1. Stroke Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
2. Bristol-Myers Squibb, Princeton, New Jersey
3. Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland
4. Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, Kansas, U.S.A.