1. G. C. Telling and J. Mastrianni, Department of Neurology, University of California, San Francisco, CA 94143, USA.
2. P. Parchi and P. Gambetti, Division of Neuropathology, Department of Pathology, Case Western Reserve University, Cleveland, OH 44106, USA.
3. S. J. DeArmond, Departments of Neurology and Pathology, University of California, San Francisco, CA 94143, USA.
4. P. Cortelli, P. Montagna, E. Lugaresi, Department of Neurology, University of Bologna, Bologna 40123, Italy.
5. R. Gabizon, Department of Neurology, Hadassah Medical Center, Hebrew University, Jerusalem 91120, Israel.
6. S. B. Prusiner, Departments of Neurology and Biochemistry and Biophysics, University of California, San Francisco, CA 94143, USA.