1. Institute of Anatomy; Medical Academy Magdeburg; Leipziger Str. 44 DDR-3090 Magdeburg G.D.R.
2. Institute of Neurobiology and Brain Research of the Academy of Science; Magdeburg G.D.R.
3. Department of Biochemistry; University of Oulu; Finland
4. Department of Pathology; University of Oulu; Finland