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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.
321

Morfofisiologia do sistema genital masculino de ratos púberes e adultos após privação androgênica durante a pré-puberdade / Morphophysiology of male reproductive system of adult and pubertal rats after androgen deprivation during prepuberty

Perobelli, Juliana Elaine, 1985- 02 June 2012 (has links)
Orientador: Wilma De Grava Kempinas / Texto em português e inglês / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T10:45:10Z (GMT). No. of bitstreams: 1 Perobelli_JulianaElaine_D.pdf: 9640563 bytes, checksum: dea242a152c4f569490c3cdf5d5010c1 (MD5) Previous issue date: 2012 / Resumo: Os desreguladores endócrinos são agentes químicos capazes de agir como agonistas ou antagonistas dos hormônios endógenos, interferindo na homeostasia do organismo. Como o sistema endócrino tem papel crítico sobre o desenvolvimento e função do sistema genital, este pode ser considerado um alvo particularmente vulnerável a perturbações endócrinas. A literatura apresenta dados sobre a exposição aos antiandrogênicos durante a vida pré-natal e adulta e suas consequências sobre a função reprodutiva de machos. Entretanto, poucos estudos se atentaram para as consequências da privação androgênica durante a pré-puberdade sobre o sistema genital masculino. A pré-puberdade corresponde à fase em que o epidídimo, órgão reprodutor masculino responsável pela maturação e estocagem dos espermatozoides, passa por importantes mudanças morfofuncionais, além de consistir em período de maior susceptibilidade aos desreguladores endócrinos. O objetivo do presente estudo foi avaliar as possíveis consequências da privação de andrógenos durante a pré-puberdade sobre a morfofisiologia do sistema genital masculino de ratos púberes e adultos, com ênfase sobre o epidídimo e qualidade espermática. A escolha por um agente antiandrogênico foi devida à vasta exposição ambiental e ocupacional da população mundial a este grupo de contaminantes. Ratos machos da variedade Wistar foram alocados em: grupo flutamida (25mg/Kg/dia de flutamida, via oral, do dia pós natal 21 ao 44) e controle (óleo de milho, via oral, durante o mesmo período). Os animais foram avaliados aos 50 dias e 75 dias de idade. Foram analisados os níveis séricos dos hormônios sexuais (LH, FSH e testosterona), níveis de testosterona intratesticular, peso de órgãos, histologia testicular e epididimária, imunohistoquímica para marcação de receptor androgênico (AR), proteína espermática 22 (SP22), calmodulina (CALM) e Rab11A em tecido epididimário, além de marcação de CALM e Rab11A no testículo e western blot para AR no epidídimo. Avaliações adicionais foram realizadas nos animais de 75 dias, como comportamento sexual, fertilidade após acasalamento natural e inseminação artificial, motilidade e morfologia espermática, contagens espermáticas nos testículos e epidídimos, análise do perfil proteico de membrana espermática e contagem de células de Sertoli. No grupo tratado com flutamida, os animais púberes apresentaram redução do peso dos órgãos sexuais, relacionado à diminuição na testosterona sérica, além de alteração no padrão de imunomarcação para AR e CALM no epidídimo. Os demais parâmetros foram comparáveis entre os grupos experimentais. Nos animais de 75 dias de idade que receberam flutamida observou-se alteração no padrão de imunomarcação para AR, CALM e Rab11A no epidídimo, diminuição do potencial de fertilidade após inseminação artificial, comprometimento da motilidade espermática, diminuição do número de espermatozoides na cabeça/corpo e cauda do epidídimo, aceleração do trânsito espermático nestas regiões epididimárias e alteração na concentração de CALM e Rab11A na membrana espermática. Os demais parâmetros foram similares entre os grupos experimentais. Os resultados obtidos mostram que a privação de andrógenos durante a