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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.
 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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