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Role of acetate metabolism in sporulation of Saccharomyces carlsbergensis.
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Several aspects of the role of acetate metabolism in the sporulation of Saccaromyces carlsbergensis were investigated. Experiments in which the development of the respiratory system was either stimulated by growth on sugars to which the cells have to adapt, or inhibited by chloramphenicol suggested a correlation between respiratory development and sporulation. In cells in which the respiratory system has been repressed during growth, mitobhondrial protein synthesis and derepression are prerequisites for sporulation. When derepression is complete, sporulation no longer depends on mitochondrial protein synthesis. Incorporation experiments with acetate showed that this compound is an important source of intermediates for biosynthetic processes that occur during sporulation. Its incorporation into macromolecular fractions is tightly coupled to sporutlation.
| 2,101
|
The influence of physicochemical factors on the thermal inactivation of murine interferon.
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The degradation of biological activity of virus-induced murine interferon was determined in linear nonisothermal and multiple isothermal tests. The stabilizing effect of pH during heating on interferon in solution was greatest at low pH, such that pH 2 greater than pH 5 greater than pH 7 greater than or equal to pH 9; freeze-dried preparations of interferon were also more heat-stable at acid pH than at neutral pH. Heat stability was a function of the H+-ion concentration rather than the ionic composition of the buffer; interferon solutions containing monovalent cations with different ionic radii had similar heat stability. A change in the H+ ion concentration was a critical event during the cooling of heated interferon: a shift in the direction of acidity contributed to stability whereas a shift towards alkalinity led to inactivation. The rate of cooling of heated interferon significantly influenced its residual activity. Rapid cooling and sudden freezing decreased the residual activities of interferons at pH 2 and 9 more than "normal" cooling, an effect not observed at pH 7. Interferon heated to 80degree C could not be reactivated at 40degree C or 55degree C. Interferon of higher apparent molecular weight was more heat-stable than that with lower apparent molecular weight. It is postulated that the physicochemical alterations in the aqueous environment significantly affecting the stability of interferon operate by producing changes in the size and/or conformation of interferon molecules. A model is proposed that relates thermal inactivation to different possible molecular states of interferon.
| 2,143
|
Factors regulating amino acid release from extrasplanchnic tissues in the rat. Interactions of alanine and glutamine.
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1. Factors regulating the release of alanine and glutamine in vivo were investigated in starved rats by removing the liver from the circulation and monitoring blood metabolite changes for 30 min. 2. Alanine and glutamine were the predominant amino acids released into the circulation in this preparation. 3. Dichloroacetate, an activator of pyruvate dehydrogenase, inhibited net alanine release: it also interfered with the metabolism of the branched-chain amino acids valine, leucine and isoleucine. 4. L-Cycloserine, an inhibitor of alanine aminotransferase, decreased alanine accumulation by 80% after functional hepatectomy, whereas methionine sulphoximine, an inhibitor of glutamine synthetase, decreased glutamine accumulation by the same amount. 5. It was concluded that: (a) the alanine aminotransferase and the glutamine synthetase pathways respectively were responsible for 80% of the alanine and glutamine released into the circulation by the extrasplanchnic tissues, and extrahepatic proteolysis could account for a maximum of 20%; (b) alanine formation by the peripheral tissues was dependent on availability of pyruvate and not of glutamate; (c) glutamate availability could influence glutamine formation subject, possibly, to renal control.
| 2,155
|
Fructose 1,6-diphosphate aldolase from rabbit muscle. Effect of pH on the rate of formation and on the equilibrium concentration of the carbanion intermediate.
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The rate of oxidation of ferricyanide of the aldolase-dihydroxyacetone phosphate complex was measured under different conditions. The following conclusions are drawn. 1. In the cleavage of fructose diphosphate, catalysed by native aldolase, the steady-state concentration of the enzyme-dihydroxyacetone phosphate carbanion intermediate represents less than 6% of the total enzyme-substrate intermediates. 2. Fructose diphosphate and dihydroxyacetone phosphate compete for the four catalytic sites on aldolase, the binding of fructose diphosphate being about twice as tight. 3. The equilibrium concentration of the carbanion intermediate formed by reaction of carboxypeptidase-treated aldolase with dihydroxyacetone phosphate is independent of pH between 5.0 and 9.0. The rates of fromation of the carbanion intermediate and of the reverse reaction are, however, concomitantly increased by increasing pH between 5.0 and 6.5.
| 2,160
|
Purification and properties of the thermostable acid protease of Penicillium duponti.
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An acid protease produced by the thermophilic fungus Penicillium duponti K 1014 has been purified by consecutive ion-exchange and gel permeation chromatography, and crystallized from aqueous acetone solution. The purified endopeptidase gave a symmetrical schlieren peak by sedimentation velocity, and was found to be homogeneous upon disc gel electrophoresis at pH 9.5. The enzyme was most active at pH 2.5 against milk casein and showed high thermostability. An isoelectric point of 3.81 was found by isoelectric focusing. A minimum molecular weight of 41 590 was calculated from the amino acid composition, adopting an arginine content of one residue per mole of enzyme. This minimum molecular weight is in good agreement with the value of 41 000 previously found by gel permeation (Hashimoto, H., Iwaasa, T., and Yokotsuka, T. (1973), Appl. Microbiol. 25, 578). Besides the thermostability, the purified P. duponti protease differs from other well-characterized acid proteases in that it contains carbohydrate, 4.33% expressed as glucose. The enzyme was not affected by p-bromophenacyl bromide, but was completely inactivated by alpha-diazo-p-bromoacetophenone, diazoacetyl-DL-norleucine methyl ester, and diazoacetylglycine ethyl ester, in the presence of Cu2+. The complete inactivation of the protease by diazoacetyl-DL-norleucine methyl ester resulted in the specific incorporation of 1 mol of norleucine/mol of enzyme. On the basis of similar behavior of other acid proteases toward this inactivator, the results suggest the presence at the active site of an unusually reactive carboxyl group, involved in the catalytic function. The naturally occurring pepsin inhibitor of Streptomyces naniwaensis [Murao, S., and Satoi, S. (1970), Agric. Biol. Chem. 34, 1265] inhibited also the protease, at a threefold molar excess with respect to the enzyme.
| 2,287
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Avoidance of strongly chaotropic eluents for immunoaffinity chromatography by chemical modification of immobilized ligand.
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The need for chaotropic eluents in immunoaffinity chromatography is a consequence of the high affinities of antibodies towards their antigens. This affinity is decreased and elution of antiglucagon antibodies from a column of immobilized glucagon can be achieved under mild conditions when the steric complementarity to the antibody binding site is perturbed by selective chemical modification of the hormone. The effects of reaction with 2-hydroxy-5-nitrobenzyl bromide, tetranitromethane and hydrogen peroxide have been studied. Conversely, treatment of immobilized antibodies with 2-hydroxy-5-nitrobenzyl bromide facilitates the elution of glucagon during immunoaffinity chromatography. The general implications of these results are discussed.
| 2,298
|
Purification and some properties of rat liver cysteine oxidase (cysteine dioxygenase).
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Cysteine oxidase (cysteine dioxygenase, EC 1.13.11.20) was purified approximately 1000-fold from rat liver. The purified enzyme (protein-B) was obtained as an inactive form, which was activated by anaerobic preincubation with L-cysteine. The active form of protein-B was inactivated during aerobic incubation to produce cysteine sulfinate. This inactivation of protein-B was protected by a distinct protein in rat liver cytoplasm, namely stabilizing protein (protein-A). The Ka and Km values for L-cysteine were 0.8-10(-3) M and 1.3-10(-3) M respectively. The enzyme was strongly inhibited by Cu+ and/or Fe2+ chelating agents but not by Cu2+ chelating agent. The optimum pH of enzyme reaction was 8.5-9.5 while that of enzyme activation was 6.8-9.5, with a broad peak.
| 2,307
|
Separation of subchloroplast membrane particles by counter-current distribution.
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Counter-current distribution in an aqueous Dextran-polyethylene glycol two-phase system has been used to fractionate membrane fragments obtained by press treatment of Class II chloroplasts. By the counter-current distribution technique membrane particles are separated according to their surface properties such as charge and hydrophobicity. The fractions obtained were analysed with respect to photochemical activities, chlorophyll and P-700 contents. The Photosystem II enrichment after counter-current distribution was better than that obtained by differential centrifugation of the disrupted chloroplasts. However, the best separation of Photosystem I and II enriched particles could be achieved if differential centrifugation was combined with the counter-current distribution technique. Each centrifugal fraction could be further separated into Photosystems I and II enriched fractions since the Photosystem II particles preferred the dextran-rich bottom phase while the Photosystem I particles preferred the polyethylene glycol-rich top phase. By this procedure it was possible, without the use of detergents, to obtain vesicles which were more enriched in Photosystem II as compared to intact grana stacks. The partition behaviour of undisrupted Class II chloroplasts and the Photosystem I centrifugal fraction was the same. This similarity indicated that the membrane which is exposed to the surrounding polymers by the Class II chloroplasts is the Photosystem I rich membrane of the stroma lamellae.
| 2,312
|
Relations between the electrical potential, pH gradient, proton flux and phosphorylation in the photosynthetic membrane.
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The transmembrane electrical potential (deltaphi), the proton flux (H+), the rate of electron transport (e), the pH gradient (deltapH) and the rate of phosphorylation (ATP) were measured in chloroplasts of spinach. Photosynthesis was excited periodically with flashes of variable frequencies and intensities. A new method is described for determining the rate of electron transport and proton flux. Under conditions where the rate of electron transport and proton flux are not pH controlled the following correlations were found in the range 50 mV less than or equal to deltaphi less than or equal to 125 mV and 1.8 less than or equal to deltapH less than or equal to 2.7: (1) The pH gradient, deltapH, increases with H+ independently of Phout between 7-9. (2) The rate of phosphorylation, ATP, depends exponentially on deltapH (at constant deltaphi) and is independent of pHout between 7-9. (3) The rate of phosphorylation, ATP, depends also on deltaphi (at constant deltapH and at constant proton flux H+). (4) The proton flux via the ATPase pathway, Hp+, depends non-linearly on the ratio of the proton concentrations: Hp+ approximately (Hin+/Hout+)b, (b=2.3--2.6). The proton flux via the basal pathway, Hb+, depends linearly on the ratio of the proton concentrations: Hb+ approximately (Hin/Hout). (5) The ratio deltaH+/ATP (e/ATP, i.e. the ratio of the total proton flux, Hp+ + Hb+, and the rate of ATP formation, ATP, depends strongly on deltaphi and on deltapH. The ratio is deltaH+/ATP approximately 3 (e/ATP approximately 1.5) at deltapH 2.7 and deltaphi = 125 mV. (6) It is supposed that the reason for the dependence of deltaH+/ATP on deltaphi anddeltapH is the different functional dependence of the basal proton flux Hb+ and the phosphorylating proton flux Hp+ on deltapH and deltaphi. The calculation of deltaH+/ATP on the basis of this assumption is in fair agreement with the experimental values. Also the "threshold" effects can be explained in this way. (7) The ratio of deltaHp+/ATP, i.e. the ratio of the phosphorylating proton flux Hp+ and ATP, is deltaHp+/ATP APPROXIMATELY 2.4.
| 2,316
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Primary reactions of photosystem II at low pH. I. Prompt and delayed fluorescence.
