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Biomedical subjects

B A Warady

Publications and source records attributed to B A Warady.

At least 19 recordsLinked to original sources
PubMed1992

Creatinine for estimation of glomerular filtration rate.

The aim of this study was to evaluate the plasma creatinine concentration (PCr) and creatinine clearance (CCr) for estimation of glomerular filtration rate (GFR). Inulin clearance (Cin) was used as the reference standard for GFR. Thirty-nine concurrent Cin and CCr studies provided data for comparing Cin with the measured CCr and with the calculated CCr (calc-CCr). (Calc-CCr = k.L/PCr, where L = height in centimeters and k is the proportionality constant.) Thirty-one children 5.3-20.8 years of age, with Cin ranging from 2.8 to 138.8 ml/min per 1.73 m2, participated in these studies at The Children's Mercy Hospital. The measured CCr was 16.7 +/- 10.3 ml/min per 1.73 m2 (P < 0.001) greater than the Cin, and the calc-CCr overestimated Cin by a mean of 31.6 +/- 20.8 ml/min per 1.73 m2 (P < 0.001). Although there is good correlation between Cin and CCr (r = 0.96), and Cin and calc-CCr (r = 0.90), the 95% confidence intervals are quite broad. Hence, the CCr and the calc-CCr, derived using Schwartz values for k, consistently overestimate GFR. However, if the k value in the equation GFR = k.L/PCr is derived from k = Cin/L, rather than from k = CCr.PCr/L, a more accurate estimate of GFR may be obtained.

Adolescent↗
PubMed1992

Hyperkalemia in very low birth weight infants.

PURPOSE: To assess the frequency and pathogenesis of hyperkalemia in the very low birth weight infant. METHODS: Infants who weighed less than 1000 gm at birth were prospectively entered into the study within 12 hours of birth. Potential risk factors for hyperkalemia were assessed. Body weight, fluid and electrolyte balance, serum levels of sodium and potassium, creatinine clearance, fractional sodium excretion, and urine sodium/potassium ratio were measured every 8 hours for 72 hours. Measurements of plasma renin, serum aldosterone, and plasma atrial natriuretic factor were made at study entry and repeated when hyperkalemia (serum potassium greater than 6.5 mmol/L) occurred or at 72 hours. Infants in whom hyperkalemia developed were compared with those in whom it did not. RESULTS: Thirty-one infants completed the study; hyperkalemia developed in 16 (51.6%). The only difference in the occurrence of perinatal complications was the more frequent occurrence of pH less than 7.20 in infants with subsequent development of hyperkalemia. Creatinine clearance, urine output, and potassium excretion were significantly lower in the hyperkalemia group during the first 24 hours. Serum potassium concentration at 24 hours was inversely related to urine output in the prior 24 hours. Fractional sodium excretion, urine sodium/potassium ratio, and levels of renin, aldosterone, and atrial natriuretic factor did not differ between groups. CONCLUSIONS: Hyperkalemia is a frequent complication in very low birth weight infants. Infants with low urinary flow rates during the first few hours after birth are at greatest risk for the development of hyperkalemia.

Aldosterone↗
PubMed1992

Metabolic and histologic investigation of the nature of nephrocalcinosis in children with hypophosphatemic rickets and in the Hyp mouse.

To investigate the biochemical nature of nephrocalcinosis in children with hypophosphatemic rickets treated with orally administered phosphate and vitamin D, we studied five such patients, aged 3.7 to 12.3 years, during treatment and again 3 days after it had been discontinued. Treatment was associated with significant increases in mean serum phosphate concentration and urine phosphate/creatinine ratio, from 0.71 to 1.03 mmol/L and from 3.61 to 9.42 mmol/mmol, respectively. Significant correlation was found between urine phosphate/creatinine and oxalate/creatinine ratios (r = 0.670; p less than 0.01); however, the mean urine oxalate/creatinine ratio of 65.0 mumol/mmol while patients were taking phosphate orally was not significantly different from the ratio of 59.0 mumol/mmol when treatment was discontinued. Kidney biopsy specimens from three of the patients showed that the renal calcifications were located mainly intratubularly and were composed exclusively of calcium phosphate. In a further investigation of the nature of phosphate-induced nephrocalcinosis, six 6-week-old male Hyp mice, the murine analog of the human disease, received oral phosphate therapy with drinking water for 48 days; six others served as control animals. Mice in the experimental group excreted more phosphate (p less than 0.001) and less calcium (p less than 0.01) than control mice did, and medullary nephrocalcinosis, with a high kidney calcium content, developed (p less than 0.001). Histologic sections showed that the renal calcifications were located intratubularly and were composed of calcium phosphate. We conclude that, both in children with hypophosphatemic rickets and in the Hyp mouse, the development of nephrocalcinosis is associated with high oral phosphate intake and subsequent deposition of calcium phosphate precipitates in the kidney.

