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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.
81

Molecular mechanisms involved in the protective effect of Mediterranean diet and olive oil consumption in humans

Konstantinidou, Valentini 22 March 2010 (has links)
The scope of the present work was to investigate whether the protective role of the traditional Mediterranean diet (TMD), and virgin olive oil (VOO) rich in phenolic compounds (PC), towards cardiovascular disease can be mediated through gene expression changes. Two trials were performed to assess the in vivo nutrigenomic effects of TMD and VOO in healthy volunteers. The results point out: a) significant gene expression changes of those genes related with cardiovascular-risk processes after VOO ingestion; b) a down-regulation in the expression of atherosclerosis-related genes after a 3-month intervention with a TMD; and c) an olive oil PC health-protective nutrigenomic effect within the frame of the TMD. Changes in gene expression were concomitant with decreases in oxidative damage and systemic inflammation markers. Data from our studies provide further evidence to recommend both the TMD and the VOO as a useful tool for the prevention of atherosclerosis. / El objetivo de este estudio es investigar si el papel protector de la dieta Mediterránea tradicional (TMD) y del aceite de oliva virgen (VOO), rico en compuestos fenólicos (PC), puede ser mediado a través de cambios en la expresión génica. Se realizaron dos ensayos clínicos para evaluar los efectos nutrigenómicos de la TMD y del VOO, in vivo, en voluntarios sanos. Los resultados mostraron a) cambios en la expresión génica de genes relacionados con el riesgo cardiovascular tras la ingestión del aceite virgen de oliva, b) una infra-expresión en la expresión de genes relacionados con el proceso aterosclerótico tras una intervención con TMD de 3 meses y c) que los compuestos fenólicos del aceite de oliva ejercen un efecto nutrigenómico protector en el marco de la TMD. Los cambios en la expresión génica fueron coherentes.
82

Avaliação da carga viral plasmática do HTLV-1 em indivíduos assintomáticos e desenvolvendo a mielopatia associada ao HTLV-1/paraparesia espástica tropical (HAM/TSP). / Evaluation of HTLV-1 plasmatic viral load in asymptomatic and HTLV-1-associated myelopathy/Tropical spastic paraparesis (HAM/TSP) individuals.

Fábio Aparecido Barbosa Cabral 05 July 2010 (has links)
O vírus linfotrópico das células T humanas tipo 1 (HTLV-1), é responsável por patologias como a mielopatia associada ao HTLV-1 ou paraparesia espástica tropical (HAM/TSP) e a leucemia/linfoma das células T do adulto (ATL) dentre outras. As vias de replicação até hoje demonstradas, não suportam a hipótese de um estado virêmico. Neste estudo, a detecção de partículas virais plasmáticas foi executada, por PCR em Tempo Real e Nested PCR em 190 amostras de pacientes infectados pelo HTLV-1(assintomáticos ou com HAM/TSP), em acompanhamento, no Instituto de Infectologia Emílio Ribas. 12 indivíduos (8%) testados por PCR em tempo real (n=150) e 6 indivíduos (18%) testados por Nested PCR (n=33, dado que sete amostras foram excluídas da análise) apresentaram RNA do HTLV-1 detectável no plasma. Em conclusão, foi possível identificar RNA plasmático do HTLV-1, tanto em pessoas assintomáticas quanto com HAM/TSP. Esta detecção abre novas possibilidades de discussão sobre a replicação do HTLV-1 e das vias de transmissão, sugerindo maiores investigações para elucidar o assunto. / The human T-cell lymphotropic virus type1 (HTLV-1) is responsible for some pathologies such as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and Adult T-cell Leukemia/ Lymphoma (ATL) among others. Its ways of replication so far presented do not support the hypothesis of a viremic stage. In this study, the detection of the plasmatic viral load was performed by real time PCR and Nested PCR in 190 samples from HTLV-1 infected individuals (Either Asymptomatic or HAM/TSP cases) following up at Instituto de Infectologia Emílio Ribas. 12 individuals (8%) tested by Real time PCR (n= 150) and 6 individuals (18%) tested by Nested PCR (n= 33, given that 7 samples were excluded from the analysis) presented detectable HTLV-1 RNA in the plasma. In conclusion, it was possible to indentify HTLV-1 plasmatic RNA in asymptomatic carriers as well as in HAM/TSP cases. This detection opens new possibilities of discussion about HTLV-1 replication and transmission pathways, suggesting further investigation for clarifying this matter.
83

Endomiocardiofibrose: patologia e correlação clínica em material de ressecção cirúrgica / Endomyocardial fibrosis: pathological findings in surgical specimens and clinicopathological correlation

