Biomedical Engineering and Bioengineering Commons^™

Peroxisome Proliferator-Activated Receptor Alpha: Insight Into The Structure, Function And Energy Homeostasis, Dhawal P. Oswal

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Peroxisome proliferator-activated receptor alpha (PPAR alpha) belongs to the family of ligand-activated nuclear transcription factors and serves as a lipid sensor to regulate nutrient metabolism and energy homeostasis. The transcriptional activity of PPAR alpha is thought to be regulated by the binding of exogenous ligands (example, fenofibrate, TriCor), as well as endogenous ligands including fatty acids and their derivatives. Although long-chain fatty acids (LCFA) and their thioesters (long-chain fatty acyl-CoA; LCFA-CoA) have been shown to activate PPAR alpha of several species, the true identity of high-affinity endogenous ligands for human PPAR alpha (hPPAR alpha) has been more elusive. This two …

Elucidating A Role Of Btf And Trap150 In Pre-Mrna Processing And Cell Cycle Progression, Sapna N. Varia

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Transcription of protein-coding genes is coordinated with pre-mRNA processing as well as mRNP assembly and nuclear export in mammalian cells. In this dissertation, I examined the functions of two homologous non-classical serine-arginine-rich (SR) proteins, Btf (BCLAF1) and TRAP150 in these steps of gene regulation. Since Btf and TRAP150 share 39% sequence identity and 66% sequence similarity, I also examined whether Btf and TRAP150 have overlapping or distinct functions in pre-mRNA processing. Using two different reporter loci, I showed in-situ recruitment of Btf and TRAP150 at reporter transcription sites, and I identified both Btf and TRAP150 being associated with a core …

Differential Regulation Of The Hippocampal Taurine Transporter Protein In Rat Brain: Mechanisms Contributing To Neuronal Volume Regulation, Amanda Noelle Freeman

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Background. In osmotic edema, net efflux of taurine from neurons and accumulation by astrocytes contributes to neuronal volume regulation and astrocytic swelling. Taurine is accumulated in both cell types by a sodium- and chloride-dependent 72-75 kDa protein transporter, TauT. TauT functional activity decreases in osmotically swollen neurons but is unaltered in swollen astrocytes, in vitro. This swelling-induced downregulation of neuronal TauT activity is blocked with the tyrosine kinase (TK) inhibitor, genistein. In contrast, PKC activation has no effect on neuronal TauT, but inhibits astrocytic TauT. Thus, we hypothesize that during osmotic swelling, neuronal TauT activity is regulated by a TK …

Reactive Oxygen Modulates B Lymphocyte Function Via The Nfκb/Rel Pathway, Eric J. Romer

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Reactive Oxygen Intermediates (ROI) can significantly affect B Lymphocyte function, but the effects on key signaling pathways and gene expression in activated and non-activated B lymphocytes are largely undefined. This study demonstrates a concentration dependent effect of exogenous hydrogen peroxide on the transcriptional regulation of a 3' regulatory region of the Immunoglobulin heavy chain gene (3'IghRR). Specifically, low μM hydrogen peroxide induces an enhancing effect while higher μM hydrogen peroxide (greater than or equal to 100 μM) is suppressive. The enhancing effects of hydrogen peroxide on 3'IghRR activity are dependent on the NFκB/Rel pathway, and appear to be most prominent …

A Comprehensive Tool And Analytical Pathway For Differential Molecular Profiling And Biomarker Discovery, Claude Curtis Grigsby

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The key requirements to any empirically based study are to: (1) accurately measure and then compare the collected results in determining the result of the hypothesis being tested; and (2) collect a sample representative of the entities being studied. To demonstrate that an informatics tool can be designed that provides spectral registration, spectral and chromatographic alignment, visualization, and comparative analysis for data generated from multiple analytical platforms, e.g., LC-MS and GC-MS, the results and data analysis of five unique sets of experiments using a suite of novel informatics tools are presented. Comprehensive and reproducible sample collection techniques were developed concomitantly …

Simulating Hemodynamics In In Vitro Culture Models: Implications On Nano-Biointeractions, Monita Sharma

