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Phenothiazine analgesia--fact or fantasy?
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Double-blind clinical trials involving the use of phenothiazines as analgesics or potentiators of analgesics (aspirin, meperidine, morphine sulfate) and adverse effects of phenothiazines are reviewed and evaluated. Promethazine, promazine and propiomazine were not found to possess analgesic or potentiating properties. One chlorpromazine study contained important design and reporting deficiencies which precluded a recommendation for use of chlorpromazine in the treatment of pain. Methotrimeprazine was determined by numerous authors to have analgesic properties; however, most of the studies also were deficient in design or data presented, or both. Adverse reactions to phenothiazines, including hypotension, sedation, drowsiness, extrapyramidal symptoms, tardive dyskinesia, cardiac toxicity and agranulocytosis, are often more common and severe than those attributed to narcotic analgesics. Because of the lack of data supportive of analgesic activity and the adverse reactions associated with phenothiazines, use of these agents in the management of pain should be discouraged. The prophylactic use of phenothiazine for narcotic analgesic-induced emesis also is, in most cases, a questionable practice.
| 36,754
|
Efficacy of antiparkinson agents in preventing antipsychotic-induced extrapyramidal symptoms.
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The types of extrapyramidal syndrome (EPS) reactions produced by antipsychotic agents and the prophylactic use of antiparkinson agents in preventing EPS are reviewed. EPS are classified as akathisias, dystonias, parkinson-like symptoms and tardive dyskinesia, and have a varied incidence reported to range from 10.6 to 100%. Incidence may vary with age, gender, drug and dosage. The prophylactic use of antiparkinson agents to prevent EPS is controversial. Many psychiatrists believe the effect of EPS on patients is more harmful than the side effects of anticholinergics, whereas others believe that because of side effects, increased cost, greater risk to tardive dyskinesia and improper use, the use of antiparkinson agents cannot be justified. Most studies of prophylactic use of antiparkinson agents have lacked adequate control groups, adequate blinding procedures for investigators rating EPS, uniform definitions of EPS, random sampling and careful reporting of group characteristics such as dosage and drugs received. There is a lack of definitive studies of the value of antiparkinson agents in preventing the occurrence of EPS in patients receiving antipsychotics. A large, multicenter study should be undertaken to resolve the issue.
| 36,755
|
Beta-agonists and secretory cell number and intracellular glycoproteins in airway epithelium. The effect of isoproterenol and salbutamol.
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This study describes the effect of systemic administration of the beta-adrenergic agonists isoproterenol and salbutamol on the secretory cell populations in seven regions of rat airway epithelium (three extrapulmonary and four intrapulmonary) and on the size of salivary glands and heart. Isoproterenol (a nonselective beta-adrenergic agonist) significantly increases secretory cell number in all airway regions except the midtrachea; salbutamol (a selective beta 2 agonist) increases secretory cell number only in proximal and peripheral regions. The absolute number of secretory cells is greatest in the most peripheral region after isoproterenol administration and in the most proximal region after salbutamol, although both drugs produce the greatest relative increase at the periphery. In proximal and, particularly, peripheral regions, the increase by isoproterenol (less than 3- and 14-fold, respectively) is greater than by salbutamol (less than 2- and less than 3-fold, respectively). In all airway regions, both drugs modify intracellular glycoprotein in the secretory cell population; within a given region, modification is much the same. In the most proximal region, the population of cells synthesizing only granules of neutral glycoprotein significantly increases while in other regions increase is in cells synthesizing only granules of acid. A significant shift in glycoprotein synthesis occurs whether or not the secretory cell population is increased, which suggests that existing as well as newly appearing cells modify their product. Isoproterenol significantly increases the size of the parotid and submaxillary glands; salbutamol increases the size of the parotid only. Isoproterenol significantly increases the weight of both ventricles of the heart; salbutamol has no such effect.
| 36,762
|
Post-partum sterilisation--an anaesthetic hazard?
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A case of acid aspiration pneumonitis which occurred in the puerperium is described. Gastric aspirate was collected in fifty patients undergoing postpartum sterilisation. Results of pH and volume suggest these patients should be regarded as potential candidates at risk of developing Mendelson's syndrome.
| 36,807
|
Properties of beta-glucan synthetase from Saccharomyces cerevisiae.
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Properties of beta-glucan synthetase from S. cerevisiae were studied. The enzyme exhibited optimal activity at pH 6.7 and 24 C. Km for UDP-glucose was 0.12 mM. Addition of Mg++ or Mn++ stimulated its activity by 60% and 21% respectively. High concentrations of EDTA and hydroxyquinoline were inhibitory. Glucan synthetase was fully active in cell-free extracts. Small concentrations of trypsin or subtilopeptidase A from Bacillus subtilis, caused only a slight increase in glucosyl transferase activity, but larger concentrations destroyed beta-glucan synthetase. Acid proteases were neither stimulatory nor destructive. Thus it seems unlikely that beta-glucan synthetase exists in a zymogen form. Glucan synthetase was unstable. It was inactivated more rapidly at 28 C than at 0 C. The presence of substrate, beta-glucan or the protease inhibitors PMSF, Antipain or Pepstatin A did not protect beta-glucan synthetase from inactivation. Glucan synthetase was not stimulated by addition of cellobiose or beta-glucans. The synthesis of beta-glucans was competitively inhibited by UDP (Ki = 0.45 mM). Glucono-delta-lactone, a known inhibitor of beta-glucosidases was a strong non-competitive inhibitor of beta-glucan synthetase.
| 36,834
|
Development of a quantitative method for the detection of enteroviruses in soil.
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A method is described for efficiently concentrating enteroviruses from soil. Viruses were eluted from soil by mechanical agitation in high pH glycine buffer containing ethylenediaminetetraacetic acid. The eluted viruses were concentrated on a floc that formed de novo upon adjustment of the soil eluate to 0.06 M aluminum chloride and pH 3.5. Viruses not pelleted with the floc were concentrated by adsorption to and elution from membrane filters. This method yielded an average efficiency of 66% recovery from loamy sand soil for four enteroviruses. Virus recovery from soil was consistently high, with samples ranging in size from 25 to 500 g. The method was used successfully to isolate naturally occurring viruses from soil beneath a wastewater land treatment site. Recovery of enteroviruses by this method form different types of soil was dependent on percentage of clay, surface area, and cation exchange capacity. Recovery was not dependent on soil saturation pH or on percentage of organic matter. This method should prove useful for studying enterovirus migration and survival during the land application of domestic sewage.
| 36,845
|
Magnitude of pollution indicator organisms in rural potable water.
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A total of 460 water samples were randomly drawn from the potable water supply sources of rural communities in three counties of South Carolina. About 10% of the population, not incorporated in municipalities, was sampled. The samples were tested for total coliforms, Escherichia coli, and fecal streptococci. Significant levels of these pollution indicator organisms were detected in almost all the water supplies. Total coliforms were the most common, and only 7.5% of the water supplies were uncontaminated. E. coli, considered a reliable indicator of recent and dangerous pollution, was observed in 43% of the water supplies. Statistical analyses indicated that the bacterial populations, especially E. coli, were associated with the supply source depth and its distance from the septic tank. Total coliform counts were also weakly correlated to the pH of the water.
| 36,849
|
pH-induced platelet ultrastructural alterations. A possible mechanism for impaired platelet aggregation.
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After the observation that lavages with alkaline solutions exert a beneficial effect on the bleeding tendency and increase platelet aggregation in patients with intragastric hemorrhage, studies were undertaken to find a relationship between changes of pH and platelet morphology. Transmission and scanning electron microscopy showed that at a pH lower than 7.4, normal human platelets change their internal structure as well as their shape, becoming spheres deprived of pseudopodia. On the other hand, a pH higher than 7.4 induces transformation of platelet internal organelles similar to that caused by thrombin. At an alkaline pH, the platelets develop multiple pseudopodia that facilitate their attachment to each other. These findings may explain the increased platelet aggregation in alkaline medium demonstrated in one of our previous works.
| 36,869
|
Choline kinase and ethanolamine kinase activity in the cytosol of nerve endings from rat forebrain.
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Both choline kinase and ethanolamine kinase are present in the cytosol of nerve endings prepared from rat brain are the products of their action, phosphocholine (84 nmol/g fresh wt. of brain) and phosphoethanolamine (190 nmol/g fresh wt. of brain). In contrast with the enzymes from the cytosol of whole brain, both are as equally active at pH 7.5 as 9.0. Determination of kinase activity in membrane-containing tissue samples at pH9 gives low values because of the activity of alkaline phosphatase. Choline kinase, but not ethanolamine kinase, requires Mg2+ in excess of that required for the formation of the MgATP complex and is inhibited by an excess of free ATP. The Km for choline is 2.6mM and for ethanolamine is 2.2mM. The differing requirements for ATP and Mg2+ and the inhibition of choline kinase, but not ethanolamine kinase, by hemicholinium-3 suggest either the presence of two separate enzymes or two different active sites on the same enzyme.
| 36,885
|
The plastoquinone pool as possible hydrogen pump in photosynthesis.
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The function of the plastoquinone pool as a possible pump for vectorial hydrogen (H+ + e-) transport across the thylakoid membrane has been investigated in isolated spinach chloroplasts. Measurements of three different optical changes reflecting the redox reactions of the plastoquinone, the external H+ uptake and the internal H+ release led to the following conclusions: (1) A stoichiometric coupling of 1 : 1 : 1 between the external H+ uptake, the electron translocation through the plastoquinone pool and the internal H+ release (corrected for H+ release due to H2O oxidation) is valid (pHout = 8, excitation with repetitive flash groups). (2) The rate of electron release from the plastoquinone pool and the rate of proton release into the inner thylakoid space due to far-red illumination are identical over a range of a more than 10-fold variation. These results support the assumption that the protons taken up by the reduced plastoquinone pool are translocated together with the electrons through the pool from the outside to the inside of the membrane. Therefore, the plastoquinone pool might act as a pump for a vectorial hydrogen (H+ + e-) transport. The molecular mechanism is discussed. The differences between this hydrogen pump of chloroplasts and the proton pump of Halobacteria are outlined.
| 36,909
|
Comparison of rat brain membrane antigens by complement mediated release of neurotransmitters from brain fractions using antisera against S-100 and Thy-1.
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Synaptosomal, glial and neuronal fractions were prepared from rat brain and incubated to accumulate radioactively labelled neurotransmitters. Treatment of these fractions with antisera and complement showed that anti-(Thy-1) serum gave good release (50-75% of total uptake) of all neurotransmitters tested from synaptosomal and glial fractions. GABA and glutamate were released from neuronal perikarya, but not norepinephrine or serotonin. Anti-(S-100) serum gave no significant release of any neurotransmitter tested from any of the fractions, although all of them had previously been shown to contain this protein. These results are compatible with the membrane nature of Thy-1 and the mainly soluble nature of S-100 protein. They permit a selection for membrane antigens and neurotransmitters from different brain fractions. Antigenic differences between neuronal and glial plasma membranes were suggested by results with antiserum raised against bulk-isolated rat neuronal perikarya.
| 36,961
|
Lactate administration and fatty liver and kidney syndrome development in biotin-deficient chicks.
