Datasets:

AlvianKhairi

/

my-pandas-dataset-Abstract_No_Link_270k

like 0

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Comparison of intravenous oxytocin and prostaglandin E2 for induction of labour using automatic and non-automatic infusion techniques.? [/INST] A double blind trial of prostaglandin E2 and oxytocin given by intravenous infusion after amniotomy for induction of labour in 100 primigravidae with unfavourable induction features is reported. No clear-cut advantage of either drug emerged although PGE2 was perhaps superior when the cervix was highly unfavourable. Prostaglandin E2 appeared to produce less deleterious effects on the fetus but was associated with a higher incidence of maternal side effects. The automatic Cardiff Infusion apparatus was found to be a safe means of PGE2 infusion and to have advantages over the use of non-automatic techniques both for PGE2 and for oxytocin infusion. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The distribution within the placenta, myometrium, and decidua of 24Na-labelled hypertonic saline solution following intra-amniotic or extra-amniotic injection.? [/INST] 24Na-labelled hypertonic saline solution was injected into the uterus by the intra-amniotic or the extra-amniotic route, and six hours later determinations were made of the 24Na content of the placenta, myometrium, and decidua. The tissue specimens were obtained by subtotal hysterectomy. The activity of 24Na proved to be high in the decidua and in the fetal part of the placenta, but low in the myometrium. During labour, large amounts of prostaglandins have been found in the decidua, but little or none in the placenta. The present findings therefore lend further support to the assumption that hypertonic saline solution provokes abortion by inducing release of lysosomal phospholipase A2 into the cytoplasm of damaged decidual cells, resulting in prostaglandin synthesis and liberation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A study of the effect of bromocriptine on serum oestradiol, prolactin, and follicle stimulating hormone levels in puerperal women.? [/INST] Nine normal women were examined in the first 11 days of the puerperium. Serum prolactin, oestradiol and follicle simulating hormone (FSH) levels were measured and the FSH response to 100 mug of intravenously administered follicle stimulating hormone/lutenizing hormone-releasing hormone (LH/FSH-RH) was assessed on day 1 post partum in five subjects and on days 4 (two subjects), 6 and 7 post partum in the other four subjects. Bromocriptine therapy was given to six of these women and four to seven days after the start of such therapy, when prolactin levels had fallen to normal non-pregnant levels, these women were retested. Before bromocriptine treatment, the basal FSH levels were unmeasurable in six and low in one other of the nine subjects. After bromocriptine treatment, the basal FSH levels were measurable in four out of six patients and were higher than in the untreated patients (P less than 0-01). The FSH response to LH/FSH-RH was unmeasurable in eight out of nine before treatment, which is less than the response seen in 26 normal men and women (P less than 0-01). There was also no discernible FSH response to LH/FSH-RH after treatment with bromocriptine. Before treatment with bromocriptine, the serum prolactin levels were elevated in all nine women but were within the normal range for non-pregnant women after three days of bromocriptine therapy. Thus postpartum gonadotrophin suppression seemed to depend on high prolactin levels and at least part of the antigonadotrophic action of prolactin seemed to be at pituitary level. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of bromocriptine and chlorotrianisene on inhibition of lactation and serum prolactin. A comparative double-blind study.? [/INST] A double-blind study to compare the effect of 2-Br-alpha-ergocryptine (bromocriptine, CB 154, Sandoz) an ergot alkaloid with chlorotrianisene (Tace, Mer-National) on the inhibition of postpartum lactation was carried out in 38 women. At the dosages selected bromocriptine was more effective than chlorotrianisene in inhibiting lactation. Furthermore, bromocriptine significantly reduced serum prolactin levels to low normal values by the seventh day of treatment, whereas chlorotrianisene did not alter the normal progressive reduction in prolactin post-partum. Neither drug had significant toxic effects. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Structure of the modified nucleoside Q isolated from Escherichia coli transfer ribonucleic acid. 7-(4,5-cis-Dihydroxy-1-cyclopenten-3-ylaminomethyl)-7-deazaguanosine.? [/INST] The structure of the unknown modified nucleoside Q, which is present in the first position of the anticodons of Escherichia coli tRNA Tyr, tRNA His, tRNA Asn, tRNA Asp, is proposed to be 7-(4,5-cis-dihydroxy-1-cyclopenten-3-ylaminomethyl)-7-deazaguanosine (1). The structure of Q was deduced by means of its uv absorption, mass spectrometry, proton magnetic resonance spectroscopy, and studies of its chemical reactivity. The structure of Q is unique since it is a derivative of 7-deazaguanosine having cyclopentenediol in the side chain at the C-7 position. This is the first example of purine skeleton modification in a nucleoside from tRNA. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Sites of biological methylation of proteins in cultured chick muscle cells.? [/INST] The methylation of myosin and other proteins has been studied using primary cultures of 12-day-old embryonic chick leg muscle. The methyl group of [Me-3H] methionine is incorporated into basic amino acid residues with the formation of Nepsilon-monomethyllysine, Nepsilon-dimethyllysine, Nepsilon-trimethyllysine, 3-methylhistidine, NG-monomethylarginine, and NG-dimethylarginine which are isolated from acid hydrolysates of purified myosin, and of proteins from polysomes and from the cytosol of the cultured muscle cells. In the presence of 0.1 mM cycloheximide, incorporation of [Me-3H] methionine into the polysome-bound proteins was decreased to 16.3% of control levels with no change in the pattern of incorporation into the basic amino acid residues, although protein synthesis was inhibited 97.5%. When protein synthesis was allowed to resume in such cultures by the removal of cycloheximide, polypeptides containing labeled N-methylated residues were released from polysomes into the soluble fraction. Polypeptides containing N-methylated amino acids were also released from polysomes following treatment with 2 mM puromycin. Peptidyl-tRNA, isolated from ribosomes after exposure of cultures to [Me-3H] methionine, contained labeled N-methylated amino acids. When [Me-3H] methionine was incorporated in the presence of cycloheximide, the isolated peptidyl-tRNA still contained N-methylated amino acids although the amount of methylation was 22.4% of control levels. These experiments demonstrate that N-methylation of basic amino acid residues in proteins may occur while the polypeptide is still being synthesized on the ribosome. In addition, N-methylation can occur on the nascent polypeptides in the absence of protein synthesis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Molecular interactions between ribosomal proteins. Evidence for specificity of interaction between isolated proteins.? [/INST] The proteins S2, S3, S5, and S10 from the 30S ribosomal subunit of Escherichia coli was studied by analytical ultracentrifugation to characterize them in solution and to determine whether isolated protein-protein interactions exist. Such interactions, if specific, may therefore bear some relationship to the spatial organization of the subunit structure. It was found that protein S2 self-associates to a slight extent and that solution mixtures of S2 and S3 contain only enough dimeric species to account for the S2 dimer. Hence, no observable interaction was detected between S2 and S3. Solution mixtures of proteins S5 and S10 revealed a species of molecular weight greater than either protein. The proposal is that S5 and S10 interact with an association equilibrium constant of 7.6 X 10(-5) M-1 at 3 degrees in a Tris buffer at pH 7.4. It was also shown that solution with a 1:1:1 mixture by mass, of S2, S5, and S10 contained a species possessing a molecular weight consistent with a simple ternary complex of the three proteins. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about An immunological approach to the role of the low molecular weight subunits in myosin. II. Interaction of myosin and its subfragments with antibodies to the light chains.? [/INST] Immunological methods, in parellel with measurement of ATPase activity, have been used to characterize the reactions of antibodies specific for light chains with myosin and its water-soluble proteolytic subfragments, heavy meromyosin (HMM) and subfragment 1 (HMM S-1). Antiserum to the 5,5'-dithiobis(2-nitro-enzoic acid) (DTNB) light chain undergoes a precipitation reaction with all of the enzyme species, in which half of the homologous light chain is selectively dissociated. The results suggest that the incomplete dissociation reflects the way in which the light chain is bound, rather than the existence of two distinct species of DTNB 1.c. Little reaction was observed with antisera to alkali-released light chains, indicating that these components in myosin and the subfragments are either largely buried or else conformationally different from the isolated light chains used as immunogens. None of the antisera produced significant changes in Ca2+- or EDTA-ATPase activities. Moreover, calcium regulation through the troponin-tropomyosin system was unaffected by removal of DTNB 1.c. from myosin, as well as from the subfragments. The absolute level of actin-activated ATPase activity was, however, consistently lower in the presence of light chain antisera (or purified IgG and antibody) than in aqueous buffer or nonimmune serum. For both alkali and DTNB 1.c. antisera, this loss in activity seemed to result from steric hindrance of actin binding by antibody bound to undissociated light chain. Experimental conditions which would be expected to weaken such an antigen-antibody interaction, as well as the use of monovalent Fab in place of IgG, decreased the inhibition of activity. Altogether the activity measurements suggest that the light chains, particularly DTNB 1.c., are probably not integral parts of either the hydrolytic or actin-binding sites. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Evidence for photoinduced cross-linkage, in situ, of 30S ribosomal proteins to 16S rRNA.? [/INST] The effects of ultraviolet radiation on the 30S ribosomal subunit of Escherichia coli were studied. Irradiation in aqueous solution under anaerobic conditions resulted in a dose-dependent decrease in the separability of the rRNA and protein components of the 30S ribosomal subunit in 4 M urea-3 M LiC1. The results of gel filtration studies of the irradiated ribosomes before and after treatment with pancreatic ribonuclease indicated that the decrease in separability of the ribosome components was a result of the photoinduced formation of covalent RNA-protein cross-links. The number of covalent cross-links was estimated to correspond to less than 3 per 10,000 daltons of ribosomal proteins. One-dimensional gel electrophoresis studies of the course of the photoinduced cross-linkage reaction indicated that cross-linkage of individual 30S ribosomal proteins to the 16S rRNA proceeds in two dose-dependent steps. The first step requires an input of 1 X 10(20) quanta of 253.7 -nm radiation and results in the cross-linkage of at least five ribosomal proteins to the 16S rRNA. The second step requires a total input of 2 X 10(20) quanta of 253.7 -nm radiation, and results in the cross-linkage of most of the remaining 30S ribosomal proteins to the 16S rRNA. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A procedure for the rapid, large-scall purification of Escherichia coli DNA-dependent RNA polymerase involving Polymin P precipitation and DNA-cellulose chromatography.? [/INST] An improved method is described for the purification of the DNA-dependent RNA polymerase [ribonucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6] from Escherichia coli. The method involves lysozyme-sodium deoxycholate lysis, low-speed centrifugation, precipitation with Polymin P, elution from the Polymin P precipitate, ammonium sulfate precipitation, and chromatography on DNA-cellulose and Bio-Gel A 5m. RNA polymerase is purified to electrophoretic homogeneity in 2 days with a recovery of 45%, resulting in a yield of 250 mg of holoenzyme from 500 g of cells. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A fluorometric study of DNA-bound benzo[a]pyrene.? [/INST] Comparisons were made among the fluorescence spectra of DNA-bound benzo[a]pyrenes which were produced in vivo and in vitro. DNA from mouse skin treated with benzo[a]pyrene had a maximum emission beyond 400 nm, which was clearly distinguished from that of DNA-bound benzo[a]pyrene 4,5-oxide. The emission spectra from mouse skin were classified into two groups, type I and type II. The former was similar to the spectrum of benzo[a]pyrene, although the two maxima were shifted to longer wavelengths (410 and 435 nm). Type II was characterized by a broad peak around 430 nm. Type I and type II were obtained from different fractions of hydroxylapatite chromatography, but type I was changed into type II during storage. This suggests that type II is a modified product of type I. The emission spectra of both groups also were detected in in vitro activating systems, including photoirradiation, iodine treatment, and hydrogen peroxide treatment. Treatment of Escherichia coli with benzo[a]pyrene during culture produced only fluorescence of type I. Although the relationship between types I and II remains to be established, both types of fluorescence evidently indicate that the conjugated ring structure of the parent compound, benzo[a]pyrene, is preserved intact in DNA-bound benzo[a]pyrene. Several lines of evidence suggest that the proximate (active) form is an unidentified hydroxylated product including an oxy radical, but a cation radical cannot be completely excluded. