1. Department of Molecular Medicine, National Public Health Institute, Biomedicum Helsinki, PO Box 104 Haartmaninkatu 8 00251 Helsinki Finland
2. Institute of Clinical Neuroscience, Göteborg University, Sahlgrenska University Hospital/Mölndal SE 43180 Molndal Sweden
3. Department of Biosciences, Division of Biochemistry, Viikki Biocenter, University of Helsinki, PO Box 56 00014 Helsinki Finland