Autologous Bone-Marrow Implantation after Fast Neutron Irradiation of Dogs

Several investigators have suggested that the course of events leading to death in mice irradiated by fast neutrons involves the gastrointestinal tract. The evidence in support of this position is to be found in the early time of death of neutronirradiated mice (1) and in the experimental observations which showed that bonemarrow implantation is less effective in supporting mice after normally lethal neutron irradiation (2). Studies to determine the LD50 in neutron-irradiated dogs failed to demonstrate an enhanced gastrointestinal component at the lower radiation doses (3); however, the technique of autologous bone-marrow implantation developed by us (4) provides a means for increasing the dose to the animal without causing its death from bone-marrow failure. Under these conditions the gastrointestinal response may be observed while functioning hematopoietic tissue is maintained.