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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
101

Screening for Insulin Resistance in Patients with Liver Disease in Tertiary Centers

Ahmed, Waheeda Siddiqui, Ahmed, Waheeda Siddiqui January 2016 (has links)
Background: Liver is a vital organ that plays a major role in glucose production and regulationthroughout the body (Musso et al., 2012). Liver disease has long been linked with insulin resistance (IR), dating back to 1906 (Megyesi et al., 1967). IR has been found to be prevalent in a range of liver diseases, including chronic Hepatitis C Virus (HCV), hemochromatosis, and alcoholic liver disease (Goswami et al., 2014). Liver disease is highly prevalent in the United States population with 30 million people (or one out of ten Americans) suffering from some type of liver disease (Peery et al., 2015). Although research demonstrates a significant relationship between liver disease and IR, the University of Arizona (UA) hepatology clinic does not currently screen liver disease patients for IR. Homeostatic model assessment for insulin resistance (HOMA-IR) score is used to study IR in non-insulin resistant population. HOMA-IR score is calculated using formula fasting plasma glucose (mmol/l) times fasting serum insulin (mU/l) divided by 22.5 (Bonora et al., 2002). Low HOMA-IR (HOMA< 2.0) values indicate high insulin sensitivity, whereas high HOMA-IR (HOMA> 2.0) values indicate low insulin sensitivity (insulin resistance) (Bonora et al., 2002). Objective: The purpose of this quality improvement (QI) project is to show the prevalence of IR in euglycemic liver disease patients at the UA hepatology clinic by using their HOMA-IR scores as a screening tool. By screening euglycemic liver disease patients for IR based on their HOMA-IR score, providers at the UA hepatology clinic can prevent liver disease progression and complications associated with IR early on. By doing so, the providers can improve the quality of care for liver disease patients. An essential part of calculating HOMA-IR is the availability of labs (serum glucose and serum insulin). A part of this QI project is to determine if the UA hepatology clinic has necessary labs to calculate HOMA-IR for euglycemic liver disease patients. A related matter is whether there is a correlation between liver disease patients' HOMA-IR score and Model for End-stage Liver Disease (MELD) score. If there is a direct correlation between HOMA-IR and MELD scores, providers can identify severity and progression of liver disease in euglycemic liver disease patients. Design: A case control retrospective study. Study Questions: 1) Do UA Hepatology clinic providers order sufficient labs (fasting plasma glucose and fasting plasma insulin) to calculate HOMA-IR in euglycemic patients? 2) What is the prevalence of IR in euglycemic liver patients indicated by HOMA-IR score? 3) Is there any correlation between HOMA-IR score and MELD score in euglycemic liver disease patients? Participants: Data will be collected from 1000 liver disease patients' at the UA hepatologyclinic, a tertiary level referral center. Settings: Banner University Medical Center (UMC) in Tucson, Arizona from January 1, 2011 until December 31, 2014. Measurements: HOMA-IR score using serum fasting glucose and serum fasting insulin levels laboratory values. MELD score to identify the severity of liver disease in euglycemic liver disease patients. Results: Among 1000 patients, 506 (60.5%) were found to have a previous diagnosis of T2DMand 395 (39.5 %) were euglycemic liver disease patients (Figure 1). Out of the 395 euglycemic liver disease patients, 217 (55%) participants were found to have both insulin level and glucose11level in their charts; 178 (45%) euglycemic liver disease patients were missing either insulin level or glucose level needed to calculate HOMA-IR score (Figure 2). Of the 217 euglycemic liver disease patients, 54.8% of had HOMA-IR> 2 and 45.2% patients had HOMA-IR<2 (Figure 3). The Pearson Correlation between HOMA-R>2 and MELD scores was 0.092 and the significance value using 2-tailed was 0.321 (Table 4). Conclusion: The results showed a significant high prevalence of IR in euglycemic patients with HOMA-IR score> 2 (54.8%) compare to those patients with HOMA-IR score<2 (45.2%). Furthermore, about 178 (45%) euglycemic liver disease patients were missing either insulin level or glucose level needed to calculate HOMA-IR score. This is a significant number of patients missing important labs to identify them as high risk for IR. This QI project identified HOMA-IRas an important screening tool that should be used both in hepatology clinics and primary healthcare settings. Use of such tool will lead to improved quality of care for euglycemic liver disease patients.
102

