Increased SCE inducibility by low doses of methylcholanthrene in lymphocytes obtained from patients with Down's...

The inducibility of sister-chromatid exchanges (SCEs) following 3-methylcholanthrene (MC) treatment of normal human peripheral blood lymphocytes and of in vitro cultured normal human embryo fibroblasts, as well as peripheral blood lymphocytes of patients with Down's disease and of fibroblasts of an embryo with trisomy 21 has been investigated. 10(-6) M MC treatment increased the frequency of SCEs by 2.5 in the case of Down lymphocytes when compared to the healthy control. The fibroblasts with trisomy 21, however, did not show an increased sensitivity to MC treatment when compared with normal fibroblasts, expressed in the number of SCEs per nucleus found in the cells.