Lead exposure causes cardiac and vascular damage in experimental animals. However, there
is considerable debate regarding the causal relationship
between lead exposure and cardiovascular dysfunction in humans. Paraoxonase 1 (PON1), a
high-density lipoprotein-associated antioxidant
enzyme, is capable of hydrolyzing oxidized lipids and thus protects against
atherosclerosis. Previous studies have shown that lead and several
other metal ions are able to inhibit PON1 activity in vitro. To investigate whether lead exposure has influence on serum PON1 activity, we
conducted a cross-sectional study of workers from a lead battery
manufactory and lead recycling plant. Blood samples were analyzed
for whole-blood lead levels, serum PON1 activity, and three common PON1 polymorphisms (Q192R, L55M, −108C/T). The mean blood lead level (± SD) of
this cohort was 27.1 ± 15 μg/dL. Multiple
linear regression analysis showed that blood lead levels were
significantly associated with decreased serum PON1 activity (p < 0.001) in lead workers. This negative correlation was more evident
for workers who carry the R192 allele, which has been suggested to be
a risk factor for coronary heart disease. Taken together, our results
suggest that the decrease in serum PON1 activity due to lead exposure
may render individuals more susceptible to atherosclerosis, particularly
subjects who are homozygous for the R192 allele.
Cigarette smoking, aromatic amines and ionizing radiation are known carcinogens of bladder cancer. NAT2 genotype might play a role in bladder cancer carcinogenesis. This hospital-based, case-control study was conducted in Kaohsiung, Taiwan, which neighbors the high incidence region of bladder cancer in the black-foot disease area. A total of 103 cases with diagnosed bladder cancer were collected. For each case, 1 control was selected from the same hospital. A structured questionnaire was applied for all cases and controls. DNA was extracted from peripheral blood cell. The ASO-PCR/RFLP technique was used to determine the NAT2 genotype. For bladder cancer, the significantly excessive risks were observed in regular drinkers (OR = 2.74, 95% CI = 1.28–5.87) and residents of the black-foot disease endemic area (OR = 7.53, 95% CI = 2.16–26.33), and interaction of regular drinking and slow type of NAT2 (OR = 18.04, 95% CI = 2.28–142.80). We suggested that NAT2 genotype might play a role of effect modifier in bladder cancer carcinogenesis.
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