[Antioxidative protection in the central nervous ganglia of a mollusc Lymnaea stagnalis at modulation of activity of the NO-ergic system].

In experiments on molluscs Lymnnaea stagnalis the state of antioxidative protection is studied in central nervous ganglia during a long-term activation (inhibition) of synthesis of nitric monoxide (NO) in the body. Effect of the blocker of NO-synthase N(G)-nitro-L-arginine (L-NNA) at the background of enhancement of pulmonary respiration has been established to be associated with a rise of levels of reduced glutathione and TBK-active products in the nervous tissue at preservation of a relatively high superoxide dismutase activity and a low glutathione peroxidase activity as compared with control group and the animals treated with the metabolic precursor of NO synthesis L-arginine. In spite of the revealed disturbances of balance of the body pro- and antioxidative system, DNA electrophoresis detected no products of its degradation, which can indicate the absence of massive programmed death of the nervous tissue cells in Lymnaea stagnalis during modulation of activity of the NO-ergic system.

Protective effect of natural flavonoids on rat peritoneal macrophages injury caused by asbestos fibers.

Exposure of macrophages to asbestos fibers resulted in enhancement of the production of oxygen radicals, determined by a lucigenin enhanced chemiluminescence (LEC) assay, a formation of thiobarbituric acid reactive substances (TBARS), a LDH release into the incubation mixture, and a rapid lysis of the cells. Rutin (Rut) and quercetin (Qr) were effective in inhibiting LEC, TBARS formation, and reducing peritoneal macrophages injury caused by asbestos. The concentrations pre-treatment of antioxidants that were required to prevent the injury of peritoneal macrophages caused by asbestos by 50% (IC50) were 90 microM and 290 microM for Qr and Rut, respectively. Both flavonoids were found to be oxidized during exposure of peritoneal macrophages to asbestos and the oxidation was SOD sensitive. The efficacy of flavonoids as antioxidant agents as well as superoxide ion scavengers was also evaluated using appropriate model systems, and both quercetin and rutin were found to be effective in scavenging O2.-. These findings indicate that flavonoids are able to prevent the respiratory burst in rat peritoneal macrophages exposed to asbestos at the stage of activated oxygen species generation, mainly as superoxide scavengers. On the basis of this study it was concluded that natural flavonoids quercetin and rutin would be promising drug candidates for a prophylactic asbestos-induced disease.

[Status of the antioxidant protective system of rat liver exposed to carbon tetrachloride]. / Sostoianie antiokislitel'noi zashchitnoi sistemy pecheni krys pri vozdeistvii chetyrekhkhloristogo ugleroda.

The dynamics of enzyme activity of antioxidative protective system of the liver and the content of restored glutathione have been studied in rats poisoned by CCl4 injection. During the first hours followed the injection against the background of maximum accumulation of dienic conjugates and decrease of the restored glutathione level no significant changes in the enzyme activity of the antioxidative protective liver system were observed. At the same time 48 hours later the superoxide dismutase and catalase activity decreased by 38% and 36%, respectively, with relative stability of glutathione-dependent enzymes and a two-fold increase of the restored glutathione level. It is shown that a fall of activity of the cytoplasmic antioxidative liver enzymes is not a result of the immediate inactivating effect of free-radical reactions initiated by CCl4, but is, evidently, caused by the covalent binding of its radical metabolites with corresponding macromolecules.

[Efficacy of various antioxidants in experimental ischemia and myocardial infarct in the rat]. / Effektivnost' nekotorykh antioksidantov pri éksperimental'nykh ishemii i infarkte miokarda u krys.

Complex of vitamins E and C showed the most effective antinecrotic action in rats with simulated myocardial infarction in series of antioxidants studied: ascorbate, alpha-tocopherol, quercetine, derivatives of o-benzoquinone OBQ2 and OBQ3. Stabilization of lipid peroxidation in cardiomyocytes, increase in biomembranes stability and absence of distinct alterations in the antioxidative enzymatic system were found in rats with ischemia and myocardial infarction after treatment with the complex. Protective effect of the vitamins E and C complex was realised via antiradical mechanism.

[Effect of antioxidants on the status of the antioxidative system in cerebral ischemia and reperfusion injury]. / Vliianie antioksidantov na sostoianie antiokislitel'noi sistemy v usloviiakh ishemicheskikh i reperfuzionnykh povrezhdenii golovnogo mozga.

Protective effects of ionol, o-benzoquinone-2 and ascorbic acid, their influence on the activity of antioxidative enzymes, the level of diene conjugates (DC) and of recovered glutathione in the mitochondrial fraction in the case of ischemic and reperfusion injury of the brain have been investigated. An increase in the activity of the antioxidative system enzymes during the post-ischemic period induced probably by the accumulated products of lipid peroxidation is shown: glutathione peroxidase (EC 1.11.1.9)--by 159%, glutathione reductase (EC 1.6.4.2)--by 26%, catalase (EC 1.11.1.6)--by 79%. This effect was not observed after introduction of antioxidants lowering the DC-level. It is concluded that antihypoxic action of the investigated antioxidants providing the survival of animals not only after the 5 min total circulatory ischemia but also after the 15 min one is caused by their antiradical properties and is not connected with stimulation of activity of enzymes supporting peroxidative homeostasis.

[Quinone-reducing activity of thrombocytes]. / Khinonredutsiruiushchaia aktivnost' trombotsitov.

NAD/P/H: quinone-oxidoreductase activity was determined in human thrombocytes using spectrophotometric and polarographic methods. Detergents, vitamins K3 and K1, ADP-induced aggregation of the thrombocytes were shown to affect the thrombocytic guinone-reductase activity. Possible localization of quinone-reductase in thrombocytes and its importance for the state of thrombocytic membrane are discussed.