RESUMO
DNA repair pathways, cell cycle checkpoints, and redox protection systems are essential factors for securing genomic stability. The aim of the present study was to analyze the effect of Ilex paraguariensis (Ip) infusion and one of its polyphenolic components rutin on cellular and molecular damage induced by ionizing radiation. Ip is a beverage drank by most inhabitants of Argentina, Paraguay, Southern Brazil, and Uruguay. The yeast Saccharomyces cerevisiae (SC7Klys 2-3) was used as the eukaryotic model. Exponentially growing cells were exposed to gamma rays (γ) in the presence or absence of Ip or rutin. The concentrations used simulated those found in the habitual infusion. Surviving fractions, mutation frequency, and DNA double-strand breaks (DSB) were determined after treatments. A significant increase in surviving fractions after gamma irradiation was observed following combined exposure to γ+R, or γ+Ip. Upon these concomitant treatments, mutation and DSB frequency decreased significantly. In the mutant strain deficient in MEC1, a significant increase in γ sensitivity and a low effect of rutin on γ-induced chromosomal fragmentation was observed. Results were interpreted in the framework of a model of interaction between radiation-induced free radicals, DNA repair pathways, and checkpoint controls, where the DNA damage that induced activation of MEC1 nodal point of the network could be modulated by Ip components including rutin. Furthermore, ionizing radiation-induced redox cascades can be interrupted by rutin potential and other protectors contained in Ip.
Assuntos
Antimutagênicos/farmacologia , Ilex paraguariensis/química , Extratos Vegetais/farmacologia , Rutina/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Células Cultivadas , Cromatografia Líquida , Quebras de DNA de Cadeia Dupla , Reparo do DNA , DNA Fúngico/efeitos da radiação , Relação Dose-Resposta à Radiação , Raios gama , Espectrometria de Massas , Mutagênese , Taxa de Mutação , Proteção Radiológica/métodos , Reprodutibilidade dos TestesRESUMO
DNA repair pathways, cell cycle checkpoints, and redox protection systems are essential factors for securing genomic stability. The aim of the present study was to analyze the effect of Ilex paraguariensis (Ip) infusion and one of its polyphenolic components rutin on cellular and molecular damage induced by ionizing radiation. Ip is a beverage drank by most inhabitants of Argentina, Paraguay, Southern Brazil, and Uruguay. The yeast Saccharomyces cerevisiae (SC7Klys 2-3) was used as the eukaryotic model. Exponentially growing cells were exposed to gamma rays (γ) in the presence or absence of Ip or rutin. The concentrations used simulated those found in the habitual infusion. Surviving fractions, mutation frequency, and DNA double-strand breaks (DSB) were determined after treatments. A significant increase in surviving fractions after gamma irradiation was observed following combined exposure to γ+R, or γ+Ip. Upon these concomitant treatments, mutation and DSB frequency decreased significantly. In the mutant strain deficient in MEC1, a significant increase in γ sensitivity and a low effect of rutin on γ-induced chromosomal fragmentation was observed. Results were interpreted in the framework of a model of interaction between radiation-induced free radicals, DNA repair pathways, and checkpoint controls, where the DNA damage that induced activation of MEC1 nodal point of the network could be modulated by Ip components including rutin. Furthermore, ionizing radiation-induced redox cascades can be interrupted by rutin potential and other protectors contained in Ip.
Assuntos
Rutina/farmacologia , Saccharomyces cerevisiae/efeitos dos fármacos , Saccharomyces cerevisiae/efeitos da radiação , Extratos Vegetais/farmacologia , Antimutagênicos/farmacologia , Ilex paraguariensis/química , Proteção Radiológica/métodos , Espectrometria de Massas , DNA Fúngico/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Células Cultivadas , Reprodutibilidade dos Testes , Cromatografia Líquida , Mutagênese , Reparo do DNA , Relação Dose-Resposta à Radiação , Quebras de DNA de Cadeia Dupla , Taxa de Mutação , Raios gamaRESUMO
We report the results of the seventh edition of the GEP-ISFG mitochondrial DNA (mtDNA) collaborative exercise. The samples submitted to the participant laboratories were blood stains from a maternity case and simulated forensic samples, including a case of mixture. The success rate for the blood stains was moderate ( approximately 77%); even though four inexperienced laboratories concentrated about one-third of the total errors. A similar success was obtained for the analysis of mixed samples (78.8% for a hair-saliva mixture and 69.2% for a saliva-saliva mixture). Two laboratories also dissected the haplotypes contributing to the saliva-saliva mixture. Most of the errors were due to reading problems and misinterpretation of electropherograms, demonstrating once more that the lack of a solid devised experimental approach is the main cause of error in mtDNA testing.
