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)

Eighty-three patients with circulating anticoagulants were studied at The New York Hospital. The lupus-type anticoagulant, an inhibitor of the prothrombin activator complex, was demonstrated in 58 patients. The inhibitor was identified using the blood and tissue thromboplastin inhibition tests. Inhibition by the lupus anticoagulant was augmented in 67% of these patients by a cofactor present in normal plasma. The lupus inhibitor was detected primarily because of an unsuspected abnormal coagulation test. One-half of the patients with the lupus-type anticoagulant did not have systemic lupus erythematosus.
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PMID:A clinical study of the lupus anticoagulant. 96 90

Four basic coagulation tests, the prothrombin time, thrombin time, partial thromboplastin time, and prothrombin consumption time, were used, with relatively simple modifications, to demonstrate the presence of two circulating anticoagulants in the blood of a patient with IgG myeloma and a severe bleeding tendency.
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PMID:Antithrombin and antithromboplastin activity accompanying IgG myeloma. Report of a case with a severe bleeding tendency. 111 Dec 75

A simplified dilute Russell's viper venom time (DRVVT) test--in which the venom, trace phospholipid and calcium were combined into a single reagent--was evaluated for the detection of lupus anticoagulants (LA) in 28 plasma samples containing non-specific circulating anticoagulants. In agreement with previous studies, the DRVVT was found to be insensitive to defects in contact and haemophilic factors and was only marginally affected by antibodies directed against factor VIII. Thus, the use of a DRVVT test in investigations of anticoagulants reduces the risk of confusing a haemorrhagic inhibitor of factor VIII with a non-haemorrhagic LA. In comparisons of sensitivity against activated partial thromboplastin time tests (APTT-Actin FSL and Organon-Teknika reagents) the simplified DRVVT was prolonged slightly more than the APTT in most of the test plasmas containing various non-specific circulating anticoagulants. Three anticoagulants affecting APTTs more than the DRVVT were found to be associated with anticardiolipin IgMs. APTT-prolonging anticoagulants, whether prolonging DRVVT tests or not, showed similar 'correction' of their APTTs by the addition of platelets or phospholipid. Thus, phospholipid-dependent or LA show heterogeneity. Those affecting only the APTT and not DRVVT should perhaps be classified differently.
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PMID:Use of a simplified dilute Russell's viper venom time (DRVVT) confirms heterogeneity among 'lupus anticoagulants'. 212 12

One hundred and fifty-seven HIV seropositive patients were included in a prospective study of coagulation parameters. Activated partial thromboplastin time, prothrombin time, thrombin time and specific factor assays of the intrinsic pathway were performed using standard techniques. The tissue thromboplastin inhibition test and antiphospholipid antibodies were used to establish the presence of circulating lupus anticoagulant. Among the 46 patients with a prolonged activated partial thromboplastin time, an anti-prothrombinase was present in 33. Of the 111 patients with a normal activated partial thromboplastin time, anti-prothrombinase was present in 51. Circulating lupus anticoagulant seems to be common in HIV seropositive patients, since it was found in 84 patients (53.5%). Our findings confirm that the presence of circulating anticoagulants is not particularly associated with opportunistic infections or the development of the disease. It is possible that these inhibitors could be mediated by anti-phospholipid antibodies. In HIV seropositive patients, defective T cell regulation of B cells leads to polyclonal hypergammaglobulinemia. These antibodies may be directed against endogenous or exogenous phospholipids.
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PMID:[Circulating anticoagulants in immunodeficiency virus infection. Results of a prospective study of 157 seropositive patients]. 259 85

The physiopathological role of antithromboplastin-type circulating anticoagulants in habitual abortion may be envisaged since the presence of antithromboplastin has been reported in most studies on women at high risk of abortion. To avoid a possible statistical bias, we conducted a prospective study in a sufficiently large group of women with habitual abortion (n = 99) compared with a control group of women with normal fecundity (n = 50). In addition, all women were investigated for lupus symptoms. The circulating antibody was detected by the diluted thromboplastin time and activated cephalin time methods. The results were considered positive when the patient/control diluted thromboplastin time ratio was 1.2 and/or when the increase in activated cephalin time was not corrected by a control plasma. In the patients' group, 10 women (10%) had an anti-thromboplastin type circulating anticoagulant, whereas no circulating anticoagulant could be detected in the control group. Three women with circulating anticoagulant had signs of systemic lupus erythematosus. None of the patients presented with Soulier-Boffa syndrome. These data have established a significant correlation between habitual abortion and circulating anticoagulant whilst avoiding statistical bias. Our results suggest that women with idiopathic habitual abortion should be subjected to systematic immunological exploration and that a small number of them should be followed attentively.
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PMID:[Immunological disorders of coagulation in habitual abortion. Prospective study]. 294 51

