[Residual DNA damages in irradiated HeLa cells]

A possibility to detect the low level residual DNA damages was undertaken in HeLa cells during a long time after irradiation. The mixture of two inhibitors of replicative and reparative syntheses (hydroxyurea and beta-arabinosylcytosine) was added to the HeLa monolayer culture cells 6--24 hours after irradiation, when the potentially lethal damages was removed. A decrease in cell survival was shown. These data suggest that a certain amount of damages may still remain in DNA of irradiated cells.