Investigating Medical Examiners' Practices: Genetic Evaluation For Fatal Acute Aortic Dissection, Bradley Power

Dissertations and Theses (Open Access)

Acute thoracic aortic dissection (TAD) is a life-threatening event with a hereditary component. Currently, pathogenic variants in 11 genes associated with aortic aneurysm and dissection predispose to a heritable form of disease thereby conferring an increased risk for TAD. Genetic testing plays a pivotal role not only in diagnosis, but also in risk stratification for relatives and medical management to prevent premature death from dissection. Due to its high fatality rate, medical examiners and coroners (ME/Cs) may be the first to identify TAD cases and initiate genetic testing for the decedent and at-risk relatives. ME/Cs were surveyed using three clinical …

Frequency Of Copy Number Variants Involving The Sex Chromosomes In A Clinical Setting, Autumn Vara

Dissertations and Theses (Open Access)

Copy number variants (CNVs) are a common finding in the clinical setting and contribute to both genetic variation as well as disease. Recently, studies have described the accumulation of multiple CNVs as a disease modifying mechanism. While it has been characterized how additional CNVs may play a role in phenotype, in which ways and to what extent sex chromosomes are involved has not been fully described. We performed a secondary data analysis using the DECIPHER database on 2,273 de-identified individuals with 2 CNVs. CNVs were designated primary and secondary based on our criteria and characteristics of both CNV groups were …

Genetic Counselors' Experiences With And Approaches To Discordant Genotypic And Phenotypic Sex Detected Via Non-Invasive Prenatal Testing, Emily Stiglich

Dissertations and Theses (Open Access)

As the use of non-invasive prenatal testing becomes more ubiquitous during pregnancy, genetic counselors (GCs) will see clients more frequently for discordant sex identification via non-invasive prenatal testing (NIPT-DSI). Thus, it is imperative to investigate what GCs consider important when counseling about NIPT-DSI and assess how GCs perceive their role in such cases. Prenatal and pediatric GCs were surveyed regarding previous experiences of NIPT-DSI, comfort levels of topics relating to NIPT-DSI, and perceived importance of potential discussion topics in a counseling session (n = 108). The survey consisted of two vignettes, presenting cases of NIPT-DSI identified prenatally in one …

Development Of Fully Balanced Ssfp And Computer Vision Applications For Mri-Assisted Radiosurgery (Mars), Jeremiah Sanders

Dissertations and Theses (Open Access)

Prostate cancer is the second most common cancer in men and the second-leading cause of cancer death in men. Brachytherapy is a highly effective treatment option for prostate cancer, and is the most cost-effective initial treatment among all other therapeutic options for low to intermediate risk patients of prostate cancer. In low-dose-rate (LDR) brachytherapy, verifying the location of the radioactive seeds within the prostate and in relation to critical normal structures after seed implantation is essential to ensuring positive treatment outcomes.

One current gap in knowledge is how to simultaneously image the prostate, surrounding anatomy, and radioactive seeds within the …

Identification And Molecular Analysis Of Dna In Exosomes, Jena Tavormina

Dissertations and Theses (Open Access)

Exosomes are heterogeneous nanoparticles 50-150nm in diameter. Exosomes contain many functional cargo components, such as protein, DNA, and RNA. While protein and RNA exosome content has been extensively studied, very little work has been done to characterize exosomal DNA. Here, we demonstrate that exosomal DNA is heterogeneous and its packaging into exosomes is dependent on the cell of origin. Furthermore, through a rigorous assessment of various isolation methods, we identify Size Exclusion Chromatography (SEC) as the best method for the isolation of exosomal DNA for downstream applications. Additionally, we evaluate the methylation status of exosomal DNA and demonstrate that exosomal …

The Gsk-3Β-Fbxl21 Axis Regulates Tcap Via Ubiquitin-Mediated Proteasomal Pathway In The Cytoplasm, Jiah Yang

Dissertations and Theses (Open Access)

Protein turnover is one of the most essential mechanisms controlling circadian rhythms. F-Box and Leucine Rich Repeat Protein21 (FBXL21) is a circadian E3 ligase which shows oscillatory mRNA transcripts and protein levels. It was previously found to perform subcellular compartment-specific E3 ligase activities targeting the core clock proteins CRYPTOCHROME(CRY)1/2. Here we identified a new sarcomeric target substrate, Telethonin(TCAP), which also shows circadian oscillation in its mRNA transcript and protein expression and, importantly, interaction with FBXL21 in an anti-phasic manner. Via computational and pharmacological tests, we identified Glycogen Synthase Kinase-3β(GSK-3β) as a regulator of FBXL21. Biochemical and molecular characterizations demonstrated that …

Evaluating The Therapeutic Efficacy Of Grb2 Inhibition In Ovarian Malignancies, Olivia Lara

Dissertations and Theses (Open Access)

Purpose: Adaptor proteins such as growth factor receptor-bound protein-2 (Grb2) play important roles in cancer cell signaling. In the present study, we examined the biological effects of liposomal antisense oligodeoxynucleotide that blocks Grb2 expression (L-Grb2) in ovarian cancer models.

