Medicine and Health Sciences Commons^™

The Role Of Erp57 In Hras Intracellular Trafficking And Function., Jaime Lyn Parman

Electronic Theses and Dissertations

Ras is a central player in signal transduction that mediates cellular proliferation and differentiation. Recent evidence has shown that lipid and non-lipid modified domains participate in Ras traffic and that plasma membrane association is mediated by vectorial vesicular transport from the endomembrane system. ERp57, an ER chaperone, has been shown to specifically bind farnesylated Hras but not non-farnesylated Hras. The objective of this study was to determine if ERp57 participates in Ras trafficking and function. First, the effect of ERp57 knock down by siRNA technology on Hras function was studied; there was a reduction in ERp57 cellular levels that led …

Characterization Of Sympathetic Ganglion Sensitivity To Substance P In A Genetic And A Non-Genetic Rat Model Of Hypertension., John Daniel Tompkins

Electronic Theses and Dissertations

Intravenous injection of substance P (SP) stimulates sympathetic ganglia to evoke a greater increase in renal sympathetic nerve activity, heart rate (HR) and blood pressure (BP) in hypertensive than normotensive rats due to upregulation of the NK₁ receptor. These experiments were designed to determine the cellular basis for the enhanced ganglionic responsiveness to NK₁ agonists in spontaneously hypertensive rats (SHR) in comparison to their normotensive counterparts, Wistar-Kyoto rats (WKY). Studies were also conducted to determine whether the increased ganglion responsiveness to SP in SHR is causally related to the increased BP or is a unique characteristic of this …

Protection Of Pifithrin-Α And Melatonin Against Doxorubicin-Induced Cardiotoxicity., Xuwan Liu

Electronic Theses and Dissertations

The current studies were designed to explore the protective effects of pifithrin-α and melatonin against doxorubicin-induced cardiotoxicity. Doxorubicin was injected at a dose of 22.5 mg/kg (i.p.) in mice to induce cardiotoxic effects. Meanwhile, doxorubicin caused a significant increase of cardiac cell apoptosis following injection (14.2 ± 1.1% for doxorubicin-5 d vs. 1.8 ± 0.12% for control, P < 0.01). Ribonuclease protection assays and Western blot analyses revealed that doxorubicin upregulated the p53-dependent genes Bax, BclxL, and MDM2 at least 2-fold. p53 was phosphorylated at Ser 15 in mouse hearts 1 h following doxorubicin injection, and p38 and ERK1/2 MAPKs mediated the phosphorylation of p53. In addition, caspases-3 and -9 were activated 24 h after doxorubicin injection. A p53 inhibitor, pifithrin-α, inhibited doxorubicin-induced apoptosis when administered at a dose of 2.2 mg/kg. Pifithrin-α abolished p53 transactivation activity, but did not influence doxorubicin-induced phosphorylation at Ser 15. By effectively inhibiting the expression of p53-dependent genes, pifithrin-α blocked doxorubicin-induced activation of caspases-3 and -9, thereby preventing cardiac apoptosis. In addition, pifithrin-α attenuated doxorubicin-induced structural and functional damages, without diminishing its anti-tumor efficacy on p53-null PC-3 cancer cells. The protective effects of melatonin and its metabolite 6-hydroxymelatonin on doxorubicin-induced cardiac dysfunction were evaluated in an isolated perfused mouse hearts and in vivo doxorubicin-treated mice. While perfusion of mouse hearts with 5 μM doxorubicin for 60 min resulted in a 50% suppression of HRxLVDP and a 50% reduction of coronary flow, pre-exposure of hearts to 1 μM melatonin or 6-hydroxymelatonin eased the cardiac …

Activation Of Ca2+-Activated K+ Channels And Cell Migration By Hepatocyte Growth Factor/Scatter Factor In Madin-Darby Canine Kidney Cells., Min Jin

Electronic Theses and Dissertations

Hepatocyte Growth Factor/Scatter Factor (HGF/SF) stimulates migration of various cells and has been linked via Met tyrosine kinase signaling to transformation and the metastatic phenotype. HGF/SF-Met signaling also plays a role in malignancy. Migration of transformed MDCK-F cells depends on activation of a charybdotoxin (ChTX)-sensitive, volume-activated membrane K⁺ current. Patch-clamp electrophysiology and transwell migration assays were used to study the effects of HGF/SF on membrane K⁺ currents and cell migration in MDCK II cells. HGF/SF activated membrane K⁺ currents that increased over 24 hr, and these could be modulated by altering intracellular free calcium concentration [Ca^{2+ …}