Úloha proteinkinázy C v patogenezi inzulinové rezistence a jejích komplikacích / The role of protein kinase C in the pathogenesis of insulin resistance and its complications

Marková, Irena January 2010 (has links)
18 effects of TZDs are probably due to the remodeling of adipose tissue and increased adiponectin secretion. SUMMARY Studying the pathogenesis of insulin resistance and the role of PKC in insulin resistance In HHTg rats, elevated serum triglycerides and FFA were associated with the ectopic accumulation of triglycerides in tissues and reduced insulin sensitivity of peripheral tissues. Impaired glucose utilization in the peripheral tissues was associated with the reduced activity of GS in skeletal muscle. Decreased GS activity and glucose utilization in peripheral tissues indicate a possible defect in insulin signal transduction. In line with this, our results show that skeletal muscle IR was associated with the increased activation and translocation of PKC θ. Nutritionally induced obesity of HHTg rats resulted, in many cases, in the further deterioration of metabolic abnormalities associated with IR. We found that PKC θ, in particular, could contribute to the metabolic abnormalities associated with IR and obesity. The age-related increase in IR and deterioration of some parametres of carbohydrate and lipid metabolism, were not associated, in HHTg rats, with obesity but with increased serum levels of triglycerides and FFA. The age-related worsening of IR in HHTg rats was accompanied by increased...
103

Diabetes mellitus II. typu ve světle metabolického syndromu / Diabetes mellitus type II in the light of metabolic syndrome

Hrnčířová, Eliška January 2013 (has links)
DIABETES MELLITUS TYPE II IN THE LIGHT OF METABOLIC SYNDROME Author: Eliška Hrnčířová ¹ Tutor: MUDr. PharmDr. Kamil Rudolf, Ph.D. ¹, š ¹ Department of Clinical and Social Pharmacy, Charles University in Prague, Faculty of Pharmacy in Hradec Králové š II. intern gastroenterology clinic University Hospital Hradec Králové Background: My thesis deals with diabetes mellitus, a common chronic civilization disease, the essence of its creation, including the issue of the treatment, regime measures and it also mentions the associated health problems connected to the diagnosis. The Aim of the study: The main purpose of this work based on a small sample of patients was to verify their level of information and knowledge of the disease, compliance, participation in home blood glucose measurements and to determine the health complications associated with diabetes and its treatment. Methods: The study was carried out by questionnaire in a paper form. Data were obtained in a pharmacy during a short interview with 209 randomly selected diabetics type II. The questionnaire included two main characteristics of respondents (gender, age) and 6 simple targeted questions. Results: In the survey 59 % female and 41% male took part. The mean age of patients was 66.9 years. Respondents were diagnosed with DM on average 11.1...
104

Genetic and physiological investigations of monogenic disorders resulting in severe insulin resistance and aberrant adipose tissue distribution

