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1
Pigorsch, Steffi Ulrike. "Untersuchungen zur Radiosensitivität mit dem Comet-Assay." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963220853.
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McArt, Darragh Gerrard. "Systematic quantitative analysis of the comet assay." Thesis, University of Ulster, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551559.
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The single cell gel electrophoresis assay (comet assay) has been widely used over the last 30 years. It is a robust method of estimating DNA movement under perturbation. In the assay cells are embedded in agarose on a frosted slide. The amount of broken or fragmented DNA that is removed from the central body, after the cell has been lysed and electrophoresed, is estimated as the total volume of DNA damage in the form of strand breaks caused by the insult. The damage is quantified by fluorescence microscopy with analysis software. It is a simple technique that is efficient and relatively quick. With the comet methodology there is much debate on the underlying mechanisms of cellular damage and repair and over how strongly the comet shape reflects the DNA damage that has occurred. It is often used as a quick-fire detection method to back up other analysis methods with very little thought given to the information it provides. The technique itself is open to experimenter bias at the microscopy level, where researchers have the freedom to select which comets to analyse. Addressing these issues along with those of standardising the technique and developing novel methods of comet analysis may enhance the information it provides. Using statistical and computational methods, it is proposed that a simulation of the comet would provide important information about DNA damage at a cellular level while offering impartial judgement and reproducibility. Information is available on some aspects of comet structure in published literature and with new techniques both computationally and experimentally it has become possible to examine intrinsic information on comet structure. Information was also established via novel and existing laboratory techniques and also through microscopy techniques to examine architecture. A computational modelling and simulation approach can then be used to ask important biological questions on aspects of DNA damage and repair at a cellular level.
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Schmid, Oliver. "Untersuchungen zur Genotoxizität von Formaldehyd in vitro und in vivo." [S.l. : s.n.], 2009. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-66943.
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Menke, Merten. "Molekulare Grundlagen und Anwendungsmöglichkeiten des Comet Assay in Pflanzen." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963172751.
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Hoffmann, Heike. "Der Comet Assay als Test im Biomonitoring - Untersuchungen zum Nachweis genotoxischer Effekte des Rauchens." [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-56705.
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Paiva, Jean Carlos Gomes. "Biomonitoramento GenÃtico de Agricultores expostos a Pesticidas nos MunicÃpios de Tianguà e Ubajabra CearÃ." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=7093.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoNos Ãltimos anos, o uso de pesticidas na agricultura tem aumentado e associaÃÃes entre a exposiÃÃo a produtos quÃmicos agrÃcolas e danos ao DNA e cÃncer tem sido relatados. O Brasil à um dos lÃderes mundiais na utilizaÃÃo de pesticidas, no entanto, estudos que avaliem o impacto da exposiÃÃo ocupacional a pesticidas sobre a incidÃncia e mortalidade por cÃncer ainda sÃo escassos na populaÃÃo brasileira. O teste do cometa alcalino e a anÃlise de aberraÃÃes cromossÃmicas (AC) foram utilizados para avaliar danos primÃrios ao DNA em linfÃcitos do sangue perifÃrico de trabalhadores expostos a uma mistura complexa de pesticidas em duas pequenas comunidades rurais nos municÃpios de Tianguà e Ubajara, localizados no oeste do Estado do Cearà (Nordeste do Brasil). Estes MunicÃpios estÃo entre as maiores Ãreas agrÃcolas do Estado. O teste do cometa mostrou que o Ãndice e freqÃÃncia de danos observados nos grupos expostos foram significativamente maiores em relaÃÃo aos grupos controle (P <0,05). Por outro lado, nÃo foram detectadas diferenÃas significativas em relaÃÃo a AC estruturais e numÃricas nas comunidades avaliadas. AlÃm disso, os nÃveis observados de quebras da fita de DNA e freqÃÃncias de AC, estratificadas por tempo de exposiÃÃo, nÃo foram estatisticamente diferentes nos agricultores de ambas comunidades rurais. Os resultados sugerem que os danos causados por pesticidas na Ãrea de estudo nÃo foram significativos o suficiente para induzir mutaÃÃes permanentes ou interferir na formaÃÃo do aparelho mitÃtico. Danos mÃnimos causados pelos pesticidas podem ter sido submetidos a reparo celular, explicando a ausÃncia de AC estruturais e numÃricas. As anÃlises da Ãgua do reservatÃrio que serve de fonte para irrigaÃÃo das plantaÃÃes e abastece os municÃpios da regiÃo nÃo detectou contaminaÃÃo por resÃduos de pesticidas.
In recent years, the use of pesticides in agriculture has been steadily increasing, and associations between exposure to agricultural chemicals and DNA damage and cancer have been reported. Brazil is one of the world leaders in pesticide use; however, studies that evaluate the impact of pesticide exposure on cancer incidence and mortality are very scarce in the Brazilian population. The alkaline comet assay and the chromosome aberration (CA) test were used to evaluate primary DNA damage in the peripheral blood lymphocytes of workers exposed to a complex mixture of pesticides in two small rural communities in the municipalities of Tianguà and Ubajara, located in the western part of Cearà State (Northeast Brazil), which are among the largest agricultural areas of the state. The comet assay showed that the damage index and damage frequency observed in the exposed groups were significantly higher in relation to the controls (P < 0.05). On the other hand, no differences were detected regarding structural and numerical CAs in the communities evaluated. Additionally, the observed levels of DNA strand breaks and frequencies of CAs, stratified for exposure time, were not statistically different for individuals of either rural community. Our results suggest that the damages caused by pesticides in our study area were not great enough to induce permanent mutations or to interfere with mitotic apparatus formation; minimal pesticide damages could have undergone cellular repair, explaining the absence of structural and numerical CAs. Analyses of water from the reservoir that serves as a source for irrigation of crops and supplies the cities of the region did not detect contamination by pesticides.
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DUARTE, RENATO C. "Teste do cometa como ferramenta de controle da cadeia do frio." reponame:Repositório Institucional do IPEN, 2009. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9435.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Leyk, Williams Malgorzata. "Summarizing FLARE assay images in colon carcinogenesis." Texas A&M University, 2004. http://hdl.handle.net/1969.1/3132.
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Intestinal tract cancer is one of the more common cancers in the United States. While in some individuals a genetic component causes the cancer, the rate of cancer in the remainder of the population is believed to be affected by diet. Since cancer usually develops slowly, the amount of oxidative damage to DNA can be used as a cancer biomarker. This dissertation examines effective ways of analyzing FLARE assay data, which quantifies oxidative damage. The statistical methods will be implemented on data from a FLARE assay experiment, which examines cells from the duodenum and the colon to see if there is a difference in the risk of cancer due to corn or fish oil diets. Treatments of the oxidizing agent dextran sodium sulfate (DSS), DSS with a recovery period, as well as a control will also be used.
Previous methods presented in the literature examined the FLARE data by summarizing the DNA damage of each cell with a single number, such as the relative tail moment (RTM). Variable skewness is proposed as an alternative measure, and shown to be as effective as the RTM in detecting diet and treatment differences in the standard analysis. The RTM and skewness data is then analyzed using a hierarchical model, with both the skewness and RTM showing diet/treatment differences. Simulated data for this model is also considered, and shows that a Bayes Factor (BF) for higher dimensional models does not follow guidelines presented by Kass and Raftery (1995).
It is hypothesized that more information is obtained by describing the DNA damage functions, instead of summarizing them with a single number. From each function, seven points are picked. First, they are modeled independently, and only diet effects are found. However, when the correlation between points at the cell and rat level is modeled, much stronger diet and treatment differences are shown both in the colon and the duodenum than for any of the previous methods. These results are also easier to interpret and represent graphically, showing that the latter is an effective method of analyzing the FLARE data.
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Garcia, Juliana Maia Rabêlo Nucci. "Adaptação de Ensaio Cometa às células meristemáticas provenientes de raízes de propágulos de Rhizophora mangle para avaliar a genotoxicidade no ambiente marinho." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/21/21134/tde-24022017-142221/.
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O presente estudo teve como objetivo o estabelecimento de um método citogenotoxico, o ensaio cometa, adaptado às células meristemáticas provenientes de raízes de propágulos de mangue da espécie Rhizophora mangle para utilização em estudos sobre genotoxicidade em ambientes marinhos. Foram testados dois tipos de germinação de raízes, quatro diferentes soluções de extração de núcleos, duas soluções de lise e o não uso da lise, dois períodos de exposição à lise, dois períodos de relaxamento, dois períodos de eletroforese e a interação de duas condições de lise com dois diferentes tempos de relaxamento. A validação de método foi realizada através da exposição de núcleos a quatro diferentes concentrações de peróxido de hidrogênio. Os resultados mostraram que é possível a obtenção de cometas com núcleos extraídos de propágulos de Rhizophora mangle e que a validação de método apresenta uma relação concentração dependente entre o índice de dano de núcleos e a concentração do agente genotoxico testado. Os melhores parâmetros utilizados para obtenção de cometas através do método por nós adaptado são: PBS ou solução salina 12‰ como solução de extração, exposição à lise alcalina iônica por 60 minutos, 5 minutos de relaxamento e eletroforese em tampão pH>13, 0,8V/cm, 230mA por 20 minutos a 4ºC.This study aimed to establish a citogenotoxic method, the comet assay, adapted to the meristematic cells from propagule roots of red mangrove, Rhizophora mangle, for use in studies of genotoxicity in marine environments. Experiments were carried out to test two ways of root germination, four different nuclei extraction solutions, two lysis solutions and without lysis, two periods of exposure to lysis, two periods of unwinding, two periods of electrophoresis and the interaction of two lysis conditions with two different times of unwinding. Experiments on validation of the method were performed by exposing the nuclei to four different concentrations of hydrogen peroxide. The results showed that it is possible to obtain comets with nuclei extracted from the root of propagules of Rhizophora mangle and the validation data showed a dose-dependent relationship between the damage index and the concentration of the genotoxic agent tested. The best parameters to obtain comets using the method adapted by us are: PBS or saline 12‰ as extraction solution, exposure to alkaline lysis for 60 minutes, 5 minutes of unwinding and electrophoresis in buffer pH> 13, 0,8V/cm, 230mA for 20 min at 4ºC.
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Paiva, Jean Carlos Gomes. "Biomonitoramento Genético de Agricultores expostos a Pesticidas nos Municípios de Tianguá e Ubajabra Ceará." reponame:Repositório Institucional da UFC, 2011. http://www.repositorio.ufc.br/handle/riufc/16960.
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PAIVA, Jean Carlos Gomes. Biomonitoring genetic of farmers exposed to pesticides in the municipalities of Tiangua and Ubajara (Ceará, Brazil). 2011. 111 f. : Tese (doutorado) - Universidade Federal do Ceará, Programa de Pós-Graduação em Biotecnologia, Renorbio - Rede Nordeste de Biotecnologia. 2011.Submitted by demia Maia (demiamlm@gmail.com) on 2016-05-23T17:19:06Z No. of bitstreams: 1 2011_tese_jcgpaiva.pdf: 2591728 bytes, checksum: 4776344bdee5aac282c66c0a37608507 (MD5)
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Trindade, Fernanda Rocha da. "Avaliação do índice de dano celular em pacientes diagnosticadas com câncer de mama em tratamento com radioterapia através das técnicas de micronúcleo e ensaio cometa." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/56678.
