Medical Sciences Commons^™

Investigation Of Clinically Relevant Fluconazole Resistance Mechanisms In The Fungal Pathogen Candida Parapsilosis, Laura Anne Doorley

Theses and Dissertations (ETD)

Invasive candidiasis is a severe fungal infection associated with significant morbidity and mortality, particularly among the critically ill and immunocompromised. Candida parapsilosis is the most common non-albicans species causing invasive Candida infections in pediatric and neonatal populations worldwide and is particularly common in the countries of South America, Western Asia, Mediterranean Europe, and Southern Africa. For many of these countries, fluconazole and other triazoles are the first line antifungal agents used for effective treatment of invasive Candida infection. Until recently, rates of fluconazole resistance among C. parapsilosis isolates were relatively low, therefore the determination of clinically relevant resistance mechanisms in …

Vascular Mechanisms Of Rhabdomyolysis-Induced Acute Kidney Injury, Jeremiah Moyinolu Afolabi

Theses and Dissertations (ETD)

In patients with rhabdomyolysis, the overwhelming release of myoglobin into circulation is the primary cause of kidney injury. Myoglobin causes direct kidney injury as well as severe renal vasoconstriction. An increase in renal vascular resistance (RVR) results in renal blood flow (RBF) and glomerular filtration rate (GFR) reduction, tubular injury, and acute kidney injury (AKI). The mechanisms that underlie rhabdomyolysis-induced AKI are not fully understood but may involve the local production of vasoactive mediators in the kidney. Myoglobin stimulated endothelin-1 (ET-1) production in proximal tubular cells, an effect driven by NADPH oxidase-dependent oxyradical generation. Rats subjected to glycerol-induced rhabdomyolysis also …

Modulation Of Cerebral Artery Smooth Muscle Bk Channel Function By Neurosteroids, Kelsey Caroline Cleland North

Theses and Dissertations (ETD)

Voltage-gated and Ca2+ activated K+ channels of large conductance (BK) channels are essential for many key physiological processes, such as controlling the contraction of smooth muscle, including cerebrovascular smooth muscle. Importantly, BK channels are made up of a homotetramer of α subunits which associate with accessory β subunits. These β subunits alter the activity of the channel; this modulation is subunit-specific. Moreover, these accessory subunits have tissue-specific expression, such that the β1 subunit is highly expressed within cerebrovascular smooth muscle and greatly increases the open probability of BK channels. Increased BK channel open probability is linked to increased dilation of …

Transmission Competence Of B. Burgdorferi Infected Ixodes Ticks And Development Of An Ospc-Based Lyme Disease Vaccine, Samanta Kamalika

Theses and Dissertations (ETD)

Introduction. Lyme disease, otherwise called Lyme borreliosis, is a vector-borne infectious disease caused by the spirochete Borrelia burgdorferi (Bb). Studying the increase in overall Lyme disease incidence requires understanding the role of the vector Ixodes scapularis (I. scapularis) as the agent that carries the spirochete which is important to limit the occurrence of Lyme disease. Once we understand the vector-pathogen response, it also becomes important to determine the remedies for Lyme disease. Lyme disease can be treated with antibiotics if detected early, but the major obstacle lies in the early detection process. Therefore, it is important to investigate alternative preventive …

Physiologically-Based Pharmacokinetic (Pbpk) Modeling For The Preclinical Development Of Spectinamide Antibiotics, Keyur R. Parmar

Theses and Dissertations (ETD)

Despite being an ancient disease caused by Mycobacterium tuberculosis (Mtb) and after decades of research, tuberculosis (TB) still affects millions of people every year worldwide. In 2018, the World Health Organization (WHO) reported that 10 million people developed tuberculosis and 1.5 million died of the disease. With the increase in the multidrug-resistant (MDR) and extensively drug-resistant (XDR) cases, the treatment for TB with the standard first and second-line therapy is becoming increasingly difficult. Therefore, there is an urgent need to find new anti-TB drugs as combination partners of existing and experimental classes of antimicrobial agents to shorten and simplify the …

