1. Department
of Analytical Biochemistry, University of Groningen, Antonius Deusinglaan
1, 9713 AV Groningen, The Netherlands
2. University Medical Centre Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
3. Department
of Neurology, Erasmus University Medical Center, P.O. Box 1738, 3000DR Rotterdam, The Netherlands