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<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Recognition and significance of maternogenic fetal acidosis during intensive monitoring of labor.? [/INST] FHR monitoring and microanalysis of fetal blood are mutually complementary procedures, and optimal knowledge of the fetal state is achieved by making use of both, the former for the preliminary screening of all cases at risk and the latter for the purpose of deciding on obstetric management where pathological changes are evident in the FHR. The major difficulty in obtaining a precise value for the fetal acid-base balance lies in the occurence of "falsely abnormal" cases, i.e. cases in which the fetal pH falls during labor but the clinical condition at birth is good (APGAR greater than or equal to 7). In our own series the incidence of such cases among fetuses at risk was 11.2% (Tab. I). In the majority of these cases the fetal acidosis is thought to be a result of increased metabolic acidosis in the mother (maternogenic fetal metabolic acidosis). The importance of the maternogenic fetal acidosis during labor lies in the fact that unless it is recognised, rapid extraction of the fetus will appear necessary on clinical grounds, although it is in fact unnecessary, since this form of acidosis has no adverse effect on the fetus. Various parameters have been proposed for the differential diagnosis of the maternogenic fetal acidosis. These include the feto-maternal difference in base deficit (F/M deltaBD), the materno-fetal differences in pHqu 40 (M/F deltapHqu 40) the materno-fetal difference actual pH (M/F actual deltapH), and the materno-fetal difference in base deficit of the extra-cellular fluid (M/F deltaBDHb5). A critical analysis of these parameters has been carried out on the results of microtests performed during a 5 year period (1968-1972) at the First Clinic of Obstetrics and Gynecology of Milan University. The cases comprised 59 regarded as normal (normal course of pregnancy, spontaneous commencement of labor at term, clear amniotic fluid, regular FHR, spontaneous birth, APGAR at 90 sec between 8 and 10, weight at birth greater than 2500 g), and 335 considered to be at risk (maternal disease, presence of meconium stained amniotic fluid and/or abnormal changes in FHR). In all of these cases the FHR was recorded by cardiotokography, and the tracings were interpreted according to HON. Microsamples of blood were taken from both mother and fetus during labor and the following determinations were carried out: actual pH, pHqu 40, Hb concentration, hemoglobin oxygen saturation, base deficit Hb5 (BDHb5). The maternofetal differences were then calculated. The same determinations were carried out on samples of maternal blood and of arterial and venous cord blood taken immediately after delivery. The clinical condition of the infant was evaluated by the APGAR score at 90 seconds after birth. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Solubilization and stabilization of the cytotoxic agent coralyne.? [/INST] Kinetic studies were carried out on the ring opening of the quaternary nitrogen cation, coralynium ion (I), to yield 6'-acetylpapaverine (III), on the cyclization of III to yield I, and on a photochemical reaction undergone by I in aqueous solutions exposed to visible light. From the results, it was concluded that: (a) I and III are in facile equilibrium in aqueous solution but appreciable amounts of III do not exist in dilute solutions with pH values below 10: (b) the photochemical reaction of I in water (presumably a photohydration) can be reversed by lyophilization, by heatiing, and by increasing the pH of solutions to values greater than 12; (c) the photochemical reaction of I can be inhibited by protecting the aqueous solutions from visible light, and the rate in the presence of light can be reduced by increasing the concentration of I in the solution; and (d) although the chloride and sulfoacetate salts of I react identically and have similar solubilities in water, it is possible to prepare more concentrated and, hence, more stable solutions of the sulfoacetate salt by including sodium hydroxide in the solvent. The solubility of coralyne chloride remains about the same in dilute sodium hydroxide as in water. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Solvolysis of a substituted imidazoline, mazindol.? [/INST] Hydrolysis of mazindol to form 2-(2-aminoethyl)-3-(p-chlorophenyl)-3-hydroxyphthalimidine was followed spectro-photometrically in aqueous solutions at temperatures between 37 and 70degree, pH values up to 7.6, and an ionic strength of 0.2. The effects of acetate, formate, and phosphate buffers as well as ionic strength on the observed rate constants were investigated. An interesting nonlinear dependency of the kobs with buffer concentration was noted. The velocity constants declined with increasing hydrogen-ion concentration; the log k-pH profile and rate law are given along with other relevant data. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Complexation in formulation of parenteral solutions: solubilization of the cytotoxic agent hexamethylmelamine by complexation with gentisic acid species.? [/INST] The apparent solubility of hexamethylmelamine in aqueous solutions suitable for intravenous use was increased by complexation with gentisic acid. Studies were carried out in the pH 0-8 range. Unprotonated hexamethylmelamine did not form complexes with the gentisate ion, while the hexamethylmelammonium ion appeared to form several different complexes with both the gentidate ion and gentisic acid. Two different solid complexes were isolated and characterized. The solubility increases observed at pH 3.5-5.0 are described by mathematical relationships involving the stability constants of some postulated complex species. From these results, sultable formulations for use as parenteral solutions are proposed. The increase in the apparent aqueous solubility of hexamethylmelamine in such formulations may range from five- to 90-fold, depending upon the pH and total gentisateion concentrations. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Inhibitory effect of dioctyl sodium sulfosuccinate on trypsin activity.? [/INST] The inhibitory effect of dioctyl sodium sulfosuccinate on the proteolytic activity of trypsin was investigate over the pH 6-8 range. The antitryptic activity was determined using two different substrates: casein and N,alpha-benzoyl-DL-arginine-p-nitroanilide hydrochloride. The mechanistic studies revealed the substrate-inhibitor interaction to be the overall major mechanism of inhibition. This interaction was shown to involve substrate depletion, probably involving some primary sites of the natural substrate casein. Some inhibition was also shown to be due to an interaction between the enzyme and the inhibitior molecules. The interactions of the inhibitor with the enzyme and the substrate were irreversible. The possible therapeutic significance of the inhibitory effect of the surfactant is discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about In vitro adsorption of diphenoxylate hydrochloride on activated charcoal and its relationship to pharmacological effects of drug in vivo. I.? [/INST] The adsorption of diphenoxylate hydrochloride, a potent antidiarrheal agent, on activated charcoal powder was studied in vitro. Langmuir adsorption isotherms were established at pH 4 and 7, and the maximum adsorption capacity of charcoal for this drug was estimated using these values. Activated charcoal modified the bioavailability of diphenoxylate hydrochloride in vivo. The antipropulsive action of diphenoxylate in the mouse was strongly inhibited in the presence of activated charcoal. A comparative evaluation of charcoal and chromium oxide used as inert, nonabsorbable markers revealed that chromium oxide may be the marker of choic in GI transit studies in laboratory animals since it does not influence the bioavailability of diphenoxylate hydrochloride. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Binding of bile acids to cholestyramine at gastric pH conditions.? [/INST] The binding of bile salts to cholestyramine was studied under varying conditions of pH and added electrolyte. The taurine-conjugated bile salts were strongly absorbed by the anion-exchange resin at low pH and in the presence of chloride anions. Glycocholic acid binding was very weak at low pH but increased strongly with increasing pH. The presence of chloride ions strongly decreased the amount of glycocholate bound by the anion-exchange resin. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Characteristics of gastric inhibition by acidification of oxyntic gland area.? [/INST] 1. Gastric acid responses to the test meals were measured in the Heidenhain pouch, gastric and pancreatic fistula dogs, using the intragastric titration method, and monitoring the rate at which a solution of 1-0 N-NaOH had to be added to maintain the pH of the gastric content constant at pre-selected values ranging from 5-0 to 1-0. In this way the pH profile of the gastric acid and pepsin responses to a liver extract meal kept in the Heidenhain pouch or gastric fistula as well as to exogenous stimuli such as histamine, pentagastrin or Urecholine could be determined. 2. A liver extract meal adjusted to pH 5-0 produced a potent and pressure-related stimulation of acid secretion from the Heidenhain pouch without any change in secretion from the main stomach and pancreas or in the serum concentration of immuno-assayable gastrin. 3. Graded decrease of the liver extract meal pH to below 5-0 resulted in the pH-dependent inhibition of gastric acid output, which at pH 1-0 was only about 30% of the value attained at pH 5-0. Acid secretion from the Heidenhain pouch induced by exogenous stimuli such as histamine, pentagastrin or Urecholine also showed gradual decrease when the pH of the pouch content was decreased in sequential order from 5-0 to 1-0. This pH-dependent inhibition was accompanied by an increase in pepsin secretion. 4. The pH-dependent inhibition of the Heidenhain pouch response to the liver extract meal was not altered by topical application of a local anaesthetic and atropine or by the intravenous infusion of large doses of atropine, secretin or metiamide, which were shown to cause a marked inhibition of the main stomach response to the liver meal. 5. The results indicate that there is a local and gastrin-independent inhibition mechanism of gastric acid secretion activated by an acidified meal making contact with the oxyntic gland area. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The influence of pH on equilibrium effects of tetrodotoxin on myelinated nerve fibres of Rana esculenta.? [/INST] 1. The experiments were done on single nodes of Ranvier of Rana esculenta. The effects of tetrodotoxin and H ions were determined either by the reduction of the maximum rate of rise, VA, of action potentials evoked with threshold stimuli or in the voltage clamp by the decrease of the peak Na permeability, PNa. 2. With the tetrodotoxin sample used throughout the investigation the equilibrium dissociation constant, KT, of the toxin-receptor reaction at neutral pH was determined to be 2-8 nM. Between 1-55 and 15-5 nM tetrodotoxin the normalized value, A, of VA, was found to be related to the normalized toxin concentration cT = [TTX]/2-8 nM by the empirical equation log [(1-A)/A] = 1-22 log cT-0-573. 3. On increasing the pH (up to 8-8) the effect of tetrodotoxin diminished as revealed by an increase in A. The apparent reduction of cT (as calculated from A) suggests that the toxin is active only in its cationic forms. 4. Weakly acid tetrodotoxin solutions (7-3 less than pH less than or equal to 5-5) reduced A to a lesser degree than did neutral toxin solutions in spite of the inherent depressing effect of acid pH on A (A = 0-5 at about pH 5-5). In more acid toxin solutions A decreased again and at pH 4-6 it was about equal to the value in toxin-free solution. 5. When, after equilibrium in an acid toxin solution, the perfusate was suddenly changed to neutral Ringer solution A jumped to a higher value A' as measured 1 sec after the switch. Since the blocking effect of hydrogen ions subsided within a fraction of a second while the time constant of the toxin washout is of the order of 1 min, A' reflects the number of Na channels blocked by tetrodotoxin at acid pH. 6. In acid toxin-free solution the peak PNa as obtained in voltage clamp experiments was reduced by a voltage-dependent factor (cH + 1)-1 with CH = [H+]/KH(E) and KH(E) = 2-04 muM exp (0-34 EF/RT). Adding tetrodotoxin resulted in another reduction by a constant factor p'T. 7. Experiments employing various combinations of toxin concentration (3-1-93 nM) and pH values (7-3-5-2) confirm the decreased toxin effect at low pH. Moreover, p'T was smaller (the additional toxin effect larger) when the membrane had been kept depolarized and thus cH reduced during equilibration. This suggests that tetrodotoxin cations and H ions compete for the same blocking site. A quantitative fit, however, requires additional assumptions. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The influence of pH on the rate of tetrodotoxin action on myelinated nerve fibres.? [/INST] 1. The experiments were done on single myelinated nerve fibres of Rana esculenta. The rates of toxin effect were studied either by measuring the maximum rate of rise, VA, of repetitively evoked action potentials or by measuring Na currents during periodic impulses in the voltage clamp. 2. VA measurements showed that in alkaline solutions (pH up to 8-8) the offset rate was unchanged while the onset was slowed in quantitative agreement with an assumed decrease in the active cationic form of tetrodotoxin. 3. Both VA measurements and those in the voltage clamp revealed a decrease in T'off, the offset time constant and in increase in the onset time constant, T'on, as the pH was lowered. 4. For tetrodotoxin concentrations, [TTX], up to 400 nM and pH values down to 5-3 the simple relation T'on/T'off = p'R held, where p'T is the constant factor by which the Na permeability was reduced at equilibrium with a given [TTX]. 5. The agreement between kinetic and equilibrium results was also valid when, at constant [TTX] and pH. p'T was modified by the holding potential during equilibration. 6. No unequivocal explanation of the results can be given but some of their features resemble acid catalysis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The formation of synapses in amphibian striated muscle during development.? [/INST] 1. A study has been made of the formation of synapses in developing reinnervated and cross-reinnervated amphibian twitch muscles which receive either a focal (iliofibularis) or a distributed (sartorius) innervation from 'en plaque' nerve terminals using histological, ultrastructural and electrophysiological techniques. 