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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.
551

Ressecção endoscópica versus cirúrgica do câncer colorretal precoce: revisão sistemática e metanálises / Surgical versus endoscopic resection of early colorectal cancer: systematic review and meta-analysis

Silva, Gustavo Luis Rodela 04 December 2018 (has links)
INTRODUÇÃO: O câncer colorretal (CCR) é doença de grande importância, com elevada incidência e mortalidade. Restrito às camadas mucosa e submucosa, é denominado CCR precoce, sendo passível de tratamento endoscópico curativo na ausência de fatores de risco para metástases linfonodais. Entretanto, as técnicas para tal não são universalmente disponíveis, e muitos destes pacientes são tratados por ressecções cirúrgicas. OBJETIVO: Buscar estudos com os resultados do tratamento cirúrgico e endoscópico do CCR precoce e compará-los por meio de metanálise. MÉTODOS: Foi efetuada busca nas bases MEDLINE, EMBASE, LILACS, CENTRAL COCHRANE e EBSCO por estudos comparativos que incluíram pacientes com CCR precoce, submetidos a tratamento endoscópico ou cirúrgico. Dados de mortalidade, recidiva a longo prazo, taxas de ressecção em bloco e ressecção curativa, tempo de procedimento, taxas de complicações e complicações graves foram extraídos. Viés foi individualmente avaliado pela escala de Newcastle-Ottawa. Foram efetuados cálculos do risco absoluto (RA), seu aumento (ARA) ou redução (RAA), e dos números necessários para causar dano (NNH) ou tratar (NNT), com intervalo de confiança (IC) de 95% para significância estatística. Para metanálise dos dados, foi utilizado o programa RevMan 5, com uso do teste de Mantel-Haenszel para calcular um IC de 95%, e expressão dos resultados em gráficos de forest e funnel plot. A consistência entre os estudos foi relatada por I2. RESULTADOS: Foram encontradas 12.905 entradas via PUBMED e 12.818 via outras bases. Após remoção de duplicatas e aplicação dos critérios de inclusão e exclusão, restaram quatro estudos de coorte retrospectiva. Não foi observada diferença para mortalidade (339 pacientes) ou recorrência a longo prazo (577 pacientes). Foi observada superioridade do tratamento cirúrgico em 11% (-0,11 [IC 95% -0,14; -0,09, P < 0,05]) para taxa de ressecção em bloco (1.085 pacientes), e em 11% (-0,11 [IC 95% -0,21; -0,02, P < 0,05]) para taxa de ressecção curativa (1.112 pacientes). O tratamento endoscópico demonstrou superioridade de 7% (-0,07 [IC 95% -0,10; -0,03]) para taxa de complicações (1.085 pacientes), de 8% (-0,08 [IC 95% -0,15; -0,01]) para complicações graves (827 pacientes), e de 130 minutos (-130,34 [IC 95% -190,5; -70,17, P < 0,05) para tempo de procedimento (827 pacientes). CONCLUSÃO: Conforme os dados disponíveis na literatura, o tratamento do CCR precoce apresenta melhores resultados pela técnica cirúrgica quanto às taxas de ressecção em bloco e curativa, e menos complicações e menor tempo de procedimento pela técnica endoscópica. Não há diferença quanto às taxas de mortalidade e recidiva a longo prazo / INTRODUCTION: Colorectal cancer (CRC) represents an important disease, with high incidence and mortality. When restricted to the mucosa and submucosa it is called early CRC, with curative endoscopic treatment in the absence of histopathological conditions associated with high risk of linfonodal metastasis. However, such treatment techniques are not widely available, and many of these patients undergo surgical resection. OBJECTIVES: To search for studies of endoscopic and surgical treatment modalities for early CRC, and compare these results through meta-analysis. METHODS: MEDLINE, EMBASE, LILACS, CENTRAL COCHRANE, and EBSCO databases were searched for comparative studies, which included early CRC patients subjected to surgical or endoscopic treatments. Data regarding mortality, recurrence, en bloc resection rate, curative resection rate, procedure time, complications rate, and severe complications rate were extracted. Study bias was evaluated using the Newcastle-Ottawa score. Absolute Risk (AR), AR reduction (ARR), AR increase (ARI), and the number necessary to treat (NNT) or to harm (NNH) were computed, using a 95% confidence interval (CI) as statistically significant. RevMan 5 software was used for meta-analysis, applying Mantel-Haenszel tests to achieve a 95% CI; results were represented by forest and funnel plots. Consistency among studies was reported via I2. RESULTS: 12,905 entries were found via PUBMED, and 12,818 via other databases. After removal of duplicates and observation of inclusion and exclusion criteria, 4 retrospective cohort studies were considered for analysis. No differences in mortality (339 patients) and long-term recurrence (577) were observed between the two groups. Surgical treatment had higher rates of en bloc resection (-0.11 [95% CI -0.14, -0.09, P < 0.05] - 1,085 patients) and curative resection (-0.11 [IC 95% CI -0.21, - 0.02, P < 0.05] - 1,112 patients) when compared to endoscopic treatment. Endoscopic treatment had lower total complication rate (0.07 [IC 95% -0.10; - 0.03] - 1,085 patients), lower severe complication rate (-0.08 [IC 95% -0.15; - 0.01] - 827 patients), and shorter procedure time than the surgical treatment (-130.34 min [IC 95% -190.5; -70.17, P < 0.05] - 827 patients). CONCLUSION: According to available data, surgical treatment of early CRC yields better results regarding en bloc resection and curative resection rates; endoscopic treatment of early CRC results in lower complication rate and shorter procedure time. There are no differences in mortality and long-term recurrence rates
552

