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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.
121

Associação de polimorfismos em um único nucleotídeo nos genes GPX4,CYBB, CYBA, CAT e SLC2A2 e a susceptibilidade à doença renal crônica em coortes brasileira e francesas de portadores de diabetes mellitus tipo 1 / Association of single nucleotide polymorphisms in the genes GPX4, CYBB, CYBA, CAT e SLC2A2 and the susceptibility to chronic kidney disease in Brazilian and French cohorts of type 1 diabetes mellitus patients

Thiago Andrade Patente 18 July 2014 (has links)
A nefropatia diabética (ND) é uma das principais causas de nefropatia crônica, o que torna o diabetes mellitus (DM) responsável por 44% da prevalência de doença renal crônica (DRC) no mundo. O papel do estresse oxidativo na patogênese da ND está bem estabelecido e genes pertencentes a vias pró- e antioxidantes são possíveis candidatos a conferirem susceptibilidade genética a essa e a outras complicações crônicas. Além do estresse oxidativo, o transporte intracelular de glicose, mediado por transportadores específicos, também parece exercer influência sobre a ND e outras complicações. O objetivo deste trabalho foi avaliar a associação entre ND e alguns polimorfismos de um único nucleotídeo (SNPs) em genes que codificam proteínas transportadoras de glicose (GLUT2 [SLC2A2]), proteínas pró-oxidantes (p22phox [CYBA] e NOX-2 [CYBB]) e proteínas antioxidantes (glutationa peroxidase-4 [GPX4] e catalase [CAT]) em uma coorte brasileira (n=453; 45,8% de pacientes com ND) e três coortes francesas (SURGENE [n=340; 17,7% de pacientes com ND na fase basal], GENEDIAB [n=313; 66,7% de pacientes com ND] e GENESIS [n=636; 49,7% de pacientes com ND]) de pacientes portadores de DM tipo 1. Os SNPs foram genotipados com o uso da técnica de reação em cadeia da polimerase (PCR) em tempo real e os resultados expressos em odds ratio (OR) ou hazard ratio (HR), com seus respectivos intervalos de confiança (IC), determinados em modelos ajustados de regressão logística politômica ou regressão de risco proporcional de Cox, respectivamente. A razão albumina/creatinina urinária (ACR) ou a taxa de excreção urinária de albumina (EUA) foram utilizadas para definir os estágios de ND e os pacientes foram classificados de acordo com a presença ou ausência de ND incipiente (ACR 30 - 300 mg/g de creatinina ou EUA 20 - 200 ?g/min ou 20 - 200 mg/L) e creatinina plasmática <1,7 mg/dL), ND estabilizada (ACR >300 mg/g de creatinina ou EUA > 200 ug/min ou > 200 mg/L e creatinina plasmática < 1,7 mg/dL ) ou ND avançada (ACR > 300 mg/g de creatinina ou EUA > 200 ug/min ou > 200 mg/L e creatinina plasmática > 1,7 mg/dL ou qualquer terapia de reposição renal) e também foram avaliadas associações dos SNPs com a taxa de filtração glomerular estimada (TFGe). O alelo raro A do SNP rs6610650 no gene CYBB foi associado com valores baixos de TFGe em mulheres na coorte brasileira e com a prevalência de ND estabilizada/avançada em mulheres da coorte francesa (OR 1,75; IC 95% 1,11 - 2,78; p=0,016). O alelo raro T do SNP rs713041 no gene GPX4 foi inversamente associado com a prevalência de ND estabilizada/avançada em homens na coorte brasileira (OR 0,30, IC95% 0,13 - 0,68, p=0,004) e com valores elevados de TFGe em homens na coorte francesa. O alelo raro A do SNP rs7947841 no gene CAT foi associado com a prevalência de ND incipiente (OR 2,79; IC95% 1,21 - 6,24; p=0,01) e ND estabilizada/avançada (OR 5,72; IC95% 1,62 - 22,03; p=0,007), bem como com a incidência de eventos renais, definidos como novos casos de microalbuminúria ou progressão para um estágio mais grave de ND durante o seguimento de estudo, na coorte SURGENE (HR 1,82; IC95% 1,13 - 2,81; p=0,01). O mesmo alelo de risco associou-se com a prevalência de ND incipiente (OR 3,13; IC95% 1,42 - 7,24; p=0,004) e com a incidência de insuficiência renal crônica terminal (IRCT) na coorte GENEDIAB (HR 2,11; IC95% 1,23 - 3,60; p=0,008) e com a prevalência de ND incipiente (OR 2,16; IC95% 1,14 - 4,10, p=0,02) e ND estabilizada/avançada (OR 2,71; IC95% 1,38 - 5,42; p=0,004) na coorte brasileira. O alelo raro T do SNP rs9932581 no gene CYBA foi inversamente associado com a prevalência de ND estabilizada/avançada (OR 0,60; IC95% 0,46 - 0,78; p=0,0001) e com valores mais baixos de TFGe nos pacientes de descendência europeia da coorte GENESIS/GENEDIAB. Este mesmo alelo foi associado com a incidência de eventos renais e de IRCT nas coortes SURGENE (HR 0,63; IC95% 0,46 - 0,86; p=0,003) e GENESIS/GENEDIAB (HR 0,51; IC95% 0,31 - 0,78; p=0,002), respectivamente. Entretanto estes resultados não foram replicados na coorte brasileira. O alelo raro T do SNP rs11924032 no gene SLC2A2 foi inversamente associado com a perda da TFGe ao logo do tempo (0,02%/ano vs 2,18%/ano para os pacientes portadores do genótipo GG; p=0,005), na coorte SURGENE. Este mesmo alelo foi inversamente associado com a incidência de IRCT nas coortes GENESIS/GENEDIAB (HR 0,53; IC95% 0,29 - 0,89; p=0,01). Os resultados observados para o gene SLC2A2 não forneceram fortes indícios para afirmarmos que este gene exerça um papel relevante no desenvolvimento da ND nos pacientes com DM tipo 1 nas coortes francesas estudadas. Em contrapartida, os SNPs nos genes que codificam