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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.
91

Pesquisa de marcadores sorológicos e moleculares da infecção pelo Vírus da Hepatite E (HEV) em indivíduos portadores do Vírus da Imunodeficiência Humana (HIV) / Serological and molecular markers of hepatitis E virus infection (HEV) in HIV-infected individuals

Ariana Carolina Ferreira 28 April 2016 (has links)
A infecção pelo HEV é reconhecida como um considerável problema de saúde pública em diversas regiões do mundo. Embora caracterizada como uma infecção benigna com um curso evolutivo autolimitado, recentes estudos têm mostrado sua evolução para cronicidade em indivíduos imunocomprometidos. Além disso, tem sido verificado que nesses indivíduos a infecção crônica pelo HEV pode evoluir para fibrose hepática progressiva, culminando com o desenvolvimento de cirrose. Não existem dados acerca da prevalência da infecção pelo HEV em pacientes infectados pelo HIV no Brasil, onde a circulação deste vírus tem sido demonstrada em diversos grupos de indivíduos imunocompetentes e, até mesmo, em alguns animais provenientes de diferentes regiões do país. Com base nisso, este trabalho teve como objetivo estimar a prevalência de marcadores sorológicos e moleculares da infecção pelo HEV, bem como a padronização de uma PCR em tempo real para a detecção e quantificação da carga viral do HEV na população de soropositivos da cidade de São Paulo. Foram incluídos neste estudo soro e plasma de pacientes infectados pelo HIV (n=354), que foram divididos em grupos de acordo com a presença ou ausência de coinfecção pelos vírus das hepatites B (HBV) e C (HCV). Essas amostras foram coletadas entre 2007 e 2013. Anticorpos anti-HEV IgM e IgG foram pesquisados pela técnica de ELISA (RecomWell HEV IgM/ IgG - MIKROGEN®), e, em alguns casos, confirmados por Immunoblotting (RecomLine HEV IgM/ IgG - MIKROGEN®). Todas as amostras foram submetidas à pesquisa de HEV RNA através da PCR em tempo real padronizada. Cerca de 72% dos indivíduos avaliados pertenciam ao sexo masculino. A média de idade entre a população analisada foi de 48,4 anos. Os anticorpos anti-HEV IgM e IgG foram encontrados em 1,4% e 10,7% dos indivíduos dessa população, respectivamente. Apenas dois pacientes apresentaram positividade simultânea para anti-HEV IgM e IgG. Não houve diferença estatisticamente relevante quanto à presença de marcadores sorológicos nos grupos de estudo. Além disso, foi detectado o HEV RNA em 10,7% das amostras analisadas, entre as quais, seis apresentaram simultaneamente algum marcador sorológico (5 anti-HEV IgG e 1 IgM). A presença deste marcador foi predominante no grupo de pacientes com coinfecção pelo HCV. Através deste trabalho pôde-se constatar, portanto, que o HEV é circulante entre a população de infectados pelo HIV em São Paulo, e que o seguimento desses pacientes se faz necessário dado a possibilidade de progressão para infecção crônica e cirrose / HEV infection is recognized as a significant public health problem in different world regions. Although initially characterized as a benign infection with selflimited course, recent studies have showing its evolution to chronicity in immunocompromised individuals. Furthermore, in these individuals the chronic infection can develop progressive liver fibrosis leading to cirrhosis. There are no data regarding prevalence of HEV infections in HIV- infected patients in Brazil, where the circulation of this virus has been demonstrated in different individuals groups and in some animals from different regions of the country. Based on this, this study aimed to assess the prevalence of serological and molecular makers of HEV infection and the standardization of real-time PCR for the detection and quantification of HEV viral load in HIV-infected individuals in São Paulo. Serum and plasma samples of HIV-infected patients (n=354), collected between 2007 and 2013, were included and organized in groups of co-infection (HIV/ HBV, HIV/HCV and HIV/ HBV/ HCV) and HIV mono-infection. Antibodies anti-HEV IgM and IgG were detected by ELISA (RecomWell HEV IgM/ IgG - MIKROGEN®), and in some cases confirmed by immunoblotting (RecomLine HEV IgM/ IgG - MIKROGEN®). All samples were submitted to research HEV RNA by real-time PCR. About 72% of the patients were male. The mean age of this population was 48.4 years. The anti-HEV IgM and IgG antibodies were found in 1.4% and 10.7%, respectively. Only two patients presented simultaneous anti-HEV IgM and anti- HEV IgG. There was no statistically significant difference in the presence of serological makers among the HIV infection groups. In addition, HEV RNA was detected in 10.7% of samples and six of these samples presented simultaneously a serological maker (5 anti-HEV IgG and 1 IgM). The presence of this maker was more frequent in the co-infection HIV/ HCV group. Through this work, we observed that HEV is circulating among the HIV-infected population in São Paulo, and the monitoring these patients is necessary because of the possibility progression to chronic infection and cirrhosis
92

