[On the mechanism of radioprotective effect of NO-synthase inhibitors].

We studied the influence on hemodynamics and radioprotective activity of two inhibitors of NO-synthase (NOS)--isothiourea derivatives with different NOS isoform selectivity: T1023--a selective inhibitor of endothelial and inducible NOS; and NTT2--a highly selective inhibitor of neuronal NOS. Both compounds at a dose of 1/7 LD50/15 caused a vasopressive effect and baroreflex response in normal Wistar rats. However, the nature of hemodynamic changes was qualitatively different.

[Radioprotective properties of isothiourea derivatives with NO-inhibitory mechanism of action].

The study of the radioprotective activity of S-[2-alkyl (aryl) sulfonyl]-S-ethyl derivatives of (vinyl)-isothiourea in (he model of the survival of mice exposed to gamma-radiation at a dose of 10 Gy has shown that the incorporation of additional sulfur-containing groups does not increase the radioprotective properties of compounds. In contrast to aminoalkil thiols, the effectiveness of the radiation protection action of the isothiourea (ITU) derivatives studied clearly correlates with the NO-inhibitory activity. This fact allowed us to assume that the radioprotective effect of S-substituted ITU caused inhibition of the endogenous synthesis of NO, which promotes the development of circulatory hypoxia, and that a further search for the radioprotective agents in this class of chemicals should be considered as the search for effective inhibitors of NO-synthase (NOS).

Evaluation of psychoemotional status of rats after brain injury and systemic transplantation of mesenchymal stem cells.

We studied the effects of systemic transplantation of mesenchymal stem cells obtained after culturing of autologous bone marrow on psychophysiological status of Wistar rats after diffuse brain trauma. Two months after systemic injection of mesenchymal stem cells we observed a decrease in manifestations of emotional behavioral reactions (anxiety and excitability) and shortening of the time of realization of drinking behavior in a T-maze. A significant positive effect of systemic transfusion of mesenchymal stem cells on avoidance conditioning in a shuttle box was observed 3 months after brain injury.

[Toxicity and side effects of antibiotics in radiation sickness and during the use of aminothiol group radioprotective agents].

It was shown in experiments on mice, rats and rabbits that resistance of animals in the state of acute radiation sickness to severe intoxication by aminoglycoside antibiotics, such as streptomycin, dihydrostreptomycin and monomycin did not significantly change. The exception was kanamycin the toxicity of which during the period of the acute state of radiation sickness increased by 30 per cent. The use of cystamine and merkamine before irradiation or their administration to non-irradiated animals resulted in lowering of the antibiotic tolerance by 1.