Exploring Risk Factors Of Alzheimer’S Disease Using Mouse Models, Xian Han

Theses and Dissertations (ETD)

Mouse models of Alzheimer’s disease (AD) that accurately recapitulate pathology and molecular changes are crucial for understanding disease mechanisms and subsequent therapeutic development. We examined five commonly used mouse models of AD (5xFAD, J20, APPNL-F, APPNL-G-F, Tau P301S) and compared their whole- and phosphoproteomes with human AD (the integration of three published datasets) to study whether they can mimic protein/RNA expression discrepancies, molecular changes, and enriched pathways found in human AD cases. The mouse models especially 5xFAD and APPNL-G-F show proteomic signatures similar to human AD but lack human-specific AD progressions, such as dysregulation of synaptic pathways and networks. Integration …

A Cloning-Free Recyclable System For Crispr-Cas9 Mediated Mutant And Reversion Construction In Candida Albicans Clinical Isolates, Amanda K. Vogel

Theses and Dissertations (ETD)

Candida albicans is a ubiquitous opportunistic fungal pathogen and one of the most prevalent causes of fungal diseases worldwide. The reference isolate SC5314 is one of the most widely used strains for both experimental and genetic studies, but it is becoming increasingly evident that genetic diversity in clinical isolates plays an important role in antifungal resistance, virulence, and pathogenicity. These recent discoveries highlight the need for genetic tools that are capable of investigating genes in multiple strain backgrounds. Here we build on the SAT1-flipper method and combine it with CRISPR-Cas9 technology to achieve cloning-free homozygous deletion in a single transformation …

Computer-Aided Drug Discovery For Helicobacter Pylori, Nicole Ann Vita

Theses and Dissertations (ETD)

Helicobacter pylori is a high-priority drug-resistant pathogen and is currently the only bacteria considered to be a class I carcinogen and there is a critical need to identify novel chemical matter to treat H. pylori infections. Hp is responsible for greater than 60% of gastric cancer related deaths and 89% of all gastric cancer morbidities. In a previous study, our lab identified novel Hp thienopyrmidine inhibitors that target respiratory complex I, an essential enzyme in respiration. Respiratory complex I is a large asymmetric multidomain and membrane bound enzyme and due to these innate features, it is not practical for biophysical …

Methods Development In Inflammatory Bowel Disease, Andrew B. Steimke

Theses and Dissertations (ETD)

Inflammatory bowel disease (IBD) is a disease that is classified into two subtypes: ulcerative colitis (UC) and Crohn’s disease (CD). Symptoms can range from mild discomfort to requiring surgical intervention and affects approximately 1-in-200 adults in America alone, with global incidence rates increasing. While many treatments exist for IBD, perhaps the main reason for the lack of a cure is that there are many different pathogeneses that all lead to a very similar expression of symptoms. Over 240 IBD loci have been identified to date, yet the causative allele that drives the association has only been identified in ~60 of …

Olfactory Processing In The Piriform Cortex Of Awake, Freely Moving Mice, Ian F. Chapman

Theses and Dissertations (ETD)

The piriform cortex (PC) has long been established as the primary cortical recipient of olfactory information in the mammalian brain. In rodents, information extracted from recordings of PC neurons can accurately decode the identity of odors, leading to delineation of PC as the primary cortical region involved in the formation of odor perception. Unfortunately, due to technical limitations, many of the prior studies establishing these coding principles were performed without the ability to track the responses of the same cells over time. Additionally, recordings have often relied on head-fixation to minimize diffusion of odor stimuli, limiting movement range and natural …

Cerebellar Coordination Of Neuronal And Behavioral Rhythms, Brittany Correia Chapman

Theses and Dissertations (ETD)

