Medical Sciences Commons^™

Embryonic Stem Cell Derived Exosomes Enhance Cardiac Stem Cell Differentiation Into Heart Cells, Jamillah Hammond

Electronic Theses and Dissertations

Transplantation of embryonic stem (ES) cells into the ischemic and infarcted heart has proven to repopulate cardiac cell populations, attenuate structural cardiac remodeling, and rescue cardiac function. Unfortunately, the pluripotency of ES cells increases risk of teratoma formation in vivo. Exosomes, smaller in comparison to ES cells, are cell free carriers of miRNA, proteins, and lipids, and do not suggest risk of teratoma formation. Exosomes have been proposed to mediate and attenuate regeneration following myocardial infarction (MI), however, the role of exosomes derived from ES cells (ES-Exo) in activating resident cardiac stem cells (CSCs) to undergo cardiac differentiation is not …

On The Future Of Antidepressant Treatments: Targeting Neurotrophic Factors And Plasticity, Stephen W. White

Electronic Theses and Dissertations

For 60-plus years the explanatory model for Major Depressive Disorder (MDD) has been the monoamine theory, which states that low levels of monoamine neurotransmitters or alterations in their post-synaptic receptors are responsible for depressive symptoms. Drugs designed to elevate synaptic monoamine levels have remained the first line of pharmacotherapy prescribed by clinicians for MDD patients. However, these drugs have shortcomings. Despite evidence that current antidepressants elevate synaptic monoamine levels within hours of administration, these drugs require four to six weeks of daily administration before symptom relief appears. Furthermore, approximately half of patients taking typical antidepressants never achieve full symptom relief. …

A Scale Space Local Binary Pattern (Sslbp) – Based Feature Extraction Framework To Detect Bones From Knee Mri Scans, Jinyeong Mun

Electronic Theses and Dissertations

The medical industry is currently working on a fully autonomous surgical system, which is considered a novel modality to go beyond technical limitations of conventional surgery. In order to apply an autonomous surgical system to knees, one of the primarily responsible areas for supporting the total weight of human body, accurate segmentation of bones from knee Magnetic Resonance Imaging (MRI) scans plays a crucial role. In this paper, we propose employing the Scale Space Local Binary Pattern (SSLBP) feature extraction, a variant of local binary pattern extractions, for detecting bones from knee images. The proposed methods consist of two phases. …

Neuromuscular Junction Defects In A Mouse Model Of Charcot-Marie-Tooth Disease Type 2o, Thywill Sabblah

Electronic Theses and Dissertations

Charcot Marie Tooth disease (CMT) represents the most common inheritable peripheral group of motor and sensory disorders; affecting 1 in 2500 people worldwide. Individuals with CMT experience slow progressing weakness of the muscle, atrophy, mild loss of motor coordination and in some cases loss of sensory function in the hands and feet which could ultimately affect mobility. Dynein is an essential molecular motor that functions to transport cargos in all cells. A point mutation in the dynein heavy chain was discovered to cause CMT disease in humans, specifically CMT type 2O. We generated a knock-in mouse model bearing the same …

Role Of Mycobacterium Avium Paratuberculosis (Map) And Tnfsf15 Snps On Tl1a In Cd, Sayf Al-Deen Hassouneh

Electronic Theses and Dissertations

Tumor Necrosis Factor-Like Ligand 1a (TL1A) is a cytokine encoded by Tumor Necrosis Factor Super Family 15 gene (TNFSF15) gene mostly in endothelial cells which binds to T-cells and foments the production of pro-inflammatory cytokines including TNF-α, IL-6, IL-1b, IFN- γ and IL-13. TL1A level is elevated in inflammatory diseases including Crohn's Disease (CD). Although Single Nucleotide Polymorphisms (SNPs) in TNFSF15 have been reported in CD, no studies have investigated the effect of these SNPs on TL1A, inflammation, and susceptibility to Mycobacterium avium subspecies paratuberculosis (MAP) infection. MAP is a strong candidate in CD pathogenesis. This study is designed to …

