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Biomedical subjects

L G Feld

Publications and source records attributed to L G Feld.

At least 19 recordsLinked to original sources
PubMed1992

Serum creatinine level and renal function in children.

OBJECTIVE: To evaluate the accuracy of serum creatinine and height/serum creatinine glomerular filtration rate (Cr-GFR) formula as screening tests for abnormal renal function defined by plasma diethylenetriaminepenta-acetic acid (DTPA) clearance. DESIGN: Patient series. SETTING: The Children's Hospital of Buffalo (NY). PATIENTS: Eighty-seven consecutive patients ranging in age from 2 to 20 years. MEASUREMENTS: The Cr-GFR was calculated by means of the formula GFR (milliliters per minute per 1.73 m2) = kL/serum creatinine (milligrams per deciliter), where L is body length in centimeters and k is a constant dependent on age and sex. Plasma clearance of technetium Tc 99m-labeled DTPA was our reference method for determination of GFR (DTPA-GFR). RESULTS: The Cr-GFR formula identified children with impaired renal function (DTPA clearance, less than 80 mL/min per 1.73 m2) with a sensitivity of 95% and a specificity of 93%. In contrast, the sensitivity and specificity of elevated serum creatinine level for this purpose were 80% and 96%, respectively. Of the children with renal insufficiency (DTPA clearance, 40 to 79 mL/min per 1.73 m2), 91% were correctly identified by the Cr-GFR formula. However, only 65% of these children had elevated serum creatinine levels. Although all children with renal failure (DTPA clearance, less than 40 mL/min per 1.73 m2) had abnormally high serum creatinine levels, the specificity of this test was significantly lower than that of the Cr-GFR formula (75% vs 100%, respectively). CONCLUSIONS: The Cr-GFR formula is superior to serum creatinine level for estimating GFR. This formula provides a simple, reasonably accurate screening test for the presence and severity of impaired renal function.

Adolescent↗
PubMed1992

Association of Kawasaki disease and interstitial nephritis.

Renal insufficiency is a rare manifestation of Kawasaki disease. We report a 2.5-year-old boy with Kawasaki disease who developed acute renal failure during the acute phase of his illness. A percutaneous renal biopsy revealed acute interstitial nephritis. No etiological agent could be identified and renal recovery occurred with supportive care alone.

Acute Kidney Injury↗
PubMed1992

Glomerular function in spontaneously diabetic rats.

This study was undertaken to determine whether hyperfiltration exists at the single nephron level and whether albumin excretion is increased early in the course of diabetes in Biobreeding rats. Diabetic rats were studied at 8-12 weeks after the onset of diabetes. Control animals were age-matched, diabetes-resistant rats. Urinary and tubular fluid albumin concentrations were measured by polyacrylamide gel electrophoresis. Clearance and micropuncture techniques were used to determine whole kidney and single nephron glomerular filtration rate, renal blood flow, and glomerular capillary pressure. The urinary albumin excretion rate (1.3 +/- 0.1 mg/24 hr) and the tubular fluid albumin concentration (4.7 +/- 0.7 mg/dl) in the diabetic group were significantly elevated when compared with urinary albumin excretion (0.9 +/- 0.1 mg/24 hr) and tubular fluid albumin concentration (2.5 +/- 0.5 mg/dl) in the control group. There were no significant differences in glomerular hemodynamics (whole kidney or single nephron glomerular filtration rate or glomerular capillary pressure) between diabetic and control rats. The kidney weight and kidney weight to body weight ratio were significantly higher in diabetic rats when compared with control rats. Early diabetes in Biobreeding rats is characterized by mild albuminuria and increased kidney size, but not glomerular hyperfiltration.

Animals↗
PubMed1991

Progressive glomerular injury after recovery from acute glomerulonephritis in rats.

To determine if an acute immunologic injury resembling poststreptococcal nephritis could lead to chronic renal injury, rats with immune-complex glomerulonephritis produced with cationic human gammaglobulin were followed for 48 weeks. During Week 1, animals developed severe proteinuria, hypoalbuminemia, and a diffuse proliferative/exudative glomerulitis. Substantial recovery, characterized by a significant decline in urinary protein excretion and normalization of plasma albumin concentration, occurred by Week 4. Subsequently, rats developed significantly elevated blood pressures and increasing proteinuria. Glomerular histology at Week 48 revealed minimal inflammation, significant hypertrophy, and considerable sclerosis. We conclude that chronic, progressive renal disease can evolve after apparent recovery from an acute immunologic insult. Further study of this model should provide clinically relevant information about the mechanisms underlying this process.

Acute Disease↗
PubMed1991

Diuretic and natriuretic effects of sorbinil, an aldose reductase inhibitor.

The renal effects of sorbinil, an aldose reductase inhibitor that interferes with the conversion of glucose to sorbitol, were studied in rats and rabbits before and after fluid deprivation. The intracellular osmolar solute, sorbitol, is found in increasing concentrations from cortex to medulla in the kidney and may be involved in the urinary concentrating mechanism. Oral administration of sorbinil in the rabbit resulted in significant increases in urine flow rate and sodium excretion with a tendency toward decreased urine osmolality and increased potassium excretion both before and after water deprivation. When fluid intake was controlled in the rat study, significant increases in urine flow rate and sodium and potassium excretion and a significant decrease in urine osmolality occurred only in response to fluid deprivation. Thus, sorbinil has diuretic and natriuretic properties and may prevent the normal concentration of urine in the antidiuretic animal.

