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Biomedical subjects

J Breuer

Publications and source records attributed to J Breuer.

At least 145 records · Page 8Linked to original sources
PubMed1986

Social, toxicological and meteorological data on suicide attempts.

A sample of 151 patients, admitted to an Intensive Care Unit after attempted suicide by poisoning was analysed with regard to age, drugs consumed, possible causal factors and influence of weather. The German Weather Service provided the meteorological data. Mean age of the patients was 37.6 years. The patients had taken barbiturates, aggressive chemicals, tranquillizers or a combination of drugs (47%). Alcohol had been taken in addition to the drugs in 24%, which might indicate a trigger function. The main provoking causes for the suicide attempts were conflicts in partnerships and occupational problems. Some 15% of the patients had previously diagnosed psychiatric disorders. There was a significant positive correlation between the time of attempted suicide and the weather parameters "stable upslide, labile upslide, fog, thunderstorm, warm air, upslide and weather drier than on the 2 preceding days". Significantly fewer attempts than expected occurred with "low pressure and trough situation, labile ground layer-upslide above, subsidence or downslide motion". Apart from individual provoking factors, such as the reaction to conflicts and the spectrum of reactions, exogenous factors like weather must be considered as important for the timing of suicide attempts. These results may be of relevance for suicide prevention.

Adolescent↗
PubMed1986

No evidence for serotonergic-adrenergic interactions in the canine total cardiovascular system.

Possible in vivo interactions of serotonin and noradrenaline were investigated in 7 anesthetized mongrel dogs. The hemodynamic effects of three different doses of serotonin (10, 50 and 100 micrograms/kg/min) were analyzed with and without noradrenaline treatment (0.05-0.1 micrograms/kg/min). There were no significant differences in peripheral and cardiac responses between the pure serotonin effect and the hemodynamic effects of a parallel serotonin-noradrenaline infusion. The discussed amplifying effect of serotonin on the adrenergic system could not be observed in the total canine cardiovascular system.

Animals↗
PubMed1986

[Determination of enzyme activities in urine of patients with calcium oxalate calculi].

The catalytic activity of lactate dehydrogenase, gamma-glutamyltransferase, alkaline phosphatase, alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase has been measured in 24 h urines of patients with a calcium oxalate calculus (9 men, 11 women) and has been compared with those of a reference collective (11 men, 10 women). The diagnostic sensitivity and the diagnostic specificity have been calculated according to four different discrimination methods in which the diagnostic sensitivity lies between 65% and 100%, the diagnostic specificity between 72% and 100%. Within the reference group there was a correlation between the excretion of the three brush-border enzymes, whereas within the group of patients only a correlation between gamma-glutamyltransferase and N-acetyl-beta-D-glucosaminidase was observed. From this pathophysiological conclusions can be drawn.

Acetylglucosaminidase↗
PubMed1985

Serotonin-induced vasoconstriction in the perfused canine femoral artery can be blocked in vivo by ketanserin.

Serotonin, applied to helical strips of larger vessels such as coronary arteries, acts as a potent vasoconstrictor in vitro. In contrast, in vivo serotonin causes a remarkable decrease in total peripheral resistance. To differentiate the influence of serotonin on resistances of large and small vessels, experiments were done in nine anesthetized dogs. The left iliacal artery was cannulated and blood flow into the femoral artery was kept constant by a roller pump. Mean proximal femoral artery pressure and mean dorsal pedal artery pressure were measured. Pressure gradient (delta P), resistances between proximal femoral artery and dorsal pedal artery (R1), dorsal pedal artery and right atrium (R2), as well as total peripheral resistance were calculated during systemic infusion of 50 micrograms/kg X min serotonin. Serotonin caused a significant increase in delta P and R1 and a decrease in R2 and total peripheral resistance. Pretreatment with 100 micrograms/kg ketanserin abolished the significant change in delta P and R1, whereas the decrease in R2 and total peripheral resistance was not affected. Additional experiments with prazosin showed that alpha-receptors are obviously not involved in the responses observed. Isosorbide dinitrate, which was infused to differentiate passive and active narrowing of vessels, showed a serotoninlike decrease in mean dorsal pedal artery pressure but no change in either delta P or R1. The 5--HT2-serotonergic antagonist ketanserin blocked serotonin-induced constriction of large vessels in vivo but not the dilation of small arteries.

Animals↗
PubMed1985

Effects of serotonin on the cardiopulmonary circulatory system with and without 5-HT2-receptor blockade by ketanserin.

