Alterations in Radiosensitivity of the Haemopoietic System of the Mouse Produced by Extreme Hypothermia

Summary

Mice were given whole-body x-irradiation over the dose-range 0–950 r. Some were irradiated at normal body temperatures and some at body temperatures of 1°c. Others were irradiated at normal body temperatures and then cooled to 1°c and subsequently resuscitated. This communication deals with the state of the haemopoietic system of such animals, as judged by examination of the bone marrow and by peripheral blood counts at periods of up to five days after irradiation. It is shown that hypothermia results in radioprotection of the leucocyte series and their precursors, and it is concluded that this protection is mainly due to concomitant severe hypoxia.