Distribution of radiation induced lesions in human chromosomes and dose-effect relation analysed with G-banding

Abstract

Human female lymphocytes were exposed to X-rays in vitro at 7 different doses between 40-280 R. In 830 metaphases chromosome analyses were carried out with either conventional staining or G-banding, respectively. 486 breakpoints are non-randomly distributed between chromosomes and chromosome arms. An excess of lesions was present in chromosomes 1 and 5 or in 1p. 85% of the lesions were located in G-negative bands (pale G-bands). 29% of all lesions appeared in either the last terminal pale band (21%) or in the centromere region (8%). With regard to an application of G-banding for a biological dose-estimation, the dose-response relations of dic and ace were analysed. Although G-banding enables detailed analysis of the whole karyotype it cannot be recommended for cytogenetic routine analyses in medical radioprotection monitoring, without suitable automated scoring techniques. Dose estimations based on the frequency of dic and carried out with conventional staining cannot be essentially improved at present with banding. Nevertheless, by banding criteria for a correct evaluation of other aberration types, e.g. ace, can be provided. This is a prerequisite for the calculation of representative dose-effect curves.

Analysis for DNA-proportional Distribution of Radiation-induced Chromosome Aberrations in Various Triple Combinations of Human Chromosomes Using Fluorescencein SituHybridization

“…The excess participation of chromosome I in stable translocations reported by Lucas et al (1992) and Sachs et al . (1993) from G-banding analyses as well as the findings of excess lesions in chromosome 1, particularly in ip by Bauchinger and Gotz (1979) or by Barrios et al . (1989) are not confirmed by the present findings and by the data from Lucas et al .…”

Analysis of chromosome aberrations in human peripheral lymphocytes induced by 5.4 keV x-rays

“…In metaphases of the first cell cycle division containing several fragments together with asymmmetrical exchange aberrations, only one fragment is assigned to each exchange. This seems justified since in a previous irradiation experiment which was analysed with G-banding, we found 90% of major exchanges to be complete [16]. The remaining fragments were scored as excess acentrics.…”

Effect of temperature during irradiation on the level of micronuclei in human peripheral blood lymphocytes exposed to X-rays and neutrons

“…Historically, the oldest data come from cytogenetic studies, where the frequencies of radiation-induced chromosome breaks were analysed on G-banded chromosome slides. The majority of results point towards a higher frequency of breaks in the light bands which correspond to euchromatin as compared to heterochromatic dark bands (Holmberg and Jonasson 1973, Bauchinger and Gö tz 1979, Martínez-Ló pez et al 1999. In a more recent study with the use of 19 cancer cell lines Chavaudra et al (2004) found that the surviving fraction at 2 Gy decreased linearly with the extent of chromatin relaxation: 1% chromatin decondensation produced a loss of about 1.5% surviving fraction.…”