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Dual-Criterion Dose Finding Designs For Phase I Clinical Trials, Yunlong Yang

Dissertations and Theses (Open Access)

The primary objective of Phase I oncology trials is to assess the safety and tolerability of novel therapeutics. Conventional dose escalation methods identify the maximum tolerated dose (MTD) based on dose-limiting toxicity (DLT). However, as cancer therapies have evolved from chemotherapy to targeted therapies, these traditional methods have become problematic. Many targeted therapies rarely produce DLT and are administered over multiple cycles, potentially resulting in the accumulation of lower-grade toxicities, which can lead to intolerance, such as dose reduction or interruption. To address this issue, we proposed dual-criterion designs that find the MTD based on both DLT and non-DLT-caused intolerance. …

Immune Landscape Of Early Liver Metastatic Lesions In A Novel Immunocompetent Murine Colorectal Cancer Metastasis Model, Alaa Mohamed

Dissertations and Theses (Open Access)

Colorectal cancer minimal residual disease (MRD) represents a major clinical problem for colorectal cancer patients, with failure rates of surgery and adjuvant chemotherapy between 5% to 40% depending on stage of disease. In our study, we simulated MRD using genetically engineered organoids with precise somatic editing of APC and TP53, creating a murine model that mimics human liver metastatic colorectal cancer. By implementing a meticulously timed experimental metastatic model, we could detect microscopic tumor lesions. Through genomic and transcriptomic analyses, we pinpointed the importance of macrophages, particularly those expressing high levels of CSF1R, in these microscopic metastatic focal lesions. We …

Unraveling Epigenetic Mechanisms That Regulate Breast Cancer Lung Metastatic Relapse By Rewiring The Immune Microenvironment, Jayanta Mondal

Dissertations and Theses (Open Access)

Metastasis accounts for >90% of cancer-related deaths and thwarting metastasis is widely considered to be the “Holy Grail” of cancer treatment. Breast cancer is the most common cause of cancer-related death among women and is characterized by its proclivity to spread to distant secondary organs like the lungs, and the brain. These disseminated tumor cells lie dormant at the secondary site and can undergo metastatic relapse. Epigenetic alterations are a predominant hallmark of cancer, however, its role in facilitating reawakening of dormant cancer cells and the subsequent metastatic relapse remains to be elucidated. To address this gap of knowledge, we …

Impact Of Tumor Cell Expressed Cd38 On Metastasis And Immune Evasion In Breast Cancer, Tanvi Visal

Dissertations and Theses (Open Access)

Triple-negative breast cancer (TNBC) is a highly metastatic breast cancer subtype. The epithelial-to-mesenchymal transition (EMT) of cancer cells is a key feature of the metastatic cascade and is not a binary process but often generates malignant cells with both epithelial (E) and mesenchymal (M) traits known as hybrid EM cells. Recent studies highlight the enhanced metastatic potential of the hybrid EM cells. However, molecular insights and targetable vulnerabilities within hybrid EM remain elusive. We discovered that hybrid EM murine tumors are enriched in CD38, an immunesuppressive molecule associated with worse clinical outcomes in liquid malignancies but relatively understudied in solid …

Evaluating Cancer Rates, Cancer Types, And Variant Hotspots Between Different Races And Ethnicities In Individuals With Li-Fraumeni Syndrome, Hillary Esplen

Dissertations and Theses (Open Access)

Li Fraumeni Syndrome (LFS) is a cancer predisposition syndrome that increases the risk for numerous cancer types in both children and adults. In the general population, incidence rates for various cancer types differ among races and ethnicities. Although a few germline TP53 pathogenic/likely pathogenic (P/LP) variants in those with LFS have been studied and associated with specific populations, such as the South and Southeast Brazil founder variant, p.Arg337His, there still lacks research on the variable expressivity of cancers within the LFS population based on specific variant, race and/or ethnicity. This study aims to describe the specific TP53 germline variants, the …

Relationship Between Processing Body Formation, Epithelial-To-Mesenchymal Transition, And Invasion In Lung Adenocarcinoma, Amanda Warner

Dissertations and Theses (Open Access)

Lung cancer is the leading cause of cancer-related deaths in the United States, largely due to its ability to metastasize. Epithelial-to-mesenchymal transition (EMT) is a process that enhances the ability of cells to lose their cell-cell contacts, invade, and enter the blood stream which are essential during metastasis. Many transcriptional gene programs are altered during EMT such as activation of mesenchymal transcription factors, like ZEB1, and enhanced response to the TGFβ1 cytokine. In oncogenic contexts, TGFβ1 enhances the formation of processing-bodies (P-bodies) where P-body proteins are required for invasion in multiple cancerous cell lines. P-bodies are a type of ribonucleoprotein …

