Medicine and Health Sciences Commons^™

Involvement Of Signal Peptidase I In Streptococcus Sanguinis Biofilm Formation, Jessica Aynapudi

Theses and Dissertations

Biofilm accounts for 65%-80% of microbial infections in humans. Considerable evidence links biofilm formation to oral disease and consequently systemic infections. Eradication of biofilm-associated infections is important. Streptococcus sanguinis, a Gram-positive bacterium, is one of the most abundant species in oral biofilm. It contributes to biofilm development in oral cavities and is one of the recognized causes of infective endocarditis. To study and identify biofilm genes in S. sanguinis, biofilm formation of 51 mutants was compared with the wild type SK36 strain using crystal violet (CV) staining in a microtiter plate. Confocal laser scanning microscopy (CLSM) and image analysis was …

The Role Of Enteric Glia In Opioid-Induced Constipation, Sukhada Bhave

Theses and Dissertations

Morphine is one of the most widely used drugs for the treatment of pain but its clinical efficacy is limited by adverse effects including persistent constipation and colonic inflammation. Morphine-induced colonic inflammation is facilitated by microbial dysbiosis and bacterial translocation. In this study, we demonstrate that secondary inflammation and persistent constipation are modulated by enteric glia. In chronic morphine treated mice (75 mg morphine pellet/5 days), ATP-induced currents were significantly enhanced in enteric glia isolated from the mouse colon myenteric plexus. Chronic morphine resulted in significant disruption of the colonic epithelium and increased Il-1β in the myenteric plexus. The increase …

Social Determinants Of Participation In A Home Visitation Fluoride Varnish Program, James E. Puryear, Tegwyn Brickhouse, Caroline Carrico

Theses and Dissertations

Purpose: The purpose of this study is to examine the social determinants of CHIP (Child Health Investment Partnership) of Roanoke Valley children who participated in the preventive oral health program compared to those who did not.

Methods: This is a retrospective cohort study of children (n=2,425) enrolled in CHIP of Roanoke Valley from September 2008-September 2014. Bivariate analysis and multivariable logistic regression models were used to compare age, gender, race, locality, parents’ education level, age at enrollment, and length of enrollment for oral health program participants versus those who did not participate.

Results: Children who were Hispanic …

Quantitative Analysis Of 5-Chloro-2-Methoxy-N-[2-(4-Sulfamoylphenyl)Ethyl]Benzamide (Glyburide Analogue, Ga) In Mouse Plasma And Whole Blood Using A Micro-Extraction And Liquid Chromatography-Tandem Mass Spectrometry, Ankit Zalavadia

Theses and Dissertations

Pharmacokinetic evaluation of 5-chloro-2-methoxy-N-[2-(4- sulfamoylphenyl)ethyl]benzamide in mouse plasma demanded for a suitable bioanalytical method. No reported bioanalytical method exists to-date that can quantify concentration of this compound in any biological matrix. The purpose of this study was 1) to develop and validate a new bioanalytical method using a micro-extraction and LC-MS/MS to quantify the target analyte in mouse plasma and 2) to partially validate the method in whole blood. A bioanalytical method was developed and validated in both matrices for a linear concentration range of 2-1000 ng/ml. For both matrices, the reverse predicted concentration of calibration standards (-8.95% to 12.16% …

Power Analysis In Applied Linear Regression For Cell Type-Specific Differential Expression Detection, Edmund Glass

Theses and Dissertations

The goal of many human disease-oriented studies is to detect molecular mechanisms different between healthy controls and patients. Yet, commonly used gene expression measurements from any tissues suffer from variability of cell composition. This variability hinders the detection of differentially expressed genes and is often ignored. However, this variability may actually be advantageous, as heterogeneous gene expression measurements coupled with cell counts may provide deeper insights into the gene expression differences on the cell type-specific level. Published computational methods use linear regression to estimate cell type-specific differential expression. Yet, they do not consider many artifacts hidden in high-dimensional gene expression …

Provision Of Hospital-Based Palliative Care And The Impact On Organizational And Patient Outcomes, Marisa L. Roczen

Theses and Dissertations

Hospital-based palliative care services aim to streamline medical care for patients with chronic and potentially life-limiting illnesses by focusing on individual patient needs, efficient use of hospital resources, and providing guidance for patients, patients’ families and clinical providers toward making optimal decisions concerning a patient’s care. This study examined the nature of palliative care provision in U.S. hospitals and its impact on selected organizational and patient outcomes, including hospital costs, length of stay, in-hospital mortality, and transfer to hospice. Hospital costs and length of stay are viewed as important economic indicators. Specifically, lower hospital costs may increase a hospital’s profit …