pré-puberdade causou alterações na qualidade dos espermatozóides prejudicando o potencial de fertilidade dos indivíduos na idade adulta. Tais resultados parecem estar associados a mudanças no perfil proteico da membrana dos espermatozoides e na expressão de determinadas proteínas no epitélio epididimário, sugerindo que o desenvolvimento pós-natal do epidídimo pode ter sido comprometido, acarretando danos funcionais permanentes ao órgão / Abstract: Endocrine disrupters are chemicals that can act as agonists or antagonists of endogenous hormones, interfering with the homeostasis of the organism. Since the endocrine system plays a critical role in the development and function of the male reproductive system, this is an especially vulnerable target of potential endocrine perturbations. The literature presents data on exposure to antiandrogens during the prenatal life and adulthood and its consequences on the male reproductive function. However, few studies have investigated the possible effects on the male reproductive system of rats after androgen deprivation during prepuberty. The prepubertal period comprehends the phase in which the epididymis, male reproductive organ responsible for the sperm maturation and storage, undergoes significant morphofunctional changes, besides being a period of more vulnerability to endocrine disrupters, possibly due to hormonal imprinting. The aim of this study was to evaluate the possible consequences of androgen deprivation during the prepuberty on morphophysiology of male reproductive system of pubertal and adult rats, focusing on the epididymis and sperm quality. The choice of an antiandrogen agent was due to extensive environmental and occupational exposure of the general population to this group of contaminants. For this purpose, Wistar male rats were divided into flutamide group (flutamide 25mg/Kg/day, orally, from postnatal day 21 to 44) and control group (corn oil, orally, during the same period). The animals were evaluated at 50 days and 75 days of age. At both ages it was evaluated the serum sexual hormone levels, intra-testicular testosterone levels, organ weights, testicular and epididymal histopathology, immunohistochemistry for androgen receptor (AR), sperm protein 22 (SP22), calmodulin (CALM) and Rab11A in epididymal tissue, besides immunostaining for CALM and Rab11A in the testis and Western blot for AR in the epididymis. Furthermore, additional parameters were assessed in 75-day-old animals, such as sexual behavior, fertility after natural mating and after artificial insemination, sperm motility and morphology, sperm counts in the testis and epididymis, proteomic of sperm membrane by bi-dimensional electrophoresis and Sertoli cells counts. Pubertal animals showed reduced reproductive organs weight, probably due to a decrease in serum testosterone and changes in the pattern of immunostaining for AR and CALM in the epididymis. The other parameters were comparable between the groups. In animals at 75 days old changes in the pattern of immunostaining for AR, CALM and Rab11A in the epididymis, decreased fertility potential after artificial insemination, impaired sperm motility, decrease in the sperm numbers in the caput/corpus and cauda epididymis, acceleration of sperm transit time through these epididymal regions, and modifications in three proteins of sperm membrane were observed. Other parameters were similar between the groups. The results show that androgen deprivation during prepuberty impairs sperm quality affecting the fertility potential of the animals at adulthood. These results seem to be related to the changes in protein profile of sperm membrane and protein expression in the epididymis, suggesting that the postnatal development of the epididymis may have been compromised, causing permanent damage to the organ function / Doutorado / Biologia Celular / Doutor em Biologia Celular e Estrutural
322