Suliman, Sara January 2011 (has links)
Background: Regional adiposity and in particular central adiposity is associated with a hazardous metabolic profile, insulin resistance (IR), hypertension and increased cardiovascular mortality whilst gluteo-femoral fat (peripheral fat) is protective. Extreme phenotypes, especially those due to monogenic disorders, are experiments of nature, which have been pivotal in identifying genes involved in disease. The hypothesis tested in this thesis was that investigating individuals with monogenic causes of regional adiposity and IR would identify genes and physiological processes contributing to their phenotype. Methods: Two families with balanced translocations, sixty-nine patients with partial lipodystrophy and eight individuals with lipoma were investigated. Genetic investigations included mapping of balanced translocations using fluorescent in-situ hybridisation, DNA and cDNA sequencing and gene expression studies. In vivo investigations of adipose tissue included microdialysis and measurement of adipose tissue blood flow. Results: Genetic and physiological factors contributing to regional adipose tissue deposition and IR were identified in (1) individuals with lipodystrophy where mutations were identified in eleven families including one novel PPARG mutation V450M. Also a skinfold ratio was developed for the clinical diagnosis of partial lipodystrophy (2) a family with a balanced I translocation, IR and growth retardation, digenic disruption of INSR and CHN2 was identified, which accounted for the clinical phenotype (3) a family with a balanced translocation, central adiposity and peas associated with disruption of KIBRA (4) lipoma tissue relative to adjacent healthy subcutaneous tissue, where differential gene expression profiles were identified, we also demonstrated reduced metabolic flexibility and reduced lipolysis in lipoma relative to healthy adipose tissue despite no change in adipose tissue blood flow. Conclusion: Investigating individuals with extreme phenotypes and monogenic causes of regional adiposity and IR identified key genetic and physiological factors.
105

Obésité et insulino-résistance : étude longitudinale avec un traceur du transport du glucose, le [125l]-6-déoxy-6-iodo-D-glucose / Obesity and insulin resistance : longitudinal study using [125I]-6-déoxy-6-iodo-D-glucose, a tracer of glucose transport.

Henri, Marion 18 November 2011 (has links)
Les prévalences de l'obésité et du diabète de type 2 sont en nette augmentation et ces deux pathologies sont étroitement liées. Le diabète de type 2 est caractérisé par une incapacité des cellules b du pancréas à sécréter de l'insuline et par un défaut de transport du glucose en réponse à l'insuline dans les tissus insulino-sensibles (ou insulino-résistance, IR) : le muscle squelettique, le cœur et le tissu adipeux. L'utilisation d'un traceur du transport du glucose marqué à l'iode radioactif, le 6DIG, permet d'évaluer l'IR de façon non-invasive dans le cœur et le muscle squelettique. L'objectif de ce travail était d'étudier le développement éventuel de l'IR chez des animaux rendus obèses par des régimes enrichis en lipides et/ou en glucides. Aucune IR n'a été mise en évidence au cours des trois mois d'expérience dans le modèle animal d'obésité induite par régime alimentaire. Des études visant à optimiser le traitement des données obtenues avec le 6DIG ont également été réalisées. Celles-ci nous ont permis de montrer : 1- une amélioration de la reproductibilité de la méthode de mesure de l'IR cardiaque par utilisation de l'analyse factorielle, 2- la faisabilité d'une diminution de la durée des acquisitions de la radioactivité pour la mesure de l'IR musculaire, 3- la nécessité de réaliser des prélèvements sanguins pour l'utilisation de la modélisation mathématique afin de traiter les données. / Prevalence of obesity and type 2 diabetes are in constant augmentation worldwide and these pathologies are closely associated. Type 2 diabetes represents a combination of pancreatic -cell dysfunction and insulin-regulated glucose uptake impairment in insulin-sensitive tissues: heart, skeletal muscles and adipose tissues. The novel tracer of glucose transport [123I]-6DIG allows the non invasive determination of insulin resistance (IR) in the heart and skeletal muscle. The aim of this study was to evaluate the development of IR in rats fed a high-fat and/or high-carbohydrate diets. No insulin resistance was observed during the 3 month of experimentation in our animal model. Study to optimize 6DIG obtained data reduction was also made. The results show: (1) improvement of the method data reduction reproducibility in the heart with factor analysis technique, (2) a possibility to reduce radioactivity acquisition time to muscle IR measurement, (3) the need of blood sample to use mathematical modeling in the data reduction.
106