Experimental Design: Murine orthotopic models of ovarian cancer (OVCAR5 and SKOV3ip1) were used to study the biological effects of L-Grb2 on tumor growth. In vitro experiments (cell viability assay, Western blot analysis, siRNA transfection, and reverse phase protein array) were carried out to elucidate the mechanism and potential predictors of tumor response to L-Grb2.

Results: Treatment with L-Grb2 decreased tumor growth …

Modeling Proton Relative Biological Effectiveness Using Monte Carlo Simulations Of Microdosimetry, Mark A. Newpower

Dissertations and Theses (Open Access)

Proton therapy is a radiotherapy modality that can offer a better physical dose distribution when compared to photon radiotherapy by taking advantage of the Bragg peak, a narrow region of rapid energy loss. Proton therapy is also known to offer an enhanced relative biological effectiveness (RBE) compared to photons. In the current clinical standard, RBE is fixed at 1.1 at all points along the proton beam, meaning protons are assumed to require 10% less dose than photons to achieve target coverage and organ at risk (OAR) sparing. However, there is mounting clinical evidence, and a significant number of in vitro …

Oxidative Phosphorylation: A Critical Feature And Novel Therapeutic Target In Melanoma Brain Metastases, Grant Fischer

Dissertations and Theses (Open Access)

We recently showed via RNA-sequencing (RNA-seq) analysis of clinical samples that melanoma brain metastases (MBMs) have higher expression of oxidative phosphorylation (OXPHOS) genes (including PPARGC1A or PGC1α) than patient-matched extracranial metastases (ECMs). Thus, the central hypothesis of this dissertation is that OXPHOS plays a critical role in the pathogenesis of MBMs.

RNA-seq analysis identified increased expression of OXPHOS genes in intracranial (ICr) vs. subcutaneous (SQ) xenografts of 4 different human melanoma cell lines. Increased OXPHOS in the ICr xenografts was confirmed by direct metabolite analysis and [U-¹³C]-glucose tracing analysis. Together, these studies indicate that the brain TME …

Exploring The Potential Yield Of Prenatal Testing By Evaluating A Postnatal Population With Structural Abnormalities, Peyton Busby

Dissertations and Theses (Open Access)

After identification of one or more structural abnormalities in a fetus, pregnant women are offered a host of different testing options to identify a possible genetic cause for the structural abnormality(ies). When considering what type of test to undertake, there is limited information on the diagnostic yield of the varying testing options. Some women may miss an opportunity to gain the information they are seeking or make a less informed decision when they choose a testing option after identification of a structural abnormality due to this lack of information. This study aimed to identify the potential diagnostic yield of all …

The Impacts Of Insurance And Billing Considerations On The Practice And Attitudes Of Genetic Counselors, Emily Krosschell

Dissertations and Theses (Open Access)

Genesurance counseling has been identified as an integral part of many genetic counseling sessions, but little is known about the workflow impacts and genetic counselor perceptions of genesurance-related tasks. In this study, we aimed to characterize how insurance and billing considerations for genetic testing are being incorporated into genetic counselors’ practice; as well as describe current attitudes and challenges associated with their integration. An electronic survey was sent by email to members of the National Society of Genetic Counselors (NSGC). A total of 325 genetic counselors that provided direct patient care were included in data analysis. Results showed that the …

Intratumoral Sting Activation Sensitizes Poorly Immunogenic Cancers To Checkpoint Blockade Immunotherapy, Casey Ager

Dissertations and Theses (Open Access)

Unprecedented durable tumor regression can be achieved in patients with checkpoint blockade immunotherapy, yet these responses are rare and are not observed in all tumor types. Castration resistant prostate cancer (CRPC) and pancreatic adenocarcinoma (PDAC) are two common lethal cancers that remain refractory to checkpoint blockade, requiring development of new therapeutic approaches to promote responsivity in patients with these diseases. Both CRPC and PDAC are characterized by an immunosuppressive tumor milieu rich in cells of the myeloid lineage, which regulate T cell activity in many ways independent of the coinhibitory receptor axis. We investigated whether activation of acute inflammatory signaling …

