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Background Accurate measurement of 17-hydroxyprogesterone (17-OHP) concentrations is essential for the correct diagnosis and treatment management of children with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21 OHD). Methods We analysed 102 serum samples from 15 children with known 21 OHD twice using two different 17-OHP assays. 17-OHP concentrations were measured by an in-house radioimmunoassay (RIA) after recovery-corrected extraction and chromatographic purification and by a commercially available RIA without extraction (Immunotech). Results The correlation coefficient for results of pairs of 17-OHP concentrations was 0.974. The median ratio (17-OHP concentration measured with the commercial assay/17-OHP concentration measured with the in-house assay) was 0.593 with a 95% confidence interval ranging from 0.258 to 1.370. The ratio was constant throughout the average 17-OHP concentrations ranging from 0.24 to 149.2 nmol/L, as well as throughout the age range from 0.3 to 16.4 years. Conclusions Despite good overall correlation, absolute 17-OHP concentrations differed dramatically. This could lead to misclassification of patients suspected for 21 OHD on the basis of the hormonal profile and to a reduced quality during treatment monitoring of patients with 21 OHD with the risk of under- and overtreatment.

The mitochondrial phosphate carrier SLC25A3 transports inorganic phosphate into the mitochondrial matrix, which is essential for the aerobic synthesis of adenosine triphosphate (ATP). We identified a homozygous mutation--c.215G--A (p.Gly72Glu)--in the alternatively spliced exon 3A of this enzyme in two siblings with lactic acidosis, hypertrophic cardiomyopathy, and muscular hypotonia who died within the 1st year of life. Functional investigation of intact mitochondria showed a deficiency of ATP synthesis in muscle but not in fibroblasts, which correlated with the tissue-specific expression of exon 3A in muscle versus exon 3B in fibroblasts. The enzyme defect was confirmed by complementation analysis in yeast. This is the first report of patients with mitochondrial phosphate-carrier deficiency.

Objectives: Our purpose was to characterize the decisive pathophysiologic factors that lead to renal stone formation (nephrolithiasis) in patients with cystic fibrosis (CF). Methods: Patients with CF (n = 96) were investigated with respect to lithogenic and inhibitory factors of urolithiasis and compared with 30 healthy control patients. They were subdivided into 2 groups, 86 without renal stones and 10 with renal stones. Results: All stones were exclusively composed of calcium oxalate. As a major pathogenic factor, a urinary disequilibrium between promoting and inhibitory components of stone formation, characterized mainly by hypercalciuria, hyperoxaluria, and hypocitraturia, was found in the patients with nephrolithiasis. They tended to have lower plasma phosphate concentrations and an increased urinary phosphate excretion. The citrate/calcium ratio proved to be a valuable means to discriminate patients with renal stones from control patients. Patients with stones had ingested more cotrimoxazole and ceftazidim, cumulatively, than patients without stones. There was an inverse correlation between the amounts of antibiotics ingested and the percentage of tubular phosphate reabsorption ( r = –0.91, P Conclusion: Renal stone formation in patients with CF is caused by a disequilibrium between promoting and inhibitory components of stone formation, which is dominated by hypercalciuria, hyperoxaluria, and hypocitraturia. Treatment with cotrimoxazole and ceftazidim, primarily, may lead to renal proximal tubular damage with an ensuing sequence of phosphate loss, increase of parathyroid hormone secretion, increased 1,25-dihydroxyvitamin D3 formation, and absorptive hypercalciuria. (J Pediatr 2002;140:103-9)

Nitric oxide modulates expression of matrix metalloproteinase-9 in rat mesangial cells Background High-output levels of nitric oxide (NO) are produced by rat mesangial cells (MCs) in response to proinflammatory cytokines such as interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) by the inducible isoform of NO synthase (iNOS). We tested modulatory effects of NO on the expression and activities of matrix metalloproteinases-9 and -2 (MMP-9 and MMP-2), respectively. Temporal and spatial expression of these MMPs and their specific inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), seems to be critical in the extensive extracellular matrix (ECM) remodeling that accompanies sclerotic processes of the mesangium. Methods and Results. Using the NO donors S-Nitroso-N-acetyl-D,L-penicillamine (SNAP) and DETA-NONOate, we found strong inhibitory effects of NO mainly on the IL-1β–induced MMP-9 mRNA levels. NO on its own had only weak effects on the expression of MMP-9 and MMP-2. The addition of the NOS inhibitor N G -monomethyl L-arginine (L-NMMA) dose dependently increased steady-state mRNA levels of cytokine-induced MMP-9, suggesting that endogenously produced NO exerts tonic inhibition of MMP-9 expression. MMP-9 activity in conditioned media from MCs costimulated with IL-1β and NO donor contained less gelatinolytic activity than media of cells treated with IL-1β alone. Exogenously added NO did not alter gelatinolytic activity of MMP-9 in cell-free zymographs. The expression levels of TIMP-1 were affected by NO similarly to the expression of MMP-9. Conclusion We conclude that NO modulates cytokine-mediated expression of MMP-9 and TIMP-1 in rat MCs in culture. Our results provide evidence that NO-mediated attenuation of MMP-9 gelatinolytic activity is primarily due to a reduced expression of MMP-9 mRNA, and not the result of direct inhibition of enzymatic activity.

Newborns (n = 84) from families with a positive history for atopic dermatitis were pro-spectively investigated. 71 children were exclusively breast fed (group A), whereas 13 (group B) received a partial whey protein hydrolysate (Beba HA; Nestle AG) for up to maximally the first six weeks of life and were also exclusively breast fed thereafter. All mothers were instructed to use only food stuffs of low allergen content. After 12 months, 12 children (17 %) in group A had developed atopic dematitis whereas none in group B showed any atopic signs. After 18 months 23% of the children in group A showed manifestations of atopic dermatitis. In group B still no child showed disease symptoms. These results support the idea of tolerance by ingestion of 2 to 10 kD proteins during the early weeks of life.

In patients with methylmalonic aciduria (MMA), the accumulating metabolite propiony-CoA results in an inhibition of the urea circle via the decreased synthesis of N-acetylglutamate, an essential activator of carbamylphosphat synthetase (CPS). This results in one of the major clinical problems which is hyperammonaemia. In a patient with decompensated MMA, the CPS activator carbamylglutamate was tested for its ability to antagonize the propionyl-CoA-induced hyperammonaemia. Oral carbamylgutamate administration resulted in an impressive increase in ammonia detoxification compared to peritoneal dialysis. Safe, fast and easy to administer, carbamylglutamate improves the acute therapy of decompensated MMA by increasing ammonia detoxification and avoiding hyperammonaemia.