Many adolescents with type 1 diabetes (T1DM) have suboptimal glycaemic control, increasing the risk of diabetic complications. This thesis explores some of the causes, consequences and therapeutic options for adolescents with T1DM and poor glycaemic control. Insulin resistance occurs in T1DM and normal puberty and contributes to poor glycaemic control. The effect of rosiglitazone, an insulin sensitizer, in addition to insulin on the glycaemic control of adolescents with T1DM was tested using a randomized, double blind placebo controlled trial. Treatment with rosiglitazone did not improve HbA1c, however there was a significant reduction in insulin dose and adiponectin, suggesting improved in insulin sensitivity. Insulin sensitivity by euglycaemic hyperinsulinaemic clamp varied widely between individuals and there was no consistent pattern with rosiglitazone. Potential markers of insulin resistance in T1DM were examined. Total and high molecular weight (HMW) adiponectin levels were lower in children and adolescents with T1DM than controls. HMW adiponectin was significantly associated with other markers of insulin resistance, such as insulin dose, body mass index standard deviation score (BMI-SDS), age, pubertal stage and duration of diabetes. There is increasing evidence that insulin resistance may play a role in T1DM complications. The natural history and risk factors for the development of microalbuminuria was described using a retrospective cohort study of 972 children and adolescents. Most cases of microalbuminuria were transient. Apart from baseline albumin excretion rate, HbA1c and age at diagnosis, other predictors of subsequently developing persistent microalbuminuria included several markers of insulin resistance (higher cholesterol, BMI-SDS, and insulin dose). In addition to insulin resistance, there are many other factors that contribute to glycaemic control. The role of the variability in carbohydrate intake was assessed using questionnaires and food diaries. Although carbohydrate consumption varied by approximately 45grams each day, it had no significant correlation with HbA1c. The impact of socioeconomic status, quality of life and health care delivery is discussed by comparing glycaemic control of children with T1DM in three diabetes centres. A model for the factors associated with poor glycaemic control in adolescents with T1DM is proposed, and the challenges of research and clinical practice in this population are discussed.

The present study aimed to examine factors that predict glycemic control in Hispanic youths. Secondary aims included developing and evaluating Spanish translations of three measures commonly used in research with youths with type 1 diabetes and examining factors associated with diabetes self-management in this population. Data was collected at three sites through interviews, questionnaires, and medical chart review. Participants included 117 Hispanic diabetic youths (10 to 17 years old) and their caregiver. 15% of the youths who participated were born outside of the continental U.S. and 57% were first generation born in the U.S. Translations of the Diabetes Self-Management Profile, Diabetes Social Support Questionnaire-Family version, and the Family Environment Scale?s Organization subscale had adequate reliability and showed evidence of concurrent validity. Primary analyses indicated that parent education, occupation, and household income are all significant predictors of glycemic control in Hispanic youth. In addition, global ratings of diabetes self-management on the DSMP predicted control in this population. Family factors did not contribute directly to glycemic control after controlling for sociodemographic and disease variables. However, older age, more acculturation, and language barriers were associated with poorer self-management. Additionally, family support and organization significantly contributed to self-management.

Vaccination has proven a cost-effective method of managing infectious diseases, but attempts to develop an effective fetal vaccine have proven difficult due to the immaturity of the immune system and the propensity of the developing immune system to induce tolerance to immunizing antigens. This thesis is concerned with the induction of specific immunity in the second trimester ovine fetus using the oral DNA immunization method. In utero oral delivery of naked DNA plasmid was selected as the method of immunization due to previous successes in the third trimester ovine fetus and the immunostimulatory properties of the bacterial DNA backbone, which may help overcome developmental tolerance. Transfection and expression studies in the third trimester ovine fetus revealed the oral mucosal epithelium as the primary site of transgene expression and functionally active antigen was also localized to lymph nodes draining the oral cavity. Efficient transfection and expression of plasmid following oral delivery was specific to the fetus and correlated with a lesser degree of epithelial differentiation. Oral DNA delivery in the second trimester resulted in detection of transgene activity in 100% of treated fetuses and the level of transgene activity was greater than in fetuses treated in the mid-third trimester. Using a plasmid encoding the gene for bovine herpesvirus-1 truncated glycoprotein D (tgD), immunization studies were then conducted in the second trimester fetus. A new lower age limit for fetal immunization was established at 55-60 days gestation (gestation period is 148 days), which coincides with the appearance of lymphocytes in peripheral tissues. Antigen-specific antibody, interferon-× responses and/or neonatal anamnestic responses were detected in 66% of fetuses immunized between 55 and 84 days gestation. The duration of fetal primary immune responses was equivalent to that achieved in young lambs following optimized DNA vaccination, but the magnitude of fetal immune responses was limited. The persistence of immune memory from the second trimester to birth was consistent with experimental data which showed that the duration of immune memory had a stronger correlation to the duration, as compared to the magnitude, of the primary antibody response. Overall, the experiments within showed that oral DNA immunization of the early second trimester fetus is feasible and not associated with the induction of tolerance. These findings suggest that it may be possible to protect against mother-to-child transmission of infectious pathogens by targeting protection at the level of the fetus.

