• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 667
  • 313
  • 170
  • 76
  • 50
  • 50
  • 28
  • 16
  • 16
  • 10
  • 9
  • 6
  • 6
  • 6
  • 6
  • Tagged with
  • 1698
  • 739
  • 458
  • 388
  • 320
  • 282
  • 231
  • 206
  • 182
  • 150
  • 138
  • 128
  • 128
  • 128
  • 127
  • 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.
641

Avaliação do endotélio da córnea de chinchilas ( chinchilla Lanigera) em diferentes faixas etárias utilizando a microscopia especular

Bercht, Bernardo Stefano January 2012 (has links)
O endotélio é uma monocamada de células achatadas, poligonais e interligadas que recobrem a superfície posterior da córnea, sendo fundamental na manutenção da transparência desta estrutura. Embora as chinchilas (Chinchilla lanigera) sejam utilizadas em pesquisas oftálmicas, não existem dados referentes ao endotélio da córnea nesta espécie. Portanto, objetivou-se avaliar a densidade celular, a paquimetria, a área celular média e a morfologia do endotélio da córnea de chinchilas em diferentes faixas etárias. Foram estudados 60 bulbos oculares de 30 chinchilas, machos ou fêmeas, de diferentes faixas etárias. As chinchilas foram subdivididas em três grupos com 10 animais cada, designados por: G I (animais com idade entre dois a quatro meses); G II (animais com 11 meses de idade) e G III (animais com quatro anos de idade). A densidade celular endotelial média nos animais dos grupos G I, G II e G III foi de respectivamente 3385,39 ± 507,53, 2565,51 ± 220,46 e 1812,82 ± 117,92 células/mm2. A área celular média foi de respectivamente 301,51 ± 43,94, 392,46 ± 33,34 e de 553,79 ± 35,70 μm2 para G I, G II e G III. Os resultados apontam decréscimo da densidade, do pleomorfismo, e aumento da área celular média com o aumento da idade. A espessura da córnea aumentou em animais mais velhos. Conclui-se que o endotélio da córnea de chinchilas sofre alterações com o avanço da idade. / The corneal endothelium is a monolayer of interconnected flattened polygonal cells that cover the back surface of the cornea, it is essential for the maintenance of its transparency. Due to the complete lack of data on the endothelial cells of chinchilla (Chinchilla lanigera) and its possible use as an animal model in ophthalmic research, the objective was to evaluate the cellular density, pachymetry, the average cell area and morphology of the corneal endothelium of chinchillas in different age groups. It was studied 60 eyes of 30 chinchillas, male or female, of different ages. Chinchillas were divided into three groups with 10 animals each, designated by: G I (animals aged two to four months), G II (animals with 11 months) and G III (animals with four years of age). The mean endothelial cell density in the animals of G I, G II and G III were respectively 3385,39 ± 507,53, 2565,51 ± 220,46 and 1812,82 ± 117,92 cells/mm2. The average cell area was respectively 301,51 ± 43,94, 392,46 ± 33,34 and 553,79 ± 35,70 μm2 for GI, G II and G III. The results indicate a decrease in density, pleomorphism, and increased in average cell area with increasing age. Corneal thickness increased in older animals. The corneal endothelium of chinchillas changes with advancing age.
642

Avaliação das repercussões do transplante lamelar posterior sobre o endotélio corneano de suínos utilizando a microscopia eletrônica de varredura. Estudo in vitro

Albuquerque, Luciane de January 2014 (has links)
O transplante endotelial tem sido cada vez mais utilizado como uma alternativa ao transplante penetrante no tratamento das desordens do endotélio da córnea. No entanto, ao consultar a literatura não foram encontradas referências identificando em qual momento da cirurgia de transplante lamelar posterior ocorre maior dano às células endoteliais do botão doador. Objetivou-se avaliar e comparar as repercussões de duas etapas do transplante lamelar posterior sobre o endotélio da córnea de suínos utilizando a microscopia eletrônica de varredura. Utilizaram-se 30 bulbos oculares de 20 suínos, mestiços (1/2 Large White ½ Landrace), machos, com seis meses de idades e com peso médio de 100 kg. Foram designados dois grupos experimentais. No G1 constituído por 10 bulbos oculares, foi avaliado o dano ao endotélio da córnea após a confecção do botão doador. No G2, formado por 20 bulbos oculares, foi avaliado o dano ao endotélio da córnea após a inserção do botão doador no leito receptor utilizando introdutor de Busin. Perdas celulares ocorreram e variaram de acordo com o grupo estudado. A perda endotelial média do G1 foi 8,41% e no G2 17,31%. As diferenças foram estatisticamente significativas entre os grupos estudados. No presente estudo e nas condições experimentais realizadas foi possível concluir que a inserção do botão doador induziu maiores danos ao endotélio corneano de suínos, comparativamente à sua criação. / Endothelial keratoplasty has been adopted as an alternative to penetrating keratoplasty in the treatment of corneal endothelial disorders. However, references identifying at what time of posterior lamellar transplant surgery occurs greater damage to the endothelial cells of the donor button were not found, when consulting the literature. The aim of this study was to assess and compare the effects of two stages of posterior lamellar keratoplasty on the corneal endothelium of swine using scanning electron microscopy. A total of 30 eyes were evaluated in this study. The eyes were divided in two groups of ten each eye: G1 (evaluated after delamination and preparation of the donor button) and G2 (evaluated after delamination and preparation and insertion of the donor button using Busin glide). Cell loss occurred and varied according to the study group. The average endothelial cell loss was 8.41% in G1 and 17.31% in G2. The differences were statistically significant between the groups studied. Scanning electron microscopy demonstrated damage in either group. The average endothelial cell loss was 8.41% in G1 and 17.31% in G2. The differences were statistically significant between the groups studied. It was concluded in the present study and also in the experimental conditions that the insertion of the donor button has induced greater damage to the corneal endothelium of swine compared to its creation.
643

