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1 Department of Medicine, Oregon Health & Science University, Portland, OR; Providence Portland Medical Center, Portland, OR; Oregon Clinic, Portland, OR. Electronic address: john_heffner@mac.com.
2 Medical University of South Carolina, Charleston, SC.
3 Division of Pulmonary, Allergy & Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL.
1 Department of Medicine, Oregon Health & Science University, Portland, OR; Providence Portland Medical Center, Portland, OR; Oregon Clinic, Portland, OR. Electronic address: john_heffner@mac.com.
2 Medical University of South Carolina, Charleston, SC.
3 Division of Pulmonary, Allergy & Critical Care Medicine, University of Alabama at Birmingham, Birmingham, AL.