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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.
221

Utilização de células foliculares ovarianas para o aprimoramento de técnicas de reprodução assistida e para a compreensão da falência ovariana precoce

Alcoba, Diego Duarte January 2016 (has links)
A infertilidade é uma condição clínica que acomete até 15% dos casais em idade reprodutiva. Como forma de tratamento para essa parcela da população a Medicina Reprodutiva dispõe de várias técnicas de Reprodução Assistida que visam auxiliar o casal na obtenção da gestação. O primeiro passo para obtenção de sucesso na Medicina Reprodutiva é o correto diagnóstico da infertilidade e, do ponto de vista didático, as causas de infertilidade podem ser classificadas em: feminina, masculina, mista ou desconhecida. A causa feminina de infertilidade apresenta como importante fator o ovariano, representado, principalmente, por alterações no processo de maturação do oócito e/ou no processo de foliculogênese. Com relação à maturação do oócito, um dos possíveis tratamentos oferecidos pela Medicina Reprodutiva é a aplicação da técnica de maturação in vitro (MIV). Infelizmente a MIV não apresenta resultados animadores, e um dos motivos é a falta de um método adequado de seleção dos gametas de humanos que podem ser destinados à ela. No entanto, várias técnicas de seleção de oóticos já foram descritas para espécies animais; dentre elas destaca-se a coloração dos complexos cumuli-oócitos com o corante Azul Cresil Brilhante (BCB). A sua aplicação na espécie humana permanece com ressalvas, uma vez que a comunidade científica preocupa-se com os possíveis efeitos tóxicos dessa substância. Nesta Tese, conseguimos demonstrar, através da avaliação de ensaios de viabilidade e de proliferação celular, e da expressão gênica e proteica, a inocuidade dessa substância para o modelo de cultura primária de células foliculares ovarianas luteinizadas, indicando que o protocolo de coloração com BCB é seguro para a espécie humana. Adicionalmente, conseguimos caracterizar e padronizar o cultivo dessas células, que são amplamente utilizadas em estudos na área da Medicina Reprodutiva. Com relação ao outro fator ovariano de infertilidade (o processo de foliculogênese), sabe-se que a depleção acelerada dos folículos ovarianos pode provocar falência ovariana precoce (FOP), uma condição clínica que acomete até 1% das mulheres em idade reprodutiva e leva à infertilidade. Uma das causas da FOP é a alteração no gene Fragile X Mental Retardation 1 (FMR1) e consequentemente em sua proteína (FMRP). Muito do conhecimento do controle dessa proteína provem de experimentos em neurônios, onde o seu controle já foi elucidado. Nesta Tese, conseguimos demonstrar que o controle dessa proteína nas células ovarianas de humanos é similar ao controle que ocorre nos neurônios, envolvendo a via de sinalização S6K. / Infertility is a clinical condition that affects up to 15% of couples of reproductive age. Reproductive medicine applies many assisted reproductive technologies (ARTs) in order to help them to achieve pregnancy. The first step for infertility treatment success is the correct infertility diagnosis, which is divided into four categories: female, male, mixed or unknown. Female infertility is chiefly represented by ovarian dysfunctions, which are generally related to oocyte maturation and/or folliculogenesis. With regard to oocyte maturation, in vitro oocyte maturation (IVM) is one ART that can be applied but, unfortunately, nowadays it does not present suitable results, since we do not have an effective method of selecting competent human oocytes. On the other hand, in animal reproduction brilliant cresyl blue (BCB) staining has already been described as an appropriate method for oocyte selection. However its clinical applicability to humans is some away off, owing to concerns about its safety. In this thesis we have demonstrated (through many cellular viability and proliferation assays and gene and protein expression), that BCB staining, applying the correct protocol, seems to be safe for use in humans (using the primary culture of human ovarian follicular cells as an experimental model). Additionally, we have characterized and standardized the primary culture of human ovarian follicular cells, and this experimental model is widely applied in reproductive medicine experiments. With regard to folliculogenesis, it is well known that premature ovarian failure/insufficiency (POF/POI) is one condition that can be caused by follicle depletion (when folliculogenesis occurs too fast). This condition affects about 1% of females of reproductive age, causing infertility. Genetic alterations, such as in the fragile X mental retardation 1 (FMR1) gene and its protein FMRP, are considered as one cause of POF/POI. Most of our knowledge about FMRP cellular control comes from studies on neurons, and in these cells we have a clue about its control. In this thesis, we have shown that FMRP control on human granulosa cells is similar to its control on neurons, and this involves the S6K pathway.
222

Apport des méthodes de survie nette dans le pronostic des lymphomes malins non hodgkiniens en population générale / Contribution of net survival methods to the prognosis of Non-Hodgkin lymphoma in population studies

