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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.
21

Estudo do metabolismo energético hepático e da via de sinalização da grelina na obesidade induzida por dieta ocidental / Hepatic metabolism energy study and ghrelin signaling pathway in the Western diet-induced obesity

Patricia Soares Pacheco 10 June 2015 (has links)
Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro / A obesidade é um dos maiores problemas de saúde pública que cresce em todo o mundo, resultante de um desequilíbrio entre ingestão alimentar e gasto energético. Pode-se dizer que a obesidade é o principal fator de risco para o desenvolvimento de doenças crônicas de maior prevalência como dislipidemias, doenças cardiovasculares, diabetes do tipo 2 e esteatose hepática não alcóolica, acarretando na redução da qualidade e expectativa de vida. A Grelina é um hormônio sintetizado pelo estômago, que atua em diferentes tecidos através de um receptor específico (GHS-R1a), incluindo hipotálamo e tecidos periféricos, como o fígado. Esse hormônio está envolvido no comportamento alimentar e adiposidade, modulando o armazenamento ou utilização dos substratos energéticos no coração, músculo esquelético, adipócitos e fígado, além disso, revela-se de grande importância na manutenção do metabolismo energético hepático. Estes dados suportam a hipótese de que as vias de sinalização responsivas à grelina são um importante componente da regulação do metabolismo energético hepático e da homeostase glicêmica. O objetivo deste trabalho, foi estudar o metabolismo energético hepático e a sinalização da grelina em camundongos Swiss adultos obesos submetidos a dieta ocidental rica em gordura saturada e carboidratos simples. Avaliamos o efeito desta dieta a partir do 21 dia de idade (desmame) até o 133 dia destes animais, através de parâmetros biométricos e bioquímicos, avaliação histomorfológica, respirometria de alta resolução, conteúdo de glicogênio hepático e conteúdo de algumas proteínas envolvidas na sinalização de insulina e grelina, além do metabolismo energético hepático. Baseado em nossos resultados observamos que o consumo de dieta ocidental rica em gordura saturada e carboidrato simples durante 16 semanas causa hiperfagia, levando ao quadro de obesidade na idade adulta e prejuízo nas vias de sinalização dos hormônios insulina e grelina, que são importantes moduladores do metabolismo energético hepático, favorecendo o desenvolvimento de esteatose hepática não alcoólica. / Obesity is a major public health problem growing around the world, resulting from an imbalance between food intake and energy expenditure. Obesity is one of the main risk factor for developing the most prevalent chronic diseases as dyslipidemia, cardiovascular disease, type 2 diabetes and non-alcoholic fat liver disease, resulting in lower life expectancy and quality of life. Ghrelin is a hormone synthesized into the stomach, which has an important role in different tissues by a specific receptor (GHS-R1a), including the hypothalamus and peripheral tissues such as the liver. This hormone is involved in feeding behavior and adiposity by modulating storage or use of energy substrates in heart, skeletal muscle, adipocytes and liver. Moreover, Ghrelin is important in maintaining liver energy metabolism. These data support the hypothesis that ghrelin signaling pathways is a key component in the regulation of energy metabolism and hepatic glucose homeostasis. The aim of this study was to investigate the hepatic energy metabolism and signaling of ghrelin in obese adults Swiss mice fed the Western diet, rich in saturated fat and simple carboidrate. We analyzed the effect of this diet starting from 21 days of age (weaning) up to 133 days, using biometric and biochemical parameters, histomorphological assessment, high resolution respirometry, hepatic glycogen content and proteins content involved in insulin and ghrelin signaling besides the hepatic energy metabolism. Based on our results we found that the consumption of rich Western diet for 16 weeks promoves overeating leading to obesity in adulthood, metabolic desorders and impairment in signaling pathways of hormones insulin and ghrelin, which are important metabolic modulators of liver energy, contributing to the development of NAFLD.
22

Treinamento resistido melhora o controle cardiovascular e o perfil bioquímico de ratos expostos a uma dieta ocidental no período perinatal / Resistance training improves cardiovascular control and the biochemical profile of rats exposed to a Western diet in the perinatal per

