[1] UNIV HOSP ZURICH,DEPT NEUROL,NEUROL CLIN,CH-8091 ZURICH,SWITZERLAND
[2] UNIV HOSP ZURICH,DEPT NEUROSURG,CH-8091 ZURICH,SWITZERLAND
[3] ROYAL POSTGRAD MED SCH,DEPT HISTOCHEM,LONDON W12 0HS,ENGLAND
[4] ROYAL POSTGRAD MED SCH,DEPT HEMATOL,LONDON W12 0HS,ENGLAND
[5] ROYAL POSTGRAD MED SCH,DEPT CHEM PATHOL,LONDON W12 0HS,ENGLAND
[6] PURDUE UNIV,DEPT BIOCHEM,W LAFAYETTE,IN 47907
[7] HARVARD UNIV,SCH MED,DEPT ANAT & CELLULAR BIOL,BOSTON,MA 02115