Rod Photoreceptor Regeneration In A Zebrafish Model With Retinitis Pigmentosa, Eyad Shihabeddin

Dissertations and Theses (Open Access)

A cellular hallmark of inherited retinal degenerative diseases is progressive loss of photoreceptors until one is completely blind. Unlike mammalian models, Zebrafish have the ability to naturally regenerate their neurons after injury or disease is detected. We have generated a zebrafish model with the most common autosomal dominant form of the inherited retinal degenerative disease known as Retinitis Pigmentosa. We utilize immunohistochemistry, single-cell RNA sequencing, several analysis tools, behavioral assays and oligonucleotides to characterize our zebrafish model and identify the transcription factors necessary for rod photoreceptor regeneration. We show that our zebrafish model has continuous degeneration and regeneration of rod …

Automated Radiotherapy Treatment Planning For Breast Cancer: A Robust To Ol For Global Deployment, Hana Baroudi

Dissertations and Theses (Open Access)

Breast cancer incidence continues to rise worldwide, particularly in low- and middle-income countries, where limitations in resources already constrain access to timely care. Radiotherapy is a cornerstone of breast cancer management, proven to significantly lower both recurrence and mortality. However, a growing shortage of radiation staff worldwide threatens the prompt delivery of these treatments.This thesis proposes an automated solution to address the limited accessibility of radiotherapy planning in breast cancer management by developing an end-to-end automated treatment planning model and evaluating its performance and limitations across diverse patient populations.

An automated contouring model was trained using data from 104 whole-breast …

Exploring Veto Activity: Dnam-1-Cd155 Axis In Overcoming Nk Cell-Mediated Allo-Rejection And Applications For Car-T Cell Therapy, Wei-Hsin Liu

Dissertations and Theses (Open Access)

As Miller et al. defined veto activity, it enables cells to target host cytotoxic T lymphocyte (CTL) precursors specific to veto cells' antigens, selectively eliminating anti- donor T cell clones without inducing rejection. By leveraging this unique immune property, two key research aims were proposed: “Exploration of the Impact of Veto Activity on Natural Killer (NK) Cell-Mediated Allo-rejection” and “Development of Off-the- shelf Chimeric Antigen Receptor (CAR)-T Therapy: Engineering Anti-Viral Veto CD8+ T Cells”. As demonstrated in our previous research, in a murine model with mild conditioning, anti-third-party central memory CD8+ veto T cells (veto Tcm) can prevent T cell- …

The Gut Microbiome As A Novel Approach For Reversing Long-Term Inflammation And Accelerated Aging Across The Lifespan, Janelle M. Korf

Dissertations and Theses (Open Access)

Introduction: Neonatal hypoxic-ischemic encephalopathy (HIE) arises from disrupted perinatal cerebral oxygenation and perfusion. It is a leading global cause of infant death and disability which disproportionally affects males. Like adult stroke, HIE initiates a rapid influx of inflammatory cells across the blood brain barrier and a loss of microglial homeostasis. Persistent peripheral inflammation in children with a history of HIE is recognized but its ramifications, including accelerated aging, are poorly understood. As this coincides with critical stages of brain development, interventions started months or years post-injury may still improve survivors’ quality of life. One promising intervention is to manipulate the …

Development Of Lineal Energy Spectrum-Based Biological Effects Models For Protons, Joseph M. Decunha, Fada Guan, David Grosshans, Zhongxing Liao, Dragan Mirkovic, Oleg Vassiliev, Radhe Mohan

Dissertations and Theses (Open Access)

In this dissertation, methods are developed and described to allow for the rapid calculation of microdosimetric spectra (specifically, lineal energy) for protons. SuperTrack, a GPU-accelerated tool for calculation of microdosimetric spectra was developed and is capable of computing lineal energy spectra up to 5000x faster than using Geant4 directly. Proton lineal energy spectra generated by SuperTrack are indistinguishable from those generated by Geant4. With SuperTrack, large libraries of lineal energy spectra for monoenergetic protons spanning 0-300 MeV have been developed. The proton lineal energy spectra calculated by SuperTrack have been compared to experimental measurements made by a tissue equivalent proportional …

Novel Statistical Methods For Mediation Analysis With High-Dimensional Omics Mediators, Zhichao Xu

Dissertations and Theses (Open Access)

