Late effects of ionizing radiation on haemopoietic stem cells and possible modification thereof

In experiments with mice it has been found that a radioprotective agent, mexamine (two different forms), administred prior to a whole-body single exposure at a dose of LD0/30 increases the average life of animals and the number of exoCFUs8days and has no influence on the number of exoCFUs12days. Mexamine does not modify the decrease of haemopoietic colonies in sizes in recipients, mice survived acute radiation sickness being used as donors. The share of CFUs8days at the stage of DNA synthesis has been shown to increase with age, as well as in animals which lived for 14 months after irradiation