Cancer Health Literacy And Hospitalization In The First Five Years Following A Cancer Diagnosis, Laura A. Cartwright

Theses and Dissertations

BACKGROUND: The field of health literacy research has been focused recently on developing more accurate measurement tools and understanding the relationship between health literacy and health outcomes. Individuals with lower levels of health literacy have worse health outcomes, including hospitalization rates, compared to those with adequate health literacy. This relationship has yet to be examined in the cancer patient population, although significant relationships between health literacy and cancer knowledge, screening behavior and quality of life have been found. This study is the first to examine the relationship between health literacy and hospitalization rates in a cancer patient population, and the …

Probing Allosteric, Partial Inhibition Of Thrombin Using Novel Anticoagulants, Stephen S. Verespy Iii

Theses and Dissertations

Thrombin is the key protease that regulates hemostasis; the delicate balance between procoagulation and anticoagulation of blood. In clotting disorders, like deep vein thrombosis or pulmonary embolism, procoagulation is up-regulated, but propagation of clotting can be inhibited with drugs targeting the proteases involved, like thrombin. Such drugs however, have serious side effects (e.g., excessive bleeding) and some require monitoring during the course of treatment. The reason for these side effects is the mechanism by which the drugs’ act. The two major mechanisms are direct orthosteric and indirect allosteric inhibition, which will completely abolish the protease’s activity. Herein we sought an …

Understanding And Targeting The C-Terminal Binding Protein (Ctbp) Substrate-Binding Domain For Cancer Therapeutic Development, Benjamin L. Morris

Theses and Dissertations

Cancer involves the dysregulated proliferation and growth of cells throughout the body. C-terminal binding proteins (CtBP) 1 and 2 are transcriptional co-regulators upregulated in several cancers, including breast, colorectal, and ovarian tumors. CtBPs drive oncogenic properties, including migration, invasion, proliferation, and survival, in part through repression of tumor suppressor genes. CtBPs encode an intrinsic dehydrogenase activity, utilizing intracellular NADH concentrations and the substrate 4-methylthio-2-oxobutyric acid (MTOB), to regulate the recruitment of transcriptional regulatory complexes. High levels of MTOB inhibit CtBP dehydrogenase function and induce cytotoxicity among cancer cells in a CtBP-dependent manner. While encouraging, a good therapeutic would utilize >100-fold …

N-Methyl 4-Methyl Amphetamine N-Alkyl Chain Extension Differentially Affects Ion Flux At The Human Dopamine And Norepinephrine Transporters, Alan C. Harris Jr.

Theses and Dissertations

Amphetamine (AMPH) and its derivatives embody a remarkable breadth of pharmacology. These molecules exert their effects, both therapeutic and pathological, at the human monoamine transporters, which tune synaptic dynamics by evacuating monoamine neuromodulators from the synapse subsequent to neuronal impulses. These transporters are electrogenic, and the transporter-mediated current can be correlated to a surrogate measure of the change in membrane voltage: Ca⁺⁺ currents from co-transfected L-type Ca⁺⁺ channels. The present work makes use of this assay, with which it is possible to derive pharmacodynamic metrics from both substrates and inhibitors. This work presents data on a heretofore-unstudied class …

Pharmacological Implications Of Adenosine 2a Receptor- Dopamine Type 2 Receptor Heteromerization, Candice N. Hatcher-Solis

Theses and Dissertations

G protein-coupled receptors (GPCRs) are heptahelical, transmembrane proteins that mediate a plethora of physiological functions by binding ligands and releasing G proteins that interact with downstream effectors. GPCRs signal as monomers, complexes of the same receptor subtype (homomers), or complexes of different receptor subtypes (heteromers). Recently, heteromeric GPCR complexes have become attractive targets for drug development since they exhibit distinct signaling and cell-specific localization from their homomeric counterparts. Yet, the effect of heteromerization on the pharmacology of many GPCR homomers remains unknown. Therefore, we have undertaken the task to examine the effect of heteromerization on G_s signaling through the …

Predictors Of Caffeine-Related Withdrawal Symptoms In College Freshmen, David J. Pomm

Theses and Dissertations

While caffeine withdrawal has been well-characterized, research on caffeine intake and factors associated with withdrawal has been limited. The present study examined prevalence rates of caffeine use and identified psychosocial factors associated with having caffeine withdrawal headaches (CWH). Participants were N = 1,989 college freshmen who participated in the 2011 Spit for Science project. Caffeine use was reported by 80% of the sample. Females were more likely than males to consume caffeine, and soda was the primary source of caffeine for both genders. As hypothesized, daily caffeine users were more likely to report CWH than non-daily users. When multivariable analyses …

