Life Sciences Commons^™

Sex Chromosome Ratios And Aneuploidy Rates In The Zona Pellucida Selected Spermatozoa From Normal And Subfertile Men, Qinuo Fan Van Dyk

Theses and Dissertations in Biomedical Sciences

The human hemizona has been demonstrated to select spermatozoa with good motility, normal morphology, and the capacity to undergo the zona-induced acrosomal reaction. The studies conducted here are directed at using the human hemizona to investigate two key questions: (1) whether human X-chromosome bearing spermatozoa (X-sperm) and Y-chromosome bearing spermatozoa (Y-sperm) differ in their functional survival time (assessed by their capacity to bind to the human zona pellucida) after prolonged in vitro incubation, and (2) whether hemizona-bound spermatozoa have a reduced aneuploidy rate compared to unbound (and therefore, unselected) spermatozoa?

In the functional survival study, donor spermatozoa were held in …

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 …

Type Ii Estrogen Binding-Site Agonist: The Synthesis And Biological Evaluation Of The Enantiomers Of Methyl-Para-Hydroxyphenyllactate (Mehpla), Lester G. Pretlow

Theses and Dissertations in Biomedical Sciences

The function of the type II estrogen binding site (EBS) has yet to be determined. However, a high affinity ligand for the binding site has been identified through HPLC and GC-MS. This ligand, MeHPLA, bears a structural relationship to a group of compounds called "phytoestrogens" which, along with MeHPLA, have been observed to suppress the cellular proliferation of estrogen sensitive MCF-7 breast cancer cells in vitro. Additionally, MeHPLA has been observed to suppress the growth of rat uteri in vivo. The high affinity of MeHPLA for the type II EBS suggests that this interaction is responsible for the observed suppression …

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 …

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 …

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, …

Cγ- And Cα-Subunits Provide The Specificity For Camp/Pka Function, Wei Qing Zhang

Theses and Dissertations in Biomedical Sciences

The Cα and Cγ of the cAMP-dependent protein kinase (PKA) are two highly homologous (83% amino acid identity), yet functionally distinct isozymes in vitro for substrate and pseudosubstrate specificity, and in intact cells for cell phenotypes (Beebe, 1992).

To determine the molecular mechanisms underlying the distinct functions in cell phenotypes, in vitro experiments were designed to make a detailed comparison of Cγ and Cα for substrate and pseudosubstrate specificity. To this end, Cγ and Cα were expressed m mammalian cells, bacteria and Sf9 insect cells using baculovirus. Abundant expression of active enzyme was cell system specific. Cγ and Cα expressed …

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. …

Abnormalities In Post-Translational Processing Of Platelet Rap 1b In Niddm: A Possible Cause Of Platelet Hyperactivity And Cardiovascular Disease In Diabetes, Elizabeth Ann Hall

Theses and Dissertations in Biomedical Sciences

Post-translational processing is critical for the appropriate subcellular localization and function of platelet G-proteins. The majority of the platelet responses to agonists are mediated through specific receptor/G-protein complexes. Therefore, G-protein activity is central to "normal" platelet activity (i.e. aggregation). We have shown that Simvastatin, the in vivo inhibitor of HMG CoA Reductase and therefore isoprenoid synthesis, inhibits the post-translational processing of specific platelet G-proteins and alters platelet responses to agonists. These results show the importance of post-translational processing of G-proteins to platelet activity. Altered post-translational processing of specific G-proteins may explain platelet hyperactivity and the increased incidence of cardiovascular disease …