Banding technique used for the detection of chromosomal aberrations induced by radiation and alkylating agents TEPA and epichlorohydrin.

Abstract Blood samples from two healthy donors were exposed, (1) to 200 R of X-rays in G 0 and G 1 S phases of the cell cycle, and (2) to epichlorohydrin 10 −6 M and TEPA 10 −4 M in G 0 and/or in G 1 S adn G 2 phases. Part of the cells was processed for chromosome studies conventionally and the other part by the trypsinization banding technique. Detailed chromosomal analysis showed that, after irradiation, 38.2% of aberrations in G 0 and 18.7% in G 1 S phases escaped cytogenetic detection when the conventional technique was used. After exposures to TEPA and ECHH, 10.9% of abberations were undetectable in G 0 and 3.3% in G 1 S and G 2 phases. The distribution of chromosome breaks was non-random bith after irradiation and after exposure to alkylating agents. However, it differed according to the mutagen used. Some chromosomal segments were broken significantly more frequently than the others (e.g. 9q12), some were resistant to breakage (e.g. the whole Y chromosome). The segments represented by G-negative bands were more fragile than the G-positive and G-variable segments.