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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.
1

The effects of RU486, used as a postcoital contraceptive, on the rat uterus during early pregnancy

Theron, Kathrine Elizabeth 09 March 2011 (has links)
PhD,School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand / Tissue specific regulation of the progesterone receptor is central to female health. The synthetic steroid, RU486 is a partial progesterone and oestrogen receptor antagonist, functioning to actively silence progesterone receptor gene associated transcription. For this reason, it has been used both as a contraceptive and quite controversially as an abortive agent. In this study, both cellular and gene specific effects of RU486 were investigated in a rat model of early pregnancy, this including the key phases of the plasma membrane transformation, the window of receptivity and early implantation. As all of these stages are hormonally regulated by progesterone and oestrogen, the focus here was to elucidate the mechanisms of action of a single dose of RU486, used as a postcoital contraceptive, at day 3.0 of pregnancy, to successfully prevent implantation of a viable blastocyst and subsequent pregnancy. In association with the cellular preparation of uterine epithelial cells for implantation, selected molecular targets and events were investigated at a protein and gene expression level, both prior to and after RU486 treatment, to assess the effects of either a deficit or excessive expression of these gene products on uterine preparation and eventual implantation. Factors here included the progesterone receptor, markers of apoptosis (Bax and Bcl2), mediators of angiogenesis (VEGF, bFGF and PDGF) and biomarkers of endometrial implantation (LIF, Calcitonin and Muc-1). Together, an ultrastructural and light microscopy analysis showed RU486 to morphologically alter the uterine endometrial cells and to disrupt the plasma membrane transformation of early pregnancy, predisposing these cells towards apoptosis. In association with this, progesterone receptor gene and protein expression was ubiquitously decreased throughout pregnancy. With regards to the implantation process of early pregnancy, the luminal epithelial cells undergo apoptosis to allow the hatching blastocyst to penetrate and implant within the uterine wall. This is partially mediated by the ratio of the expression of the apoptotic factors Bax and Bcl-2. Surprisingly here, RU486 caused an overall anti-apoptotic environment, despite previously observed high levels of apoptotic activity. This indicates that factors other than Bax and Bcl-2 influence the RU486-induced apoptosis. A crucial event of early pregnancy is the establishment of an adequate blood supply to sustain and nourish the implanting blastocyst. There was a decided reduction in the angiogenic response of early pregnancy, as a direct consequence of RU486 treatment; the normally high levels of VEGF and bFGF during early pregnancy, were markedly decreased at all three days of pregnancy. This was reflected in the lack of increased vascularisation as normally signalled by the indicator dye, Pontamine Sky blue. In contrast to the overall increase in VEGF and bFGF at the time of blastocyst implantation during early pregnancy, increased PDGF expression was localised to the implantation sites, strongly suggesting a role for this angiogenic factor in endothelial cell proliferation. v The endometrial biomarkers are indicative of implantation, their expression patterns varying around the phase of implantation. These markers are essential to implantation, as when LIF and Calcitonin are deregulated and Muc-1 persists on the apical surface of the endometrium, implantation fails. These events are precisely what occur following RU486 treatment. In summary, the overall effects of RU486 in the rat model of early pregnancy, when used as a postcoital contraceptive, indicate highly effective inhibition of progesterone and oestrogen effects on the endometrium, mediated by their receptors. More specifically, the structural and molecular events mirror those described in ovariectomised animal models, suggesting a hormonally under-stimulated endometrium. Clearly from the present study, the precise priming of the endometrium in preparation for blastocyst implantation is severely impaired by RU486 through a number of signalling pathways, thus predisposing the uterus to pregnancy failure.
2

Infant-directed behaviour in the naturally paternal male dwarf hamster, Phodopus campbelli, is neither activationally nor organizationally regulated by activity at the progesterone receptor

