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Preliminary characterization of bovine pineal prolactin releasing (PPRF) and release-inhibiting factors (PPIF) activity.
Bovine pineal glands were subjected to extraction with dilute acetic acid, gel filtration on Sephadex G-25 and subsequent ultrafiltration through Diaflo membranes PM10, UM2 and UM05. Various fractions derived at each step were tested for the presence of substances which stimulate or inhibit prolactin secretion in vitro and in vivo. Both prolactin releasing (PPRF) and release-inhibiting (PPIF) activities were observed. PPRF activity was present in certain fractions derived from Sephadex G-25 and in the PM10 residue (MW congruent to less than 10,000). Whereas both the UM2 residue (MW greater than 1000) and UM05 filtrates (MW less than 500) was seen to inhibit pituitary prolactin release in vitro, the UM05 residue (MW greater than 500 and less than 1000) inhibited prolactin release in vivo, possibly by stimulating the secretion of the hypothalamic prolactin inhibiting factor. On the basis of its inactivation by trypsin it was concluded that PPIF may be a peptide or contain a peptide moiety indispensible for its biological activity. Experiments are in progress to characterize pineal prolactin-regulating activities and to elucidate further the physiological role of the pineal gland in the regulation of prolactin secretion.
0.919247
Interactions of parenteral solutions with sulphur-treated glass bottles.
Concern about limited surface durability has been the main reasons for recommendations by advisory committees and government health authorities, not to reu-use sulphur-treated soda-lime glass (type II) bottles for intravenous solutions. In order to contribute specific data, the interactions of slightly acid and neutral parenteral solutions with ammonium sulphate-treated type II glass bottles have been investigated. It was established that the amounts of silica, sodium and calcium released into the solution are not greater than the potential background contamination from the raw materials. The number of particles in the solution was well below the limits set by the British Pharmacopoieia and not much higher than the lowest background count practically achievable. On an average, bottle surfaces released less material after the first time of use. Bottle-to-bottle variations revealed by scanning electron microscopy point at problems in achieving smooth, evenly surface-treated bottle surfaces during bottle manufacture.
0.88292
Urinary excretion of chlorpheniramine and pseudoephedrine in humans.
A specific high-pressure liquid chromatographic method for the determination of chlorpheniramine and pseudoephedrine in urine was developed and applied in a urinary excretion study of normal healthy subjects who received a sustained-release dosage form contianing 8 mgof chlorpheniramine maleate and 120 mg of pseudoephedrine hydrochloride. Five subjects received one dose on Day 1, followed by multiple dosing every 12 hr for 7 days without ammonium chloride administration. Four subjects received one dose of the sustained-release dosage form together with ammonium chloride. Urine samples were collected during the 1st day and at steady state. The method is specific and simultaneously determines choorpheniramine, two metabolites (mono- and di-desmethylchlorpheniramine), pseudoephedrine, and norpseudoephedrine. The assay recovery was less than 97% (0.06-3 microgram/ml) for chlorpheniramine maleate and less than 98% (1.5-75 microgram/ml) for pseudoephedrine hydrochloride. Excretion of chlorpheniramine and its two metabolites in urine was enhanced after ammonium chloride administration. At steady state, a change in urine pH from 5.69 to 6.46 resulted in more than a 25% decrease in chlorpheniramine and monodesmethylchlorpheniramine excretion. In spite of expected changes in its biological half-life, the overall amount of unchanged pseudoephedrine excreted in urine was not affected by urine pH, presumably because it is primarily excreted in urine as intact drug.
0.929496
Characterization of an immune complex kinase in immunoprecipitates of avian sarcoma virus-transformed fibroblasts.
Kinase activity detected in immune complexes containing the src gene product of the avian sarcoma virus has been reported. To further characterize this immune complex kinase, we developed a routine quantitative assay involving trichloroacetic acid precipitation on filters. The enzyme reaction required either Mg2+ or Mn2+, but was inactive with Ca2+. The kinetics of the phosphorylation reaction indicated a transient enzyme activity limited by rapid substrate-dependent inactivation of the enzyme. A variety of nucleoside and deoxyribonucleoside triphosphates (dATP, ATP, GTP, CTP, dGTP, TTP, dCTP) served as phosphoryl donors. The phosphorylation of immunoglobulin G was inhibited by the presence of nucleoside diphosphates. Deoxyribonucleoside diphosphates can either stimulate or inhibit the kinase reaction depending upon the concentration used. The unusual enzymatic properties of the immune complex kinase raise the possibility that the enzyme does not function as a protein kinase in vivo, but rather belongs to a different class of kinases (nucleotide kinases) which adventitiously phosphorylates immunoglobulin G when immunoprecipitated with immune serum.
0.841673
Isolation and characterization of phospholipase D from fababeans.
An enzyme activity in crude extract of fababeans hydrolyzed phosphatidylcholine-U-14C to produce choline and phosphatidic acid. This enzyme, phospholipase D, was stable at 50 C in the presence of 5 mM DTT but was inactivated at 55 C. The enzyme was precipitated with cold acetone, concentrated between 30% saturation to 40% saturation with ammonium sulphate, absorbed on calcium phosphate gel and eluted with 0.2 M phosphate buffer. This procedure resulted in a 20-fold increase in specific activity. The activity of fababean phospholipase D was much higher when assayed at 38 C than that at room temperature. There was an obligatory requirement for calcium, and for maximal activity 40 mM calcium was required. A narrow pH optimum of about pH 5.7 was observed. The enzyme activity was extremely dependent on substrate dispersion. When 5 mM phosphatidylcholine (PC) was sonicated with increasing levels of sodium dodecyl sulphate (1 mM to 4 mM), the enzyme activity kept increasing. By using equimolar concentrations of PC and sodium dodecyl sulphate (1 mM to 5 mM), the Michaelis constant (Km) was estimated to be 1.74 mM. Addition of choline and serine at 10 mM concentration reduced phospholipase D activity by 31% and 22%, respectively.
0.87605
Evolution of enzyme structure.
Three-dimensional structures of enzymes offer evidence about their evolution. There are clear examples of divergent families (e.g. mammalian serine proteases) and convergence (e.g. chymotrypsin and subtilisin). Topological similarities in dehydrogenases may reflect an ancient divergence or merely chemical constraints on protein architectures. Further experimental evidence is desirable to back up arguments based on molecular morphology. By growing microorganisms on novel foodstuffs in a chemostat, one can focus selective pressure on a specific enzyme activity. Experiments will be described in which such pressure is focused on pentitol metabolism. Examination of the fine structure of the genes responsible for this pentitol metabolism has given clues about the volution of metabolic pathways.
0.814494
Comparison and adaptation.
It has sometimes been suggested that the term adaptation should be reserved for differences with a known genetic basis. We argue that adaptation should be defined by its effects rather than by its causes as any difference between two phenotypic traits (or trait complexes) which increases the inclusive fitness of its carrier. This definition implies that some adaptations may arise by means other than natural selection. It is particularly important to bear this in mind when behavioural traits are considered. Critics of the 'adaptationist programme' have suggested that an important objection to many adaptive explanations is that they rely on ad-hoc arguments concerning the function of previously observed differences. We suggest that this is a less important problem (because evolutionary explanations generally claim some sort of generality and are therefore testable) than the difficulties arising from confounding variables. These are more widespread and more subtle than is generally appreciated. Not all differences between organisms are directly adapted to ecological variation. The form of particular traits usually constrains the form of value that other traits can take, presenting several obstacles to attempts to relate variation in morphological or behavioural characteristics directly to environmental differences. We describe some of the repercussions of differences in body size among vertebrates and ways in which these can be allowed for. In addition, a variety of evolutionary processes can produce non-adaptive differences between organisms. One way of distinguishing between these and adaptations is to investigate adaptive trends in phylogenetically different groups of species.
0.752221
Effect of experimental hydrothorax on the cough reflex in conscious cats.
The authors induced experimental hydrothorax in cats by injecting dextran into the pleural cavity under brief N2O anaesthesia. They examined the parameters of cough -- elicited by mechanical stimulation of the airway mucosa -- and blood gas and pH values under normal conditions and after the injection of 50, 100, 200 and 250 ml dextran. The tests were always performed 30 min after terminating anaesthesia, i.e. in conscious animals. The free fluid in the thorax was found, in conscious cats, to reduce the inspiratory values of cough, but to have no effect on cough expiration. This is in agreement with previous findings showing that the intensity of a cough expiration does not always depend on the intensity of the preceding cough inspiration. According to this finding, the decrease in the expiratory values of cough observed during experimental pleurisy cannot be due to the actual exudate. In cats, experimental hydrothorax in doses of 200 and 250 ml leads to respiratory insufficiency. The authors further found that, for the study of interoception in the airways of conscious cats, which requires experimental induction of pathological conditions under brief anaesthesia, nitrous oxide is a convenient anesthetic.
0.881874
Effect of ionic strength on the interaction of androgens with Sertoli cell nuclei.
Only 35-50% of the label accumulated after incubation of cultured Sertoli cells with 3H-testosterone was readily extractable with 0.4 M KCl during a 1 h exposure. The degree of extractability was relatively constant over the pH range 7.0-8.5 but could be increased by prolonged (15 h) exposure. While 0.1 M KCl extracted a measurable amount of label, 0.4 M KCl was significantly more efficient. Furthermore, a higher proportion of the material extracted with 0.4 M KCl was associated with macromolecular species. After a 45 min exposure to 3H-testosterone, the nuclear fraction contained primarily labeled testosterone and its 5 alpha-reduced metabolites. The relative distribution of these metabolites between salt-resistant and readily extractable forms varied between experiments. In contrast, 3H-R1881 (17 beta-hydroxy-17-methylestra-4,9,11-trien-3-one) remained essentially intact in the nuclear fraction but also was only 35% extractable with 0.4 M KCl. In conclusion, although the quantitative aspects of salt extractability appear to depend to some extent upon the extraction conditions, it is apparent that the Sertoli cell nuclear fraction accumulates a significant amount of androgen in a form which is relatively resistant to removal with 0.4 M KCl. The biological significance of this phenomenon remains to be established.
0.84661
Ultrastructure of testicular biopsy from an XX male.
Ultrastructural study of testicular biopsy specimens from an XX male showed hyalinized seminiferous tubules and tubules containing only mature Sertoli cells. These cells possessed large lipid inclusions as well as microfilament bundles which were perpendicular to the basement membrane and parallel to one another. The basal lamina was thickened and composed of several parallel layers with myofibroblast layers between them. The interstitium showed nodular to diffuse Leydig cell hyperplasia. Four types of Leydig cells were found: 1) normal Leydig cells with crystals of Reinke; 2) cells with abundant microcrystalline inclusions as well as microfilaments and concentric cisternae of smooth endoplasmic reticulum; 3) vacuolated cells containing numerous large lipid droplets; 4) immature Leydig cells. The different ultrastructural abnormalities found in the Sertoli and Leydig cells might be considered as the histological expression of a tubular-interstitial dysgenesis which is reflected in the high levels of gonadotropins and low levels of testosterone.
0.82848
Electron microscopical studies on the genesis of white adipocytes: differentiation of immature pericytes into adipocytes in transplanted preadipose tissue.
In order to clarify the relationships between perivascular cells, capillaries and fat cells, with a special reference to the origin of fat cells, we have made a light and electron microscopical study on the developing epididymal adipose tissue of newborn to 5-week-old rats, and also on the differentiating, transplanted epididymal preadipose tissue from 6-day-old rats. Development of epididymal preadipose tissue progressed rapidly 6 or 7 days after birth. The preadipose tissue on the 5th day after transplantation consisted of differentiated areas with many mature fat cells, and of undifferentiated areas in which these cells were scanty. In the differentiated areas of developing epididymal preadipose tissue, both in situ and transplanted, many fat cells seemed to develop in the area immediately adjacent to growing capillaries, but cells intermediate between perivascular cells and preadipocytes were seldom observed. However, in undifferentiated areas of transplanted tissue, we found ultrastructural evidence that immature pericytes of capillaries can differentiate into preadipocytes.
0.877273
[Mechanism of the protective effect of antiserum against isologous aggregated mouse immunoglobulins in transplantation immunity].
The injection of antiserum against isogeneic aggregated mouse immunoglobulins prolonged the survival time of skin allografts in mice by 5-6 days. The study of the possible mechanisms of this phenomenon revealed that the injection of aggregated immunoglobulin antiserum decreased the ability of the lymphocytes of the animals receiving the antiserum to induce local "graft versus host" reaction and to proliferate in the blast transformation test in response to phytohemagglutinin treatment and in the mixed lymphocyte culture test. When added in vitro, the antiserum did not influence either the mixed lymphocyte, or the specific cytotoxic effect of immune lymphocytes, but stimulated 3H-thymidine incorporation into the suspension of lymphocytes incubated with syngeneic irradiated cells. The latter fact may be indicative of the mitogenic action of the antiserum. The analogy between the mitogenic action of the antiserum and that of nonspecific mitogens, such as concanavalin A and phytohemagglutinin which also show opposite effects in vivo and in vitro, is discussed. The conclusion has been made that the increase of the survival time of the skin allograft after the multiple injection of aggregated immunoglobulin antiserum was primarily due to its action on the recognizing and proliferative functions of T lymphocytes, and later due to an increase in IgG synthesis.
0.899677
Mechanistic studies with purified components of the liver microsomal hydroxylation system: spectral intermediates in reaction of cytochrome P-450 with peroxy compounds.
Recent investigations in this laboratory on the mechanism of action of liver microsomal cytochrome P-450 (P-450 LM) and its interaction with other components of the hydroxylation system are presented. Two electrophoretically homogeneous forms of the cytochrome, phenobarbital-inducible P-450 LM2 and 5,6-benzoflavone-inducible P-450 LM4, so designated according to their relative electrophoretic mobilities, were used in these studies. Phosphatidylcholine is required in the reconstituted enzyme system for rapid electron transfer from NADPH to P-450 LM, catalyzed by NADPH-cytochrome P-450 reductase, as well as for maximal hydroxylation activity with either molecular oxygen or a peroxy compound serving as oxygen donor to the substrate. The phospholipid facilitates the binding of both substrate and reductase to P-450 LM and apparently causes a structural change in the cytochrome as shown by an increase in alpha-helical content, determined by circular dichroic spectrometry. P-450LM3 and LM4 are one-electron acceptors under anaerobic conditions, in accord with previous potentiometric titrations and product yield data, but in disagreement with previous titrations with reducing agents. The cause for the discrepancy between the present and earlier results is not yet fully understood. Stopped flow spectrophotometry was employed to detect intermediates in the reaction of peroxy compounds with P-450LM2. With m-chloroperbenzoic acid the intermediate formed has absorption maxima at 375, 425, and 540 nm in the absolute spectrum and at 370, 436, and 540 nm in the difference spectrum (intermediate minus oxidized form). A study of the magnitude of the spectral change at various peracid concentrations indicated that with this oxidant the reaction shows a dependence resembling a binding curve. These and other experiments with various oxidants, including cumente hydroperoxide, suggest a reversible two-step mechanism according to the reaction: P-450 LM + oxidant equilibrium C equilibrium D, where C may be an enzyme-oxidant complex and D is a spectral intermediate of unknown structure. A scheme is proposed for the mechanism of action of P-450 LM based on these and earlier studies, including evidence from deuterium isotope experiments for the formation of a substrate carbon radical prior to oxygen transfer.
0.880951
An adenosine triphosphate dependent deoxyribonuclease with adenosine triphosphatase, activity from Bacillus cereus.
