Medicine and Health Sciences Commons^™

Insights Into P53-Dependent Apoptotic Signaling And Cell Fate Vis-A-Vis Functional Cooperation Among Bcl-Xl, Cytoplasmic P53, And Puma, John C. Fisher

Theses and Dissertations (ETD)

Following DNA damage, nuclear p53 induces the expression of PUMA (p53 upregulated modulator of apoptosis), a BH3‑only protein that binds and inhibits the anti‑apoptotic BCL‑2 repertoire, including BCL‑xL. Structural investigations of PUMA and the BCL‑xL×PUMA BH3 domain complex by X‑ray crystallography and nuclear magnetic resonance (NMR) spectroscopy reveal a novel, PUMA‑induced, domain‑swapped dimerization of BCL‑xL that requires a π‑stacking interaction between PUMA W71 and BCL‑xL H113. PUMA is an intrinsically disordered protein, but upon interaction with BCL‑xL, PUMA W71 and the PUMA BH3 domain residues fold into an alpha helix and subtly remodel BCL‑xL to trigger its dimerization. Wild type …

Inhibition Of Monocyte Chemotaxis And Chemokine Macrophage Inflammatory Protein-1 Alpha, And Interleukin-8 Secretion By Lipopolysaccharide Isolated From Periodontal Pathogens, Andrew Karl Gray

Theses and Dissertations (ETD)

The vast majority of periodontal pathogens are classified as gram negative bacteria. These bacteria have an outermost membrane consisting of lipopolysaccharide (LPS), a molecule that can act as an endotoxin and elicit an immune response. The lipopolysaccharide structure consists of three major regions: oligosaccharide, core, and lipid A. Oligosaccharide is exposed on the cell surface, and lipid A anchors LPS in the outer membrane. LPS has been known to hinder certain defensive mechanisms of the immune system by secreting products that interfere with signals that promote chemotaxis of leukocytes enabling the pathogens to go unrestricted. When LPS binds to the …

Role Of Protein Kinase C Zeta (Pkcζ) In Regulation Of Epithelial Tight Junctions, Suneet Kumar Jain

Theses and Dissertations (ETD)

Occludin is hyperphosphorylated on Ser and Thr residues in intact epithelial tight junctions. The dynamics of epithelial tight junctions appear to involve reversible phosphorylation of occludin on Ser and Thr residues. In the present study we determined the role of PKCζ in occludin phosphorylation and the dynamics of tight junctions. Inhibition of PKCζ by specific PKCζ pseudo substrate rapidly reduced TER, increased inulin permeability and induced redistribution of occludin and ZO‑1 in Caco‑2 and MDCK cell monolayers without inducing cytotoxicity. Reduced expression of PKCζ also resulted in compromised tight junction integrity. Both PKCζ pseudo substrate and reduced expression of PKCζ …

The Biochemical Pathway Leading To Lpa Generation Upon Blood Coagulation, Alyssa Lynn Jefferson Bolen

Theses and Dissertations (ETD)

Platelet activation initiates an upsurge in 18:2 and 20:4 lysophosphatidic acid (LPA) production. The biochemical pathway responsible for LPA production during blood clotting is not fully understood. We have purified a phospholipase A₁ (PLA₁) from thrombin-activated human platelets using sequential chromatographic steps followed by fluorophosphonate‑biotin affinity labeling and proteomics. We identified acyl‑protein thioesterase 1 (aka. lysophospholipase A1, accession code O75608) as a novel PLA₁. Addition of this recombinant PLA₁ significantly increased the production of sn‑2‑esterified polyunsaturated LPCs and the corresponding LPAs in plasma. We next examined the regioisomeric preference of lysophospholipase …

Rna Interference For Improving The Outcome Of Islet Transplantation And Polymeric Micelle‑Based Nanomedicine For Cancer Therapy, Feng Li

Theses and Dissertations (ETD)

Ex vivo gene transfer has been used to improve the outcome of islet transplantation for treating type I diabetes. RNA interference is an effective approach for reducing gene expressions at the mRNA level. The application of RNA interference to improve the outcome of islet transplantation was reviewed in Chapter 2, where I summarized biological obstacles to islet transplantation, various types of RNAi techniques, combinatorial RNAi in islet transplantation, and different delivery strategies.

