Medical Sciences Commons^™

Design, Synthesis, And Evaluation Of Small Molecules In The Discovery Of Novel Antimicrobial Agents, Kimberly D. Grimes

Theses and Dissertations (ETD)

The increasing prevalence of antibiotic-resistant bacteria, including Mycobacterium tuberculosis, Streptococcus pneumoniae, Staphylococcus aureus, and Enterococcus faecalis, pushes us to discover new antibacterial agents to maintain adequate patient coverage. This body of work highlights the use of medicinal chemistry methodologies that encompass cross-disciplinary fields of study. Chapter 1 gives an introduction to the antibacterial drug targets, resistance, and how scientists are working to overcome obstacles encountered with drug-resistant bacteria. It also details modern medicinal chemistry applications in antimicrobial drug discovery. Chapter 2 details the use of a structure-guided library approach to drug design, in which large virtual libraries against the target …

The N-Terminal Domain Of The Y-Box Binding Protein Yb-1 Plays A Major Role In Cell Proliferation And Apoptosis, Payal Khandelwal

Theses and Dissertations (ETD)

Y-box binding protein, YB-1, is a member of the cold shock domain superfamily of proteins. It is involved in a plethora of cellular functions, including cell proliferation. The molecular mechanisms governing the involvement of YB-1 in cell proliferation are still unclear. Earlier studies done in chicken pre-B lymphocyte DT-40 cells in our laboratory have shown that a targeted disruption in one allele of chicken YB-1

(Chk-Yb-1b) gene at its N-terminal domain resulted in multiple abnormalities in the heterozygous mutants, including slower growth rate, abnormal cell morphology, increased cell size, increased genomic DNA content and significant changes in levels of cell …

The Structural And Functional Study Of Git1 Paxillin Binding Domain, Ziwei Zhang

Theses and Dissertations (ETD)

The G protein coupled receptor (GPCR)-kinase (GRK) interacting protein 1 (GIT1) is a multidomain protein that plays an important role in cell adhesion, motility, cytoskeletal remodeling, and membrane trafficking. GIT1 mediates the localization of p21-activated kinase (PAK) and PAK-interactive exchange factor (PIX) to focal adhesions, and its activation is regulated by the interaction between its C terminal paxillin-binding domain (PBD) and the LD motifs of paxillin.

In this dissertation, we determined the solution structure of rat GIT1 PBD by nuclear magnetic resonance (NMR) spectroscopy. The PBD folds into a four-helix bundle, which is structurally similar to the focal adhesion targeting …

Tetraspanin Kai1/Cd82 Inhibits Cell Migration-Related Cellular Events Via Reorganizing Actin Network, Wei Liu

Theses and Dissertations (ETD)

To determine how tetraspanin KAI1/CD82, a tumor metastasis suppressor, inhibits cell migration, we assessed which motility-related cellular events are altered by KAI1/CD82 and how KAI1/CD82 regulates these events. We found that KAI1/CD82-overexpressing cancer cells exhibit various morphologies but typically display elongated cellular extensions and a lack of lamellipodia. Live imaging demonstrated that the formation of lamellipodia and retraction of extensions were deficient upon KAI1/CD82 overexpression.

The deficiency in developing motility-related cellular events was accompanied by defects in actin cortical network and stress fiber formations. Notably, actin polymerization was attenuated by KAI1/CD82. Although Rac1 activity was diminished upon KAI1/CD82 expression, Rac1 …

Uncovering P53 Mutations And Abnormal Gene Expression In Pediatric Adrenocortical Cancer, Alina Nico West

Theses and Dissertations (ETD)

Pediatric adrenocortical cancer is extremely rare and often fatal (approximately 0.3-0.4 cases per million worldwide; 50% 5-year survival). The incidence of pediatric adrenocortical cancer in southern Brazil is 10-15 times higher than the worldwide incidence. Due to the rarity of adrenocortical cancer, especially in children, underlying gene dysregulation and mechanisms of tumorigenesis of the adrenal gland are very poorly described in the literature. However, it is well-known that the tumor suppressor p53, which is mutated in over 50% of all human cancers, is commonly mutated in pediatric adrenocortical cancer. In addition, evidence strongly suggests that if a child has adrenocortical …

Humanized Chimeric Receptors In The Therapy Of Multiple Sclerosis, Ioana Moisini

Theses and Dissertations (ETD)

The role of autoreactive, antigen-specific T-cells in the development of autoimmunity has long been documented. T-cells expressing chimeric receptors are specifically redirected against such cells and have been proven to suppress autoimmune encephalomyelitis, the murine model of multiple sclerosis. We here demonstrate the ability of humanized chimeric receptors to suppress experimental autoimmune encephalomyelitis (EAE) in a humanized mouse model by redirecting T lymphocytes against autoreactive T-cells. The receptors were synthesized by linking the 84-102 epitope of human myelin basic protein (MBP) to the extracellular and transmembrane domains of the beta chain of human major histocompatibility complex (MHC) class II molecule …

