To whom reprint requests should be addressed at: Massachusetts Institute of Technology E25-342, 45 Carleton Street, Cambridge, MA 02139. e-mail: Lfreed@mit.edu .
A commentary on this article begins on page 13380.
We are grateful to A.J. Grodzinsky, who provided the expertise and facility needed to measure construct mechanical properties; F.J. Schoen, who prepared and, with A.J. Grodzinsky, helped interpret the transmission electron micrography; A.P. Hollander, who developed and performed the quantitative collagen type II assay; S. Eisenberg, S. Kleis, B. Obradovic, and D. Stamenovic for many stimulating discussions; Z. Antonijevic, who helped with the statistical analysis; and J. Barry, R. Padera, H. Shing, and S. Treppo for their technical assistance. This study could not have been accomplished without the dedicated efforts of J. Blaha (Mir), and D. Brown, M. Casteel, J. Craig, R. Garcia, S. Gonda, T. Goodwin, L. McClarty, T. Trinh, J. Washington, and M. Young (Johnson Space Center). The funding for this work was provided by the National Aeronautics and Space Administration Microgravity Research Division and Grant NAG9-836 with additional support from Advanced Tissue Sciences.
GAG, glycosaminoglycan; PGA, polyglycolic acid; BTS, Biotechnology System (bioreactor).