9 ] .
the treatment protocol based on clinical diagnosis alone has the benefit of allowing rapid intervention but does not provide confirmation of the causative organism which can otherwise be hard to identify due to overlapping clinical signs from different pathogens .
furthermore , confounding factors such as inappropriate treatment ( e.g. , corticosteroids ) can lead to severe complications .
treatment based on laboratory culture has the advantage that a positive culture together with antibiotic sensitivities allows the selection of the appropriate class of antibiotics , thus avoiding unnecessary use of ineffective and potentially toxic drugs [ 6 , 11 ] .
moreover if a corneal scrape is performed , it can facilitate healing through superior antibiotic penetration and debridement of necrotic tissues .
the downside , however , is that there is a delay in culturing bacteria and refining sensitivities , and therefore , commonly a dual approach is taken whereby empirical therapy is commenced following corneal scraping and treatment is refined as necessary according to clinical response and laboratory - based sensitivity data .
in the present study , the ocular microbiological data for all mk cases admitted to greenlane clinical centre ( gcc ) , auckland , new zealand ( nz ) , over the 2-year period , 2013 to 2014 , were reviewed , to determine the bacterial species causing keratitis and their susceptibility to antibiotics in laboratory testing .
findings were further compared to those reported in the literature in 2003 , which relate to the same catchment area over the period 19992001 , to help identify local aetiological trends , confirm sensitivity patterns to commonly prescribed antibiotics , and inform protocols for optimal management of the disease .
an institutional review board - approved ( uahpec 013549 ) , retrospective review of culture - proven bk was undertaken for the period 1 january 2013 to 30 december 2014 at gcc .
patients hospitalized for intensive antibiotic treatment were identified through a computerized diagnostic code search and ward discharge record search ( with keratitis listed as a discharge diagnosis ) .
a single author ( s. marasini ) reviewed the medical records to extract relevant information concerning the growth and susceptibility of pathogens .
the microbiological laboratory records were reviewed for gram stain , culture isolates , and antibiotic sensitivity results .
while gram stain results were usually available the same day , various media were routinely incubated for a total of 10 days to 2 weeks depending on the media before giving a final report .
possible bacterial contaminants ( as indicated in the laboratory report ) were excluded from analysis .
depending on the current laboratory protocols and the isolated organism , the following antimicrobial agents were included in susceptibility testing : penicillin ( amoxicillin , amoxi / clavulanate , ticarcillin / clavulanate , penicillin , and flucloxacillin ) , fluoroquinolone ( ciprofloxacin ) , cephalosporins ( cefazolin , cefuroxime , and ceftazidime ) , aminoglycoside ( tobramycin , gentamicin , and neomycin ) , chloramphenicol , and tetracycline . in vitro susceptibility was determined by the kirby - bauer disk diffusion method and minimum inhibitory concentration ( mic ) .
isolates of intermediate sensitivity were categorized as susceptible organisms because the concentration of drug achieved at the ocular surface is much greater than that used for in vitro susceptibility testing .
statistical analysis was performed using graphpad prism 6 software , using the fisher exact test and statistical significance was set at p 0.05 .
there were 196 cases ( 194 patients ) of severe microbial keratitis between january 2013 and december 2014 . in 154 cases ,
conjunctival swab culture was available in 11 cases and both corneal scrape and swab cultures were available for 126 cases .
the remainder of the cases received treatment or were continued on treatment , without culture .
at least one risk factor was identified in 80.6% cases and included contact lens wear ( 33.1% ) , ocular surface disease of varying etiology ( 29.6% ) , previous ocular surgery ( 18.6% ) , trauma ( 14.8% ) , and steroid use ( 8.2% ) .
multiple risk factors were identified in 13.8% of cases and a cause could not be identified in 19.4% .
twenty - six patients were diabetic with ( n = 16 ) or without ( n = 10 ) known ocular risk factors . among the culture positive cases in the contact lens group ( n = 25 ) , 72% grew gram - negative organisms , which included pseudomonas aeruginosa ( n = 14 ) and serratia species ( n = 5 ) .
more than two organisms grew in 10 instances of contact lens wearers ; three organisms grew in two and five organisms in one instance . in the cases in which moraxella species grew ( n = 16 ) , risk factors identified were ocular surface disease ( n = 5 ) , prior ocular surgery ( n = 3 ) , and ocular trauma ( n = 2 ) .
the species of fungi and yeast included fusarium solani ( 2 ) , candida albicans ( 1 ) , aspergillus fumigatus ( 1 ) , candida guilliermondii ( 1 ) , candida parapsilosis complex ( 2 ) , and epicoccum species ( 1 ) .
in addition , herpes simplex virus ( hsv ) was isolated in 16 cases and herpes zoster virus ( hzv ) in two .
on rescrape , no growth was identified in seven but the remainder grew organisms such as corynebacterium species ( 2 ) , staphylococcus species ( 2 ) , streptococcus species ( 3 ) , and moraxella species ( 2 ) .
of all the scrapes , 89 ( 57.8% ) yielded bacterial cultures growing 126 organisms : 73 ( 58% ) gram - positive and 53 ( 42% ) gram - negative .
twenty - nine cases grew more than one organism : two ( n = 20 ) , three ( n = 5 ) , four ( n = 3 ) , and more than four organisms ( n = 1 ) .
conjunctival swab staining was performed in 137 samples with gram stain positive in 55 ( 40.1% ) : 28 ( 50.9% ) gram - positive and 27 ( 49.1% ) gram - negative .
swab culture and corneal scrape culture grew different organisms . in a number of cases ,
contact lenses were cultured ( n = 16 ) , contact lens cases were cultured ( n = 7 ) , or both were cultured ( n = 5 ) .
contact lens culture grew gram - negative organisms in eight cases ( pseudomonas aeruginosa in five of these cases ) and contact lens case culture grew pseudomonas aeruginosa in one case .
one contact lens culture did not grow any organism , and one grew an organism absent on corneal scrape .
thirty - five different bacterial species from 18 genera were isolated over the two - year period .
staphylococcus species were the most commonly isolated organisms ( 38.2% ) , followed by pseudomonas species ( 21.3% ) , streptococcus species ( 20.2% ) , moraxella species ( 18% ) , and corynebacterium species ( 16.9% ) .
table 2 shows the in vitro susceptibility of gram - positive and gram - negative bacteria to a range of antibiotics tested during the study period . for gram - negative bacteria ,
100% of isolates were susceptible to tested aminoglycosides ( gentamicin , neomycin , and tobramycin ) . among the cephalosporins ,
67% of gram - negative isolates were resistant to cefuroxime but 100% were susceptible to cefazolin and ceftazidime .
all gram - positive bacteria were susceptible to aminoglycosides , cephalosporins , vancomycin , chloramphenicol , erythromycin , flucloxacillin , and tetracycline . some of the gram - positive isolates exhibited resistance to ciprofloxacin ( 1.2% ) and penicillin ( 49% ) .
based on the susceptibility test , the relative effectiveness of commonly used empirical antibiotics , including ciprofloxacin and a combination regimen , cefazolin with gentamicin or tobramycin for gram - negative bacteria ( pseudomonas aeruginosa and non - pseudomonas ) was analysed .
all the isolates were equally susceptible ( 100% ) to ciprofloxacin and combination regimen of cefazolin and gentamicin ( or tobramycin ) .
the aim of the present study was to identify the current spectrum of bacteria causing keratitis leading to hospitalization in a tertiary care centre with a wide catchment area in auckland , new zealand , and to evaluate recent antibiotic susceptibility patterns .
sixty - seven percent of isolates were resistant to cefuroxime , which forms the most common empirical dual therapy prescription along with tobramycin in our centre ( unpublished data ) .
aminoglycosides ( gentamicin , neomycin , and tobramycin ) demonstrated high in vitro efficacy along with cefazolin , erythromycin , vancomycin , tetracycline , and doxycycline each at 100% compared to ciprofloxacin and chloramphenicol at rates of 98.8% and 94.7% , respectively .
bk requires treatment as an ocular emergency with the application of an effective antibiotic delivered at a sufficient dose , especially when large ulcers involve the visual axis .
the initial recommended treatment regimen in bk is either a fortified preparation of a cephalosporin ( 5% ) with a fortified aminoglycoside ( 1.5% tobramycin or gentamicin ) or fluoroquinolone monotherapy , until the corneal surface has been sterilized [ 6 , 9 ] .
however , this therapy is toxic in prolonged use , and sterility does not equate directly with healing or resolution of inflammation , reflected by healing and closure of the corneal epithelium . in the last decade , initial empirical treatment in auckland hospital ( nz ) has shifted from the first - generation fortified cephalosporin ( cefazolin ) together with the fortified aminoglycoside ( gentamicin or tobramycin ) towards a second - generation cephalosporin ( cefuroxime ) combined with an aminoglycoside ( tobramycin ) .
cefazolin and ceftazidime were very effective ( 100% ) against tested gram - positive and gram - negative bacteria .
indeed , for ceftazidime there has been no report of an increase in resistance since 1994 , and it was highly effective ( 100% ) against pseudomonas aeruginosa in the current study . although dual therapy is commonly prescribed ( 64% ) in auckland , the in vitro sensitivity of cefuroxime was tested only in nine cases in which two - thirds showed resistance , differing from the findings ( 5% resistance ) in waikato ( nz ) . very high in vitro resistance to cefuroxime ( 49.1% ) has been recently reported ( 2011 ) from oxford , uk , for the bk isolates for the decade 19992009 , particularly within gram - negative organisms ( 91.2% ) ( table 4 ) .
aminoglycosides such as gentamicin are commonly used to increase the antimicrobial efficacy in dual therapy , especially against species ofstreptococci . in the present study ,
bk isolates were highly susceptible to gentamicin , a finding consistent with reports from elsewhere .
we observed that the in vitro efficacy of dual therapy consisting of cefazolin and gentamicin ( or tobramycin ) was equally effective ( 100% ) to ciprofloxacin monotherapy against pseudomonas aeruginosa and other non - pseudomonas gram - negative bacteria .
neomycin exhibited 45.4% intermediate resistance to pseudomonas isolates , however , based on our methodology ; we have classified them as sensitive organisms .
the type and frequency of organisms causing bk in this study vary from other centres .
infections due to fungi and yeasts ( 8 cases ) and acanthamoeba ( a single case ) were uncommon , consistent with previous literature .
we found a higher rate of streptococcus species compared to that reported from the same catchment area in auckland in 2003 and from other new zealand catchments such as wellington and waikato .
the rate of isolation of staphylococcus species was less than other centres but that of moraxella and corynebacterium species was comparable within centres in nz ( table 5 ) . interestingly , polymicrobial infection is common in auckland ( 32.5% ) , similar to the previous report ( 33.3% ) but approximately four times higher than that in waikato ( 8.3% ) .
the climate and latitude variations perhaps play a role in the type and frequency difference in organisms ' isolation and the regional variations have been well documented previously .
we observed a higher isolation rate of pseudomonas during the study period than other nz cities [ 15 , 16 ] and than the previous report from the same hospital ( p = 0.05 ) as well as in australia ( 8.3% ) , but much lower than that in taiwan ( 46.7% ) .
the rates of pseudomonas isolation are observed to differ between locations such as in los angeles ( 57% and 43% at two locations ) , germany ( 10% ) , brisbane ( 17% ) , and china ( 20% ) .
factors found to be influencing pseudomonas infections have been explored in several studies and one of the commonest risk factors is determined to be contact lens use . in our study sample and
consistent with previous studies , contact lens use was the most common risk factor ( 33.1% ) followed by ocular surface disease of varying etiology ( 29.6% ) . in contact
lens wearers , infections due to gram - negative bacteria prevailed ( 72% ) , of which 78% arose from pseudomonas aeruginosa alone . another notable observation was the reduced incidence of methicillin - resistant staphylococcus aureus ( mrsa ) ( one isolate ) , an organism which is most commonly isolated following ocular surgery , being more common in us provinces and resistant to fourth - generation fluoroquinolone . interestingly , over the last decade , there was a significant decrease in the infections caused by coagulase - negative staphylococcus aureus ( table 1 ) . in the present study ,
a positive culture rate on presentation was found to be 57.8% , which is less compared to that from other nz cities that range from 58% to 85% [ 1517 ] , but similar to that from the uk ( 53.7% ) .
prior use of antibiotics or failure to cease antibiotic use prior to corneal scraping may result in a negative culture .
auckland hospital is a tertiary referral centre ; therefore , the prior use of topical antimicrobial therapy , especially in contact lens wearers , likely contributed to the observed variance at this centre .
in fact , corneal scrapes from 40 contact lens wearers failed to grow any organism in this study .
moreover , topical anaesthetic agents applied before corneal scraping may also produce false negative results . in 16 cases ,
the contact lens was cultured , including one case , which grew an organism that did not grow on the corneal scrape .
this might suggest that invasive corneal rescraping might not be necessary if contact lenses / lens cases are cultured more frequently at presentation . in the current study ,
conjunctival swab staining was positive in 40% of the samples tested and 23 ( of 126 ) organisms grew in swab culture .
the gram stain of a conjunctival swab is not as sensitive as that of a corneal scrape or culture but does give an early indication regarding first - line treatment .
however , many community ophthalmologists overlook the potential benefit of these quick , less invasive , and relatively inexpensive techniques and begin an empiric approach to therapy , with the assumption that , regardless of the identity of the organism , broad spectrum antibiotic treatment has a high probability of success .
however , as a downside , this empiric practice has been suggested to be a factor contributing to antibiotic resistance .
the emergence of resistance to antimicrobial agents is a global public health concern and resistance patterns vary greatly with geographical location .
periodic susceptibility testing ensures that the antimicrobials being used still have good coverage against isolates of bk .
these findings are similar to other studies , which report susceptibilities that range from 72% to 100% [ 12 , 14 , 15 , 28 , 29 ] .
however , in brazil , gentamicin and tobramycin have demonstrated decreased efficacy , from 95% to less than 80% , over a period of 15 years since 1985 . a similar trend has also been reported in taiwan .
since the same class of antibiotics may exhibit different efficacies against bk isolates from different regions , the choice of an antibiotic should be based on a prudent analysis of the location as well as risk factors and the historical data .
universally , fluoroquinolones are widely used as monotherapy , reportedly constituting 95% of all prescriptions for bk ( 80% of which were ciprofloxacin ) in australia during 20012003 ( not limited to bk requiring hospital admission ) . because of their broad spectrum that ranges from 72% to 99% [ 1315 , 2830 ] and interest in emerging resistance patterns ( mainly against gram - positive cocci , ranging from 6% to 35% ) [ 20 , 3133 ] ,
they exhibit equivalent efficacy when compared with the standard dual fortified antibiotic regime in terms of corneal healing and comfort factors , offering an effective alternative , particularly when compliance is the main concern .
however , 30.7% of corneal isolates in india have been reported to show resistance to ciprofloxacin , with a similar picture in south florida ( 11% in 1990 to 28% in 1998 ) and pittsburgh ( from 5.8% in 1993 to 35.0% in 1997 ) . in the present study
, ciprofloxacin demonstrated 100% efficacy against gram - negative bacteria , an observation similar to that from waikato ( 99% ) and christchurch ( 100% ) in new zealand .
however , one - gram - positive pathogen ( nocardia veteran ) showed resistance against ciprofloxacin . in christchurch ,
12% of gram - positive bacteria were resistant to ciprofloxacin , which differs from the present study ( 1.2% ) .
the observed trend of bk isolates developing resistance against ciprofloxacin in different study centres suggests that an alternative to ciprofloxacin should perhaps be considered .
as ofloxacin has recognised associations with ocular perforation , alternative newer generation fluoroquinolones with demonstrated activity in vitro and in vivo against gram - positive cocci need to be considered .
2003 ) showed a greater in vitro efficacy of fourth - generation fluoroquinolones to staphylococcus aureus resistant to ciprofloxacin , ofloxacin , and levofloxacin .
2008 ) reported resistance to the newer generation fluoroquinolone and levofloxacin , at a rate of 15.5% .
the increasing resistance of antibiotics ( mainly fluoroquinolones ) against bk isolates , especially in indian subcontinents , is attributable to the widespread use of antibiotics for systemic infections and prophylaxis and the availablility of over - the - counter antibiotics . in new zealand , a survey ( 2003 ) was conducted to identify the prescribing trends in infectious keratitis and it was found that fluoroquinolone monotherapy was widely used to treat milder cases of keratitis .
our results indicate that ciprofloxacin continues to be effective in vitro against 98.8% bk isolates and this has changed minimally over the last decade , according to reports from different cities in the country [ 15 , 16 ] .
