Fig. 7.
Effect of minimal irradiation on stem cells irradiated in vivo or in vitro. Male marrow cells from BALB/c male mice were exposed to irradiation (0, 20, 50, 70, 100, and 200 cGy) in vitro and 40 × 106 was immediately infused into female recipients irradiated with 100 cGy. In another experiment, BALB/c male mice in groups of 5 were exposed to irradiation (0, 20, 50, 70, and 100 cGy), marrow cells were harvested, and 40 × 106 male marrow cells were immediately infused into female recipients irradiated with 100 cGy (groups of 5). At 2 months, the percentage of male engraftment was determined. The results show that increasing doses of minimal irradiation have a profoundly toxic effect on stem cells irradiated in vitro or in vivo.
