Sodium transport and bone mineral density in hypercalciuria with thiazide treatment.

Erythrocyte sodium-potassium (Na+/K+)-ATPase and sodium-lithium (Na+/Li+) countertransport activities were measured in 18 children (aged 9.6 years, range 6-16 years) with idiopathic hypercalciuria (IHU) to evaluate cellular Na handling. The effect of chronic thiazide administration on these parameters and on bone mineral density was also evaluated. Patients with IHU had significantly lower erythrocyte Na+/K+-ATPase activity than 23 age-matched healthy controls (mean +/- SEM 2,156 +/- 110 micromol P/l erythrocyte per hour vs. 3,165 +/- 175, P < 0.01). Thiazide treatment significantly lowered urinary calcium excretion; this was followed by a slight suppression of intact parathyroid hormone (iPTH). The urinary calcium/creatinine ratio before and during treatment was 0.90 +/- 0.07 mmol/mmol versus 0.51 +/- 0.06 respectively, P < 0.01. The corresponding iPTH levels were 5.9 +/- 0.6 pmol/l and 5.1 +/- 0.7, P < 0.05. The Na+/K+-ATPase activity increased significantly (2,769 +/- 169 micromol P/l erythrocyte per hour vs. 2,156 +/- 110 in the control period, P < 0.01) and the Na+/Li+ countertransport decreased (268 +/- 28 micromol Li/l erythrocyte per hour vs. 328+26 in the control period, P < 0.03). The bone mineral density Z score rose from -1.3 +/- 0.26 to -0.8 +/- 0.22 (P < 0.03). We conclude that IHU is accompanied by abnormalities of erythrocyte Na+/K+-ATPase and Na+/Li+ countertransport which are corrected by chronic hydrochlorothiazide administration. These changes could model alterations in renal tubular transport mechanisms still to be elucidated. Chronic thiazide treatment also has a positive effect on bone mineral density.

X-linked hypophosphatemia: effects of treatment with recombinant human growth hormone.

The impact of recombinant human growth hormone (rhGH) treatment on growth, bone mineral metabolism, and bone mineral density (BMD) was evaluated in six children (3 girls, 3 boys) with familial hypophosphatemic rickets (XLH). Five were prepubertal (aged 6-8.8 years), one 15.3-year-old boy had combined XLH and GH deficiency, but had not been treated with rhGH previously. rhGH was administered daily for 1 year, at a dose of 1 IU/kg per week, combined with 1,25-dihydroxyvitamin D3 and oral phosphate therapy. Z scores for growth velocity and height improved significantly (-2.9 vs. 2.5, P < 0.01, and -2.2 vs. -1.5, P < 0.01, respectively). However, the ratio of Z score for height to that of subischial leg length decreased significantly (0.65 vs. 0.43, P < 0.01), indicating disproportionate growth in favor of the trunk. The height-corrected BMD Z increased slightly (-0.99 vs. -0.94, P < 0.05). A slight increase in serum phosphate occurred (0.78 vs. 0.88 mmol/l, P < 0.02). Tubular reabsorption of phosphate/glomerular filtration rate increased from 0.45 mmol/l to 0.55 mmol at 6 months (P < 0.02), but returned to the initial level at 12 months. These results indicate that children with XLH can benefit from the positive effect of rhGH on growth, however treatment could aggravate the already existing tendency to disproportionate growth. GH production should be evaluated in poorly growing patients with XLH, because it can mask GH deficiency. rhGH can be safely combined with conventional treatment in XLH. Further studies are needed to determine the effect of treatment on final height and maximal BMD.

Efficiency and toxicity of ifosfamide, cisplatin and doxorubicin in the treatment of childhood hepatoblastoma. Study Committee of the Cooperative Paediatric Liver Tumour Study HB89 of the German Society for Paediatric Oncology and Haematology.