as proteínas pró-oxidantes CYBA e CYBB e as proteínas antioxidantes GPX-4 e CAT foram capazes de modular o risco para doença renal em pacientes portadores de DM tipo 1, sendo que os SNPs presentes nos genes CYBB, GPX4 e CAT tiveram seus resultados replicados em coortes independentes, o que corrobora a importância destes genes e, consequentemente, do estresse oxidativo, na patogênese da ND / Diabetic nephropathy (DN) is a major cause of chronic nephropathy, with diabetes mellitus (DM) accounting for 44% of the prevalence of chronic kidney disease (CKD) in the world. The role of oxidative stress in the pathogenesis of DN is well established and genes belonging to pro- and antioxidant pathways are possible candidates to confer genetic susceptibility to this and other chronic complications. Besides oxidative stress, intracellular glucose transport mediated by specific transporters, also appears to influence DN and other complications. The aim of this study was to evaluate the association between DN and some single nucleotide polymorphisms (SNPs) present in genes encoding glucose transport proteins (GLUT2 [SLC2A2]), pro- (p22phox [CYBA] and NOX-2 [CYBB]) and antioxidants (glutathione peroxidase-4 [GPX4] and catalase [CAT]) proteins, in a Brazilian cohort [n= 453; 45.8% f patients with DN], and three French cohorts (SURGENE [n=340; 17.7% of patients with DN at baseline], GENEDIAB [n=313; 66.7% of patients with DN], and GENESIS [n=636; 49.7% of patients with DN]) of patients with type 1 DM. The SNPs were genotyped using the technique of real time polymerase chain reaction (PCR) and results expressed as odds ratio (OR) and hazard ratio (HR), with their respectively 95% confidence intervals (CI), determined by adjusted models of polytomic logistic regression and Cox proportional hazard regression, respectively. The albumin/creatinine ratio (ACR) or the urinary albumin excretion (UAE) rate were used to define the DN stages and the patients were classified according to the presence or absence of incipient DN (ACR 30 - 300 mg/g of creatinine or UAE 20 - 200 ug/min or 20 - 200 mg/L) and plasmatic creatinine < 1,7 mg/dL), established DN (ACR > 300 mg/g of creatinine or EUA > 200 ug/min or > 200 mg/L and plasmatic creatinine <1,7 mg/dL) or advanced DN (ACR >300 mg/g of creatinine or UAE > 200 ug/min or > 200 mg/L and plasmatic creatinine > 1,7 mg/dL or any renal replacement therapy). Associations for the estimated glomerular filtration rate (eGFR) were also evaluated. The rare allele A of the SNP rs6610650 in CYBB gene was associated with low values of eGFR in women in the Brazilian cohort and with the prevalence of established/advanced DN in women in the French cohort (OR 1.75, 95%CI 1.11 - 2.78, p=0.016). The rare allele T of the SNP rs713041 in GPX4 gene was inversely associated with the prevalence of established/advanced DN in men in the Brazilian cohort (OR 0.30, 95%CI 0.13 - 0.68, p=0.004) and with higher values of eGFR in men in the French cohort. The rare allele A of the SNP rs7947841 in CAT gene was associated with the prevalence of incipient DN (OR 2.79, 95%CI 1.21 - 6.24, p=0.01) and established/advanced DN (OR 5.72; 95%CI 1.62 - 22.03, p=0.007) as well as the incidence of renal events, defined as new cases of microalbuminuria or progression to a more severe stage during the follow-up study, in SURGENE cohort (HR 1.82, 95%CI 1.13 - 2.81, p=0.01). The same risk allele was associated with the prevalence of incipient DN (OR 3.13, 95%CI 1.42 - 7.24, p=0.004), the incidence of end-stage renal disease (ESRD) in the cohort GENEDIAB (HR 2.11, 95%CI 1.23 - 3.60, p=0.008) and with the prevalence of incipient DN (OR 2.16, 95%CI 1.14 - 4.10, p=0.02) and established/advanced DN (OR 2.71, 95%CI 1.38 - 5.42, p=0.004) in the Brazilian cohort. The rare T allele of the SNP rs9932581 in CYBA gene was inversely associated with the prevalence of established/advanced DN (OR: 0.60, 95%CI: 0.46 - .78, p=0.0001) and associated with lower values of eGFR in patients of GENESIS/GENEDIAB cohort. The same allele was inversely associated with the incidence of renal events and ESRD in SURGENE (HR 0.63, 95%CI 0.46 - 0.86, p=0.003) and GENESIS/GENEDIAB (HR 0.51, 95%CI 0.31 - 0.78, p=0.002) cohorts. However, these results were not replicated in the Brazilian cohort. The rare T allele of the SNP rs11924032 in SLC2A2 gene was inversely associated with the loss of eGFR during the follow-up (0.02%/year vs. 2.18%/year for patients with the GG genotype, p=0.005) in the SURGENE cohort. The same allele was inversely associated with the incidence of ESRD in the GENESIS/GENEDIAB cohorts (HR 0.53, 95%CI 0.29 - 0.89, p=0.01). The results observed for the SLC2A2 gene, in this study, did not provide strong evidence to state that this gene exerts a relevant role in the development of DN in patients with type 1 DM in the studied cohorts. However, SNPs in genes encoding the pro-oxidant proteins CYBA and CYBB, and the antioxidants proteins GPX-4 and CAT were able to modulate the risk of renal disease in patients with type 1 DM. The studied SNPs in CYBB, GPX4 and CAT genes had their results replicated in independent cohorts, which confirms the importance of these genes and, hence, of the oxidative stress in the pathogenesis of DN
122