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Gold nanoparticles (Au-NPs) have demonstrated great potential in the development of a variety of tools with applications ranging from biomedical to military fields. Consequently, there is increasing concern regarding the toxic potential of these nanomaterials. Biodistribution studies demonstrate clearance of Au-NPs from peripheral circulation and bulk localization primarily in the liver and spleen post- intravenous administration. Deposition of Au-NPs in spleen suggests the potential for direct exposure of immune cells to these foreign materials under relatively static conditions. Although much less, due to the Blood Brain Barrier (BBB), Au-NPs appear to also deposit in the brain, suggesting that the resident …

The Molecular Genetics Learning Progressions: Revisions And Refinements Based On Empirical Testing In Three 10th Grade Classrooms, Amber Nicole Todd

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In the past few decades, there has been a large push for increasing scientific literacy (AAAS, 1989; AAAS, 1993; Achieve, 2013; NRC, 1996; NRC, 2012), especially in areas that are rapidly advancing, like molecular genetics. Much research has been done on student understandings of molecular genetics and the consensus is that the concepts are difficult both to learn and teach (Fisher, 1992; Horwitz, 1996; Kindfield, 1992; Lewis & Kattmann, 2004; Marbach-Ad & Stavy, 2000; Stewart et al., 2005; Venville & Treagust, 1998; etc.). Two learning progressions in molecular genetics have been produced (Duncan et al., 2009; Roseman et al. 2006), …

New Insights Into The Spinal Recurrent Inhibitory Pathway Normally And After Motoneuron Regeneration, Ahmed Zayed Obeidat

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Despite more than seven decades of intensive research, uncertainty is the hallmark of spinal recurrent inhibition. The simplest possible structure that is formed between the a-motoneuron and its inhibitory interneurons has been the subject of long lasting scientific debate. To date, there is no consensus on the functional significance of this circuit. Even the simplest assumption of a negative feedback loop does not hold true. The current work used the technique of in vivo intracellular recording from the adult rat a-motoneurons to study the normal function and the plasticity after nerve injury and regeneration of this simple, yet intricate spinal …

Applications Of Capillary Electrophoresis For Studying Serum Albumin Enantioselection Of D,L-Tryptophan Analogs, Jelynn A. Stinson

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The pharmacokinetic difference between drug enantiomers is the impetus for developing analytical techniques to assess enantiomeric purity. Capillary electrophoresis (CE) is an analytical technique that is used for characterizing drug-protein binding. The pitfall to using CE for drug-protein binding studies is protein chiral selectors tend to adsorb onto capillary walls and cause changes in electroosmotic flow that lead to decreased enantioselection and migration time irreproducibility between consecutive injections. The experimental parameters for minimizing the adverse effects of protein adsorption are not clear from the literature.

Rinsing protocols to improve enantioselection and migration time repeatability were developed using the tryptophan-bovine serum …

Regulation Of The Transcription And Subcellular Localization Of The Tumor Suppressor Pten By Δnp63Α, Mary Kathryn Leonard

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Non-melanoma skin cancers (NMSCs) are the most common form of cancer in the United States with an estimated 3.5 million new cases each year. Surgical excision is the main treatment for NMSC, but leaves the potential for disfiguring scars and does not fully reduce the risk of recurrence since the surrounding tissue is also sun damaged and may contain tumor-promoting mutations. By understanding the molecular etiology of NMSC we may be able to expand treatment options to more than just resection. Normal epidermal development is dependent upon the expression of the transcription factor p63. Amplification of the ΔNp63α isoform is …

The Role Of Amp-Activated Protein Kinase (Ampk) In Hypoxic Chemotransduction By The Carotid Body, Heidi Lynn Jordan

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The carotid bodies are small sensory organs located along the bifurcation of the carotid arteries. They detect changes in blood gases and relay this information to the brain to allow for initiation of appropriate respiratory and cardiovascular responses. A decrease in oxygen (hypoxia) sensed by the carotid body results in an increase in firing of the carotid sinus nerve and ultimately a change in one's breathing pattern. An inability to respond to an acute hypoxic (low oxygen) episode via increased ventilation may result in death or lead to pathological or chronic conditions such as stroke and hypertension (Prabhakar et.al., 2005). …

The Role Of Angiotensin Converting Enzyme (Ace) 2 In A Murine Model Of Insulin Resistance And Albuminuria, Nathan Michael Weir

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Insulin resistance and kidney disease are intimately linked and both independently tied to dysregulation of the renin angiotensin system (RAS). The purpose of this research was to better investigate Angiotensin Converting Enzyme (ACE) 2 as a possible motif in the pathophysiology of these two disease processes. The project was divided into two parts. Part 1 investigated ACE2 KO mice as a model of albuminuria. Part 2 investigated how the lack of ACE2 enzyme affected glucose homeostasis and subsequent albuminuria.

