6,4,4'-trimethylangelicin photoadduct formation in DNA: production and characterization of a specific monoclonal antibody.

The photochemical reactions of 6,4,4'-trimethylangelicin (TMA) with calf thymus DNA and an octanucleotide containing a single thymine have been characterized. HPLC analyses of enzymatically hydrolyzed TMA-DNA showed that isomeric forms of 4',5'-furan-side monoadducts were the major products. To develop monoclonal antibodies Balb c mice were immunized with the TMA-DNA complexed with methylated bovine serum albumin. The resultant antibodies were characterized by enzyme-linked immunosorbent assays (ELISA). The most sensitive antibody (7E3) has high specificity for TMA-DNA, very low cross-reactivity with DNA modified with either 4',5'-dimethylangelicin or 4'-methylangelicin and no cross-reactivity with non-modified DNA or with DNA modified with either 4'-aminomethyl-4,5',8-trimethylpsoralen or 8-methoxypsoralen. To characterize further this antibody, oligonucleotides containing specific TMA photoadducts were isolated from the photoreaction mixture by polyacrylamide gel electrophoresis and used as competitive inhibitors in the ELISA. Autoradiography of the gel showed an intense band corresponding to the 4',5'-monoadduct and two weaker unidentified bands. Antibody 7E3 reacted only with the 4',5'-monoadduct band as would be expected since this photoadduct was the principal photoadduct in the original antigen.

Detection of adducts of deoxyribonucleic acid in white blood cells of roofers by 32P-postlabeling. Relationship of adduct levels to measures of exposure to polycyclic aromatic hydrocarbons.

To assess the utility of adducts of deoxyribonucleic acid (DNA) as biomarkers of exposure to carcinogens in an industrial population, a pilot study of roofers occupationally exposed to polycyclic aromatic hydrocarbons was conducted. DNA isolated from white blood cells of roofers and nonoccupationally exposed comparison subjects matched for age, sex, and smoking status was analyzed for DNA adducts with the use of 32P-postlabeling methods. Occupational exposures to polycyclic aromatic hydrocarbons were assessed by personal air sampling and skin wipes. Ten of the 12 roofers, but only 2 of the 12 comparison subjects, had detectable levels of aromatic DNA adducts in the 32P-postlabeling assay. Among the roofers, the post-shift levels of polycyclic aromatic hydrocarbons in the skin wipes were correlated with the DNA adduct levels. These results suggest that 32P-postlabeling assay may be useful for monitoring internal exposures to complex mixtures of aromatic hydrocarbons in industrial populations.

A pilot study of detection of DNA adducts in white blood cells of roofers by 32P-postlabelling.

To assess the utility of DNA adducts as biomarkers of exposure to carcinogens in an industrial population, a pilot study of roofers occupationally exposed to a mixture of polycyclic aromatic hydrocarbons was conducted. DNA was isolated from peripheral white blood cells of roofers and non-occupationally exposed subjects matched for age, sex and smoking status. Occupational exposures to anthracene, fluoranthene, pyrene, benzanthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[g,h,i]perylene and benzo[k]fluoranthene were assessed by personal breathing zone air sampling and skin wipes. Exposures to benzo[a]pyrene in air of exposed subjects ranged from 0.60 microgram/m3 to 1.39 micrograms/m3, and exposures to total polycyclic aromatic hydrocarbon (the sum of eight hydrocarbons) ranged from 6.0 micrograms/m3 to 13.8 micrograms/m3 on the day before blood collection. In the biomarker studies 10 of 12 roofers, but only 2 of 12 comparison subjects, had detectable levels of aromatic DNA adducts by 32P-postlabelling assay (p less than 0.01). The two non-roofers with detectable adducts had levels at or near the detection limit of 2 adducts per 10(9) nucleotides. In two roofer samples which were studied in a mixing experiment, the major adduct spots did not co-migrate with the guanosine N2 adduct of benzo[a]pyrene diol epoxide. These results suggest that the 32P-postlabelling assay may be useful for monitoring exposures to complex mixtures of aromatic hydrocarbons in industrial populations.