Medicine and Health Sciences Commons^™

Development, Validation, And Diagnostic Performance Of A Novel Radiomic Model For Predicting Prostate Cancer Recurrence, Linda M. Huynh

Theses & Dissertations

Multi-parametric magnetic resonance imaging (MP-MRI)-derived radiomics have been shown to capture sub-visual patterns for the quantitative characterization of prostate cancer (PC) phenotypes. The present dissertation seeks to develop, evaluate, and compare the performance of an MRI-derived radiomic model for the prediction of PC recurrence following definitive treatment with radical prostatectomy (RP).

MP-MRI was obtained from 339 patients who had a minimum of 2 years follow-up following RP at three institutions. The prostate was manually delineated as the region of interest and 924 radiomic features were extracted. All features were evaluated for stability via intraclass correlation coefficient (ICC) and image normalization …

Central Activation Of Orl-1 Receptors In Heart Failure Models, Jeffrey Angell

Theses & Dissertations

Heart failure is a prevalent and debilitating disease associated with high morbidity and mortality rates worldwide and is the leading cause of death in the United States. While various therapeutic strategies have been developed and approved to manage heart failure, exploration of novel targets and mechanisms are essential for improving patient outcomes. This thesis investigates the therapeutic potential of the central activation of opioid receptor-like 1 (ORL-1) by nociceptin in a rodent heart failure model.

Furthermore, this study aims to elucidate the central mechanisms underlying nociceptin induced cardiovascular and renal effects in heart failure. This involves investigating neuronal pathways and …

Effect Of Computerized Cognitive Training In Persons With Multiple Sclerosis, Sam Jack

Theses & Dissertations

Between one million and 1.75 million persons with multiple sclerosis (PwMS) worldwide are estimated to suffer from cognitive impairment. Unfortunately, there is currently no consensus on the best treatment for cognitive impairment in PwMS. Finding non-pharmacological interventions to mitigate cognitive decline is essential to ensure that quality of life for PwMS matches our ability to treat and mitigate their physical symptoms of MS. Computerized cognitive training has emerged as a potential option for PwMS suffering from cognitive impairment. The objective of this study was to determine the effectiveness of computerized cognitive training with BrainHQ on changes in cognitive impairment for …

Evaluating The Impact Of Routine Enteral Iron Fortification On Gastrointestinal Dysbiosis In Premature Infants, Matthew Van Ormer

Theses & Dissertations

The gastrointestinal microbiome in preterm infants bears significant influence on optimal outcomes – dysbiosis is shown to substantially increase the risk of the life-threatening necrotizing enterocolitis, whereas optimal microbiome composition improves nutrient digestion and immune function. Iron is a vital nutrient especially during the perinatal window of rapid hemoglobin production, tissue growth, and foundational neurological development. However, excess colonic iron exhibits potent oxidation capacity and alters the competitive environment of microbes – potentially facilitating the proliferation of pathological bacterial strains in the gut. Of note, breastfed preterm infants routinely receive iron fortification starting at 14 days of life and are …

Cystic Duct Morphology And Heister Valves: A Cadaveric Study, Cierra R. Goerish

Theses & Dissertations

Continued occurrence of cholelithiasis, gallstones, commonly results in cholecystectomy, removal of the gallbladder. Having a comprehensive anatomical, histological, and physiological knowledge of the biliary apparatus is imperative in clinical medicine today. Additionally, the functionality of cystic duct (CD) Heister valves (HV) has been speculatory since being reported in 1732. This study summarizes the morphology, orientation, and variability of the gross biliary system and provides data to help justify HV functionality.

Cadaveric dissection was utilized for gross observation and analysis of the biliary system. The angulation of the CD was found primarily as an acute angle; however, obtuse angulation could be …

Transcranial Direct Current Stimulation Of Frontal/Occipital Cortices Modulates Neural Correlates Of Cognition In Healthy Young Adults, Yasra Arif

Theses & Dissertations

An exponential rise in the use of transcranial direct current stimulation (tDCS) to modify the human brain and behavior has been observed over the last 20 years, with studies often yielding mixed outcomes. Such heterogeneity is partially attributed to the lack of a concise understanding of the underlying mechanisms. Though considered to exert modulatory effects by changing neuronal membrane polarization and synaptic efficacy, the interactive effects of offline tDCS and the neural underpinnings of cognition, both at the regional and network-level, are yet to be fully understood. Using High-Definition tDCS (HD-tDCS), Magnetoencephalography (MEG), a range of well-established cognitive paradigms, and …

