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Biomedical subjects

G Marra

Publications and source records attributed to G Marra.

At least 91 records · Page 5Linked to original sources
PubMed1992

Serum levels of soluble interleukin-2 receptor (sIL-2R) in B-chronic lymphocytic leukemia.

By using an enzyme-linked immunosorbent assay, the levels of the soluble form of the interleukin-2 receptor (sIL-2R) were evaluated in the peripheral blood of 20 patients with cell chronic lymphocytic leukemia in different stages of disease and in supernatants obtained from enriched B cell suspensions. In either all serum samples or in one out of three supernatants, elevated levels of sIL-2R were found. This could indicate that the B leukemic cells release sIL-2R which in turn, for its potential capacity of binding circulating IL-2, could contribute to the abnormal immunoregulation which characterizes B-CLL. This finding, which needs further investigation, could have prognostic significance.

Aged↗
PubMed1991

The learning and fatigue effect in automated perimetry.

A visual field test was performed on 100 volunteers to study learning or fatigue effects during one session. The test was carried out with the help of the Octopus program J1, which measures the threshold 12 times at 3 test locations. In the majority of cases the sensitivity was quite stable during the session. We noted no difference between trained and untrained subjects or between normal and pathological eyes. However, patients with refractive errors, especially myopes, revealed a larger learning effect than did emmetropes.

Adolescent↗
PubMed1990

Increased sodium requirement following early postnatal surgical correction of congenital uropathies in infants.

Serum electrolyte equilibrium and plasma aldosterone concentrations were monitored in 19 infants who had severe obstructive uropathy or grade 5 vesico-ureteral reflux and were undergoing surgical correction in the first 2 months of life. Before surgery high plasma aldosterone levels were observed in 8 patients, but serum sodium and potassium concentrations were normal. Plasma concentrations of aldosterone were elevated in all patients during the week following surgery and 7 patients developed severe hyponatraemia, hyperkalaemia and weight loss despite very high plasma aldosterone concentrations. As a consequence 5 infants were infused with sodium chloride (4 mEq/kg per day) before and for 36 h after surgery; this prevented metabolic imbalance. We conclude that infants undergoing surgical correction of uropathies may require a high sodium intake to maintain electrolyte balance and adequate growth.

Aldosterone↗
PubMed1990

Sodium excretion and hyperfiltration during glucose infusion in man.

The relations between renal hemodynamics (Inutest, CPAH) and sodium excretion were studied in 7 nondiabetics in whom a similar expansion was induced (1) with a 3-hour 5% glucose infusion and (2) with a 0.9% saline load. With both infusions the body weight increased, hematocrit fell, and the plasma renin activity was suppressed. During glucose infusion, blood glucose rose from 3.9 mmol/l to a plateau of around 13 mmol/l; glycosuria was absent during the 1st h, then appeared and stabilized during the following 2h. Glucose infusion caused a progressive increase in glomerular filtration rate and in renal blood flow in both absence and presence of glycosuria, without significant changes in sodium excretion despite volume expansion and increase of filtered sodium load. When saline was infused, there was a sustained increase of fractional sodium excretion, and no hemodynamic modifications were observed. We suggest that a primary glucose-induced metabolic stimulation of sodium reabsorption may play a role in the genesis of glucose-induced hyperfiltration.

Adolescent↗
PubMed1988

Lack of glomerular hemodynamic stimulation after infusion of branched-chain amino acids.

Renal hemodynamics (Inutest. CPAH) were studied in five adult volunteers infused on separate occasions with branched-chain amino acids (BCAA), a mixture of nonessential and essential amino acids of the same volume, osmolality and nitrogen content, and 0.9% saline solution. BCAA infusion caused moderate renal vasoconstriction, a slight increase of GFR and a progressive rise of the filtration fraction (FF), whereas the amino acids mixture induced a significantly higher increase of GFR and a state of renal vasodilatation without altering the FF. The volume expansion with 0.9% saline did not cause any notable hemodynamic modification except for reduced FF. This study demonstrates that whereas a state of hyperfiltration and hyperemia is specifically induced by an amino acid mixture independently of volume expansion and osmolar load, the administration of BCAA provides nitrogen without renal hemodynamic stimulation.

Adult↗
PubMed1988

Proximal tubular function and hyperfiltration during amino acid infusion in man.

The relations between renal hemodynamics (Inutest, CPAH) and sodium segmental handling (sodium distal delivery, distal reabsorption, and fractional excretion) were studied in 9 healthy adults infused with an isotonic amino acid solution and in 6 subjects infused with 0.9% saline for 3 h at 0.2 ml/min/kg. During all tests maximal water diuresis was induced and maintained to effect analysis of sodium segmental transport. Both types of infusion produced a similar expansion of extracellular volume (weight increase, hematocrit fall, suppressed plasma renin activity and plasma aldosterone). The amino acid infusion increased the glomerular filtration rate (GFR) and renal blood flow without modifying the filtration fraction. With saline no hemodynamic modifications were observed. The expansion with saline depressed proximal and distal sodium reabsorption whereas during amino acid infusion sodium distal delivery was unaltered and the significantly increased sodium fractional excretion was sustained only by depressed distal reabsorption. Therefore, in parallel with the GFR increase, closely dependent on renal vasodilatation, the well-known stimulation of sodium cotransport by amino acids is able to antagonize the effects of expansion on the proximal sodium reabsorption. An explanation of glomerular hyperfiltration based on a primary metabolic stimulation of the proximal tubular function is suggested.

Adult↗
PubMed1987

Persistent tubular resistance to aldosterone in infants with congenital hydronephrosis corrected neonatally.

