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Biomedical subjects

A Fabris

Publications and source records attributed to A Fabris.

At least 55 records · Page 3Linked to original sources
PubMed1985

Renal acidification defects in patients with recurrent calcium nephrolithiasis.

The frequency of renal tubular acidosis was evaluated in 28 adult patients with recurrent calcium nephrolithiasis (19 with 'renal' hypercalciuria, 9 with normocalciuria and no metabolic abnormality) and no evidence of obstruction or infection of the urinary tract. Eight patients with hypercalciuria (42%) had a defective renal reabsorption of bicarbonate, based on a fractional excretion of bicarbonate higher than 7% and a TmHCO3/GFR lower than 2.2 mEq/dl; 2 of them had an associated distal defect of acidification, as judged by a U-B pCO2 lower than 18 mm Hg in maximally alkaline urine. One patient with hypercalciuria had distal tubular acidosis, based on a urine pH higher than 5.3 during acidosis. Only 1 patient with normocalciuria had associated proximal and distal acidification defects. The remaining 8 patients displayed a normal renal acidifying capacity. The bicarbonate wastage was independent of serum PTH levels, vitamin D status and hypercalciuria and was associated with a defective tubular reabsorption of phosphate, increased random urinary pH and more active nephrolithiasis, with a prevalence of mixed calcium oxalate and phosphate stones. Our study shows a high incidence of defective tubular reabsorption of bicarbonate in patients with calcium nephrolithiasis and 'renal' hypercalciuria and suggests that the proximal acidification defect plays a pathogenetic role in promoting calcium nephrolithiasis.

Acidosis, Renal Tubular↗
PubMed1984

Bone histology and calcium metabolism in patients with nephrotic syndrome and normal or reduced renal function.

Bone histology and its relationship with calcium metabolism was evaluated in adult patients with nephrotic syndrome: 29 had normal renal function (GFR 103 +/- 4 ml/min/1.73 m2) (group 1) and 20 had renal insufficiency (GFR 31 +/- 4 ml/min/1.73 m2) (group 2). In group 1, serum PTH, 1.25-HCC and 24.25-HCC levels were normal, while 25-HCC values were reduced. Bone histology was normal in 76% of the patients, while 17% had isolated osteomalacia and 7% an associated bone resorption. Group 2 showed a higher incidence of bone resorption when compared with a matched group of patients with renal failure and no proteinuria (40% vs. 13%) and a comparable frequency of isolated mineralization defect (25% vs. 34%). PTH levels were definitely increased and serum total calcium and all the vitamin D metabolites were reduced. A significant correlation between the apparent duration of the disease and the severity of osteodystrophy was found only in group 2. In conclusion, no constant derangement of calcium metabolism and bone histology is evident in patients with nephrotic syndrome and normal renal function, while patients with persistent proteinuria are at high risk of osteodystrophy even in the early phases of renal failure.

Adolescent↗
PubMed1984

The role of neurotransmitters in the genesis of uremic encephalopathy.

To classify the influence of neurotransmitters in the genesis of uremic encephalopathy we studied cerebrospinal fluid (CSF) and plasma (P) amino acid (AA) concentration, in patients undergoing various dialytic treatments (hemodialysis = HD, intermittent and continuous peritoneal dialysis = IPD and CAPD). HD causes a significant decrease in CSF/P ratios of branched chain AA (BCAA) and a significant increase in CSF Glycine/Valine ratio, suggesting an augmented brain uptake of Glycine at detriment of Valine. In IPD the general trend of Aromatic AA/BCAA ratio suggests a preferential transport of Aromatic AA through the blood brain barrier. The differences between IPD and HD are confirmed by data concerning metabolites of Serotonin and Dopamine: CSF concentrations of 5- Hydroxyindoleacetic acid and Homovanillic acid are low in HD but high in IPD. So, a reduced (in HD) and an increased (in IPD) activity of monoamine systems could be at the basis of some neurological disturbances appearing in uremia.

Adolescent↗
PubMed1984

Effects of timolol on blood pressure, systemic hemodynamics, plasma renin activity, and glomerular filtration rate in patients with essential hypertension.

Timolol, a non-cardioselective beta-blocking agent, was administered orally after 2 weeks of placebo to 14 patients with essential hypertension for 8 weeks following 1-4 weeks of dose-ranging period. Patients were first hospitalized and submitted to a diagnostic workup. They were placed on a diet containing 100 mEq of Na+ and 65 mEq of K+; this regimen was also prescribed during outpatient treatment. The changes in blood pressure, systemic hemodynamics, plasma renin activity, urine aldosterone, and glomerular filtration rate were evaluated. A significant and stable decrease in systolic and diastolic blood pressure associated with a fall in cardiac output (-21%), heart rate (-17%), plasma renin activity, and urine aldosterone were observed. The blood pressure lowering effect was unrelated to the decrease in cardiac output and plasma renin activity. Glomerular filtration rate was unchanged. No important side effects were observed during the treatment.

Adult↗
PubMed1983

Early dietary protein and phosphorus restriction is effective in delaying progression of chronic renal failure.

A diet containing about 40 kcal/kg, 0.6 g/kg of protein, 700 mg of phosphorus, and 1,000 to 1,500 mg of calcium (orally supplemented) was prescribed to three groups of patients with chronic renal failure for 6 to 76 months. The mean serum creatinine values were 2.18 mg/dl in group 1 (25 patients), 4.24 mg/dl in group 2 (20 patients), and 6.10 mg/dl in group 3 (8 patients). An additional group of 30 patients (group 4) who had followed no specific dietary treatment for 3 to 72 months was taken as control. The plots of reciprocal serum creatinine against time gave slopes of -0.0008, -0.0010, and -0.0041 in the three groups of patients on the protein-restricted diet, and a slope of -0.020 in the patients on the free diet. The differences between the slopes in patients in groups 1, 2, and 3 versus that in patients in group 4 are statistically significant (analysis of variance and F ratio: P less than 0.01). During the follow-up period a decline in reciprocal serum creatinine greater than the mean values in the whole group was observed in 37.5% of patients in group 3, in 20% of those in group 2, and in only 12% of those in group 1. Thus, the degree of functional renal deterioration is critical in modulating the effects of dietary protein and phosphorus restriction. Several nonimmunologic factors, including hypertension, infection, electrolyte abnormalities, and low-calorie intake, appeared to play an important role in influencing the rate of progression of renal failure in patients on dietary protein restriction.

Adolescent↗
PubMed1982

Changes of cerebral density in dialyzed patients.

CT studies were made on 38 patients receiving different dialytic treatment, 10 patients with chronic renal failure not yet dialyzed, and 15 healthy subjects. No morphological modifications were observed. On the contrary, significant changes of density were demonstrated after a dialysis session in the population treated intermittently. In these patients the density values were similar to those registered in the controls 1-6 h after a dialysis session. End stage renal failure and CAPD patients always had normal density values. Therefore cerebral density changes are caused only by the intermittent dialytic treatment.

Absorptiometry, Photon↗