Histidine-rich glycoprotein during pregnancy.
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Blood Proteins↗
Biomedical subjects
F Bachmann
Publications and source records attributed to F Bachmann.
Determination of intermediates, products and cleavage site in the reaction between plasminogen activator inhibitor type-2 and urokinases.
Several specific inhibitors for plasminogen activators have been isolated from various organs and cell lines, those from human placenta and the human monocyte-like cell line U-937 being virtually identical. The reaction between this type of inhibitor, designated as type-2, and high-Mr and low-Mr urokinase-type plasminogen activators was followed by reversed-phase high-performance liquid chromatography and gel electrophoresis. The components, their stable complexes and their dissociation and cleavage products could be clearly identified in both systems. The amino acid sequence of the inhibitor at the cleavage site was determined to be -Met-Thr-Gly-Arg decreases Thr-Gly-His-Gly-. A 35-residue carboxy-terminal fragment was found to be released.
Amino Acid Sequence↗
Plasminogen activator inhibitor 1 and plasminogen activator inhibitor 2 in various disease states.
The association of increased PA-inhibitor (PAI) activity and of PAI-1 and PAI-2 antigen levels with different pathological conditions was studied in a collective of over 300 patients. PAI-1 and PAI-2 levels were measured by specific radioimmunoassays. A good correlation was observed of PAI activity with PAI-1 antigen (r = 0.718; p less than 0.0001) but not with PAI-2 (r = 0.070; n.s.). Both in the controls and in the patients, PAI activity and PAI-1 antigen showed an extremely large range of values. PAI activity ranged from 0.5 to 68 U/ml and PAI-1 antigen from 6 to 600 ng/ml. Increased PAI activity and PAI-1 antigen was observed in patients with malignant tumors, cardiovascular or thromboembolic disease, in the postoperative phase, with hepatic insufficiency, after trauma and after extracorporeal circulation. The large spectrum of disease states with increased PAI activity and PAI-1 antigen reinforces previous suggestions that PAI-1 is an acute phase reactant. After extracorporeal circulation, PAI activity and PAI-1 concentrations strongly increased within one hour, remained elevated for at least one week and returned to preoperation values within 7 days. PAI-2 values ranged from below detection limit (15 ng/ml), observed in half of the plasmas, to 485 ng/ml in a pregnant woman. High values of PAI-2 were only observed in pregnancy.
Glycoproteins↗
[Differentiation of a normal population and of a cohort of patients presenting with a history of idiopathic thromboembolism as identified with fibrinolytic tests].
To identify persons at risk for development of thromboembolic disease, fibrinolytic and blood coagulation parameters of normal controls (n = 40) and patients (n = 40) have been compared. Four fibrinolytic parameters, i.e. fibrinolytic activity at rest (FAr), fibrinolytic response after 10 minutes of venous occlusion (delta FA10'), and resting antigenic levels of the plasmatic inhibitor of the plasminogen activators (PAI-1) and of urokinase (u-PA), showed significant differences between the two study groups. The separate and combined discriminant analysis of FAr and delta FA10' values revealed that individuals with FAr below 0.63 UI/ml or a delta FA10' below 0.98 UI/ml are at risk for development of thromboembolic disease.
Adult↗
Adjusted subcutaneous heparin versus heparin plus dihydroergotamine in prevention of deep vein thrombosis after total hip arthroplasty.
In a prospective randomized study, two different antithrombotic regimens were compared with regard to their effects on the incidence of deep vein thrombosis (DVT) in 102 patients undergoing elective total hip arthroplasty. Fifty patients (group 1) received heparin subcutaneously three times daily in doses adjusted as a function of activated partial thromboplastin time (APTT), and 52 patients (group 2) received a fixed dose of 5,000 IU heparin plus 0.5 mg dihydroergotamine twice daily. Both treatments were started 2 days before operation and continued for 7-9 days after operation, when venography of the operated leg was performed in all patients. The overall incidence of DVT was 22% in group 1 and 19.6% in group 2. Eight patients (16%) in group 1 and four (7.6%) in group 2 developed proximal DVT. These differences were not statistically significant. Hemorrhagic complications occurred more frequently in group 1. Heparin plus dihydroergotamine is a simple and effective method of preventing DVT in patients undergoing total hip arthroplasty. Daily APTT-adjusted subcutaneous heparin remains the best method of prevention of DVT in patients with contraindications to the use of dihydroergotamine and those with two or more DVT risk factors.