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Prompt and delayed chlorophyll fluorescence have been studied in broken spinach chloroplasts at pH values down to 2.6. No direct effect of low pH on the primary charge separation in Photosystem II was observed. The irreversible inactivation of a secondary electron donor in a narrow pH range around pH 4.5 was demonstrated. At lower pH values the photooxidized form of a more primary electron donor, revealed by its efficient fluorescence quenching, was reduced with a half time of about 200 mus, 25% by another electron donor and 75% by back reaction with the reduced acceptor. The electron donation had a half time of 800 mus and was practically irreversible. The back reaction had a pH dependent half time: about 270 mus at pH 4 and increasing towards lower pH. The competition of both reactions resulted in a net efficiency of the charge separation at pH 4 of 25%, increasing towards lower pH.
| 2,318
|
The rate of calcium uptake into sarcoplasmic reticulum of cardiac muscle and skeletal muscle. Effects of cyclic AMP-dependent protein kinase and phosphorylase b kinase.
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Calcium transport into sarcoplasmic reticulum fragments isolated from dog cardiac and mixed skeletal muscle (quadriceps) and from mixed fast (tibialis), pure fast (caudofemoralis) and pure slow (soleus) skeletal muscles from the cat was studied. Cyclic AMP-dependent protein kinase and phosphorylase b kinase stimulated the rate of calcium transport although some variability was observed. A specific protein kinase inhibitor prevented the effect of protein kinase but not of phosphorylase b kinase. The addition of cyclic AMP to the sarcoplasmic reticulum preparations in the absence of protein kinase had only a slight stimulatory effect despite the presence of endogenous protein kinase. Cyclic AMP-dependent protein kinase catalyzed the phosphorylation of several components present in the sarcoplasmic reticulum fragments; a 19000 to 21 000 dalton peak was phosphorylated with high specific activity in sarcoplasmic reticulum preparations isolated from heart and from slow skeletal muscle, but not from fast skeletal muscle. Phosphorylase b kinase phosphorylated a peak of molecular weight 95000 in all of the preparations. Cyclic AMP-dependent protein kinase-stimulated phosphorylation was optimum at pH 6.8; phosphorylase b kinase phosphorylation had a biphasic curve in cardiac and slow skeletal muscle with optima at pH 6.8 and 8.0. The addition of exogenous phosphorylase b kinase or protein kinase increased the endogenous level of phosphorylation 25-100%. All sarcoplasmic reticulum preparations contained varying amounts of adenylate cyclase, phosphorylase b and a (b:a = 30.1), "debrancher" enzyme and glycogen (0.3 mg/mg protein), as well as varying amounts of protein kinase and phosphorylase b kinase which were responsible for a significant endogenous phosphorylation. Thus, the two phosphorylating enzymes stimulated calcium uptake in the sarcoplasmic reticulum of a variety of muscles possessing different physiologic characteristics and different responses to drugs. In addition, the phosphorylation catalyzed by these enzymes occurred at two different protein moieties which make physiologic interpretation of the role of phosphorylation difficult. While the role phosphorylation in these mechanisms is complex, the presence of a glycogenolytic enzyme system may be an important link in this phenomenon. The sarcoplasmic reticulum represents a new substrate for phosphorylase b kinase.
| 2,325
|
[Effect of IAA on the photophosphorylation of pea isolated chloroplasts].
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Effect of IAA (10(-10)-10(-3) M) on photophosphorylation, NADP reduction and the oxygen exchange is investigated. It is shown that low concentrations of IAA (10(-10)-10(-7) M) increase the photophosphorylation reaction and the flow of electrones to NADP under the phosphorylation conditions in the chloroplasts, and their effect on the O2 exchange is not the same in different types of photophosphorylation. It is supposed that the effect of IAA on the photophosphorylation is connected with H292 metabolism in chloroplasts and with catalase and peroxidase functions.
| 2,332
|
[Study of the osmotic behaviour of human platelets].
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Observation of the behaviour of platelets in hypotonic media affords an approach to the evaluation of their fragility. It should be possible to apply such a test to various fields such as the study of rheological properties of platelets, the investigation of certain pathological cases and eventual alterations during storage. The curve obtained reflects a continuous distribution of platelet osmotic fragility.
| 2,344
|
[Rapid production of a biotin deficiency in mice].
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This work describes a rapid method for the production of a biotin-deficiency in mice. Besides classical morphological symptoms, a decrease of activities of some biotin-dependent enzymes was also observed. The biotin-enzymes are not inhibited at the same extent in a same organ and the metabolic changes do not always follow the enzymatic modifications.
| 2,375
|
Studies on fazadinium bromide (ah 8165): a new non-depolarizing neuromuscular blocking agent.
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Intravenous dose-response relationships were used to correlate neuromuscular paralysis with the effects of fazadinium (AH 8165) on autonomic mechanisms in anaesthetized cats and rhesus monkeys and with cardiovascular effects in man. In cats and monkeys neuromuscular paralysis of the twitch responses of the gastrocnemius muscle by fazadinium was accompanied by impairment of the vagally induced bradycardia, but cardiovascular disturbances were small. Blockade of sympathetic mechanisms and hypotension were only evident with supra-maximal doses. In man tachycardia was a common occurrence and in some patients hypertension occurred with doses of the drug needed for complete neuromuscular paralysis. Fazadinium was three to four times more potent in rhesus monkeys than in cats and its course of action was considerably longer. The potency of the drug in man corresponded more closely to that in cats than in rhesus monkeys but its course of action in patients was similar to that in monkeys. In man, dose-response curves were constructed for the contractions of the adductor pollicis muscles elicited by tetanic and single twitch stimuli applied to the corresponding ulnar nerves. The onset of paralysis of the tetanic contractions after the intravenous injection of fazadinium (0.4 mg/kg) occurred within two minutes, but recovery was slow and about 50 minutes were needed for its completion. Depression of the simultaneously recorded twitch responses was less marked, slower in onset and recovery was slightly more rapid. These effects were similar to those obtained with tubocurarine (0.2 mg/kg) but the action of fazadinium was slightly shorter. Tetanic-tension ratios were computed after 30 and 50 per cent recovery from neruomuscular blockade in man. These ratios were lower with fazadinium than with tubocurarine and indicated taht tetanic fade was greater and more persistent after fazadinium than after tubocurarine.
| 2,378
|
Laboratory aids to diagnosis--enzymes.
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A summary is presented of those organ specific enzyme assays traditionally used in evaluation of the patient with cancer. In addition, the use of certain serum enzymes such as gamma-glutamyl transpeptidase, phosphohexose isomerase or 5'-nucleotidase as aids in following the course of the disease, particularly in patients with metastatic spread to the liver is outlined. Also considered is the utility of enzyme analysis in biopsy tissue, biologic fluids, and washings of body cavities. Newer enzymes are considered which might, in the future, be developed as diagnostic tools or as probes for the understanding of the etiology of cancer.
| 2,380
|
Failure to monoaminergic and cholinergic receptor blockers to prevent prostaglandin E2-induced luteinizing hormone release.
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Receptor blocking drugs were used to determine whether adrenergic, dopaminergic, serotoninergic, or cholinergic synapses are involved in mediating the LH release induced by intraventricularly injected PGE2. Prostaglandin E2 (5mug) was injected into the 3rd ventricle (3rd V) of ovariectomized rats, and plasma LH concentrations before and after treatment were determined by radioimmunoassay. Phentolamine, 20 or 30 mug, or pronethalol, 20 mug (alpha and beta adrenergic receptor blockers, respectively) injected into the 3rd V failed to alter the elevation of plasma LH evoked by PGE2 injected into the ventricle 10 min later. Likewise, LH release following PGE2 was not changed when a dopaminergic blocker, pimozide (0.63 mg/kg, SC), was injected 2 h prior to PGE2. Two antagonists of serotonin, methysergide maleate (3 mg/kg ip) or cinanserin HC1 (1 mg/kg iv) given 2 h or 45 min before PGE2, respectively, failed to alter the action of PGE2. Atropine (100 or 250 mug) injected into the 3rd V 10 min prior to PGE2 was also ineffective in blocking the increase in plasma LH following PGE2. The results of this study indicate that the effect of PGE2 on LH release is not mediated by adrenergic, dopaminergic, serotoninergic, or cholinergic receptors. They also suggest that PGE2 is not acting trans-synaptically but probably directly on the LHRH neuron to induce the discharge of LHRH into the hypophysial portal vessels which then evokes release of LH from the adenohypophysis.
| 2,457
|
Influence of unsaturated fatty acids in chloroplasts. Shift of the pH optimum of electron flow and relations to deltapH, thylakoid internal pH and proton uptake.
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Linolenic acid (C18:3) is the main endogenous unsaturated fatty acid of thylakoid membrane lipids, and seems in its free form to exert significant effects on the structure and function of photosynthetic membranes. In this investigation the effect of linolenic acid was studied at various pH values on the electron flow rate in isolated spinach chloroplasts and related to deltapH, the proton pump and the pH of the inner thylakoid space (pHi). The deltapH and pHi were estimated from the extent of the fluorescence quenching of 9-aminoacridine. Linolenic acid caused a shift (approximately one unit) of the pH optimum for electron flow toward acidity in the following systems: (a) photosystems II + I (from H2O to NADP+ or to 2,6-dichlorophenolindophenol) coupled or non-coupled; (b) photosystem II (from H2O to 2,6-dichlorophenolindophenol in the presence of dibromothymoquinone). In photosystem I conditions (phenazine methosulphate), the deltapH of the control increased as a function of external pHo with a maximum around pH 8.8. When linolenic acid was added, the deltapH dropped, but its optimum was shifted toward more acidic pHo. The same phenomena were also observed in photosytems II + I (from H2O to ferricyanide) and in photosystem II conditions (from H2O to ferricyanide in the presence of dibromothymoquinone). However, the deltapH was smaller and the sensitivity of the proton gradient toward linolenic acid was eventually higher than for photosystem I electron flow activity. The proton pump which might be considered as a measure of the internal buffering capacity of thylakoids was optimum at pHo, 6.7 in the controls. An addition of linolenic acid diminished the proton pump and shifted its optimum toward higher pHo. As a consequence, pHi increased when pHo was raised. At the optimal pHo 8.6 to 9, pHi were 5 to 5.5. Additions of increasing concentrations of linolenic acid displaced the curves toward higher pHi. A decrease of pHo was therefore required to maintain the pHi in the range of 5-5.5 for maximum electron flow. In conclusion, the electron flow activity seems to be delicately controlled by the proton pump (buffer capacity), deltapH, pHi and pHo. Fatty acids damage the membrane integrity in such a way that the subtile equilibrium between the factors is disturbed.
| 2,470
|
Effects on rectal temperature in rats of gamma-aminobutyric acid; possible mediation through putative transmitters.