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Introdução: Toda a exposição à radiação ionizante envolve um benefício e um risco inerente. O tratamento com radioterapia utiliza feixes de alta energia que tem como finalidade destruir o tumor, atingindo também áreas adjacentes e podendo causar dano celular, não visível macroscopicamente. Objetivos: O objetivo principal deste projeto é avaliar o índice de dano em células nucleadas do sangue periférico de pacientes diagnosticadas com câncer de mama em tratamento com radioterapia, através das técnicas de micronúcleo e ensaio cometa. O objetivo específico é avaliar a percepção de risco e coerção de pacientes diagnosticadas com câncer de mama em relação ao seu tratamento com radioterapia. Métodos: A metodologia consiste em dois sub-estudos, um com delineamento longitudinal, do tipo estudo de casos incidentes, composto por pacientes com câncer de mama em tratamento no Serviço de Radioterapia. Foram realizadas quatro coletas de sangue em diferentes momentos para a realização das duas técnicas: (1) antes do início do tratamento, (2) na segunda semana, (3) no final e (4) aproximadamente um mês após o seu término. O segundo sub-estudo, com delineamento transversal, foi realizado no período antes do tratamento radioterápico. As pacientes que foram submetidas à radioterapia foram pareadas com outro grupo de participantes voluntárias que não têm diagnóstico de câncer e nem indicação de radioterapia. Cada sub-estudo foi formado por 18 indivíduos do sexo feminino, totalizando 36 sujeitos de pesquisa. Utilizando-se a técnica de micronúcleo, foram analisadas três tipos de alterações celulares: micronúcleo, buds e pontes nucleoplasmáticas. Durante a segunda coleta de sangue um questionário contendo a percepção de coerção e de risco foi aplicado às pacientes. Resultados: Em relação ao estudo longitudinal houve diferença significativa na alteração nuclear de micronúcleo entre as coletas realizadas antes e após um mês de tratamento com radioterapia. Em relação à alteração nuclear buds não houve diferença significativa e em relação à alteração nuclear pontes nucleoplasmáticas houve diferença significativa, mas não foi possível verificar entre quais momentos da coleta de sangue. Houve diferença significativa na técnica ensaio cometa comparando as coletas realizadas duas semanas após o início da radioterapia e no final da mesma. Em relação ao estudo transversal, os resultados da técnica de micronúcleo mostraram que não há diferença significativa entre as pacientes com câncer e sem câncer. A percepção de coerção obteve um valor médio de 0,79, com desvio padrão de 0,91. Quanto à percepção de risco em relação ao seu tratamento, as pacientes inferiram um risco médio de 5,4% e um desvio padrão de 11,9%. A maioria das pacientes, 84% da amostra, teve uma percepção de risco que não ultrapassou 10%. Conclusão: A radioterapia induziu danos celulares, ou seja, houve efeito biológico causado pelo tratamento com radioterapia evidenciado pela alteração nuclear de micronúcleo. A técnica ensaio cometa evidenciou, que o sistema de reparo foi eficiente, pois, o dano celular induzido na segunda semana de tratamento diminuiu no final do mesmo. Com base na avaliação das percepções de coerção e de risco, em relação à radioterapia, foi possível verificar que: a) A percepção de risco obteve valores baixos, sendo que na maioria da amostra o risco percebido foi igual a zero; b) A baixa percepção de coerção evidencia que as pacientes tiveram liberdade para optar pelo tratamento proposto pela equipe assistencial com reduzida pressão de fatores externos.Background: Benefits and inherent risks are involved in any exposure to ionizing radiation. Treatment with radiation therapy uses high energy beams that aim to destroy the tumor, affecting also adjacent areas and potentially causing cell damage, in a macroscopic view. Objective: The main objective of this research was to evaluate the damage index in nucleated cells from peripheral blood of breast cancer patients receiving treatment with radiotherapy through the techniques micronucleus and comet assay. The specific objective is to evaluate the risk perception and coercion of patients diagnosed with breast cancer about their treatment with radiotherapy. Methods: The methodology consists of two sub-studies, the first one is a longitudinal study of incident cases, comprising patients with breast cancer undergoing treatment at the Radiotherapy Service. Four blood samples were taken at different times to the achievement of both techniques: (1) before starting treatment, (2) in the second week, (3) at the end and (4) a month after finished the treatment. The second sub-study, with cross-sectional design was carried out before radiotherapy. The patients who underwent radiotherapy were paired with another group of voluntary participants who have no diagnosis of cancer and are not using any radiation. Each sub-study consisted of 18 females, making 36 research subjects. Using the micronucleus assay, we analyzed three types of cellular changes: micronuclei, buds and nucleoplasmatic bridges. During the second blood collection a perception of coercion and risk perception questionnaire was applied to patients. Results: The longitudinal study showed a significant difference in the nuclear micronuclei changes between samples taken before and after a month of radiotherapy. Regarding amendment nuclear buds there was no significant difference and in relation to amendment nuclear nucleoplasmatic bridges there was a significant difference, but it was not possible to verify what time between blood collection. There were significant differences in the comet assay comparing the samples taken two weeks after the start of radiotherapy and at the end of treatment. Regarding the cross-sectional study, the micronucleus assay results showed no significant difference between patients with cancer and without cancer. The perception of coercion obtained an average value of 0.79 with a standard deviation of 0.91. Regarding the risk perception in relation to their treatment, patients inferred an average risk of 5.4% and a standard deviation of 11.9%. Most patients, 84% of the sample had a risk perception that did not exceed 10%. Conclusion: The radiation induced cell damage, there was biological effect caused by radiotherapy and evidenced by changes in nuclear micronuclei. The comet assay showed that the repair system was efficient, because cellular damage in the second week of treatment decreased at the end of it. Based on the assessment of the perceptions of coercion and risk in relation to radiotherapy, we found that: a) risk perception obtained low values, and in most of the sample perceived risk was zero, b) Low perception of coercion shows that the patients were free to choose the treatment proposed by the treatment team with a reduced pressure of external factors.
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Walsh, Ian Kinsella. "An evaluation of the chemosensitivity of superficial bladder cancer using the comet assay." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263376.
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ARAUJO, MICHEL M. "Aplicação do método microbiológico DEFT/APC e do teste do cometa na detecção do tratamento com radiação ionizante de hortaliças minimamente processadas." reponame:Repositório Institucional do IPEN, 2008. http://repositorio.ipen.br:8080/xmlui/handle/123456789/11658.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN/CNEN-SP
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Munoz, Daniel. "The Effects of Fruit and Vegetable Extracts on Surrogate Endpoint Biomarkers in Curatively Treated Head and Neck Squamous Cell Carcinoma Patients." Scholarly Repository, 2009. http://scholarlyrepository.miami.edu/oa_theses/186.
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Dietary factors have been implicated in the risk of head and neck squamous cell carcinoma (HNSCC). Much interest has been placed upon the effects of suspected chemopreventative agents found in fruit and vegetables associated with low HNSCC risk. However, studies investigating specific uptake of these agents have failed to show positive results. The possibility exists that single chemopreventative agents fail to provide the same beneficial effect as the various compounds found in a fruits and vegetables is examined. Curatively treated head and neck squamous cell carcinoma patients ingested Juice Plus, a F&V extract supplement containing multiple chemopreventative agents, for 12 weeks. Lymphocyte samples of participants were collect pre- and post- treatment and examined in pairs. Despite the study currently still blinded, surrogate endpoint biomarkers were evaluated to observer any modification between pre- and post treatment samples. Although a paired t-test showed no significant difference between pre- and post treatment samples on surrogate endpoint biomarkers, there is a significant difference in population distribution between treatment times signifying a modification of the surrogate endpoint biomarkers. The exact nature of this difference is pending due to the blinded status of the study.
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Trenz, Kristina. "Charakterisierung der Mutagensensitivität von Lymphozyten und lymphoblastoiden Zelllinien mit BRCA-Mutationen." [S.l.] : Universität Ulm , Medizinische Fakultät, 2003. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB10913295.
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Souza, Tiago Alves Jorge de. "Efeito do tamanho das nanopartículas de prata na indução de danos citotóxicos e genotóxicos nas linhagens celulares CHO-K1 e CHO-XRS5." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/17/17135/tde-29082013-164834/.
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Devido às características especiais as nanopartículas (10-9m) estão sendo utilizadas em uma ampla gama de produtos, porém é conhecido que a utilização dessas partículas podem causar efeitos biológicos adversos, aumentando a preocupação em relação à saúde e ao meio ambiente. Recentemente, as nanopartículas de prata (AgNPs) têm sido alvo de estudos genotóxicos e citotóxicos, sendo que ainda não existe um consenso acerca da relação entre tamanho e toxicidade dessas partículas. Assim, este trabalho avaliou a citotoxicidade e a genotoxicidade das AgNPs de 10 e 100 nm nas linhagens celulares CHO-K1 e CHO-XRS5, por meio do Ensaios de Viabilidade Celular, Sobrevivência Clonogênica, Teste do Micronúcleo, o Ensaio Cometa e Cinética do Ciclo Celular por Citometria de Fluxo. Em todos os ensaios, as células foram expostas por 24 h à diferentes concentrações de AgNPs (0,025 a 5,0 g/ml) e, as células não tratadas foram utilizadas como controle negativo. A concentração de 5,0 g/ml foi citotóxica nos ensaios de Viabilidade Celular e Sobrevivência Clonogênica, sendo excluída dos ensaios de genotoxicidade. De maneira geral, as células CHO-XRS5 apresentaram menor viabilidade e maior quantidade de danos no DNA do que as células CHO-K1. As AgNPs de 10 nm causaram maiores níveis de danos no DNA em ambas as linhagens e um aumento de células em subG1 logo após o tratamento na linhagem CHO-K1. Entretanto, no tempos 24 e 72 h após o tratamento foi verificada a maior toxicidade (células em subG1) das AgNPs de 100 nm quando comparadas com suas homólogas menores (10 nm). Assim, foi observado que as AgNPs de 10 nm apresentam efeito tóxico a curto prazo similar ou maior do que a mesma concentração de partículas de 100 nm. No entanto, os efeitos genotóxicos e citotóxicos de longo prazo das AgNPs de 100 nm foram maiores do que os da partículas de 10 nm para ambas as linhagens celulares, comprovando que a exposição às AgNPs maiores (100 nm) pode causar mais efeitos biológicos adversos do que suas homólogas menores (10 nm).Due to their particular characteristics, nanoparticles (10-9m) are being used in a range of products. However, these particles can cause adverse biological effects and because of that, there is a great concern about the health and environmental risks related to the use of these particles. Recently, silver nanoparticles (AgNPs) have been used in a variety of cytotoxicity and genotoxicity studies, but there are still controversies regarding the association between the size and the toxicity of these particles. Thus, in this study, we aimed to evaluate the cytotoxicity and genotoxicity of AgNPS (10 and 100 nm) in two different cell lines, CHO-K1 and CHO-XRS5, by performing Cell Viability assay (XTT), Clonogenic assay, Micronucleus test, Comet assay, as well as by investigating the Cell Cycle kinetics using the flow cytometry. For all the different assays, the cell cultures were exposed for 24 hours to different concentrations of AgNPs (0.025 to 5.0 g/ml) and the untreated cells were used as the negative controls. Since results from the Viability and Clonogenic assays indicated that the concentration of 5.0 g/ml was cytotoxic for both cell lines, this concentration was not included in the genotoxic assays. Our results indicated that the CHO-XRS5 cells presented a lower viability and higher levels of DNA damage compared to the CHO-K1 cells. The 10 nm-AgNPs induced greater levels of DNA damage than the 100 nm-particles in both cell lines and the former also led to a subG1 arrest soon after the treatment only in the CHO-K1 cell line. In contrast, results from all the other assays indicated that greater levels of toxicity were induced by the 100 nm-AgNPs when compared to the 10 nm-particles, both 24 and 72 h after the treatment. Thus, at the same concentration, the short-term effects of the 10 nm-AgNPs were equal to or more toxic than those of the 100 nm-particles. Nevertheless, both long-term genotoxicity and cytotoxicity induced by the 100 nm-AgNPs were greater than those induced by the 10 nm-particles for both cell lines, which suggests that the exposure to greater size particles (100 nm) can cause more adverse biological effects than the exposure to the smaller particles(10 nm).
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Noak, Natalia [Verfasser]. "Untersuchung von zytotoxischen und DNA-schädigenden Effekten durch Zementstäube auf kultivierte humane Lungenzellen : WST-1 Assay und COMET-Assay / Natalia Noak." Gießen : Universitätsbibliothek, 2013. http://d-nb.info/1064991084/34.
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Nerlich, Kai. "Untersuchung des genetischen Schadens in peripheren Lymphozyten von Dialysepatienten mittels Mikrokerntest und Comet-Assay." Doctoral thesis, [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=972069658.
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Huysamen, Cristal. "Diversity in the applications of the single cell gel electrophoresis (comet) assay / Cristal Huysamen." Thesis, North-West University, 2005. http://hdl.handle.net/10394/586.
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The development of the single cell gel electrophoresis assay (Comet assay) as a
powerful method for measuring DNA strand breakage and repair, has lead to a
broader understanding of the impact of certain internal and external factors on
DNA damage. This study describes the establishment of the Comet assay in our
laboratory and its application in a diversity of studies. These studies include the
monitoring of the effect of exercise on DNA damage and repair with the purpose
of establishing the optimal exercise program for middle aged men; in the analysis
of DNA repair in a breast cancer patient after chemotherapy, we demonstrated
that to get a really informative picture of baseline DNA damage, it is necessary to
invoke some type of insult to the DNA; we also studied the antioxidant activity of
plant extract and finally an industrial application of the Comet assay where we
studied DNA damage and repair in the lymphocytes of people exposed to a
variety of chemicals. The Comet assay was made even more informative by
incorporating additional steps by digesting the DNA on the microscope slides
with enzymes that recognize particular kinds of damage to the nucleic acid
(formamidopyrimidine DNA glycosylase (Fpg) and Endonuclease Ill (Endo Ill).
From these applications we can safely conclude that we have established the
Comet assay as reproducible assay with proven diversity in its applications.
The most significant contribution of this study is the quite novel modification of
the Comet assay to monitor the methylation status of DNA. In this we applied the
restriction endonuclease enzymes, Hpa ll and Msp I, which have different
sensitivities to methylation of their common target site. Changes in the
methylation levels of DNA after treatment of animals and isolated cells with
chemicals with known effects on DNA, were convincingly demonstrated and
indications of cell specificity in DNA methylation were observed. We believe that
this modification opens a new field of applications for the Comet assay.Thesis (M.Sc. (Biochemistry))--North-West University, Potchefstroom Campus, 2005.
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Barros, Tamiris Trevisan de. "Ingestão alimentar, perfil vitamínico e dano de DNA em crianças e adolescentes do município de Ribeirão Preto." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/17/17144/tde-26042018-134258/.
