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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.
181

The Influence of Steroid Hormones on Tooth Wear in Children and in Adolescents

Buchhardt, Jeanette, Kiess, Wieland, Körner, Antje, Biemann, Ronald, Hirsch, Christian 20 October 2023 (has links)
(1) Background: From a young age, boys are more often affected by tooth wear than girls. This suggests an influence of the male sex hormone (testosterone) on the aetiology of tooth wear. The aim of the present study was to investigate the incidence of tooth wear in relation to steroid hormone levels in children. (2) Methods: 1022 test persons aged between 10 and 18 (491 male, 531 female) from the LIFE Child study underwent medical and dental examination. Tooth wear was measured through clinical inspection. Blood samples were taken to determine hormone levels (testosterone, SHBG). The level of free testosterone was calculated from the ratio of testosterone to SHBG. Using multivariable methods, the incidence of tooth wear was analyzed as a function of hormone levels, while controlling for confounders such as age, sex, social status, and orthodontic treatment. (3) Results: The incidence of tooth wear increased with age in both sexes. Boys showed significantly more often attrition facets than girls (17.5% vs. 13.2%, p < 0.001). Subjects with tooth wear showed significantly higher free testosterone levels than those without (males: p < 0.001, females: p < 0.05). After controlling for confounding variables, the risk of tooth wear increased by approximately 30.0% with each year of life (odds ratio [OR]boys = 1.29, 95% confidence interval [CI] = 1.04–1.56; [OR]girls = 1.32, 95% CI = 1.08–1.61). In addition, the risk of tooth wear increased by 6.0% per free testosterone scale score only in boys (OR = 1.06, 95% CI = 1.01–1.12). (4) Conclusions: Tooth wear is common in children and in adolescents, and it increases steadily with age in both sexes. The stronger increase and the higher prevalence among male adolescents can be explained by the additional effect of free testosterone.
182

Hormonal regulation of cutaneous wound healing: effect of androstenediol on stress impaired wound healing

Head, Cynthia C. 30 August 2007 (has links)
No description available.
183

In Vitro Studies of Adrenocorticolytic DDT Metabolites, with Special Focus on 3-methylsulfonyl-DDE

Asp, Vendela January 2010 (has links)
The DDT metabolite 3-methylsulfonyl-DDE (3-MeSO2-DDE) is bioactivated by cytochrome P450 11B1 (CYP11B1) in the adrenal cortex of mice and forms irreversibly bound protein adducts, reduces glucocorticoid secretion, and induces cell death selectively in cortisol-producing adrenocortical cells. 3-MeSO2-DDE has therefore been proposed as a lead compound for an improved adrenocortical carcinoma (ACC) therapy. The aims of this thesis were to (1) develop in vitro test systems based on murine and human adrenocortical cell lines and to (2) investigate the mechanisms behind 3-MeSO2-DDE toxicity in adrenocortical cells. The cytotoxic and endocrine-modulating effects of 3-MeSO2-DDE were compared to those of o,p′-DDD (mitotane), the current ACC therapy, and to those of several structurally analogous compounds in both murine and human cell lines. 3-MeSO2-DDE bioactivation and cytotoxicity proceeded in a similar manner in the murine adrenocortical Y-1 cell line as in mice in vivo. The effects were highly structure-specific. Moreover, 3-MeSO2-DDE formed irreversibly bound protein adducts and caused cell death also in the human H295R cell line, and was slightly more cytotoxic than o,p′-DDD. However, 3-MeSO2-DDE toxicity in human cells was not affected by the CYP11B1 inhibitor etomidate, suggesting that bioactivation in human cells is performed by additional/other enzyme(s) than CYP11B1. 3-MeSO2-DDE generated biphasic responses in cortisol and aldosterone secretion and in expression levels of the steroidogenic genes CYP11B1, CYP11B2, and StAR. Such hormesis-like responses were not seen for o,p′-DDD or the precursor DDT metabolite p,p′-DDE. In addition, the two o,p′-DDD enantiomers (R)-(+)-o,p′-DDD and (S)-(-)-o,p′-DDD exhibited slight differences in cytotoxic and endocrine-modulating activity in H295R cells. In conclusion, this thesis  provides  extended  knowledge  on  the  mechanisms  of  action  of 3-MeSO2-DDE and points out important differences in effects between murine and human cells. Lead optimisation studies of 3-MeSO2-DDE using the herein presented in vitro test systems are ongoing.
184

