• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 214
  • 202
  • 35
  • 8
  • 7
  • 7
  • 6
  • 6
  • 5
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • Tagged with
  • 575
  • 161
  • 85
  • 65
  • 60
  • 55
  • 55
  • 49
  • 48
  • 44
  • 42
  • 37
  • 37
  • 35
  • 34
  • 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.
301

Avaliação da recidiva do carcinoma hepatocelular em pacientes submetidos a transplante de fígado no Brasil / Recurrence of hepatocellular carcinoma assessment in patients submitted to liver transplantation in Brazil

Aline Lopes Chagas 01 December 2017 (has links)
INTRODUÇÃO: O transplante (TX) de fígado corresponde ao tratamento de escolha em pacientes com cirrose e carcinoma hepatocelular (CHC) precoce irressecável. A recidiva do CHC pós-transplante, entretanto, ainda apresenta impacto na sobrevida dos pacientes transplantados com este tumor. As taxas de recidiva, nos estudos mais recentes, variam de 8 a 20%. O tamanho e número de nódulos, a presença de invasão vascular e de nódulos satélites no explante, são fatores de risco relacionados à recidiva tumoral pós-transplante. No Brasil, observamos um crescimento importante do número de transplantes de fígado, inclusive por CHC. Entretanto, existem poucos estudos nacionais analisando os resultados do transplante hepático por CHC. Os objetivos do nosso estudo foram analisar as características demográficas, clínicas e a evolução dos pacientes submetidos a transplante hepático com CHC no Brasil, avaliando os fatores prognósticos relacionados com a recidiva do CHC pós-transplante e sobrevida e estudar o desempenho dos critérios de seleção para transplante utilizados no nosso país, os \"Critérios de Milão Brasil\" (CMB). MÉTODOS: Estudo de coorte retrospectivo, multicêntrico, para analisar os resultados do transplante de fígado em pacientes com CHC, após a implantação do sistema MELD. Foram incluídos 1.119 pacientes transplantados com CHC, de 07/2006 até 07/2015, em 13 centros de transplante, no Brasil. Características clínicas, demográficas, exames laboratoriais e de imagem e dados anatomopatológicos, foram retrospectivamente analisados e correlacionados com a sobrevida e recidiva do CHC pós-transplante. RESULTADOS: A maioria dos pacientes era do sexo masculino (81%), com uma idade média no TX de 58 anos. A etiologia mais associada ao tumor foi a Hepatite C (VHC), presente em 60% dos casos. O tempo médio de espera em lista foi de 9,8 meses. Setenta e oito pacientes (8%) foram incluídos por \"Down-staging\". Nos exames de imagem do diagnóstico, a maioria dos casos (67%) apresentava um nódulo, com tamanho médio de 30 mm; 85% estavam dentro dos Critérios de Milão (CM), 8% fora dos CM, mas dentro dos \"Critérios de Milão Brasil\" (CMB) e 7% fora de ambos os critérios. O tratamento do CHC em lista foi realizado em 67% dos pacientes. Na análise do explante, 44% apresentavam tumor uninodular, com tamanho médio de 26 mm e a maioria (71%) tinha CHC moderadamente diferenciado. A invasão vascular foi observada em 26% dos casos e nódulos satélites em 22%. No explante, 70% dos pacientes estavam dentro dos CM, 20,5% fora dos CM, mas dentro dos CMB e 9,5%fora de ambos os critérios. A sobrevida global foi de 79% em 1 ano, 72,5% em 3 anos e 63%, em 5 anos, com um tempo médio de seguimento de 28 meses. Excluindo os pacientes que foram a óbito no pós-operatório ( < 30 dias pós-transplante), a sobrevida global foi de 89% em 1 ano e 75%, em 5 anos. A recidiva do CHC pós-TX ocorreu em 8% (86/1.119) dos casos, em um tempo médio de 12 meses. A sobrevida livre de recidiva (SLR) foi de 94,4% em 1 ano e 88,3%, em 5 anos. A recidiva do CHC foi extra-hepática em 55% dos casos, hepática em 27% e hepática e extra-hepática em 18%. Os pacientes transplantados que evoluíram com recidiva tumoral apresentaram alta mortalidade, com uma sobrevida em 1 ano de 34% e em 5 anos de 13%. Em relação aos fatores prognósticos, os pacientes transplantados dentro dos Critérios de Milão apresentaram melhor sobrevida e SLR quando comparados aos pacientes transplantados fora dos CM, mas dentro dos CMB, tanto quando analisamos os dados do diagnóstico, quanto através da análise do explante. Os pacientes transplantados após realização de \"Down-staging\" apresentaram taxas de recidiva e sobrevida semelhantes aos pacientes transplantados sem \"Down-staging\". Os níveis séricos elevados de alfa-fetoproteína (AFP) foram um fator prognóstico importante de sobrevida e recidiva tumoral. Os melhores pontos de corte de AFP encontrados para avaliação do risco de recidiva e sobrevida foram: AFP > 400 ng/ml, no momento do diagnóstico e AFP > 200 ng/ml pré-transplante. Realizamos, também, uma comparação dos \"Critérios de Milão Brasil\" com os Critérios de Milão, através do índice IDI (Integrated Discrimination Index) e os CMB apresentaram performance inferior aos CM, na capacidade de classificar corretamente os pacientes em relação ao risco de recidiva tumoral. Os níveis séricos elevados de AFP, o estádio fora dos Critérios de Milão no momento do diagnóstico e no explante e a presença e invasão vascular no explante, foram fatores de risco independentes de recidiva do CHC pós-transplante e pior sobrevida. A idade > 60 anos e a etiologia da hepatopatia (VHC), também foram fatores prognósticos negativos de sobrevida. CONCLUSÕES: A presença de recidiva tumoral teve grande impacto na sobrevida do paciente transplantado com CHC. O estadiamento tumoral no diagnóstico e no explante, avaliado através dos Critérios de Milão, os níveis séricos elevados de AFP e a presença de invasão vascular no