We have established normal values for calcium/creatinine (Ca/Cr) and oxalate/creatinine (Ox/Cr) ratios in 25 infants (aged 1-7 days) and 391 children (aged 1 month to 14.5 years) and compared these with values obtained in 137 children with post-glomerular haematuria and 27 with nephrolithiasis. Oxalate was measured by ion chromatography. Nomograms of Marshall and Robertson were used to calculate urine saturation to calcium oxalate. The Ca/Cr ratio was normally distributed whereas the Ox/Cr ratio had a log-normal distribution. The molar ratio of Ca/Cr was the lowest in the first days of life and the highest between 7 month and 1.5 years (mean +/- SD = 0.39 +/- 0.28 mmol/mmol). Following a slight decrease it stabilised by the age of 6 years (0.34 +/- 0.19 mmol/mmol). The highest Ox/Cr values were measured during the 1st month of life [geometric mean 133 (range 61-280) mumol/mmol], followed by a gradual decrease until 11 years of age [mean 24 (range 6-82) mumol/mmol]. Thirty-six haematuric children had hypercalciuria (26%), 23 had absorptive hypercalciuria, 13 renal type. Children with absorptive hypercalciuria on a calcium-restricted diet had significantly higher oxalate excretion than those with renal hypercalciuria and the control group [38 (range 28-49) vs. 22 (range 16-29) and 23 (range 22-27) mumol/mol respectively, P < 0.01]. Calcium oxalate urine saturation of stone patients was higher than that of patients with haematuria and the normal population (1.18 +/- 0.05 vs. 1.06 +/- 0.03, P < 0.03 and 0.84 +/- 0.03, P < 0.001 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

24 Hour ambulatory blood pressure monitoring (ABPM) was performed to provide data on the normal daily blood pressure of healthy schoolchildren and on patients with hypertension. The subjects studied were 123 healthy schoolchildren with a mean (SD) age of 12-5 (1-6) years (range 9-5-14-5 years), 24 children with borderline or mild hypertension, 17 with renal hypertension and normal renal function, 10 with chronic renal failure, and six with a renal allograft. In eight children with definite renal disease a second measurement was performed after treatment modification.The monitor used for ABPM was validated with a mercury column manometer. The mean (SD) of the signed differences ofthe blood pressure measured by the two methods was -0-19 (1-75) mm Hg for the systolic and -0-21 (2.11) mm Hg for the diastolic blood pressure (n=60). Normal values for daytime and night time blood pressure were determined for those aged 10-14 years. The mean (SD) blood pressure of the 123 children was 109 (7)/66 (8) mm Hg (systolic/diastolic) for the daytime and 96 (8)/52 (7) mm Hg at night time. Ofthe 24 children with borderline or mild hypertension 14 had a raised blood pressure on ABPM. The circadian rhythm was disturbed in three children of this group. Even children with normal daytime blood pressure had significantly higher systolic blood pressure in the night when compared with the controls. The incidence of disturbed circadian rhythm was higher in the groups with renal hypertension (4/17 in the subgroup with normal renal function, 5/16 in the group with renal failure and/or transplantation). All children undergoing a second ABPM measurement had a lower average blood pressure after treatment adjustment.ABPM measurements were reproducible and accurate. The method provided new data on the physiological circadian variation of blood pressure in healthy children. It proved to be a helpfil tool in the diagnosis of hypertension, particularly in the detection of cases of disturbance of the circadian rhythm of blood pressure pattern and individual adjustment oftreatment. (Arch Dis Child 1994; 70: 90-94)

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SUMMARY Tubular function was investigated in patients with diabetic ketoacidosis and those with poorly controlled type I diabetes. Urinary excretion of beta2 microglobulin and that of certain enzymes: y glutamyltransferase, leucine aminopeptidase, and N-acetyl-,3-Dglucosaminidase activities were significantly raised during ketoacidosis in 11 patients compared with healthy controls. In 13 poorly controlled diabetics, tubular electrolyte transport was studied and a significant reduction in tubular phosphate and sodium reabsorption was found. Tubular dysfunction occurring during diabetic ketoacidosis and in poorly controlled diabetics may contribute to the development of diabetic nephropathy.In an earlier study we found reversible tubular proteinuria in diabetic children during hyperglycaemic ketoacidosis. 1 In the present study further aspects of tubular dysfunction were investigated. PatientsUrinary excretion of beta2 microglobulin and of certain enzymes was investigated in three groups of patients:(i) Eleven diabetics with ketoacidosis, aged mean (SD) 9-6 (3.7) years, who had had diabetes for 1-4 (1.7) years. Six of the patients were newly diagnosed and five had been diabetic for less than five years. At the start of our investigation the blood glucose concentration for the entire group was mean (SD)22-2 (8.8) mmolUl. Glycosuria of 520 (330) mmol/day was found. Mean blood pH was 7-12 (0.10) with a base excess of -21.8 (5.2) mmoIIl.(ii) Thirteen well controlled diabetic children who had a HbAlc of less than 9-5%. Their age was 10-3 (3-0) years, and the mean duration of diabetes in this group was 2-4 (2-7) years.(iii) Eighteen healthy children aged 12-0 (3.4)years, who served as controls. In 13 poorly controlled diabetics renal tubular electrolyte transport was tested during water loading. Their age was 12 7 (2-25) years, and the mean duration of diabetes in this group was 4-3 (3-4) years. These children had a HbAlc of 12 5 (2.7)%.Seven of 13 were just recovering from ketoacidosis. Water loading was also performed in 11 healthy children.

Endothelin is a peptide with vasoactive and diuretic potential. Its release has been demonstrated from endothelial and renal epithelial cells. Urinary excretion of endothelin, as shown by others, is thought to reflect intrarenal production. We measured endothelin by RIA in a population of healthy children from Germany and Hungary (group 1), neonates (group 3) and children before and during forced diuresis (groups 2a and 2b). Group 1 consisted of 24 children living in Germany and 13 children resident in Hungary. The age range in this group was 2.9-17 years. Daily excretion correlated significantly with age (r = 0.48, p < 0.001), but endothelin excretion corrected for body surface area remained constant with regard to the age group studied. This indicates that body or kidney size may influence endothelin excretion, respectively. There was no difference in endothelin excretion between the two countries. In premature infants and neonates (group 3), daily excretion of endothelin was highest in infants with very low gestational ages and decreased in full-term neonates to values not significantly different to the group of older children. The high values in premature infants may have been influenced by mechanical ventilation of physical stress, which cannot be differentiated in this study, however. In contrast to reported results in adults, renal excretion of endothelin was correlated positively to urine flow in all groups. Furthermore, the influence of forced diuresis was evaluated in 10 children with oncological disease before (group 2a) and during (group 2b) forced diuresis with fluid load (3 l/m2; n = 4) and fluid load with furosemide injection (0.3-1.0 mg/kg body weight; n = 6).(ABSTRACT TRUNCATED AT 250 WORDS)