An adenosine triphosphate-stimulated deoxyribonuclease was purified to about 4200 fold from Bacillus cereus. The enzyme activity of the crude extract increased by a factor of about 5 after dialysis. One of the low molecular weight inhibitors of the crude extract was found to be inorganic phosphate. During enzyme purification two nucleases were identified. One of them was specific to denatured DNA and the other one degraded both denatured DNA and native DNA. The activity towards native DNA could be increased several times by ATP. Through all steps of purification the ATP-independent DNase always accompanied the ATP-dependent one and the ratio of their activity was found to be constant. The ATP-dependent DNase also possessed ATPase activity stimulated both by native and denatured DNA. The fact that ATPase was stimulated by DNA and went together with ATP-dependent DNase during purification suggests that these functions belong to the same enzyme complex. Maximal activity of ATPase had broader pH, Mg2+ and ATP concentration ranges than that of DNase. Cooperation of the two functions may be limited only to a narrow range of ATP concentration. Km for ATPase was 1.6x10-4 M ATP.
0.858834
Isolation and characterization of influenza A viruses from wild ducks in northern Japan: appearance of HSW1 antigens in the Japanese duck population.
Twenty-six influenza A viruses were isolated from cloacal and tracheal samples of 235 resident and 396 migratory ducks in Miyagi prefecture, Japan, in 1977--78. Of these, twelve were antigenically related to the avian-origin HSW1 virus, A/duck/Alberta/35/76 (HSW1N1), but their neuraminidase antigens were characterized as Nav2-3, Nav4 or N2. These antigenic configuration have not previously been reported. In addition, one strain in which the neuraminidase antigen was identified as Nav4, was demonstrated to be a mixture of two haemagglutinins, HSW1 and Hav7. Two distinct strains were separated from the mixture and characterized as HSW1Nav4 and Hav7Nav4. The antigenic identification of an additional 13 influenza A viruses revealed the presence of six haemagglutinin subtypes (Hav1, Hav3, Hav4, Hav6, Hav7, and Hav8) and five neuaraminidase subtypes (Nav1, Nav2-3, Nav4, Neq2, and N2) in various combinations. The results suggest that the avian influenza A viruses among feral ducks may be isolated in various combinations of haemagglutinins and neuraminidase subtypes in Japan, and that feral ducks may be the site of genetic recombination occurring as a result of dual infection with different subtypes of influenza A virus.
0.913404
The effects of H1 and H2 antihistamines on histamine inhalation challenges in asthmatic patients.
This study was designed to examine the effect of an H1 antihistamine, chlorpheniramine, an H2 antihistamine, cimetidine, and the combination of chlorpheniramine and cimetidine on histamine-induced bronchoconstriction in a double-blind, randomized protocol on 11 patients with asthma. Each patient underwent a histamine inhalation challenge on 5 separate days. After a control day, histamine inhalation challenges were performed 2 h after the administration of a single oral dose of 8 mg of chlorpheniramine, 300 mg of cimetidine, the combination of chlorpheniramine and cimetidine, or placebo. Baseline pulmonary function measurements were not significantly altered by the 4 treatments. Body plethysmography data and measurements from the forced vital capacity maneuver were obtained before and after the histamine inhalation challenges. The provocation dose of histamine that produced a 20% decrease in forced expiratory volume in one second, a 35% decrease in mean forced expiratory flow during the middle half of the forced vital capacity, and a 50% decrease in specific airway conductance was significantly increased after administration of chlorpheniramine (p less than 0.002) and decreased after administration of cimetidine (p less than 0.02), where as no significant effect was noted after the combination of chlorpheniramine and cimetidine. The results suggest the presence of both H1 and H2 receptors in the airways of asthmatic patients.
0.878983
[Solubility and the complex-forming properties of the zwitterlytes, 6-aminopenicillanic and 7-aminodesacetoxycephalosporanic acids].
Relation between solubility of the zwitterlites 6-aminopenicillanic acid (6-APA) and 7-aminodesacetoxycephalosporamic acid (7-ADCA) and the ionic strength and pH of the solution was studied. A specific effect of benzylpenicillin (BP) and 7-phenylacetamidodesacetoxycephalosporanic acid (7-PADCA) on solubility of the above zwitterlites was found and complex formation was suggested. An explanation of the complex formation mechanism and a method for estimation of the instability constants of the complexes are presented. The method is based on determination of the changes in the zwitterlite solubility in the presence of the complex forming compound. The values of the characteristic solubility of the ampholyte zwitter ions and the instability constants of the complexes "zwitterlite-complex forming compounds" were determined. A mathematical description of the relation between the zwitterlite solubility within a wide range of pH and concentrations of the complex forming compounds is presented. Coincidence of the calculated and experimental data was observed, which provided a supposition that the substances involved in complex formation were charged.
0.90946
Application of fine-needle aspiration biopsy for the diagnosis of dysplastic and neoplastic liver cell changes induced by N-nitrosomorpholine in rats.
Male rats were treated with the hepatocarcinogen, N-nitrosomorpholine (NNM, 10 mg ad 100 ml drinking water) for 19 weeks. Repeated fine-needle aspiration biopsies of the liver were performed percutaneously. Cytomorphologic and cytochemical criteria were used for the characterization of dysplastic and carcinoma cells. The alterations seen in the smears were correlated with histopathologic findings in the punctured liver lobes. Cells showing type I dysplasia were recognized in smears obtained from day 7 on. They corresponded to the swollen, glycogen-free cells developing in zone 3 of the Rappaport acinus during the early treatment phases. In later stages type I dysplastic cells were observed in smears. This coincided with the development of neoplastic nodules seen in histopathologic preparations. Carcinoma cells were recognized first after 15 weeks. Marked gamma-glutamyl transpeptidase (gamma-GT) activity could be demonstrated cytochemically in biopsy smears and biochemically in biopsy homogenates during the early phases of NNM-treatment. Simultaneously, a rise in gamma-GT activity was also observed in the serum.
0.884948
Stimulation of phosphatidylinositol turnover in various tissues by cholinergic and adrenergic agonists, by histamine and by caerulein.
Studies are reported of the biochemical and pharmacological characteristics of the stimulation of phosphatidylinositol metabolism that is produced in appropriate target tissues by stimulation of various receptors that use Ca(2+) as their second messenger. (1) Muscarinic cholinergic and alpha-adrenergic phosphatidylinositol responses were observed in rat lacrimal gland, and a response to caerulein was detected in the longitudinal smooth muscle of guinea-pig ileum. (2) The muscarinic cholinergic phosphatidylinositol response of rat lacrimal gland, like that of several other tissues, is not dependent on the availability of extracellular Ca(2+). (3) Three phosphatidylinositol responses, namely to histamine in guinea-pig ileum smooth muscle, to alpha-adrenergic stimulation in rat vas deferens and to muscarinic cholinergic stimulation in rat lacrimal gland, were all found to involve phosphatidylinositol breakdown. (4) The stereospecificity of the muscarinic receptor responsible for the phosphatidylinositol response of guinea-pig pancreas was tested by using the two stereoisomeric forms of acetyl-beta-methylcholine; the S-isomer was very much more active than the R-isomer in provoking both phosphatidylinositol breakdown and its labelling with (32)P, as it is in provoking other physiological responses such as contractility or secretion. (5) Pilocarpine, a muscarinic partial agonist, provoked a significantly smaller phosphatidylinositol breakdown in rat parotid fragments than did carbamoylcholine, a potent muscarinic agonist. (6) All of these results are consistent with, but do not prove, a previously offered hypothesis that suggests that phosphatidylinositol breakdown is a reaction essential to stimulus-response coupling at a variety of cell-surface receptors that mobilize Ca(2+) from and through the plasma membranes of target tissues.
0.88965
Antihypertensive effect of intravenously and orally administered bunitrolol (Kö 1366).
1. Hypotensive effect of O-[3-(tert, butylamino-2-hydroxypropoxy]-benzonitrile hydrochloride (bunitrolol, Kö 1366) was examined by intravenous administration of 5 mg to 20 cases of essential hypertension and by longterm oral administration of 15-30 mg to 27 cases of essential hypertension. 2. It was found that bunitrolol given either i.v. or p.o., produced a significant decrease of systolic, diastolic and mean blood pressure at rest. 3. Inhibitory effect of bunitrolol on exercise-induced increase of blood pressure was remarkable, while there was little inhibitory effect on the cold pressor-induced one. 4. Bunitrolol decreased blood pressure and lowered plasma renin activity in high renin hypertensive patients, suggesting that the hypotensive mechanism based, at least in part, on its capacity of inhibiting renin secretion. 5. However, the main hypotensive mechanism of bunitrolol seemed, in the case of i.v. use, related to the cardiac inhibitory action. Regarding the hypotensive mechanism of this drug in the long-term use, further investigation will be required.
0.885487
Studies on the subunits of Escherichia coli coenzyme A transferase. Reconstitution of an active enzyme.
The alpha and beta subunits of the acetyl-CoA:acetoacetate-CoA transferase were purified by isoelectric focusing of the enzyme in the presence of 6 M urea. The purified beta subunit, in which the active center of the enzyme is located, exhibits low catalytic activity (2% of the specific activity of the native enzyme) which is stimulated 5-6-fold in the presence of an equimolar concentration of alpha subunit. The presence of the substrate,acetoacetyl-CoA, is required to recover the catalytic activity of the beta subunit and mixtures containing purified alpha and beta subunits. When the enzyme is dissociation in the presence of 6 M urea and the subunits are not fractioned, removal of the urea by dialysis results in the recovery of 88-98% of enzymic activity and the native alpha2beta2 subunit structure. However, analysis of this renatured enzyme by immunochemical techniques shows that the enzyme does not refold to a completely native conformation. This renatured enzyme exhibits an immunological reactivity more closely resembling the isolated alpha subunit. The results indicate that the alpha subunit serves as a structural subunit, or possible a maturation subunit, imposing a conformation on the beta subunit that is catalytically more competent.
0.83272
The formation and thermal stability of in vitro assembled fibrils from acid-soluble and pepsin-treated collagens.
The role of the non-helical regions of the collagen molecule in fibrillogenesis has been investigated by comparing the kinetics of fibril formation of pepsin-treated acid-soluble collagen, acid-soluble collagen and mixtures of the two and by comparison of the thermal stabilities of the fibrils formed. The acid-soluble collagen was found to aggregate more rapidly than the pepsin-treated collagen under physiological conditions of pH and ionic strength. Variations in ionic strength, at physiological pH, were found to have differing effects on the aggregation of these two forms of soluble collagen. Fibrils formed from the pepsinized-collagen had a lower thermal stability tha n those formed from the intact collagen. The behavior observed with mixtures of acid-soluble and pepsin-treated collagens was found to be quantitatively consistent with the pepsinized collagen being able to utilize the nuclei formed by the acid-soluble collagen for subsequent growth. However, the use of the acid-soluble nuclei by the pepsinized collagen for growth did not enhance its rate of precipitation during the growth phase, nor did it enhance the thermal stability of the fibrils formed from the pepsinized collagen.
0.887022
Presynaptic alpha-adrenoceptor blocking properties among tri- and tetra-cyclic antidepressant drugs.
1 The effect of various antidepressants (5 x 10(-8) to 2 x 10(-5) M) on the resting overflow of tritium, on the evoked overflow and the contractile response to electrical stimulation (2.5 Hz, 2.0 ms) has been determined in mouse vas deferens previously incubated with [(3)H]-(-)-noradrenaline.2 Mianserin and ORG GC 94 produced a concentration-dependent increase of more than two fold in the electrically evoked overflow and the contractile response and, at the highest concentration, slightly increased resting release. These effects were largely unchanged in the presence of a concentration of cocaine effective in blocking noradrenaline uptake (1.1 x 10(-5) M).3 The ability of phentolamine (1 x 10(-5) M) to increase both the evoked overflow of tritium and the contractile response was greatly reduced when these parameters were already elevated by the presence of mianserin or ORG GC 94.4 The inhibitory effect of exogenous (-)-noradrenaline on evoked overflow was greatly reduced in the presence of mianserin or ORG GC 94 (4 x 10(-6) M).5 The inhibitory effect of clonidine on the twitch response of the mouse vas deferens was antagonized by mianserin and ORG GC 94 in a competitive manner (pA(2) values 7.3 and 7.1 respectively).6 Maprotiline, desipramine and nortriptyline (> 3 x 10(-6) M) produced a parallel fall in both evoked tritium overflow and in the contractile response and increased the resting overflow at higher concentrations. These effects were largely unchanged in the presence of cocaine (1.1 x 10(-5) M).7 Doxepin, imipramine and iprindole all increased resting overflow at high concentrations (2 x 10(-5) M) but produced only small changes in evoked overflow and in the contractile response at lower concentrations.8 It is concluded that mianserin and ORG GC 94 produce a blockade of presynaptic alpha-adrenoceptors which could contribute to an antidepressant effect but that this type of action is not common to all antidepressants.
0.785069
Pharmacokinetic differences between single and multiple oral dosing with the guidance for beta-adrenoceptor blockade assessment.
The disposition profiles of a new beta-adrenergic-blocking drug, timolol, were investigated in healthy subjects after single oral doses, and in patients with mild or moderate essential hypertension given multiple doses. The t1/2 of timolol were different between the two groups, possibly due to the decreased plasma clearance after multiple administration. The dosage regimen calculations for patients indicated to receive the treatment for certain chronic diseases, should be determined by utilizing the disposition data obtained in steady-state conditions. The absolute reduction of exercise heart rate gave the best coefficient as a beta-blockade assessment. Applying a theory for translating the pharmacokinetics to the duration-action course of drug, pharmacokinetic t1/2 was proven to be much shorter than pharmacological t1/2. Timolol given on a twice-daily schedule has shown both antihypertensive effectiveness and plasma-renin-suppressing action in different subject. However, the casual relationship between the drug plasma level, blood pressure fall and change in PRA was not so clearly disclosed. The pharmacokinetics of beta-blockers, particularly with the property of receiving extensive metabolism by the mechanism of hepatic first-pass effect should be studied between single- and multiple-dosing schedules in subjects with diverse clinical conditions.
0.860581
Human amniotic fluid alpha-L-fucosidase.
The activity and properties of alpha-L-fucosidase in 24 samples of amniotic fluid have been investigated using the 4-methylumbelliferyl substrate. A wide range of fucosidase specific activity (0.20-1.45 nmol/min/mg protein) was found with an average value of 0.62 nmol/min/mg protein. Although no clear-cut correlation exist, there appear to be trends of decreasing fucosidase specific activity with increasing maternal age of donor and increasing gestational time. alpha-L-Fucosidase activity from four amniotic fluids was characterized kinetically and immunochemically and found not to differ in its properties due to maternal age of donor or gestational time. Isoelectric focusing revealed multiple forms between pH 5.0 and 6.8, with the majority of activity present between pH 5.0 and 6.0. The pH optimum is near pH 5.0 with a second optimum suggested at pH 6.2. The apparent Michaelis constant (Km) for the 4-methylumbelliferyl substrate is 0.05 +/- 0.01 mM. The enzyme is completely thermostable at 37 degrees C for at least 4 h but loses 95% of its activity after preincubation at 45 degrees C for 1 h. Double immunodiffusion and immunoprecipitation experiments using anti-liver alpha-L-fucosidase antibody suggest that the amniotic fluid alpha-L-fucosidase is antigenically similar, if not identical, to the human liver enzyme.
0.914017
Characterization and physiological function of rat renal gamma-glutamyltranspeptidase.