Dihydroergotamine↗
[Structure, function and use of fibrinolysis-promoting and inhibiting factors].
Our knowledge about the components of the fibrinolytic system has greatly increased during the last few years thanks to the cloning of the cDNA of the two plasminogen activators t-PA and u-PA, of the two plasminogen activator inhibitors PAI-1 and 2, and of other profibrinolytic and of inhibitory factors of this system. The two principal plasminogen activators (PA) and the two PA-inhibitors are present in infinitesimal concentrations in blood (pM to microM range) and in tissues. The expression of the t-PA and of the u-PA cDNA in mammalian cells and in E. coli bacteria has rendered it possible to produce sufficient amounts of these thrombolytic disorders for clinical studies. Over 2000 patients afflicted with acute myocardial infarction have been treated so far with recombinant t-PA. In general, the thrombolytic effect of t-PA appears to be superior to that obtained with streptokinase and the fibrin-specific-PA produces lesser fibrinogenolysis than the first generation thrombolytic agents streptokinase and two-chain urokinase.
Chemical Phenomena↗
Monoclonal antibodies directed against human tissue-type plasminogen activator: a characterization of their species specificity, affinity and heavy-chain binding.
Six monoclonal antibodies (mIgG) and a polyclonal antibody (pIgG) directed against human tissue-type plasminogen activator (t-PA) were tested for their species specificity towards human or murine t-PA. Whereas pIgG as well as several mIgGs discriminated poorly between these two t-PA species, one mIgG (clone E3) was highly specific for human t-PA. Inhibition and binding studies of human t-PA by mIgGs revealed high affinity-high inhibitory (E3) as well as high affinity-poor inhibitory (B1) mIgGs. The relative affinity of two mIgGs for human t-PA was found to be equal or even superior to that of pIgG. Immunoblotting of reduced two-chain t-PA and of an isolated heavy chain of t-PA prepared by recombinant DNA technology, showed that the E3 antibody was directed against the heavy chain of t-PA.
Animals↗
Histopathology of myelodysplastic syndromes. The FAB classification (proposals) applied to bone marrow biopsy.
Twenty-eight cases of myelodysplastic syndrome (MDS) were reviewed to evaluate whether the morphologic criteria proposed by the French-American-British (FAB) Cooperative Group for marrow smears could be applied to glycol methacrylate embedded trephine biopsies. Bone marrow biopsies and marrow smears were examined separately and then compared for the following parameters: percentage of blasts, dyserythropoiesis, ring sideroblasts, dysmegakaryopoiesis, dysgranulopoiesis, monocytes, cellularity, fibrosis, and "abnormal localization of immature precursors". The results of the histologic (biopsies) and cytologic (marrow smears) examinations were in good agreement in 24 of 28 cases. The authors' results suggest that the five MDS types proposed by the FAB group can be reliably distinguished on bone marrow biopsy with knowledge of the peripheral blood blast and monocyte counts. When the bone marrow aspiration is inadequate, the biopsy can establish diagnosis and type of MDS and rules out aplasia or tumor infiltration as possible alternative causes of cytopenia.
Adult↗
Anisoylated plasminogen streptokinase activator complex versus streptokinase in acute myocardial infarction. Preliminary results of a randomised study.
