SISTER-CHROMATID EXCHANGES INDUCED BY CHLORAMPHENICOL ON BOVINE LYMPHOCYTES

The induction of sister-chromatid exchanges (SCE) was studied in bovin e lymphocyte cultures treated with chloramphenicol (CAP), an antibioti c agent in wide use in human and animal therapy. A total of six indivi duals, matched for sex, race, age and environmental conditions, were u sed for the analysis. Chloramphenicol was tested at four different con centrations (5, 10, 20 and 40 mug/ml) and acted for the last 24 h of t he culture. Each experiment included two,animals, each of which was ex posed to all chloramphenicol doses, for a total of three repetitions. The results of the corresponding analysis of variance showed that this chemical had a small but statistically significant effect on the SCE frequency. In addition, the lymphocyte cultures responded strangely to this chemical: the highest SCE induction was produced by the lowest d ose. However, the study of high frequency cells did not show the prese nce of this kind of cell which could explain this chloramphenicol resp onse. In addition, chloramphenicol induced a high delay in the cell cy cle.