Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.6 (thromboplastin)
13,278 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The lupus anticoagulant (LA) phenomenon created world-wide interest recently. Various tests have been devised to identify LA in plasma, but none of these methods have been universally accepted. In this study 16 cases labelled LA positive by a prior kaolin clotting time (KCT) test were reassessed by four other methods, namely delta KCT (delta kaolin clotting time), APTT (activated partial thromboplastin time), PNP (platelet neutralization procedure), and DRVVT (dilute Russell viper venom time). Anti-cardiolipin antibodies (ACL) were also looked for. In our hands the delta KCT proved to be a simple, sensitive test, not influenced by oral anticoagulant therapy, and we recommend it as a screening test. Where the presence of LA is strongly suspected on clinical and other groups, more than one method may be necessary for the diagnosis.
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PMID:Comparison of four laboratory tests for lupus anticoagulant. 212

We determined the following coagulo-fibrinolytic activities in 24 patients with systemic lupus erythematosus (SLE) and 20 healthy adults: prothrombin time (PT), activated partial thromboplastin time (A-PTT), factor VIII: coagulant activity), von Willebrand factor antigen (vWF: Ag), antithrombin-III (AT-III), plasminogen (PLG), alpha 2 plasmin inhibitor (alpha 2 PI), alpha 2-plasmin inhibitor-plasmin complex (PIC), protein C (PC: activity and antigen concentration), and protein S (PS: total PS and free PS). PLG, AT-III, PC antigen concentration and total PS were significantly decreased in ten female controls as compared with ten male controls. Therefore, we used the ten healthy females as controls and excluded two male SLE patients in the analysis of the correlations of coagulo-fibrinolytic activities with lupus anticoagulant (LA), clinical and laboratory features in 22 female patients with SLE. In the SLE patients, PT was significantly shortened, while A-PTT was prolonged. PLG, PC activity and antigen, and total PS were significantly increased, and free PS levels were decreased in SLE. The shortened PT and decreased free PS suggest hypercoagulable states in SLE patients. A significant prolongation of A-PTT and a decrease of F VIII activity were observed in the six LA-positive SLE patients, and the results were considered as known effects of LA. Furthermore, vWF: Ag, AT-III and PC antigen levels were significantly increased in the LA-positive patients as compared with LA-negative patients. These changes indicate both vascular endothelial cell damages and a compensatory increase in coagulation inhibitors in the LA-positive patients.
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PMID:[Regulation of coagulo-fibrinolytic activity and lupus anticoagulants in systemic lupus erythematosus]. 212 31

Several assay systems have been proposed for detection of the lupus anticoagulant (LA). We compared several screening and confirmatory tests used for the detection of LA in 108 patients. LA was detected in 52 plasmas. The activated partial thromboplastin time (APTT) and the dilute Russell viper venom time (DRVVT) were the most sensitive screening tests as compared to the kaolin clotting time (p less than 0.001). The platelet neutralization procedure in both the APTT and DRVVT systems was superior to APTT performed with high phospholipid concentration (p less than 0.01) and tissue thromboplastin inhibition (p less than 0.001) as confirmatory tests. There was an association between the presence of LA and antiphospholipid antibodies detected by the enzyme-linked immunosorbent assay (p less than 0.001). In summary, our results show that APTT may be a sensitive test for the detection of LA when an appropriate reagent is employed, and that freeze-thawed platelets are more effective than phospholipids to neutralize LA activity.
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PMID:Comparison of various screening and confirmatory tests for the detection of the lupus anticoagulant. 212 55

