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Commissioning & Daily Qa Of Converted Linac For Electron Flash, Tomaj Javidtash

Theses and Dissertations

Ultra-high dose rate (FLASH) radiotherapy has demonstrated promising normal tissue sparing in preclinical studies; however, the lack of standardized dosimetry, commissioning, and quality assurance (QA) methodologies remains a major barrier to its reproducible and safe implementation. In particular, conventional clinical commissioning and QA protocols are not directly applicable at FLASH dose rates due to challenges associated with detector response, dose-per-pulse effects, and beam control limitations.

This thesis presents the commissioning of a converted Varian 21EX linear accelerator for electron FLASH operation within the Division of Medical Physics at the Virginia Commonwealth University (VCU) Department of Radiation Oncology. Comprehensive beam characterization …

Establishing A Conventional Linac-Based Electron Flash Beam, Justin Defrancisco

Theses and Dissertations

Problems: A rediscovered radiotherapy technique, FLASH, involves increasing the dose rate to >40 Gy/s. For a given dose, FLASH is shown to decrease the normal tissue complication probability without affecting the tumor control probability. More preclinical studies are necessary to confirm and enable these desirable properties on humans. Current preclinical investigations have diverse constraints, requiring FLASH apparatuses with flexible parameters and accurate control. However, there are limited FLASH platforms available, the existing ones are costly. Our institution is not in possession of any such infrastructure. Even if available, dosimetry and beam control in FLASH are extremely lacking. There is …

Investigating The Protein Interactome Of Escherichia Coli To Understand Metabolic Regulation When Proteins Bind: A Systems Biology Study., Shomeek Chowdhury

Theses and Dissertations

Proteins bind other proteins and work together as machines to perform many biological functions. Metabolic enzymes governing the life-sustaining metabolic reactions and therefore, metabolism are proteins which also binds other proteins. In this dissertation work, I have explored proteins when they interact with metabolic enzymes, play any role in regulating the cell’s metabolism. I study this phenomenon in Escherichia coli whose protein-protein interaction data is readily available in public databases with proper reference to the experimental study. Another good reason is the predictions we make in this computational study can be tested and validated in E. coli as it is …

Monte-Carlo Method For Identifying Aberrantly Expressed Genes In Cancer, Matthew M. Beltran

Theses and Dissertations

Gene expression provides insight into the functional variations on the cellular level that shape biological phenomena. Several recent sequencing technologies have produced an abundance of expression profiles spurring entirely new disciplines of biological study. With this myriad of data, the new task is deciding how to assess and extract meaningful insights. Identifying genes with expression changes in disease conditions is often the first step in finding potential biomarkers for diagnosis, and targets for pharmaceutical treatments. Parametric statistical tests at the individual gene level have been the conventional approach for finding differentially expressed genes. These tests exhibit high statistical power but …

The Type Iv Pilus Secretin Bfpb: Structural Analysis And Binding Interactions, Janay I. Little

Theses and Dissertations

Enteropathogenic Escherichia coli (EPEC) causes severe diarrhea in young children. The type IV pilus (T4P) of EPEC, known as the bundle-forming pilus (BFP), plays an important role in EPEC pathogenesis. T4Ps are a family of surface appendages that are important for adhesion, colonization, biofilm formation, virulence, twitching motility and many other functions. One essential component of the BFP system is the secretin, BfpB. Secretins are a large family of integral outer membrane proteins found in T4Ps as well as type II and type III secretion systems, and filamentous phages. Details of the secretin structure have been limited to the overall …

A Personal History Of The Department Of Biology, Margaret L. May

VCU University History Books

Former faculty member Margaret May recounts the history and development of the Department of Biology at Virginia Commonwealth University.

Development Of Analytical Methods For Analysis Of Glycosaminoglycans And Their Mimetics In Human Plasma, Rawan M. Fayyad

Theses and Dissertations

Glycosaminoglycans (GAGs) are linear, polydisperse polysaccharides consisting of alternating amino sugars and either a uronic acid or galactose residue. They are ubiquitous components of the extracellular matrix and are present on cell surfaces and in basement membranes. GAGs are highly negatively charged as a result of many sulfate and carboxylic acid groups, and are extremely heterogeneous in both their structure and in their physicochemical properties. This complexity in structure is attributed to the alterations in residue types, glycosidic bond linkage, sulfation levels, sulfation positions, and chain lengths during biosynthesis. GAGs interact with a wide number of proteins and modulate various …

Exploring The Dopamine Transporter Utilizing A Two-Pronged Approach With Novel Cathinone Analogs And Mutant Dopamine Transporters, Charles B. Jones Iii

Theses and Dissertations

The dopamine transporter (DAT) is responsible for the removal of the neurotransmitter from the synaptic gap and a therapeutic target for a multitude of drugs. While the ortholog Drosophila melanogaster dopamine transporter (dDAT) and human serotonin transporter (hSERT) have resolved structures, the human dopamine transporter (hDAT) does not. A 3-D computational homology model of hDAT was constructed for the study of molecular interactions with agents within the central binding site (S1) of the transporter.

