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Biomedical subjects

A Vallo

Publications and source records attributed to A Vallo.

At least 55 records · Page 3Linked to original sources
PubMed1986

Immunoglobulin-producing cells in IgA nephropathy.

The number of peripheral blood mononuclear cells (PBMC) producing IgA, IgG and IgM spontaneously, after in vitro polyclonal stimulation with pokeweek mitogen (PWM) and in response to autologous mixed lymphocyte reaction (AMLR), were determined by a protein A hemolytic plaque assay in 23 patients with IgA nephropathy confirmed by renal biopsies and in 24 normal controls. The geometric mean of circulating IgA-producing cells in Berger's disease (689 +/- 1.73 cells/10(6) PBMC) was increased when compared with the normal controls (332 X divided by 1.52 cells/10(6) PBMC; p less than 0.001). To a lesser degree, there was also an increase in the number of IgG-secreting cells (98 +/- 3.97 cells/10(6) PBMC vs. 38 +/- 2.90 cells/10(6) PBMC; p less than 0.05). After PWM stimulation, although the number of IgA-producing cells was increased in patients with IgA nephropathy, no significant differences were observed between the 2 groups. In response to AMLR, the number of IgA-secreting cells was significantly higher in the cases with Berger's disease (1,979 +/- 1.76 cells/10(6) non-T cells vs. 783 +/- 1.95 cells/10(6) non-T cells; p less than 0.001). Although it did not reach statistical significance, the patient group had also an increase in the number of IgG-producing cells (884 +/- 2.64 cells/10(6) non-T cells vs. 317 +/- 5.05 cells/10(6) non-T cells). These data support the existence of some abnormalities in the mechanisms regulating the synthesis of IgA in Berger's disease which might contribute to its pathogenesis.

Adolescent↗
PubMed1985

[Echography in the diagnosis on childhood nephrocalcinosis. Apropos of 5 cases].

We have studied 5 patients with nephrocalcinosis by means of plain film and sonography. Our results, which are in agreement with other authors, show that it is possible to find nephocalcinosis with no findings in the plain film. We correlate both examinations and propose a new radiologic approach for this condition.

Child↗
PubMed1984

Oral phosphate-loading test for the assessment of distal urinary acidification in children.

Neutral phosphate infusion results in an elevated urinary minus blood PCO2 gradient (U-B PCO2), providing that the urinary pH is close to the pK (6.8) of the phosphate buffer system. The present investigation was designed to evaluate whether an oral phosphate load could achieve similar results in children. 18 normal children, aged 3-13 years, were studied. Following the oral phosphate load, the urinary phosphate concentration increased to 44.8 +/- 4.7 mmol/l (mean +/- SEM), and U-B PCO2 reached 68.8 +/- 7.0 mm Hg, with a urinary pH of 6.87 +/- 0.07. With a urinary phosphate concentration above 20 mmol/l, all children reached a U-B PCO2 above 40 mm Hg. 4 children with primary distal renal tubular acidosis were also studied. All exhibited a U-B PCO2 below 20 mm Hg despite values of urinary phosphate concentration at or above 20 mmol/l, indicating the presence of a true secretory defect in distal hydrogen ion secretion. The present study demonstrates that an oral phosphate load is as effective as a phosphate infusion in elevating the urinary PCO2 and, therefore, could have a wide application in the pathophysiologic evaluation of renal tubular acidosis.

Acidosis, Renal Tubular↗
PubMed1983

Biochemical features of dietary chloride deficiency syndrome: a comparative study of 30 cases.

The diagnosis in one infant of a severe state of chloride deficiency after ingesting a diet consisting exclusively of a modified cow milk formula containing only 0.5 mEq/100 kcal chloride ion led to the identification of 30 additional infants (age 2.6 +/- 0.7 months) fed the same commercial formula. The total absence of chloride in the urine was used as a biochemical index of subclinical dietary chloride deficiency. Serum and urine values were studied at diagnosis and 10 to 12 days after chloride replenishment, and compared statistically with the values obtained in a control group of 40 infants (age 2.8 +/- 1.2 months) fed exclusively a different modified formula containing an adequate chloride concentration. The outstanding laboratory abnormalities noted in the infants ingesting a low chloride formula were hypochloremia and metabolic alkalosis. Mean serum concentrations of potassium, urea, creatinine, and uric acid were in the normal range, but group values were statistically different from normal. A previously unreported finding was the demonstration of a significant elevation in the serum concentrations of calcium and phosphate and in the urinary excretions of calcium and magnesium, which persisted after almost complete recovery of the remaining biochemical disturbances. These results indicate the potential risk of nephrocalcinosis after dietary chloride deficiency.

