Proliferation Characteristics of Cultured Mammalian Cells after Irradiation with Sparsely and Densely Ionizing Radiations

Abstract

SummaryClone size distributions of mammalian cells cultured by Puck's technique have been determined after irradiation with various single doses of 250 kvp x-rays and 3.2 mev α-radiation. The distributions broadened progressively with increasing doses of either of the two types of radiations. No qualitative differences were observed between the actions of the two radiations.In addition proliferation kinetics were studied of microclones, which 15 days after irradiation with x- or α-radiation, corresponding to 14 doubling times of clones developed from unirradiated cells, contained less than 50 cells. Some of these microclones decreased with respect to their number of cells and finally disappeared. However, other microclones slowly increased in cell number and had retained the capacity for unlimited proliferation. Nevertheless, these macroclones which had developed from microclones show many unsuccessful mitoses even after a large number of divisions. No differences were observed in the characteristics of this non-lethal damage produced by 250 kvp x-rays and 3·2 mev α-radiation.