explante foram fatores prognósticos importantes de recidiva do CHC pós-transplante e sobrevida. Os pacientes transplantados após \"Down-staging\" apresentaram evolução pós-transplante semelhante a dos pacientes transplantados sem \"Down-staging\". Os pacientes transplantados fora dos CM, mas dentro dos CMB, apresentaram pior sobrevida, quando comparados aos pacientes dentro dos CM. Os CMB apresentaram desempenho inferior aos CM na capacidade de classificar corretamente os pacientes em relação ao risco de recidiva tumoral / INTRODUCTION: Liver transplantation (LT) is the treatment of choice for patients with cirrhosis and unresectable early hepatocellular carcinoma (HCC). HCC post-transplant recurrence, however, still has an impact on survival. In recent studies, the incidence of HCC recurrence after transplantation ranged from 8% to 20%. Tumor number, size, vascular invasion and satellite nodules have emerged as risk factors for HCC recurrence. In Brazil, in the last decade, we observed a significant increase in the number of liver transplants performed, including in patients with HCC. However, there are few national studies analyzing the results of liver transplantation for HCC. The aim of this multicentric study was to analyze the demographic characteristics, clinical features and outcomes of patients submitted to liver transplantation with HCC in Brazil, evaluate prognostic factors related to HCC post-transplant recurrence and survival, and study the performance of the national selection criteria for liver transplantation, the \"Brazilian Milan Criteria\" (BMC). METHODS: We conducted a national, multicentric, retrospective study to analyze the results of liver transplantation in patients with HCC, in \"MELD era\". Medical records of 1,119 transplanted patients with HCC between 07/2006 and 07/2015, from 13 transplant centers in Brazil, were collected. Patient and tumor characteristics, radiologic and pathologic data were retrospectively analyzed and correlated with post-transplant HCC recurrence and survival. RESULTS: Of the 1,119 HCC transplanted patients, median age was 57 years and 81% were male. Etiology of liver disease was HCV in 60%. Median time on transplant list was 9.8 months. Seventy-eight patients (8%) were included after \"Down-staging\". At diagnosis, most patients had uninodular HCC (67%) and median tumor burden was 30 mm. At diagnosis, in imaging studies, 85% of patients were within the Milan criteria (MC), 8% out of the MC but within the \"Brazilian Milan Criteria\" (BMC) and 6% out of both criteria. During the waiting list period, HCC treatment was performed in 67%. In explant analysis, tumor was uninodular in 46% and moderately differentiated in the majority of cases (71%). Median HCC size was 26 mm. Vascular invasion and satellite nodules were observed in 26% and 22% of patients, respectively. In explant, 70% of patients were within Milan Criteria, 20.5% outside MC but within BMC and 9.5% out of both criteria. Mean follow-up was 28 months, an overall survival was 79% in 1 year, 72.5% in 3 years and 63% in 5 years. Excluding patients who died within 30 days after surgery, overall survival was 89% in 1 year and 75% in 5 years. HCC post-transplant recurrence occurred in 86/1,119 (8%) cases, at a mean time of 12 months. Recurrence-free survival (RFS) was 94.4% in 1 year and 88.3% in 5 years. Sites of recurrence were extrahepatic in 55%, hepatic in 27% and both hepatic and extrahepatic in 18%. Transplanted patients with tumor recurrence presented high mortality, with 1-year survival rate of 34% and 5-year survival rate of 13%. Analyzing the prognostic factors, patients transplanted under Milan Criteria, in radiologic or explant analysis, presented better survival and RFS when compared to patients transplanted outside MC, but within BMC. Patients submitted to liver transplantation after \"Down-staging\" present long-term survival and RFS similar to patients transplanted without \"Down-staging\". Alpha-fetoprotein (AFP) levels were an important pre-transplant prognostic factor for tumor survival and recurrence. The best AFP cut off points found for relapse risk and survival assessment were: AFP at diagnosis > 400 ng / ml and AFP pre-transplant > 200 ng / ml. We also performed a comparison of the \"Brazilian Milan Criteria\" with the Milan Criteria through the Integrated Discrimination Index (IDI). The BMC presented a lower performance than the MC, in the ability to correctly classify patients in relation to the risk of relapse. Elevated AFP levels before liver transplantation, tumor outside Milan Criteria at diagnosis and in explant, and vascular invasion, were independent risk factors for post-transplant HCC recurrence and worse survival. Age > 60 years and etiology of liver disease (HCV), were also negative prognostic factors for survival. CONCLUSIONS: The presence of tumor recurrence had a major impact on survival of transplanted patients with HCC. Tumor staging, evaluated by Milan Criteria on imaging studies or explant analysis, high serum AFP levels and presence of vascular invasion in explant were important prognostic factors for post-transplant HCC recurrence and survival. Patients transplanted after Down-staging presented long-term outcomes similar to patients transplanted under conventional criteria. Patients transplanted outside Milan Criteria, but within \"Brazilian Milan Criteria\" presented worse survival, when compared to patients within MC. The BMC showed lower performance than MC in the ability to correctly classify patients in relation to the risk of tumor recurrence
302