Rat renal gamma-glutamyltranspeptidase is an intrinsic membrane glycoprotein. The larger of its two subunits is apparently folded into two distinguishable domains which are separated by a protease-sensitive sequence of amino acids. Membrane binding of gamma-glutamyltranspeptidase results from the hydrophobic interaction of the nonpolar domain of the amphipathic subunit with the lipid bilayer. Localization of at least a portion of the gamma-glutamyl binding site on the smaller subunit limits the active site of the enzyme to one side of the membrane. Within the kidney, the enzyme is primarily associated with the luminal surface of the brush border membrane of the proximal straight tubule. Comparison of the kinetic properties of gamma-glutamyltranspeptidase with the pH and the substrates available within the tubular fluid suggests that the physiologically significant reaction catalyzed by the transpeptidase is the hydrolysis of glutathione and its S-derivatives. The glutathionemia and glutathionuria observed in a patient who lacks detectable gamma-glutamyltranspeptidase activity and in mice following specific inhibition of transpeptidase, support the hypothesis that the enzyme plays a major role in glutathione catabolism. It now appears that the activities attributed to the gamma-glutamyl cycle do not participate in amino acid transport, but instead constitute three separate metabolic pathways; the intracellular synthesis of glutathione, the intracellular degradation of gamma-glutamyl peptides and the extracellular hydrolysis of glutathione. The finding that various cells release reduced and oxidized glutathione indicates that glutathione turnover may be a process of intracellular synthesis, excretion and extracellular degradation.
0.875912
A pathway of polygalactosamine formation in Aspergillus parasiticus: enzymatic deacetylation of N-acetylated polygalactosamine.
1. An enzyme which hydrolyzes the acetamido groups of N-acetylgalactosamine residues in N-acetylated polygalactosamine was found in the supernatant fraction of Aspergillus parasiticus AHU 7165, a polygalactosamine-producing strain. 2. N-Acetylated polygalactosamine was used as a substrate in the purification and characterization of this enzyme. A 140-fold purification was obtained by means of ammonium sulfate fractionation followed by chromatography on carboxymethylcellulose and DEAE-cellulose. 3. The enzyme releases about 60-70% of the acetyl groups of N-acetylated polygalactosamine, giving a product with free amino groups. Whereas the enzyme also deacetylates oligosaccharides with 14 or more N-acetylgalactosamine units at a rate similar to that of deacetylation of the polymer, it deacetylates shorter oligosaccharides (trimer to hexamer of N-acetylgalactosamine) much more slowly and is virtually inactive toward disaccharide. Deacetylation can not be detected with bacterial cell wall peptidoglycan, N-acetylated heparin, partially O-hydroxyethylated chitin or monomeric N-acetylgalactosamine derivatives as substrates. 4. This enzyme shows double pH optima of 5.3 and 9.3. The Km value for N-acetylated poly-galactosamine is 0.15 g/l (or 0.54 mM with respect to monosaccharide residues). 5. The occurrence of this enzyme may account for the formation of polygalactosamine with free amino groups.
0.900308
Diazepam therapy in eclampsia.
The single drug therapy of diazepam can be introduced to effectively control convulsions in eclampsia. This treatment will have particular application in rural obstetrics where eclampsia is seen in severe form. The dose schedule of diazepam, as described in this study, shows the therapy to have a stabilizing effect on hypertension and pulse rate. It causes neither respiratory depression nor oliguria. Diazepam is an effective muscle relaxant. Its depressive effect on the newborn is in no way inferior to that of lytic cocktail therapy. The drug is readily available at low cost, even in the remote rural areas, and can be easily administered by any doctor or midwife.
0.882409
Modification of response of mouse neuroblastoma cells in culture by serum type.
The effect of various types of serum on morphological and biochemical changes in mouse neuroblastoma cells (clone NBP2) in culture was studied. The extent of spontaneous morphological differentiation varied markedly depending upon the type of serum and was maximal in agammaglobulin calf serum (CS). The extent of morphological differentiation after treatment of cells with cyclic AMP-stimulating agents was also dependent upon serum type and was least pronounced in fetal calf serum. The doubling time and extent of clumping varied with the type of serum. The activity of tyrosine hydroxylase (TH) in NB cells was dependent upon serum type and it was highest in newborn CS and agammaglobulin CS. Although elevation of intracellular levels of cyclic AMP in NBP2 clone invariably stimulates neurite formation and TH activity, these functions were increased in certain sera without a significant increase in the cellular cyclic AMP levels. The present study shows that neurite formation, growth rate and TH activity are regulated by more than one mode, one of which is mediated by cyclic AMP. The above changes are independently regulated in the sense that the expression of one can be increased in the absence of others.
0.859571
The effect of changes in endolymphatic ion concentrations on the tectorial membrane.
The development of a new preparation technique has allowed the effects of fluid-substitution experiments on the tectorial membrane (t.m.) to be studied morphologically and not only, as previously, electrophysiologically. The organ of Corti and t.m. were examined in situ, unfixed and with in vivo-like ionic conditions under light-microscopical control (differential-interference-contrast, magnification 400--800X). An irreversible shrinkage of the marginal and middle zones of the t.m. was observed under the influence of Na+ ions (substitution of endolymph with artificial perilymph). This shrinkage is also seen in specimens prepared for scanning electron microscopy after perfusion of scale media with perilymph. If endolymph is replaced by an isotonic solution of EDTA (ethylenediaminetetraacetate) the t.m. can swell in its vestibulo-tympanal extent, e.g. from 39 to 72 microns. This swelling is reversible on addition of CaCl2. Although the size of the t.m. is not influenced to any great extent by changes in fluid osmolarity, reduction of H+ ion concentration leads to a minimal state of hydration of the protobril system at pH 4.3 (i.e. region of isoelectric point). The mechanism of Na+ and Ca2+ effects are discussed. These results indicate that the subtectorial space is morphologically separated from the scala media proper by the marginal zone.
0.868226
Manganese, an essential trace element for N2 fixation by Rhodospirillum rubrum and Rhodopseudomonas capsulata: role in nitrogenase regulation.
Nitrogenase (N(2)ase) from the photosynthetic bacterium Rhodospirillum rubrum can exist in two forms, an unregulated form (N(2)ase A) and a regulatory form (N(2)ase R), the latter being identified in vitro by its need for activation by a Mn(2+)-dependent N(2)ase activating system. The physiological significance of this Mn(2+)-dependent N(2)ase activating system was suggested here by observations that growth of R. rubrum and Rhodopseudomonas capsulata on N(2) gas (a condition that produces active N(2)ase R) required Mn(2+), but growth on ammonia or glutamate did not. Manganese could not be shown to be required for the biosynthesis of either nitrogenase or glutamine synthetase or for glutamine synthetase turnover, but it was required for the in vitro activation of N(2)ases from N(2) and glutamate-grown R. rubrum and R. capsulata cells. Chromatium N(2)ase, in contrast, was always fully active and did not require Mn(2+) activation, suggesting that only the purple nonsulfur bacteria are capable of controlling their N(2)ase activity by this new type of regulatory system. Although R. rubrum could not substitute Fe(2+) for Mn(2+) in the in vivo N(2) fixation process, Fe(2+) and, to a lesser extent, Co(2+) could substitute for Mn(2+) in the in vitro activation of N(2)ase. Electron paramagnetic resonance spectroscopy of buffer-washed R. rubrum chromatophores showed lines characteristic of Mn(2+). Removal of the Mn(2+)-dependent N(2)ase activating factor by a salt wash of the chromatophores removed 90% of the Mn(2+), which suggested a specific coupling of this metal to the activating factor. The data presented here all indicate that Mn(2+) plays an important physiological role in regulating the N(2) fixation process by these photosynthetic bacteria.
0.889728
A neutral proteinase of monkey liver microsomes. Solubilization, partial purification, and properties.
Conditions for the solubilization of membrane-bound neutral proteinase associated with monkey liver microsomes were investigated. Among the reagents tested, deoxycholate, cholate, and some nonionic detergents, including Triton X-100, with hydrophilic-lipophilic balance values of around 13, were effective. The solubilization profile indicated that the enzyme is bound to the microsomal membranes by strong hydrophobic interaction. The enzyme was partially purified from monkey liver microsomal fraction, previously washed with 1 M KCl and 0.05% sodium dodecyl sulfate, by Triton X-100 extraction, followed by chromatography on columns of hydroxylapatite and Sepharose CL-6B. The apparent molecular weight of the enzyme was estimated to be about 88,000 from the elution position on Sepharose CL-6B column chromatography in the presence of 0.5% sodium cholate. It was optimally active at pH 8.0 with heat-denatured casein as a substrate. It was strongly inhibited by diisopropyl phosphorofluoridate and phenylmethanesulfonyl fluoride, indicating that the enzyme is a serine proteinase. EDTA, EGTA, and chymostatin also inhibited the enzyme strongly. Among urea-denatured protein substrates tested, calf thymus histone was hydrolyzed most rapidly, followed by casein, hemoglobin, and bovine serum albumin, whereas practically no hydrolysis occurred with denatured ovalbumin, fibrinogen, and gamma-globulin as substrates.
0.896324
Anatomy and ultrastructure of the axons and terminals of neurons R3-R14 in Aplysia.
Using light and electron microscopy and autoradiography, we have traced the axons of neurons R3-R14 in the parietovisceral ganglion (PVG) of Aplysia to terminal fields associated with vascular tissue. The axons are identified by their large size (15-30 micrometer diameter), extensive glial infolding, characteristic dense core vesicles (DCV; approximately 180 nm diameter), and specific, rapid uptake of 3H-glycine. Each neuron in this homogeneous group sends an axon via the branchial nerve to the pericardial region surrounding the junction of the efferent gill vein and the heart. R14 also sends axons to major arteries near the PVG. The R3-R14 axons branch extensively; we estimate that there are at least several hundred per cell. Branches along axons in the branchial nerve exit the nerve, subdivide, and end blindly in the sheath which is bathed by hemolymph. Similar blind endings from R3R14 occur in the sheath of the PVG (Coggeshall, '67). Axonal branches in the pericardial region and the special R14 axons in the arterial walls form both varicose endings near and terminals in contact with vasvular smooth muscle. All R3-R14 endings are free of glia, packed with DCV, show occasional omega-shaped profiles and rapidly take up 3H-glycine. R3-R14 manufacture specific low molecular weight peptides (Gainer and Wollberg, '74), and both the cell bodies (Iliffe et al., '77) and the germinals contain unusually high concentrations of glycine. The presence of peptides as putative neurohormones and sheath endings (neurohormonal release areas) are consistent with R3-R14 being neurosecretory (Coggeshall et al., '66). While glycine could not be a circulating hormone due to its high circulating levels (Iliffe et al., '77), glycine could act as a local chemical messenger between R3-R14 and smooth muscle. The terminal morphology of R3-R14 is consistent with these neurons having both synaptic-type and neurosecretory-type functions.
0.863349
Phenotypically determined resistance of Neisseria gonorrhoeae to normal human serum: environmental factors in subcutaneous chambers in guinea pigs.
Some gonococci obtained from human urethral exudate or from subcutaneously implanted chambers in guinea pigs show a resistance to killing by human serum which is lost on sub-culture in vitro after a few generations. The environmental factors which may influence the phenotypic expression of resistance to serum killing were investigated in guinea pig chambers and in chamber fluid in vitro. The redox potential in chambers before and after infection was lower than that of heart blood but conditions were not anaerobic; H2O2 increased the redox potential but did not decrease gonococcal serum resistance. The chambers were slightly alkaline before and after infection. When the concentration of glucose (depleted in infected chambers by the abundant polymorphonuclear cells) was restored to excess, the serum resistance of the gonococci was unaffected. Concentrations of free amino acids in chambers changed little during infection. Gonococci adapted to growth in chambers and subsequently rendered serum-sensitive by growing once on agar reverted to serum-resistance after 0.5 to 1 h incubation in chamber fluid in vitro at 37 degrees C but not at 25 degrees C or 4 degrees C. After 16 to 24 h growth at 37 degrees C, resistance was again lost. The reversion to serum resistance did not occur in a complex laboratory medium. Examination of the chamber fluid after growth of gonococci in vitro showed depletion of lactate, glutamine and proline.
0.882621
Studies on the mechanism of action of acetylcholine antagonists on rat parasympathetic ganglion cells.
The mode of action of ACh antagonists on the parasympathetic neurones of the submandibular ganglion of the rat was studied by means of a two-micro-electrode voltage-clamp technique. The currents produced by various agonists (carbachol, ACh, suberylcholine) were studied in steady state and after voltage steps, before and after perfusion of various antagonists. 2. For three antagonists (tubocurarine, hexamethonium, decamethonium) the blocking action increases with hyperpolarization. For three other antagonists (surugatoxin, trimetaphan, mecamylamine) the effects observed at low concentrations appear to be independent of membrane potential, although in some cases voltage dependence of the block was observed for mecamylamine. 3. The blocks the 'open' channel-reception complex. The block produced by tubocurarine, hexamethonium and decamethonium increases with the agonist concentration, an observation which supports a 'sequential' scheme in which the antagonist blocks the 'open' channel-receptor complex. The block produced by trimetaphan and mecamylamine decreases slightly with increased agonist concentration, which in turn suggests that these two compounds are competitive antagonists, preventing binding of the agonists to the closed channel-receptor complex. 4. In the cases where the block is voltage dependent, voltage jumps trigger slow relaxations which are not present in control conditions. In the case of tubocurarine and hexamethonium, the relaxation following a hyperpolarizing voltage jump corresponds to a decrease in conductance. In the case of decamethonium, the slow relaxation is in the opposite direction. 5. The slow relaxations observed with tubocurarine and hexamethonium are speeded by an increase of the antagonist concentration; the slow relaxations observed with decamethonium are slowed by an increase of the decamethonium concentration. 6. The steady-state observations and the relaxations can be interpreted in terms of a scheme in which tubocurarine, hexamethonium and decamethonium act mainly by blocking the channels opened by the cholinergic agonists. 7. The two types of slow relaxation are those predicted if tubocurarine and hexamethonium dissociate slowly from the channel, and decamethonium rapidly. 8. An additional effect of tubocurarine is described, which consists of a potentiation of the rising phase of the response to an ionophoretic pulse. Possible mechanisms of this effect are discussed.
0.804228
Biological investigations in alcohol research.
The biological mechanisms examined in this paper cover only a small portion of those that may be involved in the pathogenesis of alcoholism. Certain areas on which a great deal of work has already been done have been entirely omitted. Among these are studies on brain acetylcholine and gamma-aminobutyric acid metabolism in alcohol-related conditions; the effect of alcohol on brain proteins and nucleotides and the relationship of changes in these to the development of tolerance and physical dependence; and a variety of other areas involving biochemical and physiological parameters. The omission of any of these areas in no way suggests that they are less significant than those that have been covered. It is just that I have attempted to present a cohesive and coherent review of some areas of biological research which thus far appear to throw light on the clinical development and phenomenology of the alcoholism syndrome. In order to present such a thesis, I have inevitably crowded the evidence to fit some of my pet hypotheses. However, in controversial areas (which are many), I have tried to present some of the evidence on both sides and, hopefully, have succeeded in offering a fair overview of the state of the science as it exists today.
0.824319
PCP (phencyclidine): an update.