Polimorfismos de enzimas de fase 1 e 2 do metabolismo de drogas em pacientes portadores de linfoma difuso de grandes células B / Polymorphisms of phase 1 and 2 enzymes of drugs metabolism in patients with diffuse large B cell lymphoma

Pamela Oliveira de Souza 27 June 2011 (has links)
Para avaliar a influência dos polimorfismos de nucleotídeo único (SNPs) do CYP2B6, CYP3A5, GSTM1, GSTP1, GSTT1, PON1, NQO1 e MDR1 na resposta ao tratamento com R-CHOP e CHOP, 82 pacientes com Linfoma Difuso de Grandes Células B, sem evidências de infecção por HIV, foram selecionados nesse estudo. Amostras de sangue periférico foram coletadas para extração de DNA. Os SNPs foram analisados por PCR-RFLP. Em relação aos pacientes que apresentaram resposta completa (RC) ao tratamento (70%), 51% foram tratados com R-CHOP. Sobre o tratamento, 50% dos pacientes com RC apresentaram classificação de ECOG 0-1 (p=0,0193) e a maioria desses pacientes (41%) não apresentaram envolvimento extranodal (p=0,0377). Não houve associação entre os SNPs do CYP2B6, CYP3A5, GSTT1, NQO1 e MDR1 (C3435T) e as variáveis estudadas. Apenas CYP3A5 (sexo p=0,0519), GSTM1 (idade p=0,016; tratamento p=0,0372), GSTP1 (envolvimento extranodal p=0,0307), PON1 (sintomas B p=0,0201; Bulky p=0,0148) e MDR1 C1236T (sexo p=0,0316) mostraram associação. Em relação à sobrevida global, apenas tratamento (p=0,0129), IPI (p=0,000342), idade (p=0,0155), estadiamento (p=0,00281) e ECOG (p=0,00869) apresentaram resultados significantes. Quanto à sobrevida livre de doença (SLD), apenas idade (p=0,0292), estadiamento (p=0,0402) e ECOG (p=0,0142) apresentaram resultados significantes / To evaluated the influence of single nucleotide polymorphisms (SNPs) of CYP2B6, CYP3A5, GSTM1, GSTP1, GSTT1, PON1, NQO1 and MDR1 in the treatment response with R-CHOP and CHOP, 82 patients with Diffuse Large B-cell Lymphoma, without evidence of HIV infection, were enrolled in this study. Peripheral blood samples were collected for DNA extraction. The SNPs were analyzed by PCR-RFLP. In relation the patients that showed complete response (CR) to the treatment (70%), 51% were treated with R-CHOP. About the treatment, 50% of the patients with CR showed ECOG classification of 0-1 and the most of these patients (41%) did not showed extranodal involvement (p=0,0377). There was no association between CYP2B6, CYP3A5, GSTT1, NQO1 and MDR1 (C3435T) SNPs and the variables studied. Only CYP3A5 (gender p=0,0519), GSTM1 (age p=0,016; treatment p=0,0372), GSTP1 (extranodal involvement p=0,0307), PON1 (B symptoms p=0,0201; Bulky p=0,0148) e MDR1 C1236T (gender p=0,0316) showed association. In relation to overall survival, only treatment (p=0,0129), IPI (p=0,000342), age (p=0,0155), stadiament (p=0,00281) and ECOG (p=0,00869) showed significant results. To disease-free survival, only age (p=0,0292), stadiament (p=0,0402) e ECOG (p=0,0142) showed significant results
123

Um método para seleção de atributos em dados genômicos

Oliveira, Fabrízzio Condé de 26 November 2015 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-05T18:05:07Z No. of bitstreams: 1 fabrizziocondedeoliveira.pdf: 6115188 bytes, checksum: 9810536208119e2012e4ee9015470c3e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-06-07T15:41:26Z (GMT) No. of bitstreams: 1 fabrizziocondedeoliveira.pdf: 6115188 bytes, checksum: 9810536208119e2012e4ee9015470c3e (MD5) / Made available in DSpace on 2016-06-07T15:41:26Z (GMT). No. of bitstreams: 1 fabrizziocondedeoliveira.pdf: 6115188 bytes, checksum: 9810536208119e2012e4ee9015470c3e (MD5) Previous issue date: 2015-11-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Estudos de associação em escala genômica buscam encontrar marcadores moleculares do tipo SNP que estão associados direta ou indiretamente a um fenótipo em questão tais como, uma ou mais características do indivíduo ou, até mesmo, uma doença. O SNP pode ser a própria mutação causal ou pode estar correlacionado com a mesma por serem herdados juntos. Para identi car a região causadora ou promotora do fenótipo, a qual não é conhecida a priori, milhares ou milhões de SNPs são genotipados em amostras compostas de centenas ou milhares de indivíduos. Com isso, surge o desa o de selecionar os SNPs mais informativos no conjunto de dados genotípico, onde o número de atributos é, geralmente, muito superior ao número de indivíduos, com a possibilidade de que existam atributos altamente correlacionados e, ainda, podendo haver interações entre pares, trios ou combinações de SNPs de quaisquer ordens. Os métodos mais usados em estudos de associação em escala genômica utilizam o valor-p de cada SNP em testes estatísticos de hipóteses, baseados em regressão para fenótipos contínuos e baseados nos testes qui-quadrado ou similares em classi cação para fenótipos discretos, como ltro para selecionar os SNPs mais signi cativos. Entretanto, essa classe de métodos captura somente SNPs com efeitos aditivos, pois a relação adotada é linear. Na tentativa de superar as limitações de procedimentos já estabelecidos, este trabalho propõe um novo método de seleção de SNPs baseado em técnicas de Aprendizado de Máquina e Inteligência Computacional denominado SNP Markers Selector (SMS). O modelo é construído a partir de uma abordagem que divide o problema de seleção de SNPs em três fases distintas: a primeira relacionada à análise de relevância dos marcadores, a segunda responsável pela de nição do conjunto de marcadores relevantes que serão considerados por meio de uma estratégia de corte com base em um limite de relevância dos marcadores e, nalmente, uma fase para o re namento do processo de corte, geralmente para diminuir marcadores falsos-positivos. No SMS, essas três etapas, foram implementadas utilizando-se Florestas Aleatórias, Máquina de Vetores Suporte e Algoritmos Genéticos respectivamente. O SMS objetiva a criação de um uxo de trabalho que maximize o potencial de seleção do modelo através de etapas complementares. Assim, espera-se aumentar o potencial do SMS capturar efeitos aditivos e/ou não-aditivos com interação moderada entre pares e trios de SNPs, ou até mesmo, interações de ordens superiores com efeitos que sejam minimamente detectáveis. O SMS pode ser aplicado tanto em problemas de regressão (fenótipo contínuo) quanto de classi cação (fenótipo discreto). Experimentos numéricos foram realizados para avaliação do potencial da estratégia apresentada, com o método sendo aplicado em sete conjuntos de dados simulados e em uma base de dados real, onde a capacidade de produção de leite predita de vacas leiteiras foi medida como fenótipo contínuo. Além disso, o método proposto foi comparado com os métodos baseados no valor-p e com o Lasso Bayesiano apresentando, de forma geral, melhores resultados do ponto de vista de SNPs verdadeiros-positivos nos dados simulados com efeitos aditivos juntamente com interações entre pares e trios de SNPs. No conjunto de dados reais, baseado em 56.947 SNPs e um único fenótipo relativo à produção de leite, o método identi cou 245 QTLs associados à produção e à composição do leite e 90 genes candidatos associados à mastite, à produção e à composição do leite, sendo esses QTLs e genes identi cados por estudos anteriores utilizando outros métodos de seleção. Assim, o método demonstrou ser competitivo frente aos métodos utilizados para comparação em cenários complexos, com dados simulados ou reais, o que indica seu potencial para estudos de associação em escala genômica em humanos, animais e vegetais. / Genome-wide association studies have as main objective to discovery SNP type molecular markers associated directly or indirectly to a speci c phenotype related to one or more characteristics of an individual or even a disease. The SNP could be the causative mutation itself or correlated with the causative mutation due to common inheritance. Aiming to identify the causal or promoter region of the phenotype, which is unknown a priori, thousands or millions of SNPs are genotyped in samples composed of hundreds or thousands of individuals. Therefore, emerges the necessity to confront a challenge of selecting the most informative SNPs in genotype data set where the number of attributes are, usually, much higher than the number of individuals. Besides, the possibility of highly correlated attributes should be considered, as well as interactions between pairs, trios or combinations of high order SNPs. The most usual methods applied on genomewide association studies adopt the p-value of each SNP as a lter to select the SNPs most signi cant. For continuous phenotypes the statistical regression-based hypothesis test is used and the Chi-Square test or similar for classi cation of discrete phenotypes. However, this class of methods capture only SNPs with additive e ects, due to the linear relationship considered. In an attempt to overcome the limitations of established procedures, this work proposes a new SNPs selection method, named SNP Markers Selector (SMS), based on Machine Learning and Computational Intelligence strategies. The model is built considering an approach which divides the SNPs selection problem in three distinct phases: the rst related to the evaluation of the markers relevance, a second responsible for the de nition of the set of the relevant markers that will be considered by means of a cut strategy based on a threshold of markers relevance and, nally, a phase for the re nement of the cut process, usually to diminish false-positive markers. In the SMS, these three steps were implemented using Random Forests, Support Vector Machine and Genetic Algorithms, respectively. The SMS intends to create a work ow that maximizes the SNPs selection potential of the model due to the adoption of steps considered complementary. In this way, there is an increasing expectation on the performance of the SMS to capture additive e ects, moderate non-additive interaction between pairs and trios of SNPs, or even, higher order interactions with minimally detectable e ects. The SMS can be applied both in regression problems (continuous phenotype) as in classi cation problems (discrete phenotype). Numerical experiments were performed to evaluate the potential of the strategy, with the method being applied in seven sets of simulated data and in a real data set, where milk production capacity predicated of dairy cows was measured as continuous phenotype. Besides, the comparison of the proposed method with methods based on p-value and Lasso Bayesian technique indicate, in general, competitive results from the point of view of true-positive SNPs using simulated data set with additive e ects in conjunction with interactions of pairs and trios of SNPs. In the real data, based on 56,947 SNPs and a single phenotype of milk production, the method identi ed 245 QTLs associated with milk production and composition and 90 candidate genes associated with mastitis, milk production and composition, standing out that these QTLs and genes were identi ed by previous studies using other selection methods. Thus, the experiments showed the potential of the method in relation to other strategies when complex scenarios with simulated or real data are adopted, indicating that the work ow developed to guide the construction of the method should be considered for genome-wide asociation studies in humans, animals and plants.
124