Metabolic and immune system cross-talk in human adipose tissue

Travers, Rebecca January 2015 (has links)
The overall aim of the work presented in this thesis was to further characterise aspects of metabolic and immune system cross-talk in human subcutaneous adipose tissue, with a particular emphasis on the potential role of T-lymphocytes in adipose tissue dysfunction and insulin resistance. Chapter 3 characterised macrophage and T-lymphocyte populations residing in adipose tissue from lean through to class I obese men. This work demonstrated that T-lymphocytes display increased activation with increased adiposity and that potential compensatory mechanisms may be present to help counteract adipose tissue inflammation. In Chapter 4, the same participants were exposed to a meal-based stimulus in order to examine the postprandial metabolic and inflammatory responses in blood and adipose tissue. Despite increased glucose and insulin responses in blood with obesity, there were no differences in inflammatory cytokine gene expression responses in adipose tissue. This suggests that mechanisms may be present to limit or dampen inflammatory output from adipose tissue after feeding in individuals with modestly increased adiposity. Chapter 5 examined metabolic and immune system changes to 50 % calorie restriction for 3 days, resulting in reduced serum leptin which was temporally associated with a reduction in blood T-lymphocyte activation. In adipose tissue, however, leptin gene expression/secretion was not reduced and neither was resident T-lymphocyte activation, indicating that there may be local tissue-specific responses of immune cells to caloric restriction. Chapter 6 characterised differences between obese individuals with either normal or impaired glucose tolerance, and their respective responses to 10 days of diet and activity modification. Overall, this thesis highlights key differences in properties of T-lymphocyte populations with increasing levels of adiposity and insulin resistance together with responses in adipose tissue and the immune system in times of feeding, severe calorie restriction and glucose lowering diet and activity.
107

Efeito do tabagismo passivo e do exercício físico associado sobre a expressão de transportador de glicose GLUT4 em músculos de ratos /

Silva, Patrícia Ebersbach. January 2009 (has links)
Orientador: Patrícia Monteiro Seraphim / Banca: Ubiratan Fabres Machado / Banca: Ercy Mara Cipulo Ramos / Resumo: O tabagismo altera o metabolismo celular em vários aspectos e evidências apontam que este pode desencadear um quadro de resistência à insulina e, em longo prazo, Diabetes tipo 2. Dentre as alterações metabólicas mais importantes associadas à resistência à insulina, encontra-se a alteração na quantidade de transportador de glicose GLUT4 disponível na membrana plasmática de tecido muscular e tecido adiposo. No entanto, a atividade física aparece como um dos fatores que poderia modificar o risco dos indivíduos desenvolverem resistência insulínica e/ou diabetes, uma vez que pode aumentar a expressão da proteína e do RNAm do transportador de glicose GLUT4, estimulando o transporte de glicose por uma via independente da via de sinalização da insulina. Dentro deste contexto, este trabalho teve por objetivo avaliar o efeito do tabagismo e de atividade física moderada associada sobre a sensibilidade à insulina em músculos de ratos, através da quantificação de proteína e do RNAm do transportador de glicose GLUT4. Para a realização deste estudo foram utilizados ratos Wistar, divididos em 4 grupos: (CS) grupo controle, (CE) controle exercitado, (FS) fumante sedentário e (FE) fumante submetido a exercício físico. Os grupos FS e FE foram submetidos à combustão dee4 cigarros/vez, 30 minutos, 2x/dia, durante 60 dias. Os grupos CE e FE executaram protocolo de exercício em esteira rolante, 60 dias, 60 minutos por sessão... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Cigarette smoking changes the cellular metabolism in many aspects and evidences suggest that it is related to insulin resistance and type 2 diabetes. Within the metabolic alterations associated to insulin resistance we can mention disturbs on GLUT4 content in plasma membrane of muscle e adipose tissue. However, physical activity appears as a factor that could modify the risk for these pathologies, increasing GLUT4 expression and stimulating glucose transport, in an independent-pathway of insulin signaling. In this context, this study aimed to evaluate the effect of smoking and moderated physical activity on insulin sensitivity in muscle of rats, by quantifying GLUT4 protein and mRNA. For this study, it was used Wistar rats divided into 4 groups: control (CS), control submitted to an exercise protocol (CE), sedentary smoker (FS) and smoker submitted to an exercise protocol (FE). The FS and FE groups were submitted to cigarette smoke exposition, 4 cigarettes/30 min./twice a day for 60 days. Groups CE and FE performed running on a treadmill for 60 days during 60 minutes per session... (Complete abstract click electronic access below) / Mestre
108

