Oxidative stress and DNA damage in agricultural workers after exposure to pesticides

Background: Recent epidemiological studies on workers describe that exposure to pesticides can induce oxidative stress by increased production of free radicals that can accumulate in the cell and damage biological macromolecules, for example, RNA, DNA, DNA repair proteins and other proteins and/or modify antioxidant defense mechanisms, as well as detoxification and scavenger enzymes. This study aimed to assess oxidative stress and DNA damage among workers exposed to pesticides. Methods: For this purpose, 52 pesticide exposed workers and 52 organic farmers were enrolled. They were assessed: the pesticide exposure, thiobarbituric acid reactive substances (TBARS), total glutathione (TG), oxidized glutathione levels (GSSG), and 8-oxo-7,8-dihydro-2\u2032-deoxyguanosine (8-oxodG), levels. Results: Correlation between pesticide exposure was positively associated with high TBARS and 8-oxodG levels (p < 0.001). A negative association was founded with TG and GSSG and pesticide exposure. Conclusions: The present investigation results seem to indicate a mild augment in oxidative stress associated with pesticide exposure, followed by an adaptive response to increase the antioxidant defenses to prevent sustained oxidative adverse effects stress

Absence of PCR-detectable human papilloma virus in erythroplasia of Queyrat using a comparative control group

Objectives High-risk human papillomavirus (HPV) types have been linked with genital carcinomas. However, the exact relation between HPV and erythroplasia of Queyrat (EQ), for example, in-situ carcinoma of the glans and prepuce, is still unclear. Thw aim of this study was to detect the presence of lesional HPV-DNA in patients with EQ. Methods Paraffin-embedded biopsies were obtained from the glans or inner foreskin of 11 adult uncircumcised patients (mean age 67.7 years; range 57-79) with EQ. An equal number of randomly selected uncircumcised healthy control patients underwent a single brush cytology smear of the penile mucosa. Biopsy specimens and brushings were then assayed by a highly sensitive two-step nested PCR technique based on MY11/MY09 consensus primers and general GP5 +/GP6+ PCR primers, followed by cycle sequencing. Statistical evaluation was performed using conditional logistic regression analysis. Results None of the EQ or control samples proved to be positive for the presence of HPV-DNA. Conclusions The findings do not support the hypothesis that there is a considerable risk of EQ development in patients with HPV infection. The prevalence of HPV infection in patients with EQ has rarely been investigated and available data are relatively scant and controversial. Therefore, the relation between HPV infection and the risk of progression of EQ into squamous cell carcinoma remains a matter of debate, and further investigations are needed in order to confirm the role of HPV in delineating this risk

BETA-2-GLYCOPROTEIN I IS GROWTH REGULATED AND PLAYS A ROLE AS SURVIVAL FACTOR FOR HEPATOCYTES

Beta-2-glycoprotein I (beta(2)GPI) is mainly produced by the liver and is found in plasma partially associated to lipoproteins. Although various properties have been attributed to this protein, its physiological role remains still unclear. We investigated its expression in cultured liver cells and in regenerating liver. Expression studies in HepG2 cells demonstrate that beta(2)GPI mRNA is regulated in a cell cycle-dependent manner, with very low expression in low cycling conditions and increasing levels in proliferating cells. p21 WAF-dependent growth arrest, induced by butyrate treatment, down-regulate beta(2)GPI mRNA levels. Immunolocalization in normal rat liver shows a non-homogeneous pattern, being mainly present in the centrolobular area; post-hepatectomy regenerating rat liver is uniformly immunostained and mitotic elements show the highest protein expression. Albumin gene expression, studies as control liver specific product, was not affected by sodium butyrate induced growth arrest. As previously reported for endothelial cells, beta(2)GPI behaves as survival factor for HepG2 cells: when increasing amounts of the protein (10-50 microg) have been added to serum deficient cultured liver cells a progressive reduced cell loss was observed. In conclusion, the present data demonstrate that beta(2)GPI gene expression is strictly related to the proliferative status of hepatic cells and that this protein could play a role in maintaining liver cells vitality when exposed to different stress factors such as regeneration after partial hepatectomy or growth factors depletion