Digital Commons Network^™

Evaluation Of An End-To-End Radiotherapy Treatment Planning Pipeline For Prostate Cancer, Mohammad Daniel El Basha, Court Laurence, Carlos Eduardo Cardenas, Julianne Pollard-Larkin, Steven Frank, David T. Fuentes, Falk Poenisch, Zhiqian H. Yu

Dissertations & Theses (Open Access)

Radiation treatment planning is a crucial and time-intensive process in radiation therapy. This planning involves carefully designing a treatment regimen tailored to a patient’s specific condition, including the type, location, and size of the tumor with reference to surrounding healthy tissues. For prostate cancer, this tumor may be either local, locally advanced with extracapsular involvement, or extend into the pelvic lymph node chain. Automating essential parts of this process would allow for the rapid development of effective treatment plans and better plan optimization to enhance tumor control for better outcomes.

The first objective of this work, to automate the treatment …

Cord Blood-Derived Invariant Natural Killer T Cells As A Platform For Allogeneic Chimeric Antigen Receptor Cell Therapy, Maison Grefe

Dissertations & Theses (Open Access)

Chimeric antigen receptor (CAR) T cells have revolutionized the treatment of hematopoietic malignancies achieving >50% complete response rates in numerous refractory/relapsed B cell malignancies. However, there are challenges that hinder CAR-T efficacy and bar the broader use of this therapy in patients. One approach to address these challenges is to create a safe allogeneic CAR cell product by using cells that do not cause graft versus host disease (GvHD). Invariant natural killer T (iNKT) cells are an ideal candidate as they are restricted to the monomorphic CD1d protein in contrast to HLA restricted αβ-T cells and therefore are safe in …

Exploring The Role Of Il-1Β/Il-1r In The Pathogenesis Of K-Ras Mutant Lung Cancer, Avantika Krishna

Dissertations & Theses (Open Access)

As the leading cause of cancer-related deaths worldwide, the development of targeted therapeutics to treat lung cancer remains crucial. Non-small cell lung cancer (NSCLC), the most common histological subtype predominantly comprises lung adenocarcinoma with driver mutations in the K-ras oncogene (KM-LUAD). KM-LUAD progression partly occurs through activation of the NF-κB pathway initiating an inflammatory response and creating a pro-tumor microenvironment. Notably, the pro-inflammatory cytokine IL-1β a potent activator and product of the NF-κB pathway is elevated in the lungs and sera of KM-LUAD patients. We have shown that IL-1β blockade promotes an anti-tumor immune phenotype in a mouse model of …

Importance Of Specific Nk Cell Subsets For Antitumor Immunity In Hpv+ Cancers, Madison O'Hara

Dissertations & Theses (Open Access)

High-risk type human papillomaviruses (HPV) are associated with genital and oral cancers, and the incidence of HPV+ head and neck squamous cell cancers is fast increasing worldwide. Survival rates for patients with locally advanced disease are poor and variable after standard of care (SOC) treatment. Identifying the antitumor host immune mediators important for treatment response and designing strategies to promote them are essential for improving clinical outcome. The natural killer (NK) cells are a critical component for antitumor innate effector immunity. Among the multitude of activation and inhibitory receptors on immune cells, HLA-DR is recognized as an important activation marker …

Biophysical Model Of Retraction Motor Neurons And Their Modification By Operant Conditioning, Maria Rasheed

Dissertations & Theses (Open Access)

Operant conditioning (OC) is a form of associative learning in which an animal modifies its behavior based on the consequences that follow that behavior. Despite its ubiquity, the underlying mechanisms of OC are poorly understood. Insights into the mechanisms of OC can be obtained by studying Aplysia feeding behavior as it can be modified by OC. This behavior is mediated by a central pattern generator (CPG) network in the buccal ganglia that contains a relatively small number of neurons. This CPG generates rhythmic motor patterns (BMPs) that move food into the gut by closing a tongue-like structure (i.e., radula) during …

High-Dimensional Mediation Analysis Of Multi-Omics Data, Sunyi Chi

Dissertations & Theses (Open Access)

Environmental exposures such as cigarette smoking influence health outcomes through intermediate molecular phenotypes, such as the methylome, transcriptome, and metabolome. Mediation analysis is a useful tool for investigating the role of potentially high-dimensional intermediate phenotypes in the relationship between environmental exposures and health outcomes. Rapid development of high-throughput technologies have made mediation analysis of multi-omics data critical to gain groundbreaking insights into the biological mechanisms underlying the disease etiology. This dissertation aims to develop mediation analysis methods that utilize the enormous amount of multi-omics data in assessing mechanisms of disease etiology. It contains three projects where I propose advanced mediation …