Investigação do microbioma intestinal em camundongos deficientes em CRAMP submetidos à sepse experimental / Investigation of the intestinal microbiome in mice deficient in CRAMP subjected to experimental sepsis

Almeida, Marta Lucia de 05 December 2018 (has links)
O microbioma intestinal tem sido associado à sepse, causada por infecção, apresentando respostas imunológicas exacerbadas. O peptídeo antimicrobiano CRAMP atua na imunidade inata com característica ambígua, ora pró-inflamatória ora anti-inflamatória. Nesse estudo, a sepse foi induzida por modelo de ligadura e punção cecal (CLP) e, através de RT-qPCR, o DNA de amostras fecais de camundongos selvagens e deficientes em CRAMP foi analisado. A expressão de Alfa-defensina 5 e Beta-defensina 1 foi investigada em RT-qPCR. Técnicas de imunofluorescência, Elisa e Milliplex, foram utilizadas na quantificação de citocinas - IL-1Beta, IL-6, IL-10, MCP-1 e TNF-Alfa -, e Alfa-defensina 7 e Beta-defensina 1. Os resultados mostraram a intensificação da resposta imune, diante da sepse, com alterações pró-inflamatórias de IL-1Beta, IL-6, MCP-1 e TNF-Alfa e anti-inflamatória de IL-10. A Beta-defensina 1 teve expressão aumentada, enquanto a produção foi mantida ou reduzida nos tecidos, após CLP. A liberação de Alfa-defensina 7 foi ampliada no pulmão de animais selvagens durante a sepse, enquanto a expressão de Alfa-defensina 5 foi reduzida no íleo e cólon. A relação entre o microbioma intestinal e a sepse evidenciou-se com o crescimento da espécie Escherichia coli, enquanto o CRAMP apresentou associação com a espécie Bacteroides vulgatus. Novos estudos permitiram mais conhecimento sobre a interação entre sepse e microbioma intestinal, potencializando o uso de biomarcadores e nova terapêutica na recuperação intestinal, tal como transplante microbiológico fecal / The intestinal microbiome has been associated with sepsis, caused by infection, presenting exacerbated immune responses. The antimicrobial peptide CRAMP acts on innate immunity with ambiguous features, pro-inflammatory and anti-inflammatory. In this study, sepsis was induced by cecal ligation and puncture (CLP) model and, through RT-qPCR, the DNA of fecal samples from wild type and CRAMP-deficient mice was analyzed. Expression of Alpha-defensin 5 and Beta-defensin 1 was investigated in RT-qPCR. Immunofluorescence techniques, Elisa and Milliplex, were used to quantify cytokines - IL-1Beta, IL-6, IL-10, MCP-1 and TNF-Alpha -, and Alpha-defensin 7 and Beta-defensin 1. The results showed the enhancement of the immune response to sepsis with proinflammatory alterations of IL-1Beta, IL-6, MCP-1 and TNF-Alpha and anti-inflammatory IL-10. CRAMP and Beta-defensin 1 peptides had increased expression, while production was maintained or reduced in tissues after CLP. The release of Alpha-defensin 7 was amplified in the lungs of wild type animals during sepsis, while expression of Alpha-defensin 5 was reduced in the ileum and colon. The relationship between the intestinal microbiome and sepsis was evidenced by the growth of Escherichia coli, while CRAMP was associated with Bacteroides vulgatus. New studies have allowed more knowledge about the interaction between sepsis and intestinal microbiome, potentializing the use of biomarkers and new therapy in intestinal recovery, such as fecal microbiological transplantation
553

Cromoscopia óptica com tecnologia de banda estreita versus cromoscopia com solução de Lugol no diagnóstico do carcinoma superficial de esôfago em pacientes com câncer de cabeça e pescoço / Narrow band imaging versus chromoendoscopy with Lugols solution for esophageal squamous cell carcinoma detection

Ide, Edson 22 July 2010 (has links)
Presente estudo teve como objetivo avaliar a utilização da tecnologia de banda estreita com filtros ópticos (TBE) no rastreamento do carcinoma espinocelular do esôfago (CEC), utilizando como método comparativo a cromoscopia com a solução de Lugol. Trata-se de um estudo prospectivo de teste de diagnóstico, para o qual foram avaliados 129 pacientes do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (HC-FMUSP), com diagnóstico de carcinoma epidermóide de cabeça e pescoço, em programa de rastreamento de tumores secundários, no período de agosto de 2006 a fevereiro de 2007. Os exames de endoscopia convencional, TBE e a cromoscopia com Lugol foram realizados consecutivamente em um mesmo procedimento, e as lesões encontradas foram registradas e submetidas a biópsias. Foram calculados para cada método valores da sensibilidade, especificidade, acurácia, valores preditivos positivos e negativos, valores de verossimilhança positivo e negativo. Foram diagnosticados nove carcinomas superficiais (7%), sendo cinco carcinomas in situ e quatro carcinomas intramucosos, todos detectados pelo TBE e pelo Lugol, porém apenas seis foram diagnosticados pelo exame convencional e destes, nenhum foi menor ou igual a 10 mm. A tecnologia de bandas estreitas com filtros ópticos (TBE) sem magnificação de imagem apresentou resultados superponíveis a cromoscopia com Lugol, método atualmente de escolha para rastreamento do CEC esofágico em grupos de pacientes de alto risco, portadores de tumores de cabeça e pescoço / Background and study aims: The aim of this study was to compare narrow band imaging (NBI) without magnification and chromoendoscopy with Lugols solution for detecting superficial esophageal squamous cell carcinoma in patients with head and neck cancer. Patients and methods: This is a prospective observational study of 129 patients with primary head and neck tumors consecutively referred to the Gastrointestinal Endoscopy Unit of Hospital das Clínicas, São Paulo University Medical School (FMUSP), Brazil, between August 2006 and February 2007. Conventional examinations, NBI and Lugol chromoendoscopy were consecutively performed, and the detected lesions were mapped, recorded and sent for biopsy. The results of the three methods were compared regarding sensitivity, specificity, accuracy, positive predictive value, negative predictive value, positive likelihood value and negative likelihood value. Results: Of the 129 patients, nine (7%) were diagnosed with carcinomas, five of which were in situ and four intramucosal. All carcinomas were detected through NBI and Lugol chromoendoscopy. Only six lesions were diagnosed by conventional examination, all of which were larger than 10 mm. Conclusions: Narrow-band imaging technology with optical filters has high sensitivity and high negative predictive value for detecting superficial esophageal squamous cell carcinomas and produces results comparable to those obtained with 2.0% Lugol chromoendoscopy in patients with head and neck cancer
554