Exacerbation Of Δefp Sickness In Escherichia Coli By An Uncharacterized Rna Helicase, Robert Wingo

Electronic Theses and Dissertations

In Escherichia coli, growth is rate-limited by translation capacity [1]. Stalled ribosomes have profound effects on a cell such as altered mRNA abundance, decreased ribosome availability, and an imbalanced proteome. The absence of elongation factor P (EF-P), a universally conserved transpeptidation enhancer, presents an extreme example of this scenario, wherein ribosomes accumulate disproportionately onto messages that are more slowly translated and cell growth becomes notably impaired. We discovered that faster-growing cells arise spontaneously in Δefp cultures, suggesting that translation defects could be circumvented by mutating other genes. This thesis presents a genetic and biochemical analysis of a mechanism Δefp cells …

Metabolic Regulation Of Myocardial Adaptation To Exercise., Andrew Alan Gibb

Electronic Theses and Dissertations

While the benefits of exercise affect several organs, a significant adaptive response occurs within the heart. Exercise promotes cardiac growth, increases angiogenesis, and enhances cardiac function and these adaptations are associated with a cardioprotective phenotype. Additionally, extensive evidence shows that exercise dynamically regulates myocardial metabolism. This can be attributed to both changes in hormonal stimulation, increases in bioenergetic demand, and the bioavailability of circulating substrates. However, it is unclear whether these changes in metabolism contribute to physiologic cardiac growth. We reason that exercise-induced changes in metabolism are required to balance the catabolic and anabolic reactions needed for growth. Specifically, we …

The Role Of Hif-1Α In Intestinal Epithelial Barrier Function In Alcoholic Liver Disease., Tuo Shao

Electronic Theses and Dissertations

Hypoxia inducible factor 1 α (HIF1α) is an oxygen-responsive subunit. HIF-1α plays a pivotal role in many pathophysiological processes. In addition to oxygen availability, HIF-1α can be regulated by multiple other factors in response to various pathophysiological processes. Previous studies showed that hepatic HIF-1α could be beneficial or harmful in experimental alcoholic liver disease (ALD). However, the role of intestinal HIF-1α in ALD has not yet been studied. Given the critical role of the gut-liver axis in ALD, it is important to elucidate the role of intestinal epithelial HIF-1α in ALD. In the first chapter, we used wide type (WT) …

Ubqln1 : A Multi-Domain Protein With Multiple Functions., Zimple Kurlawala

Electronic Theses and Dissertations

There are 5 Ubiquilin proteins (UBQLN1-4, UBQLN-L), which are evolutionarily conserved and structurally similar. UBQLN proteins have 3 functional domains: N-terminal ubiquitin-like domain (UBL), C-terminal ubiquitin-associated domain (UBA) and STI chaperone-like regions in the middle. Alterations in UBQLN1 gene have been detected in a variety of disorders including Alzheimer’s disease, Amyotropic Lateral Sclerosis and lung cancer. UBQLN1 has been largely studied in neurodegenerative disorders in the context of protein quality control. Several studies have hypothesized that the UBA domain of UBQLN1 binds to poly-ubiquitin chains of substrate and shuttles it to the proteasome via its UBL domain for degradation. UBQLN1 …

Revisiting Neutrophil Responses To Toll-Like Receptor 4 : Influence Of Ligand Structures And Cellular Environments., Shuvasree Sengupta

Electronic Theses and Dissertations

Neutrophils respond to bacterial LPS through Toll-like receptor 4 (TLR4), which activates or potentiates immune defensive functions and prolongs cell survival. Activation of TLR4 signaling in neutrophils is beneficial for effective clearance of LPS-bearing Gram-negative bacteria, but may also drive aberrant inflammation if not stringently regulated. The regulatory processes by which neutrophil functions are calibrated to respond appropriately to different LPS-bearing bacteria are incompletely understood. Described here are investigations that reveal an unexpected sensitivity of TLR4 in neutrophils to small changes in LPS structure typical of various Gram-negative bacteria, including those that are dangerously virulent (Escherichia coli and Salmonella …

