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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

An Evaluation of the Effects of a Novel Estrogen, Progesterone, and Melatonin Hormone Therapy on Mammary Cancer Development, Progression and Uterine Protection in the MMTV-Neu Mouse Model

Dodda, Balasunder 15 June 2015 (has links)
Estrogen therapy (ET) is most effective to reduce menopausal symptoms and prevent other disorders associated with estrogen deficiency. However, Women's Health Initiative studies found that hormone therapy (HT) containing estrogen plus progestogen, but not estrogen-alone increases breast cancer (BC) risk. To prevent the increase in BC risk and yet relieve menopausal symptoms, a novel HT with 17β-estradiol (E2) for symptom relief, progesterone (P4) for uterine protection and melatonin (Mel) for both BC and uterine protection was designed. Inclusion of Mel was postulated to offer uterine protection with lower P4 dose and protect against BC. The goal of this study was to assess the efficacy of E2, P4 and Mel Therapy (EPMT) on mammary cancer (MC) and uterine protection in MMTV-Neu mouse model that mimics HER2 BC. Starting at 2 months age, female mice received Mel in drinking water at night to supplement endogenous Mel surge; while E2 and P4 Therapy (EPT) was provided continuously in diet until 14 months with weekly MC onset and growth monitoring. Normal mammary, uterus and mammary tumors harvested by month 14 were analyzed for potential mechanisms. The results from this study revealed that EPMT delayed tumor onset leading to a decrease in MC incidence. In addition, mice in the EPMT group had no increase in relative uterine weight as opposite to an increase of this parameter in EPT group versus control. The percent tumor-bearing mice with gross metastatic lung lesions were reduced in Mel, EPT and EPMT groups. Mel receptor, estrogen receptor (ER) and progesterone receptor (PR) expression revealed that all tissues examined have Mel receptors. However, ER and PR expression varied. In normal mammary tissue, both ERα and PR were detected by immunohistochemistry. However, no ERα and PR were detected in mammary tumors of same mice. In uterus, mice given Mel or EPMT had significant decreases in PR expression but no change in ERα expression compared to control suggesting that Mel-mediated inhibition of ER binding to estrogen response elements may be involved in the down regulation of uterine PRs. Overall, this study reveal that EPMT prevents mammary cancer and may protect against uterotrophy. / Mylan School of Pharmacy and the Graduate School of Pharmaceutical Sciences; / Pharmacology / PhD; / Dissertation;
2

An Evaluation of the Effects of a Novel Estrogen, Progesterone, and Melatonin Hormone Therapy on Mammary Cancer Development, Progression and Uterine Protection in the MMTV-Neu Mouse Model

Dodda, Balasunder 16 April 2015 (has links)
Estrogen therapy (ET) is most effective to reduce menopausal symptoms and prevent other disorders associated with estrogen deficiency. However, Women's Health Initiative studies found that hormone therapy (HT) containing estrogen plus progestogen, but not estrogen-alone increases breast cancer (BC) risk. To prevent the increase in BC risk and yet relieve menopausal symptoms, a novel HT with 17β-estradiol (E2) for symptom relief, progesterone (P4) for uterine protection and melatonin (Mel) for both BC and uterine protection was designed. Inclusion of Mel was postulated to offer uterine protection with lower P4 dose and protect against BC. The goal of this study was to assess the efficacy of E2, P4 and Mel Therapy (EPMT) on mammary cancer (MC) and uterine protection in MMTV-Neu mouse model that mimics HER2 BC. Starting at 2 months age, female mice received Mel in drinking water at night to supplement endogenous Mel surge; while E2 and P4 Therapy (EPT) was provided continuously in diet until 14 months with weekly MC onset and growth monitoring. Normal mammary, uterus and mammary tumors harvested by month 14 were analyzed for potential mechanisms. The results from this study revealed that EPMT delayed tumor onset leading to a decrease in MC incidence. In addition, mice in the EPMT group had no increase in relative uterine weight as opposite to an increase of this parameter in EPT group versus control. The percent tumor-bearing mice with gross metastatic lung lesions were reduced in Mel, EPT and EPMT groups. Mel receptor, estrogen receptor (ER) and progesterone receptor (PR) expression revealed that all tissues examined have Mel receptors. However, ER and PR expression varied. In normal mammary tissue, both ERα and PR were detected by immunohistochemistry. However, no ERα and PR were detected in mammary tumors of same mice. In uterus, mice given Mel or EPMT had significant decreases in PR expression but no change in ERα expression compared to control suggesting that Mel-mediated inhibition of ER binding to estrogen response elements may be involved in the down regulation of uterine PRs. Overall, this study reveal that EPMT prevents mammary cancer and may protect against uterotrophy. / Mylan School of Pharmacy and the Graduate School of Pharmaceutical Sciences; / Pharmacology / PhD; / Dissertation;
3