( 2002 ) showed that the fourth - generation fluoroquinolones were more potent against gram - positive bacteria and were equally effective against gram - negative bacteria compared to second- and third - generation fluoroquinolones .
harmonizing this evidence with other observations , fourth - generation fluoroquinolone ( gatifloxacin and moxifloxacin ) can perhaps be considered as an alternative to ciprofloxacin to treat bk at the present time , where resistance issues exist . among other antibiotics
tested , vancomycin was found to be 100% effective against gram - positive bacteria . in the literature ,
chloramphenicol was deemed 100% effective against tested gram - positive bacteria and showed 94.7% efficacy against gram - negative bacteria , consistent with other nz studies [ 15 , 17 ] . in the uk , over the last decade ,
32% bk isolates developed resistance against chloramphenicol , which is high compared to the reports from nz cities , where the reported resistance is between 3.2% and 6.9% ( table 4 ) [ 12 , 1517 ] .
it must be noted that many organisms could not be included in the study because of failure to grow in the microbiology laboratory , possibly introducing some selection bias and possibly confounding the in vitro susceptibility results to a degree .
newer generation fluoroquinolones are found to be effective against bk isolates , but only ciprofloxacin was tested in vitro .
although it is found to be highly effective , a guarded use is advised in a context of global variation in efficacy against bk isolates .
also the possibility that gram - positive rods such as propionibacterium species and gram - positive cocci such as coagulase - negative staphylococcus species may represent nonpathogenic commensal species from the ocular surface can not be excluded . notwithstanding with these limitations ,
firstly , the relative proportion of pseudomonas infections is higher in auckland compared to other nz cities and compared to prior records from the same city .
secondly , the antibiotic sensitivity pattern has not changed significantly in new zealand over the last decade .
the in vitro efficacy of aminoglycosides , cefazolin , ceftazidime , vancomycin , and tetracycline remains high but bk isolates are observed to be developing resistance against cefuroxime .
finally , ciprofloxacin has demonstrated equivalent efficacy against bk isolates in vitro compared with dual therapy consisting of cefazolin and gentamicin ( or tobramycin ) combination . | ### Summary:
: background . the bacteria isolated from severe cases of keratitis and their antibiotic sensitivity
are recognised to vary geographically and over time . objectives . to identify the most commonly isolated bacteria in keratitis cases admitted over a 24-month period to a public hospital in auckland , new zealand , and to investigate in vitro sensitivity to antibiotics . methods .
hospital admissions for culture - proven bacterial keratitis between january 2013 and december 2014 were identified .
laboratory records of 89 culture positive cases were retrospectively reviewed and antibiotic sensitivity patterns compared with previous studies from other nz centres . results . from 126 positive cultures , 35 species were identified .
staphylococcus was identified to be the most common isolate ( 38.2% ) , followed by pseudomonas ( 21.3% ) . over the last decade ,
infection due to pseudomonas species , in the same setting , has increased ( p 0.05 ) .
aminoglycosides , cefazolin , ceftazidime , erythromycin , tetracycline , and doxycycline were 100% effective against tested isolates in vitro .
amoxicillin ( 41.6% ) , cefuroxime ( 33.3% ) , and chloramphenicol ( 94.7% ) showed reduced efficacy against gram - negative bacteria , whereas penicillin ( 51% ) and ciprofloxacin ( 98.8% ) showed reduced efficacy against gram - positive bacteria . conclusions . despite a shift in the spectrum of bacterial keratitis
isolates , antibiotic sensitivity patterns have generally remained stable and show comparability to results within the last decade from nz centres . |
<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:
: there is a large gap between our ability to collect data and our ability to interpret it .
the challenge faced by today 's researchers is to develop effective ways to analyze the vast amount of data that has been and will continue to be collected . first released in 2001 , onto - tools
this is achieved by using a probabilistic functional analysis that bridges the gap between low - level , high - throughput gene expression data and high - level functional knowledge .
this analysis approach has become de facto standard in the second - stage analysis of microarray experiments ( 618 ) .
the onto - tools suite includes : ( i ) onto - express , which can be used to translate lists of differentially regulated genes into a better understanding of the underlying biological phenomena through the use of gene ontology ( go ) ; ( ii ) onto - design , which can be used to select the best set of genes to be included on a custom microarray designed for the study of a given biological phenomenon ; ( iii ) onto - compare , which can be used to analyze the functional bias of various focused commercial microarrays and select the one that is most appropriate for a given biological hypothesis ; ( iv ) onto - translate , which can be used to translate lists of genes from one reference system to another ( e.g. from genbank accession numbers to unigene cluster ids to affymetrix probe ids , etc . ) ; ( v ) onto - miner , which provides a unified access point and an application programming interface allowing queries for various information , such as the gene name , official symbol , reference accession number , coded protein , etc . ; and ( vi ) pathway - express , which helps the users find most interesting pathway(s ) involving their genes of interest .
previous publications have described in detail the motivation , implementation and validation of these tools ( 15 ) .
this paper describes a new tool added to the ensemble and discusses various other additions and enhancements made to the existing tools and the database .
in february 2005 , ncbi phased out its locuslink database and replaced it with the entrez gene database ( 19 ) .
all data previously stored in locuslink ( 20 ) have been migrated to the new gene database .
however , the structure of the new database and the format of the files used to export this data have changed .
previously , the onto - tools database used the locuslink gene as its backbone data structure to link the functional annotations imported from go ( 21,22 ) with the sequence data imported from dbest and unigene .
hence , the locuslink phase - out has had a dramatic impact on the schema of the onto - tools back - end annotation database , as well as on the tools themselves .
the onto - tools back - end database has been re - designed to use a new data structure based on the gene data model .
in addition , the database download and parser modules are also modified to download and parse the entrez gene database . over the past year , onto - tools ( ot ) database has been expanded dramatically .
now , the database contains various types of data from 13 new databases which include : swiss - prot ( 23 ) , trembl ( 24 ) , pir ( 25 ) , uniprot ( 26 ) , eukaryotic promoter database ( epd ) ( 27 ) , human genome nomenclature committee ( hgnc ) ( 28 ) , genpept , online mendelian inheritance in man ( omim ) ( 28 ) , protein data bank ( pdb ) ( 29 ) , iproclass ( 24 ) , homologene ( ) , refseq ( 20 ) and go ( 21,22 ) .
the other databases previously integrated in the onto - tools database include dbest ( 30 ) , genbank ( 31 ) , unigene ( 32 ) , kegg ( 33 ) , wormbase ( ) , netaffx , dbest library ( ) and evoc ( 34 ) . over the past year
, we have added support for the functional profiling of 19 new organisms by integrating annotations from go database . onto - express ( oe )
now supports functional profiling for a total of 24 organisms , including homo sapiens , saccharomyces cerevisiae , drosophila melanogaster , mus musculus , arabidopsis thaliana , caenorhabditis elegans , rattus norvegicus , oryza sativa , danio rerio , dictyostelium discoideum , candida albicans , bacillus anthracis ames , coxiella burnetii rsa 493 , geobacter sulfurreducens pca , listeria monocytogenes 4b f2365 , methylococcus capsulatus bath , pseudomonas syringae dc3000 , shewanella oneidensis mr-1 , vibrio cholerae , leishmania major , plasmodium falciparum , schizosaccharomyces pombe , trypanosoma brucei and glossina morsitans .
in addition to broadening its scope by adding new organisms , oe is now able to support 11 more types of input data .
previously , oe allowed the users to submit a list of genbank accession numbers , unigene cluster ids , affymetrix probe ids , locuslink ids , wormbase accession ids and gene symbols .
now oe allows the users to submit any of the database ids used in the go annotations .
these i d types include saccharomyces genome database ( sgd ) ids , flybase ids , mouse genome informatics ( mgi ) ids , the arabidopsis information resource ( tair ) ids , the institute for genomic research ( tigr ) ids , rat genome database ( rgd ) ids , gramene ids , zebrafish information network ( zfin ) ids , dictybase ids , candida genome database ( cgd ) ids and sanger genedb ids . in order to correctly interpret the results of any experiment , the researchers need to build a complete picture of the biological phenomenon under study , to the extent possible
. most often , one needs to take into account various types of data : dna sequence , mrna sequence and expression , protein expression and structure , gene interactions , protein protein interactions , etc .
however , various databases are rather specialized ( e.g. genbank focuses on sequence data , pdb focuses on protein structure data , swiss - prot focuses on protein annotations , etc . ) and no public or private resource contains all available data . in order to allow the users to navigate from one resource to another , as often required , all public databases cross - reference to some of the other databases .
for example , an mrna or expressed sequence tag ( est ) database ( e.g. unigene ) will provide links to a gene database ( e.g. entrez gene ) , indicating the gene from which the mrna is transcribed and to a protein database ( e.g. genpept ) that will provide information about the protein which is translated from the mrna .
such a gene database will also be cross - linked to a genome map database ( e.g. ncbi genome assembly ) to help with the location of the gene on its genome .
similarly , a protein database ( e.g. swiss - prot ) will provide links to a gene database ( e.g. entrez gene ) and a protein structure database ( e.g. pfam or interpro ) .
more recently , this cross - linking has started to be extended to include clinical aspects .
for example , disease databases , such as omim , can provide a link to a gene database ( e.g. entrez gene ) where one can obtain functional annotations for those genes involved in specific diseases . in a parallel movement , organism - specific databases , such as mgi , rgd , etc .
these organism - specific databases also provide links to other large - scale , organism - independent , generic databases , such as entrez gene , swiss - prot , etc . the major problem in the field is that each of these databases has its own schema , which is designed independently of any other .
in consequence , each of these resources will use its own main identifier ( i.e. will have independent name - spaces ) .
for example , genbank uses accession numbers , unigene uses cluster ids , entrez gene uses gene symbols and gene ids , swiss - prot uses swiss - prot accession ids , trembl uses trembl ids , etc .
for example , the gene beta actin in mouse is referred to as mgi:87904 in mgi , actb ( gene i d : 11461 ) in entrez gene , mm.297 in unigene , actb_mouse ( primary accession number : p60710 ) in uniprot and tc1242885 in tigr gene index .
in addition , the beta actin gene in mouse is referred to by 29 mrna sequences and 4552 ests in dbest , 5 secondary accession numbers in uniprot , 4 other accession ids in mgi and 5 probe ids on 4 different affymetrix mouse arrays .
the burden of mapping various types of i d on each other is left entirely on the shoulders of the researchers , who often have to revert to cutting and pasting lists of ids from one database to another . as a side effect of the efforts to link genomics , proteomics and annotation databases , some information is replicated in multiple databases . an immediate problem created by this duplication is data coherency and consistency . the same record stored in different databases will be updated at different times , which means that different versions will co - exists for a while .
for example , one can obtain functional annotations for a gene from either the go database or entrez gene database .
note that the annotations in entrez gene and go database are obtained from the same source , the go annotation project at ebi .
an illustrative example is the gene erythrocyte membrane protein band 4.1-like 3 [ h.sapiens ] ( entrez gene id:23136 , epb41l3 ) .
a search for this gene in the go annotation database returned only one go term , plasma membrane .
however , the same gene , epb41l3 , is annotated with 6 go terms : actin binding , structural molecule activity , cortical actin cytoskeleton organization and biogenesis , cytoplasm , cytoskeleton and plasma membrane in the entrez gene database . onto - translate ( ot )
is designed to address these name - space issues and help the user with the problem of mapping various types of ids on each other .
the ultimate goal of ot is to provide the users with a non - redundant and complete mapping from any type of identification system to any other type .
uses the custom design of onto - tools database that integrates 19 sequence , gene , protein and annotation databases .
the automated functional profiling approach of oe helps the researchers to better understand the biological phenomenon under study by pointing out statistically significant cellular functions .
however , graphical representations of gene interactions ( pathways ) have been shown to be very useful ( 33,35,36 ) . as more data become available , the question is there a known pathway containing my gene(s ) of interest? will gradually transform into how do i find the most interesting pathway(s ) involving my gene(s)? pathway - express ( pe ) is a new tool in the onto - tools ensemble that was designed to answer such questions .
when the user submits a list of genes , the system performs a search and builds a list of all associated pathways .
after generating a list of pathways for the input list of genes from the onto - tools database , pe first calculates a perturbation factor pf(g ) for each input gene .
this perturbation factor takes into account the ( i ) normalized fold change of the gene and ( ii ) the number and amount of perturbation of genes downstream from it .
the impact factor of the entire pathway includes a probabilistic term that takes into consideration the proportion of differentially regulated genes on the pathway and gene perturbation factors of all genes in the pathway .
the impact factors of all pathways are used to rank the pathways before presenting them to the user .
in figure 1 , for example , the pathway selected as the most important had only three differentially regulated genes out of 209 genes
. however , this pathway is dramatically impacted if the two transmembrane receptors and the ligand shown are affected .
in february 2005 , ncbi phased out its locuslink database and replaced it with the entrez gene database ( 19 ) .
all data previously stored in locuslink ( 20 ) have been migrated to the new gene database .
however , the structure of the new database and the format of the files used to export this data have changed .
previously , the onto - tools database used the locuslink gene as its backbone data structure to link the functional annotations imported from go ( 21,22 ) with the sequence data imported from dbest and unigene .
hence , the locuslink phase - out has had a dramatic impact on the schema of the onto - tools back - end annotation database , as well as on the tools themselves .
the onto - tools back - end database has been re - designed to use a new data structure based on the gene data model .
in addition , the database download and parser modules are also modified to download and parse the entrez gene database . over the past year , onto - tools ( ot ) database has been expanded dramatically .
now , the database contains various types of data from 13 new databases which include : swiss - prot ( 23 ) , trembl ( 24 ) , pir ( 25 ) , uniprot ( 26 ) , eukaryotic promoter database ( epd ) ( 27 ) , human genome nomenclature committee ( hgnc ) ( 28 ) , genpept , online mendelian inheritance in man ( omim ) ( 28 ) , protein data bank ( pdb ) ( 29 ) , iproclass ( 24 ) , homologene ( ) , refseq ( 20 ) and go ( 21,22 ) .
the other databases previously integrated in the onto - tools database include dbest ( 30 ) , genbank ( 31 ) , unigene ( 32 ) , kegg ( 33 ) , wormbase ( ) , netaffx , dbest library ( ) and evoc ( 34 ) .
over the past year , we have added support for the functional profiling of 19 new organisms by integrating annotations from go database . onto - express ( oe )
now supports functional profiling for a total of 24 organisms , including homo sapiens , saccharomyces cerevisiae , drosophila melanogaster , mus musculus , arabidopsis thaliana , caenorhabditis elegans , rattus norvegicus , oryza sativa , danio rerio , dictyostelium discoideum , candida albicans , bacillus anthracis ames , coxiella burnetii rsa 493 , geobacter sulfurreducens pca , listeria monocytogenes 4b f2365 , methylococcus capsulatus bath , pseudomonas syringae dc3000 , shewanella oneidensis mr-1 , vibrio cholerae , leishmania major , plasmodium falciparum , schizosaccharomyces pombe , trypanosoma brucei and glossina morsitans .
in addition to broadening its scope by adding new organisms , oe is now able to support 11 more types of input data .
previously , oe allowed the users to submit a list of genbank accession numbers , unigene cluster ids , affymetrix probe ids , locuslink ids , wormbase accession ids and gene symbols .
now oe allows the users to submit any of the database ids used in the go annotations .
these i d types include saccharomyces genome database ( sgd ) ids , flybase ids , mouse genome informatics ( mgi ) ids , the arabidopsis information resource ( tair ) ids , the institute for genomic research ( tigr ) ids , rat genome database ( rgd ) ids , gramene ids , zebrafish information network ( zfin ) ids , dictybase ids , candida genome database ( cgd ) ids and sanger genedb ids .
in order to correctly interpret the results of any experiment , the researchers need to build a complete picture of the biological phenomenon under study , to the extent possible . most often , one needs to take into account various types of data : dna sequence , mrna sequence and expression , protein expression and structure , gene interactions , protein protein interactions , etc .
however , various databases are rather specialized ( e.g. genbank focuses on sequence data , pdb focuses on protein structure data , swiss - prot focuses on protein annotations , etc . ) and no public or private resource contains all available data . in order to allow the users to navigate from one resource to another , as often required , all public databases cross - reference to some of the other databases .
for example , an mrna or expressed sequence tag ( est ) database ( e.g. unigene ) will provide links to a gene database ( e.g. entrez gene ) , indicating the gene from which the mrna is transcribed and to a protein database ( e.g. genpept ) that will provide information about the protein which is translated from the mrna .
such a gene database will also be cross - linked to a genome map database ( e.g. ncbi genome assembly ) to help with the location of the gene on its genome .
similarly , a protein database ( e.g. swiss - prot ) will provide links to a gene database ( e.g. entrez gene ) and a protein structure database ( e.g. pfam or interpro ) .
more recently , this cross - linking has started to be extended to include clinical aspects .
for example , disease databases , such as omim , can provide a link to a gene database ( e.g. entrez gene ) where one can obtain functional annotations for those genes involved in specific diseases . in a parallel movement , organism - specific databases , such as mgi , rgd , etc .
these organism - specific databases also provide links to other large - scale , organism - independent , generic databases , such as entrez gene , swiss - prot , etc .
the major problem in the field is that each of these databases has its own schema , which is designed independently of any other . in consequence ,
each of these resources will use its own main identifier ( i.e. will have independent name - spaces ) .
for example , genbank uses accession numbers , unigene uses cluster ids , entrez gene uses gene symbols and gene ids , swiss - prot uses swiss - prot accession ids , trembl uses trembl ids , etc .
for example , the gene beta actin in mouse is referred to as mgi:87904 in mgi , actb ( gene i d : 11461 ) in entrez gene , mm.297 in unigene , actb_mouse ( primary accession number : p60710 ) in uniprot and tc1242885 in tigr gene index .
in addition , the beta actin gene in mouse is referred to by 29 mrna sequences and 4552 ests in dbest , 5 secondary accession numbers in uniprot , 4 other accession ids in mgi and 5 probe ids on 4 different affymetrix mouse arrays .
the burden of mapping various types of i d on each other is left entirely on the shoulders of the researchers , who often have to revert to cutting and pasting lists of ids from one database to another . as a side effect of the efforts to link genomics , proteomics and annotation databases , some information is replicated in multiple databases . an immediate problem created by this duplication is data coherency and consistency . the same record stored in different databases will be updated at different times , which means that different versions will co - exists for a while . for example , one can obtain functional annotations for a gene from either the go database or entrez gene database .
note that the annotations in entrez gene and go database are obtained from the same source , the go annotation project at ebi .
an illustrative example is the gene erythrocyte membrane protein band 4.1-like 3 [ h.sapiens ] ( entrez gene id:23136 , epb41l3 ) .
a search for this gene in the go annotation database returned only one go term , plasma membrane .
however , the same gene , epb41l3 , is annotated with 6 go terms : actin binding , structural molecule activity , cortical actin cytoskeleton organization and biogenesis , cytoplasm , cytoskeleton and plasma membrane in the entrez gene database . onto - translate ( ot )
is designed to address these name - space issues and help the user with the problem of mapping various types of ids on each other .