Prognostic factors for squamous cell cervical cancer : tumor markers, hormones, smoking, and S-phase fraction

Lindström, Annika January 2010 (has links)
Cervical cancer is the second most common malignancy in women worldwide and one of the leading causes of cancer mortality globally. In patients with invasive cervical cancer prognostic factors are of value for the choice of treatment, monitoring of treatment and follow-up. The most important clinical prognostic factors are stage, tumor volume, parametrial infiltration, vascular invasion, lymph node metastases, and distant metastases. An improved estimation of the prognosis of cervical cancer is desirable, especially in early cancer stages. The aim of this research was to study possible associations between tumor markers, female sex steroids, smoking, S-phase fraction (SPF), and prognosis in invasive squamous cell cervical cancer (SCC). The study comprised 190 patients with SCC, stages IB-IV, admitted to the Department of Gynecologic Oncology at Norrland University Hospital in Umeå between September 1984 and October1990. Ten year mortality was estimated. In study I, of a total of 103 patients, it was found that increased tumor growth, measured by the DNA SPF, was associated with elevated serum progesterone and smoking in the premenopasual patients and with aneuploidy in the whole group. In study II, comprising 128 patients, survival length related to hormone levels and SPF was evaluated in women who died of cervical cancer. In both pre- and postmenopausal women, who died of cervical cancer, SPF at or above 12% was correlated with reduced survival. There was significant positive correlation between a low serum estradiol/progesterone ratio and short survival in those premenopausal women who died of cancer (p=0.02). In study III, ten-year follow-up results in 128 women were compared with the expression of ten relevant tumor markers, assessed by immunohistochemistry. The overall ten-year survival rate in patients with low COX-2 and high CD4+ expression was 76%, versus 53% in the remaining women. The survival rate with absent p53 and high COX-2 expression in the tumors was 42%, versus 71%, while the corresponding figure for the combination of high COX-2 intensity and expression of c-myc was 27%, versus 62%. None of the single markers correlated significantly with outcome in the final Cox regression analyses, while five combinations did. Study IV addressed possible associations between selected tumor markers and cofactors in SCC. Ten tumor markers were examined in 128 patients. Smoking habits and previous oral contraceptive use were recorded. Serum estradiol and progesterone levels were evaluated in 80 women. Highly significant associations were found between strong c-myc staining and increased progesterone, low EGFR staining and high serum estradiol, and absence of p53 staining and smoking. There was an association between absence of p53 and high serum progesterone. In study V, LRIG1 expression was studied in 128 patients and was compared with expression of nine other tumor markers, smoking history, hormone levels, and prognosis. LRIG1 appears to be a significant prognostic predictor in early stage SCC, independent of the other tumor markers that were studied.  Diminished expression in advanced cancer stages and the inverse correlation to serum progesterone and smoking indicate that LRIG1 is a tumor suppressor in squamous cell cervical cancer. Conclusion: The results of these studies support a role of progesterone as a promoter of cervical cancer and indicate that smoking is associated with tumor progression. A combination of tumor markers might be of help in prognostic prediction. LRIG1 acts as a tumor suppressor. These findings might contribute towards greater understanding of prognostic prediction of squamous cell cervical cancer.
185

Characterization of the role of acid ceramidase in adrenocortical steroid hormone biosynthesis

Lucki, Natasha Chrystman 14 November 2011 (has links)
Sphingolipids modulate multiple cellular functions, including steroid hormone biosynthesis. Sphingosine is an antagonist ligand for the nuclear receptor steroidogenic factor 1 (SF-1), which is the primary transcriptional regulator of most steroidogenic genes. Furthermore, sphingosine-dependent repression of SF-1 function is dependent on the expression of acid ceramidase (ASAH1), an enzyme that forms sphingosine. Based on these data, I hypothesized that ACTH/cAMP signaling regulates ASAH1 function at both transcriptional and post-transcriptional levels. In addition, because SF-1 is predominantly a nuclear protein, I postulated that ASAH1 modulates SF-1 function and, therefore, steroidogenic gene expression by controlling the nuclear concentrations of SPH. To test these hypotheses, I first examined the effect of chronic ACTH/cAMP signaling on the transcription of the ASAH1 gene. Next, the functional significance of ASAH1 expression in adrenocortical cells was probed by generating an ASAH1-knockdown cell line. I subsequently characterized the role of ASAH1 as a transcriptional nuclear receptor coregulator. Finally, I defined the role of sphingosine-1-phosphate, a bi-product of ASAH1 activity, in the acute phase of cortisol biosynthesis. Using a variety of experimental approaches, I identified cAMP response element binding protein as an essential transcriptional activator of the ASAH1 gene. Analysis of adrenocortical cells lacking ASAH1 revealed that ASAH1 is a global regulator of steroidogenic capacity. Furthermore, I identified ASAH1 as a nuclear protein and defined the molecular determinants of the interaction between ASAH1 and SF-1. Collectively, this body of work establishes the integral role of ASAH1 in the regulation of ACTH-dependent adrenocortical cortisol biosynthesis.
186