Characterization of the membrane transporter OATP1A2 activity towards different classes of drugs

Lu, Jennifer 12 1900 (has links)
Les transporteurs membranaires sont des éléments importants dans le devenir, l’efficacité, et la toxicité du médicament. Ils influencent la pharmacocinétique et la pharmacodynamie de ces derniers. Plusieurs interactions médicamenteuses observées cliniquement sont attribuables à la fois aux enzymes responsables du métabolisme des médicaments et aux transporteurs membranaires. Il est connu qu’une variabilité existe entre différents individus dans la réponse à un médicament et les polymorphismes génétiques retrouvés dans les gènes codant pour les transporteurs membranaires peuvent partiellement expliquer cette variabilité. OATP1A2 est un transporteur membranaire exprimé sur des organes importants, comme le cerveau et le rein. Plusieurs médicaments utilisés en clinique sont des substrats d’OATP1A2 et l’expression localisée de ce transporteur suggère un rôle important dans le devenir du médicament. Donc, mon projet de doctorat consistait à caractériser l’activité d’OATP1A2 en relation avec ses substrats et inhibiteurs, et de plus, à évaluer l’impact de différents variants génétiques d’OATP1A2 sur leur transport. Dans le premier article, la rosuvastatine a été utilisée comme substrat-type pour étudier le transport d’OATP1A2. Les expériences ont été menées en introduisant la rosuvastatine en compétition avec différent β-bloqueurs, une classe de médicaments rapportée dans la littérature comme substrats d’OATP1A2. Parmi les β-bloqueurs évalués, le carvédilol était l’inhibiteur le plus puissant. Dans la deuxième partie de l’étude, des médicaments ayant une structure similaire au carvédilol, tels que les antidépresseurs tricycliques, ont été évalués quant à leur potentiel d’inhibition sur OATP1A2. Une relation structure-activité a été définie à l’aide de ces données. Nous avons démontré que des composés tricycliques avec une courte chaîne aliphatique pouvaient inhiber OATP1A2. Dans le deuxième article, OATP1A2 a été étudié en considérant son expression et son rôle au sein de la barrière hémato-encéphalique (BHE). Des études précédentes ont démontré qu’OATP1A2 est exprimé sur la membrane luminale des cellules endothéliales formant la BHE. Nos données démontrent que les triptans, une classe de médicaments couramment utilisées pour traiter la crise migraineuse, sont des substrats d’OATP1A2 et que les composés tricycliques identifiés comme inhibiteurs d’OATP1A2 dans nos études précédentes peuvent inhiber le transport des triptans par OATP1A2. Ces résultats sont importants puisque: 1) il a été suggéré que les triptans peuvent agir au niveau du système nerveux central en se liant aux récepteurs trouvés sur les neurones centraux; 2) comme les triptans sont des molécules hydrophiles, un mécanisme de transport facilité est nécessaire pour qu’ils pénètrent la BHE et OATP1A2 pourrait être l’élément clé; 3) l’inhibition d’OATP1A2 par les composés tricycliques pourrait limiter l’accès des triptans à leur site d’action. Le troisième article caractérise l’activité associée à deux variants génétiques d’OATP1A2 (OATP1A2*2 et *3). Leur capacité à transporter les triptans et leur potentiel d’inhibition par les médicaments tricycliques ont été évalués. Des résultats supplémentaires caractérisant OATP1A2, mais sans liens directs avec les trois articles, seront présentés en annexe. Dans l’ensemble, les résultats présentés dans cette thèse servent à caractériser le transporteur membranaire OATP1A2 en relation avec ses substrats et inhibiteurs, et en fonction de ses variants génétiques. / Drug transporters are important determinants in drug disposition, efficacy, and toxicity. They influence the pharmacokinetics and pharmacodynamics of drugs. Several clinically-observed drug-drug interactions are mediated through drug metabolizing enzymes and drug transporters. It is well known that there is an interindividual variability in the response to medications and polymorphisms found in genes encoding for drug transporters partially account for it. OATP1A2 is a membrane drug transporter expressed on important organs, such as the brain and the kidney. A wide spectrum of drugs used in the clinic are substrates of OATP1A2. Its localisation suggests an essential role in drug disposition. Thus, my PhD project consisted of characterizing the activity of OATP1A2 in regards to its substrates, inhibitors, and different protein variants due to genetic polymorphisms. In the first article, rosuvastatin was used as the probe substrate to study OATP1A2 transport activity. Experiments were conducted by putting rosuvastatin in competition with different β-blockers, a class of drugs known in the literature to be transported by OATP1A2. One of the drugs evaluated, carvedilol, inhibited OATP1A2 with much more potency than the others. In the second part of the study, drugs with a structure similar to carvedilol, such as tricyclic antidepressants, were tested for their potential to inhibit OATP1A2. A structure-activity relationship was defined using the data. It was demonstrated that drugs composed of a tricyclic ring with a short aliphatic amine chain were potent OATP1A2 inhibitors. In the second article presented, OATP1A2 was studied in the context of its localization at the blood-brain barrier (BBB). OATP1A2 expression at the luminal membrane of the endothelial cells making up the BBB was demonstrated in the literature. Our article showed that triptans, a class of commonly used anti-migraine drugs, were OATP1A2 substrates. The tricyclic drugs previously evaluated were shown to potently inhibit triptan transport through OATP1A2. These findings are important for three reasons: 1) it has been postulated that triptans may act at the central nervous system by binding to receptors found on central neurons; 2) as triptans are hydrophilic molecules, a facilitated transport mechanism is required for them to penetrate the BBB and OATP1A2 may be the key player; and 3) the inhibition of OATP1A2 by the tricyclic drugs may limit the entrance of triptans to their site of action. The third article characterized the transport activity of two OATP1A2 protein variants (OATP1A2*2 and *3). Their capacities to transport triptans and their potential of being inhibited by tricyclic drugs were evaluated. Additional data characterizing OATP1A2 but considered out of the scope of the three articles will be presented in appendices. In overall, the central theme of this thesis looks into the characterization of the OATP1A2 membrane drug transporter in regards to its substrates, inhibitors, and proteins variants.
125