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The rectal temperature of male rats was measured in a thermoneutral environment (25 degrees C) and at ambient temperatures of 15 and 35 degrees C. Unless otherwise specified all drugs were administered intracerebroventricularly (i.c.v.) and all results are reported for the thermoneutral environment. Exposure to 15 degrees C did not affect the rectal temperature but exposure to 35 degrees C produced hyperthermia. At 15 and 25 degrees C, 20 mug GABA produced hyperthermia which was longer lasting at the former ambient temperature. GABA (20 mug) prevented the hyperthermic effect of exposure to 35 degrees C and produced hypothermia in animals maintained at this temperature for 1 hr. A low dose (1 mug) of NA produced hyperthermia and a higher dose (mug) hypothermia. In rats pretreated with sodium salicylate (i.p.), 20 mug GABA and 1 mug NA produced hypothermia instead of hyperthermia, suggesting the release of PGE in mediating hyperthermia. The hypothermic effect of 10 mug NA and of GABA observed at 35 degrees C was blocked by phentolamine, an indication of the possibility of alpha-adrenoceptor mediation.
| 2,482
|
Properties of glutamine aminohydrolases in subcellular fractions of liver of tumour bearing mice.
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Glutamine aminohydrolase is found to be present in microsomal and soluble supernatant in liver of EAC-bearing mice. Enzymes obtained from these two sources were characterized and found to behave differently from the mitochondrial glutaminase of both normal and tumour-bearing mice.
| 2,490
|
The alternate complement pathway in inflammatory bowel disease. Quantitation of the C3 proactivator (factor B) protein.
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A component of the complement system's alternate pathway was investigated in ulcerative colitis and Crohn's disease. The mean C3PA (Factor B) titer in normals was 74 +/- 15%; in ulcerative colitis, 92 +/- 18%; and in Crohn's disease, 119+/- 24%. Significance was at the P less than 0.001 level when the mean values for the ulcerative colitis and the Crohn's disease groups were compared to normal subjects. Titers did not change significantly with exacerbation or amelioration of the diseases or when patient groups were analyzed according to the mode of treatment received.
| 2,509
|
A histochemical study of the apparent deamination of proteins by sodium hypochlorite.
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The possible chemical mechanisms by which neutral solutions of sodium hypochlorite containing a high concentration of sodium chloride abolish the acidophilia of proteins in sections of fixed tissue are reviewed. The most probable one is the chlorination of the protein terminal amino groups, followed by the breakdown of the N-chloramine so formed into alpha-ketocarboxylic acid, nitrile or aldehyde groups. Hypochlorite solutions certainly do not deaminate tissue sections as was previously thought. Experimental evidence for the formation of relatively stable N-chloramine groups in situ and their limited conversion to aldehydes is reported. For example, the acidophilia of hypochlorite-treated sections was found to be restored after flooding them with hydriodic acid followed by the extraction of the liberated iodine with an alcohol. The significance of these experimental findings is discussed.
| 2,567
|
The possibilities and limitations of membrane methods for the histochemical demonstration of cholinesterases.
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The thiocholine method for the histochemical detection of cholinesterases according to Karnovsky-Roots was adapted for unfixed cryostat sections by addition of the agar solution to the incubation mixture and by using the semipermeable membrane interposed between the section and the incubation medium. The procedure prevents the leakage of the enzyme activity of the section and is suitable for tissues where the cholinesterase activity is low.
| 2,569
|
Collaborative study of the Food Chemicals Codex method for the determination of the neutralizing value of sodium aluminum phosphate.
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Fifteen laboratories participated in a collaborative study to evaluate the Food Chemicals Codex method for the determination of the neutralizing value of sodium aluminum phosphate. The AOAC method for determining the neutralizing value of sodium acid pyrophosphate, sec. 8.010, was also included in the study. The precisions of the Food chemicals Codex method, based on the between-replicate standard deviation and on one collaborator making one determination, are 1.16 and 3.66, respectively. The Food Chemicals Codex method for the determination of the neutralizing value of sodium aluminum phosphate has been adopted as official first action.
| 2,581
|
Inhibition by superoxide dismutase of methemoglobin formation from oxyhemoglobin.
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The formation of methemoglobin from oxyhemoglobin in a solution containing photoreduced riboflavin and oxygen was inhibited by superoxide dismutase. The rate of the reaction was pH-dependent in the range of 6.8 to 7.8, increasing as the pH was reduced. Inhibition by superoxide dismutase was enhanced as the EDTA concentration increased and was dependent on enzymatic activity. Under conditions in which superoxide dismutase inhibition was incomplete, catalase inhibited the reaction but mannitol had no effect. The data support the mediation of methemoglobin formation by superoxide. The hypothesis is offered that superoxide anion reduced the heme-bound oxygen in oxygemoglobin by one electron, permitting the subsequent dissociation of ferrihemoglobin and peroxide. The ability of superoxide dismutase to inhibit the formation of methemoglobin may represent one of its functions in the mature erythrocyte.
| 2,597
|
The fluorimetric detection of pesticides on aluminium oxide layers.
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Several pesticides have been investigated for their fluorigenic properties on acidic and basic aluminium oxide layers. Fluorescence was obtained in several instances and the relative intensities were observed. Fluorescence spectra were recorded for the best fluorescence obtained before and after heat treatment of the chromatogram. The results are compared with those already reported for silica gel layers.
| 2,611
|
A comparison of female and male neurotic depressives.
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Female and male neurotic depressives in an outpatient psychiatric clinic were compared on measures of subjective distress, interpersonal concerns, and types of treatment given. There were essentially no differences between the two groups on the patient self-report measures. However, female patients were found to have significantly more therapy sessions that the male neurotic depressives. Also, the female patients were more likely than the male patients to receive psychotropic medication, especially the more potent antidepressant variety.
| 2,620
|
Lymphoid cell fractionation by aggregated immunoglobulin-agarose columns.
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Fractionation by columns of aggregated rat immunoglobulin (Agg Ig)-agarose was investigated as a method of separating different populations of lymphoid cells. With rat spleen cells, Agg Ig columns retained phagocytes, IgM- and IgG-antibody-forming-cells, cells mediating antibody- or PHA-induced lysis of chicken erythrocytes, and specifically immune splenocytes lytic to chicken erythrocytes without exogenous antibody. Agg Ig columns did not selectively remove 'B lymphocytes' (surface-Ig-bearing lymphocytes with or without EAC' receptors), or T lymphocytes capable of PHA-induced proliferation or graft-versus-host reactivity. With mouse spleen cells, Agg Ig columns retained alloimmune cytotoxic T cells.
| 2,637
|
Detection of pneumococcal polysaccharide in the sputum of patients with pneumococcal pneumonia by counterimmunoelectrophoresis.
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Each of 41 patients with bacterial pneumonia was placed into 1 of 4 categories based on the relative clinical certainty of the diagnosis of pneumococcal pneumonia. The frequency of pneumococcal polysaccharide in the sputum by counterimmunoelectrophoresis (CIE) was then noted for each diagnostic category of patients. Detection of pneumococcal polysaccharide in sputum correlated with the diagnostic certainty of pneumococcal pneumonia, while results of culture of sputum were less indicative of pneumococcal infection. Saliva of 83 normal individuals failed to give positive tests for pneumococcal polysaccharide despite the presence of alpha-hemolytic streptococci on culture. Furthermore, the mere presence of pneumococci in cultures did not predict a positive test for polysaccharide by CIE nor did the absence of pneumococci mean that polysaccharide would not be detected. This study suggests that detection of pneumococcal polysaccharide appears more rapid, more sensitive, and more specific than sputum cultures in diagnosing pneumococcal infection of the lung.
| 2,641
|
Cerebral monoamine metabolism in guinea-pigs with ascorbic acid deficiency.
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Guinea-pigs kept on a diet deficient in vitamin C showed, after 3 weeks, a marked decrease of ascorbic acid in brain and blood leucocytes as well as of the activity of alkaline phosphatase in blood plasma. Pair-fed animals did not exhibit these changes. The alpha-methyl-p-tyrosine (alpha MpT)-induced diminution of noradrenaline in the hypothalamus and the rest of the brain was attenuated in pair-fed animals, but restored in guinea-pigs deficient in ascorbic acid. The cerebral noradrenaline content (without administration of alpha MpT) showed a decrease in both pair-fed and ascorbic acid deficient animals. The noradrenaline of the heart exhibited a similar tendency. The alpha MpT-induced dopamine decrease in the striatum of ascorbic acid deficient animals was attenuated and the dopamine content (without alpha MpT administration) decreased. Pair-fed animals showed a similar tendency. The striatal concentration of homovanillic acid (HVA) was diminished in both pair-fed and ascorbic acid deficient guinea-pigs. The cerebral content of 5-hydroxyindoleacetic acid showed a decrease in pair-fed as well as in ascorbic acid deficient animals. It is concluded that ascorbic acid deficiency enhances the turnover of brain noradrenaline, whereas under-nutrition without ascorbic acid deficiency (pair-feeding) diminishes the turnover of cerebral noradrenaline, 5-hydroxytryptamine and striatal dopamine.
| 2,659
|
A study of the human metabolism of secbutobarbitone.
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The urinary excretion of secbutobarbitone (I) and its metabolites has been studied quantitatively using combined gas chromatography-mass spectrometry. After a single oral dose was given to healthy male volunteers, unchanged drug (5-9%), 2'-hydroxysecbutobarbitone (II, 1.7-3.2%), 2'-oxosecbutobarbitone (III, less than 1%), and the carboxylic acid (IV, 24-34%) were found. The kinetics of the excretion process were studied.
| 2,664
|
[Effect of a magnetic field on Escherichia coli].
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The decontaminating effect of the pulsing magnetic field on the E. coli infected reclaimed water was studied on two installations. The magnetic field intensity was 500 and 1000-1500 ersted and the microbial load was 1, 10 and 100 thous. microbial units per 1 ml. It was found that the magnetic treatment of water had a noticeable bactericidal effect. This indicated that the method can be used for decontamination of reclaimed water.
| 2,806
|
Blood alcohol level discrimination by nonalcoholics. The role of internal and external cues.
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Men were trained to estimate their blood alcohol levels, after drinks of different strengths, by means of internal or external cues or both. All groups improved in estimation accuracy but the type of training made no difference.
| 2,811
|
Differential inhibition of sclerotial germination in Whetzelinia sclerotiorum.
