Environmental and occupational risk factors for lung cancer

Lung cancer is the world's leading cause of cancer death. It is primarily due to the inhalation of carcinogens and highly accessible to prevention by diminishing exposures to lung carcinogens. Most important will be the complete cessation of exposure to cigarette smoke (first and second hand) and to asbestos. Two environmental exposures--radon in homes and arsenic in drinking water--cannot be totally avoided, but people in certain geographical regions would greatly benefit from a reduction in exposure magnitude. And last but not least, workers all over the world deserve that preventive measures at the workplace are observed with regard to exposures, such as arsenic, beryllium, bis-chloromethyl ether (BCME), cadmium, chromium, polycyclic aromatic hydrocarbons (PAHs), and nickel.

Evaluation of level of DNA damage in blood leukocytes of non-diabetic and diabetic rat exposed to cigarette smoke

The objective of the present study was to use the comet assay to evaluate the steady-state level of DNA damage in peripheral blood leukocytes from diabetic and non-diabetic female Wistar rats exposed to air or to cigarette smoke. A total of 20 rats were distributed into four experimental groups (n=5 rats/group): non-diabetic (control) and diabetic exposed to filtered air; non-diabetic and diabetic exposed to cigarette smoke. A pancreatic beta (beta)-cytotoxic agent, streptozotocin (40 mg/kg b.w.) was used to induce experimental diabetes in rats. Rats placed into whole-body exposure chambers were exposed for 30 min to filtered air (control) or to tobacco smoke generated from 10 cigarettes, twice a day, for 2 months. At the end of the 2-month exposure period, each rat was anesthetized and humanely killed to obtain blood samples for genotoxicity analysis using the alkaline comet assay. Blood leukocytes sampled from diabetic rats presented higher DNA damage values (tail moment=0.57+/-0.05; tail length=19.92+/-0.41, p<0.05) compared to control rats (tail moment=0.34+/-0.02; tail length=17.42+/-0.33). Non-diabetic (tail moment=0.43+/-0.04, p>0.05) and diabetic rats (tail moment=0.41+/-0.03, p>0.05) exposed to cigarette smoke presented non-significant increases in DNA damage levels compared to control group. In conclusion, our data show that the exposure of diabetic rats to cigarette smoke produced no additional genotoxicity in peripheral blood cells of female Wistar rats.

DNA damage and integrity of UV-induced DNA repair in lymphocytes of smokers analysed by the comet assay

DNA damage was assessed in smoker lymphocytes by subjecting them to the single cell gel electrophoresis (SCGE) assay. In addition to the appearance of comet tails, smoker cells exhibited enlarged nuclei when analysed by the comet assay. On comparing basal DNA damage among smokers and a non-smoking control group, smoker lymphocytes showed higher basal DNA damage (smokers, 36.25+/-8.45 microm; non-smokers, 21.6+/-2.06 microm). A significant difference in DNA migration lengths was observed between the two groups at 10 min after UV exposure (smokers, 65.5+/-20.34 microm; non-smokers, 79.2+/-11.59 microm), but no significant differences were seen at 30 min after UV exposure (smokers, 21.13+/-10.73 microm; non-smokers, (27.2+/-4.13 microm). The study thus implies that cigarette smoking perhaps interferes with the incision steps of the nucleotide excision repair (NER) process. There appeared be no correlation between the frequency of smoking and DNA damage or the capacity of the cells to repair UV-induced DNA damage that suggests inherited host factors may be responsible for the inter-individual differences in DNA repair capacities. The study also suggests monitoring NER following UV insult using the SCGE assay is a sensitive and simple method to assess DNA damage and integrity of DNA repair in human cells exposed to chemical mutagens.

Somatic chromosome mutations and morphological abnormalities in sperms of boars

Frequencies of chromosomally aberrant peripheral blood lymphocytes and morphologically abnormal spermatozoa were investigated in 10 boars from each of 11 A.I. centres. Highly significant differences were found between A.I. centres concerning both chromosomally aberrant cells and morphologically abnormal sperms. A significant correlation was found for the overall frequency of aberrant lymphocytes and morphologically abnormal sperms in A.I. centres. The coefficient of correlation was 0.675 (p = 0.022). No significant correlation was found when the 110 boars were evaluated regardless of the A.I. centre.