the ultimate goal of ot is to provide the users with a non - redundant and complete mapping from any type of identification system to any other type .
uses the custom design of onto - tools database that integrates 19 sequence , gene , protein and annotation databases .
the automated functional profiling approach of oe helps the researchers to better understand the biological phenomenon under study by pointing out statistically significant cellular functions .
however , graphical representations of gene interactions ( pathways ) have been shown to be very useful ( 33,35,36 ) . as more data become available , the question is there a known pathway containing my gene(s ) of interest? will gradually transform into how do i find the most interesting pathway(s ) involving my gene(s)? pathway - express ( pe ) is a new tool in the onto - tools ensemble that was designed to answer such questions .
when the user submits a list of genes , the system performs a search and builds a list of all associated pathways .
after generating a list of pathways for the input list of genes from the onto - tools database , pe first calculates a perturbation factor pf(g ) for each input gene .
this perturbation factor takes into account the ( i ) normalized fold change of the gene and ( ii ) the number and amount of perturbation of genes downstream from it .
the impact factor of the entire pathway includes a probabilistic term that takes into consideration the proportion of differentially regulated genes on the pathway and gene perturbation factors of all genes in the pathway .
the impact factors of all pathways are used to rank the pathways before presenting them to the user . note that all pathways affected are presented regardless of their impact factors . in figure 1 , for example , the pathway selected as the most important had only three differentially regulated genes out of 209 genes
. however , this pathway is dramatically impacted if the two transmembrane receptors and the ligand shown are affected .
the onto - tools suite is composed of an annotation database and six seamlessly integrated , web - accessible , free data mining tools : onto - express , onto - compare , onto - design , onto - translate , onto - miner and pathway - express .
pathway - express is a new tool that allows to find out most interesting pathways for the input list of genes in addition to visualizing the interactions among the genes in the pathways . over the past year
, our database has been dramatically expanded to include various types of data from 12 new databases , including swiss - prot , trembl , pir - iproclass , epd , hgnc , genpept , omim , pdb , homologene , refseq and entrez gene .
the onto - tools database now integrates various types of data from 19 genomics databases .
in addition , our database is also enhanced with the integration of functional annotations of new organisms .
currently , oe supports functional profiling for 24 organisms and 17 types of input ids . onto - translate
was enhanced to provide a non - redundant and complete mapping from one type of identification system to any other type . using the custom design of the onto - tools database , onto - translate
pathway - express ( pe ) performs a pathway level impact analysis and orders the affected pathways in the decreasing order of their expected importance for the given condition ( panel 1 ) .
pe displays details about each pathway including : the source database , the total number of genes , etc .
panel 3 shows the gene symbols , expression values ( or fold changes ) , and gene names for the differentially regulated genes .
panel 4 contains details about each pathway , including all genes in the pathway with their perturbation factors and expression levels .
the input genes are highlighted in red color on the pathway diagram ( panel 5 ) . | ### Summary:
: the onto - tools suite is composed of an annotation database and six seamlessly integrated , web - accessible data mining tools : onto - express , onto - compare , onto - design , onto - translate , onto - miner and pathway - express .
the onto - tools database has been expanded to include various types of data from 12 new databases .
our database now integrates different types of genomic data from 19 sequence , gene , protein and annotation databases .
additionally , our database is also expanded to include complete gene ontology ( go ) annotations .
using the enhanced database and go annotations , onto - express now allows functional profiling for 24 organisms and supports 17 different types of input ids . onto - translate
is also enhanced to fully utilize the capabilities of the new onto - tools database with an ultimate goal of providing the users with a non - redundant and complete mapping from any type of identification system to any other type .
currently , onto - translate allows arbitrary mappings between 29 types of ids .
pathway - express is a new tool that helps the users find the most interesting pathways for their input list of genes . onto - tools
are freely available at . |
<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 incorporation and widespread use of total mesorectal excision ( tme ) as the standard mode of surgical resection of adenocarcinoma of the rectum has been the most important surgical development in outcomes improvement for this disease [ 1 , 2 ] . supervised teaching of tme , as well as the detailed pathological audit of resected specimens , has also led to better oncological results .
advances in surgical technique with the use of either advanced stapling or manual coloanal anastomoses have allowed for achieving continuity of the gastrointestinal tract at levels closer to the anal verge than those achieved historically .
the advent of adjuvant and neoadjuvant chemoradiotherapy has also increased local control of disease and in some instances has led to increased survival .
surgery for rectal cancer in recent years has focused on anatomic and functional preservation of the sphincter without compromising oncological outcomes .
radical surgical treatment of cancers in lower third of the rectum has traditionally included low anterior resection ( lar ) and coloanal anastomosis , and abdominoperineal resection ( apr ) .
historically , the decision - making for sphincter - saving procedures has been related to the distance between the tumor and the anal sphincter complex . in the 1980s ,
a distal margin of 5 cm was required . in the ensuing decades , the 2-cm - rule
this rule has been challenged , however , and currently a distal margin of 1 cm is accepted as being appropriate for optimal oncologic outcome .
this provides a greater proportion of rectal cancer patients with the possibility of sphincter preservation [ 7 , 8 ] .
recently , adequacy of the circumferential resection margin is being considered of equal , if not greater , importance in the risk of local recurrence of rectal cancer . in recent years
, intersphincteric resection ( isr ) has been proposed to offer sphincter preservation in patients with very low rectal lesions , as an alternative to apr . of note
, apr has consistently had higher rates of local recurrence rates ( up to 22% ) compared with lar [ 10 , 11 ] .
a literature search for relevant articles in the english language associated with intersphincteric resection ( isr ) between 2000 and 2012 was undertaken .
schiessel and colleagues initially described the technique of isr . during isr , a transanal division of the rectum , with removal of part or the entire internal anal sphincter ( ias ) after tme , is performed , thus obtaining an adequate distal margin .
when planning for proctectomy with isr for rectal cancer , careful patient selection is paramount .
tumor height , its relationship to each component of the sphincter complex , and the presence or not of regional lymph node or distal metastases needs to be evaluated . for this reason
preoperative evaluation by the surgeon by means of digital rectal exam and rigid proctoscopy provides information regarding the level of the distal edge of tumour relative to the anal anatomic component of interest , which varies among experts in the literature [ 13 , 14 ] .
anal anatomic components of interest include the anal verge , the dentate line and the anorectal ring .
specialized imaging is required to study the relationship of the ias and external anal sphincter ( eas ) with the tumour .
endorectal / endoanal ultrasound and magnetic resonance imaging ( mri ) are performed for this reason . in addition
, high - resolution mri is accurate at estimating the circumferential margin ; with an overall accuracy of 88% .
inclusion criteria for performance of isr include the following : tumours located 30 mm from anal verge;tumours located 15 mm from dentate line;tumours located 1 cm from anorectal ring;local spread restricted to the rectal wall or the ias;adequate preoperative sphincter function and continence;absence of distant metastases .
tumours located 30 mm from anal verge ; tumours located 15 mm from dentate line ; tumours located 1 cm from anorectal ring ; local spread restricted to the rectal wall or the ias ; adequate preoperative sphincter function and continence ; absence of distant metastases .
contraindications to the performance of isr are the presence of fecal incontinence , t4 lesions , undifferentiated tumors , as well as tumors invading the puborectalis and the external anal sphincter ( eas ) .
a significant number of patients may require neoadjuvant chemoradiation therapy . in a systematic review of isr involving 14 studies and 1289 patients who underwent isr by martin and colleagues , 44% of patients had stage iii disease and 38% underwent preoperative chemoradiation overall .
of note , in certain studies included in the review , preoperative radiation was a contraindication to performing isr due to possible adverse functional effects .
this is in contrast to a recent study by denost and colleagues in which 93% of patients undergoing isr received preoperative radiotherapy .
the principle of the isr technique is based on an anatomic dissection plane between the ias and eas .
the distal resection line may be at the intersphincteric groove ( total isr ) , between the dentate line and the intersphincteric groove ( subtotal isr ) , or at the dentate line ( partial isr ) .
additional maneuvers to reduce the risk of local tumor cell implantation include closure of the rectal stump , cytocidal washout , and pathological evaluation of the distal margin with frozen section analysis . the specimen is usually delivered per anum .
a hand - sewn coloanal anastomosis with construction of a colon j - pouch , transverse coloplasty , or straight anastomosis is performed .
certain groups , especially in japan , perform lateral pelvic lymph node dissection for tnm stage iii tumors .
a defunctioning temporary stoma is fashioned , which is closed 6 weeks to 12 months from the primary operation .
anastomotic leak was experienced after a mean of 9.1% , and the rate of pelvic sepsis was 2.4% . the rate of clinically apparent anastomotic leakage following stapled anastomosis following anterior resection is in the range of 315% .
anastomotic leakage is associated with postoperative anastomotic stricture , cancer recurrence , poor postoperative function , as well as increased operative mortality . in conclusion
, isr can be performed with acceptable rates of anastomotic leakage and low operative mortality .
radical surgical removal of the tumor is the only chance for permanent cure of rectal cancer , despite all progress in the development of oncologic therapy .
rullier and colleagues reported a local recurrence rate of 2% in a series of 92 patients undergoing isr .
most patients ( 78% ) had t3 lesions , and 88% underwent long - course neoadjuvant radiochemotherapy .
the overall 5-year survival rate was 81% , with a 5-year disease - free survival of 70% .
reported a similarly low 2.5% cumulative 5-year local recurrence rate , a 5-year disease - free survival rate of 83.5% for stage ii patients and 72% for stage iii patients .
the pooled rate of local recurrence was 9.5% with an average 5-year survival of 81.5% .
distant metastases occurred in 9.3% . in martin 's systematic review , the mean distal margin free from tumour was 17.1 mm , crm - negative margins were achieved in 96% of patients , and the overall local recurrence rate was 6.7% ( range : 023% ) .
the 5-year overall and disease - free survival rate was 86.3% and 78.6% , respectively .
rates of local recurrence following low anterior resection for the treatment of rectal cancer are commonly reported in the range of 2.632% following surgery alone .
therefore , the performance of isr for treatment of very low rectal cancer affords similar oncologic outcomes to those of conventional resections . moreover , saito et al .
similar local recurrence rates ( isr = 10.6% , apr = 15.7% , p = ns ) and 5-year disease - free survival ( isr = 69.1% , apr = 63.3% , p = ns ) were reported .
patients undergoing isr had significantly longer 5-year overall survival compared with patients undergoing apr ( isr = 80% , apr = 61.5% , p < 0.05 ) .
it is considered that the risk of local recurrence may be a function of circumferential margin involvement rather than distal margin involvement .
risk factors for local and distant recurrence after isr were reported by akasu et al . .
local recurrence rate was 6.7% and distant recurrence was 13% . in the multivariate analysis , risk factors for local recurrence included positive microscopic resection margins , focal d - differentiation of tumor ( tumor budding ) , and elevated preoperative levels of ca 19 - 9 ( > 37 u / ml ) .
the identified risk factors for distant recurrence were pn1 , pn2 disease , poor differentiation , and distance of tumor from anal verge , 2.5 cm .
an important goal of sphincter - preserving surgery is to reach acceptable quality of life levels by preserving fecal continence .
physiologic studies have shown that anal resting pressure is due to the ias for 55% , the hemorrhoidal plexus for 15% , and to the eas for 30% . total or partial excision of the ias is bound to affect continence .
subtotal excision of the sphincter was associated with significant reduction in resting but not squeeze pressure after isr . of note , there have been no studies assessing anorectal physiology and continence after neoadjuvant radiation and prior to isr . as an antithesis to an aphorism by the famed architect louis sullivan , in rectal cancer surgery ,
loss of a part of the sphincter complex , loss of the rectal reservoir , and radiation is bound to have adverse effect on continence and defractory function .
bretagnol and colleagues reported that fecal continence measured by both the kirwan and wexner scores was significantly worse after isr .
in addition , the need for antidiarrheal medication was higher in patients undergoing isr compared with patients that had undergone conventional coloanal anastomosis .
frequency , urgency , the wexner score , and the fecal incontinence severity index ( fisi ) were significantly improved following colonic j - pouch reconstruction compared with straight coloanal anastomosis . regarding quality of life ( qol ) , bretagnol et al .
used both the sf-36 and fecal incontinence quality of life ( fiql ) to compare qol between patients undergoing isr and conventional coloanal anastomosis .
there was no difference in the qol scores between isr patients and conventional coloanal anastomosis patients in the physical and mental subscales of the sf-36 .
in martin 's systematic review , the mean number of bowel movements per day was 2.7 . nearly half ( 51.2% ) of patients reported perfect continence , about a third ( 29.1% ) reported experienced fecal soiling , 23.8% had flatus incontinence , had 18.6% had urgency . in a large study assessing functional outcomes after isr , denost reported that half of the patients had a good functional result ,
39% had minor fecal incontinence , and 11% had major incontinence . in the same study ,
the only independent predictors of good continence were a distance of tumour greater than 1 cm from the anorectal ring and anastomosis higher than 2 cm from the anal verge .
these include partial isr ( when possible ) and construction of a colon j - pouch .
in order to be successful in treating rectal cancer , good oncologic outcome is the first priority . equally important is the achievement of an acceptable quality of life for the patient .
the avoidance of a permanent stoma and all of the concomitant morbidity associated with it may be of greater importance to the patient .
low anterior resection with intersphincteric dissection and partial or total excision of the ias may be offered an alternative to apr in selected patients .
the functional outcomes after isr are expected to be inferior to those of conventional low anterior resection ; this information needs to be frankly communicated to the patient .
the morbidity , mortality , and oncological outcomes after isr are acceptable . careful patient selection and sound operative technique , with emphasis on high - quality preoperative imaging and functional assessment , should lead to superior results .
these principles have been closely examined at our own institution , and we have embarked on our first cases of intersphincteric resection in selected patients . | ### Summary:
: the treatment of rectal cancer has evolved from being solely a surgical endeavor to a multidisciplinary practice . despite the improvement in outcomes conferred by the addition of chemoradiation therapy to rectal cancer treatment , advances in surgical technique
have significantly increased rates of sphincter preservation and the avoidance of a permanent stoma . in recent years , intersphincteric resection for low rectal cancer has been offered and performed in patients as an alternative to abdominoperineal resection .
an overview of this procedure , including indications , oncological and functional results based on current literature , is presented herein . |
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: periodization of training workloads ( i.e. systematic variety in exercise frequency , intensity , duration , and mode over time ) is widely implemented for athletes ( 912 , 50 ) .
the goal of various periodization models is to develop appropriately timed peak performance , minimize risk of injury , and prevent overtraining to promote long - term adherence ( 20 , 27 , 30 , 51 ) . in a recent systematic review
, researchers suggest that periodized training has been safely implemented in sedentary adults , yielding improvements in relevant health and fitness outcomes ( 52 ) .
however , a major gap in this literature is that periodized approaches are rarely applied to aerobic exercise interventions . more research in this area
is warranted because , despite the documented health benefits , the majority of adults engage in insufficient volumes of aerobic activity ( 53 ) and long term adherence is poor ( 39 ) .
based on its successful application in athletes , it is possible that periodized aerobic exercise prescriptions may improve behavior to a greater degree compared to the relatively uniform prescriptions typically applied .
flexible nonlinear periodization ( fnlp ) is likely the most appropriate model to apply within sedentary populations . unlike other periodization models ( e.g. linear , undulating , block )
that is , acute bouts of exercise are matched in response to an individual s physical and/or mental readiness to train on a given day , such that more demanding workouts are completed in response to high readiness , and less demanding workouts are completed in response to low readiness ( 28 ) .
a variation is to allow individuals to choose which bout to complete ( from options ranging from low to high demand ) based on self - gauged perceptions of readiness .
while the practicality of such an approach is apparent , fnlp offers a means to apply relevant behavioral constructs .
first , allowing individuals to choose bouts may enhance perceptions of autonomy , which is associated with improved behavior in accordance with self determination theory ( 7 ) .
second , by allowing individuals to match bouts to pre - exercise state ( e.g. avoiding high demand workouts on low readiness days ) , fnlp - based prescriptions may promote more positive affective responses ( e.g. degree of pleasure or displeasure ) .
a growing body of literature suggests that imposing exercise workloads has a negative impact on in - task affect ( 15 , 32 , 56 ) , which predicts lower exercise in the future ( 57 , 58 ) .
while these hypotheses have yet to be empirically tested in the context of fnlp , a previous study ( 36 ) found that flexible goal - setting within a walking / jogging course for inactive adults ( i.e. modification of daily distance goal based on how individuals felt each day ) improved exercise behavior , compared to participants receiving fixed distance goals imposed by instructors .
although no information was provided regarding which feelings were measured or how they were assessed , this study lends some support for a flexible , participant - driven exercise prescription .
prior to adapting and implementing fnlp for aerobic training interventions , it is important to determine an appropriate marker of readiness . to date , two published studies have implemented fnlp for resistance training ( 37 , 38 ) .
both recruited inactive college students , allowing them to choose pre - determined bouts of resistance exercise based on their energy level rated on a scale from 0 ( no energy ) to 10 ( fully motivated with maximum energy ) .
while no rationale was explicitly provided for this scale , assessment of energy level may be considered a potential means of condensing kraemer and fleck s six - step approach to determine readiness introduced in their foundational text ( 28 ) .
these steps include 1 ) interactions with the trainee , 2 ) injury status , 3 ) hydration , 4 ) mental / physical fatigue ratings , 5 ) performance of a physical task ( e.g. vertical jump ) , and 6 ) initial performance of the assigned training workload .
it is reasonable to speculate that an individual s energy level would influence or be influenced by each of these components . although both studies noted significant physiological improvements ,
first , the low anchor only relates to energy , whereas the high anchor relates to both motivation and energy , which potentially reduces the construct validity of the measure .
second , neither study provided data indicating whether energy ratings were actually related to any acute performance variables or relevant psychological responses .