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Two experiments were carried out to determine whether administration of lactate to biotin-deficient chicks induced fatty liver and kidney syndrome (FLKS). 2. The results suggest that increased serum lactate concentrations are a consequence of the syndrome rather than a contributory factor in its incidence. 3. The increase in liver lipids of birds affected by FLKS was not associated with an increase in the specific activity of the hepatic lipogenic enzyme acetyl CoA carboxylase accept when birds developed FLKS spontaneously in experiment 2. 4. Some biotin-deficient chicks did not show physical symptoms of deficiency although mean liver biotin concentrations were low (0.31 microgram/g liver).
| 36,966
|
DEAE-cellulose chromatography of creatine kinase isoenzymes--effect of pH and serum.
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DEAE-cellulose chromatography (pH 7.0) of human heart extracts revealed the presence of three creatine kinase isoenzymes. The CK3 (skeletal muscle) isoenzyme was not retained on the column under these conditions. The CK2 (heart) and CK1 (brain) isoenzymes eluted at a conductivity of 5.5 +/- 0.6 m omega-1 and 11.4 +/- 1.2m omega-1, respectively. When DEAE-cellulose chromatography was performed at pH 8.0, CK2 eluted at a slightly higher conductivity, 6.5 m omega-1, whereas CK1 eluted as before 12.0 m omega-1. DEAE-cellulose chromatography of CK2 and CK1 isoenzymes in the presence of serum protein, and serum albumin had no significant effect on the elution of CK2 at pH 7.0 and 7.4, and on the elution of CK1 at pH 7.0 and 8.0 However, serum and serum albumin decreased the affinity of CK2 for DEAE-celluose at pH 8.0, and caused this isoenzyme to elute at a conductivity of 3.0-3.5 m omega-1. The decreased affinity of CK2 for DEAE-cellulose was not due to aggregation of CK2 with albumin or some other serum protein, but was related to the amount of albumin applied to the column.
| 37,001
|
Influence of prazosin on the development of antinuclear antibodies in hypertensive patients.
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A recent publication suggested that antinuclear antibodies (ANA) occur in up to one third of patients treated with the hypotensive drug prazosin (Minipress). We have examined a large group of hypertensive patients and found ANA in 9.7% of 145 patients taking prazosin and in 12.2% of hypertensive patients on any treatment regimen. Excluding patients taking methyldopa (a drug associated with a high ANA incidence), the ANA incidence fell to 6.9% in the prazosin-treated group and to 7.2% of all treated hypertensives. Of over 350 untreated hypertensive patients, 6.0% had ANA. Prazosin did not increase the ANA incidence in patients on or off various drug combinations including beta blockers and diuretics. Analysis of the data by age and sex confirmed our conclusion that prazosin therapy is not accompanied by an increase in ANA.
| 37,015
|
Postischemic brain oxygenation with barbiturate therapy in rats.
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We measured rat brain cortex PO2 (PtO2) with gold microelectrodes (tip diameter 5--10 micron) for up to 2 hours after 16 min of transient global brain ischemia with and without thiopental 90 mg/kg infused iv over 60 min beginning at 5 min postischemia. Seventeen rats were immobilized and mechanically ventilated on 1% halothane in oxygen with continuous monitoring of PtO2, ECG, end-expiratory CO2, rectal temperature, and arterial blood pressure. Global ischemia was induced by trimethaphan hypotension to an MAP of about 50 torr and a neck tourniquet inflated to 1500 torr. Postischemia, nine control rats (11 PtO2 measurements) were untreated and eight rats (8 PtO2 measurements) received thiopental 90 mg/kg. Preischemia, PtO2 values in both groups ranged from less than 5--70 torr with values of greatest frequency between 10 and 15 torr. Postischemia, PtO2 in control rats peaked at 45 +/- 8 (SEM) torr at 20 min. In thiopental treated rats, peak PtO2 was 24 +/- 6 torr at 10 min postischemia. Relative frequency histograms of PtO2 revealed that PtO2 in thiopental treated rats was lower (p less than 0.05) between 15 and 30 min postischemia. The magnitude of the decrease in PtO2 between 105 and 120 min postischemia appeared to correlate directly with the absolute preischemic value (i.e., the higher the preischemic PtO2, the greater the decrease in PtO2 postischemia). These results suggest that thiopental administered in large doses in early postischemia does not improve brain oxygenation secondary to a reduction in brain oxygen consumption. The relevance of the correlation between the magnitude of the fall in PtO2 postischemia and the magnitude of the preischemic value is discussed.
| 37,043
|
Bromocriptine in the treatment of parkinsonism.
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Bromocriptine alters the motor behaviour of animals and improves the motor defect of parkinsonism. Changes in movement are accompanied by biochemical changes in the central nervous system, consistent with the idea that bromocriptine has a dopamine agonist action in the basal ganglia and also in the mesolimbic system and hypothalamus. The overall anti-parkinsonian effect of bromocriptine is similar to that of l-dopa alone or with benserazide (a decarboxylase inhibitor) when optimum doses are used, although individual patients may respond better to 1 drug than to the other.
| 37,066
|
Drugs, alcohol and driving.
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Driving a car is a complex psychomotor and perceptual task which is subject to impairment by many factors. Several workers have studied the potential effects of drugs and alchol in crash production by epidemiological and laboratory studies. Both types of studies have yielded useful data but their limitations must be borne in mind when applying the results in pratice. Alcohol is obviously the most common single cause of traffic accidents. A progessively increased risk with increasing blood alcohol levels is well documented; fatigue and/or drugs increase this risk. Drugs are related much more infrequently to traffic accidents although on the basis of statistics, there is a potential risk with drug use. However, drugs alone are not as important as alcohol. The most significant drugs as regards driving risk are obviously certain antianxiety agents, hypnotics, stimulants, hallucinogens, marihuana, lithium and narcotic analgesics, as well as ganglionic blocking agents, insulin and sulphonylurea derivates. Patients should not drive after taking these drug until they are objectively fully alert and capable. Anticholinergics, antihistamines, antidepressants, antipsychotics, phenybutazone, indomethacin, alpha-methyldopa, and beta-blockers may in some cases cause central side effects (e.g. drowsiness) strong enough to affect driving performance. After starting therapy with these drugs, or after a significant change in dose, driving should be avoided until it is known that unwanted effects do not occur. Psychotropic drugs may enhance the deleterious effect of alcohol, and with most hypnotics there is still an effect the next morning. Some drugs (e.g. anticonvulsants or antiparkinsonian drugs) may make driving safer, but the disease (epilepsy, Parkinsonism, cardiovascular diseases, psychic disorders, etc.) ofter precludes driving. Clinicians should warn their patients about an impairment of driving skills if this is likely to occur due to the drug or the illness concerned.
| 37,067
|
1H nuclear-magnetic-resonance studies of porcine lutropin and its alpha and beta subunits.
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The titration curves of the histidine residues of porcine lutropin and its isolated alpha and beta subunits have been determined by following the pH-dependence of the imidazole C-2 proton resonances. The isolated alpha subunit contains a buried histidine, whose C-2 proton does not exchange with solvent, and which has the unusually low pK of 3.3. In the native hormone all the histidine residues have relatively normal pK values (between 5.7 and 6.2). The four histidine C-2 proton resonances have been assigned to specific residues in the amino-acid sequence, by means of deuterium and tritium exchange experiments on the alpha subunit and its des(92-96) derivative. The histidine with a pK of 3.3 is identified as His-alpha87. The effects of pH on tyrosine and methyl proton resonances show that the titration of His-87 in the isolated alpha subunit is accompanied by a significant conformational change which involves loosening of the protein structure but which is not a normal unfolding transition. The role of conformational changes in the generation of biological activity by subunit association in the glycoprotein hormones is discussed.
| 37,081
|
Transfer in vitro of three benzodiazepines across the human placenta.
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A comparative study of the placental transfer to the foetus of three benzodiazepines was performed using a dual perfusion system of the human placental lobule. A transport fraction was calculated for each benzodiazepine and was compared with reference substances. Relative to antipyrine, the transport fraction of diazepam was 85%, and that of nordiazepam was 84%. The transport fraction of clorazepate represented only 20% of that of tritiated water. The relatively high transfer of diazepam and nordiazepam can be attributed to their high lipid solubility, and the lower transfer of clorazepate is due to its polar nature. It is suggested that in certain instances this benzodiazepine may be of especial value to obstetricians.
| 37,088
|
The effect of rifampicin on norethisterone pharmacokinetics.
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The pharmacokinetics of norethisterone have been studied in 8 women during and one month after treatment with rifampicin (450--600 mg/day). Rifampicin caused a significant reduction in the A.U.C. of a single dose of 1 mg norethisterone from 37.8 +/- 13.1 to 21.9 +/- 5.9 ng/ml X h (p less than 0.01). The plasma norethisterone half life (beta-phase) was also reduced from 6.2 +/- 1.7 to 3.2 +/- 1.0 h (p less than 0.0025). In one additional woman on long term oral contraceptive therapy the 12 hour plasma norethisterone concentration was reduced by rifampicin from 12.3 ng/ml to 2.3 ng/ml. Rifampicin caused a significant increase in antipyrine clearance, 6 beta-hydroxycortisol excretion and plasma gamma-glutamyltranspeptidase activity but there was no significant correlations between changes in these indices of liver microsomal enzyme induction. There was a significant correlation between the percentage increase in antipyrine clearance and the percentage decrease in norethisterone A.U.C. during rifampicin. The changes in norethisterone pharmacokinetics during rifampicin therapy are compatible with the known enzyme inducing effect of rifampicin.
| 37,091
|
[Therapy with antacids].
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The usefulness of antacids in peptic ulcer disease is based on their ability to neutralize secreted gastric acid and to inhibit pepsin activity. The neutralizing capacity (expressed as mval of neutralized hydrochloric acid at a given pH) of different antacids depends upon their chemical composition. To achieve adequate neutralization of stimulated gastric acid secretion antacids have to be taken one and three hours after a meal in a dosage neutralizing 40-80 mval of acid. So far antacids have not been shown to be more effective in relieving ulcer symptoms than placebo. On the contrary an adequate antacid regimen will promote the healing of both gastric and duodenal ulcers in outpatients. Furthermore antacid prophylaxis will reduce the occurrence of acute gastrointestinal bleeding in critically ill patients.
| 37,146
|
Sensitivity of human spermatozoa to various isolation procedures: differences in relation to sperm counts.
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The aim of the present work was to examine the sensitivity of human spermatozoa from oligospermic and normospermic semen samples to manipulations in the course of isolation by generally used procedures. To this end we performed protein and DNA estimations in spermatozoa isolated by procedures differing in rigorousness (washings with Ringer's buffer and a medium containing ficoll) as well as microscopic examinations of washed sediments. The results showed that the washed sediments contained, in addition to spermatozoa, materials containing protein and DNA, possibly deriving from the breakage of sperm cells. These materials increased in amount with the decrease of original sperm counts. We suggest that abnormal spermatozoa, whose percentage usually increases with the severity of oligospermia, are more sensitive to damage than the normal ones.
| 37,177
|
Adaptations in skeletal muscle following strength training.
