Biomedical subjects
Publications and source records attributed to M Winter.
The human gastric mucosa generates prostacyclin (22 +/- 6 ng PG I2/g). There is no age or sex difference in PG I2 formation by normal gastric mucosa. The properties of the substance are the same as reported in other tissues.
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The newly formed tissue of dacron vascular prosthetic grafts implanted in humans demonstrates prostacyclin generation and fibrinolytic activity comparable to that of the atherosclerotic artery in the vicinity. This provides some evidence that both activities important for haemostasis run parallel.
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The absorption and biliary excretion of drotaverin/a papaverine analogue/were studied in rats. In vivo loop technique was used. The absorption of the compounds from the jejunum was found to be rapid and the activity injected into the duodenal sac to disappear only when the common bile duct was ligated. An appreciable activity was detected in the bile collected by cannulation following both i.v. (67%) or per os (31%) administration. Considerable activity was excreted with the bile even 24 hours after drug administration. A partial entero-hepatic cycle for the drotaverin metabolites is suggested.
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Activated smooth muscle cells exhibit a statistically significant (p less than 0.025) higher prostacyclin production than the contractiles. It is concluded, that the proliferation of the metabolically activated cells, which is an early event in atherogenesis, could be due to prostacyclin regulation.
Quantitative changes in the internal elastic membrane (IEM) were studied in human arteries from different location in 31 males and 31 females, using an eight-criterion classification system. The IEM involvement shows a sex-dependent increase with age, and is more pronounced in arteries known to exhibit a more intensive atherosclerotic involvement. It seems that the IEM changes represent a true ageing phenomenon, which is sometimes influenced to a various degree by the atherosclerotic process.
Prostacyclin (PGx, PG12) activity can be found in renal tissue as indicated by platelet aggregation inhibition. The activity of the medullary tissue in terms of wet weight is significantly higher (P less than 0.01) than that of cortex. The activity decreases with time and has almost entirely gone within 1 h. Boiling for 30 s destroys the inhibitory effect of the prostacyclin on platelet aggregation. Angiotensin II is able to stimulate the prostacyclin availability of the tissue after incubation for 3 min. Addition of angiotensin II to platelet-rich plasma (PRP) has no significant effect on ADP-induced platelet aggregation. The spontaneous generation of prostacyclin as well as that stimulated by angiotensin II can be suppressed by previous incubation of the tissue with a prostaglandin synthetase inhibitor such as ketoprofen. Tissues which have only a small amount of basal release in buffer show an increased platelet aggregation inhibitory effect after addition to PRP. The difference between medulla and cortex is statistically significant. This different release of prostacyclin cannot be related to different endothelial surface area, because the endothelial surface in medulla and cortex is quite similar. It is suggested that prostacyclin has an important influence on the renal function. The different capacity of renal medulla and cortex in generation of prostacyclin could be of great importance for a fuller understanding of the physiology of renal function.
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In 1076 sera of healthy volunteer blood donors from Vienna and surroundings HBSAg was positive in 1,7%, HBSAb in 9,5%, HBCAb in 5,7% by radioimmunoassays. HA-Ab was more frequently positive in the rural than in the urban population, its incidence was higher than it was observed by others in Switzerland and in the USA, but lower than in Belgium, Israel, Yugoslavia and Taiwan. 4% of the blood units were positive for HBCAb but negative for HBSAg. The possibility to decrease the incidence of posttransfusion hepatitis by screening for HBCAb is discussed.
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Morphological control of Moncada's bioassay for prostacyclin (PG I2) activity measurement shows that the activity depends not only on endothelium, but in important amounts on subendothelial tissue too. Therefore, it can be concluded that platelet thrombus formation after endothelial cell injury does not depend only on the PG I2-producing ability of the tissue.
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Twenty skin-presensitised Lewis rats received kidney transplants from (Lewis X BN)f1 rats. Two grafts each were withdrawn at intervals from 1--120 min and examined using a scanning electron microscopic (SEM). A series of Lewis to Lewis isografts served as control. In hyperacute rejection at just 1 min spider-like fibrin fibres and platelets could be observed in small arteries, where the endothelium was severely altered. In these regions at 2 and particularly 5 min a fibrin network often contained platelet aggregates, mechanically altered erythrocytes as well as different kinds of leucocytes. This coagulation process progressed with time and resulted in a complete vascular occlusion at 30--60 min.