third , it is unknown whether this approach is translatable to aerobic exercise behavior as both studies addressed resistance training .
thus , while energy levels are a plausible marker of exercise readiness , more empirical evidence is necessary to demonstrate that these ratings are predictive of relevant psychological and behavioral aspects of aerobic exercise .
the theoretical basis of fnlp is that individuals reporting greater degrees of readiness are better suited to engage in higher demand bouts . in regards to aerobic exercise
, we hypothesize that higher energy levels should predict more positive affective responses during moderate - intensity treadmill walking .
energy was operationalized using the energy index ( ei ) , which is calculated by subtracting fatigue from vigor subscale scores of the profile of mood states ( poms ) .
first , poms vigor and fatigue scores show the greatest changes in response to exercise training ( 41 , 45 ) .
second , ei has been used in previous research studies aiming to measure changes in energy with exercise training stress and recovery ( 8 , 26 ) .
third , currently there is no measure validated to assess the construct of exercise readiness as it relates to fnlp .
thus , we chose to assess a measure of energy to be consistent with previous fnlp - based intervention research .
the primary purpose of the current study was to determine the ability of pre - exercise energy index to predict 1 ) affective responses during an imposed bout of moderate intensity aerobic exercise , and 2 ) mean intensity during a self - selected bout of aerobic exercise .
all procedures were approved by the university of tennessee institutional review board ( irb # 9521b ) regarding ethics and human subject s protection .
undergraduate and graduate university students were recruited as a convenience sample for this pilot study .
participants were recruited using flyer advertisements distributed throughout the university campus , email listservs , and classroom announcements .
individuals were considered eligible if they were between the ages of 18 and 35 years , had a measured body mass index ( bmi ) of less than 35 kg / m , and self - reported less than 90 minutes of structured , moderate - intensity aerobic activity per week ( or the metabolic equivalent ) .
additional exclusion criteria included one or more contraindications to beginning an exercise program according to the physical activity readiness questionnaire ( par - q ) , or pregnant / planning to become pregnant .
eligible participants completed an orientation visit that included baseline demographic and psychological trait questionnaires , measures of height and weight , and a graded exercise test to estimate maximal oxygen uptake ( vo2max ) .
participants then completed two additional visits occurring in a randomized order , with at least 48 hours between visits : 1 ) imposed intensity condition ( to determine ability of ei to predict affective responses to a standardized intensity , and 2 ) self - selected intensity condition ( to determine ability of ei to predict volitional intensity ) . during the baseline visit
, participants completed the following questionnaires to assess variables that may potentially influence behavioral and psychological responses during the study : basic demographic information ( age , gender ) , cohen s perceived stress scale ( pss ) , the behavioral regulations in exercise questionnaire-2 ( breq-2 ) , the physical activity enjoyment scale ( paces ) and the preference for and tolerance of exercise intensity questionnaire ( pretie - q ) . height and weight were measured using standard procedures to calculate bmi .
next , eligible participants were fitted with a heart rate monitor ( polar electro , lake success , ny ) and completed an incremental peak treadmill test to estimate vo2max .
this session also served to familiarize participants with treadmill walking , as well as in - task scales , prior to experimental sessions .
the exercise test followed a modified balke protocol , with heart rate ( hr ) and rating of perceived exertion ( rpe ) measured during the last 10 seconds of each minute .
after the first minute , the incline increased to 2% and continued increasing by 1% each minute , for a maximum of 25 minutes .
peak termination criteria included a recorded hr within 10 bpm of age - predicted maximal hr and > 18 on the borg rpe scale .
time on the treadmill with this protocol is highly correlated with vo2max in both men ( 43 ) and women ( 44 ) .
estimated vo2max was calculated using the formula : vo2max = 1.44 ( minutes on treadmill ) + 14.99 ( 43 ) .
following the graded exercise test , participants were scheduled to complete the two experimental conditions , imposed intensity and self - selected intensity , in a randomized order and separated by at least 48 hours . for both supervised exercise sessions , participants reported that they abstained from heavy exertion for 24 hours prior to each session , as well as alcohol and caffeine for at least four hours prior to each session .
pre - exercise ei was recorded immediately prior to the exercise bout . for both sessions
, heart rate was recorded each minute while rpe , and feeling scale ( fs ; measure of core affect ) were recorded immediately before exercise , during the last 10 seconds of each five - minute block , and immediately after exercise .
participants were blinded to the treadmill settings and time for both conditions by placing a custom - fit barrier to block to the display screen .
the imposed intensity condition included a 30-minute bout where treadmill speed was set to 3.3 mph at a grade that elicited a heart rate between 7075% of age - predicted hrmax ( moderate intensity ) .
intensity was based on age - predicted hrmax because the graded exercise test was designed to test peak capacity and true hrmax values were not determined .
mean fs was calculated using measurements taken at minutes 5 , 10 , 15 , 20 , 25 , and 30 .
the self - selected intensity condition included a 30-minute bout during which participants were allowed 10 seconds to self - select treadmill speed and/or grade using the handrail controls at minutes 0 , 5 , 10 , 15 , 20 , and 25 .
participants were given the instruction at this point you are allowed to adjust speed , grade , or both in the direction you prefer .
language that could potentially bias participants was avoided ( e.g. choose a setting that feels good ) .
minute - to - minute heart rates were averaged across the 30 minutes , and then divided by age - predicted maximal heart rate to determine average intensity of the bout , expressed as % hrmax .
participants were asked to consider how often they experienced stressful thoughts or feelings over the previous month ( e.g. , in the past month , how often have you been upset because of something that had happened unexpectedly ? ) .
the pss consists of 10 items rated by frequency on a 5-point likert scale ( 1=never , 5=very often ) ( 6 ) .
participants were be asked to rate how they feel at the present moment about physical activity in general .
the paces consists of 18 items that are rated on a 7-point likert scale with opposite descriptions at each end ( 1=i enjoy it or it makes me depressed , 7=i hate it or it makes me happy ) ( 25 ) .
participants were asked to indicate to what extent each of the items is true for them in general .
19 items were scored on a 5-point likert scale ( 0=not true for me , 2=sometimes true for me , 4=very true for me ) .
the breq-2 was scored by compiling separate mean subscale scores and by computing the relative autonomy index ( rai ) , with higher scores indicating more autonomy - driven regulation ( 35 ) .
the pretie - q was used to assess individual differences regarding the intensity of exercise preferred and the intensity that can be tolerated .
16 items were scored on a 5-point likert scale ( 1=totally disagree , 3= neutral , 5= totally agree ) ( 19 ) .
participants were asked describe how they felt immediately before each exercise session ( using the prompt right now ) to assess vigor and fatigue subscales of the profile of mood states .
items were rated by the extent to which each is felt using a 5-point likert scale ( 0= not at all , 1=a little , 2=moderately , 3=quite a bit , 4=extremely ) . the instruction right now can assess transitory psychological states ( 2 , 34 ) .
ei is calculated by subtracting the score for fatigue ( 7 items ) from that of vigor ( 8 items ) , with scores ranging between 28 and 32 .
this fs is an 11-point scale that assesses immediate affective feelings of pleasure and displeasure .
the fs ranges from 5 ( very bad ) to 5 ( very good ) with 0 ( neutral ) as the midpoint ( 24 , 46 ) .
rpe was measured on the 620 borg scale ( 7=very , very light , 9=very light , 11=fairly light , 13=somewhat hard , 15=hard , 17=very hard , 19=very , very hard ( 3 ) . prior to each exercise bout
, participants were instructed on how to rate rpe using the standard script supported by the american college of sports medicine .
all analyses were conducted using the statistical package for the social sciences ( spss , version 21 ; spss inc . , chicago il ) .
bivariate correlation analyses were completed in order to determine relationships between independent ( ei ) and dependent ( fs , self - selected intensity ) variables .
the first assessed the relationship between ei and mean fs during the imposed exercise condition .
the second assessed the relationship between ei and average intensity ( % hrmax ) during the self - selected condition .
all procedures were approved by the university of tennessee institutional review board ( irb # 9521b ) regarding ethics and human subject s protection .
undergraduate and graduate university students were recruited as a convenience sample for this pilot study .
participants were recruited using flyer advertisements distributed throughout the university campus , email listservs , and classroom announcements .
individuals were considered eligible if they were between the ages of 18 and 35 years , had a measured body mass index ( bmi ) of less than 35 kg / m , and self - reported less than 90 minutes of structured , moderate - intensity aerobic activity per week ( or the metabolic equivalent ) .
additional exclusion criteria included one or more contraindications to beginning an exercise program according to the physical activity readiness questionnaire ( par - q ) , or pregnant / planning to become pregnant .
eligible participants completed an orientation visit that included baseline demographic and psychological trait questionnaires , measures of height and weight , and a graded exercise test to estimate maximal oxygen uptake ( vo2max ) .
participants then completed two additional visits occurring in a randomized order , with at least 48 hours between visits : 1 ) imposed intensity condition ( to determine ability of ei to predict affective responses to a standardized intensity , and 2 ) self - selected intensity condition ( to determine ability of ei to predict volitional intensity ) . during the baseline visit
, participants completed the following questionnaires to assess variables that may potentially influence behavioral and psychological responses during the study : basic demographic information ( age , gender ) , cohen s perceived stress scale ( pss ) , the behavioral regulations in exercise questionnaire-2 ( breq-2 ) , the physical activity enjoyment scale ( paces ) and the preference for and tolerance of exercise intensity questionnaire ( pretie - q ) . height and weight were measured using standard procedures to calculate bmi .
next , eligible participants were fitted with a heart rate monitor ( polar electro , lake success , ny ) and completed an incremental peak treadmill test to estimate vo2max .
this session also served to familiarize participants with treadmill walking , as well as in - task scales , prior to experimental sessions .
the exercise test followed a modified balke protocol , with heart rate ( hr ) and rating of perceived exertion ( rpe ) measured during the last 10 seconds of each minute .
after the first minute , the incline increased to 2% and continued increasing by 1% each minute , for a maximum of 25 minutes .
peak termination criteria included a recorded hr within 10 bpm of age - predicted maximal hr and > 18 on the borg rpe scale .
time on the treadmill with this protocol is highly correlated with vo2max in both men ( 43 ) and women ( 44 ) .
estimated vo2max was calculated using the formula : vo2max = 1.44 ( minutes on treadmill ) + 14.99 ( 43 ) . following the graded exercise test , participants were scheduled to complete the two experimental conditions , imposed intensity and self - selected intensity , in a randomized order and separated by at least 48 hours . for both supervised exercise sessions , participants reported that they abstained from heavy exertion for 24 hours prior to each session , as well as alcohol and caffeine for at least four hours prior to each session .
pre - exercise ei was recorded immediately prior to the exercise bout . for both sessions
, heart rate was recorded each minute while rpe , and feeling scale ( fs ; measure of core affect ) were recorded immediately before exercise , during the last 10 seconds of each five - minute block , and immediately after exercise .
participants were blinded to the treadmill settings and time for both conditions by placing a custom - fit barrier to block to the display screen .
the imposed intensity condition included a 30-minute bout where treadmill speed was set to 3.3 mph at a grade that elicited a heart rate between 7075% of age - predicted hrmax ( moderate intensity ) .
intensity was based on age - predicted hrmax because the graded exercise test was designed to test peak capacity and true hrmax values were not determined .
mean fs was calculated using measurements taken at minutes 5 , 10 , 15 , 20 , 25 , and 30 .
the self - selected intensity condition included a 30-minute bout during which participants were allowed 10 seconds to self - select treadmill speed and/or grade using the handrail controls at minutes 0 , 5 , 10 , 15 , 20 , and 25 .
participants were given the instruction at this point you are allowed to adjust speed , grade , or both in the direction you prefer .
language that could potentially bias participants was avoided ( e.g. choose a setting that feels good ) .
minute - to - minute heart rates were averaged across the 30 minutes , and then divided by age - predicted maximal heart rate to determine average intensity of the bout , expressed as % hrmax .
participants were asked to consider how often they experienced stressful thoughts or feelings over the previous month ( e.g. , in the past month , how often have you been upset because of something that had happened unexpectedly ?
the pss consists of 10 items rated by frequency on a 5-point likert scale ( 1=never , 5=very often ) ( 6 ) .
participants were be asked to rate how they feel at the present moment about physical activity in general .
the paces consists of 18 items that are rated on a 7-point likert scale with opposite descriptions at each end ( 1=i enjoy it or it makes me depressed , 7=i hate it or it makes me happy ) ( 25 ) .
participants were asked to indicate to what extent each of the items is true for them in general .
19 items were scored on a 5-point likert scale ( 0=not true for me , 2=sometimes true for me , 4=very true for me ) .
the breq-2 was scored by compiling separate mean subscale scores and by computing the relative autonomy index ( rai ) , with higher scores indicating more autonomy - driven regulation ( 35 ) .
the pretie - q was used to assess individual differences regarding the intensity of exercise preferred and the intensity that can be tolerated .
16 items were scored on a 5-point likert scale ( 1=totally disagree , 3= neutral , 5= totally agree ) ( 19 ) .
participants were asked describe how they felt immediately before each exercise session ( using the prompt right now ) to assess vigor and fatigue subscales of the profile of mood states .
items were rated by the extent to which each is felt using a 5-point likert scale ( 0= not at all , 1=a little , 2=moderately , 3=quite a bit , 4=extremely ) . the instruction right now can assess transitory psychological states ( 2 , 34 ) .
ei is calculated by subtracting the score for fatigue ( 7 items ) from that of vigor ( 8 items ) , with scores ranging between 28 and 32 .
this fs is an 11-point scale that assesses immediate affective feelings of pleasure and displeasure .
the fs ranges from 5 ( very bad ) to 5 ( very good ) with 0 ( neutral ) as the midpoint ( 24 , 46 ) .
rpe was measured on the 620 borg scale ( 7=very , very light , 9=very light , 11=fairly light , 13=somewhat hard , 15=hard , 17=very hard , 19=very , very hard ( 3 ) .
prior to each exercise bout , participants were instructed on how to rate rpe using the standard script supported by the american college of sports medicine .
all analyses were conducted using the statistical package for the social sciences ( spss , version 21 ; spss inc . , chicago il ) .
bivariate correlation analyses were completed in order to determine relationships between independent ( ei ) and dependent ( fs , self - selected intensity ) variables .
the first assessed the relationship between ei and mean fs during the imposed exercise condition .
the second assessed the relationship between ei and average intensity ( % hrmax ) during the self - selected condition .
mean exercise intensity fell within the ranged prescribed for the imposed condition with low variability ( range : 70.6074.70% hrmax ) .
while mean intensity was similar for the self - selected condition , a higher inter - individual variability was noted ( range : 54.2392.63% hrmax ) .
inter - individual variability was also relatively high for pre - exercise ei in both conditions ( imposed range : 11 to 27 , self - selected range : 11 to 26 ) .
bivariate correlation analyses indicated that ei was strongly and positively correlated with mean fs ( r=.569 , p=.002 ) but not bout intensity expressed as % hrmax ( r=.224 , p=.262 ) , as indicated in figure 1 .
the potential heteroscedastic relationship between ei and fs was objectively tested using both the glejser and breusch - pagan methods and no concerns were noted ( glejser p=0.38 , breusch - pagan p=0.62 ) .
the first regression examined the relationship between ei , mean fs during imposed exercise that was standardized at moderate intensity across participants .
the second regression examined the relationship between ei and intensity ( mean % hrmax ) across the self - selected bout .
after adjustment for age , bmi , vo2max , rai , pss , paces , and pretie - q , ei was significantly associated with mean fs ( =.499 , p=.037 ) measured during imposed exercise .
no significant associations were found between ei and self - selected intensity represented as % hrmax ( =.121 , p=.554 ) .
the aim of the current study was to determine the ability of pre - exercise energy level to predict relevant affective ( feeling scale ) and behavioral ( self - selected exercise intensity ) outcomes surmised to be impacted by one s readiness to exercise .
when controlling for relevant factors , greater pre - exercise ei predicted more positive affective responses during imposed intensity exercise .
however , no significant relationship was found between ei and self - selected exercise intensity ( p=.554 ) .
average values regarding affective responses to moderate - intensity aerobic exercise and self - selected exercise intensity aligned with prior research ( 15 , 16 , 33 , 42 , 54 , 58 ) . in the current study , fs values suggest that individuals generally report positive , rather than negative , affective responses to imposed continuous moderate intensity aerobic exercise .
mean values reported here are similar to recent studies ( ranging between 2.6 and 3.0 ) ( 33 , 42 , 54 , 58 ) . similarly , average self - selected intensity fell within the range of moderate intensity , which has been demonstrated in prior research ( 15 , 16 ) .
mean ei values reported were lower relative to values observed in athletic populations prior to any overreaching training or acute event ( range between 14 and 18 ) ( 8 , 22 , 26 ) .
this disparity is expected , as healthy athletes tend to score higher on vigor and lower on fatigue , tension , depression , anger , and confusion , when compared to the general population ( i.e. the iceberg profile ) ( 40 ) .
it is also important to examine intra - individual differences in regards to physiological and psychological responses to exercise . the observed intra - individual variability in mean fs is in line with prior research ( 14 , 55 , 57 ) . of the individuals who completed the imposed exercise bout , 11% exhibited an increase in affect
, 63% exhibited a decrease in affect , and 26% indicated no change in affect , relative to pre - exercise fs .
corresponding values in the self - selected condition were found to be 11% , 67% , and 22% , respectively . regarding self - selected exercise intensity
, 19% bouts fell within the range for low intensity ( < 64% hrmax ) , 44% were moderate intensity ( 6476% hrmax ) , and 37% were high intensity ( > 76% hrmax ) .
such variability has also been observed with self - selected exercise intensity ( 17 ) .