Dose-Response Effects Of Lithium On Spatial Memory In The Black Molly Fish., Thomas Kyle Creson

Electronic Theses and Dissertations

Lithium continues to be widely prescribed for the management of bipolar disease, yet cognitive impairment-related side effects promote noncompliance of the treatment regimen. We have introduced a novel animal model, the black molly fish, to study dose-response effects of lithium on short-term (STM) and long-term (LTM) memories. We developed a method utilizing capillary ion analysis (CIA), to measure plasma and brain lithium levels employed in our behavioral studies. We then developed an appropriate testing environment to ascertain learning capacities of these fish. We established that black mollies could adequately perform a forced-choice spontaneous alternation (SA) task used extensively in rodents …

A New Immunoassay For Quantification Of A Novel Cancer Antigen In Serum And Immunostaining Of Carcinoma Tissues And Cultured Cells Revealing The Antigenic Cellular Location., Emily Christine Mcduffee

Electronic Theses and Dissertations

The purpose of this study is 1) to examine the presence of the antigen in serum by employing a newly developed ELISA immunoassay that quantifies the total antigen and bound antigen (antigen-antibody complex) using polyclonal chicken antibodies directed against an IgM-binding epitope of the new antigen, and 2) to determine the location of the antigen in carcinoma and normal cells. Sera from healthy volunteers (n = 147) and cancer patients (n = 26) were compared for both bound and total antigen concentrations using the new ELISA. Healthy volunteers were subdivided into three groups: those with a personal history of cancer …

Evolution Of Lake Malawi Cichlid Fishes (Perciformes: Teleostei), Peter F. Smith

Electronic Theses and Dissertations

The cichlid fish species flocks of East Africa provide a compelling model system in which to study the process of speciation. In Lake Malawi, greater than 1000 species of cichlids have emerged since the filling of the lake basin about 1 million years ago. Over 99% of the Lake Malawi haplochromine cichlids are endemic, suggesting that most of this diversification has taken place within the temporal and spatial boundaries set by the Lake's shores. Moreover, many of these species are endemic to small areas within the lake, indicating that speciation has occurred very recently or perhaps is in progress in …

Hiv Tat Protein Activates Endothelial Cells Through Nfκb And Map Kinase Pathways., Jason L. Henry

Electronic Theses and Dissertations

HIV infection has been shown to predispose patients to accelerated development of heart disease. One mechanism for this pathology may involve endothelial activation either by HIV itself or by its secreted proteins, gp120 (a viral envelope protein) and tat (a protein that upregulates transcription of viral genes). We have studied the effects of gp120 and tat on signaling and production of inflammatory cytokines by Human Pulmonary Artery Endothelial Cells (HPAEC). HPAEC were stimulated at varying time points with combinations of gp120, tat, and monokines (IL-1β and TNFα). Cell lysate fractions were analyzed for MAP Kinase activity and NFκB activation, and …

The Signaling Pathway Of Oxysterol Induced Apoptosis In Chinese Hamster Ovary (Cho)-K1 Cells., Lin Yang

Electronic Theses and Dissertations

Apoptosis, a form of genetically programmed cell death, plays a key role in regulation of cellularity of the arterial wall. During atherogenesis, improper apoptosis may cause abnormalities of arterial morphogenesis, wall structural stability, and metabolisms. It has been well established that vascular cells undergo apoptosis after uptake of oxidized low-density lipoprotein (oxLDL). Thus, an analysis of the signaling pathway of apoptotic induction by oxLDL is of value in understanding the development of atherosclerotic plaque. In order to elucidate the signaling pathway of apoptosis induced by oxLDL, we have used Chinese hamster ovary (CHO)-K1 cells treated with a potent oxysterol, 25-hydroxycholesterol …

30s Ribosomal Subunit Assembly Is A Target For Inhibition By Aminoglycoside Antibiotics In Escherichia Coli., Roopal Manoj Mehta

