1. Department of Surgery and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
2. Pittsburgh Trauma Research Center, Pittsburgh, Pennsylvania
3. Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania
4. Department of Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
5. Department of Surgery, University of Tennessee Health Science Center, Knoxville
6. Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee
7. Department of Surgery, University of Louisville, Louisville, Kentucky
8. MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio
9. Department of Surgery, University of Texas Southwestern, Dallas
10. Department of Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania