Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
More information is available at Theses and Dissertations at University of Maryland Libraries.
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Item Relationship between disinhibition and metabolic control in adolescents with type 1 diabetes(2006-12-05) Sanchez, Lisa; Lejuez, Carl; Psychology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Given that adolescence poses a high-risk period for diabetes mismanagement, and consequently, threats to long-term health status, it is important to examine factors that contribute to individual differences in the propensity to exhibit poor management and engage in health incompatible behaviors. Importantly, researchers have identified personality constructs related to disinhibition, including impulsivity, sensation seeking, and risk-taking propensity, to be prospectively linked to engagement in real-world risk behaviors such as use of alcohol, nicotine, illegal drugs, and risky sexual behavior (Lejuez et al., 2002, 2003). However, this relationship has yet to be explored in adolescents with diabetes. Thus, the purpose of the current study was to examine whether disinhibition was related to metabolic control, and the extent to which self-management behavior and drug/alcohol use mediated this potential relationship. The sample consisted of 43 subjects with Type 1 diabetes aged 13-18 years who were recruited from diabetes clinics at Children's National Medical Center. Teens were assessed with self-report and behavioral measures of risk-taking and participated in an interview regarding self-management behaviors. Substance use and diabetes knowledge were measured by self report, and the glycosylated hemoglobin (HbA1c) test was used as a proxy for metabolic control. Results of partial correlational analyses indicated that disinhibition was not directly related to behavioral adherence, engagement in health incompatible behaviors, or glycemic control after controlling for race, gender, and insulin regimen type. Rather, results of regressional analyses suggested that sample characteristics, particularly race and insulin regimen, are the key variables in assessing overall management in adolescence. Results may have important implications for the prevention and treatment of morbidity associated with diabetes.Item Campylobacter jejuni/coli - Host Intestinal Epithelial Cell Interaction(2006-08-15) zheng, jie; meng, jianghong; Food Science; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Campylobacter jejuni/coli have been known to be major bacterial causes of human gastroenteritis worldwide for decades. Regarding its pathogenicity, little is known yet. A better understanding of the pathogenic mechanisms will provide important information, not only for generating molecular markers to differentiate pathogenic strains versus non-pathogenic ones; but also for developing rational strategies to prevent and control Campylobacter-caused disease. The objectives of this study were to characterize the pathogenic abilities of various C. jejuni/coli retail meat isolates, including their abilities to adhere to, invade into and transmigrate across human epithelial cells, to examine the role of NF-κB pathway in IL-8 secretion induced by Campylobacter, and to identify C. jejuni-specific adherence/invasion genes during host pathogen interaction. It was found that the adherence and invasiveness of total 43 Campylobacter retail meat isolates in human intestinal epithelial T84 cell model indicated that C. jejuni/coli present in retail meat were considerably diverse in their ability to adhere to and invade human epithelial cells. Meanwhile, eight putative virulence genes, determined by PCR, were shown to be widespread among the Campylobacter isolates. C. jejuni /coli-induced proinflammatory cytokine Interleukin (IL)-8 secretion in polarized human colonic epithelial cells T84 was examined, and the role of NF-κB pathway in Campylobacter-induced IL-8 secretion was determined. Data suggested that C. jejuni/coli induce basolateral-polarized secretion of IL-8 in human intestinal epithelial cells, and C. jejuni-induced IL-8 secretion is NF-κB-dependent. The effort to identify C. jejuni-specific adherence/invasion genes during host pathogen interaction by using restriction fragment differential display PCR (RFDD-PCR) has been made. As a result, it was not successful. However this study still provides useful information and experience on the application of this technique for prokaryotic gene expression analysis during host pathogen interaction, which remains an unexplored area. In summary, Campylobacter retail meat isolates exhibited wide diversity in cell culture model in the ability of adherence, invasion and transmigration. As the first line defense, intestinal epithelium activates NF-κB and secretes proinflammatory cytokine IL-8 in response to Campylobacter infection. Multiple virulence factors have roles in Campylobacter-intestinal epithelial cell interaction.