Figure 2. Effect of SMF on mineralized bone nodule formation in rat calvaria cell cultures. Photograph of wells after von Kossa staining (A), time-course of total area (B), number of bone-like nodules (C), and calcium content in the cell matrices (D). Filled circles, exposed to SMF; open circles, non-exposed controls. Data are presented as mean ± SD (n = 4). Asterisks show a significant difference from control values at *P < 0.05 and **P < 0.01, by Student’s t test.