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Environmental Responses Of Two-Component Systems In Streptococcus Sanguinis, Jenishkumar Patel

Theses and Dissertations

The gram-positive bacterium Streptococcus sanguinis is a member of human indigenous oral microbialflora and has long been recognized as a key player in the bacterial colonization of the mouth. S. sanguinis is also the most common viridians streptococcal species implicated in infective endocarditis. Although many studies have focused on two-component systems in closely related Streptococcus species such as S. mutans, S. pneumoniae and S. gordonii; the mechanism of the response regulator in S. sanguinis is still unknown. The ability of S. sanguinis to adapt and thrive in hostile environments suggests this bacterium is capable of sensing and responding to various …

Volumetric Growth Model Of Human Medulloblastoma In The Nude Mouse Cerebellum, Thomas Gavigan

Theses and Dissertations

Medulloblastoma is the most common brain tumor in children, accounting for 10-20% of primary central nervous system (CNS) neoplasms and approximately 40% of all posterior fossa tumors. It is a highly invasive embryonal neuroepithelial tumor that typically arises in the cerebellar vermis and has a tendency to disseminate throughout the CNS early in its course. The molecular mechanisms of the disease largely remain uncharacterized, as the clinical treatment is still associated with mortality and severe side effects. The development of a clinically relevant in vivo model is important not only to further understand the disease but also to provide a …

The Role Of Nitric Oxide, Acetylcholine, And Vasoactive Intestinal Peptide On Skin Blood Flow During In-Vivo Electrical Field Stimulation, Robert S. Thiebaud

Theses and Dissertations

The purpose of this study was to characterize a novel technique to study neurogenic control of cutaneous vasodilation. We monitored skin blood flow (SkBF) during in-vivo electrical stimulation (e-stim) intended to activate cutaneous nerves and used intradermal microdialysis to deliver receptor antagonists to characterize their contribution to cutaneous vasodilation. We examined the role of acetylcholine receptors (RACh), nitric oxide (NO), and vasoactive intestinal peptide receptors (RVIP) on the cutaneous vasodilation induced by e-stim in the absence of the sympathetic adrenergic nervous system. Six men and three women participated in the study. Three intradermal microdialysis probes were placed in the skin …

Factors Affecting Gingival Excess, Altered Passive Eruption And Recession In The Mandibular Anterior And Premolar Sites, William Bohlen

Theses and Dissertations

Abstract FACTORS AFFECTING GINGIVAL EXCESS, ALTERED PASSIVE ERUPTION AND RECESSION IN THE MANDIBULAR ANTERIOR AND PREMOLAR SITES By William F Bohlen, D.M.D. A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University. Virginia Commonwealth University, 2010 Major Director: Thomas Waldrop, DDS, MS Program director, Department of Periodontics, Virginia Commonwealth University AIM: The aim of this study was to determine the factors affecting gingival excess, altered passive eruption and recession. METHODS: 100 subjects were examined clinically and models of their mandible were fabricated. Demographic, periodontal and cast measurements were …

Smokers' Responses To Fearful And Disgust-Eliciting Anti-Smoking Media, Mark C. Goetz

Theses and Dissertations

The purpose of this study was to build upon Wakefield and colleagues and Vogeltanz-Holm and colleagues hypotheses that anti-smoking ads are effective by means of eliciting negative emotional states, particularly disgust. In this study, we compared two sets of ads: those high in fear and disgust and those high in only fear. We hypothesized that subjective and physiological responses to ads high in fear and have a disgust component would be greater than for the fear-only ads. We also predicted that the ads high in disgust would have higher rates of recall and engagement. Last, we predicted that participants viewing …

The Role Of Social Support On Risk Factors And Frequency Of Non-Suicidal Self-Injury, Erica R. Hoff

Theses and Dissertations

The primary purpose of the current study was to examine the role of social support as a potential protective factor of non-suicidal self-injury (NSSI). Specifically, the study hypothesized that social support would moderate (decrease) the power of the relationship between NSSI risk factors and NSSI frequency. The four risk factors of interest were borderline personality disorder (BPD) traits, an invalidating family environment, depression, and anxiety. Data was collected via self-report questionnaires from a sample of 233 individuals currently enrolled as undergraduates at the University of North Dakota. Results indicated individuals with a history of one or more acts of NSSI …