Development And Implementation Of A Homogeneous And A Heterogeneous Anthropomorphic End To End Quality Assurance Audit System Phantom For Magnetic Resonance Guided Radiotherapy Modalities Ranging From 0.35 T To 1.50 T, Angela Steinmann

Dissertations and Theses (Open Access)

Introduction: Magnetic resonance (MR) guided radiation therapy (MRgRT) is an emerging field that integrates an MR imager with either a linear accelerator or three radioactive cobalt-60 sources. Before institutions participate in multi-institutional NCI-sponsored clinical trials, they are required to perform a credentialing test provided by IROC-Houston. During the credentialing test, end-to-end phantoms are used to evaluate the institution’s ability to perform consistent and accurate radiation treatments. IROC-Houston’s conventional anthropomorphic phantoms are not visible in MR, thus they are insufficient for MRgRT systems. The purpose of this work was to create an anthropomorphic thorax and a head and neck (H&N) phantom …

Equipment To Address Infrastructure And Human Resource Challenges For Radiotherapy In Low-Resource Settings, Rachel Mccarroll

Dissertations and Theses (Open Access)

Millions of people in low- and middle- income countries (LMICs) are without access to radiation therapy and as rate of population growth in these regions increase and lifestyle factors which are indicative of cancer increase; the cancer burden will only rise. There are a multitude of reasons for lack of access but two themes among them are the lack of access to affordable and reliable teletherapy units and insufficient properly trained staff to deliver high quality care. The purpose of this work was to investigate to two proposed efforts to improve access to radiotherapy in low-resource areas; an upright radiotherapy …

Improved Target Coverage Of Spinal Metastases Through The Use Of Flattening Filter Free Beams, Laura Bennett

Dissertations and Theses (Open Access)

Of the patients that are diagnosed with metastatic disease, up to 40% will develop vertebral osseous metastases. These metastases tend to be located in close proximity to the spinal cord itself, making it difficult to achieve the recommended minimum dose of 14 Gy for single fraction SBRT or 21 Gy¹ for three fraction SBRT while maintaining acceptable doses to the cord and cauda equina. This proximity of the target to critical structures has the potential to compromise the efficacy of the radiation treatment plan in favor of reducing normal tissue dose, resulting in poor local control and tumor recurrence …

Outcomes Of Genetic Testing In A Genitourinary Genetics Clinic, Annelise Pace

Dissertations and Theses (Open Access)

Several known hereditary cancer syndromes confer an increased risk for genitourinary (GU)related malignancies. Various guidelines indicate when to refer patients to genetic counseling for GU-related hereditary cancer syndromes but there is limited research on the clinical picture of these patients, including their cancerous and non-cancerous features, the genetic testing strategy for this population, and the probability of having a positive germline mutation if testing is performed. The purpose of this study is to determine the most common indications for ordering genetic testing in a GU Genetics Clinic and evaluate whether there is a relationship between the indication for genetic testing …

Tumor Immunotherapy: Mechanisms Of Acquired Resistance And Characterization Of Immune Related To Xicities, Ashvin Jaiswal

Dissertations and Theses (Open Access)

Tumor immunotherapy has shown very promising clinical benefit across an array of cancers; however, two major challenges remain unresolved in the field. First, many patients do not respond to therapy at all or relapse after a period of remission. Second, there are often dose-limiting immune related adverse effects associated with immunomodulation.

In order to understand the mechanisms employed by tumors to evade immunotherapeutic responses, we established a murine model of melanoma designed to elucidate the molecular mechanisms underlying immunotherapy resistance. Through multiple in vivo passages, we selected a B16 melanoma tumor line that evolved complete resistance to combination blockade of …

Development Of 3d-Printed Patient Specific Bolus For Clinical Use In To Tal Scalp Irradiation, Garrett Baltz

Dissertations and Theses (Open Access)

Total scalp irradiation (TSI) is a specialized radiation therapy technique that aims to deliver a uniform dose to the entire scalp. Original electron-based TSI techniques had limited homogeneity due to hot and cold spots created at field junctions due to the multiple matched fields that were required to treat the entire scalp. The transition to photon volumetric-modulated arc therapy based TSI techniques has improved homogeneity, to the point where non-conformal bolus is now a limiting factor. Bolus is required to build-up full dose to the scalp surface in total scalp irradiation. Creating bolus that is conformal to the scalp is …

Integrative Cancer Immunogenomic Analysis Of Serial Melanoma Biopsies Reveals Correlates Of Response And Resistance To Sequential Ctla-4 And Pd-1 Blockade Treatment, Whijae Roh

Dissertations and Theses (Open Access)

