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Biomedical subjects

J E Lewy

Publications and source records attributed to J E Lewy.

At least 19 recordsLinked to original sources
PubMed1992

Urinary tract obstruction and infection in the neonate.

Congenital urinary tract obstruction is a common cause of renal failure accounting for up to 20% of end-stage renal disease cases. Intrauterine obstruction often results in parenchymal loss and renal dysfunction. The pathophysiology of obstructive nephropathy and its further depression of renal function is related to severe renal vasoconstriction, which is in large part angiotensin mediated. Signs suggestive of urinary obstruction in the newborn may include an abdominal mass, hypertension, oligoanuria/polyuria, urosepsis, and hyperchloremic acidosis. The combination of renal ultrasound, diuretic renal scans, and voiding cystourethrogram are the main diagnostic modalities in infants with hydronephrosis. Nonsurgical management of ureteropelvic junction obstruction has become more popular, particularly in mild to moderate cases. Early fulguration or bypassing the obstruction of urethral valves is essential and a decrease in serum creatinine to below 1 mg/dL within 1 month of relief of obstruction is a favorable prognostic sign. Obstruction complicated by infection is dangerous and requires prompt intervention. Any newborn with a urinary tract infection, regardless of sex, should be presumed to have urinary obstruction or reflux until proven otherwise.

Female↗
PubMed1990

Estimation of parenteral fluid requirements.

This article reviews the normal physiologic losses of water and electrolytes from the body, the source of the loss, and the increased body loss of water associated with fever. The three different methods for estimating replacement of water and electrolyte losses are described in this review.

Aging↗
PubMed1987

Reversible vasoconstriction in rats with congenital unilateral hydronephrosis.

We studied the effects of inhibition of either prostaglandins or the role of prostanoids and the renin-angiotensin system on renal function in rats with congenital unilateral hydronephrosis. Wistar rats with congenital unilateral hydronephrosis were infused with normal saline (control), captopril dissolved in normal saline or indomethacin dissolved in a solution of sodium chloride and sodium carbonate. In the control group both glomerular filtration rate (GFR) and effective renal plasma flow were reduced in the right hydronephrotic kidney (RHK) compared with the normal left kidney. Indomethacin did not improve renal function in the RHK. Captopril significantly improved GFR in the RHK. These results support the conclusion that the renin-angiotensin system is an important mediator of reduced GFR in congenital unilateral hydronephrosis in rats.

Animals↗
PubMed1987

Pathogenesis and treatment of edema.

Edema results from excess accumulation of interstitial fluid. This may be due to increased transfer of fluid across the capillary membranes or excess retention of salt and water. The kidneys play a significant role in promoting salt and water homeostasis. Correction of the primary disorder should be the main goal in the management. Diuretics aid in promoting increased excretion of salt and water.

Acute Disease↗
PubMed1985

Erythropoietin response to anaemia in children with sickle cell disease and Fanconi's hypoproliferative anaemia.

The erythropoietin response to anaemia was compared in 30 children with haemolytic anaemia and in 5 children with Fanconi's hypoproliferative anaemia. Serum erythropoietin was measured by radioimmunoassay. In children with haemolytic anaemia the serum erythropoietin concentration increased exponentially with decreasing haematocrit values (r = 0.74; p less than 0.001). Serum erythropoietin levels also correlated with reticulocyte counts (r = 0.62; p less than 0.001). Children with Fanconi's hypoproliferative anaemia had considerably higher serum erythropoietin levels than children with haemolysis for the same degree of anaemia. These data indicate that erythropoietin production in Fanconi's anaemia may be dependent on other factors in addition to the degree of anaemia and relative hypoxaemia.

Adolescent↗
PubMed1985

Erythropoietin and inhibitors of in vitro erythropoiesis in the development of anemia in children with renal disease.

The relative roles of erythropoietin and potential inhibitors of erythropoiesis in the development of anemia in children with renal disease have been studied. Thirty-five children with renal disease of varied origins and severity were compared with 30 children with anemia of similar severity and with normal renal function. Serum erythropoietin was measured by radioimmunoassay; erythroid (CFU-E) and granulocytic (CFU-GM) progenitor cell growth were assessed in fetal mouse liver cell and normal human bone marrow cell cultures, respectively. The degree of serum inhibition of in vitro CFU-E growth in children with renal disease correlated with both creatinine clearance (r = 0.59, P less than 0.001) and hematocrit level (r = 0.55, P less than 0.005). Serum from children with renal disease inhibited in vitro CFU-E growth in a dose-related manner. Normal serum did not inhibit CFU-E growth in culture. The mean serum erythropoietin concentration was significantly (P less than 0.025) higher in children with anemia of renal disease (32.4 +/- 2.4 mU/ml) in comparison with serum values in normal children (19.6 +/- 1.5 mU/ml), but serum erythropoietin levels did not correlate with hematocrit level, creatinine clearance, or serum inhibition of in vitro erythropoiesis. In contrast, children with anemia and normal renal function showed a significant (P less than 0.001) linear increase in serum erythropoietin concentration (range 28.7 to 327 mU/ml), increased reticulocyte count, and stimulation of CFU-E formation with decreasing hematocrit levels. Coincubation of human urinary erythropoietin in the presence of serum from patients with uremia revealed markedly less immunoreactivity in the radioimmunoassay and less biologic activity in the fetal mouse liver CFU-E assay for erythropoietin than when erythropoietin was incubated with normal human serum, suggesting some alteration of erythropoietin in the presence of uremic serum, which reduced both the immunologic and biologic activity of erythropoietin. Normal and uremic sera inhibited CFU-GM growth to the same degree in comparison with controls. In conclusion, relative erythropoietin deficiency, direct alteration in the biologic activity of erythropoietin by uremic toxins, and serum inhibition of erythroid progenitor cells in the bone marrow are probably important factors in the pathogenesis of anemia in children with renal disease.

