SummaryAn enzyme-linked immunosorbent assay (ELISA) was developed for the determination of thrombin-antithrombin III complex (TAT) in human plasma. The test system follows the sandwich principle and uses two different antibodies directed against human thrombin and human antithrombin III, respectively. The antibodies bind selectively to the corresponding antigen moieties of TAT. The assay was calibrated with definite concentrations of preformed purified TAT added to TAT-poor plasma. The lower limit of sensitivity of the assay was 0.5 μg/1. Mean coefficients of variation of 4.2% (intraassay) and 3.5% (interassay) were found for TAT concentrations between 2 and 60 μg/1. A reference range from 0.85 to 3.2 μg/1 was calculated from TAT concentration in plasma samples from 88 healthy donors (mean value ± SD: 1.45 ± 0.4 μg/I). In plasma samples from patients with pulmonary embolism (n = 17), TAT concentrations between 3 and 25 μg/1 were measured. In 15 patients with deep vein thrombosis, TAT was found up to 3 to 25 μg/1. From these data we conclude that measurement of TAT can be a sensitive parameter for specific detection of a latent activation of the clotting pathway.
Homozygous type I plasminogen (Plg) deficiency has not been described in human subjects so far. Ligneous conjunctivitis is a rare and unusual form of chronic pseudomembranous conjunctivitis of unknown etiology. Here we report for the first time on homozygous type I Plg deficiency in three unrelated female patients who suffered from ligneous conjunctivitis and additional pseudomembranous lesions of other mucous membranes. The disease is caused by massive fibrin depositions within the "extravascular space" of mucous membranes because of absent clearance by plasmin. Infusions of albumin, fresh frozen plasma, or Lys-plasminogen (Lys-Plg) into two of the three patients revealed normal Plg activation capacity in these patients. The absence of fibrinolytic activity could therefore be shown to be due to Plg deficiency. Similar studies in the third patient have not been completed. In the two patients studied so far, infusions of Lys-Plg resulted in prompt and adequate Plg recovery with a short half-life and high amounts of plasmin-antiplasmin complexes and D-dimer. One patient additionally revealed an inherited partial factor XII deficiency. Functionally, this factor XII deficiency did not interfere with Plg activation. However, there may be a pathway of Plg activation in this patient via the prekallikrein C1-INH system.
A simple procedure for the isolation of CI-Inactivator from fresh human ACD plasma is described consisting of the following fractionation steps : DEAE chromatography, ammonium sulfate precipitation, Sephadex G-I50 gel filtration and zone electrophoresis. A 250-fold concentration was achieved in good agreement with an immunologically determined Ci-Inactivator concentration of 25 mg/lOO ml serum.Ci-Inactivator is a glycoprotein containing 35O/, carbohydrates ; it migrates with the a,-globulins a t pH 8.6 and in the PS-1 zone a t pH 4.4. The isoelectric point is between 2.7-2. Ziel dieser Arbeit war es, einerseits ein Verfahren fur die halbtechnische Herstellung von Ci-Inaktivator zu entwickeln und andererseits den Inhibitor biologisch und physikalisch-chemisch naher zu charakterisieren.
Human protein C-inhibitor (PCI) was isolated from human citrated plasma by combining rivanol precipitation, ammonium sulfate precipitation, ion-exchange chromatography on DEAE-Sephacel and affinity chromatography on dextran sulfate Sepharose. The purified PCI migrated with the ß-globulins and was free from protein contaminations as judged by immunoelectrophoresis. In SDS-PAGE under reducing and unreducing conditions PCI showed a single band at M t = 57 000. The specific activity of the inhibitor was 226 units/mg. Surprisingly, the isolated PCI inhibited the amidolytic activity of urokinase (u-PA) on '-olu-Gly--Arg-pNA (S-2444) in a time-dependent manner. Heparin, dextran sulfate and pentosanpolysulfate accelerated the reaction catalytically. PCI revealed itself as a non-competitive inhibitor of u-PA. The Rvalue was determined to be 7.9 10~8M. Inhibition of amidolytic activity was found to be associated with the formation of an 1:1 equimolar complex with a M r of 110 000 as demonstrated by means of polyacrylamide gel electrophoresis and following Western blotting technique using polyclonal antibodies against u-PA and PCI. The specific activity of the isolated PCI of 226 units/mg, which approximates the theoretical value of pure PCI, indicates a highly purified preparation of PCI. The heparin-dependent inhibition of urokinase by this highly purified protein as well as comparison of the kinetic data and amino-acid composition of both PCI and the recently described plasminogen activator inhibitor (PAI) 3 give high evidence of identity of PCI and PAI-3.
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