• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 806
  • 532
  • 90
  • 82
  • 34
  • 24
  • 20
  • 19
  • 13
  • 12
  • 12
  • 12
  • 12
  • 12
  • 12
  • Tagged with
  • 1992
  • 478
  • 348
  • 226
  • 199
  • 197
  • 193
  • 185
  • 170
  • 149
  • 142
  • 136
  • 134
  • 117
  • 115
  • 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.
91

Characterisation of the development and hormonal regulation of the ovarian lymphatic vasculature.

Brown, Hannah Mary January 2009 (has links)
The ovary provides a niche environment where female germ cells (or oocytes) are generated, stored within follicles and later matured in preparation for use during reproductive life. Following an extensive period of quiescence, which in human, may be up to forty years; the follicle surrounding the oocyte begins to grow, promoting maturation of the oocyte, and culminating in the expulsion of a fully mature oocyte in preparation for fertilisation. These events occur cyclically as part of the menstrual (or estrus) cycle and involve extensive remodelling of both the follicle and its surrounding extracellular tissue. Cyclic follicle activation and growth is also associated with concurrent remodelling of the blood vasculature within the ovary, specifically the vessels surrounding the growing follicle. These blood vascular remodelling changes are well explored and have been demonstrated to be necessary for follicle growth, hormone synthesis, ovulation and for the development and function of the corpus luteum. Physiologically, the lymphatic vasculature is known to closely interact with the blood vasculature and plays a number of important physiological roles including the return of extra-vascular fluid to the blood circulation, and in turn, maintenance of systemic fluid homeostasis. Additionally the lymphatic network is required for the trafficking of immune cells from the periphery to lymph nodes; during the initiation of an immune response and for the absorption of lipids and lipid soluble vitamins in the gastrointestinal tract. The lymphatic vasculature develops and functions concomitantly with the blood vasculature; however unlike the blood vasculature, the aetiology of lymphatic vasculature within the ovary is unknown. It is unclear whether lymphatic remodelling events occur in association with folliculogenesis and are necessary for fertility, as is seen with the blood vasculature. To elucidate the mechanisms involved in the establishment and remodelling of the lymphatic vasculature within the ovary, I undertook expansive characterisation of its development and hormonal regulation. I exploited both hormonal manipulation and a known model of disrupted ovarian lymphatic development, the Adamts1 null mouse line, to examine the mechanisms controlling ovarian lymphangiogenesis. Quantitative morphometric analysis of vessel size and number in postnatal mouse ovary revealed that the ovarian lymphatic vasculature develops postnatally between day 8.5 and 12.5, and in synchrony with induction of ovarian CYP19a1 (Aromatase); the time when secondary follicles become FSH-responsive and estrogenic. The establishment of the lymphatic vasculature was also associated with the induction of pro-lymphangiogenic growth factors Vegfc and Vegfd, and their receptor, Vegfr3. Formation of ovarian lymphatics required the matrix-remodelling protease Adamts1, since ovaries from Adamts1⁻/⁻ mice failed to undergo normal lymphatic vascular development. FSH promoted remodelling of the existing lymphatic vascular maturation by increasing lymphatic vessel size in normal (Adamts1⁺/⁻) ovaries, and promoted the expansion of a new lymphatic vascular network by increasing vessel number and size in Adamts1⁻/⁻ ovaries. These vessel changes were also associated with the induction of prolymphangiogenic factors, Vegfc and Vegfd, as well as their receptor, Vegfr3 providing a mechanistic explanation for the hormonal mediated lymphangiogenesis. The concurrent establishment of the lymphatic vasculature with the first postnatal induction of ovarian Aromatase, and the hormone-regulated lymphangiogenesis suggests that a hormonal communication, likely estrogen, may synchronise lymphangiogenesis with folliculogenesis. Like FSH, exogenous estradiol was able to promote the expansion of a new lymphatic vascular network by increasing vessel number and size in Adamts1⁻/⁻ ovaries. Additionally, FSH-analog eCG was able to enhance ovarian lymphangiogenesis during the window of lymphatic establishment (postnatal development of Adamts1 null), whilst inhibition of the production of estradiol using the Aromatase inhibitor Letrozole, during this same window failed to have any effect. This study is the first to investigate the relationship between ovarian lymphatic development and remodelling and folliculogenesis. The present studies reveal that the ovary undergoes lymphatic vascular remodelling, described elsewhere as adult or secondary lymphangiogenesis and that this process involves hormonal contributions from FSH and estradiol, as well as the extracellular matrix protease, Adamts1. This work provides the first evidence of a malleable lymphatic system and a model for regulation of normal adult lymphangiogenesis, and may one day be used to explore ways in which to regenerate damaged vessels to cure lymphatic diseases and disorders. These results also significantly advanced the understanding of the tightly regulated processes controlling fluid dynamics within the ovary. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1454847 / Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2009
92

Characterisation of the development and hormonal regulation of the ovarian lymphatic vasculature.

