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Biomedical subjects

A Novarini

Publications and source records attributed to A Novarini.

At least 73 records · Page 4Linked to original sources
PubMed1985

Skeletal muscle water and electrolytes in chronic renal failure. Effects of long-term regular dialysis treatment.

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.

Adult↗
PubMed1985

Low-pressure receptor activity and exaggerated natriuresis in essential hypertension.

Urinary sodium excretion, central hemodynamics, and mean arterial pressure (MAP) were studied in 7 normal subjects and 19 hypertensive patients during both central hypervolemia by water immersion to the neck (NI) and extracellular volume expansion by i.v. saline infusion. During 2-hour NI, 12 out of the 19 hypertensives exhibited a significant fall in MAP (p less than 0.001). Exaggerated natriuresis did not occur in these patients (ns). In the remaining 7 hypertensive patients in whom, during NI, MAP was unchanged, exaggerated natriuresis was found (p less than 0.001). During saline infusion, MAP was either unchanged or increased and exaggerated natriuresis was found in all hypertensive patients (p less than 0.001) previously submitted to NI. Our findings suggest that a high MAP is a major determinant of exaggerated natriuresis in arterial hypertension.

Adolescent↗
PubMed1985

Plasma and skeletal muscle free amino acids in type I, insulin-treated diabetic subjects.

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.

Adult↗
PubMed1985

Metabolic, water and electrolyte changes after moderate surgical trauma. Observations after different schedules of parenteral nutrition.

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.

Adult↗
PubMed1985

Skeletal muscle water and electrolytes in treated and untreated essential hypertension.

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.

Adult↗
PubMed1984

Ouabain-resistant, frusemide-sensitive sodium efflux in human lymphocytes: a comparison of normotensive and hypertensive subjects.

Peripheral blood lymphocytes were isolated at room temperature in a low sodium medium in 17 normotensive control subjects (NC) and 13 patients with essential hypertension (EHP). Lymphocyte sodium content was not significantly different between NC and EHP (3.1 +/- 0.5, n = 11, and 3.6 +/- 0.5, n = 10, respectively; means +/- SEM). The effect of frusemide on the ouabain-resistant rate constant of sodium efflux (KNao) from these lymphocytes into a sodium-free medium was measured. The frusemide-sensitive efflux rate constant was 75 +/- mus (n = 17) in controls and significantly lower in EHP (32 +/- 7 mus, n = 13, P less than 0.001). In human lymphocytes there is a ouabain-resistant, frusemide-sensitive fraction of sodium efflux into a sodium-free medium; this fraction may be reasonably attributed to a sodium-potassium cotransport system. This sodium transport pathway seems to be reduced in lymphocytes from EHP.

Adult↗
PubMed1984

Effects of 'central hypervolemia' by Water immersion on renin-aldosterone system and ACTH-cortisol axis in hemodialyzed patients.

Water immersion up to the neck (WI) results in a central hypervolemia; the increased atrial pressure, evoked by this maneuver, stimulates low pressure receptors (LPR) which exert tonic inhibition on sympathetic activity and suppresses both the renin (PRA)-aldosterone (PA) system and the ACTH-cortisol axis in normal man. In hemodialyzed patients (HP), in whom autonomic neuropathy has been frequently found, PRA and ACTH were not suppressed during WI while plasma cortisol and PA were reduced. Other modulators, like dopamine, are supposed to be involved in regulating cortisol and PA levels in HP.

Adrenocorticotropic Hormone↗
PubMed1984

Erythrocyte sodium transport in acute hypophosphatemia in man.

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.

Acute Disease↗
PubMed1984

Skeletal muscle cell abnormalities in acute hypophosphatemia during total parenteral nutrition.

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.

Acute Disease↗
PubMed1983

Extracellular water, electrolyte and nitrogen balance after postoperative parenteral nutrition and intracellular involvement in muscle.

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.

Adult↗
PubMed1982

Muscle tissue electrolytes in burned subjects.

In a group of patients with burns covering at least 20 per cent of their body surface area (BSA), extracellular electrolytes and acid-base status and intracellular electrolytes and nitrogen (muscle needle biopsy) were measured both in the early phase (12-24 hours) and 7-14 days after burn injury. In the acute burn phase, extracellular electrolyte and acid-base disturbances are uncommon, while intracellular data shows increase of muscle sodium, decrease of muscle potassium and magnesium and normal muscle cell nitrogen. In the later burn phase, despite an adequate fluid, electrolyte and protein-calorie supply, the changes of electrolytes appear to be uncorrected; no decrease of muscle cell nitrogen is found. Our data could suggest that defects of the sodium-potassium pump in the cell membrane, which are thought to be the cause phase of burns, do not ameliorate with adequate fluid and protein-calorie intake; however, a persistent muscle potassium depletion is also consistent with a reduction of cell "capacity' for potassium, possibly due to muscle protein catabolism, although muscle cell protein values do not show a significant reduction.

Acid-Base Equilibrium↗
PubMed1982

[Effects of passive semiorthostatic cardiopulmonary hematic centralization (by immersion in water) on hydrosaline elimination and on the renin-angiotensin-aldosterone system in essential hypertension].

In 25 patients with essential hypertension and 9 control subjects we have studied the effects of central hypervolemia during water immersion on both renin-angiotensin-aldosterone system and renal function (diuresis volume and urine excretion of Na, k and osmoles). Reduction of blood pressure, plasma renin activity and aldosterone was found to be similar in both groups; renal excretion of water, Na, K and osmoles was significantly higher in the hypertensive group compared to the controls. These urinary features may be related to a reduced proximal tubular reabsorption by cardiorenal reflex due to cardiopulmonary volume receptors stimulation without any change of GFR measured as the creatinine clearance. The urinary pattern, observed during water immersion in hypertensive group without any change of plasma sodium, osmolality or protein concentration, was comparable to "exaggerated natriuresis"; this may suggest that also "exaggerated natriuresis" is due either to renal vasodilatation or to renal tubular sympathetic activity reduction secondary to a cardiorenal reflex by cardiopulmonary volume expansion.

Adolescent↗