A new doping control screening method has been developed, for the analysis of doping agents in human urine, using HPLC/orbitrap with in‐source collision‐induced dissociation and atmospheric pressure chemical ionization. The developed method allows the detection of 29 compounds, including agents with antiestrogenic activity, β₂ agonists, exogenous anabolic steroids, and other anabolic agents. The mass accuracy of this method is better at 2 ppm using an external reference. The detection limit for all compounds tested was better than 100 pg/ml. The recoveries of most analytes were above 70%. The measured median repeatability values for doping agents included in the method at concentrations of 1 and 10 ng/ml were 21 and 17%, respectively. The relative standard deviation (RSD) of the intraday precision (n = 6) ranged from RSD = 16–22%, whereas the interday precision (n = 18), ranged from RSD = 17–26%, depending on the solute concentration investigated. Copyright © 2008 John Wiley & Sons, Ltd.

Objective: Recent studies have shown that cerebral ischaemia causes not only local, but also systemic oxidative stress. This leads to oxidation of thiol-containing compounds, including low-molecular-weight thiols (cysteine, glutathione, homocysteine and others). Therefore, the aim of this work was to verify the hypothesis that the thiol/disulphide homeostasis of low-molecular-weight thiols is disturbed in the early stages of cerebral ischaemia. Methods: Two experimental rat models of ischaemia were used: a global model of vascular ischaemia (clamping the common carotid arteries + haemorrhage) and focal ischaemia (middle cerebral artery occlusion). The total levels of thiols and their reduced forms were measured before surgery and after 40 minutes of reperfusion (global) or 3 hours (focal) ischaemia. Results: The global ischaemia model caused a marked (2.5–4 times, P < 0.01) decrease in the plasma thiol/disulphide redox state, and focal ischaemia caused an even larger decrease (30–80 times, P < 0.001). Discussion: These results suggest that plasma low-molecular-weight thiols are actively involved in oxidation reactions at early stages of cerebral ischaemia; therefore, their reduced forms or redox state may serve as a sensitive indicator of acute cerebrovascular insufficiency.

Acute brain ischemia is accompanied by a disruption of low-molecular-weight aminothiols (LMWTs) homeostasis, such as homocysteine (Hcy), cysteine (Cys), and glutathione (GSH). We investigated the r...