One day old mice were injected retro-orbitally with rAd-lacZ (2 × 109 particles/gram), as described in methods. Subsequently, they were sacrificed at different time points post injection. Tissue samples were harvested and examined for β-gal expression by X-Gal staining (blue color). The panels show representative pictures demonstrating blue β-gal staining in: (A) heart, 7 days after injection; (B) lung, 7 days after injection., (C) intestine, 7 days after injection; (D) heart, 360 days after injection; (E) lung, 90 days after injection; and (F) intestine, 90 days after injection. Bar graph: 500 µm.