The steady rise in the promiscuous use of phencyclidine (PCP) as a "recreational" drug has recently gained nationwide attention because of the numerous violent and/or bizarre incidents caused by the use of this drug. Because the media often exaggerate reports of bizarre and violent behavior to make a "good" story, the potential PCP user may be tempted to ignore the media warnings. In the case of PCP, however exaggerated the story, a real danger does exist. So, despite numerous newspaper, radio and television warnings about the possible consequences of PCP use and abuse, the incidence of toxic reactions continues to climb. In many cases PCP is sold as other drugs, particularly THC, and in various colored capsules, tablets, liquids and crystals which may explain the increased usage despite the numerous warnings against its use. The advances in laboratory techniques and chemical processess have enabled the clandestine chemist to prepare relatively pure PCP and thus eliminate many of the toxic side effects due to impurities in the drug. In addition, 30 or more psychoactive PCP analogues have been developed and are starting to make an appearance on the street. PCP is perhaps the most potent psychotomimetic compound known at the present time and is capable of inducing a psychosis which is clinically indistinguishable from schizophrenia. The psychosis-producing effects of PCP are the most common toxic effects seen in hospital emergency rooms; but as the amount of PCP taken and/or the simultaneous involvement of other drugs, particularly barbiturates, occurs, severe medical problems (e.g., coma, seizures, respiratory arrest) begin to appear. Death from high doses of PCP or PCP plus other drugs does occur, but the principal cause of death from PCP abuse is due to trauma, homicide or suicide (usually of the bizarre or violent form). Young adult males, persons predisposed to mental illness and naive drug users appear to be the most susceptible to the adverse effects of PCP. The fact that chronic PCP users are starting to increase in number is mute testimony that not all users experience "bad trips" with PCP. Unfortunately for the user, however, this does not guarantee that the next trip will not be a bad one. The effects of chronic use seem to be twofold: severe depression with suicidal thoughts and numerous violent, agitated behavioral patterns. Neither seems to be a suitable alternative. At the present time there is not specific antidote for toxic PCP reactions and the prolonged psychosis induced in some cases does not appear to respond to the standard antipsychotic medications as quickly as do the functional psychoses. The major improvement from a medical standpoint is the development of more sensitive laboratory techniques to confirm the presence of PCP in body fluids. This advance has undoubtedly led to the apparent increase in the number of PCP cases reported by hospitals and to the accuracy of clinical diagnosis by medical, drug or law enforcement communities...
0.785368
Digoxin induced release of creatine kinase from isolated guinea-pig hearts.
In isolated perfused guinea-pig hearts, digoxin produced a concentration dependent release of creatine kinase (ATP-creatine-transphosphorylase; CK). A corresponding decrease of the CK activity in the myocardium was obtained. The enzyme release seems to be a sign of glycoside intoxication, as its extent paralleled the severity of digoxin induced arrhythmias. Especially high CK activities were liberated when ventricular fibrillation occurred. Likewise, electrically induced fibrillation, in control hearts, led to enzyme release. However, the digoxin effect was not matched. Reserpine pretreatment antagonized the CK release by electrical fibrillation, whereas it increased excessively the enzyme liberating effect of higher digoxin concentrations. Also, propranolol decreased the enzyme release due to electrical fibrillation. The glycoside induced CK liberation, however, was not diminished, although the ventricular fibrillation was prevented. Increase of the potassium concentration of the perfusion fluid prevented the glycoside induced fibrillation, and reduced the enzyme release. The significance of the enzyme loss from the myocardium, and the mechanisms of enzyme release are discussed.
0.886141
[Bone marrow transplantation in severe aplastic anemia and acute leukemia].
Much progress has been made in allogeneic bone marrow transplantation for severe aplastic anemia (SAA) and acute leukemia (AL). In SAA it was shown that hemopoietic chimerism and apparently permanent cures can be achieved in the majority of patients by conditioning with cyclophosphamide followed by bone marrow transplantation (BMT) from an HLA-identical sibling. The previous transfusion history is crucial for failure or success: untransfused patients do very well while graft rejection is an enormous problem in most polytransfused ones. We have shown that most patients without HLA-identical sibling donors can be adequately helped as well. After conditioning with ALG followed by transfusion of haploidentical marrow and low dose androgens there is partial to complete autologous hemopoietic reconstitution in virtually all patients. This points to the fact that most of these patients have pluripotent hemopoietic stem cells that are intact, but apparently unable to differentiate to mature cells, because they are inhibited by autoimmune mechanisms. The results of BMT in patients with endstage leukemia are modest. New pilotstudies with early marrow grafts, i.e. for ANLL in first remission and for ALL in second remission indicate that with this type of approach potentially over 50% of all patients with HLA-identical siblings can be cured. We recommend that HLA-typing should be performed early in families with SAA and AL and that the possibility of a marrow graft should be seriously considered before the patients have endstage disease. Marrow grafts are technically simple but they may pose enormous problems such as graft versus host reaction (GvH), interstitial pneumonia, graft rejection and leukemic recurrence. Therefore, the procedure should only be performed in highly specialized centers with much knowledge and experience in the immunobiology of bone marrow transplantation.
0.847831
[Utilization of maltose during shorttime parenteral nutrition (author's transl)].
Twelve metabolically healthy patients, who had to undergo cholecystectomy or gastric resection, were fed intermittently by the parenteral route (via veins of the upper limbs) post-operatively up to and including the 2nd post-operative day with a combined maltose-glucose solution in parallel with an 8% mixture of crystalline L-aminoacids. At an administration rate of 150 g maltose/day and 250 g glucose/day with the simultaneous administration of 80 g aminoacids, the mean carbohydrate utilisation was 82,5%. The glucose and maltose levels in the blood fluctuated in accordance with the infusion periods and the free fatty acids levels measured were their mirror image. On the whole free fatty acids were lowered significantly, which indicates adequate carbohydrate supply with consequent inhibition of lipolysis. The degree of tolerance was determined objectively by measurement of the acid-base parameter, gamma-GT, alkaline phosphatase, GOT, bilirubin, uric acid, creatinine and serum electrolytes. No changes were found which could be attributed to the administration of the infusion solution.
0.838613
Prevention of genetic anemias in mice by microinjection of normal hematopoietic stem cells into the fetal placenta.
Mice homozygous for mutant genes at the W locus have a marked macrocytic anemia that is fatal in some genotypes. The defect is believed to originate in the developmentally pluripotent hematopoietic stem cell population. Anemia is first grossly manifest on day 13 of gestation, when the liver is the chief hematopoietic organ. The known paucity of blood-forming foci in livers of homozygotes and the limited formation of their erythrocytes suggested that such fetuses-unlike normal ones-might have conditions favorable for in utero seeding of genetically normal hematopoietic tissue. If this were accomplished before day 13, the anemia might essentially be prevented, or at least substantially mitigated, and normalcy soon achieved by cell selection. This proved to be the case. Allogeneic normal fetal liver cells were microinjected into the blood vessels of the fetal placenta on day 11 of gestation. Of eight mutant homozygotes born from segregating matings, six (four W/W, two W(v)/W(v)) were successfully populated with donor cells. Strain-specific hemoglobin markers demonstrated replacement of the erythroid lineage with the normal type, the rate of substitution being more rapid in the W/W (ordinarily more anemic) recipients. Strain-specific isozyme differences revealed that white blood cells were also replaced. Thus, the initial selective pressure, hence the W-mutant phenotypic lesion, must have occurred at the pluripotent stem cell stage. The animals remained immunologically tolerant of the donor cells and no graft-versus-host reaction occurred. The early introduction of hematopoietic cells differing genetically from all the other tissues of the animal provides possibilities for tracing normal hematopoietic lineages in vivo, for analyzing cell and tissue interactions, such as those between lymphocytes and thymus, and for clarifying the etiology of other blood or immune insufficiencies or malignancies.
0.84178
Higher molecular weight forms of immunoreactive somatostatin in mouse hypothalamic extracts: evidence of processing in vitro.
Extracts of mouse hypothalamus made in acid/urea containing protease inhibitors were analyzed for somatostatin immunoreactivity after molecular sieve filtration on Sephadex G-50. Higher molecular weight (higher-M(r)) somatostatin-like forms with apparent molecular weights of 15,000, 10,000, and 6000 could be identified, besides the molecular weight 1600 somatostatin. Immunological identities with somatostatin were unambiguously demonstrated by the analysis of the displacement curves in the radioimmunoassay. The M(r) 15,000, 6000, and 1600 species were purified by affinity chromatography on an anti-somatostatin immune serum covalent conjugate with Sepharose used as immunoadsorbant. After disulfide reduction by dithiothreitol, the size of the M(r) 15,000 and 6000 somatostatin-like species was assessed either by molecular sieve filtration or by polyacrylamide gel electrophoresis. The results indicated that the higher-M(r) somatostatin-like species isolated from the hypothalamus did not result from hormone polymerization by means of disulfide interchange. The processing in vitro of the 15,000 higher-M(r) form of somatostatin was achieved by proteolytic enzymes coeluted with this species during the fractionation of hypothalamic extracts. Under neutral pH conditions the intermediary higher-M(r) forms were generated together with the M(r) 1600 somatostatin-like species. This processing activity could be either strongly inhibited at acidic pH or in acid/urea medium or else eliminated by selective immunoadsorption of the 15,000 higher-M(r) form. Neither trypsin nor the gamma subunit of 7S nerve growth factor was able to produce this processing, suggesting that enzymes with other kinds of specificity may be involved. It is concluded that somatostatin biosynthesis in the mouse hypothalamus may occur via a high-M(r) precursor that is processed into intermediary forms leading to the tetradecapeptide hormone.
0.911652
Transport of gamma-glutamyl amino acids: role of glutathione and gamma-glutamyl transpeptidase.
This work relates to the hypothesis that one of the mechanisms that mediates amino acid translocation across cell membranes involves the action of membrane-bound gamma-glutamyl transpeptidase on intracellular glutathione and extracellular amino acids to form gamma-glutamyl amino acids. According to this idea, the latter are translocated into the cell where the gamma-glutamyl moiety is removed to yield free amino acids. Previous studies in this laboratory showed that intracellular glutathione is translocated out of many cells. We have now directly examined the transport of gamma-glutamyl amino acids into tissues in the mouse by use of the model substrate L-gamma-glutamyl-L-[14C]methionine sulfone. Of 11 tissues examined, only the kidney showed strong and preferential uptake of the substrate. A substantial amount of the administered L-gamma-glutamyl-L-[14C]methionine sulfone was found intact in the kidney; the total uptake of this compound was greater (by about 2-fold) than that of free L-methionine sulfone. Studies with a number of other gamma-glutamyl amino acids and gamma-glutamyl compounds indicate that the kidney has a relatively specific transport system for gamma-glutamyl amino acids. Small but significant amounts of gamma-glutamylmethionine sulfone were found in the liver and pancreas, suggesting that other tissues may also have this system. Transport of gamma-glutamylmethionine sulfone into the kidney was inhibited by inhibitors of glutathione synthesis and of gamma-glutamyl transpeptidase. The results suggest that both the transpeptidase and glutathione may be involved in transport of gamma-glutamyl amino acids.
0.910336
Oncofoetal antigens of human trophoblast.
Rabbits immunized with human trophoblast cell membranes produced antibodies that were detected, by immunofluorescence, to react with normal human tissues, and, by complement-mediated cytotoxicity, with several transformed human cell lines. Absorption with trophoblast abolished all of these reactions, whereas multiple absorptions with lymphocytes, liver or kidney failed to remove reactivity with either trophoblast or certain transformed cells. To further identify the antigens responsible for these antibodies, rabbits were immunized with a chromatographed fraction of deoxycholate-solubilzed membranes prepared from KCl-extracted, ultracentrifuge-prepared trophoblast microvilli. The resultant IgG antibody reacted specifically with syncytiotrophoblastic membranes in sections of human placentae, in addition to recognizing the membranes of viable Chang liver, AV3, HEp-2, Sw/156 (kidney) and Sw/527 (breast) cells. That normal tissues, baboon or monkey placentae, and HeLa or Daudi cell lines did not react with this antibody, indicates the presence of species- and organ-specific antigens in human trophoblast, as well as the existence of trophoblast cross-reactive antigens on some transformed cells. The selective localization of these antigens at the interface of the materno-foetal graft suggests that they function biologically in the host-parasite relation of human pregnancy; their appearance on many transformed cells implies a similar function in the host-parasite relation of some human cancers.
0.818165
Dual histamine receptor mechanism in guinea-pig lung.
Isolated guinea-pig lung parenchymal strips (GPLS) relaxed in response to the selective histamine H2-receptor agonists, dimaprit and 4-methylhistamine (4-MeH), and to low doses of histamine (10(-9) to 10(-7) mol/l) and contracted in response to several spasmogens. The order of the relative activity of the spasmogens was 2-methylhistamine (2-MeH) greater than histamine greater than carbachol greater than 2-pyridylethylamine (2-PE). Dimaprit and 4-MeH also relaxed GPLS which were contracted by 2-MeH, 2-PE or carbachol. Metiamide (a selective H2-antagonist: 5 x 10(-5) mol/l inhibited or reversed relaxations to histamine, dimaprit and 4-MeH, and significantly enhanced contractile responses to histamine without altering responses to carbachol. Mepyramine (a selective H1-receptor antagonist: 10(-8) to 10(-6) mol/l antagonized histamine-induced contractions. This investigation shows: (1) histamine is more active than carbachol in GPLS and (2) the occurrence of histamine H1-receptors mediating contraction and H2-receptors mediating relaxation in guinea-pig lung.
0.807771
Role of preload and inotropy in stroke volume regulation at constant heart rate.
The relationship between preload and inotropy on left ventricular function was studied in anaesthetized open-chest dogs, by measuring left ventricular dimensions and stroke volume before and during saline infusion at different levels of inotropy. Left ventricular dimensions were continuously estimated by recording myocardial chord length (MCL) in the anterior wall of the left ventricle by ultrasonic technique. The effects of isoproterenol, a stimulator of adrenergic beta-receptors (high inotropy), and propranolol, an inhibitor of adrenergic beta-receptors (low inotropy), were examined during right atrial pacing at constant heart rate averaging 161 +/- 5 beats/min. Stroke volume was varied within the range 9.0 +/- 1.7 ml to 28.6 +/- 3.2 ml by increasing inotropy and preload. To increase preload, saline was infused intravenously until end-diastolic MCL increased by about 10% and left ventricular end-diastolic pressure was higher than 10 mmHg. At constant heart rate and blood volume, both before and during saline infusion, end-diastolic MCL was not influenced by isoproterenol or propranolol administration. End-systolic MCL was reduced by raising inotropy. The difference between end-diastolic and end-systolic MCL, the systolic myocardial shortening (MS), increased during saline infusion; the relative increase in MS was the same at high and low inotropy. On average, MS was more than 50% longer at high than at low inotropy, both before and after saline infusion. Thus, left ventricular end-diastolic volume is increased by saline infusion and end-systolic volume is reduced by increasing inotropy. Preload and inotropy exert independent effects on stroke volume.
0.855981
Protein synthesis inhibition in rat liver by the mycotoxin patulin.
Patulin, a carcinogenic mycotoxin, inhibits in vivo and in vitro protein synthesis in rat liver. The in vivo inhibition culminates 5 h after toxin administration and reaches a maximum of 65% with regard to control values; a breakdown of polysomes is associated with the translational blockage. However in in vitro systems, the cellular fractions obtained from patulin-treated rats appear equally as active in protein synthesizing ability and as sensitive to the toxin action as those prepared from control animals. The in vitro inhibition by patulin is dose related. The postmitochondrial system is less sensitive than that functioning with isolated polysomes and pH 5 enzyme. This difference might be due to the presence of soluble factor(s) that counteract patulin action. We propose that the inhibition of protein synthesis by patulin may result from an interaction of the drug with active SH groups at the membrane level (amino acid transport, ion equilibrium) and/or at the cytoplasmic level (enzymes and factors involved in the translational process).
