[Induction of cytogenetic damage in Chinese hamster cells after combined exposure to low doses of gamma-radiation and various chemical and physical agents].

Supersensitivity of Chinese hamster cells to low doses of gamma-radiation (dose range 5 to 50 cGy) was revealed by means of the cytokinesis-block micronucleus test. Treating these cells with caffeine (repair inhibitor) and mercaptoethylamine (radioprotector) and exposing them to secondary radiation emitted by protons with an energy of 70 GeV showed that this supersensitivity is associated with the absence of cytogenetic repair. When cells at the G2 phase received preliminary doses of 30 and 75 cGy before being irradiated at 150 cGy, the incidence of cytogenetic damage decreased, i.e., an adaptive cell response resulting from a radiation-induced mitotic delay was observed.