Changes in vitamin-D metabolites and parathyroid hormone in plasma following cholecalciferol administration to pre- and postmenopausal women in the Netherlands in early spring and to postmenopausal women in Curacao

To study the effect on plasma 25-hydroxycholecalciferol (25(OH)D), 1, 25-dihydroxycholecalciferol (1, 25(OH)(2)D) and parathyroid hormone (PTH) we supplemented premenopausal (aged 30 (so 7) years) and postmenopausal (aged 61 (so 2) years) white women living in The Netherlands in late winter/early spring, and elderly black and white women (aged 75 (so 6) years) living in Curacao (Dutch Antilles) with either 10 or 20 mu g cholecalciferol/d for 4, 5 and 9 weeks respectively, Baseline plasma 25(OH)D concentration of Dutch women was lower than that of Curacao women, Postmenopausal Dutch women had a higher PTH concentration in plasma than premenopausal Dutch and postmenopausal Curacao women, There were no differences in plasma 1,25(OH),D, Cholecalciferol administration increased 25(OH)D in all groups, 1, 25(OH),D in postmenopausal Curacao women and PTH in postmenopausal Curacao women and premenopausal Dutch women, Serum and urinary Ca and phosphate concentrations did not change, There were no response differences between 10 and 20 mu g doses, Oral cholecalciferol administration (either 10 or 20 mu g/d) to women living at northern latitudes in late winter/early spring increased 25(OH)D levels to the baseline levels of elderly people living in the tropics

Development of a proton-transfer reaction ion trap mass spectrometer: Online detection and analysis of volatile organic compounds

Contains fulltext : 34910.pdf (publisher's version ) (Closed access)The development of a new proton-transfer reaction ion trap mass spectrometer (PIT-MS) from a commercially available ion trap system is presented and the advantages of using an ion trap over a quadrupole mass filter are explored. For our PIT-MS we determine the optimal kinetic energy parameter E/N (95 Td) to be significantly lower than for the more conventional proton-transfer reaction mass spectrometer (PTR-MS) (120 Td) with a quadrupole mass filter. This gives a theoretical increase in sensitivity of similar to 25% with respect to the generally used 120 Td. The limits of detection of the PIT-MS are still one order of magnitude higher than for the PTR-MS system, but better detection electronics are thought to improve this in the near future. The PlT-MS system is tested in a comparison with our PTR-MS on measurements of volatile compounds from an Elstar apple, where we show the time behavior and concentration determination of the PIT-MS to be reliable. In this comparison, we also show the applicability of and problems related to the use of collision induced dissociation (CID) analysis for the identification of compounds. The lower degree of fragmentation upon proton transfer is identified as an additional advantage of the use of low E/N-values. (C) 2006 Elsevier B.V. All rights reserved

The impact of laboratory closing times on delay of adequate therapy in blood stream infection

BACKGROUND: Patients with bloodstream infections need early adequate antimicrobial treatment to reduce mortality. This raises the question of timing and logistics. How important is the time of day when a culture is flagged positive to the processing of blood cultures and optimisation of antimicrobial therapy? METHODS: We performed a retrospective study assessing the time delay of a positive blood culture result during and after office hours and its impact on adequate antimicrobial therapy. Process duration from the moment of culture positivity to Gram stain completion was compared at different timepoints during the day in a medium-sized hospital with an offsite microbiological laboratory. RESULTS: Ninety-four patients with positive, noncontaminated blood cultures were included. Sixty-six patients (70%) received adequate empirical therapy; this increased to 76 cases (82%) and to 88 cases (95%) after analysis of Gram stain results and complete determination, respectively (p < 0.05 for all comparisons). Median duration from culture positivity to Gram stain completion (including offsite culture transport) increased from a median of four to 12 hours if time of cultures turned positive after office hours (p < 0.05), irrespective of the adequacy of empirical coverage. This also resulted in a median 12-hour delay for the complete process from time of culture positivity to administration of the antimicrobial drug (p < 0.05). CONCLUSION: Processing blood cultures after office hours is often deferred, which can lead to a delay in adequate antimicrobial therapy for patients with bloodstream infections