Upregulation of inducible nitric oxide synthase (iNOS) and subsequent product of radical nitric oxide (NO) impair islet β cell function. Therefore, we hypothesized that iNOS gene silencing could …

Pharmacokinetic And Pharmacodynamic Studies Of A Novel Spectinamide Series Of Antituberculosis Agents, V. N. R. Pavan Kumar Vaddady

Theses and Dissertations (ETD)

Spectinamides are novel amide derivatives of the antibiotic spectinomycin that have emerged as a new class of agents to treat tuberculosis. These agents showed potent in vitro activity against Mycobacterium tuberculosis (MTB) compared to spectinomycin and in a preliminary in vivo study in interferon gamma (IFN‑γ) knockout mice, spectinamide Lee1329 reduced the lung bacillary load of TB comparable to streptomycin. We hypothesized that the application of an iterative pharmacokinetics and pharmacodynamics (PK/PD) guided approach would facilitate the optimization of these lead compounds suitable for further development.

A series of in vitro experiments including parallel artificial membrane permeability assay (PAMPA), microsomal …

Inflammatory Proteins, Genetic Variation, And Environmental Influences On Health Care Associated Infection Development In Sepsis, Reba Antoinette Umberger

Theses and Dissertations (ETD)

The purpose of this study was to determine the impact of baseline systemic inflammation (pro‑inflammatory cytokine, anti‑inflammatory cytokine, and their ratio), genetic variability, and environment on the development of health care associated infections (HAI) among sepsis patients during their ICU stay (up to 28 days).

Methods: A prospective observation study was conducted at the Veterans Affairs Medical Center in the Medical Intensive Care Unit over an 18 month period. A total of 78 patients were enrolled within 72 hours of presenting to the ICU with sepsis. Patient were excluded if they were receiving immunosuppressants (chemotherapy or greater than one mg/kg …

Application Of A High‑Resolution Computed Radiography System In Detecting An Iodinated X‑Ray Contrast Agent: Small Animal Phantom Study, Anobel Maghsoodpour

Theses and Dissertations (ETD)

Tumor angiogenesis, the creation of new blood vessels, is the characteristic of solid tumors and crucial for their development. Iodinated contrast agents are used to increase the X‑ray detectability of zone of angiogenesis, and thus providing a means for tracking tumor growth.

The overall objective of this project was to evaluate the performance of Kodak CR 7400, a high‑resolution compact computed radiography (CR) system in detection of Omnipaque‑240, an iodinated contrast agent, in a phantom mimicking small animal tumor model.

The first phase of the project was dedicated to a comprehensive assessment of CR image quality by measuring presampled Modulation …

A Novel Shear Thinning And Thixotropic Plga Micro Particulate Suspension System For Controlled Drug Delivery, Sonia Bedi

Theses and Dissertations (ETD)

Poly lactide‑co‑glycolide (PLGA) polymer has been the polymer of choice for many parenteral controlled drug release applications. This is mainly due to the inherent advantages of this polymer i.e. biodegradability, biocompatibility and non-toxic nature. The polymer, however, has a characteristic degradation pattern whereby the final erosion phase does not begin until the polymer reaches a certain molecular weight (MW) limit. After this, the accumulated acidic degradation byproducts initiate a bulk erosion phenomenon that leads to a disruption of the polymer matrix and release of the remaining drug in a short period of time. Furthermore, most of the delivery systems or …

Novel Insights Into Ubiquitin-Like Protein E1-E2 Interactions, Asad Taherbhoy

Theses and Dissertations (ETD)

Posttranslational modification of macromolecules by ubiquitin-like proteins (UBLs) such as ubiquitin, Sumo and NEDD8 regulate a vast array of processes in the cell. Transfer of UBLs to their target generally occurs by a series of molecular handoffs down an E1‑E2‑E3 cascade. We are interested in understanding how E1‑E2 pairs interact and mediate UBL transfer. To this effect, we studied two E1‑E2 pairs: the Sumo pathway (Sumo utilizes a canonical E1 and E2) and the Atg8 pathway (Atg8 is a UBL involved in autophagy that utilizes a non-canonical E1‑E2 pair).