Acute Kidney Injury↗
PubMed1979

Safety of intravenous diazoxide in children with severe hypertension.

The safety and efficacy of diazoxide administered intravenously in the treatment of children with acute severe hypertension have been evaluated by a collaborative study. Observations of the response of blood pressure in 36 patients, ranging in age from two months to 18 years, during the initial episode of hospitalization reveal diazoxide treatment to be effective in lowering blood pressure in 94 per cent of the cases. No serious adverse circulatory, fluid and electrolyte, metabolic or hematologic effects were observed. Symptomatic and subjective reactions observed with diazoxide administered intravenously to children were identical with those described in adults. Reinstitution of other means of antihypertensive therapy is safe and effective when delayed until the transiently induced period of hypotension has passed. Repeated use of diazoxide for subsequent recurrence of severe hypertension was equally effective and safe in 93 per cent of the instances. The results lead us to recommend the use of intravenous diazoxide for treatment of children with severe symptomatic hypertension especially when it is refractory to control by other hypertensive agents.

Adolescent↗
PubMed1978

Somatomedin and growth retardation in children with chronic renal insufficiency.

The somatomedins are a family of growth hormone-dependent insulin-like peptides which have been postulated to mediate the actions of pituitary growth hormone on skeletal tissue. The somatomedin peptides are part of a larger family of growth factors. Somatomedin has been measured by bioassays, by radioreceptor assays, and recently by a radioimmunoassay. Bioassays are influenced by glucocorticoids, sulfate, heparin, and other inhibitors; radioreceptor assays from different laboratories presently give conflicting results but early experience with the immunoassay is promising. Somatomedin levels are low in hypopituitary states, in malnutrition, and in general when growth hormone is low. Somatomedin's levels in uremia are variously reported. Most bioassays report low values, although the hole of inhibitors is not clear. Values by radioreceptor assays are normal or elevated, but their specificity is unproven. No data are available using radioimmunoassay. No study has addressed end-organ responsivity in uremia.

Biological Assay↗
PubMed1978

Stimulation of p-aminohippurate extraction in the maturing rabbit kidney.

In vivo studies were performed to evaluate maturational changes in PAH extraction (EPAH) in the rabbit and to determine whether accelerated maturation of this process could be achieved. Fifty-four animals were injected with penicillin before study at 10, 14, 21, or 28 days of life. Forty-eight rabbits served as saline-injected controls. PAH extraction in controls increased from 29.3 +/- 2.4% at 10 days of age to 35.9 +/- 3.3% at 14 days, 59.7 +/- 3.5% at 21 days, 71.6 +/- 1.9% at 28 days, and 72.7 +/- 2.3% at 35 days of life. Penicillin injection on the 3 days before study resulted in enhancement of EPAH on days 10 and 14 to 42.7 +/- 2.4% and 65.0 +/- 3.2% (P less than 0.005). On days 21 and 28 less stimulation was noted (68.7 +/- 2.3%; 76.0 +/- 4.1%). Preinjection on days 6--9 with study delayed to day 14 also led to augmentation (46.7 +/- 3.7% P less than 0.05) but less than that achieved after injection on days 10--13. These data suggest that EPAH stimulation may be transient, descreases as maturation is approached and is likely related to substrate availability.

Aminohippuric Acids↗
PubMed1978

Failure to thrive associated with renal disease.

Failure to thrive is a clinical syndrome usually associated with severely reduced increments in height and weight. It is commonly present in patients with chronic renal failure and occurs occasionally in patients with recurrent urinary-tract infections or tubular disorders. Renal osteodystrophy, protein-calorie malnutrition, and chronic glucocorticoid administration have been shown to be important causes of growth failure in patients with renal disease. Altered hormone production, metabolism, or peripheral utilization and acidosis may be causally related to growth failure. Such factors as anemia and hypos-thenuria appear to play no direct role.

Acidosis↗
PubMed1978

The use of furosemide in the treatment of edema in infants and children.

One hundred thirty-seven courses of furosemide therapy were given to 106 hospitalized pediatric patients with salt and water retention associated with cardiac or renal disease. The diuretic was effective and safe in the pediatric age group when administered acutely as a parenteral medication and over a long-term course by the oral route in the doses and at the time intervals used in this study. On the basis of each kilogram of body weight, the infants with edema as a result of cardiac failure and the children with edema secondary to renal disease responded equally well to furosemide therapy.

Administration, Oral↗
PubMed1976

Micropuncture study of fluid transfer in aminonucleoside nephrosis in the rat.

The relationship between glomerular filtration rate and proximal tubular fluid reabsorption was evaluated in control rats and in rats 96 and 144 hr after the injection of an aminonucleoside of puromycin. Urine volume and sodium excretion were decreased in the rats injected with aminonucleoside. Proteinuria increased progressively. Total kidney glomerular filtration rate (GFR) was diminished less than surface nephron GFR at 96 hr and greater than single nephron GFR at 144 hr after injection when a large proportion of nephrons are nonfunctional. Clearance of p-aminohippurate was unchanged initially and depressed subsequently after aminonucleoside injection. Absolute reabsorption to the end of the proximal convolution was unaltered despite a decrease in total kidney filtration fraction. This decrease in GFR coupled with unchanged absolute reabsorption and hence increased fractional proximal reabsorption leads to decreased delivery of sodium and fluid to the more distal portions of the nephron.

Absorption↗