given our observations of both mean and individual responses reflect previous research , we believe that the current study design was appropriate as an acute exercise readiness paradigm , given the relative lack of empirical evidence in this area of research . because only one out of the two hypotheses was supported in the current study , it is premature to suggest that measuring one s ei alone is a sufficient measure of exercise readiness as it relates to aerobic exercise for aerobically untrained young adults . given the aforementioned relationship between in - task affect and future exercise behavior ( 58 ) , the ability to predict such responses to moderate - intensity walking is important . first , walking is the most commonly reported mode of physical activity in american adults ( 23 ) .
second , moderate intensities are consistently prescribed , as they result in substantial health benefits and pose a lower risk of musculoskeletal injuries and acute cardiac events ( 1 )
. however , the practicality of using energy index within interventions for sedentary adults is unknown .
regard , using a measure of energy as the sole marker of readiness may not allow optimal implementation of a fnlp - based program in this population . given that exercise is a complex human behavior , influenced by interrelated physiological , psychological , and environmental factors ( 49 ) ,
although the primary analyses indicated no significant relationship between ei and mean self - selected intensity , further analyses revealed information that will inform future research aiming to optimize fnlp for aerobic exercise .
the current study utilized a randomized , counter - balanced design , as this approach is typically considered to be more robust .
although it has been suggested that inexperience may lead individuals to self - select higher intensities ( 16 ) , it is unclear how much experience or familiarization may be necessary to counter this effect . because 52% of the participants experienced a graded exercise test ( spanning low to high intensity ) and a 30-minute moderate intensity bout prior to being prompted to self - select treadmill settings , we examined the data for potential order effects .
individuals who completed the self - selected bout first ( n=13 ) chose higher intensities relative to individuals who completed the self - selected bout second ( n=14 ) ( 76.6010.02 vs. 69.868.92 % hrmax ; t=1.85 , p=.076 ) .
while this analysis was likely underpowered , it is striking to note that 54% of participants in the former group self - selected exercise that is characterized as high intensity based on heart rate responses , compared to 21% who choose high intensities in the latter group .
additionally , those who completed the self - selected condition first reported significantly less positive affective responses relative to those who completed it second ( 2.421.43 vs. 3.750.74 ; t=2.98 , p=.008 ) .
based on these observations , we conducted additional bivariate correlations within each subset of participants .
these analyses revealed that ei was significantly related to self - selected intensity in those who performed the bout first ( r=526 , p = .046 ) , and unrelated in those completing this bout second ( r = .049 , p=.867 ) . completing a peak graded exercise test allows individuals to experience a spectrum of intensities , but observations within these subsamples suggest that the duration spent at each intensity level may not be sufficient to inform subsequent self - selected sessions .
it appears that through experiencing a second , moderate - intensity bout , individuals were then able to self - select more pleasurable intensities in the final bout . while these finding oppose a previous study ( 48 ) wherein participants self - selected higher intensities when this bout was performed after an imposed bout both studies highlight a potential problem with counterbalancing order of visits and the need for additional familiarization sessions when assessing behavioral outcomes . perhaps more interestingly
is that , in those who completed the self - selected bout first , individuals with lower energy scores appear to have chosen relatively higher intensity bouts . to date , we can only speculate the underlying causes , but inexperience is likely to play a role .
one of the most commonly reported benefits of acute exercise is that it purportedly increases energy levels , which has been empirically supported by a recent meta - analysis ( 34 ) .
it is possible that this message has been internalized , such that participants in the current study aimed to use exercise as a means of feeling more energized .
however , an alternative possibility is that participants did not conduct any self - assessments in order to inform exercise decisions .
additionally , the researchers did not provide or interpret ei scores to participants and utilized a neutral prompt for self - selected exercise . combined with their relative inexperience with treadmill exercise
given the lower mean fs scores , we surmise that the latter possibility is more likely . in order to effectively implement fnlp - based practices in untrained adults
, it may be necessary to teach individuals how to assess and interpret physical / mental readiness to exercise and explicitly prompt them to choose workloads that match their acute state .
for a more in depth understanding of this phenomenon , future studies utilizing self - selected bouts would benefit from conducting qualitative assessments to determine factors involved in the behavioral choices of participants and test the impact of various prompting techniques .
such exploratory approaches are necessary to inform subsequent hypothesis - driven research in this area .
first , results are likely not generalizable across various other populations , aerobic exercise modes , or indices of volitional effort .
second , prior research has indicated that affective responses are most variable between individuals when exercising near ventilatory threshold ( vt ) ( 13 ) . because the current study did not assess vt , it is unclear whether ei can predict affective responses when intensity is set below , at , or above this physiological marker .
although setting aerobic intensity based on age - predicted hrmax has some inherent limitations ( 21 ) , this approach is the most feasible for prescribing exercise intensity when true maximal ( or vt ) values are unknown .
third , although the poms has been widely used in athletic populations ( 31 , 47 ) , it has received criticism , in that it was developed for use in clinical populations , is skewed toward negative mood states , and may lack sensitivity in detecting fluctuations in affective or mood states ( 4 , 18 ) .
thus , an important focus of future research is to operationally define exercise readiness and create validated measures of this construct .
while energy level as measured by the ei was predictive of affective responses to moderate - intensity aerobic exercise , hypotheses were not supported regarding self - selected intensity .
nonetheless , this research represents an important step in optimizing fnlp practices for aerobic exercise .
overall , adapting and implementing fnlp - based aerobic exercise prescriptions holds substantial promise as a means of promoting a more individualized , responsive program for untrained adults to improve long - term adherence .
such individualization is strongly promoted by the american college of sports medicine ( 21 ) .
additionally , the variability noted in ei , fs , and self - selected exercise intensity suggests that individuals , even those within a relatively homogeneous group in a controlled laboratory environment , do not respond uniformly to a given exercise prescription .
these findings lend some support for the need to implement participant - responsive exercise prescriptions , as outlined in the fnlp framework . | ### Summary:
: energy ratings have been used as a marker of exercise readiness ( i.e. pre - exercise physical / mental state indicating ability to perform ) within flexible nonlinear periodization ( fnlp)-based resistance training interventions .
however , empirical data is lacking regarding the utility of this approach for aerobic exercise .
the purpose of this study was to examine the ability of pre - exercise energy level to predict affective and behavioral responses to prescribed aerobic exercise .
participants consisted of 19 women and 8 men ( n=27 , age=204 years , estimated maximal oxygen uptake=376 ) . participants performed two 30-min bouts of treadmill exercise under an imposed moderate intensity ( 7075% of age - predicted maximal heart rate ; % hrmax ) condition and a self - selected intensity condition .
pre - exercise energy level was assessed using the energy index ( ei ) score derived from the profile of mood states .
feeling scale ( fs ) was the dependent variable in the imposed bout and average intensity ( % hrmax ) was the dependent variable during the self - selected bout .
multiple regression analyses were used to determine if ei predicted mean fs and % hrmax . after controlling for potential confounders ,
ei significantly predicted mean fs ( =.499 , p=.037 ) during imposed exercise .
no significant relationship existed between ei and overall intensity ( = 121 , p=.554 ) during self - selected exercise . while ei predicted
in - task core affect it was unrelated to self - selected intensity .
it is premature to suggest ei as an optimal predictor of exercise readiness in regards to aerobic exercise for aerobically untrained young adults .
more research is needed to determine an evidence - based marker of readiness that can be used for aerobic exercise prescribed within the context of fnlp . |
<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:
: only seven cases of necrotizing epiglottitis / supraglottitis have been reported in medical literature ; all in immunocompromised patients . the features and characteristics of necrotizing epiglottitis are discussed with review of all previously reported cases .
a 65-year - old male presented in the emergency department complaining of a two day history of dysphagia , dysphonia , neck pain and a sore throat ; that rapidly evolved to stridor and dyspnoea .
his past medical history included vascular sarcoma treated with above knee amputation and chemotherapy 10 years ago , non insulin dependent diabetes mellitus ( niddm ) as a result of chemotherapy and hypertension .
he was plethoric with tachycardia ( 116 bpm ) , hypertensive ( 136/92 mmhg ) and pyretic ( 38c ) .
neck palpation revealed 3 x 2 cm midline suprahyoid diffuse swelling with associated right sided level ii lymph nodes .
the patient was intubated in the theatre and direct laryngoscopy demonstrated an oedematous supraglottis with redundant patchy necrosis occluding the glottis .
subsequently he was transferred to intensive care unit and treated conservatively with dexamethasone and antibiotics ( table 1 ) .
daily nasal endoscopy findings showed progressive supraglottic soft tissue oedema , worsening necrosis , pooling of saliva and diminishing air leak around the orotracheal tube .
patient progression parameters the contrast ct scan of the neck was performed on day 4 ( fig 1 . ) , showing soft tissue oedema around the orotracheal tube , oropharynx and laryngopharynx extending from the posterior aspect of the hyoid bone down to the level of the thyroid cartilage .
the contrast ct scan of the neck performed on day 4 ; showing soft tissue oedema around the orotracheal tube , oropharynx and laryngopharynx on the same day , the patient was re - evaluated under general anaesthesia .
direct laryngoscopy revealed an extensive oedematous supraglottis with severe necrosis involving the laryngeal inlet , base of the tongue and right tonsillar bed .
surgical debridement was not possible without compromising the integrity of the larynx due to extensive necrosis .
subsequently a tracheotomy was performed with a limited exploration of the neck , showing only inflamed soft tissues in the anterior compartment .
after the operation , the diagnosis was revised to isolated necrotizing fasciitis of the larynx .
a combination of empirical antibiotic therapy was prescribed under guidance of microbiologist ( table 1 ) .
the antibiotic regimen made significant improvements in the laryngeal oedema ( fig 2 ) , resolution of necrosis and inflammation of the laryngopharynx .
laryngoscopy showing dramatic improvement to laryngeal oedema histology of the laryngeal tissue reported scanty viable tissue overgrown with bacteria and there was no evidence of neoplasm or fungal infection .
microbiology cultures isolated alpha haemolytic streptococcus pyogenes ( gas ) , characteristic of necrotising fasciitis .
gas was resistant cefotaxime , penicillin and tetracyclin and sensitive to vacomycin ( table 1 ) .
the blood cultures were persistently negative . on discharge ( 25 day of hospital stay ) , there was no dysphagia , dysphonia or dyspnoea .
it is a potentially fatal infection of the supraglottis and adjacent structures ( 1 ) .
the first case was reported in 1983 as an isolated necrosis of the epiglottis in a 21 year old female with lymphoid leukaemia ( 2 ) .
five adults with various immunodeficiencies ( 3 ) ; and two paediatric patients suffering from infection induced haemophagocytic lymphohistiocytosis and an hiv positive infant ( 4 ) .
alpha haemolytic streptococcus pyogenes is responsible for most of necrotising fasciitis in the head and neck region .
it is estimated that between 5 - 15% of normal individuals harbour the bacterium , usually in the respiratory tract , without signs of disease(5 ) .
as normal flora , s. pyogenes can infect when defences are compromised or when the organisms are able to penetrate the constitutive defences . when the bacteria are introduced or transmitted to vulnerable tissues
invasive toxigenic infections can result in necrotizing fasciitis , myositis and streptococcal toxic shock syndrome .
the clinical presentation of our patient s laryngeal necrosis was aggressive and there was poor response to first line antibiotic treatment .
the alpha haemolytic streptococcus pyogenes was isolated from the laryngeal biopsy cultures ; showing sensitivity only to vancomycin .
patient suffered from chemotherapy induced niddm with good glycaemic control , but he was healthy otherwise .
all previously reported cases in the literature resulted in post - necrosis partial or complete loss of larynx . in this case , the laryngeal necrosis was limited to the mucosa and there was no loss of laryngeal skeleton .
there are a number of reasons why the presenting patient had a complete recovery with an intact larynx .
secondly , the early identification of the necrosis and aggressive antibiotic regimen could limit the infection invasion and tissue destruction . | ### Summary:
: we report a case of an acute necrotizing supraglottitis in a healthy patient .
only seven cases of necrotizing epiglottitis / supraglottitis have been reported in medical literature ; all in immunocompromised patients . the features and characteristics of necrotizing epiglottitis are discussed with review of all previously reported cases . |
<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 non - dystrophic myotonic syndromes are a set of disorders targeting skeletal muscles , characterized by muscle stiffness following contraction or percussion .
the pathology is caused by mutations in genes encoding voltage - dependent chloride channels ( clcn1 gene , clc-1 protein ) or sodium channels ( scn4a gene , nav1.4 protein ) , which are expressed exclusively in skeletal muscles ( matthews et al . , 2010 ) .
loss - of - function mutations of clc-1 channels or gain - of - function mutations of nav1.4 channels pathologically increase sarcolemma excitability with occurrence of abnormal action potentials runs and consequent difficulties in muscle relaxation , determining the muscle stiffness characteristic of myotonic muscle .
today the pharmacotherapy of myotonic syndromes , resulting either from chloride or sodium channel mutations , is based essentially on the use of sodium channel blockers , which reduce sarcolemma excitability by inhibiting action potentials ( conte camerino et al . , 2007 ) .
the preferred drug is mexiletine , a class ib antiarrhythmic , used at rather high doses ( lehmann - horn et al . , 2008 ; matthews et al . , 2010 ) .
preferential binding to inactivated channels and use - dependent block are thought to constitute the basis of the selective action of mexiletine on pathologic hyperactive tissues .
however , not all the patients take benefits from mexiletine , which can induce side effects limiting patient compliance , including epigastric discomfort , nausea , tremor , anxiety and headaches .
. moreover lack of mexiletine efficacy has been observed in a number of patients , most probably in relation to pharmacogenetic mechanisms ( desaphy et al . , 2004 ) .
in addition , mexiletine has been withdrawn from the market in several countries . thus there is a critical need for the individuation of new efficient and safe antimyotonic drugs . in a previous study
, we showed that drugs known as modulators of -adrenergic receptors are able to block sodium channels in a manner reminiscent to local anesthetic drugs ( desaphy et al . , 2003 ) .
the 2-agonist clenbuterol and the -antagonist propranolol showed efficacies comparable to mexiletine in producing use - dependent inhibition of sodium currents in rat skeletal muscle fibers , as well as in tsa201 cells transiently expressing the human muscle sodium channel isoform , hnav1.4 .
in contrast , the -agonist salbutamol and the -antagonist nadolol had no effect on sodium currents at 1 mm concentration . examination of chemical structures and physicochemical properties of these drugs revealed the presence of the two pharmacophores important for sodium channel blocking activity , the tertiary amine and the aromatic ring , which confer respectively a high pka and a high lipophilicity .
however , the two inactive compounds are characterized by the presence of two hydroxyl groups on the aromatic moiety , which appeared to be determinant for impeding sodium channel blockade ( desaphy et al . , 2012 ) . accordingly
, clenbuterol was shown to inhibit action potential firing in skeletal muscle fibers , whereas nadolol did not ( desaphy et al . , 2003 ) .
in the present study , we evaluated in vivo the antimyotonic activity of these -adrenergic drugs compared to that of mexiletine .
for this , we have developed an animal model of myotonia allowing a quantitative preclinical study .
we have chosen to use a pharmacological model rather than the available genetic models , because it offers a large availability of animals , it allows to measure myotonia in a reproducible way through a non - invasive method , and it is cheaper . in this model ,
myotonia is induced in adult rats by a single intraperitoneal injection of anthracene-9-carboxylic acid ( 9-ac ) . by blocking muscle clc-1 channels , 9-ac is able to induce a myotonic state similar to chloride channel myotonia ( bryant and morales - aguilera , 1971 ; furman and barchi , 1978 ; estevez et al . , 2003 ) .
the myotonic state was evaluated by calculating the time of righting reflex ( trr ) , that is the time taken by the rat to turn back on his four limbs after being posted in supine position .
the results demonstrate that both clenbuterol and propranolol show a time - dependent antimyotonic effect in the dose range of 540 mg / kg , quite similar to that of mexiletine .
in contrast , either the 2-agonist salbutamol or the -antagonist nadolol , both unable to block sodium channels , did not show any significant antimyotonic effect .
we also demonstrated that both propranolol enantiomers produced undistinguishable hnav1.4 sodium channel block in vitro and antimyotonic activity in vivo .
we thus propose the r(+)-enantiomer of propranolol , which is inactive on -adrenoreceptors , as a possible alternative to mexiletine in the treatment of myotonic syndromes .
whole - cell sodium currents ( ina ) were recorded with patch - clamp technique in hek293 cells permanently transfected with the human skeletal muscle isoform of voltage - gated sodium channel , hnav1.4 ( desaphy et al . , 2012 ) .
sodium current recordings were performed at room temperature ( 2022 c ) using an axopatch 1d amplifier ( axon instruments , union city , ca , usa ) .
voltage clamp protocols and data acquisition were performed with pclamp 9.2 software ( axon instruments ) through a 12-bit a - d / d - a interface ( digidata 1340 , axon instruments ) .
pipettes made with corning 7052 glass ( garner glass , claremont , ca , usa ) had resistance that ranged from 1 to 3 mw .
currents were low - pass filtered at 2 khz ( 3 db ) by the four - pole bessel filter of the amplifier and digitized at 1020 khz .
after the patch membrane had been ruptured , a 25-ms - long test pulse to 30 mv from a holding potential of 120 mv was applied to the cell at a low frequency until stabilization of sodium current amplitude and kinetics was achieved ( typically 5 min ) .
only those data obtained from cells exhibiting series resistance errors < 5 mv were considered for analysis .
the experiments have been performed in accordance with the italian guidelines for the use of laboratory animals , which conforms with the european union directive for the protection of experimental animals ( 2011/63/eu ) , and received approval from the animal experimentation ethic committee of the university of bari - aldo moro ( cesa ) .
all efforts were made to minimize animal suffering and to reduce the number of animals used .
adult wistar rats ( 350500 g ) were purchased from charles river italy .