25 patients with acute myocardial infarction pain lasting more than 20 minutes which was not relieved by nitrates, whose ECGs showed ST segment elevations of 1 mm or more in 2 or more ECG leads, and who presented less than 3 hours after onset of their symptoms were randomly assigned to one of 2 thrombolytic treatment groups: a single intravenous bolus of anisoylated plasminogen streptokinase activator complex (APSAC) 30U in 5 minutes or an intravenous infusion of streptokinase 1,500,000U over 60 minutes. 3 to 4 hours after the administration of the thrombolytic agent, all patients received intravenous heparin at full dosage for 24 hours. The patency of the infarct-related coronary vessels was assessed by angiography 1 to 4 hours after administration of the thrombolytic agent. Clinical signs, ECGs, pulse, blood pressure and temperature were monitored regularly for 24 hours after treatment or as clinically appropriate. APSAC seemed to be at least as effective as streptokinase in terms of patency of the infarct-related vessel (92% vs 63%, respectively). The adverse events were similar and none was life-threatening. APSAC and streptokinase caused similar falls in blood fibrinogen levels. APSAC, given as a bolus injection over 5 minutes, was easier to administer than streptokinase, which was given as an infusion during 60 minutes.
Adult↗
Fibrinolysis in pregnancy: a study of plasminogen activator inhibitors.
During pregnancy the plasma concentration of two different inhibitors of plasminogen activators (PAIs) increases. The only one found in the plasma of nonpregnant women (PAI1) is immunologically related to a PAI of endothelial cells; its plasma activity, as deduced from the inhibition of single-chain tissue-type plasminogen activator (t-PA), increased from 3.4 +/- 2.3 U/mL (mean +/- 95% confidence limits) in the plasma of nonpregnant women to 29 +/- 7 U/mL at term, and its antigen level, measured by a radioimmunoassay, increased from 54 +/- 17 ng/mL to 144 +/- 25 ng/mL. In pregnancy plasma a second PAI (PAI 2) related to a PAI found in placenta extracts was observed. Its level, quantified with a radioimmunoassay, increased from below the detection limit (approximately 10 ng/mL) in normal plasma to 260 ng/mL at term. One hour after delivery, PAI 1 activities and antigen decreased sharply, but the PAI 2 antigen levels remained constant. Three days later, the PAI 1 antigen levels had fallen to normal levels, but the PAI 2 antigen levels were still at least eightfold above the nonpregnant values. During pregnancy, the t-PA and prourokinase (u-PA) antigen concentrations increased 50% and 200%, respectively, whereas the plasminogen and alpha 2-antiplasmin levels remained constant. Despite the large variations in the levels of PAs and PAIs, the overall fibrinolytic activity as measured in diluted plasma by a radioiodinated fibrin plate assay did not change significantly. Just after delivery, a great increase in the t-PA antigen levels was observed. Three to five days after delivery most parameters of the fibrinolytic system were normal again. Our results demonstrate that during pregnancy and in the puerperium profound alterations of the fibrinolytic system occur that are characterized by increases in PAs and their inhibitors, but these alterations do not affect the overall fibrinolytic activity.
Adult↗
Plasminogen activator inhibitor 1: development of a radioimmunoassay and observations on its plasma concentration during venous occlusion and after platelet aggregation.
To study the effect of plasminogen activator inhibitors (PAI) on fibrinolysis it is essential to be able to specifically measure these proteins in plasma. To this end PAI-1 was purified from cortisol-stimulated HT 1080 fibrosarcoma cells and antisera raised in rabbits. The immunologic relationship of the purified inhibitor to PAI-1 in plasma and platelet extracts was established by immunoblotting and regular and reverse fibrin zymography. Furthermore, the purified product could be immunoprecipitated with antibodies to human or bovine endothelial cell-derived PAI-1. A radioimmunoassay was developed that measures both free and tissue-type plasminogen activator (t-PA)-bound PAI-1 in plasma and has an effective range of 8 to 250 ng/mL. PAI-1 antigen levels showed a twofold increase after 20 minutes of venous occlusion, partially due to hemoconcentration. Approximately one quarter of PAI-1 before and after venous occlusion is derived from platelets. After correction for hemoconcentration and the contribution of platelets to plasma PAI-1 levels, a still significant increase in PAI-1 levels was noted during venous occlusion, which suggests that the local vascular bed releases PAI-1. Concomitant with PAI-1, t-PA antigen levels increased eightfold and fibrinolytic activity 18-fold after 20 minutes of venous occlusion. PAI-1 and t-PA levels tend to augment with age: in a group of older healthy volunteers (mean age, 53 years) PAI-1 levels were twice and t-PA levels 1.7 times higher than those in a group with a mean age of 29 years. Determination of PAI-1 antigen levels before and after platelet aggregation demonstrated that 85% of PAI-1 in platelet-rich plasma is associated with platelets. The average amount of PAI-1 per platelet was 0.3 fg/platelet, ie, 4,000 molecules per platelet.