"Fatores clínicos e biológicos para recidivas em tumores de Wilms localizados" / Clinical and biological factors for relapse in localized wilms' tumor

Roberto Augusto Plaza Teixeira 05 September 2005 (has links)
Apesar do excelente prognóstico dos tumores de Wilms (TW) localizados (estádios I e II) e de histologia favorável (HF), 10% deles recidivam. Em 122 pacientes com TW com essas características, diagnosticados de 1976 e 2001, analisamos alguns fatores clínicos, como a idade por ocasião do diagnóstico e peso do tumor, em todos os pacientes; fatores biológicos, como o TP53 e a glicoproteína-p, em 40 deles; e variáveis histológicas de microestadiamento (invasão de seio renal, cápsula tumoral, vasos intra-renais e pseudocápsula inflamatória) em 28 com TW em estádio I. Correlacionando todos esses fatores com a presença de recidiva, observamos que a chance maior de recidiva estatisticamente significativa somente foi verificada em pacientes com duas ou mais variáveis de microestadiamento e/ou peso tumoral maior que 550 g / In spite of the excellent prognosis of localized favorable histology (FH) of Wilms' tumor (WT), 10% of them will relapse. In 122 TW patients with these characteristics, diagnosed between 1976 and 2001, some clinical factors have been analyzed, such as age at diagnosis and tumor weight in all patients; biological factors, like TP53 and p-glycoprotein, in 40 of them; and microsubstaging histological variables (invasion of renal sinus, tumor capsule, intrarenal vessels, and inflammatory pseudocapsule). Correlating all of those factors with relapse, we have observed that only patients with the association of two or more microsubstaging variables and/or tumor weight over 550 g showed a statistically significant higher chance of relapse
303

Qualidade de vida e transplante hepático: avaliação comparativa em diferentes fases pré e pós cirurgia / Quality of life and liver transplantation: evaluation in different stages before and after surgery

Daniela Rosa Magalhães Gotardo 18 May 2007 (has links)
O transplante de fígado é definido como a terapêutica de escolha para as doenças hepáticas em estágio terminal. Por muitos anos, o sucesso deste procedimento foi mensurado pelas taxas de mortalidade e a freqüência de complicações nas anastomoses biliares e complicações infecciosas. No entanto, mais recentemente um novo foco de preocupação voltou-se para a avaliação da qualidade de vida no grupo de pacientes transplantados. Os benefícios do transplante hepático sobre a qualidade de vida dos pacientes é um evento já demonstrado previamente em alguns estudos que utilizaram questionários genéricos de avaliação de qualidade de vida. A qualidade de vida em saúde também pode ser acessada através de questionários específicos, como o LDQOL (Liver Disease Quality of Life). Este é um instrumento voltado especificamente para sintomas relacionados às doenças hepáticas, desenvolvido nos Estados Unidos e recentemente traduzido para o Português e adaptado culturalmente para à população brasileira. Objetivo Aplicar este novo instrumento na população de pacientes em lista de espera de transplante de fígado e naqueles submetidos a transplante, reavaliando diferentes aspectos da qualidade de vida destes pacientes e avaliando o impacto da recidiva da doença de base após o transplante hepático. Método: Foram aplicados os questionários LDQOL e SF?36 a 126 pacientes em acompanhamento ambulatorial regular no Serviço de Transplante e Cirurgia do Fígado do Hospital das Clínicas da Universidade de São Paulo, dos quais 65 eram pacientes cirróticos em lista de espera de transplante de fígado e 61 deles eram pacientes submetidos a transplante hepático há pelo menos 6 meses e no máximo há 60 meses. Também foi aplicado o questionário SF-36 a um grupo de doadores de sangue sadios, pareados por sexo e idade e que funcionou como grupo controle. As avaliações, realizadas a partir da formação destes 3 grupos, incluiram a comparação da qualidade de vida entre cirróticos e transplantados, a comparação entre indivíduos saudáveis e portadores de hepatopatia e a influência de outros aspectos como etiologia da doença hepática, escore do MELD, classificação de