Santana, Michael Nadson Santos 27 February 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The consumption of foods high in sodium and saturated fat but low in fiber in other essential nutrients is known as Western Diet and is directly associated with metabolic and autonomic changes and the emergence of cardiovascular disease. In addition, studies have shown that eating disorders such as lack or excess food in early life promotes structural and functional adaptations in the fetus culminating in the emergence of diseases in adulthood. The resistance training (RT) has been used as a non pharmacological therapy in the treatment of various diseases, including, cardiovascular, however, the effect of RT on the cardiovascular control mechanisms have not been fully explored. The present study investigated the effects of low intensity TR autonomic modulation and the biochemical profile of rats exposed to a Western diet during the perinatal period. Wistar rats received control diet or Western during pregnancy and lactation. The rats were divided into three groups: control (C), sedentary Western Diet (WS) and Western diet + TR (WTR). After 60 days, the animals began the protocol with TR 5 times a week for 4 weeks. After the animals were surgery to evaluate pulse interval variability and blood pressure, and baroreflex sensitivity (BRS). Blood samples were collected for biochemical analysis. The RT reduced mean arterial pressure (WTR= 108.2±3.7 vs WS= 121±2.5 mmHg, p <0.05), systolic arterial pressure (WTR= 135.2±3.1 vs WS= 151.5±3.4 mmHg, p <0.05), diastolic blood pressure (WTR= 89.1±2.8 vs 99.4±2.3 WS= mmHg, p <0.05). An increase in the BRS (WTR= 1.9±0.23 vs WS= 1.1±0.14 ms/mmHg, p <0.05). Furthermore, it was observed that the RT was able to reduce vascular sympathetic modulation when compared to the WS group (WTR= 5.48±1.033 vs WS= 8.25±1.018 mmHg2, p <0.05). Biochemical parameters, found difference in blood glucose (WTR= 116.2±4.6 vs WS= 153.8±6.3 mg/dL, p <0.05), total cholesterol (TC) (WTR= 67.0±3.8 vs WS= 85.6±3.4 mg/dL, p <0.05) and high (HDL) lipoproteins (WTR= 57.2±3.5 vs WS= 41.8±2.8 mg/dL, p <0.05) and low density lipoprotein (LDL) (WTR= 14.2±2.2 vs WS= 31.0±3.2 mg/dL, p <0.05). These results suggest that low-intensity TR promotes adaptations beneficial to the cardiovascular system, mediated by adjustments in the autonomic control mechanisms and improved biochemical profile of these animals. / O consumo de alimentos ricos em sódio e gordura saturada, mas pobre em fibras em outros nutrientes essenciais é conhecido como Dieta Ocidental e está diretamente associado a alterações metabólicas, autonômicas e o surgimento de doenças cardiovasculares. Além disso, estudos tem mostrado que distúrbios alimentares como a falta ou excesso de nutrientes no início da vida promove adaptações estruturais e funcionais no feto culminando no surgimento de doenças na fase adulta. O treinamento resistido (TR) vem sendo utilizado como terapia não farmacológica no tratamento de diversas doenças, dentre elas, as cardiovasculares, porém, o efeito do TR sobre os mecanismos de controle cardiovascular nao foram completamente explorados. O presente estudo investigou os efeitos do TR de baixa intensidade na modulação autonômica e no perfil bioquímico de ratos expostos a uma dieta ocidental durante o período perinatal. Ratas Wistar receberam dieta controle ou ocidental durante a gravidez e lactação. Os filhotes foram divididos em três grupos: Controle (C), Dieta ocidental sedentário (OCS) e dieta ocidental + TR (OCTR). Aos 60 dias de vida, os animais iniciaram o protocolo de TR realizado 5 vezes por semana durante 4 semanas. Ao fim, os animais foram cirurgiados para posterior registro da variabilidade do intervalo de pulso e da pressão arterial, bem como a sensibilidade do barorreflexo (SBR). Amostras de sangue foram coletadas para análise bioquímica. O TR reduziu a pressão arterial média (OCTR= 108,2±3,7 vs OCS= 121±2,5 mmHg, p<0,05), pressão arterial sistólica (OCTR= 135,2±3,1 vs OCS= 151,5±3,4 mmHg, p<0,05) e pressão arterial diastólica (OCTR= 89,1±2,8 vs OCS= 99,4±2,3 mmHg, p<0,05). Houve aumento na SBR (OCTR= 1,9±0,23 vs OCS= 1,1±0,14 ms/mmHg, p<0,05). Além disso, observou-se que o TR foi capaz de reduzir a modulação simpática vascular quando comparado ao grupo OCS (OCTR= 5,48±1,033 vs OCS= 8,25±1,018 mmHg2, p<0,05). Nos parâmetros bioquímicos, foi observada diferença na glicemia (OCTR= 116,2±4,6 vs OCS= 153,8±6,3 mg/dL, p<0,05), colesterol total (CT) (OCTR= 67,0±3,8 vs OCS= 85,6±3,4 mg/dL, p<0,05) e lipoproteínas de alta (HDL) (OCTR= 57,2±3,5 vs OCS= 41,8±2,8 mg/dL, p<0,05) e baixa densidade (LDL) (OCTR= 14,2±2,2 vs OCS= 31,0±3,2 mg/dL, p<0,05). Estes resultados sugerem que o TR de baixa intensidade promove adaptações benéficas ao sistema cardiovascular, mediadas por ajustes nos mecanismos de controle autonômico e melhora no perfil bioquímico destes animais.
23