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Five men were studied before and after 7 wk of isokinetic strength training to determine its effects on muscle enzyme activities and fiber composition. One of the subject's legs was trained using 10 repeated 6-s maximal work bouts, while the other leg performed repeated 30-s maximal knee extension exercise. The total work accomplished by each leg was constant. Training 4 times/wk achieved similar gains in peak torque for both legs at the training velocity (3.14 rad/s) and at slower speeds. Fatigability of the knee extensor muscles, as measured by a 60-s exercise test, was similar in both legs after training. Biopsy specimens showed significant changes in the % of the muscle area composed of type I and IIa fibers as a result of both strength training programs. In terms of muscle enzymes, only the 30 s exercise program resulted in elevated glycolytic, ATP-CP and mitochondrial activities. Despite these changes, none of the parameters measured were found to be related to the gains in either muscle strength or fatigability during maximal isokinetic contractions.
| 37,209
|
Micropuncture determination of pH, PCO2, and total CO2 concentration in accessible structures of the rat renal cortex.
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Previous studies evaluating the mechanism of renal HCO-3 reabsorption have assumed equilibrium between systemic arterial blood and tubular fluid PCO2. We have recently reported that the PCO2 in proximal and distal tubular fluid as well as the stellate vessel significantly exceeded arterial PCO2 by 25.9 +/- 0.92 mm Hg. The purpose of this study was to determine directly, for the first time, pH, PCO1, and total CO2 concentration in the accessible structures of the rat renal cortex with both microelectrodes and microcalorimetry. In addition, the concentrations of chloride and total CO2 were compared in the stellate vessel. The data demonstrate that: (a) values for total [CO2] in both the proximal tubule and stellate vessel calculated from in situ determination of pH and PCO2 closely agree with the measured values for total [CO2]: (b) values for chloride concentration in the stellate vessel are significantly less than the corresponding values in systemic plasma (delta[Cl-] = 5.6 meq/liter); and (c) the rise in [HCO-3] from systemic to stellate vessel plasma closely approximates the observed reciprocal fall in [Cl-] in this structure.
| 37,258
|
Lipoprotein lipase and acid lipase activity in rabbit brain microvessels.
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A preparation of cerebral microvessels was used to demonstrate the presence of lipoprotein lipase and acid lipase activity in the microvasculature of rabbit brain. Microvessels, consisting predominantly of capillaries, small arterioles, and venules, were islated from rabbit brain. Homogenates were assayed for lipolytic activity using a glycerol-stabilized trioleoylglycerol-phospholipid emulsion as substrate. Lipoprotein lipase activity was characterized with this substrate by previously established criteria including an alkaline pH optimum, increased activity in the presence of heparin and heat-inactivated plasma, and reduced activity in the presence of NaCl and protamine sulfate. A different substrate, containing trioleoylglycerol incorporated into phospholipid vesicles, was used to reveal acid lipase activity that was not affected by heparin, plasma, NaCl, or protamine sulfate. Lipoprotein lipase did not show activity with the vesicle preparation as substrate. Intact microvessels, when incubated in the presence of heparin, release lipoprotein lipase into the incubation solution. In contrast, release of acid lipase activity from intact microvessels was not dependent on heparin. The data show the presence of both lipoprotein lipase and acid lipase in brain microvessels and suggest that lipoproteins are metabolized within the cerebral vasculature.
| 37,280
|
Powder mixing in direct compression formulation by ordered and random processes.
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The mixing processes taking place in a two component system involving a cohesive drug, tetracycline and a direct compression vehicle, spray dried lactose (SDL), have been studied by chemical analysis of powder samples and fluorescence microscopy. At a drug concentration level of 0.25% w/w, both random and ordered mixing is taking place. Mixture quality is better (Cv = 1%) using a fine grade of crystalline lactose (CL) than with SDL (Cv = 4%). Using fractionated material, it was found that SDL between 106 and 300 micron gave Cv values up to 12%, whereas with SDL below 106 micron values of 2% were obtained. The poor quality of the SDL mixtures is attributed to ordered unit segregation.
| 37,294
|
Cobaltous chloride-induced hypothermia. II: Pretreatment with sympathoplegics, antihistamines, and narcotic antagonists.
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Body temperature depression was noted in rats, mice, and hamsters following intraperitoneal cobaltous chloride administration (25 mg/kg). Intracerebral cobalt injection elicited hypotermia in rats and mice but not in hamsters. Body temperature depression appeared to be centrally mediated in rats and mice and peripherally mediated in hamsters. The effect of intraperitoneal and intracerebral pretreatment with phentolamine, diphenhydramine, propranolol, cimetidine, and naloxone on the mouse rectal temperature response to cobalt (25 mg/kg ip) was noted. Systemic phentolamine injection (intraperitoneal) did not alter the cobalt response, whereas intracerebral administration partially antagonized cobalt-induced hypothermia, indicating that antagonism was mediated centrally. Pretreatment with propranolol and cimetidine failed to modify the temperature response. Intracerebral diphenhydramine did not influence cobalt hypothermia. However, this agent reduced the cobalt response when given intraperitoneally, presumably through a peripheral inhibitory mechanism. The intracerebral injection of naloxone 30 min prior to cobalt slightly enhanced hypothermia, apparently through a central action. Intracerebral 6-hydroxydopamine injection depleted brain norepinephrine and dopamine but exhibited no apparent influence on cobalt-induced hypothermia.
| 37,317
|
Controlled drug release by polymer dissolution. II: Enzyme-mediated delivery device.
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A novel, closed-loop drug delivery system was developed where the presence or absence of an external compound controls drug delivery from a bioerodible polymer. In the described delivery system, hydrocortisone was incorporated into a n-hexyl half-ester of a methyl vinyl ehter-maleic anhydride copolymer, and the polymer-drug mixture was fabricated into disks. These disks were then coated with a hydrogel containing immobilized urease. In a medium of constant pH and in the absence of external urea, the hydrocortisone release was that normally expected for that polymer at the given pH. With external urea, ammonium bicarbonate and ammonium hydroxide were generated within the hydrogel, which accelerated polymer erosion and drug release. The drug delivery rate increase was proportional to the amount of external urea and was reversible; that is, when external urea was removed, the drug release rate gradually returned to its original value.
| 37,327
|
Operative versus non-operative management of patients with staghorn calculi and neurogenic bladder.
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During the last 5 years 22 patients have been treated at our hospital for staghorn calculi and neurogenic bladder. In 17 patients an operation was done soon after discovery of the calculi, while 5 patients were followed non-operatively. The latter 5 patients had a rapid downhill course marked by sepsis and renal function deterioration and an operation was necessary in 4 of the 5 cases. Injudicious non-operative therapy only prolongs the relentless effects of staghorn calculi in patients with spinal cord pathology.
| 37,347
|
Association of diethylstilbestrol exposure in utero with cryptorchidism, testicular hypoplasia and semen abnormalities.
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Epididymal cysts and/or hypoplastic testes have been found in 31.5 per cent of 308 men exposed to diethylstilbestrol in utero, compared to 7.8 per cent of 307 placebo-exposed controls. Analyses of the spermatozoa have revealed severe pathological changes (Eliasson score greater than 10) in 134 diethylstilbestrol-exposed men (18 per cent) and 87 placebo-exposed men (8 per cent). Further investigation of the 26 diethylstilbestrol-exposed men with testicular hypoplasia has revealed that 65 per cent had a history of cryptorchidism. Only 1 of the 6 placebo-exposed controls with testicular hypoplasia had a history of testicular maldescent. Although none of our Diekmann's lying-in study group has had carcinoma to date one must keep in mind the reported increased risk of testicular carcinoma in testes that are or were cryptorchid. A 25-year-old man who was not part of the study group was treated recently by us for a testicular carcinoma ( mixed anaplastic seminoma plus embryonal cell carcinoma) and he had a history of diethylstilbestrol exposure in utero and cryptorchidism.
| 37,351
|
Unilateral abdominal cryptorchidism.
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The unilateral non-palpable undescended testis is considered separately from other forms of cryptorchidism. It is less likely to be fertile, it is more prone to malignancy and it is more difficult to place. Removal rather than orchiopexy often is in the best interests of the child.
| 37,352
|
[NMR spin-echo study of behaviour dynamics of serum albumin macromolecules in aqueous solutions as a function of pH and ionic strength].
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Alteration of the intermolecular interaction in aqueous solution of human serum albumin (SA) as a result of the increase of ionic strength and pH values brings about the slowing-down of the spin-echo decay curve for protein protons (several times at high SA concentrations). A specific effect of alkaline pH was observed, i.e. the slowing-down of quick component of the spin-echo decay curve. This result taken together with the data on complex spin-echo decay curve, correlation times of protons of different regions is SA and compared with SA isotope exchange data can be explained as a result of the polypeptide chain conformation mobility with frequencies more 10(4) c.p.s. This effect is observed in regions occupying about one half of the SA macromolecule volume.
| 37,429
|
[pH-dependence of the structural and functional properties of lactate dehydrogenase (M4). Indirect cooperativity in lactate dehydrogenase].
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The dependence of structural and functional properties of LDH on pH in the 6.0--9.0 region was investigated. There were no marked deviations of pyruvate reduction initial velocity curves from the Michaelis--Menten equation in a wide range of pyruvate concentrations. It was shown that Vmax changes negligibly in the 6.0--9.0 pH regions, but Km increased markedly with pH elevation. The pK value of 7.8+/-0.1 was obtained for 50% changes of pyruvate binding. The dependence of enzyme inhibition from pH at a high pyruvate concentration (20 mM) was investigated. At pH values above 8.0 pyruvate inhibition disappeared. The dependence of the inhibition degree from pH was estimated as pK 7.8+/-0.1. Hill coefficient (n) calculated from the curves of Km and the degree of substrate inhibition depending on pH was 1.6; n for pyruvate inhibition at pH 7.5 was 2 greater than n greater than 1 for moderate substrate concentrations (1--5 mM) and n approximately 1 for higher concentrations (5--40 mM). The value of n approximately 1 at pH 7.8 was obtained. The model suiting all available data concerning the cooperativity phenomena in LDH during protonation and inhibition by pyruvate is outlined. The model is based on the results indicating the slow isomerisation of LDH in ternary complexes with NADH and pyruvate and the absence of equilibrium on the intermediate stage of reaction.
| 37,431
|
[Electron transfer to hemoproteins. II. pH-dependence of the reduction rate of ferricytochrome c by oxymyoglobin].
