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Biomedical subjects

L G Feld

Publications and source records attributed to L G Feld.

At least 37 records · Page 2Linked to original sources
PubMed1995

Dietary cholesterol supplementation in the spontaneously diabetic rat.

Dietary cholesterol supplementation was used to increase serum cholesterol concentration in diabetic and non-diabetic rats. With the use of numerous dietary formulations, extremely elevated serum cholesterol concentrations and gastrointestinal intolerance were found. We conclude that there are unacceptable side effects with a vast number of exogenous cholesterol supplemented diets which preclude standard and long-term usage.

Animals↗
PubMed1995

Resistance to glomerular injury in the diabetic biobreeding rat.

This study was designed to determine whether the diabetic BioBreeding rat develops significant renal injury following long-term moderate to severe hyperglycaemia. Diabetic and control rats were followed from the onset of diabetes (2-4 months) to 18 months of age. Frank proteinuria and/or albuminuria were always absent. Glomerular filtration rate, measured by inulin clearance (ml min-1 (100 g body weight)-1), was significantly higher in diabetic rats than in controls at 10, 12 and 18 months of age. Advanced glycosylation end-product cross-links assessed by percentage solubility of tail tendon collagen were moderately increased in diabetic compared with control animals. Urinary excretion of advanced glycosylation end-products in unfractionated urine and in urine fractionated for low molecular mass peptides (< 10 kDa) was 11-fold greater in the diabetic rats than in the control group. Urinary excretion of nitric oxide metabolites (nmol NO2- and NO3- (24 h)-1) were significantly (P < 0.05) greater in diabetic rats than in controls after 8 months of age. Mild histopathology resembling human diabetic nephropathy, including increased mesangial volume and glomerular basement membrane thickness, was detected at 18 months of age. The findings of hyperfiltration and mild glomerular morphological changes in diabetic BioBreeding rats are similar to the abnormalities seen in stage 2 human diabetic nephropathy. We hypothesize that two factors which may contribute to the resistance or tolerance to renal injury in the BioBreeding diabetic rat are increased nitric oxide production and the decreased accumulation of advanced glycosylation end-products.

Animals↗
PubMed1995

Microalbuminuria in an adolescent cohort with insulin-dependent diabetes mellitus.

To document the incidence of microalbuminuria in children and adolescents with longstanding insulin-dependent diabetes mellitus (IDDM) and to compare the clinical characteristics and determinant risk factors of those with and without microalbuminuria, 135 adolescent patients with IDDM for 5 years or longer were evaluated. The study population was divided on the basis of microalbumin excretion into normal (< 20 micrograms/min), incipient (20-200 micrograms/min), and overt (> 200 micrograms/min) nephropathy groups. There were 106 patients in the normal group, 24 patients in the incipient group, and five in the overt nephropathy group. Glycosylated hemoglobin, cholesterol concentration, and glomerular filtration rate (GFR) were analyzed. The incidence of incipient and overt nephropathy was 17.8% and 3.7%, respectively. Mean cholesterol concentration in the incipient and overt nephropathy groups (208 +/- 39 mg/dL [5.4 +/- 1.0 mmol/L]) and 227 +/- 49 mg/dL [5.9 +/- 1.3 mmol/L], respectively) was significantly higher than the normal group (186 +/- 37 mg/dL [4.8 +/- 0.9 mmol/L] P < 0.05). Similarly, systolic and diastolic blood pressures were significantly higher in the incipient and overt nephropathy groups compared to the normal group. This study confirms the high incidence of incipient and overt nephropathy in adolescents with IDDM early in the course of the disease.

Adolescent↗
PubMed1995

The relationship between calcium, phosphorus, and sodium intake, race, and blood pressure in children with renal insufficiency: a report of the Growth Failure in Children with Renal Diseases (GFRD) Study.

Nutritional data compiled during the Growth Failure in Children with Renal Diseases Clinical Trial were analyzed to determine the relationship between the dietary intake of divalent minerals and sodium, nutritional status, and serum calcium, phosphorus, and parathyroid hormone (PTH) concentrations and blood pressure in black versus white children. One hundred eighteen patients are included in this report; 25 were black (21%) and 93 were white (79%). Although more of the blacks were male, the age distribution, midarm circumference, midarm muscle circumference, blood pressure, and serum calcium, phosphorus, and PTH concentrations were comparable in the two groups. Phosphorus intake was within the recommended daily allowance in both groups; in contrast, calcium intake was inadequate in all patients: 81% of the recommended daily allowance in whites, and 74% in blacks. Sixteen children were noted to be hypertensive during the observation period; six patients were receiving a variety of antihypertensive medications, including diuretics in two children. Linear regression analysis revealed that systolic and diastolic blood pressures were directly related to calcium and phosphorus intake in black patients. In white children, only dietary phosphorus intake and diastolic blood pressure were directly related. There was no relationship between sodium intake or GFR and blood pressure in the white or black children. PTH levels were directly correlated with systolic and diastolic blood pressure in all children. The correlations between PTH and blood pressure were stronger in white versus black patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Black People↗
PubMed1995

Single nephron hemodynamics in spontaneously hypertensive rats.

