Medicine and Health Sciences Commons^™

Characterization Of The Factors Associated With Sccmec Mobility In Staphylococcus Aureus, Michael James Noto

Theses and Dissertations

The gene encoding resistance to β-lactam antibiotics in the staphylococci is found on the chromosome in a genomic island designated Staphylococcal Chromosome Cassette mec or SCCmec. In addition to the resistance gene, mecA, SCCmec also contains site specific recombinase genes, ccrAB, that are capable of catalyzing the chromosomal excision and integration of SCCmec. The increasing prevalence of methicillin-resistant Staphylococcus aureus infections may be due, in part, to the transfer of SCCmec into successful methicillin-sensitive S. aureus lineages. In this work we attempt to better characterize the factors associated with SCCmec transfer, beginning with CcrAB-mediated SCCmec excision in a collection of …

Sodium Hypochlorite's Effect On Nickel-Titanium Rotary Instruments And Its Effect On Resistance To Fracture, Michael Shane Smith

Theses and Dissertations

The purpose of this study was to examine the effect of partial and total immersion in sodium hypochlorite on nickel-titanium rotary files and to determine whether resistance to fracture was influenced by the immersion time. One hundred K3™ and 100 ProFile® rotary files were either partially or totally immersed in 5.25% sodium hypochlorite for zero, one, five, thirty, or sixty minutes. After immersion, files were subjected to cyclic fatigue testing. Time to fracture was recorded and analyzed by a two-way ANOVA. Tukey's honest significant difference was used to identify any differences in immersion times. Within all ProFile groups and partial …

Immunohistochemical Study Of Phenotypes Of Dendritic Cells In Dental Pulps From Non-Carious And Carious Teeth, Melissa A. Harmon

Theses and Dissertations

Mature dendritic cells (DCs) in inflamed tissues may promote inflammation but the status of DCs in pulpitis is not known. We hypothesized that DC maturation would correlate with carious lesion depth and that CD4+ cells would be found in association with mature DCs. Pulps were collected from teeth exhibiting: (I) no caries (n=9), (II) shallow dentinal caries (n=5), and (III) deep caries (n=9). Pulpal tissues were cryo-sectioned and positive cells were examined with immunohistochemistry, Mature DCs (CD83+) were almost exclusively restricted to pulps from deep caries. Furthermore, CD209+ DCs in deep caries were elevated over other groups and CD209+ cells …

An Invitro Leakage And Viscosity Analysis Of Root End Filling Materials, Paul D. Clark

Theses and Dissertations

The purpose of this study was to determine if the viscosity of MTA Angelus Fluid is lower than that of Pro Root MTA and MTA Angelus; and to compare the viscosity, leakage and particle size of these materials to determine whether a relationship exists between these properties. The viscosity of each material was measured and compared with the Student's t test. MTA Angelus Fluid's viscosity was significantly lower than the other two materials tested. Microleakage of root end fillings was assessed in a passive diffusion model. Leakage groups were compared with a one-way ANOVA (p < 0.05). No significant difference was found. Particle size and shape were evaluated with the SEM. MTA Angelus Fluid has a lower viscosity than the other materials tested. There was no significant difference in the sealing ability of the three materials tested and there was no apparent variation in each material's particle size or shape.

The Role Of Inhibitory Interneurons In A Model Od Developmental Epilepsy, Patrick James Wolfgang

Theses and Dissertations

Epilepsy, defined by recurrent seizures, is the one of the most prevalent neurological disorders worldwide (World Health Organization 2007). While many forms of epilepsy are well-controlled by anti-epileptogenic medications, a significant portion of patients have intractable, i.e. untreatable, seizures. The etiology of these seizures is varied, but a significant cause, particularly for patients with intractable epilepsy is developmental malformation. In these cases, an error or interruption during the development of the neocortex produces a structural alteration. Such patients may have other neurological problems, but seizures are the most common symptom. The neuronal mechanisms that link malformation and cortical hyperexcitability are …

Analysis Of Mouse Eklf/Klf2 E9.5 Double Knockout: Yolk Sac Morphology And Embryonic Erythroid Maturation, Tina Kathy Lung