Efeitos da derivação gástrica em Y de Roux e da gastrectomia vertical sobre o metabolismo lipídico hepático em ratos obesos / Roux-en-y gastric bypass is more effective than sleeve gastrectomy against hepatic steatosis, in western diet-obese rats

Morita, Fernanda Soares da Silva 25 August 2017 (has links)
Submitted by Edineia Teixeira (edineia.teixeira@unioeste.br) on 2018-02-27T12:47:21Z No. of bitstreams: 2 Fernanda_Morita2017.pdf: 1916527 bytes, checksum: d53cab0d448357d03f1447766ef5948a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-02-27T12:47:21Z (GMT). No. of bitstreams: 2 Fernanda_Morita2017.pdf: 1916527 bytes, checksum: d53cab0d448357d03f1447766ef5948a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-08-25 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Objective: Here, we compared the effects of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on fat liver deposition and expression of hepatic enzymes involved in hepatic de novo (DN) lipogenesis and β-oxidation, in western diet (WD)-obese rats. Background: Bariatric operations are known to improve non-alcoholic fatty liver disease (NAFLD), often found in obese humans. However, comparative studies on the efficacy of different bariatric procedures against NAFLD are scarce. Methods: At two months after WD consumption, the rats were divided into three groups: WD sham operation (WD-Sham), WD-RYGB and WD-SG. Three months after procedures, hepatic steatosis and lipid metabolism were verified. Results: After 3 months, body weight and abdominal fat mass were lower in WD-RYGB, compared with WD-SG rats. Both bariatric operations enhanced glucose tolerance and decreased triglycerides (TG) serum levels. However, total serum cholesterol (CHOL) as well as, hepatic TG and CHOL contents were reduced only in liver of WD-RYGB rats. Hepatic steatosis was corrected in 83% of the WD-RYGB rats, whereas microvesicular steatosis occurred in 100% of the WD-SG livers. Reduction in FASN protein content was observed in both WD-RYGB and WD-SG rats. However, reduced hepatic ACC and enhanced pACC/ACC and CPT-1a protein levels were observed only in WD-RYGB rats. Conclusions: NAFLD is more marked reduced in obese rats that underwent RYGB than SG procedures. This RYGB effect may be associated with decreased hepatic DN lipogenesis, associated with enhancement in β-oxidation, which reduced TG and CHOL content in the liver and serum of WD rats. / Introdução: As operações bariátricas são conhecidas por melhorar a doença hepática gordurosa não alcoólica (DHGNA), frequentemente encontrada em indivíduos obesos. No entanto, estudos que comparam a eficácia de diferentes procedimentos bariátricos sobre a DHGNA são escassos. Objetivo: Nesse trabalho, são comparados os efeitos da Derivação Gástrica em Y de Roux (DGYR) e da Gastrectomia Vertical (GV) sobre a esteatose hepática e sobre a expressão de enzimas envolvidas na lipogênese de novo e β-oxidação no fígado de ratos obesos pela dieta de cafeteria. Métodos: Dois meses após o consumo de dieta de cafeteria, os ratos foram divididos aleatoriamente em três grupos: cafeteria pseudo-cirúrgico (CAF-PC), cafeteria derivação gástrica em Y Roux (CAF-DGYR) e cafeteria gastrectomia vertical (CAF-GV). Três meses após os procedimentos cirúrgicos, a esteatose hepática e o metabolismo lipídico foram avaliados. Resultados: Três meses após os procedimentos operatórios, os animais CAF-DGYR apresentaram menor peso corporal e gordura abdominal em comparação com os ratos CAF-PC e CAF-GV. Ambas as operações bariátricas aumentaram a tolerância à glicose e diminuíram a concentração de triglicerídeos (TG) plasmáticos. No entanto, o colesterol total (COL), bem como as concentrações de TG e COL hepáticos, foram reduzidos apenas no fígado dos ratos CAF-DGYR. A esteatose hepática foi corrigida em 83% dos ratos CAF-DGYR, enquanto que os animais CAF-GV apresentaram 100% de esteatose microvesicular. Os ratos CAF-DGYR e CAF-GV apresentaram redução na expressão proteica da FASN. No entanto, apenas os animais CAF-DGYR tiveram redução da proteína ACC e aumento da razão da pACC/ACC e CPT-1a. Conclusões: A operação de DGYR foi mais eficaz na redução da DHGNA em ratos obesos, em comparação com a GV. Esse efeito da DGYR pode estar associado à diminuição da lipogênese hepática de novo, associado ao aumento da β-oxidação, que levou à redução das concentrações de TG e COL no plasma e no fígado de ratos obesos por dieta de cafeteria.
24