Trunk And Respiratory Motor Control In Typically Developing Children And Its Implications In Children With Chronic Spinal Cord Injury., Goutam Singh

Electronic Theses and Dissertations

Independent sitting is a major milestone and is also a prerequisite for optimal performance of activities of daily living (ADLs). Development of sitting posture control is a dynamic process involving control of degrees of freedom of head and trunk. Traditionally, trunk has been modeled as a single unit (segment). However, recent studies have suggested that it is made up multiple spinal units, controlled by a combination of trunk muscles. During typical development, posture control of trunk is different for different trunk segments. This motor development of trunk control is a complex process due to constant interaction between the nervous system …

Combating Malignant Melanoma With The Multifaceted Soy-Dervied Peptide Lunasin., Christopher Paul Shidal

Electronic Theses and Dissertations

Lunasin is a 44 amino acid peptide that has been shown to have cancer chemopreventative and chemotherapeutic properties. This study investigated the potential utility of Lunasin as a chemotherapeutic in melanomas. Studies showed that Lunasin had little activity against established melanoma cell lines using adherent culture methods; however, Lunasin’s in vitro activity was significantly higher in non-adherent colony-forming assays and oncosphere formation. These results led to the investigation of whether or not Lunasin has selective effects on cancer initiating cells (CIC) that are known to be present in melanomas. It was revealed that Lunasin selectively inhibited the proliferation of high-ALDH …

Spinal Cord Injury Induced Cardiac Decline And The Limitations Of Exercise., Kathryn Michele Deveau

Electronic Theses and Dissertations

There is a general consensus that the level and the severity of spinal cord injury (SCI) impacts chronic cardiac abnormalities such that high thoracic and cervical SCI are the most severely affected. Furthermore, the extreme degree of immobility/inactivity experienced by the persons with SCI has implications on cardiac decline. Yet it has been difficult to separate the relative contributions of the decentralized autonomic nervous system (ANS) and the immediate and profound inactivity to chronic cardiac abnormalities. As such, this body of work sought to characterize a contusion SCI that results in persistent CV dysfunction. Echocardiography, Dobutamine stress echocardiography and pressure …

Characterization Of A Mutant Oncolytic Adenovirus And The Role Of Jnk In Enhancing Virotherapy., Stephen L. Wechman

Electronic Theses and Dissertations

Oncolytic adenoviruses (Ads) have great therapeutic potential for lung cancer treatment. Cancer selective E1b-deleted Ads are safe; however, their clinical cancer therapeutic efficacy remains limited. The limited efficacy of Ad virotherapy is due to many factors including inefficient cancer cell lysis, Ad release and spread. Progress in overcoming these barriers to Ad virotherapy are hampered by limited knowledge of the genes associated with enhanced Ad release and spread and the dearth of understanding of the mechanisms by which E1b-deleted Ads cause cancer cell lysis. The role of c-JNK n- terminal kinase (JNK) phosphorylation in this process remains unknown. …

The Interaction Of Homoserine Lactones And Paraoxonase 2 Modulates Cell Death Signaling And Cell Proliferation., Aaron Mackallan Neely

Electronic Theses and Dissertations

Pseudomonas aeruginosa produces N-(3-oxododecanoyl)-homoserine lactone (C12) as a quorum-sensing molecule that functions to facilitate bacteria-bacteria communication. C12 has also been reported to affect many aspects of human host cell physiology, including evoking cell death in various types of cells. However, the signaling pathway(s) leading to C12-triggerred cell death remains unclear. To clarify cell death signaling induced by C12, we examined mouse embryonic fibroblasts (MEFs) deficient in one or more caspases. Our data indicate that, unlike most apoptotic inducers, C12 evokes a novel form of apoptosis in cells, probably through the direct induction of mitochondrial membrane permeabilization. Importantly, C12 induces apoptosis …

The Effects Of Moderate Alcohol Consumption And Inflammation On The Hepatic Matrisome And The Renal Cortex Proteome., Christine E. Dolin

