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Persistently elevated sister chromatid exchanges in ethylene oxide-exposed primates: the role of a subpopulation of high frequency cells.

Kelsey KT; Wiencke JK; Eisen EA; Lynch DW; Lewis TR; Little JB
Cancer Res 1988 Sep; 48(17):5045-5050
The persistence of ethylene-oxide (75218) induced sister chromatid exchanges was studied in a group of cynomolgus-monkeys 6 years after termination of exposure to the alkylating agent. The animals had been exposed to 50 or 100 parts per million (ppm) ethylene-oxide for 7 hours per day, 5 days per week, over a 2 year period extending from 1979 to 1981. The immediate results of the longterm exposure were a tripling of the background frequency of sister chromatid exchanges. Six years post exposure blood was collected from the femoral vein of 36 adult male monkeys, and lymphocyte cultures were again assessed for the frequency of sister chromatid exchanges. Cells showing more than 40 sister chromatid exchanges were defined as high frequency cells. The mean number of sister chromatid exchanges in the 50ppm dose group ranged from 8.52 to 12.76 in 1981 and from 6.87 to 8.71 in 1987. A two percent incidence of high frequency cells was determined in one of seven 50ppm animals in 1981 as compared to an incidence of between 1 and 3 percent for six of seven animals in 1987. The mean number of sister chromatid exchanges in the 100ppm animals ranged from 11.68 to 17.42 in 1981 and from 7.08 to 12.03 in 1987. Four of five 100ppm animals showed exchange frequencies of greater than or equal to 2 percent in 1981 as compared to seven of seven animals in 1987. The authors conclude that inhalation exposure to ethylene-oxide results in the prolonged elevation of sister chromatid exchanges and is associated with enhancement of the fraction of cells with high frequencies of sister chromatid exchanges.
NIOSH-Author; Laboratory-animals; Genetics; Oxides; Mutagens; Genotoxic-effects; Carcinogens; Alkylating-agents; Toxic-gases; Long-term-study
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Cancer Research
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