Untersuchungen zur uterinen Expression von Choriongonadotropin und Relaxin sowie weiteren gewebemodulierenden Faktoren im Implantationszeitraum bei Weißbüschelaffen (Callithrix jacchus)

Ebert, Katja 25 November 2013 (has links) (PDF)
Die Implantation einer Blastozyste im Uterus stellt für den maternalen Organismus eine große Herausforderung dar. Neben morphologischen Veränderungen des Endometriums sind Anpassungen auch im Immun- und Gefäßsystem notwendig. Kenntnisse über die verantwortlichen Faktoren für diese Prozesse sind bei Menschen und anderen Primaten noch immer unvollständig. Dabei sind Implantationsstörungen oftmals Ursache von Fruchtbarkeitsproblemen (SHARKEY und SMITH 2003). Besonders im Bereich der assistierten Reproduktion stellen implantationsbedingte Probleme eine Hauptursache für geringe Erfolgsraten dar (APLIN und KIMBER 2004). Das Ziel der Erforschung von Mechanismen im Zusammenhang mit der Implantation ist es, ein besseres Verständnis für die physiologischen und auch pathologischen Vorgänge zu erlangen. In dessen Folge die Erkenntnisse für die Behandlung von Implantationsstörungen genutzt werden könnten. Anhand des in der reproduktionsbiologischen Forschung etablierten Primatenmodells des Weißbüschelaffen (Callithrix jacchus) wurde in der vorliegenden Arbeit die Expression ausgewählter Faktoren in verschiedenen Zyklusphasen mit dem Schwerpunkt der Implantationsphase untersucht. Dafür wurden zeitlich genau terminierte Uterusproben von konzeptiven und nicht-konzeptiven Tieren entnommen und molekularbiologisch, histologisch und immunhistochemisch analysiert. Erstmals konnte im Uterus von Weißbüschelaffen die zeitliche und räumliche Regulierung von Choriongonadotropin (CG), Östradiolrezeptor-α (ERα), Östradiolrezeptor-ß (ERß), Progesteronrezeptor (PR), Aromatase (ARO), 17β-Hydroxysterois-Dehydrogenase Typ 7 (17β-HSD7) sowie Relaxin (RLN) und Relaxinrezeptor (RXFP1) auf Gen- und Proteinebene in verschiedenen Zyklusphasen in der vorliegenden Vollständigkeit dargestellt werden. Alle in dieser Arbeit untersuchten Faktoren zeigten eine rezeptorspezifische Veränderung der Expressionsmuster, auf räumlicher und zeitlicher Ebene im Verlauf des Implantationsprozesses. Es konnte dargestellt werden, dass die feto-maternale Kommunikation bereits vor dem direkten Kontakt der Blastozyste mit dem Endometrium beginnt. So wurde bei konzeptiven Tieren eine verstärkte Expression von CG, ERα, PR, 17β-HSD7 und RXFP1 in der Implantationsphase nachgewiesen. Diese Faktoren sind geeignete Kandidaten für weiterführende Untersuchungen und Evaluierung von Markern für die Präimplantationsphase und rezeptiven Uteri von Weißbüschelaffen. Die ebenfalls untersuchten Faktoren ERβ, ARO und RLN zeigten Expressionsmuster, welche erst nach der Implantation bei konzeptiven Tieren Unterschiede aufwiesen. Aus diesem Grund sind diese Faktoren nicht als frühe Marker der Implantationsphase geeignet, gleichwohl sie wichtige Funktionen in der Postimplantationsphase übernehmen. Die Ergebnisse dieser Arbeit verdeutlichen, dass nicht alleine ein einzelner Faktor eine herausragende Bedeutung im Implantationsprozess hat, sondern vielmehr ein äußerst komplexes Netzwerk von Signalen nötig ist, um eine erfolgreiche Gravidität zu gewährleisten. Die Aufgabe der Steroidrezeptoren ERα und PR liegt in der grundlegenden Bereitstellung eines rezeptiven Uterus während des Implantationszeitfensters. Gleichzeitig erfolgt eine sehr genau koordinierte Regulation dieser Steroidrezeptoren über die lokal produzierten Faktoren CG, ARO, 17β-HSD7, RLN und der Rezeptoren RXFP1 und ERβ. Neben den morphologischen Veränderungen des Endometriums, sind einzelne Faktoren auch bei der Angiogenese und Entwicklung der maternalen Immuntoleranz beteiligt. Es kann demnach davon ausgegangen werden, dass die präzise Regulation dieser Faktoren eine essentielle Voraussetzung für den Erfolg der Implantation und Gravidität ist.
187