Vaccination has proven a cost-effective method of managing infectious diseases, but attempts to develop an effective fetal vaccine have proven difficult due to the immaturity of the immune system and the propensity of the developing immune system to induce tolerance to immunizing antigens. This thesis is concerned with the induction of specific immunity in the second trimester ovine fetus using the oral DNA immunization method. In utero oral delivery of naked DNA plasmid was selected as the method of immunization due to previous successes in the third trimester ovine fetus and the immunostimulatory properties of the bacterial DNA backbone, which may help overcome developmental tolerance. Transfection and expression studies in the third trimester ovine fetus revealed the oral mucosal epithelium as the primary site of transgene expression and functionally active antigen was also localized to lymph nodes draining the oral cavity. Efficient transfection and expression of plasmid following oral delivery was specific to the fetus and correlated with a lesser degree of epithelial differentiation. Oral DNA delivery in the second trimester resulted in detection of transgene activity in 100% of treated fetuses and the level of transgene activity was greater than in fetuses treated in the mid-third trimester. Using a plasmid encoding the gene for bovine herpesvirus-1 truncated glycoprotein D (tgD), immunization studies were then conducted in the second trimester fetus. A new lower age limit for fetal immunization was established at 55-60 days gestation (gestation period is 148 days), which coincides with the appearance of lymphocytes in peripheral tissues. Antigen-specific antibody, interferon-× responses and/or neonatal anamnestic responses were detected in 66% of fetuses immunized between 55 and 84 days gestation. The duration of fetal primary immune responses was equivalent to that achieved in young lambs following optimized DNA vaccination, but the magnitude of fetal immune responses was limited. The persistence of immune memory from the second trimester to birth was consistent with experimental data which showed that the duration of immune memory had a stronger correlation to the duration, as compared to the magnitude, of the primary antibody response. Overall, the experiments within showed that oral DNA immunization of the early second trimester fetus is feasible and not associated with the induction of tolerance. These findings suggest that it may be possible to protect against mother-to-child transmission of infectious pathogens by targeting protection at the level of the fetus.

Environmental factors such as ambient temperature and oxygen availability are variation in different altitude. Individuals within a species, living in variable environments often display phenotypic plasticity by changing morphology, behavior, reproduction, and physiology to meet the individual¡¦s ability to survive demanding conditions. This study was aimed to investigate the expression of angiotensin receptor and nitric oxide synthase genes of individuals resided at differential altitude, in an attempt to find the role of these molecules in cardiovascular adaptation to altitude. Spiny rats (Niviventer coxingi) are widely elevational distributed in Taiwan. They were studied under more natural conditions to provide an ecological context data on physiological plasticity between the different altitudes. I examined the body weight, blood pressure, heart rate and the expression of angiotensin type 1 or type 2 (ATI or ATII) receptor and nitric oxide synthase (NOS) genes in tissues (cortex, hypothalamus, medulla, lung, heart, aorta, adrenal gland and kidney) of spiny rats resided at differential altitude and during the domesticated period. The results of the study showed that spiny rats resided at higher altitudes were lighter than that at lower altitudes (750 m: 178.6¡Ó35.8 g and 1600 m: 122.3¡Ó29.3 g). Spiny rats resided at 1600 m did not change their body weight during the domesticated period, but rats resided at 750 m gradually reduced their body weight. Blood pressure and heart rate were similar between rats resided at different altitudes, and did not change during the domesticated period. ATI receptor, endothelelial NOS (eNOS), inducible NOS (iNOS) and neuronal NOS (nNOS) mRNA expression in these tissues were similar between rats resided at different altitudes. ATII receptor mRNA expressed in these tissues under our detection limit. Rats resided at 750 m declined the level of nNOS in heart, when they were domesticated at 100 m. ATI receptor in kidney reduced at first, but subsequently increase to same level like native. Moreover, rats resided at 1600 m declined the level of iNOS in heart, when they were domesticated at 100 m. Together, these results indicate that heart rate, blood pressure, ATI receptor, eNOS, iNOS and nNOS mRNA expressions in these tissues were similar between rats resided at different altitudes. If there was no other compensatory mechanism, individuals resided at higher altitude were limited in low available oxygen. A reduced body weight could help in adaptation to high-altitude.