a total of 20 rats were housed individually and given food and water ad libitum . in a typical daily experiment ,
three / four rats were randomly extracted from this pool to receive an intraperitoneal injection of 30 mg / kg anthracene-9-carboxylic acid ( 9-ac ) ( fig .
ten minutes after 9-ac injection , the animals received drug or vehicle per os using an esophageal cannula ( fig .
myotonia state was assayed by measuring the time of righting reflex , that is the time taken by the rat to turn back on his four limbs after having been positioned in supine position .
the trr was determined 10 min before and 10 , 30 , 60 , 120 , and 180 min after 9-ac administration . at each time point , the trr was calculated as the average of 7 determinations to obtain a s.e.m .
a 1-min interval was respected between two measures to avoid any warm - up phenomenon . typically , a control rat takes less than 0.5 s to turn back on his limbs , whereas , 30 min after 9-ac injection , a myotonic rat shows a trr greater than 3 s ( fig .
is expected to reduce the trr with respect to the trr measured in the rat receiving drug vehicle only .
effect of 9-ac was maximal 30 min after injection and reversed spontaneously within 15 h. this protocol was used to evaluate the dose
a second protocol was used to evaluate the duration of antimyotonic effect of a single drug administration ; in this case , the exploratory drug was administrated 120 , 90 , 60 , or 30 min before 9-ac , and the trr ( mean of 7 determinations ) was measured 30 min after 9-ac .
this protocol was performed contemporaneously in 3 rats , one of which receiving 40 mg / kg mexiletine , an other receiving 40 mg / kg propranolol , and the third one receiving only vehicle . at the end of each experimental day , the tested rats were allowed a resting period of at least 48 h before to reintegrate the reserve pool . by the end of the study , animals were reinserted in the animal quarter . for each drug dose
, the protocols were repeated on three - to - six days in different rats , and the experimental points are given as the mean s.e.m .
statistical analysis was performed using one - way analysis of variance ( anova ) followed by ad - hoc bonferroni 's t test .
patch clamp pipette solution contained in mm : 120 csf , 10 cscl , 10 nacl , 5 egta and 5 hepes , and the ph was set to 7.2 with csoh .
bath solution for patch clamp recordings contained ( in mm ) : 150 nacl , 4 kcl , 2 cacl2 , 1 mgcl2 , 5 hepes and 5 glucose .
mexiletine hydrochloride , 9-anthracenecarboxylic acid ( 9-ac ) , salbutamol , clenbuterol hydrochloride , nadolol , dl - propranolol hydrochloride and its r(+ ) and s( ) enantiomers , hydrochloride salts , were purchased from sigma - aldrich ( milan , italy ) . for patch - clamp experiments , racemic propranolol and its single enantiomers
the patched cell was continuously exposed to a stream of control or drug - supplemented bath solution flowing out from a plastic capillary . for in vivo experiments , a solution of 2.4 g / l 9-ac was prepared each day in distilled water containing 0.3% bicarbonate ; the volume of i.p .
the choice of 9-ac dose was based on preliminary experiments , indicating 30 mg / kg as the lower dose producing a reproducible myotonia , assayed by trr , in 100% of treated rats ( not shown ) .
exploratory drugs were diluted at the desired concentration directly in physiological 0.9% nacl saline for oral administration of a volume close to 1 ml .
the choice of drug doses was based on the usual clinical dose of mexiletine in humans , that is 38 mg / kg a day .
thus we first tested 5 mg / kg mexiletine and other compounds , and then increased the dose up to 40 mg / kg to draw a dose response curve .
myotonia was induced in rats by intraperitoneal injection of 30 mg / kg 9-ac . soon after 9-ac injection
, the rats show evident stiffness and difficulties to move . nevertheless , the animals remained fully conscious and alert .
breathing appeared normal . when hearing an unexpected noise , the animals reacted by a jump on site but had great difficulties to move away due to muscle stiffness .
2a shows the time course of trr measured in a number of rats having received i.p . 9-ac and oral drug vehicle , according to the protocol described in fig .
ten minutes before 9-ac injection the trr was less than 0.5 s. the trr was dramatically prolonged to 2 s 10 min after 9-ac , and increased further to 4 s 30 min after 9-ac .
then the trr decreased gradually over time , being close to 1 s 3 h after 9-ac .
statistical comparison of trr mean values measured at each time point was performed using one - way anova followed by ad - hoc bonferroni 's t - test ( anova parameters : f = 96.35 ; k-1 = 5 ; n - k = 114 ; p < 0.0001 ) .
all trr mean values resulted significantly different from the others ( at least p < 0.04 ) , except trr ( 60 ) and trr ( 10 ) that show no significant difference .
the trr was fully recovered within 15 h after 9-ac injection ( not shown ) .
myotonia developed in all the tested rats with the same kinetics , and the individual responses of rats showed reasonable variability . quite similar variability in peak myotonia
was also observed between two 9-ac injection performed in a single rat on different days ( not shown ) .
importantly , we observed that the peak trr measured at time 30 min was linearly correlated to the trr measured at 10 min ( fig .
2b ) , suggesting that the trr measured at the 10 min - time point was a predictive indicator of the full response in each animal .
thus we normalized the trr ( t ) as a function of trr ( 10 min ) as shown in fig . 2c , as a useful maneuver to compare myotonia between rats receiving the various drugs or vehicle .
mexiletine is today considered a first - line drug in myotonic patients ( lehmann - horn et al . , 2008 ) , and exerted antimyotonic effect in vivo in the adr ( arrested development of righting response ) myotonic mouse ( de luca et al . , 2004 ) .
in 9-ac treated rats , oral mexiletine , 40 mg / kg , produced a drastic reduction of trr with respect to vehicle , as soon as 10 min after administration ( fig .
3a ) . statistical comparison of all the tested drugs and vehicle was performed at each time point using one - way anova followed by ad - hoc bonferroni 's t - test .
mexiletine reduced the trr ( 30 min ) by 77.8 2.2% ( n = 6 , p < 0.0001 ) .
the antimyotonic effect of 40 mg / kg mexiletine was still significant after 40 ( p < 0.0001 ) and 100 ( p < 0.005 ) minutes , but was minimal after 160 min .
actually , the absolute trr value remained quite constant over time in presence of mexiletine , suggesting that 40 mg / kg may be close to the maximal mexiletine efficient dose .
the reduction of trr ( 30 ) by mexiletine with respect to vehicle was 33.5 9.3% ( n = 4 , p < 0.005 ) , whereas antimyotonic effect disappeared as soon as 40 min after mexiletine administration .
the antimyotonic effect of 15 mg / kg mexiletine was also measured in 3 rats and was statistically significant 10 and 40 min after drug administration ( not shown ) . the dose
response relationship was constructed for antimyotonic effect of mexiletine on trr ( 30 ) ( fig .
3 legend ) indicated an half - maximal efficient dose ( ed50 ) of 12.2 2.3 mg / kg and a slope factor ( nh ) of 0.9 0.2 ( means s.e .
the antimyotonic activity of 2-adrenoceptor agonists , salbutamol and clenbuterol , and -antagonists , nadolol and propranolol , were tested in parallel to mexiletine ( fig .
mg / kg , both salbutamol ( n = 3 ) and nadolol ( n = 3 ) did not show any significant antimyotonic effect .
in contrast clenbuterol and propranolol induced antimyotonic effects quite similar to mexiletine , although with a reduced efficiency .
the trr ( 30 ) was reduced by 64.8 2.9% with propranolol ( n = 4 , p < 0.0001 ) and 62.8 2.9% with clenbuterol ( n = 4 , p < 0.0001 ) , and significant antimyotonic effect was also observed after 40 ( p < 0.0001 for propranolol and p
< 0.001 for clenbuterol ) and 100 ( p < 0.01 for propranolol and p < 0.05 for clenbuterol ) minutes . at 5
mg / kg , antimyotonic activities on trr ( 30 ) of propranolol and clenbuterol were lower than that of mexiletine but still statistically significant ( p < 0.05 for both drugs ) .
the ed50 values were 22.6 2.4 mg / kg ( nh = 0.8 0.1 ) for clenbuterol and 19.4 3.2 mg / kg ( nh = 1.0 0.2 ) for propranolol ( fig .
3c ) . to compare the duration of antimyotonic effect of mexiletine and propranolol , we modified the protocol as shown in fig . 4a .
the trr was measured only once , 30 min after 9-ac injection , but either drug ( 40 mg / kg ) or vehicle were orally administrated to different groups of animals at various time points from 150 to 10 min before trr measurement .
the trr values measured in drug - treated rats were normalized with respect to the trr measured in rat receiving the vehicle alone and reported as a function of time ( fig .
effect was maximum 10 min after drug administration , remained quite constant for 2 h , and dropped drastically after 150 min .
although propranolol is clinically used as a racemic mixture , a number of evidences indicate that only the s()-enantiomer displays -adrenoceptor antagonism and exerts hemodynamic effects in humans ( stoschitsky et al .
sodium channel blockade by propranolol has been demonstrated by us and others ( fischer , 2002 ; desaphy et al . , 2003 ; wang et al . , 2010 ; bankston and kass , 2010 ) , and both enantiomers appeared to exert a similar effect at least on cardiac sodium channels ( fischer , 2002 ; wang et al .
here we compared the effects of racemic propranolol and single enantiomers ( 100 mol / l ) on the skeletal muscle hnav1.4 sodium channel isoform expressed in hek293 cells .
5a illustrate the huge use - dependent block of hnav1.4 channels by r - propranolol .
the drug blocked sodium currents by 64.7 13.5% at 0.1 hz stimulation frequency and 92.9 2.9% at 10 hz ( n = 3 ) .
similar results were obtained with the 3 compounds , showing the lack of stereoselectivity for propranolol in blocking sodium channels ( fig .
the two single propranolol enantiomers were also tested in vivo for antimyotonic activity in the 9-ac treated rat .
we tested the dose of 15 mg / kg , which is close to the ed50 of racemic propranolol , in order to detect any potential difference between drugs efficacies .
both enantiomers reduced the trr ( 30 ) to the same extent of the racemic mixture .
in this study , we developed a new pharmacological in vivo rat model of myotonia congenita to evaluate the antimyotonic activity of mexiletine and -adrenergic drugs .
genetic animal models of myotonia include adr or mto ( a myotonic mutant mouse arisen spontaneously at the jackson laboratories ; heller et al . , 1982 ) mice , dogs , and goats ( matthews et al . , 2010
although these models have proven very useful for the understanding of the physiopathology of myotonia , their use for preclinical screening of drugs shows obvious limitations .
dogs and goats are difficult and expensive to breed in the laboratory and their use raises ethical issues . in the adr or mto mice , myotonia is inherited in a recessive mode and is very severe .
myotonia that develops very early after birth hampers normal animal growth , induces skeletal malformation , and significantly reduces life expectancy .
the myotonic mice are very delicate to manipulate and support repetitive exercise with great difficulty .
nonetheless , myotonic mice were successfully used , with many precautions , by us and others to test some antimyotonic drugs administrated by i.p .
injection ( aichele et al . , 1985 ; de luca et al . ,
because of their small size and extreme fragility , the use of an esophageal cannula for oral administration of drugs is quite difficult in myotonic mice .
one of the advantages of the rat model used in this study is indeed the possibility to use oral administration of drugs , which is the common way used by patients .
other advantages include the very limited stress held to rats , the easy standardization of protocols , the reduced number of animals needed to obtain experimental points , and the reduced costs of experimentation .
the aromatic monocarboxylic acids have been shown to produce myotonia in mammalian skeletal muscle by blocking muscle chloride channels , 9-ac being the most potent ( bryant and morales - aguilera , 1971 ; palade and barchi , 1977 ) .
doses of 9-ac , 5 or 8 mg / kg , in rats induces electromyographic myotonia as early as a few minutes after administration , including action and percussion myotonia as well as a warm - up phenomenon ( mrozek et al . , 1974 ; conte camerino et al . , 1989
a dose response curve was only performed in a single anesthetized goat , suggesting an ed50 close to 4 mg / kg 9-ac for percussion myotonia ( bryant and morales - aguilera , 1971 ) . in preliminary experiments , we tested 5 , 10 , and 30 mg / kg 9-ac using the trr test in a larger number of rats ( not shown ) .
although myotonia was observed at all the three doses , a consistent myotonic response ( maximal trr 30 min after 9-ac administration observed in 100% of the tested animals ) was observed only at the higher dose , that is less than 8 times the estimated ed50 in goats .
thus 30 mg / kg was the lowest dose inducing reproducible behavioral myotonia allowing an easy quantification by means of the non - invasive trr test .
the effects of 9-ac were fully reversible within 15 h , and no side effects were observed even after repeated administration .
we can note here that a myotonia - like state can be also obtained in vivo with chemicals affecting sodium channels , including veratrinic agents .
nevertheless , such a model may not be adapted to the current study because the veratrinic agents acts on both nerve and muscle sodium channels and may generate drug interaction with the exploratory compounds ( ulbricht , 1998 ) .
importantly , no toxic effect of 9-ac has been observed on action potentials recorded in isolated rat diaphragm muscle fibers at concentrations up to 25 times the ki for reduction of sarcolemma chloride conductance , indicating lack of direct effects of the drug on sodium channels as well as on resting membrane potential ( furman and barchi , 1978 ) . from these results
, we can conclude that an effect of 9-ac on nerve excitability is very unlikely in our experimental conditions .
up today , the study of potential countermeasures against myotonia induced by 9-ac has been performed only in vitro ( dengler and rudel , 1979 ; van lunteren et al . ,
. therefore one important novelty of the model described here is that drugs are tested in vivo in conscious animals .
the model as shown here may present some limitations , especially regarding long term studies aimed at testing repeated administration of drugs or sustained - release drug formulations , which would merit to be addressed in future experiments .
nonetheless , we were able to perform a quantitative analysis of dose - dependent acute effects of antimyotonic drugs in vivo .
mexiletine , the preferred drug in myotonic humans , produced a dose - dependent antimyotonic effect in the 9-ac treated rat , as expected .
the ed50 value for oral mexiletine in the myotonic rat ( 12 mg / kg ) is comparable to that measured in the adr mouse for i.p .
mexiletine , in which 5 mg / kg produced a 50% reduction of trr ( de luca et al .
when needed , treatment for myotonia relief may require up to 800 mg a day mexiletine ( dr .
mauro lomonaco , catholic university , rome , personal communication ) , which closely corresponds to the mexiletine ed50 found in the animal models .
the dose of 40 mg / kg appeared likely close to the maximal efficient mexiletine dose in the rat ; at this dose , mexiletine effects developed very rapidly and lasted for 2 h. higher doses were not tested because of risks of undesirable life - threatening side effects .
a number of evidences suggest that mexiletine effects are related to sodium channel blockade in vivo , thereby reducing over - excitability in myotonic fibers independently of the genetic origin .
our results confirm such hypothesis since clenbuterol , propranolol , and single propranolol enantiomers , which all display sodium channel blockade and action potential firing inhibition in vitro , exerted antimyotonic effects in vivo , whereas nadolol and salbutamol did not .
clearly , the antimyotonic effects of these compounds were not related to modulation of the -adrenergic pathway . despite clenbuterol and
propranolol showed greater efficiency in blocking hnav1.4 sodium channels in hek cells ( desaphy et al . , 2003 ) ,
such an apparent discrepancy may be due to differences in pharmacokinetics or to the inappropriateness of voltage clamp protocols used in cell lines .
indeed sodium currents were recorded in hek cells using a holding potential of 120 mv , which is more negative than muscle cell membrane potential , and a stimulation frequency of 10 hz , which is likely less than the frequency of action potential runs in the myotonic muscle fiber .
future studies will be performed to assess sodium channel inhibition in hek cells using more physio / pathological conditions . in our hands , the 2-agonist clenbuterol displayed more variable antimyotonic efficiency at lower doses and undesirable side effects at the highest dose , including generalized weakness and breathing difficulties ( not shown ) .
propranolol was safe of side effects and produced constant antimyotonic activity lasting two hours , such as mexiletine .
the propranolol ed50 was 19 mg / kg compared to 12 mg / kg for mexiletine . in the clinical setting , propranolol is used essentially for cardiovascular diseases at doses ranging between 80 and 320 mg a day , corresponding to a maximal dose of 5 mg / kg . it is possible that antimyotonic effect in humans may thus require dosages in the higher range .
it is noteworthy that sporadic cases of myotonia aggravation have been reported in humans with the use of 2-agonists as well as with -blocking adrenergic agents ( blessing and walsh , 1977 ; ricker et al . , 1978 ) , and
regarding propranolol , the inhibition of -adrenoceptor would favor muscle membrane depolarization , that is thought to facilitate myotonia .
although we never observed myotonia exacerbation by propranolol in the rat model , a valuable approach to avoid undesirable -adrenergic effects in the myotonic patients would be to use the single r(+)-enantiomer of propranolol , instead of the racemic mixture .
indeed the r(+)-enantiomer is 100 times less active on -adrenoceptor pathway than the s()-enantiomer ( barrett and cullum , 1968 ) , but both stereoisomers share a similar action on skeletal muscle sodium channels ( this study ) .
it should be noted that the side effects of r(+)-propranolol may be similar to those of mexiletine , including cns troubles or cardiotoxicity in patients with heart disease , since these effects may result from sodium channel blockade .
nevertheless , mexiletine use is commonly associated with gastrointestinal disturbances , especially nausea ( see for instance duff et al . , 1983 ) , that can significantly limit patient compliance or even fully exclude mexiletine therapy .
this latter effect may not be related to sodium channel blockade , since it is not consistently observed with other class i antiarrhythmic drugs .
interestingly , nausea has been only reported in a very limited number of patients receiving propranolol ( stephen , 1966 ) .
an other limit of mexiletine therapy may be the lack of response in a number of patients , which might stem from individual variations in drug pharmacokinetics or mutation - induced sodium channel mutation / polymorphism . in this case
for instance , flecainide has been shown to be efficient in a myotonic patient carrying the sodium channel v445 m mutation and resistant to mexiletine ( rosenfeld et al . , 1997 ) .
thus , r(+)-propranolol might be useful as an alternative to mexiletine in a number of unsatisfied myotonic patients . in conclusion ,
a recent systematic review has underscored the lack of sufficient randomized controlled trials of treatments for the non - dystrophic myotonias ( trip et al .