Sumo conjugation is initiated by the heterodimeric Aos1‑Uba2 E1 enzyme (in …

Systemic Aav-Mediated Gene Therapy Using Epo-R76e To Protect Retinal Ganglion Cells From Optic Nerve Injury And Disease, Timothy A. Sullivan

Theses and Dissertations (ETD)

Neuroprotection is a strategy to prevent or reduce neuronal cell death regardless of the underlying cause. Erythropoietin (EPO) exhibits neuroprotective effects in a variety of in vitro and in vivo models of neuronal cell death although its classical function is the regulation of red blood cell production. EPO crosses the blood brain barrier and therefore can be delivered systemically. However, long term treatment with exogenous EPO causes over stimulation of the erythropoietic pathway which can be lethal. The erythropoietic and neuroprotective pathways are regulated by different receptors; further, it is possible to modify EPO to primarily, if not solely, activate …

Characterization Of The Sigma Factor Proteins And The Dna Binding Protein Euo Of Chlamydia, Cory L. Blackwell

Theses and Dissertations (ETD)

Chlamydia spp. are prokaryotic obligate intracellular pathogens with a unique, biphasic developmental cycle in which an infectious, extracellular form termed the elementary body (EB) interconverts with a metabolically active intracellular reticulate body (RB) within host cells. Subsets of genes are differentially expressed during the developmental cycle, and these genes are believed to be responsible for the transitions between the EB and RB forms. The goal of these studies was to explore two potential mechanisms that may function in regulating developmental cycle stage‑specific gene expression in chlamydiae: a cascade of sigma factor expression and the binding of the early stage protein …

A Behavioral And Anatomical Analysis Of Conditioned Taste Aversion In C57bl/6j And Dba/2j Mice, April Rebecca Glatt

Theses and Dissertations (ETD)

Conditioned taste aversion (CTA) has been commonly used as a model of learning and memory. Traditionally, CTA approaches have used a paradigm that follows the model of classical conditioning. This involves presentation of a novel tastant, such as sucrose (conditioned stimulus, CS), followed by an intraperitoneal injection of lithium chloride that induces gastric malaise (unconditioned stimulus, US), which results in the aversion of sucrose (conditioned response, CR). However, a more natural classical conditioning paradigm involves the consumption, rather than injection, of the US by using a self‑administration paradigm that allows for time‑dependent analysis of formation, generalization, and extinction of CTA …

The Design And Synthesis Of Autotaxin Inhibitors And Analogs Of Lysophosphatidic Acid, Renuka Niranjan Gupte

Theses and Dissertations (ETD)

Lysophosphatidic acid (LPA) is a naturally occurring bioactive phospholipid. It has a wide array of biological effects like cell proliferation, survival, migration, apoptosis invasion, wound healing and angiogenesis. Autotaxin (ATX) was identified as an autocrine tumor cell motility factor from A2058 melanoma conditioned medium. ATX has lysophospholipase D enzyme activity and is responsible for the cleavage of lysophophatidylcholine (LPC) leading to the generation of LPA. Antagonists of Autotaxin would have a potential therapeutic application in cancer research. Chapter 1 is an introduction of LPA and autotaxin. It provides the background and significance of the research. Chapter 2 explores the synthesis …

Temporal And Aerodynamic Aspects Of Velopharyngeal Coarticulation: Effects Of Age, Gender And Vowel Height, Fadwa Khwaileh

Theses and Dissertations (ETD)

Previous studies on the normal patterns of velopharyngeal coarticulation did not provide a multidimensional description of the phenomenon. The primary objective of this study was to determine the effects of age, gender and vowel height on the temporal and aerodynamic aspects of nasal airflow segments related to velar coarticulation in the normal speech of children and adults. A secondary objective was to determine the within speaker variability of the segments.

Speakers consisted of 20 children between the ages of 5 and 7 years, 20 children between 9 and 11 years and 20 adult speakers 18 years or older. Nasal and …

The Relationship Between Lower Extremity Bone Mass And Body Mass Index In A Nhanes Adolescent Population, James Randall Post

Theses and Dissertations (ETD)

The effect of body mass index (BMI) on bone mineral content (BMC) among adolescents has been researched yielding mixed results. This study explored the relationship of left lower extremity (LLE) BMC on BMI across the spectrum of weight in a large nationally representative group of adolescents. This descriptive study used secondary data from the publically accessible, cross-sectional survey files of the 1999-2004 Continuous National Health Assessment and Nutritional Examination Survey (NHANES) that contained whole body dual energy X‑ray absorptiometry (DXA) data as well as BMI calculations looking at the adolescent population 12- to19-year-olds at the time of the exam. The …