Digital Commons Network^™

Xenobiotic Metabolism Genes And Clubfoot, Amy M. Sommer

Dissertations and Theses (Open Access)

Idiopathic or isolated clubfoot is a common orthopedic birth defect that affects approximately 135,000 children worldwide. It is characterized by equinus, varus and adductus deformities of the ankle and foot. Correction of clubfoot involves months of serial manipulations, castings and bracing, with surgical correction needed in forty percent of cases. Multifactorial etiology has been suggested in numerous studies with both environmental and genetic factors playing an etiologic role. Maternal smoking during pregnancy is the only common environmental factor that has consistently been shown to increase the risk for clubfoot. Moreover, a positive family history of clubfoot and maternal smoking increases …

Validation Of The Activation Of Aurora B Kinase By Caenorhabditis Elegans To Usled-Like Kinase And The Identification Of Cyclin B3 As A Phospho-Specific Tlk-1 Interactor, Gary Michael Deyter

Dissertations and Theses (Open Access)

A hallmark of tumorigenesis and certain birth defect syndromes is the loss of ploidy that can result from incorrect chromosome segregation. Chromosomes that are not partitioned properly during mitosis are often fragmented, changing the genetic makeup of daughter cells. Inheriting extrachromosomal fragments that contain cell survival genes or losing chromosomal loci that encode tumor suppressors can promote tumor development. Thus, it is essential to elucidate molecular mechanisms required for correct chromosome segregation. Chromosomes are connected to mitotic spindle microtubules by way of a proteinacous, chromosome-bound organelle called the kinetochore. Two decades of research have confirmed that the conserved Aurora B/AIR-2 …

The Role Of A2b Adenosine Receptor Signaling In Adenosine Dependent Lung Disease, Yang Zhou

Dissertations and Theses (Open Access)

Chronic lung diseases and acute lung injuries are two distinctive pulmonary disorders that result in significant morbidity and mortality. Adenosine is a signaling nucleoside generated in response to injury and can serve both protective and destructive functions in tissues and cells through interaction with four G-protein coupled adenosine receptors: A1R, A2AR, A2BR, and A3R. However, the relationship between these factors is poorly understood. Recent findings suggest the A2BR has been implicated in the regulation of both chronic lung disease and acute lung injury. The work presented in this dissertation utilized the adenosine deaminase-deficient mouse model and the bleomycin-induced pulmonary injury …

Delta Like Ligand 4 Is A Critical Regulator Of Bone Marrow Cell Differentiation Into Pericytes/Vascular Smooth Muscle Cells And Is Essential For The Vasculogenesis That Supports The Growth Of Ewing’S Sarcoma, Keri L. Stewart

Dissertations and Theses (Open Access)

We have previously shown that vasculogenesis, the process by which bone marrow-derived cells are recruited to the tumor and organized to form a blood vessel network de novo, is essential for the growth of Ewing’s sarcoma. We further demonstrated that these bone marrow cells differentiate into pericytes/vascular smooth muscle cells(vSMC) and contribute to the formation of the functional vascular network. The molecular mechanisms that control bone marrow cell differentiation into pericytes/vSMC in Ewing’s sarcoma are poorly understood. Here, we demonstrate that the Notch ligand Delta like ligand 4 (DLL4) plays a critical role in this process. DLL4 is essential for …

Efficacy And Mechanism Of Â-Defensin2 Fused Antigen Protein Vaccines, Hyun J. Park

Dissertations and Theses (Open Access)

Vaccines which use the strategy of fusing adjuvant murine â-defensin2 (mBD2) to an antigen in order to elicit stronger anti-antigen immune responses are referred to as murine â-defensin2 (mBD2) vaccines. Previous studies have validated the potential of mBD2 vaccines, thus in this study we focus on increasing vaccine efficacy as well as mechanism elucidation. Initially, we demonstrate superior IFN-ã release levels by antigen specific effector T cells when antigen is crosspresented by dendritic cells (DC) which absorbed mBD2 vaccine (mBD2 fused antigen protein) over antigen alone. We move unto an in vivo model and note significant increases in the expansion …

Commissioning An Anthropomorphic Spine And Lung Phantom For Remote Dose Verification Of Institutions Participating In Rtog 0631, Douglas F. Caruthers

Dissertations and Theses (Open Access)

The RPC developed a new phantom to ensure comparable and consistent radiation administration in spinal radiosurgery clinical trials. This study assessed the phantom’s dosimetric and anatomic utility. The ‘spine phantom’ is a water filled thorax with anatomy encountered in spinal radiosurgery: target volume, vertebral column, spinal canal, esophagus, heart, and lungs. The dose to the target volume was measured with axial and sagittal planes of radiochromic film and thermoluminescent dosimeters (TLD). The dose distributions were measured with the radiochromic film calibrated to the absolute dose measured by the TLD. Four irradiations were administered: a four angle box plan, a seven …