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A number of diverse compounds including divalent metal ions, simple sugars, and common counterions, buffers, and fungicides were surveyed in the laboratory with regard to ability to inhibit germination of field-collected sclerotia from Whetzelinia sclerotiorum. Many compounds were inhibitory and several were comparable in effectiveness to benomyl and other commercial fungicides. Different levels of a given inhibitor were needed to prevent stipe formation, apothecial formation or mycelial germination. Inhibition was not correlated with ionic strength or related to pH.
| 2,873
|
Cobalamins in fibroblasts cultured from normal control subjects and patients with methylmalonic aciduria.
|
The intracellular content and proportional distribution of B12 (cobalamin) derivatives in fibroblasts cultured from patients with various forms of methylmalonic aciduria, as well as from normal control subjects, has been determined by a two-dimensional chromatobioautographic technique. Each line of fibroblasts was grown in the presence of four concentrations of cobalamin, ranging from the 0.04-0.07 pmol/ml contained in the basal medium to 74 pmol/ml (100 ng/ml), added in form of hydroxocobalamin (OH-CHl). Control cells grown in the basal medium contained substantial proportions of both methylcobalamin (MeCbl) and adenysylcobalamin (AdoCbl), with the former predominating. As increasing concentrations of OH-CBl were added to the growth medium, the total cellular cobalamin content increased without marked changes in the relative proportions of MeCbl, AdoCbl, and OH-Cbl. Three different patterns were discernable in the cobalamin distributions of the cells cultured from patients with methylmalonic aciduria (Table 1 and Fig. 1).
| 2,896
|
Formation and in-vivo-distribution of different 99mTc-Sn-pyrophosphate complexes.
|
The formation of two different 99mTc-Sn-pyrophosphate complexes was determined by evaluation of their in vivo distribution in rats. It was found that formation of a 2 : 2 Sn : PyP complex, which is bone seeking, is depending as well on the pyrophosphate as on the hydrogen ion concentration in the equilibrium. On the contrary, formation of a 2 : 1 Sn : PyP complex, which shows no bone affinity but concentrate in the kidneys, is hydrogen ion independent and occurs even at very low pyrophosphate concentrations. The probable structure of these complexes is discussed.
| 2,905
|
Separation of (3') deoxynucleotides with cation exchange columns.
|
A procedure is described for a one-step separation of synthetic (3') deoxynucleotides purchased commercially or those purified and isolated from the enzymatic digests of DNA. The method is simple. A 50 ml buret was used for column which was filled with the resin slurry and packed at water aspirator pressure. The compounds were eluted from the column at atmospheric pressure under gravity flow using a fraction collector and read on a Beckman DU spectrophotometer. Recoveries were in excess of 90% and no accessory devices were required. The use of a volatile buffer, e.g. ammonium formate facilitated the recovery of the purified material by allowing the evaporation of the medium in which the sample was eluted.
| 2,911
|
Force development of isoproterenol-damaged frog heart muscle in cyanide anoxia.
|
From recent experiments it is indicated that in frogs living at +25 degrees C the abnormal response to cyanide anoxia appears as soon as 4-5 hr after the first isoproterenol (IPR) injection, but the aneurysm does not appear until a few hours after the second injection of IPR. There is evidently a discrepancy between the biochemical and structural effects of IPR on the heart. The biochemical effects are probably transient as we have observed that a normal response to cyanide reappears a few weeks after the second IPR injection. It might thus be concluded that IPR causes derangement to the cells also in hearts without any visible lesions and demonstrated as a lowered resistance to histotixic anoxia. This effect precedes any structural damage if such should occur and is of a transient nature.
| 2,958
|
[The clinical importance of angiography in the diagnosis of periarteritis nodosa].
|
Report on a 53 years old patient with renal failure. Angiography showed multiple micro-aneurysms in kidneys and liver, in some instances also in the pancreatic, duodenal and mesenterial arteries. Muscle biopsy confirmed the suspicion of arteriitis nodosa. Clinically the diagnosis of necrotizing arteriitis is difficult. Angiography settles the diagnosis, but only positive findings of micro-aneurysms prove it. The differential diagnosis is discussed and illustrated.
| 2,965
|
[Proceedings: Home treatment of chronic respiratory insufficiency: inhalation of beta stimulators].
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In the author's experience, the longterm treatment of chronic obstructive lung disease should be supplemented by continuous selective stimulation of the adrenergic beta-receptors in the smooth bronchial muscles. The following procedure is recommended: inhalation of 15 min 3 times daily using an adequate aerosol with a powered nebulizer (Pari-Privat), with 2-3 ml Tyloxapol carrier solution or saline with 5 drops salbutamol.
| 2,970
|
[Age-related properties of inductive synthesis of glucose-6-phosphatase, fructose-1,6-diphosphatase, tyrosine aminotransferase and tryptophan pyrrolase in hypothalamus stimulation].
|
In aged rats electrostimulation of hypothalamus caused less distinct induction of the enzymes in liver tissue, kidney and spleen as compared with the adult animals. The activation of the total RNA synthesis (actinomycin D and olivomycin) eliminated the alterations in the enzymatic activities, caused by the stimulation of hypothalamus. Effect of adrenalectomy and administration of ACTH suggested that the influence of the hypothalamus stimulation on induction of the enzymes studied was realized through the system hypophysis -- adrenal cortex. In the aged animals activation of adrenal cortex was less distinct when the stimulation of hypothalamus was carried out. The alterations in hypothalamic regulation of the enzyme induction could be an important mechanism in regulation of adaptive reactions in aged organisms.
| 3,019
|
[An improved trihydroxyindole method for the determination of urinary catecholamines].
|
Commercially available columns for ion exchange chromatography were used for the separation of catecholamines in urine. The estimation of catecholamines was performed fluorimetrically by a new trihydroxyindole method. The fluorescence of adrenaline or noradrenaline was enhanced, in comparison with other methods, by the combined application of boric acid, copper-ions, mercaptoethanol and final reacidification. The fluorophores are stable: The loss of fluorescence of adrenolutin amounted to 22% during 180 minutes, and there was no loss of noradrenolutin. For the differentiation of amines, adrenaline was oxidized at pH 2.85 and noradrenaline at pH 7. Precision, accuracy, sensitivity and specifity fulfilled the criteria of analysis. The normal values, determined in a collective of 17 healthy persons, were adrenaline (x +/- s) 44.8 +/- 16.9 nmol/24 h and noradrenaline (x +/- s) 224.0 +/- 68.0 nmol/24h. The simultaneous application of alpha-methyldopa (2 g/day) in 13 patients with primary hypertension did not disturb the fluorimetric estimation of catecholamines.
| 3,040
|
Studies on fragments of rod outer segments from bovine retinas.
|
Monolayers of fragments of our rod segments were formed at an air-water interface. The area of these particles was measured as a function of the pH of the aqueous phase. A maximum area was measured at pH 6.5. The film was characterised by measuring the decrease in surface pressure, after compression, and the half time required to reach constant pressure. At a pH between 6 and 7 the decrease in surface pressure was a minimum. Irradiation of films of fragments resulted in a decrease in surface potential of between 30 and 40 mV. The largest decrease occured at a pH between 6 and 6.5. A small decrease in surface pressure was also observed upon irradiation. Mixed films of fragments and phosphatidyl ethanolamine were examined. Irradiation of the mixed film resulted in a 70 mV decrease in surface potential.
| 3,051
|
Effects of acute metabolic acidosis on parathyroid hormone action and calcium mobilization.
|
Mechanisms through which metabolic acidosis increases calcium mobilization have been investigated in thyroparathyroidectomized rats with induction of acute metabolic acidosis by infusing NH4C1 intravenously. Acute metabolic acidosis directly raised serum calcium concentration and augmented the effect of parathyroid hormone (PTH) to raise serum calcium concentration. The same effects of metabolic acidosis were observed in rats with surgically removed intestines and bilateral nephrectomy, suggesting that acute metabolic acidosis directly increases calcium mobilization from bone and augments the effect of PTH to mobilize calcium from bone. In the kidney, acidosis directly inhibited the tubular reabsorption of calcium, but augmented the effect of PTH to increase tubular reabsorption of calcium. Acidosis had no measurable effect on calcitonin action.
| 3,111
|
Metabolism of histamine in secreting and isolated canine stomach.
|
Total 14C activity in juice secreted by gastric pouches of six dogs and seven isolated canine stomachs was determined in response to intravenous and intra-arterial infusions of histamine and [14C]histamine. The proportions of 14C attributable to histamine, Nalpha-methylhistamine (NalphaMeH), Nalpha,Nalpha-dimethylhistamine (NalphaNalphaMe2H), N-telle-methylhistamine (NtauMeH), imidazole acetic acid (ImAA), N-methylimidazole acetic acid (NtauMeImAA), acetylhistamine (AcH), and histaminol (HOH) were defined using thin-layer chromatography. Similar estimates were made at the end of infusions on blood, gastric mucosa, and gastric muscle. Methylation was the major, or sole, route of metabolism of histamine in the gastric mucosa, and the major product was inactive NtauMeH. Small quantities of the active NalphaMe derivatives, particularly NalphaNalphaMe2H, were identified in both the juice and mucosa. Little or no ImAA, NtauMeImAA, AcH, and HOH were present in juice from isolated stomachs while they did occur in the juice from intact dogs, demonstrating they are extragastric metabolites of histamine. A major mucosal function of methylation of histamine is inactivation, although NalphaMe derivatives formed may play a role in the secretagogue action of histamine.
| 3,112
|
[Comparative study of neuraminidases from "Diplococcus pneumoniae" and "Clostridium perfringens"].
|
Neuraminidases have been purified from the culture medium of two microorganisms, one aerobic, Diplococcus neumoniae, the other anaerobic, Clostridium perfringens. The enzymatic properties of the 2 neuraminidases have been studied (pH optimum; effect of cations; activity toward different substrates: neuraminyllactose, dilactaminyllacto-N-tetraose, gangliosides, alpha1-acid glycoprotein, Collocalia glycoprotein, ovine submaxillary mucin, porcin intestinal and human bronchial mucins).
| 3,129
|
A reporter group delivery system with both absolute and selective specificity for thiol groups and an improved fluorescent probe containing the 7-nitrobenzo-2-oxa-1,3-diazole moiety.
|
1. 4-(N-2-Aminoethyl2'-pyridyl disulphide)-7-nitrobenzo-2-oxa-1,3-diazole (compound I) was synthesized and evaluated as a fluorescent labelling reagent for thiol groups. 2. The design of compound (I) as one example of a general type of reporter group delivery reagent (2-pyridyl-S-S-X, where X contains an environmentally sensitive spectroscopic probe) is discussed. 3. The electronic absorption spectrum of compound (I) was determined over a wide range of pH and the spectral changes that accompany its reaction with low-molecular-weight thiols, e.g. L-cysteine, and with papain (EC 3.4.22.2) and bovine serum albumin are discussed. 4. A new value of epsilon343 for 2-thiopyridone (Py-2-SH) was determined as 8.08 X 10(3) +/- 0.08 X 10(3)M-1-cm-1. 5. Spectral analysis of the reactions of compound (I) with L-cysteine and with papain (in the pH range 3.5-8.0) showed that even under equimolar conditions the reaction (thiol-disulphide interchange to release Py-2-SH) is essentially stoicheimoetric and probably proceeds by specific attack at the sulphur atom distal from the pyridyl ring of compound (I). 6. The fluorescence-emission spectra of compound (I) and of the products of its reaction with papain and with ficin (EC 3.4.22.3) were determined. Compound (I) is highly fluorescent in aqueous solution. Excitation within the intense visible absorption band (lambda max. 481 nm, epsilon max. 2.52 X 10(4)M-1-cm-1) provides green fluorescence with an emission maximum at 540 nm. Both papain and ficin labelled by reaction with compound (I) are characterized by fluorescence-emission maxima (535 nm and 530 nm respectively) of even higher intensity. The fluorescence emission of the product of the reaction of papain with compound (I) was shown to be 25 times more intense than that of the product of the reaction of papain with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (Nbd chloride). 7. The second-order rate constants (k2) for the reactions of compound (I) and of Nbd chloride with GSH, papain, albumin, ficin, 2-benzimidazolylmethanethiol and 2-benzimidazolylethanethiol were determined at 25.0 degrees C and various pH values. At pH4 the values of k2(compound I)/k2(Nbd chloride) are: GSH, 288; albumin, 36; papain 3 X 10(3); ficin, 3 X 10(4). 8. The pH-k2 profiles for the reactions of compound (I) and of Nbd chloride with the two 2-benzimidazolylalkanethiols were determined. Of the four profiles only that for the reaction of compound (I) with 2-benzimidazolylmethanethiol is characterized by a striking rate maximum in acidic media.
| 3,168
|
[Analytical profile of purified hexetidine (author's transl)].
|
Physico-chemical, spectroscopic (UV, IR, NMR, mass), chromatographic (GLC, TLC) properties and synthesis of 1,3-bis(2-ethylhexyl)-5-amino-5-methyl-hexahydropyrimidine (hexetidine) are reported and discussed. Moreover, the difference between commercial and purified hexetidine is demonstrated.
| 3,183
|
[On the influence of a special preparation of oxytetracycline and sodiumbituminosulfonates on amount and composition of skin surface lipids in acne vulgaris (author's transl)].
|
Two groups of 27 and 23 patients with acne vulgaris were first treated for a period of one week with 1 g oxytetracycline a day p.o. In a second treatment period of 6 weeks the first group received 100 mg oxytetracycline a day p.o. and the second group a combination of 100 mg oxytetracycline and 1.2 g sodiumbituminosulfonates a day p.o. In the third treatment period, similarly continued for 6 weeks, the method was reversed. Gastric juice-insoluble preparations were used for the investigation. All criteria for a double-blind study were considered. Amount and composition of the skin surface lipids were analysed before beginning the treatment, at the end of the 2nd and at the end of the 3rd treatment period. The combination of both agents in gastric juice-insoluble preparations suppresses to a great extent the known effects brought about by the substances separately, namely the reduction in free fatty acids and the decrease in the skin surface lipids. The findings also show that the reduction of the free fatty acids was in a limited time observed only in patients treated with 100 mg oxytetracycline a day p.o. if they had been treated in the beginning of this therapy with a higher dosage of tetracycline.
| 3,187
|
[Influence of ethanol on the in vitro and in vivo drug release from some sustained release tablets (author's transl)].
