Biomedical subjects
Publications and source records attributed to A L Friedman.
We describe 3 sets of twins with discordance for urological malformations. Zygosity was documented by HLA and blood group typing. It is suggested that evaluation of the identical twin of an affected patient should include the entire urinary tract because of the potential for different lesions.
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Aortorenal vein fistula from trauma is a rare entity. A case is reported in which previous anterior abdominal attempts at repair rendered a thoracoabdominal approach necessary. Previous reports and techniques are compared and discussed.
Between 1975 and 1988, 92 pediatric patients have undergone bone marrow transplantation (BMT) at our institution for malignant or immune deficiency disease. We evaluated in a retrospective fashion 64 of these patients who survived beyond the first 60 days post-BMT. The clinical course was divided into: less than 60 days post-BMT (early) and greater than 60 days post-BMT (late). The presence or absence of renal insufficiency was noted as well as all known potential factors predisposing to insufficiency. Step-wise regression analysis was then performed to determine which of the factors were most significantly associated with renal dysfunction during the two periods. The follow-up period was 2 months to 11 years (mean 17.5 months). The mean age of the patients was 7.6 years (1 month-18 years). Fifty percent of the patients had renal insufficiency during the early period and 28% of the patients had insufficiency after the initial 60 days. Three major predictors of renal insufficiency were discovered. Cyclosporin A or amphotericin B early or late post-BMT was independently predictive of developing insufficiency during the same period. Conditioning with total body irradiation was a predictor for insufficiency in both periods. Early insufficiency was not predictive of late insufficiency. Hypertension was present in 31% of patients during the early period and in 16% during the late period. Hypertension was strongly associated with cyclosporin use and renal insufficiency. Renal insufficiency is a frequent sequela in children following BMT and likely results from a combination of radiation injury and drug toxicity.
In a prospective, controlled study, plasma and urinary taurine concentrations were determined weekly, between postnatal weeks 3 and 18, in (1) seven sick infants (gestational age less than 28 weeks, birth weight less than or equal to 1000 gm) who received a taurine-free total parenteral nutrition solution for 32 to 49 days (group P) and who subsequently were formula fed and (2) eight sick infants matched by gestational age and birth weight, who received formula or human milk from day 3 to 4 of life (group E). Ten healthy full-term infants ranging in age from 1 to 18 weeks and fed with formula provided normal values (group C). Significantly lower mean plasma taurine values (range 1.59 to 3.43 mumol/dl) were found between postnatal weeks 3 and 7 in group P compared with group E (range 5.54 to 6.97 mumol/dl) and with group C (5.6 +/- 0.34 mumol/dl). After initiation of feeding, plasma taurine concentrations in group P increased to normal. Markedly elevated values of mean fractional excretion of taurine, 38% to 56%, were found between weeks 3 and 5 in group P and E compared with group C (15.5 +/- 3.2%). In contrast, during the same period, low urinary taurine values (4.9% to 6.7%) were found in two larger, older infants receiving total parenteral nutrition whose plasma taurine values were in the normal range. After week 5, urinary taurine values were in the control range in all groups. We conclude that the absence of taurine in total parenteral nutrition solutions administered to very low birth weight infants and the limited ability of the immature kidney to adapt to low taurine intake by "up-regulation" of tubular taurine reabsorption may result in depleted taurine body pools during the first weeks of life. This inability to conserve taurine by the immature nephron could potentially have a deleterious effect on the developing brain and retina in these infants, and indicates a possible need for taurine supplementation.
This report describes the serum osteocalcin values in children with mild to moderate, but relatively stable, renal dysfunction followed in the Growth Failure in Children With Renal Diseases Study. This report is derived from data obtained during the control period (6 months) before the initiation of vitamin D therapy. Up to three measurements per patient were obtained. Serum osteocalcin concentration was compared with creatinine clearance (glomerular filtration rate) calculated by the Schwartz formula; with serum concentrations of alkaline phosphatase, parathyroid hormone, and bicarbonate; and with the percentages of the recommended dietary allowances of calories and protein ingested. By standard correlation techniques, there appeared to be an inverse correlation between calculated creatinine clearance and serum osteocalcin concentration, and a direct correlation between serum osteocalcin and parathyroid hormone values. However, when we employed a statistical technique that takes into account repeated measures in the same patient, no correlation was found between calculated glomerular filtration rate and serum osteocalcin concentration, and no direct correlation was found between serum osteocalcin and parathyroid hormone values. The lack of a correlation between calculated glomerular filtration rate and serum osteocalcin values may be due to large fluctuations in the serum osteocalcin concentration, even though renal function is relatively stable.
We report two cases from a family with primary Fanconi syndrome. A 39-year-old white woman with a history of frequent bone fractures developed hypophosphatemia, hypouricemia, hypokalemia, metabolic acidosis, and renal glycosuria. Her 15-year-old son had renal glycosuria without metabolic acidosis. Both had mildly to moderately impaired renal function. Determination of amino acids in 24-hour urine specimens confirmed the generalized nature of aminoaciduria. Acid-loading, bicarbonate-loading, and phosphate-loading tests revealed that the mother had proximal (type II) renal tubular acidosis and excessive renal loss of phosphate for her level of renal function. These tests for the son were normal or within normal limits of his renal function. Known causes of Fanconi syndrome, such as cystinosis and Wilson's disease, were excluded by slit-lamp eye examination and leukocyte cystine level determination. One unexpected finding in the son was the preseNce of nephrocalcinosis on x-rays; a percutaneous needle biopsy of the kidney showed tubular atrophy, interstitial fibrosis, and calcium oxalate crystal deposits. The two cases presented here represent a familial variety of the primary Fanconi syndrome, a rare entity with a limited number of cases reported in the literature.