Calcium↗
PubMed1983

Transient pseudohypoaldosteronism secondary to obstructive uropathy in infancy.

A syndrome of renal tubular resistance to aldosterone has been identified in infants with obstructive uropathy and urinary tract infection. Six infants (ages 9 days to 7 months) were seen with fever, vomiting, polyuria, dehydration, or failure to thrive. Urine cultures were positive for Escherichia coli. Radiologic studies demonstrated bilateral ureterohydronephrosis (four patients), left ureteral duplication with upper pole hydronephrosis (one), and left vesicoureteral reflux (one). The infants had hyponatremia, hyperkalemia, and metabolic acidosis. Plasma aldosterone concentration was markedly elevated, and plasma renin activity was similar to or higher than that reported in normal infants of comparable age. Fractional excretion of potassium was not significantly different from control values, both in absolute terms or when related to glomerular filtration rate, but fractional sodium excretion was significantly increased. The UK/UNa ratio was significantly lower in the patients. After medical or surgical therapy (when appropriate), all blood and urine determinations returned to normal, except for UK/UNa values, which although higher, remained significantly diminished. Our data indicate that a hyperkalemic salt-losing state can arise in infants with obstructive uropathy and urinary tract infection as a consequence of tubular unresponsiveness to aldosterone, and that the clinician should rule out such cause before establishing the diagnosis of primary pseudohypoaldosteronism.

Aldosterone↗
PubMed1983

Renal handling of sodium in premature and full-term neonates: a study using clearance methods during water diuresis.

A study using fractional clearances during orally induced water diuresis was designed to delineate the mechanism underlying defective tubular reabsorption of sodium in very low-birth-weight neonates. The use of clearance methodology during maximal water diuresis may give an indirect estimate of distal sodium delivery [urine volume (V), CH2O + CNa + K], sodium reabsorption at the diluting segments (CH2O), and proportion of the distal load reabsorbed distally (CH2O/CH2O + CNa + K), when all values are corrected to 100 ml glomerular filtration rate. The study was carried out in 28 healthy newborn infants who were grouped according to conceptual age (CA): 13 infants with mean birth weight of 1370 +/- 330 g and mean CA of 31.8 wk (range, 28-34 wk), and 15 infants with mean birth weight of 2330 +/- 550 g and mean CA of 37.9 wk (range, 35-41 wk). All studies were performed at 6-7 days of age. It was demonstrated that higher urinary osmolality (67.5 +/- 23.2 versus 52.9 +/- 9.4 mOsm/kg, P less than 0.0025) and higher fractional sodium excretion (2.3 +/- 1.8 versus 0.9 +/- 0.5 ml/dl glomerular filtration, P less than 0.01) observed in the group of very preterm infants resulted from significantly decreased proximal (V: 18.7 +/- 6.0 versus 13.3 +/- 3.6 ml/dl glomerular filtration, P less than 0.005; CH2O + CNa + K: 17.1 +/- 5.2 versus 11.9 +/- 3.3 ml/dl glomerular filtration, P less than 0.005) and distal (CH2O/CH2O + CNa + K X 100: 81.9 +/- 8.2 versus 88.2 +/- 4.5%, P less than 0.01) tubular sodium reabsorption.(ABSTRACT TRUNCATED AT 250 WORDS)

Diuresis↗
PubMed1983

[Isolated isoleucine deficiency in diet therapy of a case of maple syrup urine disease].

A case of maple syrup urine disease is described presenting during diet therapy a clinical picture with predominant cutaneous symptoms attributed to a dietary deficiency. It is believed that probable cause was the coexistence of low serum levels of isoleucine with still elevated levels of leucine. Given the metabolic interrelationship existing between different branch-chained amino acids, an independent dietary correction of each amino acid is recommended.

Acrodermatitis↗
PubMed1982

Natural history of primary distal renal tubular acidosis treated since infancy.

