[Effect of irradiation on the degradation of rat thymocyte chromatin]. / Vplyv ionizuiuchoï radiatsiï na dehradatsiiu khromatynu tymotsytiv shchuriv.

Genome instability of adaptive nature is formed under the experimental influence on a cell. Under critical conditions, strategy of organism is to damage the cells that cannot be restored and controlled by including the program of apoptosis. The ordered internucleosomal DNA degradation is considered to be one of the proof attributes of immunocompetent cell apoptosis. We investigated the effects of various doses of irradiation on the thymocytes chromatine fragmentation in 1,2,3 hours after a single X-ray exposure or after chronic influence in conditions of Chernobyl research base. By the means of electrophoresis in agarose and judging by polydeoxyribonucleotides accumulation we observed the "ladder pattern" of degradation in 3 hr after single 1 Gr irradiation (the smallest dose displaying the effect). We suppose that the influence of both chronic low-intensity irradiation taking place in Chernobyl and single X-ray exposure result in intensifying of DNA fragmentation in the cells of immunocompetent organs.

[Determination of DNA damage in nonproliferating animal cells]. / Opredelenie povrezhdenii DNK v neproliferiruiushchikh kletkakh zhivotnykh.

The modification of precipitation method for detecting DNA damage in mammalian cells using fluorimetric assay with 3.5-diaminobenzoic acid has been suggested. This modification allows determining DNA single- and double-strand breaks in mammalian nonproliferating cells and tissues. The influence of ionizing radiation upon the DNA damage in lymphoid cells of rat's spleen and thymus has been studied.

[Second messenger systems and protein kinase activity in rat thymus and liver in the early stages of radiation injury]. / Sistemy vtorichnykh messendzherov i aktivnost' proteinkinaz v timuse i pecheni krys na rannikh étapakh luchevogo porazheniia.

The effect of ionizing radiation (7, 76 Gr) on the content of cyclic nucleotides and Ca2+ ions from rat thymus and liver has been established: it was increased 15, 30 min and 4.6 h and decreased 2, 12 h and 24 h after the irradiation. Changes in activity of cyclic nucleotide-dependent protein kinases and Ca2+, phospholipid-dependent protein kinase correlated with the contents of secondary messengers in the irradiated rats (30 min and 4 h after irradiation) are shown.