1. Laboratories of Chemistry, Biochemistry, Department of Biosciences, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland, Department of Pharmaceutics, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland, Department of Immunology, Faculty of Medicine, University of Manitoba, Winnipeg, Manitoba R3E 0W3, Canada