1. Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, Maryland.
2. Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland.
3. Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland.
4. Department of Surgery, Walter Reed Army Medical Center, Washington, D.C.
5. Department of Surgery, University of Maryland School of Medicine, Baltimore, Maryland.
6. R. Adams Cowley Shock Trauma Center, Baltimore, Maryland.