Silvia D\'Andretta Iglezias 26 March 2008 (has links)
INTRODUÇÃO: A endomiocardiofibrose (EMF) é uma miocardiopatia de padrão restritivo de etiologia desconhecida, prevalente em regiões tropicais. Caracteriza-se por espessamento fibroso do endocárdio e miocárdio subjacente, comprometendo ponta e via de entrada de um ou de ambos os ventrículos. Sua etiopatogenia é pouco conhecida e muitos autores a associam à doença infecciosa cardíaca ou sistêmica, à eosinofilia prévia e/ou à carência nutricional. O prognóstico em geral é grave e a ressecção cirúrgica da lesão é indicada aos pacientes com insuficiência cardíaca refratária a tratamento clínico, em classe funcional III ou IV (NYHA). Os estudos anatomopatológicos até o momento foram realizados em material de autópsia ou de biópsia endomiocárdica. OBJETIVOS: Este estudo retrospectivo se propõe a (1) descrever os três aspectos morfológicos da lesão endocárdica (fibrose, infiltrado inflamatório e vasos) utilizando microscopia óptica comum e técnicas imunoistoquímicas, assim como correlacioná-los aos dados clínicos, laboratoriais e de imagem dos pacientes (2) comparar os aspectos morfológicos de espécimes de ressecção cirúrgica com os de autópsia a fim de verificar se os primeiros podem ser empregados para diagnóstico histológico da doença; e (3) discutir a patogenia da EMF e realizar pesquisa de agentes infecciosos cardiotrópicos em amostra endomiocárdica incluída em parafina por técnica de biologia molecular. MÉTODOS: Foram utilizadas amostras de ressecção cirúrgica endocárdica incluídas em parafina provenientes de 31 pacientes com diagnóstico clínico e cineangiocardiográfico de EMF, operados no InCor entre 1991 e 2005. As amostras foram coradas por técnicas convencionais (HE, tricômico de Masson, Verhoeff e reticulina) e submetidas a reações imunoistoquímicas para fibras colágenas tipo I, III e IV, para células inflamatórias (CD3, CD20, CD68) e para endotélio de linfáticos (D2-40). Amostras de nove corações de autópsia de pacientes com o mesmo diagnóstico serviram de controle positivo da doença. A pesquisa de agentes infecciosos foi feita por reação de cadeia de polimerase e reação de transcrição reversa de cadeia de polimerase (PCR e RT-PCR) em amostras endomiocárdicas incluídas em parafina, para T. gondii e para vírus cardiotrópicos (enterovirus, adenovirus, influenza A e B, citomegalovirus, parvovirus B19 e herpes simples). Para identificar alterações vasculares intramiocárdicas, procedeu-se à revisão de prontuários clínicos dos pacientes e de 16 cineangiocoronariografias. RESULTADOS: Foi observado intenso espessamento endocárdico ventricular à custa de fibrose hialina superficial escassamente celular, com fibras colágenas tipos I e III, predominando o tipo I sobre o III. O colágeno tipo IV foi identificado na membrana basal de vasos. Na porção profunda da lesão endocárdica observou-se escasso infiltrado inflamatório crônico com macrófagos, linfócitos T e B em menor número. O infiltrado estava distribuído ao redor de vasos proliferados com intensas alterações estruturais na parede e com participação de linfáticos. No miocárdio superficial identificou-se miocardite \"borderline\" (critério de \"Dallas\"). Foram obtidos ácidos nucléicos em quantidade suficiente para a reação de PCR/RT-PCR em 12/36 (33%) amostras. Genomas de agentes infecciosos foram identificados em 6/12 (50%) pacientes. Dois casos foram positivos para enterovirus (EV), dois para citomegalovirus (CMV), um para ambos (CMV e EV) e um para T. gondii. Não foram observadas diferenças histopatológicas entre as amostras cirúrgicas e as de autópsia. Foram detectadas alterações vasculares à cineangiocoronariografia em 9/16 (56%) pacientes. Não houve correlação anatomoclínica definida entre os múltiplos dados comparados. CONCLUSÕES: Os resultados indicam que na EMF ocorre processo inflamatório crônico mantido por rede vascular anômala rica em linfáticos localizada na profundidade da lesão endocárdica. A rede vascular provavelmente contribui para a manutenção da placa fibrótica e deve ser considerada como fator importante na patogenia da doença. O diagnóstico anatomopatológico pode ser feito com segurança em material de ressecção cirúrgica. A análise molecular do endomiocárdio possibilitou a detecção de alta incidência de genomas de agentes infecciosos cardiotrópicos. Seu significado, contudo, permanece controverso. / BACKGROUND: Endomyocardial fibrosis (EMF) is a restrictive cardiomyopathy of unknown etiology prevalent in tropical regions. The disease involves the inflow tract and apex of either one or both ventricles and is characterized by a fibrous thickening of the endocardium and the underlying myocardium. Although its etiology remains unknown, most authors believe it could be related to systemic or heart infection/parasitism, previous blood eosinophilia or malnutrition. Surgical resection of the thickened endocardium is recommended to patients with advanced heart failure of functional class III or IV, New York Heart Association (NYHA). The gross and histological features of the heart have been comprehensively studied in autopsies and endomyocardial biopsies. Studies in surgical samples, however, are still lacking. AIMS: This study was conducted to evaluated: (1) the histomorphological changes of EMF as seen in surgical specimens by means of routine histological and immunohistochemical methods in an attempt to correlate them with clinical symptoms and coronary angiographic features; (2) to compare histological data between surgical and autopsy samples, and (3) to discuss probable pathogenetic mechanisms of the disease, as well as to investigate cardiotropic infective agents by means of molecular analysis of endomyocardial surgical samples. METHODS: We collected all available clinical records and endomyocardial surgical samples from 31 patients with EMF who had been submitted to surgery between 1991 and 2005 at InCor. The diagnosis was based on clinical, hemodynamic and angiocardiographic findings. The surgical samples were fixed in 10% formalin, submitted to standard processing, and stained with H&E, Masson\'s trichrome, reticulin and elastic stains. Immunohistochemical methods were employed to detect collagen fibers type I, III, and IV, inflammatory cells (CD3, CD20, CD68) and lymphatic vessels\' endothelium (D2-40). Nine samples from autopsied hearts of EMF patients were used as a positive control group. Polymerase chain reaction (PCR) and reverse transcription-PCR were used retrospectively to search for genomes of T. gondii and cardiotropic viruses (enterovirus, adenovirus, influenza A e B, cytomegalovirus, parvovirus B19 and herpes simplex) in the surgical material. All clinical and surgical reports were reviewed, including follow-ups and 16 coronary cineangiocardiographies. RESULTS: Ventricular endocardium was thickened by superficial acellular hyaline collagen fibers type I and III. Type-IV collagen fibers were seen only around vessels. Focal chronic inflammatory infiltrate with T-lymphocytes, macrophages and a few B-lymphocytes was seen around blood vessels with a peculiar pattern of vascular changes and numerous lymphatics within the endocardium. The superficial myocardium showed borderline myocarditis (Dallas criteria). RNA and DNA were successfully extracted from 12/36 samples. Infective agents were detected in 6/12 (50%) patients; two of them were positive for cytomegalovirus (CMV), two for enterovirus (EV), one for both (CMV and EV) and one for T. gondii. No histopathological differences between surgical samples and autopsy fragments were observed. Vascular blush or neovascularity was detected in 9 of the 16 coronary cineangiocardiographies reviewed. Clinicopathologic characteristics are associated neither with infective genomes in the endocardium nor with vascular blush. CONCLUSIONS: Results indicate that there is an non especific chronic inflammatory process maintained by an anomalous vascular net rich in lymphatics situated deep within the endocardium. This angiolymphatic web probably contributes to the maintenance of the fibrotic plaque and might be considered an important pathological finding concerning in the pathogenesis of EMF. Histopathological changes as seen in surgical material are diagnostic of EMF. Molecular analysis of the endomyocardium revealed high incidence of cardiotropic infective agents, but their role in the pathogenesis of the disease is still controversial.
84