Amélioration des services de génomiques et de surveillance du virus du syndrome reproducteur et respiratoire porcin

Lalonde, Christian 04 1900 (has links)
Le virus du syndrome reproducteur et respiratoire porcin (VSRRP) est un pathogène important, entrainant des pertes économiques de 130 millions de dollars annuellement au Canada. La surveillance est effectuée par séquençage Sanger du gène ORF5 mais nous croyons que le séquençage du génome entier (SGE) du VSRRP permettrait une meilleure surveillance épidémiologique comparé au séquençage du gène ORF5. Pour développer une méthode efficace de SGE du VSRRP, 149 échantillons (sérums, poumons, tissus, autres) d’animaux malades ou récoltés pour fin de surveillance ont été analysés. L'ARN viral a été concentré par enrichissement d'ARN à queue poly (A) et le séquençage effectué sur une plateforme Illumina. Le SGE a été efficace dans 67,11% des échantillons, réussissant dans certains échantillons de poumons et de sérums possédant une valeur de quantification (Cq) du virus par RTqPCR jusqu’à 26,50 et 34.13, respectivement. La méthodologie développée de SGE du VSRRP a été 4650 fois plus sensible que les méthodes décrites précédemment. Pour quantifier l’impact du SGE, 88 échantillons (dont le SGE a réussi) ont été utilisés pour comparer le SGE au séquençageORF5. Deux génomes de VSRRP différents ont été trouvés dans quatre échantillons différents (taux de coinfection de 4,55%). Six génomes de VSRRP (6,52% des souches) ont été classés différemment par rapport à la classification ORF5. Ainsi, le SGE du VSRRP a permis une meilleure caractérisation de 9,10% des échantillons VSRRP positifs comparé au séquençage ORF5. Donc, le SGE du VSRRP est à la fois sensible et plus précis que la classification par l’ORF5. / Porcine reproductive and respiratory syndrome virus (PRRSV) is an important pathogen, costing over 130 million dollars annually in Canada. Surveillance is done by Sanger sequencing of the ORF5 gene, but we hypothesized that whole genome sequencing (WGS) of PRRSV genome will allow a better epidemiological monitoring of PRRSV compared to ORF5 gene sequencing. To develop an efficient method of PRRSV WGS, 149 PRRSV samples (sera, lungs, pool of tissues and others) collected for surveillance or from sick animals were tested. Viral RNA was concentrated using a poly(A) tailed RNA enrichment method, and sequencing was done on an Illumina platform. WGS was successful in 67.11% of cases. WGS was successful in some tissues and lungs samples with RT-qPCR cycle quantification (Cq) values up to 26.50, and in some sera with Cq value up to 34.13. The developed WGS methodology was 4650 times more sensitive for PRRSV WGS than previously described methods. To quantify the impact of WGS, 88 successful samples for the WGS of PRRSV were used to compare efficiency of WGS and ORF5 sequencing. Two different full-length genomes of PRRSV were found in four of those samples (coinfection rate of 4.55%). Six full-length PRRSV genomes (6.52% of PRRSV strains) were found to cluster differently compared to ORF5 sequencing. WGS of PRRSV also enabled a better classification or characterisation of 9.10% of the PRRSV infected samples compared to ORF5 sequencing. Thus, WGS can be both sensitive and more accurate then ORF5 classification for the characterisation of PRRSV strains.
93

<b>Agent-Based Modeling Of </b><b>Infectious Disease Dynamics: Insights into Tuberculosis, Pediatric HIV, and Tuberculosis-HIV Coinfection</b>

Alexis Lynn Hoerter (18424443) 23 April 2024 (has links)
<p dir="ltr">Tuberculosis (TB), caused by <i>Mycobacterium tuberculosis</i> (<i>Mtb</i>), and human immunodeficiency virus-1 (HIV) are major public health concerns, individually and in combination. The status of the host immune system, previous <i>Mtb</i> infection and HIV-mediated T cell exhaustion, can have significant impacts on immune dynamics during reinfection. Individuals with asymptomatic latent TB infection (LTBI) may be protected against <i>Mtb </i>reinfection, as demonstrated by animal and <i>in vitro </i>studies. However, the underlying dynamics and protective mechanisms of LTBI are poorly understood. In HIV, long-term infection in children and associated T cell exhaustion leads to weakened immune responses to HIV reinfection. The complexity of these infections, particularly in the context of the heightened vulnerability of HIV+ individuals to TB, underscores the need for novel investigative approaches to study host-pathogen and pathogen-pathogen interactions. To this, we have developed an agent-based model (ABM) as a mechanistic computational tool to simulate the immune response to <i>Mtb </i>and HIV, separately and during coinfection. Our ABM integrates clinical and experimental data; simulates immune cell dynamics between macrophages, CD4+ and CD8+ T cells; and produces emergent granuloma-like structures – a critical response to <i>Mtb</i>. This <i>in silico</i> approach allows us to efficiently explore host-pathogen interactions and their clinical implications. By unraveling the complex interplay of immune cell activation, T cell exhaustion, and pathogen dynamics, our model offers insights that could guide the development of targeted therapies. By quantifying the multifaceted nature of these diseases and their interactions, we highlight the potential of computational approaches in understanding and treating complex diseases, individually and in combination.</p>
94