Renal function of 18 infants who had undergone surgery in the neonatal period because of severe congenital hydronephrosis was followed up for 5 to 36 months (mean +/- SD 21 +/- 10 months). In all cases the diagnosis was made prenatally by sonography and confirmed at birth by intravenous urography. Creatinine clearance developed normally in all the children. Eight had a reduction in maximal urinary concentrating ability after intranasal DDAVP; this defect was transient and resolved after 4 to 5 months in all but one child, in whom it persisted. However, other tubular abnormalities were present. Throughout the observation period, patient serum potassium concentrations were significantly higher than normal, paralleled by a significant increase in plasma aldosterone concentration but with normal excretion fraction of sodium and potassium. There were no disturbances of acid-base balance. These findings may be accounted for by a persistent partial reduced sensitivity of the distal tubule to the action of aldosterone despite normal renal function. This alteration is usually mild, but may constitute a persistent metabolic risk despite successful surgical intervention.

Aldosterone↗
PubMed1986

Esophageal involvement in Behçet's syndrome.

Two patients with Behçet's syndrome had severe esophageal involvement. Both presented the complete clinical pattern (oral, genital, and eye lesions) of Behçet's syndrome. In both, esophageal lesions were associated with other gastrointestinal manifestations, in the first a transient episode of ulcerative ileitis, and in the second patient colitis. In both, the differential diagnosis with inflammatory bowel disease was very difficult. Histology of esophageal lesions was nonspecific; no vasculitis was found. Both patients improved on steroid therapy. Esophageal lesions also improved endoscopically and histologically with steroid therapy. When there is obvious gastrointestinal involvement in Behçet's syndrome, the differential diagnosis from inflammatory bowel disease is very difficult.

Behcet Syndrome↗
PubMed1986

Renal tubular acidosis in a case of Shwachman's syndrome.

We describe metabolic acidosis in a 15-month-old girl with clinical features of Shwachman's syndrome. Renal function tests indicated that the patient had type 1 renal tubular acidosis. Based on our findings and other reports of renal tubular dysfunction in patients with Shwachman's syndrome, we conclude that it is important to look for a possible renal tubular defect in this syndrome.

Acidosis, Renal Tubular↗
PubMed1986

Early childhood hyperkalemia: variety of pseudohypoaldosteronism.

Fractional excretion of electrolytes, renal acidification capacity and the renin-aldosterone system have been studied in 5 non-azotemic children, 19-25 months old, with mineralocorticoid resistant hyperkalemia, discovered in the first month of life. Although fractional potassium excretion was similar in patients and in a group of control healthy children (13.8 +/- 5.2% vs. 8.7 +/- 6.4%) it was inappropriately low in the patients for their higher potassium concentration. Fractional sodium excretion was significantly increased in the patients (1.6 +/- 0.3% vs. 0.67 +/- 0.4, p less than 0.02). Normal net acid and ammonium excretion and intact ability to lower urinary pH during acid loading were observed in all patients. Mean values for plasma aldosterone (37.0 +/- 9.1 vs. 13.9 +/- 11.2 ng/dl), plasma renin activity (12.5 +/- 3.9 vs. 8 +/- 2.8 ng/ml/h) and plasma aldosterone/plasma potassium ratio (7.11 +/- 1.5 vs. 3.08 +/- 1.7) were higher in the patients than in the control subjects (all p less than 0.001). These data support the hypothesis that a partial lack of response of the renal tubule to endogenous mineralocorticoids was present in the patients. This type of pseudohypoaldosteronism is less severe than that described for the classic form and for early childhood renal acidosis.

Aldosterone↗
PubMed1986

Progression of mineral metabolism derangements in childhood chronic renal failure.

2 groups of children affected by different degrees of chronic renal failure (group 1, 55-36 ml/min/1.73 m2; group 2, 35-20 ml/min/1.73 m2 of creatinine clearance) due to tubulo-interstitial disease were studied for one year. The spontaneous evolution of altered mineral metabolism at different levels of glomerular filtration rate (GFR) was aimed at. Parathyroid hormone, vitamin D metabolites and bone mineral content were evaluated. At the end of the year, only a decrease of plasma levels of 1,25(OH)2D in group 1 and a worsening of all mineral metabolism parameters in group 2 were found. The results are consistent with the hypothesis that mineral metabolism derangements progress rapidly after a certain 'threshold' of endocrinologically active renal mass is reached. The falling of plasma 1,25(OH)2D levels below a still undetermined critical value might be assumed as an index of this threshold.

Adolescent↗
PubMed1986

Prediction of the progression of renal failure in adult and in pediatric patients with malignant focal glomerulosclerosis.

A retrospective analysis of the progression of renal failure was performed in 6 children and 5 adults with idiopathic nephrotic syndrome unresponsive to steroids and immunosuppressants and with histological findings of focal glomerulosclerosis. We analyzed the linear regression of Ccr and of their logarithmic transformation vs time (months) starting from the time when the first abnormal value was observed (t = 0). The regression analysis was performed at three different times, when Ccr was: 30-20, 20-25 and 10-15 ml/min/1.73 sqm. Extrapolation of each of these lines on the x axis predicted when renal function would be zero. The difference in months, between the predicted and actual time of starting dialysis was prediction error. "r" values were always elevated and statistically significant for both linear and logarithmic regression; there was a large intersubject variability in the rate of loss of renal function but the mean prediction error at various levels of Ccr was within limits clinically acceptable. Moreover its magnitude did not significantly decrease by prolonging the time of observation. This indicates that in this disease the decay of Ccr enters a track which proceeds linearly or logarithmically after the onset of renal failure and no major deviation from the predicted line is to be expected. The good predictability in our study may be attributed to the fact that our patients were homogeneous for a number of factors which may be relevant to progression of the disease. It confirms the view supported by Gretz et al. [1983] that there is a need for stratification of patients in large cohort studies on the predictability of loss of renal function.

Adolescent↗