Molecular Mechanisms Of Opioid Use Disorder In Human Brain Models, Emily Mendez

Dissertations & Theses (Open Access)

Opioid use disorder (OUD) is a national and global public health crisis with no end in sight. While studies from animal models hint at widespread epigenetic and transcriptomic alterations of opioid drugs, the molecular consequences of long-term exposure to opioid drugs in human brain is still unclear, and human-centered translational models are necessary to discern the human cell type-specific effects of OUD.

Using postmortem brain Brodmann area 9 (BA9) from the UTHealth Brain Collection for Research on Psychiatric Disorders, I identified angiogenic gene networks perturbed in the RNA and protein of OUD subjects, as well as downregulation of many neuron-correlated …

Syntaxin-3 Mediates Baseline And Stimulated Mucin Secretion, Brianne Wharton

Dissertations & Theses (Open Access)

There are two rates at which airway epithelial cells secrete mucin. The low baseline rate accounts for ciliary clearance, and the high stimulated rate obstructs airways in protection from helminths or in obstructive pulmonary diseases. The exocytosis of mucins occurs via the four-helix SNARE complex. The SNARE proteins contributing helices are the vesicle-SNARE VAMP, and the target-SNAREs SNAP and Syntaxin. Coiling of the complex fuses the granule and plasma membranes to release mucins into the extracellular space. The VAMP and SNAP isoforms mediating baseline and stimulated secretion are known, but the Syntaxin (Stx) isoform remains unknown.

Three candidate exocytic Stx, …

Proof-Of-Concept For Converging Beam Small Animal Irradiator, Benjamin Insley

Dissertations & Theses (Open Access)

The Monte Carlo particle simulator TOPAS, the multiphysics solver COMSOL., and

several analytical radiation transport methods were employed to perform an in-depth proof-ofconcept

for a high dose rate, high precision converging beam small animal irradiation platform.

In the first aim of this work, a novel carbon nanotube-based compact X-ray tube optimized for

high output and high directionality was designed and characterized. In the second aim, an

optimization algorithm was developed to customize a collimator geometry for this unique Xray

source to simultaneously maximize the irradiator’s intensity and precision. Then, a full

converging beam irradiator apparatus was fit with a multitude …

Feasibility And Measurement Of Bedside Pumping In The Nicu: A Mixed Methods Study, Jessica Gomez

Dissertations & Theses (Open Access)

Abstract

Background: Supporting preterm infants with mother’s own milk (MOM) can improve health outcomes and decrease mortality.¹ Freshly pumped MOM, within four hours of expression, has the highest availability of bioactive components versus stored MOM. However, fresh milk is often not readily available due to the disconnected process of breastfeeding that occurs with preterm infants in the NICU. One convenient solution to improve access to fresh MOM is for the mother to pump at the infant's bedside. This intervention could improve the mother's pumping experience and provide the infant access to fresh MOM.

Purpose: This study aimed to evaluate …

Genomic Characterization Of Adolescent And Young Adult Cancers: Investigation Of Ewing Sarcoma Susceptibility And Chornobyl Thyroid Tumors, Olivia Lee

Dissertations & Theses (Open Access)

Adolescent and young adult (AYA) cancers, diagnosed between the ages of 15 and 39, can exhibit distinctive genetic and molecular characteristics. Reported epidemiologic findings and treatment outcomes based on pediatric and adult cancer studies are often not suitable for application to the AYA population, underscoring the need for more thorough genomic research. Advances in sequencing technologies have enabled comprehensive analyses of complex genomic characteristics of AYA cancers, crucial for understanding the underlying biology of these malignancies. Here, I have utilized advanced sequencing techniques and integrated analytic approaches to describe important genomic features in two different AYA cancer types: Ewing Sarcoma …

Development Of Novel Methods To Study Host-Microbe Interactions In The Larval Zebrafish Gastrointestinal Tract, Anh K. Trinh Nguyen

Dissertations & Theses (Open Access)

