[Post-irradiation modification of radiation damage to cells. Increase in reproductive death during post-irradiation reduction of cellular pH].

The effect of enhancement of reproductive death in postradiation reduction of intracellular pH(pHk) was studied on Chinese hamster hypoxic cells. It was shown that pHk reduction up to 6.0 for 1 h enhanced the radiation damaging effect. The maximum effect was observed in pHk reduction shortly after irradiation. The dependence of the effect on the interval between irradiation and subsequent pHk reduction was different under various conditions of postradiation incubation: in good oxygenation due to fast reparation of potential injuries the effect of pHk reduction sharply decreased with time; the effect of additional influence of pHk reduction was insignificant against a background of low survival of cells incubated after radiation under hypoxic conditions. It was assumed that low survival under postradiation hypoxic conditions was determined by pHk reduction shown in this study during cell incubation under hypoxic conditions.