Part 1: The Role of ACE2 in the Progression of Albuminuria. To determine if global loss of ACE2 leads to spontaneous …

'Omic' Evaluation Of The Region Specific Changes Induced By Non-Cholinergic Diisopropylfluorophosphate (Dfp) Exposure In Fischer 344 Rat Brain, Deirdre A. Mahle

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Organophosphorous compounds (OPs) are a class of serine esterase inhibitors that have widespread application as pesticides, veterinary pharmaceuticals and chemical warfare agents. Environmental contamination is ubiquitous. The threat of exposure is a concern for both military and civilian populations. Acute inhibition of acetylcholinesterase by OPs triggers a cholinergic crisis that results in muscle flaccidity, paralysis, convulsions and death. At low doses OPs can alter neuronal differentiation, cell signaling, behavior and cognition through unknown mechanisms. An imbalance of reactive oxygen species may be implicated in the adverse effects of OPs. An integrated approach using both metabolomic and transcriptomic techniques was used …

Limitations Of Functional Recovery Of Stretch Reflex Circuitry After Peripheral Nerve Regeneration, Gabrielle Marie Horstman

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Peripheral nerve regeneration fails to restore complete normal function after surgical repair of severed nerves, and this failure has primarily been attributed to errors in connecting with peripheral targets. However, recent evidence suggests that central deficits remain even after peripheral target reinnervation is largely successful. It has long been established that regeneration fails to restore the stretch reflex despite observation that many of the neural components are intact. Regenerated Ia afferents are largely successful in reinnervating muscle spindles, are capable of encoding stretch, and elicit EPSPs in homonymous motoneurons, while regenerated motor pools are capable of responding to uninjured sources …

The Role Of Ca2+ In Central Respiratory Control Neurons Of The Locus Coeruleus: Development Of The Chemosensitive Brake, Ann Nicole Imber

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Chemosensitive LC neurons increase their firing rate in response to increased CO₂ (hypercapnia) in part via inhibition of K⁺ channels. This increase gets smaller during the first two postnatal weeks (neonatal rats aged P3-P16). Alterations of this "accelerating" pathway may account for the developmental changes in the magnitude of the chemosensitive response in LC neurons. Alternatively, Ca²⁺ and Ca²⁺ channels may play a role in the response to hypercapnia, but little is known about the role of Ca²⁺ in central chemosensitivity. Whole cell patch clamp and fluorescence imaging microscopy were used to study a different …

A Mechanism-Based Model To Describe Gabaa Receptor Trafficking And Benzodiazepine Pharmacoresistance During Status Epilepticus, Elaine Alice Merrill

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Status epilepticus (SE) is a perplexing pathology involving a sudden and long disruption of the brain's normal electrical activity. The study of relevant cellular processes has been useful in identifying therapeutic targets. As a result, many novel drugs are being studied which target receptor systems involved in neuronal membrane excitability. Yet, the standard treatment for SE remains benzodiazepines (BZs), a class of GABAA agonist drugs. Unfortunately, the targeted receptors undergo a desensitization mechanism via enhanced endocytosis (receptor trafficking), leading to rapidly reduced BZ efficacy (pharmacoresistance) within minutes of seizure onset. A comprehensive understanding of the complex interplay between the anticonvulsant's …

Regulation Of The Dna Unwinding Element Binding Protein Due-B In The Cell, Yanzhe Gao

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Eukaryotic cells have evolved tightly controlled processes that make sure the entire genome gets replicated accurately, once per cell cycle. This tight control is fulfilled by degrading replication proteins after their function is carried out, changing their cellular location or by post-translational modification of replication factors to regulate their function. Phosphorylation events carried out by CDKs (cyclin dependent kinases) and DDKs (Dbf4 dependent kinases) play crucial roles in this regulation.

The DNA unwinding element binding protein (DUE-B) is an essential replication protein that binds to the human c-myc DNA replication origin. In this study, I find that DUE-B is also …

Development Of A Direct-Write System For Ceramic Colloidal Inks, Jorge Mireles^, Miguel Verdecchia, David Espalin, Geoffrey Saupe, Noe Vargas, Frank Medina, Ryan Wicker*

COURI Symposium Abstracts, Summer 2011

No abstract provided.