The Cooperative German Paediatric Liver Tumour Study HB89 was conceived to evaluate the efficiency and toxicity of ifosfamide, cisplatin and doxorubicin (IPA) in children with resectable and non-resectable hepatoblastoma (HB) and to determine late sequelae including tubular nephropathy of tumour treatment. The study also assessed the results of a surgical strategy, which adapts the procedure at the initial operation to the tumour's extension in the liver. The relationship of the tumours' histological differentiation to response to chemotherapy was also examined. Patients with a HB restricted to one liver lobe underwent primary resection. Larger tumours were initially treated with IPA chemotherapy and resected at second-look surgery. All patients received IPA adjuvantly after tumour resection. The IPA regimen consisted of ifosfamide 3.5 g/m2 (over 72 h days 1-3), cisplatin 100 mg/m2 (over 5 days 4-8) and doxorubicin 60 mg/m2 (over 48 h, days 9-10). Median follow-up of survivors was 64 months (range 28-82). Long-term disease-free survival (DFS) was for stage I: 21/21; stage II: 3/6; stage III: 28/38; and stage IV: 2/7 (overall 75%). Severe surgical complications occurred in 15% (4/27) of primary and 21% (8/38) of secondary resections with no lethality. 44/45 stage III/IV HB displayed PR after two IPA courses. Drug resistance developed in 8/12 tumours after four or five chemotherapy courses. Acute toxicity was observed in 34/242 (14%) IPA courses. Late sequelae were found in 7/54 (13%) of survivors, and subclinical renal tubulopathy occurred in 7/41 investigated patients (17%). Despite a more favourable prognosis in pure fetal and predominantly fetal histology, statistical analysis revealed no relationship between tumour differentiation and response to chemotherapy. In conclusion, IPA chemotherapy in combination with delayed surgery was highly effective in the treatment of HB.

Oxalate elimination via hemodialysis or peritoneal dialysis in children with chronic renal failure.

Oxalate elimination and oxalate dialysance via hemodialysis (HD) or peritoneal dialysis (CAPD) has not been studied in detail in pediatric patients. We studied plasma oxalate, oxalate elimination, and oxalate dialysance in 15 infants and children undergoing CAPD (9 female, 6 male, aged 9 months to 18 years) and in 10 children on HD (4 female, 6 male, aged 7-18 years). Two children in each group had primary hyperoxaluria (PH). The mean duration of dialysis prior to examination was 12 +/- 11 months in CAPD and 31 +/- 23 months in HD patients. Bicarbonate HD was performed 5 h three times a week, CAPD consisted of five daily exchanges in 5 patients and four changes in the remaining 10 children (dwell volume 40 ml/kg body weight, 2.3 g/l glucose). Although oxalate dialysance was significantly higher in HD (mean 115.6 ml/ min per 1.73 m2 in HD versus 7.14 ml/min in CAPD), mean oxalate elimination per week was not different between both renal replacement therapies (3,478 mumol/1.73 m2 surface area/week in CAPD versus 3,915 mumol/1.73 m2 per week in HD). Oxalate elimination in patients with PH was between 6,650 and 9,900 mumol/week. Plasma oxalate remained elevated in both procedures [28-84 mumol/l in CAPD (92/148 in PH) and 33-101 mumol/l in HD (70/93 in PH)]. Oxalate elimination can be increased by a more frequent hemodialysis regimen.

[Normal values of calcium and oxalate excretion in children]. / A kalcium- és oxalátürítés normálértékei gyermekekben.

Aim of the study was to establish normal values for calcium/creatinine (Ca/cr) and oxalate/creatinine (Ox/cr) ratio in infants and children. Urine probes of 416 healthy children (25 infants aged 1-7 days and 391 children aged 1 month-14.5 years) were analysed. Oxalate was measured by ion-chromatography. Urinary Ca2+/cr was normally distributed, Ox/cr had log-normal distribution. Ca/cr was the lowest in the first days of life, the highest between 7 month-1.5 years (mean +/- SD = 0.39 +/- 0.28 mmol/mmol), a slight decrease could be observed until 14 years (0.34 +/- 0.18). The highest Ox/cr values were measured during the first month of life (geometric mean/range/ = 133 /61-280 mmol/mmol/), followed by gradual decrease until 14 years (25/6-73/). The measurement of Ca2+/cr and Ox/cr in first morning urine samples is suitable for screening of hypercalciuria and hyperoxaluria. The interpretation of the values requires age specific reference values. Both calcium and oxalate determinations should be the part of the evaluation of patients with hematuria, hypercalciuria or nephrolithiasis.

