[1] HOSP PRINCIPES ESPANA,SERV ANAT PATOL,UNIDAD NEUROPATOL,E-08907 LHOSPITALET LLOBR,SPAIN
[2] HOSP PRINCIPES ESPANA,SERV GASTROENTEROL,LHOSPITALET LLOBR,SPAIN
[3] HOSP CLIN BARCELONA,SERV NEUROL,E-08036 BARCELONA,SPAIN
[4] MEM SLOAN KETTERING CANC CTR,DEPT NEUROL,NEW YORK,NY 10021