This study was designed to determine whether glomerular hypertension develops as a function of age in the spontaneously hypertensive rat (SHR). Male SHR and age-matched Wistar-Kyoto (WKY) normotensive controls were divided into three groups for measurements of whole kidney and single nephron hemodynamics at 5, 10, and 15 months of age. As reported previously, SHR developed significant proteinuria which was predominantly an albuminuria, after 5 months of age. There were no differences in whole kidney or single nephron glomerular filtration rates between SHR and WKY. Afferent glomerular capillary hydraulic pressure (PGC) was slightly increased in SHR compared with WKY at 10 months of age. At 15 months of age, PGC in SHR was significantly lower than WKY. Our studies indicate that increased capillary pressure is not a major factor in the development and progression of renal injury in the spontaneously hypertensive rat.

Age Factors↗
PubMed1994

Applying decision analysis to management of adolescent idiopathic nephrotic syndrome.

Due to the concern that adolescents presenting with nephrotic syndrome are less likely to have minimal change disease than younger children, pediatric nephrologists have tended toward renal biopsy-tailored treatment rather than corticosteroid use in this population. The need for biopsy prior to treatment of nephrotic syndrome in adults has been challenged. A similar challenge to the clinical need for this procedure in adolescents with idiopathic nephrotic syndrome is raised here. The principles of medical decision analysis were applied and calculations were made with the Decision Maker computer program. The life expectancy of an adolescent who receives biopsy-tailored treatment was found to be no different from that of an adolescent who receives empiric corticosteroid treatment. We conclude that renal biopsy is not mandatory for the clinical management of adolescents with idiopathic nephrotic syndrome. Prognostically, a response, or lack thereof, to empiric corticosteroid therapy may be just as informative as a histological diagnosis.

Adolescent↗
PubMed1994

Type III posterior urethral valves: presentation and management.

The clinical and radiographic presentation of infants with type III posterior urethral valves help to distinguish them from patients with the more common type I valves. The diaphragmatic valvular obstruction may make catheterization impossible. Percutaneous cystography can confirm the diagnosis and allow for short-term decompression. The presence of smooth-walled bladders with narrow posterior urethras is unique to type III valves but is not always present. Type III valves present within a spectrum of clinical severity; however, the majority involve significant renal impairment. The prognosis for survival and renal function appears poorer for patients with type III valves than for those with type I valves.

Child, Preschool↗
PubMed1994

Renal function in hypertensive rats transgenic for mouse renin gene.

The recent development of a transgenic rat strain carrying the mouse ren-2 renin gene [TGR(mRen2)27] has provided a new model of hypertension characterized by suppressed plasma renin levels and marked hyperproreninemia. In this long-term study, we examined the kidney function of these animals. Transgenic rats had significantly (P < 0.01) higher blood pressures than control animals at 2, 4, and 8 mo of age. However, the severity of their hypertension diminished over time (225 +/- 8 mmHg at age 2 mo vs. 169 +/- 5 mmHg at age 8 mo, P < 0.001), indicating age-dependent transgene regulation. Whole kidney and single-nephron blood flows and glomerular filtration rates did not differ between control and TGR(mRen2)27 animals studied with micropuncture techniques at 4 and 8 mo of age. Preglomerular vasoconstriction was responsible for this normal autoregulatory response. Elevated preglomerular vascular resistance of transgenic rats prevented transmission of systemic hypertension to glomeruli at 4 but not 8 mo of age leading to increased glomerular capillary pressures in these older animals (53 +/- 1 vs. 48 +/- 1 mmHg, P < 0.05). Pathological albuminuria appeared as early as 2 mo of age but did not increase over the subsequent 6 mo of follow-up. The incidence of glomerulosclerosis, assessed at 4 and 8 mo of age, was greater in TGR(mRen2)27 than control animals (6.6 +/- 1.4% vs. 0.9 +/- 0.3%, P = 0.01) but did not differ between 4- and 8-mo-old transgenic rats. Glomerular ultrafiltration coefficients were significantly elevated (P < 0.05) in transgenic rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Two-day therapy with cefuroxime axetil is effective for urinary tract infections in children.