Animals↗
PubMed1992

Residential summer camp for children with end-stage renal disease.

Residential summer camps exist for children with all varieties of chronic illness with the goal of improving their quality of life. This paper describes the development and implementation of a summer camp for children 9-18 years old who receive long-term peritoneal dialysis or who have received a kidney transplant. Thirty-five to forty children regularly participate in activities such as water olympics, survival hikes and campouts while continuing to receive their medical needs from trained personnel. A study to evaluate the impact of a summer camp revealed less patient hopelessness and improved self-esteem following the 1-week camping experience. Attendance at camp provided the medical staff with a unique perspective of childhood illness, while the period of respite for the parents was uniformly welcomed and may contribute to the prevention of parent burnout. It is hoped that the success of this camp and others like it will lead to the development of similar experiences for other children with chronic disease.

Adolescent↗
PubMed1991

Recombinant human erythropoietin therapy in pediatric patients receiving long-term peritoneal dialysis.

We evaluated the impact of (s.c.) recombinant human erythropoietin (r-HuEPO) therapy on the hematological status, exercise capacity, and dietary intake of nine pediatric patients (mean age 12.4 +/- 3.2 years) receiving long-term peritoneal dialysis. Five children without medical illness served as controls for the exercise testing portion of the study. Following 7.9 +/- 2.8 weeks of twice weekly r-HuEPO (50 units/kg per dose), the hematocrit increased from 21.9 +/- 3.5% to 31.3 +/- 2.5% (P less than 0.001). A further increase to 33.2 +/- 3.0% occurred after 2 months of once weekly therapy. The blood transfusion requirement decreased from 0.5 transfusions per patient-month to 0.05 transfusions per patient-month (P less than 0.01). Graded exercise testing demonstrated an increase in peak oxygen consumption from 17.8 +/- 5.2 to 24.0 +/- 7.6 ml/kg per min (P less than 0.01). The oxygen consumption at anaerobic threshold increased from 13.1 +/- 3.9 to 17.1 +/- 3.5 ml/kg per min (P less than 0.02). Treadmill time increased from 5.3 +/- 1.2 to 7.5 +/- 1.3 min (P less than 0.001). In each case, the percentage improvement was significantly greater than the improvement seen in the control population. Dietary evaluation revealed no significant change in caloric or protein intake, despite a subjectively improved appetite. r-HuEPO, given by the s.c. route, corrects the anemia and improves the exercise capacity of pediatric patients receiving long-term peritoneal dialysis.

Adolescent↗
PubMed1991

Oral acetazolamide in the assessment of (urine-blood) PCO2.

Urine-blood (U-B)Pco2 difference in children is usually assessed following urine alkalinization with oral sodium bicarbonate (NaHCO3). Since oral NaHCO3 is often poorly tolerated by children, we compared oral acetazolamide with oral NaHCO3 in a study of (U-B)Pco2. In the first phase of the study 14 children and adolescents aged 11.1 +/- 3.7 years (mean +/- SD) were studied. Eight participants had normal kidney function and 6 had disturbed distal acidification capacity. Each child was studied twice, once with oral NaHCO3 (2.5 mEq/kg) and once with acetazolamide (17 +/- 2 mg/kg). All studies were performed according to the standard protocol. Acetazolamide administration resulted in a lower blood pH than NaHCO3 (7.30 +/- 0.03 vs 7.38 +/- 0.06, P less than 0.001) and a lower serum bicarbonate (HCO3-) concentration (25.1 +/- 2.2 mEq/l vs 27.5 +/- 2.1 mEq/l, P less than 0.025). Acetazolamide also resulted in a higher urine Pco2 (81.9 +/- 26.2 mm Hg vs 71.6 +/- 18.2 mm Hg) than NaHCO3 (P less than 0.025). No significant differences between acetazolamide and NaHCO3 were observed with respect to their effects on urinary pH and HCO3- concentration, plasma Pco2 and (U-B)Pco2. Good linear correlations were found between the effects of acetazolamide and NaHCO3 on urine Pco2 (r = 0.878, P less than 0.001), and on (U-B)Pco2 (r = 0.795, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetazolamide↗
PubMed1991

Vitamin status of pediatric patients receiving long-term peritoneal dialysis.

