[Thiophosphamide induction of sister chromatid exchanges at various phases in the cell cycle of a Chinese hamster cell culture].

Influence of three concentrations of thiophosphamide (thioTEPA) on the formation of sister chromatid exchanges (SCE) has been studied at different phases during 2 cell cycles in cultured Chinese hamster cells. It is shown that the frequency of SCE does not differ from the control level under the effect of the mutagen on cells in the G2 phase of the first cell cycle from the moment of harvesting. Thiophosphamide induces the same number of SCE at S, G1 stages of the first cell cycle and G2 of the second one till the moment of harvesting. The number of SCE correlates in a direct proportion with a concentration of thiophosphamide. A scheme of forming SCE is proposed.