Effets de la reproduction partiellement asexuée sur la dynamique des fréquences génotypiques en populations majoritairement diploïdes / Effects of partial asexuality on the dynamics of genotype frequencies in dominantly diploid populations

Reichel, Katja 10 December 2015 (has links)
Les systèmes reproducteurs déterminent comment le matériel génétique est transmis d’une génération à la suivante […]. Les espèces qui combinent de la reproduction sexuée et asexuée/clonale sont très répandues [… mais] l’effet de leur système reproducteur sur leur évolution reste énigmatique et discuté.L’objectif de cette thèse est de modéliser la dynamique des fréquences génotypiques d’une population avec une combinaison de reproduction sexuée et/ou clonale dans des cycles de vie principalement diploïdes [. … Un] modèle du type chaine de Markov avec temps et états discrets sert de base mathématique pour décrire [leurs] changements […] au cours du temps.Les résultats montrent que la reproduction partiellement asexuée peut en effet modifier la dynamique de la diversité génomique par rapport à une reproduction strictement sexuée ou strictement asexuée. […] L’histoire démographique a un rôle important pour les organismes partiellement clonaux et doit être prise en compte dans toute analyse […].Cette thèse fait des recommandations pour la collecte des données et une hypothèse de base pour l’interprétation des données de génétique/génomique […]. Ces résultats ont des retombées dans plusieurs domaines, allant de la recherche fondamentale […] à des applications en agriculture […], pêche […] et protection de la nature […]. / Reproductive systems determine how genetic material is passed from one generation to the next, making them an important factor for evolution. Organisms that combine sexual and asexual/clonal reproduction are very widespread [… yet] the effects of their reproductive system on their evolution are still controversial and poorly understood.The aim of this thesis was to model the dynamics of genotype frequencies under combined sexual/clonal reproduction in dominantly diploid life cycles [. … A] state and time discrete Markov chain model served as the mathematical basis to describe [their] changes […] through time.The results demonstrate that partial clonality may indeed change the dynamics of genomic diversity compared to either exclusively sexual or exclusively clonal populations. […] Time has a crucial role in partially clonal populations and needs to be taken into account in any analysis of their genomic diversity.This thesis provides recommendations for data collection and a null hypothesis for the interpretation of population genetic/genomic data […]. Moreover, it includes new methods for the analysis of genotype-based population genetic Markov chain models. These results have a high potential relevance in several areas, ranging from basic research […] to applications in agriculture […], fisheries […] and nature conservation […].
126

Functional Analysis of the TRIB1 Locus in Coronary Artery Disease

Douvris, Adrianna January 2011 (has links)
The TRIB1 locus (8q24.13) is a novel locus associated with plasma TGs and CAD risk. Trib1 is a regulator of MAPK activity, and has been shown to regulate hepatic lipogenesis and VLDL production in mice. However, the functional relationship between common SNPs at the TRIB1 locus and plasma lipid traits is unknown; TRIB1 has not been identified as an eQTL. This cluster of SNPs falls within an intergenic region 25kb to 50kb downstream of the TRIB1 coding region. By phylogenetic footprinting analysis and DNA genotyping, we identified an evolutionarily conserved region (CNS1) within the risk locus that harbours two common SNPs in tight LD with GWAS risk SNPs and significantly associated with CAD. We investigated the regulatory function of CNS1 by luciferase reporter assays in HepG2 cells and demonstrate that this region has promoter activity. In addition, the rs2001844 risk allele significantly reduces luciferase activity, suggesting that altered expression of the EST-based gene may be associated with plasma TGs. We identified an EST within the risk locus directly downstream of CNS1. We performed 5'/3' RACE using HepG2 RNA, identified multiple variants of this EST-based gene, and confirmed its transcription start site within CNS1. We hypothesize that this EST is a long noncoding RNA due to low abundance, poor conservation, and absence of significant ORF. Over-expression of a short variant implicates its function in the regulation of target gene transcription, although the mechanism of action remains unknown. We conclude that the risk locus at 8q24.13 harbours a novel EST-based gene that may explain the relationship between GWAS SNPs at this locus and plasma lipid traits.
127

Évaluation neurobiologique des souris spontanément hypertendues : Du vieillissement à la génomique comparative

