LATE EFFECTS OF RADIOMIMETIC AGENTS 



173 



agent appearing oncogenic for aU organs (Table I). Effects on the lens tended 

 to paraUel effects on the life-span, but the cataractogenic effects of HN2 were 

 barely detectable (Fig. 3). 



100 200 300 400 500 600 700 800 900 1000 

 Age (doys) 



Fig. 2. Longevity of thirty-day survivors without neoplasms, in relation to time after 

 treatment. Q X-rays; A, TEM; •, HN2; O, controls. 



lOOn 



::s 80- 



t eo-\ 



o 



D 

 CL 

 O 



40 



E 



° 20- 



100 



200 300 400 500 600 700 800 

 Age (days) 



Fig. 3. Average severity of lens opacities in relation to time after treatment. Q. X-rays; 

 A, TEM; •, HN2; O, controls. 



DISCUSSION 



These results indicate that the "late effects syndrome" caused by ionizing 

 radiation is not peculiar to this agent alone but may be induced by radio- 

 mimetic chemicals. It is evident, however, that neither of the compounds 

 reproduced all the effects of X-rays at the dose levels tested. Instead, the 

 effects of these agents varied on different organs. Whether such variations 

 resulted from differences in the uptake and distribution of the chemicals in 

 different organs or from other factors is not yet known. 