Mediation analysis is a widely used statistical method for examining how molecular traits, such as gene or protein expression, act as intermediaries linking an exposure to a health outcome. For example, it can help explain how smoking affects disease risk through molecular changes. The rapid progress in high-throughput omics profiling technologies and large-scale epidemiology consortia, such as the Trans-Omics for Precision Medicine (TOPMed) program from the National Heart, Lung and Blood Institute (NHLBI) and UK Biobank, now has resulted in an extensive accumulation of genomic data for biomedical research and analysis. At the same time, it poses significant methodological challenges, …

Overcoming Resistance To Cdk4/6-Targeted Therapy Using Jak2/Stat3 Inhibitor In Triple-Negative Breast Cancer, Chuling Zhuang

Dissertations and Theses (Open Access)

Breast cancer is the most common type of cancer diagnosed in women, with nearly 30% of cases becoming metastatic accounting for over 90% of breast cancer-related deaths. Among different breast cancer subtypes, triple-negative breast cancer (TNBC) has the worst prognosis and the highest propensity to metastasize. However, TNBC patients have limited treatment options due to their lack of actionable drug targets while therapeutic resistances result in high rates of recurrence and metastasis. Cyclin-dependent kinase 4 and 6 (CDK4/6) are major cell cycle regulators that control G1 to S phase transition and aberrant hyperactivation of the CDK4/6 pathway results in uncontrolled …

Combined Inhibition Of Lysine-Specific Demethylase 1 And Kinase Signaling As A Preclinical Treatment Strategy In Glioblastoma, Lea Stitzlein

Dissertations and Theses (Open Access)

Glioblastoma is the most common primary malignant brain tumor in adults, with limited treatment options resulting in a poor prognosis. Lysine-specific demethylase 1 (LSD1) is overexpressed in glioblastoma and contributes to tumor growth and treatment resistance. Inhibitors of LSD1 have shown preclinical promise but have had limited clinical development for glioblastoma. Given the frequent kinase pathway alterations in glioblastoma, the interplay between LSD1 inhibition and kinase signaling pathways was investigated to identify vulnerabilities that could be exploited through rationally designed combination therapies. We hypothesized that LSD1 inhibitors would activate kinase signaling pathways, such as MAPK, and the addition of kinase …

Impact Of Personal And Family History Of Huntington's Disease On The Decision And Ability To Obtain Life, Long-Term Care, And Disability Insurance, Karli Livingston

Dissertations and Theses (Open Access)

Huntington’s disease (HD) is an inherited, neurodegenerative condition characterized by a clinical triad of motor, cognitive, and psychiatric symptoms. Individuals diagnosed with HD manifest characteristic symptoms of the disease including motor and cognitive changes, and they may or may not have undergone genetic testing to confirm the diagnosis. Individuals at-risk for HD are those who have not yet undergone genetic testing for HD, but have a first- or second- degree relative diagnosed with the disease. Genetic testing for HD is categorized into two forms: predictive and confirmatory. However, many individuals choose not to pursue testing due to a fear of …

The Influence Of Scientific, Genetic, And Health Literacy On Carrier Screening Decision-Making, Brenna D. Albracht

Dissertations and Theses (Open Access)

For those wishing to assess their reproductive risks and make informed decisions in their reproductive planning, carrier screening for autosomal recessive and X-linked conditions, as well as cell-free DNA (cfDNA) screening for aneuploidy, are recommended during pregnancy. Despite similarities in purpose, sample requirements, insurance coverage, and safety, a lower percentage of individuals elect carrier screening than cfDNA screening, suggesting there may be a disconnect in what patients perceive as valuable information for their pregnancy. Previous studies have attempted to explain the factors associated with carrier screening uptake or decline; however, no models have yet accounted for a patient’s literacy level …

Achieving The Practice-Based Competencies: Are More Than 50 Cases Needed?, Farren Lopez

Dissertations and Theses (Open Access)

Genetic counseling graduate programs are required to provide didactic coursework and fieldwork experiences to foster development of the practice-based competencies (PBCs) in trainees. Currently, every graduating trainee must log a minimum of 50 participatory encounters to demonstrate readiness for entry-level practice of the PBCs. Previous studies have noted that many trainees exceed the 50-case standard, raising the question of whether this minimum satisfies the training needs of every student. To assess the perceived number of encounters needed for graduates to independently perform the PBCs, a survey was administered to 2023 and 2024 graduates of North American genetic counseling training programs. …

Role Of Mir-4732-3p In Breast Cancer Brain Metastasis And Brain Metastatic Tumor Microenvironment, Munazza Samar Khan

