The cytogenetic examination of different groups of children living in regions of Bryansk Province contaminated as a result of the Chernobyl accident

: The frequency of chromosome aberrations (CA) was studied in peripheral blood lymphocytes from healthy children and children with thyreopathology living in the city of Klintsy, Bryansk Province (contamination level up to 5 Ci/km2), and two Moscow groups, respectively. We have observed the elevated number of dicentrics and acentric fragments in cell from children with thyreopathology with respect to those from healthy children living in Klintsy. This fact cannot be explained by influence of disease because there was no difference in cytogenetical markers between the groups of healthy children and children with thyreopathology from Moscow. The number of dicentrics was increased in cells from children with high level of internal contamination (more than 400 nCi) living in Krasnaya Gora (15-40 Ci/km2). It is proposed that the internal irradiation is more important for the CA induction. The symmetrical translocation analysis using the method of fluorescence in situ hybridisation (FISH) has shown the absence of this type of aberrations in cells from children with high level of internal irradiation whereas the translocations frequency in cells from control children was (1.1 +/- 0.4) per 1000 cells.