Long known for its role in motor control, it is increasingly clear that the cerebellum is also involved in numerous cognitive and affective behaviors. Though the neuronal mechanism for the role of the cerebellum in cognition is still unclear, there is a consensus that it involves cerebellar interactions with the cerebral cortex. Recent studies suggest that the cerebellum monitors, and possibly coordinates, the precise phase alignment or coherence of neuronal oscillations in cerebral cortical areas. Here, we asked how loss of cerebellar function affects respiratory rhythms and the interactions of local field potential (LFP) oscillations between the lobulus simplex (LS) …

Inflammatory Response Following Hemorrhagic Stroke: The Role Of Cytokines, Patrick Devlin

Theses and Dissertations (ETD)

Hemorrhagic stroke is a dangerous form of stroke resulting from the rupturing of weakened blood vessels, releasing blood that increases intracranial pressure and causes the death of surrounding tissue. Treatment options are improving but remain limited, as evidenced by this condition being characterized by high rates of mortality as well as long-term morbidity. Unregulated inflammatory responses that occur following injury may be partially to blame for these poor outcomes. In response to any injury, the immune system releases cytokines to recruit immune cell activation and promote inflammation. But after hemorrhagic stroke, whether aneurysmal subarachnoid hemorrhage (aSAH) or intracerebral hemorrhage (ICH), …

Host-Pathogen Interactions During Leptospirosis In Male C3h/Hej Mice, Advait Bhaskar Shetty

Theses and Dissertations (ETD)

Leptospirosis is a zoonotic disease transmitted from reservoir hosts like rodents to other animals and humans, who are incidental hosts. This infection is prevalent in the areas of Southeast Asia, Africa and South America. Inactivated Leptospira serovars vaccines are available in endemic areas but they have certain limitations such as serovar specificity and short-term protection. Antibiotics are effective treatment strategies useful at least during early stages of infection. Early diagnosis of Leptospirosis is difficult due to lack of accessible laboratory and point of care tests and due to clinical similarities with other diseases. Thus, it is important to understand host-Leptospira …

Identification Of Therapeutic Targets For Th17 Cell-Mediated Diseases, Jin Wang

Theses and Dissertations (ETD)

Hypersensitivity and autoimmune diseases are complex synergistic effect of environmental, genetic and other factors. T helper 17 (Th17) cells play a critical role in the immune pathology. Th17 cells are a group of specialized CD4+ T cells with potential pro-inflammatory function which are different from other T cells such as T helper 1 (Th1) cells or T helper 2 (Th2) cells. Th17 cell development and differentiation processes are strictly regulated through complex pathways. Th17 cells are characterized by secreting cytokines such as IL-17 and IL-22. Studies have shown that Th17 cells and IL-17 have been implicated in the pathogenesis of …

Targeting Myeloid Protein Kinase C Signaling To Overcome Immune Suppression And Improve Immunotherapy In Cancer, Mehdi Chaib

Theses and Dissertations (ETD)

Checkpoint immunotherapy unleashes T cell antitumor potential which has revolutionized cancer treatment showing unprecedented long-term responses. However, most patients do not respond to immunotherapy which often correlates with a dysfunctional or immunosuppressive myeloid compartment. Immunosuppressive myeloid cells comprise Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) and can suppress T cells via production of immunosuppressive factors. Conversely, efficient cytotoxic T cell priming is dependent on the ability of antigen-presenting cells (APCs), mainly conventional dendritic cells (cDCs) and macrophages, to present or cross-present tumor antigens to T cells. Thus, targeting immunosuppressive myeloid cells while simultaneously enhancing APCs represents a promising strategy …

The Role And Immunogenicity Of Cbfa2t3-Glis2 In Pediatric Acute Megakaryoblastic Leukemia, Elizabeth A. Garfinkle

Theses and Dissertations (ETD)

CBFA2T3-GLIS2 is the most prevalent fusion oncogene in pediatric acute megakaryoblastic leukemia in patients without Down syndrome (non-DS-AMKL) and is associated with an event free survival of only 8% even with high intensity chemotherapy and stem cell transplant in first remission. A cryptic inversion event on chromosome 16 joins the three nervy homology regions (NHR) of CBFA2T3 to the five zinc fingers of GLIS2. This configuration enables the encoded chimeric transcription factor to bind GLIS consensus sequences throughout the genome and recruit transcriptional activators and repressors to alter gene expression and enhance self-renewal capability. Few cooperating mutations have been identified …