Mounier, Morgane 17 September 2015 (has links)
L'étude de la survie nette des patients atteints de cancer en population générale permet d'apprécier l'efficience globale du système de soin d'un pays. La survie nette se définit comme la survie qui serait observée si la seule cause de décès possible était le cancer. Ce concept est fondamental dans les comparaisons entre zones géographiques et/ou périodes de diagnostic dont l'intérêt est d'estimer les variations spécifiques de la mortalité due au cancer. Le concept de survie nette permet de prendre en compte les éventuelles différences de mortalité naturelle entre les groupes comparés. Actuellement, seuls deux outils estiment la survie nette sans biais : l'estimateur non paramétrique de Pohar-Perme et la modélisation paramétrique ajustée sur certaines covariables (essentiellement l'âge). Par ailleurs, les outils paramétriques s'étant perfectionnés, de nouveaux modèles flexibles permettent de modéliser les effets complexes des variables sur la mortalité. Ce travail repose sur la modélisation du taux de mortalité en excès à la suite d'un lymphome malin non hodgkinien, en se basant sur le modèle proposé par Remontet et al. et sur la nécessité de modéliser conjointement les effets complexes des covariables (telles que le temps de suivi, l'année de diagnostic et l'âge) sur la mortalité à l'aide d'une stratégie de modélisation adaptée. L'effet des variables est restitué sur la survie nette mais aussi sur le taux de mortalité en excès ce qui représente un élément nouveau dans les études de survie. Deux applications ont été menées sur des bases de données collaboratives de population : d'une part sur les données françaises du réseau FRANCIM à la suite d'un diagnostic de lymphome folliculaire entre 1995 et 2010 et, d'autre part, sur les données européennes d'EUROCARE-5 après un lymphome folliculaire ou un lymphome B diffus à grandes cellules diagnostiqué entre 1996 et 2004. Les résultats montrent que la dynamique du taux de mortalité en excès au cours du temps de suivi varie en fonction du sous-type de lymphome, de l'âge et de la zone géographique. Les tendances de cette dynamique en fonction de l'année de diagnostic sont également différentes / The net survival of cancer patients in population studies is the most relevant indicator to assess the overall efficiency of the healthcare system of a country. Net survival is defined as the survival that would be observed if the sole cause of death were cancer. This concept is crucial in comparative studies (between geographical areas and/or periods of diagnosis) that estimate specific variations of cancer-related deaths. Net survival takes into account potential differences in mortality patterns between groups. Currently, two methods provide unbiased estimations of net survival: the non-parametric estimator of Pohar-Perme and the parametric model adjusted on specific covariates (mainly, the age at diagnosis). Moreover, new improved parametric tools, such as flexible models, can model the complex covariate effects on mortality. In this work, we modeled the excess mortality rate after a non Hodgkin lymphoma diagnosis, with a model developed by Remontet et al. In addition, we used an appropriate model-building-strategy to model jointly the complex effects of some covariates (such as the time elapsed since diagnosis, the year of diagnosis, and age) on the excess mortality. Finally, this approach allowed for the covariate effects on the net survival and on the excess mortality rate. We applied this method to two different collaborative databases: first on the French database FRANCIM (1995 to 2010) to study the excess mortality after diagnosis of follicular lymphoma, then on the European data of EUROCARE-5 (1996 to 2004) to study the excess mortality after diagnosis of follicular lymphoma and diffuse large B-cell lymphoma. According to the results, the dynamics of the excess mortality rate varies over the time elapsed since diagnosis according to the lymphoma subtype, the age, and the geographical area. The trends of these dynamics over the years of diagnosis are different too
223

La neuropiline 1 et le récepteur alpha à l’IL-2 (CD25) : expression et implication dans l’homéostasie des lymphocytes T chez l’homme dans un contexte normal ou pathologique / Neuropilin 1 and IL-2 receptor alpha (CD25) : expression and implication in normal or pathologic human T cell homeostasis

Renand, Amédée 23 June 2011 (has links)
Des études récentes ont montré une implication de la neuropiline 1 (Nrp1)dans le contrôle de l’activation des lymphocytes T. Son invalidation s’accompagne d’une aggravation de l’encéphalite auto-immune expérimentale (EAE). La sémaphorine 3A (Sema-3A), ligand principal de la Nrp1, semble participer à une boucle autocrine de rétro contrôle négatif de la prolifération des lymphocytes T.Cependant, peu d’études ont été réalisées chez l’homme pour déterminer dans quelle(s) situation(s) la Nrp1 est exprimée par les lymphocytes T. Notre travail aconsisté à étudier l’expression de la Nrp1 par les populations lymphocytaires T humaines afin de comprendre à quel niveau peut avoir lieu ce rétro contrôle. Nous montrons que les lymphocytes T régulateurs (Treg) chez l’homme n’expriment pas laNrp1, contrairement aux Treg murins. En revanche, la Nrp1 est exprimée par les lymphocytes T effecteurs après engagement avec l’antigène, soit au niveau des organes lymphoïdes secondaires pour les lymphocytes T folliculaires helper (Tfh) en interaction avec les lymphocytes B, soit au niveau des sites d’inflammations périphériques pour les lymphocytes T effecteurs mémoires (TEM). Dans les deux cas, cette expression survient en fin d’activation et pourrait servir de frein à une activation incontrôlée des lymphocytes T.D’autre part, nous avons abordé le rôle du récepteur alpha à l’IL-2 (CD25)dans l’homéostasie des lymphocytes T. L’étude chez la souris il2ra-/- a révélé un rôle important du CD25 pour la survie des Treg in vivo, mais aussi pour l’acquisition de lymphocytes T mémoires. Seulement deux cas de déficience en CD25, associés à des maladies auto-immunes, ont été décrits chez l’homme. Cependant, ces études n’ont pas abordé à quel niveau le CD25 intervient sur l’homéostasie des lymphocytes T. Nous complétons ces études par la présentation de trois nouveaux cas de déficience en CD25 développant des maladies auto-immunes de type IPEX. Nous montrons que le CD25 intervient activement dans le maintien des populations Treg naïves et effectrices, mais aussi dans celui des populations lymphocytaires effectrices mémoires. / Recent studies have shown the involvement of neuropilin 1 (Nrp1) in the control of T cell activation, and disruption of this receptor promotes aggravation of experimental autoimmune encephalitis (EAE). Through its principal ligand,semaphorin 3A (Sema-3A), Nrp1 appears to participate in an autocrine negative feedback of T cell proliferation. However, few studies have been conducted inhumans to determine when Nrp1 is expressed by T cells. Here we show that regulatory T cells (Treg) in humans do not express Nrp1, unlike murine Treg cells. In contrast, we show that Nrp1 is expressed by effector T cells after engagement with antigen, either in secondary lymphoid organs for follicular helper T cells (Tfh) interacting with B cells, either in peripheral inflammation for effector memory T cells(TEM). We conclude that this expression corresponds to a level of late activation in both cases and may control T cell activation.The study in mice il2ra-/- revealed a significant role of IL-2 receptor alpha(CD25) for the survival of Treg in vivo, but also for the differentiation of memory T cells. Only two cases of CD25 deficiency associated with autoimmune diseases have been described in humans. However, these studies do not assess at what levelCD25 is involved in T cell homeostasis. Here we provide further insight of these studies by presenting three new cases of CD25 deficiency developing autoimmune diseases like IPEX. We show that CD25 plays an active role to maintain naive and effector Treg cell populations of, and effector memory T cell populations.
224

