[Show abstract][Hide abstract] ABSTRACT: Human peripheral blood leukocytes from healthy volunteers have been employed to investigate the induction of genotoxic effects following 2 h exposure to 900 MHz radiofrequency radiation. The GSM signal has been studied at specific absorption rates (SAR) of 0.3 and 1 W/kg. The exposures were carried out in a waveguide system under strictly controlled conditions of both dosimetry and temperature. The same temperature conditions (37.0 +/- 0.1 degrees C) were realized in a second waveguide, employed to perform sham exposures. The induction of DNA damage was evaluated in leukocytes by applying the alkaline single cell gel electrophoresis (SCGE)/comet assay, while structural chromosome aberrations and sister chromatid exchanges were evaluated in lymphocytes stimulated with phytohemagglutinin. Alterations in kinetics of cell proliferation were determined by calculating the mitotic index. Positive controls were also provided by using methyl methanesulfonate (MMS) for comet assay and mitomycin-C (MMC), for chromosome aberration, or sister chromatid exchange tests. No statistically significant differences were detected in exposed samples in comparison with sham exposed ones for all the parameters investigated. On the contrary, the positive controls gave a statistically significant increase in DNA damage in all cases, as expected. Thus the results obtained in our experimental conditions do not support the hypothesis that 900 MHz radiofrequency field exposure induces DNA damage in human peripheral blood leukocytes in this range of SAR.
Full-text · Article · Jun 2005 · Bioelectromagnetics
[Show abstract][Hide abstract] ABSTRACT: Chromosomal aberrations were investigated in 56 cattle with chronic enzootic haematuria (CEH) raised on pastures giving access to bracken fern. Of these animals, 27 were slaughtered and showed neoplastic lesions of the urinary bladder. Tumour tissue from 11 of the 27 cattle contained bovine papillomavirus type 2 (BPV-2) DNA. Increased numbers of chromosomal aberrations were seen in all animals with CEH, as compared with 30 control cattle that had had no access to bracken fern. The highest clastogenic effect was observed in cattle with urinary bladder cancer and evidence of BPV-2 DNA, suggesting that BPV-2 and bracken fern act synergistically in the production of chromosomal instability. In 19 of 20 animals with CEH, two bracken fern toxic compounds (quercitin and ptaquiloside) were demonstrated in urine, serum and milk.
No preview · Article · Aug 2004 · Journal of Comparative Pathology
[Show abstract][Hide abstract] ABSTRACT: Ochratoxin A (OTA) and zearalenone (ZEA), two naturally occurring contaminants of animal feed, have been implicated in several mycotoxicoses in farm livestock but there is little information on their genotoxicity and toxicity in these species. Therefore, we investigated on the cytogenetic and cytotoxic effects of both OTA and ZEA in in vitro cultures of bovine lymphocytes. We determined chromosome aberrations (CAs) and sister chromatid exchanges (SCEs) as well as the mitotic index (MI) and cell viability following OTA and ZEA treatment. This report is the first to provide evidence of a statistically significant increase of structural CAs and of SCEs/cell associated with a reduction of the MI in all OTA- and ZEA-treated bovine lymphocyte cultures and a clear reproducible reducing effect of OTA on cell viability mediated by enhanced apoptosis. OTA-induced programmed cell death was not limited to bovine lymphocytes, as comparable data were demonstrated in the human leukemic T-cell line Jurkat.
No preview · Article · Feb 2004 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: INTRODUCTION – Ochratoxin A (OTA) and zearalenone (ZEA) are fungal metabolites which con-taminate animal and human food. They have been found in cow's meat and milk and several reports indi-cated that OTA was immunosuppressive, carcinogenic and teratogenic in animals (Hussein and Brasel, 2001; Creppy, 2002). On the other hand, ZEA and its metabolites have estrogenic and anabolic activities, being able to cause alterations in the reproductive tract of laboratory animals (Creppy, 2002) and dairy cattle, and having negative effects on meiotic progression of bovine oocytes (Minervini et al, 2001). The mechanisms by which OTA and ZEA damage the cells are not completely understood; recent results evi-denced that OTA induces apoptosis in MDCK-C7 cells, in cultured human proximal tubule cells and in HeLa cells (Schwerdt et al, 1999). On the other hand, no data are available on the cytotoxic and on the apoptotic activity of OTA and ZEA in domestic animals and particularly in cattle, we therefore examined the induction of apoptosis in bovine lymphocytes exposed in vitro to increasing concentrations of both OTA and ZEA. MATERIAL AND METHODS – Lymphocyte cultures. Lymphocytes from 5 bovine subjects were sep-arated by Ficoll Hypaque gradient density. One ml of buffy coat was cultured in 9 ml of RPMI 1640 medi-um supplemented with 10% heat inactivated FBS, 10 µg/ml L-glutamine and 10 µg/ml Pokeweed mito-gen in a humidified atmosphere containing 5% CO 2 at 37 °C. Cell cultures were set up in the same exper-imental conditions and treated with increasing concentrations of OTA or ZEA, dissolved in DMSO and Ethanol respectively. In order to assess the possible induction of apoptosis following OTA and ZEA treat-ment, preliminary experiments were carried out for dose-response and time-response studies. Concentrations ranging from 0.5 to 4.0 µM and a time-exposure of 24 hs were chosen for best evidencing the apoptotic activity. The tested doses were next to the upper limits (µg/kg) of OTA and ZEA evidenced in cereals (Creppy, 2002).
Full-text · Article · Jan 2003 · Italian Journal of Animal Science
[Show abstract][Hide abstract] ABSTRACT: The genotoxic activity of the pesticides gliphosate, vinclozolin and DPX-E9636 was studied in in vitro cultures of bovine lymphocytes, using chromosome aberration (CA) and sister chromatid exchange (SCE) frequencies as genetic end-points and a variation of glucose 6-phosphate dehydrogenase (G6PD) enzyme activity as a marker of changes in the normal cell redox state. Results indicated a statistically significant increase of structural aberrations, sister chromatid exchanges and G6PD activity, suggesting that the pesticides tested induce either oxidative stress or a mutagenic effect in this species. The evaluation of both mitotic index and cell viability, after pesticide exposure, demonstrates a high cytotoxic effect which is always associated with the observed genotoxic effect.
Full-text · Article · Aug 1998 · Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis
[Show abstract][Hide abstract] ABSTRACT: We analyzed chromosome aberrations (CAs), sister chromatid exchanges (SCEs), mitotic index (MI), and glucose 6-phosphate dehydrogenase (G6PD) enzyme activity in human peripheral lymphocytes from three healthy donors exposed in vitro to different concentrations of gliphosate, vinclozolin, atrazine, and DPX-E9636. The pesticides gliphosate, vinclozolin, and atrazine have been studied in a broad range of genetic tests with predominantly conflicting or negative results, whereas little is known about the genotoxicity of DPX-E9636. In our experimental conditions, each chemical compound tested produced a dose-related increase in the percent of aberrant cells and an increase of SCE/cell. Furthermore, at the highest concentrations of vinclozolin, atrazine, and DPX-E9636, we observed a significant reduction of the mitotic index. The increase of G6PD activity in exposed lymphocyte cultures strongly indicated an induction of a pro-oxidant state of the cells as an initial response to pesticide exposure.
Full-text · Article · Feb 1998 · Environmental and Molecular Mutagenesis