Continuous Stationary Phase Gradients For Planar And Column Chromatography, Veeren Dewoolkar

Theses and Dissertations

Surfaces that exhibit a gradual change in their chemical and/or physical properties are termed as surface gradients. Based on the changes in properties they are classified either as physical or chemical gradients. Chemical gradients show variations in properties like polarity, charge, functionality concentration and have found potential applications in fields of biology, physics, biosensing, catalysis and separation science. In this dissertation, surface gradients have been prepared using controlled rate infusion (CRI).

CRI is a simple method in which a surface gradient is formed by carrying out the infusion of organoalkoxysilane in a time-dependent fashion using a set infusion rate. Depending …

Stains Induce Apoptosis And Autophagy In Primary And Transformed Mast Cells, Patrick A. Paez

Theses and Dissertations

Statin drugs are widely employed in the clinic to reduce serum low density lipoproteins (LDLs) in patients with hypocholesteremia. In addition to their cholesterol-lowering effects through HMG CoA reductase antagonism, isoprenyl lipids necessary for membrane anchorage and signaling of small G-proteins are abrogated. We previously found that statins suppress mast cell activation in murine and human cells, suggesting these drugs might be useful in treating allergic disease. While mast cell function is critical to allergic inflammation, mast cell hyperplasia and survival also impact these diseases, and were not studied in our previous work. In this study, we describe Fluvastatin-mediated apoptosis …

Response Adaptive Randomization Using Surrogate And Primary Endpoints, Hui Wang

Theses and Dissertations

In recent years, adaptive designs in clinical trials have been attractive due to their efficiency and flexibility. Response adaptive randomization procedures in phase II or III clinical trials are proposed to appeal ethical concerns by skewing the probability of patient assignments based on the responses obtained thus far, so that more patients will be assigned to a superior treatment group. General response-adaptive randomizations usually assume that the primary endpoint can be obtained quickly after the treatment. However, in real clinical trials, the primary outcome is delayed, making it unusable for adaptation. Therefore, we utilize surrogate and primary endpoints simultaneously to …

Human Neural Progenitor Cells Are Productively Infected By R5-Tropic Hiv-1: Opiate Interactions On Infection And Function Involve Cdk5 Signaling, Joyce Magat Balinang

Theses and Dissertations

Human immunodeficiency virus type 1 (HIV-1) is known to cause a spectrum of neurological, behavioral and motor deficits collectively termed as HIV-1 associated neurocognitive impairments (HAND). Opiates augment HIV-related CNS complications through both direct and indirect mechanisms that disrupt glial and neuronal function. All CNS macroglia and neurons derive from neural progenitor cells (NPCs) during development, and NPCs in the adult brain contribute to repair processes. Since disruptions in NPC function are known to impact CNS populations and brain function in a number of disease/injury conditions, we determined whether HIV ± opiate exposure affected the maturation and fate of human …

Behaviorally Induced Insufficient Sleep Syndrome And Insomnia: Prevalence And Relationship To Depression In College Students, Allison Baylor

Theses and Dissertations

Background: College students are at increased risk for general sleep issues as well as specific disorders, including Behaviorally Induced Insufficient Sleep Syndrome (BISS) and insomnia. These disorders can have deleterious daytime consequences, which can be compounded by exacerbating depression. The present study aims to establish college prevalence of BISS/insomnia, to characterize sleep characteristics in this sample, and to compare depression across BISS/insomnia.

Methods: Data from a college risk behaviors and health study (n=989) was used. Insomnia and BISS were defined as mutually exclusive disorders, using ICD-10/DSM-5 criteria, and Pittsburg Sleep Quality Index items.