Apneia obstrutiva do sono e função endotelial em pacientes com hipertensão arterial resistente / Obstructive sleep apnea and endothelial function in patients with resistant hypertension

Nádia Maria Lopes Amorim 21 June 2013 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A apneia obstrutiva do sono (AOS) é considerada um fator de risco independente para as doenças cardiovasculares. Existem evidências de que indivíduos com apneia obstrutiva do sono podem apresentar elevação nos mediadores inflamatórios, alterações no perfil metabólico, aumento na atividade do sistema nervoso simpático, com consequente elevação da pressão arterial e disfunção endotelial. Nos últimos anos, inúmeros estudos tem apontado a AOS como um dos fatores responsáveis pela hipertensão resistente. O objetivo do estudo foi avaliar a presença da apneia obstrutiva do sono e o comportamento da função endotelial em pacientes com hipertensão resistente, comparando com hipertensos apresentando pressão arterial controlada com até 3 classes diferentes de fármacos anti-hipertensivos. Trata-se de um estudo transversal com 40 pacientes hipertensos: 20 com hipertensão arterial resistente (HAR) e 20 com pressão arterial controlada por medicação (hipertensão arterial controlada; HAC), sem distinção de raça ou gênero, com idade entre 18 e 75 anos. A pressão arterial casual e a monitorização ambulatorial da pressão arterial foram aferidas por método oscilométrico em aparelhos automáticos. A função endotelial e a presença da apneia obstrutiva do sono foram avaliadas através da tonometria arterial periférica pelos equipamentos Endo-PAT2000 e o aparelho portátil Watch-PAT200, respectivamente. A avaliação antropométrica foi realizada através das aferições das circunferências da cintura e do pescoço, índice de massa corporal (IMC), e relação cintura-estatura. A composição corporal foi avaliada por bioimpedância elétrica BIODYNAMICS 450. As análises estatísticas foram realizadas pelo software GraphPad PRISM, versão 6.01. A prevalência de AOS no grupo com HAR foi de 85% (Índice de apneia-hipopneia [AHI]= 12,391,89) e de 80% no grupo com HAC (AHI =20,744,69), sendo mais frequente em homens (p=0,04; OR=3,86; 95% IC 0,99 a 14,52). Os dois grupos apresentaram valores semelhantes das variáveis antropométricas avaliadas. A função endotelial avaliada pelo índice de hiperemia reativa foi similar nos dois grupos (grupo HAR: 1,880,09 vs. grupo HAC: 2,030,09; p=0,28). Apesar do número de dessaturações de oxigênio >4% ter apresentado diferença significativa entre os grupos (grupo HAR: 28,755,08 vs. grupo HAC: 64,1516,97; p=0,04), o tempo total de sono (grupo HAR: 309,515,27 vs. grupo HAC: 323,318,74 min) e a saturação mínima da oxi-hemoglobina (grupo HAR: 87,80,85 vs. grupo HAC: 83,32,37%) não mostraram essa diferença. Considerando todos os pacientes hipertensos, o AHI apresentou correlação significativa com o peso corporal (r=0,51; p=0,0007), o IMC (r=0,41; p=0,007), a circunferência da cintura (r=0,44; p=0,005), a circunferência do pescoço (r=0,38; p=0,01) e a relação cintura-estatura (r=0,39; p=0,01). Os pacientes sem AOS em comparação com os pacientes com AOS, apresentaram risco significativamente menor de apresentar comprometimento da função endotelial (OR=0,17; 95% IC 0,04-0,72; p=0,03). Os achados do presente estudo sugerem que a prevalência de AOS em pacientes com hipertensão resistente é elevada, porém semelhante a de indivíduos com hipertensão controlada. Pacientes com hipertensão resistente e controlada não apresentaram diferenças significativas em relação à função endotelial. A gravidade de AOS no grupo total de hipertensos se associou com maior risco de comprometimento da função endotelial. / Obstructive sleep apnea (OSA) is considered an independent risk factor for cardiovascular disease. There is evidence that individuals with OSA may have increased inflammatory mediators, changes in the metabolic profile, increased sympathetic activity with consequent elevation of blood pressure (BP) and endothelial dysfunction. Resistant hypertension (RH) is defined as uncontrolled blood pressure (BP ≥ 140/90mmHg) despite the current use of three hypotensive drugs at full doses, including a diuretic, or the need for >3 medications to control BP. OSA has been reported as the most common secondary cause of high blood pressure maintenance. The objective was to determine the prevalence of OSA and verify its association with endothelial function and anthropometric parameters in patients with resistant hypertension (RHGroup) and BP controlled by medication (CHGroup). It was a cross-sectional study involving 40 hypertensive patients (20 in RHG and 20 in CHG), aged between 18 and 75 years. Endothelial function and OSA were assessed by peripheral arterial tonometry. BP was measured by oscillometric method on automatic device. Endothelial function was assessed by peripheral arterial tonometry (PAT) by EndoPAT2000 and the OSA diagnosis also through PAT, using the portable device WatchPAT200. Anthropometric evaluation was performed through measurements of waist (WaC), hip and neck circumference (NC), BMI, waist to height ratio (WHtR), and body composition assessed by bioelectrical impedance. Patients were generally late middle-aged (54.95 2.39 in the RH group and 56.15 2.42 in the controlled hypertension [CH] group. The prevalence of OSA in RHG was 85% (17 of 20) [apnea-hypopnea index=12.391.89], and 80% (16 of 20) in CHG (AHI=20.744.69) and it was more frequent in men (93.7% [15 of 16] vs 75% [16 of 24]; p=0.04, OR=3.86; 95% IC 0.99 to 14.92). Both groups presented similar anthropometric parameters values. Endothelial function evaluated by reactive hyperemia index was similar in both groups (RHG: 1.880.09 vs CHG: 2.030.09; p=0.28). Although we found differences in oxygen desaturation> 4% (RHG: 28.75 5.08 vs CHG: 64.15 16.97, p = 0.04), total sleep time (RHG: 309.5 15.27 vs CHG: 323.3 18.74 min) and minimum saturation (RHG: 87.80.85 vs CHG: 83.32.37%) was not different. In general, OSA was correlated with weight (r = 0.51, p = 0.0007), BMI (r = 0.41, p = 0.0078), WaC (r = 0, 44, p = 0.005), NC (r = 0.38, p = 0.01) and WHtR (r = 0.39, p = 0.01) and independently associated with impairment of endothelial function (p = 0.0297, OR = 0.17, 95% CI 0.04 to 0.72). In conclusion, the findings of this study show high prevalence of OSA in patients with resistant hypertension, similar to that of controlled hypertension group. There were no significant differences in endothelial function between resistant and controlled hypertension patients. The presence of OSA in the total group of hypertensive patients was associated with increased risk of impaired endothelial function.
644