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O objetivo deste estudo é descrever o dano de DNA através das variáveis Tail Moment e Tail Intensity e investigar a associação entre o dano do DNA, padrão alimentar e concentrações plasmáticas de vitaminas em crianças e adolescentes em Ribeirão Preto (São Paulo, Brasil). Estudantes de 9 a 13 anos foram selecionados de três escolas de Ribeirão Preto (São Paulo, Brasil), totalizando uma amostra de 120 indivíduos. A coleta de dados incluiu antropometria, composição corporal, avaliação da ingestão utilizando um questionário de frequência alimentar (QFA) e o Índice de Qualidade da Dieta Revisado (IQD-R) e coleta de sangue para a dosagem de vitaminas e determinação do dano do DNA pelo método de eletroforese em gel de célula única - comet assay. Os indivíduos foram divididos em dois grupos opostos de dano do DNA usando duas técnicas distintas: análise de k-cluster e classificação por escala de dano. Padrões de ingestão de nutrientes também foram gerados, utilizando robust sparse k-means cluster, e associados com o dano de DNA. Para análise utilizaram-se os testes T de Student, Mann-Whitney e ANCOVA. Na primeira análise, o cluster 1 (n = 73), com menor dano de DNA, apresentou maior consumo de vegetais verdes escuros e alaranjados (p = 0,047), vegetais totais (p = 0,041) e carnes, ovos e leguminosas (p = 0,022), através do IQD-R, e um escore de IQD total maior (p = 0,030), indicando melhor qualidade de dieta em comparação ao cluster 2 (n = 47), de maior dano de DNA. O cluster 2 apresentou maior consumo de laticínios, em comparação ao cluster 1 (p = 0,008). Em relação a vitaminas plasmáticas, o cluster 1 apresentou maior concentração de riboflavina (p = 0,004). No segundo método de divisão, o grupo 1 (n = 108), com menor dano de DNA, apresentou maior concentração de retinol (p = 0,010), beta-caroteno (p = 0,017) e riboflavina (p = 0,046), após teste de ANCOVA ajustado para o índice de massa corporal (IMC) em comparação ao grupo 2 (n = 12). Na divisão por padrão alimentar, o cluster 2 (n = 58), com menor consumo de aminoácidos e micronutrientes, apresentou maior consumo de energia (p = 0,001) e uma tendência de maior dano do DNA (p = 0,063) em relação ao cluster 1 (n = 27), com maior ingestão de nutrientes. Estes achados corroboram a literatura, afirmando o papel protetor de vitaminas e antioxidantes contra o dano do DNA.The aim of this study is to describe the DNA damage using values of Tail Moment and Tail Intensity and investigate the association between DNA damage, dietary pattern and vitamin status in children and adolescents in Ribeirão Preto (São Paulo, Brazil). 9 to 13 year old students were selected from three schools in the city of Ribeirão Preto (São Paulo, Brazil), totalizing a sample of 120 subjects. Data collection included anthropometry, body composition, assessment of food intake using a food frequency questionnaire (FFQ), quality of diet through Revised Health Eating Index (HEI-R), and blood sampling for vitamins dosage and determination of DNA damage with single cell gel electrophoresis - comet assay. The subjects were divided into two opposing groups according to DNA damage using two different methods: k-cluster analysis and classification by scale of damage. Nutrients intake patterns were also generated through robust sparse k-means cluster and associated with DNA damage. The statistical analysis were performed using Student\'s T test, Mann-Whitney test and ANCOVA. In the first analysis, cluster 1 (n = 73), with less DNA damage presented higher intake of dark green and orange vegetables (p = 0,047), total vegetables (p = 0,041), meat, eggs and legumes (p = 0,022), assessed through HEI, as well as a higher total HEI-R level (p = 0,030), indicating higher quality of diet compared to cluster 2 (n = 47), with increased DNA damage. Cluster 2 presented a higher intake of milk and dairy products, compared to cluster 1 (p = 0,008). In relation to vitamins plasma levels, cluster 1 presented higher levels of riboflavin (p = 0,004). In the second method of division, group 1 (n = 108), with less DNA damage, presented higher levels of retinol (p = 0,010), beta-carotene (p = 0,017) and riboflavin (p = 0,046), after ANCOVA teste adjusted for body mass index (BMI) compared to group 2 (n = 12). In the division by dietary pattern, cluster 2 (n = 58) with a lower consumption of amino acids and micronutrients had higher energy intake (p = 0,001) and a tendency of higher DNA damage (p = 0,063) compared to cluster 1(n = 27), with higher intake of nutrients. These findings corroborate the literature, asserting protective role of vitamins and antioxidants against DNA damage.
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Kahmann, Cindy. "Quantifizierung von DNA-Schäden an adhaerenten Zelllinien nach Bestrahlung mit 188 Re- bzw. Röntgenstrahlung unter Zugabe von Methimazol, Nicotinamid und Perchlorat durch den Comet Assay." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1219154119996-02487.
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Gröger, Michael. "Einfluss einer Beatmung mit 100% Sauerstoff auf die Ausbildung von DNA-Strangbrüchen und die Parameter des oxidativen Stress im Langzeitmodell des septischen Schocks beim Schwein." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-63634.
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SOUZA, Talita Giselly dos Santos. "Avaliação genotóxica in vivo dos efeitos agudos da mistura dos praguicidas metomil e cipermetrina." Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/18344.
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CAPES
Os agrotóxicos foram utilizados primeiramente na saúde pública, a fim de combater vetores que causam doenças. Posteriormente seu uso tornou-se intensivo na agricultura, com intenção de melhorar a produção e a aparência dos produtos. Atualmente o Brasil é o maior consumidor de defensivos agrícolas do mundo, e isto é um fato preocupante, visto que a exposição a esses agentes tóxicos pode trazer sérios riscos à saúde humana e meio ambiente. A Cipermetrina (Cp) e Metomil (Mt) são agrotóxicos largamente utilizados na agricultura brasileira. Conquanto a Agência Nacional de Vigilância Sanitária (ANVISA) tenha estabelecido a Ingestão Diária Aceitável (IDA) de ambos isoladamente, é sabido que o consumidor está exposto a misturas de praguicidas por meio de sua dieta. No entanto, a maioria das pesquisas estudam os efeitos dos agrotóxicos isoladamente, sendo limitado o número de trabalhos que analisam as combinações desses compostos. Diante disso, avaliamos o potencial genotóxico, pelo ensaio cometa, e mutagênico, pelo teste do micronúcleo, de misturas de formulações comerciais de Mt e Cp em doses baixas. Setenta camundongos foram distribuídos em sete grupos. O grupo controle negativo (CN) recebeu água destilada (veículo de diluição). O controle positivo (CP) recebeu ciclofosfamida (20 mg/kg). Três grupos receberam misturas: A (0,05mg Mt + 0,0625 mg Cp), B (0,005mg Mt + 0,0125mg Cp) e C (0,0005mg Mt + 0,00125mg Cp). O grupo D recebeu apenas Mt (0,05mg) e o E apenas Cp (0,0625 mg). Os resultados de cada grupo foram comparados entre si pelo teste de Kruskal-Wallis com análise a posteriori, usando a estratégia de testes t par-a-par com correção de Bonferroni (p< 0,05). Todas as misturas apresentaram efeito genotóxico e apenas a mistura na maior concentração (A) foi mutagênica. Quando isolados, apenas a Cp apresentou atividade genotóxica significativa; entretanto, a média do dano de E foi menor que a encontrada nas três misturas estudadas. Desta forma, conclui-se que os efeitos do Mt e Cp são potencializados quando estes estão associados, mesmo em doses baixas, podendo causar danos à saúde.
Pesticides were firstly used in public health in order to tackle disease vectors. Afterwards,in order to improve agricultural production and products good appearance,their use in crops became intensive. Currently, Brazil is the largest consumer of pesticides in the world; the exposure to these toxic agents can pose serious risks to human health and to the environment. Cypermethrin (Cp) and Methomyl (Mt) are pesticides widely used in Brazilian agriculture. While the National Health Surveillance Agency (ANVISA) has established their Acceptable Daily Intake (ADI), consumers are exposed to mixtures of pesticides through food. Nonetheless, most of studies consider the effects of isolated pesticides, when few studies analyze the combinations of compounds. Here, we evaluated the genotoxic and mutagenic effects of low doses of Mt and Cp mixtures obtained from commercial formulations. To do that, seventy mice, divided in seven groups,were used to perform comet assay and micronucleus test. The negative control group received distilled water (dilution vehicle of pesticides),while positive control group received cyclophosphamide (20 mg / kg). Three groups received mixtures of Mt and Cp: A (0.05 mg Mt + 0.0625 mg Cp), B (0.005 mg Mt + 0,0125mg Cp) and C (0,0005mg Mt + 0,00125mg Cp). The D group received only Mt (0.05 mg) and E group received only Cp (0.0625 mg). Kruskal-Wallis test was performed for statistical analysis; subsequently, a multiple comparison was performedusing t tests and Bonferroni correction (α = 0.05). All mixtures presented genotoxic effect and only the mixture at the highest concentration (A) has presented mutagenic effect. The mixtures presented higher genotoxic and mutagenic effects than isolated pesticides at same concentrations (p < 0,05); only Cp showed significant genotoxic activity. Thus, the effects of Mt and Cp are enhanced when they are associated, even at low doses. Results presented here suggest that mixtures of Mt and Cp have different effects in health than that shown by then whenisolated. Therefore, the relationship pesticides-health must be investigated with basis in real exposure patterns.
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Sombra, Carla Maria Lima. "Biomonitoramento genotÃxico e genÃtico como indicador de risco à saÃde por exposiÃÃo ao urÃnio de residentes dos municÃpios de Monte Alegre, Prainha e Alenquer no estado do ParÃ." Universidade Federal do CearÃ, 2009. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=2865.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoA radiaÃÃo ionizante à considerada um fator de risco para o desenvolvimento de diversos tipos de neoplasias pelos danos causados à molÃcula de DNA, sendo de extrema importÃncia, portanto, o monitoramento de populaÃÃes humanas expostas a ela. O municÃpio de Monte Alegre no estado do Parà apresenta uma das maiores Ãreas de mineraÃÃo do urÃnio do mundo, que se estende aos municÃpios vizinhos de Prainha e Alenquer. Este trabalho teve como objetivos a avaliaÃÃo do potencial genotÃxico do urÃnio presente em rochas nas residÃncias de indivÃduos dos municÃpios de Monte Alegre, Prainha e Alenquer atravÃs do ensaio do cometa alcalino em linfÃcitos perifÃricos e a determinaÃÃo das freqÃÃncias de polimorfismos nos genes de reparo do DNA XRCC1 e XRCC3 e no gene de metabolizaÃÃo GSTM1 atravÃs de seqÃenciamento direto de DNA. Na anÃlise do cometa alcalino, nÃo houve diferenÃa estatisticamente significante entre os Ãndices de Dano (IDs) das populaÃÃes de Monte Alegre (ID = 32,01  1,57), Prainha (ID = 45,80  1,12) e Alenquer (ID = 44,30  0,62) e o do controle negativo (ID = 42,00  5,75) (p > 0,05). AtravÃs do seqÃenciamento direto de DNA, observou-se a presenÃa de polimorfismos nos genes XRCC1 e XRCC3 em regiÃes de Ãntrons e de Ãxons. No gene XRCC1, as freqÃÃncias alÃlicas variantes para o polimorfismo Arg194Trp nas populaÃÃes de Monte Alegre, Prainha e Alenquer foram 12%, 13% e 7% e, para Arg399Gln, 28%, 30% e 32%, respectivamente. No gene XRCC3, as freqÃÃncias do alelo variante do polimorfismo Thr241Met encontradas nas populaÃÃes de Monte Alegre, Prainha e Alenquer foram, respectivamente, 28%, 13% e 33%. Em relaÃÃo ao gene GSTM1, as freqÃÃncias obtidas de ausÃncia do gene apresentaram os valores de 36%, 31% e 40%, respectivamente Ãs populaÃÃes de Monte Alegre, Prainha e Alenquer. No geral, todas as freqÃÃncias alÃlicas nos Ãxons dos genes XRCC1 e XRCC3 e de ausÃncia do gene GSTM1 foram estatisticamente semelhantes entre os trÃs municÃpios e se mostraram em concordÃncia com freqÃÃncias obtidas em outros estudos com populaÃÃes brasileiras. Conclui-se que, dentre as populaÃÃes estudadas, nÃo houve aumento da incidÃncia de dano ao DNA pela exposiÃÃo ao urÃnio, o que pode se explicar pela baixa radiaÃÃo nessas localidades. AlÃm disso, as freqÃÃncias alÃlicas dos polimorfismos encontrados nos genes de reparo XRCC1 e XRCC3, assim como as de ausÃncia do gene de metabolizaÃÃo GSTM1 nÃo diferiram das encontradas em populaÃÃes de outras regiÃes do Brasil. Desse modo, nas regiÃes estudadas, possivelmente nÃo existe tendÃncia ao desenvolvimento de cÃncer induzido pela exposiÃÃo ao urÃnio.