, 2006 ) . a controlled trial of mexiletine versus placebo started in late 2008 , and
such trials are difficult to perform , being hampered by the difficulty in quantifying myotonia and in recruiting adequate number of patients to reach statistical power ( matthews et al . , 2010 ) . in this context
, a preclinical model appears of great interest allowing a screening of compounds aimed at individuating the most promising drug to be tested in humans .
the pharmacological model described in this study may encounter all the requisites for such preclinical studies .
although mexiletine is considered as a first - line treatment in both sodium and chloride channel myotonias , a number of patients can not use this drug because of contraindications , side effects , or lack of efficacy . among the drugs tested in this study ,
the r(+)-enantiomer of propranolol may thus merit further investigation in humans with the aim of increasing the arsenal of available antimyotonic drugs .
last but not least , the ability of propranolol to reduce cell over - excitability suggests a possible therapeutic value of this drug in various conditions of neuron excitability disorders .
| ### Summary:
: the sodium channel blocker mexiletine is considered the first - line drug in myotonic syndromes , a group of muscle disorders characterized by membrane over - excitability .
we previously showed that the -adrenoceptor modulators , clenbuterol and propranolol , block voltage - gated sodium channels in a manner reminiscent to mexiletine , whereas salbutamol and nadolol do not .
we now developed a pharmacological rat model of myotonia congenita to perform in vivo preclinical test of antimyotonic drugs .
myotonia was induced by i.p .
injection of 30 mg / kg of anthracene-9-carboxylic acid ( 9-ac ) , a muscle chloride channel blocker , and evaluated by measuring the time of righting reflex ( trr ) .
the trr was prolonged from < 0.5 s in control conditions to a maximum of 4 s , thirty minutes after 9-ac injection , then gradually recovered in a few hours .
oral administration of mexiletine twenty minutes after 9-ac injection significantly hampered the trr prolongation , with an half - maximum efficient dose ( ed50 ) of 12 mg / kg .
both propranolol and clenbuterol produced a dose - dependent antimyotonic effect similar to mexiletine , with ed50 values close to 20 mg / kg .
antimyotonic effects of 40 mg / kg mexiletine and propranolol lasted for 2 h. we also demonstrated , using patch - clamp methods , that both propranolol enantiomers exerted a similar block of skeletal muscle hnav1.4 channels expressed in hek293 cells .
the two enantiomers ( 15 mg / kg ) also showed a similar antimyotonic activity in vivo in the myotonic rat . among the drugs tested , the r(+)-enantiomer of propranolol may merit further investigation in humans , because it exerts antimyotonic effect in the rat model , while lacking of significant activity on the -adrenergic pathway .
this study provides a new and useful in vivo preclinical model of myotonia congenita in order to individuate the most promising antimyotonic drugs to be tested in humans . |
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: majority of the cases of lymphangiomas are present at birth , 95% of the tumors arise before the age of 10 years ( watson and mccarthy ) .
88% of the lymphangioma appears by the end of the 2 year of life ( hill and briggs ) .
the most common intra oral site being tongue , while it also seen in the palate , buccal mucosa , gingival , and lips .
a cystic hygroma is a congenital multiloculated lymphatic lesion that can arise anywhere , but is classically found in the left posterior triangle of the neck .
microscopically cystic hygroma consists of multiple locules filled with lymph . in the depth , the locules are quite big , but they decrease in size toward the surface .
syndromes associated with oral lymphangiomas are : ( 1 ) turners syndrome , ( 2 ) noonas syndrome , ( 3 ) trisomies , ( 4 ) fetal hydrps , and ( 5 ) fetal alcoholic syndrome .
majority of the cases of lymphangiomas are present at birth , 95% of the tumors arise before the age of 10 years ( watson and mccarthy ) .
88% of the lymphangioma appears by the end of the 2 year of life ( hill and briggs ) .
the most common intra oral site being tongue , while it also seen in the palate , buccal mucosa , gingival , and lips .
a cystic hygroma is a congenital multiloculated lymphatic lesion that can arise anywhere , but is classically found in the left posterior triangle of the neck .
microscopically cystic hygroma consists of multiple locules filled with lymph . in the depth , the locules are quite big , but they decrease in size toward the surface .
syndromes associated with oral lymphangiomas are : ( 1 ) turners syndrome , ( 2 ) noonas syndrome , ( 3 ) trisomies , ( 4 ) fetal hydrps , and ( 5 ) fetal alcoholic syndrome .
a 14-year - old boy reported to the department of oral maxillofacial pathology , ( vinayaka mission dental college , salem ) with the chief complaint of swelling on left cheek region for the past 5 years .
previous history revealed that patient had swelling since birth and it was operated at age of 3 years through extra oral approach and a scar was present in the left cheek region [ figure 1 ] .
after which the patient was apparently normal , then at the age of 9 years again the swelling appeared in the same region , which was growing slowly and attained the present size of 4 3 cm [ figure 2 ] , and was not associated with pain .
no history of bleeding and pus discharge associated with the swelling , no history of swelling in other parts of the body . a diffused extra oral swelling present in the left cheek region of about 5 6 cm in size diffuse swelling in the occlusa line of left buccal mucosa extending anteriorly from the corner of the lip to the retromolar region posteriorly , surface of the swelling had pebble like surface intraoral examination showed a diffuse swelling measuring around 4 cm 3 cm in size in relation to occlusal line of left buccal mucosa extending anteriorly from the corner of the lip to the retromolar region posteriorly , surface of the swelling had pebble like appearance .
extraoral examination : a diffused extra oral swelling present in the left cheek region of about 5 6 cm in size ; anteroposteriorly extending - from the left corner of the mouth to the anterior preauricular region , superoinferiorly - from the left ala of the nose to lower border of the body of mandible , no dilated veins over the swelling no pulsation felt [ figure 1 ] skin is pinchable with no sinus and fistula formation . there is scar over the swelling due to previous surgery and measuring about 3 0.5 cm [ figure 3 ] .
scar present measuring about 3 0.5 cm a provisional diagnosis of intra oral lymphangioma of the buccal mucosa was established . a differential diagnosis of arteriovenous malformation .
an incisional biopsy was performed under local anesthesia and specimen was subjected to histopathological examination .
microscopically , it showed numerous dilated lymphatic vessels lined by thin endothelial cells , characteristically located just beneath the epithelial surface and spaces within the lymphatic vessels contain proteinaceous fluid [ figures 4 and 5 ] .
this superficial location results in the translucent , vesicle - like clinical appearance [ figure 2 ] .
the entire lesion was excised , no recurrence has been observed and the patient is under follow - up [ figure 6 ] .
numerous dilated lymphatic vessels lined by thin endothelial cells ( h and e , 10 ) numerous dilated lymphatic vessels characteristically located just beneath the epithelial surface and spaces within the lymphatic vessels contain proteinaceous fluid ( h and e , 40 )
intraoral examination showed a diffuse swelling measuring around 4 cm 3 cm in size in relation to occlusal line of left buccal mucosa extending anteriorly from the corner of the lip to the retromolar region posteriorly , surface of the swelling had pebble like appearance .
extraoral examination : a diffused extra oral swelling present in the left cheek region of about 5 6 cm in size ; anteroposteriorly extending - from the left corner of the mouth to the anterior preauricular region , superoinferiorly - from the left ala of the nose to lower border of the body of mandible , no dilated veins over the swelling no pulsation felt [ figure 1 ] skin is pinchable with no sinus and fistula formation .
there is scar over the swelling due to previous surgery and measuring about 3 0.5 cm [ figure 3 ] .
scar present measuring about 3 0.5 cm a provisional diagnosis of intra oral lymphangioma of the buccal mucosa was established . a differential diagnosis of arteriovenous malformation .
an incisional biopsy was performed under local anesthesia and specimen was subjected to histopathological examination .
microscopically , it showed numerous dilated lymphatic vessels lined by thin endothelial cells , characteristically located just beneath the epithelial surface and spaces within the lymphatic vessels contain proteinaceous fluid [ figures 4 and 5 ] .
this superficial location results in the translucent , vesicle - like clinical appearance [ figure 2 ] .
the entire lesion was excised , no recurrence has been observed and the patient is under follow - up [ figure 6 ] .
numerous dilated lymphatic vessels lined by thin endothelial cells ( h and e , 10 ) numerous dilated lymphatic vessels characteristically located just beneath the epithelial surface and spaces within the lymphatic vessels contain proteinaceous fluid ( h and e , 40 )
one theory is that the lymphatic system develops during the 6 week of embryogenesis from five primitive sacs that arise from the venous system . in the early 1900s
, sabin proposed that endothelial out pouchings from the jugular sac spread to form the peripheral lymphatic system .
godart , on the other hand , proposed that the lymphatic system developed from mesenchymal clefts in the venous plexus and spread centripetally toward the jugular sac .
the second theory is that lymph tissues are deposited in the wrong area during embryogenesis and subsequently fail to join the normal lymph system .
they are sometimes termed lymphaniectasia because they are cystic dilations of malformed lymphatic channels and therefore will collect lymph .
the most common presentation is that of painless soft mass that gradually enlarges and then remain static over a long period , occasionally enlargements and shrinkages occur , a residual mass remains .
due to their soft quality the clinical differential diagnosis include lipomas , salivary retention phenomena and hemangiomas .
many lymphangiomas have some blood in their lymphatic channels , they are most often confused with hemangiomas and are termed as hemangiolymphangioma , and these basically represent lymphangiomas with communication to normal blood vessels .
levin et al . have described lymphangiomas of the alveolar ridges of neonates in 3.7% of 1470 black neonates , these lymphangiomas forms blue domed , fluid filled swellings on the posterior crest of the alveolar ridge and posterior lingual surface of the mandibular ridge .
the superficial multicystic type is the most common type , it develop slowly as soft enlargements with pebbly surface .
the cystic hygroma type tends to expand outward , creating a generalized enlargement of the area .
this type is more often reported to undergo episodes of expansion and shrinkage than the other types .
histopathologicalically lymphangiomas with secondary hemorrhage are sometimes confused with cavernous hemangiomas , histologic features that favors the diagnosis of lymphangioma over hemangioma are more irregular lumens lined by spaced nuclei and proteinaceous material filling the lumen .
lymphatic endothelium express factor viii - associated antigen and cd31 and hence immunohistochemical procedures are not reliable means of distinguishing hemangiomas from lymphangiomas .
diagnostic workup includes biopsy for histopathologic examinations , which will confirm the diagnosis , ultrasonography will detect the cystic nature and fluid component of a lymphangioma and angiography will rule out vascular lesions .
although the lymphangioma is a benign lesion , it may cause significant morbidity due to its large size , critical location or proclivity to become secondarily infected .
the management of lymphangiomas includes early histopathologic diagnosis followed by surgical management and use of sclerosing agents .
the use of radiotherapy has declined because of the malignant transformation of previously irradiated lymphangiomas . | ### Summary:
: the lymphangioma are benign hamartomatous tumors of lymphatic vessels that arises from the sequestration of lymphatic that fails to communicate with the lymphatic system .
most common intra oral site being the anterior two - thirds of tongue , usually superficial in location and demonstrates a pebbly surface that resembles a cluster of translucent vesicles , they are typically soft and fluctuant masses .
secondary hemorrhage into the lymphatic spaces may cause some of these vesicles to become purple .
they have been known to grow to large size causing difficulties in mastication and speech .
a variant of lymphangioma is cystic hygroma grows as lymphatic anomaly found in the neck commonly present with significant airway obstruction .
we present a rare case of lymphangioma affecting the buccal mucosa of a 14-year - old male . |
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: diffuse dermal angiomatosis ( dda ) is a rare , acquired , reactive vascular proliferation , clinically characterized by livedoid erythematous violaceous plaques , which frequently evolve to ulceration and necrosis .
histopathologically , it is manifested by a diffuse proliferation of endothelial cells within the full thickness of the dermis .
we report a 63-year - old woman who presented with multiple erythematous violaceous plaques with central deep skin ulcers on thighs , lower abdomen , and perianal area , associated with intermittent claudication , low - grade fever , and weight loss .
initially , the clinical picture along with positive cultures for klebsiella pneumoniae suggested a multifocal ecthyma gangrenosum ; nevertheless , a skin biopsy showed a diffuse dermal proliferation of endothelial cells interstitially arranged between collagen bundles .
a computed tomography scan revealed severe aortic atheromatosis with complete luminal occlusion of the infrarenal aorta and common iliac arteries .
the patient underwent a left axillofemoral bypass surgery with a rapidly healing of the ulcers in the next weeks .
recognition of dda as a cutaneous sign of severe peripheral vascular disease is important for both dermatologists and internists .
recognition of risk factors and their management with an early intervention to correct tissue ischemia can be curative .
diffuse dermal angiomatosis ( dda ) is an unusual variant of cutaneous reactive angiomatoses ( cra ) , a group of benign vascular disorders characterized clinically by multiple , skin ulcers , developing on livedoid erythematous violaceous plaques , often arising in nonacral areas .
histologically dda is usually characterized by a diffuse dermal proliferation of endothelial cells and pericytes .
the pathogenic mechanisms are not fully understood but it is thought to correspond to a reactive process secondary to an underlying vascular occlusion .
we report a case of dda related to peripheral vascular atherosclerotic disease with successful evolution after revascularization .
in april 2015 , a 63-year - old woman presented to our department for evaluation of persistent multiple painful deep skin ulcers on the inner aspects of both thighs , lower abdomen , and perianal area that had appeared 1 month before consultation .
the development of these lesions was associated with intense pain , low - grade fever , and discrete weight loss ( 6 kg ) . over the past 2 months
her medical history was significant for heavy smoking , arterial hypertension , and dyslipidemia treated with enalapril and simvastatin .
physical examination disclosed multiple irregularly shaped retiform erythematous violaceous and purpuric plaques with central deep skin ulcers of undermined edges , ranging from 2 to 5 cm in diameter ( fig .
no peripheral pulses were noted in both lower extremities . no enlarged lymph nodes or signs of chronic venous insufficiency were detected .
laboratory test showed an increased leukocyte count ( 13.5109/l ) with neutrophilia ( 60% ) and raised c - reactive protein levels ( 11 mg
the rest of hematological , biochemical , and immunological surveys disclosed no abnormalities . a complete thrombophilic evaluation including lupus anticoagulant , anticardiolipin antibodies , leiden factor v , proteins s and c , antithrombin iii , antiphospholipid antibodies , cryoglobulin , fibrin degradation products , and d - dimer failed to detect any abnormality .
( a and b ) retiform erythematous violaceous plaques with central deep skin ulcers . a bacteriological culture from a 4-mm biopsy specimen obtained from the cutaneous ulcers isolated klebsiella pneumoniae , suggesting multifocal ecthyma gangrenosum as a possible diagnosis . antibiotic therapy with clindamycin and ciprofloxacin was prescribed without significant improvement .
after this treatment , bacteriological cultures yielded negative results . a biopsy specimen obtained from the abdominal erythematous plaque revealed a diffuse dermal proliferation of endothelial cells interstitially arranged between the collagen bundles involving the full dermal thickness .
the proliferating cells stained positively with vascular markers cd31 and cd34 and negatively for hhv-8 and d2.40 ( fig .
2 ) . a ct scan revealed severe aortic atheromatosis with complete luminal occlusion of the infrarenal aorta and common iliac arteries ( fig .
digital subtraction angiography ( dsa ) confirmed a complete aortic occlusion immediately below the renal arteries and also a complete occlusion of both iliac arteries with bilateral patent common , deep femoral and proximal superficial femoral arteries .
( a ) diffuse proliferation of endothelial cells involving the full dermal thickness , he 40. ( b ) endothelial cells interstitially arranged between the collagen bundles , he 100. ( c ) the specimen was positive for cd34 , stain at 200. cd34 = cluster of differentiation 34 , he = hematoxylin and eosin . ( a ) ct scan showing total aortic occlusion below the renal arteries .
patient 's ulcers continued to rapidly grow despite strict control of cardiovascular risk factors , daily treatment with 100 mg of acetyl salicylic acid and intensive local care . despite the surgical risk
, the patient underwent a left axillofemoral bypass surgery with a rapidly healing of the ulcers within 3 weeks after surgical intervention .
cra are a group of benign vascular disorders characterized histologically by different patterns of intravascular or extravascular proliferation of endothelial cells and pericytes .
violaceous , livedoid , poorly demarcated plaques , which may evolve toward necrosis and ulceration .