Neuroadaptive Changes In The Mesocortical Glutamatergic System During Nicotine Self-Administration And After Extinction In Rats, Fan Wang

Theses and Dissertations (ETD)

The mesocorticolimbic pathway is critical in almost all aspects of drug abuse, including nicotine. Though many of the neurochemical and molecular effects of nicotine have been well studied, nicotine’s long-term neuroadaptive effects, specifically within the mesocorticolimbic pathway, are largely undefined. Thus, in current study, we determined the neuroadaptive changes in the mesocortical glutamatergic system during chronic nicotine self-administration (SA), which emulates important aspects of nicotine intake by humans, and after extinction. In the initial study, after 18 days of nicotine SA, in the medial prefrontal cortex (mPFC), NMDA receptor subunit 2A (NR2A) and NR2B were increased by 67% and 83%, …

Dna Binding Specificity Of Mu Transcription Factor C And Crystallization Of C : Dna Complex, Karthik Shanmugantham

Theses and Dissertations (ETD)

The lytic cycle of phage Mu is regulated by a transcriptional cascade consisting of early, middle and late transcription. The Mor protein is an activator of the middle promoter Pm and is encoded by the last gene of the early transcript. The C protein is an activator of the four late promoters Plys, PI, PP, and Pmom and is expressed from the middle transcript. Both Mor and C proteins bind an imperfect dyad-symmetry element just upstream and overlapping the –35 region of Pm and Plys respectively. The main aims of this study was, (1) To understand the binding specificity of …

Role Of Medial Prefrontal Cortical Group Ii Metabotropic Glutamate Receptor In The Development Of Cocaine Sensitization, Xiaohu Xie

Theses and Dissertations (ETD)

The current studies examined the role of medial prefrontal cortical (mPFC) group II metabotropic glutamate receptors (mGluR_2/3) in the development of cocaine sensitization. Initial studies demonstrated that intra-mPFC injection of the mGluR_2/3 receptor agonist, APDC, dose-dependently reduced acute behavioral response to cocaine (0.015-15 nmol/side with significant effects starting at 1.5nmol/side). The effects of APDC were prevented by intra-mPFC co-injections of an mGluR_2/3 antagonist, LY341495 (1.5 nmol/side). Repeated intra-mPFC APDC (1.5 nmol/side) injections also prevented the initiation of behavioral and neurochemical sensitization, which is defined as enhanced nucleus accumbens (NAc) dopamine response to cocaine. Once sensitization was …

Trabecular Calcium Phosphate Scaffolds For Bone Regeneration, Mark Ryan Appleford

Theses and Dissertations (ETD)

Bone tissue engineering represents a strategy for the repair or regeneration of damaged bone in the body. The science underlying this clinical therapy bridges the traditional fields of cell biology, materials science and mechanical engineering with the aim to identify how cells behave on physiologically relevant materials with natural mechanical stimuli. The objectives of this research were to develop and characterize calcium phosphate ceramic scaffolds matched to the local architecture of natural trabecular bone and to apply tissue engineering strategies for the study of cell behavior in both in vitro and in vivo models.The specific role of environment on cell …

Depth And Size Limits For The Visibility Of Veins Using The Veinviewer Imaging System, Soujanya Ganesh

Theses and Dissertations (ETD)

Administration of fluids or medication and blood draw procedures require the nurse or the phlebotomist to access the veins in patients at hospitals or phlebotomy centers. It is important to minimize the discomfort associated with sticking needles in the patient more than once and most often, necessary to find an appropriate vein within few minutes. However, problems involved in accessing veins in pediatric and obese patients make it very difficult to perform a successful stick in a short time. The VeinViewer Imaging System is an infrared imaging device that provides the nurses and phlebotomists a means for locating veins in …

Molecular Mechanism Of Tetraspanin Cd9 Mediated Cell Motility, Jayaprakash Kotha

Theses and Dissertations (ETD)

CD9, a member of the tetraspanin superfamily of proteins participates in the regulation of cell adhesive functions such as cell migration. The mechanisms underlying CD9 mediated cell migration are not known. In the current study, we investigated the molecular basis for the CD9 promoted cell migration. Our findings show that the phosphatidylinositol-3 kinase (PI-3K) inhibitors, wortamannin and LY294002 inhibited CD9 promoted cell motility in Chinese hamster ovary (CHO) cells. In contrast, inhibitors targeting protein kinase C or mitogen-activated protein kinase had no effect on CD9 driven CHO cell motility. Furthermore, inhibition of PI-3K activity in CHO cells by dominant/negative PI-3K …