Proficient Dantrolene Administration, Erik Watson,

Theses and Dissertations

Malignant hyperthermia (MH) is a rare, life-threatening, acute hypermetobolic condition that is elicited by exposure to specific drugs used during general anesthesia. These drugs include the volatile anesthetics and the depolarizing muscle blocking antagonist. The morbidities and mortality associated with MH is significant enough that each and every anesthetic provider guards against it

Treatment and management of MH is laborious and extensive. The Malignant Hyperthermia Association of the United States (MHAUS) provides the practitioner with approp1iate treatment measures through established protocol. Dantrolene is the mainstay treatment for MH. However, the management of secondary pathologies that follow in the MH crisis …

Perceived Levels Of Empowerment In Parish Nursing, Jean C. Bokinskie

Theses and Dissertations

Parish nursing is a community-based subspecialty practice of nursing. The parish nurse (PN) melds spiritual care with nursing practice to wholistically address the needs of parishioners and faith communities. PNs work with other health care providers and organizations, as well as lay and professional church leaders to successfully develop, organize, and lead health promoting and spiritually healing activities. Empowerment of PNs is necessary to achieve positive outcomes of PN directed initiatives. Empowerment occurs through supportive and nurturing environments, as well as access to resources, information and power. However, multiple professional demands, interpersonal conflicts, and lack of adequate resources have created …

Assessing Economic And Hrql Burden Of Food Allergy And Anaphylaxis In The U.S., Dipen Patel

Theses and Dissertations

Background: Food allergy, an abnormal immunologic response to food protein, has an estimated prevalence of 6% in young children and 3.7% in adults in the U.S. The only proven therapy for food allergy is strict elimination of the offending allergens. As a result, caregivers and patients could experience constant anxiety and stress that affects their quality of life. Additionally, food allergy can lead to significant economic impact on the health care system, since severe reactions often lead to ED visits and hospitalizations. Objectives: The first major objective was to determine the economic burden of Food Allergy and Anaphylaxis (FAA) patients …

Contribution Of Nuceliec Acids On The Structure Of Recombinant Hepadnavirus Core Antigens, Maimuna Bruce

Theses and Dissertations

The Hepatitis B core antigen (HBcAg) has been proposed to be an ideal candidate for use as an adjuvant due to its immunogenicity, and tolerance to manipulations such as insertions of epitopes or covalent attachment of ligands. HBcAg is a complex macromolecule containing protein and nucleic acid. We investigated the effect of the removal and reconstitution of nucleic acids upon its structure. It’s been shown that the RNA content of hepadnavirus core antigens can be reduced significantly, but not be completely removed. Following removal of some of the RNA, antigens retain the ability to bind added nucleic acids, in particular, …

Function And Regulation Of Matrix Metalloproteinase-1 In Glioblastoma Multiforme, Monika Anand

Theses and Dissertations

Glioblastoma Multiforme (GBM) is an aggressive and fatal cancer of the brain. It is characterized with augmented morbidity and elusion to therapies due in part to the incessant infiltration and spread of tumor cells in normal brain. We investigated the function of Matrix metalloproteinase-1, an important enzyme noted to be responsible for invasion in other cancers, in GBM and its regulation by epidermal growth factor receptor (EGFR) signaling. Previous studies from our laboratory demonstrated elevated levels of MMP-1 in GBM. Further studies indicated the involvement of MMP-1 in GBM invasion. The GBM cell lines T98G, U251MG and U87MG were used …

Characterization And Crystallization Of The Mycobacterium Tuberculosis Trmd, Zohal Hamidi

Theses and Dissertations

One third of the world’s population is affected by Tuberculosis (TB), a disease caused by infection with Mycobacterium tuberculosis (MtB). The emergence of multidrug-resistant MtB makes this disease a major public health concern. New agents are needed to treat TB infections in a manner that circumvents existing pathways of resistance. One strategy is to target the organism at the translational level by inhibiting vital modifications of RNA. One gene responsible for these modifications is the tRNA (guanosine-1)-methyltransferase, trmD, which has been shown to be essential in several bacteria. The eukaryotic and bacterial m1G methyltransferases are structurally dissimilar, making this enzyme …

The Impact Of Adolescent Nicotine Exposure On Drug Dependence In Adulthood, Mai Alajaji