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The in vitro and in vivo liberation of acetylsalicylic acid from sustained release tablets in presence of ethanol is described. Simultaneous uptake of 120 ml commercial brandy resulted in a faster release of the active substance from the tablets prepared with Eudragit ret-l (PM), as has been proved by urinary excretion data. These results were supported by experiments with a pH-endoaradio transmitter and by radiography.
| 3,188
|
Changes in liver function after different types of surgery.
|
Liver function tests carried out after minor surgical procedures, under anaesthesia lasting for 1 hr, showed no abnormalities. Tests after body surface operations under the same anaesthetic techniques showed transient derangements. After intra-abdominal procedures, liver dysfunction was more marked, although no patients with evidence of preoperative liver dysfunction or postoperative surgical complications were studied and none received blood transfusions. Measurements of the serum bilirubin concentration showed the most frequent abnormalities, but the pseudocholinesterase concentration decreased progressively after intra-abdominal surgery and b.s.p. retention increased significantly. Serum concentration of intracellular enzymes (LDH, s.g.o.t. and s.g.p.t.) increased within an hour of starting surgery, changes which were probably not related to liver function.
| 3,192
|
Studies on the energy metabolism in lichen planus.
|
Various epidermal enzymes and cofactors were measured in patients with lichen planus and in healthy controls with the aid of Lowry's microtechniques, including enzymatic cycling. The steady-state levels of the nicotinamide adenine dinucleotides NAD and NADP were decreased and this was evident even in areas still free from lesions. The oxidized and reduced portions of NAD were altered indicating changed equilibria of NAD dependent dehydrogenases. Reduced NADP was more tightly controlled at the normal level which is regarded as evidence of an unaltered biosynthetic potential in this disease. In conjunction with earlier data the results indicate a preserved glycolytic and pentose shunt activity while the mitochondria display signs of dysfunction.
| 3,193
|
A kinetic study of protein-protein interactions.
|
Kinetic studies have been carried out of the monomer-dimer interaction of insulin, beta-lactoglobulin, and alpha-chymotrypsin using stopped-flow and temperature-jump techniques. The pH indicators bromothymol blue, bromophenol blue, and phenol red were used to monitor pH changes associated with the monomer-dimer interaction. In all three cases a kinetic process was observed which could be attributed to a simple monomer-dimer equilibrium, and association (k1) and dissociation (k-1) rate constants were determined. The results obtained are as follows: for insulin at 23 degrees C, pH 6.8, 0.125 M KNO3, k1 = 1.14 X 10(8) M-1 s-1, k-1 - 1.48 X 10(4)s(-1); for beta-lactoglobulin AB at 35 degrees C, pH 3.7, 0.025 M KNO3, d1 = 4.7 X 10(4) M-1 s-1, k-1 = 2.1 s-1; for alpha-chymotrypsin at 25 degreesC, pH 4.3, 0.05 M KNO3 k1 - 3.7 X 10(3) M-1 s-1, k-1 - 0.68 s-1. The kinetic behavior of the separated beta-lactoglobulin A and B was similar to that of the mixture. In the case of chymotrypsin, bromophenol blue was found to activate the enzyme catalyzed hydrolysis of p-nitrophenyl acetate, and a rate process was observed with the temperature jump which could be attributed to a conformational change of the indicator-protein complex. The association rate constant for dimer formation of insulin approaches the value expected for a diffusion-controlled process, while the values obtained for the other two proteins are below those expected for a diffusion-controlled reaction unless unusally large steric and electrostatic effects are present.
| 3,211
|
Studies on some lipogenic enzymes of cultured myeloid leukemic cells.
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The microsomal fraction of M1 cells (an established cell line of myeloid leukemia) was capable of catalyzing acylation of sn-glycerol 3-phosphate by long-chain fatty acyl-CoA thioesters. The principal lipid product formed was identified as phosphatidic acid. Palmityl-CoA, stearyl-CoA, and oleyl-CoA were more effective acyl donors than linoleyl-CoA and arachidonyl-CoA. M1 cells and macrophages differentiated from them exhibited similar levels of sn-glycerol 3-phosphate-acylating activity, which were approximately one-half that in mouse liver and approximately four times that in peritoneal macrophages. The levels of acetyl-CoA carboxylase activity in M1 cells and macrophages differentiated from them were not significantly different from each other and were comparable to those in mouse liver, whereas no activity was detected in peritoneal macrophages. These results indicated that differentiation of the myeloid leukemic cells, which results in loss of leukemogenicity and mitotic activity, is not associated with changes in the activities of these lipogenic enzymes, although the cultured cells exhibited remarkably higher activities than freshly harvested peritoneal macrophages. Furthermore, the present study supports the view that the glycerophosphate pathway makes an essential contribution to the de novo synthesis of phospholipids in M1 cells, as well as in both types of macrophages.
| 3,240
|
The expectation of outcome from maintenance therapy in chronic schizophrenic patients.
|
The results from a prospective follow-up study of a group of schizophrenic patients suggest that a significant proportion (41 per cent) are likely to relapse during a two-year period despite the prescription of long-acting injectable neuroleptic drugs. Some will relapse because of a failure of the regime, but others (32-37 per cent) because the pharmacological protection of these drugs would appear to be less effective in certain patients. Even with the major advantages of the long-acting injectable neuroleptics over oral medication, the schizophrenic patient population remains a group with a high incidence of psychiatric and social morbidity which continues to require the full resources of both the hospital and community services.
| 3,251
|
New techniques for ion-selective measurements of ionized calcium in serum after pH adjustment of aerobically handled sera.
|
I report further experience in measuring ionized calcium (Ca2+) with the AMT Electron System and its serum standards and solid-state, dip, calcium-selective electrodes. With this system, serum pH can be adjusted with CO2 gas and Ca2+ and pH simultaneously measured; when 5.2% CO2 (40 mm pco2) is used for sample equilibration, the standard bicarbonate concentration is also provided. I measured serum Ca2+ as a function of pH between pH 7.0 and 9.0 and found the relationship to be reproducible, with no evidence of irreversible complexing of Ca2+. When the pH of aerobically exposed, mailed sera was restored to the original values, their values for Ca2+ were the same as for the fresh sera. Measurement of Ca2+ in routinely (aerobically) handled sera after pH restoration with CO2 gas was therefore validated, both samples from within an institution and mailed specimens. Standardization to pH 7.40 is recommended for routine measurements, is generally more accurate than use of heparin or quasianaerobic techniques, and is a practical approach. In patients with possible uncompensated acid-base disturbance (which may be indicated by an abnormal standard bicarbonate concentration if not suspected clinically), patient pH should be measured independently as part of the usual strict, anaerobic blood-gas-analysis procedures. Abnormal patient pH must be considered in the interpretation of Ca2+ results determined at pH 7.40 which are borderline or slightly abnormal; most accurately, Ca2+ may be measured in the separated sera at the previously determined patient pH value. Studies of aqueous solutions with the currently used Ca2+ electrodes showed a selectivity coefficient (the constant which relates the activity of an interfering ion to the activity of calcium that would contribute the same emf) KNa=0.0031 +/- 0.0003 (SE) and KMg=0.046 +/- 0.004 (SE). At physiological concentrations of Ca2+, physiologically encountered variation in Na+ is of no significance in resulting Ca2+, but extreme variation in Mg2+ may cause an error of approximately 1%.
| 3,297
|
Elastin--proteoglycan interaction. Conformational changes of alpha-elastin induced by the interaction.
|
The interaction between alpha-elastin and a connective tissue proteoglycan was followed by optical density measurements and circular dichroism spectroscopy. It was found that interaction takes place at pH values below the isoelectric point of elastin with the formation of a complex coacervate. CD spectra demonstrated conformational changes of alpha-elastin caused by the interaction and resulting in an increase in the content of helical structure. This finding suggests the possibility of the involvement of proteoglycans in the molecular organization of elastin.
| 3,386
|
The influence of dehydrocholate on hepatic uptake and biliary excretion of 3H-taurocholate and 3H-ouabain.
|
The hepatic uptake and biliary excretion of 3H-taurocholate and 3H-ouabain was studied in the rat during saline (control) and dehydrocholate infusions. Dehydrocholate (140 mumol/hr) did not influence the plasma disappearance nor the biliary excretion of taurocholate after a single iv injection (37 mumol/kg). Bile production in the dehydrocholate experiment was increased 2- to 3-fold compared with controls. The biliary transport maximum for exogenously administered taurocholate was determined by constant infusion to be 135.0 +/- 3.0 mumol/hr (22 mumol/min/g of liver). Concomitant infusions of 140 mumol of dehydrocholate per hr did not alter the maximal taurocholate output. The effects of the two bile salts on bile flow were additive. Dehydrocholate (140 mumol/hr) reduced the biliary excretion of 3H-ouabain (0.8 mumol/kg) and elevated the secondary slow component of the plasma disappearance of the cardiac glycoside. The hepatic levels of ouabain were increased compared with controls. It is concluded that dehydrocholate interferes with ouabain transport at the canalicular level but not with primary hepatic uptake. Taurocholate (140 mumol/hr) failed to influence the total biliary output of ouabain. These differences and the lack of interaction between dehydrocholate and taurocholate suggest a hepatic transporting pathway for taurocholate which differs from that for taurocholate which differs from that for dehydrocholate and/or its metabolites.
| 3,395
|
Physiological disposition and metabolism of N-t-butylarterenol and its di-p-toluate ester (bitolterol) in the rat.