A Neurophysiological Investigation Of Listening Effort In Normal Hearing Adults Using Fnirs And Pupillometry, Jessica Defenderfer

Theses and Dissertations (ETD)

Real-world conversations are often accompanied by some sort of interference that challenges the clarity of the speaker’s message, causing listeners to exert more effort to understand speech. Previous research has demonstrated that when listening to speech becomes difficult, various regions of the brain are recruited beyond those which engage during optimal listening conditions. However, the neural correlates that underly listening effort are not fully understood. Importantly, the pupillary response can be used to index listening effort, such that pupil size increases with increasing cognitive demand. I proposed that pupillometry can be used to characterize the cortical response, such that changes …

Cellular Dynamics And Disease Outcome Of Type 3 Streptococcus Pneumoniae Clinical Isolates Differ Between Strains, Taylor Rae Plunkett White

Theses and Dissertations (ETD)

Streptococcus pneumoniae is a bacterial pathogen that continues to be a major cause of disease around the world. It is not only the number one cause of bacterial pneumonia but also the cause of about 15% of the deaths of children under 5 around the world. There is a lot of research done on this organism, but with around 100 known serotypes and each one producing a unique capsule, there is still much more to be studied. The Etiology of Pneumonia in the Community (EPIC) study conducted by the CDC observed the burden of hospitalizations caused by pneumonia while determining …

A Rodent Animal Model For Forelimb To Lower Jaw Reorganization In Primary Somatosensory Cortex (Si) Barrel Field, Violeta Pellicer Morata

Theses and Dissertations (ETD)

The goal of this study is to examine mechanisms underlying cortical reorganization in rat primary somatosensory (SI) cortex that follows forelimb deafferentation. The majority of human patients suffering from limb loss or brachial plexus avulsion injury, as well as patients that receive brachial plexus anesthesia, report phantom limb sensations/pain which are often associated with cortical reorganization. Patients with upper-limb deafferentation report sensations of the missing hand during tactile stimulation of the face, and this phenomenon has been termed hand-to-face remapping. We sought to develop a rodent model of deafferentation; our model system is the rat SI cortex barrel field present …

Mitophagy-Mediated Regulation Of Ros Homeostasis During Hsc Activation Contributes To Cell Fate, Amber Lynne Smith

Theses and Dissertations (ETD)

The ability of hematopoietic stem cells to self-renew and differentiate is required for the maintenance of all blood lineages under basal physiologic conditions and in response to inflammatory stress. The degradative capacity of the autophagy-lysosomal system is a determinant of hematopoietic stem cell (HSC) activation status with low autophagy predicting activation of HSCs, and autophagy deficiency causing the spontaneous loss of quiescence and HSC exhaustion. Although an increase in mitochondrial activity has been suggested as the cause of HSC depletion in autophagy-defective models, the contribution of mitophagy to HSC function remains to be elucidated. Here, we capitalized on the observation …

Developing Targeted Therapies For T-Cell Acute Lymphoblastic Leukemia, Jianzhong Hu

Theses and Dissertations (ETD)

Introduction Acute lymphoblastic leukemia (ALL) is the most common cancer in children, and risk-adapted chemotherapies have dramatically improved the outcomes of this disease. Compared to B-cell ALL, T-cell ALL (T-ALL) is more aggressive and has worse outcomes from chemotherapy. There is a great unmet need to develop biomarkers and novel targeted therapies for this type of cancer. Working together with internal and external collaborators, we performed a large-scale pharmacotyping assay in over 300 primary ALL samples. By combining pharmacotypying and genomic profiling of these samples, we identified a substantial T-ALL population that showed strong response to dasatinib, a known ABL1 …