Child-Pugh, presença de co-morbidades, tempo decorrido do transplante e efeito da recidiva da doença hepática sobre a qualidade de vida do paciente transplantado. O método estatístico aplicado foi o teste de Mann- Whitney. Resultados: As pontuações atingidas para os pacientes em lista de transplante hepático para mensuração da qualidade de vida foram significantemente mais baixas do que aquelas atingidas pelo grupo controle. Na comparação entre cirróticos com MELD <= 15 e cirróticos com MELD > 15, tanto o SF-36 como o LDQOL mostraram pior qualidade de vida nos pacientes com MELD mais elevado. A comparação entre indivíduos antes e depois do transplante evidenciou melhor qualidade de vida no grupo de pacientes transplantados. Isto ficou evidenciado tanto pelo LDQOL como SF-36. No grupo de pacientes pré-transplante, o questionário LDQOL mostrou maior comprometimento da qualidade de vida naqueles pacientes com cirrose por VHC, quando comparado a outras etiologias, enquanto o SF-36 não teve a mesma acurácia em demonstrar esta diferença. Nos pacientes transplantados, a recidiva da hepatite C determina comprometimento da qualidade de vida, quando avaliados pelo LDQOL, mas não pelo SF-36. Conclusões: O uso de um instrumento de medida de qualidade de vida - o LDQOL - pôde demonstrar, com maior acurácia, o seu comprometimento nos pacientes cirróticos, a melhora observada nos pacientes transplantados e o impacto negativo da recidiva da hepatite C no pós-transplante. / Liver transplantation has been established as the standard treatment for patients with end stage liver disease and for many years the outcomes of its procedure has been measured as mortality rates and biliary and infectious complications. More recently a new issue has been raised and many studies have been changing the focus to analyze the health related quality of life among the population of transplanted patients. A positive effect of liver transplantation on health-related quality of life (HRQOL) has been documented in many studies using generic instruments. Health-related quality of life can also be assessed with specific instruments, as the Liver Disease Quality of Life(LDQOL), a questionnaire targeted to symptoms of hepatic disease, that has been recently translated to Portuguese and culturally adapted to Brazilian population. Our aim was to reevaluate different aspects of HRQOL before and after liver transplantation with this new instrument, and determinate the impact of liver disease recurrence after the surgical procedure. Methods: The LDQOL and SF-36 questionnaires were applied to 126 patients at the Service of Transplant and Liver Surgery of Clinical Hospital of University of São Paulo, 65 of them on the transplant waiting list and 61 of them after 6 to 60 months of liver transplantation. It was also analyzed the quality of life, by using the SF-36 questionnaire, of health blood donors, paired by sex and age, to serve as control group. Multiple comparisons were made concerning etiology of cirrhosis, co-morbidities, MELD scores, time elapsed of transplant, recurrence of liver disease after liver transplantation, using the Mann-Whitney test. Results: HRQOL scores for patients waiting for transplantation were significantly lower than those for the control group. Patients with MELD scores > 15 showed worse healthrelated quality of life than patients with MELD scores <= 15, both with SF-36 and LDQOL. When the group of transplanted patients was compared with patients before transplant, an improvement of HRQOL was found in the transplanted group with both SF-36 and LDQOL. Quality of life in pretransplant patients was found to be worse in those with cirrhosis due to hepatitis C than in those with cirrhosis due to other etiologies; the reduction in quality of life was found to be greater using LDQOL than using SF-36. Transplanted patients with recurrence of hepatitis C had worse HRQOL when measured with LDQOL, but not with SF-36. Conclusions: LDQOL, a specific instrument for measuring quality of life is more reliable than SF-36 in showing quality of life impairment. A deterioration in health-related quality of life after recurrence of hepatitis C could be observed with LDQOL.
304

