Fig. 4.

Histological characteristics of buccal and small airway cultures. Representative images of buccal (a) and small airway (b) culture sections stained with hematoxylin and eosin 48 h after exposure to diluted 3R4F cigarette smoke or undiluted test mix, base, or carrier aerosols at the indicated concentrations for 28 min (112 puffs). Small airway cultures were also stained with Alcian blue to visualize goblet cells. Bar = 100 µm. PBS phosphate-buffered saline