Radiation is considered a risk factor for the development of several types of cancers caused by damage into the DNA molecule and is of extreme importance, therefore, the monitoring of human populations exposed to it. The municipality of Monte Alegre in the state of Parà in Brazil has one of the largest uranium mining areas of the world, which extends to the neighboring municipalities of Prainha and Alenquer. This work assessed the genotoxic potential of exposure to uranium in rocks found in dwellings in individuals from the municipalities of Monte Alegre, Prainha and Alenquer through the alkaline comet assay in peripheral blood lymphocytes and the determination of the frequencies of polymorphisms in DNA repair genes XRCC1 and XRCC3 and in carcinogen-metabolism gene GSTM1 through direct DNA sequencing. The analysis of the alkaline comet assay indicated that there was no statistically significant difference between the Damage Indexes (DIs) of Monte Alegre (DI = 32.01  1.57), Prainha (DI = 45.80  1.12) and Alenquer (DI = 44.30  0.62) and of the negative control (DI = 42.00  5.75) (p > 0.05). Through direct DNA sequencing, there were polymorphisms in XRCC1 and XRCC3 genes in regions of introns and exons. In XRCC1 gene, the variant allele frequencies for Arg194Trp polymorphism in Monte Alegre, Prainha and Alenquer populations were 12%, 13% and 7%, and for Arg399Gln, 28%, 30% and 32% respectively. In XRCC3 gene, the frequencies of the variant allele of Thr241Met polymorphism found in Monte Alegre, Prainha and Alenquer populations were, respectively, 28%, 13% and 33%. For GSTM1 gene, the frequencies obtained for the absence of this gene were 36%, 31% and 40%, respectively to Monte Alegre, Prainha and Alenquer populations. In general, the absence frequencies of GSTM1 gene and of allelic frequencies in XRCC1 and XRCC3 exons were statistically similar among the three municipalities and were in agreement with frequencies obtained in other studies with Brazilian populations. As a conclusion, among the populations studied, there was no increased incidence of DNA damage by exposure to uranium, which can be explained by the low radiation in these locations and that the allelic frequencies of polymorphisms found in the DNA repair genes XRCC1 and XRCC3, and the absence frequencies of GSTM1 gene did not differ from those in populations from other regions of Brazil. Thus, in the studied area, possibly there is no tendency to the development of cancer induced by exposure to uranium.
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Pacola, Gian Stefani. "Teste do Cometa: aplicação ao estudo de vida útil de filés de Tilápia (Oreochromis niloticus - LINNAEUS, 1758)." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/10/10134/tde-14072013-175052/.
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O presente estudo teve por objetivo avaliar o desempenho do Teste do Cometa em confronto com métodos convencionais de avaliação de frescor e qualidade higiênica e sanitária de filés de Tilápia (Oreochromis niloticus - LINNAEUS, 1758) refrigerados, durante a vida útil comercial, correlacionando os seus resultados com aqueles obtidos nas análises físico-químicas, microbiológicas e sensorial. As análises foram realizadas nos dias zero - cinco - nove - 12 - 14 pós-processamento dos filés. Em cada dia de estudo foram processados três filés diferentes, pertencentes ao mesmo lote de produto. O protocolo foi repetido em três momentos diferentes, completando 45 amostras. Nos resultados encontrou-se no dia zero e no quinto dia útil do produto, condições impróprias para consumo com relação aos microrganismos psicrotróficos e mesófilos, respectivamente, e o tipo de cometa predominante foi o tipo 3. Aos nove dias de vida útil dos filés, a média dos parâmetros Trimetilamina, Odor e Intenção de Compra indicavam produto impróprio e no teste do cometa predomina o tipo 5. Aos 12 dias de vida útil dos filés de Tilápia, refrigerados, bases voláteis nitrogenadas totais e textura obtiveram resultados impróprios, enquanto que a aparência se revelou imprópria a partir do 14º dia. Concluiu-se que o teste do cometa se presta para o estudo de vida útil de filés de Tilápia refrigerados e apresentou correlação com os métodos convencionais de avaliação de frescor e qualidade higiênica e sanitária do pescado. A partir do 9º dia de estudo predominavam cometas do tipo 5, indicativos do grau máximo de dano celular e fragmentação de DNA das células, pelo teste do cometa, o que coincidiu com a rejeição da Intenção de Compra na análise sensorial.The present study aimed to evaluate the performance of the Comet assay in comparison with conventional methods of assessing freshness and hygienic and sanitary quality of chilled Tilapia (Oreochromis niloticus - Linnaeus, 1758) fillets, over the shelf-life, correlating their results with those obtained in the physical-chemical, microbiological and sensory. The analyzes were performed on days zero - 5 - 9 - 12 - 14 post-processing of the fillets. In each study day were processed three different fillets, belonging to the same batch of product. The protocol was repeated at three different times, completing 45 samples. The results showed that at the zero and fifth day of the product, improper conditions for consumption, with respect to psychrotrophic and mesophilic microorganisms, respectively, and the predominant type of comet was the type 3. At nine days of the fillets shelf-life, the average of the parameters trimethylamine, odor and purchase intent indicate improper product, and at the comet assay predominate type 5. At 12 days of the shelf-life of chilled tilapia fillets, total volatile basic nitrogen and texture results obtained improper conditions, while appearance showed improper at the 14th day. It was concluded that the comet assay lends itself to the study of shelf-life of chilled tilapia fillets and correlated with conventional methods of assessing freshness and hygienic and sanitary qualities of fishery. From the 9th day of study, predominated comets type 5, indicative of maximum degree of cell damage and DNA fragmentation of the cells by the comet assay, which coincided with the rejection of Purchase Intent at sensory analysis.
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Almeida, Mara Ribeiro de. "Avaliação da citotoxicidade, genotoxicidade, antigenotoxicidade e expressão dos genes Tp53 e Ephx2 em ratos tratados com Caryocar villosum." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/60/60134/tde-21062013-101342/.
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O consumo de frutas e verduras está relacionado com a promoção da saúde porque tem sido associado com a redução do risco de desenvolvimento de doenças crônicas como, por exemplo, câncer e doenças degenerativas e cardiovasculares. Dessa forma, o estudo dos efeitos biológicos desses alimentos tem ganhado atenção nos últimos anos. O piquiá (Caryocar villosum) é um fruto nativo da Amazônia e é rico em compostos antioxidantes como os compostos fenólicos. Assim, o objetivo deste estudo foi avaliar os efeitos genotóxicos e antigenotóxicos in vivo da polpa liofilizada do piquiá e também de seu extrato etanólico. Além disso, os compostos fitoquímicos presentes na polpa e no seu extrato foram quimicamente determinados. Ratos Wistar foram tratados por gavagem, durante 14 dias consecutivos, com três diferentes doses da polpa do piquiá (75, 150 ou 300 mg/kg p.c.) ou com seu extrato etanólico (75 mg/kg p.c.). No 14° dia, os animais receberam solução salina (NaCl 0,9%, i.p.) ou doxorrubicina (DXR, 15 mg/kg p.c., i.p.) e após 24 horas foram eutanasiados. A medula óssea e o sangue periférico foram usados no teste do micronúcleo (MN), e o fígado, rins e coração foram utilizados nos ensaios do cometa, nas análises bioquímicas das substâncias reativas ao ácido tiobarbitúrico (TBARS) e glutationa reduzida (GSH) e na avaliação da expressão de mRNA dos genes epóxido hidrolase (Ephx2) e proteína tumoral p53 (Tp53). A polpa do piquiá não apresentou efeito genotóxico nem mutagênico em nenhuma das doses avaliadas, demonstrou atividade antigenotóxica e ainda reduziu os níveis de TBARS induzidos pela DXR no coração. Efeitos opostos foram encontrados para o extrato etanólico da polpa do piquiá, por apresentar genotoxicidade, mas não mutagenicidade, e indução de TBARS no coração. Os níveis de mRNA do gene Ephx2 no rim e coração foram aumentados após o tratamento com a maior dose da polpa do piquiá, entretanto, no rim a menor dose diminuiu a transcrição desse gene induzida pela DXR. No fígado as doses de 75 e 300 mg/kg p.c. diminuíram os níveis de mRNA do gene Ephx2 induzidos pela DXR. A dose de 300 mg/kg p.c. da polpa diminuiu a expressão de mRNA do gene Tp53 nos grupos da associação piquiá + DXR no fígado, rim e coração. O extrato etanólico da polpa do piquiá modulou a expressão de mRNA do gene Ephx2 apenas no fígado, aumentando os níveis desse transcrito, enquanto que no coração houve diminuição da transcrição do gene Tp53. Foi encontrada uma diferença de composição fitoquímica entre a polpa liofilizada e seu extrato etanólico. O extrato apresentou 1,4x mais compostos fenólicos e 3x menos carotenoides quando comparado com a polpa. Além disso, o ácido gálico foi o composto fenólico predominante na polpa, enquanto que no extrato o fenol mais abundante foi o ácido elágico. A diferença dos efeitos biológicos entre a polpa liofilizada do piquiá e seu extrato etanólico pode ser devido à alteração da composição fitoquímica.Fruit and vegetables intake has been related to the promotion of health because it has been associated to reduced risk of chronic diseases development such as cancer, and cardiovascular and degenerative diseases. Thus, the study of the biological effects of these foods has increased in recent years. Piquiá (Caryocar villosum) is a fruit native of the Amazon and it is rich in antioxidant compounds such as phenolic compounds. Therefore, the aim of this study was to evaluate the in vivo genotoxicity and antigenotoxicity effects of the piquiá lyophilized pulp fruit and its ethanolic extract. Moreover, the phytochemical characterization of pulp and extract was determined. Wistar rats were treated by gavage, for 14 days, with three doses of piquiá pulp (75, 150 or 300 mg/kg b.w.) or with its ethanolic extract (75 mg/kg b.w.). On 14th day, the animals received saline (0.9% i.p.) or doxorubicin (DXR, 15 mg/kg b.w.) and after 24 hours they were euthanized. Bone marrow and peripheral blood were used in micronucleus (MN) test, and the liver, kidney and heart were used in comet assay, thiobarbituric acid reactive substances (TBARS), reduced gluthatione (GSH), and in the evaluation of mRNA expression of epoxide hydrolase (Ephx2) and tumor protein p53 (Tp53) genes. The piquiá pulp was not genotoxic nor mutagenic, demonstrated antigenotoxic effects and reduced the TBARS levels induced by DXR in heart. The ethanolic extract had opposite effects, whereas it was genotoxic, but not mutagenic, and increased the TBARS levels in heart. Ephx2 mRNA levels in kidney and heart were increased after treatment with the higher dose of piquiá pulp, however, in kidney the lowest dose decreased the transcription of this gene induced by DXR. In liver, the 75 and 300 mg/kg b.w. doses of piquiá pulp decreased the Ephx2 mRNA levels induced by DXR. The piquiá pulp 300 mg/kg + DXR group, presented lower levels of Tp53 mRNA in liver, kidney and heart. The ethanolic extract of piquiá pulp modulated the mRNA Ephx2 expression only in the liver, increasing the levels of this transcript, while in the heart decreased the transcription of Tp53 gene. There was a difference on phytochemical composition between the pulp and its ethanolic extract. The extract presented 1.4-fold more phenolic compounds and 3-fold less carotenoids than piquiá pulp. Furthermore, gallic acid was the predominant phenol in the pulp, whereas in the ethanolic extract the most abundant phenol was the ellagic acid. The difference in the biological effects between piquiá pulp and is ethanolic extract may be due the change of the phytochemical composition.
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Russo, Angela. "The healthy effects of L. barbarum on in vitro cell models." Doctoral thesis, Università di Catania, 2018. http://hdl.handle.net/10761/4185.
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Cancer is a group of diseases characterized by the over proliferation of the cells. Epidemiological studies indicate that about 30-40% types of cancers are directly or indirectly linked to improper diet and related factors. Morover, several reports demonstrate an association between intake of fruits and vegetables and reduced mortality from degenerative diseases, including cancer.
Plants possess a variety of bioactive substances like phenols, flavonoids, carotenes and organo sulphur compounds having anti proliferative activities.
Goji is a native Chinese deciduous shrub with bright red berries. Goji has been utilized in traditional chinese medicine since the first century AD to promote longevity, to sustain the liver and improve the eyesight.
To date, several studies indicate beneficial effects of Goji berries for diabetes, high blood pressure, poor circulation, fever, malaria, inlammatory diseases, eye disorders and cancer.
Goji polysaccharide was shown to inhibit the growth of human leukemia HL-60 and human breast cancer MCF-7 cell lines. In vivo, it could enhance the anti-cancer effect of a chemotherapy on patients with various neoplasias, such as malignant melanoma, renal cell carcinoma, colorectal carcinoma, and lung cancer.
Besides the great variety of association studies, there is a need of studies to unravel its therapeutic effects at the biochemical level.
In our study, we demonstrate that Goji dry extracts do not induce in vitro tumor cell death and do not determine reduction of proliferation, using several tumor cell lines and fibroblasts and lymphocytes as normal cell controls.
Goji dry extract has shown in vitro excellent anti-inflammatory properties in a bidimensional monolayer of differentiated Caco-2 cells, as a model of the intestinal barrier. TNF-alpha-induced increase in intestinal epithelial tight junction (TJ) permeability, proposed as one of the proinflammatory mechanisms contributing to the intestinal inflammation, has been drastically reduced by Goji treatment; moreover, after 24 h incubation with the cytokine, MTT showed a beneficial protective effect when epithelial cells were treated with the Goji extract.
In our study, we have also evaluated the cellular effects by the fecal water (aqueous phase of human feces, FW), a useful biomarker approach to study cancer risks and protective activities of food.
Faecal waters from 5 healthy volunteers consuming their habitual diet were screened for genotoxicity by the single-cell gel electrophoresis (comet) assay and citotoxicity by the MTT assay, using a human cell line models, as target; goji berries supplementation increased the vitality of FW-treated cells and reduced genotoxic damages, confirming the antioxidative properities of goji.