Efeito do tratamento com o extrato hidro-alcoólico do açaí (Euterpe oleracea Mart.) sobre as alterações cardiovasculares em ratos espontaneamente hipertensos (SHR) / Effect of the treatment with the hydroalcoholic extract of the açai seed (Euterpe oleracea Mart.) on cardiovascular changes in spontaneously hypertensive rats (SHR)

Viviane da Silva Cristino Cordeiro 28 February 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A hipertensão é uma das mais importantes causas de morte prematura no mundo. Estudos sobre a Euterpe oleracea Mart. (açaí), uma planta típica do Brasil e rica em polifenóis, têm mostrado grande potencial terapêutico contra a hipertensão, uma vez que seus benefícios podem ser associados às ações antioxidante, vasodilatadora e anti-hipertensiva. O rato espontaneamente hipertenso (SHR) é um modelo experimental utilizado para o estudo da hipertensão essencial. Neste estudo, investigamos o efeito do tratamento crônico do extrato hidroalcoólico do caroço de açaí (ASE) sobre a hipertensão de SHR. Animais SHR e Wistar receberam tratamento com ASE (200 mg/Kg/dia) na água de beber, ou veículo, desde 21 dias até 4 meses de idade e tiveram a pressão arterial sistólica (PAS) aferida por pletismografia de cauda. Os efeitos vasodilatadores da acetilcolina (ACh) e nitroglicerina (NG) foram estudados em leito arterial mesentérico (LAM) perfundido e pré-contraído com norepinefrina. A atividade das enzimas superóxido dismutase (SOD), catalase (CAT), glutationa peroxidase (GPx), os níveis de malondialdeído (MDA), a carbonilação de proteínas e os níveis de nitrito foram avaliados em plasma, LAM, coração e rim por espectrofotometria. A expressão das proteínas SOD e eNOS foram avaliadas por western blot em LAM e as alterações vasculares pela espessura da túnica média em aorta. A PAS foi maior (p<0.05) nos animais SHR, e reduzida pelo tratamento com ASE. O efeito vasodilatador reduzido da ACh em SHR foi recuperado pelo ASE e o da NG não foi diferente entre os grupos. Não houve diferença nos níveis de glicose e insulina em SHR comparados aos controles. Entretanto, a insulina se apresentou reduzida no grupo SHR+ASE. O nível de renina foi maior nos SHR e normalizado pelo ASE (p<0.05). Os níveis de MDA não foram diferentes entre SHR e controles, entretanto o tratamento com ASE reduziu esses níveis em rim de SHR (p<0.05). Os níveis de carbonilação de proteínas foram maiores em amostras de rim e coração de SHR e o ASE reduziu o dano sobre proteínas (p<0.05), não tendo diferença em plasma e LAM. A atividade da SOD foi menor em amostras de rim nos animais SHR e aumentada pelo tratamento com ASE (p<0.05). Entretanto, a atividade aumentada da SOD em coração e LAM dos SHR, foi reduzida pelo tratamento com ASE, não havendo diferença em amostras de plasma. Não houve diferença na atividade da GPx em amostras de LAM e coração dos diferentes grupos, porém sua atividade foi aumentada em rim dos SHR, e o tratamento com ASE normalizou essa atividade. Em plasma, a atividade da GPx foi reduzida em SHR e aumentada pelo tratamento (p<0.05). A atividade da enzima CAT foi reduzida em plasma e rim de SHR e o ASE aumentou sua atividade. Não houve diferença em amostras de LAM, entretanto em amostras de coração o tratamento aumentou a atividade da CAT em SHR (p<0.05). Em amostras de plasma, coração e rim, não houve diferença nos níveis de nitrito entre os diferentes grupos, porém em amostras de LAM foram menores em SHR e SHR+ASE (p<0.05). A expressão das proteínas eNOS e SOD apresentaram-se aumentadas em SHR (p<0.05) sem alteração com o tratamento. Os SHR apresentaram um aumento na espessura da camada média da aorta que foi reduzido (p<0.05) pelo ASE. Este estudo demonstrou que o tratamento crônico com ASE em SHR reduziu a hipertensão, preveniu a disfunção endotelial e o remodelamento vascular. O aumento da defesa antioxidante e redução do dano oxidativo devem contribuir para os efeitos benéficos de ASE. Portanto, sugerimos que o ASE pode ser uma ferramenta importante para o tratamento das alterações cardiovasculares associadas à hipertensão essencial. / Hypertension is a major cause of premature death worldwide. Studies on the Euterpe oleracea Mart. (açaí), a typical plant of Brazil, rich in polyphenols, have shown great therapeutic potential against hypertension, since its benefits can be associated with antioxidant action, vasodilator and antihypertensive. The spontaneously hypertensive rat (SHR) is an experimental model used for the study of essential hypertension. Therefore, this study investigated the effect of chronic treatment of hydroalcoholic extract of stone of the açaí (ASE) on hypertension in SHR. For this purpose, SHR and Wistar rats were treated with ASE (200 mg.kg-1.day-) in drinking water, or vehicle, from 21 days to 4 months of age and had their systolic blood pressure (SBP) measured by tail plethysmography. The vasodilatory effects of acetylcholine (ACh) and nitroglycerin (NG) were studied in perfused mesenteric arterial bed (LAM) pre-contracted with norepinephrine. The activity of the enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), levels of malondialdehyde (MDA), protein carbonylation and nitrite were evaluated in plasma, LAM, heart and kidney by spectrophotometry. The expression of eNOS and SOD protein were evaluated by western blot and vascular changes by the thickness of the tunica media in aorta. SBP was higher (p <0.05) in SHR, and reduced by treatment with ASE. The reduced vasodilator effect of ACh in SHR was recovered by ASE and of the NG was not different between groups. There was no difference in the levels of glucose and insulin in SHR compared to controls. However, insulin was reduced in the SHR+ASE group. The level of renin was higher in SHR and normalized by the ASE (p <0.05). MDA levels were not different between SHR and controls, however treatment with ASE reduced these levels in kidney samples of SHR (p <0.05). The levels of protein carbonylation were higher in samples of kidney and heart of SHR and the protein damage was reduced by treatment with ASE (p <0.05), with no difference in plasma samples and LAM. The SOD activity was lower in samples of kidney in SHR and increased by treatment with ASE (p <0.05). However, the increased activity of SOD in samples of heart and LAM of SHR was reduced by treatment with ASE, with no difference in plasma. There was no difference in GPx activity in samples of LAM and hearts of different groups, but its activity was increased in kidney of SHR, and ASE treatment normalized this activity. In plasma GPx activity was reduced in SHR and increased by treatment (p <0.05). The CAT enzyme activity was reduced in samples of plasma and kidney of SHR and ASE increased its activity. There was no difference in samples of LAM, but in samples of heart treatment increased the activity of CAT in SHR (p <0.05). In plasma samples, heart and kidney, there was no difference in nitrite levels between different groups, but it was reduced in samples of LAM of SHR and SHR+ASE (p <0.05). The expression of eNOS and SOD protein was increased in SHR (p <0.05) and unchanged by treatment. The SHR exhibited an increase in medial thickness of the aorta which was reduced (p <0.05) by ASE. This study showed that chronic treatment with ASE reduced hypertension in the SHR and prevented the endothelial dysfunction and vascular remodeling. The increase in antioxidant defense and reduction of oxidative damage may contribute to the beneficial effects of ASE. Therefore, we suggest that the ASE can be an important tool for the treatment of cardiovascular disorders associated with essential hypertension.
645

