Fig. 3.

Quantitation of the osteogenic activity. BLK cells were transduced with AdCMV-BMP7 and implanted into C57BL/6 mice as described in figure 2. Osteogenesis by implants was assessed by homogenizing ossicles in 15% trichloroacetic acid and measuring total calcium in supernatants. a Effect of cell number. BLK cells were transduced at an m.o.i. of 100 and the indicated numbers of cells were implanted. Osteogenesis was assessed after 3 weeks. b Time course. BLK cells (1 × 10⁷ cells/implant) were transduced at an m.o.i. of 100, implanted and harvested at the times indicated. c, d Effect of virus titer. BLK cells were transduced with the indicated virus titers. One set of cells was implanted and harvested after 3 weeks for measurement of bone formation (c) and a second set was incubated in serum-free medium for 24 h for measurement of BMP7 secretion by Western blotting (d).