Electronic Theses and Dissertations

Background. The association of chronic ethanol (EtOH) consumption with extracellular matrix (ECM) changes in alcoholic liver disease (ALD) is well established in the context of hepatic fibrosis. However, it is becoming increasingly understood that the hepatic ECM responds dynamically to stress well before fibrosis. The term “transitional tissue remodeling” describes qualitative and quantitative ECM changes in response to injury that do not alter the overall architecture of the organ; these ECM changes may contribute to early disease initiation and/or progression. The nature and magnitude of these changes to the ECM are currently poorly understood. In contrast to the liver, EtOH …

Targeting The Glucose Metabolism Of Myeloid-Derived Suppressor Cells (Mdscs) To Stimulate Cancer Immunity., Jaspreet Grewal

Electronic Theses and Dissertations

Myeloid derived suppressor cells (MDSCs) are a heterogeneous group of immature myeloid cells that are significantly increased in cancer patients and correlate with higher stage and poor prognosis. MDSCs negatively modulate anti-tumor immunity, suppress T cell activity, promote angiogenesis and increase the risk of metastasis. In this study, we report that monocytic-MDSCs (M-MDSCs) but polymorphonuclear-MDSCs (PMN-MDSCs) over-express 6-phosphofructo-2-kinase/fructose-2, 6-bisphosphatases 3 (PFKFB3), an important regulator of glycolysis. Furthermore in the melanoma model, M-MDSCs but not PMN-MDSCs suppressed T cell function which correlated with PFKFB3 over-expression and increased rate of glycolysis. PFKFB3 inhibition with the first-in-class small molecule inhibitor, PFK-158 reversed M-MDSC …

The Microbial Ecosystem Of Beer Spoilage And Souring: Competition And Cooperation In The Age Of Bioinformatics, Andrew Kettring

Electronic Theses and Dissertations

The brewing industry generates $350 billion in revenue in the US annually, representing 1.9% of the gross domestic product. Spoilage is a persistent problem throughout production and distribution that causes economic loss, and is therefore meticulously avoided. Contrarily, artisanal sour beers are necessarily produced by a diverse variety of these spoilage organisms metabolically interacting in symbiosis as a microbial ecosystem. We sought to gain insight into factors driving assembly of microbial communities by testing a long-debated Darwinian hypothesis. A collection of community members were screened in co-culture and novel bioinformatics tools were developed to predict observed interactions. A fundamental understanding …

Implication Of Alpha-Synuclein Transcriptional Regulation And Mutagenesis In The Pathogenesis Of Sporadic Parkinson's Disease, Sambuddha Basu

Electronic Theses and Dissertations

Parkinson's disease (PD) is an age-related neurodegenerative disorder characterized by selective loss of dopaminergic neurons (DA neurons) from the substantia nigra (SN) of the mid-brain. PD is classically associated with cytoplasmic inclusion of aggregated proteins called Lewy bodies. alpha-synuclein (α-SYN) coded by the gene SNCA, is one of the major components of Lewy body and neurite along with several other proteins like ubiquitin, neurofilament to name a few. PD is broadly categorized into two groups based on their incidence of occurrence. First is the familial form that occurs due to known genetic aberrations like mutation, gene duplication/triplication in important PD …

Targeted Therapy Development For Neurofibromatosis Type 2, Marisa Fuse

Electronic Theses and Dissertations

Neurofibromatosis type 2 (NF2) is a debilitating disease characterized by the formation of bilateral vestibular schwannomas, which compress the vestibulocochlear nerve and cause deafness. Additional peripheral schwannomas, meningiomas and ependymomas may also form. NF2 is caused by mutations in the NF2 gene, resulting in the loss of function of the merlin tumor suppressor. Merlin functions in multiple signaling pathways and its absence in Schwann cells yields increased cell survival and proliferation, thereby causing schwannoma formation. First line treatment for NF2 is watchful waiting and surgical removal of tumors, potentially resulting in facial paralysis and deafness. To date, there are no …