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The pH-dependence of the reduction rate of ferricytochrome C by intact and chemically modified oxymyoglobins has been studied. The modification was performed with respect to histidine residues and alpha-aminogroup of N-terminal valine. Two histidine residues of myoglobin, His A10 and His GH1, are shown to take part in the realization of the "active" contact between the molecules in the course of the reaction. The deprotonation of the first residue contributes to the acceleration and that of the second to the reduction of the reaction. The found orientation of the Mb molecules in the "active complex" implies that at any orientation of cytochrome C the distance between the haemes of the both molecules should be more than 30 A. This makes highly probable that a structure-dependent mechanism of electron transfer in the system under study can be proposed.
| 37,434
|
[Effect of alpha and beta receptor blockaders on the degree of glycemia, growth hormone content of blood and catecholamine excretion in insulin-dependent diabetes mellitus].
|
Glycemia, growth hormone level and urinary catecholamine excretion were studied in 182 patients suffering from insulin-dependent diabetes mellitus during insulin therapy alone, and in 33 during treatment with insulin plus alpha- and beta-adrenoblockers. Under the effect of alpha-adrenoblockers glycemia proved to fall in the insulin-dependent patients, without increasing the insulin dose. The STH level diminished in these patients under the effect of alpha-adrenoblockers, even when glycemia persisted at the same level. But beta-adrenoblockers aggravated decompensation and the STH level remained unchanged. alpha and beta-adrenoblockers decreased the urinary adrenaline excretion and elevated noradrenaline, dophamine and DOPA excretion, irrespective of blood glycemia. The authors recommend the use of alpha-adrenoblockers to prevent the necessity of a considerable elevation of insulin doses during compensation in patients with the insulin-resistant form of diabetes mellitus. beta-adrenoblockers are not recommended in diabetes mellitus.
| 37,498
|
Differentiated regions of human placental cell surface associated with attachment of chorionic villi, phagocytosis of maternal erythrocytes and syncytiotrophoblast repair.
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Scanning electron micrographs of human placental cell surface show: (1) Differentiated zones of trophoblast which may be covered by fewer 'microvilli' than the adjacent syncytial cell surface and which extend as a narrow, usually distal protrusion of the chorionic villus. This narrow outgrowth terminates as a fractured end. Presumably since preparations were obtained from therapeutic terminations of pregnancy or Caesarian deliveries these broken ends represent the yield point in the anchoring 'villi' ruptured as a result of surgery. Similar anchoring 'villi' with fractured ends were observed in unfixed material with the use of Nomarski interference contrast microscopy. (2) It appears that, during apparent phagocytic uptake of maternal erythrocytes by syncytiotrophoblast, cell surface lining the forming vacuole still retains an irregular microvillous surface. This observation indicates the potential location of phagocytosis receptors for red blood cells in the placental cell surface. (3) Areas of human placenta which appears to have been damaged and may be undergoing repair exhibit masses of cells with conspicuous microvillar cell surfaces. The origin of these cells is discussed in relation to the usual processes of syncytiotrophoblast formation.
| 37,520
|
Stress distribution in the scapula studied by neutron diffraction.
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High intensity neutron beams provide a method of measuring the preferred orientation of apatite crystals in bulk samples of bone. Measurements at seven different sites on the scapula show that the c axes of the crystals lie preferentially along the directions of pull of the attached muscles. The highest orientation is found at positions under the influence of only a single group of muscles, such as M. teres major or M. infraspinatus. In intermediate regions a multiple distribution of crystals is found, able to withstand stresses in more than one direction. The technique provides a method of assessing the distribution of stress in bones.
| 37,521
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Biochemical evidence of cocarcinogenesis: tumor promoting agent enhances methylnitrosourea activation of rat guanylate cyclase activity.
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The two-stage or cocarcinogenic hypothesis of carcinogenesis involves an initiator (carcinogen) and a promotor (cocarcinogen) being utilized in combination to produce more tumors than either would alone. This theory was tested at the cellular level utilizing Tumor Promoting Agent, 12-0-tetradecanoly-phorbol-13-acetate, (promotor) in combination with submaximal and maximal doses of methylnitrosourea (initiator). Tumor promoting agent, which can cause some tumors itself, was found to enhance the activity of guanylate cyclase (E.C.4.6.1.2.), an enzyme that has been associated with normal and abnormal growth. Tumor promoting agent when utilized in combination with submaximal stimulatory doses of methylnitrosourea had an additive effect on guanylate cyclase activity, but the agent had no further additive effect on guanylate cyclase activation when methylnitrosourea was utilized in maximal stimulatory doses. These results indicate a carcinogen acting alone without a promoter can maximally activate guanylate cyclase and would suggest that at the cellular level a promotor is not absolutely necessary for the changes observed morphologically in canerous cells. The promotor, however, did enhance the enzyme's activity when a submaximal dose of the carcinogen was used indicating that promoting agents, at least biochemically, appear capable of potentially contributing to the development of a cancerous cell.
| 37,562
|
Research in endorphins and schizophrenia.
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It has been suggested that the newly discovered endogenous opiate peptides (called endorphins) might play a role in the symptoms of schizophrenia. The administration of narcotic antagonists provides both a test of the hypothesis and a potential treatment. In this article, we review the methods by which data have been gathered to test endorphin involvement in schizophrenia. Alternative strategies, which hold greater promise of producing conclusive positive or negative evidence, include exploitation of individual differences, use of psychophysiological measures, genetic strategies, and multivariate statistical techniques with larger sample sizes.
| 37,596
|
Incompatibility in vitro and in vivo demonstrated only with saline-suspended red cells.
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An unusual IgG complement-binding antibody was observed in a 64-year-old man prior to surgery. This antibody was detectable by the indirect antiglobulin test when the red cells were suspended in saline, but not when they were suspended in acid citrate dextrose or albumin solutions. Positive reactions were obtained with the patient's own red cells and with the cells of all donors tested. In vivo chromium survival studies showed that donor cells and patient cells, when suspended in saline, had 1-hour survivals of 32 and 46%, respectively. In contrast, donor and patient cells suspended in ACD solution had 1-hour survivals of 77 and 93%, respectively. We concluded that this phenomenon may casue accelerated destruction of saline-suspended cells and should be suspected whenever in vitro incompatibility is noted with red cells suspended in saline.
| 37,652
|
[Metabolism of dicarboxylic amino acids and their amides in bacteria of the genus Citrobacter].
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In 58 Citrobacter strains the pathways of the utilization of dicarbonic amino acids and their amides were studied. These organisms were found to be incapable of decarboxylating glutaminic and asparaginic acids, as well as their amides. All the strains could actively desamidizate asparagine. Not all of these strains showed glutaminase activity. Aspartate-aminotransferase occurred twice as often as alanine-aminotransferase, the level of activity being approximately the same. The Citrobacter strains desamidizated asparaginic acid with great constancy, but only in 1/3 of them this reaction occurred via an aspartase route. The desamidization of asparaginic acid in Citrobacter seemed to proceed in different ways. The desamidization of glutaminic acid was observed only in a part of the strains, and the reaction proceeded less actively.
| 37,683
|
Therapeutical significance of clopimozide in the treatment of chronic psychotic patients.
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This report, which concerns both an open and a double-blind study, describes the activity profile and optimum daily dose of clopimozide (R 29 764) investigated in 40 chronic psychotic patients. The results of the open study indicated that clopimozide represents an equal, if not superior, choice versus the other neuroleptics which the patients had been receiving before the open study. Patients sought more contact with those surrounding them, were less preoccupied with their delusions and hallucinations, and showed a better adapted social behaviour. However, these results were not confirmed by the data from the double-blind study-showing that clopimozide was less superior to the placebo than expected on the basis of the open trial. Two hypotheses are advanced to explain this discrepancy: first, the difference in investigational method and second, possible over-dosage of the drug at an average optimum daily dose of 13.95 mg.
| 37,697
|
A field study of depression in old age.
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The frequency and nature of depression were studied in a random sample of septuagenarians obtained from the Birth Register of the City of Helsinki. Out of 400 newborns in 1903, 261 were pronounced dead in 1973. Of the remaining 139, 106 were examined. Four were chronic mental patients. In the clinical examination of the remaining 102 subjects, 25 were diagnosed as depressive. According to the Beck Depression Inventory 29, or 48.9 percent of the 60 subjects who consented to psychological testing, were depressive. In half of the 25 depressive subjects, chronic disabling disease was the main etiological factor. In the other cases, the main causes were loss of significant personality retirement, and other psychosocial factors involved in aging. Frequency of hypochondria was only 3.9 percent. The prognosis of active treatment was deemed good in the subjects with psychosocial disturbances. Interest in physical exercises and participation in voluntary associations correlated with absence of depression.
| 37,767
|
[The effect of timolol and parasympathicomimetica in the treatment of the elevated intraocular pressure (author's transl)].
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45 patients with ocular hypertension or open-angle glaucoma were tested to see if, and to what extent timolol and three other different parasympathicomimetics (pilocarpine 2%, carbachol 1.5%, aceclydine 2%) produced an supplementary reduction of the intraocular pressure. An equally marked, additional drop in eye pressure was achieved when patients who had been given timolol over an extended period of time, were additionally treated with one dose of pilocarpine 2% or carbachol 1.5%. Aceclydine 2% produced no statistically significant additional effect. Patients who had only been treated with pilocarpine 2% over an extended period of time and then were given one dose of timolol 0.25% produced a drop in eye presure more than double that of those patients who had been primarily treated with timolol and then received pilocarpine or carbachol. These results will be discussed on the basis of the mode of action of the applied medications.
| 37,770
|
A rapid kinetic assay for glucose using glucose dehydrogenase.
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An automated kinetic assay for the determination of glucose in blood is described. The method employs the enzyme glucose dehydrogenase in the presence of mutarotase, with nicotinamide adenine dinucleotide as hydrogen acceptor. The analytical parameters of the method are determined and the flexibility of the method in relation to sample volume and sensitivity is discussed. Finally, the method is compared with automated glucose oxidase and hexokinase procedures.
| 37,797
|
Glutathione reductase in human epidermal tumors. Basal and squamous cell epithelioma, verruca seborrhoeica.
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Glutathione reductase activities, both with NADPH and NADH, were determined in basal and squamous cell epitheliomas, in verrucae seborrhoeicae and in human epidermis. Significantly elevated activites were measured in basal cell epitheliomas and in verrucae seborrhoeicae. Some properties of the enzyme were also investigated.
| 37,807
|
Lower esophageal sphincter function after highly selective vagotomy.
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We evaluate whether highly selective vagotomy (HSV) might disturb functional integrity of the lower esophageal sphincter (LES). Special interest was directed to changes in position of the LES in relation to the diaphragm, LES pressure, and pH reflux pattern. The conditions of 20 patients were evaluated by manometric studies and by 12-hour overnight pH measurements before and 14 days after HSV; five of them were also studied one year after HSV. The results indicate: (1) There is a slight elongation of the LES in the early postoperative phase, which seems to disappear after one year. (2) The position of the diaphragm as measured manometrically by the pressure inversion point descends in relation to the LES 14 days after HSV, and it does not seem to return to its original position after one year. (3) There is no significant change in LES pressure after HSV. (4) There is no increase in reflux after HSV.
| 37,816
|
Pneumococcal disease and its prevention with polyvalent pneumococcal polysaccharide vaccines--a review.
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Polyvalent pneumococcal polysaccharide vaccines have been shown to be safe, immunogenic and efficacious and are becoming available for use in patients at high risk of developing pneumococcal infections. Precise estimates of the role of the pneumococcus in human respiratory disease are difficult to obtain, as this organism is also a frequent commensal of the upper respiratory tract; and as the optimal techniques for the identification and proof of its role are not widely used. Nevertheless, the pneumococcus remains the principal cause of adult pneumonia and paediatric otitis media, and is also an important cause of death from bacteremia and meningitis. At present it seems likely that in Australia these vaccines will be most useful amongst people over the age of 50 years, those with chronic systemic disease, alcoholics, splenectomized individuals and disadvantaged groups such as Australian aborigines, all of whom are particularly susceptible to pneumo-coccal bacteremia which has a considerable mortality rate. The possibility of preventing pneumococcal otitis media in childhood is still being evaluated. Studies of the role played by the various pneumococcal serotypes in Australian populations are urgently needed.
| 37,823
|
A syndrome resembling progressive systemic sclerosis after bone marrow transplantation. A model for scleroderma?
