Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 3 de 3
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Am J Clin Nutr ; 75(2): 228-36, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11815312

RESUMO

BACKGROUND: A high-fat diet has been recommended for correction of biochemical abnormalities and muscle energy state in patients with complex I (NADH dehydrogenase) deficiency (CID). OBJECTIVE: This study evaluated the effects of intravenous infusion of isoenergetic amounts of triacylglycerol or glucose on substrate oxidation, glycolytic carbohydrate metabolism, and energy state in patients with CID. DESIGN: Four CID patients and 15 matched control subjects were infused with triacylglycerol (1.85 mg x kg(-1) x min(-1)) or glucose (5 mg x kg(-1) x min(-1)) while at rest. Respiratory calorimetry was used to evaluate mitochondrial substrate oxidation. Metabolism of glycolytic carbohydrate was determined on the basis of the rates of appearance and concentrations of plasma lactate from dilution of [1-(13)C]lactate measurements. In addition, high-energy phosphate metabolism was measured in forearm muscle by (31)P magnetic resonance spectroscopy. RESULTS: Whole-body oxygen consumption rates were higher in the patients than in the control subjects (P < 0.05). Oxygen consumption and high-energy phosphate metabolism in forearm muscle were not significantly different between the 2 infusion groups. The rates of appearance and concentrations of plasma lactate were higher in each of the 4 patients than in the control subjects (P < 0.05) and were lower during the triacylglycerol infusion than during the glucose infusion (P < 0.05); the differences were comparable in the patients and control subjects. CONCLUSIONS: We conclude that triacylglycerol infusion, relative to glucose infusion, does not improve the oxidation of substrates or the energy state of skeletal muscle and does not lower the rates of appearance and concentrations of plasma lactate to normal values in CID patients at rest.


Assuntos
Lactatos/sangue , Miopatias Mitocondriais/etiologia , NADH NADPH Oxirredutases/deficiência , Triglicerídeos/uso terapêutico , Adolescente , Adulto , Glicemia/efeitos dos fármacos , Calorimetria/métodos , Estudos de Casos e Controles , Complexo I de Transporte de Elétrons , Feminino , Glucose/administração & dosagem , Glucose/uso terapêutico , Humanos , Infusões Intravenosas , Miopatias Mitocondriais/metabolismo , NADH NADPH Oxirredutases/metabolismo , Consumo de Oxigênio , Resultado do Tratamento , Triglicerídeos/administração & dosagem
2.
Am J Clin Nutr ; 75(2): 237-44, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11815313

RESUMO

BACKGROUND: A high-fat diet has been recommended for the treatment of patients with mitochondrial myopathy due to complex I (NADH dehydrogenase) deficiency (CID). OBJECTIVE: This study evaluated the effects of intravenous infusion of isoenergetic amounts of triacylglycerol or glucose on substrate oxidation, glycolytic carbohydrate metabolism, and exercise endurance time and energy state of muscle in CID patients. DESIGN: Four CID patients and 15 control subjects were infused with triacylglycerol (3.7 mg x kg(-1) x min(-1)) or glucose (10 mg x kg(-1) x min(-1)) during low-intensity leg exercise. Respiratory calorimetry was used to evaluate mitochondrial substrate oxidation. The concentration and rate of appearance of plasma lactate (from dilution of [1-(13)C]lactate) were used to evaluate glycolytic carbohydrate metabolism. (31)P magnetic resonance spectroscopy was used to determine ratios of phosphocreatine to inorganic o-phosphate in forearm muscle during exercise. RESULTS: In 3 patients, leg exercise endurance time was better during the triacylglycerol infusion than during the glucose infusion. In all 4 patients, whole-body oxygen consumption rates during exercise were higher during triacylglycerol infusion than during the glucose infusion. In 3 patients, the concentration and rate of appearance of plasma lactate were lower during triacylglycerol infusion than during the glucose infusion. Ratios of phosphocreatine to inorganic o-phosphate during exercise were not significantly different between the 2 infusion studies or between the patients and control subjects. CONCLUSIONS: Triacylglycerol infusion is associated with a greater oxidation of substrates, lower rates of appearance and concentrations of plasma lactate, and greater leg exercise endurance time in myopathic CID patients than is glucose infusion. The energy state of muscle during exercise, however, was not significantly different after infusion of triacylglycerol or glucose.


Assuntos
Glucose/uso terapêutico , Miopatias Mitocondriais/etiologia , NADH NADPH Oxirredutases/deficiência , Resistência Física/efeitos dos fármacos , Triglicerídeos/uso terapêutico , Adolescente , Adulto , Estudos de Casos e Controles , Complexo I de Transporte de Elétrons , Exercício Físico , Feminino , Glucose/administração & dosagem , Humanos , Infusões Intravenosas , Lactatos/sangue , Espectroscopia de Ressonância Magnética , Miopatias Mitocondriais/metabolismo , NADH NADPH Oxirredutases/metabolismo , Consumo de Oxigênio , Triglicerídeos/administração & dosagem
3.
J Am Soc Nephrol ; 12(5): 1017-1025, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11316861

RESUMO

The urinary loss of transferrin is sufficient to reduce plasma transferrin concentrations in the nephrotic syndrome. Hypotransferrinemia may lead to iron loss and microcytic anemia. The mechanism responsible for the hypotransferrinemia in the nephrotic syndrome is, however, unknown. In the present study, synthesis rate of transferrin was measured in vivo in nephrotic patients (n = 7) compared with control subjects (n = 6) using L-[1-(13)C]-valine. Plasma transferrin and iron concentration in the patients were significantly lower than in control subjects (transferrin, 1.39 +/- 0.08 versus 2.57 +/- 0.11 g/L, P < 0.0001; iron, 10.2 +/- 0.8 versus 21.1 +/- 4.5 micromol/L, P = 0.02). Furthermore, albuminuria correlated with transferrinuria (r(2) = 0.901, P = 0.001). The absolute synthesis rate of transferrin was increased in the patients (10.0 +/- 1.1 versus 7.4 +/- 0.7 mg/kg per d, P = 0.07), although this value failed to achieve significance. C-reactive protein, plasma iron, and proteinuria did not correlate with transferrin synthesis. In contrast, transferrin synthesis correlated with albumin synthesis (r(2) = 0.648, P = 0.03; n = 7). The present study indicates that increased transferrin synthesis occurs in nephrotic patients but is insufficient to compensate for urinary losses. Because, overall, no significant relationship was found between transferrin synthesis and either C-reactive protein or iron, it is unlikely that inflammation suppresses or that iron deficiency stimulates increased transferrin synthesis in these patients. The correlation between transferrin synthesis and albumin synthesis suggests that transferrin synthesis is a component of a general response in hepatic protein synthesis in the nephrotic syndrome. This suggests that a therapeutic approach to maximize plasma transferrin concentrations in nephrotic patients should be aimed primarily at reducing urinary protein excretion.


Assuntos
Síndrome Nefrótica/metabolismo , Transferrina/biossíntese , Adulto , Albuminas/biossíntese , Estudos de Casos e Controles , Feminino , Humanos , Ferro/sangue , Cinética , Masculino , Pessoa de Meia-Idade , Síndrome Nefrótica/complicações , Síndrome Nefrótica/urina , Proteinúria/etiologia , Proteinúria/metabolismo , Transferrina/urina
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...