Heterogeneity in the Clastogenic Response to X-Rays in Lymphocytes from Ataxia-Telangiectasia Heterozygotes and Controls

Details

• Personal Author:
  Kelsey KT ; Little B ; Wara DW ; Wiencke JK
• Description:
  A coded analysis of X-ray-induced chromatid aberrations in lymphocyte cultures from 45 control individuals and 19 ataxia-telangiectasia (A-T) heterozygotes was performed. The distribution of chromatid breaks induced in the late G2 portion of the cell cycle by 60 cGy of X-rays appeared bimodal in the study population. In six controls (13 percent) and in 12 of 19 (63 percent) A-T heterozygotes, the yields of X-ray-induced breaks observed were within the higher mode of the distribution. However, lymphocytes from A-T heterozygotes sensitive to the induction of chromatid breaks by 60 cGy did not contain increased numbers of aberrations following exposure to 20 cGy. The radio-resistant inhibition of DNA synthesis that occurs in A-T homozygotes was not observed in heterozygotes. Co-cultivation experiments showed an increased G2 delay in lymphocytes from an A-T heterozygote whose lymphocytes contained increased X-ray-induced chromatid breaks. The results show a significant association of A-T heterozygosity with G2 chromosomal sensitivity (P less than 0.001; Wilcoxon rank sum test). The measurement of X-ray-induced breaks, however, failed to identify 37 percent of A-T heterozygotes tested. The predicted prevalence of increased sensitivity to X-rays in controls is approximately three- to 30-fold greater than the estimated frequency of A-T heterozygotes in the general population. Therefore, although the increased sensitivity to X-ray-induced chromatid breaks appears to be associated with the A-T-gene, it is not a reliable indicator of A-T heterozygosity. Genetic or environmental factors other than the A-T gene also must be involved in the increased clastogenic response. [Description provided by NIOSH]
• Subjects:
  DNA Environmental Health Genetics Mutagens Occupational Health Safety
• Keywords:
  Author Keywords: Ataxia Telangiectasia Chromosome Breakage DNA-damage Environmental-factors Humans Lymphocytes Mutagenesis X-rays
• ISSN:
  0957-5243
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; Massachusetts ; OSHA Region 1 ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OD - Office of the Director
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  237-245
• Volume:
  3
• Issue:
  3
• NIOSHTIC Number:
  nn:20000997
• Citation:
  Cancer Causes Control 1992 May; 3(3):237-245
• Contact Point Address:
  Department of Epidemiology and Biostatistics, School of Medicine, University of California, San Francisco 94143
• Federal Fiscal Year:
  1992
• Performing Organization:
  Harvard University, School of Public Health, Occupational Health Program, Boston, Massachusetts
• Peer Reviewed:
  True
• Start Date:
  19910930
• Source Full Name:
  Cancer Causes and Control
• End Date:
  19940929
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:47fcaddc317e6c07c089ff89c084f805c71a3d1714c3e06e4b82eb3c97f3a0436b60ab8d80295fc85d4605f13100c82a3aaa1b4ce7b33771726aecd050e54a29
• Download URL:
  https://stacks.cdc.gov/view/cdc/198289/cdc_198289_DS1.pdf
• File Type:
  [PDF - 797.46 KB ]