Exposição da próstata de fêmeas de gerbilo da Mongólia (Meriones unguiculatus) a doses ambientais de Bisfenol A e 17beta estradiol /

Bedolo, Carolina Marques January 2020 (has links)
Orientador: Sebastião Roberto Taboga / Resumo: A próstata é uma glândula componente do sistema genital dos mamíferos e sua principal função prostática é secretar um fluido levemente alcalino (pH 7,29) que contribui para a formação do líquido seminal. As fêmeas em certas espécies, como o roedor gerbilo da Mongólia (Meriones unguiculatus), apresentam próstata cuja morfologia se assemelha à porção ventral do complexo prostático masculino e à próstata feminina em humanos. Nas últimas décadas tem sido relatado um constante aumento da exposição a substâncias capazes de interferir na ação hormonal, conhecidas como disruptores endócrinos. O bisfenol A (BPA) pertence a uma das categorias de disruptores endócrinos presentes no meio ambiente. Estudos demonstram que a exposição a esse composto interfere negativamente na morfofisiologia prostática, favorecendo o estabelecimento de lesões pré-malignas e malignas. Além do BPA, uma das constantes problemáticas dos dias atuais é a exposição ambiental a hormônios exógenos como o estradiol (E2). Desta forma, a administração de fármacos com estrutura semelhante a hormônios esteroides pode exercer efeitos sobre a glândula, uma vez que os mesmos se ligam a seus receptores hormonais afetando a homeostasia prostática. O presente estudo teve como objetivo verificar as alterações morfofuncionais na próstata de fêmeas de gerbilo da Mongólia após tratamento perinatal com dose diária ambiental, ou seja, dose ambiental segura de BPA (50 µg/kg) e doses de 17-β estradiol (35 µg/kg), 3 vezes por semana p... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre
4

Effects of Long-Term Exposure of Normal C57BL/6J Inbred Mice to 17β-Estradiol on Gene Expression in Lymphocytes: mRNA Analysis of Lymphokines and bcl-2/fas

Yin, Zhi-Jun 18 August 1997 (has links)
It is now clear that human and animal exposure to estrogenic compound occurs through several sources. This include: i) naturally occurring endogenous estrogens, ii) exogenous or intentional estrogens for prophylactic (e.g. oral contraceptive) and therapeutic (e.g. as replacement therapy for ovulation in nulliparous women and in menopausal women, and in some men suffering from prostate cancer) purposes, iii) accidental via estrogenic chemical exposure (e.g. pesticides, industrial byproducts) and phytoestrogens (e.g. soybeans). It has long been recognized that estrogen, a female sex hormone, functions not only on the reproductive system, but also on various other systems including the immune system. Estrogens are thought to be of both physiologic and pathologic importance. Female in general, have better immune capabilities than males, a phenomenon attributed to the action of sex hormones on the immune system. There is also a female-gender bias in susceptibility to autoimmune diseases. Estrogens have been linked either directly or indirectly to the etiology and pathogenesis of various female-predominant autoimmune diseases. Estrogens have also been linked to the onset of cancer, and conditions where the immune system often malfunctions. Estrogen affects the functions of both B and T cells, possibly by regulating such factors as lymphokine gene expression and/or cellular death by apoptosis. However, the functioning of both B and T cells under the influence of long-term exposure to estrogen has not been fully understood. The primary aim of this thesis was to investigate the effect of long-term exposure to 17β-estradiol on lymphokine and bcl-2/fas (proto-oncogenes) mRNA expression. We evaluated the effects of estrogen on the expression of genes for lymphokines, which are essential for the immune response. It is hypothesized that estrogen may regulate the immune system by modifying the expression of lymphokine genes and/or genes that regulate apoptosis. The results demonstrated that long-term 17β-estradiol exposure reduced the viability of lymphocytes when compared to lymphocytes from placebo-treated mice. IL-2 and IFN-g mRNA was consistently higher in ConA-stimulated lymphocytes from estrogen-treated mice (P < 0.05). The mRNA for TGF-β₁ lymphokine was also increased but was not consistent at all time points of incubation. The expression of IL-4 mRNA was not noticeably affected by estrogen treatment of mice. Long-term exposure to 17β-estradiol appear to have some influence on the mRNA expression of proto-oncogenes fas and bcl-2 in splenic and thymic T lymphocytes. There was a trend of increased bcl-2 mRNA expression in estrogen-treated mice compared to placebo-treated mice, whereas the mRNA expression of fas gene appeared to be lower compared to controls. Overall, these findings suggest that 17β-estradiol may selectively influence lymphokine and proto-oncogene mRNA expression. These results suggest that the one mode of modulation of the immune response by 17β-estradiol may be through alterations in the lymphokine and proto-oncogene expression. Since estrogen-treatment markedly induces atrophy of the thymus and diminishes the cellularity of the lymphoid organs (e.g. Spleen), it became necessary to perform multiple assays on the same cells, particularly lymphokine and apoptosis gene expression. A secondary objective of this thesis was to investigate whether lymphocytes, which have undergone proliferation in Lympho-Pro™ assay (Alamar Blue assay), could be utilized for further analysis. In this regard, we found that a non-radioactive assay that utilizes Alamar Blue had significant advantages over the conventional ³H-thymidine incorporation assay. By using cells from estrogen and placebo-treated mice in the Alamar Blue assay, we found that this assay not only allowed determination of lymphocyte proliferation, but also the assessment of mRNA expression, cytogenetics, apoptosis and immunophenotyping of the same lymphocytes. / Master of Science
5