Vírus linfotrópicos de células T humanas dos tipos 1 e 2 (HTLV-1 e HTLV-2). Estudo de segmentos do genoma proviral obtidos de pacientes com HIV/Aids de São Paulo e de Londrina e região / Human T-lymphotropic virus type 1 and 2 (HTLV-1 and HTLV-2). Study on proviral genome segments obtained from patients with HIV/Aids from Sao Paulo and Londrina and vicinities.

Magri, Mariana Cavalheiro 26 September 2013 (has links)
O Brasil é considerado o país com o maior número absoluto de indivíduos infectados pelos vírus linfotrópicos de células T humanas dos tipos 1 e 2 (HTLV-1 e HTLV2), perto de 2,5 milhões; além disso, é também considerado epidêmico para o HIV e, portanto, casos de coinfecção HIV/HTLV são frequentes no país. O presente trabalho efetuou o seqüenciamento das regiões LTR, env e tax do genoma proviral do HTLV-1 e do HTLV-2 isolados das amostras de sangue de pacientes coinfectados pelo HIV-1 de Londrina e região (n=34) e de São Paulo (n=20), para realizar a caracterização molecular e determinar subtipos virais. Foram utilizadas na análise das sequências as ferramentas Sequencher 4.7, BLAST, Genotyping-NCBI, Subtyping-REGA, BioEdit 7.0.5.3, ClustalW, GenBank, PAUP 4.0.b10, Modeltest 3.7, TreeView 1.6.6 e MEGA4. As diversas análises confirmaram como subtipos prevalentes o HTLV-1a, subgrupo Transcontinental A, e o HTLV-2a (variante -2c). Foram detectadas assinaturas moleculares nos isolados do Brasil. Detectou-se o genótipo brasileiro taxA para o HTLV-1 e para o HTLV-2 a Tax longa, a qual é característica da variante HTLV-2c. Houve também a confirmação da troca de aminoácido S1909P no env dos HTLV-2. Especulou-se sobre duas entradas do HTLV-1 no Brasil e sobre a disseminação do HTLV-2c em grupos distintos quanto ao comportamento de risco e região geográfica. O estabelecimento de métodos laboratoriais otimizados para isolados brasileiros de HTLV-1 e HTLV-2 possibilitou melhor compreensão da diversidade genômica e da origem e disseminação dos HTLVs em populações coinfectadas pelo HIV no Brasil. / Brazil is considered the country with the major absolute number of individuals infected with human T-lymphotropic virus types 1 and 2 (HTLV-1 and HTLV-2), close to 2,500,000; moreover, it is also considered epidemic for HIV/Aids =and therefore HIV/HTLV coinfection is frequent in the country. This study aimed at sequencing the LTR, env and tax regions of the proviral genome of HTLV-1 and HTLV-2 isolated from blood samples obtained from patients coinfected with HIV-1 from Londrina and vicinities (n=34) and São Paulo (n=20), in order to perform the molecular characterization and viral subtyping. For sequences analysis, several bioinformatics tools were employed: Sequencher 4.7, BLAST, Genotyping-NCBI, Subtyping-REGA, BioEdit 7.0.5.3, ClustalW, GenBank, PAUP 4.0.b10, Modeltest 3.7, TreeView 1.6.6 and MEGA4. The results confirmed as prevalent the HTLV-1a subtype, the Transcontinental subgroup A, and the HTLV-2a (variant-2c). Molecular signatures characteristic of Brazilian isolates were detected: taxA Brazilian genotype in HTLV-1, and the long Tax which is characteristic of the HTLV-2c in HTLV-2. Also, it was confirmed the S1909P amino acid change in the env region of HTLV-2c. It was speculated on two entrances of HTLV-1 in Brazil, and on the spread of HTLV-2c in distinct groups related to risk factors and geographic region. The establishment and optimization of laboratory methods performed in this study allowed to get a better understanding on HTLVs genomic diversity, and to give insights on the origin and spread of HTLVs in populations coinfected with HIV in Brazil.
95

Vírus linfotrópicos de células T humanas dos tipos 1 e 2 (HTLV-1 e HTLV-2). Estudo de segmentos do genoma proviral obtidos de pacientes com HIV/Aids de São Paulo e de Londrina e região / Human T-lymphotropic virus type 1 and 2 (HTLV-1 and HTLV-2). Study on proviral genome segments obtained from patients with HIV/Aids from Sao Paulo and Londrina and vicinities.