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Six long term survivors of bone marrow transplants developed a syndrome similar to progressive systemic sclerosis (PSS). Cutaneous involvement (6/6), pulmonary disease (6/6), musculoskeletal involvement (4/6), keratoconjunctivitis/positive Schirmer's test (4/6), Raynaud's phenomenon (2/6), and renal and cardiac disease (1/6) were similar to findings in PSS patients. T and B lymphocyte counts and functions were also similar. This PSS-like syndrome, including visceral involvement, after bone marrow transplantation lends support to an immunologic hypothesis of the pathogenesis of progressive systemic sclerosis.
| 37,843
|
Pharmacological studies on 3-[gamma-(p-fluorobenzoyl)propyl]-2,3,4,4a,5,6-hexahydro-1-(H)-pyrazino ]1,2-a] quinoline hydrochloride (compound 69/183). Part III: Assessment of tranquillising activity.
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The tranquillising activity of 3-[gamma-(p-fluorobenzoyl)propyl]-2,3,4,4a,5,6-hexahydro-1-(H)-pyrazino [1, 2-a]quinoline hydrochloride (centpyraquin), a new adrenergic neurone blocking antihypertensive agent, has been evaluated in various laboratory animals. The compound has a calming effect in mice, rats, cats and monkeys. In low doses it reduces the spontaneous motor activity followed in progressively higher doses by hypothermia, ptosis and catalepsy and a taming effect in monkeys and cats. It potentiates pentobarbitone-, hexobarbitone- and ethanol-induced sleep and antagonises amphetamine induced toxicity in mice. It, however, fails to antagonise morphine induced mania and hyperactivity in cats. It blocks conditioned avoidance response in rats at a much lower dose (ED50 = 2.73 mg/kg) than the unconditioned response (ED50 = 10,9 mg/kg). In cats centpyraquin increases the voltage and slows the frequency of cortical EEG discharges. Centpyraquin has the profile of activity of a neuroleptic on the central nervous system.
| 37,855
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Comparison of diazepam and flunitrazepam as adjuncts to general anaesthesia in preventing arousal following surgical stimuli.
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A comparison has been made between the effects of the administration of flunitrazepam 1 mg i.v. and diazepam 10 mg i.v. in 90 female patients undergoing abdominal surgery. The drugs were given immediately before the skin incision as a booster to the induction agent thiopentone. The response to the incision, the quality of anaesthesia and the need for supplementary medication during maintenance were monitored. A standard post-anaesthesia interview was performed to evaluate the amnesic action and patient acceptability. The skin incision caused only slight increase in arterial pressure and heart rate in both groups. Only six patients of the diazepam group reacted to the incision with defensive movements. The overall quality of anaesthesia was better (P less than 0.05) and the need for supplementary doses of pethidine lower (P less than 0.01) in the flunitrazepam group. Recovery was equally good and the duration of sleep after operation was the same in both groups. The frequency of nausea after operation was low. The post-anaesthesia interview revealed that flunitrazepam possesses a more specific anterograde amnesic action than diazepam. Acceptability of the anaesthesia to the patient was equally good in both groups.
| 37,863
|
Possible significance of the pharmacological differentiation of beta-blockers for therapy of hypertension.
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1 Cardioselective and non-selective beta-blockers affect to a different degree several aspects of the circulatory homeostasis. The evidence available in this regard has been evaluated and the possible clinical importance of these differences has been discussed. 2 Venous return in partly regulated by beta-receptors (possibly of the beta 2 type) in the venous resistance vessels. Differences in blockade of venous return by the two classes of beta-blockers may, therefore, influence the degree of increase in left ventricular size, left ventricular end diastolic BPs and stroke volume during beta-blockade. 3 At the first part of the dose-reponse curve, non-selective beta-blockers seem to block more effectively renin release than cardioselective beta-blockers. 4 The direction and the extent to which beta-blockers 'directly' affect total peripheral resistance (TPR), is determined by the resultant of the degree of decrease in TPR by blockade of renin release and the extent of the increase in TPR by blockade of the beta 2-receptors in the arteriolar wall. 5 The clinical relevance of these differences could be that--especially in the low doses range--non-selective beta-blockers may be more 'safe' in patients with compromised cardiac function and may be more appropriate for the therapy of high renin hypertension than cardioselective blockers, whereas the latter may be more appropriate for the majority of hypertensive patients who have low to normal renin hypertension.
| 37,872
|
Identification, characterization and localization of a (Ca2+ + Mg2+)-activated purine nucleoside triphosphate phosphohydrolase from calcifying cartilage.
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A purine nucleoside triphosphate phosphohydrolase (unspecified diphosphate phosphohydrolase, EC 3.6.1.15) was chromatographically separated from the bulk of alkaline phosphatase activity by gel filtration chromatography of butanol and EDTA extracts of fracture callus and bovine epiphyseal cartilage. The callus enzyme differed from alkaline phosphatase in a variety of characteristics. The purine nucleoside triphosphate phosphatase hydrolyzed a more specific group of substrates, required Ca2+ and Mg2+ for optimal activity, remained unaffected by a potent alkaline phosphatase inhibitor, and demonstrated a narrower range of optimal pH for catalytic activity. The enzyme was localized in the microsomal pellet following subcellular fractionation of callus chondrocytes. These characteristics indicate a role for the enzyme in Ca2+ transport.
| 37,914
|
Ultrastructure of the normal human urethra.
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The normal ultrastructure of the prostatic, bulbar and penile urethra in the human is described. The human urethra contains both exocrine and what appear to be endocrine glands. Further study is in progress to define the nature and role of the secretion from these endocrine glands.
| 37,977
|
Peripheral sensory stimulation and the release of transmitter amino acids in vivo from specific regions of cerebral cortex.
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The effects of sensory stimulation on the release of amino acids from sensorimotor and visual cortex have been studied using a superfusion technique. Electrical stimulation of the brachial plexus contralateral to the superfusion cannula increased significantly the release of glutamate and glutamine from the sensorimotor cortex of anaesthetized rats. No clear effect was observed with the other amino acids. Stimulation of the ipsilateral plexus had no effect on glutamate and glutamine release. In unanaesthetized animals stimulation of the contralateral brachial plexus raised the levels of all the amino acids in sensorimotor cortex superfusate. Weak photic stimulation of the eyes of dark-adapted rats increased glutamate release from the visual cortex but caused no significant change in the release of other amino acids. All evoked increases in amino acids release were reversible at the cessation of the stimuli.
| 37,988
|
[Reflections on ten years' experience in the treatment of hemorrhagic colorectitis and Crohn's disease (author's transl)].
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The authors offer a critical review of eight cases of hemorrhagic colorectitis and Crohn's disease (regional ileitis) managed with medical treatments, and eleven like cases treated surgically, during the last ten years. After a discussion of the resources and limitations of medical therapy, the authors describe the various surgical strategies adopted in their cases; they define the possibility of obtaining final cures in Crohn's disease with extended ileocolectomy; and concerning ulcerative forms, they point out the greater efficacy of surgical procedures involving sacrifice of the rectum compared to those in which the terminal segment of the gut is used immediately or later for restoring continuity of the intestinal canal.
| 38,014
|
Metabolic reduction of 1-nitrosoadamantane by rabbit liver microsomes. Properties of a C-nitroso reductase system.
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Washed microsomes from rabbit liver reduced 1-nitrosoadamantane to N-hydroxy-1-aminoadamantane in the presence of a cofactor solution under aerobic conditions; no further reduction of the hydroxylamino metabolite to 1-aminoadamantane (amantadine) occurred. Reduced pyridine nucleotide cofactors are needed for the metabolic reduction. The rate of formation of N-hydroxy-1-aminoadamantane depended upon the microsomal protein content, the time of incubation and the concentration of 1-nitrosoadamantane incubated. The metabolic reduction occurred in air as well as under nitrogen or carbon monoxide. Cupric chloride, mercuric chloride, cysteamine, FAD, and FMN decreased significantly the C-nitroso reductase. The properties of the C-nitroso reductase differed from those of other microsomal reductive pathways.
| 38,089
|
Effects of DMSO, pH, stretch and calcium on the thick filaments in an amphibian smooth muscle.
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Conventional fixation with glutaraldehyde fixatives at pH 7.4 did not preserve/promote thick filaments in Bufo smooth muscle. However, if pH was lowered to 6.0, thick filaments were present and addition of dimethyl sulfoxide (DMSO) led to a greater number of thick filaments. Stretch alone had little effect on the presence of thiber seen. Calcium had little effect on the numbers of thick filaments, but it affected the appearance of the thick filaments. Low calcium (10(-7) M) caused a higher proportion of rod-shaped filaments, while in high calcium (10(-3) M) most thick filaments were ribbons. The great lability of the thick filaments in amphibian smooth muscles makes them ideal for studying factors which affect the appearance of thick filaments in smooth muscle, but it also raises the question of the degree of aggregation of myosin in the living cell.
| 38,120
|
pH and calcium concentration changes in a molluscan egg during development.
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During development, the egg albumen of calcified land snail eggs becomes more and more acid, correlated directly with a constant rise in the calcium concentration of this albumen. It is suggested that the developing embryo releases some acid metabolite and the subsequent change in albumen pH aids in embryonic absorption of the CaCO3 (calcite) egg shell, used for making the embryonic body shell or skeleton (CaCO3 in the form of aragonite).
| 38,136
|
On stability of oral poliovirus vaccines.
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A stabilizer which prevents oral poliovirus from degradation is described. It contains mainly phosphate buffer 0.3 mol, at a pH of 6.7.
| 38,157
|
National Cooperative Crohn's Disease Study: adverse reactions to study drugs.
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Adverse reactions to the drugs employed in the National Cooperative Crohn's Disease Study were sought prospectively at each patient visit and by retrospective review of all patient charts. Prednisone caused evident side effects in over 50% of patients on high-dose suppressive therapy and in approximately one-third of patients on prophylactic dose. Thirty-two percent of patients on high-dose, and 26% on prophylactic-dose prednisone required dose reduction or withdrawal because of side effects. Comparable figures for sulfasalazine were 14% and 12%, and for azathioprine 32% and 20%. The incidence of nausea, vomiting, or anorexia among patients taking sulfasalazine was 46% and 34%, on high and low dose respectively; however, this incidence was no different than that observed among patients taking placebo. These symptoms occasioned withdrawal from the study of only 4% and 3% of patients on high and low doses of sulfasalazine, respectively. Azathioprine produced leukopenia at a dose of 2.5 mg/kg body weight in 15% of patients and the mean white cell count, lymphocyte count, granulocyte count, and hematocrit all fell significantly in patients on this dose. Pancreatitis occurred in 5% of patients taking azathioprine but in no other patients. Sulfasalazine proved to be the safest effective suppressive drug for Crohn's disease. Prednisone toxicity, though substantial, is acceptable in view of its demonstrated suppressive efficacy. Azathioprine was approximately as toxic as prednisone but no more effective than placebo in suppressing active disease. None of the drugs was effective prophylactically, and all showed appreciable long-term toxicity.
| 38,177
|
Azathioprine-related pancreatitis in patients with Crohn's disease.