Circulating microvesicles : responses to exercise and heat stress, and their impact upon human endothelial cells

Wilhelm Neto, Eurico Nestor January 2016 (has links)
Cell-derived microvesicles (MVs) are naturally released into the human circulation and an increase in the concentration of certain MV populations have been observed after exercise. However, the MV appearance dynamics, the exercise-related stimuli that induce their formation and physiological relevance are poorly understood. Hence, the overall objectives of this thesis were to: 1) characterise the circulating platelet (PMV) and endothelial-derived MVs (EMVs) responses during exercise and recovery, as well as their arteriovenous dynamics, 2) investigate the potential role of haemodynamic forces on MVs formation in vivo by vascular shear stress manipulations, and 3) explore the putative proliferative, chemotactic and angiogenic potential of exercise-derived MVs upon human vascular endothelial cells in vitro. Chapter 5 of this thesis describes the time-course of MV appearance in response to prolonged cycling, and demonstrates that intravascular [PMV] increases during and after exercise performed in the heavy intensity domain, whereas [EMV] remains unaltered. Moreover, [PMV] during exercise was related to estimates of vascular shear stress and plasma noradrenaline levels. Results from chapter 6 revealed that PMVs increased in the arterial circulation during passive heat stress, and in the arterial as well as venous circulation during short duration very heavy exercise engaging either a large or small muscle mass. The increases in [PMV] were not directly linked to local changes in vascular shear stress through heat stress and exercise, indicating a systemic PMV response. Finally, chapter 7 revealed that exercise-derived MVs supported endothelial proliferation and migration, while displaying pro-angiogenic potential in vitro. In conclusion, results of this thesis provide original information about MV dynamics, by demonstrating that PMV increase systemically in the circulation not only after but during exercise involving a small and large muscle mass. This MV response seems to be modulated by exercise intensity, and is only partially linked to levels of vascular shear stress. Moreover, circulating MVs produced during exercise present stimulatory angiogenic and mitogenic effects upon endothelial cells in vitro, suggesting a novel potential link between vascular adaptation and exercise training.
646

Efeitos do estradiol 17beta oral baixa dose e drospirenona ou não oral associado à progesterona sobre variáveis relacionadas com função endotelial, inflamação e perfil metabólico em pacientes pós-menopausa recente