Melanoma is the most malignant form of skin cancer. The five-year survival rate for metastatic melanoma is 19.9%. Although targeted therapy of BRAF and MEK inhibitors were developed for melanoma, resistance to therapy is inevitable. Immune checkpoint blockade, which reverses the suppression of the immune system, on the other hand, has shown a durable response in 20-30% of patients with metastatic melanoma. However, more predictive and robust biomarkers of response to this therapy are still needed, and resistance mechanisms remain incompletely understood. To address this, we examined a cohort of metastatic melanoma patients treated with sequential checkpoint blockade against cytotoxic …

Memory Potential, Molecular Characterization, And Translational Applications Of The Novel Theo/Tceo T Cell Phenotype, Todd Bartkowiak, Todd Bartkowiak

Dissertations and Theses (Open Access)

T cells comprise a substantial arm of the immune system and are exquisitely adapted to combat pathogens and tumors. The inflammatory environment largely dictates the nature of T cell response. A hallmark of T cell-mediated immunity is formation of immunological memory; the ability to respond more potently to re-encounter with pathogens. The immune system is also capable of recognizing tumors as foreign, much like viral or bacterial pathogens. Tumors have evolved, though, to generate an immunosuppressive environment to avoid destruction. The field of immunotherapy seeks to overcome immune suppression, in part by targeting T cell co-receptors on the cell surface …

Impact Of Kras/Nras Mutational Heterogeneity On Clinical Outcomes In Colorectal Cancer, Jonathan M. Loree

Dissertations and Theses (Open Access)

Introduction: Mutations in KRAS/NRAS (RAS) predict a lack of benefit from anti-EGFR agents in metastatic colorectal cancer (mCRC). As next generation sequencing (NGS) has advanced, we are discovering atypical and low allele frequency mutations. We aimed to evaluate how NGS can optimally define RAS mutant CRC and the role of relative mutant allele frequency (rMAF) as a biomarker.

Methods: Using institutional and public cohorts of mCRC patients with NGS results, we described the prevalence and clinical impact of atypical (not in current guidelines) and low rMAF RAS mutations (RAS MAF by the MAF of the mutated gene with …

Dynamic Assessment Of Nk Cell Interactions With Pediatric Tumor Cells To Predict Response To Immunotherapy, Arianexys Aquino Lopez

Dissertations and Theses (Open Access)

Due to Natural Killer (NK) cells’ capacity to target tumor cells without prior sensitization, adoptive NK cell therapy represents a promising immunotherapy approach for pediatric cancer patients. Our laboratory has developed an NK cell expansion protocol that generates large quantities of NK cells for therapeutic infusion. Given that NK cells are heterogeneous, with variable receptor expression and potential to target tumor cells, the purpose of my study was to determine whether subpopulations of NK cells with enhanced anti-tumor potential could be identified for increased potency of the NK cell infusion product. In addition, we previously showed that our expanded NK …

Modeling Post Stroke Respiratory Dysfunction, Apneas And Cognitive Decline, Anthony Patrizz

Dissertations and Theses (Open Access)

Modeling Post Stroke Respiratory Dysfunction,

Apneas and Cognitive Decline

Anthony Patrizz, B.A.

Advisory Professor: Louise McCullough M.D., Ph.D.

Stroke is a major cause of mortality and the leading cause of long-term disability in the US. More than 60% of individuals suffering a first time stroke develop respiratory dysfunction, prolonging recovery and increasing mortality. Post-stroke cognitive decline is a major contributor to disability and nursing home placement, therefore the cognitive consequences of Stroke Induced Respiratory Dysfunction (SIRD) need to be explored if we hope to enhance functional recovery. The first step towards treatment of the negative consequences of SIRD is the …

Membrane Bound Il21 Promotes Natural Killer Cell Expansion Through Mir 124-3p Mediated Regulation, Anitha Somanchi

Dissertations and Theses (Open Access)

Natural Killer (NK) cells are cells of the innate immune system that act as first line of defense against viral infections and participate in tumor immune surveillance. NK cells do not cause graft versus host disease (GvHD), or require prior antigen exposure to exert anti-tumor activity, hence are an attractive choice for immunotherapy applications. Owing to small numbers of NK cells in peripheral blood (1-32%, with a 6% median), ex vivo expansion of NK cells is critical for NK cell adoptive immunotherapy, various expansion platforms have been explored over the decades. We developed a robust platform for ex vivo expansion …

Identifying The Immune Related Metabolic Properties Of Pancreatic Cancer Using Nuclear Magnetic Resonance Spectroscopy And Dynamic Magnetic Resonance Spectroscopic Imaging With Hyperpolarized Pyruvate, Joseph Weygand

