Background: Diagnosis of osteonecrosis of the femoral head (ONFH) is complicated due to the lack of reliable serum biomarkers. Up-regulation of alpha-2-macroglobulin (A2M) gene has been reported in glucocorticoid-induced ANFH rat model. This study aimed to investigate whether the serum level of alpha-2-macroglobulin (A2M) can be used for ONFH diagnosis. Methods: Serum protein capillary elect...

Plasma values of C reactive protein, alpha 1 proteinase inhibitor, alpha 2 macroglobulin, and complexed alpha 2 macroglobulin have been determined in serial samples from 27 patients with acute pancreatitis. Complexed alpha 2 macroglobulin was measured by a novel enzyme linked immunosorbent assay with a monoclonal antibody specific for the complexed form. Patients with severe illness had lower c...

The alpha-2 macroglobulins from human serum and plasma were isolated by Bio-Gel P-300 and A5m gel filtration. The material showed a single peak on sedimentation velocity ultracentrifugation, a mol wt of 650,000 by sedimentation equilibrium ultracentrifugation, and a major precipitin arc in the alpha-2 macroglobulin region by immunoelectrophoresis against whole human serum. Two bands were observ...

Alpha-2-macroglobulin is an abundant secreted protein that is of particular interest because of its diverse ligand binding profile and multifunctional nature, which includes roles as a protease inhibitor and as a molecular chaperone. The activities of alpha-2-macroglobulin are typically dependent on whether its conformation is native or transformed (i.e. adopts a more compact conformation after...

We studied the synthesis and secretion of alpha-2-macroglobulin by cultures of human adherent cells. Much more alpha-2-macroglobulin (measured by radioimmunoassay) accumulated in media of established strains of adherent cells derived from embryonic lung than in media of established strains derived from adult skin or rheumatoid synovium. Alpha-2-macroglobulin accumulated in media of primary cult...

The proteolytic activity of trypsin releases the dye Remazol Brilliant Blue from its high molecular weight substrate, the skin powder (Hide Powder Azure, Sigma), with an increase in absorbance at 595 nm. Active alpha(2)- macroglobulin (80 mug/ml) totally inhibits the proteolytic activity of trypsin (14 mug/ml) by trapping this protease. But after a 20 min incubation of alpha(2)-macroglobulin at...

Activation of plasma kallikrein arginine esterase activity by kaolin resulted in peak activity at 1 min of incubation and a 50% reduction in activity at 5 min in normal plasma, and 30% reduction in the plasma of patients with hereditary angioneurotic edema who lacked the C1 inactivator. The peak esterolytic activity was inhibited by soybean trypsin inhibitor whereas the 5 min activity was resis...