Gastrostomia endoscópica em pacientes com neoplasia de cabeça e pescoço: comparação da técnica de introdução com gastropexia e técnica de tração / Endoscopic gastrostomy in patients with head and neck cancer: comparison of the pull and introducer with gastropexy techniques

Retes, Felipe Alves 24 May 2017 (has links)
Introdução: O câncer de cabeça e pescoço (CCP) ocupa mundialmente a sétima posição em incidência. Até dois terços dos pacientes com CCP podem apresentar disfagia já no diagnóstico da doença. A gastrostomia endoscópica percutânea (GEP) é, atualmente, o método de escolha para oferecer suporte nutricional por longo prazo. A técnica de tração é a mais utilizada por sua simplicidade e baixa morbidade. Entretanto, em pacientes com CCP, a presença de estenoses benignas ou malignas pode dificultar ou impedir a realização do procedimento, além de estar associada a maiores taxas de infecção local e implante tumoral para o sítio de punção da gastrostomia, quando comparada à técnica de introdução com gastropexia. Objetivo: Comparar as técnicas de GEP de tração e de introdução com gastropexia em pacientes com CCP. Métodos: Análise retrospectiva de banco de dados coletado prospectivamente, sobre pacientes com câncer de cabeça e pescoço submetidos à gastrostomia endoscópica percutânea. A técnica de tração foi realizada utilizando-se o kit de gastrostomia PEG 24® PULL METHOD (Cook Medical, Bloomington, Estados Unidos), enquanto a técnica de introdução com gastropexia foi realizada utilizando-se o kit de gastrostomia Freka® Pexact 15 (Fresenius-Kabi, BadHomburg, Alemanha). Resultados: 314 pacientes com câncer de cabeça e pescoço foram encaminhados para realização de GEP. O procedimento foi realizado com sucesso em 309 pacientes (98,4%), sendo 172 gastrostomias pela técnica de tração (GT) e 137 pela técnica de introdução (GI). Os dois grupos foram semelhantes em relação à idade, gênero, média dos níveis séricos de albumina e uso de anticoagulantes ou antiagregantes plaquetários. Os pacientes no GI, no entanto, apresentavam menor índice de Karnofsky (p=0,019) e maior presença de traqueostomia (p=0,003) e trismo (p < 0,001). A localização do tumor foi semelhante entre os dois grupos, no entanto, o estadiamento foi diferente. A maioria nos dois grupos apresentavam tumores estadio IV, entretanto alguns pacientes no grupo de tração apresentavam estadio I e II, enquanto no grupo de introdução não. A taxa total de complicações foi de 36,9%, sendo 5,8% maiores e 31,1% menores. As taxas de complicações imediatas e tardias foram de 6,5% e 30,4%, respectivamente. Não houve diferença estatisticamente significativa dessas taxas entre os dois grupos. Em relação às complicações isoladamente, as únicas que apresentaram diferença significativa foram sangramento menor no local da gastrostomia (p=0,006) e disfunção precoce da sonda (p=0,005), sendo ambas mais frequentes no grupo de introdução. Houve apenas um óbito relacionado ao procedimento, no GT. A mortalidade em 30 dias foi de 20,7%, semelhante entre os grupos. Conclusão: As duas técnicas de GEP apresentam altos índices de sucesso técnico em pacientes com CCP, porém com altos índices de complicações menores. A técnica de introdução com gastropexia apresenta risco aumentado de sangramento menor no local da gastrostomia e de disfunção precoce da sonda quando comparada à técnica de tração / Background: Head and neck cancer (HNC) is the seventh most frequent neoplasm in the world. Up to two-thirds of HNC patients present with dysphagia at diagnosis. Gastrostomy is the method of choice to provide long term tube feeding in patients who are unable to swallow. Percutaneous endoscopic gastrostomy (PEG) with the pull technique is the preferred procedure due to its simplicity and low complication rate. However, in HNC patients, severe stenosis or trismus may preclude the passage of the endoscope and there is an increased infection and PEG site metastasis rates, when compared to the introducer technique. Aim: Compare the pull and introducer with gastropexy PEG techniques in patients with HNC. Methods: Retrospective analysis of a prospectively collected database of HNC patients who underwent PEG. The pull technique was performed with the PEG 24® PULL METHOD (Cook Medical, Bloomington, United States) kit, while the introducer with gastropexy technique was done with the Freka® Pexact 15 (Fresenius-Kabi, BadHomburg, Germany) kit. Results: 314 patients with HNC were sent to the endoscopy unit for PEG. The procedure was successful in 309 (98,4%) patients. The pull technique was employed in 172 patients (PG) while the introducer technique with gastropexy was used in 137 patients (IG). Both groups were similar regarding age, gender, albumin level and the use of anticoagulant or antiplatelet drugs. However patients in the IG had a lower Karnofsky status (p=0,019) and presented more frequently tracheostomy (p=0,003) and trismus (p < 0,001). Although the tumor location was similar in both groups, the staging was different. Most patients presented with stage IV disease in both groups, however in the PG there were more patients with stage I or II. Overall complication rate was 36,9%, with 5,8% of major complications and 31,1% of minor complications. Immediate and late complication rates were 6,5% and 30,4%, respectively. These complications rates were similar in both groups. When the complications were analyzed individually, the IG presented higher minor bleeding (p=0,006) and tube dysfunction (p=0,005) rates. There was only one death directly related to the PEG, in the PG. The 30-day mortality was 20,7%, similar in both groups. Conclusion: The two PEG techniques present high technical success rate in patients with head and neck cancer, however with high minor complications rates. The introducer with gastropexy technique presents higher minor bleeding and tube dysfunction rates when compared to the pull technique
555