Diagnostic Accuracy Of High-Sensitivity Cardiac Troponin In The Diagnosis Of Acute Myocardial Infarction At The Aga Khan University Hospital Nairobi, Kenya, Assumpta Wanjiru Chege

Theses & Dissertations

Methodology: This cross-sectional study was carried out at Aga Khan University Hospital, Nairobi between July 1st 2020 and December 31st 2021. Participants were adults aged 18 years and above presenting to the emergency department with signs and symptoms suggesting an acute myocardial infarction. Patients were identified on the hospital management information system (CARE 2000) using test results for baseline high-sensitivity cardiac troponin I. The final diagnosis as well as secondary clinical data was obtained from both physical and electronic patient medical records. The reference standard for the diagnosis of acute myocardial infarction was taken as the final clinical diagnosis made …

Optimizing Antiretroviral Therapy With Modern Rifapentine Containing Tb Treatment, Anthony T. Podany

Theses & Dissertations

In the past decade there has been a multitude of phase 3 clinical trials targeting treatment shortening for tuberculosis (TB). The synthetic rifamycin derivative rifapentine (RPT) has been at the forefront of many of the treatment shortening approaches. RPT possesses greater potency and a longer pharmacokinetic (PK) half-life (t_1/2) as compared with the long used rifamycin, rifampin (RIF). For TB preventative treatment, a 3-month, once weekly regimen of RPT and isoniazid (INH; 3HP) was shown to be as effective as 9-months of daily INH therapy in the PREVENT TB trial. Similarly, a 4-week course of daily RPT and …

The Role Of Calprotectin In T-Lymphocyte Driven Inflammation In A Mouse Model Of Psychological Trauma, Cassandra Moshfegh

Theses & Dissertations

Post-traumatic stress disorder (PTSD) is a debilitating psychological disorder that affects nearly 45 million Americans. This mental disorder is characterized by behavioral symptoms such as learned helplessness, hyperarousal, withdrawal, and flashbacks. The deleterious effects of PTSD are far-reaching and go beyond behavioral dysfunction, as these individuals are at a three-fold higher risk of comorbid inflammatory diseases. Autonomic, metabolic, and cardiovascular diseases plague these individuals later in their lifetime, however, the mechanistic link connecting psychological trauma to this systemic peripheral immunological dysfunction remains elusive. T-lymphocyte-induced inflammation plays a significant role in all these disease pathologies. Previous work from our laboratory demonstrated …

Tourniquet-Induced Ischemia-Reperfusion Injury, Junliang Qian

Theses & Dissertations

Ischemia-reperfusion (IR) is a pathological condition characterized by an initial restriction of blood supply to an organ followed by subsequent restoration of reperfusion associated with exacerbation of tissue damage. For pre-hospital emergency situations and surgical procedures, tourniquet or femoral artery ligation are widely used to stop extremity hemorrhage or create a bloodless operating field. To fully evaluate the underlying mechanisms in IR pathophysiology and potential therapeutic options, we compared tourniquet- and femoral artery ligation-induced IR injuries in the hindlimb of mice. We found that tourniquet/IR-induced acute hindlimb injuries are more severe than those induced by femoral artery ligation/IR, including alteration …

Gut Commensals Modulate Siv/Shiv Pathogenesis And Therapeutics, Samuel Johnson

Theses & Dissertations

Despite significant advancements in combination antiretroviral therapy (cART), ongoing inflammation in the brain and gut remain two of the most significant hurdles in the health of people living with human immunodeficiency virus (HIV). Additionally, a viral reservoir in each compartment inhibits cure efforts by allowing rapid viral rebound following cART interruption. Emerging understanding of the gut-brain axis (GBA) implicates each compartment in the modulation of the other in a complex bi-directional interaction mediated by vagus innervation, circulating lymphocytes, and microbiome composition and biproducts. Using multiple models of the simian (and simian-human) immunodeficiency virus (SIV/SHIV) and therapeutic intervention, I present how …

Modulating Cardiac Remodeling After Myocardial Infarction, Upendra Chalise

Theses & Dissertations

Cardiac remodeling after myocardial infarction (MI) is indicated by infarct wall thinning, reduced ejection fraction, and dilation of the left ventricle (LV). Inflammation presides in the early days of MI as a key event in cardiac wound healing. Infiltration of inflammatory cells, predominantly neutrophils and macrophages, is stimulated by ischemic cardiomyocytes that secrete inflammatory cues. This dissertation focused on identifying factors that influence cardiac remodeling after MI. S100A9 is a neutrophil-derived factor identified that exacerbated infarct wall thinning and cardiac dilation by increasing neutrophil and macrophage infiltration. Similarly, murinoglobulin 1 (Mug1) and galectin (Lgals)3 were macrophage-derived factors identified that regulate …