Pulmonary embolism may cause pulmonary hypertension by mechanical obstruction, which might be amplified by vasoconstriction induced by serotonin released from the emboli. The purpose of the present study was to examine whether 5-HT2-receptors are involved in serotonin-induced pulmonary hypertension. Ketanserin was used as 5-HT2-serotonergic antagonist. In nine anesthetized mongrel dogs, the effect of serotonin infusions (10, 50, 100 micrograms/kg . min) on mean pulmonary artery pressure (PAP), pulmonary vascular resistance (PVR), cardiac output (CO), stroke volume (SV), cardiac contractility (dP/dtmax), heart rate (HR), and mean aortic pressure (PAO) was studied with and without treatment by ketanserin (20 and 100 micrograms/kg). Serotonin caused dose-dependent increase in PAP, PVR, CO, SV, and dP/dtmax. A dose of 20 micrograms/kg ketanserin did not affect hemodynamics significantly, whereas 100 micrograms/kg of the compound significantly reduced PAO, TPR, and left ventricular dP/dtmax. The serotonin-induced increases in PAP, PVR, dP/dtmax, CO, and SV were reduced significantly by 100 micrograms/kg ketanserin; the lower dose of ketanserin had only a slight blocking effect. Ketanserin blocks serotonin-induced pulmonary vasoconstriction partly, but it seems also to antagonize the positive inotropic effect of the monoamine.

Animals↗
PubMed1984

[Suicide and weather].

In 151 patients, admitted to an intensive care unit after attempted suicide, the possible influence of weather at the time of the attempt was analysed retrospectively. The "biosynoptic daily analysis" of the German Weather Service provided the weather data. There was a 5% and 1%, respectively, significant level for the positive correlation between the time of the attempted suicide and the weather parameters "stable upslide, labile upslide, fog and thunderstorm" and the summarized parameters "warm air, upslide and weather drier than on the two preceding days". Significantly fewer attempts than expected occurred when the weather description was "low pressure and trough situation, labile ground layer--upslide above" and the summarized parameters "subsidence or downslide motion". Besides the individual factors such as the reaction to conflicts and the spectrum of reactions, exogenous factors like weather must be considered as important for the time of suicidal attempt.

Adult↗
PubMed1984

Hemodynamic studies on cimetidine and ranitidine in anesthetized dogs.

The cardiovascular effects of the H2-receptor-antagonists cimetidine and ranitidine have been compared in a randomized double-blind crossover study. The experiments were performed in seven anesthetized mongrel dogs. Cimetidine (200 mg) and ranitidine (50 mg) were infused i.v. for 2 min. The time interval between cimetidine and ranitidine application was always 3 h. The direct comparison of the drug effects on blood pressure shows a significant difference between cimetidine and ranitidine (P less than 0.001). Apart from the sequence of application, cimetidine causes a significant decrease (P less than 0.01) in total peripheral resistance (-271 +/- 50 dyn . s . cm-5) resulting in a decrease in mean blood pressure (-9 +/- 1.1 mmHg). In contrast to cimetidine, none of the recorded parameters are altered significantly by ranitidine. Heart rate, left ventricular end-diastolic pressure, myocardial contractility (dP/dtmaxLV), mean right atrial pressure, mean pulmonary artery pressure, and cardiac output are not affected significantly by either drug. Due to our results it might be concluded that the cimetidine-induced hypotension is mediated by peripheral vasodilation.

Animals↗
PubMed1982

Simplifying the intravenous glucose tolerance test.

When used for classifying pregnant patients as normal or abnormal in terms of carbohydrate intolerance, the k value computed from a two-sample intravenous glucose tolerance test (IVGTT) (10 and 60 minutes) is reliable except in a zone of +/- 0.10 k points from the appropriate lower limit of normal. Retesting with six samples obtained in one hour may be required for patients with values within the doubtful range, +/- 0.10 of the lower limit of normal. Considerable savings can be realized nevertheless with the use of this test as compared with doing a full, seven-sample test on each subject. Our results suggest that the abbreviated IVGTT be used more widely as a routine screening procedure for diabetes rather than being restricted to use on suspect populations. One can make a direct conversion of blood sugar readings into k with the use of a table presented in the paper.

Adult↗
PubMed1981

Coronary vasodilation produced by tachycardia under various basal flow conditions.

Some properties of coronary vasodilation produced by heart rate elevation under various basal coronary flow levels was studied. Coronary sinus blood flow, myocardial oxygen consumption and left ventricular contractile force were measured in anaesthetized, open-chest dogs. Heart rate was progressively increased by electrical stimulation at rates ranging from 60/min to 210/min. This was repeated during control, noradrenaline infusion (0.2 microgram kg-1 min-1), in the presence of propranolol (0.25 mg/kg), and during hypopneic positive pressure respiration. It was found that under all experimental conditions, coronary perfusion increased linearly with heart rate. At each rate, coronary flow was greater during noradrenaline infusion and hypopneic respiration than that observed during control or following beta-blockade. Myocardial oxygen consumption behaved similarly to flow, and MVO2 was lowest in the presence of propranolol, and highest during hypopneic ventilation and catecholamine infusion. Contractile force per min (heart rate x tension) also increased with increasing heart rate, but was greatest during noradrenaline infusion, lowest during beta-blockade, and similar during both control and hypopneic respiration. These results indicate that the oxygen cost of contraction was different under the various conditions, and was particularly wasteful during hypopneic respiration. It is concluded that autoregulation caused by heart rate elevation is not dependent on the initial state of coronary blood flow, and that endogenous catecholamine release cannot account for this phenomenon.