Immunomodulatory Roles Of The Lysosomal Sialidase Neuraminidase 1, Leigh Ellen Fremuth

Theses and Dissertations (ETD)

Background Sialic acids are key sugar moieties located at the non-reducing terminals of glycan chains on glycoproteins and glycolipids. By virtue of their location, they influence the functions and biochemical properties of the macromolecules they are bound to. Removal of sialic acids in mammalian cells is carried out by four sialidases, which are differentially expressed and localized in distinct subcellular compartments. Neuraminidase 1 (NEU1), the most abundant and ubiquitous of the four sialidases, functions primarily in the acidic environment of the lysosomes, but can hydrolyze substrates at the plasma membrane, at least in certain cell types. The enzyme initiates the …

Using Crispr Gene Editing To Prevent Accumulation Of Lipids In Hepatocytes, Erin Young, Cem Kuscu, Christine Watkins, Murat Dogan

Longitudinal Scholar's Project

CRISPR gene editing is a molecular technology that can be used to silence gene expression. In this experiment, genes that are known to play a role in lipid accumulation in hepatocytes were targeted. Specifically, levels of fatty acid transport proteins 2 and 5 (FATP2 & 5) have been shown to be elevated in cases of non-alcoholic fatty liver disease. The goal of this experiment was to reduce expression of these genes by using a dead Cas9 (dCas9) protein with an attached inhibitory domain (KRAB) that acts on the promotor region. When measuring the mRNA expression, it was determined that the …

Ecology Of Hantaviruses In Rodent Reservoirs And Their Early Innate Immune Responses In Human Model Systems, Evan Peter Williams

Theses and Dissertations (ETD)

The spillover of zoonotic RNA viruses is responsible for a great deal of the disease outbreaks in human populations. These spillover events are set to continue due to anthropogenic and environmental changes that impact the distribution of these viruses. The viruses in the family Hantaviridae are classified as one of these emerging zoonotic RNA viruses. The spillover of the viruses in this family are responsible for two severe human diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). These viruses are distributed across the globe and are responsible for a large number of human disease cases with …

Environmental And Genetic Factors Affecting Bone Diseases And Phenotypes In Mouse Models, Wei Dong

Theses and Dissertations (ETD)

Bone diseases and phenotypes are affected in multiple ways. We focused on studying the effects of genetic and environmental factors, especially their impact on bone properties. Firstly, we investigated the effects of β-caryophyllene (BCP), a naturally occurring dietary cannabinoid, on protecting bone from vitamin D deficiency in mice fed on a diet lacking or supplemented with vitamin D (VD). We found that the VD-deficient diet enhanced the length of femur and tibia bones (P<0.05), and increased bone volume (BV; P<0.01) and the trabecular bone volume fraction (BV/TV; P <0.01) compared to the D+ diet. When given BCP-containing diet, mice exhibited higher BV and bone mineral density (BMD; P<0.05) than the control group. The trabecular and cortical bone were also affected by VD and BCP. In addition, the inclusion of dietary BCP improved the serum concentrations of klotho (P < 0.05). In summary, these data indicate that BCP enhances the level of klotho in the serum, leading to improved bone properties and mineralization in an experimental mouse model. Under conditions lacking UV light, the D-deficient diet could affect multiple properties of bone, including trabecular and cortical bone, in mice. The D-deficient diet can also result in weight loss in mice.

My second project is to evaluate the bone properties in a mouse model with Il-1rn mutation. When knockout for IL-1rn, mice of Balb/c genomic background exhibited …

Identifying The Molecular Cause Of Extreme Endoplasmic Reticulum Dilation In Pediatric Osteosarcoma And Its Relationship To The Disease, Rachael Wood

Theses and Dissertations (ETD)