THORPE, JOELLE 04 September 2009 (has links)
Phodopus campbelli is a naturally biparental dwarf hamster with males so paternal they will act as midwives during the birth of their litter. The hormonal regulation of parental behaviour has been well established in many species. However, to date, no causal mechanism for the extensive paternal behaviour displayed by male P. campbelli has been discovered. Recently, activity at the progesterone receptor has been shown to inhibit infant-directed behaviour in male mice. Therefore, the first study in this thesis was carried out to determine if antagonism of the progesterone receptor (PR) would enhance infant-directed care behaviour in naïve P. campbelli males. Despite detectable serum progesterone concentration in males, PR antagonism did not alter progesterone concentration, nor did it alter infant-directed behaviour in males with antagonized PR in adulthood. A slight increase in the latency to retrieve a pup seen in males with antagonized PR during adolescence suggests that there may be a developmental effect of PR activity on infant-directed behaviour in adulthood. Neonatal male rats express high levels of PR in brain regions important for parental behaviour. Since hormones can act very early in life to organize adult behaviour, the second study was carried out to determine if progesterone acting much earlier than adolescence is important in the regulation of paternal behaviour in P. campbelli adulthood. Males were treated daily for the first week of life with transdermal progesterone, which increased neonatal serum progesterone concentration fivefold. Despite the significant increase in progesterone (and therefore presumably activity at the PR), male behaviour in three different stages of adulthood (sexually naïve, during the birth of the male’s first litter, and in new fatherhood) towards pups was not altered. Measures of paternal contribution such as pup weight throughout the lactational period were altered by progesterone treatment during the neonatal period, but litter quality was ultimately high in both groups. Therefore, activity at the PR in adulthood, puberty, or during the neonatal period does not inhibit paternal behaviour in the naturally biparental hamster, P. campbelli. Thus, progesterone and its receptor do not organizationally or activationally regulate paternal behaviour in P. campbelli. / Thesis (Master, Biology) -- Queen's University, 2009-09-04 13:23:18.733
3

New Mechanisms of Transcriptional Regulation of the Folate Receptor and other genes by steroid Receptors

Shatnawi, Aymen Ahmad January 2007 (has links)
No description available.
4

台灣RU486的生命政治 / The Biopolitics of RU486 in Taiwan

蔡佳蓉, Tsai, Chia Jung Unknown Date (has links)
本論文從傅柯(M. Foucault)的生命政治(biopolitics)觀點,指出口服墮胎藥物RU486之治理體系建構,如何延續了台灣近代從家庭計畫、《優生保健法》立法以來的生命政治(biopolitics)脈絡,卻又因台灣1990年代民主化政治的發展,而不以過去集權政治的方式,反而透過社會行動者之間的互動與角逐形塑而成。台灣近代的人口治理自家庭計畫至《優生保健法》立法時期,執政當局都是秉持著同樣的整體人口治理觀,傳播人口控制與經濟發展扣連的論述,使治理體系越加周延與激進徹底。到了RU486時期,集權的治理已不在,但在對人口進行整體調節,與對肉體進行個體規訓的生命權力(bio-power)論述,仍滲透在行動者的論述中,不斷地擴散與再製,並使得人民被形塑出治理性(governmentality)。RU486治理體系中的臨床規訓實作,即使仍有模糊、不合法的使用不斷地挑戰治理體系的界線,但又透過生命政治體系來回不斷的建構而逐漸被收編至體系內,成為體系的一環。在RU486合法化過程積極參與的女權團體,其興起與集權政治的退場密不可分,同樣積極參與的醫生團體則是透過不斷地與執政當局合作,而發展出其專業自主權,而成為產科領域的唯一專業代言人。RU486因此做為一種整體人口治理的人工流產技術物,其體系之形塑卻因不同社會行動者的積極介入,而在整體調節之餘也部份地彰顯了行動者的自主性,形成了與家庭計畫、《優生保健法》時期的節育與墮胎技術不同的屬性。 / From Michel Foucault’s perspectives on biopolitics, this article explains how the construction of governance system of abortion pill RU486 path-depends on the biopolitics contexts of the family planning and Genetic Health Act. Due to the political democratization during the 1990s in Taiwan, this construction is not shaped by the authority before, but through the interaction and competition of social actors. In Taiwan, the population governance from the family planning to Genetic Health Act in recent years keeps the same population control values, diffusing discourses about the connection of population control and economic developments, and then makes the whole governance system more integral and radical. To the period of RU486 legalization there is no more authority, but bio-power discourses upon overall regulation of population and individual disciplinary of body still infiltrate into the discourse of actors, shaping the governmentality of people. The clinical practices of RU486, though the fuzzy, illegal practices of RU486 still challenge the boundary of governance, are incorporated in a part of the system through the dynamic construction of biopolitics. The rise of feminist organizations that deeply participate in the process of RU486 legalization, is a result of disappearance of authority. Doctor groups, which also participate in the process of RU486 legalization, rise and develop their professional autonomy through the continuous cooperation with the government, becoming the only spokesperson of Obstetrics. We could say that RU486 is a kind of abortion artifact for population governance; apart from the overall regulation in the process of shaping RU486’s governance system, the actors’ autonomy is manifest. As a result, RU486 obtains a different property with the contraception and abortion technologies in the periods of the family planning and Genetic Health Act.
5