Regulation of the mitochondrial ATP-synthase in human fibroblasts.

The F1F0-ATPase activity of mitochondrial complex V can be rapidly measured in sonicated preparations of monolayer skin fibroblast cultures from children. We show that direct regulation at the level of ATP-synthase occurs in these cell preparations. ATP-synthase capacity is decreased in response to blocking of the respiratory chain by cyanide (mimicking anoxia) or uncoupling of mitochondria. ATP-synthase capacity falls to 60% and 35% of control, respectively. Up-regulation of ATP-synthase can be demonstrated in fibroblasts exposed to 4 mmol/l calcium (127% of control). Mitochondrial recovery was unchanged under the different incubation conditions as judged by the activity of mitochondrial marker enzymes. We conclude that direct regulation at the level of ATP-synthase occurs in vivo in human fibroblasts. The naturally occurring inhibitor protein IF1 and the calcium binding inhibitor protein CaBI may be involved in this regulation of ATP-synthase.

Absence of cytochrome c oxidase activity in a boy with dysfunction of renal tubules, brain and muscle.

We report on a boy who developed proximal renal tubular acidosis with loss of carnitine at the age of about 6 months. A few months later he began to suffer from progressive muscular weakness and neurological disturbances. Blood biochemistry showed elevated lactate and beta-hydroxybutyrate with increased lactate/pyruvate and beta-hydroxybutyrate/acetoacetate ratios. A high urinary excretion of lactate and citric acid cycle intermediates was found. These results indicated a defect of the mitochondrial respiratory chain. Analysis of biopsy material from skeletal muscle revealed low activities of all respiratory chain complexes. In muscle and fibroblasts cytochrome c-oxidase (complex IV) was absent. Despite high dose multi-vitamin therapy the boy died at the age of 30 months from central respiratory failure. At autopsy the neuropathological diagnosis of Leigh disease was made.

Determination of oxalate excretion in spot urines of healthy children by ion chromatography.

Evidence for the suitability of spot urines for selective screening in children was obtained by comparing the 24-hour urinary oxalate excretion with the ratio of urinary oxalate to creatinine [mmol/mol] in spontaneously voided urine samples. Spot urines of 169 healthy children aged 1 day to 13 years were analysed in order to establish reference values for the urinary oxalate/creatinine ratio in relation to age and body surface area. Oxalate was measured by automated ion chromatography. Results showed an inverse relationship between the oxalate/creatinine ratio and age. The highest ratios, 131 +/- 57 mmol/mol (mean +/- 2 SD), were found in infants. At age two years, the ratio was 84 +/- 55, at age five years 56 +/- 35, and for children older than ten years 42 +/- 31. This finding can be explained by the gain of muscle mass and hence increased creatinine production with increasing age. Data for the urinary oxalate/creatinine ratio are presented according to body surface area for the assessment of children with abnormal growth. In 19 urine samples from nine patients with primary hyperoxaluria, the oxalate/creatinine ratio greatly exceeded (286-2022 mmol/mol) the above reference ranges. We therefore propose the determination of the oxalate/creatinine ratio in spot urines for the selective screening for hyperoxaluria in children with nephrocalcinosis or urolithiasis.

The plasma amino acid profile and its relationships to standard quantities of liver function in infants and children with extrahepatic biliary atresia and preterminal liver cirrhosis.

The absolute and relative concentrations of 16 plasma amino acids in 48 mostly dystrophic infants and children (median of age 1 1/2 years) with extrahepatic biliary atresia and mainly stable preterminal cirrhosis were compared with those of controls. Patient plasma amino acid data were analysed statistically for diagnostic usefulness and correlated with standard biochemical quantities of liver function and of liver perfusion. In the patients the total amounts of non-essential and essential amino acids were reduced by 19% and with the same significance (p < 0.0005). Plasma tyrosine was increased (+40%), while taurine (-44%) and branched chain amino acids (+28.8% to -34.7%) were decreased. Methionine values varied widely. In the molar fractional plasma amino acid profile, only alanine, valine, and leucine were decreased, while threonine, methionine, tyrosine, phenylalanine, ornithine, and serine were increased. Discriminate function analysis showed that the plasma amino acid data discriminated 93.8% of the patients from controls. The concentrations of some amino acids in plasma seemed to have been influenced by protein-calorie deficiency in the patients. The valine/tyrosine ratio and the Fischer index (ratio branched chain/aromatic amino acids) were significantly reduced in the patients versus controls (1.54 +/- 0.55 vs 3.08 +/- 0.55 and 1.66 +/- 0.39 vs 3.00 +/- 0.48). A number of significant correlations (range of r: 0.37-0.59, p < 0.05, 30-48 data pairs) were calculated between plasma amino acid data and several standard biochemical quantities of liver function. The statistical analyses also showed that the Fischer index began to decrease gradually and linearly early in the progression of liver failure.(ABSTRACT TRUNCATED AT 250 WORDS)