0.928387
Consequences of recurrent phosphate trapping induced by repeated injections of 2-deoxy-D-galactose. Biochemical and morphological studies in rats.
2-Deoxy-D-galactose, in a dose of 3 mmol/kg, was administered intraperitoneally twice daily to young rats for periods up to 12 weeks. This dosage schedule resulted in recurrent phosphate trapping predominantly in liver. UTP deficiency was excluded by simultaneous uridine injections. Phosphate trapping was caused by the rapid accumulation of 2-deoxy-D-galactose 1-phosphate and was most pronounced in liver but also demonstrated in small intestine, brain, spleen, and thymus. The marked, although transient, drop in the hepatic content of inorganic phosphate triggered the catabolism of adenine nucleotides and a loss of ATP. Other metabolic pathways affected by phosphate deficiency include glycogenolysis and glycolysis. Increasing with time, repeated doses of the galactose analog led to retardation and arrest of growth, hepatomegaly, and splenomegaly. The average relative liver and spleen weights were elevated 2.5- and 4.5-fold, respectively, after 12 weeks of treatment. Liver damage was indicated by hyperbilirubinaemia and a progressive rise in the activity in plasma of sorbitol dehydrogenase, alkaline phosphatase, and gamma-glutamyltransferase. Examination by light and electron microscopy showed increasing numbers of vacuoles, surrounded by a single membrane, in hepatocytes, sinusoidal endothelial cells, and Kupffer cells. Focal cytoplasmic degeneration in hepatocytes was occasionally indicated by formation of autophagic vacuoles and finger print lysosomes. Hepatocytes of 2-deoxy-D-galactose-treated rats showed a dissociation and fragmentation of the rough endoplasmic reticulum. Sinusoidal endothelial cells and Kupffer cells were markedly enlarged, the latter contained a PAS-positive but amylase resistant substance. Extrahepatic changes included an increased occurrence of vacuolated cells in thymus. Phosphate trapping and its metabolic consequences are common phenomena in the experimental injury induced b 2-deoxy-D-galactose and in some hereditary diseases such as uridylyltransferase deficiency galactosaemia, fructose intolerance and glucose-6-phosphatase deficiency.
0.900534
Stereological study of endoplasmic reticulum, Golgi complex and secretory granules in the B-cells of normal and alloxan-treated mice.
Different B-cell organelles (lamellar and vesicular endoplasmic reticulum, Golgi complex, whole secretory granules and secretory granule cores) were studied stereologically in pancreatic islets from control mice and mice killed 10 or 60 min following alloxan injection. Ten min following alloxan a significant decrease was observed in the volume, surface and numerical densities of whole secretory granules and their cores, and a significant increase was found in the volume and surface densities of vesicular endoplasmic reticulum. At the 60 min observation time, a significant decrease was seen in the volume density of lamellar endoplasmic reticulum and Golgi complex, and in the volume, surface and numerical densities of whole secretory granules and their cores, and a significant increase was observed in the volume and surface densities of vesicular endoplasmic reticulum, and in the mean values for volume and surface of whole secretory granules and their cores. The stereological data indicate swelling of endoplasmic reticulum, decreased Golgi area, and decreased number and total volume and surface of secretory granules during the first hour after alloxan administration to mice. The observations may be consistent with inhibited insulin synthesis.
0.909414
Effects of digoxin on isolated human peripheral arteries and veins.
In isolated human crural arteries and veins, digoxin induced slowly developing, long-lasting contractions. These contractions were not diminished by alpha-adrenoceptor blockade or by washing, but were abolished by the calcium antagonist nifedipine. In the presence of digoxin, the maximum contractile responses to noradrenaline (18 microM) and potassium (127 mM) markedly increased, and the glycoside shifted the noradrenaline concentration-response curve to the left. Immersion of vein preparations in calcium-free medium for 30 min. abolished the digoxin contraction, whereas responses could still be elicited by potassium and noradrenaline. A change of the extracellular potassium concentration from 4.6 to 6.9 and 9.2 mM caused relaxation, and a further increase to 13.8 mM contracted the preparations. After pretreatment with digoxin (1 micronM), a potassium change from 4.6 to 1.15 mM caused relaxation and all concentrations exceeding 4.6 mM produced contraction. It is concluded that digoxin has a direct contractile effect on isolated human crural vessels, and that this effect is dependent on the extracellular calcium concentration. In the presence of the glycoside, the responses to noradrenaline and potassium are potentiated. Vascular responses to changes in extracellular potassium concentration are influenced by digoxin.
0.866697
[Flunitrazepam-pretreatment for prevention of adverse cardiovascular effects following ketamine].
In 18 patients with documented ischaemic heart disease the cardiovascular effects of ketamine (1.5 mg/kg iv) were studied under three different conditions: 1. in awake premedicated patients (n = 6); 2. after the previous administration of flunitrazepam (0.015 mg/kg iv, n = 6) and 3. under conditions of neuroleptanalgesia and muscle relaxation (n = 6). Flunitrazepam prevented or at least attenuated the increases in heart rate (30%), mean arterial pressure (37%), mean pulmonary artery pressure (165%), left ventricular filling pressure (230%), total peripheral resistance (50%), pulmonary vascular resistance (100%) and in the rate-pressure product (66%) which were associated with the use of ketamine as the sole anaesthetic agent. In addition, the flunitrazepam-pretreatment abolished the fall in cardiac index and stroke index which occured in patients given ketamine alone. Flunitrazepam therefore appears to be a promising drug to prevent adverse cardiovascular reactions, when ketamine should be chosen for induction of anaesthesia. Neuroleptanalgesia and muscle relaxation also proved effective in controlling the sympathomimetic actions of ketamine. The response of the mean pulmonary artery pressure and of the ventricular filling pressures to ketamine in this group was even more damped than in the patients pretreated with flunitrazepam alone.
0.928737
Self-motion magnitude estimation during linear oscillation: changes with head orientation and following fatigue.
Two types of experiments concerning estimated magnitude of self-motion during exposure to linear oscillation on a parallel swing are described in this paper. Experiment I examined changes in magnitude estimation as a function of variation of the subject's head orientation, and Experiments II a, II b, and II c assessed changes in magnitude estimation performance following exposure to sustained, "intense" linear oscillation (fatigue-inducing stimulation). The subjects' performance was summarized employing Stevens' power law (R = k . Sn, where R is perceived self-motion magnitude, k is a constant, S is amplitude of linear oscillation, and n is an exponent). The results of Experiment I indicated that the exponents, n, for the magnitude estimation functions varied with head orientation and were greatest when the head was oriented 135 degrees off the vertical. In Experiments II a-c, the magnitude estimation function exponents were increased following fatigue. Both types of experiments suggest ways in which the vestibular system's contribution to a spatial orientation perceptual system may vary. This variability may be a contributing factor to the development of pilot/astronaut disorientation and may also be implicated in the occurrence of motion sickness.
0.897762
Reactivities of neutral and cationic forms of 2,2'-dipyridyl disulphide towards thiolate anions. Detection of differences between the active centres of actinidin, papain and ficin by a three-protonic-state reactivity probe.
The second-order rate constants (k) for the reactions of 2,2'-dipyridyl disulphide (pKa2,45) with 2-mercaptoethanol (pKa9.6) and with benzimidazol-2-ylmethanethiol (pKa values 5.6 and 8.3) were determined at 25 degrees C at I 0.1 by stopped-flow spectral analysis over a wide range of pH. These were used to calculate the pH-independent second-order rate constants (k) for the reactions of neutral 2,2'-dipyridyl disulphide and of its monocation with the 2-mercaptoethanol thiolate anion (associated pKa9.6) and with the benzimidazol-2-ylmethanethiol zwitterion (associated pKa5.6). For both thiolate ions, the rate-enhancement factor (kmonocation/kneutral disulphide) is about 1.5x10(3). The dependence on pH in acidic media of k for the reaction of 2,2'-dipyridyl disulphide with actinidin, the thiol proteinase from Actinidia chinensis, was shown to differ from the forms of pH-dependence observed for the analogous reactions with papain (EC 3.4.22.2) and ficin (3.4.22.3). The reactivity of the 2,2'-dipyridyl disulphide dication and its apparent sensitivity to the presence and location of a positive charge in the attacking thiol are discussed.
0.889701
Prevention by pyrazole of the effects of chronic ethanol administration on the redox states of the hepatic nicotinamide--adenine dinucleotide (phosphate) couples and on liver and brain tryptophan metabolism in the rat.
Chronic administration of pyrazole in the diet of rats does not cause toxicity and prevents the chronic effects of ethanol on: (1) the redox states of the hepatic NAD(P) couples; (2) liver tryptophan pyrrolase activity; (3) brain tryptophan and 5-hydroxytryptamine metabolism.
0.943912
The stimulus--secretion coupling 4-methyl-2-oxopentanoate-induced insulin release.
1. Pancreatic islet insulin secretion and 45Ca uptake showed similar responses to variation in the extracellular concentration of 4-methyl-2-oxopentanoate with a threshold at 4 mM and a maximal response at a 25 mM concentration. 2. Islet respiration, acetoacetate production and rates of substrate utilization, oxidation and amination all changed as a simple hyperbolic function of 4-methyl-2-oxopentanoate concentration and exhibited a maximal response at 25 mM. 3. The responses of ATP content, [ATP]/[ADP] ratio, adenylate energy charge and [NADH]/[NAD+] ratio were also hyperbolic in nature but were maximally elevated at lower concentrations of the secretagogue. The islet [NADPH]/[NADP+] ratio, however, was tightly correlated with parameters of metabolic flux, 45Ca uptake and insulin release. 4. NH4+ and menadione, agents that promote a more oxidized state in islet NADP, did not affect islet ATP content or the rates of [U-14C]4-methyl-2-oxopentanoate oxidation or amination, but markedly inhibited islet 45Ca uptake and insulin release. 5. It is proposed that changes in the redox state of NADP and Ca transport may serve as mediators in the stimulus-secretion coupling mechanism of insulin release induced by 4-methyl-2-oxopentanoate.
0.86011
Drug-induced changes in the formation, storage and metabolism of tyramine in the mouse.
1 The endogenous concentrations of p- and m-tyramine in the mouse striatum were determined by a mass spectrometric integrated ion current technique and concentrations were 21.3 and 6.1 ng/g, respectively.2 The present results further confirm that the administration of antipsychotic drugs (chlorpromazine, haloperidol, spiroperidol, alpha-flupenthixol and (+)-butaclamol) reduces p-tyramine concentrations in the mouse striatum. In contrast, striatal m-tyramine showed a tendency to increase, although only in the cases of haloperidol and (+)-butaclamol were the differences statistically significant.3 Administration of antipsychotic drugs to mice pretreated with tranylcypromine or clorgyline produced a significant reduction in striatal p-tyramine when compared with the concentrations obtained in mice given a monoamine oxidase inhibitor. These results suggest that antipsychotic drugs reduce striatal p-tyramine formation. The moderate increases produced by monoamine oxidase inhibitors on striatal m-tyramine were not significantly changed after the administration of an antipsychotic.4 Drugs that reduce dopamine turnover (apomorphine, piribedil, lergotrile, alpha-methyl-p-tyrosine) significantly increased the concentration of striatal p-tyramine. No significant changes were observed in striatal m-tyramine concentrations after apomorphine, piribedil or lergotrile; alpha-methyl-p-tyrosine produced a reduction in its concentration.5 Drugs that impair amine storage (reserpine, tetrabenazine, oxypertine) reduced striatal concentrations of p-tyramine. The m-tyramine concentrations were also reduced by reserpine or tetrabenazine.6 It is possible that striatal tyramines act as modulators, or transmitters, and control the activity of dopaminergic neurones.
0.819607
A renal function study in 30 patients on long-term lithium therapy.
30 patients on long-term lithium therapy have been studied. The results are presented of the urinary concentrating ability after water deprivation and the intranasal administration of vasopressin, of the simultaneous determination of glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), of the minimal urine pH after an oral dose of ammonium chloride, and of the urinary beta-2-microglobulin excretion. Mean urine concentration (+/- SEM) after 22 hr water deprivation (= Uosm) amounted to 854 +/- 22 mOsm/kg H2O, mean GFR was 101 +/- 4 ml/min, mean ERPF 360 +/- 18 ml/min, and mean minimal urine pH 4.95 +/- 0.06. In 8 out of 30 patients there was polyuria. In these 8 patients the values were 778 +/- 51 mOsm/kg H2O, 113 +/- 6 ml/min, 415 +/- 33 ml/min and 4.99 +/- 0.08, respectively. Serum levels of beta-2-microglobulin and lysozyme and the urinary excretion of beta-2-microglobulin were normal in all patients. No correlation was established between Uosm and the serum lithium concentration during the test (0.8 +/- 0.05 mmoles/l) nor between Uosm and the average serum lithium level during treatment (0.79 +/- 0.03). GFR was only correlated with age. It was found that administration of indomethacin during the concentration test increased Uosm in these patients. The results suggest that, given proper dosage and surveillance, long-term treatment with lithium is not likely to cause disturbances in renal function.
0.875082
The pharmacokinetic profile of ochratoxin A in the rat after oral and intravenous administration.
A single oral or iv dose (2.5 mg/kg) of ochratoxin A was administered to healthy adult rats. A spectrofluorimetric method was used to determine the toxin level in plasma. The results suggest that the toxin is distributed in two kinetically distinct body compartments. By use of computer techniques, values were assigned to the pharmacokinetic parameters for ochratoxin A in the rat. The half-life of the drug was around 55 hr for either oral or iv administration. Digital computer-simulated curves of the toxin levels in the central and peripheral compartments as well as a total elimination curve were generated. When 14C-ochratoxin A was administered to rats, there were peaks of radioactivity 1 and 6 hr after injection. Ochratoxin alpha was the only metabolite recovered from the cecum and large intestine. Ochratoxin A was excreted via urine and feces, both as the free drug and hydroylzed to ochratoxin alpha; in urine there were five unidentified labeled metabolites. Some of the water-soluble radioactivity was not recovered in the acidic ether extract of the excreta. A hierarchical clustering technique was used to classify the organs in central and peripheral compartments. Muscle, fat, and skin were found to belong to the deep compartment. The residue problem is discussed.
0.901957
Intrinsic sympathomimetic activity of penbutolol.
Six healthy volunteers took part in a randomized, single-blind, crossover study to quantitate the intrinsic sympathomimetic activity (ISA) of penbutolol in comparison with one drug possessing ISA (alprenolol) and with the standard non-ISA drug (propranolol). Single intravenous and one week oral administrations were studied. Complete parasympathetic and sympathetic isolation of the heart was obtained by administration of atropine 0.04 mg/kg body weight i.v. and propranolol 0.4 mg/kg i.v., or corresponding equipotent doses of alprenolol 0.4 mg/kg i.v. and penbutolol i.v. 0.08 mg/kg. In the chronic, oral study propranolol 160 mg b.i.d. was given, or corresponding equipotent doses of alprenolol (400 mg b.i.d.) or penbutolol (40 mg b.i.d.). The test procedure included measurement of heart rate and blood pressure in the supine, sitting and standing positions, and during isometric and dynamic exercise. ISA was calculated by comparison of the change in of heart rate with that produced by propranolol. The ISA of alprenolol was 22--26% and of penbutolol 12--18% of maximal sympathetic activity. Isometric and dynamic exercise gave comparable ISA values.