Brown, Hannah Mary January 2009 (has links)
The ovary provides a niche environment where female germ cells (or oocytes) are generated, stored within follicles and later matured in preparation for use during reproductive life. Following an extensive period of quiescence, which in human, may be up to forty years; the follicle surrounding the oocyte begins to grow, promoting maturation of the oocyte, and culminating in the expulsion of a fully mature oocyte in preparation for fertilisation. These events occur cyclically as part of the menstrual (or estrus) cycle and involve extensive remodelling of both the follicle and its surrounding extracellular tissue. Cyclic follicle activation and growth is also associated with concurrent remodelling of the blood vasculature within the ovary, specifically the vessels surrounding the growing follicle. These blood vascular remodelling changes are well explored and have been demonstrated to be necessary for follicle growth, hormone synthesis, ovulation and for the development and function of the corpus luteum. Physiologically, the lymphatic vasculature is known to closely interact with the blood vasculature and plays a number of important physiological roles including the return of extra-vascular fluid to the blood circulation, and in turn, maintenance of systemic fluid homeostasis. Additionally the lymphatic network is required for the trafficking of immune cells from the periphery to lymph nodes; during the initiation of an immune response and for the absorption of lipids and lipid soluble vitamins in the gastrointestinal tract. The lymphatic vasculature develops and functions concomitantly with the blood vasculature; however unlike the blood vasculature, the aetiology of lymphatic vasculature within the ovary is unknown. It is unclear whether lymphatic remodelling events occur in association with folliculogenesis and are necessary for fertility, as is seen with the blood vasculature. To elucidate the mechanisms involved in the establishment and remodelling of the lymphatic vasculature within the ovary, I undertook expansive characterisation of its development and hormonal regulation. I exploited both hormonal manipulation and a known model of disrupted ovarian lymphatic development, the Adamts1 null mouse line, to examine the mechanisms controlling ovarian lymphangiogenesis. Quantitative morphometric analysis of vessel size and number in postnatal mouse ovary revealed that the ovarian lymphatic vasculature develops postnatally between day 8.5 and 12.5, and in synchrony with induction of ovarian CYP19a1 (Aromatase); the time when secondary follicles become FSH-responsive and estrogenic. The establishment of the lymphatic vasculature was also associated with the induction of pro-lymphangiogenic growth factors Vegfc and Vegfd, and their receptor, Vegfr3. Formation of ovarian lymphatics required the matrix-remodelling protease Adamts1, since ovaries from Adamts1⁻/⁻ mice failed to undergo normal lymphatic vascular development. FSH promoted remodelling of the existing lymphatic vascular maturation by increasing lymphatic vessel size in normal (Adamts1⁺/⁻) ovaries, and promoted the expansion of a new lymphatic vascular network by increasing vessel number and size in Adamts1⁻/⁻ ovaries. These vessel changes were also associated with the induction of prolymphangiogenic factors, Vegfc and Vegfd, as well as their receptor, Vegfr3 providing a mechanistic explanation for the hormonal mediated lymphangiogenesis. The concurrent establishment of the lymphatic vasculature with the first postnatal induction of ovarian Aromatase, and the hormone-regulated lymphangiogenesis suggests that a hormonal communication, likely estrogen, may synchronise lymphangiogenesis with folliculogenesis. Like FSH, exogenous estradiol was able to promote the expansion of a new lymphatic vascular network by increasing vessel number and size in Adamts1⁻/⁻ ovaries. Additionally, FSH-analog eCG was able to enhance ovarian lymphangiogenesis during the window of lymphatic establishment (postnatal development of Adamts1 null), whilst inhibition of the production of estradiol using the Aromatase inhibitor Letrozole, during this same window failed to have any effect. This study is the first to investigate the relationship between ovarian lymphatic development and remodelling and folliculogenesis. The present studies reveal that the ovary undergoes lymphatic vascular remodelling, described elsewhere as adult or secondary lymphangiogenesis and that this process involves hormonal contributions from FSH and estradiol, as well as the extracellular matrix protease, Adamts1. This work provides the first evidence of a malleable lymphatic system and a model for regulation of normal adult lymphangiogenesis, and may one day be used to explore ways in which to regenerate damaged vessels to cure lymphatic diseases and disorders. These results also significantly advanced the understanding of the tightly regulated processes controlling fluid dynamics within the ovary. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1454847 / Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 2009
93

