Increased concentration of two different advanced glycation end-products detected by enzyme immunoassays with new monoclonal antibodies in sera of patients with rheumatoid arthritis.

Background: Levels of pentosidine (representative of advanced glycation end-products) in sera of patients with rheumatoid arthritis are increased when compared with sera of other diagnoses or healthy controls. These levels have been reported to correlate with clinical indices of rheumatoid arthritis activity and with laboratory markers of inflammation. The purpose of this study was to find out if these findings pertain to other advanced glycation end-products.

Ascorbic acid increases the severity of spontaneous knee osteoarthritis in a guinea pig model.

Objective: To determine whether ascorbic acid might be of benefit for the treatment of spontaneous osteoarthritis (OA) when administered over a long period of time.

Methods: We investigated the effects of 8 months' exposure to low, medium, and high doses of ascorbic acid on the in vivo development of histologic knee OA in the male Hartley guinea pig. The low dose represented the minimum amount needed to prevent scurvy.

Ethnic and sex differences in serum levels of cartilage oligomeric matrix protein: the Johnston County Osteoarthritis Project.

Objective: Previous descriptions of potential biomarkers of osteoarthritis (OA) have been limited to Caucasians. In the present study, we examined associations between serum levels of cartilage oligomeric matrix protein (COMP) and ethnicity (African American or Caucasian) and sex in the Johnston County Osteoarthritis Project, a population-based study of OA in rural North Carolina.

Methods: All African Americans and a randomly selected sample of Caucasians who had available sera and either no radiographic evidence of knee or hip OA according to the Kellgren/Lawrence (K/L) system (K/L grade 0) or radiographic evidence of knee OA (K/L grade 2 or higher) were included.

Monoclonal antibodies to human cartilage oligomeric matrix protein: epitope mapping and characterization of sandwich ELISA.

Background: Cartilage oligomeric matrix protein/thrombospondin 5 (COMP/TSP 5) is one of the most promising serologic markers with regard to an ability to prognose development of osteoarthritis (OA). Our aim was to map the epitopes of three monoclonal antibodies (mAb) to COMP and to develop and characterize a sandwich enzyme-linked immunosorbent assay (ELISA) for measuring COMP levels in human body fluids.

Methods: COMP was digested with trypsin and the NH(2)-terminal sequence of the fragments recognized by each of the mAbs was determined.

Concentrations of cartilage oligomeric matrix protein in dogs with naturally developing and experimentally induced arthropathy.

Objective: To assay concentrations of cartilage oligomeric matrix protein (COMP) in canine sera and synovial fluid (SF), to compare COMP concentrations in clinically normal dogs and dogs with joint disease, and to analyze changes in COMP concentrations in dogs with experimentally induced acute synovitis.

Animals: 69 control dogs without joint disease, 23 dogs with naturally occurring aseptic arthropathy, and 6 dogs with experimentally induced synovitis.

Procedure: Serum (n = 69) and SF (36) were obtained from control dogs.