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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.
191

Characterization of Liver Damage Mechanisms Induced by Hepatitis C Virus

Soare, Catalina P. January 2011 (has links)
Hepatitis C Virus (HCV) is one of the most important causes of chronic liver disease, affecting more than 170 million people worldwide. The mechanisms of hepatitis C pathogenesis are unknown. Viral cytotoxicity and immune mediated mechanisms might play an important role in its pathogenesis. HCV infection and alcohol abuse frequently coexist and together lead to more rapid progression of liver disease, increasing the incidence and prevalence of cirrhosis and hepatocellular carcinoma. The cytopathic effect of HCV proteins, especially the core, E1 and E2 structural proteins, which induce liver steatosis, oxidative stress and cell transformation may be amplified by alcohol abuse. The purpose of this study was to characterize the liver damage mechanisms induced by HCV structural proteins and alcohol and to determine the potential molecular mechanism(s) that may promote chronic, progressive liver damage. A transgenic mouse model expressing HCV core, E1 and E2 was used to investigate whether alcohol increased HCV RNA expression. Real-time RT-PCR analysis of genes involved in lipid metabolism and transport confirmed their abnormal expression in the alcohol-fed transgenic mice. In addition, light and electron microscopy analysis were performed on liver tissues of transgenic mice on an alcoholic diet versus those on a normal diet, in order to identify histological changes. The severe hepatopathy in HCV transgenic mice was exacerbated by alcohol. Mitochondria and endoplasmic reticulum had severe abnormalities in the electron microscopy analysis. The second part of this study focused on adaptive immune responses, which may also play an important role in HCV pathogenesis. I focused my analysis on dendritic cells (DC), which have been the main suspects to explain immune impairment in HCV infection. Their powerful antigen-presenting function allows them to stimulate the antiviral response of CD4+ and CD8+ T cells, the effector cells of the immune system. This unique function of the DC makes them possible targets for immune evasion by the Hepatitis C virus. In this study, DCs were generated from mouse bone marrow cells. I investigated their maturation capacity in the presence of structural proteins of HCV. The impact of HCV core/E1/E2 polyprotein on DCs cytokine expression and ability to activate T-cell lymphocytes was also analyzed. A dysfunctional CD4 T cell response was observed after exposure of DCs to core/E1/E2 polyprotein, indicating inefficient CD4 priming, which might lead to chronic HCV infection in humans. The presence of the core/E1/E2 polyprotein reduced the DC maturation capacity and the expression of certain cytokines (IL-12, IFNg, IL-6, MCP-1) important for stimulation and chemotaxis of T cells and other immune cells. My studies contribute to the understanding of HCV pathogenesis and may have implications to the development of better therapies for HCV infection.
192

Examining MicroRNAs as Regulators of Hepatic Lipid Homeostasis and Hepatitis C Virus Replication

Singaravelu, Ragunath January 2016 (has links)
Hepatitis C virus (HCV) infection is a leading cause of liver transplantation and hepatocellular carcinoma worldwide. HCV, like all obligate parasites, relies on host pathways to facilitate its pathogenesis. In particular, the virus possesses an intimate link with hepatic lipid metabolism, promoting a lipid-rich cellular environment conducive to HCV propagation. Clinically, these metabolic perturbations manifest as steatosis in over 50% of patients. The majority of research to-date examining how the virus co-opts hepatic lipid pathways has been focused on coding genes and their protein products. MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression, which have been implicated in virtually every cellular process. Through interactions with partially complementary mRNAs, each individual miRNA has the capacity to repress the expression of hundreds of genes and induce significant regulatory effects. Herein, we demonstrate that hepatic miRNAs, including miR-7, miR-27a/b, miR-130b, and miR-185, act as crucial regulatory molecules to the maintenance of hepatic lipid homeostasis. These miRNAs cooperate to regulate fatty acid and cholesterol metabolism. HCV modulates the expression of a subset of these miRNAs (miR-27a/b, miR-130b, and miR-185) to promote hepatocellular lipid accumulation and the HCV life cycle. There appears to be a broad viral requirement for lipids, and the mammalian innate immune response strategically targets host metabolic pathways to restrict virus’ access to key lipid species. We demonstrate that 25-hydroxycholesterol, a broadly anti-viral oxysterol produced as part of the innate anti-viral response, activates miR-185 expression in the liver to deplete virus infected cells of lipids. HCV appears to actively counteract this anti-viral response by suppressing miR-185 expression. Collectively, our results highlight the role of microRNAs in hepatic lipid metabolism and the immunometabolic response to viral infection.
193

