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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.
1

Instabilidade do Genoma Mitocondrial em Adenoma e Adenocarcinoma Colorretal. / Mitochondrial Genomic Instability in Colorectal Adenomas and Adenocarcinoma.

Araujo, Luiza Ferreira de 30 April 2013 (has links)
A mitocôndria é a organela citoplasmática responsável pelo maior sistema produtor de energia, a fosforilação oxidativa (OXPHOS). Foi proposto que em células tumorais a hiper-regulação da glicólise em condições normais de oxigênio (Efeito Warburg), está associada a defeitos na OXPHOS e pode regular o fenótipo tumoral, por exemplo, o potencial metastático da célula por meio da indução de vias pseudohipóxicas durante a normóxia. Estudos recentes mostraram que vários tipos de tumores possuem mutações somáticas em seu genoma mitocondrial, o que pode alterar as funções da OXPHOS levando a troca de metabolismo energético nas células tumorais e induzindo a tumorigênese. Diante disto, o presente trabalho avaliou a instabilidade do genoma mitocondrial em etapas bem definidas da progressão do câncer colorretal. O DNA genômico foi extraído de amostras de adenoma, adenocarcinoma, tecido adjacente e sangue periférico de nove pacientes diagnosticados com Câncer colorretal. O genoma mitocondrial foi amplificado e sequenciado para que fossem feitas as buscas por mutações nas amostras de sangue periférico, adenomas e adenocarcinoma. Foi também medido o número de cópias relativas do mtDNA. Foram encontradas um total de 233 mutações, das quais 162 foram em comum entre os três tecidos avaliados. As amostras de adenocarcinoma foram as que apresentaram uma maior média de mutações por amostra (44,6), seguidas dos adenoma (40,2) e do sangue periférico (34). As amostras de adenocarcinoma apresentaram uma maior instabilidade do mtDNA refletidas a partir de um maior número de mutações somáticas (tanto do tipo InDel como mutações de uma única base), mutações não sinônimas com maior patogenicidade, maior número de mutações em heteroplasmia e com taxa de heteroplasmia elevada. Já as amostras de adenoma apresentaram instabilidade dos seus mtDNA intermediários entre o tecido não tumoral e tumoral, refletindo bem a etapa de modificação celular no qual esses tecidos se encontram. Na análise do número de cópias relativas, as amostras de adenocarcinoma tiveram diminuição no número de cópias relativas quando comparadas com tecido adjacente (p= 0,01) e com adenomas (p= 0,04). Em síntese, o presente trabalho sugere que a instabilidade do genoma mitocondrial parece ter um papel importante no desenvolvimento de tumores colorretais. / The mitochondrion is a cytoplasmic organelle responsible for the major energy producing system, which is the oxidative phosphorylation enzyme pathway (OXPHOS). It was proposed that glycolysis up-regulation during normal oxygen conditions (Warburg effect) may induce defects in the mitochondrial respiration and regulate tumoral phenotypes, for example, metastatic potential through the induction of pseudohipoxic pathways during normoxia. Recent studies have shown that many kinds of tumors have mtDNA somatic mutations, which could alter the OXPHOS functions, leading to changes in glucose metabolismo and improvind tumorigenesis. This study analyzed the mitochondrial genome instability of well defined stages of colorectal cancer. Genomic DNA was extracted from adenoma, adenocarcinoma, adjacente tissue and peripheral blood of patients diagnosed with Colorectal cancer. The mitochondrial genome was amplified and sequenced for mutations screening in adenoma, adenocarcinoma e blood samples. It was also analyzed the relative mtDNA copy number. It was find a total of 233 mutations, which 162 were in common among the three analyzed tissues. The adenocarcinoma samples presented a greater mutation mean per sample (44.6) followed by adenomas samples (40.2) and blood samples (34). The adenocarcinoma samples also shown a greater mitochondrial genome instability refleted by increased of somatic mutations (InDels and single nucleotide variation), non sinonimous mutations with higher patogenicity, increased number of heteroplasmatic mutations and higher heteroplasmatic levels. The adenoma samples showed intermadiate instability of its mtDNA, which well reflects the intermediate stage of cellular modifications of this tissue. The mtDN copy number analysis shown that the adenocarcinoma samples presented decreased number of mtDNA content when compared with adjacente tissue (p= 0.01) and adenoma samples (p= 0.04). In summary the presente study suggests that the mitochondrial genomic instability seems to play an importante role in colorectal tumorigenesis.
2

Studies on the Chemical Constituents from the Formosan Corals Rumphella antipathies and Echionmuricea sp.