The results showed remarkable biological activity of goji berries and dry extract and qualify it as a potential resource for food/pharmaceutical applications.
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Wu, Jian Hong. "Optimization and utilization of the comet assay for differentiation of various types of DNA damage." Thesis, University of Liverpool, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.485850.
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Mutagenic chemicals exert their effects through various mechanisms resulting in different types of DNA damage. For example, 7,l2-dimethylbenz[a]anthracene (DMBA), a potent skin carcinogen, is metabolically activated to reactive intermediates that bind to DNA to form both stable adducts and apurinic (AP) sites. Whether stable DNA adducts or AP sites are more responsible for tUmour initiation by DMBA is controversial. 8-methoxy-psoralen (8-MOP) plus UVA (pUVA), commonly used for the treatment of hyper-proliferative skin disorders, has been found to be associated with an increased risk of squamous cell cancer. Interstrand crosslink (ICL) formation by PUVA treatment is considered the major factor contributing to the carcinogenesis. However, it is recently suggested that PUVAinduced oxidative damage may playa role. Therefore, it is of importance to detect and subsequently characterize different types ofDNA lesions induced by mutagenic chem.icals to. obtain a better understanding of their potential contributions to carcmogeneSIS. This project aimed to: i) establish a technique which permits rapid and accurate measurement of various types of DNA lesions, such as AP sites, stable bulky adducts, ICLs, and oxidative DNA damage; ii) apply this technique to investigate the proportion of stable adducts and AP sites generated by DMBA in human keratinocyte cell line (HaCaT) and in human primary keratinocytes; iii) utilize the technique to study PUVA-induced ICLs and oxidative DNA damage in HaCaT cells and in reconstructed human epidermis; and iv) employ the method to assess PUVAinduced ICL formation and repair in Fanconi anaemia (FA)-like Chinese hamster cell mutants. The results indicated that AP sites were induced in both HaCaT cells and in primary human keratinocytes treated with DMBA, at a dose range of 1O~M to 1OO~M, in a dose-response manner, with HaCaT cells showing approximately 2-fold higher AP site formation than the primary human keratinocytes. Attempts to utilise the alkaline comet assay to measure stable adducts with the lesion-specific enzyme UvrABC were not successful. PUVA-induced ICLs were measured using the alkaline comet assay with a post-lysis y-irradiation. A clear dose-dependent response ofHaCaT cells to PUVA exposure is observed with a combination of a fixed UVA dose at O.05J/cm2 and a dose of 8MOP ranging from lO~M to lOO~M. Results also indicated that the ICL repair was concentration-dependent. All attempts to establish the comet assay in the reconstructed human epidermis failed due to the inability to obtain single cell suspensions from the tissues. It was also found that the comet assay is insensitive in detecting oxidative damage without lesion specific enzymes. The analysis of induction and repair of PUVA-induced ICLs in the putative FaneL defective Chinese hamster mutant DEB1 demonstrated that it exhibits slow repair of these lesions compared to its wild-type parent V79. Repair was also examined in DEB1 cells transfected with the wild-type and mutant (point mutation in ubiquitin ligase motif) versions of human FANCL cDNA. The former showed restoration of the rate ofICL repair, whilst the mutant cDNA only conferred partial correction.
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Kurzawa-Zegota, Malgorzata. "In vitro chemically-induced DNA damage in cancer patients and healthy individuals : the effect of genotoxic compounds in cells from polyposis coli, colon cancer patients and healthy individuals." Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5186.
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In the present study DNA damage was measured in peripheral blood lymphocytes from polyposis coli and colorectal cancer patients, treated with different dietary and environmental compounds and compared with lymphocytes from healthy individuals. In addition, confounding factors such as age, gender, alcohol intake and smoking habits were taken into consideration. The assays used in this study included the Comet assay, the Micronucleus assay, the Micronucleus-FISH assay and the sister chromatid exchange assay. The food mutagens, PhIP and IQ, as well as titanium dioxide nanoparticles (TiO2 NPs) induced a dose dependent increase in the DNA damage and chromosomal abnormalities in all tested groups regardless of confounding factors. Prior to experiments physicochemical characterisation of nanoparticles was conducted. In the presence of the flavonoids, quercetin and rutin that were acting in an antioxidant manner, the DNA damage resulting from the highest doses of food mutagens was significantly reduced. Thus, dietary supplementation with flavonoid-rich vegetables and fruits may prove very effective in protection against oxidative stress. The polyposis coli and colon cancer patients were more susceptible to food mutagens, PhIP and IQ, as well as TiO2 NPs, and in the majority of cases had a higher level of DNA damage in the Comet assay and higher cytogenetic damage in the Micronucleus assay. In the final project, twelve frequently encountered (NewGeneris) chemical compounds were evaluated to establish their damaging potential in lymphocytes and spermatozoa from healthy donors. The highest damage was produced by DNA reactive aldehydes, food mutagens and benzo[a]pyrene when assessed with the neutral and alkaline Comet assay with and without metabolic activation.
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Assunção, Dornelles. "Avaliação do dano genético em células sanguíneas de quirópteros de áreas urbanas e não urbanas." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/5959.
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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
The evaluation of DNA damage was carried out with the comet assay from blood samples of three bat species sampled at municipal parks of Goiania and Cerrado remnants, located in rural areas of the municipalities of Bela Vista and Urutaí, Goias state. The species sampled in the urban area were Artibeus lituratus, Artibeus planirostris and Platyrrhinus lineatus. In non-urban areas, only Artibeus planirostris was sampled. These frugivorous species are abundant and well adapted to different environments, including urban and agricultural areas. The remaining vegetation of the urban environment was very impacted and it was included in the most urbanized area of the city, with heavy traffic of vehicles, large concentration of buildings and high population density. Sampling in non-urban environments were held in Cerrado fragments in a rural area surrounded by pasture and agricultural activities. Thus, the DNA damage found in the urban environment bats were compared to verify whether there was significant variation among the parks, between species and if weight influenced the variation of the DNA damage. The DNA damage obtained for A. planirostris allowed to compare the urban and non-urban environment to identify in which of the environments this species presented higher DNA damages. The results showed that in the nonurban environment, the DNA damage was higher than in the urban environment being statistically significant. Moreover, in the urban environment, the increased DNA damage was associated with a reduction in area of the parks. In general, in the urban environment, the DNA damage may be linked indirectly to the edge effect and other environmental stressors, while in non-urban environment, higher levels of DNA damage may be related to pesticides used in the agricultural activities.
A avaliação do dano ao DNA em morcegos foi realizada com o ensaio cometa, a partir de amostras sanguíneas coletadas de 3 espécies capturadas em parques municipais de Goiânia e remanescentes de Cerrado situados na zona rural dos municípios de Bela Vista e Urutaí, ambos no Estado de Goiás. As espécies amostradas na área urbana de Goiânia foram Artibeus lituratus, Artibeus planirostris e Platyrrhinus lineatus. Nas áreas não urbanas, apenas Artibeus planirostris foi amostrado. Estas espécies frugívoras são abundantes e bem adaptadas a diversos ambientes, incluindo o meio urbano e regiões destinadas a agricultura. Os fragmentos vegetais remanescentes amostrados no ambiente urbano estão bastante impactados e inseridos na região mais urbanizada da cidade, com tráfego intenso de veículos, grande concentração de edifícios e densidade populacional elevada. As amostragens em ambiente não urbano foram realizadas em fragmentos de Cerrado na área rural, cercados por pastagem e atividades agrícolas. Dessa forma, foi comparado o dano encontrado no DNA dos morcegos para verificar se no ambiente urbano o dano varia significativamente entre os locais, entre as espécies e se o peso teria influência nessa variação. O dano ao DNA da espécie A. planirostris foi comparado entre os ambientes urbano e não urbano, para identificar em qual dos ambientes havia maiores índices de dano. Os resultados demonstraram que no ambiente não urbano, o dano ao DNA foi mais elevado que no ambiente urbano, sendo estatisticamente significativo. Além disso, no ambiente urbano, o aumento no dano ao DNA está relacionado à redução na área dos parques. Dessa forma, no ambiente urbano, o dano ao DNA parece estar associado ao efeito de borda e outros fatores estressores típicos desse ambiente, enquanto no ambiente não urbano, os valores mais elevados de dano ao DNA podem estar relacionados aos agrotóxicos e pesticidas utilizados nas atividades agrícolas.
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Costa, Cássia Cinara da. "Avaliação do dano e do reparo de DNA antes e depois do teste da caminhada dos seis minutos em pacientes portadores de doenças pulmonar obstrutiva crônica (DPOC)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/14714.
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A doença pulmonar obstrutiva crônica (DPOC) é uma doença inflamatória com participação de macrófagos, neutrófilos e linfócitos CD8, associada a estímulos oxidantes diretamente nas estruturas pulmonares, causada mais comumente pelo tabagismo. Recentemente foi demonstrado que o teste de caminhada dos seis minutos (TC6) é capaz de aumentar a inflamação e gerar o aumento de espécies reativas de oxigênio. O presente estudo teve como objetivo avaliar os níveis de dano e reparo de DNA em portadores de DPOC, quando submetidos ao TC6. Para avaliar o dano de DNA, amostras de sangue periférico foram coletadas antes e imediatamente após o TC6. Para avaliar a capacidade de reparo, foi analisada uma amostra coletada 48 horas após o TC6. Todas as amostras foram processadas pela técnica do cometa. Vinte e sete pacientes portadores de DPOC foram avaliados, sendo 59% homens. A média de idade foi de 64,7 ± 8,4 anos. A média do VEF1 foi de 40,3% ± 18,4% do previsto, com relação média de VEF1/CVF de 52,5% ± 11,9%. Todos fumaram em média 36,7 ± 17,0 anos, uma média de 48,1 ± 37,5 maços/ano. As médias das variáveis obtidas no início e no final do TC6 foram: SpO2 (92,0 ± 4,5 vs. 91,4 ± 4,6), percepção da dispnéia pela escala de BORG (1,2 ± 1,0 vs. 2,4 ± 1,7) e a distância percorrida foi em média de 380,1± 84,4 m. As taxas médias de dano de DNA antes do TC6 (27,9 ± 19,2) e imediatamente após (29,6±29,6) não apresentaram diferenças significativas (p=0,904). A análise realizada 48 horas após o TC6 demonstrou uma redução não significativa deste dano (18,3 ± 13,0, p=0,099). Conclui-se neste estudo que o esforço físico realizado durante o TC6 não provoca aumento imediato nas taxas de dano de DNA, nem estimula os mecanismos de reparo do DNA em portadores de DPOC.Chronic obstructive pulmonary disease is an inflammatory disease in which macrophages, neutrophils and CD8 T lymphocytes play an important role. It is associated with direct oxidant stimuli of lung structures, which are most frequently triggered by smoking. A recent study showed that the 6-minute walk test (6MWT) increases inflammation and reactive oxygen species. This study evaluated DNA damage and repair in patients with COPD that took the 6MWT. To evaluate DNA damage, peripheral blood samples were collected before and immediately after 6MWT. To evaluate repair, a sample was collected 48 hours after the 6MWT. All samples were prepared for the comet assay. Twenty-seven patients with COPD were evaluated; 59% were men and mean age was 64.7 ± 8.4. Mean FEV1 was 40.3% ± 18.4% of predicted value, and mean FEV1/FVC was 52.5% ± 11.9%. Mean values before and after 6MWT were: SpO2 = 92.0 ± 4.5 vs. 91.4 ± 4.6; Borg score for dyspnea = 1.2 ± 1.0 vs. 2.4 ± 1.7; and mean distance walked – 380.1 ± 84.4 m. Mean DNA damage values before (27.9 ± 19.2) and immediately after (29.6 ± 29.6) 6MWT were not significantly different (p = 0.904). The analysis performed 48 hours after 6MWT showed a nonsignificant reduction of damage (18.3 ± 13.0; p = 0.099). Conclusions The physical effort during 6MWT did not cause an immediate increase in DNA damage, and did not stimulate DNA repair mechanisms in patients with COPD.
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Rodrigues, Vera Regina Cavalcante Barros. "AvaliaÃÃo das AlteraÃÃes HematolÃgicas, BioquÃmicas e GenotÃxicas nos Trabalhadores Expostos à AgrotÃxicos em MunicÃpios do Estado do PiauÃ." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=6877.
