[Effect of protein kinase C and NO-synthase inhibitors on the radiation-induced cytogenetic adaptive response in cultured Chinese hamster cells].

The effects of the serin-threonin kinase inhibitor--staurosporin and inhibitor of NO-synthase--L-NAME on the radiation-induced adaptive response were studied in fibroblasts of Chinese hamster in culture. We have shown that the adaptive response as measured by the reduction of radiation-induced chromosome aberrations was completely blocked in the presence of staurosporin as well as L-NAME. These inhibitors themselves did not increase the chromosome aberration frequency when cultures were irradiated with 3 Gy alone in the presence of inhibitors.

[Study of the radioprotective effect of the NO-synthase inhibitor L-NAME in Chinese hamster cell culture].

A radioprotective effect of L-NAME was estimated by the yield of the aberrant anaphases after exposure of Chinese hamster cells to different doses of gamma-rays and beta-particles. It was shown that cell treatment with L-NAME before irradiation only decreased the frequency of radiation-induced chromosome aberrations. The equal yield of the aberrant anaphases was found in the cells treated with L-NAME and irradiated with 6 Gy gamma-rays later and in the cells non-treated with L-NAME and irradiated with 3 Gy gamma-rays.

[Cellular reactions induced by chronic exposure to 14C beta-rays].

In V-79 cells the Effects of chronic exposure on induction of chromosome aberrations and abnormal metaphases as well as on efficiency of subsequent exposure to 2 Gy gamma-rays were investigated. It was found that chronic exposure increased the yield of chromosome aberrations as well as abnormal metaphases (spread-metaphases and apoptotic metaphases). In spite of the level of damages in cells, the chronic beta-exposure protected cells against the additional induction of chromosomal aberrations by subsequent exposure to higher acute dose of gamma-irradiation.

[Characterization of the adaptive response to the action of gamma-rays, induced by low doses of 14C in Chinese hamster fibroblasts].

It has been studied the correlation of the mitotic activity of the chromosome aberrations and apoptosis, in the V-79 cells pre-exposure to an adapting dose of ionizing radiation from 14C-thymidine prior to an acute challenge dose of gamma-rays. In spite of that the incubation of the cells with isotope increased of the yield of the chromosome aberrations, but the cells became more resistant to following gamma-irradiation. Increasing the adaptive dose of the 14C on degree didn't influence on the present of the adaptive response.