Casanova, Gislaine Krolow January 2007 (has links)
A relação entre risco cardiovascular e terapia hormonal na pós-menopausa é controversa. Ainda que o estrogênio endógeno possa estar associado ao menor risco cardiovascular observado em mulheres na pré-menopausa em relação às pós-menopáusicas, grandes ensaios clínicos, como o WHI, falharam em demonstrar efeito benéfico da terapia hormonal. Estes resultados podem ter sido influenciados por uma série de fatores, sendo os mais importantes: idade média das pacientes e tempo de menopausa superiores às candidatas usuais de terapia hormonal, tipo e dose dos hormônios utilizados. Desenvolvemos ensaio clínico randomizado, cross-over, com objetivo de avaliar os efeitos de dois tipos de tratamento hormonal na menopausa: tratamento oral baixa dose, associação de estradiol 17 β nasal 300 μcg e drospirenona 2 mg, diário e tratamento nâo oral, estradiol 17 β nasal diário e progesterona micronizada vaginal, 200 mg, 14 dias por mês , sobre variáveis relacionadas com inflamação e função endotelial, perfil antropométrico, metabólico e hormonal em mulheres na pós-menopausa recente e sem doença clínica evidente. Quarenta mulheres na pós-menopausa foram alocadas aleatoriamente para iniciar o tratamento hormonal por um dos dois grupos de tratamento: via oral baixa dose (n=20): ou via não oral (n=20). Ao final dos primeiros 2 meses do estudo, o grupo inicialmente tratado com terapia oral passou a receber tratamento não oral por mais 2 meses, e o grupo inicialmente tratado com terapia não oral passou a receber terapia oral também por mais 2 meses. A avaliação laboratorial foi realizada antes e ao final de 2 e 4 meses de tratamento hormonal. A amostra do estudo foi composta por mulheres com média etária de 51,2 ± 2,7 anos e tempo de amenorréia de 23,1 ± 10 meses. Após os primeiros 2 meses de tratamento, não houve diferença significativa entre os tratamentos sobre circunferência da cintura, relação cintura/quadril, índice de massa corporal e níveis de pressão arterial. Colesterol total diminuiu em ambos os tratamentos de forma semelhante. O tratamento oral teve um efeito maior em reduzir os níveis de LDL-C. HDL-C, triglicerídeos, glicemia e insulinemia de jejum, glicemia e insulinemia 2 horas após sobrecarga oral de glicose não se modificaram. PCR e FVWdiminuíram significativamente, e fibrinogênio permaneceu inalterado. Após o período de 4 meses de tratamento hormonal, não houve diferença significativa entre os tratamentos sobre circunferência da cintura, relação cintura/quadril, índice de massa corporal e níveis de pressão arterial. Durante o tratamento oral observou-se redução da circunferência da cintura e da relação cintura/ quadril em relação ao basal. Colesterol total diminuiu em ambos os grupos de tratamento, e HDL-C diminuiu discreta, mas significativamente após o tratamento oral, enquanto triglicerídeos diminuíram durante tratamento não oral. A glicemia 2 horas após sobrecarga oral de glicose apresentou valores mais elevados em relação ao basal após tratamento oral. Em contraste, glicemia e insulinemia em jejum e insulinemia 2 horas após sobrecarga oral de glicose não se modificaram. Níveis de FVW encontraram-se significativamente reduzidos após 4 meses de tratamento hormonal. Em conclusão, os resultados obtidos em nosso estudo sugerem que os tratamentos não induziram efeitos deletérios sobre variáveis relacionadas com risco cardiovascular, a curto prazo, em uma população de mulheres na pós-menopausa recente e aparentemente saudáveis. O tratamento hormonal baixa dose por via oral manteve os efeitos benéficos conhecidos do tratamento hormonal por via oral, a redução do colesterol total e do LDL-C, e evitou os efeitos nocivos tradicionalmente atribuídos à via oral: o aumento de marcadores próinflamatórios, relacionados à disfunção endotelial. O tratamento hormonal por via não oral mostrou-se também uma alternativa segura, não relacionado à modificações no perfil metabólico e nos marcadores de função endotelial. / The relationship between cardiovascular risk and hormone therapy (HT) for menopause is a contemporary and complex issue. While evidences suggest an association between endogenous estrogen and cardiovascular protection among premenopausal women, recent clinical trials have failed in demonstrate a benefic impact of HT on prevention of cardiovascular events. These results seem to be related by several factors, including selection biases like higher mean age of and time since menopause of participants, fixed type and dosages of hormones administered. A cross-over, randomized clinical trial was designed in order to evaluate the effects of two types of HT: low dose oral treatment, estradiol 17 β oral 1 mg and drospirenona 2 mg, by day and non-oral treatment, estradiol 17 β nasal 300 μcg by day and vaginal micronized progesterone, 200 mg/d, 14 days by month on variables associated with endothelial function, anthropometric, metabolic and hormonal variables on early and healthy postmenopausal women.Forty postmenopausal women were randomly allocated to start with one of the treatments: low dose oral treatment or non-oral treatment. At the end of two months, the group that started with low dose oral treatment passed to receive the non oral treatment for additional two months and vice-versa. Laboratory evaluations were performed before, at 1, 2 and 4 months of HT. The sample of the study included postmenopausal women presenting mean age of 51.2 ± 2.7 years and mean time since menopause of 23.1 ± 10 months. After 2 months, no significant differences were observed between treatments on waist circumference, waist to hip ratio, BMI and arterial pressure. Total cholesterol levels were reduced on both treatments. Low oral dose treatment had greater effect in reducing LDL cholesterol. HDL cholesterol, triglycerides, fast and 2 hours glucose and insulin levels did not change with either treatment. PCR and vW factor levels were reduced in both treatment groups and fibrinogen did not change. After 4 months of low oral dose treatment, a reduction on waist circumference and waist/circumference ratio was found. Total cholesterol was lower than basal levels on bothtreatment groups and while HDL cholesterol presented a slight but significant reduction on low oral dose treatment, triglycerides decreased significantly on non oral treatment. Two hours glucose was higher than basal levels but fast glucose and fast or 2 h insulin levels did not change after low oral dose therapy. After 4 months, vW factor decreased only on non oral treatment and PCR and fibrinogens were unchanged on both treatment groups. In conclusion, the present results suggest that the studied treatments did not induce deleterious effects on variables related to cardiovascular risk, at least at short period of time, in early postmenopausal and apparently healthy women. Low dose oral HT has maintained the well known beneficial effects on lipid profile (lower total and LDL cholesterol) and did not induced an increase on pro-inflammatory or endothelial function markers. On the other hand, non oral HT has shown to be a safe alternative, and was not related to changes on metabolic profile or markers of endothelial function.
647

Avaliação da função endotelial em pacientes com diabetes mellitus tipo1 através da dilatação arterial mediada por fluxo : associações com o tempo de diabetes e o controle glicêmico / Endothelial dysfunction occurs in type 1 diabetes adolescents under 5 years of disease and is associated to microalbuminuria and long-term glycemic control

