Glucosamine sulfate modulates dysregulated activities of human osteoarthritic chondrocytes in vitro.

Objective: The efficacy of glucosamine sulfate (GS) in the symptomatic treatment of patients with osteoarthritis (OA) is suggested to be mediated by still unknown effects on the altered OA cartilage.

Design: Using human OA chondrocytes in culture, the effects of GS on protein synthesis, caseinase, collagenase, phospholipase A2 (PLA2) and protein kinase C (PKC) activities as well as production of nitric oxide and cyclic AMP were studied in both cells and culture medium.

Results: GS significantly reduced PLA2 activity, and more modestly collagenase activity, in the OA chondrocytes in a dose-dependent manner.

Osteoarthritic cartilage fibrillation is associated with a decrease in chondrocyte adhesion to fibronectin.

Objective: Cartilage destruction in osteoarthritis (OA) is generally accepted as a failed repair process. Cell adhesion is implicated in tissue repair. Therefore, adhesion of OA chondrocytes to extracellular matrix proteins was investigated.

Phospholipase A2 activity in herniated lumbar discs. Clinical correlations and inhibition by piroxicam.

Study Design: Prospective study of phospholipase A2 activity in the serum and intervertebral discs of patients undergoing surgery for sciatica due to disc herniation.

Objectives: To determine correlations between herniated disc phospholipase A2 and clinical, radiographic, and anatomic signs of common sciatica; to evaluate serum phospholipase A2 activity as a marker of disc phospholipase A2; and to investigate the in vivo effect of piroxicam on disc phospholipase A2.

Summary Of Background Data: Several studies suggest disc inflammation as a mechanism of sciatica due to disc herniation, and phospholipase A2 emerges as a key enzyme of cartilage and disc tissues.

Calcitonin inhibits phospholipase A2 and collagenase activity of human osteoarthritic chondrocytes.

Calcitonin (CT) is a known potent inhibitor of bone resorption but its effect on cartilage enzymatic degradation has been incompletely studied. Salmon CT, at a concentration of 0, 0.1, 0.

Effect of non-steroidal anti-inflammatory drugs (NSAIDS) on glycosyltransferase activity from human osteoarthritic cartilage.

The effect of non-steroidal anti-inflammatory drugs (NSAIDs) on the activity of glycosyltransferases required for the synthesis of the polysaccharide chains of proteoglycans, was studied in human osteoarthritic cartilage in vitro. Using exogenous acceptors, salicylate and indomethacin suppressed the activity of glucuronyl- and xylosyltransferases in a concentration-dependent manner, but had little effect on N-acetylgalactosaminyl- and galactosyltransferases. When used at a concentration derived from the values found in the synovial fluid, salicylate, indomethacin and chloroquine significantly suppressed the activity of glucuronyl- and xylosyltransferases, while tiaprofenic acid, paracetamol (acetaminophen), floctafenine, ketoprofen, ibuprofen and tenoxicam had no effect on the enzymes.