The dynamic nature and inaccessible location of the intestine pose significant challenges to the study of intestinal physiology and pathology. Zebrafish larvae, possessing optical transparency and genetic tractability, offer an accessible and clinically relevant model for investigating dynamic events in the intestine via time-lapse imaging. In the first part of this work, I discuss our efforts to optimize the parameters of a foodborne infection assay using paramecia as a vehicle. This method provides an effective, high-throughput alternative to infection via immersion or oral gavage, and replicates the most common route of transmission of gastrointestinal (GI) infection in humans. The foodborne …

A Cancer-Specific Study On The Differentially Expressed Protein-Protein Interactions Of Fumarate Hydratase, Sydney Lac

Dissertations & Theses (Open Access)

Fumarate hydratase (FH) is an enzyme used in the Krebs Cycle to convert fumarate to malate, and it is controlled by the FH gene. In this paper, we will investigate its role in Uterine Corpus Endometrial Carcinoma (UCEC) and how FH-deficient cells affect tumorigenesis. It is well-established that FH has been extensively studied in connection with renal cell carcinoma, skin and uterine leiomyomas, pheochromocytoma, and paraganglioma. However, we aim to construct an interaction network of significant genes related to the FH gene under conditions of FH deficiency in the Kreb Cycle. Creating an interactive network that illustrates the interconnectedness of …

Role Of The Immune System In The Modulation Of The Mmr-Deficient Intestinal Stem Cell Niche, Shepard Conner

Dissertations & Theses (Open Access)

Mismatch Repair (MMR) is a crucial DNA repair system to maintain genomic integrity in cells that is integrated by specific genes including MLH1, MSH2, MSH6, and PMS2. These genes play a critical role in repairing errors that occur in base pairing by stabilizing the genetic material. When the MMR system fails to correct those errors, MMR deficiency occurs where monoallelic mutations in the MMR genes result in a condition known as Lynch Syndrome (LS). LS makes up approximately 3% of all colorectal cancer (CRC) and is regarded as a hereditary form of CRC, which progresses from MMR-deficient …

Development Of A Remote Dosimetric Audit Framework For Carbon Therapy, Paige Taylor

Dissertations & Theses (Open Access)

Carbon ion therapy is available at over a dozen institutions around the world and is being employed for treatment of cancer. The increased biological effect of carbon compared to conventional photon-based radiotherapy holds promise for the therapeutic benefit in historically radioresistant tumors. While ion chamber dosimetry has been used for day-to-day clinical measurements of absorbed dose, there are few options for remote dosimetry. The availability of such tools would support the development of a robust remote audit program for carbon ion therapy.

The Imaging and Radiation Oncology Core (IROC) conducts remote audits of photon and proton therapy. These audits are …

Identification And Delineation Of Neuronal Pathways Underlying Hypophagia, Jing Cai

Dissertations & Theses (Open Access)

In terms of metabolism, eating disorders manifest in two extreme directions: overnutrition, which can lead to obesity, and malnutrition, which can result in underweight or even starvation. Both extremes compromise the quality of life. According to the Diagnostic and Statistical Manual of Mental Disorders-5 (DSM-5) standard, eating disorders affect up to 17.9% of young women and 2.4% of young men. Although eating disorders are primarily defined as mental disorders rather than metabolic disorders, they are intertwined with complex emotions and sensory perceptions. However, in contemporary animal research related to eating disorders and feeding behaviors, the majority of neuroscientists still examine …

A Study Of The Snd1/Prmt5 Axis In Liver Cancer By Genetic Mouse Models, Tanner Wright, Tanner Wright

Dissertations & Theses (Open Access)

Arginine methylation is an essential post-translational modification (PTM) in cells. Protein arginine methyltransferase 5 (PRMT5) is the primary enzyme that catalyzes symmetric dimethyl arginine (SDMA) and requires methylosome protein 50 (MEP50) for stability and enzymatic activity which are necessary for life and development. Effector proteins bind different types of PTM’s to facilitate signaling. Staphylococcal nuclease Tudor domain containing 1 (SND1) is an effector that specifically binds SDMA via its single C-terminal Tudor domain. Both SND1 and PRMT5 have been implicated in hepatocellular carcinoma (HCC). SND1 has been confirmed as a driver of HCC using genetically engineered mouse models (GEMMs), though, …

Oncogenic Kras And Telomere Biology In Crc Progression, Ronald Depinho

Dissertations & Theses (Open Access)

While colorectal cancer (CRC) patients diagnosed with localized stage disease (as defined by SEER) have a 5-year survival rate of 90%, this rate plunges to 14% for patients diagnosed with metastatic CRC. Consequently, there is an immediate imperative to elucidate the mechanisms that drive the transition to advanced CRC.

