1. From the Section of Neurosurgery (R.S., C.S., C.A., T.M., R.L., Y.C., L.Z., M.W., H.A.Z., R.G., I.A.A.), Department of Pathology (P.P.), Section of Cardiology (J.K.L.), Biological Sciences Division, University of Chicago, IL; and the Molecular Genetics and Microbiology Department, Duke University Medical Center, Durham, NC (D.A. McDonald, A.R., C.G., D.A. Marchuk).