1. From the Departments of Pathology (Drs Eberhart and Troncoso, and Mr Frazier) and Neurology (Dr Troncoso), Johns Hopkins University School of Medicine, Baltimore, Md; the Department of Neuropathology, Armed Forces Institute of Pathology, Bethesda, Md (Dr Morrison); the Department of Pathology, University of Maryland, School of Medicine, Baltimore (Drs Gyure and Smialek); and the Office of the Chi