2. During the development of the tadpole through metamorphosis to the adult frog, the sartorius myofibres increased in length at about twice the rate of the iliofibularis myofibres, due to a fast rate of growth at their insertions on to the pelvic tendon. 3. The short iliofibularis and sartorius myofibres of young tadpoles (800 mum long) possessed only a single synapse and the iliofibularis myofibres did not receive any further innervation during development. However the sartorius myofibres received further transient innervation on the new muscle laid down during development at the fast growing pelvic insertion, until the distance between the original synapse formed on the myofibres and the synapse at the pelvic end of the muscle was about 12 mm. 4. During development synapses possessed either skewed, multimodal, or unimodal m.e.p.p. amplitude-frequency distributions; the intervals between m.e.p.p.s. were not distributed randomly according to a Poisson process, as m.e.p.p.s. of similar amplitudes tended to be separated by very short intervals; the unit-size e.p.p. had a similar amplitude-frequency distribution as the m.e.p.p.s. if these had a unimodal distribution. 5. Reinnervation or cross-reinnervation of the sartorius and the iliofibularis muscles in adults or at a late stage of development simply reconstituted the normal focal and distributed innervation patterns of the muscles, as found in the control muscles of the contralateral and unoperated legs. 6. These observations on synapse formation in amphibia are consistent with the hypothesis that during development the axon making the initial synaptic contact on the muscle cells induces a property over a length of muscle membrane adjacent to this site which makes it refractory to synapse formation; thus during reinnervation or cross-reinnervation of adult muscles this refractory property constrains synapse formation to these sites. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Comparative studies of Trypanosoma vespertilionis Battaglia and Trypanosoma dionisii Bettencourt & França.? [/INST] In diphasic blood agar media Trypanosoma vespertilionis developed spheroid clusters as compared to rather long, sausage-shaped (sometimes branched) clusters formed by Trypanosoma dionisii. The former species attained a greater population density (approximately 6 X 10(7) organisms/ml) than the latter (approximately 2 X 10(7) organisms/ml). Greater numbers of epimastigotes, some in active binary divisions, were observed during the logarithmic phase of growth, and morphologic changes occurred during cultivation which correlated with increased acidity and a depletion of glucose. Maximum numbers of trypomastigote forms were found during the stationary and early death phases. Most of the forms observed after 20 days were sphaeromastigotes. Glucose concentrations decreased to 0 M in T. vespertilionis and to 4.4 X 10(-5) M in T. dionisii cultures during the stationary and death phases. By the 12th day of incubation cultures of T. vespertilionis were more acid (pH 5.5) than those of T. dionisii vespertilionis and T. dionisii contained common and specific antigens. At least 2-3 common antigens were detected in extracts reacted against heterologous antisera. Specific antigens were observed as nonidentical lines formed by extracts reacted against homologous and heterologous antisera and with antisera absorbed with heterologous antigens. At least 2 specific antigens were evident in extracts of T. vespertilionis and 1 in extracts of T. dionisii. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about N-Isopropyl derivatives of dopamine and 5,6-dihydroxy-2-aminotetralin.? [/INST] Secondary and tertiary amino homologs of the title compounds have been prepared, bearing an N-isopropyl group. In peripheral evaluation, certain members of the series exhibited beta-adrenergic agonist effects of lower activity than isoproterenol. N-Methyl-N-isopropyl-5,6-dihydroxytetralin exhibited marked properties consistent with its being an alpha agonist, and it is concluded that introduction of considerable bulk about the nitrogen of a catecholamine does not a priori destroy alpha-agonist effects. The compounds qualitatively paralleled the effects of dopamine in assays based upon direct intrastriatal administration in rats, although they were less potent than dopamine. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Phospholipases. III. Effects of ionic surfactants on the phospholipase-catalyzed hydrolysis of unsonicated egg lecithin liposomes.? [/INST] Apparent values of Km and Vmax have been measured for catalysis of hydrolysis of unsonicated egg lecithin liposomes, activated through addition of 0.4 M n-hexanol, by phospholipases A2 from bee and snake venoms and by phospholipase C from Clostridium welchii as a function of the concentration of three surfactants: hexadecylamine, hexadecyltrimethylammonium bromide, and dihexadecyl phosphate. For all three enzymes, values of Km and Vmax show little or no dependence on the concentration of these ionic surfactants, demonstrating that the liposomal surface charge is not a crucial factor in determining susceptibility to phospholipase-catalyzed hydrolysis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Negative potential level in the outer layer of the toad skin.? [/INST] The isolated skin of the toad Bufo marinus ictericus when impaled from the outer surface by glass microelectrodes filled with 3 M KCl shows a voltage profile which is a continuous function of the depth of impalement. The superficial intraepithelial potential difference measured with reference to the external solution (PDi) is negative with NaCl-Ringer's solution on both sides of the skin, displaying a minimum of -26.7+/-3.6 mV at 6+/-2 mum. Null value is obtained at 19+/-3 mum, with positive values for deeper impalements. Indications of cell impalements (abrupt voltage and resistance jumps) were frequently observed at sites deeper than 25 mum from the outer surface. Measurements of the electrical resistance between the microelectrode and the external solution, made with single- and double-barreled microelectrodes, showed great discrepancies, which may be attributed to distinct pathways of different resistances in the stratum corneum. PDi measured at a depth of 5 mum was a logarithmic function of Na2SO4 or K2SO4 concentration in the external solution, increasing in negativity with a reduction in concentration. Substitution of Na by K in the external solution had only minor effects on PDi. Acidification of the external solution from pH 9 is accompanied by a reduction in the negative value of PDi. At pH 3 PDi was positive. PDi was interpreted as a diffusion potential at the tip of the microelectrode due to KCl diffusion from the electrode into the matrix of the stratum corneum. Differences in K and Cl mobilities, responsible for the origin of PDi, were attributed to fixed charges in the matrix of the stratum corneum, with density and polarity determined by their degree of proponation, controlled by the hydrogen ion concentration of the external solution. Skin potential, short-circuit current and their relationship to PDI were discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The avian erythrocyte: a study of fixation for electron microscopy.? [/INST] The quality of ultrastructural preservation of the avian erythrocyte achieved using various fixation techniques is evaluated. Different combinations of initial fixatives, buffers and post-fixation procedures were tested as well as variations in fixative osmolarity, pH and temperature. Of the commonly used initial fixatives (glutaraldehyde, acrolein and formaldehyde), 2% glutaraldehyde, alone in a slightly hypertonic buffer containing divalent ions, produced optimum erythrocyte preservation. The osmolarity was balanced using a non-electrolyte such as a sucrose. The addition of 12% hexylene glycol to the buffer solutions also improves erythrocyte preservation, as evidenced by the increased stability of the marginal microtubules, microfilaments and proteinaceous material. The use of Spurr low-viscosity epoxy resin enables the cells to be collected using low gravitational centrifugation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Hemoglobin solution and the oxyhemoglobin dissociation curve.? [/INST] 1) A study was carried out to determine the oxyhemoglobin dissociation curve of stroma-free hemoglobin solution and factors which influence it, (pH; 2,3 DPG). 2) To simulate acute volume replacement, dilution experiments, in vitro, were performed employing both hemoglobin solution and Ringer's lactate in whole blood. 3) It was determined that stroma-free hemoglobin solution has a left-shifted oxyhemoglobin dissociation curve which responds to pH change but not to the addition of 2,3 DPG. 4) The dilutional effect of hemoglobin solution when mixed with whole blood in volumes up to 50% was to left-shift the oxyhemoglobin curve, unlike the effect of Ringer's lactate (no change). 5) This may have importance in the hemodynamic compensatory response to acute normovolemic anemia. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of antihistamine-antiserotonin and ganglionic blocking agents upon increased capillary permeability following burn trauma.? [/INST] Tiny (0.2% TBS), partial thickness, non-contact radiant heat burns in guinea pigs resulted, within 3 hours, in significant edema formation and protein leakage at the site of the injury. Areas of skin distant to the burn also showed an increase in water content but no protein leakage. Pretreatment of the animals with either chlorisondamine hydrochloride or a mixture of methysergide and chlorpheniramine significantly decreased postburn edema formation and protein leakage. Liquid emulsion autoradiography revealed that leakage of protein occurs primarily in the areas of skin adjacent to the panniculus carnosus. The studies suggest that: the increase in vascular permeability that occurs as a consequence of burn injuries is humorally mediated; albumin leakage is limited to the injured tissues; and histamine, serotonin, and presumably catecholamines play significant roles in the development of this phenomenon. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Bacteriophage T4 baseplate components. II. Binding and location of bacteriophage-induced dihydrofolate reductase.? [/INST] The location of T4D phage-induced dihydrofolate reductase (dfr) has been determined in intact and incomplete phage particles. It has been found that phage mutants inducing a temperature-sensitive dfr (dfrts) procude heat-labile phage particles. The structural dfr produced by these ts mutants was shown to assume different configurations depending on the temperature at which the phage is assembled. Morphogenesis of incomplete phage particles lacking the gene 11 protein on their baseplates was found to be inhibited by reagents binding to dfr, such as antibodies to dfr. Further, cofactor molecules for dfr, such as reduced nicotinamide adenine dinucleotide phosphate and reduced nicotinamide adenine dinucleotide, also inhibited the step in morphogenesis involving the addition of gene 11 product. On the other hand, inhibitors of dfr, such as adenosine dephosphoribose, stimulated the addition of the gene 11 protein. It has been concluded that the phage-induced dfr is a baseplate component which is partially covered by the gene 11 protein. The properties of phage particles produced after infection of the nonpermissive host with the one known T4D mutant containing a nonsense mutation in its dfr gene suggested that these progeny particles contained a partial polypeptide, which was large enough to serve as a structural element. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Uukuniemi virus contains an RNA polymerase.? [/INST] An RNA-dependent RNA polymerase activity has been found associated with Uukuniemi virions. The enzyme activity is expressed only after disrupting the virions with the nonionic detergent Triton X-100 and is absolutely dependent on Mn2+, whereas Mg2+ is not required, a finding that distinguishes this polymerase from those of other enveloped minus-strand RNA viruses. Within the range pH 7.2 to 8.5 no distinct optimum was found. The optimum temperature was between 37 and 40 C. The reaction was not inhibited by actinomycin D, rifampin, or DNase, whereas RNase was completely inhibitory. The partially RNase-resistant product consisted of rather small-sized RNA, which contained sequences complementary to Uukuniemi virus RNA as shown by hybridization to the template L, M, and S RNA species of Uukuniemi virus. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Radiographic examination of mandibular lesions in barren-ground caribou.? [/INST] Dental anomalies were observed in 43 of 1,226 barren-ground caribou (Rangifer tarandus groenlandicus) taken between 1966 and 1968. In five of these 43 animals, the mandibles had deformities which radiography showed to be the result of dental abscesses in four cases and probably of a trauma in the other. The absence of actinomycotic lesions of the jaw bones of these 1,226 animals, and of more than 500 examined previously, indicates that "lumpy jaw" is rare in barren-ground caribou. The authors suggest the use of radiography to determine the nature of bone growth on skeletal remains, in the absence of soft tissues for examination for Actinomyces, either microscopically or by cultural methods. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Experimental diarrhea in cynomolgus monkeys by oral administration with Clostridium perfringens type A viable cells or enterotoxin.? [/INST] Purified C. perfringens type A enterotoxin fed orally in an amount of 5 mg caused both vomiting and diarrhea in the monkey only when the gastric juice had been neutralized. Exposure of enterotoxin to pH 4.0 or below rapidly destroyed the activity. All three monkeys receiving sodium bicarbonate and 2.4 X 10(10) viable cells grown in DS medium developed diarrhea, and only one of them vomited once. The diarrhea lasted for 13, 18 and 19 hr. The symptoms were similar to those reported in human cases of C. perfringens food poisoning. These results have verified the general notion that C. perfringens food poisoning should be categorized as a true "intravital intoxication". The reversed passive hemagglutination test detected enterotoxin directly in most fecal samples. This method may be applicable for diagnosis of human cases of C. perfringens food poisoning. Neither enterotoxin nor anti-enterotoxin was detected in serum samples taken from any monkey up to 21 days after the challenge. We are tempted to conclude, therefore, that no significant amount of C. perfringens enterotoxin is absorbed from the intestine. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Multiple cyclic nucleotide phosphodiesterases in rat kidney.? [/INST] Using DEAE-cellulose chromatography and Agarose gel filtration we have partially purified a low Km cyclic adenosine monophosphate (AMP) phosphodiesterase from the 100,000 X g supernatant of rat kidneys. The characteristics of this enzyme included a Km of approximately 4 muM a pH optimum of around 8.0 and a requirement for magnesium. This preparation should be suitable for investigation of possible effects of hormones, drugs and cellular constituents on the cyclic AMP pathway through any direct effects on the low Km enzyme. We have also demonstrated a nonspecific, high Km cyclic nucleotide phosphodiesterase and possibly a specific cyclic guanosine monophosphate (GMP) phosphodiesterase in the soluble fraction from rat kidneys. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect on aging on plasma renin and aldosterone in normal man.? [/INST] The influence of aging on the renin-angiotensin-aldosterone system was evaluated by comparing young (20 to 30 yr) with elderly (62 to 70 yr) healthy subjects. Despite comparable body sodium-fluid balance in the two age groups, serum renin concentration, plasma renin activity and aldosterone concentrations were lower in the elderly. The age-related decreases in circulating renin and aldosterone concentrations were slight while subjects were supine and receiving normal sodium intake; when upright and during sodium depletion, they were more pronounced. Inverse renin-blood pressure interrelations were noted during two of four study conditions involving normal sodium intake or mild sodium depletion (r = --0.44 and --0.47, respectively), but not during progressive sodium depletion. Plasma renin levels were decreased in the elderly regardless of the presence or absence of an inverse relationship with blood pressure. Aldosterone and cortisol responses to corticotropin infusion were unaltered in the elderly. It is concluded that aging may cause a decrease in circulating renin, with parallel lowering of plasma aldosterone concentrations. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [Immune mechanisms in uremia].? [/INST] There is both clinical and experimental evidence that cellular and humoral immunity are suppressed in patients with renal insufficiency: observations in organ transplantation and in vitro stimulation of lymphocytes from uraemic patients, investigations of acute and late hypersensitivity reactions, the immune response after active immunization as well as changes of immunoglobulins and lymphatic organs in uraemia are discussed in the paper. The underlying mechanisms are complex and not yet fully understood. Lymphopenia, atrophy of the thymus gland, toxic serum factors, induction of enhancing mechanisms by certain serum fractions and metabolic defects of lymphocytes--all were shown to be involved or at least considered to be. At present, however, it is impossible to define their rank of importance and the exact place they may occupy in the genesis of this type of "natural immunosuppression". </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Improvement of renin determination in human plasma using a commonly available renin standard in a radioimmunological method.? [/INST] A new method for the measurement of renin in human plasma is described. The method is based on the introduction of the internationally available renin standard of the Medical Research Council (MRC) London, as a calibration system. Thus, some principal disadvantages of methods expressing results in renin reaction velocity (angiotensin generation rate) only are avoided. Both renins, unknown and standard, react with a sheep substrate preparation and are handled identically throughout the whole procedure including the angiotensin I radioimmunoassay (RIA). The plasma renin concentration (PRC) is given in 10(-6) MRC-renin units (muM/ml). </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [Validity of pH measurements by means of micro pH combination electrodes in blood and other biological fluids (author's transl)].? [/INST] pH measurements in blood or in media containing either proteins or polypeptides and performed by means of micro pH combination electrodes type N 58 (Schott & Gen., Mainz) yield in a systematic error according to the regression line y = 1.135 chi - 0.842, in the range between pH 5.3 and 8.3. This deviation from the real pH value is independent of the protein concentration and amounts to 0.1-0.2 pH units in the physiological range. The error does not occur if the pH measurements are performed in media which are free of proteins and polypeptides, respectively. If the electrolyte solution within the reference electrode is replaced (NaCl solution instead of KCl solution) the error is distinctly reduced. For this reason, this deviation should be caused by the variation of the diffusion potential across the platinum junctions. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effects of drinking on offspring: an historical survey of the American and British literature.? [/INST] Current research on the effects on offspring of drinking during pregnancy has revived interest in an extremely old topic. Observations made during England's Gin Epidemic (1720-1750) were followed by warnings of 19th-century medical writers that parental drinking could damage the fetus. Many concurring studies were reported in the medical literature from 1865 to 1920. Research interest declined during Prohibition, and authorities later discounted the previous work. Recently a relationship between maternal drinking and abnormal morphogenesis has been again described. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [Glutathione (author's transl)].? [/INST] Glutathione plays an important role in biology and medicine. Most cells of plants and animals contain high concentrations of reduced glutathione and a much smaller amount of oxidised glutathione. GSH is important for several metabolic functions of live cells, e.g. the protection of oxidative stress by peroxides, mediation of enzyme reactions, regulation of metabolic events, transport of amino acids across cell membranes via the gamma-glutamyl cycle, elimination of foreign compounds by GSH-conjugation, release of neurotransmitter substances. Irreversible perturbations of the glutathione metabolism may be the reason for severe clinical symptoms of hemolytic anemia or, perhaps, of central nervous disease. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Hyperexcitability in the neural substrate of emotional behavior in cats after alcohol withdrawal. Evidence of a rapid development of alcohol dependence.? [/INST] Substantial and prolonged withdrawal hyperexcitability in the neural substrate for affective defense was revealed by behavioral and electrophysiological measures in cats exposed to moderate to heavy doses of alcohol for periods ranging from 6 to 72 hours. The data are interpreted as indicating a rapid development of physical dependence on alcohol in this portion of the central nervous system. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Interactions of age, sex and long-term alcohol intake in selectively bred strains of rats.? [/INST] The alcohol consumption by five genotypes of rats was studied in two experiments. Alcohol intake was age-dependent in rats bred for high emotional reactivity and avoidance conditionability. Differences in consumption by sex appeared to be primarily due to differences in body weight. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Regional study of acid hydrolases and lysosomal membrane properties in the normal human brain at various ages.? [/INST] Acid hydrolases and lysosomal membrane properties were studied at various ages in the normal human brain. In CSF and four brain regions, the inferior olive, the cerebellar cortex, the caudate nucleus and the frontal cortex were thus beta-galactosidase, beta-glucosidase, alpha-mannosidase, hexosaminidase and acid phosphatase biochemically quantitated at ages varying between 2 and 89 years of age. Also the membrane latency for acid phosphatase was studied in these regions. No major regional quantitative differences were found with regard to the enzymes studied. Their kinetic properties were also defined. There appeared to exist a regional and intra-areal variation in lysosomal membrane permeability. There was, however, no age related increase in total enzyme contents. The possibility significance of these findings are discussed with reference to the aging process. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The late effects of selected immunosuppressants on immunocompetence, disease incidence, and mean life-span. II. Cell-mediated immune activity.? [/INST] The late effects of various immunosuppressive insults on cell-mediated immunity in mice were studied in an attempt to assess the role of immune surveillance in the aging process. Results were obtained using susceptibility to allogeneic tumor cell challenge, graft-versus-host reaction (GVHR), blastogenic response to PHA, a thymus derived T cell-specific plant mitogen, and cytolytic activity against allogeneic tumor cells as measures of immunologic activity. In vivo studies late in life show that resistance to allogeneic tumor cells is significantly decreased in thymectomized mice, whereas those treated with cortisone, cyclophosphamide and sublethal X-ray remain unchanged. Spleen cells from only the thymectomized and the sublethally irradiated mice show reduced activity in the GVHR. No difference is seen in the activity of bone marrow cells. Results consistent with these findings were obtained in in vitro studies. Thus spleen cells from thymectomized or sublethally irradiated mice show decreased activity is response to PHA, whereas no change is seen in spleen cells from other treated groups. Hence, surgical and physical insults are more likely to induce long-lasting immunosuppression in those immunocompetent tissues whose activity normally diminishes with advancing age. Furthermore, the degree of immunosuppression seen in this study is not of the order of magnitude that one could reasonably predict a significant decrease in mean life-span. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Lipoxygenase isozymes of peanut.? [/INST] Lipoxygenase was isolated and partially purified from peanut seed by ammonium sulfate precipitation, gel filtration, and ion exchange column chromatography. Three isozymes of lipoxygenase were identified. Two had pH optima of 6.2, and the other an optimum of 8.3. Molecular weight of each isozyme was 7.3 x 10(4), as determined by gel filtration. The alkaline optimum isozyme was not inhibited by NaCN and was inhibited by CaCl2 except at very low concentrations. The acid optimum isozymes were inhibited by NaCN and were stimulated by CaCl2 concentrations up to ca. 0.7 mM. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Phosphate transport in rat liver mitochondria. Kinetics, inhibitor sensitivity, energy requirements, and labeled components.? [/INST] Experiments were carried out to define the kinetic parameters of the major phosphate transport processes of rat liver mitochondria, and to obtain information about the molecular properties of these systems. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about L-tyrosine: 2-oxoglutarate aminotransferase induction by hydrocortisone in the thymus of the white rat.? [/INST] Hydrocortisone hemisuccinate within 4 hours after in vivo administration produced an increase in precursor incoporation into rat thymus RNA and proteins in the whole animal. From these results, together with information obtained from measurements of the tyrosine aminotransferase activity and the action of mitomycin C administered one hour before the injection of hydrocortisone, it can be concluded that the increase in tissue level of the enzyme, consequent to hydrocortisone treatment, results from an increased rate of biosynthesis of the enzyme, which participates in the catabolic processes of proteins in glucocorticoid sensitive thymus cells. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Identification of the 30 S protein adjacent to peptidyl transferase catalytic center of Escherichia coli ribosomes.? [/INST] Iodoacetylphenylalanyl-tRNAPhe was used as an affinity label to localize the ribosomal components involved in the peptidyl transferase catalytic center of Escherichia coli ribosomes. When labeling was carried out at pH 5.0, the affinity label could specifically label the ribosomal components which comprise the catalytic center. Analysis of ribosomal proteins which had reacted with the affinity label revealed that a 30 S subunit protein, S 20, was located at or near to the ribosomal binding site of the 3'-terminus of aminoacyl- or peptidyl-tRNA. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The value of a histamine H2-receptor antagonist in the management of patients with the Zollinger-Ellison syndrome.? [/INST] Inhibition of acid secretion by an H2-receptor antagonist (metiamide) was assessed in three patients with the Zollinger-Ellison syndrome. Metiamide (200 or 300 mg) inhibited acid secretion transiently (2 1/2 hours) by 85 to 100 per cent in all patients. Although anticholinergic drugs alone inhibited acid secretion by only 0 to 35 per cent in these patients, the combination of metiamide and anticholinergic markedly prolonged the inhibitory effect of metiamide. Total gastrectomy was refused by one patient, and was impossible in another; both were treated with metiamide and anticholinergic for five and 10 months. A third patient was treated with metiamide and anticholinergic for three weeks in preparation for total gastrectomy. Ulcer pain and diarrhea disappeared, and each gained weight. H2-receptor antagonists may be useful in the treatment of some patients with the Zollinger-Ellison syndrome. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Histamine receptors in the vasculature of the rabbit ear.? [/INST] Histamine has a dual action on the isolated perfused ear preparation of the rabbit. The amine induced a dose-dependent rise in perfusion pressure when the preparation was perfused with Krebs' solution. This pressor response was reversed to a depressor effect when meypramine was added to the perfusion fluid. This depressor effect of the amine was also dose-related. Metiamide competitively inhibited the depressor effect of histamine. Prior treatment of the ear vessels with metiamide alone caused an increase in histamine-induced perfusion pressure. From these results it was concluded that the predominant pressor effect of histamine on the vascular bed of the rabbit ear is mediated through the H1-receptors and the depressor effect of the amine through histamine H2-receptors. