[1] Yale Univ, Sch Med, Dept Neurol, New Haven, CT 06510 USA
[2] Univ Washington, Harborview Med Ctr, Dept Neurol, Med Ctr, Seattle, WA 98104 USA
[3] Univ Calif San Francisco, Dept Neurol, San Francisco, CA USA
[4] Univ N Carolina, Dept Neurol, Chapel Hill, NC USA
[5] Med Univ Innsbruck, Bioctr, Div Biol Chem, A-6020 Innsbruck, Austria