Figure 1. Western blot films and immunohistochemical micrographs demonstrating the presence of -smooth-muscle actin (SMA) in pulp cells. (a) Western blot films showing the SMA content of freshly isolated pulp cells and cells after passages 1 and 3. The control band from the smooth-muscle cells controls is also shown for each run. The amount of protein used for each run is noted under the band. Less protein was used for the higher passage because the SMA content was so high that it blackened the film. (b-d) Immunohistochemistry of pulp cells in monolayer culture after the first (b) and third (d) passages showing the presence of SMA (darkly stained stress fibers) in many of the cells (b, d). The SMA can be seen incorporated into the prominent stress fibers (d). The negative control sample, absent the primary antibody (c), shows no sign of the chromogen. Scale bar, 50 µm.