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Biomedical subjects

U Alon

Publications and source records attributed to U Alon.

At least 91 records · Page 5Linked to original sources
PubMed1987

Polycystic kidneys as the presenting feature of tuberous sclerosis.

Tuberous sclerosis is an inherited neurocutaneous disorder characterized by seizures, mental retardation, cutaneous lesions and visceral hamartomas. We describe a 17-year-old boy in whom polycystic kidneys of the adult type were fortuitously detected on routine check-up. The patient enjoyed good health and had no evidence of renal dysfunction. Closer scrutiny of his past history and his physical and laboratory findings disclosed that he had tuberous sclerosis. Our case adds to the scant reported experience with the association of tuberous sclerosis and adult-type polycystic kidneys, and suggests that a search of additional manifestations of tuberous sclerosis is warranted in children in whom adult-type polycystic renal disease is detected.

Adolescent↗
PubMed1986

Effects of nonischemic hypoxia on jejunal mucosal structure and function: study of an experimental model in dogs.

A model of nonischemic hypoxia of the jejunum was designed in dogs, by shunting of blood from the inferior vena cava directly into the regional mesenteric arterial supply, thereby lowering the PaO2 of the blood that reached the jejunal wall from 98.6 +/- 3 to 62 +/- 5 mm Hg. Absorption rates of sodium, glucose, fructose, glycine, and the dibasic aminoacid lysine were studied by in situ luminal perfusion of a 30-cm proximal jejunal segment with a bicarbonate buffer solution containing phenol red as a nonabsorbable marker for determination of water fluxes. During periods of control, hypoxia, and after discontinuation of the venoarterial admixture (recovery), effluent perfusate was collected and mucosal biopsies were obtained for assay of lactase, maltase and sucrase activity, mucosal ATPase activity and ATP content, and for light- and electron microscopic examination. Mesenteric supply with hypoxic blood was associated with a significant inhibition of Na+,K+-ATPase activity (p less than 0.001) and a rise in mucosal ATP content (p less than 0.05). There was a significant reduction in the absorption rates of sodium (p less than 0.001), glucose, and glycine (p less than 0.01), but no change in the transport of fructose and of lysine. Brush border enzymes were unaltered. The histological appearance of the mucosa remained normal throughout the experiment, but on electron microscopy a distinct swelling of the enterocyte mitochondria was noted during the hypoxia period.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphatases↗
PubMed1986

Ultrasonography in the radiologic evaluation of children with urinary tract infection.

A prospective blind study comparing the findings of ultrasonography, intravenous pyelography, and voiding cystourethrography was conducted on 81 patients to examine the place of ultrasonography in the initial radiologic evaluation of children with urinary tract infection. The patients' mean age was 4.8 years; 15 were male. Forty-eight were inpatients (mean age, 3.2 years) and 33 were outpatients (mean age 7.2 years). In 29 patients (35.8%) abnormality of the urinary system was detected by one or more of the three imaging procedures; 21 were inpatients and eight were outpatients. The most frequent finding was vesicoureteral reflux, occurring in 62.1% of the pathologic cases. The findings at ultrasonography correlated well with those of intravenous pyelography in 73 of the 81 studies (90.1%), but they failed to demonstrate double collecting systems and several of the minor changes. However, ultrasonography in combination with cystourethrography identified all patients who had abnormal urinary systems, except for two children with negligible findings. Moreover, ultrasonography and cystourethrography together identified all 11 patients, nine of them inpatients, in whom surgical treatment was indicated. It is concluded that ultrasonography can successfully replace intravenous pyelography as a screening imaging procedure for the urinary system, but because of the superiority of intravenous pyelography in the detection of some types of lesions, intravenous pyelography will be required whenever ultrasonography or cystourethrography results are abnormal.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1986

Oral calcium carbonate as phosphate-binder in infants and children with chronic renal failure.

