Type 2 diabetes mellitus affects over 100 million people worldwide. It is characterized by various metabolic abnormalities such as insulin resistance, aberrant insulin secretion, hyperglycaemia and a cluster of cardiovascular risk factors, including increased oxidative stress. It is associated with microvascular complications and increased potential of macrovascular disease. The aim of the studies described in this thesis was to test the hypothesis that oxidant stress contributes to an altered vascular function and impaired insulin regulation in a pre-diabetic animal model- the obese Zucker rats. The first objective was to develop new methods to measure endothelial function in animal disease models. Firstly, without autonomic control - the in situ perfused hindquarters, and secondly, with autonomic control - the in vivo Doppler ear blood flow. The obese Zucker rat was shown to have increased oxidative stress, as measured by plasma 8-epi-PGF2a,. It also had high insulin and glucose levels and impaired glucose disposal. Obese rats also had increased agonist-induced nitric oxide-dependent endothelial responses; these were further enhanced by insulin in a macrovascular preparation, but were impaired by insulin in a resistance vessel bed. Following dietary treatment with the antioxidants, the obese plasma insulin/glucose ratio was improved. However, vitamin E blunted the enhanced endothelial-dependent vasodilator responses, and decreased plasma levels of 8-epi-PGF2a. In contrast, pro-oxidant treatment with hydroquinone and buthionine-sulphoximine impaired the plasma insulin/glucose ratio, abolished endothelial hyperactivity but increased plasma 8-epi-PGF2a levels. Interestingly, fructose protected against pro-oxidant-induced increases in plasma 8-epi-PGF2a levels and further increases in glucose-induced plasma insulin. In summary the redox status in obese Zucker rats was modified with antioxidant and prooxidant treatment. This resulted in compensatory changes in glucose disposal and endothelial function. Impaired endothelial function may initiate "damage" especially in those individuals susceptible to syndrome X, leading to insulin insensitivity and vascular dysfunction in type 2 diabetes.

Gao, Zhibo. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 147-157). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Liu, Xin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 157-164). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

nÃo hà / A diabetes à considerada um fator de risco significativo para a ocorrÃncia de doenÃas periodontais. Entretanto, à necessÃrio que estudos a respeito deste assunto seja realizado em diferentes populaÃÃes, com diferentes caracterÃsticas. O objetivo deste estudo transversal foi avaliar os parÃmetros clÃnicos periodontais de diabÃticos do tipo 2 com diferentes padrÃes de controle glicÃmico. Foram selecionados portadores desta doenÃa, de ambos os gÃneros, residentes na sede do municÃpio de Sobral - CearÃ. Estes deveriam ser nÃo-fumantes, com idade igual ou superior a 40 anos, possuir pelo menos 6 dentes na arcada dentÃria e fazer uso de medicaÃÃo hipoglicemiante. Os indivÃduos foram submetidos ao exame clÃnico periodontal: Ãndice de placa visÃvel (IP), sangramento gengival (IG), sangramento à sondagem (SS), profundidade de sondagem (PS) e recessÃo gengival (RG), realizado por um examinador previamente calibrado. Os indivÃduos foram divididos em trÃs grupos de acordo os nÃveis de hemoglobina glicada â Hb1Ac (Controlados - C: Hb1Ac ≤ 7%, n=103; Descontrolados - D: 7,1% ≤ Hb1Ac ≤ 9%, n= 60; Elevado Descontrole = E: Hb1Ac ≥ 9,1%, n=22). NÃo foram observadas diferenÃas significantes em relaÃÃo Ãs mÃdias de idade em anos, mÃdia de dentes presentes, IP, IG e SS. Verificou-se diferenÃa significante entre os grupos para as mÃdias de Hb1Ac e tempo de diagnÃstico da doenÃa. NÃo foi verificada associaÃÃo estatisticamente significante entre elevados nÃveis glicÃmicos e a maior presenÃa de dentes e de sÃtios periodontais com PS ≥ 6 mm. Entretanto quando foram analisados apenas os indivÃduos que apresentaram 20 ou mais dentes isso foi observado. Assim, pÃde-se concluir que o pobre controle glicÃmico dos diabÃticos do tipo 2, foi associado a maior presenÃa de periodontite apenas nos indivÃduos com elevado nÃmero de dentes. / Diabetes is a significant risk factor for the occurrence of periodontal diseases. Studying the relationship of both diseases in different populations with heterogeneous characteristics are still necessary to better understand them. The aim of this cross-sectional study was to evaluate the clinical periodontal parameters of type 2 diabetes patients with different levels of glycemic control. There were selected type 2 diabetics residing in the urban area of Sobral, Ceara. They must be non-smokers, aging 40 years or more and presenting at least and 6 teeth in their mouth. All had to be using any medication to control the glycemic level. Subjects were assigned to three groups based on their respective glycated hemoglobin levels - Hb1Ac (Control - C: Hb1Ac ≤ 7%, n=103; Moderate control - M: 7,1% ≤ Hb1Ac ≤ 9%, n= 60; Poor control = P: Hb1Ac ≥ 9,1%, n=22). The following clinical data were obtained from all patients: Plaque Index (PI), Gingival Index (GI), bleeding on probing (BOP), probing depth (PD) and gingival recession (GR). The mean age, number of teeth, PI, GI and BOP did not show any significance between groups. But this was observed for Hb1Ac mean levels and time of diabetes diagnosis. The presence of at least one periodontal site with PD ≥ 6 mm was considered for the diagnosis of periodontitis. There was no association between the increase of the glycemic level and the presence of periodontitis. However, data from patients presenting at least 20 teeth showed a significant association between periodontal diseases and higher glycemic levels. It can be concluded that the poor glycemic control was associated to the presence of periodontitis only in subjects with high number of teeth.

Proefschrift Universiteit van Amsterdam. / Met samenvatting in het Nederlands. - Met lit. opg.

Diss. (sammanfattning) Umeå : Univ., 2008. / Härtill 5 uppsatser.

Diss. (sammanfattning) Göteborg : Univ., 2007. / Härtill 3 uppsatser.

Diss. (sammanfattning) Umeå : Univ., 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning) Umeå : Univ., 2007. / Härtill 4 uppsatser.

Thesis (Ph.D.). / Written for the Dept. of Epidemiology and Biostatistics. Title from title page of PDF (viewed 2008/05/09). Includes bibliographical references.