Adult↗
[Aspirin as a platelet antiaggregant: indications and controversies].
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Arteriovenous Shunt, Surgical↗
Plasminogen activators, plasminogen activator inhibitors and procoagulant analyzed in twenty human tumor cell lines.
We have analyzed the CM of 20 human tumor cell lines for the presence of PA, PA-I and PC. Most of the cell lines expressed PA activity as measured by a radioiodinated fibrin plate assay. The urinary type and tissue-type PA activities were specifically quantified by means of purified inhibitory antibodies. U-PA and/or t-PA antigen, as measured by radioimmunoassays, were detected in all but 4 of the CM and were generally 10 times more concentrated than PA activity, indicating the presence of specific PA-Is. Analysis of CM by electrophoresis followed by fibrin-agarose zymography demonstrated the presence not only of free but also of inhibitor-complexed PA. Affinity purification demonstrated that 8/20 cell lines expressed detectable PA-I activity. The PA-I1 and PA-I2 inhibitors were most frequently observed, while PN was recovered only from CM of the HT1080 fibrosarcoma cell line. PC activity, as measured by the plasma recalcification time method, was found in 9/20 CM. It was of the thromboplastin tissue factor type since most of its activity was lost when assayed with a Factor VII-deficient plasma.
Blood Coagulation Factors↗
High-affinity binding sites for human Glu-plasminogen unveiled by limited plasmic degradation of human fibrin.
The binding of human 125I-Glu-plasminogen to human plasmin-degraded fibrin was studied. Treatment of preformed and polymerized fibrin with 0.01 IU plasmin/ml resulted in an increased binding of 125I-Glu-plasminogen depending upon the length of time of preincubation of fibrin with plasmin. Binding reached a plateau of 30% of total added radioactivity after 60 min. At this time, less than 10% of fibrin had been digested. Polyacrylamide/urea/acetic acid gel electrophoresis revealed that the radioiodinated plasminogen bound to plasmin-degraded fibrin was of the Glu form. Computerized non-linear regression analysis of the binding experiments revealed that limited plasmic degradation of fibrin progressively generates high-affinity binding sites (Kd approximately equal to 0.3 microM) for Glu-plasminogen. At the time of maximal Glu-plasminogen binding approximately 5 high-affinity binding sites per 100 molecules of fibrin had been generated. The low-affinity type of binding sites were also identified. These observations describe a new mechanism which exquisitely modulates the plasmic breakdown of fibrin by a continuous renewal of high-affinity binding sites for Glu-plasminogen on the surface of the fibrin gel during the fibrinolytic process.
Binding Sites↗
Purification and characterization of a plasminogen activator inhibitor from the histiocytic lymphoma cell line U-937.
We report the production, purification, characterization, and partial amino acid sequence of a plasminogen inhibitor (PA-I). The starting material is culture fluid from phorbol myristate 13-acetate-treated U-937 cells and the isolation steps consist of preparative isoelectric focusing followed by affinity chromatography on Cibacron Blue-Sepharose. PA-I migrates as a closely spaced doublet of 47-kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis and forms covalent complexes with urokinase and two-chain tissue-type plasminogen activator, displaying second order rate constants of 0.9 X 10(6) M-1 s-1 and 0.2 X 10(6) M-1 s-1, respectively. Upon treatment with 1 M NH4OH, the covalent complexes were hydrolyzed, yielding a 35-kDa inhibitor fragment. A partial amino acid sequence of PA-I showed that it belongs to the antithrombin III family of inhibitors. PA-I is immunologically related to a PA-inhibitor from human placenta. mRNA from phorbol myristate 13-acetate-treated U-937 cells directed, in a rabbit reticulocyte derived cell-free system, the biosynthesis of only one 47-kDa protein that could be immunoprecipitated with anti-PA-I IgG, indicating that the two molecular forms of PA-I are the products of post-translational processing.
