Sensibilidade cromossômica à bleomicina em linfócitos de pacientes com síndrome de down, nas fases G0, G1 e S do ciclo celular
DOI:
https://doi.org/10.5902/2179460X26753Abstract
Lymphocytes from patients with Down Syndrome (OS) present an increased frequency of chromosome aberrations after exposition to ionizing radiation at G0 and G1 phases of the cell cycle. However, OS lymphocytes irradiated or treated with bleomycin (BLM) at G2 phase do not present a significant increase of aberration's frequency. BLM is a radiomimetic drug that has been used in cytogenetics experiments to verify the individual capacity of DNA repair. The aim of this study was to analyse. the chromosome sensitivity from OS patients to BLM, at G0, G1 and S phases of the cell cycle. Lymphocytes cultures were set up, with and without the drug, from 4 OS patients and 4 normal individuals, all of the male sex and age below 10. One hundred metaphases were analysed for each kind of culture for each individual and the chromosomal and/or chromatidic aberrations were registered. The results obtained show a higher frequency of dicentrics, rings, acentrics and double minutes in OS cells at G0 and G1 phases, but not at S phase, in relation to cells from normal individuals. Possibly, the phase of the cell cycle in which the cell is irradiated or treated is the main factor involved in chromosomal sensitivity of lymphocytes from OS patients.
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