Erα As A Modulator Of The Sle1b Lupus Susceptibility Locus And B Cell Receptor Signaling, Jared H. Graham

Theses & Dissertations

Systemic Lupus Erythematosus (SLE) is an autoimmune disease characterized by loss of immune tolerance and the production of anti-nuclear autoantibodies. 90% of lupus patients are women, and this sex bias is due to the actions of estrogens, which promote lupus pathogenesis. Our lab has shown that estrogen receptor alpha (ERα) mediates the effect of estrogens in lupus and that ERa acts in a B cell intrinsic manner to promote the development of autoantibodies and SLE. Genetic factors also contribute to lupus. One major lupus susceptibility locus, Sle1, controls loss of tolerance and autoantibody development as well as immune cell …

Psychological Trauma Alters T-Lymphocyte Inflammation And Redox Through Sympathetic Mechanisms, Safwan K. Elkhatib

Theses & Dissertations

Posttraumatic stress disorder (PTSD) is a devastating psychiatric disorder characterized by distinctive symptom clusters, including intrusive memories (i.e., flashbacks), avoidance of related stimuli, affective changes, and hyperarousal. Strikingly, patients with PTSD face a significantly increased risk for a number of inflammation-driven pathologies, ranging from cardiovascular to autoimmune disease. Yet, the exact etiology of this increased risk remains unknown. The immune system is known to be strongly influenced by the sympathetic nervous system, and sympathetic overactivity is a hallmark of PTSD. Lymphoid organs, such as the spleen, are richly innervated by sympathetic nerve fibers which terminate near adaptive immune …

Engineering Advanced Micro And Nanofiber Materials For Biomedical Applications, Alec D. Mccarthy

Theses & Dissertations

At the functional crossroads of engineering and biomedical sciences lies the interdisciplinary field of biomedical engineering. Principles of biomedical engineering are vast, and the rigorous application of engineering towards clinically-relevant medicine has the ability to take novel concepts from bench to bedside. Arguably one of the most promising and productive sub-fields within the biomedical engineering discipline is biomaterial engineering. Here, novel biomaterials, synthesized from natural, synthetic, or hybrid materials, can be used in tissue repair and regeneration, hemostasis, as anatomical support and drug delivery vessels, or as diagnostic devices.

Of particular interest are applications of nanofiber and microfiber objects, which …

Evaluation Of Stratified Antibiograms For Use In Laboratory And Antimicrobial Stewardship, Linsey Donner

Theses & Dissertations

Antibiograms are critical for choosing empiric antimicrobial therapy. Cumulative antibiograms, which aggregate susceptibility data, can mask differences within specific patient subsets or clinical syndromes. This dissertation was done to determine if antibiotic susceptibilities showed substantial differences when comparing stratified antibiograms to cumulative antibiograms.

Antibiotic susceptibility data was retrospectively obtained from Nebraska Medicine January 1, 2017 – December 31, 2019 for Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecalis. The University of Nebraska Medical Center’s web antibiogram clinical decision support tool was used to export the data. Bacteria-antibiotic susceptibility rates of stratified antibiograms …

Urinary Bile Acid Indices As Prognostic Biomarkers For The Complications Of Liver Diseases, Wenkuan Li

Theses & Dissertations

Hepatobilary diseases cause the accumulation of toxic bile acids (BA) in the liver, blood, and other tissues, which may lead to an unfavorable prognosis. In this study, we compared the urinary BA profile in 257 patients with hepatobilary diseases during a 7-year follow-up period. We investigated the use of the urinary BA profile to develop logistic regression models to predict the prognosis of hepatobiliary diseases in terms of developing disease-related complications, especially for ascites. The urinary BA profile was characterized by calculating BA indices, which quantify the composition, metabolism, hydrophilicity, and toxicity of the BA profile. All patients had high …

Use Of Telehealth In Home-Based End-Of-Life Care For Children In Rural Regions, Meaghann S. Weaver

Theses & Dissertations

A national shortage in pediatric-trained providers results in certain geographies, primarily rural, where children with special needs are not able to access home-based care at their end-of-life. Advances in technology have made the use of telemedicine a potential modality for palliative care subspecialty clinicians to provide clinical care and support for adult-trained hospice teams. This dissertation utilizes four approaches to consider telehealth as an unexplored opportunity in care delivery: (1) a systematic review of telehealth measures and instruments to select the Technology Acceptance Model as a validated metric of telehealth acceptance uniquely now applied to pediatric care; (b) a pilot …