Amino Acid Sequence↗
Studies on the release of a plasminogen activator inhibitor by human platelets.
The relative contribution of platelets to plasminogen activator inhibitor (PA-inhibitor) activity in blood was investigated. From the difference in PA-inhibitor levels in platelet-poor plasmas of 12 donors (3 +/- 1 U/ml, mean +/- 95% confidence limits) and in the corresponding platelet-rich plasmas after induction of platelet aggregation by collagen, ADP or epinephrine (7 +/- 1 U/ml), it may be concluded that a greater amount of PA-inhibitor in blood is associated with platelets than with plasma. In collagen-stimulated platelets maximal release of PA-inhibitor and of beta-thromboglobulin (beta-TG) was attained within fifteen seconds, whereas in ADP-stimulated platelets the release of both factors was slower. In platelet-poor plasma no correlation was found between the level of PA-inhibitor and that of beta-TG. Thus, the PA-inhibitor found in plasma is not derived from platelets that had been stimulated after blood collection. The rate of complex formation and the Mr of the principal complexes of radioiodinated tissue-type plasminogen activator (t-PA) or urokinase (UK), in platelet-poor plasma, in platelet-rich plasma after platelet aggregation or in an extract of washed platelets was the same. Moreover, complexes of UK or t-PA with plasmatic PA-inhibitor or with the PA-inhibitor(s) from platelets bound to immobilized antibodies against bovine endothelial cell-derived PA-inhibitor. These results show that the PA-inhibitors in plasma and in platelets are very similar or identical.
Adenosine Diphosphate↗
The fast-acting inhibitor of tissue-type plasminogen activator in plasma is also the primary plasma inhibitor of urokinase.
We have compared the ability of a plasminogen activator inhibitor (PA-inhibitor) in human plasma, to form complexes with radioiodinated tissue-type plasminogen activator (t-PA) and high molecular weight urokinase (HMr-UK). Addition of 125I-t-PA (final concentration 10 IU/ml) or of 125I-HMr-UK (2 IU/ml) to a plasma containing 33 U/ml of PA-inhibitor resulted in the rapid formation of a 110,000 Mr complex of 125I-t-PA or a 95,000 Mr complex of 125I-HMr-UK with PA-inhibitor. Upon prolonged incubation of the plasma with 125I-HMr-UK a secondary complex of a Mr of 88,000 was observed, which probably derives from limited degradation of the 95,000 complex. Preincubation of the plasma with unlabelled t-PA, HMr-UK or LMr-UK at higher concentrations prevented the subsequent formation of complexes between radiolabelled PAs and the PA-inhibitor. These results thus demonstrate that t-PA and UK form complexes with the same PA-inhibitor. The rate of complex formation of 125I-t-PA or of 125I-HMr-UK with the plasma PA-inhibitor was similar (second order rate constant of association with PA-inhibitor in the order of 10(7) M-1s-1).
Glycoproteins↗
Human primary colon carcinomas xenografted into nude mice. I. Characterization of plasminogen activators expressed by primary tumors and their xenografts.
Analysis was made of plasminogen activator (PA) activities present in 0.125% Triton X-100 extracts of human primary colon carcinomas and of their respective serial subcutaneous xenografts in nude mice. A correlation between tumor invasiveness and PA expression was observed in that primary tumors exhibiting clearly invasive growth patterns demonstrated high concentrations of PAs while subcutaneous xenografts, exhibiting noninvasive pseudobenign growth, contained very low levels of PA activity. The decrease in fibrinolytic activity observed in subcutaneous xenografts was not due to an increase in inhibitors of fibrinolytic activity. Immunologic characterization of PAs in tumor extracts showed that over 90% of human PA activity was of the urokinase type. Furthermore, tumor-derived urokinase was shown to be present in a proenzyme form. It was resistant to diisopropyl fluorophosphate (DFP) and was not inhibited by purified PA inhibitor. However, after its activation into urokinase by plasmin, it was completely inhibited by DFP and PA inhibitor.
Adenocarcinoma↗