Proposição da assistência de enfermagem perioperatória aos pacientes com recidiva de câncer colorretal / Proposal to perioperative nursing care for patients with colorectal cancer recurrence

Lima, Mariza Silva de 17 September 2018 (has links)
Introdução: Muitos pacientes desenvolvem recidiva de câncer colorretal (CCR), que possui importância epidemiológica devido ao diagnóstico tardio e à dificuldade de acessibilidade à assistência de saúde. Objetivos: analisar as evidências científicas sobre a deiscência de anastomose intestinal em cirurgias por laparotomia e laparoscopia em pacientes com CCR, a recidiva de câncer colorretal e a assistência de enfermagem para pacientes com recidiva de CCR em tratamento cirúrgico; e realizar proposição de assistência de enfermagem perioperatória para esta clientela, com base nestas evidências científicas. Materiais e método: trata-se de revisão integrativa (RI), fundamentada na Prática Baseada em Evidências, realizada com as etapas de elaboração da pergunta e definição das estratégias de busca; elaboração de critérios de inclusão e exclusão; utilização de um instrumento para a coleta de dados da amostra; análise crítica dos estudos com avaliação do rigor e das características da amostra; síntese e interpretação dos resultados; e apresentação da RI. Para a busca da literatura científica utilizou-se os descritores colorectal neoplasms, laparoscopy, laparotmy e anastomoticleak; recurrence e colorectal neoplasm; nas base de dados Cumulative Index to Nursing and Allied Health Literature (CINAHL), Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS), Medical Literature Analysis and Retrieval System Online (MEDLINE), Biblioteca virtual COCHRANE, Índice Bibliográfico Español de Ciencias de la Salud (IBECS) e biblioteca virtual National Library of Medicine National Institutes of Health (PUBMED), mediante os critérios de inclusão e de exclusão, com seleção de oito e quatro artigos científicos, respectivamente; e com os descritores colorectal neoplasms, recurrence e nursing, seis artigos científicos. Resultados e discussão: a ocorrência de deiscência de anastomose, foi analisada em relação ao uso de novas técnicas cirúrgicas e maior densidade tecnológica para as terapêuticas adjuvantes, farmacológicas e os exames diagnósticos, que comprometem a mortalidade e sobrevida desta clientela. Em geral, os pacientes apresentam estadiamento avançado da doença, com realização de cirurgia tradicional pela condição clínica associada à comorbidades, maior risco cirúrgico e ampla ressecção intestinal, o que comprometem a sua recuperação fisiológica e psicossocial, além de maior possibilidade de recidiva ou metástases. Para a assistência à saúde desta clientela há necessidade de equipe multidisciplinar, priorizando-se a complexidade clínica, utilização de maior densidade tecnológica e seguimento especializado ao longo da sobrevivência. Há escassez de produção científica, sobre aspectos clínicos, terapêuticos e preventivos, principalmente da enfermagem. Conclusão: O enfermeiro deve ter domínio sobre fisiopatologia, terapêuticas e suas consequências, além de prognósticos e aspectos preventivos do CCR, para prestar assistência de enfermagem perioperatória para pacientes com CCR e familiares, com planejamento de intervenções procedimentais, educativas e psicossociais / Background: Many patients develop colorectal cancer recurrence (CCR), with epidemiological importance due to late diagnosis and the difficult access to health care. Objectives: To analyse scientific evidence on bowel anastomosis dehiscence in laparotomy and laparoscopy surgeries in patients with CCR, the colorectal cancer recurrence and the nursing care for patients with CCR relapse undergoing surgical treatment; and make the perioperative nursing care proposal to these patients, based on the scientific evidences cited. Method and materials: An integrated review (IR), grounded on the Evidence-Based Practice, developed in the following phases: creation of the question and definition of search strategies; creation of inclusion and exclusion criteria; the use of an instrument to collect sample data; critical analysis of the study and assessment of the rigor and characteristics of the sample; summary and interpretation of the results; and IR presentation. In the search for scientific literature, the descriptors colorectal neoplasms, laparoscopy, laparotomy and anastomotic leak; recurrence and colorectal neoplasm were used on the following databases: Cumulative Index to Nursing and Allied Health Literature (CINAHL), LatinAmerican and Caribbean Literatures on health Science (LILACS), Medical Literature Analysis and Retrieval System Online (MEDLINE), COCHRANE virtual library, Español de Ciencias de la Salud (IBECS) bibliographic index and National Library of Medicine National Institutes of Health (PUBMED) virtual library, using the inclusion and exclusion criteria, selecting 8 and 4 scientific articles, respectively; and 6 scientific articles with the descriptors colorectal neoplasms, recurrence e nursing. Results and discussion: the occurrence of anastomosis dehiscence was analysed in relation to the use of new surgical techniques and greater technological density for the therapeutics adjuvants, pharmacological and the diagnostic tests that affect the mortality and the survival of such patients. In general, patients present advanced staging of the disease with the practice of traditional surgery due to clinic condition associated to comorbidities, greater surgical risk and extensive intestinal resection, which impair their physiological and psychosocial recovery, in addition to a greater possibility of recurrence or metastasis. For the health care of such patients, it is necessary a multidisciplinary team, prioritising the clinical complexity, the use of higher technological density and specialised assistance throughout the survival. There is a shortage of scientific production on clinical, therapeutic and preventive aspects, particularly in nursing. Conclusion: Nurses shall master pathophysiology, therapeutics and their consequences, as well as the prognosis and preventive aspects of CCR in order to provide perioperative nursing care for patients with CCR and their family, with procedural, educational and psychosocial interventions
305

Envolvimento da ativação de PAFR frente à quimioterapia no fenômeno de repopulação de melanomas / Involvement of PAFR activation during chemotherapy in the melanoma repopulation phenomenon

