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The Buccal Micronucleus Cytome Assay (BMCyt) has become an important biomonitoring tool for assessing cytogenetic damage in many studied populations. Each laboratory applies protocols that vary according to the method of collecting and preparing samples. Besides, Brazil is a country of great territorial extensions that received immigrants from various parts of the world with different genetic backgrounds. Therefore, the present study aimed to evaluate the inter-laboratory variation in scoring the same set of slides using the more comprehensive scoring criteria, to standardize the BMCyt protocol, to observe the basal alterations in populations of different Brazilian regions and to compare it with other places around the world. Our results showed that a valuable number of laboratories participated, ten laboratories from different regions of the country, for the validation of the BMCyt in human biomonitoring studies, resulting in the 804 healthy individuals. This was possible because we observed: a range of measures needs to be considered, such as the baseline frequency of DNA damage and cell death in non-exposed individuals; age when grouped showed an influence on DNA damage, although when evaluated by group we did not see an influence; association between smoking habit and all endpoints of the BMCyt (except karyolytic cells) was evident; the basal MN frequency, in the majority of groups, follows those around the world; and the BMCyt was confirmed as a good health status biomarker. We emphasize the need for constant discussions on the parameters of cell death due to greater difficulty among the analyzers.

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Nas últimas décadas, a qualidade da água do Rio do Peixe, localizado no interior do Estado de São Paulo, está diminuindo, principalmente porque o rio vem sofrendo com o desmatamento feito às suas margens, o que provocou o assoreamento e permitiu o despejo de todos os tipos de resíduos, em especial das indústrias que ficam ao seu redor. Assim, o objetivo deste trabalho foi avaliar o potencial citotóxico das águas do Rio do Peixe, coletadas em quatro propriedades rurais localizadas em Garça­SP (nascente), Tupã-SP, Flórida Paulista-SP e Ouro Verde-SP (jusante), usando como sistema teste vegetal as células meristemáticas de raiz de Allium cepa L. Os resultados obtidos mostraram que todas as amostras das águas coletadas não apresentaram efeito citotóxico após 24 horas de tratamento. Entretanto, as amostras obtidas em Tupã, Flórida Paulista e Ouro Verde (jusante) foram mutagênicas, pois causaram o aparecimento de alterações nas células, principalmente, dos tipos metáfases-colchicínicas, anáfases desorganizadas, multipolares e com ponte cromatídica, além de células micronucleadas. Portanto, os resultados obtidos alertam para o perigo eminente que os efluentes lançados indiscriminadamente no ambiente, de rios e lagos, podem representar não só aos organismos que ali habitam, mas a todos os outros que dele dependem, seja para lazer, limpeza, higiene ou alimentação.

(Cytotoxicity of waters of the River Peixe (São Paulo-Brazil), in meristematic root cells of Allium cepa L.) In recent decades, the water quality of the River Peixe, located within the State of São Paulo, has been decreasing, mainly because the river has suffered from deforestation made to its banks, causing silting and allowed the dumping of all types of waste, especially in industries that are around you. The objective of this study was to evaluate the cytotoxic potential of the waters of the River Peixe, collected at four farms located in Garça-SP (source), Tupã-SP, Flórida Paulista-SP and Ouro Verde-SP (downstream), using as a system test plant root meristematic cells of Allium cepa L. The results showed that all water samples collected was no cytotoxic effect after 24 hours of treatment. However, samples taken in Tupã, Flórida Paulista and Ouro Verde (downstream) were mutagenic, because it caused the appearance of changes in cells, mainly types of colchicine-metaphase, disorganized anaphase, multipolar and with chromatid bridge, addition of micronucleated cells. Therefore, the results warn of imminent danger that the effluents discharged indiscriminately into the environment may represent not only the organisms that live there, but for all others who depend on it, whether for leisure, cleaning, hygiene or food.

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Flunitrazepam (FNZ) is a sedative benzodiazepine prescribed for the short-term treatment of insomnia. However, there are concerns regarding possible carcinogenic or genotoxic effects of this medicine. Thus, the aim of this study was to evaluate the cytotoxic, clastogenic and aneugenic effects of FNZ in hepatoma cells from Rattus norvegicus (HTC) in vitro and in bone marrow cells of Wistar rats in vivo. These effects were examined in vitro following treatment with 0.2, 1.0, 5.0 or 10 μg/mL FNZ using a micronucleus test with a cytokinesis block or in vivo using a chromosomal aberration test following treatment with 7, 15 or 30 μg/mL/kg body weight. The results showed that the benzodiazepine concentrations tested were not cytotoxic, aneugenic or clastogenic. However, considering the adverse effects of using this benzodiazepine, more studies are required.

Flunitrazepam (FNZ) é um sedativo benzodiazepínico prescrito para o tratamento da insônia em curto prazo. Entretanto, existe a preocupação com relação aos possíveis efeitos carcinogênicos ou genotóxicos causados por este fármaco. Então, o objetivo deste estudo foi avaliar os efeitos citotóxicos, clastogênicos e aneugênicos do FNZ em células de hepatoma de Rattus norvegicus (HTC) in vitro e em células de medula óssea de ratos Wistar in vivo. Foram testadas as concentrações de 0,2, 1,0 e 10 μg/mL de FNZ pelo teste do micronúcleo com bloqueio de citocinese in vitro e 7, 15 e 30 μg/mL/kg de peso corpóreo para o teste de aberração cromossômica in vivo. Os resultados mostraram que as concentrações do benzodiazepínico testadas não foram citotóxicas, aneugênicas ou clastogênicas. Entretanto, considerando os efeitos adversos do uso deste benzodiazepínico, mais estudos são necessários.

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