fibrin and Phlebitis

One (MA-1C8) of 36 monoclonal antibodies obtained by fusion of P3X63-Ag8-6.5.3 myeloma cells with spleen cells of mice immunized with purified human tissue-type plasminogen activator (t-PA) blocked the activity of t-PA on fibrin plates but not on chromogenic substrates. MA-1C8 at a concentration of 200 micrograms/mL inhibited plasma clot lysis and binding of t-PA to the clot. MA-1C8 had no influence on the activation of plasminogen by t-PA, which obeys Michaelis-Menten kinetics with Km = 105 mumol/L and kcat = 0.05 s-1; however, it abolished the influence of CNBr-digested fibrinogen on Km. These findings confirm that the stimulatory effect of fibrin on the activation of plasminogen by t-PA is mediated by binding of t-PA to fibrin and provide additional support for the kinetic model. Addition of t-PA to pooled fresh human plasma to a concentration of 5 micrograms/mL resulted in extensive fibrinogen breakdown after incubation for one hour at 37 degrees C or during storage at -20 degrees C for one day. In both instances, fibrinogen degradation was completely prevented by addition of MA-1C8 to a concentration of 200 micrograms/mL of plasma. MA-1C8 also effectively prevented in vitro fibrinogen degradation and in vitro plasminogen activation in plasma samples obtained during infusion of recombinant t-PA in patients with thromboembolic disease. Thus, MA-1C8 is a useful tool for discriminating between in vivo and in vitro fibrinolysis during thrombolytic therapy with t-PA.

Topics: Animals; Antibodies, Monoclonal; Cyanogen Bromide; Fibrin; Fibrin Fibrinogen Degradation Products; Fibrinogen; Fibrinolysis; Fibrinolytic Agents; Humans; Kinetics; Mice; Mice, Inbred BALB C; Peptide Fragments; Phlebitis; Tissue Plasminogen Activator

Concentrations of plasma fibrinopeptide A (FPA) were measured by radioimmunoassay in 50 patients with venous thromboembolism or disseminated intravascular coagulation or both. A consistent discrepancy was observed in values obtained with two anti-FPA antisera. Analysis of extracts from plasma of these patients by high-performance liquid chromatography (HPLC) revealed the presence of a phosphorylated and an unphosphorylated form of the A peptide. Differences in concentrations of FPA measured with the two antisera could be accounted for by their different reactivity with phosphorylated FPA (FPA-P). The differences were abolished by treatment with alkaline phosphatase. A good correlation was observed between the FPA-P content of free A-peptide material and of fibrinogen in plasma as determined by HPLC (r = .88, P less than .001, n = 11). In patients with elevated FPA levels, the mean FPA-P content of fibrinogen was significantly higher (P less than .002, n = 13) than in patients with normal FPA levels (n = 8) and in healthy controls (n = 14). Phosphorus in fibrinogen did not correlate with fibrinogen degradation products or fibrinogen levels and became normal on adequate anticoagulation. Therefore, blood-clotting activation may lead to a high phosphate content of fibrinogen and of free FPA in plasma.

Topics: Adult; Aged; Chromatography, High Pressure Liquid; Disseminated Intravascular Coagulation; Female; Fibrin; Fibrinogen; Fibrinopeptide A; Heparin; Humans; Male; Middle Aged; Phlebitis; Phosphates

Topics: Abortion, Septic; Blood Coagulation Disorders; Disseminated Intravascular Coagulation; Ethanol; Female; Fibrin; Hematoma; Humans; Leukemia; Liver Cirrhosis; Methods; Neoplasms; Phlebitis; Postpartum Hemorrhage; Pregnancy; Pregnancy Complications, Hematologic; Sepsis

Topics: Adolescent; Adult; Aged; Antigens; Antithrombins; Blood Cell Count; Blood Coagulation; Blood Coagulation Tests; Blood Platelets; Child; Child, Preschool; Factor V; Factor VIII; Female; Fibrin; Fibrinogen; Hemiplegia; Humans; Immune Sera; Immunodiffusion; Male; Middle Aged; Nephrotic Syndrome; Phlebitis; Pulmonary Artery; Renal Veins; Thrombophlebitis; Thrombosis

Topics: Blood Coagulation Tests; Fibrin; Fibrinolysin; Humans; Phlebitis; Time Factors