Characterization of Myometrial Cytokine Expression and Leukocyte Infiltration During Term and Preterm Labour in the Mouse

Nedd-Roderique, Tamara 15 December 2011 (has links)
Studies indicate an association between both term labour (TL) and preterm labour (PTL) and the presence of uterine inflammatory cytokines and leukocyte infiltration. We hypothesized that peripheral leukocytes are recruited to uterine tissues by locally produced cytokines where they contribute to the initiation of TL and PTL. The cytokine expression profile was analyzed using an in vivo mouse model of gestation and two PTL models (Lipopolysaccharide- and RU486-induced). Myometrial neutrophil and macrophage infiltration was also studied. My results demonstrate that macrophage infiltration precedes neutrophil infiltration during late gestation and that both leukocyte subsets increase during PTL and further increase post partum. These changes in leukocyte numbers are associated with significant changes in multiple myometrial cytokines with TL and RU486-induced PTL showing similar cytokine profiles. Importantly, post partum involution, the process by which the uterus completes the reproductive cycle and returns to its pre-pregnant state, appears similar in all three models.
6

Characterization of Myometrial Cytokine Expression and Leukocyte Infiltration During Term and Preterm Labour in the Mouse

Nedd-Roderique, Tamara 15 December 2011 (has links)
Studies indicate an association between both term labour (TL) and preterm labour (PTL) and the presence of uterine inflammatory cytokines and leukocyte infiltration. We hypothesized that peripheral leukocytes are recruited to uterine tissues by locally produced cytokines where they contribute to the initiation of TL and PTL. The cytokine expression profile was analyzed using an in vivo mouse model of gestation and two PTL models (Lipopolysaccharide- and RU486-induced). Myometrial neutrophil and macrophage infiltration was also studied. My results demonstrate that macrophage infiltration precedes neutrophil infiltration during late gestation and that both leukocyte subsets increase during PTL and further increase post partum. These changes in leukocyte numbers are associated with significant changes in multiple myometrial cytokines with TL and RU486-induced PTL showing similar cytokine profiles. Importantly, post partum involution, the process by which the uterus completes the reproductive cycle and returns to its pre-pregnant state, appears similar in all three models.
7

The Role of Corticosterone in Stress-induced Suppression of Innate Immunity in the Male House Sparrow

January 2017 (has links)
abstract: In wild birds, the stress response can inhibit the activity of the innate immune system, which serves as the first line of defense against pathogens. By elucidating the mechanisms which regulate the interaction between stress and innate immunity, researchers may be able to predict when birds experience increased susceptibility to infections and can target specific mediators to mitigate stress-induced suppression of innate immune activity. Such elucidation is especially important for urban birds, such as the House Sparrow (Passer domesticus), because these birds experience higher pathogen prevalence and transmission when compared to birds in rural regions. I investigated the role of corticosterone (CORT) in stress-induced suppression of two measures of innate immune activity (complement- and natural antibody-mediated activity) in male House Sparrows. Corticosterone, the primary avian glucocorticoid, is elevated during the stress response and high levels of this hormone induce effects through the activation of cytosolic and membrane-bound glucocorticoid receptors (GR). My results demonstrate that CORT is necessary and sufficient for stress-induced suppression of complement-mediated activity, and that this relationship is consistent between years. Corticosterone, however, does not inhibit complement-mediated activity through cytosolic GR, and additional research is needed to confirm the involvement of membrane-bound GR. The role of CORT in stress-induced inhibition of natural antibody-mediated activity, however, remains puzzling. Stress-induced elevation of CORT can suppress natural antibody-mediated activity through the activation of cytosolic GR, but the necessity of this mechanism varies inter-annually. In other words, both CORT-dependent and CORT-independent mechanisms may inhibit natural antibody-mediated activity during stress in certain years, but the causes of this inter-annual variation are not known. Previous studies have indicated that changes in the pathogen environment or food availability can alter regulation of innate immunity, but further research is needed to test these hypotheses. Overall, my dissertation demonstrates that stress inhibits innate immunity through several mechanisms, but environmental pressures may influence this inhibitory relationship. / Dissertation/Thesis / Doctoral Dissertation Biology 2017
8