|
The metabolism and disposition of the bronchodilator, N-t-butylarterenol (tBA) and its di-p-toluate ester (bitolterol) were compared in the rat. Radioactivity was preferentially retained in lungs of rats compared with heart and blood after iv medication with tritium-labeled bitolterol, but was not retained in tissues after iv medication with [3H]tBA. After oral and iv medication with [3H]bitolterol, fecal radioactivity accounted for 24% of the dose and 65 and 79% of the radioactivity, respectively, was excreted in urine (0-72 hr). In comparison, urine radioactivity after oral and iv medication with [3H]tBA was 43 and 83% of the dose, respectively, and fecal radioactivity accounted for 43 or 23% of the dose, respectively (0-72 hr). Bitolterol was hydrolyzed in vitro to tBA by esterases found in various tissues including small intestine, liver, and plasma. Moreover, tBA was a substrate for catecholamine O-methyltransferase but not for monoamine oxidase. Similar metabolites were observed in urine samples of rats given either [3H]tBA or [3H]bitolterol. Urine metabolites were identified as free and conjugated forms of both tBA and 3-O-methyl-tBA.
| 3,403
|
[Responses of small intestine tissue chemoreceptors to change in the pCO2, pH and (HCO3-) in perfusion solutions].
|
Perfusion of the small intestine of anesthetized cats with a solution having excessive CO2 and H+ concentration (pCO2 60 mm Hg; pH; 7.2; [HCO3-] 25 MM) produced a threshold reflex increase in the blood pressure. The subsequent increase of pCO2 to 380 mm Hg and decrease of pH to 6.4 evoked a gradual raise of the blood pressure (8.0+/-0.6 mm Hg) followed by the sharp increase of pressor reflexes amplitude within the range of pH 6.4--6.1. Tissue receptors were found to be essentially sensitive to solutions imitating metabolic acidosis (decrease of [HCO3-] within the physiological range of pH changes (pH 7.1--6.8). Solutions with pH 6.4--6.1 imitating respiratory acidosis (increase of pCO2) were more effective than those imitating metabolic acidosis. The possible role of interstitial pH changes in responses of the tissue chemoreceptors to CO2, is discussed.
| 3,446
|
Post-prandial changes in PH and electrolyte concentration, in the upper jejunum after truncal vagotomy and drainage in man.
|
The changes in pH and concentration of electrolytes in the jejunal lumen after a hypertonic fluid meal have been studied after truncal vagotomy and drainage, with and without diarrhoea. The results show that, in these respects, there are no specific changes in the jejunal content associated with post-vagotomy diarrhoea, but that these measurements are markedly affected by the completeness of vagotomy, as judged by the insulin test.
| 3,456
|
[Conditions for the efficacy of nutritional therapy].
|
This is to discuss regulatory mechanisms which enable the organism to respond optimally to special nutritive conditions. Those regulatory mechanisms are often in disorder with patients who need nutritive therapy. However, normal functions of the body are required for nutrition. Disarrangements in microcirculation, oxygen supply, water and electrolyte metabolism and acid-base metabolism are described and the way they will influence nutrition therapy. Furthermore, we try to describe special conditions of metabolism in stress and its influence to efficiency of nutritive therapy.
| 3,471
|
Increased fibrinolytic activity in the endometrium of patients using copper-iud (gravigard).
|
The use of an IUD often causes an increase in the menstrual blood loss, and this is the most common reason for removing the device. The fibrinolytic activity of the endometrium was studied histochemically in 15 women before and after the use of copper-IUD for 2-5 as well as for 8-12 months. The fibrinolytic activity in the endometrium was found to be increased at both examinations. This increase is probably a contributory cause of the menorrhagia in patients with IUD. No significant difference in fibrinolytic activity was found between the two examinations after insertion of the IUD, which thus suggests that the increase in endometrial fibrinolytic activity was steady.
| 3,481
|
Urea transport-defective strains of Saccharomyces cerevisiae.
|
Experiments characterizing the urea active transport system in Saccharomyces cerevisiae indicate that (i) formamide and acetamide are strong competitive inhibitors of urea accumulation, (ii) uptake is maximal at pH 3.3 and is 80% inhibited at pH 6.0, and (iii) adenosine 5'-triphosphate generated by glycolysis in conjunction with formation of an ion gradient is likely the driving force behind urea transport. Mutant strains were isolated that are unable to accumulate urea at external concentrations of 0.25 mM. These strains also exhibit a depressed growth rate on 10 mM urea, indicating existence of a relationship between the active transport and facilitated diffusion modes of urea uptake.
| 3,491
|
The determination of phanquone in biological material by gas-liquid chromatography.
|
A gas-liquid chromatographic method for the quantitative determination of phanquone is described, based on the formation of a dimethoxine prior to its extraction from biological material. The sensitivity of the procedure is about 15 ng/ml in biological fluid.
| 3,515
|
[Has the pH meter replaced the Apgar score?].
|
The introduction of measuring the pH appears to place it in competition with Apgar scoring because of its precision. A study of this which has been carried out has illustrated that there are two different criteria for assessing the state of the infant at birth. The usual agreement between pH values and Apgar scoring can be broken when clinical fetal distress has become established before metabolic equilibrium of the infant has become modified. In these circumstances the Apgar score will be bad while the pH will be good.
| 3,546
|
Immunology of DNA. I. The influence of reaction conditions on the Farr assay as used for the detection of anti-ds DNA.
|
The sensitivity and the specificity of the Farr assay for the detection of antibodies to double stranded (ds) DNA depends very much on the reaction conditions. The interaction between ds DNA and anti-ds DNA is inhibited when ionic strength and pH are increased. ds DNA is bound by normal sera at ionic strength lower than 0.11 M NaCl and at physiological ionic strength when the pH is lower than 7.2. Substantial binding of DNA by normal serum takes place in barbitone, borate or Tris-HCl buffers at concentrations of 30 mM or higher, even at a pH higher than 7.2. Such binding is due to Clq and is only partially prevented by heating the serum for 30 min at 56 degrees C, but 10 mM phosphate in the incubation mixture completely prevents it. Standardization of ionic strength, pH, phosphate concentration, incubation volume and DNA-serum ratio enhances the diagnostic usefulness of the Farr assay.
| 3,611
|
Further evidence for histamine facilitating oestrogen action in the uterus.
|
The effect of doses of estradiol ranging from 0-0125 to 1-6 mug on the uterine weight of the spayed rat was studied 24 h after a single s.c. injection of the hormone. The lowest dose inducing a significant increase in uterine weight was 0-32 mug. When histamine dihydrochloride (50 mg) was simultaneously injected with the hormone, the effect of small doses of oestradiol (0-0125--0-2 mug) was significantly increased. When oestradiol and histamine were administered for 3 successive days, the uterine weight of animals receiving 0-0125 mug oestradiol, if compared with untreated controls, was increased only in the histamine-treated group. When 0-05 mug oestradiol was administered histamine did not modify the increase already produced by the hormone. Spermidine and burimamide, two substances structurally related to histamine, increased [3H]oestradiol uptake by the spayed rat uterus. The latter (an antihistamine drug acting on H2-receptors) as well as pyrathiazine (a histamine releaser having antihistamine properties) decreased the effect of histamine on oestradiol uptake whereas diphenhydramine (an antihistamine drug blocking H1-receptors) did not modify it. Pyrathiazine was itself able to diminish oestradiol uptake.
| 3,616
|
Concentrations of bacteria in cerebrospinal fluid of patients with bacterial meningitis.
|
Concentrations of bacteria in cerebrospinal fluid ranged from 4.5 X 10(3) to 3 X 10(8) colony-forming units/ml in 27 patients with bacterial meningitis before antibiotic therapy and from 4 X 10(1) to 1.4 X 10(6) CFU/ml in four patients after one to two days of antibiotic therapy. All patients with persistent positive cultures had pretreatment concentrations of 10(7) CFU/ml or greater. A significant association was observed between cerebrospinal fluid lactic acid dehydrogenase activity and concentrations of bacteria (p less than 0.01). Large inocula of Hemophilus influenzae type b (10(7)) increased the minimal inhibitory concentration for penicillin and ampicillin but not for chloramphenicol. The minimal inhibitory concentration of each of the three antibiotics increased when group B streptococci were assayed. These data indicate that persistence of a positive culture may be related to large initial concentrations of bacteria. The relative "resistance" in vitro of large inocula possibly contributes to this persistence. These observations are also consistent with the hypothesis that lactic acid dehydrogenase activity in cerebrospinal fluid is derived from bacteria.
| 3,635
|
Neurogenic influences of bilateral adrenalectomy on monoamine oxidase.
|
Bilateral adrenalectomy (10 days) increased the monoamine oxidase activity of the rat heart, vas deferens, spleen, superior cervical ganglion, and hypothalamus but not that of the rest of the brain, kidney, and liver. Experiments were made to determine whether the increased activity was due to neurogenic influences and whether the enhanced activity of monoamine oxidase was intra- or extraneuronally located. Ganglionic blockade with chlorisondamine failed to alter the rise in cardiac monoamine oxidase. Likewise, superior cervical ganglion monoamine oxidase was unaffected by surgical denervation. 6-Hydroxydopamine abolished the increase in monoamine oxidase activity of the vas deferens, spleen, and superior cervical ganglion but failed to alter that of the kidney, hypothalamus, and the rest of the brain. Cardiac monoamine oxidase was reduced markedly by 6-hydroxydopamine, but the remaining activity was still significantly elevated over the respective control values. The data suggest that the increase in organ monoamine oxidase is predominantly of neuronal origin and that this increase is not due to transsynaptic induction.
| 3,640
|
Intraspecific variations in the hemolymph of Biomphalaria glabrata, a snail host of Schistosoma mansoni.
|
An attempt was made to characterize the hemolymph of Biomphalaria glabrata with reference to "normal" intra-specific variation, i.e., both inter- and intra-strain differences. Total protein concentration, per cent hemoglobin, pH, and osmolarity were studied. Seven geographic strains of B, glabrata were examined. In addition, observations were made on the hemolymph of Biomphalaria straminea, several strains of Helisoma caribaeum, and on B. glabrata subjected to infection with Schistosoma mansoni or to periods of starvation. Intra-strain differences in total protein concentration and total hemoglobin concentration in B. glabrata appeared to be more closely related with snail size than with absolute age. Inter-strain variation in B. glabrata was also noted, but the differences were of the same magnitude as those from intra-strain samples. Significant differences in total protein concentration were observed, however, between the means of similar size B. glabrata, B. straminea and H. caribaeum. The osmolatity of the hemolymph from different size B. glabrata was similar as were the osmolalities of the hemolymph from similar size snails of different strains. However, all B. glabrata strains exhibited hemolymph osmolalities lower than observed in strains of H. caribaeum. Infection with S. mansoni reduced the protein concentration of B. glabrata hemolymph. Differences were noted as early as 1.5-24 hr post-infection, with significant alterations occurring at about 11 days post-infection. To a lesser extent, starvation also depleted the protein content of the hemolymph.
| 3,698
|
[Relevance of biochemistry in diagnosis and development of alcoholic liver disease (author's transl)].
|
In a group of 205 patients with alcoholic diseases of liver the diagnostic relevance of biochemical tests (GOT, GPT, AP, GGTP, BSP) was reconsidered with discriminatory process (separation of diagnosis). The group contained 16 patients with nutritional-caused and 41 cases with alcoholic-caused fatty-infiltration of liver. 148 patients showed a toxic chronic liver disease; 52 a chronic hepatitis and 96 cirrhosis of liver. Laparoscopy and morphology guaranteed the clinical diagnosis and therefore the accuracy of biochemistry in separation of diagnosis was given. The biochemical tests were not able to offer a separation of fatty-infiltration with reference to cause, changes of the process in toxic hepatitis and cirrhosis were announced. Intersection in several cases was noticed and biochemical tests were not able to substitute endoscopy and morphology for clinical and diagnostic use in all cases. In every regard the enzyme-tests,--above mentioned--, and determination of sulfobromthalein are aptly to development of diseases and deficiency of alcohol.
