Figure 1.

Distribution of α SMA-immunoreactivity in pulmonary veins. (A) Course of a pulmonary vein from the proximal cardiac muscle covered part (upper left) to the pleural surface (arrows). (B) Magnification of the vessel shown in upper boxed area in A. α SMA-immunoreactive cells are branched and build a loose mesh. (C) Magnification of the vessel shown in lower boxed area in A. Few immunoreactive cells are present in the distal part of the vein. α SMA-immunoreactive cells are predominantly located close to the branch point (arrows). (D) A singular, branched α SMA-immunoreactive cell in a distal intra-acinar vein. (D') Differential interference contrast image of D. Bars in A, B, C = 100 μm; in D, D' = 50 μm.