1. Department of MedicineDivision of Pulmonary and Critical Care MedicineJesse Brown Veterans Affairs Medical Center ChicagoIllinoisUSA
2. Department of Medicine ChicagoIllinoisUSA
3. Department of Pathology ChicagoIllinoisUSA
4. Facultad de CienciasUniversidad Nacional Autónoma de México México City Mexico
5. Instituto Nacional de Enfermedades Respiratorias Ismael Cosío Villegas México City Mexico
6. Department of Radiation BiologyNorthwestern University Feinberg School of Medicine ChicagoIllinoisUSA