In view of the known toxicity of aluminum, we studied the effects of CaCO3 as an alternative phosphate binder in 12 chronic renal failure (CRF) children during 152 patient-months. Mean (+/- SD) serum creatinine concentration rose during that period from 3.7 +/- 1.8 to 5.1 +/- 3.0 mg/dl. 8 patients received CaCO3 from the start, and 4 were switched from A1(OH)3 after 2 months of interruption. In addition to CaCO3 (0.1-0.3 mg/kg BW) all patients received NaHCO3, and all but two received 1 alpha-hydroxyvitamin D3 [1 alpha(OH)D3] or dihydrotachysterol (DHT). Urine and blood variables were checked every 4-6 weeks and medication dosages were adjusted accordingly, aiming to keep serum Ca at 10.4-10.8 mg/dl, serum Pi at 3.5-5.5 mg/dl, and serum HCO-3 above 18 mEq/l. Bone X-rays were obtained every 6-9 months. With treatment, mean serum Ca increased from 8.9 +/- 0.7 to 10.3 +/- 0.4 mg/dl (p less than 0.01), serum Pi decreased from 6.3 +/- 0.9 to 4.2 +/- 0.5 mg/dl (p less than 0.01), and the mean Ca X P product decreased slightly and insignificantly. Mean serum alkaline phosphatase levels decreased significantly from 486 +/- 251 to 168 +/- 28 IU (p less than 0.01). Bone X-rays at the end of the study showed either healing of renal osteodystrophy or its prevention. Only one episode of mild hypercalcemia (serum Ca 11.7 mg/dl) was observed in 1 patient, but his Ca X P product remained low.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1985

Hydrochlorothiazide-amiloride in the treatment of congenital nephrogenic diabetes insipidus.

The effects of treatment with hydrochlorothiazide combined with amiloride were compared to hydrochlorothiazide treatment alone in 2 brothers with congenital nephrogenic diabetes insipidus. Whereas both modalities of treatment resulted in reduction in voiding frequency and urine volume, decrease in daily fluid intake and increase in urine osmolality, the two-drug combination was found to be superior to hydrochlorothiazide alone by preventing urinary potassium losses, hypokalemia, and alkalosis. It was also found that amiloride had a certain additive effect to the thiazide in terms of increasing initial urinary sodium excretion, reducing urine volume and free water clearance, and lowering serum sodium concentration and osmolality. Similar comparison of the hydrochlorothiazide-amiloride regimen to treatment with the hydrochlorothiazide-tolmetin combination in 1 of the patients revealed that the effectiveness of both diuretic modalities was close with slight advantage of the former. Treatment of the 2 patients for 10 months with hydrochlorothiazide and amiloride showed no adverse effects and consistent reduction in fluid intake and urine volume. It is concluded that the hydrochlorothiazide-amiloride regimen is superior to hydrochlorothiazide alone and can be a satisfactory alternative to the hydrochlorothiazide-prostaglandin synthetase inhibitor combination in the treatment of congenital nephrogenic diabetes insipidus.

Adult↗
PubMed1985

Effects of hydrochlorothiazide and amiloride in renal hypophosphatemic rickets.