Jacomassi, Mayara D\'Auria 04 December 2018 (has links)
Um dos desafios recorrentes na prática clínica da Oncologia é o processo de repopulação, no qual células tumorais resistentes à terapia são capazes de proliferar e reconstituir o tumor. No entanto, os mecanismos envolvidos neste fenômeno ainda foram pouco explorados, sendo necessário melhor compreendê-los para evitar a falha terapêutica. Melanomas são bons modelos para estudar repopulação devido às baixas taxas de sobrevida livre de progressão e às altas taxas de resistência às terapias associadas a este tipo de tumor sólido. Sabe-se que a exposição de células tumorais a condições estressoras do microambiente, como hipóxia e hipóxia/reoxigenação, bem como ao próprio tratamento antitumoral, são pressões seletivas frequentemente encontradas em tumores sólidos que favorecem a resistência às terapias e a repopulação tumoral. Estudos prévios indicam que a sinalização mediada pelo Fator de Ativação de Plaquetas (PAF), um lipídio bioativo relacionado à diversas funções fisiológicas, e de seu receptor, PAFR, está associada com a resistência de células de melanoma aos tratamentos citotóxicos e com crescimento tumoral. Portanto, este trabalho teve como objetivo investigar o envolvimento da sinalização de PAFR frente às condições estressoras descritas acima no fenômeno de repopulação de melanomas. Os resultados de espectrometria de massa indicaram que hipóxia aumentou a geração de PAF nas linhagens de melanoma humano SKmel05 e A375, mas não na A375M, embora este aumento não tenha sido observado após a reoxigenação. Além disso, mostraram que SKmel37 exibiu os maiores níveis basais de PAF, aumentando substancialmente sua geração em diferentes tempos de exposição à hipóxia e hipóxia/reoxigenação. Investigamos também a geração de outros ligantes de PAFR, porém nenhum deles foi encontrado nas amostras. Os resultados de detecção de PAFR por Western Blot e/ou citometria de fluxo revelaram que os níveis proteicos não foram modulados por estas condições em nenhuma das linhagens e que, em termos basais, SKmel37 e SKmel05 apresentaram os maiores níveis. Estas linhagens foram, portanto, submetidas a ensaios de proliferação, os quais evidenciaram que frente ao tratamento com o antagonista de PAFR, WEB2086, em condições de hipóxia e hipóxia/reoxigenação, apenas as células SKmel37 tiveram sua proliferação reduzida e morfologia associada à morte. Ensaios de incorporação de iodeto de propídio indicaram que o tratamento destas células expostas à hipóxia/reoxigenação com WEB2086 levou a acúmulo em SG2M, morte celular e sensibilização à cisplatina. Além disso, imunofluorescência de cortes congelados de tumores induzidos com SKmel37 revelou que houve acúmulo de PAFR em áreas hipóxicas e em seu entorno. Em relação ao modelo de exposição à tratamentos antitumorais, por sua vez, curvas de concentração e tempo com Vemurafenib mostraram que SKmel37 e A375 foram resistentes à droga, ao passo que SKmel05 e UACC62 foram sensíveis. Além disso, WEB2086 potencializou o efeito de morte induzido por Vemurafenib nas linhagens sensíveis, mas não afetou as resistentes. Considerando os aspectos clínicos de resposta inicial com posterior desencadeamento de repopulação, seguimos com as linhagens sensíveis e verificamos por citometria que esta droga aumentou ROS em ambas as linhagens, mas só aumentou PAFR extracelular na SKmel05. O tratamento combinado potencializou a geração de ROS e levou a ativação de caspase3/7 apenas na SKmel05. Esta linhagem foi então submetida a ensaios clonogênicos cujos resultados mostraram que o tratamento com Vemurafenib reduziu o número de clones e que WEB2086 não potencializou este efeito. Assim, o conjunto de resultados apresentados evidencia que a sinalização de PAFR participa dos desfechos de sobrevivência frente à hipóxia/reoxigenação e/ou tratamentos antitumorais, podendo, de alguma forma, contribuir com a repopulação de melanomas / One of the recurrent challenges in the clinical practice of Oncology is the process of repopulation, in which therapy-resistant tumor cells can proliferate and reconstitute the tumor. However, the mechanisms involved in this phenomenon were still little explored. The understanding of these events is, therefore, needed to avoid therapeutic failure. Melanomas are good models for studying repopulation due to the low rates of progression-free survival and the high rates of resistance to therapies associated to this type of solid tumor. It is known that the exposure of tumor cells to microenvironmental stress conditions, such as hypoxia and hypoxia/reoxygenation, as well as the exposure to antitumor treatment itself, are selective pressures frequently found in solid tumors that favor therapy resistance and tumor repopulation. Previous studies have indicated that the signaling mediated by the Platelet Activation Factor (PAF), a bioactive lipid related to various physiological functions, and its receptor, PAFR, is associated with resistance of melanoma cells to cytotoxic treatments and with tumor growth. Therefore, the aim of this study was to investigate the involvement of PAFR signaling upon the adverse conditions described above in the phenomenon of melanoma repopulation. Mass spectrometry results indicated that hypoxia increased the generation of PAF in human melanoma cell lines SKmel05 and A375, but not in A375M, although this increase was not observed after reoxygenation. In addition, they showed that SKmel37 exhibited the highest PAF basal levels, whose generation increased substantially after different times of hypoxia and hypoxia/reoxygenation exposure. We also investigated the generation of other PAFR ligands, but none were found in the samples. The results of PAFR detection by Western Blot and/or flow cytometry revealed that protein levels were not modulated by these conditions in any of the cell lines and that, at baseline, SKmel37 and SKmel05 showed the highest levels. These lines were therefore submitted to proliferation assays, which showed that the treatment with the PAFR antagonist, WEB2086, under conditions of hypoxia and hypoxia/reoxygenation, led to proliferation reduction and death-associated morphology in SKmel37 cells only. Propidium iodide incorporation studies indicated that the treatment of these cells exposed to hypoxia/reoxygenation with WEB2086 led to accumulation in SG2M, cell death and cisplatin sensitization. In addition, immunofluorescence of frozen sections of SKmel37-induced tumors revealed that PAFR was found accumulated in hypoxic areas and its surroundings. Regarding the model of exposure to antitumor treatments, concentration and time curves with Vemurafenib showed that SKmel37 and A375 were resistant to the drug, whereas SKmel05 and UACC62 were sensitive. In addition, WEB2086 potentiated the effect of Vemurafenib-induced death on sensitive cell lines but did not affect the resistant ones. Considering the clinical aspects of initial response with subsequent repopulation triggering, we continued using the sensitive cell lines and we verified by cytometry that this drug increased ROS in both cell lines but only increased extracellular PAFR in SKmel05. The combined treatment potentiated the generation of ROS and led to the activation of caspase3/7 in SKmel05 only. This cell line was then submitted to clonogenic assays whose results showed that treatment with Vemurafenib reduced the number of clones and that WEB2086 did not potentiate this effect. Thus, the set of results presented highlights that PAFR signaling participates in the survival outcomes upon hypoxia/reoxygenation and/or antitumor treatments, and may, in some way, contribute to the repopulation of mel
306

La maladie veineuse thromboembolique : étude des facteurs de risque de récidive / Venous thromboembolism : risk factors for recurrence

