PubMed Health⌕ Search

Biomedical subjects

F B Stapleton

Publications and source records attributed to F B Stapleton.

At least 91 records · Page 5Linked to original sources
PubMed1986

CT peritoneography in evaluation of pediatric dialysis complications.

Intraperitoneal contrast material with CT scanning was used to evaluate three children with multiple recurrences of peritonitis and no obvious source of infection while they were undergoing continuous-cycling peritoneal dialysis. In one child a loculus of uno-pacified dialysate was readily identified, confirming sonographic findings that suggested an inflammatory pseudocyst. In the other two children, contrast material dispersed throughout the peritoneal dialysate, suggesting that recurrent peritonitis occurred from extraperitoneal contamination. CT peritoneography is easily performed with contrast material instilled through the peritoneal dialysis catheter. Combining anatomic imaging with intraperitoneal-fluid dynamics, this technique should provide more complete evaluation of the peritoneal cavity than other imaging methods. While additional evaluation is necessary, our initial experience suggests the usefulness of CT peritoneography in excluding an intraperitoneal source of infection during long-term peritoneal dialysis.

Adolescent↗
PubMed1985

Low-renin hypertension in young infants.

Plasma renin activity (PRA) in neonates is significantly higher than in older infants and children and may increase as a result of numerous physiologic or therapeutic factors. For these reasons, the measurement of PRA is not usually helpful in establishing the cause of hypertension in neonates. In conditions that suppress renin release, however, measurement of PRA can be most useful. Herein, we describe two infants (ages 4 and 5 months, respectively) with sustained hypertension and low PRA secondary to dexamethasone-suppressible hyperaldosteronism. Low PRA was essential in establishing this diagnosis in both patients. Dexamethasone-suppressible hyperaldosteronism should be considered in hypertensive infants who have normal genitalia and low PRA.

Dexamethasone↗
PubMed1985

Increased urinary excretion of renal N-acetyl-beta-glucosaminidase in hypercalciuria.

Urinary excretion of N-acetyl-beta-glucosaminidase (NAG), a lysosomal enzyme, was examined in 33 children with hypercalciuria. Urinary NAG excretion in 13 healthy children was 5.84 +/- 9.35 nmole/hr/mg of creatinine (NAG/Cr) (mean +/- SD) compared with 35.61 +/- 42.04 nmole/hr/mg of creatinine in 23 children with renal hypercalciuria, and 28.99 +/- 13.69 nmole/hr/mg of creatinine in ten children with absorptive hypercalciuria. In children with renal hypercalciuria, NAG/Cr excretion was not statistically different between children with either urolithiasis or hematuria without calculi. In six children with renal hypercalciuria, no significant change in NAG/Cr excretion occurred after a mean duration of 25 weeks of hydrochlorothiazide therapy although urinary calcium to creatinine ratios (UCa/Cr) decreased from 0.24 +/- 0.11 to 0.16 +/- 0.11. We conclude that increased urinary calcium excretion produces renal tubular injury and that the renal injury may not be reversed by short-term alterations in urinary calcium excretion.

Adolescent↗
PubMed1985

Hypercalciuria in children with juvenile rheumatoid arthritis: association with hematuria.

After discovering juvenile rheumatoid arthritis (JRA), hematuria, and urolithiasis associated with hypercalciuria in two children, urinary calcium excretion was examined in 38 patients with JRA. Fasting urine calcium/creatinine (mg/mg) (UCa/UCr) ratios were increased (greater than 0.21) in 12 patients, who had a mean UCa/UCr ratio of 0.34 +/- 0.14, compared with 0.09 +/- 0.06 in 26 normocalciuric patients with JRA. Increased UCa/UCr ratios were found more frequently in patients with systemic JRA (P less than 0.05); however, no relationship between UCa/UCr ratios and either functional classification or drug therapy was observed. Four children with increased urine calcium to creatinine ratios were examined more extensively. Twenty-four-hour urine calcium excretion ranged from 4.0 to 7.2 mg/kg/24 hours. An orally administered calcium loading test demonstrated fasting hypercalciuria after dietary calcium restriction in these four patients. Serum calcium, bicarbonate, phosphorus, and parathyroid hormone values were normal. Hematuria was found in six of 12 hypercalciuric patients with JRA but in only three of 26 normocalciuric patients (P less than 0.016). We conclude that urinary calcium excretion is frequently increased in patients with JRA and that hypercalciuria may be related to the pathogenesis of hematuria in some of them.

Arthritis, Juvenile↗
PubMed1985

Neonatal hypertension from a unilateral multicystic dysplastic kidney.

Multicystic renal dysplasia is an extremely uncommon cause of hypertension in children and the few reported cases have not been of newborns. We report on a neonate in whom severe hypertension associated with elevated peripheral plasma renin resulted from a unilateral multicystic dysplastic kidney. Hypertension and plasma renin activity normalized after unilateral nephrectomy. No evidence of perfusion or excretory renal function in the dysplastic kidney was present on a radionuclide renal scan. This child demonstrates a relationship between hypertension and unilateral multicystic renal dysplasia.

Blood Pressure↗
PubMed1984

Hypercalciuria in children with hematuria.

