Comparative Late Somatic Effects of Some Radiomimetic Agents and X-Rays

Abstract

Young adult RF female mice were given midlethal doses of nitrogen mustard (HN2), triethylene melamine (TEM), and whole-body X-rays, and the survivors observed for longevity and incidence of late-occurring diseases. The life span was shortened by all treatments. The mean survival time was as follows: X-rays, 396 days; TEM, 508 days, HN2, 561 days; and controls, 638 days. The reduction in longevity was not attributable to neoplasia induction but was correlated with an increase in the age-specific death rate from diseases of all types. The increase varied in degree from one disease to another. Hence, the effects were not equivalent to premature aging in the simplest sense. TEM markedly increased the total incidence of thymic lymphomas, pulmonary adenomas, and lung tumors. HN2 markedly increased the total incidence of pulmonary adenomas and ovarian tumors. X-rays markedly increased the total incidence of thymic lymphomas and ovarian tumors but reduced the total incidence of pulmonary adenomas. All agents caused premature lens opacities, but X-rays alone induced changes of greater severity than those occurring spontaneously in senile controls.