Assuntos
Artefatos , Técnicas de Laboratório Clínico/normas , Impressões Digitais de DNA/normas , DNA Mitocondrial/genética , DNA/isolamento & purificação , Manchas de Sangue , Simulação por Computador , DNA/análise , DNA/genética , DNA Mitocondrial/sangue , DNA Mitocondrial/química , Interpretação Estatística de Dados , Bases de Dados Factuais , Feminino , Medicina Legal , Marcadores Genéticos , Cabelo/química , Haplótipos , Humanos , Filogenia , Reação em Cadeia da Polimerase , Polimorfismo Genético , Gravidez , Controle de Qualidade , Padrões de Referência , Saliva/químicaAssuntos
Aberrações Cromossômicas , Diagnóstico Pré-Natal , Cromossomos Humanos Par 11 , Cromossomos Humanos Par 2 , Cromossomos Humanos Par 3 , Cromossomos Humanos Par 5 , Cromossomos Humanos Par 9 , Diagnóstico Diferencial , Feminino , Aconselhamento Genético , Humanos , Hibridização in Situ Fluorescente , Recém-Nascido , Masculino , GravidezRESUMO
PURPOSE: We updated an Uruguayan family with hereditary nonpolyposis colorectal cancer first described in 1977, incorporating knowledge of how the hMLH1 germline mutation has been established and shown to segregate in accord with the expected autosomal dominant mode of genetic transmission. METHODS: DNA-based molecular genetic testing was performed in conjunction with genetic counseling. Individuals were provided with their genetic test results, so that at-risk family members would be able to benefit from targeted management programs. RESULTS: We counseled 19 members of this kindred, 13 of whom were positive for the hMLH1 germline mutation. Specific recommendations for surveillance and management were provided. We were able to describe follow-up, including anecdotal cancer survival and pathology findings extending from the initial 1977 report of this family to the present. A remarkable sibship within this kindred was comprised of eight siblings, six of whom underwent resections for colorectal carcinoma between 1963 and 1971. Colon carcinomas before 1977 in this sibship were treated with classic hemicolectomies. Of those who had hemicolectomies for their first primary colorectal cancers, two had a second colon cancer primary, and two had a third colon cancer primary. CONCLUSIONS: Attention given to this extended family with hereditary nonpolyposis colorectal cancer has had a positive impact on the physician community in Uruguay, leading to the identification of additional families with hereditary nonpolyposis colorectal cancer.
Assuntos
Neoplasias Colorretais Hereditárias sem Polipose/genética , Proteínas Adaptadoras de Transdução de Sinal , Adulto , Idoso , Proteínas de Transporte , Neoplasias Colorretais Hereditárias sem Polipose/patologia , Neoplasias Colorretais Hereditárias sem Polipose/cirurgia , Feminino , Triagem de Portadores Genéticos , Aconselhamento Genético , Testes Genéticos , Mutação em Linhagem Germinativa/genética , Humanos , Masculino , Pessoa de Meia-Idade , Proteína 1 Homóloga a MutL , Proteínas de Neoplasias/genética , Proteínas Nucleares , Linhagem , Taxa de Sobrevida , UruguaiRESUMO
Chinese hamster ovary (CHO) cells were exposed to the restriction endonuclease AluI in the presence of 1.1 M glycerol. Chromosomal aberrations and sister chromatid exchange (SCE) were scored in first post-treatment metaphases following recovery times of 6-18 h. At all recovery times chromosomal aberrations were induced by the enzyme. In AluI-treated damaged cells significant elevations of SCE frequencies were found after recovery times of 12-18 h. These results indicate that SCE, unlike chromosomal aberrations, are induced only in late G1 and early S phase of the cell cycle. The lesions producing SCE are postulated as DNA single-strand breaks and gaps induced by AluI in canonical structures of DNA and in DNA-RNA hybrids.