[Biotinidase deficiency. Results of neonatal screening 1985-1989 in Lower Saxony]. / Der Biotinidasemangel. Ergebnisse des Neugeborenen-Screenings 1985-1989 in Niedersachsen.

During a five-year-period (1985-1989) 420,000 newborns in Lower Saxony, FRG, were screened for biotinidase deficiency using biotinyl-para-amino-benzoic-acid as substrate. Three newborns with profound biotinidase deficiency (activity 1.1%, 2.1%, 2.3% of mean normal activity level) were detected. Nine newborns had partial biotinidase deficiency (activity 17-26% of mean normal activity level), thus giving an incidence of 1:140,000 with profound, and 1:46,667 with partial biotinidase deficiency, respectively. The infants with profound biotinidase deficiency are treated with biotin (2 x 5 mg/day) from the 3rd, 6th and 8th week of life and have developed normally so far. The children with partial biotinidase deficiency are not treated but followed up closely. The necessity of newborn screening for biotinidase deficiency is stressed.

Diagnostic and genetic studies in 43 patients with classic cystinuria.

We present results for laboratory screening and diagnostic tests--cyanide-nitroprusside test, semi-quantitative thin-layer chromatography, and quantitative amino acid column chromatography--of 43 patients with classic cystinuria. We report the efficaciousness of the cyanide-nitroprusside test and of thin-layer chromatography, as compared with quantitative amino acid chromatography, for detecting heterozygotes for type II or III cystinuria. The quantitative results for aminoaciduria in 57 blood relatives in 23 families were used to categorize the index patients with classic cystinuria. By column chromatography the ranges of excretion rates (mumol/24 h per 1.73 m2 body surface area) of diagnostic amino acids in the index patients were as follows: cystine 556-54044 (normal 20-128), arginine 131-11543 (10-80), lysine 768-21848 (51-514), ornithine 185-5685 (0-80). Also by column chromatography the median values for arginine and ornithine excretion in cystine-lysinuric heterozygotes (among the 57 blood relatives) were significantly higher (P less than 0.01) than in controls but never approached the values for homozygotes. The cyanide-nitroprusside test results were positive in urine samples of 41 of 43 index patients and in 16 (51.6%) of the urine samples of 31 obligate heterozygotes with column chromatographically proven cystine-lysinuria. Thin-layer chromatography detected all of the homozygotes, all the compound heterozygotes, and 54.8% of the carriers. According to the type of aminoaciduria in their relatives, 11 patients with classic cystinuria could be classified as having classic cystinuria type I, 11 as having type II or III, and three as being compound heterozygotes. We discuss the implications of these results for correct diagnoses and for genetic studies in classic cystinuria.

Evidence suggesting hyperoxaluria as a cause of nephrocalcinosis in phosphate-treated hypophosphataemic rickets.

Urinary excretion of oxalate and phosphate was measured in twelve vitamin-D-treated, phosphate-supplemented patients with X-linked hypophosphataemia (XLH; four children, eight adolescents and adults) to investigate possible causative factors of nephrocalcinosis other than calcium. Oxalate excretion correlated highly with urinary phosphate excretion and with intake of phosphate supplements corrected for body surface area. Young children received the highest relative doses of phosphate (range 2.27-10.8 g/1.73 m2 daily) and their urinary oxalate excretion was very high (0.94-3.38 mmol/1.73 m2 daily). The urinary oxalate excretion of untreated adults with XLH was within normal limits. Six patients had evidence of nephrocalcinosis on ultrasound. The high urinary oxalate excretion in phosphate-supplemented XLH may be seen as a special type of enteric hyperoxaluria, in which the conditions of calcium-oxalate crystal precipitation could be reached even at normal levels of urinary calcium excretion. Urinary excretion of both calcium and oxalate should therefore be monitored during treatment in young XLH patients.