0.881563
Correlation of cholesterol and bilirubin solubilization in bile salt solution.
Not only cholesterol but also bilirubin were considered to be solubilized by bile salt micelles. The correlation of cholesterol and bilirubin solubilization in aqueous conjugated and unconjugated bile salts solution and the effect of calcium on their solubilization were studied in this report. Cholesterol solubilization was usually reduced to some extent with increasing amount of added bilirubin. Bilirubin solubilization was always reduced by the co-existence of solubilized cholesterol. It was found that the addition of calcium increased cholesterol solubilization in conjugated bile salts system. On the other hand, calcium reduced bilirubin solubilization due to the formation of insoluble calcium bilirubinate especially in a high pH range of unconjugated bile salts system. Cholesterol solubilization in conjugated bile salts system was relatively lower than unconjugated bile salts system with or without added calcium, however co-existing bilirubin minimized these differences. The pH-dependency of cholesterol and bilirubin solubilization was small in conjugated bile salts system. On the contrary, it was remarkably bigger in unconjugated bile salts-calcium system.
0.927402
Mannose-sensitive stimulation of human leukocyte chemiluminescence by Escherichia coli.
Escherichia coli organisms with mannose-sensitive adherence factors (adhesins) are known to associate with human peripheral leukocytes (WBCs) in vitro in the absence of serum. To determine whether the WBC respiratory burst is activated during the interaction with E. coli, WBC chemiluminescence was measured. E. coli with mannose-sensitive adhesins stimulated a sharp burst of chemiluminescence which peaked 15 to 30 min after the bacteria and WBCs were mixed. Stimulation of chemiluminescence could be abrogated by including 10 mM alpha-methyl-D-mannoside in the test suspension. The addition of alpha-methyl-D-mannoside up to 20 min after the E. coli and WBCs were combined caused a rapid decrease in chemiluminescence. E. coli stimulation of chemiluminescence could not be inhibited by pretreating the WBCs with purified type 1 pili (fimbriae). E. coli lacking mannose-sensitive adhesins failed to stimulate chemiluminescence. The results emphasize the importance of mannose-sensitive adhesins in the association of E. coli with WBCs and suggest that the E. coli-WBC interaction system may be a useful tool for studying the mechanisms involved in the activation of the respiratory burst during phagocytosis.
0.89995
Comparative immunogenicity of group 6 pneumococcal type 6A(6) and type 6B(26) capsular polysaccharides.
The comparative immunogenicity of the two cross-reacting group 6 pneumococcal capsular polysaccharides, type 6A(6) and type 6B(26), was studied with hyperimmune rabbit typing antisera and with sera from adult volunteers injected with polyvalent pneumococcal vaccines containing either 50 mug of type 6A (U.S. designation, type 6) or 50 mug each of type 6A and type 6B (U.S. designation, type 26) polysaccharides. Both group 6 polysaccharides were linear copolymers composed of 1 mol each of d-galactose, d-glucose, l-rhamnose, and d-ribitol phosphate. They differed only in that type 6A had a rhammopyranosyl-(1 --> 3)-d-ribitol bond and the type 6B had a rhamnopyranosyl-(1 --> 4)-d-ribitol bond. Quantitative precipitation and absorption analyses with rabbit hyperimmune antisera induced by simultaneous injection with type 6A and type 6B organisms revealed extensive cross-reactions between the two group 6 polysaccharides. There was less, although still quite extensive, cross-reactivity between the two group 6 polysaccharides examined with antisera from rabbits injected with only one of the group 6 pneumococci. In a radioimmunoassay, using (14)C internally labeled type 6A or type 6B polysaccharide antigens, there was no difference in the serum antibody level to either type of volunteer injected with polyvalent pneumococcal vaccines containing type 6A or both type 6A and type 6B polysaccharides. These studies indicate that the structural similarity of the pneumococcal group 6 polysaccharides confers extensive cross-reactivity with hyperimmune typing antisera prepared with whole organisms or after injection of purified polysaccharides in adult volunteers. With our current polysaccharides, it appears that a polyvalent pneumococcal vaccine formulation that contains only type 6A will serve to induce the maximum amount of serum antibodies to both group 6 organisms.
0.940303
A cohort study of canine testicular neoplasia.
A prospective epidemiologic study of canine testicular neoplasia was undertaken in the Philadelphia area in 1971, with the cooperation of private veterinary practitioners. By the end of 1975, 938 dogs had been monitored for an average of 2 years. The cohort consisted of 609 cryptorchid and 329 age- and breed-matched controls. The incidence of testicular neoplasia in the cryptorchid subcohort was 12.7/1,000 dog-years at risk. Testicular neoplasms did not develop in controls. A large proportion of the dogs were below the average age at onset for this neoplasm. Among dogs over 6 years of age, the incidence was 68.1/1,000 dog-years at risk. The incidence of Sertoli cell tumors and seminoma was approximately twice as high in dogs with unilaterally retained inguinal testicles as in abdominal cryptorchids. Sertoli cell tumors developed in 10 dogs and seminoma developed in 6. One half of the testicular neoplasms that developed did so within the first year of observation. This study demonstrated the feasibility of conducting prospective epidemiologic studies of canine diseases with the assistance of practicing veterinarians.
0.915937
Effects of blood on blood culture medium.
The morphological and biochemical changes that occur after inoculation of sterile blood into a blood culture medium (tryptic soy broth) with sodium polyanetholesulfonate and CO(2) were investigated. Cellular changes, pH, PCO(2), and PO(2) were monitored and evaluated. Erythrocytes became crenated and developed precipitated hemoglobin inclusions within 4 h. The lymphocytes appeared morphologically intact at 24 h, and by 48 h a few cells had undergone transformation. Many neutrophils were vacuolated at 24 h. Neutrophils capable of phagocytizing Staphylococcus aureus were observed after 18 h of incubation. Identifiable eosinophiles were present on day 6 of the study. A decrease in PO(2) in the unvented bottles from 44.4 to 8 mm of Hg occurred by 24 h. PO(2) remained low for 6 days, after which a slight increase occurred. An increase in PO(2) in the vented bottle from 51 to 58 mm of Hg occurred by 24 h of incubation. In both the vented and unvented bottles the PCO(2) increased. This increase was markedly more rapid in the unvented bottle. From a pH of 7.06 a decrease occurred for the first 24 h after inoculation, with the pH stabilizing at 6.8 in the vented bottles and at 6.6 in the unvented bottles. The biochemical changes that occurred in the vented culture bottles stabilized more rapidly than those of the unvented bottles. Changes caused by the addition of sterile blood to a blood culture medium resulted in conditions which departed considerably from accepted optima for the isolation of clinically important microorganisms. The phagocytosis of organisms that occurred may also have reduced the yield.
0.809353
Direct and reflex effects of nitroglycerin on the blood volume distribution, evaluated by regional weighing in the cat.
The effects of nitroglycerin on the blood volume distribution were studied with a method of regional weighing in the anaesthetized cat. An i.v. bolus injection of nitroglycerin produced a dose-dependent decrease in arterial pressure accompanying a decrease in the thoracic blood volume. The latter change was associated with blood volume increases principally in the abdomen, and slightly in the hindquarters. Elimination of the cardiovascular reflex effects by carotid sinus denervation and cervical vagotomy signficantly enhanced and prolonged the following changes: the hypotension, the decrease in thoracic blood volume and the volume pooling in the abdomen. The magnitude of increase in hindquarters blood volume was not significantly affected by the denervation procedures, but the duration was much prolonged. The results indicate that the major site of nitroglycerin-induced venous pooling is in the splanchnic circulation. The peripheral venous pooling is produced at the expense of a decrease in the central or pulmonary blood volume. The secondary reflex adjustments tend to minimize the direct effects of nitroglycerin on the blood pressure and blood volume distribution.
0.921659
The neuromuscular and autonomic blocking activities of pancuronium, Org NC 45, and other pancuronium analogues, in the cat.
Twenty-six mono- or bis-quaternary salts of 3,17-dioxy-2 beta, 16 beta-dipiperidino-5 alpha-androstanes (including pancuronium) and one 17-desoxy congener were tested for neuromuscular blocking and autonomic blocking activities in the chloralose-anaesthetized cat. The 17 beta-acetoxy series, all the members of which contain an acetylcholine-like fragment in the steroidal D-ring, was most selective for effecting neuromuscular blockade. The salient member of this series is 3 alpha, 17 beta-diacetoxy-2 beta, 16 beta-dipiperidino-5 alpha-androstane 16 beta-N-monomethobromide (Org NC 45) which is highly selective in blocking neuromuscular transmission in that a dose approximately sixty times greater than the neuromuscular blocking dose was required to block responses to vagal stimulation. In contrast, in doses sufficient to produce neuromuscular block, pancuronium simultaneously blocked responses to vagal stimulation. Moreover, pancuronium and Org NC 45 exhibited the same order of neuromuscular blocking activity and therefore the latter potentially represents a useful addition to the armamentarium of neuromuscular blocking agents currently in clinical use.
0.903153
[Development in the treatment of congenital dislocation of hip (author's transl)].
Authors review the development in the treatment of congenital dislocation and dysplasy of hip and demonstrate the results with various methods. Results with treatment according to Lorenz (1040 cases) were unsatisfactory because of frequent occurance (66.3 percent) of osteochondritis. The treatment with Frejka cushion (360 cases) did not improve basically the results. Pavlik's strapping, especially when started under 1 month of age gave excellent results (3156 cases). In operative treated the results of 332 Colonna operations were unsatisfactory because of consecutive deformation of the hip and restriction of movements. Open reduction with varisation derotation osteotomy (474 cases) provided good acetabular development especially in cases where articular cartilage and upper limbus could be saved. Salter's operation is successful when proper indications are considered, but should be performed only after 1--2 years of observation of the acetabular development in non improving cases. The Chiari procedure can improve the weight bearing surfaces in cases of steep acetabular roof flat acetabulum and consecutive subluxation. In 557 cases of varisation derotation osteotomy subcapital coxa valga occured frequently. Basic principle of treatment remains prevention, early recognition and treatment after birth.
0.857777
Superhelical DNA in Streptococcus sanguis: role in recombination in vivo.
Competent Streptococcus sanguis treated with non-lethal doses of coumermycin A1 immediately before or after uptake of radioactive transforming DNA were reduced in their capacity to yield transformants. This treatment did not alter bacterial ability to bind DNA in DNase I-resistant form, nor did it prevent the single-stranded donor DNA-recipient protein complexes formed upon uptake at the surface of the bacteria from translocating to chromosomal sites. Inhibition of transformation by heterospecific DNA was greater than that by homospecific DNA. The reduction in transformant yield was not accompanied by any loss of donor counts incorporated into the recipient chromosome, but rather by a loss of genetic activity of incorporated donor material indicating a failure of genetic integration and degradation of donor DNA as a consequence of coumermycin treatment. The inhibitory effect of coumermycin on transformation was associated with in vivo loss of chromosomal DNA superhelicity, The chromosomal DNA remained intact, however, indicative of inhibition of a gyrase-like enzyme responsible for the maintenance of negative supercoiling of the S. sanguis chromosome. Upon treatment with the drug, a coumermycin-resistant mutant strain showed neither loss of chromosomal superhelicity nor any inhibitory effect on genetic integration of donor DNA. The evidence supports the idea that chromosomal superhelicity promotes genetic recombination in vivo.
0.824634
[Beta-blocking agents alone or combined with diuretics or alpha-adrenolytics in the treatment of essential arterial hypertension].
The Authors examine the antihypertensive effectiveness of the beta-adrenergic receptor blocking agents, according to their personal experience and a review of the bibliography. It is not cleared yet how these drugs reach their hypotensive effect. It is reasonable to assume however that several factors are involved: cardiac output, intravascular volume changes, plasma renin activity and peripheral resistance. Thirty patients suffering from essential hypertension not complicated by cardiac or renale failure were treated. Patients were allocated at random into one of three subsets of ten. In group A oxprenolol was given for 8 weeks and the dose was gradually increased up to 300 mgs daily. Oxprenolol was administered in combination with clortalidone in group B and with phentolamine in group C. A clinically satisfactory reduction in blood pressure was attained in no subset, despite the significant decrease of mean blood pressure. The blockade of beta-adrenergic receptors alone has proved to be less effective than the combined administration of oxprenolol and clortalidone or of oxprenolol and phentolamine. No differences were observed between the two combinations.
0.833108
Geochemical surveys in the United States in relation to health.
Geochemical surveys in relation to health may be classified as having one, two or three dimensions. One-dimensional surveys examine relations between concentrations of elements such as Pb in soils and other media and burdens of the same elements in humans, at a given time. The spatial distributions of element concentrations are not investigated. The primary objective of two-dimensional surveys is to map the distributions of element concentrations, commonly according to stratified random sampling designs based on either conceptual landscape units or artificial sampling strata, but systematic sampling intervals have also been used. Political units have defined sample areas that coincide with the units used to accumulate epidemiological data. Element concentrations affected by point sources have also been mapped. Background values, location of natural or technological anomalies and the geographic scale of variation for several elements often are determined. Three-dimensional surveys result when two-dimensional surveys are repeated to detect environmental changes.
0.811939
Geochemistry and ecology.
This paper discusses the importance of geochemistry as a determining factor in the evolutionary development of plant assemblages. Three contrasting examples of geochemical systems are described and considered in relation to their effects on plant growth and development. Soils derived from serpentines may contain elevated and sometimes toxic concentrations of Cr and Ni depending on mineral composition and weathering processes. These conditions have so modified plant growth during the past few million years that specialized floras have evolved on particular sites. Extensive areas throughout the world contain high concentrations of Se but these have not always been accompanied by the development of specific floras. Geochemistry can help explain how Se-specific floras have developed in several Western States of America but are absent on Se-rich sites in the Republic of Ireland. Pronounced effects of As toxicity in plants have been recognized in recent years especially from areas polluted by smelter waste and fallout. As-tolerant genotypes have developed during the past 100 years and may still be evolving at the present time.
0.817777
Trace metals in waters.
The topic of this paper is extremely broad, and to allow more useful discussion, emphasis is placed on trace (less than 1 mg/l) metals in fresh surface waters and in drinking waters. An attempt is made to give a broad overview of current knowledge, problems and research with particular reference to the following: (1) metals of interest, current standards of water quality relevant to health, and concentrations of metals in waters; (2) sources of, and other factors affecting, the concentrations of metals; (3) general problems in the measurement of metal concentrations; (4) important research topics.
0.879421
Trace elements in man.
It is likely that most, if not all, of the elements found to be essential in animals will be shown to be so for man, and the clinical picture produced by deficiency of the elements in the human patient will differ little from that seen in the animal, although this has been established for only five elements (I, Fe, Cu, Co and Zn). However, the link between lack of a given element in the soil and a human patient is far less direct and much more complex than that met with in the animal grazing on deficient pastures, except in isolated primitive communitis. Zn is the most protean of the trace elements and has been chosen to illustrate this in human practice. Excesses of essential elements (both trace and major) give rise to toxic effects and the importance of a proper balance especially of the transitional elements in the human diet is discussed with special reference to Cu, Zn and Fe. Certain non-essential trace elements are individual and community hazards: Cd, Pb and Hg are the principal offenders for humans. Mankind is now largely dependent on grassland products, cereals and livestock with increasing dominance of the former in human nutrition. This has reduced the bioavailability of trace elements so that study of trace metals, especially Zn and Cu, in skeletal and dental remains at human burial and occupation sites should prove useful in assessing the consequences of this striking change in dietary habits.