. the pathogenesis of cra has not been fully elucidated , but it is considered to represent a vascular endothelial growth factor ( vegf)-mediated reactive endothelial cell hyperplasia because of an underlying vascular occlusion .
a wide range of local and systemic disorders such as systemic infections ( mainly bacterial endocarditis ) , valvular cardiac disease , severe atherosclerosis , vascular insufficiency , cholesterol emboli , arteriovenous shunt , cryoglobulinemia , monoclonal gammopathy , cold agglutinins , lymphoproliferative diseases , rheumatoid arthritis , hepatopathies , and adrenal diseases have been incriminated as potential causative factors .
dda is an unusual variant of cra initially described in 1994 by krell et al .
it is characterized by a cutaneous diffuse proliferation of endothelial cells within the full thickness of the dermis , interstitially arranged between the collagen bundles with minimal intravascular involvement , usually associated with severe peripheral vascular atherosclerosis disease .
clinically dda is manifested by multiple , persistent skin ulcers , developing on retiform erythematous violaceous plaques , often arising in nonacral areas ( trunk , abdomen , proximal aspects of the extremities ) .
the lesions may be asymptomatic or painful and they tend to be persistent or enlarge progressively .
the diagnosis of dda should be suspected in patients with cardiovascular risk factors ( smoking history seems to be a strong risk factor ) who present persistent ulcerations in nonacral areas .
the characteristic histopathological features along the vascular surgical evaluation and imaging complementary explorations may permit to establish the definitive diagnosis .
the differential diagnosis should be established with the wide range of disorders manifested by retiform purpura secondary to microvascular occlusion , or by persistent deep necrotic ulcers such as bacterial and fungal infections , pyoderma gangrenosum , systemic vasculitis , or even lymphoproliferative disorders or calciphylaxis .
treatment should be based on the management of the underlying disease . in cases of peripheral vascular atherosclerotic disease ,
an increased awareness of physicians regarding dda as a potential causative disease of persistent multiple ulcerations seems to be important in order to avoid a diagnostic delay .
the suspicion of an underlying atherosclerotic disease should lead to a rapid evaluation of potential therapeutic options including revascularization , which may lead to complete resolution of the skin lesions . | ### Summary:
: abstractbackground : diffuse dermal angiomatosis ( dda ) is a rare , acquired , reactive vascular proliferation , clinically characterized by livedoid erythematous violaceous plaques , which frequently evolve to ulceration and necrosis .
histopathologically , it is manifested by a diffuse proliferation of endothelial cells within the full thickness of the dermis .
dda has been mainly associated with severe peripheral atherosclerosis.methods:we report a 63-year - old woman who presented with multiple erythematous violaceous plaques with central deep skin ulcers on thighs , lower abdomen , and perianal area , associated with intermittent claudication , low - grade fever , and weight loss .
initially , the clinical picture along with positive cultures for klebsiella pneumoniae suggested a multifocal ecthyma gangrenosum ; nevertheless , a skin biopsy showed a diffuse dermal proliferation of endothelial cells interstitially arranged between collagen bundles .
a computed tomography scan revealed severe aortic atheromatosis with complete luminal occlusion of the infrarenal aorta and common iliac arteries.results:the diagnosis of dda secondary to severe atherosclerosis was established .
the patient underwent a left axillofemoral bypass surgery with a rapidly healing of the ulcers in the next weeks.conclusions:dda should be considered in the differential diagnosis of livedoid ischemic lesions .
recognition of dda as a cutaneous sign of severe peripheral vascular disease is important for both dermatologists and internists .
recognition of risk factors and their management with an early intervention to correct tissue ischemia can be curative . |
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: liver transplantation ( lt ) may result in significant blood loss and subsequent transfusion of red blood cells ( rbcs ) in most patients .
although there is strong evidence supporting hemostatic defects in cirrhotic patients , many preoperative factors such as fulminant liver failure , bacterial infections , renal insufficiency , and severe portal hypertension may also cause imbalance in the hemostatic system .
in addition , anatomical local surgical difficulties , prolonged surgical time , perioperative hypothermia , metabolic derangements , and intraoperative dilutional coagulopathy ( blood transfusions and fluid administration ) are factors that could potentially increase blood loss during surgery . in the last decade , the experience acquired in the liver transplantation and management of jehovah 's witnesses patients where transfusions are not possible , the refinement of surgical techniques , and the appropriate anesthetic management has reduced intraoperative bleeding and the need for blood transfusions in the perioperative period during and following lt .
it is widely known that there is clear association between intraoperative rbc transfusion and survival in lt [ 4 , 5 ] .
certainly , significant surgical blood loss has been linked to major surgical morbidity and operative mortality , whereas rbc transfusion is associated with multiple disadvantages , risks , and increased financial burden .
furthermore , intraoperative operative blood loss independently predicts tumor recurrence and survival after radical surgery for hepatocellular carcinoma ( hcc ) .
although the triggering variable to administer rbc is mainly hemoglobin level , today there are no uniform criteria regarding how to prevent perioperative rbc transfusion in lt recipients .
there is still high variability between different centers in the use of fresh frozen plasma ( ffp ) , platelets , cryoprecipitate , fibrinogen , antifibrinolytic drugs , or desmopressin during perioperative period to prevent surgical bleeding .
other measures such as intraoperative cell saver and phlebotomy , as single or combined strategies , have been established only by few lt centers [ 8 , 9 ] . as a consequence of the deleterious effect of rbc transfusion during lt ,
herein , we report our experience with a series of patients receiving deceased donor lt without the need for perioperative red blood cells ( p - rbc ) transfusion and we evaluated their outcome .
between september 2006 and november 2011 , all patients who received deceased donor lt at our unit were analyzed using a prospectively collected database .
we divided the cohort in two groups according to the use of p - rbc transfusions : no - transfusion and yes - transfusion
( i.e. , when at least one p - rbc transfusion unit was transfused ) .
p - rbc transfusion was defined when one or more rbc units were transfused to the recipient during lt or within the first 48 hours following surgery .
the aim of our study was to assess the influence on early and long - term outcomes of using p - rbc transfusions in lt recipients .
we also evaluated donor and recipient factors that could independently predict the need for p - rbc transfusions .
we compared both groups according to patient , donor / graft , and perioperative variables .
organ procurement was performed as described elsewhere with aortic and portal perfusion using university of wisconsin preservation solution ( viaspan ; dupont , wilmington , de , usa ) .
marginal grafts were defined when three or more of the following criteria coexisted : cardiac arrest > 15 minutes or prolonged hypotensive episodes of < 60 mm hg for > 1 hour , donor age > 55 years , high vasopressor drug requirement ( dopamine dose > 10 g / kg / min or any doses of other amines ) , hypernatremia > 155 meq / l , prolonged intensive care unit ( icu ) stay ( i.e. , > 5 days with mechanic ventilation ) , elevated liver transaminases ( ast > 170 u / l or alt > 140 u / l ) , cold ischemia time > 12 hours , warm ischemia time > 40 minutes , and liver steatosis > 30% .
the following recipient data was collected : age , gender , history of previous upper abdominal surgery , underlying liver disease , biochemical profile , model for end - stage liver disease ( meld ) score , recipient status on the waiting list ( elective , emergency ) , surgical technique , and operative times .
all intra- and postoperative transfusion requirements ( rbc , ffp , cryoprecipitates , and platelets ) were recorded .
our anesthesiological strategy was focused on fluid restriction with low central venous pressure ( cvp ) during surgery .
maintenance fluids and crystalloids were administered to stabilize blood pressure > 90 mmhg and ensure diuresis of at least 0.5 ml / kg / h .
when fluid restriction was ineffective to keep a low cvp , vasoactive agents were used .
liver allograft function was evaluated clinically and through biochemical parameters such as aspartate aminotransferase ( ast ) , alanine aminotransferase ( alt ) , and bilirubin and prothrombin time measured daily during the first week .
liver graft vascular patency was evaluated by echo - doppler ultrasound during the first day and when clinically indicated .
primary nonfunction ( pnf ) of the graft was defined as death or retransplantation within 7 days following lt in the absence of any vascular problems .
primary dysfunction ( pdf ) of the graft was assumed when a peak ast level >
1.500 iu / l and a prothrombin time < 50% cooccurred within the first week of lt .
postoperative bacterial infection was defined as any clinical sign of infection in conjunction with positive bacteriological cultures within 30 days after surgery .
postoperative overall infection was defined as any documented infection ( i.e. , viral , bacterial , or fungal ) with positive serology or cultures within 30 days after surgery .
hepatocellular carcinoma and hepatitis c virus ( hcv ) recurrence were studied in each patient as recommended [ 14 , 15 ] .
all hcv recipients underwent 1-year protocol liver biopsy as part of our routine practice for early hcv recurrence diagnosis .
differences between groups were tested by chi - squared test for categorical and mann - whitney u - test for continuous variables .
multivariate analysis was performed using a logistic regression model to assess which factors were independently related to the need for p - rbc transfusions .
during the 62-month study period , 235 patients were included in our lt waiting list and , finally , 127 were successfully transplanted . among them , 46 patients ( 36% ) did not receive any intraoperative rbc transfusion but 7 of them were finally transfused with rbc units after the operation .
therefore , 39 ( 31% ) patients did not receive any p - rbc transfusions constituting the no - transfusion
group , and 88 ( 69% ) patients constituted the yes - transfusion group .
both groups were comparable regarding age , gender , body mass index ( bmi ) , history of previous upper abdominal surgery , cause of cirrhosis , diagnosis of hcc , diagnosis of hcv infection , and waiting list status ( table 1 ) .
group ( 11 versus 21 ; p < 0.0001 ) , the number of patients with meld score 25 was equivalent in both groups . moreover , only few patients received meld priority points due to early hcc in both groups ( 4 patients in the no - transfusion and 5 in the yes - transfusion ) .
preoperative biochemical profile showed that hematocrit , hemoglobin level , platelet count , and prothrombin time levels were significantly lower in
the number of patients transplanted using marginal grafts was equivalent in no - transfusion and yes - transfusion
in addition , variables such as cold and warm ischemia times and the presence of liver steatosis in each liver donor were equally distributed in both groups ( table 3 ) .
a full - size liver was implanted in 113 patients ( 89% ) and only 10 patients received a split liver graft .
as expected , median operative time ( 227 versus 240 min ; p = 0.02 ) and blood components transfusion were higher in the yes - transfusion
group ( table 4 ) . to note , intraoperative transfusion of rbc was not needed in 36% of our lt patients .
aprotinin infusion , cell saver , or phlebotomies were not used to reduce intraoperative bleeding or rbc transfusions in any circumstances .
the incidence of pnf , pdf , major complications , and biliary complications was the same in both groups ( table 5 ) .
however , hemodialysis need ( 0 versus 10% ; p = 0.01 ) , bacterial infections ( 10 versus 27% ; p = 0.03 ) , and postoperative overall infection rate ( 5 versus 22% ; p = 0.02 ) were significantly higher in the yes - transfusion group ( table 5 ) .
median icu ( 2 versus 3 days ; p = 0.003 ) , hospital stay ( 7.5 versus 9 days ; p = 0.01 ) , and prolonged hospital stay > 15 days ( 10 versus 27% ; p = 0.03 ) were also significantly higher in the group of patients needing p - rbc .
although 30-day mortality rate was higher in the yes - transfusion group ( 10 versus 15% ) , this difference was not significant ( table 5 ) .
interestingly , hcc recurrence after lt was only observed in the yes - transfusion group ( 0 versus 6 patients ; p = 0.12 ) , but without statistical relevance . although one- ( 86 versus 70% ; p = 0.09 ) and 3-year survival rates ( 77 versus 66% ; p = 0.09 ) were better in the no - transfusion group , this difference was not statistically significant ( figure 1 ) .
all preoperative donor , graft , and recipient data were included in a univariate analysis to determine variables that were unequally distributed in both groups of patients .
each significant variable was analyzed using a logistic regression model to assess which factors were independently associated with the need for p - rbc transfusions . baseline patient 's hemoglobin level before surgery ( p < 0.001 ) was the unique independent preoperative risk factor associated with p - rbc requirement . surprisingly , extended donor criteria , graft steatosis , and meld score were not a predictive factor for p - rbc transfusion in our series .
in contrast with transplantation of other organs , the intrinsic coagulopathy defects of lt candidates and the frequent presence of severe portal hypertension make transfusion - free surgery a major challenge .
most studies have focused on the deleterious effect of intraoperative massive blood transfusion without putting emphasis on the importance of avoiding transfusions in the early phase after lt [ 4 , 9 , 18 , 19 ] . to the best of our knowledge ,
this is the first study investigating the influence of using p - rbc on early and long - term outcomes after lt .
we observed that early outcome after lt is better with reduced bacterial infections , hemodialysis need , and overall infection rate when p - rbc transfusions are avoided .
surprisingly , neither donor / graft quality nor recipients meld score were predictive factors associated with the need for p - rbc transfusions .
as hemoglobin level was the only predictive factor in our cohort , maximum efforts should be placed on improving anemia in patients waiting for lt .
many strategies have been proposed for reducing intraoperative bleeding including the maintenance of a cvp 5 cm of water , reverse trendelenburg position , systemic infusion of nitroglycerin , and the use of antifibrinolytics agents , recombinant factor viia , or aprotinin [ 79 ] .
unfortunately , the clinical use of aprotinin has been questioned due to an increased incidence of renal failure , stroke , and myocardial infarction and it has been withdrawn from the market .
three randomized controlled trials ( rct ) demonstrated that the routine use of recombinant factor viia for patients undergoing lt is not recommended .
our policy based on maintenance of low cvp was used safely with minor hemodynamic disturbance in most patients
. however , to achieve this goal , a close communication between the surgical and the anesthesia team is crucial during transplant to delineate perioperative interventions targeted to minimize blood loss .
several studies have looked into factors that can predict transfusion requirements [ 9 , 2224 ] .
one study demonstrated a relationship between the starting platelet count , duration of surgery , the starting inr value , and the number of rbc units that were transfused during lt .
current organ allocation system in argentina is based on giving priority to the patients with the highest meld scores [ 25 , 26 ] .
usually , patients with high meld scores have poor coagulation status with reduced inr values and low platelet count related to hypersplenism .
although it could be expected that the need for intraoperative rbc transfusion can be predicted by the preoperative prothrombin time and degree of thrombocytopenia , we failed to confirm this in our cohort .
we observed that low baseline hemoglobin level was the only independent predictor for p - rbcs transfusion during lt .
in contrast with a previous study , we observed that donor and graft quality did not influence the need for rbc during lt .
hence , we believe that extramedical effort must be made to improve hemoglobin levels during waiting list time . in this scenario , many strategies can be considered during the waiting time so as to improve hemoglobin levels , such as administration of eritropoyetin , iron , and folinic acid , and in some situations even considering the use of rbc transfusions during waiting time to patients with hemoglobin levels 7 mg / dl . however , none of these strategies have been correctly validated in the field of lt and further analysis with well - designed rct is needed to support them .
unfortunately , the current literature review is unclear about the exact incidence of blood transfusions in lt .
while some reported routine rbc transfusions during lt , others made maximum efforts to minimize blood loss .
furthermore , there may be a bias towards underreporting due to lack of clear definitions of the perioperative period in this context and , perhaps , disinterest in the medical community on this topic .
however , the relationship between immunocompetence during the perioperative period and recurrence - free survival after lt is becoming a topic of interest , especially for patients with hcv infection or hcc . probably because this study is based on a small series , we failed to demonstrate any negative effect on viral or tumor recurrence in patients needing p - rbc .
the effect of novel anesthetic techniques and perioperative management on positively influencing the balance between inflammation and immune competence is an intriguing avenue for future studies .
thus , we urge transplant community to start reporting data on blood transfusions and to study its impact on clinical outcomes in patients undergoing transplant surgery .
apart from the obvious intraoperative life - saving benefits , there is accumulating evidence that rbc transfusions are associated with substantial complications after lt [ 9 , 18 ] .
the risk of allogeneic blood transfusion extends beyond viral transmission and includes allergic reactions , alloimmunization , bacterial sepsis , transfusion - related acute lung injury , renal failure , excessive intravascular volume , and immunosuppressive effects .
however , data are only related to the administration of blood components during surgery and scarce data has been published concerning its use during early postoperative time after lt . as probably intra- or early postoperative rbc transfusion could have a similar impact on outcome and considering that probably the reasons for differences on the administration timing or location could be mainly logistic , we decided to analyze transfusions during and within 48 hours after surgery .
interestingly , we found that only few patients were transfused after surgery demonstrating some kind of agreement between anesthesiologist and icu doctors . in agreement with others
, we observed that postoperative complication in terms of infections and hemodialysis need was increased in transfused patients .
we additionally confirmed that icu and hospital stay are longer in patients needing p - rbc transfusions . in the future
, a cost analysis of our rbcs - saving strategy will probably provide economic arguments for reducing perioperative transfusions that should be weighed against patient safety . in conclusion ,
poor donor / graft quality and high recipient meld score are not a predictive factor for p - rbc transfusion during lt .
patient requiring p - rbc transfusions had more complications in terms of higher infections and hemodialysis need , prolonging icu and hospital stays .
maximum efforts must be focused on developing novel strategies for improving hemoglobin levels during waiting list time to improve early outcome after transplantation . | ### Summary:
: background .
significant amounts of red blood cells ( rbcs ) transfusions are associated with poor outcome after liver transplantation ( lt ) .
we report our series of lt without perioperative rbc ( p - rbc ) transfusions to evaluate its influence on early and long - term outcomes following lt .
methods . a consecutive series of lt between 2006 and 2011 was analyzed .
p - rbc transfusion was defined as one or more rbc units administrated during or 48 hours after lt .
we divided the cohort in no - transfusion and yes - transfusion . preoperative status , graft quality , and intra- and postoperative variables were compared to assess p - rbc transfusion risk factors and postoperative outcome .
results .
lt was performed in 127 patients ( no - transfusion
= 39 versus yes - transfusion = 88 ) . while median meld was significantly higher in yes - transfusion
( 11 versus 21 ; p = 0.0001 ) group , platelet count , prothrombin time , and hemoglobin were significantly lower .
on multivariate analysis , the unique independent risk factor associated with p - rbc transfusions was preoperative hemoglobin ( p < 0.001 ) .
incidence of postoperative bacterial infections ( 10 versus 27% ; p = 0.03 ) , median icu ( 2 versus 3 days ; p = 0.03 ) , and hospital stay ( 7.5 versus 9 days ; p = 0.01 ) were negatively influenced by p - rbc transfusions . however , 30-day mortality ( 10 versus 15% ) and one- ( 86 versus 70% ) and 3-year ( 77 versus 66% ) survival were equivalent in both groups . conclusions .
recipient meld score was not a predictive factor for p - rbc transfusion .
patients requiring p - rbc transfusions had worse postoperative outcome .
therefore , maximum efforts must be focused on improving hemoglobin levels during waiting list time to prevent using p - rbc in lt recipients . |