Theses and Dissertations

Nicotine is one of the first and most commonly abused drugs in adolescence. According to The Center for Disease Control, every day more than 6000 adolescents try their first cigarette and over 3000 of them become daily smokers. Smoking among adolescents is a strong predictor of future drug abuse and dependence in adulthood. A number of studies has suggests that adolescents pre-exposed to nicotine may suffer permanent disruption of the brain’s reward systems through changes in dopamine receptor function. We hypothesize that nicotine exposure during adolescence causes long lasting neurobiological alterations that increase the likelihood of cocaine use in adulthood. …

Role Of Xrcc3 In Acquisition And Maintenance Of Invasiveness Through Extracellular Matrix In Breast Cancer Progression, Siddharth Saini

Theses and Dissertations

Acquisition of invasiveness through extracellular matrix is a crucial characteristic of transition to malignancy in the breast. It was previously shown that Polo-like kinase 1 (PLK-1), a mitotic kinase and genome stability regulator, is involved in acquisition of invasiveness in a breast cell model (HMT-3522 cell line) of pre-invasive to invasive transition. This and other data led to the suggestion that a new class of genes called GISEM for Genome Instability and Extracellular Matrix Invasiveness may exist. Previous lab data show that XRCC3 is found downregulated in progression from preinvasive to invasive phenotype. This led to the hypothesis that XRCC3 …

Interactions Of Burkholderia Pseudomallei And Acanthamoeba Castellanii And Their Effects On Virulence In Human Monocytes, Emily Ann Moore

Theses and Dissertations

Burkholderia pseudomallei, the etiological agent of melioidosis, is a saprophytic bacterium existing endemically in the water and soil of SE Asia and Northern Australia. This organism has shown the ability to remain dormant in its host for decades. B. thailandensis is a closely related non-pathogenic near neighbor that is also found in these soils. It has been suggested that free-living amoeba could be natural reservoirs for these organisms. The interactions of Burkholderia species and Acanthamoeba castellanii, a species of free-living amoeba, were studied to better understand the natural ecology of these organisms and to determine the effects amoeba …

Ribosomal Synthesis Of N-Methylated Peptides, Sara Ahadi

Theses and Dissertations

Natural peptide products isolated from various organisms often contain N-methylated backbones. Such a modification of backbone of the peptide changes its conformational rigidity. This modification improves the biological properties of the peptide, such as improved target affinity, proteolytic stability or membrane permeability. Therefore synthesis of N-methylated peptide libraries is valuable in screening for drug-like peptides suitable for therapeutic uses. Protein synthesis using recombinant elements (PURE) and Flexizyme were used in order to reassign specific codons to N-methyl amino acids. mRNA-dependent translation system enable us to make our desired peptides with N-methyl amino acids. This technology is a convenient tool for …

Effect Of Mechanical Stimulation On Mesenchymal Stem Cell Seeded Cartilage Constructs, Karin Wartella

Theses and Dissertations

Cartilage tissue engineered constructs using mesenchymal stem cells were stimulated with 3 different stimulation algorithms to achieve characteristics mimicking the superficial tangential zone of articular cartilage. The stimulation algorithm of both compression and tension without an offset had the best properties out of all the evaluated groups.

Evolutionary Relationships In Afro-Malagasy Schefflera (Araliaceae) Based On Nuclear And Plastid Markers, Morgan Gostel

Theses and Dissertations

The genus Schefflera is the largest in Araliaceae, with approximately 900 species. Recent studies have shown that Schefflera is polyphyletic and represents no fewer than five distinct clades, each corresponding to a specific geographic region including Asia, continental Africa and Madagascar, Melanesia, the Neotropics, and a small clade distributed throughout several islands in the insular Pacific Ocean. The Afro-Malagasy clade contains nearly 50 species distributed throughout tropical, sub-Saharan Africa, Madagascar, the Comoros, and the Seychelles islands. Previous studies have suggested that this group is monophyletic, identifying two smaller subclades within Afro-Malagasy Schefflera corresponding roughly to informal groups identified as “Meiopanax” …

Moral Identification: An Alternative Approach To Framing Second-Generation Immigrants' Ethnic Identity Ambivalence, Benjamin R. Brady

