1. Department of Medicine, Division of Hematology, Little Rock Veterans Administration Hospital, Little Fock, Ark. 72206; the Department of Medicine, Division of Pulmonary Diseases, Ohio State University, Columbus, Ohio 43210; and the Department of Medicine, The George Washington University Medical Center, Washington, D.C. 20037.
2. Hematology Division, Department of Medicine, Little Rock Veterans Administration Hospital, Little Rock, Ark. 72206.
3. Division of Pulmonary Diseases, Department of Medicine, Ohio State University, Columbus, Ohio 43210
4. Department of Medicine, The George Washington University Medical Center, Washington, D.C. 20037.