Análise morfoquantitativa e ultraestrutural dos componentes do plexo mioentérico do intestino delgado de ratos submetidos à dieta padrão de Moçambique nos períodos pré e pós-natal / Morphoquantitative and ultrastructural analysis on the myenteric plexus components of the rats small intestine with standard Mozambique diet in the pre and postnatal period

Marosti, Aline Rosa 16 June 2016 (has links)
Admite-se que mais de 40% das crianças são acometidas pela desnutrição crônica em Moçambique (África Oriental). A doença pode estar relacionada, entre outros fatores, à qualidade da dieta que é oferecida à população, já que é bastante precária, pois exibe sérias deficiências de ferro, gordura e, principalmente, proteína animal em sua composição. Essa insuficiência proteica poderia acarretar em prejuízo ao desenvolvimento do organismo, pois a proteína animal é considerada uma boa fonte de aminoácidos essenciais, em decorrência de sua maior digestibilidade e absorção no intestino delgado, quando comparadas às fontes de origem vegetal. Na presente pesquisa foi reproduzida em laboratório, a dieta básica da população de Moçambique (DM), com o objetivo de avaliar seus efeitos nos componentes do plexo mioentérico e na mucosa dos segmentos do intestino delgado de ratos Wistar. Para isso, os animais foram divididos nos grupos Controle, com dieta AIN-93G com adição de 20% de caseína (NN21 e NN42); Dieta de Moçambique (DM21 e DM42) e Dieta Moçambique suplementada, acrescida de 20% de caseína (NM21 e NM42); e grupo Renutrido (RM42), composto por animais do grupo DM21 que, a partir do 22º dia, receberam a dieta NM até atingirem 42 dias de vida. Os segmentos foram coletados e submetidos às técnicas histoquímicas da NADH-diaforase e da NADPH-diaforase para evidenciação de neurônios do plexo mioentérico; histológicas (HE, Picro-sírius, Weigert) para avaliação da parede intestinal, mucosa, gânglios e seu tecido conjuntivo associado; de microscopia eletrônica de varredura (MEV) para observação da estrutura da mucosa; e de microscopia eletrônica de transmissão (MET) para a ultraestrutura dos componentes ganglionares. Estatisticamente, o peso corporal e o comprimento dos animais submetidos à dieta de Moçambique estavam abaixo dos valores encontrados para os animais controle. Na análise qualitativa, observou-se a presença de fibras elásticas, elaunínicas e oxitalânicas, assim como predominância de fibras colágenas do tipo I nos grupos NN42 e DM42, e do tipo III nos grupos NM42 e RM42 ao redor dos gânglios. A mucosa apresentou uma menor área no grupo DM21 com recuperação em DM42, com diminuição da altura das vilosidades nos dois grupos. Foram observadas alterações na organização do retículo endoplasmático rugoso e disposição dos materiais fibrilares e granulares do nucléolo dos animais DM. Sob MEV as vilosidades do grupo DM42 apresentaram superfície mais lisa, com poucas delimitações entre elas. A densidade dos neurônios reativos à NADH diminuiu de 21 para 42 dias em todos os grupos; porém, o DM21 e DM42 apresentou uma maior densidade. Os neurônios reativos à NADPH apresentaram a diminuição da densidade de 21 para 42 dias nos grupos DM e NM, quando comparados ao controle. Assim, conclui-se que a dieta vegetal de Moçambique levou à alterações na morfologia da mucosa, parede intestinal e neurônios entéricos, como uma forma de adaptação à dieta imposta / It is assumed that more than 40% of children are affected by chronic malnutrition in Mozambique (East Africa). The disease may be related, among other factors, the quality of diet that is offered to the population, since it is quite precarious, because it displays serious deficiencies of iron, fat and especially animal protein in their composition. This protein failure could result in damage to the development of the organism, as animal protein is considered a good source of essential amino acids, due to its higher digestibility and absorption in the small intestine when compared to vegetable sources. In this research has been reproduced in the laboratory, the staple diet of the population of Mozambique (DM), in order to evaluate its effects on components of the myenteric plexus and the mucosa of the small intestine segments of Wistar rats. For this, the animals were divided into control groups with AIN-93G diet with the addition of 20% casein (NN21 and NN42); Diet Mozambique (DM21 and DM42) and diet supplemented Mozambique, plus 20% casein (NM21 and NM42); and Refeeding group (RM42), consisting of the animals DM21 group, from the 22th day, given NM diet until they reached 42 days of life. The segments were collected and submitted to histochemical techniques of NADH-diaphorase and NADPH-diaphorase for disclosure of neurons of the myenteric plexus; histologic (HE, Sirius red, Weigert) for evaluation of the intestinal wall, mucosa, lymph nodes and its associated connective tissue; scanning electron microscopy (SEM) for observation of mucosal structure; and Transmission electron microscopy (TEM) ultrastructure to ganglion components. Statistically, body weight and length of the animals submitted to Mozambique diet were below the values found for control animals. Qualitative analysis showed the presence of elastic fibers, and elauninic oxytalan, and predominance of type I collagen fibers in the NN42 and DM42 groups, and type III in the NM42 and RM42 groups around the ganglia. The mucosa showed a smaller area in DM21 group recovery DM42, with a decrease in villus height in both groups. There have been changes in the organization of the rough endoplasmic reticulum and arrangement of fibrillar and granular materials nucleolus of DM animals. Under SEM the villi of the DM42 group showed smoother surface, with few boundaries between them. The density of reactive NADH decreased from 21 to 42 days in all groups; however, the DM21 and DM42 had a higher density. Reactive neurons to NADPH had decreased from 21 to 42 days density in DM and NM groups when compared to the control. Thus, it is concluded that vegetable diet Mozambique led to changes in the morphology of the mucosa, the intestinal wall and enteric neurons, as a way to adapt to the imposed diet
556

