Preservation of urine free catecholamines and their free O-methylated metabolites with citric acid as an alternative to hydrochloric acid for LC-MS/MS-based analyses.

Background: Measurements of urinary fractionated metadrenalines provide a useful screening test to diagnose phaeochromocytoma. Stability of these compounds and their parent catecholamines during and after urine collection is crucial to ensure accuracy of the measurements. Stabilisation with hydrochloric acid (HCl) can promote deconjugation of sulphate-conjugated metadrenalines, indicating a need for alternative preservatives.

Levodopa therapy in Parkinson's disease: influence on liquid chromatographic tandem mass spectrometric-based measurements of plasma and urinary normetanephrine, metanephrine and methoxytyramine.

Background: Medication-related interferences with measurements of catecholamines and their metabolites represent important causes of false-positive results during diagnosis of phaeochromocytomas and paragangliomas (PPGLs). Such interferences are less troublesome with measurements by liquid chromatography with tandem mass-spectrometry (LC-MS/MS) than by other methods, but can still present problems for some drugs. Levodopa, the precursor for dopamine used in the treatment of Parkinson's disease, represents one potentially interfering medication.

Reference intervals for plasma free metanephrines with an age adjustment for normetanephrine for optimized laboratory testing of phaeochromocytoma.

Background: Measurements of plasma normetanephrine and metanephrine provide a useful diagnostic test for phaeochromocytoma, but this depends on appropriate reference intervals. Upper cut-offs set too high compromise diagnostic sensitivity, whereas set too low, false-positives are a problem. This study aimed to establish optimal reference intervals for plasma normetanephrine and metanephrine.

Time-dependent release of cobalt and chromium ions into the serum following implantation of the metal-on-metal Maverick type artificial lumbar disc (Medtronic Sofamor Danek).

Introduction: In total hip endoprosthetics and consequently for TDA, metal-on-metal combinations are used with the aim of reducing wear debris. In metal-on-metal TDA the release of metal ions has until now been secondary to the main discussion.

Materials And Methods: In order to investigate the ion release following the implantation of the metal-on-metal Maverick type artificial lumbar disc we measured the serum cobalt and chromium concentration following implantation of 15 Maverick TDAs (monosegmental L5/S1, n = 5; bisegmental L4/5 and L5/S1, n = 5; average age 36.

On interaction of activated protein C with human aortic smooth muscle cells attenuating the secretory group IIA phospholipase A2 expression.

Introduction: Pharmacological restriction of secretory group IIA phospholipase A(2) (sPLA(2)-IIA) expression is thought to be beneficial in the treatment of inflammatory diseases such as sepsis and septic shock. In this study we investigated the effects of activated protein C (APC) on sPLA(2)-IIA expression, phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, and on DNA-binding activities of nuclear factor-kappaB (NF-kappaB) and CCAAT box enhancer binding protein-beta (C/EBP-beta) in human aortic smooth muscle cells (HASMC).

Materials And Methods: To achieve elevated sPLA(2)-IIA production as occurring during inflammation, HASMC were stimulated with interferon-gamma (IFN-gamma) alone and in combination with other inductors, thus modeling the strong sPLA(2)-IIA elevation by inflammation.