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With the aim of determine and characterize chromosomal alterations in human lymphocytes induced by x-rays, an experimental study was performed with auto-control in four healthy donors (two males and two females). Peripheral blood was drawn, and divided in six aliquots: five of them were irradiated with 0.5, 1, 2, 3 and 4 Gy using a linear accelerator and one aliquot was used as control for each donor. The chromosomal analysis was carried out with the "G banding technique". It was observed that as the irradiation doses were raised, the abnormal metaphases and frequency of chromosomal alterations increased as well. The majority of chromosomal alterations were of the structural type, of which the most relevant ones were translocations, fragile sites and deletions. A significant difference was observed between the exposed and non-exposed groups with regard to the irradiation doses and the apparition of chromosomal alterations (p < 0.05). Chromosome 1 was more frequently involved in structural chromosomal alterations, followed by chromosomes 3, 10, 6, 7 and 9. The results presented in this study indicate that chromosomal alterations induced by acute exposure to x-rays increase linearly once the irradiation doses are raised. Therefore, the cytogenetic analysis can be considered as a useful tool for the control of the absorbed radiation dose and its biologicals effects in men.

Recent research have demonstrated that homozygotic and heterozygotic patients with ataxia telangiectasia (AT) show chromosomal rupture. Taking in consideration this characteristic, a study was designed, inducing chromosomal breaks in granulocytes from patients with AT, and heterozygotic carriers of AT compared with a group of healthy individuals. The number of chromosomic ruptures induced by 14 doses of radiation at 125 KV and 125 mA, was measured in all of them. Results suggest significant differences in the number of chromosomal structural alterations induced by radiation in granulocytes from heterozygotic carriers of AT, similar to structural alterations in lymphocytes from patients with AT. It is demonstrated that these alterations occur preferentially in one group C chromosome, both in homozygotic and heterozygotic patients with AT.