Theses and Dissertations

Krüppel-like factors (KLFs) are a family of transcription factors with 3 Cys2/His2 zinc fingers that regulate cell differentiation and developmental processes. EKLF is involved in primitive and definitive erythropoiesis; KLF2 is implicated in the development of primitive erythroid and endothelial cells of the vasculature. Using light and electron microscopy, the yolk sacs and dorsal aortae from EKLF/KLF2 double knockout (KO) E9.5 (embryonic day 9.5) were examined to determine whether these KLFs have compensatory functions in morphology of blood cells and vessels. EKLF/KLF2 double KO E9.5 erythroid, endothelial, and mesothelial cells had more severely abnormal morphology than WT and KLF2-/-. Flow …

Relationship Between Facial Attractiveness And Occlusal Treatment Outcomes: A Retrospective Study, Chad Eric Fowler

Theses and Dissertations

The goal of this study was to determine if a relationship exists between pretreatment facial attractiveness and posttreatment occlusal outcome in orthodontic patients. A randomized sample of forty-seven patients (26 males, 21 females) was selected for inclusion in this study. Orthodontic evaluators rated pretreatment patient photographs (frontal smile, frontal, profile) using a 100 mm visual analog scale (VAS). Occlusal outomes were evaluated using percentage reduction in weighted Peer Assessment Rating (PAR) index scores and the American Board of Orthodontics objective grading system (ABO-OGS). Spearman correlation coefficients were calculated to assess the relationship between pretreatment VAS attractiveness ratings and posttreatment occlusal …

Self-Care And Quality Of Life In Patients With Heart Failure, Chantira Chiaranai

Theses and Dissertations

Although it is well known that self-care reduces the frequency of hospital admissions and exacerbations and enhances quality of life (QOL) in heart failure (HF) patients, little is known about self-care in this population. Therefore, the study purpose was to examine relationships among selected individual characteristics (demographics, severity of illness, comorbidities, and social support), self-care strategies, and QOL using Reigel's Model of Self Care in Patients with Heart Failure as the guiding framework. In this descriptive correlational study, self-care was measured using the Self-Care of Heart Failure Index (SCHFI), which measures self-care maintenance (SC-Mt), self-care management (SC-Mn), and self-care self-confidence …

Visual Contributions To The Vestibulo-Ocular Reflex During Balance Recovery Tasks, Mark D. Diehl

Theses and Dissertations

Introduction: The Vestibulo-ocular reflex (VOR) is quantified by computing the ratio of head angular velocity and eye angular velocity (VOR Gain). This measure only includes head angular movements; linear translations are not accounted for. These investigations postulate an alternative method of VOR quantification, one that assesses retinal image stability during head angular and linear movements (Foveal fixation (FF)). This method was used to assess the role of vision in balance reactions. Methods: Experiment 1 : Ten Young subjects were fitted with an eye tracker linked to an EM kinematic recording system. This allowed for the recording of head, trunk and …

Cd23'S Role As A Negative Regulator Of Allergic Disease: In Vivo Effects Of Murine Cd23 Destabilization And Allelic Mutations, Jill Wallace Ford

Theses and Dissertations

Through underexpression and overexpression studies, CD23 has been shown to negatively regulate IgE production. To investigate CD23 destabilization and its effects on CD23 shedding and IgE synthesis in vivo, we utilized an anti-CD23 stalk monoclonal (19G5) which has previously been shown to enhance proteolysis of CD23 in vitro. Compared to isotype control-treated mice, mice injected with 19G5 displayed enhanced serum soluble CD23 and IgE. Because 19G5 injection substantially enhanced CD23 shedding, it was useful in investigating the identity of the CD23 sheddase. 19G5 enhanced CD23 shedding in ADAM8-/-, ADAM9-/-ADAM15-/-, and ADAM9-/-ADAM12-/-ADAM15-/- mice, ruling out these ADAMs as candidate CD23 sheddases. …

Resilience And Risk-Taking Behavior Among Thai Adolescents Living In Bangkok, Thailand, Patcharin Nintachan

Theses and Dissertations

The major purposes of this study were to determine the relationships among resilience, risk-taking behavior and personal characteristics of Thai adolescents living in Bangkok and to examine the differences in risk-taking behavior by school grades or gender. To accomplish these, a cross-sectional correlational research design was conducted. Resilience was measured by using the State-Trait Resilience Inventory developed by Hiew, Mori, Shirnizu and Torninaga.Risk-taking behavior was measured by the Risk-taking Behavior Questionnaire for Thai Adolescents which is a modified version of the 2003 Youth Risk Behavior Survey (YRBS) originally developed by the U.S. Centers for Disease Control and Prevention. In order …