Investigating Hepatitis C Virus Interactions with Host Lipid Pathways that are Critical for Viral Propagation Using Small Molecule Inhibitors and Chemical Biology Methods

Lyn, Rodney January 2013 (has links)
Hepatitis C virus (HCV) is remarkably capable of efficiently hijacking host cell pathways including lipid metabolism in the liver in order to create pro-viral environments for pathogenesis. It is becoming increasingly clear that identifying small molecule inhibitors that target host factors exploited by the virus will expand available HCV treatment options. As such, a thorough understanding of host-virus interactions is critical to the development of alternative therapeutic strategies. Hepatic lipid droplets (LDs) are recruited by HCV to play essential roles in the viral lifecycle. The intracellular location of LDs is modified upon interacting with viral structural core protein. This enables formation of platforms that support viral particle assembly. Because these interactions are non-static, capturing its dynamic processes in order to better understand viral assembly can be achieved with label-free molecular imaging enhanced with live-cell capabilities. Chemical biology approaches that includes CARS microscopy employed in a multi-modal imaging system was used to probe interactions between HCV and host LDs. By successfully tracking LD trajectories, we identified core protein’s ability to alter LD speed and control for LD directionality. Using protein expression model systems that allowed for simultaneous tracking of core protein and LDs, our data revealed that mutations in the core protein region that vary in hydrophobicity and LD binding strengths, are factors that control for differential modulation of LD kinetics. Furthermore, we measured bidirectional LD travels runs and velocities, and observed critical properties by which core protein induces LD migration towards regions of viral particle assembly. Given that many steps in the HCV lifecycle are directly linked to host lipid metabolism, it is not surprising that disrupting lipid biosynthetic pathways would negatively affect viral replication. From this outlook, we explored small molecule inhibitors that targeted several lipid metabolic pathways to study its antiviral properties. Using fluorescent probes covalently labeled to viral RNA, we captured the visualization of disrupted replication complexes upon antagonizing nuclear hormone receptors that are linked to regulating lipid homeostasis. Correspondingly, biochemistry and molecular imaging techniques were also employed to identify novel antiviral mechanisms of small molecule inhibitors that target additional HCV-dependent lipid metabolic pathways.
194

Investigating Host-Viral Interactions in Liver Lipid Homeostasis and HCV Pathology

Delcorde, Julie January 2014 (has links)
Hepatitis C virus (HCV) infects an estimated 170 million people worldwide and is a major cause of chronic hepatitis and hepatocellular carcinoma. As there are limited treatment options, the elucidation of novel host-viral interactions during HCV pathogenesis will be critical for the development of new therapeutics. My thesis work has identified cell death-inducing DFF45-like effector B (CIDEB) as a host factor that is disregulated during HCV infection, and has delineated the relevance of CIDEB’s dual roles in apoptosis and lipid metabolism in the context of the HCV lifecycle. Moreover, additional host factors necessary for the HCV lifecycle were investigated using unnatural amino acid (UAA) technology. With this technique, the photo-cross-linking UAA p-azido-phenlyalanine (AZF) and 3’-azibutyl-N-carbamoyl-lysine (Abk) were incorporated into viral proteins by expanding the genetic code of the host organism. This conferred diverse physicochemical and biological properties to these proteins that were exploited to investigate protein structure and function in vitro and in vivo. In summary, gaining insight into the numerous host-viral interactions that take place during HCV infection will both advance our understanding of HCV pathogenesis and uncover potential therapeutic targets.
195

Risk Factors and Associations for Hepatitis C Infection among Hispanic/Latino Intravenous Drug Users in Miami-Dade County, Florida