Cell-free fetal DNA (cffDNA) enrichment for non-invasive prenatal testing (NIPT) : a comparison of molecular techniques

Sillence, Kelly January 2016 (has links)
Prenatal assessment of fetal health is routinely offered throughout pregnancy to ensure that the most effective management can be provided to maintain fetal and maternal well-being. Currently, invasive testing is used for definitive diagnosis of fetal aneuploidy, which is associated with a 1% risk of iatrogenic fetal loss. Developing non-invasive prenatal testing (NIPT) is a key area of research and methods to increase the level of cell-free fetal DNA (cffDNA) within the maternal circulation have been discussed to improve accuracy of such tests. In this study, three strategies; co-amplification at lower denaturation temperature polymerase chain reaction (COLD-PCR), inverse-PCR and Pippin Prep™ gel electrophoresis, were analysed to identify a novel approach to selectively enrich shorter cffDNA fragments from larger maternal cell-free DNA (cfDNA). The sensitivity of droplet digital PCR (ddPCR) against real-time PCR (qPCR) was compared for fetal sex and RHD genotyping. In addition RHD zygosity testing was carried out for non-maternal samples. Consequently, Pippin Prep™ gel electrophoresis was combined with ddPCR analysis for the NIPD of Down Syndrome (DS) in pseudo-maternal samples. The results revealed that the Pippin Prep™ gel electrophoresis enrichment approach successfully demonstrated 2-fold to 5-fold increases in the cffDNA fraction. However, further optimisation assays of COLD-PCR and inverse-PCR using actual maternal samples were required. The spike experiments for DS detection revealed that with the present assay IV overrepresentation of the chromosome 21 target could be significantly detected for samples with ≥15% ‘cffDNA fraction’. In conjunction with the Pippin Prep™ enrichment method, this would have enabled assessment of all 10 maternal samples. Alternatively, fetal sex and RHD genotyping results determined that ddPCR provides a more sensitive platform compared to qPCR approaches, particularly for samples that express low cffDNA fractions (<2%). The ddPCR platform also proved to be a rapid and accurate system for the determination of RHD zygosity. This study highlights that ddPCR could be used as opposed to qPCR for accurate determination of fetal sex and RHD status. While sequencing approaches currently provide the most sensitive platforms for NIPT of fetal aneuploidy, high costs (>£400) prevent universal application. The combination of cffDNA enrichment with ddPCR analysis could provide a cheaper and more widely available platform for NIPD. However, further large scale validation studies using actual maternal samples are required.
85