Dissertations and Theses (Open Access)

In this study, we aimed to identify microRNAs (miRNAs) that may play important roles in breast cancer brain metastasis (BCBM). To this end, we conducted miRNA-sequencing of extracellular vesicles isolated from the serum samples of 6 BCBM patients and 8 Stage I/II/III breast cancer patients, and identified 49 circulating miRNAs that were upregulated in BCBM patients compared to Stage I/II/III breast cancer. Upon further analysis, we identified miR-4732-3p to be upregulated in brain-tropic triple-negative breast cancer (TNBC) cell lines, compared to parental lines. MiR-4732-3p overexpression increased metastatic properties of TNBC cells, including proliferation, migration, invasion, and maintenance of a mesenchymal …

"Magic Computer In The Sky" - Participant Perspectives On Control And The Genetic Counseling Admissions Match, Jessica Clark

Dissertations and Theses (Open Access)

Since the 2018 admissions cycle, genetic counseling graduate programs in North America have utilized the Genetic Counseling Admissions Match (GCAM), a Match algorithm to place applicants. While a study prior to implementation found that most students were uninterested in a Match due to concerns of control, there has been no investigation into matched applicants’ experiences since its inception. A mixed-methods study explored the experiences and perceptions of control of genetic counselors and genetic counseling (GC) students who entered a program following the GCAM. An anonymous survey documenting GCAM experience and a validated measure for locus of control (LOC) was disseminated …

Exploring The Immunologic Consequences Of Atrx Deficiency In Glioma, Benjamin Whitfield

Dissertations and Theses (Open Access)

ATRX is a key chromatin regulator that is frequently mutated across multiple cancer types. One of the most common ATRX-mutated tumor types is the adult-type glioma, IDH-mutant, Astrocytoma. It is known that ATRX mutation leads to increases in DNA damage, replication stress, and global epigenetic regulation at a cell level; however, less is known about the impact of ATRX mutation on immune signaling. Furthermore, little is known about the interaction of ATRX loss with gain-of-function mutations in IDH. In this paper we set out to explore the impact of ATRX loss on immune signaling in gliomas, both in the context …

Investigating Prefrontal Cortex Neuronal Signatures Of Opioid-Induced Risk-Taking Behavior, Cana Quave

Dissertations and Theses (Open Access)

Opioid use disorder occurs alongside impaired risk-related decision-making, but the underlying neural correlates are unclear. We developed an approach-avoidance conflict task using a modified conditioned place preference procedure to study neural signals of risky opioid seeking in the prefrontal cortex, a region implicated in executive decision-making. Following morphine conditioned place preference, rats underwent a conflict test in which fear-inducing cat odor was introduced in the previously drug-paired side of the apparatus. While the saline-exposed control group avoided cat odor, the morphine group included two subsets of rats that either maintained a preference for the paired side despite the presence of …

Stat3, Nf-Κb, And Estrogen Receptor Beta: The Balance Of Inflammation In K-Ras Mutant Lung Adenocarcinoma, Michael J. Clowers

Dissertations and Theses (Open Access)

K-ras mutant lung adenocarcinoma (KM-LUAD) is a difficult-to-treat cancer subtype in which chronic inflammation pervades the tumor immune microenvironment (TIME). Pro-inflammatory pathways dampen the response to treatments, including immune checkpoint inhibitors, necessitating therapies that target this inflammatory signaling network in the TIME. This network is underpinned by interaction and coordination of two inflammatory pathways: signal transducer and activator of transcription 3 (STAT3) and nuclear factor kappa B (NF-κB). The balance of these transcription factors determines the degree of anti- vs. pro-tumor immunity, and a skewing towards STAT3 is known to promote tumor development and a pro-tumor TIME. It is also …

Automated To Ols For Contour Review In Radiotherapy, Barbara Marquez

Dissertations and Theses (Open Access)

Peer review of organ-at-risk and target volume delineation is essential for patient safety and optimization of treatment outcomes. Peer review makes a substantial impact on patient outcomes, reporting notable rates of plan changes when reviewed and worse survival when patient cases are not reviewed. In around half of revised cases, target volume change is the required cause for modification (related to tumor control); in one in ten cases, it is normal tissue sparing (related to treatment toxicity). Essentially all North American institutions with accredited residency training programs hold peer review to some capacity. However, accessibility to practicing routine peer review …

Evaluating Triage To Genetic Counseling Using An Online Reproductive Genetics Module, Grace Ra

Dissertations and Theses (Open Access)