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nÃo hÃA utilizaÃÃo de agrotÃxicos na agricultura elevou rapidamente seu consumo, especialmente de forma indiscriminada, sendo o Brasil um dos maiores mercados, representando 16% da venda mundial. No PiauÃ, a expansÃo agrÃcola na regiÃo dos cerrados contribuiu para o aumento do seu uso, expondo os agricultores a danos ao DNA. O objetivo desse estudo foi avaliar os efeitos tÃxicos e genotÃxicos nos agricultores piauienses expostos aos agrotÃxicos, com o uso de biomarcadores hematolÃgicos, bioquÃmicos e genotÃxicos. A populaÃÃo estudada consistiu de 60 trabalhadores expostos aos agrotÃxicos dos municÃpios de Barras e Josà de Freitas e 55 indivÃduos controle, sem histÃria de exposiÃÃo a agroquÃmicos. Para caracterizaÃÃo da populaÃÃo foi aplicado questionÃrio sÃcio epidemiolÃgico, de acordo com a International Commission for Protection Against Environmental Mutagens and Carcinogens-ICPEMC. Foram coletados 10 mL de sangue perifÃrico para realizaÃÃo das anÃlises hematolÃgicas, bioquÃmicas e ensaio cometa, que foram processadas pelo LACEN-PI. A mÃdia de idade foi de 34 anos, de etnia negra, na maioria, com tempo de trabalho, em mÃdia de 13,55 anos, carga horÃria de 41,5 horas semanais e 50% dos trabalhadores utilizavam pelo menos um tipo de EPI. Quanto aos hÃbitos de vida, 66,7% dos trabalhadores expostos informou nÃo consumir vegetais, 41,7 % eram fumantes e 73,3% consumiam bebidas alcoÃlicas. Do total do grupo exposto, 33,3% usava medicamentos prescritos e 66,7% usava medicamentos nÃo prescritos. No estudo foi evidenciado maior uso na agricultura de herbicidas (81,1%) e inseticidas (16,3%). No grupo dos trabalhadores expostos, 55% apresentaram leucopenia e 6,7% apresentaram diminuiÃÃo na contagem de cÃlulas vermelhas. Foram evidenciadas alteraÃÃes na creatinina plasmÃtica (p < 0,05); nas transaminases e fosfatase alcalina (p< 0,01) quando comparado o grupo exposto com o nÃo exposto. Nos resultados do ensaio cometa, o grupo exposto apresentou, em relaÃÃo ao grupo nÃo exposto, uma mÃdia de (32,13 vs 10,12) de Ãndice de dano, e frequÃncia do dano (21,82 vs 9,38), respectivamente. Na classe 1, a genotoxicidade observada foi de 17% para os expostos e 9% para os nÃo expostos. NÃo houve significÃncia entre os danos no DNA em relaÃÃo Ãs variÃveis: tempo de trabalho, nÃo uso de EPI, hÃbito de fumar, consumo de Ãlcool e nÃo consumo de vegetais. Conclui-se que os trabalhadores expostos a agrotÃxicos apresentaram alteraÃÃes enzimÃticas, hematolÃgicas (leucopenia) e instabilidade genÃtica, avaliados por parÃmetros bioquÃmicos e genotÃxicos, demonstrando assim a importÃncia do biomonitoramento dos trabalhadores como uma estratÃgia de vigilÃncia em saÃde do trabalhador no Estado do PiauÃ.
The use of pesticides in agriculture rapidly increased their consumption, especially indiscriminate consumption, being Brazil currently the largest market for pesticide in the world, representing 16% of worldwide sales. In the state of PiauÃ, the agricultural expansion in the region of Cerrado contributed to their increased use, exposing farm workers to damages to the DNA. The purpose of this study was to evaluate the toxic and genotoxic effects in farm workers exposed to pesticides in PiauÃ, with the use of hematologic, biochemical and genotoxic biomarkers. The population in analysis consisted of 60 farm workers from the municipalities of Barras and Josà de Freitas occupationally exposed to pesticides and 55 control individuals with no history of exposure to agrochemicals. To obtain the characteristics of the population, a social-epidemiological questionnaire was applied, recommended by International Commission for Protection Against Environmental Mutagens and Carcinogens-ICPEMC. 10 mL of peripheral blood were collected for haematological, biochemical and comet assay analyses, all of which were processed by LACEN-PI. The mean age was 34 years, of black ethnicity, mostly with an average of 13.55 years of work, workload of 41.5 weekly hours and 50% of workers used at least one type of PPE. In what concerns lifestyle, 66.7% of the exposed workers said they did not consume vegetables, 41.7% were smokers and 73.3% consumed alcohol. Of the total of the exposed group, 33.3% used prescribed medication and 66.7% used non-prescribed medication. In the study, it was evidenced a higher use of herbicides (81.1%) and insecticides (16.3%) in agriculture. In the group of exposed workers, 55% had leucopenia and 6.7% showed a decrease in the red blood cell count. It was found variation in plasmatic creatinine (p < 0.05); in liver enzymes and alkaline phosphatise (p < 0.01) when comparing the exposed and the non-exposed groups. In the results of the comet assay, the exposed group showed, in comparison with the non-exposed group, a mean of (32.13 vs. 10.12) of damage index and damage frequency of (21.82 vs. 9.38), respectively. In class 1, the genotoxicity observed was 17% for the exposed and 9% for the non-exposed. There was no significance between DNA damage and the following variables: workload, non-use of PPE, smoking, consumption of alcohol and non-consumption of vegetables. We concluded that workers exposed to pesticides presented toxic variations and genetic instability, which was evidenced by enzymatic variation and damages to the DNA, which thus demonstrates the importance of biomonitoring of workers as a strategy of occupational health surveillance in the state of PiauÃ.
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Spalding, Duncan Richard Castell. "An investigation of chemoresistance of liver cancers using the comet assay and isolated organ perfusion systems." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/1445199/.
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Current approaches to selecting new chemotherapies are inadequate. In vitro tissue culture models ignore the tumour microenviroment whilst murine models do not mimic human cancers. The aim of this thesis was to develop an isolated, perfused and oxygenated human liver tumour model to investigate the short term effects of chemotherapeutic agents used in the treatment of liver cancer. Expression of drug resistance transporter proteins was evaluated in hepatocellular carcinoma (HCC) and colorectal carcinoma (CRC) cell lines and did not correlate with drug resistance. P-glycoprotein (P-gp), when present, failed to demonstrate significant function. The comet assay demonstrated tumour DNA damage with chemotherapy and DNA-adduct repair with cisplatin. An orthotopic model of human liver cancer in nude mice evaluated the topographic distribution of cisplatin DNA-adducts by the comet assay in vivo. This was correlated with the presence of tumour proliferation, hypoxia, vascularity and P-gp expression determined by immunohistochemistry. Rates of repair of DNA-adducts were both quantitatively and qualitatively different from in vitro data, and superficial tumour cells were more efficient at repair in comparison with deep cells. An isolated, dual perfused liver cancer model was then developed in both the rat and human. In both models livers remained viable whilst on the perfusion circuit. Differences were observed in the timing of maximal DNA damage between drugs, and DNA damage was dose dependent. Chemotherapy induced greater tumour DNA damage in superficial as compared to deep portions of the cancers. This thesis has investigated the chemoresistance of liver cancers and developed a unique methodology for investigating human liver cancers using an ex vivo perfusion model. New insight into early DNA damage with chemotherapy has been demonstrated but more importantly the scientific basis established for a new approach to refining conventional therapies or evaluating new biological cancer therapies.
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Kizilian, Narine. "Prediction of radiosensitivity by measurement of radiation-induced apoptosis in human blood using the comet assay." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0017/MQ48501.pdf.
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Kizilian, Narine Carleton University Dissertation Physics. "Prediction of radiosensitivity by measurement of radiation-induced apoptosis in human blood using the comet assay." Ottawa, 1999.
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Qualhato, Gabriel. "Efeitos toxicológicos de nanopartículas de maghemita (γ-Fe2O3) em células e tecidos de Poecilia reticulata." Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/8613.
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Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG
The environmental risk of nanomaterials (NMs) designed and used in nanoremediation process is of emerging concern, but their ecotoxilogical effects to aquatic organism remains unclear. In this present study, the citrate-coated (maghemite) nanoparticles (IONPs) were synthesized and its genotoxic, mutagenic, the melanomacrophage centers (MMC) response and hepatic histopathological biomarkers were investigated in female guppy. Fish were exposed to IONPs at environmentally relevant iron concentration (0.3 mg L-1) during 21 days and the animals were collected at the beginning of the experiment and after 3, 7, 14 and 21 days of exposure. The genotoxicity and mutagenicity were evaluated in terms of DNA damage (comet assay), micronucleus (MN) test, erythrocyte nuclear abnormalities (ENA) frequency and the liver were dissected and fixed dehydrated through increasing ethanol gradient, immersed in xylene PA, embedded in paraffin, performed of liver sections (5 μm thick) (3 sections per animal) in the microtome, stained by Mallory’s Trichrome and H. E. and analyzed. Results showed differential genotoxic and mutagenic effects of IONPs in the P. reticulata according to exposure time. The IONP induced DNA damage in P. reticulata after acute (3 and 7 days) and long-term exposure (14 and 21 days), while the mutagenic effects were observed only after long-term exposure. The DNA damage and the total ENA frequency increase linearly over the exposure time, indicating a higher induction rate of clastogenic and aneugenic effects in P. reticulata erythrocytes after long-term exposure to IONPs. Guppies exposed to IONPs showed increasing in the number, area and perimeter of MMC when compared to the unexposed ones, especially after 7 days of exposure. The results showed an increase in the frequency of histopathological changes in fish after the 7 days of exposure to IONPs, such micro- and macro-vesicular steatosis, melanomacrophage aggregates, exudate and haemorrhagic foci. The acute (3 and 7 days) and long-term (14 and 21 days) exposure of P. reticulata to IONPs induced high histopathological indexes associated with circulatory disorders and inflammatory responses. Results indicated that blood system and liver tissue of P. reticulata are excellent target organs to studies the ecotoxicity of IONPs. Confirming that P. reticulata is a biomonitor specie indicated for studies of ecotoxicity of IONPs.
O risco ambiental dos nanomateriais projetados e utilizados para nanoremediação se mostram hoje de grande interesse econômico e ambiental, mas seus efeitos ecotóxicológicos para os organismos aquáticos ainda permanecem obscuros. Neste presente estudo, as nanopartículas de oxido de ferro funcionalizadas com citrato (maghemita) (NOFs) foram sintetizadas e seus efeitos genotóxicos, mutagênicos, e histopatológicos foram investigados em fêmeas de Poecilia reticulata. Os peixes foram expostos a maghemita em concentrações de ferro ambientalmente relevantes (0,3 mg.L-1) durante 21 dias e os animais foram coletados no início do experimento e após 3, 7, 14 e 21 dias de exposição. A genotoxicidade e a mutagenicidade foram avaliadas por meio do dano causado ao DNA (Ensaio cometa), o teste do micronúcleo (MN) e anormalidades nucleares de eritrócitos (ANE) avaliaram o potencial mutagênico. Os fígados foram dissecados, fixados, desidratados em etanol, imersos em xilol, embebidos em parafina, e seccionados com 5 μm de espessura, os cortes corados em H.E. e Tricrômico de Mallory foram analisados e obtidos dados histomorfométricos. Os resultados mostraram efeitos genotóxicos e mutagênicos diferenciais das NOFs em P. reticulata de acordo com o tempo de exposição. As NOFs induziram danos ao DNA após exposição aguda (3 e 7 dias) e de longo prazo (14 e 21 dias), enquanto os efeitos mutagênicos foram observados somente para a exposição prolongada. O dano no DNA e a frequência total de ANE aumentaram linearmente ao longo do tempo de exposição, indicando uma maior taxa de indução de efeitos clastogênicos e aneugênicos em eritrócitos de P. reticulata após exposição prolongada a NOFs. Os guppies expostos também mostraram aumento do número, área e perímetro dos MMC quando comparados ao grupo controle, especialmente após 7 dias de exposição. Os resultados mostraram um aumento na frequência de alterações histopatológicas em peixes após os 7 dias de exposição as NOFs, tais como esteatose micro- e macro-vesicular, aumento dos MMC, exsudatos e focos hemorrágicos. A exposição aguda (3 e 7 dias) e a longo prazo (14 e 21 dias) de P. reticulata a NOFs induziu índices histopatológicos elevados associados a distúrbios circulatórios e respostas inflamatórias. Os resultados indicaram que os tecidos sanguíneo e hepático dos guppies são excelentes órgão alvo para estudar a ecotoxicidade das NOFs, confirmando que o P. reticulata é uma espécie biomonitora indicada para estudos sobre a ecotoxicidade das NOFs.
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Terrazas, Peterson Menezes. "Investigação dos efeitos citotóxico e genotóxico do extrato de salix alba L. análises in vitro, in vivo e histológicas /." Botucatu, 2017. http://hdl.handle.net/11449/152402.