The Actin-Severing Protein Cofilin Is Downstream Of Neuregulin Signaling, Is Regulated By The Tumor Suppressor Merlin, And Is Essential For Schwann Cell Myelination, Nicklaus Sparrow

Electronic Theses and Dissertations

Myelination is a complex process requiring coordination of directional motility and an increase in Schwann cell (SC) size to generate a multi-lamellar myelin sheath. Regulation of actin dynamics during myelination is poorly understood. However, it is known that myelin thickness is related to the abundance of neuregulin1-type III (NRG) expressed on the axon surface. NRG binding to ErbB2/3 receptors on the Schwann cell surface initiates signaling cascades necessary for myelination. We identify cofilin1, an actin depolymerizing and severing protein, as a downstream target of NRG-ErbB2/3 signaling in rat SC. A five minute exposure of SCs to NRG triggers phosphorylation of …

Perceptual Variations In Thermoregulation During Exercise In A Hot Environment, William C. Alger

Electronic Theses and Dissertations

ABSTRACT

Professionals are seeking to find ways to prevent exertional heat illness (EHI) in populations working in hot environments as well as populations that are physically active. The purpose of the present study was to evaluate individuals’ ability to accurately perceive core temperature ranges associated with homeothermic and EHI temperatures during exercise. Ten physically active males exercised on a treadmill at a self-selected rate until core temperature reached 39°C. Participants rated perceived core and skin temperature on 100 mm scales each time core temperature increased 0.25˚ C (37.5-39.0˚ C), along with thermal comfort and sweating sensation. During exercise core temperature …

The Role Of The Mir-200 Family On The Tumor Suppressor Rassf2 And The Effect On Mapk Pathway Activity In Colorectal Cancer., Jane V. Carter

Electronic Theses and Dissertations

This dissertation investigated the role of the miR-200 family in normal colon epithelial (CCD 841) and Dukes’ C (HT-29) colorectal cancer (CRC) cell lines. Our aim was to characterize expression of the miR-200 family (miR-200a, miR-200b, miR-200c, miR-141, and miR-429) in colorectal cell lines, study their effect on the tumor suppressor Ras Associated Domain-Containing Protein (RASSF) 2 and on subsequent activity within the mitogen-activated protein kinase (MAPK) signaling pathway. We wanted to determine whether regulation of miR-200 family members could change cell behavior towards more “cancer-like” in a normal colon epithelium (CCD 841) cell line, or less “cancer-like” in a …

Evaluating Cardiovascular Dysfunction During Increased Activity And Exercise Rehabilitation Following Incomplete Thoracic Spinal Cord Injury In The Adult Rat., Kathryn A. Harman

Electronic Theses and Dissertations

Spinal cord injury (SCI) results in whole-body dysfunction. While the majority of SCI research is focused on improving locomotor function after injury, cardiovascular (CV) disease continues to be the leading cause of morbidity in the chronic SCI patient population. The combination of injury-induced destruction of autonomic pathways, maladaptive plasticity within lumbosacral circuits, and the progressive decline in physical fitness contribute to the poor CV status of SCI individuals. Currently, there is little emphasis on implementing appropriately-timed acute rehabilitation techniques aimed to curtail maladaptive remodeling and improve CV outcomes. Furthermore, no pre-clinical or clinical studies have investigated the most appropriate time-course …

Immune Monitoring In Recipients Of Combined Living Donor Kidney And Hematopoietic Stem/Facilitating Cell Transplants., Mark Dewayne Badder

Electronic Theses and Dissertations

Solid organ transplantation coupled with a hematopoietic stem cell transplant from the organ donor allows for the recipient to cease immunosuppressive therapy after transplant via a chimeric immune system. This beneficial effect of stem cell transplants is negatively affected by graft versus host disease (GVHD). Better understanding of the donor and recipient’s immune system is vital to mitigating graft versus host disease and induction of donor chimerism without GVHD. In this study, flow cytometry was used to characterize immune cells of the recipients’ before and up to eighteen months post transplantation. The recipients were categorized into their respective chimeric groups. …