Synthetic cathiones are a class of abused stimulant drugs that primarily target DAT. Greater than 150 cathinones have been identified on the clandestine market but there …

Development Of Sam-Based Chemical Probes For Methyltransferases, Daniel V. Mongeluzi

Theses and Dissertations

Fig.1. SAM analog for the profiling of MTase activity. A. Chemical structure of probe 1; B. General scheme of the labeling and capture strategy.

A

B

Methylation is a fundamental mechanism used in the biological system to modify the structure and function of biomolecules such as proteins, DNA, RNA, and metabolites.¹ Methyl groups are installed by a large and diverse class of S-adenosyl-L-methionine (SAM)-dependent methyltransferases (MTases), which transfer the sulfonium methyl group of SAM to either carbon, nitrogen, oxygen, or other heteroatoms on biomolecules.² Dysregulated MTase activity contributes to numerous diseases, including cancer, metabolic disorders, neurodegenerative diseases. …

The Roles And Benefits Of Using Undergraduate Student Leaders To Support The Work Of Summit-P, Janet Bowers, Bryan D. Poole, Caroline Maher-Boulis, Ashley Schwartz, Angelica Bloomquist, Erica Slate Young

Journal of Mathematics and Science: Collaborative Explorations

The article by Poole, Turner, and Maher-Boulis (2020) describes one way in which undergraduates have been used to support the SUMMIT-P goal of investigating examples of how mathematics and statistics are applied in partner discipline courses. Two other universities in the SUMMIT-P consortium, San Diego State University and Oregon State University, also use undergraduates in different ways to support the work of integrating science applications into math classes. In this article, we compare and contrast these three uses to further highlight this somewhat untapped resource.

Heparan Sulfate. A Ligand For Coordination Compounds., Eric Ginsburg

Theses and Dissertations

Heparan sulfate (HS), a type of glycosaminoglycan (GAG), has been identified as a ligand for interactions with polynuclear platinum complexes (PPCs). HS is involved in numerous biological processes, and often considered to be extracellular DNA. PPCs interact with HS through the formation of a “sulfate clamp”, where multiple anionic sulfate groups cluster around the cationic PPC. The masking of HS results in the inhibition of enzymatic activity, protein-HS interactions, and other biological processes. PPCs use HS proteoglycans as an method of cellular internalization. By targeting sulfated-GAGs, PPCs can offer precision medicine not currently observed with the FDA approved platinum therapies. …

Resolution Of Proximal Oxidative Base Damage And 3′-Phosphate Termini For Nonhomologous End Joining Of Free Radical-Mediated Dna Double-Strand Breaks, Sri Lakshmi Chalasani

Theses and Dissertations

Clustered damage to DNA is a signature mark of radiation-induced damage, which involves damage to the nucleobases and/or DNA backbone. Double-strand breaks created by damaging agents are detrimental to cell survival leading to chromosomal translocations. Normal cells employ Non-homologous end-joining because of its faster kinetics, to suppress chromosomal translocations. However, the presence of complex DNA ends constitutes a significant challenge to NHEJ. Location of Thymine glycol (Tg) at DSB ends was a potential hindrance to end joining. The substrate with Tg at the third position (Tg3) from the DSB joined better than when present at the fifth position (Tg5). However, …

The Development Of Novel Inhibitors Of The Nlrp3 Inflammasome, Jacob W. Fulp

Theses and Dissertations

Inflammasomes are intracellular multimeric protein complexes that regulate inflammation by controlling the maturation of cytokines, interleukin-1β (IL-1β) and interleukin-18 (IL-18). Additionally, activation of these inflammasome complexes has been implicated in an inflammatory form of death known as proptosis. Of the known inflammasomes, the NOD-like receptor family pyrin domain containing 3 (NLPP3) inflammasome, is the most elucidated. Under physiological conditions, NLRP3-mediated inflammation promotes healing and the elimination of cellular debris and pathogens. However, the dysregulation of IL-1β, IL-18 and pyroptosis are instrumental in the development of multiple pathologies. Furthermore, studies suggest that the NLRP3 inflammasome mediates detrimental neuroinflammation and …