Reproduction de l'huître perlière Pinctada margaritifera : étude des déterminants du sexe femelle chez l'adulte / Reproduction of the pearl oyster Pinctada margaritifera : study of the female sex determinants in adult oyster

Teaniniuraitemoana, Vaihiti 08 December 2014 (has links)
Depuis plusieurs années il est devenu essentiel de comprendre le déterminisme sexuel des espèces à fort intérêt économique afin d’optimiser leur production au sein d’écloseries émergentes.L’objectif principal de cette thèse était de mettre en évidence les mécanismes impliqués dans la détermination et la différenciation sexuelle, et notamment du sexe femelle, chez l’huître perlière P. margaritifera, espèce hermaphrodite protandre et espèce clé de la perliculture, la seconde ressource économique pour la Polynésie française. Pour atteindre cet objectif, deux approches ont été menées : une approche transcriptomique visant à étudier les mécanismes moléculaires du déterminisme et de la différenciation sexuelle, et une approche expérimentale visant à comprendre le phénomène de la sexualisation par des forçages environnementaux et hormonaux en s’intéressant plus particulièrement au déterminisme et à la différenciation sexuelle femelle.Dans l’approche transcriptomique, le transcriptome de la gonade de P. margaritifera a été séquencé à partir de plusieurs échantillons gonadiques d’huîtres de sexe mâle et femelle à différents stades de développement. Après le séquençage Illumina et l'assemblage du transcriptome, 70 147 contigs ont été obtenus. L’analyse fonctionnelle de ces 70 147contigs, a permis d’identifier des gènes d’intérêt et ainsi de constituer un catalogue de 87 ARNm codant pour 67 protéines impliquées dans la détermination, la différenciation sexuelle et/ou la gamétogenèse. Ensuite une analyse stricte des données de quantification RNAseq a révélé 1 937 contigs exprimés de manière différentielle entre les catégories histologiques des gonades. À partir de l’analyse de leurs profils d’expression au sein de chaque échantillon, un nouveau modèle de la reproduction de P. margaritifera, basé sur une double approche analytique, eg. histo-moléculaire, a été proposé. Ce modèle révèle notamment que le déterminisme sexuel de P. margaritifera chez l’adulte se produirait durant une phase de régression de la gonade. Considérant ainsi les nouveaux stades définis par ce modèle, 9 gènes biomarqueurs de la voie sexuelle femelle ont pu être identifiés révélant un modèle prédictif de la voie sexuelle basé sur 3 rapports d’expressions de gènes impliquant 2 gènes inconnus pmarg-c43476 et pmarg-c54338 et 2 gènes connus pmarg-foxl2 et pmarg-fem1-like. Ce deuxième modèle suggère fortement l'implication de pmarg-foxl2 et pmarg-fem1-like dans le déterminisme du sexe de P. margaritifera. Dans l’approche expérimentale, deux expérimentations séparées ont été réalisées pour mettre en évidence l’effet i) de plusieurs combinaisons de température et de niveau trophique, et ii) de l’œstradiol-17β administré par injection directe dans la gonade ; sur le sexe, la gamétogenèse et l’expression des neuf gènes biomarqueurs de la voie sexuelle femelle identifiés précédemment. Les résultats ont montré que la condition combinant la température de 28°C et la concentration en algues de 40 000 cellules mL-1 était la plus favorable non seulement à la maturation des gonades mâles et femelles mais aussi au maintien du sexe femelle. Ce serait dans cette condition environnementale qu’il serait possible d’induire un changement de sexe de mâle vers femelle. Dans la seconde expérimentation, il a été clairement démontré que la reproduction de P. margaritifera pouvait être régulée par les hormones œstrogènes. Les résultats montrent un effet négatif de l’œstradiol sur le développement et la différenciation mâle. Enfin les résultats du modèle prédictif de la voie