0.838251
Normal prolactin responses in tardive dyskinesia.
Tardive dyskinesia has been hypothesized to be caused by a neuroleptic-induced dopamine hypersensitivity in the nigrostriatal system. This study evaluated with dopamine antagonists the possibility that such dopamine hypersensitivity extends to the tuberoinfundibular dopamine (TIDA) system, which regulates, by inhibition, pituitary prolactin secretion. Plasma prolactin concentrations in six patients with tardive dyskinesia were assessed in four conditions: During chronic haloperidol therapy; serially after abrupt haloperidol withdrawal; while unmediated; and in response to an acute dose of 0.5 mg IM haloperidol. In all four conditions, prolactin responses did not differ from those observed in normal subjects and schizophrenic patients without tardive dyskinesia. It is concluded that there is no evidence for post-synaptic dopamine hypersensitivity in the TIDA-pituitary pathway in patients with tardive dyskinesia, consistent with other reports assessing hormonal responses to dopamine agonists in such cases. It is further suggested that neuroleptic-induced dopamine hypersensitivity does not occur in the TIDA-pituitary system in humans, since it was not manifest in these tardive dyskinesia patients who would be thought particularly prone to develop it.
0.892131
[Radiation decomposition of humic substances in landfill disposal leachate. TOC reduction and CO2 formation (author's transl)].
The leachate generated from landfill contains humic substances such as humic acid and fluvic acid. It shows, in general, high chemical oxygen demand (COD) and biological oxygen demand (BOD), and colors in dark brown. When the leachate collected on the No. 15 landfill in Tokyo Bay was irradiated by gamma-rays from a 60Co source in bubbling air, the total organic carbon (TOC) decreased with increasing dose and the brown color was bleached. The effects of pH, flow rate, and dose rate on the decrease of TOC, the variations of UV spectrum, and the formation of carbon dioxide by the irradiation were examined. The decreasing rate of TOC increased with an increase of the flow rate up to approximately 1l/min and showed a maximum value in the region of pH 4 approximately 6. It was also dependent on the dose rate and increased with a decrease of the dose rate. The radiation chemical yield, G(--TOC), reached 162 at low dose rate of 1.3 X10(4) rad/h. This result suggests that a radiation-induced chain reaction occurred. The amount of TOC decreased was almost equal to that of carbon dioxide formed. This result shows that the organic substances were decomposed by irradiation to carbon dioxide as a final product and it was ejected from the solution.
0.909924
[Value of the meiosis test in male infertility].
The histological evaluation of testicular biopsy in the investigation of infertility was supplemented by cytogenetic analysis of spermatogenesis in 72 patients from 1976--1978. The results show meiosis analysis to be a practical aid in the assessment of male infertility. It enables the point of interruption in the meiotic process to be accurately identified. A review of relative populations of meiotic and of interphase nuclei (the meiotic index) permits evaluation of a quantitative disturbance of spermatogenesis, a finding that is of particular value when establishing a patient's prognosis. Moreover, meiotic analysis makes it possible to recognize cytogenetic anomalies which could be responsible for the infertility state and which were chiefly seen in patients whose so-called primary infertility was hitherto classified as being of unknown origin. In two patients we thus identified a small additional chromosome in a fraction of the germinal cells, and also an abnormal pairing of all chromosomes, or the sex chromosomes alone, during the first meiotic division.
0.86137
Influence of stroma-free hemoglobin solution on renal function in dogs.
In the presented series of experiments, stroma-free hemoglobin solution (SFHS) was used as a perfusate for extracorporeal perfusion of kidneys and for exchange transfusion. It was shown that SFHS was adequatly oxygenated both as perfusate during the extracorporal perfusion and in the lungs after the blood exchange. Furthermore, there was provided evidence that oxygen was being transported and released in the tissues. Histologic examination of the kidneys demonstrated hemoglobin casts in the glomerules. Most of them were seen after extracorporal perfusion of isolated kidneys, less frequently after perfusion in situ and few casts were present after exchange transfusion. The cause of these depositions may be small remnants of stroma in the preparation. Furthermore it is possible, that at the beginning of the extracorporal perfusion of the kidneys the urine pH was below 6 and then a hemoglobin casts formation could occur. There were essential no changes in urine pH in the course of blood exchange. In this group were only few casts present in the kidneys.
0.850898
Abnormal erythrocyte metabolism in hepatic disease: effect of NADP repletion.
Erythrocytes from ten patients with severe liver disease displayed low methylene blue-stimulated hexose monophosphate (HMP) shunt activity and glucose recycling despite elevated total glucose consumption when compared to controls. Heinz body formation was increased and reduced glutathione concentration significantly decreased. After hemolysis, no differences in methylene-blue estimulated HMP shunt activity or glucose recycling could be demonstrated between patients and controls. The addition of 2- and 4-mM NADP to the hemolysates produced significantly greater HMP shunt activity and glucose recycling in the patients' hemolysates. The addition of NADPH to the incubation mixture produced no significant stimulation of either HMP shunt activity or glucose recycling, unless methylene blue was also added. Omission of NAD or phosphate from the incubation mixture produced no change in shunt metabolism. The absence of supplemental ATP resulted in extremely low shunt metabolism and refractoriness to NADP stimulation in both patients and controls. In the absence of additional magnesium, a reduction of shunt metabolism was noted. These data suggest that the defect in stimulated shunt metabolism in the intact erythrocytes of patients with hepatic disease does not result from an absolute enzyme deficiency, but rather from an unavailability of NADP or other cofactor.
0.847432
Viral aggregation: buffer effects in the aggregation of poliovirus and reovirus at low and high pH.
The effects of the buffer employed in maintaining a given pH value were tested on the aggregation of two viruses, poliovirus and reovirus. Poliovirus was found to aggregate at pH values of 6 and below, but not at pH 7 or above, except in borate buffer. Reovirus aggregated at pH 4 and below, but was found to aggregate only in acetate or tris(hydroxymethyl)aminomethane-citrate buffers at pH 5. Other buffers tested for aggregation of reovirus at pH 5 (succinate, citrate, and phosphate-citrate) induced little aggregation. No significant aggregation was found for reovirus at pH 6 and above. For both viruses, the most effective aggregation was induced by buffers having a substantial monovalently charged anionic component, such as acetate at pH 5 and 6 or citrate at pH 3. Cationic buffers at low pH, such as glycine, were generally weaker in aggregating ability than anionic buffers at the same pH. These results, when correlated with the isoelectric point of the viruses (poliovirus at pH 8.2; reovirus at pH 3.9) indicated that both viruses aggregated strongly when their overall charge was positive, but only under certain circumstances when their overall charge was negative. Although reovirus aggregated massively at its isoelectric point, poliovirus remained dispersed at its isoelectric point. The conclusion can be drawn that those pH and buffer conditions which induced aggregation of one virus do not necessarily induce it in another.
0.940275
The sodium channel in non-impulsive cells. Interaction with specific neurotoxins.
The cell line C9 used in this paper has a resting potential of --50 mV (+/- 10 mV) but is unable to generate an action potential upon electrical stimulation. The cell membrane has receptors for the selectivity filter toxin tetrodotoxin as well as for the gating system toxins, veratridine, scorpion toxin and sea anemone toxin. The Na+ channel which remains silent to electrical stimulation in the absence of toxins can be chemically activated by the gating system toxins. This has been demonstarted by electrophysiological techniques and by 22Na+ flux studies. The electrophysiological approach has shown that the sea anemone toxin is able to induce a spontaneous slow-wave activity inhibited by tetrodotoxin. 22Na+ influx analyses have shown that veratridine and the sea anemone toxin produce an important increase of the initial rate of 22Na+ influx into the C9 cell. The stimulation of 22Na+ entry by these gating system toxins is similar to that found using spiking neuroblastoma cells. Veratridine and the sea anemone toxin on one hand as well as veratridine and the scorpion toxin on the other hand are synergistic in their action to stabilize an open and highly permeable form of the sodium channel. Stimulation of 22Na+ entry into the cell through the sodium channel maintained open by the gating system neurotoxins is completely suppressed by tetrodotoxin.
0.835805
The function of fimbriae in Myxococcus xanthus. II. The role of fimbriae in cell-cell interactions.
Anti-fimbriae antiserum specifically inhibited swarming but no gliding motility per se in Myxococcus xanthus. However, formation of motile aggregates on agar and clumps in liquid media correlated with the presence of fimbriae. Ethylenediaminetetraacetic acid which inhibited swarming also inhibited fimbriae formation. Direct electron-microscopic observations revealed that fimbriae establish contact with apposing cell surfaces. Intact but not depolymerized fimbriae exhibited hemagglutination activity against guinea pig erythrocytes. This activity was inhibited by mannose, N-acetyl-D-galactosamine, and to a lesser degree by fructose, raffinose, melibiose, and alpha-methyl-D-mannoside. It is concluded that fimbriae are organelles which function to establish and maintain intercellular contacts, perhaps by a lectin-like function, during the coordinated movement of cell aggregates' (swarming) in myxobacteria. This hypothesis is supported by the observations of other workers that genes determining movement of cells in groups also control fimbriation in M. xanthus.
0.85398
Allogeneic bone marrow transplantation for severe aplastic anaemia--the London experience.
Using the Seattle protocol with minor modifications, 23 patients with severe aplastic anaemia received allogeneic bone marrow transplants from HLA/mixed leucocyte culture matched sibs in three London centres between 1973 and 1977. Ten patients (43.5%) are alive 6 months to 5 years after transplantation, and are well with full haemopoietic reconstitution, two with autologous bone marrow recovery following the graft procedure. A failure of the marrow graft to take, or take followed by rejection occurred in 12 patients (52%). Failure of marrow recovery was associated with a high early mortality from bacterial or fungal infection. The only survivors amongst those who rejected the first graft were four patients in whom a subsequent graft from the same donor was successful, and two in whom autologous recovery occurred. Graft versus host disease (GVHD) occurred in seven patients, and was fatal in one case. The most frequent complication after successful engraftment was varicella-zoster infection which occurred in five patients and was fatal in one patient. The overall results compare favourably with those from other transplant centres, but the high rate of graft rejection and low incidence of GVHD differ from other series. The results should encourage further referral of patients with severe AA for bone marrow transplantation.
0.876891
[The antiallergic effect of Balkis. A rhino-manometric study].
The antiallergic and decongestive effects of the common cold preparation Balkis was tested by rhinomanometry in human volunteers usually suffering from allergic rhinitis after oral treatment. The nasal irritation in these patients was induced by administration of the specific allergen. This kind of test is especially appropriate for the control of drugs in cases of ordinary colds, as the test conditions are reproducible in symptomatically similar cases. The rhinomanometrical control of the respiratory resistance was carried out before and after an allergenic exposal as well as before and after administration of Balkis and allergenic exposal in 30 patients (17 females, 13 males; 9-49 years old). It is shown that Balkis had a good to satisfactory antiallergic effect in 67% of all cases. In 33% of the cases the antiallergic effect was not evident. This result confirms objectively the good antiallergic effect of this common cold preparation by oral administration. Balkis was well tolerated in all of the 30 patients. The symptoms of slight fatigue which appeared in 1/3 of all cases were only transitory.
0.902417
Enzyme histochemical characteristics of human and kitten odontoclasts and kitten osteoclasts: a comparative study using whole cells.
Methods for the histochemical demonstration of enzymes in whole cell preparations of odontoclasts and osteoclasts are described. Enzyme histochemical characteristics of human and kitten odontoclasts from resorbing primary teeth and of osteoclasts from kitten femur metaphyses were determined and compared. The enzyme profiles, times for the appearance of detectable reaction product, intensity of the reactions and localization of the reaction products were similar in all three types of giant cell. These findings suggest that odontoclasts have enzyme properties and metabolic functions similar to those of osteoclasts. Species differences appear to be minor, although the NADP-dependent enzymes are less active in human than in kitten odontoclasts. Both odontoclasts and osteoclasts are rich in enzymes concerned with energy production and possess considerable activity of enzymes usually associated with catabolic functions. Metabolic pathways are well developed in respect of the utilization of succinic, malic, glutamic, lactic and isocitric acids, beta-hydroxybutyric acid and glucose-6-phosphate, and they also possess phosphatases, non-specific esterases and leucine naphthylamidase. The distribution of enzyme reaction products for the individual enzymes demonstrated is consistent with the presence in these cells of large numbers of mitochondria and lysosome-like organelles. Considerable phosphatase activity is demonstrable in both odontoclasts and osteoclasts at both neutral and acid pH.
0.930118
Complexes of technetium with pyrophosphate, etidronate, and medronate.
The reduction of [99Tc]pertechnetate was studied as a function of pH in complexing media of pyrophosphate, methylene diphosphonate (MDP), and ethane-1, hydroxy-1, and 1-diphosphonate (HEDP). Tast (sampled d-c) and normal-pulse polarography were used to study the reduction of pertechnetate, and normal-pulse polarography (sweeping in the anodic direction) to study the reoxidation of the products. Below pH 6 TcO4-was reduced to Tc(III), which could be reoxidized to Tc(IV). Above pH 10, TcO4-was reduced in two steps to Tc(V) and Tc(IV), each of which could be reoxidized to TcO4-. Between pH 6 and 10 the results differed according to the ligand present. In pyrophosphate and MDP, TcO4- was reduced in two steps to Tc(IV) and Tc(III); Tc(III) could be reoxidized in two steps to Tc(IV) and TcO4-. In HEDP, on the other hand, TcO4- was reduced in two steps to Tc(V) and Tc(III), and could be reoxidized to Tc(IV) and TcO4-. Additional waves were observed; they apparently led to unstable products.
0.819431
Growth and differentiation of Trypanosoma cruzi cultivated with a Triatoma infestans embryo cell line.
Trypanosoma cruzi strain Peru was cultivated in the presence of an established cell line of Triatoma infestans embryo cells (TI- 32). Bloodstream trypomastigotes differentiated into amastigote-like cells (first differentiation phase) which multiplied to form large clusters of cells. Because of their clustering nature, a new term, "staphylomastigotes," has been proposed for this stage. After 10 days of cultivation, 90% of the staphylomastigotes underwent differentiation (2nd differentiation phase) to trypomastigotes (approximately 98%) or epimastigotes (approximately 2%). Bloodstream trypomastigotes cultivated without TI-32 cells underwent the first, but not the 2nd differentiation phase, although occasional epimastogotes were seen (less than 1%). The evidence presented suggests that TI-32 cells produce a labile factor(s) important not only for initiation of the 2nd differentiation phase but also for maintaining the parasites in the trypomastigote stage. The pH of the culture medium was not the initiating factor for the 2nd differentiation phase. Infectivity studies indicated that staphylomastigotes were as infective as blood stream trypomastigotes, but that metacyclic trypomastigotes isolated from culture after the 2nd differentiation phase were slightly more infective than bloodstream forms. Electromicrographs of styphylomastigotes do not provide any evidence of exchange of genetic material between cells.
0.846708
Compositional relatedness of aldehyde reductases from several species.
The amino acid compositions of several monomeric NADPH-dependent aldehyde reductases from a variety of species have been determined and analyzed by the difference index method of Metzger et al. (1968). The difference indexes among mammals range from 4.15 - 6.10 indicating considerable homology. Comparison of chicken aldehyde reductase with mammalian aldehyde reductases gave values in the range 6.8 - 9.9 suggesting a close relationship whereas the difference indexes for the enzymes from fruit fly and Baker's yeast versus vertebrate aldehyde reductases (10.9 - 14.4) indicate more distant relationships. The extent of sequence homology among aldehyde reductases from these species was estimated from a plot of difference index versus percent sequence difference for oxido-reductases of known sequence. From this plot, and using a mammal-chicken divergence time of 300 million years and a mammalian order split of 75 million years, the rate of evolution of aldehyde reductases was calculated to lie in the range 5.8 - 15.6% sequence difference per 100 million years. Comparison with rates of evolution of oligomeric dehydrogenases indicates that aldehyde reductases comprise the most rapidly evolving family of oxido-reductases. This is probably related to the monomericity of aldehyde reductases since there is a direct correlation between the number of subunits and the rate of evolution.