The first step of chloroplast protein import is binding of a precursor protein to the surface of the organelle. Precursor binding for the small subunit of ribulose-1,5-bisphosphate carboxylase to isolated pea chloroplasts was investigated using a receptor-ligand binding assay. Translocation of precursors was blocked by conducting the binding assays at 0 degrees C. Binding of precursor was judged to be receptor mediated by the following criteria: (a) precursor binding was saturable at between 1500 and 3500 molecules per chloroplast; (b) binding is a high affinity interaction with a dissociation constant of 6 to 10 nanomoles; (c) binding is physiologically productive since most of the bound precursors could be imported from the bound state; and (d) precursor binding was sensitive to both protease and the sulfhydryl modifying reagent N-ethylmaleimide. The effects of these two reagents differed in that protease reduced the total number of binding sites from the surface of chloroplasts but had little effect on binding affinity, whereas N-ethylmaleimide reduced the binding affinity but had little or no effect on receptor density.
Using a model of unilateral nephrectomy and contralateral heminephrectomy in weanling rats, we studied the effect of severe (6%) and moderate (14%) protein restriction on growth and renal function up to 24 wk of age. One-half the normal (N) and chronic renal insufficiency (CRI) rats underwent a cross-over protocol 6%----14% and 14%----6% at 10wk of age to analyze the contribution of early growth on ultimate wt and length. N or CRI fed a 6% protein diet were the smallest. Animals switched from 6%----14% protein diet did not catch up to their counterparts started on a 14% protein diet (N or CRI). However, N or CRI animals started on a 14% protein diet and switched to a 6% protein diet grew along a curve similar to animals fed a 14% protein diet. Creatinine clearances for CRI rats were not different among the groups. However, protein excretion was highest in those animals completing the study on a 14% protein diet. Growth failure caused by severe protein restriction occurred primarily in the early accelerated growth phase (3-10 wk). We conclude that moderate protein restriction during the early rapid growth phase maintains growth, whereas severe protein restriction is detrimental to growth. Switching to a more restrictive protein intake after the rapid growth phase did appear to offer more renal protection (lower urinary protein excretion) at the end of 24 wk. Severe protein restriction to preserve renal function is a poor strategy for the young rapidly growing individual with chronic renal disease.
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A 21-yr-old postpartum woman was found to be hypocalcemic and hypomagnesemic with a normal serum immunoreactive parathormone level (hypomagnesemic hypoparathyroidism). She was treated with calcitriol, calcium and magnesium. Two yr later the patient's son presented with tetany, hypocalcemia and the physical changes of pseudohypoparathyroidism. Subsequently, the patient's niece and nephew were also diagnosed with pseudohypoparathyroidism (low serum calcium, high serum phosphorus, high circulating immunoreactive parathormone). Re-evaluation of the patient on the above medical therapy showed a normal serum calcium, phosphorus and magnesium levels and an abnormally high serum immunoreactive parathormone level. The patient's magnesium supplementation was discontinued. No change in serum calcium, magnesium or parathormone levels resulted. We think that this patient demonstrates that hypomagnesemia can mask the laboratory presentation of pseudohypoparathyroidism by suppressing secretion of parathormone and further demonstrates that in pseudohypoparathyroidism the parathyroid gland retains its physiologic response to hypomagnesemia.
A boy aged 4.5 years with prune-belly syndrome and associated urethral stenosis, oligohydramnios, imperforate anus and vesicosigmoid fistula is described. In contrast to the anticipated poor prognosis, vesicostomy and divided transverse colostomy performed after birth followed by prophylaxis of infection and bicarbonate supplementation have resulted in a good outcome. The vesicosigmoid fistula might have served in utero as a "natural diversion" protecting from pressure-induced renal damage. It is suggested that the main determinant of prognosis in PBS is the presence and degree of kidney dysplasia at birth as reflected by the neonatal renal function after performance of an indicated urinary diversion procedure rather than the presence of severe associated anomalies.
We report a case of long-term ureterosigmoidostomy in which acid base balance was monitored by electrolyte survey and bone density measurements. The pathophysiology of bony changes and its assessment by a radionuclide method are discussed.
Taurine is the major free intracellular amino acid. It has become the focus of study by many as a conjugator of bile and as a neurotransmitter and intracellular messenger. In this report we document a technique for measuring taurine in physiologic samples which is rapid, reproducible, and accurate. Any physiologic sample is first derivatized with phenylisothiocyanate (PITC) and separated by reverse phase HPLC, and then taurine is detected by UV at 254 nm. The advantages of this technique for the measurement of taurine are accuracy, small sample size, and reproducibility, and with an automated system many samples can be analyzed.
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The Drash syndrome of Wilms tumor, glomerulonephritis and male pseudohermaphroditism (XY gonadal dysgenesis), was first reported in 1967 [Drash et al, 1970; Denys et al, 1967]. Since then reports have pointed to the delayed appearance of some manifestations of the syndrome with specific attention paid to the late development of renal failure, or Wilms tumor, in patients with XY gonadal dysgenesis. Therefore, early accurate diagnosis of this syndrome is important. We report on a phenotypically and genotypically normal girl with Wilms tumor and glomerulonephritis. This report and others, which indicate that the syndrome may be present in patients without ambiguous genitalia, lead us to suggest that all girls with Wilms tumor should be considered at risk for the Drash syndrome. If possible, a careful evaluation of the ovaries at surgery is advisable. Furthermore, vigilant follow-up of renal function in Wilms tumor patients is warranted.
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