1. Uppsala University; Department of Medicinal Chemistry, Division of Analytical Pharmaceutical Chemistry, Biomedical Centre; Husargatan 3 PO Box 574 SE-751 23 Uppsala Sweden
2. Dept. of Companion Animal Clinical Sciences; Norwegian School of Veterinary Science; PO Box 8146, N-0033 Oslo, Norway, and Blåstjärnans Djursjukhus, Gjutjärnsgatan 4 SE-417 07 Gothenburg Sweden
3. Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine; Ghent University; Salisburylaan 133 9820 Merelbeke Belgium