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Pancreatitis developed in 6 patients in the National Cooperative Crohn's Disease Study. In five of these the diagnosis was confirmed by elevated levels of seum amylase or lipase. All cases were in the 113 patients who received azathioprine and occurred within the first 21 days of treatment. This incidence of pancreatitis was significantly greater than in the patients treated with sulfasalazine, prednisone, or placebo (P less than 0.01).
| 38,178
|
Gastric acid secretion rate and buffer content of the stomach after a rice- and a wheat-based meal in normal subjects and patients with duodenal ulcer.
|
The study describes gastric acid secretory response to a rice-based and a wheat-based meal over a prolonged period of five hours and buffer content of the stomach in five normal and seven duodenal ulcer subjects from the rice-eating eastern Indian population. The results suggest that (1) the meal-mediated gastric acid secretory response in duodenal ulcer subjects is much higher than in the controls, even though the histamine stimulated response is similar, (2) the type of meal, whether rice and fish based or wheat and meat based, does not influence the acid secretory response, and (3) the duodenal ulcer subjects in this area, two hours after a meal, have a buffer capacity similar to the controls.
| 38,191
|
Antacids and peptic ulcer--a reappraisal.
|
Antacids can reduce gastroduodenal acidity for long periods if taken in substantial quantities after food. Their healing effect on gastric ulcer is minimal, if present at all, and easily overwhelmed by the benefit obtained from admission to hospital. Intensive antacid therapy appears effective in healing duodenal ulcer and preventing haemorrhage from stress ulcer, and is comparable in these respects with cimetidine but with a higher incidence of side-effects. Clinical impression strongly suggests that antacids relieve pain in peptic ulcer but objective confirmation is lacking.
| 38,192
|
The reaction of solvated electrons with cytosine, 5-methyl cytosine and 2'-deoxycytidine in squeous solution. The reaction of the electron adduct intermediates with water, p-nitroacetophenone and oxygen. A pulse spectroscopic and pulse conductometric study.
|
Using conductivity detection, pulse radiolysis experiments showed that solvent protonation of the electron adducts of cytosine, 5-methyl cytosine and 2'-deoxycytidine occurs with rate constants k greater than or equal to 2 x 10(4) M-1S-1. The protonated electron adducts transfer an electron to p-nitroactetophenone (PNAP) with rate constants ranging from 3.5 x 10(9) to 5.3 x 10(9) M-1S-1. The transfer is quantitative (G = 2.7), as shown by conductometric and spectroscopic measurements. In the presence of O2 no electron transfer to O2 takes place, implying that O2 adds to the protonated electron adduct radicals. No electron transfer from the H- and OH-adducts of the cytosine derivatives, either to PNAP or to O2, takes place near neutral pH. It is suggested that the differences in the reaction behaviour of the H-adduct radicals and the protonated electron adduct radicals towards PNAP can be accounted for if different radicals are formed by H-addition and protonation of the electron adduct. The H atoms most probably add to the C-5-C-6 double bonds, whereas the electron adducts are protonated at N-3 and/or 0-2.
| 38,222
|
Sources of variation during collaborative evaluation of in vitro dissolution tests for two solid preparations.
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Collaborative in vitro dissolution tests on a sample of commercial tolbutamide tablets and a sample of oxytetracycline capsules were carried out in eight laboratories. The two preparations tested showed differences between the products in release characteristics, particularly in the distintegration phase. This may have caused the difference in the pattern of variance in the two trials. In the case of tolbutamine tablets the value of the repeatability standard deviation was small, and therefore the major contribution to the variance was in the difference between laboratories. With oxytetracycline capsules the major contribution of the variance lies in the random errors common to all laboratories (i.e. the within-laboratory variance). One major source of inter-laboratory viance was identified as the level of vibration at the side of the dissolution flask. Another source of variation was found to be due to using a stated extinction coefficient instead of comparing the absorbances of the samples to those of a solution of a reference substance.
| 38,310
|
Isolation and identification of a fluorophore from ampicillin degradation.
|
A fluorescent impurity in ampicillin has been isolated and identified as 2-hydroxy-3-phenylpyrazine. The product is formed under acidic conditions similar to those employed in some fluorometric assay procedures. The mechanism of the reaction is proposed to involve cyclization by condensation of the penilloaldehyde of ampicillin. The structure was confirmed by independent synthesis.
| 38,311
|
In-vitro differentiation of type A spermatogonia in mouse cryptorchid testis.
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Cryptorchid testes from adult mice were incubated in calf serum-supplemented medium. There was an effective differentiation of adult type A spermatogonia up to the pachytene stage of meiotid division whcih resembled the process of spermatogenesis in vivo. In the absence of calf serum, type A spermatogonia did not differentiate at all. They differentiated when the serum was present for the first day, but was absent for the rest of cultivation. These results indicate that serum is necessary for only the early process of spermatogenesis from type A spermatogonia in vitro and not for the further processes of germ cell differentiation. Type A spermatogonia cultured in serum-free medium retained the ability to differentiate for at least 3 days.
| 38,338
|
Influence of immune status on virus-derived transplantable hepatoma in chickens.
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The transplantable MC-29 virus-derived hepatoma is a suitable model for studying the influence of immune status on virus-derived hepatomas in chickens. It was found that both humoral and cellular immunologic reactions have a role in the pathogenesis of virus-derived hepatomas and that virus-derived hepatomas can be influenced by nonspecific immunostimulation. The lymphoid system was profoundly altered in hepatoma-bearing chickens; this cannot be neglected when studying correlations between immune reactions and carcinogenesis. Profound changes were also observed in protein synthesis and the steroid receptor system of hepatoma-bearing chickens compared to healthy birds; this also complicates the understanding of the role of immune mechanisms in carcinogenesis.
| 38,344
|
Perfusion techniques of the canine pancreas for physiological and secretin response studies.
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In vivo and in situ perfusion techniques of the canine pancreas for physiologic and secretin response to studies are described. We developed these modified techniques to clarify the mechanism of the pancreatic exocrine secretion. An analysis was made of some physiological parameters of the pancreas and our findings were compared with those obtained in secretin stimulation of the pancreas. The composition of secretin induced venous effluent and pancreatic juice was investigated. A decrease of pH, pO2 and (HCO-3) in the venous blood and a temporary efflux of K+ from the cell to the perfusate were observed after secretin stimulation. A temporary decrease of perfusion pressure was observed after secretin stimulation and the change is thought to be due to vascular dilatation. Ultrastructural findings from the pancreas perfused for about 1 hour showed no prominent changes.
| 38,354
|
[The sympathetic neuron: regulation mechanisms for transmitter synthesis, transmitter release, and stimulus response (author's transl)].
|
A great multitude of factors acting at different sites of the afferent sympathetic nerve are capable to modify the magnitude of its stimulus-induced effects. 1) Specific receptors, located at the ganglionic synapse display inhibitory of facilitatory effects on the ganglionic transmission of the nerve impulse. 2) The rate of synthesis of the neurotransmitter noradrenalin is regulated at the level of the tyrosine hydroxylase. Transsynaptic mechanisms adapt the rate of synthesis of noradrenalin to nerve activity and transmitter release. 3) The amount of transmitter released per nerve impulse is controlled by a variety of receptors located presumably presynaptically at neuronal sites. Inhibitory and facilitatory "auto"-receptors stimulated by the released transmitter itself represent a local feed-back control. Similarly receptors for transmitters of cholinergic or serotoninergic neurons as well as autacoid hormones are involved in the local control of noradrenalin release. In addition, kinines, prostaglandins, or compounds like adenosine, some of them released from the target cells by the sympathetic stimuli or delivered by the blood stream are involved in the modulation of stimulus-evoked noradrenalin release. 4) Stimulus responses of the target cells can be modulated by similar mechanisms.
| 38,359
|
[Effect of KH2PO4 on Streptococcus lactis growth and nisin synthesis when the medium is kept at a constant pH].
|
When the pH of the medium was maintained at the level of 6.6--6.8 and the content of KH2PO4 in it was decreased, the biosynthetic activity of Streptococcus lactis, strain MGU, became lower. The culture assimilated low quantities of phosphorus from KH2PO4 at a high concentration of this salt in the medium; presumably, the culture required large quantities of potassium ions. If the pH of the medium is maintained at a constant value, the fermentation can be stopped 21 hr after the beginning of cultivation of Str. lactis, strain MGU.
| 38,379
|
Biological autoxidation. I. Decontrolled iron: an ultimate carcinogen and toxicant: an hypothesis.
|
Ionic iron at physiological pH hydrolyzes into insoluble aggregates, which disperse on slight acidification. Uncontrolled ionic iron promotes autoxidation, which crosslinks biomolecules and produces destructive activated oxygen. Defenses against autoxidative crosslinking include: 1. ferritin, the macromolecular scavenger of iron; 2. metabolic turnover, which prevents irreversible crosslinking through early catabolic degradation and replacement; and 3. enzymatic deactivation of oxygen. I am proposing that the anticrosslinking defenses are defeated by transient actions of metabolic perturbations, toxicants, oxidants and "foreign bodies", which cause oxidative crosslinking of proteins and lipids into irreversible tissue imprint: indigestible bodies containing porous limited-access spaces (LASs). The pores exclude the macromolecular ferritin and the digestive and antiautoxidation enzymes but admit ionic iron which, sheltered from ferritin, accumulates into decontrolled-iron pathogen (DIP). DIP utilizes the energy of ambient pH fluctuations to erupt from the LAS, swamp the available ferritin, poison the surroundings, catalyze autoxidation and crosslink cell components into additional LAS carriers. With time and sufficient promotion by pH fluctuations or metal-complexing agents, DIP and LAS expand. DIP injures through heavy-metal inhibition of life processes and catalysis of autoxidation. Typically, carcinogenic initiators are protein denaturants, cell poisons, "foreign bodies" and autoxidation catalysts. These are DIP-initiating properties, and DIP may be a preneoplastic stage of carcinogenesis. A DIP-model interpretation is given for the growth of asbestos bodies. DIP is an inorganic parasite. It may envelope and attack phagocytized particles.
| 38,381
|
Description and application of a personal ultraviolet dosimeter: a review of preliminary studies.
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Preliminary work on a dosimeter suitable for measuring UVR exposure on individual persons is described. It is based on the use of polysulfone film which, on exposure, shows a change in absorbance that is determined spectrophotometrically. The results of studies of groups of persons with vastly different degrees of solar exposure, e.g., outdoor and indoor workers and geriatric patients, and psychiatric patients with photosensitivity from phenothiazine drugs are presented. We consider the dosimeter may also be suitable for epidemiologic studies in sunlight-induced skin cancer.
| 38,404
|
Fundamental difference between the molecular interactions of agonists and antagonists with the beta-adrenergic receptor.
|
Antagonist binding to the beta-adrenergic receptor is largely entropy driven, with only a small enthalpy component. The binding of agonists, on the other hand, is associated with a large decrease in enthalpy which permits a highly unfavourable decrease in entropy. The thermodynamic differences between the binding of agonists and antagonists may provide new insights into the molecular basis for hormone stimulation of adenylate cyclase activity.
| 38,405
|
Substance P: model studies of its binding to phospholipids.