Full textAbstract:
Orientador: Edson Luis MaistroResumo: A Salix alba L. (SA), popularmente conhecida como Salgueiro Branco, é uma planta utilizada na medicina popular para o tratamento de inflamações crônicas e agudas, infecções, dores, febre, entre outros. A caracterização fitoquímica do extrato da casca desta planta revelou que seu principal componente é a salicina, com uma concentração de 4,94 mg/mL, um precursor do anti-inflamatório ácido acetilsalicílico. Considerando que existem poucos estudos que avaliam a ação tóxica e citotóxica do extrato da SA, o presente estudo foi elaborado visando investigar o potencial citotóxico, genotóxico e mutagênico da SA em células mononucleares do sangue periférico humano e de hepatocarcinoma humano HepG2 in vitro, e em diferentes células de camundongos in vivo, utilizando alguns dos testes tradicionais na área de mutagênese, como o teste do MTT, o Ensaio do Cometa e o Teste do Micronúcleo, bem como a verificação de potencial citotoxicidade por meio de análises histológicas e histoquímicas. Os testes de viabilidade celular e citotoxicidade (azul de tripan e MTT) permitiram a escolha de 3 concentrações do extrato da SA para serem analisadas nos ensaios de genotoxicidade in vitro: 5, 50 e 100 µg/mL. Pelo ensaio cometa com as células mononucleares de sangue periférico, pôde-se observar que as concentrações de 50 e 100 µg/mL acarretaram um aumento estatisticamente significativo de danos no DNA, em comparação ao controle negativo. Já no teste do micronúcleo, as 3 concentrações avaliadas (5, 50 e 1... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Salix alba L. (SA), popularly known as White Willow, is a plant used in folk medicine for the treatment of chronic and acute inflammations, infections, pains, fever, among others. The phytochemical characterization of the bark extract of this plant revealed that its main component is salicin, with a concentration of 4.94 mg/mL, a precursor of the antiinflammatory acetylsalicylic acid. Considering that there are few studies evaluating the toxic and cytotoxic action of SA extract, the present study was designed to investigate the cytotoxic, genotoxic and mutagenic potential of SA bark wood extract in human peripheral blood mononuclear cells and human hepatoma cell line HepG2 in vitro and in different mouse cells in vivo using some of the traditional mutagenesis tests such as the MTT test, the Comet assay and the Micronucleus test, and cytotoxicity in the liver of mice also by histological and histochemical analysis. Cell viability and cytotoxicity tests (trypan blue and MTT) allowed the choice of 3 concentrations of the SA extract to be analyzed in the in vitro genotoxicity assays: 5, 50 and 100 μg/mL. By the comet assay with the peripheral blood mononuclear cells, it was observed that concentrations of 50 and 100 μg/ml resulted in a statistically significant increase in DNA damage, as compared to the negative control. In the micronucleus test, the 3 concentrations evaluated (5, 50 and 100 μg/mL) did not produce significant increases of micronucleated binucleate cells, as well ... (Complete abstract click electronic access below)
Doutor
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Coronas, Mariana Vieira. "Biomonitoramento de populações humanas em áreas de exposição a poluentes atmosféricos mutagênicos." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/13649.
Full textAbstract:
Processos industriais utilizam e geram uma variedade de compostos que são liberados e dispersados no ambiente. Sobre a maioria dessas substâncias, muitas sendo recentemente sintetizadas, não se tem o devido conhecimento e controle, o que pode causar diversos prejuízos ao ambiente e à saúde humana, sendo as populações do entorno das fontes emissoras as primeiras a se exporem. Nesse contexto, uma avaliação que estime o potencial efeito de uma mistura de substâncias à determinada população requer um trabalho extenso e multidisciplinar. O presente estudo teve como objetivo avaliar, através de marcadores genéticos, a presença de atividade mutagênica no material particulado atmosférico como marcador de exposição e diagnóstico ambiental em áreas sob influência industrial petroquímica, associando o biomonitoramento humano em população urbana exposta à atividade industrial. Foram avaliadas amostras de material particulado atmosférico, através do ensaio Salmonella/microssoma, de áreas que recebem as emissões atmosféricas do complexo petroquímico do sul, Triunfo (RS), e de uma refinaria de petróleo em Esteio (RS) e, para comparação, uma área urbana em Porto Alegre (RS) também foi avaliada. Todos os locais estudados apresentaram respostas positivas para mutagenicidade e indicaram a presença de mutágenos diretos e indiretos, e de nitrocompostos, como nitroarenos, aminas aoromáticas e nitro-PAHs. Amostras de sangue e mucosa oral de homens residentes e/ou trabalhadores na área influenciada pela refinaria de petróleo foram avaliadas quanto ao dano no DNA através do ensaio cometa e micronúcleo, respectivamente. Este grupo de indivíduos foi comparado a um grupo de referência similar entre os habitantes do município de Santo Antônio da Patrulha (RS), caracterizado como fora das principais áreas industriais do Estado. Não houve diferença entre a freqüência de células micronucleadas entre os grupos. No entanto, o ensaio cometa se mostrou sensível na detecção de dano ao DNA em indivíduos do grupo exposto. Nenhum dos fatores com possibilidade de interferência no parâmetro avaliado (fumo, idade e radiação) mostraram associação com aumento de dano detectado pelo ensaio cometa. Os ensaios biológicos utilizados no diagnóstico ambiental e no biomonitoramento da população foram ferramentas úteis na avaliação de áreas influenciadas por atividades humanas. Assim, o ensaio Salmonella/microssoma além de fornecer informações sobre os efeitos biológicos resultantes das misturas presentes no ambiente, também indicou as classes dos compostos e sua contribuição ao efeito observado. Já o ensaio do cometa foi indicativo importante no biomonitoramento da exposição humana à mistura de agentes genotóxicos ambientais. Esses resultados indicam que os atuais parâmetros de qualidade do ar não são suficientes para evitar efeitos adversos ao ambiente e à saúde humana.Industrial processes use and generate a variety of compounds that are liberated and dispersed in the environment. Most of those substances, many recently synthesized, still do not have the understanding and control they deserve, which can cause several damages to the environment and human health, and the populations surrounding the emission sources are the first to be exposed. In this way, any evaluation estimating the potential effect of a mixture of substances to a particular population require an extensive multi-disciplinary approach. The present study had as objective to evaluate, through genetic biomarkers, the presence of mutagenic activity in the airborne particulate matter as an exposure marker and environmental diagnosis in areas under influence of petrochemical industry, associating the human biomonitoring in urban population exposed to industrial activities. Airborne particulate matter samples were evaluated through Salmonella/microsome assay. Samples from areas receiving atmospheric emissions from a petrochemical complex (Triunfo, RS), an oil refinery (Esteio, RS) and an urban area (Porto Alegre, RS) were evaluated. All studied areas showed positive responses for mutagenicity, indicating that direct and indirect-acting mutagens were present in airborne particulate matter. Also, the mutagenic responses indicate the participation of nitrocompounds, like nitroarenes, hydroxylamines, nitro-PAHs and aromatic amines in the total mutagenicity. Samples of blood and buccal mucosa, from males residing and/or working downwind from an oil refinery, were evaluated in singlecell gel electrophoresis assay (comet assay) and micronucleus (MN) assay, respectively. This studied group was compared to males from another town (Santo Antônio da Patrulha, RS, Brazil) situated in an urban area with restricted traffic and industrial influence, constituting the reference group. No difference in micronucleated cells frequencies was observed between groups. Comet assay was sensitive to detect DNA damage in subjects from exposed group. No association was found between possible confounding factors (tobacco smoking, age and radiation exposure) and increased DNA damage. Biological tests in monitoring and environmental diagnosis studies, in areas under influence of anthropogenic activities, were useful tools to screen which chemical genotoxic compound classes are present. It also indicates that the current air quality standards are not sufficient to avoid damage to the environment and human health.
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Habas, Khaled S. A. "In vitro studies on genotoxicity and gene expression in spermatogenic cells: mechanisms and assay development." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/14386.
Full textAbstract:
Spermatogenesis is a complex process of male germ cell development from
diploid spermatogonia to haploid fertile spermatozoa. Apoptosis plays a vital
role in limiting cell numbers and eliminating defective germ cells. This requires
novel gene products, and precise and well-coordinated programmes of gene
expression. It is therefore possible that a disruption of transcription factor
function would significantly impact germ cell development.
The present work was undertaken to use Staput separation followed by culture
of purified germ cells of rodent testis since mammalian spermatogenesis cannot
yet be recreated in vitro. Specificity of separation was assessed using
immunocytochemistry to identify spermatogonia, spermatocytes and spermatids. The
genotoxins H2O2, doxorubicin, N-ethyl-N-nitrosourea, N-methyl-N-nitrosourea,
6-mercaptopurine, 5-bromodeoxyuridine, methyl methanesulphonate
and ethyl methanesulphonate were investigated.
Cells were cultured and treated with different concentrations for each agent.
DNA damage and apoptosis were measured by Comet and TUNEL assay
respectively. Up-regulation of expression of the transcription factors Tbpl1,
FHL5 and Gtf2a1l that are important post-meiotically, were examined using RT-
PCR and qPCR. Protein production was evaluated using Western blotting.
Tbpl1, FHL5 and Gtf2a1l were cloned in-frame into the inducible expression
vector pET/100-TOPO. The recombinant clones were induced and successful
expression of the proteins in E. coli was confirmed by SDS-PAGE and Western
blotting. The recombinant clones obtained were used to demonstrate genotoxin
induced impairment of gene expression.
Thus, Staput-isolated rodent testicular germ cells seem to be a suitable model
to study genotoxicity in vitro yielding result comparable to those reported in vivo.
Furthermore, the work shows that genotoxins can impair gene expression.
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JOHNSON, BRIAN REAVES. "THE ROLE OF ATAXIA TELANGIECTASIA-MUTATED AND NIJMEGEN BREAKAGE SYNDROME PROTEIN-1 IN THE ACCUMULATION OF UVC-INDUCED DNA REPLICATION-DEPENDENT DOUBLE STAND BREAKS." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1022158038.
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Livingston, Justin Ryan. "The Antioxidant and DNA Repair Capacities of Resveratrol, Piceatannol, and Pterostilbene." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/5525.
Full textAbstract:
Lifestyle diseases represent a large burden on developed societies and account for much morbidity worldwide. Research has shown that eating a diet rich in fruit and vegetables helps to ameliorate and prevent some of these diseases. Antioxidants found in fruits and vegetables may provide a substantial benefit in reducing disease incidence. This thesis examines the antioxidant properties of resveratrol, piceatannol, and pterostilbene, and the ability of Burkitt's Lymphoma (Raji) cells to uptake these three antioxidants. It also studies the effect of the antioxidants in protecting against DNA damage and their role in DNA repair following oxygen radical exposure in Raji cells. The Oxygen Radical Absorbance Capacity (ORAC) assay was used to measure overall antioxidant contribution as well as the ability of Raji cells to uptake antioxidant following exposure to 2,2’-Azobis(2-methyl-propionamide) dihydrochloride (AAPH). The single cell gel electrophoresis (Comet) assay was used to assess DNA damage and DNA repair rates of cells. Results showed that Raji cells, following oxygen radical exposure, significantly uptake pterostilbene (p < 0.0001), but not piceatannol or resveratrol. Piceatannol provided protection against hydrogen peroxide induced DNA damage, but pterostilbene and resveratrol increased DNA damage following hydrogen peroxide treatment. None of the compounds showed any effect on DNA repair. Overall, this study indicates there is merit for further research into the bioactive roles, including antioxidant capacity, of all three compounds. Such research may provide evidence for the more widespread use of these and other food based compounds for preventing lifestyle diseases.
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Attia, Atef Mahmoud Mahmoud. "Induction of DNA double-strand breaks at various stages of the cell cycle using the comet assay." [S.l.] : [s.n.], 2002. http://webdoc.sub.gwdg.de/diss/2002/attia/attia.pdf.
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Nehls, Sebastian. "Anwendung des Comet Assay (Einzelzell-Gelelektrophorese) an Zellen von Fischen zum Nachweis gentoxischer Wirkungen im aquatischen Biomonitoring." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16830.
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Gewässer sind Lebensgrundlage, jedoch gleichzeitig Schadstoffsenken für eine Vielzahl von Kontaminanten. Biologische Wirkungstests und das Biomonitoring aquatischer Proben sind daher besonders wichtig, um Umwelt-Gefahrenpotenziale erkennen zu können. Der "Comet Assay" (Einzelzell-Gelelektrophorese) ist ein Indikator von DNA-Strangbrüchen und wurde hier als Test auf gentoxische Wirkungen erprobt und angewandt. Mit bekannten, gentoxischen Substanzen wurden Nachweisgrenzen und Dosis-Wirkungs-Beziehungen für die Zelllinien RTG-2 und RTL-W1 (aus der Regenbogenforelle, Oncorhynchus mykiss) in vitro ermittelt und methodische Parameter an die Zellen angepasst. Der Test reagierte sehr sensitiv auf 4-Nitrochinolin-1-oxid. Die Substanz war daher geeignet, um in weiteren Versuchen als Positivkontrolle zu dienen. Zur Bewertung der Messdaten wurde ein geeignetes statistisches Verfahren gefunden, das auch historische Kontrollen mit einbezog. Der zeitliche Verlauf der DNA-Schädigung des Testsystems mit RTG-2-Zellen wurde ermittelt, und durch Inhibition der DNA-Reparatur mit Aphidicolin wurden Zusammenhänge zwischen der Entstehung von DNA-Strangbrüchen, der DNA-Reparaturkapazität sowie der Metabolisierungskapazität untersucht. In einer zweiten Phase wurden unbehandelte Wasserproben aus Rhein, Elbe sowie weitere Oberflächenwasserproben mit dem Comet Assay an RTG-2-Zellen getestet. Bei 15 von 49 Proben zeigten sich gentoxische Effekte. In einer dritten Phase wurden Erythrozyten von freilebenden Döbeln, Leuciscus cephalus, aus der Mosel mit dem Comet Assay untersucht. Die Fische von drei Messstellen zeigten erhöhte Werte von DNA-Schädigungen, gegenüber einer vierten, stromabwärts gelegenen Messstation. Korrelationen mit den Ergebnissen zusätzlicher Biomarker ergaben sich nur teilweise. Chemische Analysen von Wasser- oder Gewebeproben ließen keine Rückschlüsse auf verursachende Kontaminanten zu - gerade dies unterstreicht jedoch die Wichtigkeit biologischer Tests bei komplexen Proben.Bodies of Water are both vital resources and pollutant sinks for a multitude of contaminants. Therefore, biological effect tests and biomonitoring of aquatic samples are of particular importance to detect potential environmental hazards. The "comet assay" (single cell gel electrophoresis) is an indicator for DNA strand breaks and was explored and applied as a genotoxicity test in the present study. Known genotoxic substances were used to determine the detection limits and dose-response relationships for the cell lines RTG-2 and RTL-W1 (from rainbow trout, Oncorhynchus mykiss) in vitro, and to adapt methodological parameters to the cells. The test was very sensitive to 4-Nitroquinoline-1-oxide. This substance was therefore well-suited to serve as positive control in further experiments. In order to evaluate the measurement data, an appropriate statistical procedure was developed, which also took "historical" controls into account. The time course of DNA damage in the test system using RTG-2 cells was determined, and relationships between the origin of DNA strand breaks, DNA repair capacity and the metabolizing capacity of the cells was investigated by means of inhibition of DNA repair with Aphidicoline. In the second stage, native water samples from the rivers Rhine and Elbe and further surface waters were tested with the comet assay, using RTG-2 cells. 15 out of 49 samples showed genotoxic effects. In a third stage, erythrocytes of feral chub, Leuciscus cephalus, from the Moselle river were examined with the comet assay. The fish from three measuring stations showed elevated values of DNA damage compared to fish sampled from a downstream station. There were only partly correlations with the results from additional biomarkers. Chemical analyses of water and tissue samples did not permit conclusions on effect-causing substances.However, this emphasizes the importance of biological tests in dealing with complex environmental samples.