Thifault, Stéphane 12 1900 (has links)
Le but de cette thèse est premièrement d’évaluer l’effet du vieillissement sur les fonctions psychomotrices des souches de souris sélectionnées génétiquement en fonction de leur tension artérielle (TA); deuxièmement, de localiser les déterminants génétiques des phénotypes psychophysiologiques à partir de souches recombinantes congéniques (RCS). Ces travaux ont mené à la publication de 4 articles. Le premier article décrit l’évaluation des fonctions psychomotrices des souches avec une tension artérielle élevée (HBP), basse (LBP) et normale (NBP). La performance aux épreuves d’exploration, d’habiletés motrices et d’apprentissage spatial, a été mesurée sur deux cohortes âgées respectivement de 12 mois et de trois mois. Indépendamment de l’âge, les HBPs sont hyperactives dans l’open-field (OF), mais pas dans le test d’exploration de trous. Inversement, les LBP explorent moins d’espaces que les NBP et, à trois mois seulement, sont hypoactives dans l’OF. Par ailleurs, les HBPs et les LBP présentent des déficits précoces de coordination motrice et des fonctions visuo-motrices. Le second article concerne l’évaluation longitudinale de la coordination motrice, de l’anxiété et de l’apprentissage spatial des souches HBP, LBP et NBP, à l’âge de deux mois et de 12 mois. Le vieillissement accentue l’hyperactivité des HBPs dans l’OF. Par contre, l’hypoactivité des souris LBP est détectable seulement à l’âge de deux mois. Indépendamment de l’âge, les souris HBP et LBP montrent une perception réduite du danger dans l’épreuve d’anxiété et des dysfonctions visuo-motrices au labyrinthe aquatique. Enfin, des déficits précoces de coordination motrice se manifestent seulement chez les HBPs. Il reste à déterminer si les déficits observés sont liés à des déterminants génétiques indépendants ou secondaires aux altérations de la tension artérielle. Le troisième article présente la comparaison entre les souches consanguines A/J et C57Bl/6J (B6) aux épreuves de l’OF, de la planche à trous, du labyrinthe aquatique et du cintre (coordination motrice). Les B6 explore d’avantage l’OF et la planche à trous. Les B6 sont moins rapides sur le cintre, mais supérieurs aux A/J dans le labyrinthe aquatique, avec une plate-forme invisible ou visible. Ces résultats démontrent l’implication de déterminants génétiques. Cette thèse se termine par un quatrième article sur la localisation des déterminants génétiques de la susceptibilité au stress dans les RCS, dérivées de A/J et B6, et présentant un agencement spécifique de 12.5% du génome. La réactivité émotionnelle est évaluée dans l’OF et le plus-maze; la réponse de stress est mesurée par radio télémétrie de la température interne pendant le stress d’immobilisation (SI) sous diète régulière et riche en sel; l’excrétion des électrolytes urinaires est dosée après 24 heures de diète salée. Les loci les plus significatifs sont situés dans les régions suivantes: de l’émotionalité dans l’OF (Emo1) sur le chr. 1 (LOD=4.6) correspondant à la région homologue impliquée dans la cohorte d’hypertension familiale du Saguenay; de la dopa décarboxylase (ddc) sur le chr. 11 pour l’émergence du plus-maze (LOD=4.7); de la protéine liant l’endotoxine (lbp) sur le chr. 2 pour l’hypothermie initiale en réponse au SI (LOD=4); et de HSP90 sur le chr. 12 pour l’excrétion de Ca++ (LOD=4.6). Des banques de données sont ensuite interrogées pour recenser les polymorphismes des régions régulatrices ou codantes des gènes candidats chez les souches ancestrales A/J et B6, dont les séquences sont disponibles pour le génome entier. Des utilitaires web permettent de dévoiler les changements dans la structure secondaire de l’ARNm, l’interférence avec des microARN ou avec d’autres motifs de liaison. Plusieurs SNPs fonctionnels ont été identifiés pour le QTL du chr. 1, particulièrement dans les éléments de régulation; ceux-ci impliquant des gènes reliés avec les réponses inflammatoire/immunitaire ou avec le système cardiovasculaire. La quantification par la PCR confirme une régulation à la baisse d’atp1a2 dans le cœur et le cerveau des souches susceptibles à l’anxiété. Ces résultats confirment l’intrication des altérations de la susceptibilité au stress et de la régulation de la TA. / Our studies in this thesis, which led to 4 publications, are divided in two parts. The first part describes the neuropsychological effects of aging in strains of mice genetically selected for high (HBP), low (LBP) or normal blood pressure (NBP). The second part focuses on the genetic determinants of these neuropsychological phenotypes in recombinant congenic strains (RCS) of mice. The first manuscript compares HBP or LBP mice to normotensive controls in tests of exploration, motor coordination, and spatial learning at two age levels: 3 and 12 months. At either age, HBPs were hyperactive in an open field (OF) but not in terms of hole-poking responses. On the contrary, LBPs were hypoactive in the OF and in the hole-board, with the effect on the former measure being limited to the younger cohort. In either cohort, HBP and LBP mice were deficient in subtle aspects of motor coordination, and visuomotor function. These strains may serve as experimental models for the evaluation of beneficial early antihypertensive or antihypotensive treatments on brain function. The second study uses a longitudinal design to compare either HBP or LBP mice to normotensive controls at 2 and 12 months of age for motor coordination, anxiety, and spatial learning. Hyperactivity of HBPs in the OF increased with aging; whereas LBP mice were hypoactive only at 2 months of age. At both age, HBP and LBP mice displayed reduced levels of anxiety in the elevated plus-maze (EPM), abnormal coordination and visuomotor guidance. It remains to determine if these strain-, age-, and test-specific abnormalities are genetically related or secondary to uncontrolled hypertension or hypotension. The following article compares the C57BL/6J (B6) to the A/J inbred mouse strain in exploration of the OF and the hole-board, in the coat-hanger coordination test, and in spatial learning of a water maze. B6 mice displayed a higher number of segment crossings in the open-field and of hole-poking responses than A/J mice. By contrast to their hypo activity, A/J strain were faster in the coat-hanger motor test, but deficient in the submerged but also in the visible platform version of the water maze. These results indicate the considerable potential of genetic models derived from B6 and A/J mice for discerning the determinants of several behavioural phenotypes. In the last manuscript, the genomic loci bearing stress-related phenotypes were dissected by genome wide analysis of linkage in the recombinant congenic strains (RCS), resulting from a cross of B6 and A/J progenitors, each strain bearing 12.5% of specific parts of one progenitor on the background of the other. Adult male mice from 14 A/J and 22 B6 background lines were evaluated for emotional reactivity in the OF and the EPM. Core temperature was monitored by radio-telemetry during immobilization (IM), under standard and salt-enriched diets. In addition, urinary electrolytes were measured. The highest LOD scores strengthen the evidence for a previously reported locus for emotionality in the open-field on Chr 1 (LOD=4.6), in the Ddc region encoding dopa decarboxylase, on Chr 11 in the EPM (LOD=4.7), near Lbp (lipopolysaccharide binding protein), on Chr 2 for initial hypothermia during IM (LOD=4), as well as in the region of Hspca, encoding heat shock protein 1 alpha (48.0 cM) on Chr 12 for Ca++ excretion after a 24 hr-salt load (LOD=4.6). RCS stress QTL overlapped with several candidate loci for cardiovascular disease. In silico evidence of functional polymorphisms by comparative sequence analysis of progenitor strains assisted to ascertain this convergence, then further tested using quantitative PCR for releant genes mRNA. The anxious BcA70 strain showed down regulation of the Atp1a2 gene expression in the heart (P < 0.001) and brain (P < 0.05) compared to its parental B6 strain, compatible with the enhanced emotionality described in knock out animals for this gene, also involved in the salt-sensitive component of hypertension. Functional polymorphisms in regulatory elements of candidate genes of the cardiovascular / inflammatory / immune systems support the hypothesis of genetically-altered environmental susceptibility in cardiovascular disease development.
128

