Biomedical subjects
Publications and source records attributed to R Tarnawski.
NMR investigations of model protein of elastic fibre is presented. Detailed conformation of alpha-elastin polypeptide chain is discussed by comparison with the conformation of synthetic repeat peptides of elastin. Amino acid composition of alpha-elastin obtained from C-13 NMR spectra correlates with the results of sequencing of tropoelastin.
The authors present effect of the end to side portacaval shunt (E-S PCS) and side to side portacaval shunt (S-S PCS) on monoamine oxidase (MAO) activity in brain cortex and cerebellum of rats. There were significant differences between two experimental models of PCS. Our results show greater increase in MAO activity after end to side portacaval shunt.
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Aspartate carbamoyltransferase (ACTase) activity has been measured in rat livers at different stages of their development and in intact and regenerating livers. The level of enzyme activity was found to be the highest in the earliest fetal livers (about 7 times higher than in the adult rat liver). Deproteinized by heating, supernatants of sheep liver homogenates were purified on a Sephadex G-25 column. The influence of deproteinized supernatant on ACTase activity in rat liver was measured. This influence depended on the amount of activating factor added to fresh homogenates. A different scope of activation of enzyme activity in rat liver caused by deproteinized supernatant was noticed. The greatest increase of enzyme activity under the influence of activating factor was obtained in the liver of young animals, mothers and old female rats, the smallest in fetuses and very young animals. A relatively smaller increase of enzyme activity was observed in regenerating livers under the same experimental conditions. In this article the role of natural ACTase activator is discussed.
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Methylglyoxal in doses over 25 mg/kg injected intravenously in cats and rabbits produces distinct changes in the cardiovascular and respiratory systems, but has no effect on respiration or circulation when injected intraperitoneally even in doses up to 1 g/kg. The effect of MG on blood pressure depends on the species of the animal. The effects of MG are dose-related and dependent on the route of its administration. Biochemical studies showed a significant rise in serum activities of creatine kinase (EC 2-7-3-2), lactate dehydrogenase (EC 1-1-1-27) and aspartate aminotransferase (EC 2-6-1-1-) after intraperitoneal injection of MG in the dose of 200 mg/kg in rabbits and 500 mg/kg in rats. The observed changes probably indicate damage of muscle tissue by MG, presumably as a result of low content of one of the glyoxalases in the muscles of the experimental animals. Elevation of glucose levels by MG was probably an adrenergic effect. These biochemical changes can serve to evaluate toxicity of MG preparations, which exhibit variations probably owing to varying degree of polymerization.
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INTRODUCTION: The aim of study was to assess the relation between plasma level of one of the oxysterols--7-ketocholesterol and angiographically evidenced coronary artery disease. MATERIAL AND METHODS: We measured plasma level of 7-ketocholesterol, malondialdehyde, total cholesterol, HDL cholesterol, triglycerides, erythrocyte activity of superoxide dismutase in 233 patients who previously underwent coronary angiography for diagnosis of coronary artery disease. The follow-up of patients (28 months) was done on basis of questionnaires sent out to them. RESULTS: We found that the subgroup of patients with 7-ketocholesterol above the median value (62 ng/mL) has higher rate of coronary reintervention (8/54 pts vs. 5/43 pts in 7-ketocholesterol below 62 ng/mL respectively, p = 0.284 Log-rank test). The finding was more pronounced, yet insignificant, in the subgroup of patients who underwent primary PTCA (6/19 pts vs. 2/20 pts, p = 0.1 Log-rank test). There were 3 patients in high 7-ketocholesterol subgroup who entered the study with previously undergone primary coronary intervention. There were not such patients in low 7-ketocholesterol subgroup. 4 deaths were observed in high 7-ketocholesterol subgroup, and one in low 7-ketocholesterol subgroup (they were predominantly not of cardiovascular origin). CONCLUSIONS: We failed to find a significant relation between 7-ketocholesterol and coronary artery disease, though there is a trend of such relation in patients who undergo PTCA, evidenced by a slightly higher number of repeated revascularizations among patients with high 7-ketocholesterol. The study indicates the areas of further studies with agents capable of lowering oxysterols and assessing also other end points.
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