Subjects will then be discharged to home with contact information for study staff. If a volunteer has an unexpected complication such as shortness of breath, decrease in pulmonary function, unstable vital signs or other he or she will be admitted to the GCRC for overnight observation. The next morning (study day 3) subjects will return to the CEMALB for a final set of vital signs, spirometry, symptom scoring, a venipuncture and an examination by a study physician.