Navegando por Assunto "Polimorfismo de DNA"

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Acesso aberto (Open Access)
Alterações genéticas e epigenéticas em meningiomas na população paraense
(Universidade Federal do Pará, 2013-07-17) BASTOS, Carlos Eduardo Matos Carvalho; ANSELMO, Nilson Praia; http://lattes.cnpq.br/6518287721873199; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093
Meningiomas are the most common intracranial tumors that originate from the meninges surrounding the brain and spinal cord. Despite meningiomas were among the first solid neoplasms to be studied cytogenetically, little is known about their genetic and epigenetic profile. This study aimed to investigate genetic and epigenetic alterations that could contribute to tumor initiation and progression in meningiomas in the population of Pará, Brazil. This thesis is subdivided into three chapters. In Chapter I we investigated the association between the MTHFR C677T and meningioma in 23 patients in the population of Pará. A total of 96 healthy individuals with no previous pre-neoplastic lesions were selected for the control group. This association was not found. Although not statistically significant, our observation suggests that the TT genotype increases the risk of developing meningioma when compared to CC genotype. In Chapter II we evaluated the methylation pattern in two members of microRNA124 family in meningiomas in the population of Pará. Hypermethylation of the promoter region of miRN124a2 and miRNA124a3 appears to be a frequent event, as was found in 73.9% and 69.56% of the samples, respectively. In Chapter III, we analyzed the methylation pattern of the APC, BRCA1, CDH1, CDH13, CDKN2A, DAPK1, ESR1, FHIT, GSTP1, MGMT, MLH1, NEUROG1, PDLIM4, PTEN, Rb, RASSF1, RUNX3, SOCS1, TIMP3, TP73, VHL and WIF1 genes in a grade I and in a grade II meningiomas through an assay developed by MethylScreen. Pattern of methylation of CDKN2B was also analyzed in 25 patients with meningioma through bisulfite conversion, PCR and direct sequencing. RASSF1A was methylated in 16.73% and 63.66% of the CpG sites analyzed in the grade I and grade II meningioma, respectively. RUNX3 is methylated only in grade II meningioma in 52.88% of the CpG sites analyzed. Our results point to the importance of epigenetic changes in tumorigenesis and tumor progression in meningiomas.
Acesso aberto (Open Access)
Origin of the hemoglobin S gene in a northern Brazilian population: the combined effects of slave trade and internal migrations
(1998-12) SOUSA, Gabriella Pante de; RIBEIRO, Rita de Cassia Mousinho; SANTOS, Eduardo José Melo dos; ZAGO, Marco Antonio; GUERREIRO, João Farias
We analyzed DNA polymorphisms in the b-globin gene cluster of 30 sickle cell anemia patients from Belém, the capital city of the State of Pará, in order to investigate the origin of the bS mutation. Sixty-seven percent of the bS chromosomes were Bantu type, 30% were Benin type, and 3% were Senegal type. The origin of the bS mutation in this population, estimated on the basis of bS-linked haplotypes, contradicts the historical records of direct slave trade from Africa to the northern region of Brazil. Historical records indicate a lower percentage of people from Benin. These discrepancies are probably due to domestic slave trade and later internal migrations, mainly from northeastern to northern regions. Haplotype distribution in Belém did not differ significantly from that observed in other Brazilian regions, although historical records indicate that most slaves from Atlantic West Africa, where the Senegal haplotype is prevalent, were destined for the northern region, whereas the northeast (Bahia, Pernambuco and Maranhão) was heavily supplied with slaves from Central West Africa, where the Benin haplotype predominates.