IgG immunoglobulin preparations have been increasingly utilized to treat a variety of diseases. Since disease response to this form of therapy in patients with abnormal autoimmune function is often evaluated through the subsequent investigation of autoantibody levels, it is possible that autoantibody positivities reflect autoantibody reactivity of circulating immunoglobulin preparations and not of the patient's inherent B-cell activity. We therefore investigated three commercially available IgG immunoglobulin preparations separately for IgG, IgM and IgA autoantibody reactivity to six phospholipid antigens, total histone and four histone subfractions, and four polynucleotides. Universally, all three preparations demonstrated considerable IgG antiphospholipid and antihistone reactivity at dilutions of up to 1:10(3) but not antipolynucleotide reactivity. Although no IgM reactivity was detected in any of the preparations, in all three preparations surprising IgA reactivity, especially with antihistone specificity, was detected. No autoantibody reactivity was detected at dilutions compatible with physiologic conditions in vivo. Identical observations were made for lupus anticoagulant reactivity, which was evaluated by activated partial thromboplastin time (APTT) and tissue thromboplastin inhibition (TTI). Since autoantibody reactivities and prolonged APTT assays are observed only at pharmacologic dilution levels, it is unlikely that the administration of IgG immunoglobulin preparation will affect the evaluation of autoantibody levels in patients undergoing such treatment.
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PMID:Commercial IgG immunoglobulin preparations exhibit IgG and IgA autoantibody reactivity at pharmacologic but not at physiologic concentrations. 212 97

Anti-phosphatidylserine (APS) and anticardiolipin (ACL) antibodies were measured in 30 patients with lupus anticoagulant. In 17 cases there were clinical features of thrombosis (56.7%). The number of patients with IgG APS and ACL levels higher than seven standard deviations from the normal mean was significantly higher in the group with thrombosis (p less than 0.017 and p less than 0.02, respectively). The IgG APS level was higher in the group without systemic lupus erythematosus (p less than 0.029). There was a positive correlation between IgG APS and the activated thromboplastin time (r = 0.654, p less than 0.001). The correlation between IgG APS and IgG ACL was rho = 0.61. Two of the 5 patients with increased IgG APS and normal IgG ACL had thrombosis. We think that, in this group of patients, IgG APS titer may be, like IgG ACL, a biological marker of thrombosis risk.
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PMID:[Importance of antiphosphatidylserine antibodies in patients with lupus anticoagulant. Analysis of 30 cases]. 212 7

To clarify the pathogenesis of antiphospholipid antibody (aPL) syndrome, the reactivities of anticardiolipin antibodies (aCL) in sera of patients with systemic lupus erythematosus (SLE) or other diseases to fresh, activated or destroyed blood cells were examined by the inhibition assay using an enzyme-linked immunosorbent assay. In addition, the effects of lupus anticoagulants (LA) in the patients' plasma and of immune complexes formed between LA and PL antigens on platelet aggregations were also determined. The IgG-aCL activity of patients' sera was markedly inhibited by pre-incubation with freeze-thawed blood cells, including erythrocytes (RBC), mononuclear cells (MNC) and platelets, but not fresh platelets or RBC. The aCL activity was slightly inhibited by fresh MNC, and was definitely inhibited by thrombin-activated platelets and polymorphonuclear cells (PMN) stimulated with phorbol 12-myristate 13-acetate (PMA). However, the activity was not inhibited by platelets stimulated with adenosine 5'-diphosphate (ADP; 10 microM). Twenty-two LA positive plasma and 17 LA negative plasma from patients similarly enhanced the aggregation of platelets which were obtained from healthy adults and stimulated with low concentrations of ADP (1 or 2 microM). However, such enhancement of platelet aggregation was not observed when high concentrations of ADP (5 microM) or collagen (2 micrograms/ml) were used as stimulators. In four of the 16 LA positive plasma examined, the mixture of plasma and phospholipid reagent for activated partial thromboplastin time induced platelet aggregations without the other stimulations, but the plasmas themselves did not induce such a reaction. The above results indicate that the aPL from patients do not react with intact blood cells in vitro, but they can react with activated or destroyed blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Reactivities of antiphospholipid antibodies to blood cells and their effects on platelet aggregations in vitro. 212 28

