Evidence for disturbed regulation of calciotropic hormone metabolism in gitelman syndrome.

Little attention has been paid to interactions between circulating levels of calcium, PTH, and 1,25-dihydroxycholecalciferol [1,25(OH)2D] and bone mineral density in primary renal magnesium deficiency. Plasma and urinary electrolytes, and circulating levels of calciotropic hormones were studied in 13 untreated patients with primary renal tubular hypokalemic alkalosis with hypocalciuria and magnesium deficiency. The blood ionized calcium concentration was significantly lower in patients than in controls. Despite this fact, PTH and 1,25-(OH)2D levels were similar in both groups of subjects. The negative linear relationships between PTH and ionized calcium, which significantly differed between Gitelman patients and healthy subjects in terms of intercept; the negative relationship between ionized calcium and 1,25-(OH)2D, which was comparable in both groups; and the positive relationship between 1,25-(OH)2D and PTH, which was identical in both groups, point both to a blunted secretion of PTH induced by magnesium depletion and to the lack of interference of the latter with the activation of 1 alpha-hydroxylase by PTH. The similar bone mineral density at the lumbar spine by dual energy x-ray absorptiometry in 11 patients and 11 healthy subjects argues against chronically sustained negative calcium balance.

Long-term follow-up of a patient with Gitelman's syndrome.

The long-term follow-up (from age 6 to 20 years) of a girl with Gitelman's syndrome, who had four hypomagnesaemic-tetanic episodes associated with normal plasma calcium, hypokalemia and hypocalciuria, is presented. During and after puberty, hypomagnesaemia was of the order of 0.41-0.49 mmol/l and plasma potassium was at the lower reference limit. The long-term clinical course and growth of this patient appeared good, but, magnesium supplementation reduces the risk of tetanic crises.

Evaluation of the peritoneal equilibration test in children on chronic peritoneal dialysis.

The peritoneal equilibration test (PET) is routinely performed in adults treated with chronic peritoneal dialysis to assess the peritoneal transport rate and to optimize treatment prescription. Only a few and not well-standardized studies on the PET have been reported in children. Twenty-six PET's were performed in 16 children, mean age 10.9 +/- 4.9 years, mean body weight (BW) 26.8 +/- 11.9 kg, treated with nightly intermittent peritoneal dialysis (NIPD). The PET was performed according to Twardowski. Forty mL/kg BW of 2.27% glucose solution were infused at a rate of 10 mL/kg BW every 2 minutes. In the simplified test, dialysate samples were taken at dwell times 0, 2 and 4 hours for glucose and creatinine. A blood sample was taken after a 2-hour dwell time for the same parameters. The standard PET (8 patients) consisted of dialysate samples at 0, 15, 30, 60, 120, and 240 minutes and blood samples at 0 and 240 minutes. Mean D/P ratio for corrected creatinine and D/D0 ratio for glucose at 2 hours were 51.6 +/- 11.6 and 50.4 +/- 9, respectively; at 4 hours 69.6 +/- 12 and 34.4 +/- 9.8, respectively. There was good correlation between D/P creatinine and D/D0 glucose at 4 hours (p < 0.0001). Patients were classified as high (3 cases), high-average (5), low-average (6), and low (2) transporters. A statistically significant difference was found between the curves obtained by the simplified PET and those of the standard PET in the first hour (r = 0.66; p < 0.05). In conclusion, the PET, modified for use in children, gave reliable and reproducible results.(ABSTRACT TRUNCATED AT 250 WORDS)

[Procedure for identifying atypical variants of pseudocholinesterase for the prevention of prolonged apnea induced by succinylcholine]. / Procedimento per l'individuazione delle varianti atipiche della pseudocolinesterasi ai fini della prevenzione dell'apnea protratta indotta dalla succinildicolina.

The simple Sclavo test based on succinyldicholine hydrolysis and on the following reaction with 5,5'-dithio-bis-2-nitrobenzoic acid for detection of the atypical patterns of serum cholinesterase has been investigated. A yellow staining appears but in presence of the atypical forms of the enzyme. Analysis of 4055 serum samples by the 430 Selective Analyzer Sclavo allowed the identification of one atypical homozygous patient. Prolonged apnoea induced by use of succinyldicholine as a neuromuscular blocking agent during anaesthesia may be avoided by use of this test.

[Evaluation of a colorimetric enzymatic method for the determination of sialic acid in serum]. / Valutazione di un metodo enzimatico colorimetrico per la determinazione dell'acido sialico nel siero.

Evaluation of sialic acid in serum was done by means of an enzymatic colorimetric method using the Biochemia Sialic Acid kit. Precision and accuracy within-run and run-to-run were high and linearity was observed just to a 170 mg/dl concentration. Reference values evaluated in 2700 samples were: mean = 65.3 mg/dl; mean +/- 2 standard deviations = 52.0-78.6 mg/dl.