Tyrosine Phosphorylation Of Villin: Effects On Actin Dynamics, Cell Morphology And Cell Migration, Alok Tomar

Theses and Dissertations (ETD)

Cell migration is a key aspect of many normal and abnormal biological processes, including embryonic development, defense against infections, wound healing, and tumor cell metastasis. In this study we demonstrate that an epithelial cell actin-binding protein, villin, plays a crucial role in the process of cell migration. Overexpression of villin in doxycyline-regulated HeLa Tet-off and MDCK Tet-off cells enhanced cell migration. We further demonstrate that tyrosine phosphorylation of villin by c-src is required for villin-induced cell migration. Previously, we identified four tyrosine phosphorylation sites in the amino-terminal domain of villin. I further identified six new sites in the carboxylterminal region …

Genetic Networks Modulating Retinal Injury, Felix Vazquez-Chona

Theses and Dissertations (ETD)

Many advances have and are being made with the advent of modern sciences. One area that remains resistant to significant advances is the recovery of the mammalian central nervous system (CNS) after injury. Considerable efforts were placed on understanding the cellular and biochemical changes occurring after injury and during wound healing. Aside from cataloging the changes that occur, little progress is being made in understanding the molecular cascades associated with the control of the healing process. The present series of studies define the global changes that occur after injury. They also define CNS repair mechanisms by identifying genetic networks that …

A Virtual Model Of The Human Cervical Spine For Physics-Based Simulation And Applications, Hyung Soo Ahn

Theses and Dissertations (ETD)

Utilizing recent advances in computer technology, Our Biomechanics Laboratory have made an effort to integrate computer animation and engineering analysis software into biomedical research, specifically towards simulation and animation of in vitro experimentation of the human cervical spine in the virtual world. The objectives of this study were to develop a virtual model of the human cervical spine for physics-based simulation and to apply the virtual model to studies of different surgical procedures and instrumentation.

A process for creating an accurate virtual model of the human cervical spine was developed. The model consisted of seven vertebrae (C2-T1) connected with soft …

Effect Of Background Synaptic Activity On Excitatory-Postsynaptic Potential-Spike Coupling, Veronika Zsiros

Theses and Dissertations (ETD)

Neurons receive large amount of synaptic inputs in vivo, which may impact the coupling between EPSPs and spikes. We mimicked the in vivo synaptic activity of the cell with the dynamic clamp system. We recorded from pyramidal cells in neocortical slices in vitro to investigate how timing and probability of spike generation in response to an EPSP is affected by background synaptic conductance under these conditions. We found that near threshold, background synaptic conductance improved the precision of spike timing by reducing the depolarization-related prolongation of the EPSP. In cells with ongoing spike activity and background synaptic conductances, an …

Advances In Dna Affinity Chromatography, William Himanshu S. Gadgil

Theses and Dissertations (ETD)

Different aspects of DNA affinity chromatography such as DNA complexity heparin elution, the Bi-column method and the oligonucluotide trapping method were studied. The complexity (length) of a DNA sequence attached to an affinity chromatography column affects column retention, and the purity of transcription factors obtained. T18: A18 tailed DNA affinity columns were better suited for purification of most of the transcription factors than either the discrete or concatemeric DNA affinity columns. A novel method using heparin for eluting transcription factors from DNA Sepharose columns was characterized. The amount of the lac repressor chimera which eluted from the column was shown …

Genetic Control Of Eye Development, A Case Study Focused On The Murine Mutation Belly Spot And Tail (Bst), Qing Tang

Theses and Dissertations (ETD)

Development of the eye is controlled by a network of genes, often conserved, that regulate the timing and location of cellular differentiation. One approach to understanding this network of genes and their interaction is to focus on mutations, spontaneous or induced, that predictably disrupt the proper function of such networks, and by examining the effect of such disruption on the function of other genes.

The Belly spot and tail (Bst) semi-dominant mutation, mapped to mouse Chromosome 16, leads to developmental defects of the eye, skeleton, and coat pigmentation. In the eye, the mutant phenotype is characterized by the presence of …

Characterizing Erythrocyte Motions In Flowing Blood, Markos Leggas

Theses and Dissertations (ETD)

Characterizing the probabilistic motions of cells is a prerequisite for the development of a general model of transport and surface deposition of white cells and platelets (WBC/P). These phenomena differ greatly when red blood cells (RBC) are present at normal levels, but follow convective diffusion in dilute suspensions. A critical need is to understand and characterize dispersion and diffusion as they apply to red cells in suspension flow. The dispersive motions of
0.5-micrometer beads and fluorescently labeled human RBC flowing in dilute (0.003%) and concentrated (25%) RBC suspensions, respectively, were characterized using fluorescence videomicroscopy methods, and times for individual tracer …