Aldehyde Reductase↗
PubMed1991

Degenerated intramural pericytes ('ghost cells') in the retinal capillaries of diabetic rats.

One of the earliest histopathological signs of diabetic retinopathy is a selective loss of intramural pericytes from retinal capillaries. In the present study, the retinal vessels of rats with streptozotocin-induced diabetes (STZ Wistar) and rats with genetically-induced insulin dependent diabetes mellitus (BB Wistar) and non-insulin dependent diabetes mellitus (SHR/N-corpulent) were examined after 6 to 8 months duration for diabetes-related retinal microangiopathies. The SHR/N-corpulent (cp) rats were fed a 54% sucrose diet, whereas the STZ Wistar and BB Wistar rats were fed laboratory chow for 32 to 36 weeks. In all the diabetic rats, the retinal capillaries in enzyme-digested flat mounts exhibited an increase in periodic-acid-Schiff (PAS) staining and loss of pericytes compared to their respective euglycemic controls. Pericyte "ghosts", like those defined in human diabetes as intramural pockets lacking normal cell contents, were documented by high resolution micrographs in all the diabetic rats. Endothelial cell proliferation, capillary dilation, and varicose loop formation were noted in some of the diabetic rats. Hence, similar capillary lesions were found in very different groups of diabetic rats. The findings suggest that a chronic high tissue concentration of glucose is the underlying factor which triggers pathogenesis in the pericyte. Hyperglycemia-induced activation of endogenous aldose reductase of the polyol pathway is probably the initial insult, but other factors such as advanced glycosylation products may affect the final outcome.

Animals↗
PubMed1991

A simple method for percutaneous renal biopsy.

A technique for percutaneous renal biopsy in children is described which combines the use of ultrasound guidance and a disposable automatic biopsy device. Twenty-five biopsies in 22 children were performed using the Bard Monopty biopsy instrument. Adequate tissue was obtained to aid in diagnosis in 24 of 25 cases. Complications inclused 2 small perinephric hematomas. We conclude that the Bard Monopty biopsy device in association with ultrasonography provides for a safe and reliable technique to perform percutaneous renal biopsy in children.

Biopsy, Needle↗
PubMed1991

Urinary tract infections in childhood: definition, pathogenesis, diagnosis, and management.

Urinary tract infections in childhood are defined as significant bacterial growth in urine obtained by bladder catheterization, suprapubic aspiration, or several clean-voided specimens. In infants and young children they may be easily overlooked because of nonspecific symptoms. This leads to an underestimation of their true prevalence. The severity of these infections is a function of the balance between the various host defense mechanisms and the virulence of the microorganism. The assessment of symptomatic infants and children requires a complete radiographic evaluation (renal ultrasound and voiding cystourethrogram), because of the high frequency of anatomic abnormalities, particularly vesicoureteral reflux. The major issues in the management of children with uncomplicated lower urinary tract infections are whether a single dose or short course of therapy is as efficacious as the conventional 7-10 days, and whether asymptomatic bacteriuria requires treatment.

Anti-Infective Agents, Urinary↗
PubMed1990

Fluid needs in acute renal failure.

Derangements of fluid, electrolyte, and acid-base homeostasis are an inevitable part of acute renal failure. Understanding the pathophysiology of these disorders is essential to treating and preventing potentially life-threatening complications. Appropriate nutritional support is also an important part of management in childhood acute renal failure.

Acid-Base Imbalance↗
PubMed1990

Enalapril and renal injury in spontaneously hypertensive rats.

Rats of the spontaneously hypertensive strain develop kidney damage that resembles the nephropathy seen in some cases of human essential hypertension. Previous studies with a triple drug antihypertensive regimen indicated that proteinuria and glomerular histopathology in spontaneously hypertensive rats might develop despite long-term effective control of systemic blood pressure. To investigate further the relation between hypertension and kidney disease, a group of spontaneously hypertensive rats were treated with enalapril at 15 weeks of age. Blood pressure, protein excretion, and kidney function were measured in those rats at regular intervals during the next year and a half and were compared with untreated spontaneously hypertensive rats and the normotensive Wistar-Kyoto parent strain. Kidney tissue samples from all three groups, collected at autopsy, were stained by immunohistochemical and conventional methods to assess the relative severity and nature of kidney damage. Although enalapril therapy was completely effective in controlling the blood pressure of spontaneously hypertensive rats, it only postponed the onset of kidney disease. Enalapril-treated spontaneously hypertensive rats eventually exhibited albuminuria as severe as that found in hypertensive rats. Kidney vessel pathology was completely prevented with enalapril, but the abnormal accumulation of mononuclear cells in tubulointerstitial and periglomerular sites was the same as in untreated spontaneously hypertensive rats. We have concluded that elevated protein excretion in rats of the spontaneously hypertensive rat strain is not a secondary consequence of systemic hypertension. Structural abnormalities of renal vessels also do not appear to contribute significantly to the pathogenesis of albuminuria in spontaneously hypertensive rats. Other explanations must be sought to account for the close link between spontaneous hypertension and kidney damage in this animal model. The clear dissociation of kidney disease from systemic hypertension exhibited by spontaneously hypertensive rats may also be relevant for human disease.

