title: [Sister chromatid exchanges, during x-irradiation, in the blood lymphocytes of patients with hereditary diseases and radioresistant DNA synthesis].
abstract: X-ray irradiation induced sister chromatid exchanges (SCE) in blood lymphocytes from patient with Down's syndrome and adult progeria (in both the cases radioresistant DNA synthesis takes place). In these diseases, likely as upon form II of xeroderma pigmentosum (the replicative DNA synthesis is radioresistant), X-ray irradiation lowers the rate of SCE compared with that in the control, then the SCE rate rises with the increase in radiation dose, reaching the rate of SCE in non-irradiated cells. In normal lymphocytes (in which ionizing radiation inhibits the replicative synthesis of DNA) the rate of SCE rises with the rise of radiation dose. Thus, the rate of SCE in X-ray irradiated lymphocytes is in reverse dependence with radioresistance of replicative synthesis of DNA. The data obtained are explained in accordance with the replicative hypothesis of the SCE nature (Painter, 1980a): in cells of patients with Down's syndrome, xeroderma pigmentosum form II and progeria of adults the time of existence of partly replicated clusters of replicons is decreased due to radioresistant replicative synthesis of DNA, but the presence of partly replicated clusters of replicons is necessary for SCE formation. Therefore the rate of SCE in X-irradiated cells of these patients decreases.
authors.forename: N M
authors.initials: NM
authors.lastname: Pleskach
authors.forename: M I
authors.initials: MI
authors.lastname: Andriadze
authors.forename: V M
authors.initials: VM
authors.lastname: Mikhel'son
authors.forename: V D
authors.initials: VD
authors.lastname: Zhestianikov
mesh_terms: D000293:Adolescent; D000328:Adult; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis / Q000528:radiation effects*; D004261:DNA Replication / Q000528:radiation effects*; D004314:Down Syndrome / Q000097:blood / Q000235:genetics*; D006801:Humans; D008214:Lymphocytes / Q000528:radiation effects*; D008875:Middle Aged; D011836:Radiation Tolerance; D012854:Sister Chromatid Exchange / Q000528:radiation effects*; D014466:Ultraviolet Rays; D014898:Werner Syndrome / Q000097:blood / Q000235:genetics*
chemical_list: D004247:DNA
vernacular_title: Sestrinskie khromatidnye obmeny pri rentgenovskom obluchenii v limfotsitakh krovi bol'nykh nasledstvennymi zabolevaniiami s radiorezistentnym sintezom DNK.