FURTHER OBSERVATIONS ON LATE SOMATIC EFFECTS OF RADIOMIMETIC CHEMICALS AND X-RAYS IN MICE.

Abstract

Young adult female RF mice were subjected to four successive midlethal doses of nitrogen mustard (HN2), triethylene melamine (TEM), 1,4-dimethanesulfonoxybutane (myleran), or whole-body x-rays. The agents were given at 14-day intervals, and the survivors were observed for effects on longevity and on the incidence of late occurring diseases. The percentages of mice dying within 30 days after treatment in the various groups were: TEM, 12.5%; HN2, 10%; myleran, 3%; x-rays, 1%; and control, 1%. The life-span of 30-day survivors was shortened in all treated groups, with mean survival times as follows: x-rays, 355 days; TEM, 427 days; HN2, 490 days; myleran, 511 days; and controls, 632 days. Although all the agents were highly oncogenic, the decrease in longevity was not attributable solely to neoplasia, but was correlated with premature mortality in various diseases associated with aging. Thymic lymphomas were induced by all agents, but myeloid leukemia only by x-rays. The incidence of ovariant tumors was increased by TEM, myleran, and x-rays. The incidence of pulmonary adenomas was increased by HN2 and TEM. All agents caused premature development of lens opacities, but only myleran and x-rays induced lens changes significantly more severe than those developing spontaneously in senile controls.