Has Richmond, Virginia Become Safer In The Past Five Years (2002-2006)?: An Analysis Of Ambulance Data Regarding Penetrating Trauma Incidents, Ashleigh K. Mccabe

Theses and Dissertations

Introduction: The World Health Assembly declared violence as a worldwide public health problem. Homicides have been identified as a leading cause of death in the United States across all age groups. The national homicide rate for 2004 and 2005 are 5.5 and 5.6 per 100,000 population, respectively. The reported rates for Virginia are 5.2 (2004) and 5.6 (2005) per 100,000 population, showing a 16.9% increase. Richmond has been ranked as high as the sixth most dangerous among similar cities in the United States. This study examines penetrating trauma injuries identified through 9-1-1 calls as an indicator of the incidence of …

The Effect Of Income Level On The Relationship Between The Personal Support Matrix And Sustained Breastfeeding, Sandra Mann Gossler

Theses and Dissertations

The Healthy People 2010 Objectives for the population of the United States include the objective for women to sustain breastfeeding at a higher rate than they are currently.The American Academy of Pediatrics (AAP) now recommends that all infants be fed human milk for the first year of life instead of the previously recommended first six months of life. Breastfeeding initiation rates are rising, but breastfeeding duration rates continue to fall. It was hypothesized that the support system of the women may play a role in the duration of breastfeeding. The purpose of this research study was to investigate the support …

A Comparision Of Delta-9-Tetrahydrocannabinol Dependence In C57bl/6j Mice And Fatty Acid Amide Hydrolase Knock Out Mice, Brittany Leigh Alice Carlson

Theses and Dissertations

The idea that humans and laboratory animals can become physically dependent on marijuana or its primary psychoactive constituent, delta-9-tetrahydrocannabinol (THC), is gaining acceptance. However, there are no currently approved pharmacotherapies to treat cannabinoid withdrawal. The objective of this thesis was to evaluate whether elevating endogenous anandamide levels using mice lacking fatty acid amide hydrolase (FAAH), the enzyme responsible for anandamide metabolism, would ameliorate THC dependence. Mice were treated subchronically with a low or high THC dosing regimen and challenged with the CB1 receptor antagonist, rimonabant, to precipitate withdrawal. Following subchronic THC treatment, rimonabant precipitated a significant increase in paw flutters …

Obesity As A Risk Factor For Preeclampsia: Role Of Inflammation And The Innate Immune System, Tanvi Jayendra Shah

Theses and Dissertations

Obesity is a known risk factor for preeclampsia, but the reason for this risk is unknown. We sought to demonstrate how obese individuals are predisposed to preeclampsia by mechanisms involving inflammation and the innate immune system. First, we used immunohistochemical studies to identify neutrophil infiltration, NF-κB activation and COX-2 expression in vascular tissue of obese women. We then demonstrated similar neutrophil infiltration and vascular inflammation in preeclamptic women.We used in vitro experiments to test if neutrophils and their products, reactive oxygen species (ROS) and tumor necrosis factor-alpha (TNFα) can activate NF-κB and cause expression of its inflammatory products, COX-2, thromboxane …

Improving Life Satisfaction Of Elders Through Oral History: The Narrator's Perspective, Mary B. Ligon

Theses and Dissertations

Oral history is a method of preserving historical information through in-depth interviews. Because the process requires narrators to use remote recall while sharing their life experiences, it can also be considered a reminiscence-related activity. Before this study, the positive effects on narrators of providing an oral history were noted in the research literature but had not been evaluated through quantitative methods. Based on theoretical constructs of Erikson and Butler, it was hypothesized that participation in oral history interviews would improve the life satisfaction of narrators. Life satisfaction was operationalized and measured using the Life Satisfaction Index Version A (LSIA). The …

Impact Of Combat Stress On Mental Health Outcomes: Brfss Survey Data 2006, Emily Pedneau

Theses and Dissertations

Objectives: This study sought to determine the relationship between combat experience and mental health outcomes. The study sought to determine whether age was a significant factor in poor mental health outcomes. Methods: Multiple logistic regression (n = 195,048) and multiple linear regression (n = 264,154) were performed on the 2006 Behavioral Risk Factor Surveillance System (BRFSS) survey. Veteran status and a host of demographic and health status questions were analyzed in relation to diagnosis of anxiety or depressive disorder (multiple logistic regression) and to number of days poor mental health (multiple linear regression). Results: Diagnosis of anxiety or depression was …