The Role Of Nicotine, A7 Nicotinic Acetylcholine Receptors And Extracellular Matrix Remodeling In Pulmonary Fibrosis., Glenn Ward Vicary

Electronic Theses and Dissertations

The median survival for idiopathic pulmonary fibrosis (IPF) patients from diagnosis is a dismal 3 years. This condition is characterized by pulmonary fibroproliferation and excess production and disordered deposition of extracellular matrix (ECM) proteins resulting in obliteration of the original tissue architecture, loss of lung function and eventual death due to respiratory failure. The main hindrance to the development of effective treatments against pulmonary fibrosis is the late detection of its progression and is often of unknown cause. Tobacco smoke represents the most important environmental factor linked to the development of pulmonary fibrosis, with over 60% of IPF patients current …

The Effects Of Direct Peritoneal Resuscitation On Leukocyte Infiltration After Acute Brain Death., Jessica Lee Weaver

Electronic Theses and Dissertations

Background: Brain death triggers an inflammatory response that is associated with worse outcomes for recipients of transplanted organs procured from brain dead donors. The intestine has been shown to release inflammatory mediators in other types of shock, but its role is brain death is not well described. Direct peritoneal resuscitation (DPR) improves visceral organ blood flow and has been shown to reduce inflammation after hemorrhagic shock. Better understanding of this inflammatory process within the peripheral organs, the effects of DPR, and the role of the intestine could aid in better resuscitation of potential organ donors. Methods: Male Sprague-Dawley rats were …

The Role Of O-Glcnacase During Heart Failure., Sujith Dassanayaka

Electronic Theses and Dissertations

Global augmentation of protein O-GlcNAcylation occurs in response to a myriad of stressors and confers a survival advantage at the cellular level. This protective phenomenon has been demonstrated to mediate cardioprotection through various in vitro and in vivo studies during ischemia-reperfusion, myocardial infarction, and oxidative stress; however, relatively little is known of the regulation of protein O-GlcNAcylation. Protein O-GlcNAcylation is regulated by two antagonistic enzymes, namely, O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Ablation of cardiomyocyte OGT, the enzyme that catalyzes the addition of O-GlcNAc to proteins, exacerbates cardiac dysfunction during infarct-induced heart failure (HF). However, little is known of the …

Vinyl Chloride-Diet Interactions In Liver Disease : Potential Roles Of Autophagy And Energy Management., Anna L. Lang

Electronic Theses and Dissertations

Vinyl chloride (VC) is a prevalent environmental toxicant that has been shown to cause liver injury at high, occupational exposures. However, most studies have not addressed interactions of low doses with risk-modifying factors. This study aims to explore low-level VC metabolite exposure interactions with other potential risk-modifying factors and their effect on underlying liver disease. We examined sub-hepatotoxic effects of a VC metabolite (chloroethanol, CE) in two murine models of liver injury using ethanol and lipopolysaccharide (LPS). In both, CE significantly enhanced liver injury when compared to either ethanol or LPS alone. Previous studies have shown an increase in mTOR …

Toll-Like Receptor 4 Mutation Suppresses Hyperhomocysteinemia-Mediated Hypertension., Anastasia Familtseva

Electronic Theses and Dissertations

Background: Hyperhomocysteinemia (HHcy) has been observed to promote hypertension, but the mechanisms are unclear. Toll-like receptor 4 (TLR-4) is a cellular membrane protein that is ubiquitously expressed in all cell types of the vasculature. TLR-4 activation has been shown to promote inflammation that has been associated with pathogenesis of hypertension. In this study, we hypothesize that HHcy induces hypertension by TLR-4 activation that promotes inflammatory cytokine up-regulation (IL-1β, IL-6, TNF-α) and initiation of mitochondrial dysfunction leading to cell death and chronic vascular inflammation. Methods: To test this hypothesis, we used C57BL/6J mice (WT); Cystathionine-β-synthase deficient mice (CBS+/-) with genetic mild …