Correlation between Deoxyribonucleic Acid Synthesis and Mortality following Irradiation in Mice

DURING the past few years there has been renewed interest regarding the kinetics of repair following irradiation, both for animals exposed to whole-body irradiation and for several in vitro systems. It was previously thought that repair following irradiation progressed in an exponential manner such that the amount of residual injury present continuously decreased with time 1 . The method usually used to examine this effect is the ‘paireddose’ technique in which animals (or other systems) are given an initial sub-lethal exposure which is followed at varying time intervals by a second, or challenging, dose. Injury is estimated by comparing the response of the group which received the paired doses with controls that received only single exposures.