Synopsis of video streams and its application to computer aided diagnosis for GI tract abnormalities based on wireless capsule endoscopy (CE) video. / CUHK electronic theses & dissertations collection

January 2012 (has links)
無線膠囊內窺鏡(CE)是一種用於檢查整個胃腸道,尤其是小腸的無創技術。它極大地改善了許多小腸疾病的診斷和管理方式,如不明原因的消化道出血,克羅恩病,小腸腫瘤,息肉綜合征等。儘管膠囊內窺鏡有很好的臨床表現,但它仍然有一定的局限性。主要問題是每次檢查產生約50,000 幅低質量的圖像,對於醫生來說,評估如此大量的圖像是一項非常耗時、耗力的工作。 / 到目前為止,對於膠囊內窺鏡的分析和評估,學者們都把膠囊內窺鏡圖像視為單獨的,獨立的觀測對象。事實並非如此,因為圖像之間往往有顯著的重疊。特別是當膠囊內窺鏡在被小腸蠕動緩緩推動時,它可以捕捉同一病灶的多個視圖。我們的研究目的是使用所有可用的資訊,包括多幅圖像,研究對於膠囊內窺鏡的電腦輔助診斷(CAD)系統。 / 在這篇論文中,我們提出了一個嵌入分類器的多類隱馬爾可夫模型(HMM)的方案,它可以融合多幅相鄰圖像的時間資訊。由於膠囊內窺鏡圖像的品質比較低,我們首先進行預處理,以加強膠囊內窺鏡圖像,增加其對比度,消除噪聲。我們調查研究了多種圖像增強的方法,並調整了它們的參數使其適用於膠囊內窺鏡圖像。 / 對於基於單幅圖像的有監督的分類,AdaBoost 作為一個集成分類器來融合多個分類器,即本論文中的支持向量機(SVM),k-近鄰(k-NN),貝葉斯分類。在分類之前,我們提取和融合了顏色,邊緣和紋理特徵。 / 對於無線膠囊內窺鏡的視頻摘要,我們提出了有監督和無監督的兩類方法。對於有監督方法,我們提出了一個基於隱馬爾可夫模型的,靈活的,可擴展的框架,用於整合膠囊內窺鏡中連續圖像的時間資訊。它可以擴展到多類別,多特徵,多狀態。我們還提出了聯合隱馬爾可夫模型和並行隱馬爾可夫(PHMM)模型對系統進行改進,它們可以被看作是決策級的資訊融合。聯合隱馬爾可夫模型通過多層次的隱馬爾可夫模型,結合不同的資訊來源,對膠囊內窺鏡視頻進行分類和視頻摘要。 並行隱馬爾可夫模型採用貝葉斯推理,在決策時融合多個不同來源的資訊。對於無監督的方法,我們首先提出了一種基於顏色的特徵提取方法。在反色顏色空間中對亮度不變的色度不變矩用來表示膠囊內窺鏡圖像的顏色特徵。接著,我們又提出了一種基於輪廓元(Contourlet)變換的局部二元模式(LBP)作為紋理特徵。在特徵空間中,我們測量了相鄰圖像的距離,並把它視為一個位於二維平面上的開放輪廓上的點。 然後,我們採用一個無參數的關鍵點檢測方法檢測在視頻片段上的突變關鍵點。基於這些突變關鍵點,我們對膠囊內窺鏡視頻進行分割。最後,在每段被分割的視頻片段上,我們通過提取有代表性的關鍵幀來實現膠囊內窺鏡視頻摘要。我們分別用模擬和真實的病人數據進行實驗,對提出的方法進行驗證,結果表明了我們所提出的方案的有效性。它在實現自動評估膠囊內窺鏡圖像上具有很大的潛力。 / Wireless Capsule Endoscopy (CE) is a non-invasive technology to inspect the whole gastrointestinal (GI) tract, especially the small intestine. It has dramatically changed the way of diagnosis and management of many diseases of the small intestine, such as obscure gastrointestinal bleeding, Crohn’s disease, small bowel tumors, polyposis syndromes, etc. Despite its promising clinical findings, it still has some limitations. The main problem is that it requires manual assessment of approximately 50,000 low quality images per examination which is highly time-consuming and labor-intense. / CE analysis and assessment so far treated CE images as individual and independent observations. It is obviously not the case as there is often significant overlap among images. In particular, CE captures multiple views of the same anatomy as the capsule is slowly propelled by peristalsis. Our broader work aims to perform computer aided diagnosis (CAD) in endoscopy using all available information, including multiple images. / In this dissertation, a framework of multi-class Hidden Markov Models (HMM) embedded with statistical classifiers for combining information from multiple CE images is proposed. Due to the low quality of CE image, pre-processing is performed to enhance CE images by increasing the contrast and removing noises. Several image enhancement methods are investigated and customized for CE images. For frame-based supervised classification, AdaBoost is used as the ensemble classifier to combine multiple classifiers, i.e. support vector machine (SVM), k-nearest neighbor (k-NN), and Bayes classifier. Before classification, color, edge and texture features are extracted and fused. Finally, both supervised and unsupervised methods are proposed for CE study synopsis. For supervised method, a flexible and extensible framework based on HMM is developed to integrate temporal information in CE images. It can be extended to multi-class, multi-features, and multi-states. Improvements can be made by combined HMM and Parallel HMM (PHMM) which