Rodriguez, Arturo E 05 November 2012 (has links)
Hepatitis C infection (HCV) continues to disproportionately affect Hispanics/Latinos in the United States. Hispanic/Latino intravenous drug users (IDUs), because of their risky injection and sexual behaviors, are prone to HCV infection and rapid transmission of the virus to others via several routes. With a prevalence rate of approximately 75% among IDUs, it is imperative that transmission of HCV be prevented in this population. This study aims to examine the associations between demographic, injection and sexual risk factors to HCV infection in a group Hispanic/Latino IDUs in Miami-Dade County, Florida. Preliminary unadjusted results in this sample reveal that age (OR=4.592, p=0.004), weekly injection (OR=5.171, p=0.000), daily injection frequency (OR=3.856, p=0.000) and use of a dirty needle (OR=2.320, p= 0.006) were all significantly associated with HCV infection. Being born outside the U.S. was significantly negatively associated with HCV infection (OR=0.349, p=0.004). Additionally, having two or more sex partners in the past three months (OR=0.472, p=0.014) was negatively associated with HCV infection. After adjusting for all other variables, older age (AOR=7.470, p=0.006), weekly injection (AOR=3.238, p=0.007) and daily injection frequency (AOR=2.625, p=0.010) were all significantly associated with HCV infection. Being born outside the U.S. (AOR=0.369, p=0.019) was a significant protective factor for HCV infection, along with having two or more sex partners in the past three months (AOR=0.481, p=0.037). When analyzing the significant variables in a backward regression model, having 2 or more sex partners in the past three months was not significant at the p
196

Prevalência e características clínico epidemiológicas de gestantes com hepatite C atendidas no CAISM - UNICAMP = Prevalence and clinical epidemiological features of hepatitis C infection among pregnant women at CAISM - UNICAMP / Prevalence and clinical epidemiological features of hepatitis C infection among pregnant women at CAISM - UNICAMP

Schweller, Mariana Salhab Dall' Aqua, 1986- 27 August 2018 (has links)
Orientador: Helaine Maria Besteti Pires Mayer Milanez / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-27T21:43:52Z (GMT). No. of bitstreams: 1 Schweller_MarianaSalhabDall'Aqua_M.pdf: 1766000 bytes, checksum: e03c3a8a2bf2836ec2f7e49bc907e1fd (MD5) Previous issue date: 2015 / Resumo: Introdução: A Hepatite C é um dos maiores problemas atuais de saúde pública, com mais de 150 milhões de pessoas contaminadas. A evolução da doença geralmente é assintomática e suas complicações são cirrose, fibrose hepática e hepatocarcinoma. Na gestação o tratamento não é recomendado, com possível piora da doença no período. Objetivo: identificar a prevalência de Hepatite C em gestantes que realizaram acompanhamento pré-natal no Hospital da Mulher Professor José Aristodemo Pinotti - Centro de Atenção Integral à Saúde da Mulher (CAISM) da UNICAMP, analisando dados clínicos, epidemiológicos e resultados perinatais. Metodologia: estudo de corte transversal cuja amostra foi composta por gestantes atendidas nos ambulatórios de pré-natal do CAISM entre 2005 e 2014 com sorologia positiva para Hepatite C. As pacientes foram identificadas através de listas informatizadas do serviço, e seus prontuários levantados para análise de dados sociodemográficos, epidemiológicos e desfechos perinatais. A análise dos dados foi feita através da distribuição percentual ou de médias. Resultados: na população de 29.327 gestantes atendidas pelo pré-natal entre 2005 e 2014, a prevalência de Hepatite C foi de 0,2%. Das 47 mulheres incluídas no estudo, a idade média foi de 32,5 anos, houve 49% de prevalência de baixa escolaridade, metade das participantes não planejaram a gestação, sendo que 38% destas não faziam uso de métodos contraceptivos. Além disso, 34% apresentaram coinfecção pelo HIV e 34% relataram uso de drogas. O número médio de gestações por paciente foi 3. Não se observou um pior desfecho perinatal, com peso médio de 2827,5 gramas ao nascimento e idade gestacional média de 39 semanas e 4 dias. Conclusões: Entre as pacientes infectadas pelo vírus C, observamos maior prevalência da raça branca, baixa escolaridade e coinfecção com HIV. Como principais fatores de risco para contaminação pela doença, foram identificados o uso de drogas, histórico de transfusões sanguíneas e a coinfecção com o HIV. Além disso, foram observadas maiores taxas de aborto, cesáreas e prematuridade neonatal em relação a outros estudos, fatores relacionados ao aumento da morbimortalidade materna, fetal e neonatal / Abstract: Introduction: Hepatitis C is a leading public health problem, with more than 150 million people infected. Disease evolution is usually asymptomatic, and complications are cirrhosis, liver fibrosis and hepatocellular carcinoma. Treatment is not recommended during pregnancy, but it may influence disease evolution. Objective: To identify Hepatitis C prevalence in pregnant women attended at Professor Doctor José Aristodemo Pinotti Women's Integrated Healthcare Center (CAISM) of the UNICAMP Medical School during prenatal period, analyzing clinical and epidemiological data, including perinatal outcomes. Methods: Authors performed a cross-sectional study with pregnant women who tested positive for Hepatitis C and gave birth at CAISM, between 2005 and 2014. Demographic, epidemiological and perinatal data were extracted from each patient¿s hospital records. Data analysis was made through media or percentage distribution. Results: Among 29.327 women treated at CAISM between 2005 and 2014, Hepatitis C prevalence was 0,2%. The mean maternal age at delivery was 32.5 years, 49% had low education and 49% did not plan the pregnancy. Among them, 38% did not use contraceptive methods. In addition, 34% had coinfection with HIV and 34% reported use of drugs. The average number of pregnancies per woman was 3, and there was no significant evidence of disease influence in pregnancy outcomes. Newborns¿ average weight was 2,827.5 grams, and the average of the gestational age was 39 weeks and 4 days. Conclusions: Among patients infected with Hepatitis C, there was predominance of the white race, low education and HIV coinfection. Drug addiction, blood transfusions and HIV co-infection were the main risk factors for contamination. When compared with other similar studies, this study found higher rates of abortion, cesarean sections and neonatal prematurity. These factors are associated with perinatal morbidity and mortality / Mestrado / Saúde Materna e Perinatal / Mestra em Ciências da Saúde
197