Results: Overall, the results of this study …

Genetic And Epigenetic Mechanisms Of Complex Reproductive Disorders, Bhavi P. Modi

Theses and Dissertations

Common, complex disorders are polygenic and multifactorial traits representing interactions between environmental, genetic and epigenetic risk factors. More often than not, contributions of these risk factors have been studied individually and this is especially true for complex reproductive traits where application of genomic technologies has been challenging and slow to progress. This thesis explores the potential of genetic and epigenetic components contributing to a better understanding of the biological pathways underlying disease risk in two specific female complex reproductive traits - polycystic ovary syndrome (PCOS) and preterm premature rupture of membranes (PPROM). The PCOS projects focus on characterization of a …

Obesity And Asthma: Adiponectin Receptor 1 (Adipo R1) And Adiponectin Receptor 2 (Adipo R2) Are Expressed By Normal Human Bronchial Epithelial (Nhbe) Cells At Air-Liquid Interface (Ali) And Expression Changes With Il-13 Stimulation, Jennifer L. Bradley

Theses and Dissertations

Obesity is recognized as an important risk factor for the development of many chronic diseases such as hypertension, Type 2 diabetes mellitus (T2DM) cardiovascular disease, cancer, renal disease, neurologic dysfunction, metabolic syndrome and asthma (3, 4). Circulating serum adiponectin levels in obese asthmatics have been reported to be low. Therefore, we aimed to investigate the role of adiponectin in a mucus hypersecretion model and hypothesized that adiponectin would decrease IL-13 induced MUC5AC expression from differentiated NHBE cells and that increasing concentrations of IL-13 would cause a decrease in Adipo R1 and Adipo R2 expression. MUC5AC expression with exposure to adiponectin …

Resource Utilization And Costs Associated With Off-Label Use Of Atypical Antipsychotics In An Adult Population, Della Varghese

Theses and Dissertations

Introduction: Atypical Antipsychotics (AAPs) are approved by the Food and Drug Administration (FDA) for the treatment of schizophrenia and bipolar disorder. AAPs are commonly used off-label to treat depression, post-traumatic stress disorder and neuropsychiatric symptoms in dementia due to lack of alternative treatment options and treatment resistance. Concerns for off-label use arise since AAPs increase the risk of cardiovascular events and death. The objectives were 1) describe patterns of RU and costs among off-label AAPs users in a nationally representative population 2) identify prevalence of off-label use in the Medicare population 3) compare RU and costs between off-label AAPs …

Curcumin/Melatonin Hybrids As Neuroprotective Agents For Alzheimer's Disease, John Saathoff

Theses and Dissertations

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the leading cause of dementia, affecting ~5.2 million Americans. Current FDA approved medications provide mainly symptomatic relief and there are no agents available to delay or cure this disease. Multiple factors such as amyloid-β aggregates, dyshomeostasis of biometals, oxidative stress, and neuroinflammation have been implicated in the development of AD. Even though significant advances have been made in understanding the mechanisms leading to AD, the exact etiology still remains elusive. Given AD’s multifactorial nature, a multifunctional strategy of small molecule design would help to identify novel chemical templates. Recently our lab …

The Incidence Of Root Dentinal Micro-Cracks Caused By Reciprocating And Continuous Rotary Instrumentation, Stephen N. Schroeder

Theses and Dissertations

The aim of this study was to compare the incidence of root canal dentinal micro-cracks after canal instrumentation using reciprocating files (WaveOne Gold® and Twisted Adaptive®) and continuous rotation files (Edge Evolve® and EndoSequence®) in an ex-vivo benchtop study. This project used a novel methodology of finding dentinal defects using the “K-cube”, which allows evaluators to visualize sectioned root surfaces before instrumentation and after instrumentation. Mesial roots from 40 human mandibular first molars were divided into 4 groups of 10 for each file type. Root section pictures were taken with a Zeiss Discovery V20 stereomicroscope before and after canal instrumentation. …

Prevalence, Incremental Cost And Resource Utilization Associated With Opioid Overdoses, Batul Electricwala

Theses and Dissertations

Background –

An increase in opioid prescribing has led to an increase in opioid overdoses.^1,2 No study has estimated the incremental costs subsequent to an opioid overdose event in prescription opioid users, or the prevalence and costs of overdose events in family members of prescription opioid users and in overdose victims with no identifiable source of prescription opioid. The latter group will be referred to as “others”.

Objectives –

The first objective of this study was to estimate the prevalence of opioid overdoses in aforementioned groups. The second objective was to estimate the incremental costs and resource utilization associated …

Emerging Pathogens In Cystic Fibrosis Patients At Virginia Commonwealth University Medical Center (Vcumc), Emily M. Hill

Theses and Dissertations

Cystic fibrosis (CF) is an autosomal recessive disorder affecting 70,000 individuals worldwide. This disease is characterized by the buildup of mucus in the airways leading to chronic lung infections resulting in pulmonary failure and death in 95% of CF patients. Routine surveillance of CF pathogens using traditional microbiology culture guides management and treatment of CF patients. Molecular profiling studies have revealed emerging pathogens that may play a role in CF lung disease by either directly causing infection or upregulating the virulence factors of classic CF pathogens, such as P. aeruginosa; however, routine CF culture protocols have not been modified …