Theses and Dissertations

Contemporary sociological research on second-generation immigrants living in the United States is lined with questions of ethnic inclusion and transnational participation. Many scholars are interested in how the children of immigrants relate to their parents' ethnic identity while being raised in a new land. Noting that the majority of scholars in this field approach ethnic identity within a social constructionist perspective, in this study I explore the ways that identity ambivalence and ethnic belonging are framed. Specifically, I critically question the ways that an ethnic identity is assumed to be valued and asserted in a constructionist model. After presenting a …

The Effects Of Hydrology And Vegetation On Microbial Community Structure And Soil Function In The Sediments Of Freshwater Wetlands, Christine Prasse

Theses and Dissertations

In wetland soils, hydrology is considered to be one of the primary factors shaping wetland function and microbial community structure, but plant-soil interactions are also important mechanisms affecting microbial nutrient transformations. The research presented here considered the interactive effect to describe how hydrology and the presence of plants alter the soil profile, the development of the bacterial community, and their associated functions. To achieve this goal, plots were established in three hydrologically-distinct regimes (Wet, Intermediate, and Dry) within a non-tidal freshwater wetland along the James River (Charles City County, Virginia). Inside each main plot, ten subplots were cleared of all …

The Relationship Among Maternal Infant Bonding, Spirituality, And Maternal Perception Of Childbirth Experience, Linda Bennington

Theses and Dissertations

The beginning of life is an intense experience for both mother and baby and sets the foundation for future interactions. Researchers have theorized that maternal infant bonding begins prenatally and continues on through the postnatal period. Mṻller (1996) examined that process to determine if prenatal bonding was related to postnatal bonding and discovered that there was only a modest correlation between the two. This led to speculation as to what variables, besides prenatal bonding, could influence postnatal bonding. Klaus & Kennell (1976) noted the detrimental effects of a lack of bonding in terms of abuse and attachment disorders and emphasized …

Effects Of Alternative Prey As A Buffer To Predation Of Channel Catfish (Ictalurus Punctatus) By Largemouth Bass (Micropterus Salmoides), Shelley Nellis

Theses and Dissertations

Channel catfish have pectoral spines that lock to defend against gape-limited predators such as largemouth bass. Previous work indicated that spines increase survival of channel catfish exposed to bass but did not determine whether bass avoid catfish if less dangerous species are available. We presented bass with channel catfish and two alternatives, bluegill and goldfish, and compared order of ingestion, ingestion time, percent of successful strikes, and time spent chasing each prey species. We also presented the three species in a jar study that standardized position in the water column as well as in a net-pen study. The order of …

Insights Into The Catalytic Mechanism Of Retro-Aldol Cleavage Of Β-Hydroxy Amino Acids By Escherichia Coli L-Threonine Aldolase, Remsh Soumya Govinda

Theses and Dissertations

With over 140 vitamin B6 (Pyridoxal 5’-phosphate, PLP) dependent enzymes, serving vital roles in various transamination, decarboxylation, retro-aldol cleavage and synthesis pathways these enzymes constitute the most versatile catalytic systems in nature. Enzymes of this group have an inherent reaction as well as substrate specificity. A single co-factor namely, PLP is used by specific enzymes of this group to serve distinct roles during the catalytic reaction. An ordered evolutionary adaptation in these enzymes has led to specialization achieved by each enzyme for catalyzing specific reactions. L-Threonine aldolase (L-TA) is one such PLP- dependent enzyme that catalyzes the retro-aldol cleavage of …

The Effect Of Cobalt Protoporphyrin And Cobalt Chloride On Heme Oxygenase Expression And Protection From Deoxycholate-Induced Apoptosis, Tina Lawson

Theses and Dissertations

The inner surface of the stomach is lined by a mucous membrane known as the gastric mucosa. The integrity of the gastric mucosa is critical for protecting the stomach from the low pH and proteolytic environment within the lumen. Both clinically and experimentally, exposure of gastric mucosal cells to bile salts is known to cause injury. Bile salts present in duodenogastric reflux are thought to play a significant role in gastric ulcer formation and alkaline gastritis. In vitro, studies using physiologic concentrations of the secondary bile salt, deoxycholic acid, indicate that bile salts can induce apoptosis in cultured human gastric …

Role Of Pyridoxine 5'-Phosphate Oxidase In Metabolism And Transfer Of Pyridoxal 5'-Phosphate, Sayali Karve