Busca de fatores genéticos associados à resposta ao tratamento do HCV genótipo 3. / Search for genetic factors associated with treatment response in HCV genotype 3.

Alexandre La Luna 30 July 2012 (has links)
Recentemente estudos demonstraram que os SNPs (polimorfismos de base única) rs8099917 e rs12979860 localizados próximos ao gene da IL28B explicam a variação de resposta à infecção e tratamento do paciente contra o genótipo 1 do HCV, porém não para o genótipo 3 deste vírus. Este trabalho encontrou associação significativa entre resposta à infecção devida ao genótipo 3 pelo tratamento (PEG-INF e RBV) e o polimorfismo rs8099917 em uma amostra da população de Santos - SP. Para o polimorfismo rs12979860, esta associação somente foi encontrada ao se parear indivíduos para sexo, idade e grau de fibrose hepática, demonstrando a importância da retirada de efeitos de estratificação neste tipo de análise. Estes resultados se confirmam ao se agregar dados de uma população proveniente da Bahia em uma meta-análise. Além disso, fez-se um estudo GWAS a fim de se conhecer outras variações genéticas envolvidas nessa resposta. Esta análise indicou a existência de alguns SNPs candidatos com sugestão de associação, dentre eles a tiroglobulina, relacionada aos hormônios da tireóide. / Recently, studies have shown that SNPs (single nucleotide polymorphisms) rs8099917 and rs12979860, located near the gene IL28B explain the changes in the response to infection and treatment of a patient against the HCV genotype 1, but not for the genotype 3 of the virus. This study found a significant association between response to infection due to treatment by genotype 3 (PEG-INF and RBV) and the rs8099917 polymorphism in a population sample from Santos - SP. To the rs12979860 polymorphism, this association was only found when individuals are paired for sex, age and degree of hepatic fibrosis, demonstrating the importance of the withdrawal effects of stratification in this type of analysis. These results confirm the aggregate data from a population of Bahia in a meta-analysis. In addition, a GWAS was made in order to search other genetic variations involved in this response. This analysis indicated the existence of some candidate SNPs with suggestion of association, including thyroglobulin, thyroid hormones related to.
198

THE COST-EFFECTIVENESS OF TREATING OR NOT TREATING HEPATITIS C GENOTYPE-1 BY STAGE IN THE LOUISIANA MEDICAID POPULATION

January 2018 (has links)
acase@tulane.edu / Background It is estimated 3 to 5 million individuals in the U.S. are chronically infected with the Hepatitis C virus (HCV). (Durham DP, 2016) More than 12,000 deaths occur annually in the U.S. as a result of HCV-related liver disease. (Wieland A, 2015) The cost of treatment medication for an individual with HCV genotype-1 is approximately $100,000 for 12 weeks of therapy. (Reau N, 2014) The exorbitant cost of HCV treatment has led to fears that many who could benefit from treatment will not receive it considering many with HCV are uninsured or have Medicaid. Purpose The purpose of this study is to quantify the cost, cost-effectiveness, and adverse outcomes associated with denying or delaying HCV treatment among the Louisiana Medicaid (LA-Medicaid) HCV GT-1 population. Methodology This project evaluates the cost and cost-effectiveness of treating HCV compared to not treating; initiating early treatment compared to late treatment and HCV-related health outcomes. A decision tree and Markov model simulates progression through the various states of health involved in progressive HCV disease, including death (hepatic and other causes). Results Don’t Treat/Treat Comparison Treatment was generally cost-effective, exhibiting an incremental cost-effectiveness ratio (ICER) of $21,670/life-year and $37,067/QALY (Quality-Adjusted Life-Years) gained. Optimal Treatment Stage Comparison Treatment of a person at F0 was cost effective, exhibiting an ICER of $6,482/QALY and $6,194/year of life compared to not treating at all and treating at F1, F2, F3, F4 or after LT. Conclusion Treatment of HCV-infected patients without liver fibrosis or in early stages of liver fibrosis appear to be more cost-effective than treating in advance stages of liver fibrosis or denying treatment. / 1 / Dwana Green
199