IL-1 is an essential pro-inflammatory factor in inflammation response. The effect of IL-1 is through binding to the IL-1 receptor that triggers the following signal transduction pathway. To study the role of IL-1 receptor-mediated signal pathway in inflammatory response, injecting P. aeruginosa into trachea of wild-type (WT) and type-1 IL-1 receptor knock-out (IL-1R1-/-) mice was used as the experimental model. Injecting bacterium into trachea of mice will induce pneumonia which increases accumulation of neutrophils, production of nitric oxide, expression of intercellular adhesion molecule-1 as well as many kinds of cytokines and causes the lung damage. The pneumonia-induced lung damage and inflammation at 24 hr after injecting P. aeruginosa into trachea were more severe in knock-out than in WT mice, as demonstrated by increases in extravasations of Evans blue dye (EBD), myeloperoxidase (MPO) activity, expression of iNOS, IL-1 beta and ICAM-1, and higher mortality of knock-out mice. The cause of the high mortality in knock-out mice was further investigated by culturing the lung and blood samples for bacterial counts. The bacterial counts of lung and blood of IL-1R1-/- mice were all higher than that of WT mice in 8 to 24 hr after injection of bacterium. Finally, chimeric mice (WT ¡÷ WT, IL1R1-/- ¡÷IL1R1-/-, WT ¡÷ IL1R1-/-, IL1R1-/- ¡÷ WT) were generated and used to determine the role of PMN cells of blood. Suggesting that increased amounts of bacteria in lung and blood is related to the higher mortality in knock-out mice and the type-1 IL-1 receptor is essential for mice to against pneumonia in this model.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 91-100).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 105-118).

Human enteroviruses (HEVs), particularly Coxsackie B viruses (CVBs), might trigger the onset of type 1 diabetes (T1D), either by direct infection of the insulin-producing beta-cells or by an indirect inflammatory response. The overall aim of this thesis was to study the tropism of HEVs in isolated human pancreatic cell clusters in vitro including virus effects on islet function, gene-expression and ultrastructure. Furthermore, the expression of the major CVB-receptor, CAR, was investigated in pancreatic tissue from T1D-related subjects and CVB-infected islets. Also, tissues and isolated islets from two adult organ-donors who died close to disease onset were studied.The results showed that beta-cells were destroyed through lytic infections with different strains of CVBs and that islets function did not depend on replication per se but on the degree of islet destruction. Virus particles were observed in beta-cells in association with insulin granules, however no virus replication or particles could be observed in the exocrine cell clusters, as opposed to in mice models. The virus-infected islets had a decreased expression of insulin mRNA and CAR mRNA/protein, possibly reflecting virus-killed beta-cells. Infected beta-cells contained a high number of insulin granules, which might indicate an impaired function.The in vivo studies showed presence of virus proteins in the islets of both donors who died close to onset of T1D and elevated expression of innate immunity genes, potentially indicating viral infection, but direct evidence is lacking. Both donors were immune-reactive for insulin but the isolated islets had an impaired or completely lacking glucose response. Ultrastructural analysis showed both damaged beta-cells and normal-looking beta-cells, indicating that the latter might still have the potential to function but were blocked. CAR-expression was significantly increased in T1D-related subjects which might indicate tissue damage and/or inflammation in these subjects.To conclude, these results showed that CVBs could infect human primary beta-cells, likely by binding to CAR and lead to functional abnormalities, indicating that they could cause T1D in vivo. Exocrine cells were not permissive to CVB, which raises the question if mice-models should be used to study human pancreatitis. Also, unique materials from two T1D organ-donors were described.

This thesis is an investigation of the factors that impact psychological adjustment and metabolic control in children and adolescents with type 1 diabetes. Studies suggest that aspects of the family environment (stressful life events, family functioning and parent mental health) and child characteristics such as age, sex, executive functioning and hopeful thinking impact psychological adjustment and metabolic control. There is also evidence that coping processes mediate these associations. The purpose of this study was to 1) explore and identify developmental differences in coping processes in a sample of children with T1D, 2) identify the family system characteristics that are associated with child coping processes and psychological adjustment, and 3) identify the family and child characteristics that impact metabolic control. Survey data were collected through convenience sampling from an outpatient hospital clinic. Children aged 8 to 17 completed self-reports of hopeful thinking and illness-related coping style. Caregivers provided demographic information and completed questionnaires on their child’s physical health, stressful life events, mental health, family functioning, as well as the child’s initiative, emotional control, and psychological adjustment. Ratings of child metabolic control (HbA1C) were also retrieved from hospital patient records. A predictive model examining direct and indirect contributions of the family environment and coping variables toward child adjustment and metabolic control was tested. Age and sex differences in children’s coping style were identified. Family functioning and parent mental health were found to predict child psychological adjustment. Coping processes, including avoidant coping, coping efficacy and executive functioning mediated relations between family functioning and child adjustment. Results provided partial support for a mediational model of family system characteristics that influence psychological adjustment in the sample. Family functioning and parent mental health had a direct impact on children’s psychological adjustment, as well as indirect effects on adjustment through coping processes (i.e., coping style, coping efficacy, initiative and emotional control). Child age was found to moderate some paths in the proposed model. Clinical and research implications are discussed.