An Investigation Of Electronic Cigarette Aerosol Mixture On Craniofacial Development In Mouse Embryos, Suraj Kandalam

Theses and Dissertations

E-cigarette (e-cig) use has increased in recent years among teenagers and young adults. E-cigs are battery-powered nicotine delivery systems that vaporize e-liquids, a solution composed of propylene glycol (PG), vegetable glycerin (VG), nicotine, flavoring, and coloring agents. The aim of this study was to determine the effects of exposure to e-cig aerosol mixtures (e-cigAMs) on proliferation, migration, and differentiation of NCCs in vitro and craniofacial development in mouse embryos in vivo. E-cigAM was produced by bubbling e-cig aerosol into saline. E-cigAMs were generated for unflavored e-liquid of increasing PG: VG ratio. Metabolic activity (MA), gene expression, migration, and proliferation …

Hydrogen Sulfide Regulation Of Kir Channels, Junghoon Ha

Theses and Dissertations

Inwardly rectifying potassium (Kir) channels establish and regulate the resting membrane potential of excitable cells in the heart, brain and other peripheral tissues. Phosphatidylinositol- 4,5-bisphosphate (PIP2) is a key direct activator of ion channels, including Kir channels. Gasotransmitters, such as carbon monoxide (CO), have been reported to regulate the activity of Kir channels by altering channel-PIP2 interactions. We tested, in a model system, the effects and mechanism of action of another important gasotransmitter, hydrogen sulfide (H2S) thought to play a key role in cellular responses under ischemic conditions. Direct administration of sodium hydrogen sulfide (NaHS), as an exogenous H2S source, …

A Roadmap For Development Of Novel Antipsychotic Agents Based On A Risperidone Scaffold, Urjita H. Shah

Theses and Dissertations

Schizophrenia is a chronic psychotic illness affecting ~21 million people globally. Currently available antipsychotic agents act through a dopamine D₂ receptor mechanism, and produce extrapyramidal or metabolic side effects. Hence, there is a need for novel targets and agents. The mGlu₂/5-HT_2A receptor heteromer has been implicated in the action of antipsychotic agents, and represents a novel and attractive therapeutic target for the treatment of schizophrenia. A long-term goal of this project is to synthesize bivalent ligands where a 5-HT_2A receptor antagonist is tethered to an mGlu₂ PAM via a linker.

The goals of the …

Exploration Of Bivalent Ligands Targeting Putative Mu Opioid Receptor And Chemokine Receptor Ccr5 Dimerization, Christopher K. Arnatt, Bethany A. Falls, Yunyun Yuan, Thomas J. Raborg, Ruturaj R. Masvekar, Nazira El-Hage, Dana E. Selley, Anthony V. Nicola, Pamela E. Knapp, Kurt F. Hauser, Yan Zhang

Medicinal Chemistry Publications

Modern antiretroviral therapies have provided HIV-1 infected patients longer lifespans and better quality of life. However, several neurological complications are now being seen in these patients due to HIV-1 associated injury of neurons by infected microglia and astrocytes. In addition, these effects can be further exacerbated with opiate use and abuse. One possible mechanism for such potentiation effects of opiates is the interaction of the mu opioid receptor (MOR) with the chemokine receptor CCR5 (CCR5), a known HIV-1 co-receptor, to form MOR-CCR5 heterodimer. In an attempt to understand this putative interaction and its relevance to neuroAIDS, we designed and synthesized …

Interactomics-Based Functional Analysis: Using Interaction Conservation To Probe Bacterial Protein Functions, J. Harry Caufield

Theses and Dissertations

The emergence of genomics as a discrete field of biology has changed humanity’s understanding of our relationship with bacteria. Sequencing the genome of each newly-discovered bacterial species can reveal novel gene sequences, though the genome may contain genes coding for hundreds or thousands of proteins of unknown function (PUFs). In some cases, these coding sequences appear to be conserved across nearly all bacteria. Exploring the functional roles of these cases ideally requires an integrative, cross-species approach involving not only gene sequences but knowledge of interactions among their products. Protein interactions, studied at genome scale, extend genomics into the field of …

Curcumin/Melatonin Hybrids As Neuroprotective Agents For Alzheimer's Disease, John Saathoff

Theses and Dissertations

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the leading cause of dementia, affecting ~5.2 million Americans. Current FDA approved medications provide mainly symptomatic relief and there are no agents available to delay or cure this disease. Multiple factors such as amyloid-β aggregates, dyshomeostasis of biometals, oxidative stress, and neuroinflammation have been implicated in the development of AD. Even though significant advances have been made in understanding the mechanisms leading to AD, the exact etiology still remains elusive. Given AD’s multifactorial nature, a multifunctional strategy of small molecule design would help to identify novel chemical templates. Recently our lab …