Chung, Hsu-Ming 14 February 2012 (has links)
In the interest of identifying natural substances from marine invertebrates collected off the waters of Taiwan, we have searched the bioactive metabolites from the organic extracts of gorgonian corals Rumphella antipathies and Echinomuricea sp. This study had led to the isolation of thirty compounds (1¡V30), including nine new caryophyllane-related metabolites, rumphellaones A (1), B (2) and C (3), rumphelloic acids A (4) B (5) and C (6), rumphellolides J (7), K (8) and L (9), five new clovane-related metabolites, rumphellclovanes A (12), B (13), C (14), D (15) and E (16), two new disesquiterpenoid dimers, rumphelladimers A (24) and B (25), eight new natural products, (8R,9R)-isocaryolane-8,9-diol (10), 4£],8£]-epoxycaryophyllan-5-ol (11), 9£\-hydroxyclovan-2-one (17), 2£]-hydroxyclovan-9-one (18), clovan-2,9-dione (19), 2£]-acetoxyclovan-9£\-ol (20), 9£\-acetoxyclovan-2£]-ol (21) and 2£],9£]-dihydroxyclovane (22), along with a known compound, clovan-2£],9£\-diol (23) from Rumphella antipathies. In addition, three new labdane-, halimane-, and clerodane-related metabolites, echinolids A (26), B (27) and C (28), a new sesquiterpenoid natural product, (7S,10R)-(+)-10,11-epoxycurcuphenol (29), along with a known compound, (+)-curcuphenol (30) were also found in Echinomuricea sp. The structures of metabolites 1¡V30 were established by spectroscopic methods and by comparison of the spectral data with those of related known compounds. The absolute configurations of clovane-type compounds were determined using a modified Mosher¡¦s method for 23. The biosyntheses of compounds 1¡V5 and 12 were proposed. In the biological activity experiments, compounds 5 and 19 displayed significant inhibitory effects on superoxide anion generation and elastase release by human neutrophils in response to FMLP/CB. Compounds 24 and 27 displayed significant inhibitory effects on elastase release by human neutrophils. Compound 27 was found to exhibit inhibition against the growth of DLD-1 (human colon adenocarcinoma) and Lovo (human colorectal adenocarcinoma) tumor cells.
3

Instabilidade do Genoma Mitocondrial em Adenoma e Adenocarcinoma Colorretal. / Mitochondrial Genomic Instability in Colorectal Adenomas and Adenocarcinoma.

