Evaluation of specific high-performance liquid-chromatographic determinations of urinary adrenaline and noradrenaline by comparison with isotope dilution mass spectrometry

A method for the determination of metadrenaline (MA). normetadrenaline (NMA) and 3-methoxytyramine (3-MT) in human urine using high-performance liquid chromatography followed by electrochemical detection (ECD) was validated primarily by comparing the results with those obtained by a gas chromatography mass spectrometry (GC MS) reference method. Correlation coefficients of 0.93, 0.94 and 0.91 were obtained for MA, NMA and 3-MT. respectively, in a group of healthy controls consisting of 30 women and 30 men. A systematic difference wits detected only for 3-MT (-16%). Further tests Of accuracy (linearity and recovery) and precision demonstrated that the described method must be considered to be a reliable approach to assess urinary metadrenalities in the diagnosis of phaeochromocytoma. At lower concentrations (MA, 248 nmol L; NMA. 434 nmol, L; 3-MT, 402 nmol/L), within-assay coefficients of variation were close to 5%, or less (5(.)3, 4(.)6 and 2(.)2%, respectively) and between-assay, Coefficients Of Variation were 8(.)9. 11(.)2 and 12(.)3%, respectively, for the same low levels. This raises the possibility that this method can also be applied to assess urinary free, unconjugated metanephrines. Sex differences were detected for MA and NMA excretion Mien expressed in nmol per 24h and nmol/mmol creatinine, respectively, by both ECD and GC MS methods

Exon skipping in the sterol 27-hydroxylase gene leads to cerebrotendinous xanthomatosis

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Comparison of near infrared reflectance analysis of fecal fat, nitrogen and water with conventional methods, and fecal energy content

Comparison of near infrared reflectance analysis of fecal fat, nitrogen and water with conventional methods, and fecal energy content. Neucker AV, Bijleveld CM, Wolthers BG, Swaaneburg JC, Kester AD, Kreel B, Forget PP. Department of Pediatrics,University Hospital Maastricht, 6202 AZ, Maastricht, The Netherlands. [email protected] OBJECTIVES: To evaluate Near-Infrared Analysis (NIRA) method for determining fecal fat, water and nitrogen. DESIGN AND METHODS: The results of fecal fat, water and nitrogen by NIRA were compared with results of van de Kamer and Acid Steatocrit (AS), Dumas and vacuum drying methods for fat, nitrogen and water respectively.Results of fat determining methods were also compared with total fecal energy as obtained by bomb calorimeter. RESULTS: NIRA results correlated significantly (p < 0.001) with standard methods for nitrogen (r = 0.79), fat (r = 0.84 and r = 0.88 for van de Kamer and AS respectively) and water (r = 0.91). The limits of agreement for nitrogen and fat results were too wide for the methods to be used interchangeably. The fecal fat results correlated significantly (p < 0.001) with fecal energy results. CONCLUSION: NIRA may be valuable for monitoring malabsorption but the diagnostic value remains to be determined

Malabsorption of liposoluble vitamins in a child with bile acid deficiency

A male born to first cousins presented at 12 months with hypocalcemic convulsions, rickets, epistaxis due to vitamin K deficiency, and extremely low serum levels of beta-carotene and vitamin A. Liver function was altered moderately (glutamic-oxaloacetic transaminase, 55 U/L; glutamic-pyruvic transaminase, 37 U/L; lactate dehydrogenase, 255 U/L; alkaline phosphatase, 437 U/L). To correct the deficiencies, 8000 IU vitamin D/day, 10,000 IU vitamin A/day, and intramuscular administration of vitamin K1 were required. At 9 years, he presented signs of neuromuscular affection, and the serum vitamin E level (measured for the first time) was extremely low. Classic lipid malabsorption syndromes (abetalipoproteinemia, chronic cholestasis, mucoviscidosis, coeliac disease, Whipple's disease) were excluded by appropriate examinations. Composition of duodenal bile acids was characterized by undetectable levels of cholic acid metabolites, and only chenodeoxycholic acid metabolites were present. Serum total bile acid concentration was normal, with an atypical low cholic acid/chenodeoxycholic acid ratio and abnormal presence of 3β-OH-Δ5-cholenic acid and 6-OH-bile acids. Urinary bile acid composition was also characterized by elevated 6-OH-bile acids. Known enzymopathies of the bile acid synthetic pathway were excluded (cerebrotendinous xanthomatosis, cerebro-hepato-renal syndrome of Zellweger, coprostanic acidemia). Bile acid pool sizes were determined by using stable isotopes: cholic acid pool size [2.90 (N, 32 ± 16) μM/kg] and chenodeoxycholic acid pool size [10.8 (N, 32.6 ± 9.9) μM/kg] were extremely low; fractional turnover rates of both bile acids were in a normal range. Treatment with chenodeoxycholic acid markedly improved the absorption of fat soluble substances and normalized hepatic function. A partial enzyme defect in the metabolism of the steroid nucleus is proposed.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Effect of simvastatin in addition to chenodeoxycholic acid in patients with cerebrotendinous xanthomatosis

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