Momentum Clinic For Teen And Young Adult Cancer Patients, Merian O'Neil

Theses and Dissertations

This study explores the needs of teen and young adult cancer patients undergoing long-term chemotherapy treatments and the design of an outpatient clinic that accommodates this population’s unique needs. Most teens endure long-term treatments in a pediatric facility targeted primarily for children, while others are treated in adult facilities. Teens have different privacy and social needs than children, and while they are not adults, they are involved in their own treatment decisions, unlike children. The target age group for this study is teens and young adults, ages thirteen to twenty-two. A common theme emerged from research and interviews conducted in …

A Study Of The Action Of Risperidone At 5-Ht2a Receptors, Supriya A. Gaitonde

Theses and Dissertations

Risperidone is an ‘atypical’ antipsychotic and is approved by the USFDA mainly for the treatment of schizophrenia and symptoms of bipolar disorder. Risperidone (an SDA or serotonin-dopamine antagonist) has ~20-fold higher affinity at 5-HT_2A receptors over dopamine D₂ receptors, which makes it more efficacious against the negative symptoms of schizophrenia and less liable to causing extrapyramidal side effects than ‘typical’ antipsychotics.

The major goal of the current investigation was to study the structure of risperidone and to identify the minimum structural features required for 5-HT_2A receptor affinity that retain antagonist action. The structure of risperidone was systematically …

Anticancer Activity Of A Thymidine Quinoxaline Conjugate Is Modulated By Cytosolic Thymidine Pathways, Qiong Wei, Haijuan Liu, Honghao Zhou, Dejun Zhang, Zhiwei Zhang, Qibing Zhou

Medicinal Chemistry Publications

Background

High levels of thymidine kinase 1 (TK1) and thymidine phosphorylase (TYMP) are key molecular targets by thymidine therapeutics in cancer treatment. The dual roles of TYMP as a tumor growth factor and a key activation enzyme of anticancer metabolites resulted in a mixed outcome in cancer patients. In this study, we investigated the roles of TK1 and TYMP on a thymidine quinoxaline conjugate to evaluate an alternative to circumvent the contradictive role of TYMP.

Methods

TK1 and TYMP levels in multiple liver cell lines were assessed along with the cytotoxicity of the thymidine conjugate. Cellular accumulation of the thymidine …

Generation Of Multicellular Tumor Spheroids With Microwell-Based Agarose Scaffolds For Drug Testing, Xue Gong, Chao Lin, Jian Cheng, Jiansheng Su, Hang Zhao, Tianlin Liu, Xuejun Wen, Peng Zhao

Chemical and Life Science Engineering Publications

Three dimensional multicellular aggregate, also referred to as cell spheroid or microtissue, is an indispensable tool for in vitro evaluating antitumor activity and drug efficacy. Compared with classical cellular monolayer, multicellular tumor spheroid (MCTS) offers a more rational platform to predict in vivo drug efficacy and toxicity. Nevertheless, traditional processing methods such as plastic dish culture with nonadhesive surfaces are regularly time-consuming, laborious and difficult to provide uniform-sized spheroids, thus causing poor reproducibility of experimental data and impeding high-throughput drug screening. In order to provide a robust and effective platform for in vitro drug evaluation, we present an agarose scaffold …

Generation Of Multicellular Tumor Spheroids With Microwell-Based Agarose Scaffolds For Drug Testing, Xue Gong, Chao Lin, Jian Cheng, Jiansheng Su, Hang Zhao, Tianlin Liu, Xuejun Wen, Peng Zhao

Chemical and Life Science Engineering Publications

Three dimensional multicellular aggregate, also referred to as cell spheroid or microtissue, is an indispensable tool for in vitro evaluating antitumor activity and drug efficacy. Compared with classical cellular monolayer, multicellular tumor spheroid (MCTS) offers a more rational platform to predict in vivo drug efficacy and toxicity. Nevertheless, traditional processing methods such as plastic dish culture with nonadhesive surfaces are regularly time-consuming, laborious and difficult to provide uniform-sized spheroids, thus causing poor reproducibility of experimental data and impeding high-throughput drug screening. In order to provide a robust and effective platform for in vitro drug evaluation, we present an agarose scaffold …

Differential Expression Analysis Of Rna Sequencing Data By Incorporating Non-Exonic Mapped Reads, Hung-I Harry Chen, Yuanhang Liu, Yi Zou, Zhao Lai, Devanand Sarkar, Yufei Huang, Yidong Chen

