No description available.

No description available.

A decrease in the apparent diffusion coefficient (ADC) of water is becoming an important tool for the detection of acute and chronic brain disorders, yet it is not known whether changes in myocardial ADCs hold similar potential. Consequently, this work determined whether the ADCs of water or intracellular metabolites could be used to show ischaemia or cell swelling in the isolated rat heart. A modified STEAM pulse sequence was designed to measure the ADCs of the ¹H-NMR detectable metabolites, taurine and creatine, with 4 min time resolution in a 3 mm myocardial slice. Experiments included the measurement of: a) metabolite diffusion coefficients and diffusion tensors in solutions, and ADCs and diffusion tensors in the isolated, KCl-arrested rat heart; b) taurine and creatine content during 32 min total, global ischaemia in the isolated rat heart; c) metabolite and water ADCs before, during and after ischaemia; and d) changes in average cardiomyocyte diameter during perfusion and ischaemia using the taurine ADC measurements. At a diffusion time of 50 ms, the myocardial ADCs were 1.06 x 10^-3 mm²/s for water, 0.29 x 10^-3 mm²/s for taurine and 0.26 x 10"3 mm 2 /s for creatine. Neither taurine nor creatine was lost from the heart during ischaemia, making either suitable for ischaemic diffusion measurements. Contrary to changes in the brain, myocardial water and taurine ADCs remained constant during ischaemia; however, the total creatine ADC increased by 35% which was shown to result from hydrolysis of PCr to creatine. Using the taurine ADC measurements at diffusion times between 50 ms and 1510 ms, the average myocyte diameter was calculated to be 40 μm during perfusion and 27 μm by the end of ischaemia. The decrease in myocyte diameter indicates that the buffer perfused heart is highly oedematous. This is the first time that: 1) metabolite ADCs have been measured in isolated heart, and 2) NMR spectroscopy has been used to determine the myocyte diameter. Thus ADC changes may not have potential for detecting ischaemia in the heart, although the measurement of myocyte diameter using taurine ADCs could indicate myocardial oedema.

No description available.

No description available.

published_or_final_version / abstract / Biochemistry / Doctoral / Doctor of Philosophy

An abnormal chronotropic response to exercise is a common finding following surgical repair of tetralogy of Fallot (TOF) which has generally been attributed to a putative sympathetic dysfunction. There exists little information on sympathetic function in patients operated for a congenital heart defect to support such a claim. This study used spectral analysis of heart rate (HRV) and blood pressure (BPV) variability to examine sympathovagal influences on the sinus node in 9 adolescents operated for TOF 13.0 +/- 1.12 years previously and in 8 healthy age and sex-matched control (CTRL) subjects. Continuous ECG and BP recordings were obtained under supine or seated resting positions, with or without controlled respiration at 0.20 Hz (CR); after passive 85° head-up tilt (HUT); during cycling at steady-state heart rates of 100 and 120 bpm (Ex 100, Ex 120), and after 10 and 20 minutes of passive seated recovery. (Abstract shortened by UMI.)

No description available.

Orientador: Célia Regina Nogueira / Banca: Célia Regina Nogueira / Banca: Maeli Dal Pai Silva / Banca: Patrícia Chakur Brum / Resumo: A obesidade é caracterizada pelo acúmulo excessivo de gordura corporal, representando um problema de abrangência mundial que afeta principalmente países industrializados. As comorbidades acarretadas pela obesidade resultam em conseqüências econômicas para a saúde pública e estão associadas com prejuízo da qualidade de vida e aumento da mortalidade. Pesquisas clínicas mostram que o excesso de gordura acarreta diversas anormalidades cardíacas, as quais se relacionam com a duração e intensidade da obesidade. Modelos experimentais, como a obesidade induzida por dieta hipercalórica, têm sido utilizados para o estudo das alterações moleculares, bioquímicas, morfológicas e funcionais acarretadas pelo acúmulo de tecido adiposo. Em razão da carência de estudos relacionando obesidade por dieta hipercalórica e cálcio intracelular miocárdico, o objetivo deste estudo foi analisar a expressão gênica das proteínas do sarcolema, canal L e trocador Na+/Ca2+ (NCX), e do retículo sarcoplasmático, ATPase de cálcio (Serca 2a), receptor rianodina (RyR), fosfolambam (PLB) e calsequestrina (CSQ2), envolvidas na regulação do cálcio intracelular miocárdico de ratos obesos. Ratos Wistar machos, com 30 dias, foram randomizados em dois grupos: controle (C; n=13) e obeso (Ob; n=13). O grupo C recebeu ração Labina (3,3 Kcal/g) e o Ob um ciclo de cinco dietas hipercalóricas ( 4,5 kcal/g) durante 15 semanas. Foram analisados: peso corporal final (PCF), porcentagem de gordura da carcaça (% GC), pressão arterial sistólica final (PA), peso dos ventrículos esquerdo (VE) e direito (VD) e as relações VE/PCF e VD/PCF. O perfil glicêmico foi estimado pelo teste de tolerância à glicose (GTT) e os níveis plasmáticos de insulina e leptina avaliados por ELISA. A expressão gênica das proteínas envolvidas no trânsito de cálcio foi analisada por RT-PCR. Os dados foram expressos... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The obesity is characterized by the extreme accumulation of corporal fat, representing a problem of world-wide embracing that mainly affects industrialized countries. The comorbidities caused by the obesity result in economic consequences for the public health and they are associated with damage of the life quality and increase of mortality. Clinical research shows that the fat excess causes diverse heart abnormalities, which relates with the duration and intensity of the obesity. Experimental models, as the induced obesity by high fat diet, have been used for the study of the molecular, biochemical, morphologic and functional alterations caused by the accumulation of fat tissue. In despite of the lack of studies relating to obesity by high fat diet and myocardium intracellular calcium, the objective of this study was to analyze the expression gene of sarcolemal proteins, L type channel and exchanger Na+/Ca2+ (NCX), and of the sarcoplasmic reticulum, ATPase of calcium (Serca2a), ryanodine receptor (RyR), phospholamban (PLB) and calsequestrin (CSQ2), involved in the regulation of myocardium intracellular calcium of obese rats. Male Wistar rats, with 30 days, were randomly in two groups: control (C; n=13) and obese (Ob; n=13). Group C received a control low-fat diet Labina (3,3 Kcal/g) and the Ob cycles from five high fat diets (4,5 kcal/g) during 15 weeks. Final corporal weight (FBW), percentage of fat of the carcass (%CF), final systolic blood pressure (SBP), weight of the left ventricles (LV) and right (RV) and the ratio LV/FBW and RV/FBW were analyzed. The profile glucose was esteemed by the oral glucose tolerance test (GTT) and the insulin and leptin plasma levels evaluated by ELISA. The expression gene of Ca2+ cycling proteins was analyzed by semi-quantitative RT-PCR. The data were expressed in means l SD... (Complete abstract click electronic access below) / Mestre

No description available.