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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Express?o imuno-histoquimica da cicloxigenase-2 e p53 em cancinoma epiderm?ide oral

Goulart Filho, Jo?o Augusto Vianna 17 February 2006 (has links)
Made available in DSpace on 2014-12-17T15:32:24Z (GMT). No. of bitstreams: 1 JoaoAVGF.pdf: 1413564 bytes, checksum: f5d8ea2da8907cd551169a4091430007 (MD5) Previous issue date: 2006-02-17 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Squamous cell carcinoma is the most common malignant neoplasm in the oral cavity, accounting for more than 90% of all malignancies in this location. Cyclooxygenases (COX s) are key enzymes on arachidonic acid metabolism and prostaglandin synthesis, being expressed basically in two forms: the constitutive (COX-1) and the inducible (COX-2). Increased levels on the expression of COX-2 have been implicated in the pathogenesis tumor progression of various forms of human cancer, including oral squamous cell carcinoma, some of what suggesting a possible interaction between COX-2 and the protein expressed by the tumor suppressor gene p53, mutated in more than 50% of all human cancers. The mean of the present research consisted in analyze the correlation between the expression of COX-2 and p53, at the protein level, as well as evaluate the difference on the expression of these two proteins with the histological grading of malignancy. 34 cases of oral squamous cell carcinoma were selected and graded according to the histological grading system proposed by Bryne (1998) and the labeling indexes (LI s) for COX-2 and p53 evaluated using immunohistochemistry method. The results revealed that COX-2 was expressed in increased levels in most of the specimens, although there was no statistic significant correlation between LI s from COX-2 and p53 (p>0.05), and there were no statistical differences on the expression of these proteins between tumors of high and low grade of malignancy (p>0.05). Interestingly, the expression of COX-2 and p53 was detected in fragments of dysplastic oral epithelium adjacent to tumor areas, on basal and suprabasal layers. The absence of statistical correlation between the expression of COX-2 and p53 proteins do not rule ot the existence of a relation between them, were it may reflect the diversity of regulatory pathways between both, different direct and indirect inhibitory effects of COX-2 over p53, as well as the wide range of activation macheenisms for COX-2 and mutational status of the p53 gene Another conclusion point that the increased expression of COX-2 observed in oral squamous cell carcinomas suggest a role for this protein in the processes of pathogenesis and tumoral evolution of this malignant neoplasm / O carcinoma epiderm?ide ? a neoplasia maligna mais comum na cavidade oral, representando mais de 90% das malignidades nesta localiza??o. As cicloxigenases (COX s) s?o enzimas chave no metabolismo do ?cido aracd?nico e s?ntese de prostaglandinas, sendo expressas basicamente sob duas formas: uma constitutiva (COX-1) e uma induzida (COX-2). N?veis elevados na express?o da COX-2 t?m sido implicados na patog?nese e progress?o tumoral em diversos tipos de c?ncer em humanos, incluindo o carcinoma epiderm?ide oral, alguns dos quais sugerindo uma poss?vel intera??o entre a COX-2 e a prote?na expressa pelo gene supressor tumoral p53, mutado em mais de 50% de todos c?nceres humanos. O prop?sito da presente pesquisa consistiu em analisar a correla??o entre a express?o de COX-2 e p53, em n?vel de prote?na, bem como avaliar a diferen?a na express?o destas duas prote?nas em rela??o ao grau histol?gico de malignidade. Para tal, foram selecionados 34 casos de carcinoma epiderm?ide oral, os quais foram classificados de acordo com o sistema de grada??o histol?gica de malignidade proposto por Bryne (1998) e cujos ?ndices de positividade para COX-2 e p53 foram avaliados atrav?s da t?cnica imuno-histoqu?mica. O resultados revelaram que a COX-2 esteve expressa em n?veis elevados na maior parte dos esp?cimes analisados, embora n?o se tenha verificado correla??o estatisticamente significativa entre os IP s da COX-2 e da p53 (p>0,05), tampouco diferen?a estatisticamente significativa entre a express?o destas prote?nas entre tumores de alto e baixo grau de malignidade (p>0,05). Interessantemente, foi detectada a express?o da COX-2 e da p53 em fragmentos de epit?lio oral displ?sico, nas camadas basal e parabasal, adjacentes ao tumor. A aus?ncia de correla??o estat?stica entre a express?o das prote?nas COX-2 e p53 n?o descarta a exist?ncia de uma rela??o entre as mesmas, podendo refletir a diversidade de vias regulat?rias entre ambas, os diferentes efeitos inibit?rios diretos e indiretos da COX-2 sobre a p53, bem como os in?meros mecanismos de ativa??o da COX-2 e o estado mutacional do gene p53. Conclui-se ainda que a elevada express?o da COX-2 observada em carcinomas epiderm?ides orais sugere um papel desta prote?na dentro dos processos de patog?nese e evolu??o tumoral desta neoplasia maligna
12