Pediatric osteosarcoma tumors are characterized by an unusual abundance of grossly dilated endoplasmic reticulum and an immense genomic instability that has complicated identifying new effective molecular therapeutic targets. Here we report a novel molecular signature that encompasses the majority of 108 patient tumor samples, PDXs and osteosarcoma cell lines. These tumors exhibit reduced expression of four critical COPII vesicle proteins that has resulted in the accumulation of procollagen-I protein within ‘hallmark’ dilated ER. Using CRISPR activation technology, increased expression of only SAR1A and SEC24D to physiologically normal levels was sufficient to restore both collagen-I secretion and resolve dilated ER morphology …

Characterizing And Overcoming Resistance To Aminomethylspectinomycins In Gram-Negative Bacteria, Nisha Das

Theses and Dissertations (ETD)

Spectinomycin (SPC) is a broad-spectrum aminocyclitol antibiotic. Its use in agriculture has led to widespread resistance in enteric bacteria, necessitating the development of more effective analogs. Aminomethyl spectinomycins (amSPC) are modified spectinomycins with increased potency against many bacterial species. These species include Legionella pneumophila, which harbors a chromosomally encoded aminoglycoside modifying enzyme (AME). In this study, we follow up on this observation and examine the extent to which the amSPCs are substrates for AMEs through adenylation (ANTs) and phosphorylation (APH). APH(9)-Ia and ANT(3")(9) were expressed in E. coli BL21(DE3) and purified using the Ni-affinity chromatography. The ability of AMEs to …

The Effect Of Cancer Cachexia Progression On The Feeding Regulation Of Skeletal Muscle Protein Turnover, Brittany R. Franch

Theses and Dissertations (ETD)

Cancer cachexia is defined as the unintentional loss of skeletal muscle mass with or without fat loss that cannot be reversed by conventional nutritional support. Cachexia occurs in ~20% of cancer patients. More specifically, 50% of lung cancer patients, the most common cancer worldwide, develop cachexia. Cachexia occurs most often in lung and gastrointestinal cancers, whereas breast and prostate have the lowest rate of cachexia. Cancer-induced cachexia disrupts skeletal muscle protein turnover (decreasing protein synthesis and increasing protein degradation). Skeletal muscle’s capacity for protein synthesis is highly sensitive to local and systemic stimuli that are controlled by mTORC1 and AMPK …

Impact Of Central Line Bundle Care On Reduction Of Central Line Associated-Infections: A Scoping Review, Alisha James-Scott Msn, Fnp-C, Rachel Savoy Msn, Fnp-Bc, Donna Lynch-Smith Dnp, Acnp-Bc, Apn, Ne-Bc, Cnl, Tracy Mcclinton Dnp, Ag-Acnp-Bc, Apn

Doctor of Nursing Practice Projects

Purpose/Background Central venous catheters (CVC) are typical for critically ill patients in the intensive care unit (ICU). Due to the invasiveness of this procedure, there is a high risk for central line-associated bloodstream infection (CLABSI). These infections have been known to increase mortality and morbidity, medical costs, and reduce hospital reimbursements. Evidenced-based interventions were grouped to assemble a central line bundle to decrease the number of CLABSIs and improve patient outcomes. This scoping review will evaluate the literature and examine the association between reduced CLABSI rates and central line bundle care implementation or current use.

Methods A literature review was …

The Molecular Mechanisms Of Estrogen Receptor Α On Two Single Nucleotide Polymorphisms To Regulate Wnt Signaling In Osteoblasts, Sarocha Suthon

Theses and Dissertations (ETD)

Osteoporosis is the most common bone metabolic disorder, affecting over 200 million people globally. It is characterized by bone mass depletion and microarchitectural deterioration, leading to bone fragility and susceptibility to bone fracture. Genetic factors, estrogen deficiency, and dysregulation of the WNT signaling pathway contribute to the development of this disease. Genome-wide association studies have predicted that the single nucleotide polymorphisms (SNPs) rs2887571 and rs9921222 associate with low bone mass, but the mechanism of these SNPs has remained unknown. Analysis of osteoblasts from 112 different joint replacement patients reveals that the genotype of rs2887571 correlates with WNT5B expression, and the …