Gene Expression Profiling Of Mapk Pathway Inhibitor Resistance In Cutaneous Melanoma: Can Bioinformatics Be Used To Select Better Melanoma Cell Lines?, Stephen Luebker

Theses & Dissertations

Melanoma is the deadliest form of skin cancer, and incidence has continued to increase. Half of all melanomas have a BRAF V600E mutation and respond to MAPK pathway inhibitors, including BRAF inhibitor therapy or BRAF/MEK inhibitor combination therapy, but nearly all patients develop treatment resistance. Melanoma cell lines produce variable results as models of MAPK pathway inhibitor resistance. To better understand how the genomic similarity of a melanoma cell line to patient-derived tumors affects resistance mechanisms, differences in DNA mutations and copy-number alterations were compared between melanoma cell lines profiled by the Cancer Cell Line Encyclopedia and cutaneous melanoma tumors …

Proof Of Concept: The Use Of Renal Biomarkers In Critically Ill Pediatric Patients For Therapeutic Drug Monitoring, Christopher Lee Shaffer

Theses & Dissertations

Acute kidney injury (AKI) is a serious and common complication in critically ill pediatric patients. The incidence of pediatric AKI continues to increase, especially in patients who undergo surgical correction of congenital heart defects. Serum creatinine and urine output are the most commonly used tools to assess renal function, with international guidelines standardizing AKI-definitions based upon these parameters. However, changes in serum creatinine can occur 24 hours or later after a renal insult event, delaying the diagnosis and potential interventions to reverse injury. It is critical to identify endogenous renal biomarkers within the pediatric population that are both timely and …

Molecular Pathogenesis Of A Novel Subgroup Of Peripheral T-Cell Lymphomas, Jiayu Yu

Theses & Dissertations

Peripheral T-cell Lymphoma (PTCL) consists of numerous distinct disease entities. With the current diagnostic criteria over a third of the cases cannot be further classified and are called "not otherwise specified" (PTCL-NOS). Using gene expression profiling (GEP) of tumors, we identified two novels PTCL-NOS molecular subgroups either characterized by high expression of GATA3 (33%), which is associated with Th2 cell differentiation, or high expression of TBX21 (49%) which regulates Th1 cell maturation. Therefore, stratifying patients for diagnosis and identifying the underlying genetic basis to improve clinical therapy becomes critical to prognosis.

First, we performed DNA copy number analysis by using …

The Utility Of An Initial Point-Of-Care Lactate In Predicting In-Hospital Mortality Among Adult Patients With Sepsis And Septic Shock At The Emergency Department Of A Tertiary Hospital In Nairobi, Gicheru B. Nyachira

Theses & Dissertations

Background: Sepsis is a leading cause of death and now a global health priority. Rapid identification, diagnosis and intervention can result in reduced in-hospital mortality. Elevated lactate has been shown to be a strong predictor of in-hospital mortality. However, the optimal cut-off has not been well defined. Identification of the optimal Point-of-Care (POC) lactate cut off that best predicts in-hospital mortality can therefore be used to rapidly risk stratify patients with suspected sepsis and septic shock presenting to the emergency department allowing for immediate intervention.

Objective: To determine the lactate cutoff from an initial Point-of-Care lactate result from a GEM …

An Explanatory Sequential Mixed Methods Nutrition And Physical Activity Intervention Study On Changes In Knowledge, Self-Efficacy, And Outcome Expectations Of Fathers, Sarah Hortman

Theses & Dissertations

Overweight and obesity rates are a continuing concern resulting in poor health outcomes and annual healthcare costs in the billions of dollars. An upstream approach of health promotion is critical to change the focus from treatment and management to prevention of chronic disease. Preventing chronic disease through evidence-based health promotion practices incorporating educational interventions aimed at dietary and physical activity behaviors will preclude negative health outcomes including cardiovascular disease, type 2 diabetes, and hypertension.

The family environment is an important consideration in the prevention of chronic disease including obesity. Parents are role models for their children, including fathers who are …

Clinical Consequences And Determinants Of False Positive Blood Cultures In Adult Hospitalized Patients, Sidra Liaquat

Theses & Dissertations

Blood cultures are the gold standard for detecting blood stream infections. However, in the US, 0.6-6% of all blood cultures get contaminated leading to adverse clinical outcomes such as unnecessarily prolonged hospital stay and antibiotic therapy. Using electronic medical records, we explored the clinical outcomes and patient-specific risk factors of contaminated blood cultures in an era where rapid blood culture testing was being utilized to provide blood culture results within hours. Rapid blood culture test results can help clinicians in early and more effective management of patients with contaminated blood cultures, thus improving clinical outcomes. We also studied the impact …