The oral vitamin intakes and concentrations of vitamins in blood of eight children on long-term peritoneal dialysis and six control children were measured. All patients received a daily supplement containing water-soluble vitamins. Serum concentrations of vitamin A, vitamin B-12, ascorbic acid, and folic acid and dialysate concentrations of ascorbic acid were determined. Thiamin and riboflavin were assessed by measuring erythrocyte enzyme activities. Vitamin B-6 was measured as plasma pyridoxal phosphate. Dietary vitamin intake was determined with weighed 3-d food records. The dialysis patients had significantly greater stores of vitamin A, thiamin, riboflavin, pyridoxal phosphate, and folic acid than did the control population (P less than or equal to 0.01). The patients' combined dietary and supplemental intake of all vitamins except ascorbic acid was also significantly greater than the intake of the control group (P less than 0.01). Vitamin supplementation is associated with normal or greater-than-normal values of water-soluble vitamins in pediatric patients receiving long-term peritoneal dialysis.

Child↗
PubMed1991

Primary nocturnal enuresis: current concepts about an old problem.

In summary, all children and families who present with nocturnal enuresis should be offered education, reassurance, and ongoing support as a premier component of any treatment regimen. At the same time, the family should be informed about all the treatment options that exist with a goal of tailoring the specific treatment to the individual patient. In most cases, this approach will lead to child, family, and physician satisfaction.

Behavior Therapy↗
PubMed1990

Linear growth and anthropometric and nutritional measurements in children with mild to moderate renal insufficiency: a report of the Growth Failure in Children with Renal Diseases Study.

During the control period of the Growth Failure in Children With Renal Diseases Study, investigators at 23 centers were able to observe and characterize growth and to make anthropometric and nutritional measurements in 82 children with mild to moderate renal insufficiency. As a multicenter, controlled clinical trial designed to study the relative efficacy of 1,25-dihydroxyvitamin D3 and dihydrotachysterol in the treatment of renal osteodystrophy, no prior vitamin D exposure and a creatinine clearance of 25 to 75 ml/min/1.73 m2 were criteria for entrance into the clinical trial. Ages ranged from 18 months to 11 years (mean 5.6 +/- 3.1 years), and distribution by age category was as follows: 38%, 1 to 3 years; 28%, 4 to 6 years; and 34%, 7 to 10 years. There was a 3:1 male/female ratio; 72% of the patients had congenital disease by the International Classification of Diseases (ninth revision). Mean creatinine clearance was 49.5 +/- 20 ml/min/1.73 m2. The C-terminal parathyroid hormone values (1121 +/- 1562 pg/ml) were well above 2 SD of the mean of a normal growing population of similar age. Parathyroid hormone values correlated with degree of renal insufficiency (r = -0.57) and with height by bone age but not with chronologic height or growth velocity. The bone age/height age ratio, a predictor of growth potential in normal children, was low for the entire series of patients (0.88 +/- 0.35) but failed to correlate with growth velocity and was negatively correlated with rising parathyroid hormone levels. Average values for height, weight, triceps skin fold, mid-arm muscle circumference, and body mass index were within 2 SD of the mean of the normal population, although measurements for the 1- to 3-year age group were significantly less than those of the older patients. Total energy intake averaged less than 86% of the recommended dietary allowances; total protein intake was more than 161% of the allowance. Nitrogen balance in 23 patients was positive and correlated most significantly with increasing energy intake (r = 0.6). Growth velocity, calculated from the interval gain during the month control period, averaged +0.3 SD, with the highest growth velocity z scores recorded for those with acquired disease. A growth velocity index, expressed as the slope of the regression between change in height SD and growth velocity z score, was used to describe the growth accomplished in the control period by age category.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Determination by Skeleton↗