Figure 4. Effect of SMF on two markers of osteoblastic phenotype: ALP activity in rat calvaria cells (A), ROS 17/2.8 cells (C), and UMR 106 cells (D); and osteocalcin content in the conditioned media of rat calvaria cell cultures (B). Filled circles and bars, exposed to SMF; open circles and bars, 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.