Modulation de la balance lymphocytaire T régulatrice et effectrice dans deux modèles de maladies auto-immunes / Modulation of regulatory T cells and effector T celles balance in two models of autoimmune diseases

Jacquemin, Clément 22 October 2013 (has links)
Le respect de l’équilibre entre lymphocytes T effecteurs auto-réactifs et lymphocytes T régulateurs (LTreg) est primordial dans le maintien de la tolérance aux antigènes du soi. Les partenaires cellulaires et les mécanismes moléculaires impliqués dans la rupture de l’équilibre de cette balance ne sont pas ou peu connus dans les maladies auto-immunes. Ainsi, les travaux décrits dans cette thèse portent sur le dérèglement de la balance T effecteurs/ Treg dans deux modèles de maladies auto-immunes chez l’homme: le lupus érythémateux systémique et l’anémie hémolytique auto-immune (AHAI). Nous montrons une augmentation de l’expression de la molécule de costimulation OX40L (CD252, TNFSF4) à la surface des cellules présentatrices d’antigène circulantes et infiltrant les tissus chez les patients lupiques. Cette augmentation est corrélée à l’activité de la maladie chez l’adulte comme chez l’enfant. Elle a pour conséquence l’induction de lymphocytes T effecteurs de type Tfh (T follicular helper) et le blocage des fonctions suppressives des Treg, deux acteurs majeurs dans la physiopathologie du lupus. Dans le second projet, nous montrons une augmentation de la proportion de T8reg circulants chez les patients affectés d’une AHAI à anticorps chauds en phase de rémission. Ces Treg expriment le CD25, le FoxP3 et exercent leur fonction suppressive par un mécanisme faisant intervenir l’IL10. De faibles doses d’IL-2 permettent l’expansion de cette population cellulaire in vitro. Ces résultats apportent de nouvelles connaissances dans la physiopathologie de ces deux maladies et offrent des perspectives thérapeutiques potentielles. / Respect of the balance between autoreactive T cells and regulatory T cells (LTreg) is important to maintain tolerance to self-antigens. Cellular partners and molecular mechanisms involved in the disruption of this balance are not or little known in autoimmune diseases.Thus, the work described in this thesis focuses on the disruption of the T effector/ Treg balance in two models of human autoimmune diseases: systemic lupus erythematosus and autoimmune hemolytic anemia (AIHA). We show an increased expression of the OX40L (CD252, TNFSF4) costimulatory molecule at the surface of both circulating and tissues-infiltrating antigen presenting cells in SLE patients. OX40L expression is correlated with disease activity in adults and in children and results in Tfh (follicular helper T) effector cells induction and Treg suppressive functions inhibition, two key mechanisms in the pathogenesis of lupus. In the second project, we show an increase of the circulating T8reg proportion in patients with a warm AIHA in a non-active state. These Treg express CD25, FoxP3 and exert their suppressive function by a mechanism involving IL-10. Low-dose IL-2 allows the expansion of this cell population in vitro. These results provide new insights into the pathophysiology of these diseases and offer potential therapeutic perspectives.
225

Efeitos da exposição pré-concepcional de curta duração ao material particulado ambiental sobre o mecanismo reprodutivo feminino / Effects of short-term preconceptional exposure to ambient particulate matter on female reproductive function