Electronic Theses and Dissertations

Antibacterial agents specific for the 50S ribosomal subunit not only inhibit translation but also prevent assembly of that subunit. I examined the 30S ribosomal subunit in growing Escherichia coli cells to see if antibiotics specific for that subunit also had a second inhibitory effect. I used the aminoglycoside antibiotics paromomycin and neomycin, which bind specifically to the 30S ribosomal subunit. Both antibiotics inhibited the growth rate, viable cell number, and protein synthesis. I used a ³H-uridine pulse and chase assay to examine the kinetics of ribosome subunit assembly in the presence and absence of each antibiotic. Analysis revealed a …

Behavioral Changes In Adult C57bl/6j Mice Following Prenatal Exposure To Ethanol., Kevin Wade Nunley

Electronic Theses and Dissertations

Fetal Alcohol Syndrome (FAS) labels children with physical, mental and behavioral deficits exposed to alcohol in utero. Current research indicates that timing of alcohol exposure of the embryo/fetus is a critical determinant of the behavioral deficits associated with FAS. This study represents a model for binge drinking, in which C57BL mouse embryos were exposed to alcohol during 2 separate critical periods of brain development, gestational day (GD) 7 or 8. As adults, the offspring were tested to determine if loco-motor activity and emotional reaction to a novel environment had been affected. Significant differences due to treatment and sex were …

Molecular Studies Involving The Rev Protein Of Caprine Arthritis Encephalitis Virus And Visna Virus., Bridget Michele Graves

Electronic Theses and Dissertations

Caprine Arthirtis Encephalitis Virus (CAEV) and Visna Virus are two viruses of the lentivirus family. They encode three structural genes (gag, pol, and env) and two regulatory genes (rev and tat). The Rev protein regulates Gag, Pol and Env expression by transporting their mRNAs to the cytoplasm by binding to the RRE (Rev Response Element) found on their mRNAs. Previous studies have indicated that Rev may be toxic to transfected cells, overexpression of exogenous RREs or a better binding RRE can inhibit Rev activity and Rev-C (CAEV Rev) can trans-activate RRE-V (Visna Virus …

Characterization Of Seca-Sod Operon In Borrellia Burgdorferi., Tonya Lynn Nichols

Electronic Theses and Dissertations

Borrelia burgdorferi, the causative agent of Lyme disease, has been characterized as a microaerophilic spirochete. O2 consumption and utilization potentially yield reactive oxygen intermediates, such as superoxide, hydroxyl radicals, and hydrogen peroxide. This study investigated the expression of the sod gene, which encodes the only, identified oxidative defense mechanism in B. burgdorferi. Using primer extension analysis and RT-PCR, it was found that sod and secA are organized as a single transcriptional unit under the control of σ70-like promoter upstream of the secA open reading frame. Generally, gene expression decreases with increased distance from the promoter; however, secA expression was observed …

Characterization Of 50s Ribosomal Subunit Assembly Inhibition In Erythromycin Treated Escherichia Coli Cells., Jerry Edward Usary

Electronic Theses and Dissertations

Erythromycin has long been recognized for its ability to inhibit protein synthesis by interfering with mRNA translation on the bacterial ribosome. We have recently shown that erythromycin also inhibits the assembly of the 50S ribosomal subunit in growing bacterial cells. The nature of this assembly inhibition has been investigated using ³H-uridine pulse-chase labeling of control and erythromycin treated E. coli cells.

Subunit assembly was examined by sucrose gradient centrifugation of labeled cell lysates. Normal assembly kinetics of subunit assembly were observed in control cells at 37°C. Formation of the 30S subunit was completed by 7.5 minutes and assembly of …

Present Practices In Testing Deaf Children., Mary Dillon Guilmartin 1893-1971

Electronic Theses and Dissertations

No abstract provided.

The Effect Of Experimental Liver Damage On The Blood Picture Of The Dog., H. D. Bruner

Electronic Theses and Dissertations

No abstract provided.

The Cause Of Vascular Sclerosis In Essential Hypertension And Related Phenomena, Claude W. Chappell

Electronic Theses and Dissertations

No abstract provided.

A Study Of The Diffusibility And Non-Diffusibility Of Magnesium And Calcium In Normal Blood Sera., Louis J. Halle

Electronic Theses and Dissertations

No abstract provided.

The Influence Of The Brain Upon The Liver As A Blood Concentrating Organ In Fever., Benjamin F. Aydelotte 1899-1956

Electronic Theses and Dissertations

No abstract provided.