Análise de polimorfismos das enzimas ciclooxigenase-2 e metilenotetrahidrofolato redutase em pacientes com câncer de esôfago / Analysis of the cyclooxygenase-2 and methylenetetrahydrofolate reductase genes polymorphisms in esophageal cancer

Evelise Pelegrinelli Zaidan 28 January 2016 (has links)
Introdução: O estudo de polimorfismos genéticos pode permitir maior conhecimento sobre os fatores de risco, progressão e susceptibilidade ao câncer do esôfago. A enzima ciclooxigenase-2 (COX-2) é induzida em resposta ao fator de crescimento e citocinas, sendo expressa nas doenças inflamatórias, lesões pré-malignas e tumores de esôfago. O produto do metabolismo do folato, pela enzima metilenotetrahidrofolato redutase (MTHFR), atua na síntese do DNA. A alteração ou a inibição da atividade desta enzima aumenta a suscetibilidade a mutações, danos e metilação aberrante do DNA, o que altera a expressão gênica de supressores de tumor e proto-oncogenes, potenciais fatores de risco para o câncer de esôfago. Objetivo: Investigar a frequência dos polimorfismos COX-2 (-1195A > G e 8473T > C) e MTHFR (677C > T e 1298C > A) em pacientes com câncer de esôfago, verificar as associações entre a frequência desses polimorfismos com a susceptibilidade à esta doença e aos fatores clínicos, epidemiológicos e patológicos. Metodologia: Inclui-se cento e nove pacientes com o diagnóstico de câncer de esôfago, submetidos à esofagectomia. Cento e dois indivíduos, pareados quanto ao sexo e idade, sem histórico individual ou familial de câncer, constituem o grupo controle. O DNA genômico foi isolado do creme leucocitário de sangue periférico e a genotipagem foi realizada através dos kits TaqMan ® SNP Genotyping Assays, seguida da amplificação pela reação em cadeia da polimerase e análise em tempo real (RT-PCR). Os resultados dos polimorfismos encontrados foram associados aos dados epidemiológicos e clinicopatológicos destes pacientes. Utilizou-se a regressão logística para avaliar as associações entre os polimorfismos e o risco de desenvolver o câncer de esôfago, com intervalos de confiança de 95%. Resultados: A presença do alelo COX-2+8437C (p=0,016) e dos haplótipos COX-21195A/COX2843C (p=0,002) e COX-21195G/COX28437T (p=0,01) indicaram associação com a doença. Os indivíduos com câncer do esôfago portadores do polimorfismo MTHFR 677TT apresentaram maior risco de óbito pela doença (p = 0,045). Conclusão: A presença do alelo COX-2+8437C e dos haplótipos COX21195A/COX2843C e COX-21195G/COX28437T associaram-se ao câncer de esôfago. O genótipo homozigoto polimórfico MTHFR677TT está relacionado ao pior prognóstico em pacientes com câncer de esôfago / Introduction: The study of genetic polymorphisms may allow better understanding of the risk factors, progression and susceptibility to cancer of the esophagus. The cyclooxygenase-2 enzyme (COX-2) is induced in response to growth factors and cytokines and is expressed in inflammatory diseases, premalignant and esophageal tumors. The product of folate metabolism, the enzyme methylenetetrahydrofolate reductase (MTHFR), engaged in DNA synthesis. Changing or inhibiting the activity of this enzyme increases the susceptibility to mutations, damage and aberrant DNA methylation, which alters gene expression of tumor suppressors and proto-oncogenes, potential risk factors for esophageal cancer. Objective: To investigate the frequency of COX-2 (-1195A > G and 8473T > C) and MTHFR (677C > T and 1298C > A) polymorphisms in patients with esophageal cancer, verify the associations between the frequency of these polymorphisms with susceptibility to this disease and clinical, epidemiological and pathological factors. Methodology: This study includes up one hundred nine patients diagnosed with esophageal cancer who underwent esophagectomy. One hundred and two individuals, matched for sex and age, no individual or familial history of cancer, constitute the control group. Genomic DNA was isolated from the peripheral blood buffy coat and genotyping was performed using the TaqMan ® SNP Genotyping Assays kits, followed by amplification by polymerase chain reaction and real-time analysis (RT-PCR). The results of found polymorphisms were associated with epidemiological and clinicopathological these patients. Logistic regression was used to assess associations between polymorphisms and the risk of developing esophageal cancer, with 95% confidence intervals. Results: The presence of COX-2 + 8437C allele (p = 0.016) and haplotypes COX-21195A / COX2843C (p = 0.002) and COX-21195G / COX28437T (p = 0.01) indicated association with the disease. Individuals with esophageal cancer carrying the MTHFR 677TT polymorphism had higher risk of death from the disease (p = 0.045). Conclusion: The presence of COX-2+8437C allele and haplotype COX21195A/ COX2843C and COX-21195G/COX28437T was associated with esophageal cancer. The polymorphic homozygous genotype MTHFR677TT is related to worse prognosis in patients with esophageal cancer

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