Mariana Cavalheiro Magri 26 September 2013 (has links)
O Brasil é considerado o país com o maior número absoluto de indivíduos infectados pelos vírus linfotrópicos de células T humanas dos tipos 1 e 2 (HTLV-1 e HTLV2), perto de 2,5 milhões; além disso, é também considerado epidêmico para o HIV e, portanto, casos de coinfecção HIV/HTLV são frequentes no país. O presente trabalho efetuou o seqüenciamento das regiões LTR, env e tax do genoma proviral do HTLV-1 e do HTLV-2 isolados das amostras de sangue de pacientes coinfectados pelo HIV-1 de Londrina e região (n=34) e de São Paulo (n=20), para realizar a caracterização molecular e determinar subtipos virais. Foram utilizadas na análise das sequências as ferramentas Sequencher 4.7, BLAST, Genotyping-NCBI, Subtyping-REGA, BioEdit 7.0.5.3, ClustalW, GenBank, PAUP 4.0.b10, Modeltest 3.7, TreeView 1.6.6 e MEGA4. As diversas análises confirmaram como subtipos prevalentes o HTLV-1a, subgrupo Transcontinental A, e o HTLV-2a (variante -2c). Foram detectadas assinaturas moleculares nos isolados do Brasil. Detectou-se o genótipo brasileiro taxA para o HTLV-1 e para o HTLV-2 a Tax longa, a qual é característica da variante HTLV-2c. Houve também a confirmação da troca de aminoácido S1909P no env dos HTLV-2. Especulou-se sobre duas entradas do HTLV-1 no Brasil e sobre a disseminação do HTLV-2c em grupos distintos quanto ao comportamento de risco e região geográfica. O estabelecimento de métodos laboratoriais otimizados para isolados brasileiros de HTLV-1 e HTLV-2 possibilitou melhor compreensão da diversidade genômica e da origem e disseminação dos HTLVs em populações coinfectadas pelo HIV no Brasil. / Brazil is considered the country with the major absolute number of individuals infected with human T-lymphotropic virus types 1 and 2 (HTLV-1 and HTLV-2), close to 2,500,000; moreover, it is also considered epidemic for HIV/Aids =and therefore HIV/HTLV coinfection is frequent in the country. This study aimed at sequencing the LTR, env and tax regions of the proviral genome of HTLV-1 and HTLV-2 isolated from blood samples obtained from patients coinfected with HIV-1 from Londrina and vicinities (n=34) and São Paulo (n=20), in order to perform the molecular characterization and viral subtyping. For sequences analysis, several bioinformatics tools were employed: Sequencher 4.7, BLAST, Genotyping-NCBI, Subtyping-REGA, BioEdit 7.0.5.3, ClustalW, GenBank, PAUP 4.0.b10, Modeltest 3.7, TreeView 1.6.6 and MEGA4. The results confirmed as prevalent the HTLV-1a subtype, the Transcontinental subgroup A, and the HTLV-2a (variant-2c). Molecular signatures characteristic of Brazilian isolates were detected: taxA Brazilian genotype in HTLV-1, and the long Tax which is characteristic of the HTLV-2c in HTLV-2. Also, it was confirmed the S1909P amino acid change in the env region of HTLV-2c. It was speculated on two entrances of HTLV-1 in Brazil, and on the spread of HTLV-2c in distinct groups related to risk factors and geographic region. The establishment and optimization of laboratory methods performed in this study allowed to get a better understanding on HTLVs genomic diversity, and to give insights on the origin and spread of HTLVs in populations coinfected with HIV in Brazil.
96

Interacció VHC-hoste: Estudi genètic i clínic en pacients coinfectats amb VHC-VIH

Matas Crespí, Marina 14 January 2013 (has links)
L’Organització Mundial de la Salut (OMS) estima que fins a un 3% de la població mundial ha estat infectada pel virus de l’hepatitis C i és la causa més important d’hepatitis crònica, cirrosi i de malaltia hepàtica terminal, que finalment acaba conduint a un transplantament de fetge. La relació entre la variabilitat en la seqüència del virus de l’hepatitis C i el desenvolupament de la malaltia hepàtica és de tipus multifactorial. La infecció crònica causa fibrosi hepàtica, fet que es veu accelerat per mecanismes desconeguts en el cas de pacients coinfectats amb VIH. La progressió de la malaltia produïda pel VHC en pacients coinfectats, està influenciada no només per factors demogràfics, epidemiològics o pels antecedents clínics dels pacients, si no també per diferències genètiques entre els diferents virus i els hostes.

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