Figure 1.

The effect of low-dose ionizing radiation on postnatal growth. (A) Photograph of 10-day-old wild-type and Ku80^−/− littermates. Wild-type and Ku80^−/− mice were irradiated within 24 hr of birth by using a ¹³⁷Cs source with a rate of 83 cGy. Unirradiated Ku80^−/− mouse is shown for comparison. There is no difference in size between irradiated and unirradiated wild-type mice (not shown). (B) Postnatal growth of one wild-type and three Ku80^−/− male littermates, two of which were treated with 100 cGy irradiation. Weights of individual animals (wild-type mice, •; irradiated Ku80^−/− mice, □; and untreated Ku80^−/− mice, ▪) are plotted against time. Irradiated Ku80^−/− mice subsequently died 16 days and 30 days postirradiation as indicated. (C) The effect of 50-cGy irradiation on the growth of Ku80^−/− mice. Growth of female wild-type, irradiated, and untreated Ku80^−/− mice are shown. Data are representative of five independent experiments.