[1] Univ Maryland, Dept Chem & Biochem, College Pk, MD 20742 USA
[2] Massachusetts Gen Hosp, Dept Anesthesia Crit Care & Pain Med, Boston, MA 02114 USA
[3] Harvard Univ, Sch Med, Boston, MA USA
[4] Tech Univ Munich, Klin Anaesthesiol, Klinikum Rechts Isar, D-81675 Munich, Germany
[5] Essen Duisburg Univ, Dept Anesthesia & Intens Care Med, Duisburg, Germany