Altération de la dynamique des canalicules biliaires in vitro : une nouvelle approche de la prédiction de la cholestase intrahépatique d'origine médicamenteuse / Alterations of bile canaliculi dynamics : a new approach in the prediction of drug-induced intrahepatic cholestasis

Burbank, Matthew 06 December 2016 (has links)
La cholestase intrahépatique est une manifestation fréquente des lésions hépatiques induites par les médicaments; Cependant, les mécanismes impliqués sont peu connus. Nous avons cherché à étudier les mécanismes de la cholestase induite par les médicaments afin d’améliorer sa détection précoce en utilisant les cellules HepaRG humaines. Tout d'abord, nous avons prouvé que les canalicules biliaires (BC) subissaient des contractions spontanées, essentielles pour l'efflux d’acides biliaires et nécessitaient des séries d’alternance dans la phosphorylation/déphosphorylation de la chaîne légère de myosine (MLC2). La courte exposition à des composés cholestatiques a révélé que la modulation des BC était associée à des perturbations de la voie de signalisation ROCK/MLCK. Afin de confirmer notre étude, 12 médicaments cholestatiques et six non cholestatiques ont été analysés et nous avons démontré que tous les médicaments cholestatiques classés sur la base de résultats cliniques provoquaient des perturbations dans la dynamique des BC (dilatation ou constriction), et altéraient la voie de signalisation ROCK/MLCK, tandis que les composés non cholestatiques n'avaient pas d'effet. Nous avons également prouvé que ces changements étaient plus spécifiques que la mesure de l'inhibition de l’efflux comme marqueurs prédictifs non cliniques de la cholestase induite par les médicaments. Afin de confirmer et d’étendre ces conclusions, nous avons analysé les mécanismes impliqués dans les effets cytotoxiques et cholestatiques induits par 4 médicaments de la famille des antagonistes des récepteurs de l'endothéline: deux ayant un lien avec des cas cliniques d'hépatotoxicité (sitaxentan) et/ou cholestase (bosentan), et deux n’ayant pas été impliqués dans l’élévation de transaminases hépatiques ou de bilirubine (ambrisentan et macitentan). Les résultats montrent que le macitentan récemment commercialisé et ayant une structure chimique similaire à celle du bosentan, était capable de causer, comme ce dernier, des altérations in vitro des BC. En revanche, l'ambrisentan n’était pas hépatotoxique et le sitaxentan qui a été retiré du marché pour des cas d’hépatotoxicité, n’affectait pas la dynamique canaliculaire. / Intrahepatic cholestasis represents a frequent manifestation of drug-induced liver injuries; however, the mechanisms involved in such injuries are poorly understood. We aimed to investigate mechanisms underlying drug-induced cholestasis and improve its early detection using human HepaRG cells. First, we proved that bile canaliculi (BC) underwent spontaneous contractions, which are essential for bile acid efflux and required alternations in myosin light chain (MLC2) phosphorylation/dephosphorylation. A short exposure to cholestatic compounds revealed that BC dynamics was altered and associated with impairment of the ROCK/MLCK pathway. Then, in order to confirm our study, 12 cholestatic drugs and six noncholestatic drugs were analyzed and we demonstrated that all cholestatic drugs classified on the basis of reported clinical findings caused disturbances of both BC dynamics (dilatation or constriction), and alteration of the ROCK/MLCK signaling pathway, whereas noncholestatic compounds had no effect. We also proved that these changes were more specific than efflux inhibition measurements alone as predictive nonclinical markers of drug-induced cholestasis. To confirm and extend these conclusions, we analyzed the mechanisms involved in cytotoxic and cholestatic effects induced by the 4 main drugs from the endothelin receptor antagonists family: two related to clinical cases of hepatotoxicity (sitaxentan) and/or cholestasis (bosentan), and two that have not been reported to cause elevation of liver transaminases or bilirubin (ambrisentan and macitentan). The results showed that like bosentan, the structurally similar recently marketed drug, macitentan, could cause in vitro major BC alterations. By contrast, ambrisentan appeared as a safe drug and sitaxentan that has been withdrawn from the market for hepatotoxic cases, did not impair BC dynamics.
323

Profiling Populations Using Neutral Markers, Major Histocompatibility Complex Genes and Volatile Organic Compounds as Modeled in Equus caballus Linnaeus

Deshpande, Ketaki 03 October 2016 (has links)
Assessing the genetics of wild animal populations aims to understand selective pressures, and factors whether it be inbreeding or adaptation, that affect the genome. Although numerous techniques are available for assessing population structure, a major obstacle in studying wild populations is obtaining samples from the animals without having to capture them, which can lead to undue distress and injury. Therefore, biologists often use non-invasive sampling methods (i.e., collection of feces, hair) to extract host DNA. In this study, new DNA extraction protocols were developed that improved the quality and quantity of DNA obtained from fecal matter. Fecal samples aged up to Day 6 as well as field samples with unknown days since defecation were successful in individualization of the contributors using microsatellites and were further used to demonstrate kinship. Neutral markers such as short tandem repeat, and mitochondrial D-loop sequences are used for assessing relatedness and evolutionary relationships and can mutate without detrimental effects on the organism. Loci, such as the major histocompatibility complex (MHC), adapt more rapidly under selective pressure such as parasite load, or resistance to diseases and support natural selection processes. Analysis of the neutral microsatellites in Big Summit feral horse population demonstrated a population lacking diversity and trending towards being an inbred population. However, examination of the MHC genes showed maintenance of greater variation that may be the result of selection pressures. The MHC similarity and lower genetic demarcation between geographically separated horse populations further indicated effect of selection pressures in preserving diversity at the MHC genes. Although such molecular markers are used in profiling populations, the current study was also successful in demonstrating the use of individual odor profiles as an additional profiling tool. Volatile organic compounds (VOC) obtained from hair of domestic horses were able to individualize horses as well as differentiate between horse breeds and display kinship. The relation of genetics to odor phenotype is of interest as the inherent polymorphic nature of MHC genes has the potential to generate unique combinations of genotypes that presumably produce distinct odor phenotypes. Subsequently, this study was able to show a significant correlation between MHC genotypes and VOC odor profiles in horses. Understanding the relationship between MHC and odor using domestic horses with known relatedness provides evidence that these same correlations may be applicable to wild equids and dictates their harem hierarchal social structure.
324

