Life Sciences Commons^™

Interaction Of Acth And Estradiol In The Regulation Of Growth, Differentiation, And Steroidogenic Maturation Of The Baboon Fetal Adrenal Gland, Maria Gomez Leavitt

Theses and Dissertations in Biomedical Sciences

The present study determined whether the growth of, as well as ACTH receptor and P-450 enzyme messenger ribonucleic acid and/or protein levels in the baboon fetal adrenal are dependent upon fetal pituitary ACTH during mid and late gestation and the mechanism by which placental estrogen modulates ACTH actions. Administration of betamethasone (3mg/day) to baboon mothers on days 60-99 of gestation and to the fetus (0.6 mg/, n = 4) or to the fetus (0.6mg) and mother (6 mg/ml; n = 4) every other day between days 150-164 of gestation (term = 184 days) decreased (P $53β-hydroxysteroid dehydrogenase-isomerase (3β-HSD(+)ctochrome P450 17α-hydroxylase, …

The Cellular And Molecular Dynamics Of The Queuosine Modification In Transfer Rna: Definition, Modulation, Deficiencies And Effect Of The Queuosine Modification System, Rana C. Morris

Theses and Dissertations in Biomedical Sciences

The presence of the queuosine modification in the wobble position of tRNA^asn, tRN^asp, tRNA^his, and tRNA^tyr is associated with a decrease in cellular growth rate, an increase in the ability to withstand environmental stress, and differentiation of pleuripotent cells into mature phenotypes. The loss of this normal modification is strongly correlated with neoplastic transformation and tumor progression of a wide variety of cancers.

The "normal" system for formation of the queuosine modification in tRNA was studied in human fibroblast cell cultures and in mouse, rat and human liver tissues. The queuosine modification system …

Endothelial Nitric Oxide Synthase And Growth Factor Regulation Of Flow-Mediated Vascular Remodeling, David Anthony Tulis

Theses and Dissertations in Biomedical Sciences

This study was designed to characterize structural remodeling of male Wistar rat mesenteric arteries exposed to elevated blood flow in vivo for 1, 3, or 7 days. A series of arterial ligations induced blood flow increases in ileal and second-order branch arteries compared to same animal control vessels. Neither mean carotid nor local mesenteric arterial pressures changed significantly pre- to post-ligation. The primary flow-mediated force in both vessels was shear stress with possible involvement of acute stretch-induced wall stress in the ileal artery. Significant luminal expansion and medial wall hypertrophy occurred in the ileal and second-order arteries in a time-dependent …

Fluorescence In Situ Hybridization Analysis Of Human Embryos Derived From In Vitro And In Vivo Matured Oocytes, Constance Descisciolo

Theses and Dissertations in Biomedical Sciences

Despite adequate hormonal stimulation, oocytes collected for the purpose of in vitro fertilization and embryo transfer display several levels of nuclear maturity. Preovulatory or mature oocytes, technically those that are Metaphase I or II, are inseminated shortly after aspiration and assessed for fertilization the following day. Prophase I oocytes, also called germinal vesicle-bearing or immature oocytes, require a 24-36 hour period in culture before being exposed to spermatozoa. During this time, the majority of Prophase I oocytes complete nuclear maturation in vitro, progressing from germinal vesicle breakdown through first polar body extrusion. If inseminated, many in vitro matured oocytes fertilize …

Differential Endometrial Responses Of Primates Vs Rodents: Screening For Antiproliferative Effects Of Antiprogestins, David Williams Burleigh

Theses and Dissertations in Biomedical Sciences

The antiprogestin, mifepristone, has previously been shown to noncompetitively inhibit estrogen-induced endometrial proliferation in nonhuman primates (van Uem et al., 1989; Wolf et al., 1989b; Neulen et al., 1990; Neulen et al., 1996). For both economical and ethical reasons, we are encouraged to identify comparative laboratory rodent models which can substitute the need to use primate models. In the following study, we compared capabilities of the rat uterine weight bioassay versus a primate uterine bioassay, to identify the noncompetitive antiestrogenic/antiproliferative effects of mifepristone.

Long-term ovariectomized monkeys were exposed to exogenous 17β-estradiol (E2) and mifepristone in doses and regimes already demonstrated …

Arterial Wall Hypertrophy And Pdgf-A Expression In One-Kidney, One-Clip Hypertension And Angiotensin Ii Infusion Are Mediated By Elevated Arterial Pressure, Sheri Blair Parker

Theses and Dissertations in Biomedical Sciences

These studies were designed to characterize the relative roles of angiotensin II (ANG II) and pressure in the structural alterations that occur in experimental hypertension. Two separate studies were performed in order to differentiate these two mechanisms. First, male Wistar rats were subjected to one-kidney, one-clip (1K1C) hypertension or sham operation. Losartan, an AT1 receptor antagonist, was administered chronically to half of each surgical group beginning one day before the operation and continued until the end of the study. In a second experiment, rats were implanted with osmopumps delivering either ANG II or saline. To maintain pressure in the normotensive …

Choline Acetyltransferase And Carnitine Acetyltransferase Activity In Human Spermatozoa During Capacitation, Lisa A. Eccles

Theses and Dissertations in Biomedical Sciences

The regional distribution of ChAT activity in human spermatozoa is altered during in vitro capacitation and it correlates with the fertilizing potential of sperm.

Regional immunoreactivity in human spermatozoa as assessed by fluorescent immunocytochemistry was compared with ChAT and CaAT activity determined by enzymatic methodologies. Increasing proportions of sperm exhibited ChAT immunoreactivity along the equatorial region with a concomitant decrease in ChAT reactivity in the midpiece. Also, competitive studies with unlabeled ChAT blocked the equatorial region labeling; the unlabeled CaAT blocked staining along the midpiece region of the tail, suggesting some cross-reactivity of the ChAT antiserum with the CaAT enzyme. …