1. Denator AB, Uppsala Science Park, Dag Hammarskjölds väg 32a, 751 83, Uppsala, Sweden, Department of Pharmaceutical Biosciences, Medical Mass Spectrometry, Uppsala University, Box 583, 751 23 Uppsala, Sweden, Department of Physiology and Pharmacology, Karolinska Institutet, Nanna Svartz väg 2, 171 77 Stockholm, Sweden, and Department of Pharmaceutical Biosciences, Division of Toxicology, Uppsala University, Box 594, 751 24 Uppsala, Sweden