995 resultados para Genetic toxicology


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Micronuclei and nuclear alterations tests were performed on erythrocytes of Oreochromis niloticus (Perciformes, Cichlidae) in order to evaluate the water quality from Paraiba do Sul river, in an area affected by effluents from an oil shale processing plant, located in the city of Sao Jose dos Campos, Brazil-SP. Water samples were collected on 2004 May and August (dry season) and on 2004 November and 2005 January (rain season), in three distinct sites, comprising 12 samples. It was possible to detect substances of clastogenic and/or aneugenic potential, as well as cytotoxic substances, chiefly at the point corresponding to the drainage of oil shale plant wastes along the river. The highest incidence of micronuclei and nuclear alterations was detected during May and August, whereas the results obtained in November and January were insignificant. This work shows that the effluent treatment provided by the oil shale plant was not fully efficient to minimize the effect of cytotoxic and mutagenic substances in the test organism surveyed. (c) 2006 Elsevier B.V. All rights reserved.

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In this study, micronucleus and nuclear alterations tests were performed on erythrocytes of Oreochromis niloticus (Perciformes, Cichlidae) in order to evaluate the water quality of the Atibaia river, in an area that receives effluents discharge of a petroleum refinery and also to evaluate the effectiveness of the treatments used by the refinery. Water samples were collected in five different sites related with a refinery from São Paulo State, Brazil. For the micronucleus and nuclear alterations tests, O. niloticus specimens were exposed for 72 h to the water samples and in pure ground water (negative control). The results herein obtained indicated that the treatments used by the refinery diminished the cytogenetic damage; however they were not fully effective, since the final mill has induced damages in the genetic material of the test organism. (C) 2008 Elsevier B.V. All rights reserved.

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In the present study, we applied Chromosome Aberration (CA) and Micronucleus (MN) tests to Allium cepa root cells, in order to evaluate the water quality of Guaeca river. This river, located in the city of Sao Sebastiao, SP, Brazil, had been affected by an oil pipeline leak. Chemical analyses of Total Petroleum Hydrocarbons (TPHs) and Polycyclic Aromatic Hydrocarbons (PAHs) were also carried out in water samples, collected in July 2005 (dry season) and February 2006 (rainy season) in 4 different river sites. The largest CA and MN incidence in the meristematic cells of A. cepa was observed after exposure to water sample collected during the dry season, at the spring of the river, where the oil leak has arisen. The F, cells from roots exposed to such sample (non-merismatic region) were also analyzed for the incidence of MN, showing a larger frequency of irregularities, indicating a possible development of CA into MN. Lastly, our study reveals a direct correlation between water chemical analyses (contamination by TPHs and PAHs) and both genotoxic and mutagenic effects observed in exposed A. cepa cells. (C) 2007 Elsevier B.V. All rights reserved.

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Studies of DNA damage in gastric epithelial cells of Helicobacter pylori (H. pylori)-infected patients are conflicting, possibly due to different methods used for scoring DNA damage by Comet assay. Therefore, we compared the sensitivity of visual microscopic analysis (arbitrary units-scores and comets%) and image analysis system (tail moment), in the gastric epithelial cells from the antrum and corpus of 122 H. pylori-infected and 32 non-infected patients. The feasibility of cryopreserved peripheral blood lymphocytes and whole-blood cells for DNA damage biomonitoring was also investigated. In the antrum, the levels of DNA damage were significantly higher in H. pylori-infected patients with gastritis than in non-infected patients with normal mucosa, when evaluated by image analysis system, arbitrary units and comets%. In the corpus, the comets% was not sufficiently sensitive to detect the difference between H. pylori-infected patients with gastritis and non-infected patients with normal mucosa. The image analysis system was sensitive enough to detect differences between non-infected patients and H. pylori-infected patients with mild gastritis and between infected patients with moderate and severe gastritis, in both antrum, and corpus, while arbitrary units and comets% were unable to detect these differences. In cryopreserved peripheral blood lymphocytes, the levels of DNA damage (tail moment) were significantly higher in H. pylori-infected patients with moderate and severe gastritis than in non-infected patients. Overall, our results indicate that the image analysis system is more sensitive and adequate to measure the levels of DNA damage in gastric epithelial cells than the other methods assayed. (c) 2005 Elsevier B.V. All rights reserved.

