1. Department of Pathology, New York University Medical Center, New York, NY 10016.
2. Athena Neurosciences, Inc., South San Francisco, CA 94080.
3. Departrnent of Pathology, University Medical Center Leiden, 2300 R.C. Leiden, the Netherlands.
4. Department of Neurosurgery, University Medical Center Leiden, 2300 R.C. Leiden, the Netherlands.
5. Kaplan Cancer Center, New York University Medical Center, New York, NY 10016.