Short-course therapy for pediatric urinary tract infection (UTI) remains controversial. The present study was undertaken to compare the effectiveness of cefuroxime axetil (Ceftin) as short-course (2-day) versus conventional (10-day) therapy for uncomplicated pediatric UTIs. In a randomized, controlled, prospective study, we enrolled 50 children, 2-11 years of age, to receive oral cefuroxime axetil, 125 mg twice a day, for either 2 or 10 days. UTI was defined as at least 10(5) colonies/ml of a single pathogen isolated on clean catch, or at least 10(4) colonies/ml on a catheterized specimen. A 10-fold or greater reduction in colony count of the initially isolated organism (3-5) days after stopping therapy was considered a bacteriologic success, as long as the absolute colony count was below the threshold for UTI described above. Patients were followed for 15 months with multiple repeat urine cultures and radiologic studies. Twenty-five of the 50 patients enrolled were withdrawn, including 12 for initially inadequate colony counts. Eight of 12 patients in the short-course group (67%), versus 12 of 14 in the conventional-therapy group (86%), were initial bacteriological successes, a nonsignificant difference. All 37 initially isolated uropathogens were sensitive to cefuroxime axetil in vitro. Cefuroxime axetil is an effective antimicrobial for uncomplicated pediatric UTIs. Two-day therapy with cefuroxime axetil appears to be as effective as 10-day therapy, although sample size was limited in this study.

Administration, Oral↗
PubMed1994

Changing pattern of glomerular disease at Beijing Children's Hospital.

Current clinical experience with glomerular disease at a pediatric referral center in Beijing, China, was reviewed. In 1992, renal disorders accounted for 505 of a total 6,885 (7.3%) pediatric medical discharges. Acute glomerulonephritis accounted for 30% of renal diagnoses, while nephrotic syndrome accounted for 28% and Henoch-Schönlein purpura nephritis accounted for 16% of renal disease. Mortality in children with renal disease was 0.4% (two of 505). All children with acute glomerulonephritis recovered or improved at last follow-up, regardless of the relationship to a streptococcal infection. In children with uncomplicated nephrotic syndrome, 91% had a complete or partial response to corticosteroids. Nephritis developed in 81 of 278 patients with Henoch-Schönlein purpura (29%). Since 1956, a dramatic decrease in the diagnosis of acute glomerulonephritis has occurred at this pediatric hospital. Nephrotic syndrome, in contrast, has increased from 45.3 cases per year in the 1956-to-1965 decade to 146 cases annually in the period from 1986 to 1992. Similarly, Henoch-Schönlein purpura has increased from 45.3 cases annually in the 1956-to-1965 period to 238 cases per year in the past 6 years. The incidence of nephritis in patients with Henoch-Schönlein purpura has remained constant at 29% in the past 36 years. These data should be helpful for individuals and institutions who are planning educational or clinical collaborations with pediatric nephrologists in China.

Acute Disease↗
PubMed1994

A proposed method for the noninvasive evaluation of renal asymmetry in a living-related donor candidate.

This report proposes an adjunctive technique for the evaluation of asymmetry of renal size and function of undetermined etiology, discovered during the assessment of two living-related donor candidates. The method utilizes the observation of renal functional reserve measurement as demonstrated by oral protein loading in patients with normal and diseased kidneys. Renal function was measured as timed Ccr and estimation of differential GFR by technetium-99m diethylenetriaminepentaacetic acid (99mTcDTPA) scintigraphy. A comparison of renal function before and after protein loading in two such patients demonstrated the anticipated increase in GFR. No change in differential GFR as determined by renal scan in one patient was interpreted as supportive evidence for bilaterally normal parenchymal function. Follow-up of both donors shows continued normal renal function.

Adolescent↗
PubMed1993

Renal biopsy in children with asymptomatic hematuria or proteinuria: survey of pediatric nephrologists.

The decision to perform a renal biopsy on children with asymptomatic hematuria or proteinuria remains a problem for clinicians. To assess the current opinion of 349 pediatric nephrologists on this issue, case summaries of a 9-year-old boy with 20 urinary red blood cells per high power field without proteinuria and a 9-year-old boy with 2+ proteinuria (600 mg/day) without hematuria were distributed to each specialist. Seventy-three percent (n = 256; 3:1, male:female) responded. Five percent would biopsy the child with asymptomatic hematuria. The main reasons were academic interest, parental pressure for a diagnosis/prognosis and concern for future economic impact on the child (i.e., life insurance). The determinations to biopsy for hematuria were not related to age or sex of the nephrologist. In contrast, 38% (n = 96) of the pediatric nephrologists would perform a biopsy on the child with proteinuria. The major reasons for biopsy were academic interest and potential for drug therapy. With a normal history, physical examination and laboratory/radiographic evaluation, the vast majority of pediatric nephrologists in North America support a conservative approach to the child with asymptomatic hematuria or proteinuria.

