Bovine articular chondrocytes in micromass culture. Bovine articular chondrocytes grown in micromass cultures were left untreated (A) and (C) or treated with transforming growth factor β (TGF-β) (B) and (D) for 7 days. Cultures were stained for Alcian blue (A) and (B) or alkaline phosphatase (C) and (D). Quantification of staining showed an increase in Alcian blue staining (E) and a decrease in alkaline phosphatase activity after treatment with TGF-β (F). *P-value < 0.05 by t-test. pNP: p-nitophenol.