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Relative pre- and postsynaptic potencies of alpha-adrenoceptor agonists in the rabbit pulmonary artery.? [/INST] The rabbit pulmonary artery contains postsynaptic alpha-adrenoceptors which meidate smooth muscle contraction; its noradrenergic nerves contain presynaptic alpha-adrenoceptors which mediate inhibition of the release of the transmitter evoked by nerve impulses. Dose-response curves for the pre- and postsynaptic effects of eight alpha-receptor agonists were determined on superfused strips of the artery in the presence of cocaine, corticosterone and propranolo. 1. According to the concentrations which caused 20% of the maximal contraction (EC20 post), the postsynaptic rank order of potency was: adrenaline greater than noradrenaline greater than oxymetazoline greater than naphazoline greater than phenylephrine greater than tramazoline greater than alpha-methylnoradrenaline greater than methoxamine. The pA2 values of phentolamine againstoxymethazoline, phenylephrine, alpha-methylnoradrenaline and methoxamine were 7.43, 7.48, 7.59 and 7.69, respectively. 2. For the investigation of presynaptic effects, the arteries were preincubated with 3H-noradrenaline. All agonists inhibited the overflow of tritium evoked by transmural sympathetic nerve stimulation. According to the concentrations which reduced the stimulation-induced overflow by 20% (EC20 pre), the rank order of potency was: adrenaline greater than oxymetazoline greater than tramazoline greater than alpha-methylnoradrenaline greater than noradrenaline greater than naphazoline greater than phenylephrine greater than methoxamine. 10(-5) M phentolamine shifted the presynaptic dose-response curves for moradrenaline and oxymethazoline to the right. 3. The ratio EC20 pre/EC20 post was calculated for each agonist as an index of its relative post- and presynaptic potency. According to the ratios, the agonists were arbitrarily classified into three groups. Group 1 (ratio about 30: preferentially postsynaptic agonists) comprised methoxamine and phenylephrine; group 2 (ratio near 1; similar pre- and postsynaptic potencies) comprised noradrenaline, adrenaline and naphazoline; group 3 (ratio below 0.2; preferentially presynaptic agonists) comprised oxymetazoline, alpha-methylnoradrenaline and tramazoline (as well as clonidine). 4. Preferentially presynaptic and preferentially postsynaptic agonists had opposite effects on the basoconstrictor response to nerve stimulation. Methoxamine and phenylephrine either did not change or enhanced, but never reduced, the response. In contrast, oxymetazoline, alpha-methylnoradrenaline and tramazoline at low concentrations selectively inhibited the response to stimulation at low frequency (0.25-2Hz). 5. It is concluded that alpha-adrenoceptor agonists vary widely in their relative pre- and postsynaptic potencies, possibly because of structural differences between pre- and postsynaptic alpha-receptors. Pre- and postsynaptic components contribute to their overll postsynaptic effec in actively transmitting synapses. The preferential activation of presynaptic alpha-receptors results in alpha-adrenergic inhibition of synaptic transmission. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Investigation into some imidazoline compounds, with respect to peripheral alpha-adrenoceptor stimulation and depression of cardiovascular centers.? [/INST] Peripheral alpha-adrenoceptor stimulation was tested by means of hypertensive effects of the drugs following i.v. injection in spinal rats. Naphazoline (NP), oxymetazoline (OM), St 91-2-(2,6-diethylphenylimino)-2-imidazolidine--and St 1697--2-(2-ethyl, 6-methylphenylimino)-2-imidazolidine--were 3 to 5 times more potent in tthis respect thatn clonidine (CLON) whereas St 363--2-(2,4-dichlorophenylimino)-2-imidazolidine--and xylazine (XY) exerted only approx. 1/20 the effect of that of clonidine. Sympathoinhibitory activity after i.v. injection was tested by the bradycardiac effect in vagotomized rats; St 1697, St 363 and XY were active, approx. 1/10-1/30 of CLON, whereas NP, OM and St 91 were inactive. However, following intracisternal (i.ci.) injection of cardiovascular depression, typical for clonidine: (1) in dogs with blocked beta-adrenoceptors, the drugs facilitated the vagally meditated cardiodepressor reflex in response to baroreceptor stimulation by i.v. injection of angiotensin; (2) in dogs treated with atropine and in (3) vagotomized cats (only NP, OM and St 363) a long lasting decrease in heart rate was observed. Some of the experiments were complicated by increases in blood pressure, due to the "leakage" of small amounts of the highly vasopressor active drugs, from the cisternal spaces into the peripheral circulation. The majority of results indicated, that the central cardiovascular depressor effects of the tested drugs depend on their alpha-adrenoreceptor stimulating potency and on their ability to penetrate from cerebrospinal fluid or from the blood to cardiovascular centers. Relationships between the ability for penetration and the lipoid affinity are discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The regulation of striatal tyrosine hydroxylase. Effects of gamma hydroxybutric acid and healperidol.? [/INST] Gamma-hydroxybutyric acid (GHBA) in doses that increased the striatal dopamine (DA) content of rat brain failed to increase the affinity of striatal tyrosine hydroxylase (TH) for its pterdine cofactor or to change the sensitivity of the enzyme to the inhibition by DA. Haloperidol (1 mg/kg) decreased the apparent Km of striatal TH for the pteridine cofactor. However, when GHBA was injected before haloperidol it prevented the decrease in the apparent Kn of TH, in a dose related manner. In vitro GHBA (10(-4) M) neither changed the stimulation of the striatal adenylyl cyclase by DA nor its inhibition by haloperidol. These results suggest that in striatal dopaminergic terminals the Kn of TH for the pteridine cofactor is regulated by an molecuular mechanism which requires that the impulse flow in the DA neurons is unimpaired. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Influence of peritoneal dialysis on factors affecting oxygen transport.? [/INST] To determine the effect of changing concentrations of uremic metabolites on factors affecting oxygen transport, without the effects of extracorporeal blood pumping, we studied five patients before, during and after peritoneal dialysis. Significant decreases in serum urea, creatinine and phosphate and increase in serum bicarbonate were not associated with changes in P50, a reflection of hemoglobin-oxygen affinity. High erythrocyte 2,3-DPG concentrations decreased only slightly. Arterial pO2 increased slightly as negative fluid balance was achieved. The slight changes in oxygen transport parameters with dialysis suggest an interplay of compensatory factors and do not warrant modifying dialysis to limit the correction on acidosis or hyperphosphatemia. Effects on hemoglobin and pO2 resulting from fluid loss can be the dominant influence of peritoneal dialysis on tissue oxygenation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Some effects of ammonium salts on renal histology and function in the dog.? [/INST] NH4Cl was infused into the left renal artery of anesthetized dogs at 50-125 mum/kg/min for up to 110 min. Renal blood flow declined early then increased to supra-control levels during infusion. Kidneys perfused at 125 mum/kg/min for 90 min showed patchy to confluent mixtures of cortical necrosis and tubular necrosis. Experimental kidneys invariably showed lower urine osmolality than contralateral controls 48 h after perfusion. Kidneys with necrosis showed depressed creatinine clearance as well. Renal artery infusion of NH4 acetate or intravenous infusion of NaHCO3 during arterial infusion of NH4Cl prevented significant acidosis and caused minimal histological changes, but depression of urine osmolality was not prevented. It is concluded that renal ammonium concentrations up to 40 mum/liter for 90 min does not cause tubular necrosis but does impair urine concentration. Severe tissue damage followed renal exposure to high ammonium concentrations in the presence of metabolic or renal acidosis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Papillary necrosis associated with calyceal arteritis.? [/INST] The renal papilla has a double blood supply - from both the vasa recta and the calyceal arteries. The importance of the latter supply is not established. A case of polyarteritis associated with papillary necrosis is reported, in which the calyceal vessels, supplying the area, show acute necrotizing arteritis and occlusion. The pathophysiological and clinical implications are discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Fasting uric acid and phosphate in urine and plasma of renal calcium-stone formers.? [/INST] Clearance experiments in calcium-stone patients (n = 60) and controls (n = 60) demonstrated significantly higher urinary uric acid (UA) in younger (less 40 years) stone patients than controls (median: 480 vs. 351 mug/min) but not in older (greater than 40 years) patients. Serum UA and urinary oxypurines were comparable in health and stone disease. Conversely urinary phosphate was significantly lower in younger patients than matched controls (males: 224 vs. 304 mug) and presumably is responsible for the more alkaline pH. It is suggested that calcium-stone formation in humans is represented by two different populations. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effects of varying dialysate calcium concentrations on the plasma calcium fractions in patients on dialysis.? [/INST] The plasma-ionized calcium levels decreased during haemodialysis when a dialysate calcium concentration of 5 mg/100 ml was used. When dialysis was performed with a bath calcium concentration of 7.5 mg/100 ml, there was a significant increase in the plasm-ionized calcium levels in the post-dialysis period. These results are discussed in relation of the optimal dialysate calcium concentrations and development of dialytic bone disease. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Identification, purification and properties of clone-specific glycoprotein antigens constituting the surface coat of Trypanosoma brucei.? [/INST] Soluble glycoproteins have been purified from a series of clones of Trypanosoma brucei 427. Each clone yielded a characteristic predominant glycoprotein which induced clone-specific immunity to trypanosome infection in mice. These glycoproteins were shown by specific labelling and enzyme digestion of cells to be the major components of the trypanosome surface coat. Each glycoprotein consisted of a single polypeptide chain having an apparent molecular weight of 65 000 (as measured by SDS-polyacrylamide gel electrophoresis) and containing around 600 amino acid and 20 monosaccharide residues. Preliminary structural studies indicated large changes in amino acid sequence dispersed over a considerable length of the polypeptide chain. Proteolytic activity was demonstrated in semi-purified trypanosome extracts, providing one reason for the heterogeneity sometimes observed in surface glycoprotein antigen preparations. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The determination of gamma-glutamyl transpeptidase by reaction rate assay at 37 degrees C.? [/INST] The determination of gamma-glutamyl transpeptidase by a reaction rate assay using optimal reaction conditions at 37 degrees is described. Specific conditions and instrument settings are described for the LKB Reaction Rate Analyser but the actual assay conditions are applicable to any similar reaction rate system. The precision of the method has been evaluated and a reference range for normal male (less than 45 U/l) and female (less than 30 U/l) subjects determined. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The influence of cortisol on the enzymes of fatty acid synthesis in developing mammalian lung and brain.? [/INST] Administration of cortisol to fetal rabbits resulted in a 42% inhibition of pulmonary de novo fatty acid synthesis from acetyl coenzyme A (CoA) (P = less than 0.025). This was associated with inhibition of acetyl-CoA carboxylase (EC. 6.4.1.2.) activity (P = less than 0.01) and a tendency towards decreased activity of fatty acid synthetase. There was no effect on pulmonary microsomal fatty acid elongation activity. Light and electron microscopic examination of the apex of the right lung of control and cortisol-treated animals revealed changes consistent with accelerated lung maturation in the treated animals. The in vitro activities of acetyl-CoA carboxylase and fatty acid synthetase were similar in rabbit lung and thus acetyl-CoA carboxylase activity does not appear to be rate limiting for de novo fatty acid synthesis in lung. No significant change in the activity of enzymes associated with de novo fatty acid synthesis of microsomal fatty acid elongation was found in fetal brain after cortisol exposure. However, in a parallel study on fatty acid synthesis in fetal liver, cortisol administration resulted in a 30% increase in fatty acid synthetase activity (P less than 0.025). The finding of cortisol-induced inhibition of de novo fatty acid synthesis in fetal rabbit lung may be related to the known inhibitory effect of cortisol on lung growth in the fetus. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The relation between myosin adenosinetriphosphatase activity and inactivation of myosin under alkaline conditions of heart muscles in mammals of different size.? [/INST] ATPase activity of myosin in the heart muscle of the mouse, rat, guinea-pig, rabbit and pig was studied at neutral pH and under mild alkaline conditions. At neutral pH the ATPase activity of myosin is inversely related to body size of the animal species. The decrease of ATPase activity of myosin after alkaline preincubation depends on the degree of ATPase activity of intact myosin, i.e. myosin from the heart of the mouse exhibits high ATPase activity ae same relationship was found, when comparing myosin of new-born and adult heart muscle. It is concluded that the rate of alkaline inactivation of heart myosin is directly related to the degree of ATPase activity of intact myosin in all animals. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Carbon dioxide response curves during hypothermia.? [/INST] The responsiveness of the medullary chemoreceptors, measured by the ventilatory response to hypercapnia given in an hyperoxic gas mixture in intact anesthetized dogs has been evaluated during normothermia and at two levels of hypothermia. The response was studied in: 1) 20 dogs during normothermia, 2) 10 of these dogs at a blood temperature of 32-33 degrees C, and 3) in the other 10 dogs during deeper hypothermia (28-29 degrees C). The ventilatory response to CO2 decreased while blood temperature was lowered until the response became absent during deep hypothermia. For normothermia and both levels of hypothermia a similar oxygen drive of ventilation was found which was equivalent to approximately one fourth of the spontaneous ventilation. It is suggested, that in the deeply hypothermic animal the normal respiratory drive is apparently of peripheral (arterial) chemoreceptor origin and when this drive is nullified or significantly decreased, gentle shivering could be responsible for stimulating the respiratory center. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Catalysis by acetylcholinesterase: evidence that the rate-limiting step for acylation with certain substrates precedes general acid-base catalysis.? [/INST] Inferences about the catalytic mechanism of acetylcholinesterase (acetylcholine hydrolase, EC 3.1.1.7) are frequently made on the basis of a presumed analogy with chymotrypsin, EC 3.4.21.1. Although both enzymes are serine hydrolases, several differences in the steady-state kinetic properties of the two have been observed. In this report particular attention is focused on the second-order reaction constant, kcat/Kapp. While the reported pH dependence and deuterium oxide isotope effect associated with this parameter for chymotrypsin are generally consistent with simple models involving rate-limiting general acid-base catalysis, this study finds a more complicated situation with acetylcholinesterase. The apparent pKa of kcat/Kapp for acetylcholinesterase varies between 5.5 and 6.3 for neutral substrates and involves nonlinear inhibition by [H+]. Deuterium oxide isotope effects for kcat/Kapp range from 1.1 for acetylcholine to 1.9 for p-nitrophenyl acetate. The bimolecular reaction rate appears rate-limiting for acetylcholine at low concentrations, while a rate-limiting induced-fit step is proposed to account for apparent pKa values and low deuterium oxide isotope effects associated with low concentrations of phenyl acetate and isoamyl acetate. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Light-dependent absorption and selective scattering changes at 518 nm in chloroplast thylakoid membranes.? [/INST] The light-induced absorbance change at 518 nm of isolated chloroplasts consists of a rapid phase, and a slow phase which is complete in about 20 sec. The slow component of the 518 nm absorbance change correlates with the light-induced change in 90 degrees light scattering at 518 nm. Both show a similar time course, similar pH dependence with a maximum at pH 6.0, and similar sensitivity to inhibitors and to treatment of the chloroplasts with a low concentration of glutaraldehyde. Their light minus dark difference spectra are similar with maxima at about 520 nm. It is concluded that they are manifestations of the same phenomenon, and the slow absorbance increase at 518 nm is due to enhanced scattering. It is proposed that the light-induced changes in scattering at 518 nm reflect alterations in selective dispersion, due to proton uptake and conformational changes in the chloroplast thylakoid membrane. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about phiX174 DNA-dependent DNA synthesis in vitro: requirement for P1 ban protein in dnaB mutant extracts of Escherichia coli.? [/INST] Ammonium sulfate fractionation of crude extracts of E. coli yields a soluble enzyme fraction (about 25-fold purification) that catalyzes the conversion of phiX174 single-stranded DNA to duplex DNA. The reaction is rifampicin-resistant, requires single-stranded DNA, Mg++, deoxynucleoside triphosphates, and ATP, and is stimulated by KCl. Such soluble enzyme fractions were prepared from E. coli strains carrying the prophage mutant P1bac, in which the viral dnaB analog (ban) protein is expressed constitutively, or P1bacban, in which the expression of ban protein is prevented. DNA-synthesizing activity of ban protein containing fractions from wild-type or dnaB(P1bac) lysogens was more temperature-resistant than that from E. coli containing only wild-type dnaB protein, whereas that from dnaB(P1bacban) lysogens of dnaB cells was extremely thermolabile. It is suggested that the temperature-resistant DNA synthesis with fractions from P1bac lysogens is mediated by the P1 ban protein. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Intramolecular arsanilazotyrosine-248-Zn complex of carboxypeptidase A: a monitor of catalytic events.? [/INST] The intensely chromophoric intramolecular coordination complex formed between arsanilazotyrosine-248 and the active site zinc atom of azocarboxypeptidase A (Johansen, J. T. & Vallee, B. L. (1971) Proc. Nat. Acad. Sci. USA 68, 2532-2535) is a spectrokinetic probe of catalytic events. The interconversion of the azoTyr-248-Zn complex and its constituents is measured by stopped-flow pH and temperature-jump methods. The rate of interconversion, 64,000 sec-1, is orders of magnitude faster than that of the catalytic step itself (about 0.01-100 sec-1). Rapidly turned over peptide and ester substrates disrupt the azoTyr-248-Zn complex before hydrolysis occurs. As a consequence, formation of azoTyr-248, substrate binding, and catalysis can all be monitored while catalysis is actually in progress. The results of these dynamic studies specify a course of catalytic events, different from those postulated based on x-ray structure analysis. If azoTyr-248 is displaced, the direction is opposite to the inward movement postulated on the basis of x-ray studies and is not unique to induction by substrates, since rapid changes in pH also result in analogous spectral changes. AzoTyr-248 carboxypeptidase has all the features which are essential for mechanistic studies: (1) It is enzymatically active; (2) the spectra of the metal complex differ characteristically from those of its constituents; (3) it responds dynamically to environmental factors; and (4) the response time of the probe itself is much more rapid than is required for the measurement of the catalytic step. These combined kinetic and spectral properties of the metal complex render it a powerful spectrokinetic probe to visualize and discern microscopic details of the catalytic process. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Ubiquinone-mediated coupling of NADH dehydrogenase to active transport in membrane vesicles from Escherichia coli.? [/INST] Addition of ubiquinone-1 to E. coli ML 308-225 membrane vesicles dramatically increases coupling between NADH oxidation and active transport such that initial rates and steady-state levels of lactose and amino-acid accumulation are comparable to those observed during D-lactate oxidation. Similar but less dramatic effects are observed with the quinone and succinate or L-lactate. In the presence of NADH and ubiquinone-1, the vesicles also generate a membrane potential (interior negative) that is similar in magnitude to that observed in the presence of D-lactate. Stimulation of NADH-dependent transport by ubiquinone-1 cannot be accounted for by increased rates of oxidation of NADH, and the effect of the quinone on NADH-dependent lactose transport is not observed in vesicles depleted of NADH dehydrogenase activity. Thus, it is apparent that ubiquinone-1 shunts electrons from NADH dehydrogenase [NADH:(acceptor)oxidoreductase; EC 1.6.99.3] to the portion of the respiratory chain containing the energy-coupling site. The findings demonstrate unequivocally that inefficient coupling of NADH oxidation to active transport cannot be due to the presence of inverted vesicles. In addition, they provide further support for specific localization of the energy-coupling site. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Protection of lethally irradiated mice with allogeneic fetal liver cells: influence of irradiation dose on immunologic reconstitution.? [/INST] After lethal irradiation long-lived, immunologically vigorous C3Hf mice were produced by treatment with syngeneic fetal liver cells or syngeneic newborn or adult spleen cells. Treatment of lethally irradiated mice with syngeneic or allogeneic newborn thymus cells or allogeneic newborn or adult spleen cells regularly led to fatal secondary disease or graft-versus-host reactions. Treatment of the lethally irradiated mice with fetal liver cells regularly yielded long-lived, immunologically vigorous chimeras. The introduction of the fetal liver cells into the irradiated mice appeared to be followed by development of immunological tolerance of the donor cells. The findings suggest that T-cells at an early stage of differentiation are more susceptible to tolerance induction than are T-lymphocytes at later stages of differentiation. These investigations turned up a perplexing paradox which suggests that high doses of irradiation may injure the thymic stroma, rendering it less capable of supporting certain T-cell populations in the peripheral lymphoid tissue. Alternatively, the higher and not the lower dose of irradiation may have eliminated a host cell not readily derived from fetal liver precursors which represents an important helper cell in certain cell-mediated immune functions, e.g., graft-versus-host reactions, but which is not important in others, e.g., allograft rejections. The higher dose of lethal irradiation did not permit development or maintenance of a population of spleen cells that could initiate graft-versus-host reactions but did permit the development of a population of donor cells capable of achieving vigorous allograft rejection. These observations contribute to understanding of some of the persisting immunodeficiencies that are observed in man after fatal irradiation and bone marrow transplantation. These results should suggest better approaches to more effective cellular engineering for correction of immunodeficiency diseases and for treatment of immunodeficiency diseases and of leukemias and malignancies of man. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Mechanism of action of penicillin: triggering of the pneumococcal autolytic enzyme by inhibitors of cell wall synthesis.? [/INST] During penicillin treatment of an autolysin defective mutant pneumococcus we have observed three novel phenomena: (i) Growth of the mutant cultures is inhibited by the same concentrations of penicillin that induce lysis in the wild type. (ii) Mutant bacteria treated with the minimum growth inhibitory concentration of penicillin will lyse upon the addition of wild-type autolysin to the growth medium. Chloramphenicol and other inhibitors of protein synthesis protect the cells against lysis by exogenous enzyme. Sensitivity of the cells to exogenous autolysin requires treatment with penicillin or other inhibitors of cell wall synthesis (e.g., D-cycloserine or fosfonomycin) since exogenous autolysin alone has no effect on bacterial growth. (iii) Treatment with penicillin (or other inhibitors of cell wall synthesis) causes the escape into the medium of a choline-containing macromolecule that has properties suggesting that it contains pneumococcal lipoteichoic acid (Forssman antigen). Each one of these three phenomena (growth inhibition, sensitization to exogenous autolysin, and leakage of lipoteichoic acid) shows the same dose response as that of the penicillin-induced lysis of wild-type pneumococci. On the basis of these findings we propose a new hypothesis for the mechanism of penicillin-induced lysis of bacteria. It is suggested that inhibition of cell wall synthesis by any means triggers bacterial autolytic enzymes by destabilizing the endogenous complex of an autolysin inhibitor (lipoteichoic acid) and autolytic enzyme. Escape of lipoteichoic acid-like material to the growth medium is a consequence of this labilization. Chloramphenicol protects bacteria against penicillin-induced lysis by interfering with the activity of the autolytic enzyme, rather than by depleting the concentration of the enzyme at the cell surface. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Identification of NADPH-thioredoxin reductase system in Euglena gracillis.? [/INST] Euglena gracilis contains a protein system which can utilize the reducing power of NADPH in the ribonucleotide reductase-catalyzed reduction of CTP. The proteins required for this reaction are a flavoprotien with a molecular weight of approximately 185,000 which is functionally similar to thioredoxin reductase (NADPH), EC 1.6.4.5, and another protein (Protein I) whose function in the reaction is unknown. This new protein does not appear to contain a prosthetic group and has a molecular weight of approximately 240,000. In addition, the ribonucleotide reductase active in the Euglena NADPH-thioredoxin reductase system is more complex than the protein reported in a previous publication [(1974) j. Biol. Chem. 249, 4428-4434]. The enzyme preparation described in this report contains four different types of polypeptide chains which may complex to form the active enzyme. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Purification of folate binding factor in normal umbilical cord serum.? [/INST] Human umbilical cord serum was found to contain both free folate and folate complexed to a high-molecular weight factor. The complexed folate was bound to a very high affinity binder and was present in concentrations equivalent to as much as 60 ng of 5-methyltetrahydrofolic acid per ml of serum. Acidification of the serum caused disassociation of the folate-binder complex. Released folates were separated from binder by Sephadex gel filtration, zonal centrifugation through sucrose gradients, or adsorption onto activated charcoal. The separated binding factor, either saturated or unsaturated with folate, had a molecular weight of about 40,000 on Sephadex G-200 chromatography. Binding of [3H]pteroylglutamic acid was rapid and, as in the original endogenous folate-binder complex, was essentially irreversible at neutral pH. The affinity and specificity of the binder were examined by competition experiments using [3H]pteroylglutamic acid and nonradioactive folate derivatives. Oxidized folates were bound in preference to reduced derivatives, but only three to four times more unlabeled 5-methyltetrahydrofolic acid than pteroylglutamic acid was required to produce an equal level of competition. The strong affinity for 5-methyltetrahydrofolic acid, the main serum folate, suggests that the binder could be part of the mechanism by which the fetus concentrates maternally supplied folate for its growth and development. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Intramolecular arsanilazotyrosine-248-Zn complex of carboxypeptidase A: a monitor of multiple conformational states in solution.? [/INST] The red azoTyr-248-Zn complex of arnilazocarboxypeptidase, previously used to demonstrate differences in conformation of the enzyme in crystals and in solution, has now provided means to detect multiple conformations of the enzyme in solution by stopped-flow pH and temperature jump experiments. These studies identify two distinct processes. Er + H+ in equilibrium Ey (I), is the extremely rapid, Kfast about 10(5) sec-1, pH dependent dissociation of the metal complex. Ey in equilibrium Ey' (II), is much slower, Kslow about 5 sec-1, pH independent interconversion of two distinct populations of protein molecules, Ey and Ey', in which the yellow azo-Tyr-248 is different conformations. These two conformations can be differentiated readily by stopped-flow pH-jump experiments, since I is three to four orders of magnitude faster than II. Mathematical expressions derived from this mechanism accurately predict all observations over the pH range from 6.0 to 8.5. In a previous stopped-flow pH-jump experiment, Lipcomb and coworkers [Quiocho, F. A., McMurray, C. H. & Lipcomb, W. H. (1972), Proc. Nat. Acad. Sci. USA 69, 2850-2854] recognized only a single process with a rate constant of about 6 sec-1, but not the major, very rapid rate observed here. The failure to detect this fast process led to the postulation of a number of explanations intended to account for the detection of only a single, slow rate. The present observations show that the premise for those conjectures is not valid. The azoprobe reveals the existence of rapidly interconvertible substructures of carboxypeptidase A, and the results support the view that in solution, enzymes can adopt multiple, readily interconvertible and related conformations which could then either facilitate or impede catalysis. In crystals, rearrangement of molecular structure could be severely impaired or restricted, and crystallization might single out either active or inactive conformations. In the latter case, such crystals would have greatly reduced activities and markedly altered catalytic behavior, as is observed for carboxypeptidase A. In combination with detailed kinetic analysis of crystals, conformational analysis in solution should be a valuable guide to discern enzyme mechanisms and select crystals for x-ray structure analysis. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Presence of norepinephrine and related enzymes in isolated brain microvessels.? [/INST] Norepinephrine and the enzymes involved in its synthesis and degradation were found to be associated with isolated brain microvessels. The significance of these results are discussed with respect to adrenergic innervation of the cerebral microvessels and thereby neural regulation of the cerebral microcirculation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effect of L-dopa on young patients with simple schizophrenia, treated with neuroleptic drugs: a double-blind cross-over trial with Madopar and placebo.? [/INST] Thirteen out of 18 young out-patients with simple schizophrenia under neuroleptic treatment completed a double-blind cross-over trial with Madopar [L-Dopa + benserazid (a peripheral decarboxylase inhibitor)] and placebo. Nine patients were given 900 mg L-Dopa + 225 mg benserazid daily, 1 patient received 600 mg L-Dopa + 150 mg benserazid, and 3 patients, 300 mg L-Dopa + 75 mg benserazid. In these doses, L-Dopa was effective against emotional withdrawal, blunted affect, tendency to isolation and apathy, without inducing or aggravating productive, accessory symptoms. The activity score, according to the specific activity-withdrawal scale, was significantly increased (P less than 0.05), whereas the total BPRS score (Brief Psychiatric Rating Scale) was slightly, but significantly reduced (P less than 0.05). In cases where L-Dopa had to be limited to 600 and 300 mg daily, a tendency to anxiety, distortion of thinking, and a sense of unreality were observed, depending on the dose of L-Dopa. In no case were gastrointestinal, cardiovascular or neurological side-effects observed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The specificity of binding of the narcotic agonist etorphine in synaptic membranes of rat brain in vivo.? [/INST] When 3H-etorphine was administered to rats in a pharmacologically effective dose (0.75 mug/kg intracisternally), the labeled drug was concentrated in synaptic membrane fractions isolated from the brains of rats killed 10 min after etorphine injection. Pretreatment of the animals with the narcotic antagonists naloxone, diprenorphine or l-cyclorphan, blocked the pharmacological responses to etorphine and reduced 3H-etorphine binding in the membrane fractions. The differences between 3H-etorphine bound in synaptic membranes of rats treated with d-cyclorphan (inactive isomer) and l-cyclorphan (active antagonist) were in the same range as the reductions in etorphine binding in antagonist-treated rats, indicating that stereospecific and pharmacologically-specific binding sites in synaptic membranes in vivo were of the same magnitude: about 0.04 pmol/g brain. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The cholinergic system and nociception in the primate: interactions with morphine.? [/INST] In Experiment 1 the shock titration task was used to evaluate the antinoceptive properties of 5 different classes of cholinergic compounds in the rhesus monkey. Only scopolamine and high doses of physostigmine were effective in elevating the shock threshold. The apparent antinociceptive effect of physostigmine, however, was difficult to separate from its nonspecific behavioral depressant effect and was probably not related to an increase in cholinergic tone. Experiment 2 examined the interaction of morphine with arecoline, scopolamine and physostigmine. Only scopolamine (0.05 and 0.1 mg/kg) and high doses of physostigmine (0.1 mg/kg) interacted with morphine in the shock titration paradigm. The multiplicative interaction of morphine with scopolamine was confirmed in Experiment 3 over a wider range of doses. It was concluded that morphine and the cholinergic compounds produce antinociceptive effects through different mechanisms of the pain system. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effects of thienodiazepine derivatives on human sleep as compared to those of benzodiazepine derivatives.? [/INST] The effects of new thienodiazepine derivatives, such as clotiazepam and Y-7131, on normal human sleep were investigated on 5 subjects and compared to those of benzodiazepine derivatives, such as diazepam and nitrazepam. REM sleep was significantly decreased only with 2 mg of Y-7131 and rebound elevation of REM sleep did not follow in recovery 1 and 2 nights. By using partial differential REM deprivation which was designed by us, there was also no rebound elevation of REM sleep noted in recovery 2 nights following 2 mg of Y-7131 medication. REM sleep was not suppressed with 15 mg of clotiazepam, 6 mg of diazepam and 10 mg of nitrazepam when compared to the baseline night. With regard to NREM sleep, stage 2 was significantly increased with 15 mg of clotiazepam and 10 mg of nitrazepam, but stage SWS was significantly decreased with 10 mg of nitrazepam. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effect of two weeks' treatment with thioridazine, chlorpromazine, sulpiride and bromazepam, alone or in combination with alcohol, on learning and memory in man.? [/INST] Forty paid healthy male students participated in two subacute experiments of 6 weeks each. In the first trial 20 of them received bromazepam, thioridazine, and placebo double blind cross over for 2 weeks each, and in the second trial the active agents administered to the other 20 participants were chlorpromazine and sulpiride. The tests used were paired associate learning with nonsense syllables and digit memory span. Before testing the subjects took either an alcoholic or a nonalcoholic bitter drink. As in the previous study from this laboratory, alcohol was found to impair learning capacity. Of the drugs used only bromazepam impaired learning significantly, and the combined effect of alcohol and bromazepam on learning capacity was very deleterious. The adrenolytic effect of drugs did not correlate with their effect on learning. Caution is necessary when prescribing bromazepam for active outpatients at least in doses used in this study. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effects of chronic exposure to stressors on avoidance-escape behavior and on brain norepinephrine.? [/INST] A single exposure to a severe stressor (either cold swim or inescapable shock) impairs subsequent performance in a shuttle avoidance-escape task (1), a deficit attributed to reduction in brain noradrenergic activity produced by these stressors. In the present paper, two experiments are described which examine how repeated exposure to such stressors affects (a) shuttle avoidance-escape performance (Experiment 1), and (b) aspects of brain norepinephrine metabolism (Experiment 2). Experiment 1 showed that, whereas subjects receiving the single exposure to cold swim or shock showed a large avoidance-escape deficit, subjects that received repeated exposure to these stressors for 14 days performed similarly to the control group that received no stressor. Experiment 2 showed that, whereas subjects that received one session of the inescapable shock stressor showed a lower level of norepinephrine in hypothalamus and cortex than did subjects that received no shock, subjects that received repeated exposure to inescapable shock or cold swim showed neurochemical "habituation." Subjects that received repeated shock showed elevated tyrosine hydroxylase activity and no depletion of norepinephrine level, and both repeated shock and cold swim caused a decrease in uptake of 3H-norepinephrine by slices of cortex in vitro. Thus, it is concluded that the behavioral and neurochemical changes that were observed after the stressful conditions studied are consistent with the hypothesis that changes in avoidance-escape responding following exposure to these stressful events are due to changes in brain noradrenergic activity. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Evaluation of combined pharmacological and psychotherapeutic treatment in patients with functional abdominal disorders.? [/INST] 78 patients suffering from various functional abdominal complaints have been trated in a 2 x 2 double-blind design: (a) psychotherapy with Ro 5-3350 (TH/Ro); (b) psychotherapy with placebo (TH/P); (c) Ro 5-3350 without psychotherapy (NIH/Ro); (d) placebo without psychotherapy (NTH/P). Results show that a considerable amount of improvement cannot be ascribed to the two critical factors or the interaction of both, but are due to unspecific influences in the course of treatment. Some of the results concerning the combination of TH and the psychotropic drug pose interesting questions for further research and bare implications for double-blind trials of psychotropic drugs. The results suggest that possibly properties of any psychotropic drug have to be related to a doctor-patient relationship within which the personal problems of the patient are dealt with. In order to evaluate such properties, special methodological precautions have to be taken. These will be briefly discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [Pressures, blood gases, pH, lactate and pyruvate concentrations in the portal venous blood in patients after laparotomy during the first 9 days (author's transl)].? [/INST] In 24 patients (16 women, 8 men, mean age 60 years), who underwent abdominal operations and who had a uncomplicated postoperative course, a teflon-tube was inserted into the portal vein at the end of laparotomy and remained there for maximal 9 days. The mean values of the portal venous pressure as well as of the portal-central venous pressure gradient are unchanged during the period of all 9 days and are between 7,4 and 7,9 mmHg, between 5,6 and 6,9 mmHg respectively. The arterio-portal venous 0(2)-content difference shows in the mean no fluctuations and is about 2 Vol.%. On the first postoperative day the lactic and pyruvic acid concentrations in the artery and portal vein are moderately, but significantly elevated and decrease to normal values until day 7. - 9. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Biochemical and biophysical changes in guinea pigs after acute head injury.? [/INST] Animal experiments were set up mainly to derive additional diagnostic data from the study of biochemical changes after acute head injury. In standardized experiments guinea pigs were subjected in groups of 20 to three identical head injuries, each of either 1.0 J or 1.5 J intensity. The trauma was likely to result in a concussion or contusion syndrome similar to that found in man; 40 animals served as controls. During the 60 min after injury observation and measurement of body functions did not reveal signs of a shock-like condition or hypoxaemia in the traumatized animals compared with control animals. Superficial anaesthesia probably did not influence the findings. Temperature and respiration were altered significantly in all the animals receiving head injuries. Blood gas analysis showed a decrease of standard bicarbonate only after the 1.5 J injury but even though hypoxaemia was not present 2,3-diphosphoglycerate values and P50 increased, compared with the control animals. The fall of plasma lipid concentrations reported probably had to be seen as a sympathomimetic effect of the minor (1.0 J) trauma. Of special significance was the increased activity of malate dehydrogenase and aldolase, found only in the blood of severely traumatized animals, as this could serve as an early diagnostic aid for evaluating head injuries. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Total brain ischaemia in dogs: cerebral physiological and metabolic changes after 15 minutes of circulatory arrest.? [/INST] Cross-clamping of the ascending aorta in dogs for 15 min produced severe neurological deficit, observed for up to 20 h. Immediately after restoration of the circulation, the intracranial pressure in the cisterna magna increased transiently to a mean peak of 22.8 Torr (SD +/- 1.7) because of a compensatory increase in systemic arterial pressure, without a fall in cerebral perfusion pressure. The intracranial pressure returned to control values 15-30 min after ischaemia and showed no secondary rise during the 8 h of observation. The electroencephalogram became isoelectric 34 +/- 6.5 s (mean +/-SD) after circulatory occlusion, and was abnormal when it reappeared 5 h 36 min (SD +/- 2 h 4 min) after the circulation was restored. The electrical impedance of the brain increased immediately after ischaemia and returned rapidly towards pre-ischaemic values during re-perfusion. The cerebral water had not increased measurably 4 h after ischaemia. After ischaemia, the lactate concentration in the cerebrospinal fluid increased to 4.7 mequiv./1(SEM +/-0.1) and the pH decreased to 7.17 (SEM +/-0.02); both returned to control values after 3.5 h. The cerebral glucose uptake was decreased 35 min after ischaemia, cerebral oxygen uptake remained unchanged but cerebral blood flow decreased (P less than 0.05 at 90 min). Immediately after cardiac arrest, recovery was impaired more by the presence of focal abnormal brain perfusion than by intracranial hypertension. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Oxygen and carbon dioxide dissociation of duck blood.? [/INST] Oxygen and CO2 dissociation of duck blood was studied in blood samples equilibrated with known gas mixtures at the bird's body temperature (41 degrees C) and analyzed in the Van Slyke manometric apparatus and in pH electrodes. At various pH values between 7.38 and 7.55 the Hill plots yielded straight and parallel lines over a wide range of O2 saturation, the Hill coefficient being 2.9. Half saturation pressure P50 at pH = 7.50 was 36 torr. The Bohr effect factor was -0.53. Buffering properties were analyzed by equilibrating blood samples with gas mixtures of different PCO2 at 41 degrees C. The buffer value for whole blood in the range of 3-7% CO2 was 19.3 mMol-L-1-pH-1, the buffer value for true plasma 22.9 mMol-L-1-pH-1. The CO2 dissociation curve constructed using the buffer values had a slope of 0.17 mMol-L-1-torr-1 in the PCO2 range from 40 to 50 torr. The CO2 content of oxygenated blood at PCO2 = 40 torr was 21.7 mMol-L-1. The Haldane effect factor at PCO2 = 35 torr equalled 0.30 mMol of combined CO2 per mMol HbO2. With the values of PO2, PCO2 and pH measured in arterial blood of undisturbed and unrestrained, resting ducks effective dissociation curves for both O2 and CO2 were constructed assuming a metabolic R.Q. of 0.8. These curves are expected to resemble closely the actual in vitro dissociation curves of resting ducks. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about First apparent dissociation constant of carbonic acid, pK'1, of plasma and erythrocytes.? [/INST] The first apparent dissociation constant of carbonic acid, pK'1, of plasma and red cells was determined on venous blood of ten healthy, adult, male, human subjects. pH and PCO2 of plasma and red cells were analyzed electrometrically and a micromanometric method was used for the determination of total carbon dioxide content. Erythrocyte carbamino hemoglobin levels were estimated and used for the correction of erythrocyte pK'1. Each blood sample was subjected to the following regimen before centrifugation, 1) As drawn from the antecubital vein, 2) Oxygenated with a 5% CO2, O2 balance gas mixture, and 3) Reduced with a 5% CO2, N2 balance gas mixture. pK'1 of plasma and red cells are presented: (see article). The consistently larger values for red cell pK'1 than the respective plasma data may be attributed to the greater amount of carbamino hemoglobin concentration present in the erythrocytes. A simplified method for the calculation of erythrocyte bicarbonate concentration using the experimentally determined red cell pK'1 value has been formulated. The method involves the use of a regression equation relating plasma and red cell pH, the equivalence of plasma and red cell PCO2, along with the experimentally determined red cell pK'1. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effects of changes in pH and PCO2 in blood and water on breathing in rainbow trout, Salmo gairdneri.? [/INST] The effect of sustained hypercapnia on the acid-base balance and gill ventilation in rainbow trout, Salmo gairdneri, was studied. The response to an increase in PICO2 from 0.3 to 5.2 mm Hg was a five-fold increase in gill ventilation volume and a slight increase in breathing frequency. There was a concomitant rise in PACO2 and an immediate fall in pHa. If PICO2 was maintained at 5.2 mm Hg for several days, ventilation volume gradually returned to the initial, prehypercapnic level within three days. Arterial pH also returned to the initial level within 2-3 days. These results are consistent with the hypothesis that under these conditions fish regulate pH via HCO3/C1 exchange across the gills rather than by changes in ventilation and subsequent adjustment of PACO2. A reduction in environmental pH causes a reduction in pHa but only a slow gradual increase in VG. Injections of HC1 or NaHCO3 into the blood have opposite effects on pHa but both cause a marked increase in VG. It is concluded that a rise in PACO2 results in a rise in VG and that changes in pH in blood or water have little direct effect on VG in rainbow trout. Possible location for receptors involved in this reflex response are discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effect of pH upon fluoride uptake in intact enamel.? [/INST] The relationship between pH and fluoride uptake in intact enamel of permanent premolars was investigated by using: (1) a sodium fluoride dentifrice, (2) a potassium fluoride + manganese chloride dentifrice, and (3) a sodium fluoride solution of the same fluoride concentration. The first part of this paper deals with the in vitro uptake of fluoride from dentifrice slurries and from sodium fluoride solutions of different pH ranging from 7.1 to 4.5. This investigation showed that there was no significant difference between the agents but that the effect of the pH was significant. The uptake of fluoride in the form of fluorapatite was more than five times larger at the lower pH level. The second part of the paper deals with the rate of fluoride uptake (increase in fluoride content) from dentifrices in the same pH range. It was shown that the three agents gave the same initial rate of fluoride uptake (about 50 parts/10(6)/min) at pH 6 and that the rate of fluoride uptake in the outer layer of the enamel was proportional to the hydrogen ion activity. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Determination of inorganic pyrophosphatase in rat odontoblast layer by a radiochemical method.? [/INST] The enzyme inorganic pyrophosphatase (PPiase, EC 3.6.1.1) from the odontoblastic layer of rat incisors has been studied by means of a radiochemical micromethod. The enzyme was incubated with 32P-pyrophosphate in tris-HCl buffer at 37 degrees C. The reaction was linear with time for at least 45 min, and the pH optimum was found to be 8.8, independent of the amount of pyrophosphate present. Heating the enzyme at 56 degrees C inhibited the enzyme activity rapidly, Mg2+ ions activated the enzyme by 15% at an ion concentration of 4 mM, while higher concentrations were inhibitory. Ca2+ ions and PO43-ions inhibited the enzyme at all concentrations. F- ions did not affect the PPiase at concentrations below 8 mM, whereas higher concentrations had an inhibiting effect. Urea was found to inhibit the enzyme at concentrations above 1.5 M, while EDTA was a strong inhibitor at very low concentrations. The characteristics of PPiase agree well with the properties of the enzyme nonspecific alkaline phosphatase (EC 3.1.3.1.) studied earlier. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Assessment of denture plaque pH in subjects with and without denture stomatitis.? [/INST] To evaluate the "resting" pH and induced pH changes in denture plaque, soft deposits were collected from the fitting surface of the denture, pooled and suspended in water. Plaque pH was determined with microelectrode equipment before and after mouth rinsing with a sucrose solution. A characteristic level in the "resting" pH of denture plaque was found in most of 12 subjects tested. pH values below the baseline level were recorded for more than 2 h after a rinse. The pH depressions were more pronounced in maxillary than in mandibular plaque. Further, the pH minima tended to be lower in subjects with denture stomatitis than in controls. No clear relationship could be established between the "resting" pH and the concentration of Candida hyphae in denture smears or palatal inflammation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Bioluminescence assay of enzymes obtained from buccal epithelium by superficial scraping.? [/INST] A method is presented for the simultaneous assay of buccal enzymes by measuring reduced nicotinamide adenine dinucleotide and adenosine triphosphate with the aid of the bioluminescence of luciferase extracts. The activity of glucose-6-phosphate dehydrogenase (G6PDH) was shown earlier to be increased in homogeneous leukoplakias of the oral mucosa. Since smoking has been implicated as an etiologic factor of leukoplakia, G6PDH was measured in the normal buccal epithelium of cigarette smokers. No difference was found in the activity of G6PDH between smokers and nonsmokers when related to the activity of pyruvate kinase, which is known to be invariable in healthy and leukoplakic oral mucosa. A new compact kinetic luminescence analyzer is briefly described. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Allogeneic marrow transplantation for the treatment of leukaemia. A review.? [/INST] 22 HL-A antigen and mixed leukocyte culture-matched sibling bone marrow transplants were attempted in patients with acute leukaemia (at the National Cancer Institute) to define the toxicities of four different immunosuppressive regimens, the complications associated with warrow engraftment and antileukaemic effect. 73% (16/22) were engrafted as indicated by a change to donor red blood cells (RBC) type, leukocyte, immunoglobulin allotype or by the speed of morrow repopulation and the occurrence of the Graft Versus Host Disease (GVHD). 12 of 16 (75%) successful engrafted patients developed GVHD. The current published results of clinical bone marrow transplantation from major centers has been reviewed and will be discussed in relationship to current clinical complications associated with bone marrow transplantation. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Current status of treatment of pneumonia.? [/INST] Proper treatment of pneumonia is dependent upon a correct diagnosis. Pneumonia may be due to infectious agents, allergic phenomena, or chemical causes. Treatment regimens are outlined for the various types of pneumonia--pneumococcal, staphylococcal, fungal, and pneumonia due to gram-negative and anaerobic gram-negative bacilli, to Blastomyces dermatitidis, and to the parasite Pneumocystis carinii. In discussing current concepts of treatment, several well-known methods are emphasized, as well as newer developments, knowledge of which is essential for optimal treatment of pneumonia. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about [Clinical experiences with untreated homologous vein grafts in reconstruction of arteries (author's transl)].? [/INST] 50 transplantations of homologous vein grafts in reconstruction of arteries are reported on. Vein grafts were either transplanted immediately or used after deep freezing. This procedure has proved to be effective in the replacement of arteries during our observation period of four years. Results of homologous vein transplants are similar to those of autologous transplants. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about The effect of a simulated subarachnoid hemorrhage on cerebral blood flow in the monkey.? [/INST] The hydrogen clearance method was used to measure local and total cerebral blood flow (CBF) in the rhesus monkey before and for five hours after a simulated subarachnoid hemorrhage (SAH). CBF remained stable after SAH unless SAH was associated with a fall in cerebral perfusion pressure. In addition, cerebrovascular resistance did not increase after SAH. These results suggest that vasoactive agents in fresh whole blood, and the arterial spasm they produce when added to cerebrospinal fluid (CSF), play only a limited role in the pathogenesis of ischemic encephalopathy that follows an SAH. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Effects of oxygen saturation and pCO2 on brain uptake of glucose analogues in rabbits.? [/INST] The effect of oxygen saturation and PCO2 on brain uptake of glucose analogues was studied in rabbits. Using a modified Oldendorf technique, 14C-labeled glucose analogues with a 3H2O reference standard were introduced into the cerebral circulation via the common carotid artery, and the radioactivity of the ipsilateral cerebral cortex was counted and expressed in terms of a brain uptake index (BUI). Severe hypoxia (oxygen saturation less than or equal to 18%) resulted in approximately a 40% decrease in the BUI of 2-deoxy-D-glucose and a 45% decrease in the BUI of 3-0-methyl-D-glucose. Severe hypercapnia (PCO2 = 100 mm Hg) caused a 45% decrease in the BUI of both of these glucose analogues. Hypercapnia superimposed on severe hypoxia had no additional effect. Hypocapnia (PCO2 = 15 mm Hg) increased the BUI of 3-0-methyl-D-glucose by 35% of the control value, and this increase was extremely sensitive to competitive inhibition. When BUI values were plotted against pH rather than PCO2 for the same experiments, there was a good correlation with the calculated linear regression. These results are compared with previous findings on pathologically induced changes in brain uptake of glucose analogues, and the possible role of blood flow is considered in detail. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Lactate and pyruvate concentrations, and acid-base balance of cerebrospinal fluid in experimentally induced intracerebral and subarachnoid hemorrhage in dogs.? [/INST] The effect of blood injected into either subarachnoid space or subcortical brain tissue upon lactate and pyruvate concentrations as well as acid-base balance of cerebrospinal fluid (CSF) was studied in the anesthetized dog. CSF lactate and lactate/pyruvate ratio (L/P ratio) increased progressively following the intracranial injection of blood and reached the maximum level at six hours after injection. These changes were significantly greater in animals with intracerebral hematoma than in those with subarachnoid hemorrhage (SAH). An increase in CSF lactate and L/P ratio in hemorrhagic CSF seems to be caused by two different factors. Shed blood cells per se produce lactate and pyruvate, and blood in the subarachnoid space and intracerebral hematomas cause secondary changes in brain tissue metabolism by a probable reduction of cerebral blood flow. Therefore, an increase in CSF lactate with a concomitant rise in CSF L/P ratio is a useful indicator for brain tissue hypoxia, even when CSF is hemorrhagic. The association of an increase in CSF lactate to a disproportionate decrease in CSF HCO-3 was also observed in these animals. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about A study of variables affecting the quality of platelets stored at "room temperature".? [/INST] The effect of variables associated with the donor and with methods of collecting, processing, and storing platelets on the quality of platelets kept at ambient temperature was studied. Changes in structural integrity of platelets, decrease in pH, loss of aggregability, and kinetics in vivo of platelets tagged with 51Cr were used as indicators of the tolerance of platelets to storage. A platelet concentration of less than 2.5 x 10(6) per cu mm, a temperature of storage less than 24 C, and continuous, gentle, agitation were found to be essential for satisfactory preservation of platelet integrity, function, and post-transfusion survival. Platelets from female donors tolerated storage less well than did platelets from male donors, possibly because the lower hematocrit of blood collection from females resulted in greater initial acidity of the concentrate. A number of other variables analyzed appear to be of little or no consequence for successful platelet storage. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Dopamine-containing neurons of the substantia nigra and their terminals in the neostriatum.? [/INST] Tne ultrastructural and fluorescence histochemical characteristics of the mature rabbit substantia nigra and neostriatum have been reviewed as a frame of reference for the developmental study. Biochemical investigations were reported on neostriatal dopamine concentrations and the relative uptake and accumulation of 3H-dopamine by this tissue from fetal to adult stages, to provide quantitative data for correlation with the fluorexcence information. The development of the neurons of the substantia nigra and their axons which project to the neostriatum has been presented from their appearance at day 14 of gestation to their maturation in early postnatal life. The initial bipolar neuroblasts, which develop in the midline of the caudal mesencephalon, are fluorescent as soon as they emerge from the ependymal zone. Their fluorescent axons, which form the nigroneostriatal pathway, reach the telencephalon at day 16 of gestation and ramify extensively in the putamen by day 20, but do not enter the caudate nucleus until several days later. Some of the early fluorescent axonal profiles in the putamen are extremely large. Electron microscopic study of theis stage suggests that the large fluorescent profiles may correspond to axonal growth cones or early synapses. A distinct substantia nigra, pars compacta and reticulata, can be recognized by fluorescence microscopy by day 20 of gestation. Electron microscopy reveals that the young neurons are multipolar with numerous developing dendrites, some of which exhibit early synaptic junctions. The subsequent maturaition of these cells and the neuropil is described. The fluorescent axons of the substantia nigra grow into the putamen and caudate nucleus in a nonuniform manner forming fluorescent islands throughout the neostriatum in late fetal life. Occasionally, minute beaded fluorescent axons are found. These profiles might correspond to some of the axons with varicosities "en passage" revealed by electron microscopy. In an attempt to identify further the dopamine-containing axon, the ultratructure of adult neostriatum incubated in 5-hydroxydopamine was reported. Axonal varicosities "en passage" containing a dense "tag" in the vesicles were found. Most of the tagged boutons did not exhibit synaptic contacts. The possible significance of these finding s as related to dopamine secretion are discussed. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Amylase of the thermophilic actinomycete Thermomonospora vulgaris.? [/INST] alpha-Amylase of the thermophilic actinomycete Thermomonospora vulgaris was partially purified. Maximal enzyme activity was obtained at 60degreeC and pH 6.0. KM value was l.4%. The effect of some metal salts on enzyme activity was studied. Enzyme activity was inhibited by by KCN, EDTA, and iodoacetate. Inhibition by EDTA was completely nullified by CaCl2, but the inhibition by iodoacetate was not overcome by 2-mercaptoethanol. Exposure of the enzyme to pH 7.0 and 9.0 for 2 hr. did not affect the enzyme, but exposure to pH 3.0 for few minutes completely inactivated the enzyme. Exposure of the enzyme to 60degreeC resulted in an appreciable inactivation and exposure to 80degreeC completely inactivated the enzyme. Addition of CaCl2, 2-mercaptoethanol, or enzyme substrate the 60degreeC exposed enzyme. However, bovine serym albumin had a protective effect when the enzyme was exposed to 60degreeC but not to 80degreeC. The enzyme was stable in the presence of 8 M urea. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Simultaneous determination of 5'-nucleotidase and alkaline phosphatase activities in serum.? [/INST] A simple method is described for the simultaneous determination of alkaline phosphatase (EC 3.1.3.1) and 5'-nucleotidase (EC 3.1.3.5) in serum. The method is based on the determination of inorganic phosphorus released by the action of the two enzymes on adenosine-5'-monophosphate at pH 9.5 (200 mmol/l tris-buffer) in the presence and absence of L-cysteine. This amino acid at a concentration of 2--10 mmol/l was found to be a specific inhibitor for alkaline phosphatase but with no effect on 5'-nucleotidase activity. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Absorption of short and medium chain fatty acids in the jejunum of the rat.? [/INST] The uptake of the shortest six fatty acids (acetic to octanoic) was studied in vitro, using everted segments of rat jejunum. The marked influence of medium-pH and fatty acid chain-length suggests that non-ionic diffusion through the lipoid membrane is quantitatively the most important way of transport, but ionic diffusion through the membrane as well as transport through hydrophilic pores also seem to play a role. Though fatt acids evidently are accumulated in the tissue-fluid, and saturation kinetics, competitive inhibition and sodium- as well as energy-dependence apparently are observed, the transport mechanism is assumed to involve solely passive diffusion, - the concept of a carrier-mediated transport for short and medium chain fatty acids seems improbable. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Carcinogenic N-nitro-dimethylamine from the reaction of the analgesic amidopyrine and nitrite extracted from foodstuffs.? [/INST] The reaction of the analgesic amidopyrine (100 mg) with nitrite extracted from cured meats and from spinach in varying degrees of spoilage was studied. Unde physiological conditions the carcinogenic dimethylnitrosamine was formed at milligram levels at nitrite concentrations as low as 4 mg (in 175 ml extracted from 100 g boiled ham). The rate of decrease in concentration in the human stomach after ingestion of amidopyrine and of nitrite contained in boiled ham or in a broth from boiled ham was also measured. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Chemical relaxation studies on the system liver alcohol dehydrogenase, NADH and imidazole.? [/INST] Several years ago, Theorell and Czerlinski conducted experiments on the system of horse liver alcohol dehydrogenase, reduced nicotinamide adenine dinucleotide and imidazole, using the first version of the temperature jump apparatus with detection of changes in fluorescence. These early experiments were repeated with improved instrumentation and confirmed the early experiments in general terms. However, the improved detection system allowed to measure a slight concentration dependence of the relaxation time of around 3 ms. Furthermore, the chemical relaxation time was smaller than the one determined earlier (by factor 2). The data were evaluated much more rigorously than before, allowing an appropriate interpretation of the results. The observed relaxation time is largely due to rate constants in an interconversion of ternary complexes, which are faster than three (of the four) dissociation rate constants, determined previously by Theorell and McKinley-McKee.1,2 This fact contributed to earlier difficulties of finding any concentration dependence. However, the binding of imidazole to the binary enzyme-coenzyme complex can be made to couple kinetically into the interconversion rate of the two ternary complexes. The observed signal derives largely from the ternary complex(es). A substantial fluorescence signal change is associated with the observed relaxation process, suggesting a relocation of the imidazole in reference to the nicotinamide moiety of the bound coenzyme. Nine models are considered with two types of coupling of pre-equilibria (none-all). Quantitative evaluations favor the model with two ternary complexes connected by an interconversion outside the four-step (bimolecular) cycle. The ternary complex outside the cycle has much higher fluorescence yield than the one inside. The interconversion equilibrium is near unity for imidazole. If it would be shifted very much to the side of the "dead-end" complex (as in isobutyramide?!), stimulating action could not take place. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Comparative study of virological infections in asthmatic and nonasthmatic children.? [/INST] The author shows complex analyses: clinical, laboratory, X-rays, bronchoscopical, bronchographical and measuring lung function tests as well as the serological examinations in blood serum of both groups of asthmatic and nonasthmatic children with virological infection. The calculation of statistically significant differences between the various diagnostical results of both groups has confirmed that in asthmatic children virological infection of the respiratory tract, pathological findings in X-ray and lung function tests, bronchiectasis and secondary bacteriological invasion occurs statistically significantly more often than in nonasthmatic children. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Multiple forms of staphylococcal alpha-toxin.? [/INST] A group of proteins was readily extracted at neutrality from trichloroacetic acid precipitates of staphylococcal culture filtrate supernatants, while alpha-toxin was dissolved and activated by treating the precipitate with 8 M urea, with acidic buffers or by heating to 90-100 degrees C at neutrality. Heat activation of the precipitate produced a relatively pure alpha-toxin with a molecular weight of 39,000. alpha-Toxin was eluted together with three other proteins on hydroxyl apatite chromatography, and evidence was obtained for an association between the four proteins. On isoelectric focusing a haemolytic fraction was obtained at pH 6.2, probably due to acid activation of the precipitate formed at the cathodic end of the column. The alpha-haemolytic fractions with pI's of 7.4 and 8.6 were shown to consist of alpha-toxin only when analyzed by acrylamide electrophoresis in the presence of sodium dodecyl sulphate. The haemolytic component with a pI of 9.2 contained two additional components of molecular weights of 27,500 and 18,000. Chromatography of this material on Sephadex G-200 showed that alpha-toxin and the two proteins appeared as a high molecular complex. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Acute otitis media. A clinical bacteriological and serological study of children with frequent episodes of acute otitis media.? [/INST] A series of episodes of acute otitis media was studied with reference to bacterial findings and specific serological responses in 48 children with histories of frequent episodes before. D. pneumoniae and H. influenzae were the most frequently isolated pathogens. Re-isolations after therapy were often made in episodes with slow healing or therapeutic failure. Most children harboured pathogens in nasopharynx even when they had no signs of respiratory tract infections. Homologous relapses were seen only in few cases and never with pneumococcus type 3 and only once with H. influenzae type b. Specific serological responses were demonstrable generally in children over 2 years of age. D. pneumococcus type 3 and H. influenzae type b generally provoked antibody response. No levels indicating immunoglobulin deficiencies could be found in the children. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Endosymbiosis and cellular tolerance in the Hawaiian soft coral Sarcothelia edmondsoni verrill.? [/INST] The relationship between the soft coral Sarcothelia edmondsoni Verrill and its symbiotic algae is considered as an early instance of cellular tolerance which can be disturbed by a variety of adverse conditions. The algal cells lie in vesicles deep within the endodermal cells of the host and are not subject to digestion. Their expulsion appears to be a reverse translocation to the distal end of the host cell and escape by a form of reversed phagocytosis resembling secretion. The cellular mechanisms involved are not clear. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Epidemiologic investigations of the 1969 epidemic of Venezuelan encephalitis in Ecuador.? [/INST] An epizoodemic of Venezuelan equine encephalitis (VEE), subtype I variant B, occurred in Ecuador during the rainy and hot season of 1969. In this paper, a general description of the epidemic is given and virus isolations from humans are reported. A serologic survey was performed in order to determine the extension of the epidemic along the coastal zone of the country. It is not clear whether the higher antibody rate in older people was because they were at greater risk of infection or was the result of an accumulated immunity with time. The latter could be an indication of endemic virus activity, not yet proven for the VEE IB virus variant. Mosquito surveillance and attempted control by aerial spraying were carried out. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Congenital malformations of the central nervous system produced by narcotic analgesics in the hamster.? [/INST] Maternal dose--fetal teratogenic response data were obtained for a variety of narcotic and related compounds by single subcutaneous injections of the drugs into pregnant hamsters during the critical periods of central nervous system organogenesis. The number of abnormal fetuses from females injected with diacetylmorphine (heroin), thebaine, phenazocine, pentazocine, propoxyphene, and methadone increased as the maternal dose of the compounds was increased. By contrast, morphine, hydromorphone, and meperidine produced an increase in the number (per cent) of fetal anomalies only up to a certain maternal dose level. Further increases in maternal dose levels did not produce additional fetal anomalies. Comparative studies of single and multiple maternal doses indicated that diacetylmorphine (heroin) and methadone produced a four- to sixfold increase in fetal anomalies with repetitive doses whereas the percentage of malformed fetuses remained the same with hydromorphone (Dilaudid). The narcotic antagonists nalorphine, naloxone, levallophan, and cyclazocine blocked the teratogenic effects of both single and multiple doses of the narcotics. </s>

<s>[INST] <<SYS>> You are a very helpful assistant who provides accurate and concise responses. <</SYS>> can you explain about Evaluation of a non-professional visual screening method.? [/INST] A screening method designed for administration by lay personnel is evaluated and compared to Modified Clinical Technique screening results for a screening of 1600 elementary school children. </s>