| 3,720
|
[A compact form of DNA in solution. 2. Peculiarities of acidic titration of double-stranded DNA in PEG-containing water-salt solutions].
|
The formation of compact double-stranded DNA molecules in PEG-containing watersalt solutions (0.3 M NaCl) may be observed within the pH-range 3-10; i.e. under conditions at which parameters of double-stranded DNA helices are not strongly different from those of B-form. At pH less than 3, when regularity of double helices is significantly changed, the formation of the specific compact particles of DNA in PEG-containing solutions does not take place. Denaturation of the compact form of DNA in PEG-containing solution is accompanied by disappearance of the negative band in CD spectrum. Hyperchromic effect of denaturation of DNA compact form is uninformative because of the influence of the light-scattering by compact DNA molecules.
| 3,728
|
Cyclic AMP and neuroendocrine influence upon forelimb regeneration in the adult newt, Notophthalmus viridescens.
|
The influence of the nervous and endocrine systems upon successive stages of limb regeneration suggest possible neuroendocrine interaction(s). Intraperitoneal injections of various agents had no effects upon blastema formation. Chlorpromazine, administered alone or with hormones, retarded morphogenesis. Prolactin, dibutyryl cAMP (db-cAMP), theophylline, and acetylcholine accelerated morphogenesis. 5'-AMP had no effect. Only db-cAMP countered the chlorpromazine-induced retardation of morphogenesis. These results suggest that neuroendocrine influences, possibly cAMP-mediated, direct, in part, the morphogenesis of the regeneration blastema.
| 3,753
|
On the influence of prostaglandin F2alpha-induced labor at term on the metabolism and coagulation of mother and fetus.
|
11 pregnancies at term were terminated by dilatation of the uterine cervix, low amniotomy, and by intravenous administration of PGF2alpha. The average infusion time was 3 hours 55 minutes, and the average total dose of PGF2alpha amounted to 2.0 mg. Parameters of acid-base changes, carbohydrate and energic state changes, gas metabolism, and changes in coagulation and fibrinolysis in mother and in fetus were analyzed during labor and after birth. Labor activity and fetal cardiac action were monitored cardiotocographically. Checked against 50 uncomplicated spontaneous deliveries, we found no disadvantageous changes in the parameters investigated.
| 3,823
|
Dopamine receptor binding predicts clinical and pharmacological potencies of antischizophrenic drugs.
|
Tritiated haloperidol and tritiated dopamine label postsynaptic dopamine receptors in mammalian brain. Clinical potencies of butyrophenones, phenothiazines, and related drugs correlate closely with their ability to inhibit tritiated haloperidol binding. These binding methods provide a simple in vitro means for evaluating new drugs as potential antischizophrenic agents.
| 3,854
|
Metomidate as sole anaesthetic agent in tawny owls.
|
Metomidate 1 per cent was administered intramuscularly as the sole anaesthetic agent on 22 occasions to seven tawny owls (Strix aluco). Four deaths occurred, none on the first administration. ECG findings and details of dosage are provided. The possible causes of death are discussed.
| 3,876
|
[Dynamics of production and various properties of interferon-like inhibitors formed under the influence of AET and cystaphos in vivo and in cell cultures].
|
Interferon-like virus inhibitors appeared in the blood serum of animals and in the culture fluid 15 min.--1 hour and 4-6 hours after administration of AET (S, beta-amino-ethylisotiuronium) and cystaphos (monosodium salt of beta-aminoethylthiophosphorus acid). These inhibitors showed species-specificity, were inactivated by trypsin and by heating at 37 degrees C for 2 hours and at 56 degrees C for 1 hour, did not sediment at 100,000 g. It is assumed that these are two different inhibitors of which the one forming the early peak pre-exists in the cell. It is probably associated with cell membranes and is released as a result of chemical effect of aminothyols. The late peak of inhibitor is synthesized de novo as inducated by its sensitivity to the effect of puromycin and cycloheximide.
| 3,884
|
[Lipolysis in human adipose tissue (author's transl)].
|
Lipolytic activity was measured under different conditions in isolated fat cells and homogenates of human adipose tissue of the greater omentum. It was demonstrated that lipolysis took place in isolated fat cells at an optimum pH of 7.4 and was markedly stimulated by noradrenaline, but not by blood serum. By contrast lipolysis was significantly stimulated by blood serum, but not by noradrenaline, in homogenates of adipose tissue. Serum-stimulated lipolysis exhibited optimum activity at pH 8 and was inhibited by 1M sodium chloride. It is concluded that lipolytic activity in isolated fat cells can mainly be ascribed to the action of hormone-sensitive lipase, whereas lipolysis in homogenates of adipose tissue in the presence of serum is mostly regulated by lipoprotein lipase.
| 3,890
|
[Possibilities and limits of the intrauterine reanimation (author's transl)].
|
Intrauterine reanimation means the removal of acute maternal or fetal distress. Beside of maternal shock (traumatic, hoaemorrhagic, supine hypotension syndrome) all acute distress situation are seen during labour. The therapeutical possibilities and premises on the one side, the limits and dangers on the other are discussed. There are the change of position in bed, infusion of low molecular dextrane, O2- breathing, buffering of the mother, infusion of vasodilatators and beta-stimulators to the mother. The main therapeutical principle for intrauterine reanimation are change of side position and beta-stimulator therapy in case of disturbances in feto-maternal respiration because of an acute utero-placental insufficiency or a cord complication. As to an own patient group with intrauterine reanimation with the beta-stimulator "Partusisten" in 174 deliveries with cardiotocographic signs of fetal distress in the first stage of labour there is shown that threatened fetal distress because of uterine hyperactivity and cord complication is successfully treated by tocolysis. In case of chronic placental insufficiency there is no therapeutical success by intra partum tocolysis in 30%.
| 3,899
|
Graft-versus-host reaction: a pathogenetic principle for the development of drug allergy, autoimmunity, and malignant lymphoma in non-chimeric individuals. Hypothesis.
|
It is proposed that the same diseases as those induced by the graft-versus-host reaction (GVHR) will arise in nonchimeric individuals, if structures of the major histocompatibility complex (MHC) on lymphocytes are altered, either by viral infection or by chemicals, in such a way that autologous T lymphocytes react against them as the react in the GVHR to semiallogeneic (F1) lymphocytes differing at the MHC. Diseases in which a GVHR-like pathogenesis is suspected will be discussed.
| 3,900
|
[Preparation of the lectin B component from the hemagglutinin of Lens culinaris].
|
Out of a mixture of both lectins of the lentil (Lens culinaris) the component B may be separated rapidly and easily because of the different temperature sensitivity of haptene protected isolectins A and B.
| 3,927
|
Bactericidal activity and pharmacology of flucloxacillin.
|
Flucloxacillin, a recent addition to the group of isoxazolyl penicillins, was studied in vitro and in normal volunteers. The bactericidal activity of the drug against most strains of gram-positive bacteria including penicillin-resistant Staphylococcus aureus was similar to that of oxacillin and approximately fourfold greater than that of cloxacillin. Each of the three penicillins was administered orally to a group of ten volunteers for eight days in a dose of 500 mg four times a day. The mean concentrations of flucloxacillin in the serum were two- to sixfold higher than those of the other two agents on the first, fourth and eighth days of therapy. The percentage of flucloxacillin bound by serum protein was 94.6 per cent; for cloxacillin and oxacillin the values were 93.5 and 91.5 per cent, respectively. Using these data, the concentrations of free flucloxacillin in serum were found to be twice as high as those of cloxacillin and oxacillin. These findings suggest that, when administered orally, this new agent may offer some therapeutic advantage over oxacillin and cloxacillin.
| 3,969
|
[Endocrine cells of the gastric mucous membrane].
|
In order to obtain an additional information concerning a possible functional role of the main types of the endocrine cells (EC and ECL) on investigation of aspiration biopsy specimens taken from the middle third of the stomach in patients with ulcerative disease of the duodenum and chronic gastritis was carried out. Changes in morphology, distribution and number of the endocrine cells in pathology of the mucosa and in various acidity of the gastric juice were followed up. On the basis of the data obtained the conclusion is made that serotonin-producing (EC) cells seem to have nothing to do with the regulation of the activity of the fundal glands, whereas the enterochromaffin-like cells (ECL) influence the production of hydrochloric acid by pavement cells.
| 4,052
|
Anomalous fluorescence of yeast 3-phosphoglucerate kinase.
|
The 3-phosphoglycerate kinase (EC 2.7.2.3) of yeast which contains two tryptophyl and eight tyrosyl residues per molecule, displayed an unusualy fluorescence emission spectrum with a maximum at 308 nm when excited at 280 nm. The emission peak shifted to 329 nm when excited at 295 nm. We could confirm that it was due to the efficient quenching of tryptophyl fluorescence as well as to the incomplete energy transfer from tyrosyl to tryptophyl residues. The average fluorescence quantum yield of this protein was 0.076 (excitation at 280 nm) and that of tryptophyl residues was 0.046 (excitation at 295 nm). As the pH of the solution was lowered, the fluorescence intensity of phosphoglycerate kinase at 329 nm dramatically increased between pH 5 and 4, while the position of the peak remained unchanged. When denatured in 4 M guanidine hydrochloride, the protein showed two emission peaks, one at 343 nm and the other at 303 nm.
| 4,108
|
A study of the single polypeptide nature of rhodanese. A comparison of different preparations.
|
The enzyme rhodanese (EC 2.8.1.1) appears as a single polypeptide chain protein on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The molecular weight of this species is approx. 33 000. This contrasts with previous reports that rhodanese behaves on gel filtration chromatography as a rapidly equilibrating monomer-dimer system composed of identical subunits with a molecular weight of 18 500. We have investigated this apparent discrepancy by isolating the enzyme by the two different preparative procedures used in the above investigations. The two crystalline samples were subjected to gel filtration chromatography under a wide variety of conditions and to sodium dodecyl sulfate disc gel electrophoresis. The two preparations yielded rhodanese which behaved identically and no evidence for the monomeric species was obtained under any experimental condition tested. Thin-layer gel chromatography of clarified liver homogenates gave no evidence of rhodanese species other than that present in the purified samples. The variation in molecular weights observed in gel filtration chromatography may be a reflection of the conformational mobility of the enzyme leading to solvent-dependent changes in Stokes radius. If rhodanese is dimeric, special interactions must stabilize it under the conditions tested here.
| 4,117
|
Purification and properties of NADP-dependent glutamate dehydrogenase from yeast nuclear fractions.
|
1. NADP-dependent glutamate dehydrogenase (EC 1.4.1.4) extracted from nuclear fractions of Saccharomyces cerevisiae was partially purified. The final purification achieved was over 100-fold over the initial extract. 2. Cellulose acetate electrophoresis shows that the preparation is close to homogeneity and that the enzyme is slightly more anionic than cytoplasmic glutamate dehydrogenase. 3. The response of the nuclear activity to variation of pH, of inorganic phosphate and other electrolyte concentration and of the concentration of the reaction substrates has been investigated. Several differences were detected in comparison with cytoplasmic glutamate dehydrogenase.
