Biomedical subjects
L G Feld
Publications and source records attributed to L G Feld.
Analysis of efferent arteriole serum protein by gradient gel electrophoresis.
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Cyclosporine and adult respiratory distress syndrome.
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Age-related changes in serum proteins of the spontaneously hypertensive rat.
Urinary protein excretion and composition in spontaneously hypertensive rats (SHR) change dramatically with age and sex. In this study, serum proteins were analyzed by electrophoresis in male and female SHR and Wistar-Kyoto (WKY) normotensive controls aged 5 to 80 weeks. Serum albumin concentrations of SHR were significantly higher than those of WKY at 5 (4.02 +/- 0.24 vs 3.60 +/- 0.25 g/dl) and 20 weeks (4.30 +/- 0.30 vs 3.77 +/- 0.31 g/dl) and significantly lower at 73-80 weeks (2.73 +/- 0.33 vs 3.45 +/- 0.34 g/dl). In addition, male SHR had significantly lower albumin levels than female SHR after 40 weeks of age. These differences may contribute to the development of hypertension and reflect the appearance of pathologic proteinuria in SHR. In spite of their differences in albumin concentrations, the fractional composition of serum protein from SHR and WKY were undistinguishable. All animals, regardless of strain or sex, manifested a significant decline in the relative amounts of albumin and low molecular weight protein and a significant increase in the relative amount of high molecular weight protein with increasing age. The etiology and significance of these age related changes in the fractional composition of serum protein are unknown, but they differ from the normal developmental pattern in humans.
The approach to fluid and electrolyte therapy in pediatrics.
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Renal effects of atrial natriuretic factor in domestic fowl.
The renal hemodynamic and tubular effects of ANF were investigated using the Sperber technique in chickens. This technique takes advantage of the unique portal circulation of the avian kidney and permits direct access to the renal peritubular space independent of renal arterial blood flow and glomerular filtration. Infusion of ANF into the avian renal portal system increased urine flow rate and sodium excretion by as much as 300% and 100%, respectively. These changes occurred in the absence of significant alterations in glomerular filtration rate or renal plasma flow. There was no significant difference in urine flow, sodium excretion or glomerular filtration rate between the ANF-infused kidney and the contralateral, non-infused kidney. We conclude that the diuretic and natriuretic effects of ANF do not depend on changes in glomerular filtration rate and that the site of action of ANF is the renal medulla.
Hereditary partial deficiency of the third component of complement associated with minimal change nephrotic syndrome.
We describe a 10 year old patient admitted to the Children's Hospital of Buffalo with hypocomplementemia associated with steroid responsive minimal change nephrotic syndrome. The sibling also had a low serum C3 concentration and all family members studied had C3 slow phenotypes. Factor I levels were at the lower limit of normal in the patient and his brother. Functional assays for CH50, total hemolytic C3 and serum concentration of C2, C4-C9 and factors B and H were all within normal limits. This case confirms that a depressed serum complement level can occur in minimal change nephrotic syndrome and indicates that this depression could represent a preexisting inherited rather than an acquired deficiency. The findings are consistent with the presence of a null or hypomorphic C3 slow allele in hypocomplementemic family members. Additional studies are needed to resolve the association between the inherited partial C3 deficiency and minimal change nephrotic syndrome.
Pneumococcal pneumonia and hemolytic uremic syndrome.
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Assessment of renal function in newborn infants.
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Acute renal failure in minimal change nephrotic syndrome.
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Acute renal failure. I. Pathophysiology and diagnosis.
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Acute renal failure. II. Management of suspected and established disease.
Because the pathogenesis of acute renal failure is multifactorial, clinical evaluation and ancillary studies must be performed systematically to reliably differentiate the various disorders. This assessment includes measurement of the serum creatinine and urea concentrations, urine composition and flow rate, and fractional excretion of sodium. Radiodiagnostic techniques such as ultrasound, radionuclide renal scans, and nuclear magnetic resonance may provide useful anatomic and functional information. With this data base, the physician can prescribe an individualized management plan that addresses the fluid, metabolic, and nutritional necessities of the child.