Development of a non-invasive technique to determine reproductive hormones in cetaceans

Hogg, Carolyn J January 2006 (has links)
Doctor of Philosophy (PhD) / Reproductive physiology plays a vital role in population growth and vitality. Baseline data on reproductive physiology and a comprehensive knowledge of breeding biology are essential to conservation management. Great whales have been hunted from the 16th century to the present day. Although many populations are increasing there are populations with low or declining reproductive rates. In 2001 it was recommended to the International Whaling Commission that new techniques be developed to assess the internal physiology of great whales. This study, based on this recommendation, aims to develop analytical methods to assess reproductive hormones in cetacean blow samples and determine the feasibility of its use with free-swimming great whales. A method for the assessment of steroid hormone concentrations using liquid chromatography-mass spectrometry (LC-MS) was developed and validated. These methods were then used to determine testosterone and progesterone concentrations in saliva and blow of bottlenose dolphins. The stability of testosterone and progesterone was found to be a major issue. Without inhibitors, hormone concentrations increased by up to 65% over three hours at 21oC. Storing samples at low temperatures (-20oC or -80oC) slowed but did not cease the rate of change. The addition of inhibitors, manganese chloride and amoxycillin potassium/clavulanate, improved the stability of testosterone and progesterone. It is proposed that when using dolphin saliva and blow samples to measure reproductive hormones the samples are extracted as soon as possible after collection to prevent degradation. This study highlighted the need to address steroid hormone stability prior to any longterm biological program, to ensure that changes seen in hormone concentration are due to biological activity rather than storage. A technique to collect blow samples from free-swimming great whales was developed. This technique, in conjunction with the specially developed LC-MS methods allowed for the determination of testosterone and progesterone concentrations in humpback whale blow. The techniques developed in this study to determine reproductive hormones in cetacean saliva and blow have applications for both captive and wild population studies. In captive institutions, saliva and/or blow can be used to monitor reproductive cycling in both females and males. As it is noninvasive it can be used on a daily basis with minimal stress to the animals. The use of blow sampling has the capacity to improve our understanding of reproductive cycling in great whales as it can be used to sample animals in both the breeding and feeding areas. This technique may allow us to now examine whether reproductive dysfunction is playing a role in the slow recovery of critically endangered species such as the North Atlantic right whale.
94

The proximal promoter of the melanocortin 4 receptor harbors regulatory elements responsible for brain preferential expression

Lamar, Clifford R. January 2007 (has links)
Thesis (M.S. in Molecular Physiology and Biophysics)--Vanderbilt University, Dec. 2007. / Title from title screen. Includes bibliographical references.
95

Role of corticotropin-releasing factor, somatostatin and leptin in vagal nerve function and control of gastric emptying /

Smedh, Ulrika, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 7 uppsatser.
96

Functional characterization and pharmacological rescue of the human and porcine neural melanocortin receptors

Fan, Zhenchuan, Tao, Ya-Xiong. January 2008 (has links)
Dissertation (Ph.D.)--Auburn University, / Abstract. Includes bibliographic references (p.110-134)
97

The biostimulatory effect of bulls on the hypothalamic-pituitary-adrenal and ovarian axes and on temporal aspects of resumption of ovarian cycling activity in primiparous, postpartum, anestrous, suckled, beef cows

Tauck, Shaun Austin. January 2008 (has links) (PDF)
Thesis (PhD)--Montana State University--Bozeman, 2008. / Typescript. Chairperson, Graduate Committee: James G. Berardinelli. Includes bibliographical references (leaves 131-144).
98

Lutalyse induces uterine-ovarian PGF₂[alpha] release in sheep : a critical component of induced luteolysis /

Wade, Dawn E., January 1994 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 96-109). Also available via the Internet.
99

Relationships among progesterone, estradiol-17[beta], 13, 14- dihydro-15-keto-prostaglandin F₂a and prostaglandin F₂a in intact ewes around the time of luteolysis /

Fortin Suyapa, January 1991 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 76-83). Also available via the Internet.
100

Preparation and biological properties of follicle stimulating hormone from sheep pituitary glands

Duraiswami, Sundaravaradan, January 1962 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1962. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 70-73).

Page generated in 0.0505 seconds