| 4,126
|
Ascorbic acid-2-sulfate sulfhohydrolase activity of human arylsulfatase A.
|
Pure human arylsulfatase A (EC 3.1.6.1) was found to hydrolyze ascorbic acid 2-sulfate to ascorbic acid and inorganic sulfate at rates from 200 to 2000 mumol/mg per h depending on the method of assay. This rate was lower than that observed with the synthetic substrate 4-nitrocatechol sulfate, but higher than that seen with the physiological substrate cerebroside sulfate. Extracts of cultured fibroblasts from normal subjects were also shown to hydrolyze ascorbic acid 2-sulfate; extracts of fibroblasts from patients with metachromatic leukodystrophy, known to be deficient in arylsulfatase A, did not. Similarly, hydrolysis of ascorbic acid 2-sulfate was not observed when a partially purified preparation of human arylsulfatase B was tested under a variety of conditions. Thus, in the human, arylsulfatase A appears to be the major, if not the only, ascorbic acid-2-sulfate sulfohydrolase.
| 4,134
|
Evidence against proton gradient formation being the cause of chlorophyll fluorescence quenching by N-methylphenazonium methosulfate.
|
In strong illumination, 3-(3, 4-dichlorophenyl)-1,1-dimethylurea (DCMU)-poisoned chloroplasts exhibit a high yield of chlorophyll fluorescence while P-700 turnover, proton uptake, and phosphorylation are inhibited and a pH gradient is undectectable. When 10muM N-methylphenazonium methosulfate (PMS) is included, the fluorescence yield in light is substantially reduced, and when 100 muM ascorbate is also included, the yield is diminished approximately to the level in darkness. Only very slight increases in P-700 turnover and proton uptake (but no detectable pH gradient) accompany the fluorescence yield decline. When 10muM PMS and 15 mM ascorbate are added to poisoned chloroplasts (the oxygen concentration being greatly reduced), P-700 turnover, proton uptake, the pH gradient and phosphorylation all reach high levels. In this case, the yield of chlorophyll fluorescence is low and is the same in both light and dark. Further addition of an uncoupler eliminates proton uptake, the pH gradient and phosphorylation but does not significantly elevate the fluorescence yield. From these observations we suggest that, in DCMU-poisoned chloroplasts, the fluorescence quenching with PMS occurrs by a mechanism unrelated to the generation of a phosphyorylation potential. With chloroplasts unpoisoned by DCMU, PMS quenches fluorescence and considerably stimulates proton uptake, the pH gradient and phosphorylation. However, in this case, PMS serves to restore net electron transport.
| 4,143
|
The accumulation of superoxide radical during the aerobic action of xanthine oxidase. A requiem for H2O4.
|
The action of xanthine oxidase upon acetaldehyde or xanthine at pH 10.2 has been shown to be accompanied by substantial accumulation of O2- during the first few minutes of the reaction. H2O2 decreases this accumulation of O2- presumably because of the Haber-Weiss reaction (H2O2+O2- leads to OH- +OH+O2) and very small amounts of superoxide dismutase eliminate it. This accumulation of O2- was demonstrated in terms of a burst of reduction of cytochrome c, seen when the latter compound was added after aerobic preincubation of xanthine oxidase with its substrate. The kinetic peculiarities of the luminescence seen in the presence of luminol, which previously led to the proposal of H2O4-, can now be satisfactorily explained entirely on the basis of known radical intermediates.
| 4,144
|
Purification and properties of cyclic AMP dependent and independent protein kinases from rat pancreas.
|
Three protein kinases Ko, K1, and KII have been extracted from rat pancreas homogenate, Ko is not stimulated by cyclic AMP. K1 is poorly stimulated by cyclic AMP (1.3 times), Ku is highly stimulated (6 times). The specificity of KII with respect to various nucleotides and cyclic nucleotides has been determined. K1 and KII account for the total cyclic AMP dependent protein kinase activity in the homogenate.
| 4,157
|
[Interactions of phosphorylethanolamine analogs with phosphorylethanolamine-citidylyltransferase].
|
Kinetic studies of ethanolaminephosphate-cytidylyltransferase (E.C. 2.7.7.14) from rat liver have been carried out in presence of structural analogues of ethanolaminephosphate : these compounds acted as inhibitors of the enzyme: - 2-aminoethylphosphonate behaved as a substrate and a competitive inhibitor to phosphorylethanolamine: the Km value of 2-aminoethylphosphonate was nearly the same as its Ki value, at pH = 5,5 (30 X 10(-3) M and 24 x 10(-3) M, respectively). - 3-aminopropylphosphonate was also a competitive inhibitor. It appeared to be the best inhibitor at pH optimum (pH = 7,7). - 1-aminoethylphosphonate behaved as a noncompetitive inhibitor. However, cytidylyltransferase was relatively specific, inhibitions being always weak. Inhibitory power of phosphonates was stimulated by Mg++.
| 4,159
|
Superficial cell-wall layers on Spirillum "Ordal" and their in vitro reassembly.
|
The cell envelope of Sporillum sp. strain "Ordal" (possibly a variety of S. anulus) demonstrated multiple superficial wall layers which were diverse in their macromolecular arrays. Negative staining and freeze-etching techniques revealed an outer hexagonally packed layer and an inner tetragonally packed layer. However, both thin sections and freeze-etched cleavages of the wall showed that each of these regular structures rested upon a backing layer, and that there was a delicate amorphous layer overlying the outer hexagonal array. Rotary integration, optical deffraction, and reconstruction of image were used to clarify measurements of each array and to verify the validity of a diagrammatic model of the outer hexagonal system. The integrity of these layers required suitable cations (Ca2+ appeared essential) and pH (pH less than or equal to 4.6 dissociated most superficial layers). These observations aided in the development of a low-pH cationic-substitution technique, in which Na+ replaced essential Ca2+, for extraction of the layers from the cell surface. Dialysis to remove Na+ and restoration of Ca2+ initiated in vitro reassembly of the superficial layer components until regularly structured assembly products were formed.
| 4,216
|
Premature labour.
|
Prematurity is by far the commonest cause of neonatal morbidity and mortality. The management of premature labour is empirical because little is understood about the mechanism of labour. Effective uterine relaxant drugs have an important, albeit minor role. Phototherapy has reduced the complications of neonatal hyperbilirubinemia, and the beneficial effect of antepartum corticosteroid therapy in minimizing the risk of respiratory distress syndrome is now convincing. Prophylactic antibiotic therapy in premature rupture of the membranes does not alter perinatal mortality, although postpartum maternal morbidity is reduced. The introduction of neonatal intensive care units has improved the survival rate of premature infants. Sound clinical judgement remains the mainstay in the management of premature labour.
| 4,217
|
31P nuclear magnetic resonance-pH titrations of myo-inositol hexaphosphate.
|
With the use of 31P n.m.r. spectroscopy, the separate pKa values of each of the six phosphoric monoester groups of myo-inositol hexaphosphate were determined. The range of hydrogen-ion concentrations covered extended from that required for the phosphonium salts to that for the full dodecyl anion, and the determinations were carried out in the presence of sodium and tetrabutylammonium cations. The pKa for each phosphate grouping in the transition from the free acid forms of each group to the monoanion form of each group was determined to be: 1.1, C-2; 1.5, C-1 and C-3; 2.1, C-4 and C-6; and 1.7, C-5. In the mono- to di-anion transition, the pKa values were: 6.85, C-2; 7.60, C-5; 5.70 and 12.0, C-1 and C-3; and 10.0, C-4 and C-6. These data and the appearance of the 31P hexaphosphate n.m.r. multiplet are discussed in terms of conformations of myo-inositol hexaphosphate.
| 4,222
|
Purification and properties of human acid-thermostable ribonucleases, and diagnosis of childhood pancreatic fibrosis.
|
Acid-thermostable ribonucleases were isolated from human pancreas, duodenal contents, liver, spleen, serum and urine, and purified 15--1000-fold. The pH optima, ionic requirements, and some of the specificity requirements, of these enzymes were investigated. The isolated enzymes formed two distinct groups: (a) The ribonucleases of the pancreas, duodenal contents and fraction A of serum and urine exhibit a pH optimum of 8.5, are inhibited by An2+ and Cu2+, and relatively rapidly hydrolyze the synthetic substrate uridine 3'-(alpha-naphthylphosphate); (b) the ribonucleases of the liver and spleen, and of fractions B of the serum and urine, with a pH optimum of 7, are less sensitive to An2+ and Cu2+, and exhibit negligible activity versus uridine 3'-(alpha-naphthylphosphate). Determination of the serum level of pancreatic-type ribonuclease activity, with the use of uridine 3'-(alpha-naphthylphosphate) or RNA as substrates, appears to be a valid diagnostic tool for pancreatic fibrosis in children.
| 4,243
|
Physico-chemical and immunological properties of acid alpha-glucosidase from various human tissues in relation to glycogenosis type II (Pompe's disease).
|
The physico-chemical and immunological properties of acid alpha-glucosidase from various human tissues have been studied. Heat stability of acid alpha-glucosidase from heart, liver and skeletal muscle is identical, but for kidney some different results are obtained. Identical isoelectrofocussing patterns are found for heart, liver and skeletal muscle. Furthermore, the effect of antiserum against human liver acid alpha-glucosidase on the activity of acid alpha-glucosidase from various tissues is studied. The results are discussed in relation to glycogenosis type II (Pompe's disease).
| 4,245
|
Assessment of the therapeutic effect of epimestrol and epimestrol associated with clomiphene in female sterility.
|
In 24 women with disturbances of ovulation treated for sterility with Epimestrol, ovulation was achieved in 3 patients but none of these became pregnant after therapy. Since it has been suggested that the association of Clomiphene with a weak estrogen might improve the pregnancy rate, we decided to administer Clomiphene associated with Epimestrol. Using this combined therapy in 58 patients, 32 out of the 58 women ovulated and 17 conceived. The overall rate of pregnancy using the combined therapy was no better than that obtained when Clomiphene alone is administered. From this study it is concluded that: (1) Epimestrol is not an effective method for the induction of ovulation, and (2) addition of Epimestrol to Clomiphene is of no clinical benefit.
| 4,384
|
Improvement of fertility and semen quality in men treated with a combination of anticongestive and antibiotic drugs.
|
The effects of a combined therapy of antibiotics and antiinflammatory drugs was evaluated in 344 men referred to our clinic for treatment of infertility. Physical signs of congestion, usually not severe, were detected in 244 men. The treatment caused significant improvement in semen quality, especially in sperm concentration, morphology and motility. Forty percent of the wives became pregnant. There was a striking relationship between increase in morphologically normal spermatozoa and incidence of pregnancy. It is speculated that the therapy had its major effect at the level of the epididymis and/or testis.
| 4,385
|
Hypogastric carotid bypass for Takayasu's disease.
|
Two cases of Takayasu's disease are presented which were successfully resolved by a Dacron graft from the right hypogastric artery to the right internal carotid artery. We recommend this bypass procedure of connecting the hypogastric artery to one of the aortic branches. Medical treatment with antibiotics, steroids and anti-coagulants has not been satisfactory.
| 4,405
|
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