Paulo Marcelo Perin 25 July 2008 (has links)
Um Projeto Temático de Pesquisa foi desenvolvido no Laboratório de Poluição Ambiental do Departamento de Patologia da Faculdade de Medicina da Universidade de São Paulo com o objetivo de avaliar os efeitos da exposição aguda/crônica ao ar ambiente de um grande centro urbano sobre a saúde. Dentro deste projeto, uma linha de pesquisa foi dedicada ao estudo dos efeitos dessa exposição sobre a saúde reprodutiva feminina. Evidências de estudos epidemiológicos e experimentais implicam os fatores ambientais na infertilidade humana e resultado obstétrico adverso. Contudo, poucos estudos foram conduzidos até o presente para avaliar um possível efeito da exposição à poluição ambiental particulada sobre a saúde reprodutiva feminina. Portanto, o objetivo dos projetos da minha linha de pesquisa é fornecer dados que possam demonstrar os possíveis efeitos da exposição pré-concepcional de curta duração às partículas de exaustão do diesel (PED) e à poluição ambiental particulada sobre a função ovariana, o desenvolvimento embrionário inicial e resultado gestacional utilizando um modelo experimental e um epidemiológico. O objetivo do primeiro projeto desta tese foi avaliar os efeitos de dois meios de cultura comerciais no desenvolvimento de oócitos de camundongo fertilizados in vitro até o estágio de blastocisto. Zigotos obtidos de fêmeas de camundongo de 8 semanas de idade submetidas à indução da ovulação foram cultivados in vitro até o estágio de blastocisto em meio simples otimizado enriquecido com potássio (KSOM) ou meio G1/G2. A porcentagem de zigotos que se desenvolveu até o estágio de blastocisto 96 e 120 horas após a inseminação e que sofreu eclosão parcial ou completa no quinto dia de cultivo foi significativamente maior no grupo KSOM. O número médio de células da massa celular interna (MCI) foi 11,7 ± 4,0 e 9,2 ± 5,2 para os zigotos cultivados nos grupos KSOM e G1/G2, respectivamente, mostrando um número significativamente maior de células MCI em blastocistos derivados da cultura no meio KSOM. Concluímos que o meio KSOM comercialmente disponível é superior ao meio seqüencial G1/G2 para o cultivo de zigotos até o estágio de blastocisto no modelo de fertilização in vitro (FIV) em camundongos. No segundo projeto que compõe esta tese, o objetivo foi avaliar os efeitos da exposição de curta duração às PED sobre a fertilização, desenvolvimento embrionário e segregação das linhagens celulares em blastocistos pré-implantacionais utilizando o modelo de FIV em camundongo. A instilação intranasal de água destilada (grupo controle), de PED nativas (grupo PED-N) ou de PED ácidoextraídas (grupo PED-AE), realizada uma vez ao dia por três dias, iniciada no primeiro dia de administração de gonadotrofinas, foi realizada em fêmeas de camundongo com oito semanas de idade. Os pontos de avaliação reprodutivos analisados incluíram a resposta ovariana a estimulação, taxa de fertilização, desenvolvimento embrionário, taxas de formação e de eclosão dos blastocistos, contagem celular total e proporção da alocação celular à MCI e trofoectoderma (TE), e a morfologia da MCI. A resposta ovariana não foi afetada pelo protocolo de exposição. Um efeito multivariado para a exposição às PED-N e PED-AE na coloração diferencial de blastocistos e na morfologia da MCI, mas não para a FIV ou desenvolvimento embrionário, foi observado. A contagem celular da MCI e a razão MCI/TE em blastocistos produzidos no grupo controle foram significativamente maiores do que em blastocistos produzidos nos grupos PED-N e PED-AE. O número total de células dos blastocistos foi similar entre os grupos. O escore que representa a morfologia da massa celular interna foi significativamente maior no grupo controle quando comparado àquele encontrado nos grupos PED-N e PEDAE. Baseando-se nesses resultados, nosso estudo sugere que a exposição de curta duração às PED pode afetar negativamente o processo reprodutivo através do distúrbio da especificação das linhagens celulares do embrião em estágio de blastocisto. Finalmente, a exposição a toxinas ambientais pode ser inevitável durante o período pré-concepcional em grandes centros urbanos e seus efeitos são desconhecidos. Portanto, o propósito do terceiro projeto que compõe esta tese foi avaliar os potenciais efeitos da exposição de curta duração à poluição ambiental particulada durante a fase folicular sobre os resultados clínicos, laboratoriais e gestacionais de casais submetidos à fertilização in vitro e transferência de embriões (FIVETE). Trezentos e quarenta e oito mulheres submetidas ao seu primeiro ciclo de FIVETE foram avaliadas retrospectivamente neste estudo coorte, casocontrole casado. A exposição ao material particulado ambiental (MP) durante a fase folicular de cada paciente foi estimada baseando-se em dados da poluição ambiental (1997-2006) categorizados em período Q1-3 ( 56,72 g/m3) e Q4 (>56,72 g/m3). Desse grupo, 177 pacientes que engravidaram (casos) foram comparadas com 354 mulheres que conceberam espontaneamente (controles). Os principais pontos de avaliação incluíram a resposta ovariana às gonadotrofinas, o número de oócitos recuperados e as taxas de fertilização, de clivagem, de qualidade embrionária, de implantação, de gestação, de abortamento e de nascidos vivos. Nenhum efeito da exposição a níveis elevados de MP durante a fase folicular foi observado nos resultados clínico e laboratorial, na transferência embrionária ou no sucesso dos ciclos de tratamento das pacientes submetidas à FIVETE. Mulheres expostas ao período Q4 durante a fase folicular do ciclo de concepção apresentaram um risco significativamente maior de abortamento, independentemente do método de concepção (razão de chance: 2,58; intervalo de confiança de 95%: 1,63 4,07), quando comparado àquele de mulheres expostas ao período Q1-3. O risco de perda da gestação aumentou 3% por unidade de aumento do valor médio do MP na fase folicular (p= 0,000). Os resultados apresentados aqui fornecem evidências para uma relação causal entre a breve exposição a níveis elevados de MP ambiente durante o período pré-concepcional e a perda gestacional inicial, independentemente do método de concepção e está associada a um aumento de 2,6 vezes no risco de abortamento. Apesar da ausência de efeitos dessa exposição sobre os resultados clínicos e laboratoriais e sobre o sucesso do tratamento, a FIVETE foi incapaz de reduzir esse risco / A thematic research project to evaluate the health effects of acute/chronic exposure to ambient air in a large urban center was developed at the Air Pollution Laboratory in the Department of Pathology at the University of São Paulo School of Medicine. Within this project a specific research line was committed to the study of the effects of this exposure on female reproductive health. Evidence from epidemiological and experimental studies implied environmental factors as possible contributors to human infertility and poor obstetric outcome. However, very few studies evaluating a possible effect of exposure to particulate air pollution on female reproductive health have been conducted so far. Thus, the aim of the projects in my research line was to provide data that could show the possible effects of short-term preconceptional exposure to diesel exhaust particles and particulate air pollution on ovarian function, early embryo development and pregnancy outcome using experimental and epidemiological models. The objective of the first project was to examine the effects of two commercial media on the development of mouse ova fertilized in vitro to the blastocyst stage. One-cell embryos obtained from eight-week old superovulated mice were cultured in vitro up to the blastocyst stage in potassium-enriched simplex optimized medium (KSOM) or G1/G2 media. The percentage of zygotes that developed to the blastocyst stage 96 and 120 hours after insemination and that partially or completely hatched by day five of culture was significantly higher in the KSOM group. The mean number of inner cell mass (ICM) cells was 11.7 ± 4.0 and 9.2 ± 5.2 for zygotes cultured in KSOM and G1/G2 groups respectively, revealing a significantly higher cell number in the ICM of blastocysts derived from culture in KSOM medium. I concluded that commercially available KSOM medium is superior to sequential G1/G2 media for culturing one-cell embryos up to the blastocyst stage in the mouse IVF model. In the second project the objective was to evaluate the effects of short-term exposure to diesel exhaust particles on fertilization, embryo development, and cell lineage segregation in preimplantation blastocysts using the mouse IVF model. Intranasal instillation of distilled water (control group), native diesel exhaust particles (N-DEP group) or acid-extracted diesel exhaust particles (AE-DEP) once a day, for three days starting on the first day of gonadotrophin administration was performed on eight-week old female mice. Reproductive endpoints evaluated included ovarian response to superovulation, fertilization rate, embryo development, blastocyst and hatching rates, total cell count, and proportion of cell allocation to ICM and trophectoderm (TE), and ICM morphology. Ovarian response was not affected by the exposure protocol. A multivariate effect for exposure to NDEP and AE-DEP on blastocyst differential staining and ICM morphology but not on IVF or embryo development was found. Cell counts in ICM and ICM/TE ratios in blastocysts produced in the control group were significantly higher than in blastocysts produced in N-DEP and AE-DEP groups. The total cell count was similar among groups. The score that represents ICM morphology was significantly higher in the control group when compared to that found in N-DEP and AE-DEP groups. Based on these results this study suggests that short-term exposure to DEP may negatively affect the reproductive process by disrupting the lineage specification at the blastocyst stage. Finally, exposure to environmental toxins may be unavoidable during the preconceptional period in large urban centers and its effects are unknown. Thus, the purpose of the third project was to assess the potential effects of short-term exposure to particulate air pollution during the follicular phase on clinical, laboratory, and pregnancy outcomes for couples undergoing IVF/ET. Three hundred forty-eight patients undergoing their first IVF/ET cycle were evaluated in this retrospective cohort-matched casecontrolled single-center study. Exposure to ambient particulate matter (PM) during the follicular phase for each patient was estimated based on air pollution data (1997-2006) categorized in Q1-3 ( 56.72 g/m3) and Q4 (>56.72 g/m3) periods. From this group 177 women who became pregnant (cases) were compared with 354 who had conceived spontaneously (controls). Main outcome measures included response to gonadotrophins, number of oocytes retrieved, fertilization, cleavage, embryo quality, implantation, pregnancy, miscarriage, and live birth rates. No effects of follicular phase exposure to high levels of PM on clinical, laboratory, embryo transfer or treatment outcome were found in women undergoing IVF/ET. Women exposed to Q4 level PM during the follicular phase of the conception cycle had significantly higher risk of miscarriage, regardless of the method of conception (odds ratio, 2.58; 95% confidence interval: 1.63-4.07) when compared to women exposed to Q1-3 level PM. The risk of miscarriage increased 3% per unit increase in follicular phase PM average level (p=0.000). The results presented here provide evidence of a causal role for brief exposure to high levels of ambient PM during the preconceptional period in early pregnancy loss, regardless of the method of conception, with a 2.6-fold increase in risk of miscarriage. Despite the absence of effects of this exposure on clinical, laboratory, and treatment outcome, IVF/ET was unable to reduce this risk
226