sexuelle de P. margaritifera, suggèrent une programmation génétique du sexe femelle qui toutefois resterait soumise aux conditions environnementales validant ainsi l’hypothèse d’un mode de détermination mixte du sexe chez P. margaritifera. / For several years it has become essential to understand sex determination of species with high economic interest to maximize their production in emerging hatcheries.The main objective of this thesis was to identify the mechanisms involved in sex determination and sex differentiation, and particularly in female sex, in the pearl oyster P. margaritifera, a protandrous hermaphrodite species and the key species of the pearl farming, the second economic resource for French Polynesia. To achieve this goal, two approaches were undertaken: a transcriptomic approach to investigate the molecular mechanisms of sex determinism and sex differentiation, and an experimental approach to understand the phenomenon of sexualization by environmental and hormonal forcing focusing especially on female sex determinism and female sex differentiation.In the transcriptomic approach, the gonad transcriptome of P. margaritifera was sequenced from several samples of male and female oyster gonads at different stages of development. After Illumina sequencing and assembly of the transcriptome, 70,147 contigs were obtained. Functional analysis of these 70,147 contigs identified genes of interest and allowed the constitution of a catalog of 87 mRNAs encoding 67 proteins involved in sex determination, sex differentiation and/or gametogenesis. Then a strict analysis of RNAseq quantification data revealed 1,937 contigs differentially expressed between the histological categories of gonad. From the analysis of their expression profiles in each sample, a new model of reproduction of P. margaritifera, based on dual analytical approach, i.e. histo-molecular, has been proposed. This model shows that sex determination of adult P. margaritifera pearl oysters occur during a regression phase of the gonad. And considering the new stages defined on this model, 9 biomarkers genes of the female sexual pathway have been identified revealing a 3-gene-pair expression ratio based model, which makes it possible to predict the sexual pathway in this hermaphrodite species. This predictive model involves two unknown genes pmarg-c43476 and pmarg-c54338 and 2 known genes pmarg-foxl2 and pmarg-fem1-like, and strongly suggests the involvement of pmarg-foxl2 and pmarg-fem1-like in sex determinism in P. margaritifera.In the experimental approach, two separated experiments were conducted to demonstrate the effect of i) various combinations of temperature and trophic level, and ii) 17β-estradiol administered by direct injection into the gonad; on sex, gametogenesis and expression of the nine biomarkers genes of the female sexual pathway previously identified. The results showed that the condition combining a temperature of 28 °C and a concentration of 40 000 cells of algae mL-1 was the most favorable not only for the maturation of the male and female gonads but also for the maintenance of the female sex. It would be in this environmental condition that it would be possible to induce a sex change from male to female. In the second experiment, it was clearly demonstrated that the reproduction of P. margaritifera could be regulated by estrogen hormones. The results show a negative effect of estradiol on male development and differentiation. Finally the results of the predictive model of the sexual pathway of P. margaritifera, suggest a genetic programming of the female sex, which however remain subject to environmental conditions, thus validating the hypothesis of a mixed sex determinism mode in P. margaritifera.
6

A Study of the fate and transport of estrogenic hormones in dairy effluent applied to pasture soils