Developmental Expression Of Rat Target Of The Antiproliferative Antibody (Rtapa) Protein In The Brain, Clyde Dale Sullivan

Theses and Dissertations (ETD)

The present study defines the expression pattern of rTAPA (CD81) in the developing rat brain. rTAPA is a member of the tetramembrane spanning family of proteins, and like other members of this family, appears to be associated with the stabilization of cellular contacts. On immunoblots of the brain, rTAPA is present in higher levels than any other tissue examined: muscle, tendon, peripheral nerve, cartilage, liver, kidney, skin, and testicle. Immunohistochemical methods were used to define the distribution of rTAPA in the brain. This protein is expressed by ependyma, choroid plexus, astrocytes, and oligodendrocytes, and rTAPA is dramatically upregulated at the …

Job Accommodation In The Automobile Industry : Addressing The Problem Of Lateral Epicondylitis, Thanigaivel Ashwin Raj

Theses and Dissertations (ETD)

Cumulative trauma disorders are musculoskeletal problems such as carpal tunnel syndrome, rotator cuff tendinitis, and epicondylitis which can affect assembly line workers. The injuries are thought to result from repetitive motions performed under excessive loads in anomalous postures. The project aimed to design, build, install, and evaluate worksite accommodation at the Saturn plant for a worker with right lateral epicondylitis. The goal was to make her fully functional in her original team which required addressing the injurious aspects of the task that caused or aggravated her injury.

A process of observation, interview, and analysis identified “the door mount” operation on …

Regulation Of Luteinizing Hormone And Catecholamine Release, Benjamin Aaron Adler

Theses and Dissertations (ETD)

These studies tested the interrelated hypotheses that the ovarian hormones produce their positive feedback effects on luteinizing hormone (LH) secretion through activation of noradrenergic and adrenergic systems in specific hypothalamic regions. Furthermore, the ovarian hormones may alter the activity of opioid neuropeptide and Gamma-Aminobutyric Acid (GABA) systems to produce these alterations in catecholamine transmission and gonadotropin secretion. Radioimmunoassays were utilized to determine plasma LH and median eminence LHRH, and hypothalamic catecholamine concentrations were measured by radioenzymatic assay.

The first two studies tested whether epinephrine (EPI) synthesis inhibition blocks the accumulation of median eminence LHRH that precedes the ovarian hormone-induced LH …

Fatty Liver And Metabolism Of Xenobiotics In The Rat, Joyce D. Stone

Theses and Dissertations (ETD)

No abstract provided.

Characteristics Of The Recovery Of The Coenzyme A-Synthesizing Protein Complex From Saccharomyces Cerevisiae, Stanley Joseph Tarnowski Jr.

Theses and Dissertations (ETD)

A multienzyme complex contained in Bakers' yeast (Saccharomyces cerevisiae) which synthesizes CoA has been named the coenzyme A-synthesizing protein complex (CoA-SPC). The CoA-SPC has been shown to be insoluble in the crude Bakers' yeast cell lysate formed by exposing the yeast cell to ether and dry ice. Only after solubilization has this multienzyme complex been shown to catalyze the formation of bound dephospho-CoA utilizing the substrates adenosine triphosphate, D-pantothenic acid and L-cysteine. A low molecular weight component or components of the soluble fraction of the yeast cell and chloride ion appears to be responsible for the solubilization of CoA-SPC. This …

The Synthesis Of Active Site Directed Inhibitors For The Lac Permease Of Escherichia Coli, Mahmoud Ahmed

Theses and Dissertations (ETD)

No abstract provided.

Evidence For Bone Marrow Cell Attrition As A Mechanism For Granulocyte Regulation In The Canine, Vincent Dee Smith

Theses and Dissertations (ETD)

No abstract provided.

The Purification, Properties And Subunit Structure Of Glycerol Dehydrogenase, Michael James Barrett

Theses and Dissertations (ETD)

The inducible, NAD-linked glycerol dehydrogenase (E.C. 1.1.1.6) of a guanine requiring mutant of A. aerogenes has been purified to homogeneity. The molecular weight of the pure enzyme was found to be 3.4 x 10⁵ daltons. The sedimentation coefficient of the enzyme was 10.7 x 10^-13 sec.^-1. The diffusion constant was 3.07 x 10^-7 cm²/sec.

The partial specific volume calculated from the amino acid composition was 0.72 ml/g. The following kinetic parameters were determined; K_m glycerol, 2.4 x 10^-3 m, K_m NAD, 2.8 x 10^-4 M, K_m dihydroxyacetone, 5.1 …