Inhalational cough challenges in the assessment of cough

Khalid, Saifudin January 2013 (has links)
Introduction: Cough is the commonest reason for which medical advice is sought. In assessment of chronic cough and in developing anti-tussive medications, inhalational cough challenges with capsaicin and citric acid are commonly employed. However the ability of these inhalational cough challenges to distinguish health and disease is not clear and it is not known which end point is best in making such assessments. Methods: Subjects belonging to five different categories (healthy volunteers, subjects with COPD, asthma, healthy current smokers and chronic cough) were compared with each another by using the standard cough challenges employing Capsaicin and Citric acid and also by using newer inhalational cough challenge agents such as prostaglandin E2 and bradykinin. In addition adaptation to repeated inhalations of tussive agents was also assessed. The relationship between the cough reflex sensitivity as gauged by using inhalational cough challenge tests and objective cough recording was explored in all five groups. Finally the change in C5 in Capsaicin evoked cough by using a substance to block TRPV1 channel and its effect on objective cough recording was assessed in subjects with chronic cough. Results: Different tussive agents have different abilities to distinguish between different diagnostic categories and a combination of inhalational cough challenge tests have a better accuracy of predicting diagnostic groups as compared to one on its own. There are significant differences in the rates of adaptation to repeated inhalations of PGE2 and there is a significant reduction in cough response over period of time in all disease groups. Using the TRPV1 antagonist resulted in a modest increase in the Log C5 concentration of capsaicin but this was not matched by a change in objective cough recording or CQLQ scores. Conclusions: The different abilities of tussive agents to distinguish between different diagnostic categories suggest that the information conveyed by the one inhalational cough challenge test is different from that by another test. The choice of the inhalational cough challenge test should therefore depend on which groups are included in the study. There was no significant difference in the rate of adaptation to prolonged challenge with citric acid or capsaicin and no significant correlation of the magnitude of adaptation with objective cough recording suggesting that this is unlikely to be responsible for the increased cough rates seen in diseases such as chronic cough, COPD or asthma. The TRPV1 antagonist did not result in a significant change in objective cough recording or CQLQ scores. The change in C5 with the TRPV1 antagonist was however modest and this may be reason for this study failing to show a relationship between these different measures.
325

Recherche de biomarqueurs des cellules propagatrices de glioblastome : étude de la signalisation calcique et du protéome membranaire / Research for glioblastoma cancer stern cel!s biomarkers : calcium signaling and membrane proteome studies

Audran, Emilie 21 September 2012 (has links)
Les glioblastomes sont des tumeurs au pronostic défavorable. L’échec des thérapies est lié à la présence de cellules souches cancéreuses (CSCs), résistantes aux traitements ; la caractérisation de ces cellules et l’identification de biomarqueurs sont donc primordiales. Le calcium contrôle de nombreux processus cellulaires ; parmi les éléments majeurs de la signalisation calcique, la Calmoduline (CaM) est impliquée dans différentes pathologies, dont des cancers, et est un puissant régulateur de l’état physiologique d’une cellule. CaM interagit avec de nombreuses protéines impliquées dans la régulation de l’homéostasie calcique de la cellule. Nous avons cherché à identifier et caractériser des antagonistes de CaM, inhibant différentiellement ces interactions. L’utilisation de ces antagonistes en tant que perturbateurs de l’homéostasie calcique a permis de mettre en évidence un marqueur caractérisé des CSCs de glioblastomes. D’autre part, l’étude comparée du protéome membranaire de CSCs issues de glioblastomes a permis de mettre en évidence la surexpression de clusters de différenciation et protéines impliquées dans la signalisation calcique. Ces protéines sont de potentiels marqueurs moléculaires des CSCs de glioblastome. / Glioblastomas are malignant tumor of poor prognosis. Therapeutic failure might be supported by cancer stem cells (CSCs); characterization of these cells and biomarkers identification are of most importance. Calcium controls numerous cellular process; beyond major elements of calcium signaling, Calmodulin (CaM) is involved in different pathologies and tumors, and is a powerful regulator of cell physiological state. CaM interacts with a plethora of proteins involved in cell calcium homeostasis regulation. We aimed at identifying and characterizing CaM antagonists, capable of differentially inhibiting these interactions. The use of these antagonists in calcium homeostasis disturbance led to the identification of a characterized marker of glioblastomas CSCs. In another approach, the comparative study of glioblastomas CSCs membrane proteome uncovered the overexpression of differentiation clusters and proteins involved in calcium signaling. These proteins are potential molecular biomarkers for glioblastomes CSCs.
326