Implication des axes récepteur des glucocorticoïdes-GILZ et CXCR4-CXCL12 dans l’inflammation hépatique liée à l’obésité / Involvement of glucocorticoid receptor-GILZ and CXCR4-CXCL12 axis in obesity-related liver inflammation

Robert, Olivier 16 December 2014 (has links)
La NAFLD (non alcoholic fatty liver disease) ou stéatopathie dysmétabolique est la manifestation hépatique du syndrome métabolique. Elle regroupe l’ensemble des lésions hépatiques liées à l’obésité en dehors de toute consommation d’alcool : la stéatose, la NASH (non alcoholic steatohepatitis), la fibrose, la cirrhose et le carcinome hépatocellulaire. Les systèmes immunitaires inné et adaptatif participent activement à la pathologie. J’ai étudié deux axes : l’axe du récepteur des glucocorticoïdes-GILZ dans les cellules de Kupffer et CXCR4-CXCL12 dans les lymphocytes T CD4+.Les cellules de Kupffer (CK) jouent un rôle clé dans la pathologie de la NASH. GILZ (glucocorticoid induced leucine zipper) est exprimé par les monocytes/macrophages et est sous le contrôle du récepteur aux glucocorticoïdes (GR). De plus, GILZ intervient dans l’inhibition des processus inflammatoires. J’ai montré que l’obésité entraîne une diminution de l’expression du GR et de GILZ dans les CK. En utilisant du RU486, un antagoniste spécifique du GR, j’ai prouvé que la diminution de l’expression du GR entraîne la diminution de l’expression de GILZ et sensibilise les CK au LPS. Ce mécanisme joue un rôle déterminant dans le développement de l’inflammation hépatique au cours de l’obésité, en modulant la réponse inflammatoire des CK. Le recrutement de cellules inflammatoires dans le foie est un élément clé de la progression de la NASH. Les lymphocytes T CD4+ issus de souris obèses ont des propriétés chimiotactiques accrues dépendantes de CXCR4. J’ai montré que la NASH augmente les propriétés migratoires dépendantes de CXCR4 des lymphocytes T CD4+ chez l’homme et la souris dans trois modèles murins de NASH. Le traitement de souris obèses par de l’AMD3100, un antagoniste de CXCR4, permet de diminuer le recrutement hépatique de lymphocytes. L’augmentation du chimiotactisme des lymphocytes T CD4+ n’était pas dû, ni à une augmentation de l’expression de CXCR4 et CXCR7, ni même de CXCL12 au niveau du foie. J’ai montré que ce mécanisme dépendait de l’augmentation de l’affinité de CXCR4 pour CXCL12.Ainsi, j’ai mis en évidence deux axes participant à l’inflammation hépatique au cours de l’obésité. Ces axes représentent de nouvelles cibles thérapeutiques potentielles. / NAFLD (non alcoholic fatty liver disease) is the hepatic manifestation of metabolic syndrome. It encompasses the entire spectrum of obesity-related liver lesions : steatosis, NASH (non alcoholic steatohepatitis), fibrosis, cirrhosis and hepatocellular carcinoma. Innate and adaptative immune systems participate actively to the pathophysiology.I studied two axis : the glucocorticoid receptor-GILZ axis in Kupffer cells and CXCR4-CXCL12 in CD4+ T lymphocytes.Kupffer cells (KC) play a key role in pathophysiology of NASH. GILZ (glucocorticoid induced leucine zipper) is expressed by monocytes/macrophages and is under the control of glucocorticoid receptor (GR). Moreover, GILZ takes part in inhibition of inflammatory processes. I showed that obesity induces a decreased expression of GR and GILZ in KC. Using RU486, a GR antagonist, I proved that decreased expression of GR induces the decreased expression of GILZ and sensitize KC to LPS. This mechanism plays a decisive role in initiation of liver inflammation in obesity, modulating inflammatory response of KC. In obese mice, recruitment of inflammatory cells into the liver is a key element in the progression of NASH. CD4+ T lymphocytes from obese mice have enhanced CXCR4-dependent chemotactic properties. I showed that NASH enhances CXCR4-dependent chemotactic properties of CD4+ T lymphocytes in patients and in three mouse models of NASH. Obese mice treatment with AMD3100, a CXCR4 antagonist, decreases lymphocytes recruitement into the liver. Enhanced chemotactic properties of CD4+ T lymphocytes were not due to increased expressions of nor CXCR4 and CXCR7, neither CXCL12 in the liver. I showed that this mechanism was dependent of an increased affinity of CXCR4 to CXCL12.Therefore, I highlighted two axis participating to obesity-related liver inflammation. These axis represent new potential therapeutic targets.
9

