FIG. 6.

Histopathology of lungs 48 h after infection of mice with 3.5 × 10⁷ CFU of S. pneumoniae and treatment with placebo (A and C) or L-NMMA (B and D), 3 mg/kg given every 12 h since initial infection. Better preservation of interstitium and alveolar structures was noted after treatment with L-NMMA, as alveoli were kept open and edema was reduced, compared to those in untreated lungs. Magnifications, ×45 (A and B) and ×375 (C and D).