Theses and Dissertations

Deficiency of vitamin B6 due to mutations in key B6 metabolizing enzymes is suspected to contribute to several pathologies. Vitamin B6 in its active form, pyridoxal 5’-phosphate (PLP) is a cofactor for over 140 known B6 requiring (or PLP-dependent) enzymes, that serve vital roles in many biochemical reactions. There are three primary vitamin B6 forms, pyridoxine (PN), pyridoxamine (PM) and pyridoxal (PL) which are phosphorylated to pyridoxine 5’-phosphate (PNP), pyridoxamine 5’-phosphate (PMP) and PLP respectively. Pyridoxal kinase (PLK) and pyridoxine 5’-phosphate oxidase (PNPO) are the key enzymes involved in both salvage and de novo pathways of PLP biosynthesis. Mutations in …

The Development And Use Of A Geographic Information System For Evaluating The Association Between Pesticide Exposure And Prostate Cancer, Kristen Wells

Theses and Dissertations

Abstract 1 – A Geographic Information System for Evaluating Residential Pesticide Exposure and Prostate Cancer Incidence Agricultural pesticide exposure is hypothesized to be a risk factor for prostate cancer, and such exposures are of particular concern for men living in farming communities where large-scale pesticide applications occur. Prostate cancer incidence data were obtained from the State Health Registry of Iowa for the years 1996 through 2006, and county and census tract level age-adjusted incidence rates were calculated. Historical crop-specific land use records and pesticide sales data for the state of Iowa during 1990 were integrated into a geographic information system …

The Transcriptional Regulation Of Hla-E By Interferon-Gamma In Tumor Cells, Quintesia Grant

Theses and Dissertations

The human Class Ib gene, HLA-E inhibits both Natural Killer Cells and a subset of CD8+ cytotoxic T lymphocytes by engaging the CD94/NKG2A inhibitory receptor. IFN-γ induces the expression of HLA-E as well as Class Ia molecules, which are required for the killing of target cells. Since HLA-E has negative effects on immune killing of target cells, we have sought to identify locus specific mechanisms of IFN-γ induction in order to identify molecular targets for selective activation of Class Ia genes, but not HLA-E. We have previously identified a unique upstream IFN-γ response region in the HLA-E promoter and showed …

Pyridoxal Kinase: Its Role In Vitamin B6 Metabolism, Jigarkumar Desai

Theses and Dissertations

Pyridoxal kinase (PL kinase) and pyridoxine 5’-phosphate oxidase (PNP oxidase) are the two vitamin B6 salvage enzymes involved in metabolism of the primary inactive vitamin B6 (pyridoxal, pyridoxine and pyridoxamine) into the active cofactor form, pyridoxal 5’-phosphate (PLP). PLP, arguably the most important vitamin, is required by numerous vitamin B6 (PLP-dependent) enzymes as a co-factor. These enzymes serve vital roles in the metabolism of glucose, lipids, amino acids, heme, DNA/RNA and many neurotransmitters. High levels of vitamin B6 are linked to neurotoxicity, due to the non-specific interactions of PLP with non-B6 proteins. This problem is controlled, in part, by maintaining …

Estimating The Reliability Of Concept Map Ratings Using A Scoring Rubric Based On Three Attributes, Laura Jimenez

Theses and Dissertations

Concept maps provide a way to assess how well students have developed an organized understanding of how the concepts taught in a unit are interrelated and fit together. However, concept maps are challenging to score because of the idiosyncratic ways in which students organize their knowledge (McClure, Sonak, & Suen, 1999). The construct a map or C-mapping" task has been shown to capture students' organized understanding. This "C-mapping" task involves giving students a list of concepts and asking them to produce a map showing how these concepts are interrelated. The purpose of this study was twofold: (a) to determine to …

Double-Strand Break Repair Mechanisms In Human Embryonic Stem Cells, Bret Adams

Theses and Dissertations

Central to the progression of all organisms is the maintenance of a stable genome despite continuous insults arising from genotoxic and environmental stresses. Embryonic stem cells show promise for treatment of a variety of diseases as well as for providing normal human tissue to conduct scientific research. A major obstacle for their application is that genomic instability arises in stem cells after prolonged cell culture. The most detrimental form of DNA damage is the DNA double-strand break (DSB), which is managed by cells through complex mechanisms, designated the DNA damage response. There are two major types of DSB repair; homologous …