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1. The partition of substance P (SP) between buffer solutions (pH 1.6--7.8) and an organic, phospholipid (phosphatidyl serine, phosphatidyl ethanolamine, phosphatidyl inositol and phosphatidyl choline) containing phase (chloroform:methanol 2:1) was studied. 2. The binding of SP to phosphatidyl serine, phosphatidyl ethanolamine and phosphatidyl inositol was lowest at pH 2 and increased with pH. The binding to phosphatidyl choline was much smaller and less dependent on pH. 3. In contrast to the basic peptide SP (pI 10.5), physalaemin (pI 7.0) did not show any binding to phospholipids at any investigated pH value which underlines the importance of a basic group in the peptide for its binding. 4. The high affinity (KD = 0.1 microM) and capacity of 44 pmol SP/microgram phosphatidyl serine and 48 pmol SP/microgram phosphatidyl ethanolamine at pH 7.2 under conditions of saturation contrasted with the very low binding of SP to phosphatidyl inositol or phosphatidyl choline. Ionic bindings between the basic peptide and phosphatidyl serine or phosphatidyl ethanolamine are regarded to be predominant, although other binding forces cannot be excluded. 5. There was a concentration-dependent reduction in the binding of SP to phosphatidyl serine or phosphatidyl ethanolamine by Na+ and Ca2+, whereas K+ showed hardly any effect at physiological concentrations. 6. The model studies served to consider the possibilities of the binding of a basic peptide to lipid storage or receptor sites.
| 38,406
|
Etonitazene as a reinforcer for rats: increased etonitazene-reinforced behavior due to food deprivation.
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Etonitazene-reinforced performance of rats was increased by food deprivation and decreased by food satiation. These changes were not due to general increases in either activity or liquid intake.
| 38,472
|
The effects of psychomotor stimulants on single-spatial alternation behavior in dogs.
|
Dogs were trained to pedal press for drinking water in a noncued, single-spatial alternation task. After the dogs were exhibiting stable performance at or above predetermined criteria levels, they were given three doses of four different drugs (methylphenidate, 0.2, 0.4, and 0.8 mg/kg; d-amphetamine, 0.15, 0.3 and 0.6 mg/kg; cocaine, 0.5, 1, and 2 mg/kg; and phenmetrazine, 0.6, 1.2 and 2.4 mg/kg). In general, all four drugs produced similar changes in performance. The number of correct responses was an especially sensitive indicator of drug effects. All four drugs also produced significant increases in both the average response latency and total session duration, but there were few significant changes in either the total number of responses or number of intertrial interval responses. Relative to d-amphetamine, the potencies of cocaine and phenmetrazine, but not methylphenidate, were generally higher for the measures of single-spatial alternation than for self-administration.
| 38,475
|
[Physiopathological and clinical aspects of Parkinson disease. Current problems].
|
Some interpretative hypotheses of the most important symptoms of Parkinson's disease are formulated, on the ground of acquired neurohistopathologic elements and in the light of new observations of experimental neuro-physiology. The possible role of the inferior olivary body in the genesis of parkinsonian tremor is pointed out. The psycho-behavioural disorders and among these the severe weakness of pulsional control and the scanty elaboration of the affective-emotional motivation would be in relation, according to the Authors, to the involvement of the pallido-habenular pathways and the habenuloreticular midbrain outflow (limbic midbrain area).
| 38,498
|
[Kinetics of action of Vectarion. Ventilatory chemo-stimulant (author's transl)].
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Vectarion has a powerful respiratory stimulant effect in animals and in man which is manifested by a significant and lasting increase in ventilation, as shown by a marked lowering of arterial P. CO2 and an increase in blood pH. This activity is maintained in dogs with experimental alkalosis or acidosis as well as during morphine or oxygen-induced respiratory depression. This respiratory stimulating action originates at the level of the aortic and carotid chemo-receptors: this explains why Vectarion is devoid of any epileptogenic risk. The aim of the present study was to demonstrate the peak of activity and duration of action of an intravenous perfusion of Vectarion, in such a way as to be able to plan administration all through the day and night.
| 38,508
|
[Therapeutical trial in recovery room (author's transl)].
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During a limited period of time, the authors have systematically administered tiapride to all patients in the immediate post-operative phase presenting with: nausea, vomiting, pain. Intravenous injection of a single dose of 400 mg of tiapride produces: a strong anti-emetic action; an inconstant analgesic action, but very interesting for it is not accompanied with adverse effects.
| 38,511
|
Influence of long-term citro-soda ingestion on acid-base balance and blood gases.
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Citro-Soda (Abbott), 4 gram every 6 hours, was administered orally over a period of 8 weeks to 20 healthy female volunteers, and its influence on acid-base, urinary pH and other biochemical parameters was assessed. The mean urinary pH increased from a basal value of 6,0 to 7,4 after 7 days, and to 7,7 after 8 weeks. Blood pH increased significantly during the first 2 weeks only, and then returned to basal values. Likewise, the base excess and standard bicarbonate values increased significantly during the first 2 weeks only. The PO2 and PCO2 remained within normal limits for the duration of the trial. Electrolyte values and liver and kidney function showed no abnormality. Thus, in subjects with normal renal function, Citro-Soda appears to be safe for long-term use in a dosage adequate for sustained urinary alkalinization.
| 38,519
|
In vitro study of phenothiazine effects on urinary bladder.
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Clinical observations suggest that long-term phenothiazine therapy can cause urinary retention and stress incontinence. The phenothiazines, chlorpromazine and perchlorperazine, depress bladder smooth muscle activity in vitro by depressing bladder smooth muscle activity directly and by a peripheral cholinergic blocking action.
| 38,553
|
[Properties of amylase immobilized on aerosil derivatives].
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The properties of three preparations of alpha-amylase immobilized on aminoaerosil by 2,4-toluylenediisocyanate and N,N'-dicyclohexylcarbodiimide as well as on carboxyaerosil by N,N'-dicyclohexylcarbodiimide were compared with the properties of soluble enzyme. Under immobilization the pH-effect and pH-stability zones of amylase are 0.5--1.0 pH units shifted towards the alkaline region. The preparations in which the enzyme is bound with the matrix through the amine groups on carboxyaerosil by N,N'-dicyclohexylcarbodiimide and on aminoaerosil by 2,4 toluylenediisocyanate are the most stable at 50 degrees C and to the EDTA effect. The preparation obtained by means of 2,4-toluylenediisocyanate contains a greater amount of the bound protein, is more active and stable.
| 38,550
|
[Relationship between interhemispheric irradiation of excitation and the individual characteristics of the animal].
|
The changes in irradiation coefficient (the ratio between the value of secretion resulting from interhemispheric irradiation of secretion and the main one secreted on the side of excitation evaluated in per cent) were studied in norm and under different functional loads in dogs with exposed symmetrical parts of the tongue following the method of K. S. Abuladse. It is shown that dogs with low and mean level of irradiation of excitation have good mobility of nervous processes and rapid excitation in homonomous structures whereas dogs with high coefficient of irradiation demonstrated inert nervous processes and were not able to show a clear one-way reaction during interhemispheric interaction. A group of dogs with sharply pronounced asymmetry in coefficient of irradiation to the right and to the left is described. This description permitted an assumption about functional heterogeneity of the hemispheres. The obtained data showed that the character of interhemispheric irradiation is determined by individual characteristics of animals.
| 38,585
|
[Changes in alkaline and acid proteins in a chronic epileptiform focus].
|
The acid and alkaline proteins were studied histochemically in neurons of the mirror epileptiform focus (frontal-parietal cortex of rats) on the 11th and 63rd days following cobalt implantation. A specific localization of such proteins was established. During experiments alkaline proteins demonstrated more marked changes than acid ones. The conclusion is made that alkaline proteins play an important role in the protein metabolism of neurons in an epileptiform focus.
| 38,615
|
[Neuromediators and neuromodulators. Evolution of compounds and the evolution of hypotheses].
|
Probable peculiarities of evolution of neurotransmitters (NM) and neuromodulators (NR) of various types are discussed. The hypothesis of higher evolutionary rate of peptide NM and NR, and of more diverse possibilities of the formation of this type of NM and NR is suggested. Monomolecular MN and NR are presumably more conservative, although they exhibit some advantage with respect to strict differentiation of the systems of synthesis and degradation. Probably, the most ancient NM and NR are presented by such compounds as peptides, some amino acids, and ATP.
| 38,612
|
Diabetes-induced alterations of autonomic nerve function in the cat.
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The susceptibility to competitive ganglionic blocking agents such as hexamethonium (C6), tetraethylammonium bromide (TEAB), mecamylamine and d-tubocurarine (d-TC), of the superior cervical ganglion in cats with pancreatectomy and spontaneous diabetes or in animals treated with contrainsular drugs such as cortisone or dihydrochlorothiazide, was found to be decreased as compared to the reactivity of normal controls. The increased tolerance to ganglioplegics was not correlated with the elevation of the blood sugar level, and proved to be resistant to an acute administration of insulin. The results could not be explained by a decrease in the specific cholinesterase activity of the ganglionic tissue due to diabetes. Alteration of the peripheral autonomic synaptic transmission may be an early sign of diabetic neuropathy.
| 38,632
|
Inhibitory effect on gastric motility of chloroquine and mepacrine.
|
Measured on isolated rat-stomach fundus strips, the isolated cervical sympathetic trunk, and on the superior cervical ganglion, chloroquine and mepacrine have parasympatholytic, spasmolytic, ganglionic blocking and local anaesthetic effects. On rising the doses these manifest themselves in a given sequence. On the basis of this fact it is concluded that the inhibition of gastric motility by chloroquine and mepacrine in the rat, is based on the parasympatholytic property of the drugs in question.
| 38,633
|
Neurotransmitters and neuromodulators and their mediation by cyclic nucleotides.