Luiza Ferreira de Araujo 30 April 2013 (has links)
A mitocôndria é a organela citoplasmática responsável pelo maior sistema produtor de energia, a fosforilação oxidativa (OXPHOS). Foi proposto que em células tumorais a hiper-regulação da glicólise em condições normais de oxigênio (Efeito Warburg), está associada a defeitos na OXPHOS e pode regular o fenótipo tumoral, por exemplo, o potencial metastático da célula por meio da indução de vias pseudohipóxicas durante a normóxia. Estudos recentes mostraram que vários tipos de tumores possuem mutações somáticas em seu genoma mitocondrial, o que pode alterar as funções da OXPHOS levando a troca de metabolismo energético nas células tumorais e induzindo a tumorigênese. Diante disto, o presente trabalho avaliou a instabilidade do genoma mitocondrial em etapas bem definidas da progressão do câncer colorretal. O DNA genômico foi extraído de amostras de adenoma, adenocarcinoma, tecido adjacente e sangue periférico de nove pacientes diagnosticados com Câncer colorretal. O genoma mitocondrial foi amplificado e sequenciado para que fossem feitas as buscas por mutações nas amostras de sangue periférico, adenomas e adenocarcinoma. Foi também medido o número de cópias relativas do mtDNA. Foram encontradas um total de 233 mutações, das quais 162 foram em comum entre os três tecidos avaliados. As amostras de adenocarcinoma foram as que apresentaram uma maior média de mutações por amostra (44,6), seguidas dos adenoma (40,2) e do sangue periférico (34). As amostras de adenocarcinoma apresentaram uma maior instabilidade do mtDNA refletidas a partir de um maior número de mutações somáticas (tanto do tipo InDel como mutações de uma única base), mutações não sinônimas com maior patogenicidade, maior número de mutações em heteroplasmia e com taxa de heteroplasmia elevada. Já as amostras de adenoma apresentaram instabilidade dos seus mtDNA intermediários entre o tecido não tumoral e tumoral, refletindo bem a etapa de modificação celular no qual esses tecidos se encontram. Na análise do número de cópias relativas, as amostras de adenocarcinoma tiveram diminuição no número de cópias relativas quando comparadas com tecido adjacente (p= 0,01) e com adenomas (p= 0,04). Em síntese, o presente trabalho sugere que a instabilidade do genoma mitocondrial parece ter um papel importante no desenvolvimento de tumores colorretais. / The mitochondrion is a cytoplasmic organelle responsible for the major energy producing system, which is the oxidative phosphorylation enzyme pathway (OXPHOS). It was proposed that glycolysis up-regulation during normal oxygen conditions (Warburg effect) may induce defects in the mitochondrial respiration and regulate tumoral phenotypes, for example, metastatic potential through the induction of pseudohipoxic pathways during normoxia. Recent studies have shown that many kinds of tumors have mtDNA somatic mutations, which could alter the OXPHOS functions, leading to changes in glucose metabolismo and improvind tumorigenesis. This study analyzed the mitochondrial genome instability of well defined stages of colorectal cancer. Genomic DNA was extracted from adenoma, adenocarcinoma, adjacente tissue and peripheral blood of patients diagnosed with Colorectal cancer. The mitochondrial genome was amplified and sequenced for mutations screening in adenoma, adenocarcinoma e blood samples. It was also analyzed the relative mtDNA copy number. It was find a total of 233 mutations, which 162 were in common among the three analyzed tissues. The adenocarcinoma samples presented a greater mutation mean per sample (44.6) followed by adenomas samples (40.2) and blood samples (34). The adenocarcinoma samples also shown a greater mitochondrial genome instability refleted by increased of somatic mutations (InDels and single nucleotide variation), non sinonimous mutations with higher patogenicity, increased number of heteroplasmatic mutations and higher heteroplasmatic levels. The adenoma samples showed intermadiate instability of its mtDNA, which well reflects the intermediate stage of cellular modifications of this tissue. The mtDN copy number analysis shown that the adenocarcinoma samples presented decreased number of mtDNA content when compared with adjacente tissue (p= 0.01) and adenoma samples (p= 0.04). In summary the presente study suggests that the mitochondrial genomic instability seems to play an importante role in colorectal tumorigenesis.
4

Automated Gland Detection in Colorectal Histopathological Images

Al Zorgani, Maisun M., Mehmood, Irfan, Ugail, Hassan 25 March 2022 (has links)
No / Clinical morphological analysis of histopathological specimens is a successful manner for diagnosing benign and malignant diseases. Analysis of glandular architecture is a major challenge for colon histopathologists as a result of the difficulty of identifying morphological structures in glandular malignant tumours due to the distortion of glands boundaries, furthermore the variation in the appearance of staining specimens. For reliable analysis of colon specimens, several deep learning methods have exhibited encouraging performance in the glands automatic segmentation despite the challenges. In the histopathology field, the vast number of annotation images for training the deep learning algorithms is the major challenge. In this work, we propose a trainable Convolutional Neural Network (CNN) from end to end for detecting the glands automatically. More specifically, the Modified Res-U-Net is employed for segmenting the colorectal glands in Haematoxylin and Eosin (H&E) stained images for challenging Gland Segmentation (GlaS) dataset. The proposed Res-U-Net outperformed the prior methods that utilise U-Net architecture on the images of the GlaS dataset.

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