Cé, Gislaine Vissoky January 2009 (has links)
O Diabetes Mellitus tipo 1 (DM1) está associado a uma incidência aumentada de doença micro e macrovascular. Estudos sugerem que a doença vascular no DM1 tenha como evento precursor a disfunção endotelial (DE). A hiperglicemia parece causar DE no DM1 através da geração do estresse oxidativo. O momento exato do surgimento da DE na história natural do DM1, assim como a influência do controle glicêmico de curto e longo prazo ainda não estão estabelecidos. Objetivo: O objetivo principal do presente estudo foi avaliar a função endotelial através da Dilatação Arterial Mediada por Fluxo (DMF) em indivíduos com Diabetes Mellitus tipo1. Os objetivos secundários foram analisar os fatores que possam estar envolvidos com a disfunção endotelial no DM1, como o tempo de diabetes, o controle glicêmico e a presença de complicações microvasculares, como a microalbuminúria. Métodos: Estudo prospectivo transversal com 57 pacientes com DM1 e 10 indivíduos não diabéticos, consecutivamente alocados e comparados quanto à presença de DE, através da DMF, aferida pela dilatação da artéria braquial após hiperemia reativa (dilatação endotélio-dependente) e após dilatação mediada por uso de nitrato sublingual (dilatação endotélio-independente). Considerou-se como DE quando valores de DMF foram menores ou iguais a 8% em relação ao valor basal. Os pacientes foram orientados a fazer monitorização glicêmica capilar intensiva nos 30 dias que antecederam a avaliação vascular. No 30º dia, houve coleta de exames laboratoriais e a avaliação vascular foi realizada. Dados prospectivos e históricos de hemoglobina glicosilada (HbA1c), através da técnica de imunoturbidimetria (Cobas Integra 400; Roche), foram obtidos aos 3, 6, 9,12,15,18 e 24 meses anteriores ao teste para DMF. Os critérios de exclusão foram: tabagismo, hipertensão, obesidade, hipotireoidismo, uso de estatina, gestação, história de neoplasia ou doença vascular. Resultados: Em 57 pacientes com DM1 estudados, 28 (49%) apresentaram DE. A média da dilatação endotélio-dependente foi significativamente menor nos pacientes com DM1, comparados aos indivíduos não-diabéticos (9,48±6,48% vs.14,56±5,60%, p=0,02). A dilatação endotélio-independente foi significativamente menor nos pacientes com DM1 em relação aos controles (22,26±9,2% vs. 29,31±4,2%, p=0,02, VR: acima de 8%), mas não houve diferença entre os DM1 com ou sem DE (p= 0,72). O tempo de DM1 (meses) foi maior nos pacientes com DE do que nos sem DE (105,4±74,7 vs. 66,3±48,0, p=0.02) e houve correlação linear negativa entre duração do DM e presença de DE (r-0,28, p=0,02). A média da HbA1c (%) coletada no momento da avaliação vascular foi semelhante entre pacientes com DM1 com DE e sem DE (8,97%±1.85 vs 8,23%±1.45, p=0.10) e não houve correlação significativa com a DMF (r=-0,128 p=0,34). Todavia, quando as HbA1c históricas foram avaliadas, houve correlação significativa com a HbA1c aos 15 meses (r=-0,303, p=0,02) e no período de 12-24 meses anteriores ao exame vascular (r=-0,289, p=0,03), mas não com a HbA1c média de 0-12m (r=-0,181 p=0,18). A DMF foi menor nos pacientes com microalbuminúria em relação aos normoalbuminúrcos (4,83±3,81% vs 10,35±6,50%, p=0,015). A microalbuminúria também foi mais prevalente nos DM1 com DE do que sem DE (22,2% vs 3,5%, p=0,04). Considerando apenas os pacientes com DM1 com tempo de DM menor que 5 anos, 10/28 (35,7%) apresentaram DE. Com relação a dilatação não-dependente de endotélio (%), não houve diferença em relação aos controles (p=0,16) e nem entre os DM1 com e sem DE (p=0,27). A média da HbA1c na época do exame vascular também não foi diferente nos pacientes com e sem DE (8,20±0,94% vs. 7,99±1,37%, p=0,66). As correlações de Pearson entre a DMF e as HbA1c históricas foram negativas aos 12 meses (r=-0,419, p=0,03), aos 15 meses (r=-0,437, p=0,03) e com a HbA1c média de12-24 meses (r=-0,426, p=0,027). Conclusões: Pacientes com DM1 apresentam prejuízo na função endotelial, quando comparados a controles não diabéticos. A DE é um evento precoce na história natural do DM1, e está presente nos pacientes antes dos 5 anos de doença, estando associada, ao tempo de DM1, à presença de microalbuminúria e ao controle metabólico de longo-prazo. A ausência de disfunção de músculo liso endotelial no grupo com menos de 5 anos de DM, com valores de dilatação não-endotéliodependente semelhantes aos controles, sugere ser a DE um fenômeno ainda reversível nos primeiros anos de doença. / Patients with Type 1 diabetes (T1DM) are at high-risk for developing micro and macrovascular complications. Endothelial dysfunction (ED) has been suggested to be a precursor of both complications in Type 1 diabetes. Hyperglycemia may be associated to ED through generation of oxidative stress. The exactly moment when ED occurs in T1DM is until not well established. Also we do not known if long-term rather than short term metabolic control have a greater impact in ED. Objective: The aim of this study was to assess endothelial function by Flow Mediated Dilation (FMD) in (T1DM) patients and compare with non- diabetic controls. Secondary objectives were to analyze factors that could be associated to ED: duration of T1DM, glycemic control and microvascular complications like microalbuminuria. Research design and methods: In a cross-sectional study 57 adolescents with T1DM and 10 non-diabetic controls, were recruited and compared for the presence of ED by FMD with evaluation of reactive hyperemia (endothelium-dependent dilatation) and after using sublingual nitrate spray for assessed non-endothelialdependent dilatation. ED was considered when FMD ≤ 8% in relation to basal value. Patients performed intensive self monitoring blood glucose for 30 days before vascular studies. At day 30, blood was drawn for biochemical determinations and endothelial function was carried out. Historical data from Glycated hemoglobin (HbA1c), determined by immunoturbidimetry (Cobas Integra 400; Roche) were collected at 3, 6, 9,12,15,18 and 24 months before the test for FMD. Excluding criteria were any time tobacco use, clinical hypertension, obesity, hypothyroidism, statin use, current pregnancy and any history of previous neoplasia or vascular disease. Results: Of 57 T1DM patients studied, 28 (49%) presented ED. FMD was significantly decreased in T1DM compared to controls (9.48±6.48% vs. 14.56±5.60%, p=0.02). Nitrate-mediated dilation (%) was decreased in T1DM compared to controls (22.26±9.2% vs. 29.31±4.2%, p=0.02, RV= >8%), but it was not different between T1DM with or without ED (p=0.72). The duration of T1DM was longer in ED vs. Non- ED patients: 105.4±74.7 vs. 66.3±48.0 months, p= 0.02 and presented negative linear correlation between duration of T1DM and FMD (r=-0.284, p=0.03). HbA1c at the moment of the vascular analysis did not differ between ED and Non-ED patients (8.97±1.85% vs. 8.23±1.44%, p= 0.10) and it was not associated with FMD (r=-0.128, p=0.34). However, we found significant negative correlation between HbA1c and FMD at 15 months (r=-0.303, p=0.02) and at 12-24 months before vascular study, but not with median HbA1c of 0-12m (r=-0.181 p=0.8). Microalbuminuria was more prevalent in T1DM patients with ED than Non-ED (22.2% vs. 3.5%, p=0.04). FMD was decreased in microalbuminuric compared to normoalbuminuric patients (4.83±3.81% vs 10.35±6.50%, p=0.015). In T1DM patients with less than 5 years of disease, 10 of 28 (35.7%) presented ED. Nitrate-mediated dilation, in this group, was not decreased compared to controls (p=0.16) and it was not different in T1DM patients with or without ED (p=0.27). HbA1c at the moment of vascular analysis did not significantly differ in ED compared to Non-ED patients (8.20±0.94% vs.7.99±1.37%, p=0.66). Pearson’s correlation between FMD and historical HbA1c was negative with HbA1c at 12 (r=-0.419, p=0.03), at 15 (r=-0.437, p=0.03) and 12-24 months before vascular analysis (r=- 0.426, p=0.02). Conclusions: Endothelial function is impaired in T1DM patients compared to nondiabetic controls. ED is a phenomenon that can occur quite early in the natural history of T1DM, presented before 5 years of disease and is related to duration of disease, long- term metabolic control and microalbuminúria. Vascular smooth muscle was not impaired in T1DM patients with less than 5 years of disease, with values of non-endothelial-dependent dilation similar to controls, suggesting that ED can be a reversible event in this first years of disease.
648

