RÉSUMÉ
BACKGROUND: Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders that occur due to defects in the steroidogenesis pathway. Approximately 90% of CAH cases can be diagnosed by the measurement of serum 17-hydroxyprogesterone alone. However, the quantification of six additional steroids could significantly improve CAH laboratory diagnosis. Using dried blood spot (DBS) as specimen of choice can further improve patient care due to the small sample volume required for CAH diagnosis in neonates. METHODS: An optimized DBS sample preparation method was employed for steroids quantification without the need of derivatization. A LC-MS/MS assay was developed and optimized using a reverse phase-ultra high-pressure liquid chromatography (RP-UHPLC) system combined with triple quadrupole mass spectrometry using positive electrospray ionization mode. RESULTS: The assay was validated according to CLSI analytical guidelines, including lower limit of quantification (LLOQ), linearity, precision, accuracy, carryover, and method comparison. The analytical measuring range of the method for all steroids was 2.5, 5, or 10 ng/ml to 250 ng/ml in DBS, r2 ≥ 0.995. The LLOQ, intra-day and inter-day precision were 0.11-1.8 ng/ml, 1.2-6.4 ng/ml, 1.8-11.5%, and 5.3-13.8%, respectively. CONCLUSIONS: Our LC-MS/MS assay simultaneously detects 7 steroids for the diagnosis of CAH and can be readily implemented in clinical laboratories to provide superior analytical performance over traditional immunoassays.
Sujet(s)
Hyperplasie congénitale des surrénales , Spectrométrie de masse en tandem , 17alpha-Hydroxyprogestérone , Hyperplasie congénitale des surrénales/diagnostic , Chromatographie en phase liquide à haute performance , Chromatographie en phase liquide , Dépistage sur goutte de sang séché , Humains , Nouveau-né , Reproductibilité des résultats , StéroïdesRÉSUMÉ
Asthma is characterized as a chronic inflammatory process. Pycnogenol((R)), a bioflavonoid mixture extracted from Pinus maritima, is known to scavenge free radicals while possessing antioxidant and antiinflammatory properties. The objective of this study was to evaluate the efficiency of this agent in a randomized, double-blinded, placebo-controlled, crossover study in patients with varying asthma severity. Twenty-six patients who fulfilled the American Thoracic Society criteria for asthma were enrolled in the study. Medical history, physical examination, blood sample analyses, and spirometric values were obtained at baseline, 4 weeks, and 8 weeks. The patients were randomly assigned to receive either 1 mg/lb/day (maximum 200 mg/day) Pycnogenol or placebo for the first period of 4 weeks and then crossed over to the alternate regimen for the next 4 weeks. No adverse effects were observed related to the study drug. Within the contingent of 22 patients who completed the study, almost all responded favorably to Pycnogenol in contrast to placebo. Pycnogenol treatment also significantly reduced serum leukotrienes compared with placebo. The results of this pilot study indicate that Pycnogenol may be a valuable nutraceutical in the management of chronic asthma. We recommend that further clinical trials be conducted in larger groups of asthmatics to establish its efficacy.