台灣地區報紙對墮胎新聞報導的內容分析:以《中國時報》、《聯合報》為例

陳靜玟 Unknown Date (has links)
本研究旨在以內容分析方式,分析台灣地區報紙有關墮胎新聞之報導,以瞭解閱聽人所得到的墮胎資訊為何。本研究選定中國時報與聯合報進行分析。分析結果發現台灣地區報紙對於墮胎新聞的報導,多數採用非個案報導,最常出現在墮胎新聞中的主角是未成年未婚者,多數的墮胎新聞是以恐懼手法呈現。對於防治墮胎所需之避孕與正確性教育與兩性關係資訊,台灣報紙在這些方面的報導極度不足。未來應加強此方面的資訊,以有效改善墮胎狀況。
10

Investigating the role of corticosterone in meal anticipatory behaviour, metabolism and glucosetolerance

Namvar, Sara January 2011 (has links)
Daily rhythms in physiology and behaviour are orchestrated by theautonomously rhythmic cells of the suprachiasmatic nucleus (SCN).Restricting food intake to the rest phase of nocturnal rodents, leads to thedevelopment of meal anticipatory behaviour, corticosterone and bodytemperature. Given that lesions to the SCN fail to abolish meal anticipation, asecond oscillator of unknown location, referred to as the food-entrainableoscillator (FEO) is thought to exist. Although the site of the FEO is unknown,several hypothalamus nuclei, including the dorsomedial hypothalamus(DMH) are thought to play a role in meal anticipation. Given thatadrenalectomy is reported to abolish meal anticipation, an intact HPA axis isalso thought to contribute to the functioning of the FEO. Some forms ofobesity are characterised by high basal levels of circulating corticosterone. Inaddition, limited access to high fat diet, fails to induce the development ofrobust meal anticipation in rats. During our initial studies, the effect of a standard and 45% high fat diet onthe development of meal anticipatory behaviour and hypothalamic c-Fosexpression were investigated. Restricted access to high fat diet led toattenuation of meal anticipation compared to those fed standard diet. Thiswas concurrent with a failure to develop an anticipatory rise in DMH c-Fosexpression. A meal anticipatory rise in corticosterone is thought to benecessary for the presence of meal anticipation as well as adaptation ofmetabolism to daily restricted feeding. In the next set of studies, weconfirmed that restricted access to standard diet leads to the development ofa meal anticipatory rise in plasma corticosterone. In contrast we observed adramatic post-anticipatory rise in plasma corticosterone in rats givenrestricted access to the 45% high fat diet. We hypothesised that the highcorticosterone levels resulting from high fat diet were a contributing factor tothe lack of meal anticipation in high fat fed rats. With the aid of apharmacokinetic study, a suitable experiment was designed for daily dosingof a potent glucocorticoid receptor antagonist, RU486, with the aim ofrescuing meal anticipation in high fat fed rats. Interestingly, treatment withRU486 successfully rescued meal anticipation in high fat fed rats, butattenuated meal anticipation in standard diet restricted fed rats. In the finalseries of studies the effect of diet and feeding regime on glucose toleranceand metabolism were investigated. High fat feeding was found to reduceglucose tolerance in both ad lib and restricted fed rats, with RU486 treatmentimproving glucose tolerance in a time dependant manner. Restricted accessto food was found to induce post satiation lipogenesis in both standard dietfed and to a lesser extent in high fat fed rats, an effect which may bebeneficial in reducing obesity. Overall the results provide further insight intothe complex role of corticosterone in promoting or preventing mealanticipatory behaviour. An anticipatory rise in plasma corticosterone isrequired for meal anticipation, as repeated daily dosing of RU486 inhibit mealanticipation. The high basal levels of corticosterone in high fat fed rats mayprevent meal anticipation, insulin secretion and post-satiation lipogenesiswhich may in fact be a homeostatic mechanism to prevent obesity. Nonetheless, treatment with RU486 rescues behavioural meal anticipationand glucose tolerance.

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