Biomedical subjects
Publications and source records attributed to L Borghi.
A method is described for the determination of oxalate in urine using flow injection analysis and fluorimetry. Oxalate is precipitated with calcium chloride at pH 4.5, redissolved in H2SO4 and measured by flow injection analysis. The minimum detection limit is 6 mumol/l. The coefficient of variation is 7%. Results are in good accordance with normal values found with traditional oxalate analysis.
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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.
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.
The effects of a moderate surgical trauma on body composition, in conditions comparable to fasting were assessed in a balance study. Two groups of patients under normal nutritional conditions were compared after cholecystectomy. The patients underwent for three days the following schedules of parenteral therapy: incomplete nutrition with balanced intake of water, sodium and potassium but carbohydrate deficient and lacking in amino acids (group 1, 10 cases); or complete nutrition with respect to calories, amino acids and other electrolytes (group 2, 9 cases). An evident loss in body weight was observed in patients undergoing incomplete nutrition, not justified by a moderately negative water balance. Statistical comparison of the two groups showed equal or positive balances for group 1 while group 2 gave negative results for all the parameters, particularly for nitrogen and potassium, suggestive of a loss in lean body mass greater than that usually occurring after simple fasting. Results confirmed the poor significance of serum values in expressing even significant degrees of electrolyte depletion. Substantial modifications in body composition may appear as clinical manifestations in cases with pre-existing malnutrition or when drugs that affect or are affected by the water and electrolyte balance are administered.
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.
An original method for measuring the effects of furosemide on sodium efflux from human lymphocytes into an Na-free medium is proposed. The comparison between normotensive and hypertensive subjects shows reduced furosemide-sensitive fluxes in some hypertensives.
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.
In 21 patients with acute hypophosphatemia (AHPP), we measured red cell intracellular Na concentration (Nai) and either total (T), ouabain-sensitive (OS) or ouabain-resistant (OR) efflux rate constant of Na (0K Na) in a 'physiological' Na medium. High Nai, normal 0K Na T, reduced 0K Na OS and normal 0K Na OR were found. Total OS and OR unidirectional Na effluxes were increased, normal and increased, respectively. The findings suggest that high Nai in AHPP is due to an impairment of active (OS) red cell Na transport; the increase of total Na efflux is only supported by the OR Na efflux, which, under physiological conditions, is mediated mostly by the 1 Na:1 Na exchange diffusion.
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.
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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.
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.
An in vitro study of the nuclear magnetic resonance (NMR) response of protons in normal and pathological human skeletal muscle is presented. Muscle biopsies from 34 patients with various neuromuscular diseases and five normal subjects were studied by proton NMR techniques and the results were compared with those of light and electron microscopy. Proton spin-lattice relaxation time (T1) and recovery law for the nuclear magnetization have been determined at 37 degrees C and 43.5 MHz. The T1S for normal tissues were in the 650 to 800 ms range and the recovery process was nearly exponential. Muscles with well defined neuromuscular diseases were associated with highly nonexponential relaxation processes. The relationship between morphological alterations of the muscle tissues and the proton NMR response may become the basis of a fast and simple method for the diagnosis of neuromuscular diseases.
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.
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1. Erythrocyte lithium--sodium countertransport was measured in 46 normotensive healthy controls without family history of hypertension, 15 subjects with essential hypertension, but without evidence of family history of high blood pressure, and 43 subjects with essential hypertension and at least one hypertensive first-degree relative. 2. Mean values (mmol h-1 l-1 of erythrocytes) were 0.248 +/- 0.092 in controls, 0.258 +/- 0.087 in hypertensive subjects without family history (not significant vs controls), 0.360 +/- 0.115 in hypertensive subjects with family history of hypertension (P less than 0.001 vs controls), 0.334 +/- 0.117 in all hypertensive subjects, both with and without family history (P less than 0.001 vs controls). 3. Our data confirm the finding of an increased erythrocyte lithium--sodium countertransport, but with a significant overlap between essential hypertension and control values. Lithium--sodium countertransport is higher only in hypertensive subjects with at least one hypertensive first-degree relative. 4. We suggest that the increase of lithium--sodium countertransport in erythrocytes is not a consistent marker of essential hypertension. It seems to be associated with the family prevalence and/or the hereditability of hypertension, rather than with high blood pressure per se.