TARGETED AND NON-TARGETED METABOLITE ANALYSIS FOR DISEASE RISK ASSESSMENT: MEASURING BIOMARKERS OF SMOKE EXPOSURE AND HABITUAL DIET

Wellington, Nadine L January 2019 (has links)
Exposomics applies metabolomics methods and technologies to the comprehensive analysis of all low molecular weight molecules (< 1.5 kDa) in complex biological samples to characterize the interaction between cellular metabolism and exogenous lifestyle exposures that determine health and quality of life. To fully access the diverse classes of biological molecules related to an individual’s metabolic profile, metabolomics frequently requires the use of complementary analytical platforms, and employs targeted and untargeted molecular profiling strategies to identify biomarkers that are clinically relevant to an individual’s health status. Chapter 2 describes a quinoline-based boronic acid biosensor for N-acetylneuraminic acid that undergoes a striking binding enhancement under strongly acidic conditions. For the first time, this work allows for direct analysis of acidic sugars with high selectivity when using UV absorbance or fluorescence detection based on formation of a highly stable boronate ester complex with metabolites containing an α-hydroxycarboxylate moiety. Chapter 3 describes a targeted analysis of 24 different organic contaminants using GC-MS that can serve as biomarkers of recent smoke exposure following search-and-rescue training exercises by firefighters located at three different sites across the province of Ontario. Importantly, skin and possible respiratory uptake of various polycyclic aromatic hydrocarbons, methoxyphenols, and resin acids was confirmed by peak excretion of several wood smoke biomarkers in urine within 6 h following acute exposure. Chapter 4 applied a cross-platform metabolomics strategy based on CE-MS and GC-MS in order to identify and validate dietary biomarkers in matching plasma and urine samples collected from healthy participants in the pilot Diet and Gene Interaction Study (DIGEST). For the first time, we demonstrate that a panel of metabolites can serve as reliable biomarkers following contrasting Prudent and Western diets over 2 weeks of food provisions, which correlated well with self-reported diet records. This work paves the way for the development of objective biomarkers for accurate assessment of wood smoke exposures, as well as complex dietary patterns as required for new advances in occupational health and nutritional epidemiology. / Dissertation / Doctor of Philosophy (PhD) / Exposomics is an emerging multidisciplinary science aimed at deciphering the complex interactions that impact human health and gene expression, such as lifestyle choices (i.e., habitual diet) and lifelong environmental exposures. There is growing interest in identifying biomarkers that can be readily measured for chronic disease prevention given an alarming global prevalence of obesity and cardiometabolic disorders, including heart disease, type 2 diabetes and cancer. The research in this thesis focuses on developing new analytical methods for identifying and quantifying metabolites that may allow for better assessments of human health, and has contributed to the development of novel biosensors for the targeted analysis of N-acetylneuraminic (sialic) acid and related acidic sugars, as well as high resolution methods for broad spectrum analysis of biotransformed organic contaminants from smoke exposure by GC-MS, and plasma and urinary metabolites that differentiate contrasting Prudent and Western diets and correlate well with self-reported diet records.

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