The American College of Obstetricians and Gynecologists recommends genetic screening for all pregnant women. As clinical recommendations broaden and demand for prenatal screening increases, obstetric practitioners report time constraints and lack of genetics knowledge as challenges to providing sufficient pretest education. These challenges in offering routine screening are further compounded by the inequities in access to genetic counseling and testing. Thus, alternative education and service delivery models have emerged to meet the demands for prenatal genetics education and help mitigate challenges surrounding access. At UTHealth Houston, an online triage and education module, the Prenatal Genetics Education Program (PGEP), was created …

Denial Of Inpatient Genetic Testing: A Study On Outpatient Yield And Outcomes, Cindy Y. Canales

Dissertations and Theses (Open Access)

This study investigates the difference in diagnostic yield between patients approved for inpatient genetic testing compared to those denied inpatient testing and the effect of an earlier diagnosis on outcomes and medical/clinical care. In the literature, research has explored the impact of a diagnostic delay for patients with genetics conditions, assessed the utility of genetic testing in the inpatient setting, and described the impact to care of an earlier diagnosis. However, gaps remain on research exploring the diagnostic yields of inpatient versus outpatient settings and the potential impact to care an inpatient genetic testing request denial may pose. This is …

Differential Progression Of Pancreatic Premalignancy In Geographically Distant Murine Transgenic Cohorts Uncovers Key Role Of Microbial Metabolites, Rian M. Howell

Dissertations and Theses (Open Access)

Cancer is a leading cause of death worldwide. Despite recent advances in diagnostic and therapeutic modalities, pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer that remains highly lethal. Efforts have been made to increase the understanding of the underlying mechanisms driving early stages of tumor development, when the cancer is most susceptible to intervention. To this end, genetically engineered mouse models (GEMMs) have been developed with the mutations most commonly seen in the patient population. Expression of these mutations in select cellular compartments has resulted in the ability to recapitulate characteristics of human pancreatic cancer such as the development of …

The Dynamics Of Power Transfer In Organizations: Examining Downward Deference And Its Workplace Consequences, Hoang Bao My Nguyen

Dissertations and Theses Collection (Open Access)

This dissertation examines managerial power transfer as a core mechanism through which less-hierarchical management unfolds in organizations. While traditional management research has emphasized formal authority and top-down control, emerging organizational forms increasingly call on managers to share power with subordinates. Despite growing interest in constructs like empowerment, delegation, and participative leadership, the phenomenon of power transfer remains conceptually fragmented and undertheorized.

To address this, the dissertation defines power transfer as the intentional redistribution of authority, control, or resources by powerholders to lower-power individuals. Chapter 1 develops a typology of power transfer behaviors, organized along two key dimensions: extent of control …

The Sheriff's Constitution, Farhang Heydari

Vanderbilt Law School Faculty Publications

The county sheriff is unique among our nation's law enforcers, with an ancient pedigree, elected status, and special protections as a state constitu- tional officer. But these factors combine to cause a recurrent problem elected sheriffs often assert for themselves the power to refuse to enforce criminal laws of their choosing. Today's constitutional sheriffs-a group of sheriffs who view themselves as the highest authority in their county, answerable only to their electorate-are the latest manifestation of this ethos, declaring opposition to gun control measures, pandemic restric- tions, environmental protections, and more. Lest one think these nonen- forcement decisions are entirely …

Valuing Heat-Related Mortality Risks, W. Kip Viscusi, Clayton J. Masterman

Vanderbilt Law School Faculty Publications

Heat-related mortality risks are a substantial component of the looming costs of climate change in the United States and globally. This article presents the results from a risk-risk survey to test whether U.S. respondents place a valuation premium on mortality risks from heat relative to cancer and transportation risks. The questionnaire exploits exogenous shocks to temperatures during a heat wave and randomized elements to further test whether preferences vary with heat exposure or the age of individuals exposed to heat risks. The results provide strong evidence that there is no valuation premium in the U.S. for heat-related risks. Subjects valued …

Torts Mismatches, Edward K. Cheng

Vanderbilt Law School Faculty Publications

In torts, the damages required for full compensation of the victim and optimal deterrence of the injurer are normally the same. This correspondence is perfectly natural: If the injurer fully compensates the victim, then the injurer will completely internalize his externalities. Yet sometimes full compensation and optimal deterrence do not align. A well-known example is punitive damages, in which victims are purposely overcompensated to optimally deter injurers. What the literature has failed to acknowledge is that these torts mismatcheswhen full compensation of victims and optimal deterrence of injurers are incompatibleoccur elsewhere and explain controversial and unresolved doctrinal areas of torts. …