Human CRCs carrying oncogenic mutations in the KRAS oncogene, henceforth referred to as KRAS*, exhibit a 25% higher propensity for developing liver metastases. Similarly, in our CRC mouse model, engineered with an inducible Kras* transgene and conditional null alleles of Apc and Tp53 (referred to as iKAP), KRAS* has been …

Advancing Precision Medicine: Unveiling Disease Trajectories, Decoding Biomarkers, And Tailoring Individual Treatments, Yanfei Wang

Dissertations & Theses (Open Access)

Chronic diseases are not only prevalent but also exert a considerable strain on the healthcare system, individuals, and communities. Nearly half of all Americans suffer from at least one chronic disease, which is still growing. The development of machine learning has brought new directions to chronic disease analysis. Many data scientists have devoted themselves to understanding how a disease progresses over time, which can lead to better patient management, identification of disease stages, and targeted interventions. However, due to the slow progression of chronic disease, symptoms are barely noticed until the disease is advanced, challenging early detection. Meanwhile, chronic diseases …

Operationalizing The Datagauge Framework In A Health Information Exchange Utilizing Hepatitis C Data, Edward Yao

Translational Projects (Open Access)

This project aims to implement the DataGauge framework in a health information exchange (HIE) setting as a proof of concept. The modified DataGauge framework, described by Diaz-Garelli et al. (2019), is utilized to test its functionality and applicability with any dataset. The specific objective of the project is to determine the number of hepatitis C-positive tests within the HIE. The implementation involved multiple iterations following the DataGauge framework's steps for data extraction and analysis. Five iterations were conducted, resulting in both successful and failed queries based on the validity of the data standards. The findings revealed that the HIE, in …

Economic And Policy Determinants Of National Abortion Rates: A Cross-National Study, Olufunke Akiyode

Dissertations & Theses (Open Access)

Abortion is as old as humanity and exists in all cultures. The number and rate of abortions differ among countries and regions of the world. Some determinants of abortion may include economic indicators and policy restrictiveness. This study analyzes the economic and policy determinants of abortion by evaluating the association of income and policy on abortion rates. It uses a panel data regression to examine the association between income, Gini Coefficient and abortion rates. Gini Coefficient measures income inequality, and GNI represents a country’s income. Publicly available longitudinal data obtained from the World Bank, United Nations, United Nations Population Development …

Exploring The Novice Nurses’ Perceptions Of Communication Dynamics In The Operating Room, Lasandra Brown

Dissertations & Theses (Open Access)

Background: Communication among the multidisciplinary team members in an operating room setting is essential for effective and safe patient care. Studies have previously addressed communication breakdowns among team members, and miscommunications have been demonstrated to significantly challenge efficiency in the operating room. Novice nurses play an integral role in the success of operating room procedures and must possess strong communication skills that facilitate optimal patient outcomes.

Purpose: The aim of this study was to explore novice nurses’ perceptions of factors that influence the dynamics of team communication in the operating room setting.

Methods: An inductive thematic, qualitative analysis of 11 …

Symptom Experience Of Patients With Advanced Melanoma Undergoing Immune Checkpoint Inhibitor Therapy, Natalie Jackson-Carroll

Dissertations & Theses (Open Access)

Background: Immune checkpoint inhibitors (ICIs) are novel therapeutic agents utilized in the management of advanced melanoma. Though generally well-tolerated, patients receiving ICIs experience treatment-related toxicities at varying onset and intensity. Assessment and evaluation of these toxicities and their impact on a quality of life is essential to comprehensive cancer care. Patient-reported outcomes (PRO) contribute vital data to a clinical assessment, supporting clinicians in their ability to improve outcomes. To date, there is no melanoma-specific or ICI-specific PRO measure of symptom burden available.

Purpose: The purpose of this study was to describe the symptom experience from the patient's perspective and how …

Baby Boomer Gay Men’S Lived Experiences With Primary Healthcare: A Qualitative Study, Aaron J. Loeb

Dissertations & Theses (Open Access)

Background: Baby boomer gay men have experiences discrimination in healthcare settings. Members of the LGBTQIA+ population are often studied as a single entity, which fails to account for the distinct cultural and social generational differences within this population that may affect their experiences of health care. A paucity of research is available on baby boomer gay men’s perspectives about primary healthcare experiences. Such knowledge is necessary to improve inclusiveness in healthcare settings and health outcomes.