Range Adaptive Proton Therapy For Prostate Cancer, Adam D. Melancon

Dissertations and Theses (Open Access)

Purpose: The rapid distal falloff of a proton beam allows for sparing of normal tissues distal to the target. However proton beams that aim directly towards critical structures are avoided due to concerns of range uncertainties, such as CT number conversion and anatomy variations. We propose to eliminate range uncertainty and enable prostate treatment with a single anterior beam by detecting the proton’s range at the prostate-rectal interface and adaptively adjusting the range in vivo and in real-time.

Materials and Methods: A prototype device, consisting of an endorectal liquid scintillation detector and dual-inverted Lucite wedges for range compensation, was designed …

Il-2 Regulation Of Il-24 Expression Leads To Growth Suppression Of Melanoma Cells, Emily Jen

Dissertations and Theses (Open Access)

Melanoma is known to be highly resistant to chemotherapy. Treatment with high dose IL-2 has shown significant clinical benefit in a minority of metastatic melanoma patients and has lead to long term survival in a few cases. However, this treatment is associated with excessive multiorgan toxicities, which severely limits its use. We hypothesize that one mechanism of effective IL-2 therapy is through the direct upregulation of IL-24 production in melanoma tumors and subsequent IL-24 mediated tumor growth suppression.

Five melanoma cell lines were treated with high dose recombinant hIL-2 at 1000U/ml. Three of the cell lines (A375, WM1341, WM793) showed …

First Trimester Screening And Its Impact On Uptake Of Diagnostic Testing, Deanna Darnes

Dissertations and Theses (Open Access)

Introduction: First Trimester Screening (FTS) combines maternal age with fetal nuchal translucency (NT) and maternal analytes to identify pregnancies at an increased risk for Down syndrome and trisomy 18. Though the accuracy of this screening is high, it cannot replace the conclusive accuracy of prenatal diagnostic testing (PDT). Since FTS has been available, a decrease in the number of women who pursue PDT has been observed. This study sought to determine if there has been a significant change in the amount of PDT performed in our clinics, if the type of FTS result affects the patient’s decision regarding PDT, and …

Xenoestrogen-Specific Mechanisms Of Developmental Reprogramming Correlate With Gene Expression And Tumor Development, Kristen L. Greathouse

Dissertations and Theses (Open Access)

Environmental exposures during sensitive windows of development can reprogram normal physiological responses and alter disease susceptibility later in life in a process known as developmental reprogramming. We have shown that neonatal exposure to the xenoestrogen diethylstilbestrol (DES) can developmentally reprogram the reproductive tract in genetically susceptible Eker rats giving rise to complete penetrance of uterine leiomyoma. Based on this, we hypothesized that xenoestrogens, including genistein (GEN) and bisphenol A (BPA), reprogram estrogen-responsive gene expression in the myometrium and promote the development of uterine leiomyoma. We proposed the mechanism that is responsible for the developmental reprogramming of gene expression was through …

Targeted Inhibition Of Sp1 Transcription Factor And Anti-Angiogenesis Of Human Pancreatic Cancer, Zhiliang Jia

Dissertations and Theses (Open Access)

Transcription factor Specificity Protein 1(Sp1) is reported to be essential for vascular endothelial growth factor (VEGF) constitutive expression in human pancreatic adenocarcinoma. The definitive role of Sp1 in angiogenesis, the impact of anti-angiogenic therapy on the Sp1/ VEGF signaling and the Sp1 signaling alteration on the anti-angiogenic therapy effect are unclear. The understanding of Sp1 regulation on VEGF and their interactions has significant clinical implications. Sp1 and VEGF expression and microvessel density (MVD) were analyzed using pancreatic cancer patients specimens through immunohistochemistry staining. The impact of Sp1 expression alternation on angiogenesis and tumor progression in nude mice were determined by …

Preeclampsia, Autoimmunity And The At1 Receptor, Roxanna A. Irani

Dissertations and Theses (Open Access)

Preeclampsia (PE) is a disease of late pregnancy characterized by maternal hypertension and proteinuria. It is associated with preterm delivery and significant perinatal morbidity and mortality. Despite affecting ~7% of first pregnancies, there is no effective screening method to identify women at risk, nor is there a definitive treatment other than delivery of the baby and placenta. Though the pathogenesis of PE remains unclear, an imbalance in the renin-angiotensin and immune systems are thought to be major contributors. Bridging these two concepts, it has recently been shown that women with PE harbor specific autoantibodies: the angiotensin II type 1 receptor …