are introduced as decision-level fusion schemes. Combined HMM considers different sources via a multi-layer HMM model to perform classification and video synopsis. PHMM employs Bayesian inference to combine the recognition results at decision level. For unsupervised method, illumination-independent opponent color moment invariants and local binary pattern (LBP) based on Contourlet transform are explored as color and texture features, respectively. Pair-wise image dissimilarity is measured in the feature space and treated as points on an open contour in a 2-D plane. CE video is segmented based on sudden change points which are detected using a non-parametric key-point detection method. From each segment, representative frames are extracted to summarize the CE video. Validation results on simulated and real patient data show promising performance of the proposed framework. It has great potential to achieve automatic assessment for CE images. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Zhao, Qian. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 142-175). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract --- p.ii / Acknowledgments --- p.vii / List of Tables --- p.xiii / List of Figures --- p.xv / Chapter 1 --- The Relevance of Synopsis --- p.1 / Chapter 1.1 --- Problem Statement --- p.1 / Chapter 1.2 --- Application - Capsule Endoscopy Assessment --- p.4 / Chapter 1.3 --- Literature Review --- p.9 / Chapter 1.3.1 --- Methods Based on Frame Classification --- p.11 / Chapter 1.3.2 --- Methods Integrating Temporal Information --- p.14 / Chapter 1.4 --- Contributions --- p.19 / Chapter 1.5 --- Organization --- p.23 / Chapter 2 --- Preliminary --- p.25 / Chapter 2.1 --- Hidden Markov Model (HMM) --- p.25 / Chapter 2.2 --- Factorial HMM --- p.35 / Chapter 3 --- Temporal Integration in Capsule Endoscopy Image Analysis --- p.37 / Chapter 3.1 --- Pre-processing --- p.38 / Chapter 3.2 --- Feature Extraction --- p.43 / Chapter 3.3 --- Frame-based Supervised Classification --- p.47 / Chapter 3.3.1 --- Supervised Classification using Individual Frames --- p.47 / Chapter 3.3.2 --- Ensemble Learning Based on AdaBoost --- p.50 / Chapter 3.4 --- Sequence-based Supervised Classification --- p.52 / Chapter 3.5 --- Experiments --- p.58 / Chapter 3.5.1 --- Capsule Endoscopy Image Enhancement --- p.60 / Chapter 3.5.2 --- Frame-based Supervised Classification --- p.67 / Chapter 3.5.3 --- Image Sequence Classification --- p.68 / Chapter 3.6 --- Discussion --- p.80 / Chapter 3.7 --- Summary --- p.82 / Chapter 4 --- Capsule Endoscopy Study Synopsis --- p.98 / Chapter 4.1 --- Supervised Synopsis Using Statistical Models --- p.98 / Chapter 4.2 --- Unsupervised Synopsis via Representative Frame Extraction --- p.100 / Chapter 4.2.1 --- Feature Extraction --- p.100 / Chapter 4.2.2 --- Non-parametric Key-point Detection --- p.111 / Chapter 4.2.3 --- Representative Frame Extraction --- p.112 / Chapter 4.3 --- Experiments --- p.119 / Chapter 4.3.1 --- Supervised Synopsis Based on HMM --- p.119 / Chapter 4.3.2 --- Unsupervised Synopsis --- p.125 / Chapter 4.4 --- Discussion --- p.132 / Chapter 4.5 --- Summary --- p.133 / Chapter 5 --- Conclusions and Future Work --- p.138 / Chapter 5.1 --- Conclusions --- p.138 / Chapter 5.2 --- Future Work --- p.141 / Bibliography --- p.142
557

A study on computer-aided diagnosis for wireless capsule endoscopy images. / CUHK electronic theses & dissertations collection

