CHROMOSOME-DAMAGE IN UNDERGROUND COAL-MINERS - DETECTION BY CONVENTIONAL CYTOGENETIC TECHNIQUES AND BY SUBMITTING LYMPHOCYTES OF UNEXPOSED INDIVIDUALS TO PLASMA FROM AT-RISK GROUPS

Chromosome abnormalities and the mitotic index in lymphocyte cultures and micronuclei in buccal mucosa cells were investigated in a sample o f underground mineral coal miners from Southern Brazil. A decreased mi totic index, an excess of micronuclei and a higher frequency of chromo some abnormalities (fragments, polyploidy and overall chromosome alter ations) were observed in the miners when compared to age-paired normal controls from the same area. An alternative assay for clastogenesis i n occupational exposition was tested by submitting lymphocytes from no n-exposed individuals to a pool of plasmas from the exposed population . This assay proved to be very convenient, as the lymphocytes obtained from the same individuals can be used as target as well as control ce lls. Also, it yielded a larger number of metaphases and of successful cultures than with common lymphocyte cultures from miners. A significa ntly higher frequency of chromatid gaps, fragments and overall alterat ions were observed when lymphocytes from control subjects were exposed to miner plasma pools. Control plasma pools did not significantly ind uce any type of chromosome alterations in the cultures of normal subje cts, thus indicating that the results are not due to the effect of the addition of plasma pools per se.