THE EFFECTS OF GAMMA IRRADIATION OF HUMAN FIBROBLASTS ON HUMAN/CHINESE HAMSTER SOMATIC CELL HYBRIDS
Human fibroblast cells were exposed to 0, 10, 20, or 40 Grays of gamma rays and then fused with unirradiated Chinese hamster cells deficient in HPRT. THAG selection system was used to ensure that only hybrid cell lines could survive. The time of appearance of pickable hybrid colonies and the frequency of dishes without any colonies were related to radiation dose. As the radiation dose increased, there was a positive correlation with frequency of cells with abnormal nuclei and a negative correlation with frequency of human chromosomes. Additionally, the hamster chromosomes had damage similar to that produced by radiation; the frequency of damaged hamster chromosomes was positively correlated with radiation dose.