Analysis Of Variation In Clubfoot Candidate Genes, Audrey R. Ester

Dissertations and Theses (Open Access)

Isolated clubfoot, a common birth defect occurring in more than 135,000 livebirths worldwide each year, is associated with significant health care and financial burdens. Clubfoot is defined by forefoot adduction, hindfoot varus, midfoot cavus and hindfoot equinus. Isolated clubfoot, which is the focus of these studies, is distinct from syndromic clubfoot because there are no other associated malformations. Population, family, twin and segregation analysis studies provide evidence that genetic and environmental factors play an etiologic role in isolated clubfoot. The studies described in this thesis were performed to define the role of genetic variation in isolated clubfoot. Interrogation of a …

Damage-Induced Inflammation And Nociceptive Hypersensitivity In Drosophila Larvae, Daniel T. Babcock

Dissertations and Theses (Open Access)

Mounting an effective response to tissue damage requires a concerted effort from a number of systems, including both the immune and nervous systems. Immune-responsive blood cells fight infection and clear debris from damaged tissues, and specialized pain receptors become hypersensitive to promote behavior that protects the damaged area while it heals. To uncover the cellular and molecular mechanisms underlying these processes, we have developed a genetically tractable invertebrate model of damage-induced inflammation and pain hypersensitivity using Drosophila larvae.

To study wound-induced inflammation, we generated transgenic larvae with fluorescent epidermal cells and blood cells (hemocytes). Using live imaging, we monitored the …

The Role Of Map Kinases On The Functional Heterogeneity Of Human Cd8+ T Cell Maturation Subsets, Tae Kon Kim

Dissertations and Theses (Open Access)

While prior studies have focused on naïve (CD45RA+CD27+) and early stage memory (CD45RA-CD27+) CD8+ T cells, late memory CD8+ T cells (CD45RA+CD27) have received less interest because this subset of T cells is generally recognized as effectors, which produce IFNγ (but no IL-2) and perforin. However, multiple studies suggest that late memory CD8+ T cells may provide inadequate protection in infectious diseases and cancer models.

To better understand the unique function of late memory CD8+ T cells, I optimized multi-color flow cytometry techniques to assess the cytokine production of each human CD8+ T cell maturation subset. I demonstrated that late …

Role Of Dopamine Of Nucleus Accumbens In Behavioral Sensitization To Methylphenidate, Sheshali J. Wanchoo

Dissertations and Theses (Open Access)

Behavioral sensitization is defined as the subsequent augmentation of the locomotor response to a drug following repeated administrations of the drug. It is believed to occur due to alterations in the motive circuit in the brain by stressors, central nervous system stimulants, and similar stimuli. The motive circuit (or mesocorticolimbic system) consists of several interconnected nuclei that determine the behavioral response to significant biological stimuli. A final target of the mesocorticolimbic system is the nucleus accumbens (NAc), which is a key structure linking motivation and action. In particular, the dopaminergic innervations of the Nac are considered to be essential in …

Gsk3 Mediates Signaling Upstream Of Akt, Debra L. Smith

Dissertations and Theses (Open Access)

The phosphatidylinositide 3 kinase (PI3K)/Akt signaling network plays a pivotal role in multiple cellular functions. PI3K links the extracellular growth factor receptors to the serine-threonine kinase Akt which, through phosphorylation of numerous intracellular proteins, mediates increased cell growth, survival, motility and proliferation. The significance of the PI3K/Akt signaling network to human malignancy is demonstrated by cancer-associated genetic aberrations at multiple levels in the PI3K/Akt pathway in many tumor lineages. These aberrations include mutation or amplification of Akt, catalytic and regulatory subunits of PI3K, and growth factor receptors upstream of PI3K. Inactivating mutations and decreased expression of the PTEN, a major …

Myogenin Modulates Exercise Endurance By Altering Skeletal Muscle Metabolism, James Eric Meadows

Dissertations and Theses (Open Access)

The function of myogenic regulatory factors (MRFs) during adult life is not well understood. The requirement of one of these MRFs, myogenin (Myog), during embryonic muscle development suggests an equally important role in adult muscle. In this study, we have determined the function of myogenin during adult life using a conditional allele of Myog. In contrast to embryonic development, myogenin is not required for adult viability, and Myog-deleted mice exhibited no remarkable phenotypic changes during sedentary life. Remarkably, sedentary Myog-deleted mice demonstrated enhanced exercise endurance during involuntary treadmill running. Altered blood glucose and lactate levels in sedentary Myog-deleted mice after …