Analysis Of Sealing Methods For Fdm-Fabricated Parts, Arturo Adame^, Jorge Mireles, David Espalin, Frank Medina, Rob Winker, Terry Hoppe, Bob Zinniel, Ryan Wicker*

COURI Symposium Abstracts, Summer 2011

No abstract provided.

Quantitative Computed-Tomography Based Bone-Strength Indicators For The Identification Of Low Bone-Strength Individuals In A Clinical Environment, Bino Abel Varghese

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The aim of the current study was to develop quantitative computed-tomography (QCT)-based bone-strength indicators that highly correlate with finite-element (FE)-based strength. We perform a combined numerical-experimental study, comparing FE-predicted surface strains with strain gauge measurements, to validate the FE models of 36 long bones (humerus, radius, femur and tibia) under three-point bending and torsion. The FE models were constructed from trans-axial volumetric CT scans, and the segmented bone images were corrected for partial-volume effects. The material properties (Young's modulus for cortex, density-modulus relationship for trabecular bone and Poisson's ratio) were calibrated by minimizing the error between experiments and simulations among …

Aberrant Dna Replication At An Ectopic Chromosomal Site In Human Cells, Xiaomi Chen

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Aberrant DNA replication, including over-replication or under-replication may lead to life-threatening mutation or even cause human diseases. This thesis focused on three issues related to abnormal DNA replication in human chromosomes including: I) to define the function of DNA unwinding element (DUE) and DNA unwinding element-binding protein (DUE-B) to maintain an active c-myc replicator; II) to determine the role of trans-acting factors in defining a replication origin on human chromosomes; III) to investigate the mechanism by which hairpins affect DNA replication and instability of (CTG)n•(CAG)n trinucleotide repeat tracts in human cells.

Our laboratory previously demonstrated that both DUE and DUE-B, …

V1-Derived Renshaw Cells And Ia Inhibitory Interneurons Differentiate Early During Development, Ana Benito González

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Locomotor development is dependent on the maturation of spinal cord circuits controlling motor output, but little is known about the development of the spinal interneurons that control motoneuron activity. This study focused on the development of Renshaw cells (RCs) and Ia inhibitory interneurons (IaINs), which mediate recurrent and reciprocal inhibition, respectively, two basic inhibitory circuits for motorneuron control. Both interneurons originate from the same progenitor pool (p1) giving rise to ventral spinal embryonic interneurons denominated V1. V1-derived interneurons (V1-INs) establish local inhibitory connections with ipsilateral motoneurons and express the transcription factor engrailed-1. This characteristic permitted the generation of transgenic mice …

Impact Of Insulin Resistance On Behavioral And Neurochemical Deficits In Db/Db Mice, Ajaykumar Narayan Sharma

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There is a high comorbidity of type-2 diabetes and neuropsychiatric disorders. However, there is paucity of preclinical research to study this phenomenon. The validity of the db/db mouse as an animal model to study type-2 diabetes and related macrovascular and microvascular complications is well established. The first part of this dissertation was designed to investigate comprehensively the db/db mouse behavior as preclinical evidence of type-2 diabetes related major neurobehavioral complications. Juvenile (5-6 weeks) and adult (10-11 weeks) db/db mice were screened for behavioral depression in forced swim test (FST), psychosis-like symptoms using pre-pulse inhibition (PPI) test, anxiety behavior employing elevated …

The Development Of Silver Nanoparticles As Antiviral Agents, John Christopher Trefry

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Silver nanoparticles (AgNPs) have received tremendous attention for their antimicrobial properties; however, many gaps in knowledge exist. To address these issues, three research objectives were examined. The first objective hypothesized AgNPs can be size selected and concentrated via tangential flow ultrafiltration. The second objective hypothesized a high-throughput method could be developed to screen nanoparticle antiviral-activity and cytotoxicity simultaneously. The third objective hypothesized AgNPs inhibit viruses by preventing viral entry.

