1. Pittsburgh Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, Pennsylvania.
2. Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.
3. Department of Biochemistry, Center for Molecular Medicine, Institute of Biochemistry, Cologne University, Cologne, Germany.
4. Department of Biochemistry, University of California at Riverside, Riverside, California.
5. Department of Anesthesiology, University of Pittsburgh, Pittsburgh, Pennsylvania.
6. Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, Pennsylvania.