1. Division of Pulmonary and Critical Care Medicine, Hines Veterans Affairs Hospital, Hines, Illinois
2. Loyola University of Chicago Stritch School of Medicine, Maywood, Illinois
3. RML Specialty Hospital, Hinsdale, Illinois
4. University at Buffalo, Buffalo, New York
5. University of Illinois at Chicago, Chicago, Illinois
6. University of Wisconsin, Madison, Wisconsin; and
7. University of Pittsburgh, Pittsburgh, Pennsylvania