Clinical and pathophysiologic studies were performed in five unrelated children with primary distal renal tubular acidosis who were diagnosed during infancy and followed for 3 to 9 1/2 years. All patients had permanent defects in hydrogen ion secretion, sodium reabsorption, and concentrating capacity. A transient, age-related, proximal tubular defect in sodium and bicarbonate reabsorption was also present. Renal bicarbonate wasting was mainly observed during the first years of life and progressively decreased with advancing age. Glomerular filtration rate remained within normal limits. Following sustained therapy with sodium and potassium bicarbonate, the patients had optimal growth, arrest of progression of nephrocalcinosis, and lack of other characteristic features of the disease with the exception of polyuria. Dosage of alkali was mainly determined by the magnitude of the renal bicarbonate loss and decreased progressively from a maximum of 3.9 to 10.0 mEq/kg/day during the first year of life to about 3 mEq/kg/day at or beyond 6 years of age. The total dosage of alkali required could be derived by the sum of the urinary excretion of bicarbonate plus 2 mEq/kg/day, which represents mean endogenous acid production. Although calciuria was normal when metabolic acidosis was corrected, patients with higher urinary sodium excretion had higher urinary excretion of calcium and thus were at greater risk of developing nephrocalcinosis if therapy was not carefully controlled.

Acidosis, Renal Tubular↗
PubMed1982

Defect in urinary acidification in nephrotic syndrome and its correction by furosemide.

6 children with idiopathic nephrotic syndrome were investigated during clinical relapse to examine the interrelation between distal urinary acidification and urinary sodium excretion. Blood and urine studies were initiated 4 h after completion of ammonium chloride loading, prior to and following the intravenous administration of furosemide. Values for plasma bicarbonate before and after furosemide administration were not significantly different. In the control periods, when urinary sodium excretion was very low, a defect in urinary acidification was demonstrated (UPH: 6.09 +/- (SD) 0.27; UTAV and UNH4V: 12.6 +/- 3.1 and 36.4 +/- 15.8 mumol/min/1.73 m2, respectively.) Following furosemide-induced natriuresis UPH fell to 4.81 +/- 0.25 (p less than 0.0005), and UTA2V and UNH4V increased to 46.3 +/- 15.8 and 125.6 +/- 49.5 mumol/min/1.73 m2, respectively (p less than 0.002). No overall correlation existed between urinary acidity, both considered as hydrogen ion concentration and as hydrogen ion excretion, and rate of urinary sodium excretion; but significant correlations were present between hydrogen ion concentration in the urine and both UC1V-UNAV (r = 0.38, p less than 0.05), and UC1V - (UNaV + UKV) (r = 0.64, p less than 0.01). These results indicate that the defect in distal urinary acidification observed in nephrotic syndrome is probably due to decreased delivery of sodium to the distal nephron. The enhanced secretion of hydrogen ion observed after furosemide administration may be related both to increased sodium delivery and to greater sodium than chloride reabsorption in the collecting duct.

Child↗
PubMed1982

[Combined exchange transfusion and peritoneal dialysis treatment in a neonatal case of methylmalonic acidemia with severe hyperammonemia].

A case of methyl-malonic acidemia with severe neonatal hyperammoniemia is presented. Treatment during the first days of live with exchange-transfusion, with protein-free blood and peritoneal dialysis induced a decrease of blood ammonia values from 1360 to 270 micrograms/dl and the correction of systemic metabolic acidosis. Continuation of treatment by dietary means was followed by normalization of clinical status and almost total correction of the urinary excretion of methyl-malonic and propionic acids, but the patient died at 33 days of life due to an intercurrent infection. This case, together with a case previously reported of propionic acidemia with neonatal hyperammoniemia and prolonged survival, demonstrates that complementary treatment by means of exchange transfusion and peritoneal dialysis is mandatory in all cases of neonatal hyperammoniemia of metabolic origin, since survival without irreversible neurological damage is possible.

Amino Acid Metabolism, Inborn Errors↗
PubMed1982

Different functional characteristics of residual nephrons in infantile vs adult diffuse cortical necrosis.

