[Electrophoretic detection of protein p53 in human leukocytes]. / Elektroforeticheskoe vyiavlenie belka p53 v leikotsitakh cheloveka.

Protein (m.v. 53 kilodalton) with electrophoretic mobility identical to that of protein detected in leukocytes of patients with Down's syndrome and of protein p53 obtained from mouse ascites carcinoma was demonstrated by polyacrylamide gel electrophoresis in healthy donors' leukocytes cultured with PHA and in peripheral blood of patients with chronic myeloleukemia. Appearance of the class p53 proteins in leukocytes of patients may be connected with the presence in their blood of the population of immature or transformed, proliferating or merely DNA-synthesizing leukocytes, particularly those amplifying the gene that codes protein p53.

[Comparison of the level of sister chromatid exchanges and chromosome aberrations induced by chemical mutagens in vitro and in vivo]. / Sopostavlenie urovnia sestrinskikh khromatidnykh bmenov i khromosomnykh aberratsii, indutsirovannykh khimicheskimi mutagenami in vitro i in vivo.

The paper presents results of a study of a dose dependence of induction of SCE and chromosomal aberrations at the exposure of human lymphocytes in vitro and bone marrow cells of mice in vivo to 5 alkylating chemicals. The efficiency of SCE induction in vitro is found to be 300-30 times as high as that of arising of chromosomal aberrations. The same regularity is observed in experiments in vivo, but the ratio is reduced to 60-20 times.

[Electrophoretic analysis of the characteristics of the protein composition of leukocytes from Down's syndrome patients]. / Elektroforeticheskii analiz osobennostei belkovogo sostava leikotsitov bol'nykh s sindromom Dauna.

Protein with a molecular mass of 53000 daltons undetectable in healthy persons was identified by electrophoresis in peripheral blood leukocytes of patients with Down's syndrome. The protein was completely extracted with 0.4 N HCl from leukocyte homogenates and was found to be identical, as regards electrophoretic mobility, to protein detected in two patients with chronic myeloblastic leukemia. The causes of discrepancy between theoretically expected and electrophoresis-revealed differences in protein composition of normal and trisomal cells.

[Comparative effectiveness in the induction of sister chromatid exchanges and chromosome aberrations]. / Sravnitel'naia éffektivnost' induktsii sestrinskikh khromatidnykh obmenov i khromosomnykh aberratsii.

The dose curves for 5 chemicals were studied to compare the efficiency of induction of SCEs and chromosomal aberrations by "polycentric" mutagens. The number of SCEs was found to increase linearly with the dose while that of chromosomal aberrations--nonlinearly. The efficiency of SCEs induction by these mutagens was found to be 25-50 times as high as in the induction of chromosomal aberrations. Division of alkylating mutagens into "monocentric" and "polycentric" is shown to be useful. It reflects their different efficiency in damaging one or simultaneously two DNA strands. The correlation between SCEs and formation of aberrations of the chromatid type is stated.

[Quantitative evaluation of the effectiveness of the formation of sister chromatid exchanges and chromosome aberrations as affected by chemical mutagens]. / Kolichestvennaia otsenka éffektivnosti obrazovaniia sestrinskikh khromatidnykh obmenov i khromosomnykh aberratsii pri deistvii khimicheskikh mutagenov.

Dose curves of five chemicals were studied to compare the efficiency of SCE and chromosomal aberration induction by different chemical mutagens. SCEs were found to increase linearly with the dose, whereas chromosomal aberrations--nonlinearly. Using regression coefficients obtained from the dose curves it was found that the efficiency of the studied chemical mutagens in induction of SCEs is 100-300 times as high as that in the induction of chromosomal aberrations.

[Correlation of the sister chromatid exchange level with chromosome aberrations induced by chemical mutagens in vivo]. / Korreliatsiia urovnia sestricheskikh khromatidnykh obmenov i khromosomnykh aberratsii, indutsirovannykh khimicheskimi mutagenami in vivo.

The data on the dose dependencies of the induction of sister chromatid exchanges (SCE) and chromosomal aberrations during exposure of mouse bone marrow cells in vivo to 5 alkylating substances are provided. The efficacy of SCE induction was found to be higher than that of chromosomal aberrations. It was established that SCE induced by chemical mutagens in vivo and in vitro are more sensitive and stable tests than chromosomal aberrations.

[Comparison of the levels of chromosome aberration and sister chromatid exchange induced by chemical mutagens in vitro]. / Sopostavlenie urovnia sestrinskikh khromatidnykh obmenov i khromosomnykh aberratsii, indutsirovannykh khimicheskimi mutagenami in vitro.

Dose dependencies of the induction of sister chromatid exchanges (SCEs) and chromosome aberrations were studied under in vivo exposure of mouse bone marrow cells to 5 alkylating agents. The efficacy of the induction of SCEs for all the substances was 20 to 60 times higher than that of the induction of chromosome aberrations. It was demonstrated that SCEs induced by chemical mutagens in vivo and in vitro are more sensitive tests than chromosome aberrations.