Neural Oscillatory Activity Serving Sensorimotor Control Is Regulated By The Mitochondrial Redox Environment In Health And Disease, Rachel Spooner

Theses & Dissertations

Despite effective regimens of combination antiretroviral therapy, individuals with HIV are still at higher risk for developing forms of cognitive impairment, with one of the most common behavioral abnormalities to manifest being motor dysfunction. This is an important consideration, as deficits in motor control likely contribute to higher-order cognitive impairments, which together, lead to functional dependencies in the ever-growing aging population of HIV-infected adults. While the neuroanatomical bases of motor dysfunction have recently been illuminated in people living with HIV (PLWH), there remains an open question regarding the molecular processes supporting the circuit-level neuronal dynamics that potentially serve these behavioral …

Development Of Long-Acting Antiviral Drug Nanoformulations, Denise Cobb

Theses & Dissertations

Antiretroviral therapy (ART) has improved the quality and duration of life for people living with human immunodeficiency virus (HIV) infection. However, opportunities to improve its profile abound. ART is limited by putative viral reservoir penetrance, emergence of viral mutations, inherent toxicities, and regimen non-adherence. These highlight the need improved drug delivery schemes. Previously, our lab has demonstrated that targeting mononuclear phagocytes for antiretroviral drug delivery extends drug half-life and improves penetrance into viral reservoirs, addressing these limitations of ART. Herein, we developed synthetic and biologic antiretroviral (ARV) drug nanocarriers improve the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of ARVs through …

The Role Of Vgll4 And Mark2-Hdac Axis In Mitosis And Cancer, Yongji Zeng

Theses & Dissertations

The Hippo pathway is an evolutionarily conserved signaling pathway that plays important roles in stem cell biology, tissue homeostasis, and cancer development. The Hippo core signaling pathway features a kinase cascade consisting of mammalian sterile-20 like protein 1/2 (Mst1/2) and large tumor suppressor 1/2 (Lats1/2). Inactivation of the Hippo pathway is correlated with the promotion of proliferation and anti-apoptosis through activation of the transcriptional co-activator Yes-associated protein (YAP). YAP functions through binding with TEA-domain transcription factors (TEAD1–4) to activate target genes.

Vestigial-like 4 (Vgll4) functions as a transcriptional co-repressor in the Hippo-Yes associated protein (YAP) pathway. Vgll4 inhibits cell proliferation …

The Effect Of Polyunsaturated And Saturated Fatty Acids On Seizure Presence And Severity In A Cohort Of Subjects In An Epilepsy Monitoring Unit, Jana K. Wells

Theses & Dissertations

Ketogenic diet therapies (KDTs) have been used to treat epilepsy for nearly 100 years. Although effective, restrictive diet patterns and unknown impacts on long-term health outcomes often prevent their use as first-line therapy. To date, a distinct mechanism of action for KDTs has not been determined and evidence suggests fatty acids (FAs) may play a role in eliciting anti-seizure effects. This dissertation aimed to provide insights into the effect of polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs) on seizure presence and severity through the analysis of dietary intake in a cohort of patients admitted to an epilepsy monitoring …

Multimodal Neuroimaging Of Hiv And Aging, Brandon Lew

Theses & Dissertations

HIV infection remains a significant contributor to disease burden, and with the success of antiretroviral therapies, the population of people with HIV is aging. A growing literature suggests a relationship between HIV-infection and a profile of age advancement, most notably in molecular studies of epigenetics. However, despite the widely-known high prevalence of HIV-related brain atrophy, functional deficits, and HIV-associated neurocognitive disorder (HAND), epigenetic age advancement has not been linked to HIV-related changes in neuroimaging metrics.

We applied three neuroimaging methods, structural MRI, resting state functional MRI, and resting state MEG, to study the brain structure and function of 121 virally-suppressed …

Beyond The Eye: The Neural Signature Of Cerebral Visual Processing In Children With Cerebral Palsy, Jacy R. Hannan

Theses & Dissertations

Cerebral palsy (CP) is a permanent, non-progressive neuromuscular disorder diagnosed early in childhood. Frequently the lesion that causes the motor impairments in individuals with CP concurrently disrupts the visual networks, placing them at a high risk of cerebral visual dysfunctions. Cerebral visual impairment (CVI) often remains unrecognized or misdiagnosed in people with CP. Despite the crucial role of visual function in the development of movement and cognition, the neurophysiological basis of the cerebral visual dysfunctions is almost entirely unknown. This investigation aimed to examine the neurophysiological mechanisms underlying cerebral visual dysfunction in children with CP. Specifically, this research used magnetoencephalographic …