Teses em Neurociências e Biologia Celular (Doutorado) - PPGNBC/ICB

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2390

O Doutorado Acadêmico pertence ao Programa de Pós-Graduação em Neurociências e Biologia Celular (PPGNBC) do Instituto de Ciências Biológicas (ICB) da Universidade Federal do Pará (UFPA).

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Navegando Teses em Neurociências e Biologia Celular (Doutorado) - PPGNBC/ICB por Orientadores "NAGAMACHI, Cleusa Yoshiko"

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    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.
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    Caracterização cromossômica e mapeamento genômico comparativo de Oecomys paricola e Oecomys auyantepui com sondas de Hylaeamys megacephalus (Cricetidae – Sigmodontinae)
    (Universidade Federal do Pará, 2015-05-19) ROSA, Celina Coelho da; NAGAMACHI, Cleusa Yoshiko; http://lattes.cnpq.br/8887641213110093
    The Order Rodentia represents the largest mammal order, with approximately 42% of species currently known. Rodents have 2,227 species, 468 genera and 33 families recent, the latter being raised to 50 if the extinct families are considered. Their huge variation in morphology, diversity of habitats and climates and food are the causes of this be most numerous and evolutionarily successful among mammalian orders. The Oecomys genus belongs to the subfamily Sigmodontinae (Cricetidae, Rodentia) with approximately 16 described species, distributed in tropical and subtropical forest of Central and South America. Previous cytogenetic studies suggest that Oecomys features large karyotype diversity, with the diploid number ranging from 58 to 86. In this study were analyzed by conventional cytogenetic techniques and multidirectional chromosome painting (using whole chromosome probes of Hylaeamys megacephalus) 18 specimens of Oecomys were analyzed, four were collected in the metropolitan area of Belém, Pará; two in the city of Santa Barbara, Pará; five in the region of Carajás, Pará and 7 in Calha Norte region, Pará. Specimes from Belém Environmental Park had 2n = 72 and FN = 76; specimes from Santa Barbara had 2n = 70 and FN = 74; from Carajás presented 2n = 70 and FN = 72. All this sample was identified as O. paricola. Specimens collected from the Calha Norte region had 2n = 62 and NF = 80 and were identified as O. auyantepui. The cytotypes described for O. paricola showed differences in five HME peaks, indicating 3 associations for this species. O. auyantepui showed five associations. Chromosomal differences found for O. paricola from different geographic regions suggest that these cytotypes belong to cryptic species. We suggest that these populations of O. paricola are a complex of species where the chromosomal differentiation already happened but not the morphological and molecular ones.
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