Effects of Muscle Contraction Frequency on Blood Glucose Control, Insulin Sensitivity, Endothelial Function and Blood Pressure Among Obese Males

January 2017 (has links)
abstract: Cardiovascular disease and diabetes are major health burdens. Diabetes is a primary risk factor of cardiovascular disease, and there is a strong link between obesity and risk of developing diabetes. With the prevalence of prediabetes highest among overweight/obese individuals, investigation into preventative strategies are needed. Aerobic exercise is a potent stimulus for both insulin and non-insulin dependent glucose uptake into the skeletal muscle. A single exercise session can improve insulin sensitivity within hours after exercise. The effects of intensity, type, and volume of exercise on glucose homeostasis have been studied extensively; however, controlling for muscle contraction frequency with a constant exercise intensity and workload has not been examined. The purpose of this study was to compare muscle contraction frequency during aerobic exercise by altering cycling cadence on insulin sensitivity and vascular health. Eleven obese males (age=28yr, BMI=35kg/m2) completed three conditions in random order: 1) control-no exercise; 2) 45-min cycling at 45 revolutions per minute (45RPM) at 65-75%VO2max; 3) 45-min cycling at 90RPM at 65-75%VO2max. Glucose control and insulin sensitivity were assessed with oral glucose tolerance tests (OGTT) 4 hours post-exercise. Vascular health was assessed via flow-mediated dilation (FMD) pre-exercise, 1-hr and 2-hr post exercise and ambulatory blood pressure was assessed pre-exercise, and continually every 15 min post-exercise. Linear mixed models were used to compare the mean differences in outcome variables. There were no significant differences found between control and both exercise conditions for all OGTT outcomes and no differences were found between control and exercise in FMD (all, p>0.05). Significant effects for exercise were found for both brachial and central blood pressure measures. Brachial systolic blood pressures were lower at 2- and 4-hr post-exercise by approximately -10 and -8mmHg, respectively (p<0.001 and p=0.004) versus control. Central systolic blood pressures were lower at 2-, 3-, and 4-hr post-exercise by approximately -8, -9 and -6mmHg, respectively (p<0.001, p=0.021 and p=0.004) versus control. In conclusion, aerobic exercise, regardless of muscle contraction frequency, were unable to effect glucose control and insulin sensitivity. Similarly, there was no effect on vascular function. However, there was a significant effect of aerobic exercise on reducing post-exercise blood pressure. / Dissertation/Thesis / Doctoral Dissertation Exercise and Nutritional Sciences 2017
649

Oxidative Stress and a High Fat Diet in Rats: An Intervention Study on the Effects of an Organometallic Compound on Enzyme Function, Inflammatory Markers, Endotoxins and Fasting Serum Glucose and Insulin Levels

