Pulmonary EmphysemaEmphysemaSubcutaneous EmphysemaPancreatic Elastasealpha 1-Antitrypsin DeficiencyMediastinal Emphysemaalpha 1-AntitrypsinLungMatrix Metalloproteinase 12Pulmonary AlveoliRespiratory Function TestsSmokeHeliumPulmonary Disease, Chronic ObstructivePneumonectomySmokingTomography, X-Ray ComputedElastinForced Expiratory VolumeVasculitis, Leukocytoclastic, CutaneousPanniculitisBronchoalveolar Lavage FluidPulmonary FibrosisLung CompliancePneumoniaLung DiseasesDisease Models, AnimalBronchiMice, Inbred C57BLTobaccoTotal Lung CapacitySeverity of Illness Index