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Dandah, Osama M. M. "Genoprotective effect of aspirin and ibuprofen in human lymphocyte cells : effect of nano and bulk forms of aspirin and ibuprofen on lymphocytes from breast cancer patients compared with those from healthy females." Thesis, University of Bradford, 2017. http://hdl.handle.net/10454/15160.
Full textAbstract:
Various recent studies have suggested that regular intake of some non-steroidal anti-inflammatory drugs (NSAIDs) have a preventative effect against several types of tumours including breast cancer. The term nanotechnology refers to technology in which one-billionth of a meter is used as a scale for chemical particle size. This work aims to study the effect of both ibuprofen and aspirin on DNA damage using peripheral blood lymphocytes from breast cancer patients and comparing the results with those from healthy females as a control using the Comet and micronucleus assays. Western blot analysis (WBA) was used to investigate the effect of these drugs on XRCC3 and p53 proteins, whereas QPCR was to evaluate this effect on p53, cox1 and cox2 genes. Two hundred fifty ng/ml of ibuprofen (NP and bulk) and 500 ng/ml of aspirin (NP and bulk) were used to treat the lymphocytes. Both aspirin and ibuprofen caused a reduction in DNA damage and micronucleus formation. Aspirin, both forms, showed a reduction in DNA damage in the Comet and micronucleus assays. Ibuprofen both forms, by contrast, showed a statistically significant reduction in micronucleus frequency in the micronucleus assay, while its preventative effect with the Comet assay was weak or insignificant. NPs of both agents were more effective than bulk sizes. Using the Comet repair assay, aspirin and ibuprofen nano form catalysed DNA repair to a greater extent than their bulk forms. Also, both sizes showed better repair with NSAIDs compared to samples repaired without NSAIDs. In WBA aspirin increased the expression of XRCC3 protein in healthy cells. However, both NSAIDs decreased that expression in cells from BC patients. Furthermore, aspirin increased p53 expression in BC patients lymphocytes. With the QPCR method, results of both aspirin forms increased the expression of the p53 gene in BC patient cells statistically significantly. Both drugs reduced cox1 expression in healthy volunteers and cancer patients lymphocytes. Moreover, cox2 reduction was only in lymphocytes from BC patients. The results of this work are consistent with the view that NSAIDs, particularly aspirin and ibuprofen, could have a promising role in cancer treatment including breast cancer.
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Khayat, Carolinne Borges. "AVALIAÇÃO DA MUTAGENICIDADE E GENOTOXICIDADE EM TRABALHADORES RURAIS DE MUNICÍPIOS GOIANOS COM INTENSA ATIVIDADE AGRÍCOLA." Pontifícia Universidade Católica de Goiás, 2012. http://localhost:8080/tede/handle/tede/2344.
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Previous issue date: 2012-04-13The term pesticide is used to refer to a wide variety of chemicals used to kill weeds, insects and fungi. In Brazil, the use of pesticides in agriculture has been expanding continuously, and therefore the analysis of the effects of this type of environmental exposure begins to document an epidemiological profile of the distribution of cancer in both populations occupationally exposed to these chemicals as in the general population indirectly affected by contaminated food and water resources. The possible toxic effects of such exposures are unknown and the information related only to the toxicity of active ingredients are not sufficient to assess the risk of adverse effects of pesticides on human health and the environment. Workers exposed to pesticides when compared with the control group showed increased 8 times more micronucleus and 20 times more binucleated cells and increased DNA damage measured by comet assay. Variables such as smoking, alcohol consumption, age, sex, duration of exposure and type of pesticide did not affect the appearance of genetic damage. However, there was an increase of micronucleus in workers who did not use personal protective equipment. Pesticide exposure can cause genotoxicity and mutagenicity to individuals who deal with such agents.
O termo pesticida é usado para denominar uma ampla variedade de produtos químicos utilizados para destruir ervas daninhas, insetos e fungos. No Brasil, o uso de pesticidas na agricultura vem se ampliando de forma contínua e, consequentemente, a análise sobre os efeitos deste tipo de exposição ambiental começa a documentar um perfil epidemiológico da distribuição de câncer tanto em populações ocupacionalmente expostas a estes agentes químicos, como na população geral indiretamente afetada por contaminação alimentar e dos recursos hídricos. Os possíveis efeitos tóxicos de tais exposições ainda são desconhecidos e as informações da toxicidade relacionada apenas aos ingredientes ativos não são suficientes para avaliar o risco dos efeitos adversos dos pesticidas à saúde humana e ambiental. Os trabalhadores expostos a pesticidas, quando comparados ao grupo controle, tiveram aumento de 8 vezes mais micronúcleos e 20 vezes mais células binucleadas e maior dano ao DNA avaliado pelo ensaio cometa, em relação ao grupo controle (p<0,0001), como demonstrado pelo teste t e análises de regressão linear simples. Nesse estudo, variáveis como tabagismo, consumo de álcool, idade, sexo, tempo de exposição e tipo de pesticida não influenciaram o aparecimento de danos genéticos. Entretanto, houve aumento de micronúcleos em trabalhadores que não utilizavam equipamentos de proteção pessoal (p=0,006). Assim, a exposição a pesticidas, independente do tempo e tipo de agente utilizado, pode causar genotoxicidade e mutagenicidade aos indivíduos que os manipulam.
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Keretetse, Goitsemang Salvation. "DNA damage and repair detected by the comet assay in lymphocytes of African petrol attendants : a pilot study / G.S. Keretetse." Thesis, North-West University, 2007. http://hdl.handle.net/10394/1072.
Full textAbstract:
Petrol attendants are exposed to petrol volatile organic compounds (VOCs) which may have genotoxic and carcinogenic effects. The single cell gel electrophoresis assay (comet assay) is a method highly sensitive to DNA damage induced by environmental and occupational exposure to carcinogenic and mutagenic agents. The aim of this study was to evaluate the level of exposure of petrol attendants to petrol VOCs and also to determine their effect on DNA damage and repair in lymphocytes of African petrol attendants. The exposed group consisted of 20 subjects, randomly selected from three petrol stations. A control group of 20 unexposed subjects was also chosen and matched for age and smoking habits with the exposed group. Sorbent tubes were used to assess personal exposure of petrol attendants. The comet assay was used to investigate the basal DNA damage and repair capacity in isolated lymphocytes of petrol attendants and control subjects. Blood samples were taken from the petrol attendants at the end of their 8 hour working shift and also from the control subjects. The petrol attendants were found to be exposed to levels of petrol VOCs lower than the occupational exposure limit (OEL) for constituent chemicals. A significant relationship was found between the volume of petrol sold during the shift and the average concentrations of benzene, toluene and the total VOCs measured. However, relative humidity had a negative correlation with the average concentrations of benzene, toluene, xylene and the total VOCs. Significantly higher basal DNA damage was observed with the exposed group compared to the control group. The period of exposure influenced the level of DNA damage and the calculated repair capacity. Smoking and age had a significant influence on the level of DNA damage. DNA repair capacity was delayed in smokers of both exposed and non-exposed group.Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2008.
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Habas, Khaled Said Ali. "In vitro studies on genotoxicity and gene expression in spermatogenic cells : mechanisms and assay development." Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/14386.
Full textAbstract:
Spermatogenesis is a complex process of male germ cell development from diploid spermatogonia to haploid fertile spermatozoa. Apoptosis plays a vital role in limiting cell numbers and eliminating defective germ cells. This requires novel gene products, and precise and well-coordinated programmes of gene expression. It is therefore possible that a disruption of transcription factor function would significantly impact germ cell development. The present work was undertaken to use Staput separation followed by culture of purified germ cells of rodent testis since mammalian spermatogenesis cannot yet be recreated in vitro. Specificity of separation was assessed using immunocytochemistry to identify spermatogonia, spermatocytes and spermatids. The genotoxins H2O2, doxorubicin, N-ethyl-N-nitrosourea, N-methyl-N-nitrosourea, 6-mercaptopurine, 5-bromodeoxyuridine, methyl methanesulphonate and ethyl methanesulphonate were investigated. Cells were cultured and treated with different concentrations for each agent. DNA damage and apoptosis were measured by Comet and TUNEL assay respectively. Up-regulation of expression of the transcription factors Tbpl1, FHL5 and Gtf2a1l that are important post-meiotically, were examined using RT- PCR and qPCR. Protein production was evaluated using Western blotting. Tbpl1, FHL5 and Gtf2a1l were cloned in-frame into the inducible expression vector pET/100-TOPO. The recombinant clones were induced and successful expression of the proteins in E. coli was confirmed by SDS-PAGE and Western blotting. The recombinant clones obtained were used to demonstrate genotoxin induced impairment of gene expression. Thus, Staput-isolated rodent testicular germ cells seem to be a suitable model to study genotoxicity in vitro yielding result comparable to those reported in vivo. Furthermore, the work shows that genotoxins can impair gene expression.
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Yang, Xuan. "Use of Fish Biomarkers to Assess the Contaminant Exposure and Effects in Lake Erie Tributaries." The Ohio State University, 2004. http://rave.ohiolink.edu/etdc/view?acc_num=osu1101792482.
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Steenkamp, Anzaan. "Establishing the comet assay to determine the effects of different perturbations on DNA repair capacity / by Anzaan Steenkamp." Thesis, North-West University, 2011. http://hdl.handle.net/10394/4628.
Full textAbstract:
Single cell gel electrophoresis (SCGE), more commonly known as the Comet assay, is
an uncomplicated, affordable and versatile method for investigating DNA damage and
repair. Existing comet–assay based methods were modified and applied in this study in
order to examine the effects of different perturbations on the DNA repair capacity of
different samples.
Mitochondrial functioning has a vast effect on overall cell physiology and does not
simply involve the production of energy in the form of ATP that sustains common
biological processes, but is also associated with important cellular occurrences such as
apoptosis and ROS production. It is suggested that a change in mitochondrial function
may lead to extensive ROS production which may negatively affect macromolecules,
including proteins involved in DNA repair pathways, and impaired energy formation
which in turn may hamper the proper occurrence of energy driven processes. Complex I
and ?III knock–down systems established in 143B cells are used to investigate the effect
that perturbations of the energy metabolism may have on DNA repair capacity.
Metallothioneins (MTs) are known to play an imperative role in trace element
homeostasis and detoxification of metals and are effective ROS scavengers. The prooxidant
environment that heavy metal imbalance causes may result in mutagenesis and
transformation through DNA damage. It is suggested that an imbalance in the metal
homeostasis caused by MT knock–out may create an environment favourable for DNA
damage formation and at the same time impair DNA repair pathways. Because of the
multi–functionality and involvement of metallothioneins in such a wide variety of
biological processes, it was considered interesting and essential to extend the
investigation on the effect of the absence of metallothioneins on DNA repair. A
metallothionein I and ?II knock–out mouse model is employed to determine the effect of
MT knock–out on DNA repair capacity.
It was clear from the results obtained that transfection of cells, as used to investigate a
perturbation in the energy metabolism in 143B cells, has an impairing effect on DRC. It
was also confirmed that metallothioneins play an important and diverse role in cell
biology since the absence thereof inhibits both BER and NER.Thesis (M.Sc. (Biochemistry))--North-West University, Potchefstroom Campus, 2011.
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Weigel, Julia [Verfasser]. "Untersuchungen zur Zytotoxizität mittels WST-I-Assay und zur Gentoxizität mittels Comet-Assay von Portlandkompositzementen mit unterschiedlichen Zusatzstoffen, sowie Klinker und Kalksteinmehl in humanen Lungenzellen / Julia Weigel." Gießen : Universitätsbibliothek, 2013. http://d-nb.info/106506540X/34.
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