Espessura íntima-média carotídea em pacientes com câncer de próstata em tratamento antiandrogênico / Carotid intima-media thickness in patients with prostate cancer receiving androgen-deprivation therapy

Soares, William Giovanni Panfiglio 18 July 2014 (has links)
Introduction: Prostate cancer is the most common malignancy in Brazilian males and androgen deprivation therapy (ADT) is generally employed in its treatment. However, ADT is associated with negative outcomes, like increased incidence of obesity, insulin resistance, diabetes, dyslipidemia and cardiovascular diseases. Many of these side effects are closely related to atherosclerosis. Carotid intima-media thickness (CIMT) is an important biomarker of atherosclerosis, and is employed as risk predictor for cardiovascular and cerebrovascular disease. Objectives: The study aimed to analyze the carotid intima-media thickness in patients with prostate cancer, inspect for the presence of plaque in their carotid arteries, and investigate the relationship between carotid plaques with ADT duration and cardiovascular risk factors. Methods: A cross-sectional study of 65 men diagnosed with prostate cancer undergoing ADT for, at least three months, was conducted from July to November 2013. Patients were matched for age, comorbidities, treatment type, duration and stage of the neoplasm. The presence of plaque was defined as a focal structure that encroaches into the arterial lumen of at least 0.5 mm or 50% of the surrounding intima-media thickness value or demonstrates a thickness >1.5. Results: Seventy participants were enrolled, but five were excluded due to incomplete data collection. The mean age (±SD) was 73.9 (±9.4) years, 34% were receiving maximum androgen blockade (peripheral and central associated) and patients were under ADT for 34.8 (±31.5) months. The LDL-c, HDL-c and triglycerides had values outside the normal range in 26%, 65% and 48% patients, respectively. Thirty-nine (60%) patients had carotid plaques. The average thickness of the carotid intima-media in patients without plaques was 1.24 (±0.18) mm. Statistically significant relationship between the intima-media thickness and age, diastolic blood pressure and body mass index (BMI) was found (p = 0.002; p = 0.015 and p = 0.007, respectively). About the laboratory tests, statistical significance was found between atherosclerosis in this population and SHBG (sex hormone-binding globulin) and quantitative CRP (C-reactive protein), p = 0.033 and p = 0.011, respectively. Patients under maximum androgen blockade had significantly higher risk for the presence of carotid plaques in comparison to patients under exclusive central androgen blockage (p = 0.01). Conclusion: Among the 65 men tested, the average thickness of the carotid intima-media was 1.24 mm. Carotid-artery plaque was present in 60% of the individuals, although no statistical significance was found between the presence of carotid plaques and duration of androgen treatment. On the other hand, a significant relationship between CIMT and age, BMI, diastolic blood pressure, maximum androgen blockade, SHBG and CRP was observed, that should be considered for risk-benefit discussion related to ADT and future studies. / Introdução: O câncer de próstata é a neoplasia maligna mais comum no homem brasileiro e o tratamento antiandrogênico (TAA) é frequentemente utilizado. No entanto, seu uso está relacionado a uma série de efeitos adversos, como obesidade, resistência à insulina, diabetes mellitus, dislipidemia e doenças cardiovasculares. Muitos desses efeitos colaterais guardam relação bem estabelecida com o processo de aterosclerose. A espessura íntima-média carotídea (EIMC) é um importante marcador diagnóstico de aterosclerose subclínica e é utilizada como preditor de risco para doença cardiovascular (DCV) e cerebrovascular. Objetivos: Analisar a EIMC em pacientes portadores de câncer de próstata, verificar a presença de placas nas artérias carótidas, relacionar a presença de placas carotídeas à duração do TAA e aos fatores de risco de DCV. Casuística e métodos: Estudo transversal envolvendo 65 homens com diagnóstico de câncer de próstata em TAA há pelo menos três meses, no período de julho a novembro de 2013. Os pacientes foram pareados por idade, comorbidades, tipo de tratamento, duração e estágio da neoplasia. Considerou-se como placa uma alteração focal que se projeta para a luz arterial em pelo menos 0,5 mm ou 50% do valor adjacente da EIMC, ou uma medida da EIMC > 1,5 mm. Resultados: Setenta pacientes foram entrevistados, porém cinco foram excluídos por desistência. A média da idade foi de 73,9 (±9,4) anos, 34% recebiam bloqueio androgênico combinado (castração associada a bloqueio periférico) e os pacientes encontravam-se em média há 34,8 (±31,5) meses sob TAA. O LDL-c, o HDL-c e os triglicerídeos apresentaram valores fora da normalidade em 26%, 65% e 48% dos pacientes, respectivamente. Trinta e nove (60%) pacientes apresentaram placas carotídeas. A espessura média da íntima-média carotídea nos pacientes sem placas foi de 1,24 (±0,18) mm. Foi encontrada significância estatística, quanto à presença de espessamento médio-intimal com relação à idade, à pressão arterial diastólica (PAD) e ao índice de massa corpórea (IMC), com p=0,002; p=0,015 e p=0,007, respectivamente. Quanto aos exames laboratoriais, houve significância estatística entre a presença de aterosclerose e os valores encontrados na análise sérica de SHBG (globulina transportadora de hormônio sexual) e PCR (proteína C reativa) quantitativa, com p=0,033 e p=0,011, respectivamente. Os pacientes em uso de bloqueio hormonal combinado apresentaram significativamente maior risco para placas carotídeas que os pacientes em castração exclusiva (p=0,01). Conclusão: Dentre os 65 homens analisados, a espessura média da íntima-média carotídea foi de 1,24 mm. Foi observada presença de placas nas artérias carótidas de 60% da amostra, porém não foi encontrada significância estatística entre a presença de placas carotídeas e a duração do tratamento antiandrogênico. Por outro lado encontrou-se relação significativa entre EIMC e idade, IMC, PAD, bloqueio androgênico combinado, SHBG e PCR, que devem ser levados em consideração na discussão do risco-benefício do TAA e em futuros estudos.
327