January 2018 (has links)
abstract: Cardiovascular disease has reached epidemic proportions resulting in its ranking as the number one cause of mortality in the Western world. A key player in the pathophysiology of vascular disease is oxidative stress due to free radical accumulation. This intervention study was conducted to evaluate any potential mediation of oxidative stress using a soil-derived organometallic compound (OMC) with suspected antioxidant properties. A 10-week study was conducted in male Sprague-Dawley rats (n = 42) fed either a high-fat diet (HFD) consisting of 60% kcal from fat or a standard Chow diet containing only 6% kcals from fat. Rats from each diet group were then subdivided into 3 subgroups (n = 6-10 each) that received 0.0 mg/mL, 0.6 mg/mL or 3.0 mg/mL OMC. Neither the diet nor OMC significantly changed protein expression of inducible nitric oxide synthase (iNOS) in isolated aortas. Plasma levels of the inflammatory marker, tumor necrosis factor alpha (TNFα) were below detection after the 10-week trial. Superoxide dismutase (SOD), a scavenger of the free radical, superoxide, was not significantly different following HFD although levels of SOD were significantly higher in Chow rats treated with 0.6 mg/mL OMC compared to HFD rats treated with the same dose (p < 0.05). Lipopolysaccharides (LPS) were significantly increased following 10 weeks of high fat intake (p < 0.05). This increase in endotoxicity was prevented by the high dose of OMC. HFD significantly increased fasting serum glucose levels at both 6 weeks (p < 0.001) and 10 weeks (p < 0.025) compared to Chow controls. The high dose of OMC significantly prevented the hyperglycemic effects of the HFD in rats at 10 weeks (p = 0.021). HFD-fed rats developed hyperinsulinemia after 10 weeks of feeding (p = 0.009), which was not prevented by OMC. The results of this study indicate that OMC may be an effective strategy to help manage diet-induced hyperglycemia and endotoxemia. However, further research is needed to determine the mechanism by which OMC helps prevent hyperglycemia as measures of inflammation (TNFα) and vascular damage (iNOS) were inconclusive. / Dissertation/Thesis / Masters Thesis Nutrition 2018
650

Influência da intensidade do exercício físico na função endotelial de pacientes com insuficiência cardíaca / Influence of intensity of exercise on endothelial function in patients with heart failure

Netto, Almir Schmitt 10 June 2015 (has links)
Made available in DSpace on 2016-12-06T17:07:03Z (GMT). No. of bitstreams: 1 Resumo Almir Schmitt Netto.pdf: 90600 bytes, checksum: 0ff2c9f9fdf2050ef431ab5a5dee8dca (MD5) Previous issue date: 2015-06-10 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Background: It is clear in the literature that physical exercise promotes reduction of symptoms caused by heart failure (HF). However there are differences about the best training intensity to be applied. In this respect, little has been studied about endothelial function and high intensity exercise. Aim: To evaluate the effect of high-intensity interval training in endothelial function, physical fitness, oxidative stress, lipid profile and quality of life in patients with HF. Method: Randomized controlled clinical trial, developed for 12 weeks, with nineteen male patients diagnosed with compensated heart failure, lower ejection fraction &#8804; 45%, mean age 53.8±8.0 years, NYHA class II and III , randomly distributed in two groups: group submitted to moderate intensity exercise (MIE), exercising with heart rate (HR) corresponding to the aerobic threshold and high intensity interval exercise group (HIIG), performing in the HR corresponding to the anaerobic threshold. Both groups were submitted to an aerobic exercise on a treadmill three times a week for 60 minutes. The evaluations were performed before and after the training. Assessments of endothelial function were performed using Doppler; cardiorespiratory performance by cardiopulmonary exercise test; activity of superoxide dismutase (SOD) and the levels of small and large Low-density (sd-LDL) were measured by spectrophotometry and the quality of life (QoL) by Minnesota Living with Heart Failure Questionnaire (MLHFQ). Results: Endothelial function showed significant improvement only in MIE(p=0:03); VO2max obtained significant increase in HIIG (p<0.001); significant increases were observed in SOD activity in HIIG (p<0.005); plasma levels of sd-LDL have a significant decrease in MIE (p<0.005) and QoL parameters were significantly improved in all domains and in both intensities. Conclusion: Both training showed particularities in relation to its results. Being that HIIG improved aspects related to cardiorespiratory fitness and oxidative stress control, while the MIE to endothelial function, and both groups had significant improvement. / Fundamentação: É consenso que o exercício físico promove redução dos sintomas causados pela insuficiência cardíaca (IC). Entretanto existem divergências quanto a melhor intensidade do treinamento a ser aplicada. Neste contexto, pouco tem sido estudado sobre a função endotelial em intensidades superiores. Objetivo: Investigar o efeito do exercício intervalado de alta intensidade sobre a função endotelial, aptidão física, estresse oxidativo, perfil lipídico e qualidade de vida em pacientes com IC. Método: Ensaio clínico controlado randomizado, desenvolvido durante 12 semanas, com dezenove pacientes homens diagnosticados com IC compensados, fração de ejeção menor que 45%, média de idade de 53,8±8 anos, classe II e III da NYHA, aleatoriamente distribuídos em dois grupos: grupo submetido a exercício de moderada intensidade (GMI), exercitando-se com frequência cardíaca (FC) correspondente ao limiar aeróbio e grupo de exercício intervalado de alta intensidade (GAI), exercitando-se com FC correspondente ao limiar anaeróbio. Ambos os grupos realizaram exercício aeróbio em esteira rolante, três vezes por semana, durante 60 minutos de sessão de exercício. As avaliações foram realizadas no incio e após o período de treinamento. As avaliações da função endotelial foram realizadas por meio do ecodoppler; desempenho cardiorrespiratório por meio da ergoespirometria (VO2pico); atividade da superoxido dismutase (SOD) e os níveis de smal and large Low-density (sd-LDL) foram medidas através de espectrofotometria e a qualidade de vida (QV) com o Questionário de Minesotta. Resultados: A função endotelial apresentou melhora significativo apenas no GMI (p=0.03); o VO2max obteve aumento significativo no GAI (p<0.001); foram observados aumento significativo na atividade da SOD no GAI (p<0.005); os níveis plasmáticos de sd-LDL tiveram diminuição significativa no GMI (p<0.005) e os parâmetros de QV obtiveram melhora significativa em todos os domínios e em ambas as intensidades. Conclusão: Ambos os treinamentos apresentaram particularidades em relação aos seus resultados. A função endotelial apresentou melhora aumento significatido em ambos os grupos, sendo que o GAI melhorou os aspectos relacionados à aptidão cardiorrespiratória e controle do estresse oxidativo.

Page generated in 0.0608 seconds