Triethylene melamine-induced sister-chromatid exchange in murine lymphocytes exposed in vivo

Individual and strain differences in patterns of long‐term persistence of urethane‐induced sister chromatid exchanges (sces) in mouse lymphocytes and their relation to carcinogen susceptibility

“…However, even after 180 days, some "outlier" cells with exceptionally high SCEs (> 20), which could not be observed in the cells before treatment, persisted. Previously, Neft et al [1985] demonstrated that multiple injections of urethane induced increased SCEs, which persisted in mouse lymphocytes for more than 100 days. However, there is no report of such long-term persistence of increased SCEs of mouse lymphocytes after a single injection of urethane.…”

“…Several recent studies using rodent animal models have attempted to clarify the relationship between the patterns of persistence of increased SCE frequency and the occurrence of cancer induced by certain chemicals [Neft et al, 1985;Takeshita and Conner, 1985;Allen et al, 1986;Tucker et al, 19861. However, the problem inherent in these models is that the need to sacrifice the animals prevents collection of cytogenetic specimens from individual animals at intervals.…”

“…We used urethane as an appropriate test chemical, since it is a potent carcinogen for various organs in mice [Mirvish, 19681, and its SCE-elevating effect has been studied extensively in this species [Dragani et al, 1983;Sharief et al, 1984;Neft et al, 1985;Allen et al, 19861. We used mice of the ddY and C57BL strains, since they show different responses to the carcinogenic action of this chemical, the former being more susceptible than the latter [Matsuyama and Suzuki, 19681.…”