Tissue Factor Coagulant Activity Research Articles

Monocyte tissue factor activity in anticoagulant-treated patients

The tissue factor coagulant activity of peripheral blood monocytes was measured in 20 patients on long-term anticoagulant treatment with warfarin and in 21 healthy individuals. Contrary to expectations, tissue factor activity was not reduced in the warfarin-treated group and was, in fact, elevated in several patients. No relationship existed between the daily warfarin dose or the degree of prolongation of the prothrombin time and the monocyte tissue factor activity. These results indicate that monocyte tissue factor activity is not necessarily reduced to below normal levels with warfarin treatment.

Binding of bovine brain tissue factor to concanavalin asepharose. Partial purification of coagulant, arylamidase, and alkaline phosphatase activities

Tissue factor coagulant activity is adsorbed onto concanavalin A-Sepharose from sodium deoxycholate extracts of delipidated bovine brain powders. Coagulant activity is eluted with α-methyl- d-glucoside in sodium deoxycholate with 2–25-fold purification. This material has the same coagulant specific activity as that previously prepared in this laboratory. Alkaline phosphatase and alanyl-β-naphthylamidase activities in the detergent extract also bind to concanavalin A-Sepharose and elute under the same conditions with 4- and 7-fold purification. In addition to these biological activities, the elute was composed of protein (67.7%), neutral and amino sugars and sialic acid (22.3%), phospholipid (4.5%), uronic acid (3.8%) and nucleic acid (1.7%). This preparation is slightly enriched in carbohydrates compared to previous preparations. Concanavalin A-Sepharose therefore appears to be useful material for partial purification of several mammalian plasma membrane components with retention of biological function.

Concanavalin A inhibits tissue factor coagulant activity.

Concanavalin A (con A) is a potent inhibitor of coagulant activity of native tissue factor. Coagulant activity is recovered by addition of alpha-methyl-D-glucoside to inhibited tissue factor. Inclusion of alpha-methyl-D-glucose during incubation of con A with tissue factor preserves coagulant activity. These data suggest that con A interacts reversibly with a carbohydrate residue in such a way as to inhibit coagulant activity of the molecule. Purified tissue factor apoprotein has been recombined with mixed brain phospholipids or purified phospholipids (phosphatidyl ethanolamine or a mixture of phosphatidyl choline with phosphatidyl serine). These preparations were also completely but reversibly inhibited by con A. Thus, purified tissue factor apoprotein appears to donate the affected carbohydrate residue.