Effets des modulateurs du récepteur de la progestérone dans des modèles de cancer mammaire humain / Effects of Progesterone Receptor Modulators in Human Breast Cancer Models

Esber, Nathalie 21 October 2015 (has links)
Le rôle des progestatifs et du récepteur de la progestérone (PR) dans la carcinogénèse mammaire est maintenant établi. Le PR est exprimé sous deux isoformes PRA et PRB dont l'expression est équimolaire mais qui différent par leur activité transcriptionnelle des gènes cibles. La surexpression de PRA est associée à un pronostic défavorable du cancer mammaire, et est observée chez les femmes à haut risque génétique de cancer du sein. L'utilisation d'antagonistes pour inhiber l'activité de PR pourrait constituer une stratégie thérapeutique potentielle. L'objectif de cette thèse a été d'évaluer les effets de l'ulipristal acétate (UPA), un anti-progestatif, sur la tumorigenèse mammaire dans deux modèles d'études complémentaires. In vitro, dans la lignée cancéreuse mammaire bi-inductible (MDA-iPRAB) développée au laboratoire. Nous avons démontré qu'UPA inhibe la prolifération cellulaire induite par la progestérone en présence de PRA. L'expression de certains gènes clés de la tumorigenèse mammaire, cibles de PRA a été étudiée. Une corrélation entre avec la prolifération cellulaire et l'expression du facteur anti-apoptotique BCL2-L1 (messager et protéine) a été démontrée. L'activation transcriptionnelle, dépendante de la progestérone et inhibée par l'UPA, s'accompagne d'un recrutement spécifique et sélectif de PRA sur des séquences régulatrices du gène BCL2-L1, comme le démontrent les expériences de ChIP. In vivo, nous avons évalué l'efficacité anti-tumorale de l'UPA ainsi qu'une nouvelle classe d'antagoniste sélective et passive de PR, les « APRns » dans un modèle murin de xénogreffe de tumeur mammaire humaine HBCx34. UPA ralentit la croissance tumorale, diminue la prolifération cellulaire (Ki67, PCNA) et inhibe l'expression de BCL2-L1. L'ensemble de nos résultats démontrent une action antiproliférative et apoptotique de l'UPA ce qui suggère une utilisation potentielle d'antagonistes de PR dans la prise en charge du cancer du sein. / The role of progestins and the progesterone receptor (PR) in breast tumorigenesis has now been elucidated. PR is expressed as two isoforms PRA and PRB, differing by their structure and their transcriptional activity. They are often co-expressed in normal breast tissue but the predominance of PRA expression is associated with mammary carcinogenesis, a bad prognosis and an endocrine-resistance. Antiprogestins inhibit mammary tumor growth in several experimental models. The aim of this thesis was to investigate the effect of a well-known selective PR modulator (SPRM), Ulipristal acetate (UPA) in two complementary breast cancer models. In vitro, we used the newly established bi-inducible breast cancer cell line “MDA-iPRAB”, and demonstrated an anti-proliferative activity of UPA in progesterone-dependent, PRA-specific MDA-iPRAB cell proliferation. We also studied the expression of PRA-target genes involved in mammary tumorigenesis, and showed a correlation between cell proliferation and the expression of the anti-apoptotic factor BCL2-L1 (transcript and protein). The transcriptional activation of BCL2-L1 was stimulated by the progesterone in MDA-iPRA cell line, inhibited by UPA and was associated with a specific and selective recruitment of PRA to BCL2-L1 regulatory regions (ChIP assays). In vivo, we evaluated the anti-tumoral activity of UPA and a new class of selective and passive progesterone receptor antagonist ‘APRns' in patient-derived breast cancer xenograft in nude mice. UPA slowed down mammary tumor growth, decreased cell proliferation (Ki67, PCNA) and inhibited the BCL2-L1 expression. Further investigation are needed to determine the actions of APRns. In summary, UPA has an antiproliferative and a pro-apoptotic activities, which suggests a potential interest of UPA in breast cancer endocrine therapy.
328