Animals↗
PubMed1975

Changes in carbohydrate tolerance during long-term oral contraception.

An intravenous glucose tolerance test (GTT) was given to 116 women--82 nondiabetic subjects (NDS) and 34 diabetes suspects--before they received Ovulen for oral contraception. Subjects were followed for 1 to 4 years during Ovulen therapy. Twenty women using an intrauterine device showed no changes in glucose tolerance. Prompt, significant decline in tolerance was noted in NDS, persisting for the duration of the study. At least one abnormal test, indicating chemical diabetes, was noted in 13 per cent of the NDS. Similarly, prompt decline in tolerance, although not statistically significant, was observed in the suspect group. Fifteen per cent of suspects had at least one abnormal test. Chemical diabetes persisted during Ovulen therapy in suspects but not in NDS. No overt diabetes occurred. Based on greater concern regarding suspects, a procedure for monitoring carbohydrate tolerance is proposed for this group.

Adult↗
PubMed1975

[The influence of feeding on clinical-chemical parameters in the serum of rats (author's transl)].

In the serum of 40 male and 40 female rats the following parameters were determined: Sodium, potassium, creatinine, chloride, calcium, inorganic phosphorus, glucose, urea, protein, cholesterol, bilirubin, lipids, alanine amino-transferase, alkaline phosphatase and leucine arylamidase. The analyses were carried out in the same rats both after continuous feeding, and after a 24-hour fasting periods spaced at intervals of 3- to 4-weeks. The concentration of glucose and the activities of alanine aminotransferase and alkaline phosphatase were higher after feeding than after fasting, and in most cases these differences were statistically significant. The concentration of lipids tended towards increased values. The other parameters examined were slightly or not influenced by the time of the foregoing feeding.

Alanine Transaminase↗
PubMed1975

[Concentrations of amino acids in the blood of different vessels of patients with cirrhosis of the liver during and after the introduction of a porto-caval anastomosis (author's transl)].

In patients with liver cirrhosis the concentrations of amino acids were measured by ion exchange chromatography in the serum of blood samples taken from various vessels during and after the performance of a porto-caval anastomosis. Statistical evaluation was carried out with a nonparametric test. In three female and eight male patients, amino acids were determined intra operationem in blood samples of the following vessels (n = number of blood samples): arm vein (n = 8), arteria femoralis (n =2), vena cava (n = 7), vena portae (n = p) and aorta abdominalis (n = 5). With exception of ornithine (aorta abdominalis versus vena cava), no statistically significant differences in the concentrations of amino acids were observed in the various blood vessels. One to three years after the introduction of the porto-caval shunt, amino acid concentrations were measured in blood from the arm vein and arteria femoralis in four female and five male patients. The concentrations of glutamic acid, phenylalanine and lysine were significantly higher in blood from the arm vein than in blood of the arteria femoralis. The concentrations of valine, leucine and isoleucine were markedly lower in patients with liver cirrhosis than in normal persons. On the basis of the present findings and of the results obtained with normal subjects, it may be concluded that porto-caval anastomosis does not exert a noticeable effect on the metabolism of amino acids in patients with liver cirrhosis.

Adult↗
PubMed1975

[Determination of clinical chemical parameters in laboratory animals. Report of the workshop conference of the German Society for Clinical Chemistry held in Bad König/Odenwald, Germany, on the 11th and 12th of October 1974 (author's transl)].

Clinical chemical analyses are carried out in many animal experiments performed for medicinal research. For the evaluation of the analytical results fundamentals which have been tried tested and proven in human medicine are still frequently missing, such as reliability criteria, reference values, condition of specimen collecting and the knowledge of other important influences. The workshop conference of the German Society for Clinical Chemistry therefore prepared an inventory, and the most important problems were discussed with examples; guide-lines were worked out for planning, performance and evaluation of clinical chemical investigations on laboratory animals.

Age Factors↗
PubMed1975

[Enzyme-activities in serum and plasma of man, dog and rat, and the variation of these enzyme activities during storage of the blood].

The following enzymes were determined in the serum and plasma of man, dog and rat: alanine aminotransferase, asparate aminotransferase, alkaline phosphatase, lactate dehydrogenase and alpha-hydroxybutyrate dehydrogenase. The enzyme assays were performed on an Eppendorf-Enzymautomat 5010 using optimised conditions at 25 degrees C. The enzyme-activities changed by variable amounts during standing of the blood. This concerned mainly lactate dehydrogenase, alpha-hydroxybutyrate dehydrogenase and aspartate aminotransferase in the serum of the rat. In human serum and in dog serum, and in the plasma of man, dog and rat this effect was only less pronounced.

Adult↗