The effects of thiazide diuretics on serum phosphate concentration, renal tubular threshold for phosphate, and urinary calcium excretion in children with renal hypophosphatemic rickets were studied. There were nine controlled acute studies conducted in five patients, and, in addition, seven long-term studies of up to 26 months were performed. During the acute studies, the children continued to receive the same doses of oral calcitriol and phosphate supplementation as at home. Hydrochlorothiazide, 1.50 to 2.25 mg/kg/d, was used alone in the first four studies; hydrochlorothiazide and amiloride at a dose of 1 mg for each 5 mg of hydrochlorothiazide were used in the other five studies. Administration of the diuretics for four days gave rise to a significant increase in serum phosphate concentration from 3.1 +/- 0.4 mg/dL to 3.7 +/- 0.9 mg/dL (P less than .01) and in tubular threshold for phosphate from 1.31 +/- 0.45 mg/dL to 1.74 +/- 0.60 mg/dL (P less than .01). These changes were accompanied by significant reductions in urinary sodium excretion from 135 +/- 39 mEq/24 h during the control period to 99 +/- 42 mEq/24 h on the fourth day of therapy (P less than .05), fractional sodium excretion from 0.99% +/- 0.42% to 0.81% +/- 0.42% (P less than .05), and urinary calcium excretion from 57.3 +/- 28.9 mg/24 h to 19.0 +/- 13.1 mg/24 h (P less than .01). Fractional excretion of phosphate divided by fractional excretion of sodium after the treatment with diuretics was not significantly different from that observed at the end of the control period. Increments in serum phosphate concentrations were correlated with elevations in serum albumin concentrations (r = .739; P less than .02). As an additional index of intravascular volume contraction, the elevations in serum phosphate concentrations were correlated with the increase in BUN, (r = .793; P less than .01). The addition of amiloride in the last five studies prevented the hypokalemia and alkalosis that had complicated the administration of hydrochlorothiazide. Long-term follow-up studies for a total of 119 therapy-months on six children and one adult, who continued to receive the diuretics concomitantly with calcitriol and phosphate supplementation, showed that they were free of complications except for a transient episode of hypercalcemia and hypercalciuria in one patient. In comparison with the previous period of treatment with calcitriol and phosphate without diuretics, linear growth velocity and healing of the rickets were not changed in two children and improved in the other four after the addition of hydrochlorothiazide and amiloride.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1985

Progressive diaphyseal dysplasia: evaluation of corticosteroid therapy.

Progressive diaphyseal dysplasia is characterized clinically by crippling leg pain, fatigue, headache, poor appetite, muscle weakness, and waddling gait. Twelve affected patients, aged 2 years 4 months to 40 years, were treated with intermittent courses of low doses of prednisone given in a single dose on alternate mornings for periods ranging from 6 months to 10 years. The average initial dose of prednisone was 0.6 mg/kg/d, and average maintenance dose was 0.3 mg/kg/d. Relief of all crippling symptoms was achieved in all patients. No untoward serious side effects have been observed, and the growth of children was not slowed. However, corticosteroid therapy should be restricted to patients suffering from crippling pain. The mechanism through which steroids act remains undefined.

Adolescent↗
PubMed1985

Hydrochlorothiazide, amiloride and tolmetin in the treatment of diabetes insipidus of Brattleboro rats.

To test the effects of hydrochlorothiazide (HCTZ) alone and in combination with amiloride or tolmetin in the treatment of nephrogenic diabetes insipidus, metabolic studies of 12 days each were carried out in 36 male, Brattleboro rats. They were divided into five groups as follows: (A) controls; (B) high dose HCTZ at 6 mg/rat/day; (C) low dose HCTZ at 3 mg/rat/day; (D) HCTZ identical to (C) but with addition of amiloride at 0.6 mg/rat/day; (E) HCTZ identical to (C) but with addition of tolmetin at 40 mg/rat/day. The immediate response to treatment was a significant increase in urinary sodium excretion from mean values (mEq/kg/day) of less than 11 to values higher than 13, except group E with mean value of 12. There was marked increase in urinary potassium excretion (mEq/kg/day), from mean control value of 15.5 to 21.5, 20.8, 18.5 and 17.7 in groups B, C, D and E, respectively. During the last three days of the study, mean urine osmolality (Uosm) and free water reabsorption (TCH2O) increased significantly: [formula: see text]. These indices were higher in groups B, D and E than in group C. Serum osmolality decreased only in groups B, C and D but not in the HCTZ-tolmetin groups. Similarly, serum sodium concentration was significantly lower in groups B, C and D compared to the control and the HCTZ-tolmetin groups. Serum potassium concentration was reduced in all the treated groups, but in both the groups treated with HCTZ-amiloride and HCTZ-tolmetin, the reduction was smaller than the one observed in the high-HCTZ treated group.(ABSTRACT TRUNCATED AT 250 WORDS)

Amiloride↗
PubMed1985

Muscle involvement in progressive diaphyseal dysplasia.

