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Brief periods of fasting or moderate trauma were previously shown to give rise to malnutrition characterized by negative nitrogen balance, reduction of lean body mass and relative increase of body water. The present study aimed to assess the possibility that brief low-calorie, low-protein parenteral fluid regimen after relatively moderate surgical trauma can modify the muscle metabolism and alter the water, electrolyte and protein composition. Well-nourished patients undergoing elective cholecystectomy were studied. During the first four postoperative days, seven patients (group I) received parenteral nutrition adequate as regards water, sodium and potassium but deficient in carbohydrates and without amino acids, while six patients (group II) had adequate parenteral supply of calories and nitrogen. The extracellular balance in regard to water, sodium, potassium, calcium, phosphorus, magnesium and urea was assessed in all 13 patients. Needle biopsy of muscle was performed during surgery and at the end of the observation period in six patients from group I and five from group II, in order to assess the total and the intracellular and extracellular water content and also sodium, chloride, potassium, magnesium, phosphorus and alkali-soluble protein nitrogen. In group I, but not in group II, there was weight loss and negative extracellular balance of all parameters, in particular potassium and nitrogen, and reduction of muscle potassium. The analyses of balance and of muscle cell composition showed considerable loss of lean body mass and indicated 'true' electrolyte disturbance, although clinical symptoms were absent and serum parameters remained normal.

Plasma and skeletal muscle free amino acids were measured in patients submitted to Hemodialysis (HD) or Continuous Ambulatory Peritoneal Dialysis (CAPD) in order to evaluate the effects of these different dialysis modalities on amino acid pools; the data were compared with those obtained in control subjects and in patients with advanced Chronic Renal Failure (CRF) not submitted to Regular Dialysis Treatment (RDT). Our findings show low intracellular concentrations of VAL, total Branched Chain Amino Acid (BCAA) and TYR in uremic patients treated with CAPD but not in those undergoing HD. The observed differences in muscle amino acid pattern could be well explained by a changed amino acid metabolism regulation in CAPD, possibly related to the sustained hyperinsulinism and to an increased rate of hepatic protein synthesis.

Skeletal muscle water, Cl, Na and K were studied in 24 patients with predialysis chronic renal failure (CRF) and in 16 patients under regular dialysis treatment (RDT) for 8-16 years; 35 healthy controls were also examined. Total Cl, Na and water (Clm, Nam, TW) were high in both CRF and RDT groups (p less than 0.001); high TW in CRF was due to both extra (ECW) and intracellular (ICW) fractions, which were calculated from Cl space; in RDT only ECW was increased and ICW was normal. Muscle K was diminished in CRF, in reference to both muscle fat free dry solids and ICW, and it was slightly but significantly higher than normal in RDT. The findings demonstrate that high cell volume and low intracellular K observed in CRF are fully corrected by long-term hemodialysis, probably because these abnormalities are mainly related to cell function disturbances due to uremic state. On the contrary, the persistence of high total Cl, Na and muscle ECW seems to be an expression of expanded extracellular fluid volume.

Muscle tissue H2O, Na, K, Mg, Cl and total P were studied in 23 patients with acute hypophosphatemia during P-deficient total parenteral nutrition. Increased muscle extracellular water and low intracellular K and Mg with high intracellular Na were found. These abnormalities were detected either in previously underfed patients with low muscle P or in well-nourished, acutely ill subjects with muscle P near to normal. These findings show that acute depletion of extracellular inorganic P is associated with changes of muscle cell composition independently of muscle cell P content.

Insulin-dependent diabetes mellitus (IDDM) induces plasma amino acid (AA) abnormalities, including low alanine and high branched-chain (BCAA). While insulin treatment restores plasma AA pattern, proline, methionine, valine, isoleucine, and total BCAA remain elevated in skeletal muscle intracellular water. This suggests that the restoration of plasma AA concentrations is not a satisfactory index of recovered AA metabolism in IDDM.

Free amino acids were measured under postabsorptive conditions in plasma and intracellular water of skeletal muscle obtained by needle biopsy in nine healthy controls and 14 subjects suffering from clinically stable liver cirrhosis. The aromatic amino acids phenylalanine and tyrosine in cirrhotics were elevated to the same extent in plasma and in muscle water. Branched-chain amino acids were uniformly reduced in plasma, but in muscle water only valine was significantly lower (222 +/- 92 mumoles per kg intracellular water vs. 368 +/- 82, p less than 0.001), while isoleucine (142 +/- 63 vs. 103 +/- 30), leucine (223 +/- 88 vs. 226 +/- 36) and branched-chain amino acids as a whole (589 +/- 186 vs. 681 +/- 88) were normal or elevated with an increased muscle:plasma ratio (3.12 +/- 2.03 vs. 1.41 +/- 0.37, p less than 0.05 for isoleucine; 3.00 +/- 1.28 vs. 1.85 +/- 0.27, p less than 0.025 for leucine; 2.24 +/- 0.64 vs. 1.69 +/- 0.13, p less than 0.05 for total branched-chain amino acids. Our data show that, in cirrhosis, plasma concentrations of branched-chain amino acids do not reflect their levels in muscle cellular water; only the intracellular pool of valine is severely depleted. This suggests that higher amounts of valine supplementation may be useful in nutritional treatment of liver cirrhosis. The elevated muscle:plasma gradients for branched-chain amino acids may result from abnormalities in their transport through muscle-plasma membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

This paper deals with the possibility of using proton (1H) NMR as a diagnostic tool for discriminating between normal and diseased tissues. As an example, we analyze in vitro the 1H NMR response of muscle from patients with neurogenic muscle diseases. It is suggested that there is correlation between the tissue morphology and some details of the proton relaxation processes. Our findings can be of relevance to a clinical application of NMR tomography.

The question whether body electrolyte composition in patients with primary hypertension differs from that of normotensive subjects is still controversial. The aim of the present work was to investigate on water, electrolyte, and nitrogen muscle cell composition in essential human hypertension. Also the effects of antihypertensive drugs on muscle electrolyte contents were analyzed. The results indicate that muscle Na was higher and muscle K was lower in essential hypertensives in comparison with controls. Muscle water, Mg, and nitrogen were not different in treated patients (with or without diuretics) in comparison with untreated hypertensive patients. But in hypertensive patients treated with diuretics, Nam was higher and Km was lower than in untreated patients. Several mechanisms may explain the changes on muscle electrolyte composition in primary hypertension, but the cellular mechanism involving abnormalities in ion pump and electrolyte transmembrane fluxes are the most probable. The therapy with antihypertensive drugs especially diuretics, seems to enhance different muscle electrolyte patterns in essential hypertension.

Report of a study of primary myopathies in children conducted within the framework of our program to evaluate the diagnostic potential of 1H NMR in muscular diseases. There are substantial differences in the in vitro 1H NMR response of skeletal muscles between normal children and children with congenital non progressive myopathies and Duchenne muscular dystrophy.