Olié, Valérie 24 May 2011 (has links)
A partir des données de deux études de cohortes hospitalières françaises (MEVE etFARIVE), nous nous sommes intéressés aux facteurs de risque de récidive de maladieveineuse thromboembolique (MVTE).Nous avons confirmé un excès de risque de récidive de MVTE chez les hommescomparés aux femmes et montré que cette relation dépendait en partie de l’âge, de lamutation du FV Leiden et de la prise d'hormones au premier événement. Une analyse enfonction du sexe a mis en évidence que l’âge, l’obésité et des niveaux élevés de D-dimèresaugmentaient significativement le risque de récidive de MVTE chez les femmes. Par ailleurs,contrairement aux estrogènes oraux, les estrogènes transdermiques seuls ou combinés à laprogestérone micronisée n'exposaient pas les femmes ménopausées à un risque accru derécidive de MVTE. Chez les hommes, la mutation du facteur V Leiden, un antécédent familialde maladie artérielle et un premier événement idiopathique étaient des facteurs de risqueindépendants de récidive.L'identification de profils de risque différents en fonction du sexe pourrait permettreune meilleure stratification du risque de récidive de MVTE. Ces résultats devraientcontribuer à améliorer la prise en charge de la maladie par une évaluation individuelle de ladurée optimale du traitement anticoagulant. De plus, une bonne sécurité d’emploi desestrogènes transdermiques seuls ou combinés à la progestérone micronisée ouvre desperspectives cliniques intéressantes dans le traitement des troubles sévères de laménopause chez des patientes avec un antécédent personnel de MVTE.Mots / Based on data from two French hospital cohort studies, we investigated the riskfactors for recurrent venous thromboembolism (VTE).We confirmed the higher risk of recurrent VTE among men compared with womenand we suggested that this relation depended on age, Factor V Leiden mutation andhormone-related first event. A sex-specific analysis showed that advancing age, obesity andelevated D-dimer significantly increased the risk of recurrent VTE in women. Moreover, oralbut not transdermal estrogens, were associated with a higher risk of recurrent VTE amongpostmenopausal women. In men, factor V Leiden mutation, family history of arterial diseaseand an idiopathic first event were independent risk factors for VTE recurrence.The identification of sex-specific risk factors provides a new insight to riskstratification for VTE recurrence. These results could improve the prevention of this diseaseby an individual assessment of the optimal duration of anticoagulation therapy. In addition,our results provide first evidence supporting the safety of transdermal estrogens alone orcombined with micronized progesterone with respect to VTE recurrence risk. These datacould have important clinical implications for women with personal history of VTE whorequire hormone therapy for severe postmenopausal symptoms.
307

Femoral and Inguinal Hernia : How to Minimize Adverse Outcomes Following Repair

Dahlstrand, Ursula January 2011 (has links)
Groin hernia is common, and each year 200 repairs per 100 000 adult inhabitants are performed in Sweden. Groin hernias are either inguinal or femoral (2-4%). Elective repair is not associated with an excess mortality, but adverse outcomes include recurrence and long-term pain. Emergency procedures have a 4% mortality rate with an increased risk for bowel resection and postoperative complications. The aim of this thesis was to identify risk factors for adverse outcomes and to propose measures to improve groin hernia treatment. Twenty-three per cent of female hernias were femoral. Thirty-six per cent of femoral hernias, and 5% of inguinal hernias, have emergency procedures. Females (OR 1.47) and patients above 65 years-of-age (OR 2.24) were at higher risk for emergency repair. Bowel resection was performed in 23% of emergency femoral repairs, and the 30-day mortality was 10 times that of an age- and gender-matched population. The majority of emergency patients were unaware of their hernia, and one third had previously had no groin symptoms. Femoral repairs were at larger risk for recurrence than inguinal repairs. The surgical techniques with least risk for recurrence were preperitoneal mesh repairs (open HR 0.28, and laparoscopic HR 0.31). Long-term pain was present in 24% of femoral hernia patients, of whom 5.5% described pain interfering with daily activities. The only factor predicting the risk for long-term pain was pain preoperatively. Pain decreased with time. In a randomized study on inguinal hernia, TEP resulted in less pain six weeks after surgery than Lichtenstein repair performed under local anesthesia (LLA). TEP patients were to a larger extent able to perform sporting activities. No difference was seen in intra-operative complications. Femoral hernias should be given high priority for repair and preperitoneal techniques should be used. Earlier diagnosis, in the elective setting, is probably difficult to attain. Heightened awareness in the emergency department is required. TEP is safe, and results in less pain than LLA six weeks after surgery. A widening of indications for TEP in primary inguinal hernia repair is justifiable.
308

IgA Nephropathy – Mucosal Immunity and Treatment Options

Smerud, Hilde Kloster January 2012 (has links)
In the present studies we have explored the link between food hypersensitivity and IgA nephropathy (IgAN) and evaluated treatment options in primary and recurrent disease. Approximately one third of our IgAN patients had a rectal mucosal sensitivity to gluten, as demonstrated by increased local mucosal nitric oxide production and/or myeloperoxidase release after gluten challenge. The gluten sensitivity seemed to be an innate immune reaction unrelated to the pathogenesis of celiac disease. Approximately half of the patients had a rectal mucosal sensitivity to soy or cow’s milk (CM). The levels of IgG antibodies to alfa-lactalbumin, beta-lactoglobulin and casein were significantly higher in CM sensitive as compared with non-sensitive IgAN patients, indicating that an adaptive immune response might be involved in addition to the innate immune reaction observed. With the knowledge of gastrointestinal reactivity enteric treatment was considered as a potential new treatment approach of IgAN. A 6-month prospective trial demonstrated proof-of-concept for the use of enteric budesonide targeted to the ileocaecal region of IgAN patients. We observed a modest, but significant reduction in urine albumin, a minor reduction of serum creatinine and a modest increase of eGFR calculated by the MDRD equation. eGFR calculated from the Cockcroft-Gault formula and cystatin C was not changed. In a retrospective study recurrence of IgAN and graft loss was evaluated in Norwegian and Swedish patients having received a primary renal transplant due to IgAN. Adjusting for relevant covariates, a multiple Cox-regression analysis on time to IgAN recurrence showed that use of statins was associated with reduced risk of recurrence and reduced risk of graft loss. The time lag from diagnosis to first transplantation and female gender were also associated with lower risk of recurrence. Improved graft survival was associated with related donor, low donor age and no or low number of acute rejection episodes.
309