Purpose: The purpose of this study was to describe baby boomer gay men’s lived experiences with primary healthcare. The specific aims are to describe: (1) …

Mental Health And Parenting Among Young Adults Experiencing Homelessness With And Without Their Children, Rebecca Bergh

Dissertations & Theses (Open Access)

Background: Parent-child separation and custody loss are common among parenting young adults experiencing homelessness (YAEH). These experiences may be traumatic for YAEH, a population already vulnerable to mental health disorders and high levels of trauma. Little is known about how YAEH who have their children with them compare to YAEH separated from their children in terms of mental health and risk and resilience factors. Further evidence is needed to better understand the parenting and mental health support needs among YAEH, particularly surrounding parent-child separation.

Aims: This study aimed to examine the characteristics of (1) parenting YAEH living with their children …

The Development Of Artificial Intelligence-Based Tools For Expert Peer Review Of Radiotherapy Treatment Plans, Mary Gronberg

Dissertations & Theses (Open Access)

Creating a patient-specific radiation treatment plan is a time-consuming and operator-dependent manual process. The treatment planner adjusts the planning parameters in a trial-and-error fashion in an effort to balance the competing clinical objectives of tumor coverage and normal tissue sparing. Often, a plan is selected because it meets basic organ at risk dose thresholds for severe toxicity; however, it is evident that a plan with a decreased risk of normal tissue complication probability could be achieved. This discrepancy between “acceptable” and “best possible” plan is magnified if either the physician or treatment planner lacks focal expertise in the disease site. …

Investigating The Role Of Il-10 Producing Nkt Cells In Prevention Of Graft Versus Host Disease, Drew Boagni

Dissertations & Theses (Open Access)

The standard curative treatment for hematologic malignancies is allogeneic stem cell transplantation (ASCT), in which the patient’s immune system is replaced with that of a healthy donor. This can lead to cure through the graft versus leukemia (GVL) effect but can also cause graft versus host disease (GVHD), which is characterized by systemic inflammation and organ damage mediated by dysregulated donor T cells. Preclinical studies have shown invariant natural killer T cells (iNKT) cells can prevent GVHD while preserving GVL. iNKT cells are unconventional T cells which recognize glycolipid antigens presented in the context of CD1d. Upon activation, they secrete …

A Larval Zebrafish (Danio Rerio) Model Of Adherent-Invasive Escherichia Coli Infections, Erika Flores, Erika Flores

Dissertations & Theses (Open Access)

Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, is a broad term for chronic intestinal disorders that severely impact patient morbidity and quality of life. The global prevalence of IBD is rising, with over one million patients affected in the US alone. Adherent-invasive E. coli (AIEC) is a pathobiont frequently found in IBD biopsies. AIEC adhere to and invade epithelial cells, and can survive inside macrophages in vitro. However, how AIEC contributes to IBD in vivo remains unclear. Here a larval zebrafish (Danio rerio) model of AIEC was established, which facilitates the study of the …

Interrogations Of The Tumor Microenvironment Using Magnetic Resonance Imaging, Tianzhe Li

Dissertations & Theses (Open Access)

Both tumor acidosis and tumor hypoxia are characteristics commonly found in the microenvironment of solid malignant tumors. Accurate characterization of the two phenomena could provide important information to clinicians for devising suitable treatment plans. Tumor acidosis and hypoxia are closely linked to each other. Tumor acidosis is caused by the inclination of cancer cells towards anaerobic respiration, and one of the main contributing factors for the avoidance of aerobic respiration is tumor hypoxia. Both phenomena can indicate the high metastatic potential of cancers and can also cause resistance of the cancer systems against anti-cancer therapies. Therefore, developing novel molecular imaging …

Noninvasive Screening Of Nonalcoholic Fatty Liver Disease Among People Living With Hiv, Essi M. Havor

Dissertations & Theses (Open Access)

Background: Nonalcoholic fatty liver disease (NAFLD) disproportionately affects up to 75% of people living with HIV (PLWH). Given the high HIV prevalence in Houston and Harris County, knowledge of the prevalence of NAFLD in PLWH is needed to inform prevention efforts. In addition, such knowledge is required to raise awareness among at-risk individuals and healthcare professionals.

Specific Aims: This cross-sectional study aimed (1) to examine the demographic, behavioral, clinical, and psychosocial characteristics of PLWH in Houston/Harris County, Texas, and to estimate the prevalence of NAFLD, (2) to determine factors associated with the severity of NAFLD, and (3) to identify specific …