Computed axial tomographic scanning of the thigh: an alternative method of nutritional assessment in pediatrics.
In this study we compared the findings of computed axial tomographic (CT) scanning of the thigh with the findings of arm anthropometry and urinary creatinine determinations to assess nutrition in children with inflammatory bowel disease receiving total parenteral nutrition. All 14 children received our standard solution for total parenteral nutrition as well as prednisone and sulfasalazine (Azulfidine) therapy. All patients were assessed by arm anthropometry, 24-hour urine collections for creatinine clearance, and CT scanning of the thigh during total parenteral nutrition. Arm muscle and fat area were estimated by anthropometry, and those in the thigh were estimated by CT scanning. Our results show the total muscle area from the CT scan can predict muscle mass calculated from the urinary creatinine excretion rates. In addition, there is a close correlation between the thigh muscle area as measured by CT scanning and the muscle area calculated from urinary creatinine excretion rates. In addition, the comparison of thigh muscle area and thigh fat area to the midarm muscle area and midarm fat area, respectively, showed that the thigh is a better predictor of muscle than fat in the midarm. We conclude that the total thigh muscle area is a better predictor of muscle mass as compared to the midarm muscle area. In addition, the CT scan cut at the level of the thigh in children and adolescents with inflammatory bowel disease can provide valuable information about the thigh compartment and analyses of different cross-sectional areas of the thigh.
Hematuria and hypercalciuria following renal transplantation.
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Pseudotumor cerebri associated with cerebral venous sinus thrombosis, internal jugular vein thrombosis, and systemic lupus erythematosus.
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Renal replacement therapy in infants and children.
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A simple estimate of glomerular filtration rate in full-term infants during the first year of life.
An estimate of glomerular filtration rate has been derived for children from body length (L, in centimeters) and plasma creatinine (Pcr, in milligrams per deciliter): GFR = 0.55 L/Pcr. The near universality of this estimate in children led us to seek a similar formula for estimating GFR in full-term infants during the first year of life. We measured Pcr in 137 healthy infants and performed creatinine clearance (Ccr) studies in 63 of them aged greater than or equal to 5 days. Beyond the first week, Pcr averaged 0.39 +/- 0.01 (0.10 SD) mg/dl. The estimate of GFR from 0.55 L/Pcr overestimated Ccr by 24% (P less than 0.001). Based on the calculation of a new constant from Ccr X Pcr/L, GFR was more accurately estimated from 0.45 L/Pcr (mean difference of Ccr - 0.45 L/Pcr = -0.4 +/- 3.7 (SE) ml/min X 1.73 m2) in full-term infants between 1 and 52 weeks of age. Because the constant 0.45 and Pcr do not change significantly during this period, GFR can be approximated at the bedside from body length of the healthy full-term infant (GFR = 0.45 L/0.39 = 1.1 L).
The effect of neonatal hyperbilirubinemia on the measurement of plasma creatinine.
Bilirubin interferes with the measurement of plasma creatinine by the kinetic colorimetric Jaffe reaction, the method currently used by many hospital laboratories. The purpose of the present study was to evaluate the influence of unconjugated bilirubin on the measurement of plasma creatinine by the AutoAnalyzer Jaffe end point method. This colorimetric method is slower but more precise and accurate in the range of 0.25 to 0.5 mg/dl. We found that bilirubin from jaundiced neonates and from stock solutions did not affect the determination of creatinine chromogen in plasma or in saline, even at concentrations as high as 25 mg/dl. We conclude that the use of the Jaffe end point AutoAnalyzer method with a blank run before each sample will provide an accurate measurement of creatinine in the plasma of the neonate with unconjugated hyperbilirubinemia.