Prospecção de genes biossintéticos de policetídeos a partir de fungos isolados de cana-de-açúcar. / Screening of polyketides biosynthetic genes from sugarcane derived fungi.

Juan Diego Rojas Rojas 03 November 2010 (has links)
A partir de 280 isolados fúngicos de cana-de-açúcar, 18 cepas foram avaliadas quanto á presença de genes da policetídeo sintase por meio da técnica do PCR. Estes fungos foram identificados taxonomicamente por uma abordagem polifásica, classificando-os dentro de quatro ordens e nove gêneros. A avaliação da atividade biológica demonstrou a presença de metabolitos com propriedades antibióticas quando enfrentados a micro-organismos patogênicos. Segundo a análise de correspondência múltipla, esta atividade poderia estar associada com a local de isolamento dos fungos. Foram detectadas 36 seqüências similares a genes PKS a partir de 17 destes fungos. A análise filogenética do domínio KS, conduzida pelo método de neighbor-joining, indicou que 16 seqüências se acomodaram dentro do grupo monofilético dos PKS envolvidos na produção de policetídeos não reduzidos e as outras 10 seqüências se acomodaram dentro do grupo monofilético dos PKS envolvidos na produção de policetídeos reduzidos. A análise do domínio CMT também apontou que as seqüências podiam se acomodaram em grupos de PKS dependendo do grau de redução do policetídeo, todas as seqüências CMT se relacionaram com PKS envolvidos na produção de policetídeos reduzidos. As análises dos modelos estruturais também demonstraram que as seqüências estavam altamente relacionadas com estruturas protéicas da família das enzimas de condensação, destacando a presença de uma hélice característica que carrega o resíduo de cisteína, responsável pela atividade de condensação. Extratos orgânicos obtidos de cultivos dos fungos foram avaliados parar detectar a presença de compostos tipo lovastatina. Por meio de cromatografia CCDS, detectaram-se bandas de 10 extratos com o mesmo deslocamento que a lovastatina padrão, mas apenas 6 destas foram confirmados por CLAE. O isolado A. flavus CBMAI 1023, foi selecionado para a realização de experimentos de produção a maior escala onde foi possível isolar e caracterizar um novo policetídeo. / From a group of 280 sugarcane-derived fungi 18 strains were assessed for the presence of polyketide synthase genes by PCR approaches. These fungi were identified taxonomically by a polyphasic approach classifying into four orders and nine genres. Biological activity tests showed the presence of antibiotic metabolites against pathogenic microorganisms and the relationship of this activity might be linked with the fungal isolate location by multiple correspondence analyses. 36 sequences similar to PKS genes fragments were detected from 17 of these fungi. A neighbor-joining phylogenetic analysis of the KS domain showed that 16 sequences fit on the monophyletic group of PKS evolved with production of non reduced polyketides, and the other 10 sequences fit on the monophyletic group of PKS evolved with the production of reduced polyketides. CMT domain analysis also pointed that the sequences fit with groups of PKS depending on polyketide reduction grade, all ten related to PKS evolved with the synthesis of reduced polyketides. Protein structural analysis also pointed out that these sequences are closely related with proteins from condensing enzyme family, highlighting the presence of a characteristic helix elbow that bears the cysteine residue responsible for the condensation activity. The fungi were also tested for their capacity of producing lovastatin compounds where chromatographic TLC detected bands from 10 extracts with the same dislocation compared to a lovastatin, but only 6 were confirmed by HPLC. The A. flavus CBMAI (1023) were selected for upscale production experiments, from where it was possible isolate and characterize a new polyketide compound.

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