January 2008 (has links)
A feature extraction approach based on color is firstly proposed. Exploiting color histogram of an image, we can obtain distribution of different colors in images. Then we employ minimum distance classifier based on a new distance criterion to judge status of regions. In this section, we also validate benefits of WCE image enhancement to the proposed CAD system. / Finally, we propose a new approach of chrominance moment as another kind of feature to discriminate normal regions from abnormal regions, which makes full use of Tchebichef polynomials and HSI color space. This new feature extraction scheme preserves illumination invariance without numerical approximation. / In conclusion, this thesis investigates several major and challenging problems such as WCE images enhancement and feature extractions in CAD for WCE images, and proposes several novel schemes to solve those problems. Extensive experiments are reported to demonstrate effectiveness of the proposed algorithms. / Next, we investigate automatic diseases detection for WCE images to partially solve the second problem. In this part we explore different features that are suitable for detection of diseases from three viewpoints, i.e., color, texture and chromaticity, because clinicians mainly use these clues to diagnose. At the same time, we introduce their corresponding classifiers. / We further advance a new texture feature extraction method, curvelet based local binary pattern, to detect abnormal regions in WCE images. This method takes advantage of curvelet transform and local binary pattern to describe textural features of WCE images. / Wireless capsule endoscopy (WCE) is a state-of-the-art technology to diagnose gastrointestinal (GI) tract diseases without invasiveness. However, there exist two major problems concerning WCE images. One problem is that many images for diagnosis have rather low contrast and are noisy, which causes difficulties to diagnosis and also to computer-aided detection, so it is necessary to enhance these images. The other one is that the viewing process of video data per examination is very time consuming because of the great amount of video data. If we can use computerized methods to help the physicians detect some abnormal regions in WCE images, it will certainly reduce the burden of physicians. Focusing on these two goals, this thesis mainly studies some main challenging problems in computer-aided diagnosis (CAD) system for WCE images. To solve the first problem, we put forward an adaptive curvature strength diffusion method to enhance WCE images. Based on local characteristics analysis of WCE images, we propose a new concept of curvature strength. Then, we employ curvature strength diffusion to enhance WCE images with an adaptive choice of conductance parameter. Finally, we extend the curvature strength diffusion to color space since WCE images are color images. / Li, Baopu. / Adviser: Max Q. H. Meng. / Source: Dissertation Abstracts International, Volume: 70-06, Section: B, page: 3640. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 126-150). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts in English and Chinese. / School code: 1307.
558

"Comparação da reação em cadeia da polimerase com o exame microscópico na detecção do Trypanosoma cruzi em amostras procedentes do trato digestório do Triatoma infestans" / Comparison of Polymerase Chain Reaction with Microscopic Examination to detect Trypanosoma cruzi in Triatoma infestans digestive tract samples

Lucia Maria Almeida Braz 27 June 2006 (has links)
O presente estudo comparou a PCR com o exame microscópico (EM) na detecção do T. cruzi em amostras do trato digestório do T. infestans, do 1º ao 5º, 10º, 15º, 20º, 25º, 30º e 60º dia, após repasto sanguíneo em camundongos Balb/C infectados pelo T. cruzi, divididos em grupos de alta e baixa parasitemia. Concluiu-se que a PCR apresentou vantagens em termos diagnósticos para a doença de Chagas quando comparada ao EM, em 10 dos 11 tempos estudados no grupo de alta parasitemia, e em todos os tempos na baixa parasitemia. O diagnóstico precoce na baixa parasitemia é de relevância clínica já que poderá influenciar o prognóstico dos pacientes imunossuprimidos com reativação da doença de Chagas / Detection of T. cruzi in T. infestans digestive tract samples was compared by PCR and microscopic examination (ME) on the 1st to 5th, 10th, 15th, 20th, 25th, 30th and 60th day after feeding in Balb/C mice infected by T. cruzi, and divided in two groups: with high parasitemia and with low parasitemia. PCR presented vantages to the Chagas' disease diagnosis when compared with EM in 10 of 11 times in high parasitemia, and in all times in low parasitemia. Earlier diagnosis in low parasitemia model is of clinical relevance since may influence prognosis of immunosupressed patients in reactivation of Chagas' disease
559

Respostas transcriptômica e sistêmica de hormônios gastrintestinais à  derivação gástrica em Y de Roux e sua correlação com homeostase glicêmica em pacientes obesas portadoras de diabetes mellitus tipo 2 / Transcriptomic and systemic responses of gastrointestinal hormones to Roux-en-Y gastric bypass and its correlation with glycemic homeostasis in obese patients with type 2 diabetes mellitus