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This work shows the chemical characterization of a dye processing plant effluent that was contributing to the mutagenicity previously detected in the Cristais river, São Paulo, Brazil, that had an impact on the quality of the related drinking water. The mutagenic dyes Disperse Blue 373, Disperse Orange 37 and Disperse Violet 93, components of a Black Dye Commercial Product (BDCP) frequently used by the facility, were detected by thin layer chromatography (TLC). The blue and orange dyes were quantified by high performance liquid chromatography (HPLC/DAD) in a raw and treated effluent samples and their contribution to the mutagenicity was calculated based on the potency of each dye for the Salmonella YG1041. In the presence of S9 the Disperse Blue 373 accounted for 2.3% of the mutagenic activity of the raw and 71.5% of the treated effluent. In the absence of S9 the Disperse Blue 373 accounted for 1.3% of the mutagenic activity of the raw and 1.5% of the treated effluent. For the Disperse Orange 37, in the presence of S9, it contributed for 0.5% of the mutagenicity of the raw and 6% of the treated effluent. In the absence of S9; 11.5% and 4.4% of the raw and treated effluent mutagenicity, respectively. The contribution of the Disperse Violet 93 was not evaluated because this compound could not be quantified by HPLC/DAD. Mutagenic and/or carcinogenic aromatic amines were also preliminary detected using gas chromatograph/mass spectrometry in both raw and treated and are probably accounting for part of the observed mutagenicity. The effluent treatment applied by the industry does not seem to remove completely the multagenic compounds. The Salmomella/microsome assay coupled with TLC analysis seems to be an important tool to monitor the efficiency of azo dye processing plant effluent treatments. (c) 2006 Elsevier B.V. All rights reserved.

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Several studies have suggested that dietary supplementation with antioxidants can influence the response to chemotherapy as well as the development of adverse side effects that result from treatment with antineoplastic agents. The emphasis of the present study was to investigate whether the administration of a single dose of oral glutamine had any protective effect against cisplatin-induced clastogenicity. Cisplatin was administered to Wistar rats either alone or after treatment with glutamine. The rats were treated with glutamine (300 mg/kg b.w.) by gavage 24 h before the administration of cisplatin (5 mg/kg b.w., i.p.) and then sacrificed 24h after treatment with cisplatin. Glutamine significantly reduced (by about 48%) the clastogenicity of cisplatin in rat bone marrow cells. The antioxidant action of glutamine presumably modulates the clastogenic action of cisplatin. (C) 2002 Elsevier B.V. B.V. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The in vitro cytogenetic effects of the 43-kDa molecular mass exocellular glycoproteic component (GP 43) from Paracoccidioides brasiliensis were studied in cultures from human lymphocytes. The sample included 10 healthy, white, non-smoking, non-related males (mean age of 31.3 ± 8.2 years). Besides the control, three concentrations of GP 43 (0.125, 1.25 and 5 μg/ml) were used. In each group, around 1000 cells were examined in search of chromosome aberrations, and 30,000 metaphases were analysed for the determination of the Mitotic Index. The authors conclude that GP 43 most probably causes inhibition of the cell cycle and aneugenic and clastogenic effects.

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Fish blood erythrocytes are frequently used as sentinels in biomonitoring studies. Usually, fish blood is collected by painful cardiac or caudal vein punctures. Previous anesthesia could decrease animal suffering but it is not known at present whether anesthesia can cause confounding effects. Therefore, using the alkaline single cell gel (SCG)/comet assay with blood erythrocytes of the cichlid fish Nile tilapia, we tested for a possible modulation of induced DNA damage (methyl methanesulfonate; MMS) by the anesthetic benzocaine administered by bath exposure (80mg/l for ∼10min). Furthermore, benzocaine (80-600mg/l) was tested for its genotoxic potential on fish erythrocytes in vitro and for potential interactions with two known genotoxins (MMS and hydrogen peroxide). Our results did neither indicate a significant increase in the amount of DNA damage (even after a 48h follow-up), nor indicated interactions with MMS-induced DNA damage when fish were exposed to benzocaine in vivo. There was also no increase in DNA damage after in vitro exposure of fish erythrocytes to benzocaine. Clear concentration-related effects were observed for the two genotoxins in vitro, which were not significantly altered by the presence of benzocaine. These results suggest that anesthesia of fish does not confound comet assay results and the use of blood samples from anesthetized fish can be recommended with regard to animal welfare. © 2002 Elsevier Science B.V. All rights reserved.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)