The Quantitative Genetics Of Neurodevelopment: A Magnetic Resonance Imaging Study Of Childhood And Adolescence, James Eric Schmitt

Theses and Dissertations

Understanding the causes of individual differences in brain structure may give clues about the etiology of cognition, personality, and psychopathology, and also may identify endophenotypes for molecular genetic studies on brain development. We performed a comprehensive statistical genetic study of anatomic neuroimaging data from a large pediatric sample (N=600+) of twins and family members from the Child Psychiatry Branch at the NIMH. These analyses included variance decomposition of structural volumetric endophenotypes at several levels of resolution, voxel-level analysis of cortical thickness, assessment of gene by age interaction, several multivariate genetic analyses, and a search for genetically-mediated brain-behavioral relationships. These analyses …

Effects Of Ankle Support On Time To Stabilization Of Subjects With Stable Ankles, Raquel Elise Martin

Theses and Dissertations

The purpose of this study was to determine if prophylactic ankle tape and/or ankle braces improve dynamic stability in TTS measure. All subjects were healthy and had no prior history of ankle injuries. Data collection consisted of each subject performing a single leg jump-landing with ankle tape, ankle brace, combination of the two, and control (no tape or brace) conditions. Dynamic stability was assessed with time to stabilization force plate measure. Significant plane by ankle tape interaction (p=0.045) was found. No significant plane by ankle tape by ankle brace interaction (p=0.637), no significant ankle tape by ankle brace interaction (p=0.483), …

Anesthesia Clinical Performance Outcomes: Does Teaching Methodology Make A Difference?, Nina E. Mclain

Theses and Dissertations

Researchers have studied memory recall of crisis-oriented or emotional events in non-educational settings. However, within the health care field, there has been a limited study of the the concept of recall of crisis oriented or emotional events in& health care education. Crisis-oriented events such as natural disasters, acts of bioterroism, and industrial accidents, have been reported to impact memory. Patient safety is a primary focus in anesthesia education, appropriate crisis management is imperative to quality anesthesia care. Due to the critical nature of anesthesia delivery, there is a strong, constant need to develop methods that will enhance, support, and improve …

Vocational Rehabilitation Of Clients With Brain Injury: An Investigation Of Racial Disparity Within The Rehabilitation Services Administration (Rsa) 911 Database, Stephanie A. Kolakowsky-Hayner

Theses and Dissertations

Finding and maintaining employment is an ongoing problem for persons with disabilities, especially those with brain injuries. State vocational rehabilitation agencies are the primary authority responsible for providing employment-related services for individuals with disabilities throughout the United States. Little effort has been committed to identifying disparities in health and rehabilitation services provided to Americans with disabilities, particularly those with brain injuries. The purpose of this investigation was to utilize Aday and Andersen's Framework for the Study of Access to examine racial disparity within the Rehabilitation Services Administration 911 Database, and thus the vocational rehabilitation system, among clients with brain injury. …

Supporting Personhood In Dementia: Examining The Impact Of Volition On Function In Everyday Occupations, Christine L. Raber

Theses and Dissertations

Understanding volition and preferences for occupation is a critical underpinning of effective occupational therapy services that promote and preserve identity for persons with moderate dementia. Although it has been posited that this population has significant difficulty expressing volition for daily occupations, little research has examined the role of volition in guiding engagement in occupations. This phenomenological study provides an in-depth description and analysis of volition in eight persons with moderate dementia. Guiding questions related to understanding patterns of past life interests, outward demonstration of volition, volitional continuity. and the relationship of the social environment to volition and engagement in daily …

Transition From Health Maintenance Organizations To Consumer Driven Health Plans: Measurement Of Initial Impacts For Members With Chronic Conditions, Carl F. Goff

Theses and Dissertations

New consumer driven health insurance products are designed to contain health care costs by making consumers more accountable for the care they receive through being responsible for more cost sharing, making decisions regarding health care providers they will use, and increasing exposure to and use of health information for services and providers. Potential benefits of consumer driven products include increased information regarding personal health and a more knowledgeable patient base. Potential drawbacks of consumer driven products include negative impacts on consumers with chronic and complex health conditions.

The purpose of this study was to ascertain differences in health services utilization …