Neonatal pyruvate dehydrogenase deficiency with lipoate responsive lactic acidaemia and hyperammonaemia.

A 2-day-old girl developed a severe lactic acidosis with a normal lactate/pyruvate ratio and hyperammonaemia. Plasma arginine and citrulline levels were below the limit of detection. In muscle total pyruvate dehydrogenase complex (PDHC) and pyruvate decarboxylase (E1) activities were reduced to a fraction of lower control values. The acute neonatal period was bridged with peritoneal dialysis, dichloroacetate therapy, supplements of arginine and branched chain amino acids, a complete vitamin B complex and lipoic acid. Lactate homeostasis responded to pharmacological supplements of lipoic acid. At age 1 year the child was hypotonic, showed severe developmental retardation, optic atrophy and cranial dysmorphism. She died aged 1 year 8 months with signs of respiratory paralysis but with normal lactate levels under assisted breathing. Pathological findings at autopsy were suggestive of Leigh syndrome, interstitial pneumonia and extensive fatty infiltration of hepatocytes. Regression analysis of data from 187 plasma amino acid determinations from the patient over a period of 1 year 8 months revealed a persistent-imbalance involving alanine, glutamic acid, glutamine, proline, citrulline and branched chain amino acids. Aspects of acute and long-term therapy in this patient and some implications of the imbalances in plasma amino acids are discussed.

Effect of cyclosporine on the renal tubular amino acid handling after kidney transplantation.

The renal tubular handling of free amino acids was studied 5-6 weeks after successful renal transplantation (tx) in 20 children treated with CsA and in 10 children treated with azathioprine (Aza). The results were compared with those of 34 control children. The amino-acid clearance studies were performed in combination with short-term inulin clearance. The CsA group revealed a mean inulin clearance of 49 +/- 16.8 ml/min/1.73 m2, the Aza group of 76.9 +/- 18.2, and the controls of 114 +/- 15.6. The plasma amino-acid concentrations were not different between CsA- and Aza-treated groups; however, most of the essential amino acids were lower in transplanted children than in controls. The decrease was correlated with the GFR. The amino-acid-clearance rates were statistically not different between both transplanted groups, but lower values than in controls were found for alanine, glycine, histidine, lysine, and phenylalanine, and significantly higher values for methionine. The fractional clearance rates of most amino acids were significantly elevated in transplanted children compared to controls. In CsA-treated patients, the fractional clearance rates of arginine, glycine, and serine were higher than in Aza-treated patients. No influence of CsA blood levels or rejection episodes on the amino-acid handling were detectable. We conclude that CsA has no specific influence on the renal handling of amino acids. Most disturbances observed depend on the graft function or may be caused by injuries to the graft following the tx procedure.

Renal function after kidney transplantation in children. A comparison of conventional immunosuppression with cyclosporine.

Clearance studies were performed in 32 transplanted children treated with CsA in combination with low-dose prednisolone (CsA group), and the results were compared with those of 29 children transplanted earlier and treated with azathioprine and prednisolone (CIS group). Serum creatinine and urea levels 6 weeks and 1 year after transplantation (Tx) were significantly higher in the CsA than in the CIS group. Clearance studies 6 weeks after Tx exhibited significantly lower rates in the CsA group: Cin = 47 +/- 16.5 versus 83 +/- 25 ml/min/1.73 sqm, CPAH = 271 +/- 110 versus 503 +/- 181 ml/min/1.73 sqm (P less than 0.001). The filtration fractions were not different (19.1 versus 17.1%). The tubular phosphate reabsorption per ml GFR (Tp/Cin) was only slightly lower in the CsA group (0.76 +/- 0.23 mumol/ml versus 0.93 +/- 0.29; P = 0.09). The endogenous glucose clearance rates were equally elevated in both groups and returned to normal after 1 year. The creatinine clearance (Ccr) had dropped in both groups by a mean for 13 ml/min/1.73 sqm between 6 weeks and 1 year after Tx. No correlation was found between the Ccr and the CsA blood levels, but Ccr was inversely correlated with the number of rejection episodes (r = -0.72, P = 0.001). In conclusion, renal allografts in CsA-treated children exhibited a significantly lower function than in CIS-treated children. The effect was related to the global kidney function without any signs of additional tubular toxicity and was apparent within the first weeks after Tx. Thereafter, the decline in graft function was comparable in both groups and could not be related to CsA treatment.