Dissertations and Theses (Open Access)

Despite its relatively low incidence, pancreatic cancer was the fourth leading cause of cancer-related death in the US in 2015. This is due in part to pancreatic cancer’s natural resistance to both chemotherapy and radiotherapy. Immunotherapy presents an attractive potential treatment approach, but initial trials in mice have proved ineffective. Because cancer cells exhibit a significant increase in metabolic activity relative to normal tissue, an understanding of the metabolic function of tumors in systems with different levels of immunocompetence is a critical first step to develop an understanding of the immune-related metabolic properties of the tumor, which have potential application …

High-Throughput Mapping Of The Biological Effects Of Particle Therapy, Lawrence Bronk

Dissertations and Theses (Open Access)

Radiation therapy is an essential tool in the cure of many cancer patients. Charged particle based radiation therapies are gaining momentum as the physical dose distributions of ions are superior to standard photons due their limited range. Additionally, charged particle radiation has been shown to have linear energy transfer (LET) specific relative biological effectiveness (RBE) when compared to photons. It is essential to employ accurate biophysical models for particle beams in order to maximize the therapeutic potential of particle therapy through the introduction of biologically optimized treatment planning. The development of such models requires the support of large amounts of …

Volumetric, Magnetic Resonance-Visible, And Radiation-Sensitive Detectors For Magnetic Resonance Image-Guided Radiation Therapy, Hannah J. Lee

Dissertations and Theses (Open Access)

VOLUMETRIC, MAGNETIC RESONANCE-VISIBLE, AND RADIATION-SENSITIVE DETECTORS FOR MAGNETIC RESONANCE IMAGE-GUIDED RADIATION THERAPY

Hannah Jungeun Lee

Advisory Professor: Geoffrey S. Ibbott, Ph.D.

Due to the superior soft-tissue contrast of magnetic resonance imaging (MRI) compared to conventional computed tomography (CT) and other on-board imaging techniques, several groups have integrated MRI and radiation treatment machine systems. The advent of MR image-guided radiation therapy (MR-IGRT) using systems, such as the 1.5 MRI – 7 MV linear accelerator (MR-Linac), now allow for improved soft-tissue on-board imaging for patient position and tumor target localization verification and the ability to assess functional biological tissue characteristics with MRI, …

Parp Inhibitor Upregulates Pd-L1 Expression And Enhances Cancer-Associated Immunosuppression, Shiping Jiao

Dissertations and Theses (Open Access)

With recent approvals for therapeutic antibodies that block CTLA4, PD-1 and PD-L1, immune checkpoints have emerged as new targets in cancer therapy. In addition, there is accumulating evidence highlighting the role of cancer-associated immunity in patient response to cytotoxic anticancer agents. Inhibitors of poly (ADP-ribose) polymerase (PARP) have shown substantial cytotoxic effects against tumors with defects in DNA damage responses. However, whether a crosstalk between PARP inhibition and immune checkpoints exists remains unclear. Here, it has been shown that PARP inhibitors (PARPis) upregulate PD-L1 expression in multiple cancer cell lines, human xenograft tumors, and syngeneic mouse tumors. Mechanistically, PARPi inactivates …

Managing Variant Discrepancy In Hereditary Cancer: Clinical Practice, Barriers, And Desired Resources, Ellen Zirkelbach

Dissertations and Theses (Open Access)

Variants are changes in the DNA whose phenotypic effects may or may not be definitively understood. Because variant interpretation is a complex process, sources sometimes disagree on the classification of a variant, which is called a variant discrepancy. This study aimed to determine the practice of genetic counselors regarding variant discrepancies and to identify the barriers to counseling a variant discrepancy in hereditary cancer genetic testing. This investigation was unique because it was the first to address variant discrepancies from a clinical point of view. An electronic survey was sent to genetic counselors in the NSGC Cancer Special Interest Group. …

Genesurance Counseling: Patient Perspectives, Chelsea Wagner

Dissertations and Theses (Open Access)

Genetic counselors (GCs) have recently reported an increase in the discussion of insurance-related, or “genesurance,” topics during genetic counseling sessions. Despite increasing frequency, little knowledge exists about genesurance conversations and patient expectations. This study aimed to assess patient expectations of GCs in genesurance discussions and evaluate if health insurance literacy impacted these expectations. A 38-item survey, including a validated tool to assess health insurance literacy (HIL) was administered prior to patients receiving prenatal or cancer genetic counseling at three participating institutions. A total of 360 responses were analyzed. Key variables were compared using chi-square analysis and multivariable logistic regression was …