Genotoxic exposure assessment by simplified DNA analysis.
School of Public Health, University of Texas, Houston, Texas 1988 Nov; :1-5
A test which was both sensitive and practical was sought to study human exposures to genotoxic agents. The test was based on the changes apparent in the 340 base pair (bp) alphoid sequence subsequently brought about by Eco-R1 restriction of DNA obtained from peripheral leukocytes. Following in-vitro challenge by ionizing radiation or by various chemical agents, the DNA was extracted from human leukocytes. Breakage was induced at the damaged sites of the 340bp alphoid sequence by subjecting it to Eco- R1 restriction and secondary treatment. The distribution of a labeled 340bp probe following electrophoresis and hybridization was used to determine the degree of breakage. When appropriate it may be possible to use other means to quantify the breakage. Efforts were successful in keeping the quantity of blood needed for the analysis to a small amount. Electrophoresis, followed by cerenkov counting, was effective in detecting the action of in-vitro exposures of dimethyl-sulfoxide (67685) on leukocytes. DNA samples extracted from cells exposed to four treatment levels were restricted, radiolabeled, made alkaline, and subjected to gel electrophoresis. Tracks were divided into three regions by excision of the 340bp region and the activity of each was assayed by cerenkov counting. The fraction of the labeled genome heavier than 340bp fell monotonically from 93 to 3 percent as the dimethyl-sulfoxide concentration was raised. The carcinogen N-methyl-N'-nitro-N- nitrosoguanidine (70257) produced similar, but less pronounced, results.
NIOSH-Grant; Reproductive-system-disorders; Nucleic-acids; DNA-damage; Genotoxic-effects; Analytical-methods; Chemical-analysis
Environmental Sciences University of Texas P O Box 20186 Houston, Tex 77225
Final Grant Report
NTIS Accession No.
School of Public Health, University of Texas, Houston, Texas
University of Texas Hlth Sci Ctr Houston, Houston, Texas