Complete absence of tubular glucose reabsorption: a new type of renal glucosuria (type 0).

Primary renal glucosuria is an inherited defect of tubular glucose reabsorption and usually classified in type A and type B. We now observed a new type in a 15-year-old boy who had a complete absence of tubular glucose reabsorption. His father had a daily glucosuria of 1.1 g/1.73 m2 and his mother of 2.7 g/1.73 m2. Two siblings excreted 0.4 g/1.73 m2 and 0.3 g/1.73 m2 glucose and one sister had no glucosuria. The proband excreted daily 136 to 160 g/1.73 m2 glucose accompanied by normal blood glucose levels between 75-105 mg/dl. The glomerular filtration rate (inulin clearance) was 148-153 ml/min/1.73 m2 and the endogenous glucose clearance was 112-160 ml/min/1.73 m2 when blood glucose levels were 72-82 mg/dl. Thus, glucose clearance was nearly identical to inulin-clearance. After intravenous glucose loading with a blood glucose concentration of 261-342 mg/dl, glucose clearance remained in the same range and tubular glucose reabsorption was virtually absent. There were no disturbances in tubular reabsorption of other substrates. This new type of primary renal glucosuria was not recognized thus far, and we propose to call it type O glucosuria. The family tree revealed consanguinity and most probably the proband is homozygous and both his parents are heterozygous for type O renal glucosuria.

[Screening for congenital metabolic diseases in mentally retarded patients in 6 psychiatric institutions of Lower Saxony]. / Screeninguntersuchungen auf angeborene Stoffwechselerkrankungen bei geistig retardierten Patienten in 6 psychiatrischen Anstalten Niedersachsens.

The results of screening for inborn errors of metabolism in patients in six institutions for the mentally retarded in Lower Saxony are presented. A battery of standard chemical and chromatographic tests for amino acids, carbohydrates and mucopolysaccharides in urine were employed. Combined gas chromatography-mass spectrometry was used to detect organic aciduria. All together 975 patients - 347 females and 628 males - aged from 5 to 93 years were studied. 78.6% of the patients were over 20 years of age. There were positive findings in 56 cases: phenylketonuria (n = 8), alcaptonuria (1), pentosuria (5), galactosuria (2), tryptophanuria (1), xanthurenic aciduria (3), mucopolysaccharidosis type III A (1), hyperglycinemia with hyperglycinuria (1), renal hyperaminoaciduria (9, lactic aciduria (3), 4-hydroxyphenylaceticaciduria (2), organic aciduria (12) and mellituria (8) of unknown type. The organic acids most often detected in urine were lactic, 4-hydroxyphenylacetic and 3-hydroxybutyric acids. Only 20 of the patients (2.0%) excreted appreciable amounts of benzoic acid in urine. The results are discussed and compared with other investigations.

Brain, CSF, and tumor pharmacokinetics of alpha-difluoromethylornithine in rats and dogs.

We have determined the pharmacokinetic parameters for diffusion of alpha-[5-14C]-difluoromethylornithine (DFMO) from blood to brain, blood to cerebrospinal fluid (CSF), 9L rat brain tumor to adjacent brain, and blood to the subcutaneously-implanted 9L tumor in rats, and within the CSF of beagle dogs. DFMO diffusion across the blood-brain and blood-CSF barriers is quite restricted in both rats and dogs, but diffusion across the defective capillary system of both subcutaneous and intracerebral 9L tumors in rats is not. Under steady-state plasma conditions in rats, uptake of DFMO by the intracerebral 9L tumor and diffusion from tumor 5-6 mm into adjacent brain is not restricted; tissue/plasma ratios were approximately 1. Therapeutic efficacy will therefore not be limited by transport of DFMO into tumor or to the extracellular environment of tumor.