Estudo dos mecanismos envolvidos no desenvolvimento de resistência à insulina em ratos com lesão periapical /

Pereira, Renato Felipe. January 2018 (has links)
Orientador: Doris Hissako Sumida / Banca: João Cesar Bedran de Castro / Banca: Fabio Santos de Lira / Banca: José Antunes Rodrigues / Banca: Sérgio Eduardo de Andrade Perez / Resumo: Nos últimos anos, a relação entre infecções orais e desordens sistêmicas tem se consolidado como área de grande interesse na comunidade cientifica médica e odontológica. A lesão periapical (LP) é caracterizada como uma inflamação oral e está associada ao aumento da quantidade de citocinas pró-inflamatórias que possivelmente induzem resistência insulínica (RI). A RI é definida como a incapacidade dos tecidos periféricos em responder adequadamente às concentrações fisiológicas deste hormônio, no entanto, os mecanismos que causam RI não são totalmente compreendidos. Estudos anteriores do nosso laboratório observaram que a LP promove aumento das concentrações plasmáticas de TNF-α, prejuízos na transdução do sinal insulínico e redução do conteúdo de GLUT4 na membrana plasmática em tecido muscular esquelético, indicando uma relação entre LP e RI. Tais achados evidenciam a necessidade de realizar mais estudos para verificar os mecanismos envolvidos nestas alterações. O presente estudo, conduzido em ratos com LP, teve como objetivos: 1) calcular o índice HOMA-IR a partir dos concentrações plasmáticas de glicose e insulina 2) avaliar conteúdo total das proteínas inflamatórias (JNK, IKKα/ e TNF-) no músculo gastrocnêmio (MG) e o grau de fosforilação de JNK e IKKα/ no mesmo tecido; 3) verificar a presença de macrófagos infiltrados por meio da detecção da proteína F4/80 em MG; 4) quantificar a expressão de fatores de transcrição envolvidos com a diferenciação de linfócitos no baço (T-... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In the last few years, the relationship between oral infections and systemic disorders has been consolidated as an issue of great interest in the medical and dental scientific community. The periapical lesion (PL) is characterized as an oral inflammation and is associated with an increase in the levels of pro-inflammatory cytokines that possibly induce insulin resistance (IR). IR is defined as the inability of peripheral tissues to respond adequately to the physiological concentrations of this hormone, however, mechanisms that cause IR are not fully understood. Previous studies performed by our laboratory have found that PL promotes an increase in plasma TNF-α concentrations, impairment of insulin signal transduction, and reduction of plasma membrane GLUT4 content in skeletal muscle tissue, indicating a relationship between PL and IR. These findings highlight the need for further studies to verify the mechanisms involved in these changes. The present study was conducted in rats with PL and aimed: 1) to calculate the HOMA-IR index from the plasma glucose and insulin levels 2) to evaluate the total content of the inflammatory proteins (JNK, IKKα/β and TNF-α) in the gastrocnemius muscle (GM) and the JNK and IKKα/β phosphorylation status in the same tissue; 3) to verify the presence of infiltrated macrophages by F4/80 protein detection of in GM; 4) to quantify the expression of transcription factors involved in the lymphocytes differentiation into spleen (T-bet, GATA3 and FOXP3);... (Complete abstract click electronic access below) / Doutor
109

The role of nitrate-reducing oral bacteria in the etiology of insulin resistance and elevated blood pressure