Investigating the role of potential genetic markers that can predict risk for steroid refractory inflammatory bowel disease

Krupoves, Alfreda 12 1900 (has links)
Contexte - La variation interindividuelle de la réponse aux corticostéroïdes (CS) est un problème important chez les patients atteints de maladies inflammatoires d’intestin. Ce problème est bien plus accentué chez les enfants avec la prévalence de la corticodépendance extrêmement (~40 %) élevée. La maladie réfractaire au CS a des répercussions sur le développement et le bien-être physique et psychologique des patients et impose des coûts médicaux élevés, particulièrement avec la maladie active comparativement à la maladie en rémission, le coût étant 2-3 fois plus élevé en ambulatoire et 20 fois plus élevé en hôpital. Il est ainsi primordial de déterminer les marqueurs prédictifs de la réponse aux CS. Les efforts précédents de découvrir les marqueurs cliniques et démographiques ont été équivoques, ce qui souligne davantage le besoin de marqueurs moléculaires. L'action des CS se base sur des processus complexes déterminés génétiquement. Deux gènes, le ABCB1, appartenant à la famille des transporteurs transmembraneaux, et le NR3C1, encodant le récepteur glucocorticoïde, sont des éléments importants des voies métaboliques. Nous avons postulé que les variations dans ces gènes ont un rôle dans la variabilité observée de la réponse aux CS et pourraient servir en tant que les marqueurs prédictifs. Objectifs - Nous avons visé à: (1) examiner le fardeau de la maladie réfractaire aux CS chez les enfants avec la maladie de Crohn (MC) et le rôle des caractéristiques cliniques et démographiques potentiellement liés à la réponse; (2) étudier l'association entre les variantes d'ADN de gène ABCB1 et la réponse aux CS; (3) étudier les associations entre les variantes d'ADN de gène NR3C1 et la réponse aux CS. Méthodes - Afin d’atteindre ces objectifs, nous avons mené une étude de cohorte des patients recrutés dans deux cliniques pédiatriques tertiaires de gastroentérologie à l’Ottawa (CHEO) et à Montréal (HSJ). Les patients avec la MC ont été diagnostiqués avant l'âge de 18 ans selon les critères standard radiologiques, endoscopiques et histopathologiques. La corticorésistance et la corticodépendance ont été définies en adaptant les critères reconnus. L’ADN, acquise soit du sang ou de la salive, était génotypée pour des variations à travers de gènes ABCB1 et NR3C1 sélectionnées à l’aide de la méthodologie de tag-SNP. La fréquence de la corticorésistance et la corticodépendance a été estimée assumant une distribution binomiale. Les associations entre les variables cliniques/démographiques et la réponse aux CS ont été examinées en utilisant la régression logistique en ajustant pour des variables potentielles de confusion. Les associations entre variantes génétiques de ABCB1 et NR3C1 et la réponse aux CS ont été examinées en utilisant la régression logistique assumant différents modèles de la transmission. Les associations multimarqueurs ont été examinées en utilisant l'analyse de haplotypes. Les variantes nongénotypées ont été imputées en utilisant les données de HAPMAP et les associations avec SNPs imputés ont été examinées en utilisant des méthodes standard. Résultats - Parmi 645 patients avec la MC, 364 (56.2%) ont reçu CS. La majorité de patients étaient des hommes (54.9 %); présentaient la maladie de l’iléocôlon (51.7%) ou la maladie inflammatoire (84.6%) au diagnostic et étaient les Caucasiens (95.6 %). Huit pourcents de patients étaient corticorésistants et 40.9% - corticodépendants. Le plus bas âge au diagnostic (OR=1.34, 95% CI: 1.03-3.01, p=0.040), la maladie cœxistante de la région digestive supérieure (OR=1.35, 95% CI: 95% CI: 1.06-3.07, p=0.031) et l’usage simultané des immunomodulateurs (OR=0.35, 95% CI: 0.16-0.75, p=0.007) ont été associés avec la corticodépendance. Un total de 27 marqueurs génotypés à travers de ABCB1 (n=14) et NR3C1 (n=13) ont été en l'Équilibre de Hardy-Weinberg, à l’exception d’un dans le gène NR3C1 (rs258751, exclu). Dans ABCB1, l'allèle rare de rs2032583 (OR=0.56, 95% CI: 0.34-0.95, p=0.029) et génotype hétérozygote (OR=0.52, 95% CI: 0.28-0.95 p=0.035) ont été négativement associes avec la dépendance de CS. Un haplotype à 3 marqueurs, comprenant le SNP fonctionnel rs1045642 a été associé avec la dépendance de CS (p empirique=0.004). 24 SNPs imputés introniques et six haplotypes ont été significativement associés avec la dépendance de CS. Aucune de ces associations n'a cependant maintenu la signification après des corrections pour des comparaisons multiples. Dans NR3C1, trois SNPs: rs10482682 (OR=1.43, 95% CI: 0.99-2.08, p=0.047), rs6196 (OR=0.55, 95% CI: 0.31-0.95, p=0.024), et rs2963155 (OR=0.64, 95% CI: 0.42-0.98, p=0.039), ont été associés sous un modèle additif, tandis que rs4912911 (OR=0.37, 95% CI: 0.13-1.00, p=0.03) et rs2963156 (OR=0.32, 95% CI: 0.07-1.12, p=0.047) - sous un modèle récessif. Deux haplotypes incluant ces 5 SNPs (AAACA et GGGCG) ont été significativement (p=0.006 et 0.01 empiriques) associés avec la corticodépendance. 19 SNPs imputés ont été associés avec la dépendance de CS. Deux haplotypes multimarqueurs (p=0.001), incluant les SNPs génotypés et imputés, ont été associés avec la dépendance de CS. Conclusion - Nos études suggèrent que le fardeau de la corticodépendance est élevé parmi les enfants avec le CD. Les enfants plus jeunes au diagnostic et ceux avec la maladie coexistante de la région supérieure ainsi que ceux avec des variations dans les gènes ABCB1 et NR3C1 étaient plus susceptibles de devenir corticodépendants. / Background - Inter-individual variation in response to treatment by corticosteroids (CS) is an important problem in the management of inflammatory bowel disease (IBD) patient’s. This problem is even more prominent in children, the prevalence of steroid dependence (~40%) in whom is extremely high. Steroid refractoriness has a considerable impact on the physical and psychological development of these children, also imposing high medical costs related to treatment. Active disease, as opposed to quiescent, increases medical costs 2-3 times in ambulatory patients and 20 times in hospitalized cases. Identifying markers that could predict steroid response is therefore a high clinical priority. Previous attempts to investigate potential clinical and demographic markers have been equivocal, highlighting the need for further investigations of other predictive markers. It is well known that the action of CS entails complex processes controlled by genetic factors. Two genes, the ABCB1 gene, which belongs to the family of trans-membrane transporters, and the NR3C1 gene, coding for the glucocorticoid receptor, are major elements of the pathway. We postulated that inter-individual variations in these genes may play a role in the observed variability of the response to CS and could serve as potential predictors. Objectives - We aimed to: (1) examine the burden of steroid refractoriness in children diagnosed with CD and explore the potential clinical/demographic factors related to CS response; (2) study the association between DNA variants in the ABCB1 gene and CS response; (3) investigate the associations between DNA variants in the NR3C1 gene and CS response. Methods - We investigated these objectives in a cohort of CD patients recruited from two tertiary paediatric gastroenterology clinics from Ottawa (CHEO) and Montreal (HSJ). CD patients diagnosed prior to age 18 using standard clinical, radiological, endoscopic and histopathological criteria were included. Published criteria were adapted to define CS-resistance and dependence. DNA acquired from blood and/or saliva was genotyped for variations across the ABCB1 and NR3C1 genes selected using the tag-SNP methodology. The frequencies of steroid resistance and dependence were estimated assuming a binomial distribution. Associations between clinical/demographic variables and steroid responses were examined using logistic regression modeling after accounting for potential confounding variables. Associations between ABCB1 and NR3C1 genes’ variants and steroid responses were examined using logistic regression assuming different models of inheritance. Multi-marker associations were examined via haplotype analysis. Un-genotyped variants in the genes were imputed using HAPMAP data as the reference panel and associations with imputed SNPs examined using standard methods. Results - Among 645 CD patients diagnosed at the study centers, 364 (56.2%) received corticosteroids during the first year since diagnosis. The majority of patients were male (54.9%), had inflammatory (84.6%), ileo-colonic (51.7%) disease phenotypes at diagnosis and were Caucasians (95.6%). Eight percent of patients developed CS-resistance and 40.9% became CS-dependent. Younger age at diagnosis (OR=1.34, 95% CI: 1.03-3.01, p=0.040), coexisting upper digestive tract involvement (OR=1.35, 95% CI: 1.06-3.07, p=0.031) and concomitant immunomodulators use (OR=0.35, 95% CI: 0.16-0.75, p=0.007) were significantly associated with CS-dependency in multivariate analysis. From among the 27 markers genotyped across the ABCB1 (n=14) and NR3C1 genes (n=13), all except one in NR3C1 gene (rs258751, excluded) were in Hardy-Weinberg Equilibrium. For ABCB1, the rare allele of rs2032583 (OR=0.56, 95% CI: 0.34-0.95, p=0.029) and heterozygous genotype (OR=0.52, 95% CI: 0.28-0.95, p=0.035) conferred protection from CS dependency. A 3-marker haplotype including the functional SNP rs1045642 was associated with CS-dependence (empiric p-value=0.004). On imputation 24 intronic SNPs and six haplotypes were statistically significantly associated with CS dependence. None of these associations however maintained significance after corrections for multiple comparisons. For the NR3C1 gene 3 SNPs, rs10482682 (OR=1.43, 95% CI: 0.99-2.08, p=0.047), rs6196 (OR=0.55, 95% CI: 0.31-0.95, p=0.024), and rs2963155 (OR=0.64, 95% CI: 0.42-0.98, p=0.039), showed associations under an additive model whereas rs4912911 (OR=0.37, 95% CI: 0.13-1.00, p=0.03) and rs2963156 (OR=0.32, 95% CI: 0.07-1.12, p=0.047) showed associations under a recessive model. Two haplotypes encompassing these 5 SNPs (AAACA and GGGCG) were significantly (empirical p=0.006 and 0.01 respectively) were associated with CS-dependence. On imputation 19 SNPs were associated with CS-dependence. Two multi-marker haplotypes (p-values=0.001 each) including genotyped and imputed SNPs conferred susceptibility for CS-dependency. Conclusions - Our studies suggest that the burden of steroid dependence is high among children with CD. Children diagnosed at a younger age, those with co-existent upper tract disease and with variations in the ABCB1 and NR3C1 genes were more likely to become CS dependent.
129

