1. College of Medicine, University of Illinois Urbana-Champagne, Urbana-Champagne, Illinois.
2. Department of Biology, University of California, San Diego, San Diego, California.
3. Department of Medicine, University of California, San Diego, San Diego, California.
4. Department of Anesthesiology, University of California, San Diego, San Diego, California.
5. VA San Diego Healthcare System, San Diego, California.