COMET ASSAY ON CHILDRENS LEUKOCYTES 8 YEARS AFTER THE CHERNOBYL DISASTER

DNA damage, mainly single strand breaks, was evaluated by single cell gel electrophoresis, in leukocytes of 36 healthy and 14 thyroid cancer -affected children prior to radio-therapy. The children come from the Gomel region, one of the areas most heavily radio-contaminated by the Chernobyl fallout. In addition, leukocytes were treated with a challen ge dose of bleomycin (BLM, 1.5 mu g/ml), to assess the presence of an adaptive response (AR) potentially resulting from chronic exposure to radionuclides. As controls, 13 children living in Pisa (Italy) were en rolled in the study. Children with thyroid cancer show higher (p < 0.0 01) DNA damage than healthy ones. No difference was found between heal thy children from Gomel and from Pisa. A reduction in the response to BLM was significantly linked to low plasma levels of FT4 hormone (p < 0.0001), to the presence of the tumor (p < 0.002), to being female (p < 0.02), and to a higher Cs-137 body burden (p < 0.03). (C) 1998 Elsev ier Science B.V. All rights reserved.