- Synergistic effect of IGF-1 and OP-1 on matrix formation by normal and OA chondrocytes cultured in alginate beads. Chubinskaya, S., Hakimiyan, A., Pacione, C., Yanke, A., Rappoport, L., Aigner, T., Rueger, D.C., Loeser, R.F. Osteoarthr. Cartil. (2007)