Síntesis asimétrica de prolinas polisustituidas mediante reacciones 1,3-dipolares con iluros de azometino

Retamosa, Maria de Gracia 21 November 2008 (has links)
No description available.
200

Avaliação da Variabilidade de uma Biblioteca de Anticorpos construída a partir de sangue de pacientes com Hepatite C Crônica com diferentes Graus de Fibrose

Silva, Cristiane Nonato da January 2019 (has links)
Orientador: Rejane Maria Tommasini Grotto / Resumo: A progressão da fibrose hepática somada à infecção pelo vírus da hepatite C (VHC) tem sido associada à resposta imunológica permanente. O estudo no repertório de anticorpos Anti-VHC na progressão da fibrose hepática foi explorado através de ferramentas de sequenciamento em larga escala (NGS) possibilitando uma análise de repertórios altamente variáveis como as porções variáveis VH (cadeia pesada) e Vk (cadeia leve) das imunoglobulinas, e a determinação de famílias e subfamílias dos genes V-D-J associadas à resposta humoral encontrada nas diferentes fases da doença proporcionam uma ferramenta importante no entendimento da resposta imune frente à infecção viral pelo VHC. As porções VH e Vk das imunoglobulinas foram obtidas a partir da amplificação de RNA de sangue de paciente VHC positivos e com diferentes graus de fibrose, e sequenciadas na plataforma Illumina® Miseq, fornecendo uma grande variabilidade de sequências que foram pré-processadas por ferramentas de bioinformática e analisadas em dois bancos de anticorpos diferentes: IgBlast (NCBI) e IMGT® quanto às famílias e subfamílias mais expressas. A expressão restrita de algumas famílias e subfamílias: IGHV1, IGHV3, IGHV4 e subfamílias já descritas em vários estudos associados ao VHC corrobora com nossos achados de que existe uma tendência do uso de algumas subfamílias como: IGHV1-2, IGHV1-8, IGVH1-69, IGHV3-11, IGHV3-21, IGHV3-23, IGVH3-30, IGHV4-4, IGHV4-34 IGHV4-39 na cadeia pesada; assim como IGkV3-15 e IGkV3-20 na cadei... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The progression of hepatic fibrosis in the hepatitis C virus (HCV) infection has been linked with permanent immune response. The study in the repertoire of Anti-HCV antibodies in the progression of hepatic fibrosis was analysed for large-scale sequencing (NGS) tools enabling a highly variable analysis such as the VH (heavy chain) and Vk (light chain) portions of immunoglobulins and the determination of families and subfamilies of the V-D-J genes in the humoral response found in the different phases of the disease, a great tool in the understanding of the immune response to HCV viral infection. The VH and V portions of the immunoglobulins were obtained from the amplification of HCV positive HCV patient blood with different degrees of fibrosis and sequenced on the Illumina® Miseq platform, providing a large sequence variability that was preprocessed by tools of bioinformatics and analyzed in two different antibody banks: IgBlast (NCBI) and IMGT® for the most expressed families and subfamilies. The restricted expression of some families: IGHV1, IGHV3, IGHV4 and subfamilies already described in several HCV-related studies confirm our findings that there is a tendency to use some subfamilies, such as: IGHV1-2, IGHV1-8, IGVH1- 69, IGHV3-11, IGHV3-21, IGHV3-23, IGVH3-30, IGHV4-4, IGHV4-34 IGHV4-39 in the heavy chain; as well as IGkV3-15 and IGkV3-20 in the light chain, but the subfamilies: IGHV1-8, IGHV3-11, IGHV4-39, IGkV1-5, IGkV1-12, IGkV1-39 were also among the most expressed, i... (Complete abstract click electronic access below) / Mestre

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