The study of chaotic phase synchronization of nonlinear electronic circuits and solid-state laser systems

Lin, Chien-Hui 12 July 2012 (has links)
We study the chaotic phase synchronization (CPS) between the external periodically driving signals and the nonlinear dynamic systems. The periodical signal was applied to drive the Chua circuit system with two-scroll attractor and the four-scroll attractor circuit system. The phase synchronization between the outputs of these two circuit systems and the driving signals were investigated. Besides, the chaotic phase synchronization of the periodically pump-modulated microchip Nd:YVO4 laser and the microchip Nd:YVO4 laser with optical feedback were also examined in this study. Phase synchronization (PS) transition of these periodically driven nonlinear dynamic systems exhibited via the stroboscopic technique and recurrence probability. The recurrence probability and correlation probability of recurrence were utilized to estimate the degree of PS. In this thesis, the degree of PS was studied by taking into account the amplitude and frequency of the external driving signal. The experimental compatible numerical simulations also reflected the fact that the Arnold tongues are experimentally and numerically exhibited in the periodically driven nonlinear dynamic systems.
310

Carotid stenosis / Karotisstenos

Johansson, Elias January 2011 (has links)
Carotid stenosis is one of several causes of ischemic stroke and entails a high risk of ischemic stroke recurrence. Removal of a carotid stenosis by carotid endarterectomy results in a risk reduction for ischemic stroke, but the magnitude of risk reduction depends on several factors. If the delay between the last symptom and carotid endarterectomy is less than 2 weeks, the absolute risk reduction is &gt;10%, regardless of age, sex, or if the degree of carotid stenosis is 50–69% or 70–99%. Thus, speed is the key. However, if many patients suffers an ischemic stroke recurrence within the first 2 weeks of the presenting event, an additional benefit is likely be obtained if carotid endarterectomy is performed even earlier than within 2 week after the presenting event. Carotid endarterectomy for asymptomatic carotid stenoses carries a small risk reduction for stroke. Screening for asymptomatic carotid stenosis requires a prevalence of &gt;5% in the examined population, i.e., higher than in the general population; however, directed screening in groups with a prevalence of &gt;5% is beneficial. The aims of this thesis were to investigate the length of the delay to carotid endarterectomy, determine the risk of recurrent stroke before carotid endarterectomy, and determine if a calcification in the area of the carotid arteries seen on dental panoramic radiographs is a valid selection method for directed ultrasound screening to detect asymptomatic carotid stenosis. Consecutive patients with a symptomatic carotid stenosis who underwent a preoperative evaluation aimed at carotid endarterectomy at Umeå Stroke Centre between January 1, 2004–March 31, 2006 (n=275) were collected retrospectively and between August 1, 2007–December 31, 2009 (n=230) prospectively. In addition, 117 consecutive persons, all preliminarily eligible for asymptomatic carotid endarterectomy and with a calcification in the area of the carotid arteries seen on panoramic radiographs, were prospectively examined with carotid ultrasound. The median delay between the presenting event and carotid endarterectomy was 11.7 weeks in the first half year of 2004, dropped to 6.9 weeks in the first quarter year of 2006, and had dropped to 3.6 weeks in the second half year of 2009. The risk of ipsilateral ischemic stroke recurrence was 4.8% within 2 days, 7.9% within 1 week, and 11.2% within 2 weeks of the presenting event. For patients with a stroke or transient ischemic attack as the presenting event, this risk was 6.0% within 2 days, 9.7% within 1 week, and 14.3% within 2 weeks of the presenting event. For the 10 patients with a near-occlusion, the risk of ipsilateral ischemic stroke recurrence was 50% at 4 weeks after the presenting event. Among the 117 persons with a calcification in the area of the carotid arteries seen on panoramic radiographs, eight had a 50–99% carotid stenosis, equalling a prevalence of 6.8% (not statistically significantly over the pre-specified 5% threshold). Among men, the prevalence of 50–99% carotid stenosis was 12.5%, which was statistically significantly over the pre-specified 5% threshold. In conclusion: The delay to carotid endarterectomy was longer than 2 weeks. Additional benefit is likely to be gained by performing carotid endarterectomy within a few days of the presenting event instead of at 2 weeks because many patients suffer a stroke recurrence within a few days; speed is indeed the key. The finding that near-occlusion entails an early high risk of stroke recurrence stands in sharp contrast to previous studies; one possible explaination is that this was a high-risk period missed in previous studies. The incidental finding of a calcification in the area of the carotid arteries on a panoramic radiograph is a valid indication for carotid ultrasound screening in men who are otherwise eligible for asymptomatic carotid endarterectomy.

Page generated in 0.0518 seconds