In an earlier report on the kidney in systemic lupus erythematosus (SLE), we described a subset of patients with circulating anticoagulants; many had glomerular and arteriolar thrombosis in the absence of necrosis and subendothelial deposits. The present study extends these observations to a larger group of patients with SLE and a circulating anticoagulant, and compares its findings with those in patients with SLE without evidence of an anticoagulant. It demonstrates (1) a higher prevalence of clinically recognizable thrombotic events in the venous and arterial circulations in patients with SLE and a detectable anticoagulant; (2) a probable shortening in life span; (3) a higher prevalence of glomerular thrombi; (4) elevated levels of factor VIII antigen and von Willebrand factor; and (5) significantly lower platelet counts and decreased in vitro platelet aggregation in response to adenosine diphosphate, epinephrine, and collagen. Since prednisone treatment often results in improvement or disappearance of a prolonged partial thromboplastin time, the test most commonly used for screening of a circulating anticoagulant, we suggest that the prevalence of this abnormality may be underestimated in patients with SLE.
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PMID:Thrombosis in systemic lupus erythematosus. Relation to the presence of circulating anticoagulants. 392 65

Endogenous circulating anticoagulants are unusual in children without a congenital factor deficiency. In particular, the lupus anticoagulant has only rarely been reported in children. Despite its functioning in vitro to prolong the partial thromboplastin time, patients more frequently have problems with thrombosis than bleeding, unless there is a coexistent prothrombin deficiency or thrombocytopenia. We report the cases of three children with the lupus anticoagulant. Two children had associated thromboses. One had a thrombosis of the iliofemoral system and the other had a partial Budd-Chiari syndrome, a thrombosis of the deep calf veins and ureteric obstruction. The third child had a concomitant prothrombin deficiency and bleeding after tooth extraction. Associated findings in these patients included a positive antinuclear antibody test in two, a positive anti-DNA antibody test in two, a false-positive VDRL test in two, and an antiphospholipid antibody test in two.
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PMID:Thrombotic and hemorrhagic complications in children with the lupus anticoagulant. 643 32

The introduction of the activated partial thromboplastin time (APTT) as a screening test has resulted in increased recognition of circulating anticoagulants. The most frequently encountered inhibitor is the lupus-type anticoagulant. However, criteria for differentiation of this inhibitor are not well-established. We evaluated the ability of two procedures, tissue thromboplastin inhibition (TTI) and a new platelet neutralization procedure (PNP), to differentiate between various types of coagulation inhibitors. The TTI, widely used for the diagnosis of lupus anticoagulants, proved to be nonspecific. The PNP specifically separated lupus-type inhibitors from Factor VIII, X, and V inhibitors. The PNP may be a useful test for the diagnosis of lupus anticoagulants.
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PMID:Laboratory diagnosis of lupus inhibitors: a comparison of the tissue thromboplastin inhibition procedure with a new platelet neutralization procedure. 684 58

A case of circulating anticoagulant resulting in persistent postoperative bleeding has been reported. All clotting factors were normal when the patient's plasma was tested in a high dilution. Unlike previous reports of this type of coagulation inhibitor, the hemorrhagic diathesis was clinically severe in comparison with the mildly abnormal in vitro tests. Many unknowns remain: the chemical nature of this anticoagulant; the time needed to return to normal coagulation levels; the frequency and severity of drug-induced anticoagulation; and the dose and duration of usage of medications resulting in circulating anticoagulants. In retrospect, the only clinical evidence suggestive of a coagulation problem in this case was a marginally elevated partial thromboplastin time. In our opinion, a preoperative coagulation screening, consisting of prothrombin time, partial thromboplastin time, platelet count, and template bleeding time, may help to prevent serious postoperative hemostatic complications.
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PMID:Postsurgical hemorrhage resulting from a drug-induced circulating anticoagulant: report of case. 696 61

Lupus anticoagulants (LA) have been defined as phospholipid-interfering antibodies. Testing for them has become a frequently requested procedure in coagulation laboratories and new methods have recently become available. Activated partial thromboplastin time (aPTT) reagents with reduced levels or different types of phospholipid provide high sensitivity. Correction procedures resistant to heparin and based on aPTT and dilute Russell's viper venom time (DRVVT) tests with added hexagonal phase phospholipids have improved the specificity of testing. Simplified tests based on venom activators of factor X and prothrombin improve the reliability of LA testing and may facilitate the further categorization of circulating anticoagulants. Recent studies on the mechanism of LA derived from various patients have confirmed their heterogeneity, principally in the protein cofactors involved in their interactions with phospholipids. Perhaps one-third of LA require beta 2-glycoprotein 1 to exert an anticoagulant effect. The remainder may require human prothrombin as suggested from studies with reconstituted clotting factor systems.
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PMID:Some recent developments with lupus anticoagulants. 805 62


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