Human and Molecular Genetics Publications

Background

RNA sequencing (RNA-seq) is a powerful tool for genome-wide expression profiling of biological samples with the advantage of high-throughput and high resolution. There are many existing algorithms nowadays for quantifying expression levels and detecting differential gene expression, but none of them takes the misaligned reads that are mapped to non-exonic regions into account. We developed a novel algorithm, XBSeq, where a statistical model was established based on the assumption that observed signals are the convolution of true expression signals and sequencing noises. The mapped reads in non-exonic regions are considered as sequencing noises, which follows a Poisson distribution. Given …

Studies On Rationally Designed, Allosteric, Coagulation Inhibitors, Rio Boothello

Theses and Dissertations

Heparin is a natural allosteric modulator, with numerous structural and conformational variations leading to many reports of bleeding complications and variations in anticoagulant effects. A flurry of research has been directed towards understanding this puzzle. This work entails the utilization of three unique strategies to further our understanding of this complex issue. Traditional synthetic, biosynthetic and biophysical approaches have failed to conquer the GAG-protein complexity. Computational analysis however could serve as a powerful approach to decipher this dilemma. A dual filter algorithm was incorporated to identify unique hexasaccharide sequences for HCII and AT. Our experimental studies exhibit a good correlation …

Toward A Robust Computational Screening Strategy For Identifying Glycosaminoglycan Sequences That Display High Specificity For Target Proteins, Nehru Viji Sankaranarayanan, Umesh R. Desai

Medicinal Chemistry Publications

Glycosaminoglycans (GAGs) interact with many proteins to regulate processes such as hemostasis, cell adhesion, growth and differentiation and viral infection. Yet, majority of these interactions remain poorly understood at a molecular level. A major reason for this state is the phenomenal structural diversity of GAGs, which has precluded analysis of specificity of their interactions. We had earlier presented a computational protocol for predicting “high-specificity” GAG sequences based on combinatorial virtual library screening (CVLS) technology. In this work, we expand the robustness of this technology through rigorous studies of parameters affecting GAG recognition of proteins, especially antithrombin and thrombin. The CVLS …

Cxcr4 Inhibition Ameliorates Severe Obliterative Pulmonary Hypertension And Accumulation Of C-Kit+ Cells In Rats, Daniela Farkas, Donatas Kraskauskas, Jennifer Drake, Aysar A. Alhussini, Vita Kraskauskiene, Harm J. Bogaard, Carlyne D. Cool, Norbert F. Voelkel, Laszlo Farkas

Internal Medicine Publications

Successful curative treatment of severe pulmonary arterial hypertension with luminal obliteration will require a thorough understanding of the mechanism underlying the development and progression of pulmonary vascular lesions. But the cells that obliterate the pulmonary arterial lumen in severe pulmonary arterial hypertension are incompletely characterized. The goal of our study was to evaluate whether inhibition of CXC chemokine receptor 4 will prevent the accumulation of c-kit+ cells and severe pulmonary arterial hypertension. We detected c-kit+­ cells expressing endothelial (von Willebrand Factor) or smooth muscle cell/myofibroblast (α-smooth muscle actin) markers in pulmonary arterial lesions of SU5416/chronic hypoxia rats. We found increased …

Isolation And Characterization Of Multipotent Lung Stem Cells From P53 Mutant Mice Models, Venkat Sundar Gadepalli

Theses and Dissertations

Recent advances in understanding lung biology have shown evidence for the existence of resident lung stem cells. Independent studies in identifying and characterizing these somatic lung stem cells have shown the potential role of these cells in lung repair and regeneration. Understanding the functional characteristics of these tissue resident stem/progenitor cells has gained much importance with increasing evidence of cancer stem cells, cells in a tumor tissue with stem cell characteristics. Lung cancer is most commonly characterized by loss of p53 function which results in uncontrolled cell divisions. Incidence of p53 point mutations is highest in lung cancer, with a …

Characterization Of A Putative Tonb Deficient Porphyromonas Gingivalis Mutant, Soheil Rostami

Theses and Dissertations

Porphorymonas gingivalis is one of the major bacterial pathogens responsible for the initiation and progression of periodontal disease. The bacterium requires hemin uptake for its growth and has developed sophisticated mechanisms to extract hemin from hemin containing proteins in the oral cavity. Hemin first binds to receptors on the surface of P. gingivalis and is then taken up in an energy dependent manner. TonB is an inner membrane bound protein that spans the periplasm and is believed to be involved in the passage of hemin through the double membrane of P. gingivalis. However, the TonB protein in P. gingivalis is …