Endocrine and molecular regulation of ovarian antral follicular wave emergence and growth in sheep

Seekallu, Srinivas 21 October 2009
In sheep, large ovarian antral follicles grow in waves with a periodicity of every 4 to 5 days; each wave is initiated by a peak in serum concentrations of follicle stimulating hormone (FSH). In the present thesis, follicular data and hormone estimations acquired from daily ultrasonography and blood samples, respectively, were used to study mechanisms regulating the number of follicular waves per estrous cycle. Using additional approaches such as implants releasing estradiol-17â and or progesterone, immunization against gonadotropin releasing hormone (GnRH), and injections of GnRH, the role of pulsed luteinizing hormone (LH) secretion and FSH peaks in follicular wave emergence and growth and the dependency of FSH peaks on pulsed GnRH secretion, were studied in sheep. The viability of aged follicles was also addressed.<p> The results of the present studies showed that ewes with three or four waves per cycle had cycles of the same length. The inter-wave interval was longer for the first and the last or ovulatory wave of the cycle in three compared to four wave cycles. The length of the lifespan and regression phase of the largest follicle of a wave declined across the cycle as FSH peak concentration and amplitude decreased. The maximum follicular diameter of the largest follicle growing in the first wave and the last or ovulatory wave of the cycle was greater compared to other waves of the cycle. Treatment of anestrous ewes with estradiol releasing implants alone completely abolished pulsed LH secretion and suppressed follicular wave development; however, FSH secretion was only minimally affected and the pool of small follicles was not affected. When pulsed secretion of LH was restored by frequent injections of GnRH, follicular waves were re-established. Treatment of anestrous ewes with implants releasing estradiol and progesterone, decreased FSH peak amplitude and abolished LH pulses and follicular waves; the size of the pool of small follicles increased. Immunization against GnRH in anestrous ewes abolished pulsatile LH secretion and suppressed follicular wave emergence; however, FSH peaks continued to occur for several weeks. In cyclic ewes, creating an LH pulse frequency typical of the follicular phase, during the luteal phase of the cycle by giving GnRH, increased maximum diameter of the largest follicle in a wave and serum concentrations of estradiol and progesterone. The enhanced growth of follicles in a wave blocked the next expected FSH peak and its associated follicular wave. Decreasing LH pulse frequencies lower than the minimal frequency seen in the luteal phase, by implants releasing progesterone, did not affect the growth of follicular waves.<p> It was previously demonstrated that treatment of non-prolific WWF ewes with Prostaglandin F2á (PGF2á) and medroxy progesterone acetate (MPA) increased the ovulation rate by adding ovulations from the penultimate wave in addition to the final wave of the cycle; however, fertility was not improved. In the last study of my thesis, we collected follicles, with an extended lifespan, from the penultimate wave of the cycle in ewes given the PGF2á and MPA treatment. We compared their quality with follicles from the final wave of the cycle by looking at the expression of markers of follicular development. The results showed that theca cells of follicles from the final wave had significantly higher mRNA expression for vascular endothelial growth factor (VEGF) compared to follicles from the penultimate wave. Granulosa cells of follicles from the final wave had significantly higher mRNA expression for connexion 43 (Cx43) compared to follicles from the penultimate wave. Protein expression for Cx43, proliferating cell nuclear antigen (PCNA) and Factor VIII was greater in follicles from the final compared to the penultimate wave.<p> We concluded from the present studies that: 1) the mechanism that makes a three wave or four wave cycle is unclear; 2) some level of pulsatile LH secretion is required for an FSH peak to trigger emergence of follicular waves in anestrous ewes; 3) progesterone enhances the inhibitory effects of estradiol on FSH secretion in anestrous ewes, suppressing specifically FSH peak amplitude; 4) an endogenous rhythm may exist that drives the peaks in FSH secretion independent of secretory products from the follicles growing in a wave and pulsed GnRH secretion; 5) follicular waves in ewes, when exposed to an LH pulse frequency similar to the follicular phase, during the luteal phase of the cycle, when serum progesterone concentrations are high, can grow and function like ovulatory follicles growing in the follicular phase of the cycle; 6) expression of some markers of vascularization/ angiogenesis, gap-junctional communication and cell proliferation, appeared to be decreased in follicles from the penultimate compared to the final wave of an estrous cycle, when the lifespan of follicles from the penultimate wave was extended such that they were present in the ovary with follicles from the final wave of the cycle.
227