For objective one, a tangential flow ultrafiltration scheme was tested on AgNPs synthesized via the Creighton Colloid method. AgNPs were analyzed via transmission electron microscopy. In objective two, an HIV-1 vector …

Son Is Essential For Nuclear Speckle Organization, Cell Cycle Progression And Pre-Mrna Splicing, Alok S. Sharma

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Nuclear speckles provide important spatial organization and dynamic regulation for pre-mRNA processing factors in mammalian cells. While the nuclear speckle proteome is complex, little is known at the molecular level about how these factors are organized into nuclear speckles or how alterations in the organization of these factors impacts gene expression. We have discovered a new function for a large (2564 amino acid) nuclear speckle protein called Son in maintaining the organization of pre-mRNA processing factors in nuclear speckles. Depletion of Son by RNAi causes snRNP and serine-arginine rich (SR protein) splicing factors to undergo dramatic disorganization into doughnut-shaped nuclear …

A Computational Tool For Biomolecular Structure Analysis Based On Chemical And Enzymatic Modification Of Native Proteins, Deacon John Sweeney

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Chemical and enzymatic modification of proteins is a well-established treatment technique for probing the conformational properties of these macromolecules. Investigators have recently extended the approach to probe many sites on a protein's structure in parallel manner, such that conformational properties of a target protein can be inferred. The modern approach uses mass spectrometry to quantify reactant loss and product formation. Rigorous analysis is challenging due to the high volume of mass spectrometric data that must be processed and interpreted.

An extensively interactive software suite has been developed to assist various aspects of the analytical protocol. The software offers a variety …

The Molecular Basis Of The Interaction Between The Coxsackievirus And Adenovirus Receptor (Car) And Magi-1, Abimbola Olayinka Kolawole

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A major factor in virus entry into cells is localization and abundance of the primary receptor. The Coxsackievirus and adenovirus receptor (CAR) is the primary receptor for group B coxsackievirus and many serotypes of adenovirus. In most epithelia, a seven exon isoform of CAR (CAR^Ex7) is exclusively localized at the basolateral surface where it behaves as a homophilic adhesion protein and is inaccessible for viral infection. However, in well-differentiated human airway epithelia, we recently discovered an alternatively spliced, low abundance isoform of CAR (CAR^Ex8) that is apically localized where it may initiate apical viral infection. The …

Understanding The Molecular Dynamics Of Ypel3 And Fhit Gene Expression, Kevin Daniel Kelley

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A comprehensive understanding of the molecular signaling pathways that regulate cell growth and proliferation is essential in the realization of new therapeutic options to facilitate early detection and eradication of malignancy. Understanding the transcriptional regulation of the YPEL3 and FHIT genes forms the basis of this dissertation. YPEL3, or Yippee-like 3, is a newly identified p53 target gene that inhibits tumor cell growth and is thus itself, a novel tumor suppressor gene. FHIT, or Fragile histidine triad, is a well known tumor suppressor gene and is regulated at the transcriptional level by another growth inhibitory protein, FOXO3a, a Forkhead box …

Extent And Effects Of Selection To Reduce Synthetic Cost Of Highly Expressed Proteins, Esley Marvin Heizer Jr

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Organisms that preferentially utilize less biosynthetically expensive amino acids in highly expressed genes exhibit metabolic efficiency. Exploration of this phenomenon has been limited to six prokaryotes.

I present a large scale analysis of metabolic efficiency in prokaryotic organisms and analysis of two eukaryotes (Saccharomyces cerevisiae and humans). Examination of 73 bacteria reveals the presence of metabolic efficiency in 66 organisms. The average correlation between amino acid biosynthetic cost and CAI scores in these organisms is -0.21. The seven organisms that did not exhibit metabolic efficiency are all Lactobacilli and highly auxotrophic. Saccharomyces cerevisiae exhibits significant trends between average amino acid …

Induction Of P53 Dependent Cellular Senescence Through Hdmx Inhibition Or Ypel3 Expression, Kelly Lynn Robbins Miller

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Mutations in p53 that compromise its function have been reported in approximately half of all human cancers (Vousden et al., 2002). The other half of human tumors that retain wild-type p53 have a dysfunctional p53 pathway through other mechanisms (Wade et al., 2009). Activation of p53 leads to cell cycle arrest, DNA repair, apoptosis and senescence, however, the pathway leading to cellular senescence is the focus of this study. Cellular senescence is a process leading to irreversible arrest of cell division. Under normal physiologic conditions, the activity of p53 is kept in check by its negative regulators, Mdm2 and MdmX. …