The effect of taurine on the activity of transport ATPases and of energy metabolism enzymes in different tissues of rats with acute hypoxic hypoxia]

The membrane activity of Na+, K(+)-ATPase, Mg2+, Ca(2+)-ATPase, mitochondrial NAD-isocitrate dehydrogenase, mitochondrial and cytosolic L-glycerol-3-phosphate dehydrogenase was determined in the liver and brain of Wistar rats under acute hypoxic hypoxia against the background of preventive taurine administration. It was shown that preliminary taurine treatment prevented a decrease of hypoxia in activity of Na+. K(+)-ATPase and mitochondrial calcium-dependent enzymes, mostly in the liver. Changes in the intracellular calcium content and biomembrane structure have been discussed as the mechanisms of the taurine effect on the enzymes' activity.     

Biological activities of human interferon and 2′–5′ oligoadenylates in plants

Exogenous human interferon 2 (IFN) and 2–5 oligoadenylates (2–5A) have been shown to cause at least a dual physiological effect in tobacco and wheat: (i) increased cytokinin activity and (ii) induced synthesis of numerous proteins, among which members of two groups of stress proteins have been identified, namely pathogenesis-related (PR) and heat shock (HS) proteins. These effects were observed only by low concentrations of these substances: IFN at 0.1–1 u/ml and 2–5A at 1–10 nM.     

Accumulation in the regenerating liver of hepatocytes with pathological nuclei as affected by daunorubicin

The action of the antitumor antibiotic rubomycin on dividing cells in the regenerating liver was studied. The antibiotic was administered 2 hours before partial hepatectomy in single doses of 1 to 8 mg/kg. It was shown that any of these doses provided equal suppression of the cell division. Mitosis always started on the 5th or 6th day. Various forms of mitosis pathology were observed. On the 7th day after the partial hepatectomy there was detected a large number of pathologically changed nuclei in the liver. With an increase in the rubomycin dose their number increased. With an increase in the dose there was also observed a large number of affections associated with impairment of the mitotic apparatus. After some time the morphologically visible nuclear disorders in the population disappeared. In six months there were practically no pathological nuclei in the liver. Three aspects of the antibiotic action i.e. toxic action, cytostatic action and induction of chromosomal aberrations are discussed. The toxic action and induction of chromosomal aberrations increased with increasing the drug dose while the cytotoxic action did not change.     

Formation of complexes of ascorbic acid and biological ligands

Ascorbic acid has wide usage in medical practice for treatment some diseases caused by degeneration of connective tissue. Ascorbic acid has strong reduce properties. This article is dedicated to investigating complexation properties of ascorbic acid with components of biomembrans-bioligands: the most widespread aminoacids of connective tissue, phosphatidylholine, ATP, calcium salts, proteins. The investigations realised give the opportunity to make the conclusion that ascorbic acid has some complexation properties with different bioligands. But the stability of these complex products is different. And these stability variationes are described in this article.     

Effect of L-arginine on Na+,K+-ATPase activity in rat aorta endothelium

The effect of L-arginine on the Na⁺,K⁺-ATPase activity in rat aorta endothelium was studied at its physiological concentrations in the range of 10^–6-10^–3 M. The enzyme activity was 35.5% increased by low concentrations of L-arginine (10^–5 M) and its activity was 32.3-37.1% decreased at the L-arginine concentrations of 10^–4-10^–3 M. A similar inhibition (by 34.5-42.8%) was also found in the presence of a NO-donor nitroglycerol (10^–4-10^–3 M). An optical isomer of L-arginine, D-arginine, at the concentrations of 10^–5 M also increased the enzyme activity by 37.1%, but its inhibiting effect was much less pronounced and was 15.7% at the D-arginine concentration of 10^–3 M. An inhibitor of NO-synthase, L-NAME (N^G-nitroarginine, methyl ester), failed to inhibit Na⁺,K⁺-ATPase. However, the presence of L-NAME abolished the inhibition of Na⁺,K⁺-ATPase by high concentrations of L-arginine. Thus, the effect of L-arginine on the endothelial Na⁺-pump depended on its concentration, and it is suggested that the enzyme inhibition by high concentrations of L-arginine should be associated with activation of the endogenous synthesis of NO.