Endocrine and molecular regulation of ovarian antral follicular wave emergence and growth in sheep

Seekallu, Srinivas 21 October 2009 (has links)
In sheep, large ovarian antral follicles grow in waves with a periodicity of every 4 to 5 days; each wave is initiated by a peak in serum concentrations of follicle stimulating hormone (FSH). In the present thesis, follicular data and hormone estimations acquired from daily ultrasonography and blood samples, respectively, were used to study mechanisms regulating the number of follicular waves per estrous cycle. Using additional approaches such as implants releasing estradiol-17â and or progesterone, immunization against gonadotropin releasing hormone (GnRH), and injections of GnRH, the role of pulsed luteinizing hormone (LH) secretion and FSH peaks in follicular wave emergence and growth and the dependency of FSH peaks on pulsed GnRH secretion, were studied in sheep. The viability of aged follicles was also addressed.<p> The results of the present studies showed that ewes with three or four waves per cycle had cycles of the same length. The inter-wave interval was longer for the first and the last or ovulatory wave of the cycle in three compared to four wave cycles. The length of the lifespan and regression phase of the largest follicle of a wave declined across the cycle as FSH peak concentration and amplitude decreased. The maximum follicular diameter of the largest follicle growing in the first wave and the last or ovulatory wave of the cycle was greater compared to other waves of the cycle. Treatment of anestrous ewes with estradiol releasing implants alone completely abolished pulsed LH secretion and suppressed follicular wave development; however, FSH secretion was only minimally affected and the pool of small follicles was not affected. When pulsed secretion of LH was restored by frequent injections of GnRH, follicular waves were re-established. Treatment of anestrous ewes with implants releasing estradiol and progesterone, decreased FSH peak amplitude and abolished LH pulses and follicular waves; the size of the pool of small follicles increased. Immunization against GnRH in anestrous ewes abolished pulsatile LH secretion and suppressed follicular wave emergence; however, FSH peaks continued to occur for several weeks. In cyclic ewes, creating an LH pulse frequency typical of the follicular phase, during the luteal phase of the cycle by giving GnRH, increased maximum diameter of the largest follicle in a wave and serum concentrations of estradiol and progesterone. The enhanced growth of follicles in a wave blocked the next expected FSH peak and its associated follicular wave. Decreasing LH pulse frequencies lower than the minimal frequency seen in the luteal phase, by implants releasing progesterone, did not affect the growth of follicular waves.<p> It was previously demonstrated that treatment of non-prolific WWF ewes with Prostaglandin F2á (PGF2á) and medroxy progesterone acetate (MPA) increased the ovulation rate by adding ovulations from the penultimate wave in addition to the final wave of the cycle; however, fertility was not improved. In the last study of my thesis, we collected follicles, with an extended lifespan, from the penultimate wave of the cycle in ewes given the PGF2á and MPA treatment. We compared their quality with follicles from the final wave of the cycle by looking at the expression of markers of follicular development. The results showed that theca cells of follicles from the final wave had significantly higher mRNA expression for vascular endothelial growth factor (VEGF) compared to follicles from the penultimate wave. Granulosa cells of follicles from the final wave had significantly higher mRNA expression for connexion 43 (Cx43) compared to follicles from the penultimate wave. Protein expression for Cx43, proliferating cell nuclear antigen (PCNA) and Factor VIII was greater in follicles from the final compared to the penultimate wave.<p> We concluded from the present studies that: 1) the mechanism that makes a three wave or four wave cycle is unclear; 2) some level of pulsatile LH secretion is required for an FSH peak to trigger emergence of follicular waves in anestrous ewes; 3) progesterone enhances the inhibitory effects of estradiol on FSH secretion in anestrous ewes, suppressing specifically FSH peak amplitude; 4) an endogenous rhythm may exist that drives the peaks in FSH secretion independent of secretory products from the follicles growing in a wave and pulsed GnRH secretion; 5) follicular waves in ewes, when exposed to an LH pulse frequency similar to the follicular phase, during the luteal phase of the cycle, when serum progesterone concentrations are high, can grow and function like ovulatory follicles growing in the follicular phase of the cycle; 6) expression of some markers of vascularization/ angiogenesis, gap-junctional communication and cell proliferation, appeared to be decreased in follicles from the penultimate compared to the final wave of an estrous cycle, when the lifespan of follicles from the penultimate wave was extended such that they were present in the ovary with follicles from the final wave of the cycle.
228

