Figure 1

Histological images from lungs of papain- and saline-treated hamsters. (A) control + saline (CS): animals treated with approximately 0.3 mL of saline only; (B) emphysema 20 mg/mL (E20): animals treated with approximately 0.3 mL of 20 mg/mL papain in saline; and (C) emphysema 40 mg/mL (E40): animals treated with approximately 0.3 mL of 40 mg/mL papain in saline. Animals were euthanized after 60 days. Hematoxylin and eosin (H & E) images are shown at 50× magnification. Alveolar destruction was determined by the number of times that a predetermined group of coherent lines (1.25 mm² of total area and 1.50 mm of total length) crossed the parenchymal structures. The lesser these structures are crossed, the more extensive is the lesion.