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An effort has been made here to devise criteria allowing discrimination between neurotransmitters, modulators and mediators. However, after consideration of several technical pitfalls in studies of these criteria, and examination of the properties of two examples of neuroactive agents (norepinephrine and endorphins) often referred to as "modulators", it is still difficult to classify these agents in all cases. Thus, in most central targets where NE-fibers are known to terminate, the synaptic actions of NE appear to have properties of both a neuromodulator and a neurotransmitter. Although much more research needs to be pursued, the opioid peptides may be neuromodulators for some neurons (spinal cord neurons) and neurotransmitters for others (myenteric plexus and spinal cord neurons). It may be that classification of such peptide agonists will need to be done on a cell-by-cell basis, with the endogenous peptides subserving a multi-faceted role in central and peripheral neuronal communication. As more and more endogenous ligands and transmitter-like substances are extracted from brain, it begins to appear that the language of neuronal communication is much richer than originally imagined from responses of spinal neurons to the fast-acting classical neurotransmitters. Indeed, it may evolve that the "deviant" forms of communication or transmission are more the rule than the exception. In the final analysis, each neurotransmitter may possess its own "fingerprint" of holistic actions attesting to the unique individuality of neuron types and their neurotransmitters. Such individualities might be expected to accomplish more sophisticated integrative operations, and hence behaviors, than could simple rapid "yes" or "no" messages.
| 38,646
|
The protective effect of a new agent, ketotifen syrup, in the treatment of childhood asthma.
|
Twenty-two children with perennial extrinsic allergic asthma participated in a double-blinded, controlled, cross-over study of Ketotifen syrup during a 2 x 6-week period. The placebo was identical with the active drug in taste, colour, and consistency. The dosage level was, on weight basis, a little higher than the standard dosage for adults. The double-blinded investigation was supplemented with a 1 2-week open study of the tolerance for Ketotifen. This study also involved 22 patients, 12 new ones, and 10 from the double-blind study. The study showed Ketotifen to have no effect on changes in lung function (peak flow), on reduction in frequency of asthmatic attacks, or on consumption of additional medicine. The tolerance for Ketotifen was good, but physicians are advised to watch for increases in weight and decreases in blood pressure during tests on children which involve higher dosage levels.
| 38,678
|
[Experimental hepatic ischemia].
|
Total clamping of the hepatic pedicle was performed for a period of two hours in the normothermic pig. During this time an external pulsed spleno-jugular shunt ensured effective-portal decompression. Under such conditions, the biological and histological consequences of this ischaemia were minimal and perfectly compatible with survival. This would suggest that the clinical syndrome of "shock liver" above all reflects splanchnic impairment.
| 38,702
|
[Histopathology of the liver in shock].
|
Microscopic lesions in shock liver, examined in biopsy specimens from 20 patients, are characterised by elective involvement of the hepatic parenchyma inthe peripheral zones of the acini, with necrosis and cell loss in approximately half the cases. The particular appearance of the degenerative lesions of the hepatocytes ("ischaemic atrophy" and tumefaction, monocellular necrosis), the absence of any change in the reticulin fibres, the minimal leucocytic reaction and the absence of any damage to the portal spaces should make it possible to identify histologically the ischaemic aetiology of peri-acinar hepatic lesions.
| 38,713
|
[Chronic urticaria. Etiologic and therapeutic evaluation of 150 cases. (author's transl)].
|
The study of one hundred and fifty cases of chronic urticaria observed, gave the following results: higher female frequency, usual beginning at adult age, relative absence of digestive problems. For the last of these results we nevertheless noted numerous insignificant functional features, a few examples of colitis, a number of cases of non-functioning gall-bladder. Frequency of sensitivity to foods, preservatives, colouring agents, medical substances, principally shown by provocation tests (the latter present a considerable interest, and merit frequent use); importance of bacterian, mycotic, parasitic origins; little importance of atopy; frequency of minor psychogenic disorders. A contributing role might be played by spasmophily. The therapy includes the following basic treatment; antihistaminic drugs (mainly hydroxyzine hydrochloride and cyproheptadine hydrochloride) and a diet which eliminates recognized urticaria causing foods. In addition, a supplementary treatment destined to eliminate the factors shown to be responsible for the outbreak, must be prescribed.
| 38,729
|
The beta-glucosidase from Botryodiplodia theobromae. Mechanism of enzyme-catalysed reactions.
|
The effects of pH and temperature on Michaelis constant (Km) and maximum velocity (Vmax.) and of NaCl on the activity of the high-molecular-weight beta-glucosidase (beta-D-glucoside glucohydrolase EC 3.2.1.21) from cultures of Botryodiplodia theobromae Pat. have been studied. 2. Donor binding and inhibition of activity by glucose were dependent on the ionization of a group (pK 6.0) that appeared to be an imidazole group. 3. Catalytic activity and the stimulation of activity by glycerol were dependent on the ionization of two groups, which appeared to be a carboxy group and an imidazole group. 4. The Arrhenius activation energy (Ea) calculated from results obtained at pH 4.0 and 5.0 was about 45--46kJ.mol-1. 5. The enthalpies (delta H0) calculated from results obtained at pH 4.0 and 5.0 were similar (about -4kJ.mol-1), whereas at pH 6.5 the value was about -33kJ.mol-1. 6. The entropies (delta S0) calculated from these results at 37 degrees C were -21, -22 and -118J.K-1.mol-1 at pH 4.0, 5.0 and 6.5 respectively. A low concentration of NaCl (16.6 mM) stimulated enzymic activity and decreased the Km for the donor, whereas high concentrations (up to 500 mM) inhibited enzymic activity, increased the Km and had no effect on Vmax. 8. Plots of initial velocity data obtained in the presence of dioxan as 1/v against the ratio of the molar concentration of dioxan to that of water were linear. 9. The results are discussed in terms of the enzyme mechanism.
| 38,775
|
Factors affecting the activity and stability of the palmitoyl-coenzyme A hydrolase of rat brain.
|
Palmitoyl-CoA hydrolase (EC 3.1.2.2) catalyses the irreversible hydrolysis of long-chain acyl-CoA thioesters. This enzyme is found primarily in the postmicrosomal supernatant fraction prepared from homogenates of rat brain. Either of two forms of the hydrolase, a lower-molecular-weight species of approx. 70000 or a higher-molecular-weight species of approx. 130000 can be isolated by gel filtration. The higher-molecular-weight form is obtained from columns of Sephadex G-200 eluted with buffer containing 10mum-palmitoyl-CoA or 20% (v/v) glycerol, whereas the lower-molecular-weight form is obtained when the eluting buffer does not contain palmitoyl-CoA or glycerol. The two forms of the hydrolase have the same pH optimum of 7.5, are equally sensitive to the thiol-blocking reagents p-hydroxymercuribenzoate, HgCl(2), and 5,5'-dithiobis-(2-nitrobenzoic acid), and exhibit the same K(m) (1.8mum) with palmitoyl-CoA as substrate. The two forms differ in the availability or reactivity of certain external thiol groups, as determined by covalent chromatography with activated thiol Sepharose. Dilute solutions of the lower-molecular-weight form of the hydrolase rapidly lose activity (50% in 60min at 0 degrees C), but there is no change in the K(m) with palmitoyl-CoA as substrate during this progressive inactivation. Dilutions of the hydrolase in buffer containing 10mum-palmitoyl-CoA retain full activity. However, addition of palmitoyl-CoA to solutions of the lower-molecular-weight form will not restore previously lost hydrolase activity. The evidence supports the conclusion that the substrate palmitoyl-CoA promotes the formation of a relatively stable dimer from two unstable subunits. This process may not be reversible, since the removal of palmitoyl-CoA or glycerol from solutions of the higher-molecular-weight form does not result in the appearance of the lower-molecular-weight form of the hydrolase.
| 38,776
|
[Norepinephrine turnover under neuroleptic treatment of schizophrenic syndromes (author's transl)].
|
In 45 psychotic in-patients with the paranoid-hallucinatory syndrome, the psychopathology, the extrapyramidal motor disturbances and 3-methoxy-4-hydroxy-phenylethyleneglycol (MHPG) in CSF were investigated. A 15-day treatment with haloperidol induced significant increase of MHPG in CSF; after 10 days clozapine treatment MHPG was significantly reduced. 10 days later the normal values were reached again. The investigation of MHPG in CSF under treatment with neuroleptics showed no correlation between antipsychotic activity and the turnover of central norepinephrine.
| 38,809
|
Membrane damage by a toxin from the sea anemone Stoichactis helianthus. I. Formation of transmembrane channels in lipid bilayers.
|
The addition of nanomolar amounts of a toxin preparation derived from the sea anemone Stoichactis helianthus to black lipid membranes increases their electrical conductance by one million-fold. In addition, the membranes become permeable predominantly to monovalent cations. The elevated bilayer conductance is voltage-dependent, and the current-voltage curves of these bilayers display rectification as well as a region of negative resistance. The membrane activity of the toxin is proportional to the third power of its concentration, and at very low concentrations the membrane conductance increases in discrete uniform steps. These observations indicate that the mechanism of toxin action involves the formation of transmembrane channels constructed by the aggregation of protein molecules which are inserted in the bilayer. The voltage-dependent membrane conductance arises from two distinct channel characteristics: (1) the unit conductance of individual channels is dependent on the polarity of applied voltage; (2) the number of ion-conducting channels is influenced by the polarity as well as the magnitude of applied potential. It is believed that these effects are due to the influence of an electric field on the insertion of toxin molecules into the bilayer or on their subsequent association with each other to produce channels. Partial chemical characterization of the toxin material has shown that the membrane active factor is a basic protein with a molecular weight of 17,500.
| 38,841
|
Characterization of a C21 neutral steroid hormone transforming enzyme, 21-dehydroxylase, in crude cell extracts of Eubacterium lentum.
|
A strain of the obligate anaerobe, Eubacterium lentum, isolated from human feces, catalyzes the 21-dehydroxylation of 11-deoxycorticosterone to progesterone. A quantitative radiochromatographic assay was developed to measure 21-dehydroxylase activity in cell extracts. Maximum enzyme activity in cell extracts required both a reduced pyridine nucleotide and an oxidized flavin coenzyme. However, photochemically reduced flavin (FMNH2) could replace the requirement for NAD(P)H plus oxidized flavin. NAD(P)H : flavin (either FMN or FAD) oxidoreductase activity was detected spectrophotometrically in cell extracts assayed under anaerobic conditions. 21-Dehydroxylase was active from pH 5.4 to 8.5 with an apparent optimum between 6.4 and 6.8 using mixtures of NADH plus FMN as coenzymes. The substrate concentration at half-maximal reaction velocity was 8.0 microM and a specific acitivity of 5.8 nmol [3H]progesterone formed . h-1 . mg-1 protein was determined using [3th]deoxycorticosterone as substrate. Atabrine, rotenone, acriflavin, and 2,4-dinitrophenol (all at 1 mM) inhibited 21-dehydroxylase activity in cell extracts by 25, 24, 35 and 84%, respectively. These results suggest that 21-dehydrogenase may be coupled to a NAD(P)H : flavin oxidoreductase system in E. lentum.
| 38,850
|
Bioconversion of wheat straw and wheat straw components into single-cell protein.
|
Several fungi (Aspergillus niger, A. terreus, Cochliobolus specifer, Myrothecium verrucaria, Rhizoctonia solani, Spicaria fusispora, Penicillium sp., and Gliocladium sp.) were isolated from decomposing wheat straw and tested for their ability to utilize whole straw and its components, holocellulose (hemicellulose and cellulose) and cellulose, for the production of single-cell protein (SCP). It was found that C. specifer was the most efficient fungus for protein synthesis with the three substrates. Using potassium nitrate as N source in mixtures of 0.04 g N/g substrate (0.04% wt./vol.) at pH 4.5, it was found that incubation periods of 3, 4, and 5 days were optimal for protein production on cellulose and holocellulose fractions, and whole straw, respectively. Whole native straw was found to be the most recalcitrant to bioconversion into SCP; however, protein production was almost doubled when the lignin component was removed using a mixture of sodium chlorite and acetic acid.
| 38,899
|
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