Steiner, Laure D. January 2009 (has links)
The disposal of waste from agricultural activities has been recognised as a source of environmental contamination by endocrine disrupting chemicals (EDCs). The New Zealand dairy industry produces a large volume of dairy farm effluent, which contains EDCs in the form of estrogens. Most of this dairy farm effluent is applied onto the land for disposal. Groundwater and soil contamination by estrogens following waste application on the land have been reported overseas, but our understanding of the processes and factors governing the fate of estrogens in the soil is poor. Therefore the main goal of the present study was to better understand the fate and transport of estrogens, in particular 17β-estradiol (E2) and estrone (E1) in soil. In order to quantify E1 and E2 in drainage water and soil samples, chemical analysis by gas-chromatography mass-spectrometry (GC-MS) was carried out. This included sample extraction, sample clean-up through silica gel and gel permeation chromatography, and sample extract derivatisation prior to analysis. In order to develop a reliable method to extract estrogens from soil, research was conducted to optimise E1 and E2 extraction conditions by adjusting the number of sonication and shaking events, as well as the volume and type of solvent. Among five solvents and solvent mixtures tested, the best recovery on spiked and aged soil was obtained using an isopropanol/water (1:1) mix. A microcosm experiment was carried out to determine the dissipation rates of E2 and E1, at 8°C and at field capacity, in the Templeton soil sampled at two different depths (5-10 cm and 30-35 cm). The dissipation rates decreased with time and half-life values of 0.6-0.8 d for E1 and 0.3-0.4 d for E2 were found for the two depths studied. A field transport experiment was also carried out in winter, over three months, by applying dairy farm effluent spiked with estrogens onto undisturbed Templeton soil lysimeters (50 cm in diameter and 70 cm deep). The hormones were applied in dairy farm effluent at 120 mg m⁻² for E2 and 137 mg m⁻² for E1. The results of the transport experiment showed that in the presence of preferential/macropore flow pathways 0.3-0.7% of E2 and 8-13% of E1 was recovered in the leachate at the bottom of the lysimeters after 3 months, and 1-7% of the recovered E2 and 3-54% of the recovered E1 was leached within 2 days of application. These results suggest that leaching of estrogens via preferential/macropore flow pathways is the greatest concern for groundwater contamination. In the absence of preferential/macropore flow pathways, a significant amount (> 99.94%) of both hormones dissipated in the top 70 cm of soil, due to sorption and rapid biodegradation. Surprisingly, in all cases, estrogen breakthrough occurred before that of an inert tracer (bromide). This could not be explained by the advection-dispersion transport of estrogens, nor by their presence as antecedent concentrations in the soil. It was therefore suggested that colloidal enhanced transport of estrogens was responsible for the earlier breakthrough of estrogens and caused the leaching of a fraction of the applied estrogens to a soil depth of 70 cm. A two-phase model, adapted from a state-space mixing cell model, was built to describe the observed estrogen transport processes under transient flow. The model takes into account 3 transport processes namely, advection-dispersion, preferential/macropore flow and colloidal enhanced transport. This model was able to successfully describe the estrogen transport observed from the lysimeters.
7

The effect of hypoxia on ER-β expression in the lung and cultured pulmonary artery endothelial cells

Selej, Mona M.A. 12 March 2014 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / 17-β estradiol (E2) exerts protective effects in hypoxia-induced pulmonary hypertension (HPH) via endothelial cell estrogen receptor (ER)-dependent mechanisms. However, the effects of hypoxia on ER expression in the pulmonary-right ventricle (RV) axis remain unknown. Based on previous data suggesting a role of ER-β in mediating E2 protection, we hypothesized that hypoxia selectively up-regulates ER-β in the lung and pulmonary endothelial cells. In our Male Sprague-Dawley rat model, chronic hypoxia exposure (10% FiO2) resulted in a robust HPH phenotype associated with significant increases in ER- β but not ER-α protein in the lung via western blotting. More importantly, this hypoxia-induced ER-β increase was not replicated in the RV, left ventricle (LV) or in the liver. Hence, hypoxia-induced ER-β up-regulation appears to be lung-specific. Ex vivo, hypoxia exposure time-dependently up-regulated ER-β but not ER-α in cultured primary rat pulmonary artery endothelial cells (RPAECs) exposed to hypoxia (1% O2) for 4, 24 or 72h. Furthermore, the hypoxia induced ER-β protein abundance, while not accompanied by increases in its own transcript, was associated with ER-β nuclear translocation, suggesting increase in activity as well as post-transcriptional up-regulation of ER-β. Indeed, the requirement for ER-β activation was indicated in hypoxic ER-βKO mice where administration of E2 failed to inhibit hypoxia-induced pro-proliferative ERK1/2 signaling. Interestingly, HIF-1α accumulation was noted in lung tissue of hypoxic ER-βKO mice; consistent with previously reported negative feedback of ER-β on HIF-1α protein and transcriptional activation. In RAPECs, HIF-1 stabilization and overexpression did not replicate the effects of ER- β up-regulation seen in gas hypoxia; suggestive that HIF-1α is not sufficient for ER-β up- regulation. Similarly, HIF-1 inhibition with chetomin did not result in ER-β down-regulation. HIF-1α knockdown in RPAECs in hypoxic conditions is currently being investigated. Hypoxia increases ER- β, but not ER-α in the lung and lung vascular cells. Interpreted in context of beneficial effects of E2 on hypoxic PA and RV remodeling, our data suggest a protective role for ER-β in HPH. The mechanisms by which hypoxia increases ER-β appears to be post-transcriptional and HIF-1α independent. Elucidating hypoxia-related ER-β signaling pathways in PAECs may reveal novel therapeutic targets in HPH.

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