Goh, Charlene Enhui January 2018 (has links)
Increasing evidence suggests that the oral microbiome is highly relevant to cardiometabolic outcomes. Associations between the oral microbiome and extra-oral outcomes are most commonly hypothesized to result from a chronic inflammatory response to a dysbiotic oral microbiome. However, an alternative mechanism hypothesized to link the oral microbiome to cardiometabolic risk is via the production of nitric oxide, a physiologically important gaseous transmitter. The enterosalivary nitrate-nitrite-nitric oxide pathway of nitric oxide generation is dependent on the presence of nitrate-reducing oral bacteria in the mouth to reduce salivary nitrates to nitrite, which are then swallowed and made systemically bioavailable for further reduction into nitric oxide in the blood vessels and tissues. Thus, this pathway presents a mechanism for oral bacteria to exert a beneficial influence on cardiometabolic health. The overall objective of this dissertation is to advance the understanding of the role of nitrate-reducing oral bacteria in cardiometabolic outcomes in a population setting. This objective was met using three aims. First, a systematic literature review was conducted to identify and assess the associations between nitrate-reducing oral bacteria and insulin resistance, plasma glucose, diabetes, blood pressure and hypertension found in the existing literature. The literature review found no study that explicitly tested the hypothesis of an association between nitrate-reducing oral bacteria and the cardiometabolic outcomes of interest. In addition, there were very few observed associations between nitrate-reducing oral bacteria and these cardiometabolic outcomes, and the findings were inconsistent across studies. Secondly, the associations between nitrate-reducing oral bacteria and insulin resistance, plasma glucose, blood pressure, prediabetes and hypertension were assessed using baseline data from a cohort of diabetes-free participants. Increased levels of oral nitrate-reducing bacteria were associated with lower insulin resistance, plasma glucose and mean systolic blood pressure cross-sectionally, but no associations were found with prediabetes and hypertension. Finally, as dietary nitrate intake influences the level of salivary nitrate in the mouth for the nitrate-reducing oral bacteria to act on, the associations between dietary nitrate and insulin resistance, plasma glucose, blood pressure, prediabetes and hypertension were assessed. No clear associations between higher dietary nitrate intake and the cardiometabolic outcomes were found. However, there was some indication that higher dietary nitrate intake was associated with lower systolic blood pressure. The interaction of dietary nitrate intake with nitrate-reducing oral bacteria was then considered, but no evidence of such interaction was found. Overall, the results of this dissertation suggest that higher levels of nitrate-reducing oral bacteria may confer health benefits across the range of bacterial levels likely observed in human populations. These findings help inform future public health research aimed at utilizing the enterosalivary pathway of nitric oxide generation to improve cardiometabolic health.
110

Insulin Regulation of Reverse Cholesterol Transport

Lee, Samuel January 2019 (has links)
Insulin resistance and type 2 diabetes are pathogenetically linked to increased risk of cardiovascular disease. While insulin resistance is defined by a dysregulation in hepatic insulin signaling, it is unclear how this impairment relates to the development of cardiovascular disease. Recently, there has been evidence showing that in insulin resistant individuals, cardiovascular disease is associated with a defect in reverse cholesterol transport – the cardioprotective process by which excess cholesterol is removed from the periphery, and returned to the liver for biliary excretion. Reverse cholesterol transport is facilitated by high-density lipoprotein (HDL) metabolism. Thus, malfunction in HDL turnover during reverse cholesterol transport may contribute to the buildup of atherosclerotic plaques, and subsequent cardiovascular disease in insulin resistant individuals. In this thesis, we seek to establish a better understanding of HDL metabolism and reverse cholesterol transport, as they relate to key transcription factors that mediate hepatic insulin signaling, namely the insulin-repressible forkhead transcription factors, FoxO1, FoxO3, and FoxO4 (FoxOs). We demonstrate that mice with liver-specific triple FoxO knockout (L-FoxO1,3,4) have increased HDL-cholesterol (HDL-C), associated with decreased expression of HDL-C clearance factors, scavenger receptor class B type I (SR-BI) and hepatic lipase, and defective selective uptake of HDL-cholesteryl ester by the liver. As such, we uncover a novel mechanism by which HDL-mediated reverse cholesterol transport to the liver is regulated by the hepatic insulin-->FoxO signaling pathway.

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