The flow-independent (intrinsic) tensile modulus of the extracellular matrix of human knee joint cartilage has been measured for normal, fibrillated, and osteoarthritic (removed from total knee joint replacements) cartilage. The modulus was determined in our isometric tensile apparatus and measured at equilibrium. We found a linear equilibrium stress-strain behavior up to approximately 15% strain. The modulus was measured for tissues from the high and low weight-bearing areas of the joint surfaces, the medial femoral condyle and lateral patello femoral groove, and from different zones (surface, subsurface, middle, and middle-deep) within the tissue. For all specimens, the intrinsic tensile modulus was always less than 30 MPa. Tissues from low weight-bearing areas (LWA) are stiffer than those from high weight-bearing areas (HWA). The tensile modulus of the ECM correlates strongly with the collagen/proteoglycan ratio; it is higher for LWA than for HWA. Osteoarthritic cartilage from total knee replacement procedures has a tensile stiffness less than 2 MPa.

Objective. To measure serum levels of tumor necrosis factor a (TNFa) and interleukin-6 (IL-6) in patients with rheumatoid arthritis (RA) and agematched control subjects and to study how these correlate with serum levels of hyaluronan (HA) and antigenic keratan sulfate (KS) and other biochemical as well as clinical indicators of disease activity.Methods. Immunoassays were used to measure levels of TNFa, IL-6, HA, and antigenic KS in the serum of 35 patients with RA and a group of age-and sex-matched control subjects. Clinical disease activity in the RA group was assessed using the Lansbury index. Drug intake was recorded and the erythrocyte sedimentation rate, and levels of fibrinogen, creatinine, biliru-_ _ From the ICP, Connective Tissue Group, and the Department

Objective. To evaluate the effects of the antiresorptive agent alendronate at a daily oral dose of 40 mg in patients with posttraumatic complex regional pain syndrome type I (CRPS I) of the lower extremity.Methods. Forty patients were enrolled in this 8-week randomized, double-blind, placebo-controlled study of alendronate therapy for CRPS I, a condition associated with regional osteoclastic overactivity. An