Urinary calcium excretion was assessed in 83 consecutive children with gross or microscopic hematuria in whom the presence of proteinuria or urinary-tract infection had been excluded. Twenty-three children had hypercalciuria. Clinical features that were more commonly associated with hypercalciuria included gross hematuria and a family history of urolithiasis. No clinical or pathological basis for the hematuria was determined in 22 of the 23 children with hypercalciuria or in 38 of the 60 children with normal calcium excretion. Urolithiasis developed in two children with hypercalciuria during the period of study. Oral calcium-loading tests were performed in all 23 children with hypercalciuria. Absorptive hypercalciuria was demonstrated in 10 children, whereas 13 had renal (fasting) hypercalciuria. Hematuria resolved during anticalciuric therapy in 20 of the 23 patients with hypercalciuria. We conclude that determination of urinary calcium excretion is warranted in the routine evaluation of children with hematuria.

Adolescent↗
PubMed1984

Coarctation of the aorta and renal artery stenosis in tuberous sclerosis.

Among neurocutaneous disorders, coarctation of the abdominal aorta and renal artery stenosis have traditionally been associated with neurofibromatosis. We report a 5-year-old girl who, during the evaluation of asymptomatic hypertension, was discovered to have bilateral renal artery stenosis, coarctation of the abdominal aorta, renal cysts and typical skin lesions of tuberous sclerosis. Renal vascular hypertension has not been reported previously in tuberous sclerosis. We conclude that the tuberous sclerosis complex should be expanded to include vascular malformations and that hypertension should not be assumed to be secondary to renal hamartomata or cysts in patients with tuberous sclerosis.

Aortic Coarctation↗
PubMed1984

Urolithiasis in pre-term neonates associated with furosemide therapy.

The administration of furosemide to pre-term neonates has been associated with urolithiasis. We report 1 of 2 such cases that we have managed. The etiology of these stones appears to be related to furosemide-induced hypercalciuria. Nonsurgical management with thiazide diuretics can be successful in this high risk group of patients.

Bronchopulmonary Dysplasia↗
PubMed1984

Potential surgical implications of unexplained hematuria in children.

Hematuria in children can be secondary to hypercalciuria and may occur well before a clinical stone episode. We report on 9 patients with initially unexplained hematuria who proved subsequently to exhibit stone formation secondary to hypercalciuria. The evaluation of otherwise unexplained hematuria in children should include calcium excretion studies. Long-term followup of patients with hematuria secondary to hypercalciuria is necessary because of the potential development of surgically significant stone disease.

Calcium↗
PubMed1983

Infantile polycystic kidney disease: an imaging dilemma.

Infantile and adult type polycystic kidney diseases are 2 disparate genetic disorders and generally are easily distinguishable on the basis of clinical, pathologic, and radiologic findings. We present 3 children with infantile polycystic kidney disease, ages 9 months to 6 years, in whom the excretory urogram and/or renal ultrasound or gross anatomical appearance of the kidneys resembled adult polycystic kidney disease. The findings from these 3 patients emphasize the importance of renal and liver biopsies in the diagnosis of cystic kidney disease in young children.

Child↗
PubMed1983

Renal uric acid clearance in human neonates.

Renal clearance of uric acid was examined in 40 premature and term infants during the first 24 hours of life. Creatinine clearance and uric acid clearance increased with increasing gestational age. Serum uric acid concentration (r = -0.31, P less than 0.05) and fractional excretion of uric acid (r = -0.50, P less than 0.01) were inversely related to gestational age; FEUA was nearly 70% at 29 to 31 weeks gestational age, and decreased to a mean value of 39 +/- 14% (+/- SD) at 38 to 40 weeks gestational age. The decline in FEUA with advancing gestational age appears to represent alterations in net renal tubular transport of uric acid, because the filtered load of uric acid increased with gestational age. Postnatal clearance studies were performed in 18 premature infants of 29 to 35 weeks gestational age; FEUA also declined during early postnatal development (r = -0.44, P less than 0.01). In all studies, a relationship between FEUA and fractional excretion of sodium was observed. The high basal excretion of uric acid in infants may increase the risk of acute uric acid nephropathy when excretion demands are increased.

Female↗
PubMed1983

Clinical experience with pediatric urolithiasis.

Our clinical experience with 47 pediatric patients with stones is reviewed. Surgical therapy was standard with successful stone manipulation in 12 of 13 patients. In 91 per cent of our patients factors causing or predisposing to stone disease were discovered. A thorough metabolic evaluation, including an oral calcium loading test in 20 children, proved to be helpful. A new patient subgroup relating unexplained hematuria to eventual stone formation is described. Our protocol for metabolic evaluation and recommendations for treatment based on the results of such an evaluation are given. We have found the metabolic evaluation of the child with stones meaningful and particularly helpful in planning subsequent therapy for these patients.

Adolescent↗
PubMed1983

Ontogeny of hepatic peroxisomal uricase activity in the mongrel puppy.

Activities of uricase, catalase, and acid phosphatase were measured in the light mitochondrial subcellular fraction of liver from late fetal, neonatal, and adult dogs in order to examine the hypothesis that diminished hepatic peroxisomal uricase activity is responsible for elevated plasma uric acid concentrations in newborn puppies. Late fetal dogs had slightly lower uricase activity than 1-day-old puppies (1.4 +/- 1.0 (S.D.) and 3.9 +/- 0.7 X 10(-5) mumole hydrolyzed/min/g liver, respectively, P less than 0.5), and both were much lower than 30-day-old and adult dogs (46.3 +/- 33.7 and 30.8 +/- 17.6, respectively, P less than 0.50). Comparison with the pattern of development of catalase and acid phosphatase demonstrated nonparallelism with uricase activity lagging behind both other enzymes. Plasma urate concentrations of 0.66 +/- 0.09 (S.D.) mg/dl in fetal animals were higher than the maternal plasma value (0.22 mg/dl), which appears to exclude the possibility that low fetal uricase activity was the result of decreased enzyme substrate.

Acid Phosphatase↗