Bone-marrow Syndrome in CBA Mice Exposed to Fast Neutrons of i.o MeV Mean Energy

Summary

After whole-body exposure to fast neutrons of high LET in the lethal dose-range (LD_{50/30 d} 351 ± 2 rads) male mice of the inbred CBA strain die mostly between 8 and 15 days after irradiation. Death is mainly due to haematopoietic damage, as evidenced by the protection afforded by syngeneic bone-marrow transplantation. By increasing the neutron dose into the supralethal range, the effectiveness of bone-marrow therapy is decreased by the growing prevalence of the intestinal syndrome (LD_{50/5 d} 452 ± 4 rads). Female mice have the same sensitivity as regards haematopoietic damage (LD_{50/30 d} 348 ± 2 rads) but are slightly more sensitive to intestinal injury (LD_{50/5 d} 423 ± 3 rads). In spite of the bone-marrow transplantation, the probability of death between 10 and 15 days also increases with neutron dose, presumably as a result of the severe damage to the gastric epithelium, which appears at the same time.