Muscle involvement in progressive diaphyseal dysplasia was evaluated in five children, of whom four were members of one family. Age range was 2 to 10 years 9 months, and mean age was 5.5 years. Evaluation included serum enzymes, electromyography, and muscle biopsy examined by light and electron microscopy. Serum enzymes were usually noncontributory. Electromyography revealed "myopathic pattern" in four of the five patients. Muscle biopsy specimens were taken from three of the five children, including two patients from one family, of whom one had normal electromyography, and one sporadic case. Examination of the biopsy specimens by light microscope was generally not useful, whereas electron microscopic examination revealed myopathic and vascular changes consisting of atrophy of isolated muscle fibers, accumulation of endomysial collagen fibrils, and thickening of the perivascular basement membrane. The main contribution of this study is to describe electron microscopic vascular changes in muscles that appear to be similar in familial and sporadic cases of progressive diaphyseal dysplasia.

Aspartate Aminotransferases↗
PubMed1984

Hemolytic-uremic syndrome associated with Streptococcus pneumoniae. Report of a case and review of the literature.

A child aged 2 years 3 months with Streptococcus pneumoniae sepsis and pulmonary abscesses had hemolytic-uremic syndrome and acute renal failure develop that required 36 cycles of peritoneal dialysis. A percutaneous renal biopsy specimen taken after dialysis showed mesangial proliferation with interposition, hemorrhagic crescents, and intracapillary thrombosis with fibrinogen and IgM deposition. The atrophic renal tubules showed positive immunofluorescence against peanut agglutinin. Neuraminidase released by pneumococcal organisms is thought to expose the Thomsen-Friedenreich antigen on platelets, erythrocytes, and kidneys, resulting in IgM deposition and binding of peanut agglutinin. Review of the literature showed four other reports involving five children who had hemolytic-uremic syndrome develop secondary to pneumococcal infections.

Acute Kidney Injury↗
PubMed1984

Renal tubular acidosis type 4 in neonatal unilateral kidney diseases.

Three neonates, two with unilateral renal vein thrombosis and one with unilateral dysplastic kidney, developed type 4 renal tubular acidosis, manifested by nonazotemic hyperkalemic metabolic acidosis with alkaline urine pH and reduced potassium excretion. Normal plasma concentrations of sodium, aldosterone, and renin activity, together with normal renal fractional excretion of sodium, supported the diagnosis of renal tubular acidosis type 4, subtype 5. Arginine HCl loading studies showed that despite their ability to bring the urine pH to less than 5.8, net acid excretion was inadequate relative to the corresponding plasma bicarbonate concentration. Treatment with oral bicarbonate resulted in sustained normalization of blood acid-base status and accelerated linear growth in the first two infants, in whom spontaneous recovery occurred by ages 8 and 15 months, respectively. At that time, the affected kidneys were extremely small with distorted collecting systems; the contralateral kidneys showed compensatory hypertrophy. In the third infant, persistent acidosis and growth failure resulted from medical noncompliance; the removal of the dysplastic kidney at 7 months of age was followed by the return to normal blood acid-base status and normalized tubular hydrogen and potassium excretion. We conclude that neonatal unilateral kidney disease can result in renal tubular subtype 5. Spontaneous recovery can be expected, presumably because of " autonephrectomy " of the affected kidney plus the compensatory hypertrophy of the contralateral kidney.

Acidosis, Renal Tubular↗
PubMed1984

Pneumococcal meningitis following parenteral alimentation in infants.

Three young infants with protracted diarrhea and malnutrition were successfully treated by means of intravenous nutrition, which included infusions of fat emulsion (Intralipid) and of fresh frozen plasma. Three to five weeks after termination of intravenous feeding, and after full recovery, they developed pneumococcal septicemia and meningitis. One infant died, and postmortem examination showed diffuse deposition of "intravenous fat pigment" in hepatocytes and in reticuloendothelial cells. In the two infants who recovered, follow-up studies did not disclose any primary derangement of immunologic function. We propose that the infused fat may have caused a temporary depression of immunologic defense mechanisms, predisposing these infants to the pneumococcal infection; the delay in onset of the infection might be attributed to a short-lasting protective effect of fresh frozen plasma which was included in the intravenous feeding regimen.

Blood↗