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about On the mode of action of lomofungin, an inhibitor of RNA synthesis in yeast.? [/INST] Lomofungin is a potent inhibitor of RNA synthesis in yeast. Studies on the mode of action of the inhibitor were carried out using yeast RNA polymerases A and B and bacterial RNA polymerase. In vitro inhibition of RNA synthesis is independent of the nature and concentration of the template used and of the nucleoside triphosphate concentration. The extent of inhibition is strongly dependent upon the nature and concentration of divalent cations used to simulate transcription. The three RNA polymerases were inhibited to the same extent in the presence of Mn2+ ions whereas little inhibition was observed with Mg2+ ions. Spectrophotometric studies reveal the formation of different complexes between lomofungin and divalent cations (Mn2+, Mg2+, or Zn2+) with the respective stoichiometries of 0.5, 1, and 2 divalent cations per molecule of lomofungin. The complexes formed depend upon the nature of the divalent cation involved. No direct interaction between lomofungin and DNA could be observed in the presence of divalent cations but evidence is presented that lomofungin interacts with yeast RNA polymerase A. Inhibition of RNA synthesis occurs at the level of both chain initiation and elongation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about T7 RNA polymerase: conformation, functional groups, and promotor binding.? [/INST] Circular dichroic spectra of T7 RNA polymerase show minima at 222 nm ([theta]m=-7.9 X 10(3) deg cm2/dmol) and 208 nm ([theta]m =-7.55 X 10(3) deg cm2/dmol) and a maximum at 193 nm ([theta]m = 1.2 X 10(4) deg cm2/dmol). The small mean residue ellipticity above 200 nm indicates that the secondary structure contains approximately 12% alpha helix. The secondary structure is unaltered by high salt, glycerol, -SH reagents, nitration of tyrosyl residues, and chelating agents. Binding of the native enzyme to [32P]T7 DNA has been measured by the retention of the protein-[32P]DNA complexes on nitrocellulose filters. At 37degrees T7 RNA polymerase binds to its promoters in the absence of NTP's. Binding and catalytic activity are both abolished at 0degree. Binding of the initiating [gamma-32P]GTP can also be detected by the filter binding assay. Native T7 RNA polymerase is inactivated by reaction with 1 mol of 5,5'-dithiobis(2-nitrobenzoic acid) (Nbs2) or 1 mol of [14C]iodoacetamide. The latter reaction is blocked by Nbs2 suggesting that a single -SH group is required for activity. Alkylation of the -SH group does not alter binding of the enzyme to the DNA template, but modifies the binding of GTP to the enzyme. Nitration of approximately4 surface tyrosyl residues of the protein prevents binding to T7 DNA. The restriction endonuclease, Hpa II, cuts T7 DNA into approximately40 fragments and reduces total RNA synthesis by T7 RNA polymerase by 70%. Fragmentation of the DNA template by Hpa II does not alter the rate of RNA chain initiation by T7 polymerase, and restriction fragments accounting for approximately25% of the T7 DNA still bind tightly to the enzyme. Thus the T7 RNA polymerase promoters remain intact on the restriction fragments. Gel electrophoresis of the transcription products, using restriction fragments as templates, show that of the seven in vitro transcripts produced by T7 RNA polymerase from whole T7 DNA, only the smallest (representing the last 1.5% of the genome) is transcribed from Hpa II fragments. The remaining transcripts are replaced by six new and much shorter mRNA's. The DNA fragments containing the promoters for these mRNA's have been removed from the fragment mix by binding them to the enzyme and retaining the complexes on nitrocellulose filters. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Transcription of fractionated calf thymus chromatin by RNA polymerase of calf thymus and Escherichia coli.? [/INST] Calf thymus chromatin has been sheared and fractionated on sucrose gradients. Approximately 5-10% of the chromatin is resolved from the bulk of the imput chromatin as a slowly sedimenting fraction. The protein/DNA ratio of the slowly sedimenting fraction is not greatly different from the protein/DNA ratio of the more rapidly sedimenting chromatin fraction. Analysis of DNA of the chromatin fractions by CsC1 equilibrium density gradient centrifugation indicates that DNA of the slowly sedimenting fraction is depleted in the satellite DNA banding at 1.716 g/cm3. The template properties of the chromatin fractions have been examined with Escherichia coli RNA polymerase and form II and form III RNA polymerases of calf thymus. At rate-limiting concentrations, the slowly sedimenting fraction is twofold more active than the rapidly sedimenting fraction as a template for E. coli RNA polymerase. Homologous form II and form III RNA polymerases are respectively 30-fold and 16-fold more active with the slowly sedimenting fraction than the rapidly sedimenting fraction. The activity of form II RNA polymerase in transcribing the slowly sedimenting fraction exceeds its activity in transcribing an equal concentration of native DNA. Kinetic studies, in which RNA polymerase activity is assayed at various concentrations of chromatin, indicate that the greater activity of E. coli RNA polymerase with the slowly sedimenting fraction is due to an increased rate of transcription at saturating concentrations of template (Vmax), and is not due to a lower concentration required for half-maximal rate of transcription (Km). In contrast, the increased rates of transcription of the slowly sedimenting chromatin faction by the homologous polymerases are due to a decrease in concentration required for half-maximal rate of transcription rather than an increased rate of transscription at saturation concentrations of template. The relative degrease of satellite DNA in the slowly sedimenting fraction of chromatin and the enhanced template activity of the slowly sedimenting fraction suggest that this fraction is equivalent to nuclear euchromatin while the more rapidly sedimenting chromatin is equivalent to nuclear heterochromatin. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about L-phenylalanine:tRNA ligase of Escherichia coli K10. A rapid kinetic investigation of the catalytic reaction.? [/INST] The kinetics of the amino acid activation and the transfer of the amino acid to tRNA have been investigated for L-phenylalanine:tRNA ligase of Escherichia coli K10 by stopped-flow and radioactive techniques. The rapid kinetics were followed by the observation of the displacement of the fluorescent dye, 6-p-toluidinylnaphthalene-2-sulfonate from the binding site of L-phenylalanine under conditions where a single active site of the enzyme was involved. The following results are of particular interest. (1) Equilibrium binding of L-phenylalanine and tRNAPhe indicates in each case two sites of interaction with an approximately tenfold difference of the binding affinity. (2) Experimental conditions of the kinetic investigation were chosen to favor reactions at the high affinity binding sites. Under those conditions, the rate constants have been evaluated at 1 mM magnesium to be in the range 12-25 sec-1 for the activation reaction and 42-77 sec-1 for the reverse, the variation of the values depending on those of the dissociation constants used for computation. The rate constant for the transfer reaction is 0.05 sec-1 and for the reverse 0.19 sec-1. The forward reaction is rate limiting for the overall reaction at single turnover and steady-state conditions. (3) All rate constants depend on the concentration of magnesium. Evidence is provided that the transfer occurs via a productive enzyme-tRNAPhe complex which is in a magnesium-dependent equilibrium with an unproductive complex, high magnesium favoring the former. The position of the tRNA-CCA end in the productive complex is such, that the fluorescent dye can be displaced by Phe-tRNAPhe. The thermodynamics of the overall reaction have been treated on the basis of the partial reactions. The free enthalpy of the completed reaction was calculated to be very close to zero. The significance of the adenylate intermediate is discussed with respect to the product inhibition expected on the basis of the tendency of tRNAPhe and L-phenylalanine to form tight complexes with the enzyme. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Polynucleotide analogs: acrylic acid and maleic acid copolymers of 1-vinyluracil and 9-vinyladenine.? [/INST] Radical-induced copolymerization of 1-vinyluracil and maleic anhydride gave, after hydrolysis, a polymer containing a 1:1 monomer ratio of 1-vinyluracil-maleic acid. Gamma-Ray-induced copolymerization of 1-vinyluracil with acrylic acid gave a polymer with a ratio of 1:1.7. Similar treatment of 9-vinlyadenine and acrylic acid resulted in a polymer with a 1:3.2 ratio. These three compounds are potent stimulants of poly (uridylic acid) coded polyphenylalanine synthesis in an in vitro cell free system purified from Escherichia coli MRE 600. The double-stranded polymer, poly(inosinic acid)-poly(cytidylic acid), also stimulates polyphenylalanine synthesis in this assay. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Inactivation of rat liver RNA polymerases I and II and yeast RNA polymerase I by pyrodixal 5'-phosphate. Evidence for the participation of lysyl residues at the active site.? [/INST] Purified DNA-dependent RNA polymerase forms I (A) and II (B) from rat liver and form I from yeast are rapidly inactivated by pyridoxal 5'-phosphate at pH 8.0. The inhibition is relatively specific since pyridoxamine 5'-phosphate is not an inhibitor and pyridoxal is about 12 times less effective than pyridoxal 5'-phosphate. The inactivation is reversed by high concentrations of amines, and can be made irreversible by reduction with NaBH4. Spectral analysis of the inhibited enzyme and its NaBH4 reduction product indicates that a Schiff base forms between the aldehyde group of pyridoxal 5'-phosphate and one or more amino groups of the protein. Nepsilon-Pyridoxyllysine was identified as the only product in acid hydrolysates of the reduced yeast RNA polymerase I-pyridoxal 5'-phosphate complex. Complete inactivation of yeast polymerase I results in the incorporation of 3-4 mol of pyridoxal 5'-phosphate/1 mol of enzyme. DNA and nucleotide substrates partially protect the enzymes from inactivation. These results suggest that one or more lysyl amino groups are critical for the activity of animal RNA polymerases and show that pyridoxal 5'-phosphate is a suitable probe for studying the active sites of these enzymes. Comparison of the present results with those previously obtained with Eschericha coli RNA polymerase in this laboratory suggest a new degree of structural homology between eucaryotic and procaryotic RNA polymerases. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effect of salt on phospholipid fatty acid composition in Escherichia coli K-12.? [/INST] The fatty acid compositions of the three major phospholipids of Escherichia coli K-12; phosphatidylethanolamine, phosphatidylglycerol and cardiolipin; were determined during growth in media differing in NaCl concentration. Significant differences in fatty acid composition of the phospholipids were observed in the stationary phase cultures, but no appreciable differences were found in early exponential cultures. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Nitrogenases of Klebsiella pneumoniae and Azotobacter chroococum. Complex formation between the component proteins.? [/INST] 1. Sedimentation velocity analyses of mixtures of highly purified component proteins of Azotobacter chroococcum are consistent with the formation of a tight 1 : 1 complex in the absence of Na2 S2 O4. 1 : 1 complex formation between complementary proteins from A. chroococcum and Klebsiella pneumoniae was also observed. The addition of 5 mM Na2 S2 O4 weakened the interaction between the A. chroococcum proteins and also the interaction between complementary proteins of A. chroococcum and K. pneumoniae. 2. Steady-state kinetic data for acetylene reduction at low protein concentrations have been used to calculate association constants at 30 degrees C for the 1 : 1 protein complexes of nitrogenase proteins from A. chroococcum, K. pneumoniae and mixtures of complementary proteins from both organisms. Values centered around 3 - 10(7) M-1 were obtained. 3. The temperature dependence of the association constant for the complex formed by the K. pneumoniae proteins exhibited a sharp break at 17 degrees C with deltaH = 0 and deltaH = 418 kJ - mol-1 above and below 17 degrees C, respectively. 4. The Arrhenius plot for acetylene reduction by the complex formed by the K. pneumoniae proteins was linear over the range 12-40 degrees C with deltaH = 80 kJ - mol-1. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of L-azetidine 2-carboxylic acid on growth and proline metabolism in Escherichia coli.? [/INST] The effects of L-azetidine 2-carboxylic acid on growth and proline metabolism in a proline-requiring auxotroph of Escherichia coli are described. The homologue inhibited growth of the wild type and it, alone, did not substitute effectively for proline as a growth supplement for the mutant. In medium containing 0.05 mM proline, the addition of increasing amounts of homologue progressively inhibited growth of the wild type but stimulated growth of the mutant at homologue: proline ratios of 10 : 1 and 50 : 1. This suggested that the homologue exerted a "sparing effect" on proline in the mutant. The incorporation of L-[U-14C]proline and L-[3H]azetidine 2-carboxylic acid into hot trichloroacetic acid-insoluble material in the mutant was measured. Amino acid analysis of the insoluble material from cells incubated with radiolabeled proline alone revealed that proline was partially degraded and metabolized to other amino acids prior to incorporation into protein. The addition of unlabeled homologue to the incubation medium significantly reduced proline catabolism, suggesting that the homologue exerted a sparing effect on proline in this mutant. In medium containing unlabeled proline and radiolabeled L-azetidine 2-carboxylic acid, the homologue was incorporated both intact and partially degraded prior to incorporation into protein. Alanine was the major L-azetidine 2-carboxylic acid catabolite. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Multiple forms of mitochondrial alcohol dehydrogenase in Saccharomyces cerevisiae.? [/INST] Three forms of NAD-dependent alcohol dehydrogenase have been characterized in yeast by their heat sensitivity, their specificity and their electrophoretic patterns. Thermal stability increases in the following order: alcohol dehydrogenase I (fermentative enzyme), alcohol dehydrogenase II (oxidative enzyme), alcohol dehydrogenase III (mitochondrial enzyme). Work with isolated mitochondria shows that alcohol dehydrogenase III is the only form of alcohol dehydrogenase present in these organelles. Starch gel electrophoresis of alcohol dehydrogenase III reveals an active zone of slow migration which consists of five sub-bands. The relative activity of these five sub-bands varies with the conditions of growth. Mitochondrial alcohol dehydrogenase represents never more than 10% of the total cellular alcohol dehydrogenase. Information for its biosynthesis seems to be located in nucleic DNA. The mitochondrial enzyme shows a high affinity for alcohols with a double bond conjugated to the alcohol function. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Synthesis and degradation of early mRNA in lambda phage.? [/INST] Using two different Escherichia coli mutants defective in elongation factors EFG and EFTs required for peptide synthesis, lambda phage with or without a tof mutation was analysed for synthesis of early mRNA by DNA-RNA hybridization technique. (1) In CP78G carrying temperature-sensitive elongation factor G, shift-up to high temperature (41 degrees C) in the middle of phage infection did not affect early mRNA synthesis with lambdatof+ phage but did inhibit it with lambdatof- phage. (2) In HAK88 carrying temperature-sensitive elongation factor Ts, shift-up to 41 degrees C dropped total cellular RNA synthesis to below 10-20 percent of the control in the presence or absence of phage infection (stringent control). Under such a condition for suppressed protein synthesis, lambda early mRNA synthesis was completely blocked with both tof+ and tof- phage infection. Thus, stringent control seems to exert its effect on lambda early mRNA synthesis. (3) Addition of chloramphenicol, which is known to relax the stringent control of RNA synthesis, to the culture of phage-infected HAK88 at 41 degrees C resulted in full recovery of tof+-mRNA synthesis, but only in partial recovery to tof --mRNA synthesis. (4) Analysis of the stability of lambda mRNA indicated an exponential decay, and a halflife of tof --mRNA of 6 min when that of tof+-mRNA was 13 min at 37 degrees C. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Aminoacylation of Phaseolus vulgaris cytoplasmic, chloroplastic and mitochondrial tRNAsMet and of Escherichia coli tRNAsMet by homologous and heterologous enzymes.? [/INST] Met-tRNA synthetase from Paseolus vulgaris cytoplasm could be separated from its chloroplastic or mitochondrial counterpart by DEAE-cellulose chromatography, but the Met-tRNA synthetase from the two latter organelles could not be distinguished using DEAE-cellulose, hydroxyapatite or CM-Sephadex chromatography. As revealed by reverse-phase chromatography, bean cytoplasm contains 2 tRNAsMet; only one is charged by chloroplast, mitochondrial or Escherichia coli Met-tRNA synthetase. Mitochondria contain, in addition to the 2 cytoplasmic tRNAsMet, 3 mitochondria-spedific tRNAsMet; 2 can be formylated by the mitochondrial or the E. coli transformylase; all 3 are charged by mitochondrial, chloroplastic or E, coli Met-tRNA synthetase; none is charged by the cytoplasmic enzyme. Chloroplasts contain, in addition to the 2 cytoplasmic tRNAsMet, 3 chloroplast-specific tRNAsMet, different from the mitochondrial tRNAsMet; one is formylatable by the chloroplastic or the E. coli transformylase; all 3 are charged by chloroplastic, mitochondrial or E. coli Met-tRNA synthetase; only one is charged by the cytoplasmic enzyme. Of the 3 E. coli tRNAsMet, only the formylatable species can be charged by bean cytoplasmic, chloroplastic or mitochondrial Met-tRNA synthetase. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Substrate specificity of Salmonella typhimurium RNAase III and the nature of products formed.? [/INST] RNAase III, an endonuclease specific for double-stranded substrates, has been obtained in a highly purified form from extracts of Salmonella typhimurium. Poly (I-C) and a mixture of poly(A) and poly(U) (1 : 1), the latter in presence of 5 mM Mg2+, act as excellent substrates. Poly(I-C) is only partially hydrolysed by RNAase III and the product or products are acted upon by both RNAase I and RNAase II indicating that the products may be oligonucleotides. This conclusion is supported by two-dimensional chromatography on DEAE paper. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [Study of the degradation reaction of paranitrosodimethylaniline by a C-nitrosoreductase of yeast].? [/INST] We have purified, by a three step procedure, a yeast C-nitrosoreductase and studied its action on p-nitroso-N,N-dimethylaniline. Microcalorimetric measurements performed on the microcalorimeter LKB "batch", have been given the number of protons exchanged during the reaction : four protons are involved. Two are given by NADH and the others are supplied by the buffer. We could observe two steps in the catalytic mechanism. The enthalpy change of the first one is greater than that of the second. Spectrophotometric and polarographic experiments corroborate this results : two enzymatic steps could be demonstrated. The reduction of p-nitroso-N,N-dimethylaniline is characterized by a peak with a half wave potential at -0,31 V (in M Tris-HCl, pH 8,30). While the amplitude of this one decreases, a second wave appears at -1,03 V. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [Analysis of a small quatity of polypeptides by two-dimensional electrophoresis: application to characterization of proteins].? [/INST] A new two-dimensional electrophoresis is described. The first electrophoresis is performed in a 10 p. cent gel (1 X 110 mm) in the presence of 7 M urea; the migration in the second dimension proceeds on a 20 p. cent polyacrylamide sheet (160 X 110 X 1 mm) in the presence of sodium dodecyl sulphate. This system resolves most of the polypeptides obtained by treating a very small amount (about 100 mug) of proteins with cyanogene bromide. Macromolecules can thus be quickly and easily characterized. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [Quaternary structure of Escherichia coli polynucleotide phosphorylase: chemical characterization of form A].? [/INST] We had previously shown the existence of two classes of polynucleotide phosphorylases : Form A which is made of alpha chains and carries the catalytic sites ; and form B which is constituted of alpha chains and of beta chains. We performed some chemical analyses of form A (N-terminal sequence, amino acid composition, peptide mapping) which suggest that the alpha chains are all identical and moreover that they have no relationship with the beta chains. The latter do not therefore derive from a partial proteolytic degradation of the alpha chains and can therefore be considered as true subunits of the enzyme. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effects of changes in growth rate on the levels of several aminoacyl-tRNA synthetases in yeast.? [/INST] When the growth rate of yeast cells is decreased (for instance by transferring the cells from a rich medium to a poor one, or when the cells enter the stationary phase, or when growth is inhibited by cycloheximide, or when valine is removed from the medium supporting growth of a valine-requiring mutant, or when a thermosensitive mutant is shifted to the non-permissive temperature) there is a decrease in the levels of the four aminoacyl-tRNA synthetases tested. Conversely, an increase in the growth rate is accompanied by an increase in the levels of the four enzymes. But when the growth rate is slowed down by decreasing the temperature of the medium, no effect on the levels of the aminoacyl-tRNA synthetases is observed. These results are consistent with the concept of "metabolic regulation" proposed by Parker and neidhardt. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Nuclear power for the artificial heart.? [/INST] Studies showed that a totally implantable nuclear-powered artificial heart is practicable, and consequently a prototype system development program was initiated in July 1973. Basic testing of the prototype should be completed in 1977, with extensive studies to qualify the device for clinical use running at least into the early 1980s. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Cellulase and protein production from mixed cultures of Trichoderma viride and a yeast.? [/INST] Fermentations with mixed cultures of the cellulolytic fungus Trichoderma viride and the yeast Saccharomyces cerevisiae or Candida utilis were examined. The fermentations were carried out in an aerated 5 liter fermentor with NaOH treated barley straw as the cellulose source (2-4%). Yeast was inoculated 24-32 hr after the fungus and the growth of the two organisms was followed through the production of CO2 and cell protein. In comparison with fermentations with T. viride alone, the production time for maximum yields of cellulases and cell protein was reduced by several days, depending on the straw concentrations. The protein content of the growth product was 21-22% and the amino acid composition of the product resembled that of T. viride alone. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Potato avoidance during pregnancy in women with a previous infant with either anencephaly and/or spina bifida.? [/INST] This investigation is a direct attempt to test Renwick's (1972) hypothesis that 95% of anencephaly and spina bifida (ASB) is preventable by the avoidance of potatoes during pregnancy. Although the numbers involved in the study are small, the investigation fails to support the concept that short-term avoidance of potatoes before conception and throughout pregnancy in women who have had a previous ASB infant reduces the recurrence risk. In the potato-free group, of 23 pregnancies which went to term two infants had ASB (8-7%); whereas in the non-potato-free group, of 56 which went to term two infants had ASB (3-6%). The recurrence risk in both groups was about 5%. The incidence of ASB in the groups shows no significant difference (P = 0-58) and in the potato-free group was not reduced by 95% as postulated by Renwick. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Recent advances in acoustical microscopy.? [/INST] One cannot be involved in research in universities, government establishments and industry for 35 years without becoming aware of a number of misconceptions about pure science, applied science, engineering and technology in the mind of the public and also in the very places where research is carried out. There is confusion about the aims of research and development. There is uncertainty about the proper roles of universities, research establishments and industry. There is the question whether science is intrinsically good or not. The author illuminates some of these issues by relating milestones in the development of microscopy--optical as well as electron--and gives a snapshot picture of the recent work at Stanford University on the acoustic microscope as a felicitous instance of physics applied to the ever-present desire of mankind: to explore the unknown and to understand nature. Experiments with a mechanically scanning type of acoustic microscope have shown that a resolution limited only by diffraction can be attained and using a sonic frequency of 1-2 GHz, objects of less than 1 mum diameter can in principle be resolved. Various biological tissues have been explored and it appears that the acoustical images contain information substantially different from that obtained optically or electron-optically. Images have also been obtained using the harmonic radiation generated within the object and this mode of operation promises to open up yet another dimension of information. When, in due course, the full power, and the limitations, of the acoustic microscope are appreciated, its use may well lead to advances in science and technology comparable to those brought about by the introduction of the electron microscope. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The management of urinary fistulae following cadaveric renal transplantation.? [/INST] Vesicoureteric, ureteric and calyceal fistulae in cadaver transplants may be successfully treated by early exploration and nephrostomy splintage with silastic tubing for a period of not less than 6 weeks. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The microbial flora of the vagina and its relationship to bacteriuria in diabetic and non-diabetic women.? [/INST] The vaginal and urinary flora have been studied in 57 diabetic and 33 non-diabetic patients. In both populations, no correlation was found between urogenital symptoms and colonisation of the vagina. There was no greater prevalence of potentially pathogenic organisms in diabetic patients, even when control was poor. However, although not statistically significant, group B streptococci were isolated more frequently from poorly controlled diabetics. Bacteriuria was not significantly more common in diabetics. Gram-negative bacilli were found in the vagina significantly more often in bacteriuric patients; the prevalence of such organisms being four-fold greater after the menopause. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Antibiotic resistance and survival of E coli in the alimentary tract.? [/INST] Some antibiotics tend to select for R-factor-carrying Escherichia coli in the human gut, with complex long-term consequences. Some resistant strains disappear rapidly when treatment ends, while others persist for months in the absence of obvious antibiotic selection pressure, and the performance of individual resistant strains seems to depend more on the nature of the strain than on the plasmid carried. R plasmids are relatively rare in those E coli that colonize well in the gut and resistant bacteria therefore tend to disappear when treatment ends, but this situation could change dramatically if R plasmids became prevalent among those strains of E coli that colonize effectively. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The forgotten nodule: complications of sacral nodules in rheumatoid arthritis.? [/INST] Nodules commonly occur in rheumatoid arthritis and occasionally give rise to complications. The sacral nodule is easily missed and may ulcerate to produce extensive sacral sores which may lead to serious and even fatal complications in patients with rheumatoid arthritis. Seven cases are reported which illustrate some of these features. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Which elements are excited in electrical stimulation of mammalian central nervous system: a review.? [/INST] (1) There are data on the amount of current necessary to stimulate a myelinated fiber or cell body and/or its axon a given distance away from a monopolar electrode over the entire range of practical interest for intracranial stimulation. Data do not exist for other electrode configurations. (2) Currents from a monopolar cathode of more than 8 times threshold may block action potentials in axons. Therefore, only axons lying in a shell around the electrode are stimulated. Elements very close to the electrode may not be stimulated. Close to an electrode small diameter axons may be stimulated and larger ones may not be. (3) Most, and perhaps all, CNS myelinated fibers have chronaxies of 50-100 musec. When gray matter is stimulated, the chronaxie is often 200-700 musec. It is not clear what is being stimulated in this case. Current-duration relations should be determined for many more responses. (4) There are no current-distance or current-duration data for central finely myelinated or unmyelinated fibers. (5) It takes less cathodal current than anodal to stimulate a myelinated fiber passing by a monopolar electrode. When a monopolar electrode is near a cell body, on the opposite side from the axon, often the lowest threshold is anodal, but sometimes cathodal. Stimulation of a neuron near its cell body is not well understood, but in many cases the axon is probably stimulated. (6) Orientation of cell body and axons with respect to current flow is important. For an axon it is the component of the voltage gradient parallel to the fiber that is important. (7) The pia has a significant resistance and capacitance. Gray matter, white matter, and cerebrospinal fluid have different resistivities, which affect patterns of current flow. (8) More is known about stimulation of mammalian CNS than most workers are aware of. Much of what is unknown seems solvable with current methods. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Carboxyl-terminal sequences of procaryotic ribosomal proteins from Escherichia coli, Bacillus stearothermophilus, and Halobacterium cutirubrum.? [/INST] The carboxyl-terminal amino acid sequences of two ribosomal proteins, Escherichia coli L12 and E. coli S4, and the proteins believed to be their equivalents from Bacillus stearothermophilus and Halobacterium cutirubrum, were determined. These proteins are known to be required for peptide chain termination (L12) and in ribosome assembly (S4). The carboxyl-terminal sequences obtained suggest that the E. coli and B. stearothermophilus proteins have retained structural homology in this region, whereas the H. cutirubrum proteins have not. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Reconstitution of 48 S particles with subunit association activity from Escherichia coli 50 S ribosomal components.? [/INST] Previous studies have shown that 50 S ribosomal proteins bind sequentially to RNA's of the 50 S subunit via temperature-dependent steps (0 leads to 37 leads to 55 degrees C) to form 28, 32, (43) and 48 S particles (Chu, F.K., and Maeba, P.Y. (1973) Can. J. Biochem. 51, 129-139). When three equivalents of 50 S ribosomal proteins are used per equivalent of 23 S RNA, the yield of reconstituted 48 S particles is greatly increased. The addition of 10 mM spermidine increases the rate of reconstitution and abolishes the need for prior incubation at lower temperatures when 48 S particles are formed at 55 degrees C. In the presence of excess 50 S ribosomal proteins and 10 mM spermidine, 48 S particles formed at 50 degrees C are able to associate with 30 S subunits in a stoichiometric manner to form 70 S complexes. These 48 S particles compete effectively with 50 S subunits for 30 S subunits and have an association activity equal to that of 50 S subunits. As compared to the 34 proteins in 50 S subunits, 4 are either absent or present in marginal amounts, 11 in reduced amounts, and 19 in approximately normal amounts in the 48 S particles. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Nuclear demethylation and C-24 alkylation during ergosterol biosynthesis in Saccharomyces cerevisiae.? [/INST] The role of 4,4-dimethylzymosterol (3), 4,4-dimethylfecosterol (4) and 31-norlanosterol (5) in the biosynthesis of ergosterol in Saccharomyces cerevisiae has been investigated. The synthesis of 4 and 5 coupled with the availability of 3 facilitated a search for these sterols in commercial yeast sterol concentrates, fresh laboratory grown yeast and fresh brewery grown yeast. Sterol 4 was not detected in any of these mixtures whereas 5 was found in the first and last and 3 was present in all three sources investigated. Investigation of incorporation of [2-3H]lanosterol into 3, 4 and 5 revealed significant incorporation into 3 but neither 4 nor 5. This observation suggests the principle pathway for ergosterol biosynthesis initially involved 1 leads to 3 leads to 7. Incubation of a mixture of [2,4-3H]zymosterol and [26,27-14C]lanosterol with S. cerevisiae revealed that during the initial phases of aerobic growth the major route from 7 to ergosterol involves zymosterol (11) but as 11 accumulates 4 alpha-methyl-24-methylenezymosterol (8) assumes equal importance. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Inhibition of oxidative metabolism in Escherichia coli by d-camphor and restoration of oxidase activity by quinones.? [/INST] Oxidative metabolism in whole cells of Escherichia coli strain 82/r was inhibited by d-camphor when glucose, pyruvate, or succinate was used as substrate. Inhibition was not due to lower surface tension in d-camphor-treated cell suspensions nor was it a function of cell permeability. Succinic, lactic, and NADH-oxidase activities were inhibited in alumina powder cell-free extracts (80 mug of protein/ml) by d-camphor (1100 mug/ml). NADH: and succinic: DCPIP oxidoreductase enzymes were unaffected by d-camphor. Menadione (vitamin K3) restored succinic, lactic, and NADH-oxidase activities in d-camphor-inhibited cell-free extracts. Concentrations of menadione used to restore succinic and NADH oxidase activities were not stimulatory in non-camphor-treated extracts. Succinic oxidase activity in d-camphor-inhibited cell-free extracts was also restored by ubiquinone (Q6) but not by vitamin K1. These results are interpreted to indicate that d-camphor may affect quinone function in E. coli. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The influence of hydrostatic pressure upon biochemical activities of heterotrophic bacteria.? [/INST] Heterotrophic terrestrial and marine bacterial protein synthetic rates decrease by about 16% of the 1-atm rate for every 100 atm of pressure increment, within the pressure range of 1 to 500 atm. It is proposed that protein synthesis is nore severely inhibited by pressure than are other anabolic or catabolic reactions. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Physiological and psychological effects of alpha and EMG feedback training with college drug users: a pilot study.? [/INST] Twenty-four volunteer college students who were regular drug users were randomly allocated to three training groups of equal size: alpha feedback, EMG feedback and a joked control group. The subjects were unaware of which feedback condition they received and were asked to practise at home during a six-month follow-up period in order to achieve a relaxed state similar to that experienced during training. No group was successful in retaining gains made in their alpha levels during each session, but the EMG group significantly reduced their muscular activity during training and retained the improvement during follow-up. The alpha and joked groups did not greatly improve their EMG during training but at follow-up achieved the same levels as the EMG group. There was evidence to suggest that a reduction in drug use among light and medium users was maintained during follow-up. Significant and lasting improvements were made by each group in the duration and quality of their sleep and anxiety levels were reduced. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about D. Campbell Meyers, M.D., L.R.C.P., M.R.C.S. (Eng.) 1863-1927, pioneer of Canadian general hospital psychiatry.? [/INST] The paper describes the pioneering contributions of Dr. D. Campbell Meyers (1863--1927) to general hospital psychiatry during the first decade of this century at the Toronto General Hospital where, between 1906 - 1911, he operated the first public general hospital psychiatric unit in Canada. His conflict with Dr. C. K. Clarke who opposed his efforts is documented. To honour Meyers' contributions the Department of Psychiatry, Toronto General Hospital, has been named "The D. Campbell Meyers Memorial Department of Psychiatry". </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Studies in pericardial function. I. Cardiovascular effects of assisted ventilation, thoracotomy and pericardiectomy in the anesthetized dog.? [/INST] In anesthetized dogs, initially breathing spontaneously, the effects of intermittent positive pressure ventilation (IPPV), thoractomy and pericardiectomy on cardiac function, pericardial-ventricular relationships and cardiopulmonary volumes were evaluated. After IPPV stroke volume and work decreased. After thoracotomy there was no further change in cardiac output or work. Pericardiectomy superimposed at this point had no clear-cut effect. End-diastolic transmural pressures (ventricular minus pericardial) and cardiopulmonary volumes were not altered at any stage of the study. In the ventilated open-chest dog the effects of IPPV are greater than those of thoracotomy, and the extent of the effects is related to the level of IPPV. With moderate IPPV and adequate ventilation, the systemic hypotension, marked decreases in cardiac output and reduction of heart volumes reported by previous investigators can be avoided. The removal of the pericardium does not appear to have any deleterious effect in the normal dog. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Glucose dependent alterations of mitochondrial ultrastructure and enzyme content in mouse pancreatic islets maintained in tissue culture: a morphometrical and biochemical study.? [/INST] Isolated islets of Langerhans from mice were maintained in tissue culture for one week at either a high (28 mM) or a low (3.3 mM) extracellular glucose concentration. Electron microscopic morphometry by means of stereological methods revealed a much greater volume of mitochondria in islet cells cultured at low glucose than in those cultured at high glucose. The former islets also showed a higher activity of the mitochondrial marker enzyme, L-3-hydroxyacyl-CoA-dehyrogenase (E.C.1.1.1.35). These results indicate a true mitochondrial hypertrophy at the low glucose concentration. Although it is known from previous studies that the islet cell metabolism is diminished after low-glucose culture, the present observations of an increased mitochondrial volume probably do not reflect a degenerative process, but rather adaptive changes towards oxidation of energy yielding substrates other than glucose. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Pancreatic islet cytology of Ictaluridac (Teleostei).? [/INST] The endocrine pancreas of the bullhead catfish, Ictalurus nebulosus, and the channel catfish, I. punctatas was studied by light and electron microscopy. In addition to the usual A, B and D cells, a fourth endocrine cell type was consistently observed in the electron microscope. All endocrine cell types were innervated. The vesicles of most of the nerve endings were ultrastructurally different from typical adrenergic and cholinergic vesicles, strongly suggesting the possibility of a third autonomic neurotransmitter serving as a regulator of catfish islet secretion. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Time of fixation and the localization of Gomori-positive and neurophysin-containing structures in the rat hypothalamus.? [/INST] Rats were decapitated and the complete head stored at 4 degrees C. At various time intervals, up to a maximum of 14 days, the brains and pituitary glands were removed and fixed in formalin-picric acid. Neurosecretory material (NSM), as revealed with crotonaldehyde fuchsin, and neurophysin as demonstrated by means of immunoperoxidase histochemistry were localized in the hypothalamic magnocellular nuclei, median eminence and posterior pituitary gland. NSM and neurophysin were present in the paraventricular (PVN) and supra-optic (SON) nuceli up to periods of 14 days although the cellular morphology was disrupted after about 4 days. After 4 days there was an abundance of positive staining "droplets" in both the SON, PVN and along the nerve fibers of the supraoptico-neurohypophysial tract. Pituitary gland NSM and neurophysin were still present 14 days post mortem. The slab gradient polyacrylamide gel electrophoresis pattern of soluble proteins extracted from the posterior pituitary gland from the experimental and normal animals showed almost complete identity confirming the minimal action of proteolytic enzymes at 4 degrees C up to a period of 6 days. It is concluded that as long as the tissue is cooled, rapid fixation of hypothalamic tissue is not essential for the localization of NSM and neurophysin. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Oxytocinase-immunohistochemical demonstration in the immature and term human placenta.? [/INST] Oxytocinase (cystine aminopeptidase) was purified from human retroplacental serum by a combination of fractional precipitation, hydroxylapatite chromatography and gel exlusion chromatography on Sephadex G-200. The purified enzyme possessed a specific activity of 980 mIU/mg using L-cystine-di-p-nitroanilide as substrate. This represented a 3200 fold concentration from the starting material in an overall yield of 12%. Antibodies against oxytocinase were raised in rabbits and the gamma-globulins fraction labelled with fluorescein isothiocyanate prior to its use in the immunofluorescence histochemical localization of the enzyme in human placental tissue. Oxytocinase was confined to the syncytiotrophoblastic cells of normal term, and immature placentas as well as in placentas from patients suffering from severe toxaemia. Specific immunofluorescence was also present in the outer margins of the chorion and to a lesser extent in the amnion. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Types and distribution of lamellar bodies in first cleavage Xenopus embryos.? [/INST] Lamellar bodies in first cleavage Xenopus laevis embryos have been examined with the electron microscope. Based on the arrangement and relative thickness of the lamellae, three types of lamellar bodies have been identified. In the first type, a band of two to ten lamellae (spacing about 3.5 nm) was interwined at random. This type of lamellar body was seen closely associated with the concave or the forming face of the Golgi body and may have been derived from this organelle. The frequent association of these lamellar bodies with the growing cleavage furrow may suggest a transfer of materials from the Golgi body to the furrow through the lamellar bodies or their precursors. In the second type, typical myelin-like figures with a repeating distance of about 10 nm were located close to the furrow tip. In the third type, membrane whorls containing tetrads of lamellae (approximately 16 nm thickness) were seen associated with lipid droplets. If the lamellar bodies observed in this study were formed during fixation then the appearance of three different types after the same fixation procedure would indicate the presence of a similar number of pools of precursor materials which differ in their chemical composition and distribution in the embryo. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Histochemical and electron microscopy investigations on medullary bone.? [/INST] Folliculin administration to pigeons stimulates the development of medullary bone in marrow spaces of the femora and other long bones. It is a specialized osseus tissue not devoted to mechanical functions and which is rapidly reabsorbed before egg-shell formation. Medullary bone is formed and reabsorbed in the same way as other types of bone. Consequently, because of its very rapid rate of formation and resorption, it represents an ideal tissue for studying osteoblastic, osteoclastic and osteocytic activity, and the calcification process. Medullary bone is deeply stained by PAS, Alcian blue and colloidal iron and is metachromatic after toluidine blue staining. This shows that its interfibrially ground substance contains relatively high amounts of glycoproteins and acid proteoglycans. Calcification initially occurs in maxtrix vesicles (or calcifying globules) which are very numerous between the collagen fibrils of the osteoid tissue, and successively spreads into the surrounding interfibrillar matrix. Here, the crystals are closely related to thin, filament-like organic structures which seem to be components of ground substance proteoglycans. These findings confirm that in medullary bone, as in other types of calcifying tissue, the inorganic substances is initially laid down within calcifying globules and is successively closely related to organic, non-collagenous, filamentous organic structures (crystal ghosts) which probably represent a framework for calcium salt deposition. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Studies of mouse mitochondrial DNA in Escherichia coli: structure and function of the eucaryotic-procaryotic chimeric plasmids.? [/INST] The mouse mitochondrial DNA genome has been cloned in Escherichia coli by linking it to the pSC101 plasmid replicon at cohesive-ended cleavage sites generated by Eco Rl restriction endonuclease. The four possible configurations of chimeric molecules that contain the nucleotide sequences of mitochondrial DNA in their native relationship were distinguished by Hind III restriction endonuclease digestion and electron microscopic heteroduplex analysis. Chimeric molecules utilize the pSC101 replication origin and do not maintain the "D-loop" region or the low frequency of ribonucleotides found in native mitochondrial DNA. Hybridization of the RNA synthesized in E. coli minicells carrying the four types of chimeras indicates that transcription occurs predominately on the light strand of the mitochondrial DNA in all cases. This result implies that initiation of RNA synthesis occurs within the mitochondrial DNA segment. Although specific polypeptide synthetis is directed by the mitochondrial DNA segment of each of the chimeras in E. coli minicells, the molecular weight distribution of the polypeptides synthesized consists primarily of low molecular weight species and thus differs from that observed in mitochondria in mouse L cells. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Observer agreement in evaluating coronary angiograms.? [/INST] The reliability of interpretation of coronary arteriography as a diagnostic tool was investigated in a sub-study of the VA Cooperative Study of Surgical Treatment for Coronary Arterial Occlusive Disease. Twenty-two physicians with varying levels of experience read 13 cine angiograms -- blind -- on two different occasions. Analysis of inter- and intraobserver variability showed that angiographic items about which observers were most inconsistent from one reading to the other had the largest interobserver disagreement as well. They were the distal portions of the left anterior descending and left circumflex arteries. Among the items on which there was most consistent agreement -- namely, the right main coronary artery and presence of ventricular aneurysm -- there was most often agreement between observers as well. When individual readers were evaluated, some observers were far more consistent in their own readings of all the angiographic items than others. This intraobserver agreement in turn correlated fairly well with how often they agreed with the other observers and with how much experience they reported having in reading coronary cineangiograms. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Nasal hyposensitization and hay fever.? [/INST] A clinical trial of pre-seasonal hyposensitization with intra-nasal grass pollen extract was carried out in forty-two patients. Results were assessed subjectively, by clinical examination during the pollen season, and by measurements of nasal air flow. Useful relief of symptoms was considered to have occurred in fifteen out of twenty-one patients who had pre-seasonal treatment with pollen extract and in five out of twenty-one patients who had similar treatment with carbol saline as a placebo. Of twelve patients who were symptom free in the pollen season ten had nasal hyposensitization. It is concluded that this simple and safe method of treatment gives results comparable with those of pre-seasonal injections. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Intranasal betamethasone valerate in the treatment of seasonal rhinitis.? [/INST] Betamethasone valerate aerosol given in doses of 100 mug into each nostril twice daily was compared with a placebo in a double-blind, cross-over trial involving thirty patients with seasonal rhinitis. Patients recorded symptoms of eye irritation and watering, sneezing, rhinorrhoea, and nasal blockage, on a diary card. Analysis of the symptom scores showed that nasal symptoms were significantly better on betamethasone valerate than on placebo (P less than 0.01) and that nasal blockage in particular was improved (P less than 0.001). The patients' preference was significantly in favour of the active compound (p less than 0.02) and no side-effects were noted. It is concluded that betamethasone valerate offers a safe and effective form of treatment for seasonal rhinitis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effect of beclomethasone dipropionate aerosol on allergen induced nasal stenosis.? [/INST] Nasal resistance to air flow has been used to evaluate the effect of beclomethasone dipropionate aerosol on allergen induced nasal stenosis. Sixteen patients with allergic rhinitis due to pollen were investigated in a randomized double-blind cross-over study with beclomethasone dipropionate aerosol and placebo aerosol. Only patients reacting to challenge were chosen. The study was carried out in the pollen-free season. After 1 week on either active or placebo aerosol a basic resistance value was determined followed by allergen challenge. Nasal resistance was determined 15 min and 7 hr after challenge. The aerosols were changed and after another week the procedure was repeated. There was significant preference (P less than 0.01) for beclomethasone dipropionate aerosol. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Application of pepsin-digested horse antibodies for quantitative immunoelectrophoresis.? [/INST] The majority of the precipitating antibodies in hyperimmune horse serum belong to the beta globulins, as demonstrated by reversed immunoelectrophoresis. As these antibodies migrate in agarose gel during electrophoresis in conventional pH = 8.6-8.9 buffers, horse antiserum cannot be used satisfactorily for quantitative immunoelectrophoresis. On pepsin digestion of horse antiserum F(ab)' 2 fragments are generated which migrate with the gamma globulins. This cleaved product works well in quantitative immunoelectrophoretic techniques. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Monitoring of patients with head injuries.? [/INST] A practical protocol for evaluating and monitoring head injured patients has been presented. It has been stressed that monitoring is an ongoing process which begins with the initial evaluation and continues throughout the patient's hospital stay. The level of monitoring and thus the parameters to be monitored are determined on an individualized basis according to the patient's clinical status and his level of stupor and coma. It has been suggested that for mild head injuries, adequate monitoring includes periodic evaluation of the neurological status and vital signs; but the more severely injured patients require extensive and frequent monitoring of a large number of clinical and physiological parameters. Among the many parameters, the continuous monitoring of ICP and the respiratory system are perhaps the most useful indicators of the patient's condition. Several methods for continuous ICP monitoring which are readily adaptable to most neurosurgical practices have been discussed. These include the intraventricular catheter, subarachnoid screw, and the closed Rickham reservoir connected to a ventricular catheter. In our institution, the Rickham reservoir has been used to monitor ICP and at the time of this report, satisfactory ICP recordings have been obtained in 27 of 30 head injury patients. Although this method requires a small surgical procedure, we believe that the decreased incidence of infection, the rapid access to ventricular fluid, and its potential for long term monitoring justify its use. Suggestions for monitoring other physiological parameters have also been presented. Particular emphasis has been placed on the management of infants and children with head injuries. The clinical entity of chronic subdural hematoma in infants and children has been used to illustrate the value of ICP monitoring as a guide to further treatment. Finally, we have briefly discussed the place of computers in day to day patient care, research, and monitoring. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Volume and pressure in the craniospinal axis.? [/INST] Raised intracranial pressure is common in neurosurgical practice, but the clinical effects are variable. The factors which initiate intracranial hypertension are now fairly well established; the extent of the increase of intracranial pressure produced by any combination of these factors is a function of the volume-pressure status of the patient at that particular time and may be expressed in terms of brain clastance. The effects of raised intracranial pressure on the function of the brain are mediated through both changes in cerebral blood flow and brain shift or herniation. Understanding of these principles helps in selection of effective therapy for raised intracranial pressure. Ideal clinical management of raised intracranial pressure should be directed toward the identification of those situations in which intracranial pressure may become increased and should attempt to prevent intracranial hypertension before it actually occurs. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Increased arachidonate in lipids after administration to man: effects on prostaglandin biosynthesis.? [/INST] Ethyl arachidonate was administered orally to 4 healthy male volunteers in a dose of 6 gm daily for a 2 to 3 wk period after 10-day control period. The increased intake of this precursor of the dienoic prostaglandins resulted in significant increases in the relative and absolute amount of arachidonate in plasma triglycerides, phospholipids, and cholesteryl esters. Similar changes in lipid composition were noted in platelets. The excretion of 7alpha-hydroxy-5,11-diketotetranoprostane-1,16-dioic acid, the major urinary metabolite of E prostaglandins in man, was increased by an average of 47% in 3 of the 4 volunteers. Platelet reactivity was assessed by determining the threshold concentration of adenosine diphosphate (ADP) necessary to induce secondary, irreversible aggregation of platelet-rich plasma. This threshold concentration dropped significantly in all volunteers (10% to 60% of control values). It is concluded that the biosynthesis and function of prostaglandins can be augmented in man by oral administration of an esterified precursor fatty acid. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Nefopam and morphine in man.? [/INST] A new analgesic, nefopam, is chemically distinct and pharmacologically unrelated to any presently known analgesic. A comparison was made of morphine and nefopam in 74 patients who required parenteral analgesia for moderate to severe postoperative and somatic pain, using a single administration, 2-dose level, double-blind design. A significant dose-response curve was obtained with nefopam and with morphine, and there was no significant deviation from parallelism. The time-effect curves for the 2 drugs were similar. The estimated relative potency of nefopam to morphine indicates that 20 mg of nefopam HCl is the approximate analgesic equal of 12 mg of morphine SO4. There were no adverse effects with nefopam and one adverse reaction to morphine. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Butorphanol and pentazocine in patients with severe postoperative pain.? [/INST] Either butorphanol tartrate (1, 2, or 4 mg) or pentazocine (30 or 60 mg) was given intramuscularly (5 dose groups) to 262 patients, who were scheduled for major operations, if they had severe pain after full awakening in the recovery room, postoperatively under double-blind conditions. There were at least 50 patients in each of the five dosage groups. Pain intensity and relief were scored numerically for each treated patient at 1/2 1, 2, 3 and 4 hr, while under direct surveillance, and the patients were seen again for follow-ups during the first 24 hr postoperatively. Appreciable pain relief developed within 30 min at all dose levels, with a peak analgesic effect apparent at about 1 hr. Satisfactory relief persisted for 4 hr in the majority of patients in each group. With the lowest dose of butorphanol tartrate (1 mg), which gave good pain relief for only 2 to 4 hr, approximately 60% of the patients had to be remedicated within 4 hr. Vital signs were not appreciably affected, but the patients who received the high dose of analgesics (butorphanol tartrate 4 mg or pentazocine lactate 60 mg) were often quite drowsy. The incidence of other side effects was negligible. The relative potency assay showed that butorphanol was approximately 20 times as potent as pentazocine for up to 4 hr. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Oral benzquinamide in the treatment of nausea and vomiting.? [/INST] The clinical antiemetic effect of bezquinamide by oral route at a dosage of 100 mg 3 times daily was evaluated by a controlled double-blind method in 183 studies of patients treated with 5-fluorouracil. The incidence of nausea and vomiting in benzquinamide-treated patients was equal to that in placebo-treated patients and significantly higher than that in patients treated with prochlorperazine, 10 mg 3 times daily. Sedation was the only significant side effect observed, and this occurred at essentially equal rates in benzquinamide- and prochlorperazine-treated patients. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A comparison of fenfluramine and amphetamine in man.? [/INST] dl-Fenfluramine hydrochloride (60, 120, 240 mg), d-amphetamine sulfate (20, 40 mg), and placebo were compared in 8 postaddict volunteers, each dose given orally in random sequence at weekly intervals using a double-blind crossover design. Fenfluramine had little effect on blood pressure and temperature, but caused a marked dilation of pupils, whereas amphetamine was a potent vasopressor and a weak mydriatic. While fenfluramine produced euphoria in some subjects, its overall effects were unpleasant, sedative, and qualitatively different from amphetamine. Three subjects given 240 mg of fenfluramine experienced brief but vivid hallucinogenic episodes characterized by olfactory, visual, and somatic hallucinations, abrupt polar changes in mood, time distortion, fleeting paranoia, and sexual ideation. These observations indicate that fenfluramine is a hallucinogenic agent with a pharmacologic profile in man that is not amphetamine-like. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Duration of hydralazine action in hypertension.? [/INST] The effect on blood pressure of giving hydralazine orally, 300 mg per day divided into 2, 3, and 4 doses, was studied in 4 hypertensive patients. There was no significant difference in average mean arterial pressure for the 3 regimens. Fluctuations of mean arterial pressure with time were not significantly different for the regimens as indicated by coefficient of variation. The mean coefficient of variation for the 2 days prior to initiation of hydralazine dosing was 4.0% +/- 0.3 (SEM) and for the 3 dosing regimens ranged from 4.1% to 4.8%. Heart rate was used as an index of vasodilator-induced increase in sympathetic tone and therefore as a measure of possible side effects. Fluctuations in heart rate were small and were not associated with symptoms. After discontinuation of hydralazine, the time for blood pressure to return halfway between initial placebo value and end treatment value varied from 30 to 140 hr. A tracer dose of hydralazine 14C. HCl was administered intravenously to the patients. The urinary excretion of 14C showed a multiexponential pattern of elimination with a previously undescribed prolonged terminal phase. Under the conditions of the present study, a daily dose of 300 mg of hydralazine was as effective and free of side effects given in 2 as in 4 divided doses. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Occurrence, transport, and storage of octopamine in human thrombocytes.? [/INST] 3H-octopamine was found to be accumulated in human platelets, achieving a maximum concentration gradient of 30:1. Its accumulation was partially inhibited by reserpine, imipramine, serotonin, ouabain, dinitrophenol, and iodoacetate. When octopamine was added to platelet preparations, it led to a decrease of both endogenous and 14C-serotonin. To determine whether octopamine accumulates in human platelets in vivo, preparations from 6 patients receiving monoamine oxidase inhibitors and 17 control subjects were assayed enzymatically for octopamine. Octopamine was detectable in all of the drug-treated patients, averaging 0.45 +/- 0.06 ng/mg protein, while only 4 of the 17 control subjects had detectable (greater than 0.05 ng/mg protein) platelet octopamine. Although much lower than platelet serotonin levels, these octopamine levels are in the range of those reported for platelet norepinephrine and epinephrine. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Clinical trials of drugs from the viewpoint of the academic investigator (a satire).? [/INST] Dr. Lasagna was unable to attend the workshop in person, and therefore delivered his remarks by videotape, in the assumed role of the newest "Secretary of Human Experimentation" at the Department of Health, Education, and Welfare addressing a public television audience. There is no difficulty in sensing the serious truths underlying the satire in his address. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Panel 2: phase II investigations.? [/INST] At the end of Phase II, a decision must be made as to whether or not the drug should be developed as a therapeutic agent. Such a decision may be based on many criteria in addition to the scientific data derived from the Phase II study. At this point, expert judgment is needed. One should like to assume that if the decision is made to proceed with the increasingly expensive and laborious process of further development, the drug will, barring some completely unforeseen misadventure, ultimately find its way into clinical therapeutics. Phase II studies, therefore, are the most crucial stage in the course of drug development. Planning of these studies requires great care and investigators of the highest caliber should be used for their conduct. The escalating costs of new drug development are resulting in an undesirable imbalance of efforts in the direction of studies characterized more by easily defined end points than by therapeutic needs. Industry, academia, and the FDA must all be concerned with facilitationg studies in areas of most-needed therapeutic advances. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Clinical evaluation of two daily doses of naproxen and indomethacin: result of a double-blind crossover trail.? [/INST] A double-blind crossover clinical trial is reported on the effects of naproxen in two doses, 500 mg. and 750 mg. daily, and 100 mg. indomethacin daily in 23 patients with classical rheumatoid arthritis, each drug being given for 1 week. The results show that there was little to choose between the drugs and that there was clinical equivalence between the two doses of naproxen. Radioactive pertechnetate (99mTc) joint uptakes were depressed by both naproxen and indomethacin, indicating anti-inflammatory effect. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A double-blind trial of methocarbamol versus placebo in painful muscle spasm.? [/INST] A double-blind trial of methocarbamol versus placebo was carried out in 59 matched pairs of patients suffering from painful muscle spasm. Methocarbamol (1500 mg. q.d.s.) was found to be effective in approximately 60% of patients compared with 30% of patients receiving placebo (p less than 0.01). Side-effects were of almost equal incidence in the two groups. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The possibility of latent centromeres and a proposed nomenclature system for total chromosome and whole arm translocations.? [/INST] Translocations involving entire chromosomes or whole chromosome arms may not necessarily require deletion of a centromere. Conceivably, in the process of centromeric or telomeric fusion or of fusion of a centromere with a telomere, centromeric inactivation may occur, thus preserving both centromeres--one functional, the other latent--in the resultant translocation chromosome. If such latent centromeres exist and, in addition, are capable of being reactivated, it would explain how additional functional centromeres are acquired in the reverse process of chromosomal fission or fragmentation. A system of nomenclature is proposed for identifying the origin and nature of these chromosomal rearrangements. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Potent combinations of beta-lactam antibiotics using the beta-lactamase inhibition principle.? [/INST] Several penicillins known to be stable to enterobacterial beta-lactamases were tested in combination with beta-lactamase-sensitive penicillins and cephalosporins in a turbidimetric system. Nafcillin was found to be the best beta-lactamase inhibitor amongst agents presently available commercially, but the related, new semi-synthetic penicillin BRL 1437 (2-isopropoxy-1-naphthylpenicillin) was consistently found to be superior. Using 103 ampicillin-resistant coliform bacilli and antibiotic levels achievable in urine, cephalothin or cephaloridine alone achieved long-term suppression of growth (greater than 20 h) of 16 and 13% of strains, respectively, while the additional presence of BRL 1437 suppressed growth for longer than 20 h of 81% of the remaining strains. Even where 'success' was not achieved according to these stringent criteria, regrowth was significantly delayed by the presence of BRL 1437. Suppression of growth for longer than 20 h by BRL 1437 plus cephalothin was achieved with all of the 46 Escherichia coli strains tested. Antibiotic combinations were also studied in an in vitro model which stimulates the hydrokinetic features of the urinary bladder. Suppression of the growth of two highly resistant E. coli strains was achieved in this system, for therapeutically acceptable periods of time, with combinations of cephalothin or cephaloridine with BRL 1437, but not nafcillin. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Adjuvant immunotherapy for malignant brain tumors in infants and children.? [/INST] Immune deficiency of immunocompetent cells or of humoral factors are essential causes of tumor growth. The authors have investigated the transfer of immunocompetent cells - allogeneic bone marrow cell transfusion and white blood cell intracranial infusion - for the treatment of 11 malignant gliomas in infants and children as an adjuvant to surgery, radiation and/or chemotherapy. Ten cases, from 3 months to 11 years, received bone marrow cell transfusion. Two medulloblastomas and 3 pontine gliomas are dead. Five cases are alive and well 37-65 months following surgery. Among these two posterior fossa neoplasms, a medulloblastoma and a glioblastoma have survived 46 and 65 months, respectively. One cerebral glioblastoma received allogeneic white blood cells infused locally into the tumor bed: it recurred 1 year following surgery, chemotherapy, and immunotherapy. Cytolysis of the tumor cells by sensitized lymphoid cells were demonstrated in this case. The role of immunotherapy should be limited at the present time to adjuvant therapy until its effect on tumor growth is statistically confirmed. The results so far are promising, and improvement of the immunological approach in treating malignant brain tumors is under way. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Manifestations and management of Arnold-Chiari malformation in patients with myelomeningocele.? [/INST] As a result of the authors' experience they advocate posterior fossa decompression in patients with myelomeningocele at the first sign of compression of bratn stem or the cervical cord or both. If decompression is not undertaken at once the impaired gag and cough reflexes place the child at risk. He may develop pneumonia. If decompression is delayed too long full neurological recovery will not occur. The removal of bone and the opening of dura must be carried down to the bottom of the tonsillar tip, sometimes as low as C7. The most dramatic improvement occurs in infants whose symptoms are life threatening. Less dramatic but just as real is the improvement in older children. Although investigations such as myelography and ventriculography will show the malformation, they are not essential. The associated visible malformations and the clinical condition are the most reliable means of making the diagnosis. Delaying the decompression risks the life of the infant and threatens the quality of life for the older child. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [Contaminated infusions as cause of nosocomial Serratia marcescens septicaemia in children (author's transl)].? [/INST] At the University Children's Clinic at Munich 25 cases of Serratia marescens septicaemia (mainly bacteriocin types 18 and 44) occurred within one year, predominantly in newborns and infants. Almost all of the children were seriously ill from an underlying illness or had been operated on. Two thirds had received antibiotics before the septicaemia occurred but they were ineffective. Of a total of nine antibiotics tested against 51 Serratia marcescens strains, nalidixic acid (99% sensitivity) and amikacin (100%) proved the most effective. Main source of the septicaemia were contaminated infusions, from which in as many as 35% of cases microorganisms, usually Serratia marcescens, had been isolated. Intensive hygienic measures at once terminated this "sepsis wave". </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Stimulation of LH release and ovulation in the rat by cutaneous application of luteinizing hormone-releasing hormone (LH-RH) in dimethyl sulfoxide (DMSO).? [/INST] The efficacy of cutaneously applied luteinizing hormone releasing hormone (LH-RH) in stimulating LH release in the chronically ovariectomized, estrogen/progesterone-blocked rat and ovulation in the chlorpromazine-blocked, proestrous rat was investigated. Following the cutaneous application of 25 or 100 mug of LH-RH in 100% dimethyl sulfoxide (DMSO), serum LH rose to a peak at 1 hr, then declined toward basal levels in the ensuing 3 to 4 hr. LH-RH applied cutaneously in either 100% DMSO or 0.9% NaCl was also capable of inducing ovulation in the chlorpromazine-blocked, proestrous rat; however, LH-RH in 0.9% NaCl did not yield a linear log-dose-response relationship, therefore a valid ED50 potency ratio for DMSO/0.9% NaCl could not be estimated. Nonetheless, 0.9% NaCl was a considerably less effective cutaneous vehicle than DMSO. Cutaneous application of LH-RH in DMSO in doses of 100, 50, 25, 10, 5, 2.5 and 1 mug induced ovulation in 100%, 100%, 90%, 73%, 30%, 10% and 0% of the rats, respectively. When the percent ovulation response was transformed to probits and plotted against the logarithm of the LH-RH dose an approximately linear log dose-response was obtained; the same relationship also held true for ovulation induction following sc LH-RH administration. In turn, the ED50's of these two parallel dose-response curves yielded a potency ratio estimate (sc/cutaneous) of 0.025, suggesting that 2.5% of the cutaneously applied LH-RH dose was absorbed through the skin in a biologically active form. These data indicate that DMSO privdes a convenient cutaneous vehicle for the administration of LH-RH. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Anti-insulin serum coupled to Sepharose 4B as a tool for the investigation of insulin biosynthesis in the B-cells of obese hyperglycemic mice.? [/INST] The biosynthetic activity of the B-cells of obese hyperglycemic mice (obob) was measured by the incorporation of [3H]leucine into proteins in collagenase-isolated pancreatic islets. To quantitate the incorporation into proinsulin and insulin, an immune binding method was used. For this purpose, anti-insulin serum was coupled to cyanogen bromide-activated SepharoseR 4B. This turned out to be a specific and versatile technique for the measurement of newly synthesized proinsulin and insulin in the B-cells. The B-cells of obob mice appear to be well adapted to a high rate of hormone biosynthesis, since at 16.7 mM glucose 44% of [3H]leucine incorporated into TCA-precipitable proteins was bound to the insulin antibodies coupled to Sepharose 4B. The insulin biosynthetic rate was stimulated 9 times at 16.7 mM glucose, during a 3-h incubation, compared with the basal insulin biosynthesis rate. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Blockage of estrogen-induced release of luteinizing hormone by reserpine and potentiation of synthetic gonadotropin-releasing hormone-induced release of luteinizing hormone by estrogen in the ovariectomized ewe.? [/INST] These experiments tested the effects of reserpine on estrogen-induced LH release and the effects of estrogen on gonadotropin-releasing hormone-induced LH release in ovariectomized ewes. Injection of 50, 200, or 500 mug of estradiol benzoate (EB) into progesterone-treated ewes, or of 50 mug of EB into non-treated ewes induced a large surge in serum LH levels approximately 15 h later. Injection of 5 mg/ewe of reserpine 6 h prior to the EB, blocked the LH surge. Reserpine reduced, but did not block the release of LH induced by injection of 20 mug or 40 mug of synthetic gonadotropin-releasing hormone (GnRH). Injection of graded doses (5, 10, or 20 mug) of GnRH into progesterone-treated ewes that had been treated with reserpine, induced increases in serum LH levels that were proportional to the logarithm of the dose. In the final series of experiments both progesterone-treated and non-treated ewes were injected with reserpine and then with either EB or oil. Fifteen hours after receiving EB or oil they were injected with either GnRH or the diluent. GnRH elevated serum LH levels significantly higher in ewes given EB than in those given oil. LH levels in ewes given oil and diluent were not elevated. These data suggest that reserpine blocked EB-induced LH release by an action on the central nervous system and that EB acted directly on the anterior pituitary to increase the response to GnRH. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Modulation of the enzymic activity of chicken pepsin by the covalent modification of its single -- SH group.? [/INST] The single cysteinyl residue of chicken pepsin was modified with a wide spectrum of reagents to produce mixed disulfides or alkylated derivatives. All these derivatives showed enhanced catalytic activity towards the synthetic peptide Z-Ala-Ala-Phe-OPrP, where OPrP is the 3-(4-pyridyl)-propyl-1-oxy group. The overall catalytic constant kcat/Km for these derivatives was 4 -- 25-fold larger than that of the native enzyme. The activity of the enzyme towards denatured hemoglobin was slightly decreased (10--45%) by these modifications. When the mixed disulfide derivatives were treated with excess mercaptan, the sulfhydryl group was regenerated and activity reverted to that of the native enzyme. The --SH group of chicken pepsin reacted preferentially with reagents containing an aromatic group. The reaction was found to depend on the ionization of a single group, presumably the --SH itself, with a pKa = 7.5. The rate of reaction of the fully deprotonated species with various disulfides was 100--1000-fold smaller than that of the --SH group of glutathione. It is suggested that the groups attached covalently to the sulfhydryl also interact with other amino acid side chains in the protein thereby affecting the active center of chicken pepsin. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Initiation specificity of the poly(cytidylic acid)-dependent Qbeta replicase activity.? [/INST] The initiation specificity of RNA synthesis catalysed by the poly(C)-dependent Qbeta replicase activity was investigated with various synthetic ribopolymers as template. It was found that the initiation efficiency of a series of oligo(C) with various chain lengths is proportional to the template size. Synthetic riboheteropolymers containing cytidylic acid were accepted as templates only if they contained at their 3' end a cytidylic acid sequence of more than 5 nucleotides. Such an oligocytidylate sequence served also as an initiator sequence for copying the non-cytidylic-acid-containing part of the heterotemplate. RNA synthesis always began with the incorporation of GTP, even if the 3'-terminating nucleotide of the template was not cytidylic acid. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Solution conformation of virginiamycins (staphylomycins).? [/INST] The 1H (at 300 MHz) and 13C nuclear magnetic resonance spectra of virginiamycins S and S4 and vernamycin Balpha have been unravelled and analyzed. Together with model building and theoretical considerations, this allows the detailed description of their solution conformations. The depside bond can rotate and gives to the backbone some conformational mobility. The orientation of the depsicarbonyl bond depends on the surrounding. Apparent discrepancies between the different methods that are applicable for the disclosure of the nature of peptide H-bonding, have found a rational explanation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about On the dissociation and association of Escherichia coli ribosomes.? [/INST] The dissociation and association behaviour of 70-S ribosomes of Escherichia coli has been studied. It has been shown that the dissociation-association reaction can be both a real dynamic equilibrium and a non-equilibrium reaction, dependent upon the ionic conditions of the solvent. At relatively high ionic strength (I = 0.15 M or more) the dissociation-association reaction is an equilibrium reaction, whereas at lower ionic strength (I = 0.1 M or less) there is no dynamic equilibrium between 70-S ribosomes and its subunits. In the latter case a hysteresis in the dissociation-association reaction is observed. Whether there is a dynamic equilibrium or not can be demonstrated by a single centrifugation experiment, using the analytical ultracentrifuge. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Ultrastructural organization and biochemical characterization of chromatin - RNA - protein complexes isolated from mammalian cell nuclei.? [/INST] Extranucleolar elements were isolated from mammalian cell nuclei and characterized by correlative biochemical-ultrastructural studies. These complex structures were shown to retain a supra-particle arrangement closely resembling the organization in situ of definite nuclear areas. In particular the morphological RNA - protein species, namely perichromatin fibrils and granules, were detected in association with characteristic regions of chromatin. By autoradiographic experiments, we were able to show that perichromatin fibrils represent the morphological state of newly formed heterogeneous nuclear RNA (hnRNA). Chromatin - RNA - protein complexes were further fractionated by means of a treatment dissociating the chromatin component. A minor part of DNA, possibly involved in the biosynthesis and the processing of hnRNA, remains linked to the resulting RNA - protein network. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Phage Qbeta replicase: cell-free synthesis of the phage-specific subunit and its assembly with host subunits to form active enzyme.? [/INST] Cell-free translation of Qbeta RNA and subsequent partial purification of the enzyme resulted in replicase activity. From 0.5 to 1.5% of all R chains synthesised were found in the 7-S replicase complex. The presence in the 7-S complex of the host subunits of authentic replicase, i (= S1) and EF-Ts, was shown by the effect of antisera directed against ribosomal protein S1 and EF-Ts, respectively. Furthermore, the presence of EF-Ts was demonstrated by thermal denaturation of in vitro replicase made by a cell extract from an Escherichia coli mutant with a thermolabile EF-Ts. In vitro replicase did not assemble spontaneously during protein synthesis but was formed upon subsequent purification. Assembly could be induced by ammonium sulphate precipitation (60% saturation) alone. It is concluded that the functional phage-coded subunit synthesised in vitro recognises i and the EF-Tu - EF-Ts complex among a mixture of host proteins. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The use of primed synthesis by DNA polymerase I to study an intercistronic sequence of phiX-174 DNA.? [/INST] A decadeoxynucleotide complementary to ten nucleotides in the major ribosome-protected fragment of phiX-174 plus-strand DNA has been chemically synthesized and used as a primer for DNA polymerase I on phiX-174 plus-strand DNA as template. The sequence of the first 40 nucleotides incorporated onto the decadeoxynucleotide has been determined. This sequence extends further the sequence of the intercistronic region preceding gene G and shows the presence of another termination codon. The sequence was determined by using manganese as the activating cation for DNA polymerase I which allows ribonucleotides to be incorporated as well as deoxyribonucleotides. The ribo-substituted product was then cleaved specifically at the ribonucleotide residues to generate a series of overlapping ribo-terminated fragments whose sequences were sufficient to determine the complete sequence of the first 40 nucleotides. No evidence for misincorporation by DNA polymerase I in the presence of manganese was detected. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The importance of Escherichia coli ribosomal proteins L1, L11 and L16 for the association of ribosomal subunits and the formation of the 70-S initiation complex.? [/INST] 50-S subunits were washed with LiCl solutions of different concentrations. After washing with 1 M LiCl solution the particles lost their ability to attach either to 30-S subunits or to the AUG - 30-S subunit - fMet-tRNAfMet complex or to a poly(U) - 30-S subunit - Phe-tRNAPhe complex. Those proteins which were removed by LiCl were fractionated on a Sephadex G-100 column. Of the fractionated proteins only the combinations L1 and L11 or L1 and L16 were essential for the association of 50-S 1.0 cores (particles prepared by washing 50-S subunits in 1.0 M LiCl) with 30-S subunits. These three proteins were also required for the formation of a stable complex between 50-S 1.0 cores, mRNA, 30-S subunits and aminoacyl-tRNA. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Interaction between arginase and L-ornithine carbamoyltransferase in Saccharomyces cerevisiae. The regulatory sites of arginase.? [/INST] The inhibition of ornithine carbamoyltransferase by arginase in Saccharomyces cerevisiae, which is under the control or arginine and ornithine, involves a regulatory site for arginine on the arginase distinct from its catalytic site. This regulatory site is responsible for the reinforcement effect of arginine on the inhibition of ornithine carbamoyltransferase by arginase. The binding site of ornithine carbamoyltransferase on arginase is also shown by our analysis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Envelope-bound N-acetylmuramyl-L-alanine amidase of Escherichia coli K 12. Purification and properties of the enzyme.? [/INST] N-Acetylmuramyl-L-alanine amidase activity was detected in Escherichia coli K 12 by usine N-acetylmuramyl-L-alanyl-gamma-D-glutamyl-(L)-meso-[3H]diaminopimelic acid as a radioactive substrate. This activity cleaves the amide bond between the residues of N-acetylmuramyl acid and L-alanine. It was readily obtained in a soluble form either by mechanical disruption of the cells or by spheroplast formation. In the latter case the release of most of the activity into the sucrose medium seems to indicate that it is either periplasmic or associated with the outer membrane of the envelope of E. coli K 12. The enzyme was purified to near homogeneity. A molecular weight of 39 000 was determined by gel filtration and confirmed by polyacrylamide gel electrophoresis. Further characterisation of this N-acetylmuramyl-L-alanine amidase activity was carried out by investigating several of its properties. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The isolation of two different lipopolysaccharide fractions from various Proteus mirabilis strains.? [/INST] Four distinct Proteus mirabilis strains were extracted by the phenol/water procedure. After ultracentrifugation of the dialyzed water phase, the pelleted lipopolysaccharide was purified and analyzed. The sugar composition of this lipopolysaccharide fraction I was similar for all four strains, containing only small amounts of strain-specific constituents. A second lipopolysaccharide fraction was isolated from the supernatant above (termed L1 fraction) after removal of nucleic acids. DEAE-cellulose chromatography indicated that this material is not a polysaccharide but rather a water-soluble lipopolysaccharide containing strain-specific constituents such as uronic acids, amino acids, amino sugars, neutral sugars, ethanolamine and phosphate, depending on the strain from which lipopolysaccharide II was isolated. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Identification of ribitol phosphate as a constituent of the lipopolysaccharide from Proteus mirabilis, Strain D52.? [/INST] A polyol was released from the lipopolysaccharide of Proteus mirabilis, strain D52, during alkaline hydrolysis and its phosphate ester was isolated after acid hydrolysis. This polyol has been identified as ribitol by comparison of the free polyol, its phosphate ester and its anhydro derivative formed after acid treatment with authentic xylitol, D- and L-arabitol, ribitol and their corresponding derivatives on paper and gas-liquid chromatography. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Function of the duct-ligated canine pancreatic allograft.? [/INST] Heterotopic transplantation of a duct-ligated canine pancreas was performed in 20 previously pancreatectomized, non-related recipient dogs. A technical procedure was elaborated for this grafting. It was found that early, fatal postoperative bleeding in the recipient could be avoided when the interval between pancreatectomy and transplantation was reduced from 7 to 2-4 days. The early endocrine function was studied in 15 surviving animals by determination of blood glucose and serum insulin during fasting and during glucose load. 24 h after transplantation the blood glucose values were normal and 4-8 days after transplantation the glucose tolerance was within normal limits. The serum insulin was on a supranormal level, also during glucose load. The early endocrine capacity of the transplanted duct-ligated pancreas after transplantation was found to be satisfactory, restoring the blood glucose in the pancreatectomized recipients to normal levels. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The psychiatric aspects of cardiac intensive therapy: a review.? [/INST] The post cardiotomy state is typically delirious and although organic factors are important it is multi-determined. Cerebral ischaemia has been implicated in the development of psychological disorder after resuscitation but longer term neurotic disorders also occur. Affective disturbances, particularly depression, are associated with the coronary care experience. The following conditions are directly related to an increased incidence of psychological disorder: age, loss of sleep, sensory deprivation, stressful experiences, pre-operative morbidity (both physical and mental), the severity of both surgical trauma and the post-operative medical state. For both the staff who administer intensive therapy and the patient who receives it there are unique psychological hazards, the management of which depends largely on mutual understanding and support. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Behaviour of the duct-ligated canine pancreas during hypothermic albumin perfusion.? [/INST] The behaviour of eight duct-ligated canine pancreata was studied during 23 hours of continuous, hypothermic perfusion, with an albumin electrolyte solution. The organs developed a considerable oedema during perfusion. This did not seem to influence on the vascular resistance of the organs. A continuous insulin release, a moderate increase in LDH concentration and only small changes in the electrolyte concentrations were observed in the perfusate, indicating only a moderate degree of cellular damage. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Twenty-four-hour preservation of the duct-ligated canine pancreatic allograft.? [/INST] Twenty previously pancreatectomized dogs received a duct-ligated pancreatic allograft; 16 of the grafts were preserved for 24 h, 9 with continuous hypothermic albumin perfusion, 7 with simple hypothermic storage; 4 glands were transplanted immediately and served as controls. The outcome of preservation was assessed by studying the early endocrine function of the glands. Excluding five early failures due to bleeding, all grafts showed endocrine activity after transplantation and the glucose values were on a normal level. An initial hyperglucemia caused by pancreatectomy disappeared within 24h. In the two groups with 24h preservation, no differences in graft function were found. In the control group, there was a hypoglucemic tendency the first days after transplantation and a prolonged hyperinsulinemia during glucose load. It could be concluded that duct-ligated, isolated canine pancreas well tolerated 24h of preservation both by continuous hypothermic albumin perfusion and by simple hypothermic storage in an extracellular type of fluid. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Plasma catecholamines and blood substrate concentrations: studies in insulin induced hypoglycaemia and after adrenaline infusions.? [/INST] Plasma adrenaline-blood glucose interrelationships in insulin-induced hypoglycaemia in man have been studied using a sensitive double-isotope derivative method for adrenaline estimation. Plasma adrenaline reached a peak of 1.24 ng/ml at 45 minutes after insulin while blood glucose reached a nadir of 22 mg/100 ml at 30 minutes. There was a strong correlation both between the rise in adrenaline and the degree of hypoglycaemia and between the rise in adrenaline and the post-hypoglycaemic rise in glucose. Plasma noradrenaline rose from 0.29 to 0.59 ng/ml, the rise correlating with the rise in adrenaline. Changes in pulse rate preceded and were unrelated to changes in plasma catecholamines. Fuel mobilisation in response to adrenaline infusion (6 mug/min. for 20 min.) in normoglycaemic man was also studied. Plasma adrenaline concentration rose from a mean of 0.02 ng/ml to 0.71 ng/ml while plasma noradrenaline concentration was unchanged. Blood glucose rose from 71 to 98 mg/100 ml while plasma insulin decreased from 11 to 8 muU/ml. Blood lactate rose by 0.85 mM while pyruvate concentration remained unchanged. Blood glycerol concentration rose twofold and ketone body concentration threefold but there was little change in the concentrations of the glucogenic amino acids, alanine, glutamate and glutamine. Both the 3-hydroxybutyrate/acetoacetate ratio and the lactate/pyruvate ratio rose implying a more reduced intracellular state due presumably to increased hepatic fatty acid oxidation. It is concluded that adrenaline enhances the recycling of lactate and spares glucose through the mobilitsation of lipids but that amino acids are little affected. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Insulin metabolism, insulin sensitivity and hormonal responses to insulin infusion in patients taking oral contraceptive steroids.? [/INST] The metabolism of unlabelled human monocomponent insulin was studied in a group of six patients being treated with combined oestrogen-progestogen oral contraceptives (OC) and compared with a group of ten normal subjects. The parameters of insulin metabolism were determined by a priming dose-continuous infusion technique which enabled measurements of metabolic clearance rate (MCR) of insulin to be made at four separate steady state hormone concentrations spanning the physiological range. In normal subjects MCR was greatest at low insulin concentrations, falling from 24.7 ml/kg/min. at 16 muU/ml to 11.4 ml/kg/min. at a mean concentration of 280 muU/ml. In the OC group, MCR averaged 20.5 ml/kg/min. and did not change with increasing plasma insulin concentration. The plasma half-disappearance time (T 1/2) was longer than normal in the OC group (5.6 vs. 4.4 min., p less than 0.05) despite a higher MCR. The prolonged T 1/2 indicated that the apparent distribution space was increased in those on OC (166.6 vs. 82.7 mg/kg., p less than 0.0025). The results are interpreted as indicating increased capillary permeability to insulin and increased peripheral degradation. The fact that MCR did not fall in the OC group with increasing plasma insulin concentrations whereas it did in normal subjects, suggested that OC leads to the loss of saturable component of insulin degradation that is present in normal subjects. Insulin sensitivity (as judged by induced hypoglycaemia) was reduced in the OC group while growth hormone responses were within the normal range. Plasma cortisol was increased in those taking OC but the response to insulin induced hyperglycaemia was less marked than normal. The results indicate a significant alteration in insulin metabolism in these subjects, which may contribute to the impairment of carbohydrate tolerance seen in some women taking combined OC. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A stereotaxic headholder for visual neurophysiology.? [/INST] A stereotaxic headholder is presented that offers the following advantages: 1. It is especially suitable for visual neurophysiology, because the eye and surrounding orbit are not affected by bars or clamps. 2. It is easy to handle, because the ear bars are mounted on movable slides above the main frame. 3. It is versatile and can be used without additional adapters for different species of animals. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Synaptosomal uptake and levels of serotonin in rat brain areas after p-chloroamphetamine or B-9 lesions.? [/INST] In contrast to the pronounced fall in 5HT levels and synaptosomal uptake caused by p-chloroamphetamine, bilateral lesions of the B-9 cell group caused minimal regional changes, except for 35% decreases in the metathalamus-thalamus. We conclude therefore that the prolonged biochemical effects of p-chloroamphetamine are not due to a selective cytotoxic action on B-9 cells; and that a lateral 5HT pathway, possibly from the B-9 cell group, projects to the metathalamus-thalamus. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Immunologic studies of male infertility.? [/INST] Infertile men with azo- or oligospermia of unknown cause were investigated for evidence of testicular autoimmunity. Testicular germinal cell antibodies were found in 14% of the patients, compared with 5% of normal men, and 21% had spermatozoal antibodies, compared with 5% of the normal subjects. One-third had positive macrophage inhibitory factor tests, compared with 5% of normal subjects. However, of autoantibodies against thyroid, stomach, and nuclear material, only the prevalence of thyroid cytoplasmic antibodies was significantly greater than in normal subjects; serum IgG, IgM, and IgA levels were normal in all cases tested. Furthermore, there was no excess of lymphoid tissue on biopsy and no evidence of antibody deposition in the testicular tissue. The evidence for autoimmunity is less impressive than that for leprous orchitis, which has been proposed as a model for testicular organ-specific autoimmunity. Nevertheless, it is possible that certain germinal cell or spermatozoal antibodies may be directed against factors necessary for orderly spermatogenesis. If so, they may play a role in some cases of maturation arrest and shedding defects. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Inhibitory activity of four analogs of luteinizing hormone-releasing hormone in vivo.? [/INST] Four analogs of luteinizing hormone-releasing hormone (LH-RH), [des-His2,D-Ala6]-LH-RH, [des-His2,D-Ala6, des-Gly-NH2(10)1-LH-RH ethylamide, [des-His2,D-Leu6]-LH-RH, and [D-Phe2,D-Leu6]-LH-RH, at 300-fold molar ratios (analog/LH-RH) led to an almost complete inhibition of LH response to LH-RH in anesthetized 4-day cycling rats on the afternoon of proestrus. At a 75-fold molar ratio, [des-His2,D-Ala6]-LH-RH still inhibited the LH-RH-induced LH release by 50%. The ethylamide substitution at the COOH terminus of [des-His2,D-Ala6]-LH-RH did not significantly improve the inhibitory activity of the molecule. </s>