LONG-TERM EFFECTS ON TUMOR-INCIDENCE AND SURVIVAL FROM AM-241 EXPOSURE OF THE BALB C MOUSE IN-UTERO AND DURING ADULTHOOD/

BALB/c mice were given 100, 500 or 1500 Bq/g Am-241 at day 14 of pregn ancy. The offspring were separated from the mothers at birth and follo wed until death. In addition, adult females and one group of males wer e also studied for the effects of Am-241 following treatment with 45-2 13 Bq/g. Adults treated with Am-241 showed significantly shortened sur vival and increased incidence of osteosarcoma (to 40-50%). The data al so suggest that the female mouse is more susceptable to induction of o steosarcoma than the male. There was also a significant increase in os teosarcoma, all bone rumours, all sarcomas, and all leukaemias in the offspring from the contaminated mothers, although this appeared to occ ur independently of dose. Calculations of the number of osteosarcomas induced per Gy varied for contamination of adult mice between 0.2 and 0.01 and for the offspring between 6 and 0.6. Thus, offspring seemed t o be about 10 times more at risk if osteosarcomas induced per mouse Gy are compared. Surprisingly, offspring from mothers treated with Am-24 1 displayed a longer survival time than controls, possibly due to fewe r deterministic lung diseases appearing early in life.