Serum concentration of keratan sulfate. Blood was collected every week at 0 to 5 weeks. Sequential serum concentrations of keratan sulfate are shown individually in the control group (left panel) and in the hyaluronan group (center panel). Maximum values of the concentrations are plotted, and the average values are shown in the right panel (control, n = 8; injection of hyaluronan, n = 5). **P < 0.05 by Mann–Whitney U test.
Tang et al. Arthritis Research & Therapy 2008 10:R13 doi:10.1186/ar2363