Investigation des variants génétiques dans la dysfonction endothéliale et le risque de maladies cardiovasculaires.

Codina-Fauteux, Valérie-Anne 08 1900 (has links)
No description available.
130

Genetic diversity of " brain genes" across worldwide

Gardner, Michelle 25 June 2007 (has links)
El treball presentat en aquesta tesi és un estudi de la diversitat genètica en un conjunt de gens implicats en funcions neurològiques ("Gens cerebrals"). Hom ha examinat vint-i-dos gens implicats en els sistemes de neurotransmissió dopaminèrgic, serotoninèrgic i glutamatèrgic. L'objectiu de l'estudi té dos vessants: per una banda l'anàlisi de la diversitat genètica en un conjunt de gens implicats en malaltia humana, en aquest cas en malaltia psiquiàtrica, en poblacions humanes mundials, amb la intenció d'assentar les bases per propers esforços de mapatge genètic; i per altra banda analitzar la diversitat genètica en aquest conjunt de gens per tal de descobrir evidències d'esdeveniments històrics, incloent possibles evidències de selecció. / The work presented in this thesis is a study of the genetic variation in a set of genes related to neurological function ('Brain genes'). Twenty two genes are examined, all of which are involved in either the Dopaminergic, Serotonergic or the Glutamatergic systems of neurotransmission.The objective of the study has two aspects: on the one hand the analysis of genetic variation in a set of genes which are implicated in human disease, in this case psychiatric disease, across global human populations, towards the end of providing some new insight for gene mapping efforts, and on the other hand the study of genetic variation in this set of genes may reveal traces of the population history events undergone, including possible evidence for selection.

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