Signaling Mechanisms That Control Gap Junctional Coupling Between Retinal Neurons, Wade Kothmann

Dissertations and Theses (Open Access)

Gap junctions between neurons form the structural substrate for electrical synapses. Connexin 36 (Cx36, and its non-mammalian ortholog connexin 35) is the major neuronal gap junction protein in the central nervous system (CNS), and contributes to several important neuronal functions including neuronal synchronization, signal averaging, network oscillations, and motor learning. Connexin 36 is strongly expressed in the retina, where it is an obligatory component of the high-sensitivity rod photoreceptor pathway. A fundamental requirement of the retina is to adapt to broadly varying inputs in order to maintain a dynamic range of signaling output. Modulation of the strength of electrical coupling …

Smooth Muscle Hyperplasia Due To Acta2/Myh11 Mutations: Identification Of Novel Pathology And Pathways Leading To Aneurysms And Diverse Vascular Occlusive Diseases, Christina L. Papke

Dissertations and Theses (Open Access)

Missense mutations in smooth muscle cell (SMC) specific ACTA2 (á-actin) and MYH11 (â-myosin heavy chain) cause diffuse and diverse vascular diseases, including thoracic aortic aneurysms and dissections (TAAD) and early onset coronary artery disease and stroke. The mechanism by which these mutations lead to dilatation of some arteries but occlusion of others is unknown. We hypothesized that the mutations act through two distinct mechanisms to cause varied vascular diseases: a loss of function, leading to decreased SMC contraction and aneurysms, and a gain of function, leading to increased SMC proliferation and occlusive disease. To test this hypothesis, ACTA2 mutant SMCs …

A New Tumor Suppressor Gene Candidate Regulated By The Non-Coding Rna Pca3 In Human Prostate Cancer, Alessandro K. Lee

Dissertations and Theses (Open Access)

Prostate cancer is the second leading cause of cancer-related death and the most common non-skin cancer in men in the USA. Considerable advancements in the practice of medicine have allowed a significant improvement in the diagnosis and treatment of this disease and, in recent years, both incidence and mortality rates have been slightly declining. However, it is still estimated that 1 man in 6 will be diagnosed with prostate cancer during his lifetime, and 1 man in 35 will die of the disease.

In order to identify novel strategies and effective therapeutic approaches in the fight against prostate cancer, it …

The Consequences Of Disrupting The Mdm2-P53 Balance In Hematopoiesis, Hussein A. Abbas

Dissertations and Theses (Open Access)

The bone marrow accommodates hematopoietic stem cells and progenitors. These cells provide an indispensible resource for replenishing the blood constituents throughout an organism’s life. A tissue with such a high turn-over rate mandates intact cycling checkpoint and apoptotic pathways to avoid inappropriate cell proliferation and ultimately the development of leukemias. p53, a major tumor suppressor, is a transcription factor that regulates cell cycle, and induces apoptosis and senescence. Mice inheriting a hypomorphic p53 allele in the absence of Mdm2, a p53 inhibitor, have elevated p53 cell cycle activity and die by postnatal day 13 due to hematopoietic failure. Hematopoiesis progresses …

Survival Prediction For Brain Tumor Patients Using Gene Expression Data, Vinicius Bonato

Dissertations and Theses (Open Access)

Brain tumor is one of the most aggressive types of cancer in humans, with an estimated median survival time of 12 months and only 4% of the patients surviving more than 5 years after disease diagnosis. Until recently, brain tumor prognosis has been based only on clinical information such as tumor grade and patient age, but there are reports indicating that molecular profiling of gliomas can reveal subgroups of patients with distinct survival rates. We hypothesize that coupling molecular profiling of brain tumors with clinical information might improve predictions of patient survival time and, consequently, better guide future treatment decisions. …

Eye Movement Measures Of Cognitive Control In Children With To Urette Syndrome, Cameron B. Jeter

Dissertations and Theses (Open Access)

Tourette Syndrome begins in childhood and is characterized by uncontrollable repetitive actions like neck craning or hopping and noises such as sniffing or chirping. Worst in early adolescence, these tics wax and wane in severity and occur in bouts unpredictably, often drawing unwanted attention from bystanders. Making matters worse, over half of children with Tourette Syndrome also suffer from comorbid, or concurrent, disorders such as attention deficit hyperactivity disorder (ADHD) and obsessive-compulsive disorder (OCD). These disorders introduce anxious thoughts, impulsivity, inattention, and mood variability that further disrupt children with Tourette Syndrome from focusing and performing well at school and home. …

