Figure 2.

Native collagen fibrils assemble in human SMC cultures. Electron micrographs of human SMCs, cultured in ascorbate-deficient media, 24 hours after the addition of soluble, bovine skin collagen. Cross-striated collagen fibrils are apparent near the cell surface (a and at higher magnification in inset). Fibrils can also be seen in membrane-delimited cellular invaginations (arrows). b: Collection of fibrils seen in cross-section within a cell-surface depression at a zone of apposition with an adjacent cell. Scale bar, 500 nm (a).