Relative expression levels of the messages for hyaluronan synthase-1, -2, and -3 and hyaluronidase-1, -2, and -3 in the synovium of knees in osteoarthritis (OA) and rheumatoid arthritis (RA). Total RNA was isolated from knee synovium and expression levels of the messages were relatively quantified by real-time reverse transcriptase polymerase chain reaction. The expression levels of the messages in OA and RA are expressed by longitudinal bars relative to those of the control value expressed as 1.0. The lines outside the bars represent the standard deviation of the change in threshold cycle numbers (ΔCT) corrected with CT values of β-actin message used as an internal standard. * P < 0.01.