Effects Of Traumatic Brain Injury On Oxycodone Reinstatement And Physical Dependence, Neil B. Varshneya

Theses and Dissertations

Epidemiological data indicate that patients who experience a traumatic brain injury (TBI) have an elevated risk of developing a substance use disorder (SUD), but the underlying neurobiological connections remain unclear. To further understand the relationship between TBI and SUD, we investigated the effects of TBI on the abuse-related effects of oxycodone in preclinical models. Our evaluation utilized a lateral fluid percussion injury of moderate severity in adult male Sprague-Dawley rats. In the first aim, we tested the hypothesis that moderate TBI increases the risk for relapse to an opioid use disorder as measured by reinstatement of lever-pressing behavior following extinction …

Resolution Of Inflammation Rescues Axon Initial Segment Disruption, Nicholas M. George

Theses and Dissertations

Axonal domains are required for proper neuron function. These domains are unstable and degenerate concurrent with the inflammation in multiple sclerosis (MS) and the inflammatory disease models experimental autoimmune encephalomyelitis (EAE) and lipopolysaccharide (LPS) induced inflammation. Previous studies from our laboratory have shown that the axon initial segment (AIS) is maintained independently of the presence of myelin, but that AIS disruption is seen in MS as well as EAE and LPS-mediated inflammation. AIS loss can be interrupted in the early stage of EAE using the anti-inflammatory drug Didox. However, the potential for Didox directed repair of the AIS in later …

Motives For Participation In Triathlons Among Midlife To Older Black Women: A Mixed Method Study, Candace Brown

Theses and Dissertations

BACKGROUND: Research has established the positive link between physical activity and its impact on health among adults. Generally, as people get older, they are less likely to be active. Black women comprise 13% of the women in the US but constitute 52% of women who are inactive. Existing articles on exercise motivation among Black women have generally assessed sedentary individuals. Little research has examined the motivations to exercise among physically active Black women. METHODS: Guided by the regulators of the Self Determination Theory, the 56 item Motivations of Marathoners Scales for Triathletes (MOMS-T) was used to assess the motives of …

Tumor-Specific Cell Death Induction By Noxa Overexpression For Head And Neck Squamous Cell Carcinoma (Hnscc) Treatment, Nicolas T. Maxim Mr.

Theses and Dissertations

The primary focus of this research is the mechanisms of cell death in head and neck squamous cell carcinoma (HNSCC) treatment. These cancers typically originate in squamous cells that line the moist mucosal surfaces of head and neck. HNSCC is commonly treated with a platinum based agent, cisplatin. While the drug does offer strong antitumor effects, its prolonged use often results in tumor-acquired resistance, which limits treatment effectiveness. We have shown that cisplatin treatment induces the expression of a pro-apoptotic BCL-2 family member Noxa, which then initiates caspase- dependent apoptosis through its binding and sequestration of pro-survival protein MCL-1 for …

Sulfated Dehydropolymer Of Caffeic Acid For Repair Of Lung Damage And Emphysema, Tien M. Truong

Theses and Dissertations

The complex pathobiologic mechanisms of emphysema are not fully understood, leaving this deadly disease without effective pharmacotherapy for a cure. This project hypothesized that the sulfated dehydropolymer of caffeic acid (CDSO3) exhibits Fe²⁺ chelation-based hypoxia inducible factor-1a (HIF-1a) up-regulatory protective activities against in vitro emphysematous cell death and for in vivo reversal of emphysema induced with SU5416, a vascular endothelial growth factor blocker.

Using in vitro chromogenic competitive inhibition assays, CDSO3 was shown to chelate Fe²⁺ (IC₅₀ of 23 µM), but not Fe³⁺ ions. The trypan blue exclusion and lactate

dehydrogenase assays were then employed to …

Examining Genetic And Environmental Influences On Alcohol Use And Externalizing Behaviors In African American Adolescents, Neeru Goyal

Theses and Dissertations

The aim of this thesis is to expand our understanding of the etiology of alcohol misuse and related disorders in African Americans using genetically informative study designs. Specifically, we take advantage of the candidate-gene approach and polygenic score analysis to extend the literature specific to African American populations. Chapter 2 explores gene x environment (GxE) interactions through the candidate gene approach to explore the relationship between two genes chosen on their potential relevance to stress response and adolescent alcohol use and misuse, among African American youth living in highly impoverished neighborhoods, as moderated by stressful life events. Chapter 3 implements …