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Benzidine
is a known human carcinogen and till 1990s was used as an
intermediate in the synthesis of azo dyes. Formation of
adducts with DNA, proteins and hemoglobin is an important
marker of exposure to genotoxic chemicals and it may be an
early indicator of development of cancer. In collaboration
with NCI/NIH and University of Cincinnati Medical Centre,
USA., four DNA adducts in exfoliated urothelial cells have
been identified in the workers exposed to
benzidine and benzidine based dyes. Of these, the predominant
adduct which co-chromatographed with a synthetic
N-(3¢-phosphodeoxyguanosin-8-yl)-N¢-acetylbenzidine
standard and was the only adduct that was significantly
associated with total benzidine urinary metabolites (r=0.68,
p<0.0001). To the best of our knowledge, this is the first
report to show that benzidine forms adducts in urothelial
cells of the exposed humans and the predominant adduct formed
is N¢-acetylated. For the analysis of excretion pattern
of benzidine and its acetylated metabolites, an isotope
dilution mass spectrometric technique using capillary
GC/negative ion chemical ionization which possess a detection
limit as low as 0.5, 0.8 and 1.5 ppt for benzidine,
N-acetylbenzidine and N,N’-acetylbenzidine,
respectively was developed. The findings demonstrated the
usefulness of these non-invasive techniques for
exposure/effect assessment in occupational settings.
 Identification
of Carcinogen-DNA Adducts in Benzidine Exposed Workers
A New Multi-Method
Ergonomics Review Technique (MMRT) for Work Analysis in
Industry
Determination of Heat Transfer Coefficients for Application of
Human Heat Stress Assessment
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