Candian, Danielle Cristina Fonseca 03 April 2018 (has links)
Indivíduos obesos, portadores de diabetes mellitus tipo 2 (DM2), atingem controle glicêmico poucos dias após realização de derivação gástrica em Y de Roux (DGYR), antes mesmo de ocorrer perda de peso significativa. Entre os mecanismos propostos, para explicar o rápido controle glicêmico, a alteração da produção de hormônios gastrintestinais é muito estudada, porém pouco se explorou a expressão tecidual dos genes que os transcrevem. O presente estudo avaliou a resposta, em curto prazo, da expressão gástrica e intestinal de genes que transcrevem peptídeo semelhante ao glucagon 1 (GLP-1), peptídeo insulinotrópico dependente de glicose (GIP), peptídeo tirosina-tirosina (PYY) e grelina, e de níveis sistêmicos desses hormônios à DGYR, bem como, sua correlação com homeostase glicêmica pós-operatória. Mulheres obesas portadoras de DM2 (n=20) foram avaliadas antes e após 3 meses de DGYR. Todas as pacientes foram avaliadas em conjunto e, posteriormente, divididas em dois subgrupos de doentes, determinados pelo grau de remissão pós-operatória de DM2 (parcial ou completa) de acordo com o critério ADA. Biopsias do corpo e fundo gástrico, duodeno, jejuno e íleo foram coletadas por enteroscopia de duplo balão para análise de expressão dos genes GCG (precursor do GLP-1), GIP (precursor do GIP), PYY (precursor de PYY) e GHRL (precursor da grelina). As análises de expressão gênica foram feitas por abordagem global e alvo, por meio das técnicas de microarray e RT-qPCR, respectivamente. Concentrações plasmáticas dos hormônios transcritos pelos genes avaliados também foram dosadas em jejum e após teste de refeição mista, bem como níveis circulantes de peptídeo C, hemoglobina glicada (jejum), glicose, insulina e glucagon (jejum e após teste de refeição mista). Essa abordagem permitiu avaliar a correlação de dados teciduais de expressão gênica e de níveis circulantes de hormônios GI com marcadores sistêmicos de homeostase glicêmica. Após DGYR, alterações significativas na expressão de GCG, GIP, PYY e GHRL ocorreram ao longo dos segmentos GI estudados, em paralelo à melhora significativa de marcadores plasmáticos da homeostase glicêmica. Particularmente, aumento da expressão de GCG e diminuição da expressão de GIP ao longo do intestino foram acompanhados por alterações sistêmicas concordantes dos hormônios por eles transcritos. Essas alterações transcriptômicas se correlacionaram direta (GCG) e inversamente (GIP) com níveis de insulina e glicose, e, inversamente, com níveis de hemoglobina glicada (GCG e GIP). Apenas o hormônio GLP-1 se correlacionou inversamente com níveis de hemoglobina glicada. Além disso, as pacientes com remissão completa de DM2 apresentaram, em relação às medidas pré-operatórias, aumento de GCG no jejuno e íleo, e aumento significativo da área sob a curva de GLP-1 ativo após DGYR. No estômago excluso, ocorreu aumento da expressão de GHRL, mas os níveis sistêmicos de grelina não sofreram alterações significativas no pós-operatório. De acordo com nossos dados, DGYR modificou a expressão de genes que transcrevem hormônios GI capazes de influenciar a homeostase glicêmica. Essas alterações foram acompanhadas por modificações concordantes de níveis sistêmicos das incretinas GLP-1 e GIP e se correlacionaram com marcadores de melhora da homeostase glicêmica. Em conjunto, nossos resultados sugerem que DGYR pode influenciar a homeostase glicêmica por mecanismos que incluem modificação transcriptômica de genes relacionados a hormônios gastrintestinais / Obese subjects with type 2 diabetes mellitus (T2DM) achieve glycemic control few days after Roux-en-Y gastric bypass (RYGB), even before significant weight loss occurs. Among all proposed mechanisms to explain the rapid glycemic control after surgery, alteration of gastrointestinal (GI) hormones production is widely studied, however, GI expression of these genes is still little explored. The present study evaluated the short-term response of gastric and intestinal expression of genes transcribing glucagon-like peptide 1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), tyrosine-tyrosine peptide (PYY), and ghrelin and systemic levels of these hormones after RYGB, as well as their correlation with postoperative glycemic homeostasis. Obese women with T2DM (n = 20) were assessed before and after 3 months of RYGB. All patients were evaluated together and subsequently divided in two subgroups of patients, according the degree of postoperative T2DM remission (partial or complete), following ADA criteria. Biopsies of body and gastric fundus, duodenum, jejunum and ileum were collected by double-balloon enteroscopy for analysis of GCG (precursor of GLP-1), GIP (GIP precursor), PYY (precursor of PYY) and GHRL ghrelin precursor). Gene expression analysis was done by global and target approach, using microarray and RT-qPCR techniques, respectively. Plasmatic concentrations of hormones transcribed by the genes under study were also measured in fasted and after mixed meal test samples, as well as circulating levels of C peptide, glycated hemoglobin (fasting), glucose, insulin and glucagon (fasting and after mixed meal test). This approach allowed the correlation of tissue expression data and circulating levels of GI hormones with systemic markers of glycemic homeostasis. After RYGB, significant changes in GCG, GIP, PYY and GHRL expression were observed along the studied GI segments, in parallel with significant improvement in plasma markers of glycemic homeostasis. In particular, increased GCG expression and decreased GIP expression throughout the small intestine was followed by consistent systemic alterations of its related hormones. These transcriptomic changes are directly (GCG) and inversely (GIP) correlated with insulin and glucose levels and inversely with glycated hemoglobin levels (GCG and GIP). Only GLP-1 was inversely correlated with glycated hemoglobin levels. In addition, regarding the preoperative measurements, patients with complete T2DM remission presented increased GCG in jejunum and ileum, and significant increase in the area under curve of active GLP-1 after RYGB. In the excluded stomach, an increase in GHRL gene expression was recognized, but systemic levels of ghrelin did not changed significantly. According to our data, RYGB altered the expression of genes that transcribe GI hormones related to glycemic homeostasis. These changes were followed by expected modifications of GLP-1 and GIP incretin systemic levels and were correlated with improved glycemic homeostasis markers. Taken together, our results suggest that RYGB can influence glycemic homeostasis by mechanisms that include transcriptomic modification of genes related to gastrointestinal hormones
560

Aspects on prognosis of cancers of the oesophagus and gastric cardia /

Sundelöf, Martin, January 2006 (has links)
Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

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