Host-Pathogen Interactions Of Secreted And Surface Staphylococcus Aureus Factors, Vanessa Vazquez

Dissertations and Theses (Open Access)

Staphylococcus aureus is an opportunistic bacterial pathogen that can infect humans and other species. It utilizes an arsenal of virulence factors to cause disease, including secreted and cell wall anchored factors. Secreted toxins attack host cells, and pore-forming toxins destroy target cells by causing cell lysis. S. aureus uses cell-surface adhesins to attach to host molecules thereby facilitating host colonization. The Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) are a family of cell-wall anchored proteins that target molecules like fibronectin and fibrinogen. The Serine-aspartate repeat (Sdr) proteins are a subset of staphylococcal MSCRAMMs that share similar domain organization. Interestingly, …

The Role Of Mucosal Epithelial Cells In Hiv-1 Infection, Danielle Fontenot

Dissertations and Theses (Open Access)

The predominant route of human immunodeficiency virus type 1 (HIV-1) transmission is infection across the vaginal mucosa. Epithelial cells, which form the primary barrier of protection against pathogens, are the first cell type at these mucosal tissues to encounter the virus but their role in HIV infection has not been clearly elucidated. Although mucosal epithelial cells express only low levels of the receptors required for successful HIV infection, productive infection does occur at these sites. The present work provides evidence to show that HIV exposure, without the need for productive infection, induces human cervical epithelial cells to produce Thymic Stromal …

Thoracic Radiotherapy Treatment Planning With Cine Pet/Ct, Adam C. Riegel

Dissertations and Theses (Open Access)

Purpose: Respiratory motion causes substantial uncertainty in radiotherapy treatment planning. Four-dimensional computed tomography (4D-CT) is a useful tool to image tumor motion during normal respiration. Treatment margins can be reduced by targeting the motion path of the tumor. The expense and complexity of 4D-CT, however, may be cost-prohibitive at some facilities. We developed an image processing technique to produce images from cine CT that contain significant motion information without 4D-CT. The purpose of this work was to compare cine CT and 4D-CT for the purposes of target delineation and dose calculation, and to explore the role of PET in target …

Mechanism-Based Strategies To Enhance The Actions Of A, Fabiola C. Gomez

Dissertations and Theses (Open Access)

Heat shock protein 90 (HSP90) is an abundant molecular chaperone that regulates the functional stability of client oncoproteins, such as STAT3, Raf-1 and Akt, which play a role in the survival of malignant cells. The chaperone function of HSP90 is driven by the binding and hydrolysis of ATP. The geldanamycin analog, 17-AAG, binds to the ATP pocket of HSP90 leading to the degradation of client proteins. However, treatment with 17-AAG results in the elevation of the levels of antiapoptotic proteins HSP70 and HSP27, which may lead to cell death resistance. The increase in HSP70 and HSP27 protein levels is due …

Ampa Receptor Allosterism: Measurement Of The Conformational Changes In The Ligand Binding Domain Of A Functional Receptor, Jennifer Gonzalez-Mcgehee

Dissertations and Theses (Open Access)

Ionotropic glutamate receptors are important excitatory neurotransmitter receptors in the mammalian central nervous system that have been implicated in a number of neuropathologies such as epilepsy, ischemia, and amyotrophic lateral sclerosis. Glutamate binding to an extracellular ligand binding domain initiates a series of structural changes that leads to the formation of a cation selective transmembrane channel, which consequently closes due to desensitization of the receptor. The crystal structures of the AMPA subtype of the glutamate receptor have been particularly useful in providing initial insight into the conformational changes in the ligand binding domain; however, these structures are limited by crystallographic …

Type I Insulin-Like Growth Factor Receptor Tyrosine Kinase As A Molecular Target In Mantle Cell Lymphoma, Deeksha Vishwamitra

Dissertations and Theses (Open Access)

Mantle cell lymphoma (MCL) is an aggressive B-cell lymphoid malignancy representing 5-10% of all non-Hodgkin’s lymphomas. It is distinguished by the t(11;14)(q13;q32) chromosomal translocation that juxtaposes the proto-oncogene CCND1, which encodes cyclin D1 at 11q13 to the IgH gene at 14q32. MCL patients represent about 6% of all new cases of Non-Hodgkin’s lymphomas per year or about 3,500 new cases per year. MCL occurs more frequently in older adults – the average age at diagnosis is the mid-60s with a male-to-female ratio of 2-3:1. It is typically characterized by the proliferation of neoplastic B-lymphocytes in the mantle zone of the …