We have compared the prevalence of antiphospholipid antibodies (APA) measured by enzyme-linked immunosorbent assay (ELISA), in 119 selected patients using five different antigens: bovine cardiolipin, phosphatidylserine, phosphatidylinositol, bovine partial thromboplastin and human brain partial thromboplastin. All the plasmas have been evaluated for the presence of lupus anticoagulant (LA) activity by clotting techniques. We found a significant association between the incidence of LA and APA (p less than 0.001), only moderate agreement between the prolongation of the activated partial thromboplastin time (APTT) and ELISAs (r around 0.50) and a good agreement between the ELISAs (r around 0.80). The combination of antibodies against cardiolipin (ACA) and human brain partial thromboplastin (AHPTA) allowed the detection of antibodies in most of the LA positive cases. ACA, AHPTA and antiphosphatidylinositol antibodies detected all the positive samples. Six patients (5%) had a single APA detected. The clinical associations of APA according to phospholipid specificity, immunoglobulin isotype and titer are shown.
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PMID:Clinical significance of various ELISA assays for detecting antiphospholipid antibodies. 212 55

Clotting assays allow qualitative rather than quantitative detection of the lupus anticoagulant. We have therefore studied the usefulness of an ELISA using a commercial partial thromboplastin, Throombofax, as antigen; the results obtained on 146 selected patient plasmas were compared to the results of coagulation tests (kaolin clotting time, tissue thromboplastin inhibition test, activated partial thromboplastin time) and of ELISAs using cardiolipin or phosphatidylserine as antigen. While satisfactory agreement was found within the group of coagulation tests or that of ELISAs, only a moderate agreement was obtained between clotting tests and ELISAs, the best being with the partial thromboplastin ELISA using low plasma dilutions. The study further indicates that ELISA techniques cannot entirely replace coagulation tests for the detection of a lupus anticoagulant, even when a partial thromboplastin is used as antigen. On the other hand, coagulation tests are less sensitive than ELISAs for the detection of antiphospholipid antibodies.
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PMID:Detection of lupus-like anticoagulants by an enzyme-linked immunosorbent assay using a partial thromboplastin as antigen; a comparative study. 212 56

A 27-year-old female with severe systemic lupus erythematosus with renal involvement developed extensive cutaneous hemorrhages 5 years after diagnosis. Routine coagulation tests confirmed a prolongation of activated partial thromboplastin time to 77 s. This was attributed to a marked reduction of factor VIII activity to less than 3%. An inhibitor with an activity of 1.4 Bethesda units against factor VIII was determined. Immunosuppressive therapy (steroids, azathioprin, cyclophosphamide, cyclosporine) had no influence on the hemorrhages. Later in the course of disease a life-threatening vaginal hemorrhage occurred in parallel with a flare-up of lupus activity. During that period a therapy of 7 S i.v. immunoglobulins (120 g within 5 days) was started. This led to an instant cessation of the bleeding. Factor-VIII activity rose from 3% ot 480% within 7 days and the ds-DNA-antibodies fell from 122 U/ml to 19.7 U/ml. Nine months later, under immunosuppressive therapy with cyclophosphamide and steroids, factor-VIII activity is still within the normal range and no bleeding episodes have occurred. This confirms the effectively of high-dose immunoglobulin therapy for hemophilia, due to acquired factor VIII antibodies, also in patients with severe SLE.
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PMID:[Long-term remission after i.v. immunoglobulin therapy in acquired antihemophilic factor hemophilia with systemic lupus erythematosus]. 212 57

The frequency of "Lupus anticoagulant" (LA), was studied in 51 patients with systemic lupus erythematosus (SLE), 15 patients with chronic immune thrombocytopenic purpura (ITP) and 3 other patients with prolonged partial thromboplastin time (PTT), two of which had suffered episodes of CVA, and the other had a diagnosis of Paroxysmal Nocturnal Hemoglobinuria. Lupus anticoagulant was determined in each patient by the plasma recalcification time and the Russell's viper venom clotting time. Eight patients with SLE, (15.6%) 6 with chronic ITP (40%) and the three patients with prolonged PTT were positive for LA. All patients with LA were female, whose ages ranged from 19 to 59 years, and all except two patients were under steroid therapy. Thrombocytopenia was the most frequent manifestation in the patients with LA, followed by recurrent fetal death and thrombosis. Only the patients with ITP had hemorrhagic complications and one of them also had CVA in one occasion. The immunosupressory therapy may have played a role in diminishing the frequency of LA in the patients studied.
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PMID:[Presence of lupus-type anticoagulant, in systemic lupus erythematosus and other clinical entities]. 212 14


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