Adult↗
PubMed1993

Endogenous creatinine clearance in the rat: strain variation.

The clearance of endogenous creatinine was examined in five strains of rats (Wistar, Wistar Kyoto, Spontaneously Hypertensive Rats, Biobreeding/Worcester diabetic prone and diabetic resistant rats). Creatinine clearance was compared with inulin clearance as the standard. Conditions for clearance measurements were also varied (anesthesia with constant infusion, overnight collection of urine, fed vs. unfed state, single-injection technique). The clearance of creatinine adequately reflects the glomerular filtration rate in three strains (Wistar, Wistar-Kyoto and the Spontaneously Hypertensive Rat). In the two strains of the Biobreeding/Worcester rat creatinine clearance is consistently lower than the inulin clearance. When creatinine clearance is measured from an overnight collection of urine with food withheld it is always lower than when food is present. This clearance should always be validated by comparison with inulin clearance measured simultaneously or under comparable conditions. The ease with which endogenous creatinine clearance can be measured makes it a reasonable method when large numbers of repeated determinations of glomerular filtration rate are required.

Anesthesia↗
PubMed1993

Insurability for asymptomatic hematuria or proteinuria during childhood.

The objective of this survey was to describe life insurance underwriting practices concerning children with asymptomatic hematuria and proteinuria. A questionnaire was sent to 200 companies licensed to issue life insurance policies in the state of New York. The medical director of each company was asked to respond to the insurability of children with asymptomatic hematuria and proteinuria. Two case summaries were provided with the questionnaire. Of 97 companies, 66 would offer insurance to the patient with hematuria, although 38 (58%) would charge additional premiums. In response to the problem of proteinuria, 61 companies would offer life insurance, although 50 (82%) would require higher premium charges (P < 0.002 compared with hematuria). We conclude that children with asymptomatic hematuria and proteinuria can usually obtain life insurance, although often at higher cost. Invasive diagnostic tests are not necessary for insurers to offer insurance.

Child↗
PubMed1993

Serum creatinine, height, and weight do not predict glomerular filtration rate in children with IDDM.

OBJECTIVE: To assess the validity of two equations: K x height/serum creatinine (KL/Cr; K = 0.55 for females 1-18 yr of age and 0.7 for males 12-18 yr of age) and (140 - age) x weight/72 x creatinine (x0.85 for women; Cockroft-Gault) in estimating glomerular filtration rate in children and adolescents with IDDM. RESEARCH DESIGN AND METHODS: From the records of the Children's Hospital Diabetes Clinic, we selected 70 patients with GFR determined by 99mTc-labeled DTPA plasma clearance, stable renal function, and simultaneous measurements of height, weight, blood pressure, HbA1c, and plasma creatinine. We compared DTPA-GFR with estimated GFR from KL/Cr and Cockroft-Gault equations for three groups: all patients, patients with DTPA-GFR < or = 140 ml.min-1 x 1.73 m-2, and patients with DTPA-GFR > 140 ml.min-1 x 1.73 m-2. RESULTS: For all patients, mean values for DTPA-GFR = 147 (95% confidence interval, 139-155), for KL/Cr = 118 (110-125), and for Cockroft-Gault = 84 ml.min-1 x 1.73 m-2 (78-90). For patients with DTPA-GFR < or = 140, DTPA-GFR = 123 (117-128), KL/Cr = 110 (100-119), and Cockroft-Gault = 92 (82-102). For patients with DTPA-GFR > 140, DTPA-GFR = 167 (158-177), KL/Cr = 125 (114-136), and Cockroft-Gault = 77 (71-84). Linear regression analysis showed significant (P < 0.05) relationships for KL/Cr only in patients with DTPA-GFR < or = 140 (r = 0.29), for Cockroft-Gault in all patients (r = -0.46), and for patients with DTPA-GFR < or = 140 (r = -0.31). Determination of a revised K for use in KL/Cr from individual calculations of K (DTPA-GFR x Cr/L) yielded an average value of 0.70 (SD = 0.11). With the use of K = 0.7, the mean KL/Cr value for patients with DTPA-GFR < or = 140 ml.min-1 x 1.73 m-2 was 125 +/- 27 (95% confidence interval, 115-135), compared with a DTPA-GFR value of 123 +/- 14 (95% confidence interval, 117-128). CONCLUSIONS: KL/Cr and Cockroft-Gault do not accurately estimate DTPA plasma clearance. We recommend the use of K equal to 0.70 when estimating GFR in children and adolescents with IDDM and DTPA-GFR < or = 140 using KL/Cr and do not recommend the use of the KL/Cr (for patients with DTPA-GFR > 140) or the Cockroft-Gault equation in this population.

Adolescent↗