Digitoxin antagonism by visnadin

Visnadin, a lactone derived from bishop's weed, has been found to have marked antidotal properties in animals poisoned with digitoxin. It increases survival on acute and chronic administration of the glycoside, prevents the appearance of bradycardia, and reverses cardiac arrhythmias. Copyright © 1962 Wiley‐Liss, Inc., A Wiley Compan

Hydroxyproline excretion in pituitary dwarfs treated with therapeutic doses of human growth hormone

Hydroxyproline excretion in the urine was measured in five pituitary dwarfs during a 4-month period of treatment with 10 IU/week of growth hormone and during 4 months following treatment, in order to assess its value as an index of therapeutic response. The excretion of hydroxyproline was found to be within normal limits (26–57 mg/24 h/m2) on control days, and this excretion presented a gradual increase in the last 2 months of treatment; this was, however, not of statistical significance. After cessation of treatment, hydroxyproline levels returned to pretreatment values. The clinical effect was significant in all patients, who gained 2–5 cm within the 4 months of treatment, as compared to an anual increase of 1–3 cm during the pretreatment year. The above results suggest that hydroxyproline excretion cannot be considered as a reliable parameter of the therapeutic response of pituitary dwarfs to chronic growth hormone treatment with the established doses. © 1973 S. Karger AG, Basel

The effect of sumatriptan on brain monoamines in rats

Clinical data suggests that sumatriptan is effective in the acute treatment of migraine. The vascular effects of the drug have been invoked to explain this antimigraine efficacy. However, the effect of sumatriptan on brain monoamines has not previously been investigated. In order to study these hypothetical effects, we administered the drug to 24 male rats, subcutaneously, at three doses (0.3, 0.6, and 0.9 mg/kg of body weight), and 30 minutes later, all animals were decapitated. Dopamine, serotonin, and their metabolites 3,4 dihydroxyphenylacetic acid, 5-hydroxyindoleacetic acid, and homovanillic acid concentrations were measured in the frontal cortex, hypothalamus, striatum, and hippocampus, by high performance liquid chromatography. Plasma concentrations of the drug were also determined. The control group was treated with NaCl 0.9%, given subcutaneously. Sumatriptan, at the dose of 0.3 mg/kg did not alter the brain monoamine concentrations; however, at the dose of 0.6 mg/kg, sumatriptan decreased serotonin concentration in the hypothalamus and increased the turnover of dopamine and serotonin in the hypothalamus and striatum, while at the dose of 0.9 mg/kg, it augmented only the turnover of serotonin in the hypothalamus. No dose- dependent effect of the drug was found. This subcortical antidopaminergic end antiserotoninergic effect of sumatriptan may be involved in its antimigraine action

Behavioural and biochemical effects of haloperidol during the oestrous cycle of the rat

The effects of two doses (1 and 2 mg/kg, i.p.) of haloperidol (HAL) on catalepsy, on concentrations of DA and DOPAC in frontal cortex, nucleus accumbens and striatum and on serum levels of oestradiol were investigated in intact female rats during the 4-day oestrous cycle. Catalepsy induced by haloperidol did not vary much during phases of the cycle. The turnover of DA in the cortex induced by haloperidol was significantly greater on proestrus and smaller on oestrus. The effect of haloperidol on the turnover of DA in the nucleus accumbens and in striatum was marginally affected by the oestrous cycle being greatest on oestrus. The levels of serum oestradiol were higher on proestrus and lower on oestrus. No significant differences were detected between diestrus and metestrus. After haloperidol there was a dramatic increase in serum oestradiol on oestrus, a slight increase on metestrus and diestrus and a decrease on proestrus. However, serum levels of oestradiol were not significantly different between phases of the cycle in rats treated with haloperidol. The results indicate that the oestrous cycle has a detectable influence on DAergic mechanisms in the frontal cortex and possibly in the tuberoinfudibular system, brought about by treatment with haloperidol. © 1988

A cross-national comparison of cognitive conflict

The results of 5 “lens model” interpersonal conflict (IPC) experiments, carried out in 5 countries: Czechoslovakia, Greece, Japan, Sweden and the U. S. were compared. Replicating earlier intranational findings, conflict reduction was found to be very slow. Although the subjects reduced the differences between their policies to a considerable extent, the consistency of their policies was also reduced, preventing the subjects from deriving the full benefits of the reduction of the policy differences, and leaving conflict at a high level. No reliable cross-national differences were found. In addition, it was shown that the differences found between American and European subjects in an earlier study were due to procedural differences between the American and European experiments in that study. It was concluded that the phenomena studied in the “lens model” IPC experiments are independent of cultural factors, and reflect limitations in the human information processing system. © 1970, Sage Publications. All rights reserved

Does stress influence ampicillin concentration in serum and tissues?

Exercise produces changes of drug levels in plasma and increases the concentration of free fatty acids (FFAs), which may interfere with drug-protein binding. FFAs seem to play an antagonistic role to drugs since they have a strong binding capacity to serum albumin. The aim of this study was to evaluate the influence of the consecutive exercise-induced stress in ampicillin levels. Two groups of Wistar rats were used. Group A consisted of six subgroups that were subjected to cold swimming (4°C) for 5, 10, 15, 20, 25, 30 days respectively. Group B was the control group. The animals were injected im. with ampicillin (1 g/Kg/8h in 5 doses). Results showed that exercise enhanced stress parameters (FFAs, adrenal weight, Ht%) and led to an ampicillin increase in all experimental groups comparatively to controls

Canine capillary formation in vitro

Microvascular endothelial cells derived from canine subcutaneous adipose tissue formed knob-like and tube-like structures in vitro without tumorconditioned medium or special substrate. The knob-like structures consisted of acidic and basic glycosaminoglycans arranged in order. Knob-like structures were built from cell extrudates and were responsible for capillary lumen formation in vitro. Transmission electron microscopy confirmed the endothelial nature of the cells which expressed extensive phagolysosomal activity