INTERACTION OF NICKEL WITH MUTAGENS IN THE INDUCTION OF SISTER-CHROMATID EXCHANGES IN HUMAN-LYMPHOCYTES

In this study, individual treatments of human lymphocytes with Ni(II) [0.5 - 25 mu M], Cr(VI) [0.65 - 1.30 mu M], UV-light or X-rays induced SCEs in a dose-dependent fashion, and combined treatments of Ni(II) w ith Cr(VI), UV-light or X-rays interacted antagonistically. Nickel, at environmentaly relevant exposure levels, can have the effect in compl ex mixtures of reducing an otherwise positive SCE response and could l ead to underestimating human exposures to certain classes of chemicals or radiation. Furthermore, our data indicate that antagonism may occu r when human lymphocytes are exposed simultaneously to Ni(II) and Cr(V I), suggesting an explanation for epidemiological studies reporting co nflicting results for cytogenetic effects in lymphocytes of workers ex posed to chromium and nickel.