In this report we study the functional characteristics of residual nephrons in a 37 year-old woman, 7 months after diffuse bilateral cortical necrosis (CN) of unknown etiology, and in two infants, aged 13 and 15 months, who suffered CN in early infancy after surgical shock and acute dehydration, respectively. In the three cases CN was proven histologically by renal biopsy but undamaged nephrons were only present in the juxtamedullary area in the adult patient whereas in the two infants they were located in the outer part of the cortex. At the time of the study all patients presented a similar degree of renal insufficiency (creatinine clearance: 17-23 ml/min/1.37 m2). The adult patient showed a partly conserved ability to concentrate the urine, a marked free water formation in relation to the degree of distal sodium delivery and an unimpaired capacity to acidify the urine after an acid load. Both infants, by the contrary, were unable to concentrate the urine, had lower free water formation at similar rates of distal sodium delivery and presented a clear incapacity to acidify the urine. These results confirm previous finding indicating the sparing of juxtamedullary nephrons after CN in the adult subject but favor the existence of a surviving population of superficial nephron when CN occurs in early infancy. These differences are probably in relation with associated damage of deep cortex and medulla infancy due to the specific characteristics of blood flow distribution present at that age.

Acute Kidney Injury↗
PubMed1980

Renal handling of water and sodium in children with proximal and distal renal tabular acidosis.

Renal sodium wasting has been observed in both proximal and distal renal tubular acidosis (RTA), although few studies have been reported indicating the tubular localization of such a defect. The use of clearance methodology during hypotonic saline diuresis may give an indirect estimate of proximal tubular reabsorption of sodium, sodium reabsorption at the diluting segments and proportion of sodium load reabsorbed distally. This study was carried out in 17 normal children, in 9 children with proximal RTA, associated in all but one with the Fanconi syndrome, and in 5 children with primary distal RTA. Patients with proximal RTA presented mainly an impaired reabsorption of sodium in the proximal tubule, which was in great part but not completely compensated by an absolute increase in distal sodium reabsorption. Patients with distal RTA showed normal reabsorption of sodium in the proximal tubule but they were unable to reabsorb completely the load of sodium escaping proximal reabsorption due to a defect of sodium reabsorption in the distal diluting segments. These results indicate that the classification of RTA in proximal and distal types is also valid according to the differences found in the tubular handling of water and sodium.

Acidosis, Renal Tubular↗
PubMed1978

Juvenile cirrhosis and membranous glomerulonephritis in a child with alpha1-antitrypsin deficiency PiSZ.

An infant with alpha1-antitrypsin (alpha1-AT) deficiency PiSZ presented with liver cirrhosis and showed clinical and laboratory evidence of renal disease when hepatic decompensation developed, shortly before death at 12 months of age. Low serum levels of alpha1-AT were only demonstrated late in the disease. SZ phenotype was proved by starch gel electrophoresis. Post-mortem pathological studies revealed severe hepatic cirrhosis with intracytoplasmic inclusion of alpha1-AT and membranous glomerulonephritis with deposits of complement and immunoglobulins but without the presence of alpha1-AT. The present case suggests the importance of studying Pi phenotypes and serum levels of alpha1-AT in all cases of idiopathic cirrhosis or renal disease in infancy.

Electrophoresis, Starch Gel↗
PubMed1978

Proximal renal tubular acidosis in metachromatic leukodystrophy.

A 2-year-old girl affected with the late infantile form of metachromatic leukodystrophy had a persistent and moderate metabolic acidosis. Renal functional studies demonstrated the presence of decreased tubular reabsorption of sodium, bicarbonate and some amino acids. Other tubular functions, including distal urinary acidification and concentrating mechanism were normal. Glomerular filtration rate was moderately decreased. Metachromatic inclusions were demonstrated along the nephron by histochemistry and electron microscopy. Tubular dysfunction in metachromatic leukodystrophy could have been overlooked until now given the severity of the neurological picture.

Acidosis, Renal Tubular↗
PubMed1978

[Ketotic hiperglycinemia: one case of possible propionic acidemia (author's transl)].

Authors present the first case to be observed in Spain of neonatal propionic acidemia. The subject is a newborn with symtoms free interval, family consanquinity and siblings who have died prematurely with a similar picture of hyperventilation "sine materiae", progressive metabolic acidosis without anionic discrepancy and terminal coma. The possibility that it might be a question of other metabolopathies is under discussion, but bio-chemical examination, with discovery of large quantities of propionic acid in urine (51 mcg./ml.) and concentrations of aminoacids in plasma, strongly suggest the diagnosis of a new case of neonatal propionic acidemia.

Amino Acids↗