Étude de la fonction ovarienne chez les souris déficientes des enzymes hyaluronidases

Dumaresq-Doiron, Karine 08 1900 (has links)
Les mammifères femelles naissent avec un très grand nombre de follicules ovariens primordiaux (104-106); par contre, la grande majorité (99%) de ces follicules n’atteignent jamais la maturité et subissent l’atrésie, principalement par l’apoptose des cellules de la granulosa. Notre laboratoire a démontré que les hyaluronidases des mammifères induisent l’apoptose des cellules de la granulosa et sont impliquées dans l’atrésie des follicules mais que cet effet apoptotique ne serait pas dû à leur activité enzymatique. Notre modèle propose que les hyaluronidases aient un rôle dans les follicules non destinés à ovuler. Le but de la présente étude est d’évaluer la folliculogénèse et la fertilité des souris déficientes de ces enzymes. Les résultats montrent que la délétion de Hyal-3 ne semble pas affecter la fonction ovarienne des souris mais qu’il pourrait y avoir un effet compensatoire par Hyal-1 chez les souris déficientes de Hyal-3 étant donné que son expression est augmentée chez ces souris. La délétion de Hyal-1 a pour effet d’augmenter le nombre des follicules primordiaux, primaires et secondaires, particulièrement chez les souris de bas âge, et de diminuer le niveau d’apoptose des cellules de la granulosa. Afin d’évaluer la fonction de Hyal-1, -2 et -3 sans effet compensatoire entre elles, nous avons voulu créer une souris déficiente des ces 3 hyaluronidases spécifiquement dans les gonades en utilisant le système Cre/loxP. Un vecteur contenant la séquence Cre sous le contrôle du promoteur de Inhibin-α, qui conduit l’expression des gènes en aval chez les cellules somatiques des gonades, a été construit avec succès. En conclusion, cette étude nous révèle que Hyal-3 ne semble pas affecter la fonction ovarienne mais que la délétion de Hyal-1 augmente la folliculogénèse et diminue l’apoptose des cellules de la granulosa. / Female mammals are born with a large number of ovarian primordial follicles, though the vast majority of these never reach the preovulatory stage and undergo atresia, mainly through granulosa cell apoptosis. Our laboratory has established that mammalian hyaluronidases induce apoptosis of ovarian granulosa cells and that they are involved in follicular atresia but that their apoptotic effect is not due to their enzymatic activity. Our model suggests that mammalian hyaluronidases might have a role in follicles not destined to ovulate. The aim of this study was to evaluate the folliculogenesis and fertility of mice devoid of these enzymes. Our results showed that Hyal-3 KO mice have normal folliculogenesis, which could be explained by a compensatory effect of Hyal-1 since its expression is upregulated in these mice. In contrast, Hyal-1 KO mice had increased numbers of primordial, primary and secondary follicles, particularly in young mice, and lower levels of granulosa cell apoptosis. In order to investigate the effect of the three hyaluronidases, Hyal-1, -2 and -3, without a compensatory effect by one another, we decided to create a transgenic mouse deficient in all these three hyaluronidases but only in the gonads by using the Cre/loxP system. We successfully created a plasmid containing the Cre sequence under the control of Inhibin-α promoter, which conducts gene expression in somatic cells of the gonads. In conclusion, the present work demonstrates that Hyal-3 does not have any effect on ovarian function, but that deletion of Hyal-1 in mice promotes increased folliculogenesis and lowers granulosa cell apoptosis.
229

Estudo de hormônios sexuais em células foliculares de tireoide humana em cultura primária

Santin, Ana Paula January 2012 (has links)
Os mecanismos etiopatogênicos que levam ao desenvolvimento dos nódulos e tumores da tireoide ainda não são bem conhecidos. É fato estabelecido que a prevalência dessas lesões é maior nas mulheres. Dessa forma, o que nos motivou a realizar esta Tese foi avaliar se os hormônios sexuais femininos tem efeito direto sobre as células de tireoide humanas normais podendo contribuir para a sua etiopatogenia. Este estudo teve como objetivos padronizar um modelo de cultura primária de células foliculares de tireoide humana normal e nesse modelo validar um gene normalizador após tratamento com estradiol e progesterona, avaliar os efeitos da progesterona na expressão dos genes NIS, TG e TPO bem como avaliar a expressão gênica e proteíca e a possível localização intracelular do receptor de membrana GPR30 nestas células. Em nosso modelo de cultura primária em monocamada, as células foliculares mantiveram sua morfologia cubóide característica e permaneceram diferenciadas o que foi evidenciado pela dosagem de tireoglobulina e T4 livre, no sobrenadante do meio de cultura, e pela identificação das proteínas TG e TPO por imunocitoquímica. A estimulação com progesterona aumentou a expressão dos genes NIS, TG e TPO, respectivamente, 1.78 (p=0.003), 1.50 (p=0.034) e 1.64 (p=0.018) vezes, quando comparadas ao grupo tratado somente com TSH. Essa estimulação da progesterona foi inibida por mifepristona sugerindo que a progesterona tem efeito direto nas células foliculares da tireoide e que esse efeito é mediado por seu receptor nuclear. A normalização da expressão gênica foi realizada pelo gene β-actina, o qual demonstrou uma maior estabilidade entre os grupos analisados. Demonstramos também que as células normais da tireoide expressam tanto o gene como a proteína do receptor de membrana GPR30 com possível localização na membrana celular e no espaço perinuclear. / The mechanisms leading to the development of thyroid nodules and tumors are not well established. As these lesions are more common in women, female sex hormones could be involved in the pathogenesis of these disorders. The objectives of this study were to establish a model of primary culture of normal human thyroid follicular cells, to validate a normalizing gene for qRT-PCR after treatment with estradiol and progesterone, to evaluate the effects of progesterone on the expression of genes NIS, TG and TPO, and to evaluate the GPR30 gene and protein expression as well as its possible intracellular location, in these cells. In our model of primary monolayer culture, follicular cells maintained their characteristic cuboid differentiated morphology; and had evidence of differentiated thyroid function: the production of thyroglobulin and free T4, and identification of TG and TPO proteins by immunocytochemistry . Adding progesterone to TSH increased NIS, TG and TPO mRNA, respectively, 1.78 (p=0.003), 1.50 (p=0.034) and 1.64 (p=0.018) folds, compared to the group treated with only TSH. This stimulation was inhibited by mifepristone, suggesting that progesterone has a direct effect on the thyroid follicular cells. Normalization of gene expression was performed using β-actin as reference gene. We have also demonstrated that normal thyroid cells expressed GPR30 gene and protein, which is possibly localized in the plasma membrane and the perinuclear region.
230