THE EFFECTS OF ESTROGEN-INDUCED STROMAL CELL EFFECTORS, OSTEOPONTIN AND VIMENTIN, ON CHLAMYDIA INFECTIONS IN A NON-POLARIZED CELL CULTURE MODEL

Bowers, Hannah Elizabeth, Hall, Jennifer 04 April 2018 (has links)
Chlamydia is the most reported sexually transmitted infection in the US and is caused by the obligate intracellular bacterium Chlamydia trachomatis. Typically, this presents as a lower genital tract infection (cervicitis or urethritis), but can ascend to the upper genital tract, causing pelvic inflammatory disease, tubal infertility, epididymitis, or ectopic pregnancy. While chlamydia infections can be cured with a single-dose oral antibiotic, repeat infections are common and having multiple chlamydial infections increases a woman’s risk of developing serious chronic conditions. Previous research has shown that estrogen has a positive effect on C. trachomatis infections—an important finding, connecting fluctuating estrogen levels in females to variance in pathogenesis.The mechanism behind this hormonal influence remains unknown; however, previous work in our laboratory indicates that estrogen-stimulated stromal cell effectors play a role in enhancing C. trachomatis infections in a polarized endometrial epithelial Ishikawa (IK)/stromal (SHT-290) cell co-culture model. Specifically, our data indicate that estrogen exposure stimulates osteopontin and vimentin release from stromal cells in co-culture with endometrial epithelial cells. Furthermore, we noted that Chlamydia-infected, polarized Ishikawa cells exposed to a combination of recombinant osteopontin and estrogen released significantly more infectious chlamydia than cultures exposed to estrogen alone. Most tissue culture models being used today employee non-polarized cells. Given the fact that epithelial cell polarization is known to impact C. trachomatis serovar E development, in the current study we sought to determine if the estrogen-induced stromal cell effectors, osteopontin and vimentin, affect C. trachomatis viability and infectivity in non-polarized Ishikawa cells. Non-polarized Ishikawa cells were exposed to osteopontin or vimentin in the presence or absence of estrogen, infected with C. trachomatis serovar E, and collected for examination of chlamydial infectivity and progeny production. Our initial data show that osteopontin and vimentin impact chlamydial progeny production in a concentration dependent fashion, with higher concentrations of recombinant effectors +/- estrogen significantly decreasing progeny production. These data suggest that polarization of host cells influences the way hormone-stimulated effectors interact with the cell to impact on chlamydial infection. Future research goals are to explore other stromal effectors such as fibronectin with estrogen and to study the cell signaling mechanism osteopontin and vimentin use to affect chlamydial infections in polarized epithelial cell cultures.
329

The Stimulation of Luteinizing Hormone Secretion from Anterior Pituitary Cells in Culture by Substance P: A Dissertation