Albuminuria↗
PubMed1990

Diagnosis and management of the hydronephrotic type of multicystic dysplastic kidney. Use of antegrade pyelography.

The distinction between the hydronephrotic type of multicystic kidney disease and ureteropelvic junction obstruction can be difficult using conventional imaging techniques. Antegrade pyelography with or without percutaneous nephrostomy may be performed to confirm the diagnosis of complete ureteral obstruction and to guide management decisions. One may elect either immediate nephrectomy or observation after performance of this diagnostic procedure. Reconstruction of nonsalvageable kidneys is avoided.

Diagnosis, Differential↗
PubMed1990

Combination of metolazone and furosemide in the treatment of edema in the first month of life.

A combination of metolazone (0.2 mg/kg/day) and furosemide (4 mg/kg/day) was used in the treatment of a 2-week-old neonate who developed severe edema after cardiac surgery. The edema, which was initially responsive to furosemide, became resistant to high doses of this diuretic even with the concomitant use of ethacrynic acid. The addition of metolazone to furosemide induced prompt diuresis and natriuresis. This combination of diuretics can be helpful in the treatment of refractory edema in young infants.

Drug Therapy, Combination↗
PubMed1989

Colonic intussusception secondary to a calcium phosphate bezoar in a child receiving calcium carbonate for hyperphosphatemia.

We report a case of a calcium phosphate bezoar resulting in colonic intussusception in a boy with chronic renal failure who received calcium carbonate to control hyperphosphatemia. Because of concerns about aluminum-related disease in patients receiving aluminum hydroxide phosphate binders, calcium carbonate is being used more frequently to manage phosphate retention in renal failure. The development of bezoars may complicate this new form of therapy.

Bezoars↗
PubMed1989

Dietary protein restriction and renal injury in the spontaneously hypertensive rat.

We examined the influence of a low-protein diet on the course of the renal injury in spontaneously hypertensive rats (SHR) and SHR given antihypertensive drug therapy (SHRD). Antihypertensive drug treatment was hydralazine, reserpine, and chlorothiazide. Wistar-Kyoto (WKY) rats served as normotensive controls. SHR, SHRD, and WKY were each placed on a 24, 14, and 10% protein diet at 5 wk and followed to 80-90 wk of age. Untreated SHR showed a steady rise in protein excretion from 5 to 70 wk regardless of dietary protein content. Protein excretion in SHRD on a 24% protein diet was similar to untreated SHR. However, SHRD on a 14 or 10% diet had a more moderate increase in protein excretion. Glomerular, tubular, and vascular pathology in untreated SHR was not influenced by dietary protein intake. Despite successful antihypertensive therapy, kidney pathology in SHRD on a 24% diet was not significantly different from untreated SHR. In contrast, SHRD on 14 or 10% protein diets had less segmental glomerulosclerosis and vascular pathology than untreated SHR. The results indicate that dietary protein restriction does not influence the course of renal injury in untreated SHR. However, the combination of antihypertensive drug therapy with protein restriction in SHR delays and may arrest progression of glomerulosclerosis and proteinuria.

Animals↗
PubMed1988

Renal reabsorption of phosphate during development: tubular events.

Studies performed in our laboratory on the isolated perfused kidney of the guinea pig have demonstrated that the rate of Pi reabsorption is substantially greater in the newborn than in the adult, when appropriate corrections are being made either for differences in glomerular filtration rate (GFR) or in renal tubular mass. In order to determine the location of this enhanced reabsorption along the nephron, micropuncture experiments were performed on euvolemic, non-fasted guinea pigs 5-14 and 42-49 days of age, maintained on standard guinea-pig chow diet (0.76% Pi). Concomitant measurements of overall kidney function were also obtained. The results confirmed that fractional reabsorption of Pi (TRPi%) across the entire kidney was significantly higher (P less than 0.01) in the newborn (89.93 +/- 2.55%) than in the adult (78.25 +/- 2.89%) animals. The difference was also significant (P less than 0.05) when TRPi was expressed in mol/ml GFR (1.87 +/- 0.14 vs 1.53 +/- 0.12, respectively). At comparable locations along the proximal tubule (TF/Pin of 1.90 +/- 0.16 in the newborn, and 1.79 +/- 0.15 in the adult, P greater than 0.70), the fraction of the filtered load of Pi reabsorbed was significantly higher (P less than 0.001) in the immature (76.66 +/- 2.74%) than in the mature (67.21 +/- 2.74%) guinea pigs. Estimates based on the differences between proximal Pi reabsorption and the urinary excretion of Pi indicate that the reabsorption of Pi in tubular segments located beyond the proximal tubule is also enhanced in the newborn when compared with the adult (15.62 +/- 2.11% vs 10.51 +/- 1.83%, respectively, P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