Utilização de células foliculares ovarianas para o aprimoramento de técnicas de reprodução assistida e para a compreensão da falência ovariana precoce

Alcoba, Diego Duarte January 2016 (has links)
A infertilidade é uma condição clínica que acomete até 15% dos casais em idade reprodutiva. Como forma de tratamento para essa parcela da população a Medicina Reprodutiva dispõe de várias técnicas de Reprodução Assistida que visam auxiliar o casal na obtenção da gestação. O primeiro passo para obtenção de sucesso na Medicina Reprodutiva é o correto diagnóstico da infertilidade e, do ponto de vista didático, as causas de infertilidade podem ser classificadas em: feminina, masculina, mista ou desconhecida. A causa feminina de infertilidade apresenta como importante fator o ovariano, representado, principalmente, por alterações no processo de maturação do oócito e/ou no processo de foliculogênese. Com relação à maturação do oócito, um dos possíveis tratamentos oferecidos pela Medicina Reprodutiva é a aplicação da técnica de maturação in vitro (MIV). Infelizmente a MIV não apresenta resultados animadores, e um dos motivos é a falta de um método adequado de seleção dos gametas de humanos que podem ser destinados à ela. No entanto, várias técnicas de seleção de oóticos já foram descritas para espécies animais; dentre elas destaca-se a coloração dos complexos cumuli-oócitos com o corante Azul Cresil Brilhante (BCB). A sua aplicação na espécie humana permanece com ressalvas, uma vez que a comunidade científica preocupa-se com os possíveis efeitos tóxicos dessa substância. Nesta Tese, conseguimos demonstrar, através da avaliação de ensaios de viabilidade e de proliferação celular, e da expressão gênica e proteica, a inocuidade dessa substância para o modelo de cultura primária de células foliculares ovarianas luteinizadas, indicando que o protocolo de coloração com BCB é seguro para a espécie humana. Adicionalmente, conseguimos caracterizar e padronizar o cultivo dessas células, que são amplamente utilizadas em estudos na área da Medicina Reprodutiva. Com relação ao outro fator ovariano de infertilidade (o processo de foliculogênese), sabe-se que a depleção acelerada dos folículos ovarianos pode provocar falência ovariana precoce (FOP), uma condição clínica que acomete até 1% das mulheres em idade reprodutiva e leva à infertilidade. Uma das causas da FOP é a alteração no gene Fragile X Mental Retardation 1 (FMR1) e consequentemente em sua proteína (FMRP). Muito do conhecimento do controle dessa proteína provem de experimentos em neurônios, onde o seu controle já foi elucidado. Nesta Tese, conseguimos demonstrar que o controle dessa proteína nas células ovarianas de humanos é similar ao controle que ocorre nos neurônios, envolvendo a via de sinalização S6K. / Infertility is a clinical condition that affects up to 15% of couples of reproductive age. Reproductive medicine applies many assisted reproductive technologies (ARTs) in order to help them to achieve pregnancy. The first step for infertility treatment success is the correct infertility diagnosis, which is divided into four categories: female, male, mixed or unknown. Female infertility is chiefly represented by ovarian dysfunctions, which are generally related to oocyte maturation and/or folliculogenesis. With regard to oocyte maturation, in vitro oocyte maturation (IVM) is one ART that can be applied but, unfortunately, nowadays it does not present suitable results, since we do not have an effective method of selecting competent human oocytes. On the other hand, in animal reproduction brilliant cresyl blue (BCB) staining has already been described as an appropriate method for oocyte selection. However its clinical applicability to humans is some away off, owing to concerns about its safety. In this thesis we have demonstrated (through many cellular viability and proliferation assays and gene and protein expression), that BCB staining, applying the correct protocol, seems to be safe for use in humans (using the primary culture of human ovarian follicular cells as an experimental model). Additionally, we have characterized and standardized the primary culture of human ovarian follicular cells, and this experimental model is widely applied in reproductive medicine experiments. With regard to folliculogenesis, it is well known that premature ovarian failure/insufficiency (POF/POI) is one condition that can be caused by follicle depletion (when folliculogenesis occurs too fast). This condition affects about 1% of females of reproductive age, causing infertility. Genetic alterations, such as in the fragile X mental retardation 1 (FMR1) gene and its protein FMRP, are considered as one cause of POF/POI. Most of our knowledge about FMRP cellular control comes from studies on neurons, and in these cells we have a clue about its control. In this thesis, we have shown that FMRP control on human granulosa cells is similar to its control on neurons, and this involves the S6K pathway.

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