[Diagnostic strategy for mitochondrial diseases]. / Estrategia diagnóstica de las enfermedades mitocondriales.

OBJECTIVE: The variability of both phenotypic and genotypic expression in mitochondrial diseases makes clinical diagnosis difficult, which is essential to establish therapy, aid in genetic counselling or for performing prenatal diagnosis. We have therefore proposed a strategy to help determine correct diagnosis of these alterations, in an attempt to rationalize the number of tests and, whenever possible, avoid tissue biopsy and minimize the size of the biopsy when indicated. DEVELOPMENT: Based on mitochondrial metabolism and molecular bases, as well as their alterations, a preliminary metabolic examination is carried out including at least one study of cytoplasmatic (lactate/pyruvate) and mitochondrial oxide reduction (hydroxibutirate/acetoacetate) in basal conditions or, if required, following glucose overload or an effort test. Metabolic study, in addition to clinical exploration, are the screening tests used to determine the need for tissue biopsy in which biochemical (pyruvate dehydrogenase, free and total carnitine, beta oxidation enzymes and respiratory chain complexes), genetic (mitochondrial DNA or nuclear alterations) and histologic tests are carried out to confirm diagnosis. CONCLUSIONS: a) Metabolic exploration may discard mitochondrial disease and many cases, avoid the use of an invasive procedure such as tissue biopsy. b) Biochemical study of tissue biopsy is the only useful key in the confirming of the diagnosis when no mitochondrial and/or nuclear DNA are observed.

[Anthropometric changes and nitrogen balance in patients with morbid obesity treated with very low calorie diet]. / Modificaciones antropométricas y balance de nitrógeno en pacientes con obesidad mórbida tratados con dieta muy baja en calorías.

BACKGROUND: Morbid obesity is associated with increased morbidity and mortality. In these patients, weight reduction reduces associated morbidity and increases life expectancy. The aim of the present study was to evaluate the anthropometric changes in a group of patients treated with a very low caloric diet and to assess nitrogen balance and clinical and biological tolerance. METHODS: Overall 65 patients were prospectively evaluated (12 males and 53 females with a mean age of 45 +/- 7 years. Mean initial weight was 110 +/- 21 kg, with a Quetelet index of 43 +/- 7 kg/m2. They were treated as inpatients during 42 days exclusively with a very low caloric diet. They also followed a physical exercise program during one hour daily. RESULTS: The weight reduction was 15 +/- 4 kg (p less than 0.0001) with a reduction in fat mass of 9 +/- 2 kg (p less than 0.0001) and a reduction in fat-free mass of 6 +/- 3 kg (p less than 0.0001). The Quetelet index was reduced in 5 +/- 1 points (p less than 0.0001). There was also a reduction in the muscle adipose index from 1 +/- 0.2 to 0.7 +/- 0.2. The nitrogen balance remained negative throughout the 42 study days, although with a clear trend towards equilibrium. There were significant reductions in blood glucose, proteinemia, total cholesterol and subfractions. Triglycerides did not show significant changes. Clinical tolerance was excellent in all cases except 4 who withdraw from treatment because of nausea and vomiting. CONCLUSIONS: In this study, very low caloric diet achieved satisfactory weight reduction, basically at the expense of adipose tissue, reflected in a reduction of the muscle adipose index. Nitrogen balance remained negative throughout the treatment but with a trend towards normalization. Tolerance was excellent in 61 of the 65 cases (94%).