Liquid-holding experiments with human peripheral lymphocytes. II. Experiments with trenimon and 1-beta-D-arabinosylcytosine.

Liquid holding of trenimon-treated human peripheral lymphocytes in the G0 stage of the cell cycle leads to an elevation in the frequencies of chromosome aberrations and a decrease in the frequencies of chromatid aberrations. The frequencies of aberrant metaphases are not influenced significantly under these experimental conditions. Storage of trenimon-treated cells in the presence of 1-beta-D-arabinosylcytosine (araC) leads to an additional increase in the frequencies of chromosome-type aberrations, with an increase in the frequencies of aberrant metaphases as well. These findings are interpreted as DNA double-strand breaks being formed during the repair of damaged DNA, and that araC exaggerates this effect by inhibiting repair. AraC does not influence the frequencies of SCEs significantly, which indicates that either the lesions or the repair pathways leading to chromosome aberrations are different from those leading to SCEs.