0.892752
Differential antagonism of antiavoidance, cataleptic and ptotic effects of neuroleptics by biperiden.
The interaction between neuroleptics and an anticholinergic, biperiden, in the antiavoidance, catalepsy and ptosis tests was investigated in mice for the purpose of predicting the extrapyramidal side-effects of neuroleptics. The cataleptic effect of most neuroleptics used was antagonized to some extent by biperiden, while the ptotic effect was hardly influenced. The antiavoidance effect of haloperidol, trifluperidol and perphenazine was markedly antagonized and that of chlorpromazine moderately. However, the effect of thioridazine, chlorprothixene, levomepromazine and clozapine was little antagonized. In neuropharmacological tests, haloperidol, trifluperidol and perphenazine exhibited a selective antidopaminergic activity, while chlorprothixene, levomepromazine and clozapine showed antidopaminergic, antiadrenergic and also anticholinergic activities when similar doses were given. These results indicate that biperiden antagonism may be marked in the tests related to the extrapyramidal symptoms and in drugs liable to induce extrapyramidal side effects, however, there would be little or no antagonism in drugs possessing the anticholinergic property and eliciting few extrapyramidal side-effects.
0.897858
[The effect of betadrenol on examination anxiety (author's transl)].
The effect of betadrenol on examination anxiety was tested in a double-blind study simulating "examination situations". The sample consisted of 60 normal students. After a test examination without prior treatment, each subject was given a single dose of either 40 or 100 mg betadrenol, or a benzodiazepine derivative at the recommended dosage, or a placebo. The test was repeated one hour later. Heart rate, blood pressure and skin resistance were measured continually throughout the progressively complicated psychological test. The increase in the heart rate was significantly lower in the betadrenol-treated subjects than in those given benzodiazepine or a placebo. The behaviour of the blood pressure was similar. Significant improvements in subjective condition and skin resistance in response to betadrenol were contrasted with deterioration after benzodiazepine, and no change after placebos. Improvement in mental alertness in the betadrenol group differed significantly from that in the benzodiazepine group, and there was also an improving trend in reactions. This shows that betadrenol can subdue examination anxiety. Betadrenol was far more effective than a benzodiazepine derivative in all the parameters tested, including psychophysical performance relating to control of a motor vehicle.
0.92692
Leishmania in phlebotomid sandflies. VII. On the taxonomic status of Leishmania peruviana, causative agent of Peruvian 'uta', as indicated by its development in the sandfly, Lutzomyia longipalpis.
The name Leishmania peruviana was given by Velez (1913) to the parasite responsible for a form of cutaneous leishmaniasis known as 'uta'; this disease occurs in the Peruvian Andes. Clinical similarities between uta and 'oriental sore', which is caused by Leishmania tropica of the Eastern Hemisphere, have, however, led to the suggestion that uta is simply due to L. tropica, which was introduced into Latin America by African slaves or European immigrants. Leishmania species are divisible into three distinct sections, according to their pattern of development in their natural (phlebotomine) vectors. One of these sections, the PERIPYLARIA, contains the subspecies of Leishmania braziliensis, and is characterized by parasites that undergo a phase of development attached to the wall of the hindgut (pylorus and ileum), in addition to multiplication in the midgut and subsequent invasion of the foregut. Such development is unknown in any other group of leishmaniae, including those groups of the section SUPRAPYLARIA, which includes parasites of the L. tropica complex. Three isolates of L. peruviana were studied in laboratory-bred sandflies, Lutzomyia longipalpis (Lutz & Neiva), and all showed consistent and prolific development of rounded or stumpy flagellates attached to the wall of the hindgut and, in some instances, growth of free, elongate promastigotes throughout the midgut. Development of both L. tropica and L. major, in the same insect, was restricted to massive development of free flagellates in the midgut, up to the cardial valve. From the behaviour of L. peruviana in the sandfly, its slow growth in hamster skin and the small size of its amastigotes, it is concluded that this parasite is (a) distinctly different from both L. tropica and L. major, and (b) closely related to subspecies of L. braziliensis within the section PERIPYLARIA. On this evidence it is also concluded that L. peruviana is indigenous to the American continent. The specific name is best retained for the time being (rather than L. braziliensis peruviana).
0.877642
Lethal synergism between morphine or other narcotic analgesics and propranolol.
Interactions of (+/-)-propranolol HCl with various narcotics were determined in albino rats. The 24-h intraperitoneal (i.p.) LD50 of morphine sulfate + saline was 15--16 times greater than for morphine + propranolol in both sexes although morphine was nearly twice as toxic to males as to females. The potency ratios for LD50's with saline vs. with propranolol were: codeine, 1.9, (+/-)-methadone, 6.0; (-)-alpha-acetylmethadol, 2.8 (72 h). The toxicity of levorphanol also was greatly increased with propranolol, but the dose-effect relationship showed non-parallelism vs. levorphanol + saline. Albino mice and mongrel dogs also showed synergism between morphine and propranolol. Mortality after morphine and propranolol was antagonized by naloxone or naltrexone in rats and mice. The potency ratio in rats for morphine + saline vs. morphine + practolol was 3.5. However, the synergism between propranolol and the narcotics probably was unrelated to beta-adrenergic blocking effects of propranolol because of the apparent equivalence of (+)-, (-)- and (+/-)-propranolol in rats for synergism with morphine.
0.876971
[Treatment of the relapsing dislocation of the patella (author's transl)].
From 1970-1977, twenty-five patients were given surgical treatment for relapsing dislocation of the patella. The mean age of the patients was 22 years. The case material consisted of 18 female and 7 male patients. The average frequency rate of dislocation was three to fifteen times. (Reported from the BB-Accident Hospital Tübingen). The combined surgical method with gracilis muscle restraint described by Krogius, was used in this clinic in view of its traditionally successful application. Additional antepositioning of the patella according to Bandi was effected in intraoperatively discovered retropatellar arthrosis. Relapses of dislocation were reported in two cases. Good postoperative results were obtained in 14 patients, satisfactory results in 5 patients, and an unsatisfactory outcome in three patients. Redislocation was reported twice. Since this disease occurs preferably in juveniles, surgical treatment to prevent further dislocations should be effected well in time to avoid early retropatellar arthrosis. Since dislocations of the patella are frequently adjusted spontaneously without any treatment, critical and detailed anamnesis is imperative in every patient with a distorted knee joint.
0.886529
[Effects of hypoxia on the coronary circulation and myocardial metabolism].
The effects of hypoxia on coronary flow (Qcor) and myocardial metabolism differ according to whether the situation is acute, and transient, or chronic and prolonged (chronic hypoxia at high altitudes). Acute hypoxia induces a marked increase in Qcor which is associated, in the case of severe hypoxia, with the production of lactate and pyruvate in the coronary venous blood, indicating abnormal aerobic metabolism of the myocardium, blocked by the lack of oxygen. A study of the effects of chronic hypoxia at high altitudes (HA) carried out at 3700 metres in 17 normal subjects revealed a significant decrease (of 24 to 28 per cent) in Qcor in comparison with a group of 12 normal subjects studied at sea level, using the same method (method of KETY-SCHMIDT with N2O and tritiated water method). The finding at HA of a decrease in myocardial oxygen consumption for a given external cardiac work load in comparison with the sea level group would suggest an increase in left ventricular work yield. Associated with other favourable changes in the myocardium (increase in terminal and capillary circulation, quantitative and qualitative improvement in the respiratory enzyme chain) the apparently beneficial effects of chronic hypoxia at HA may be suggested as a means for the prevention of coronary disease.
0.904808
Polymorphism at the G6pd and 6Pgd loci in Drosophila melanogaster. III. Developmental and biochemical aspects.
The electrophoretic variants of G6PD and 6PGD isolated from the Bogota Drosophila melanogaster population were characterized developmentally and biochemically. Changes in in vitro enzyme activity during development were comparable to those found for other dehydrogenases: an increase in the larval and adult stage and a decrease in the pupal stage. During the whole life cycle the "S" enzyme of both loci showed a higher activity than the "F" enzyme. MgCl2 had a stimulating effect on the activity of both enzymes whereas their heat stability was decreased. The allozymes of 6PGD had different Vmax's but were comparable with respect to Km values, pH optimum, and stability at 45 C. the allozymes of G6PD showed different Vmax's and differed in stability at 35 C, but had similar Km values and pH optima. As the difference in stability was probably due to differences in molecular structure of the allozymes, the differences in activity found at high pH and high MgCl2 concentration were most probably due to this difference in stability.
0.884044
The effect of reduction of perfusion rate on lactate and oxygen uptake, glucose output and energy supply in the isolated perfused liver of starved rats.
1. Lactate and O2 uptake and glucose output were studied in isolated livers from starved rats at perfusate flow rates varying from 100 to 7% of "normal" (11.25-0.75 ml/min per 100 g body wt.). 2. With moderate diminution of flow rate, lactate and oxygen uptake fell more slowly than would be expected if uptake purely depended on substrate supply. 3. Use of a mathematical model suggests that the intrinsic capacity of the liver for lactate uptake is unaffected until the flow rate falls below 25% of "normal". 4. Some lactate uptake was always observed even at 7% of the "normal" flow rate. 5. At flow rates below 33% of the "normal", lactate was increasingly metabolized by pathways other than gluconeogenesis, which became a progressively less important consumer of available O2. 6. ATP content decreased with diminution of flow rate, but substantially less markedly than did lactate uptake and glucose output. 7. Intracellular pH fell from a mean value of 7.25 at "normal" flow rate to 7.03 at 7% of the "normal" flow rate.
0.893395
The kinetic parameters of trehalase in whole and disrupted mitochondrial preparations from two insects with asynchronous muscle.
The kinetic parameters of trehalase in honey bee and flesh fly mitochondria were compared. The studies were carried out with whole mitochondria and with mitochondria disrupted in various ways and to different degrees. Honey bee mitochondrial trehalase was significantly activated by Lubrol WX treatment (30.0-fold), by high pH treatment (20.8-fold), and by a treatment consisting of 10 passes through a French press (37.9-fold) but not by the other treatments tried (salt, proteases, Waring blender, and sonication), despite the fact that these treatments also disrupted the mitochondria significantly. The activation effect was on the Vmax. The Km value did not change. Simple breakage of either the outer or inner (or both) membranes was not sufficient to activate trehalase from honey bees, which showed that the activation was not an indirect result of a change in the case with which trehalose can pass through the membranes. Honey bee trehalase is the first trehalase from insects with asynchronous muscle which has been shown to be activatable by physical and chemical methods. Flesh fly mitochondrial trehalase behaved quite differently from the honey bee enzyme in that it could not be activated by any of the techniques tried, even when there were significant amounts of disruption.
0.893322
Treatment of hypertension: state of the art in 1979.
1. The results of the Veterans Administration Co-operative Study have been extended by the subsequent clinical trials, which included patients of both sexes and with less vascular disease. The later studies confirm the effectiveness of treatment in preventing most complications except myocardial infarction and sudden death. Furthermore, the lower diastolic blood pressure in which treatment has been shown to have a significant beneficial effect has been lowered from 105 mmHg as indicated by the Veterans Study to 100 mmHg as shown by the much larger Australian trial. The possibility of reducing the incidence of sudden death and fatal myocardial infarction has been suggested by other recent control trials using beta-adrenoreceptor-blocking drugs, an approach that needs further exploration. 2. A number of interesting and useful new drugs have appeared which include tienilic acid, minoxidil, saralasin and captopril, and in addition recent controlled trials have re-emphasized the effectiveness of the old drug, reserpine, when combined with a diuretic. The art of treatment of hypertension therefore appears to be in a healthy state and we should expect more advances in the future.
0.819373
Effect of cell density on energy-dependent calcium uptake by Balb/c 3T3 membranes is independent of protein synthesis and attachment to substratum.
Membranes isolated from subconfluent cultures of Balb/c 3T3 cells have low energy-dependent calcium uptake activity. Replating confluent cells at low density results in a prompt fall of energy-dependent calcium uptake by membrane fractions. The level to which uptake activity falls is a function of the density at which the cells are plated (Moore and Pastan, '77b). To determine if regulation of energy-dependent uptake of calcium by membrane fractions is dependent upon attachment to a substrate and to further characterize conditions that regulate the process, we examined calcium uptake activity of membranes isolated from cells in suspension. With cells in suspension energy-dependent calcium uptake activity of isolated membranes falls promptly if cells are diluted to a low density (less than 10(5) cells/ml) and is a function of cell density. When cells in suspension at low cell densities are concentrated to high cell densities (greater than 2 x 10(6) cells/ml), calcium uptake activity of the isolated membrane fraction is increased as a function of cell density. These changes of membrane calcium uptake activity occur promptly and do not require protein synthesis.
0.903865
Detection of anticapsular antibodies to Bacteroides asaccharolyticus in serum from rabbits and humans by use of an enzyme-linked immunosorbent assay.
A sensitive serologic test, the enzyme-linked immunosorbent assay (ELISA), was used to detect serum IgG antibodies directed specifically to a capsular antigen of Bacteroides asaccharolyticus (previously known as Bacteroides melaninogenicus subspecies asaccharolyticus). Anticapsular IgG was measured in 30 specimens of rabbit serum after the animals were immunized with whole B. asaccharolyticus, the two subspecies of B. melaninogenicus, and several other bacterial species. Species-specific anticapsular IgG was demonstrated (P less than 0.001). Levels of anticapsular IgG greater than control levels were likewise detected in serum from two humans, including one patient who had periodontitis and from whom B. asaccharolyticus was isolated, and a laboratory worker who had extensive exposure over a two-year period to B. asaccharolyticus. The ELISA was found to be a relatively simple, sensitive tool for measurement of serum IgG. Its application to detection of immunoglobulins of other classes, including secretory IgA, is anticipated, provided adequate standardization methods are used.
0.928171
Amines and the rat exocrine pancreas: (1). Effects of receptor blockers on turnover of L-dopa.
The acinar cells of the exocrine pancreas have the capacity of efficiently take up and metabolize L-dopa. In the present study, the metabolism of L-dopa by the exocrine pancreas of the rat and effects of receptor blockers on the metabolism were studied by fluorescent histochemical and chemical methods. After i.v. administration of L-dopa (50 mg/kg), a large amount of dopamine (DA) was detected in the exocrine pancreas, and in the pancreatic juice large amounts of DA and its metabolites. DA-blockers (haloperidol, sulpiride, and pimozide) and alpha-blockers (phenoxybenzamine, and phentolamine) produced a significant increase in the accumulation of DA after administration of L-dopa. On the other hand, beta-blockers (propranolol, and oxprenolol) were without effects. The excretion of DA into the pancreatic juice appeared to be associated with the secretion of zymogen granules, thus DA serves as an indicator of pancreatic secretory activity, especially of enzyme secretion. Because DA- and alpha-blockers produced an increase in the accumulation of DA, dopaminergic and/or alpha-adrenergic mechanisms probably exist in the exocrine pancreas of the rat and these mechanisms modify the enzyme secretion.
0.914823