Shamgochian, Maureen 01 May 1990 (has links)
The observations that substance P (SP) is localized in the anterior pituitary gland (AP) and is regulated by the hormonal status of the animal, as well as the demonstration of SP binding sites in the AP, have led to the idea that SP may participate in the regulation of AP function. Numerous and sometimes contradictory reports of SP effects on AP hormone secretion, particularly on luteinizing hormone (LH), left the question of whether SP acts directly at the level of the AP to regulate LH secretion still unanswered. To investigate a possible physiological function of SP in the AP, the effects of exogenous SP on LH secretion from AP cells from adult and prepubertal male and female rats in short term culture were studied. It was found that SP (100nM-1μM) significantly stimulates LH release in cultured AP cells and that this effect varies as a function of age and sex. SP has no significant effect on LH release from AP cells of male and female prepubertal rats. After day 30 a sharp increase in the response to SP occurs in both sexes. This level of responsiveness continues through adulthood in AP cells from the female rat. In contrast, AP cells from male rats failed to respond during adulthood (over 50 days of age) but were highly responsive during the peripubertal period (30-35 days). The possibility that the responsiveness to SP is influenced by the endocrine status of the animal was investigated by exposing AP cells from responding animals to androgens in vivo and in vitro. It was found that AP cells from female rats treated with androgen were less responsive to 100nM SP but did respond at higher doses of SP. SP effects on AP function were further analyzed in experiments using radioligand binding assays to assess possible changes in SP receptor number or affinity as related to age and sex. In AP membranes from female rats, maximum binding is 8-fold higher (Bmax=4.2 pmo1/mg membrane protein) than in AP membranes from male rats (Bmax=560fmo1/ mg membrane protein). These studies suggest a role for SP as a secondary regulator of LH secretion with possible physiological significance for reproductive function.
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PERIPHERALLY RESTRICTED OPIOID CONJUGATES AND ITS USE AS PHARMACOLOGICAL PROBES AND POTENTIAL THERAPEUTICS

Tuhin, Md Tariqul Haque 01 January 2022 (has links)
Opioid-induced constipation (OIC) is one of the major adverse effects of opioid analgesics used by millions of patients each year. While progress has been made, there remains a significant unmet medical need in the treatment of OIC. Major gaps remain in our understanding of the role of the gastrointestinal tract and central nervous system (CNS) in precipitating OIC. For the last four decades, numerous investigations to study the sites of action of opioid analgesics have utilized peripherally acting mu-opioid receptor antagonists (PAMORAs), which have been incorrectly believed to have limited penetration across the blood-brain barrier (BBB). Several preclinical and clinical reports indicate that significant amounts of PAMORAs penetrate the BBB quite readily. As a result, the usage of current PAMORAs have resulted in misunderstandings of the role of the CNS and gastrointestinal tract in causing side effects such as opioid-induced constipation (OIC). We have developed a transthyretin-based novel drug delivery approach for restricting the passage of small molecules across the BBB. Our approach involves endowing the opioid agonist/antagonist with the selective transthyretin ligand, AG10. The newly synthesized naloxone- and oxycodone-based conjugates have demonstrated superior peripheral selectivity, improved pharmacokinetics, and efficacy in rats compared to other clinically used PAMORAs. Here we present chemical synthesis, in vitro binding and stability studies, as well as pharmacokinetic and pharmacodynamic evaluations of the AG10-opioid conjugates in rats. Our AG10-based PAMORA allowed us to obtain new insights into the important role of mu-opioid receptors in the central nervous system (CNS) in causing constipation. Additionally, our results demonstrate for the first time that synergy between mu-opioid receptors in the central nervous system and the gastrointestinal tract is crucial to the understanding of OIC and the development of effective treatment regimens. These findings contradict prior ideas that OIC was caused by a mechanism that involves primarily the gastrointestinal mu-opioid receptors. Moreover, we confirmed our findings by a AG10-oxycodone conjugate, a peripherally restricted opioid agonist. This molecule demonstrated the predominant role of CNS in OIC precipitation. The newly synthesized AG10-opioid conjugates represent a novel class of pharmacological probes that will aid in our understanding of OIC and other undesirable adverse effects of opioids. In addition, these conjugates have been evaluated for their potential therapeutic value in the preclinical studies. Collectively our approach to limit the BBB penetration of opioids will contribute to develop safer and more effective opioid medications.

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