Steroid-dependent regulation of the oviduct: A cross-species transcriptomal analysis

Cerny, Katheryn L. 01 January 2015 (has links)
Reproductive success depends on a functional oviduct for gamete storage, maturation, fertilization, and early-conceptus development. The ovarian-derived sex steroids estradiol and progesterone are known to affect functionality of the oviduct. Advances in microarray and NanoString technology allow for gene expression analysis to increase understanding of processes critical for fertility. Studies were conducted to investigate mechanisms regulating oviductal function in cattle and mice by using the Bovine Gene 1.0 ST array and the Mouse Gene 430-2.0 arrays (Affymetrix Inc., CA), respectively. For the first study, oviducts were collected from heifers assigned to luteal or follicular phase groups. In the second study oviducts were collected from immature mice with a global deletion of estrogen receptor-1 (ESR1) and their wild-type littermates at 23 days of age or 48 hr after treatment with 5 IU of PMSG. Following microarray hybridization, the resulting datasets were analyzed using Partek Genomics Suite 6.6 (Partek Inc., MO). The results of the first two studies illustrated a dynamic hormonal regulation of the oviductal epithelium and revealed the identity of novel genes affecting fertility in cattle and gave us insights into the genes regulated by estrogen and ESR1 in mice. Many genes identified as differentially regulated are believed to play an integral role in the regulation of oviductal inflammation. Therefore, the objective of the third study was to test the hypothesis that intraperitoneal administration of E. Coli-derived lipopolysaccharide induces the expression of inflammatory mRNAs in the mouse oviduct. Mice were treated with 0, 2 μg or 10 μg of LPS from E. Coli. and killed 24 h later. Oviducts were collected for determination of inflammatory gene expression by a targeted NanoString approach using the nCounter GX Mouse Inflammation Kit (NanoString Technologies, Wa). Results indicate that systemic treatment with LPS induces inflammation in the oviducts of mice and provides evidence of a repeatable animal model of oviductal inflammation. Overall, data from these studies extends our knowledge of the mechanisms regulating oviductal functions and immune response, as well as identified target molecules and processes to improve production animal and human fertility.
188

Androgenic and oestrogenic effects on the endrocrinology of reproductive development in male and female sheep (Ovis aries L.) / by Christakis Papachristoforou.

Papachristoforou, Christakis January 1988 (has links)
Typescript. / "April 1987." / Includes bibliograpical references (leaves 160-194). / xii, 194 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Presents direct comparative information on growth and endocrinological aspects of reproductive development in intact and gonadectomized male and female Merino lambs born in autumn and treated prepubertally with either a non-aromatizable androgen (trenbolone acetate) with higher androgenic potency than testosterone, oestradiol -17beta(oestradiol), or a combination of these two steroid hormones. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Sciences, 1988
189

Reproductive history and sex hormones and their association with subclinical atherosclerosis in women with and without type 1 diabetes /

Snell-Bergeon, Janet K. January 2007 (has links)
Thesis (Ph.D. in Epidemiology) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 100-117). Free to UCD affiliates. Online version available via ProQuest Digital Dissertations;
190

Identification of candidate genes that influence sex hormone dependent disease phenotypes in mouse lupus /

Gubbels, Melanie Rae. January 2005 (has links)
Thesis (Ph.D. in Human Medical Genetics) -- University of Colorado at Denver and Health Sciences Center, 2005. / Typescript. Includes bibliographical references (leaves 104-138). Free to UCDHSC affiliates. Online version available via ProQuest Digital Dissertations;

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