1. Neuropathology Laboratory, The Johns Hopkins University School of Medicine, Baltimore, MD 21205-2181.
2. Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205-2181.
3. Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205-2181.
4. Center for Molecular Biology, University of Heidelberg, Heidelberg, Federal Republic of Germany.
5. Molecular Therapeutics, West Haven, CT 06516.
6. Department of Neuroscience , The Johns Hopkins University School of Medicine, Baltimore, MD 21205-2181