Comparison of the expression levels of candidate genes in normal and osteoarthritic cartilage. Real time PCR analysis of candidate gene expression in globally amplified cDNA representative of mRNA levels from normal (n = 8) or osteoarthritic (n = 15) human articular cartilage samples. Cartilage for the analysis was derived from either the medial or lateral femoral condyles. NM = normal medial, NL = normal lateral, OM = osteoarthritic medial and OL = osteoarthritic lateral. Symbols above bars indicate statistically significant regulation of that gene caused by:* disease (P < 0.05 mixed effects regression model) or ◆ joint location (P < 0.05 mixed effects regression model).