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 antiphospholipid syndrome (APS) is characterized by the presence of pathogenic autoantibodies against beta2-glycoprotein-I (beta2GPI). The factors causing production of anti-beta2GPI remain unidentified, but an association with infectious agents has been reported. Recently, we identified a hexapeptide (TLRVYK) that is recognized specifically by a pathogenic anti-beta2GPI mAb. In the present study we evaluated the APS-related pathogenic potential of microbial pathogens carrying sequences related to this hexapeptide. Mice immunized with a panel of microbial preparations were studied for the development of anti-beta2GPI autoantibodies. IgG specific to the TLRVYK peptide were affinity purified from the immunized mice and passively infused intravenously into naive mice at day 0 of pregnancy. APS parameters were evaluated in the infused mice on day 15 of pregnancy. Following immunization, high titers of antipeptide [TLRVYK] anti-beta2GPI Ab's were observed in mice immunized with Haemophilus influenzae, Neisseria gonorrhoeae, or tetanus toxoid. The specificity of binding to the corresponding target molecules was confirmed by competition and immunoblot assays. Naive mice infused with the affinity-purified antipeptide Ab's had significant thrombocytopenia, prolonged activated partial thromboplastin time and elevated percentage of fetal loss, similar to a control group of mice immunized with a pathogenic anti-beta2GPI mAb. Our study establishes a mechanism of molecular mimicry in experimental APS, demonstrating that bacterial peptides homologous with beta2GPI induce pathogenic anti-beta2GPI Ab's along with APS manifestations.
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PMID:Bacterial induction of autoantibodies to beta2-glycoprotein-I accounts for the infectious etiology of antiphospholipid syndrome. 1190 Nov 88

A rapid, sensitive and specific flow cytometric assay has been developed for the determination of autoantibodies directed against platelet anionic phospholipids in antiphospholipid antibody syndrome (APLAS). The method is based on demonstrable competition between the placental anticoagulant protein I, annexin V, and the patients' autoantibodies on the platelet anionic phospholipids (the binding site for the prothrombinase complex; prothrombin and factors Va and Xa). The method is practical and rapid, uses readily available reagents, and involves standard equipment. The assay is inexpensive and cost-effective for both single and multiple samples. Results are provided within 2 hours from obtaining blood samples, thereby supporting clinical decision-making and management. Ten serum samples from patients with the clinical diagnosis of APLAS (48 tests), 10 from normal individuals (35 tests), and 10 from patients with immune thrombocytopenia (33 tests) were tested. Platelet preparations preincubated with normal sera showed high binding of fluorescein-labeled annexin V with an average fluorescence of 202.9 +/- 22.0 (arbitrary units). Patients with immune thrombocytopenia exhibited similar results, with an average fluorescence of 192.5 +/- 32.1 (P >.05). In contrast, incubation with sera from patients with APLAS resulted in a marked decline in the binding of annexin V to an average fluorescence of only 14.6 +/- 7.4 (P <.001). Preincubation with annexin V followed by the addition of patients' sera showed displacement of annexin V to a similar degree. Because annexin V attenuates procoagulant activity by competing with factors Va and Xa on the platelet anionic phospholipids, its displacement by patients' antibodies may result in the acceleration of procoagulant activity, thereby promoting thrombogenesis in APLAS.
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PMID:Antiphospholipid antibody syndrome: rapid, sensitive, and specific flow cytometric assay for determination of anti-platelet phospholipid autoantibodies. 1194 25

A 24-year-old Japanese man was admitted because of massive haematemesis and melaena with persistent abdominal pain. Markedly bloody ascites and severely oedematous small intestine were recognized, and angiography then revealed superior mesenteric vein thrombosis. After resection of the necrotic small intestine, continuous intravenous infusion of heparin and urokinase was performed. This patient had no familial or personal history of thrombosis. On the 15th day after operation, an initial search for lupus anticoagulant revealed that the prothrombin time (PT) ratio and dilute activated partial thromboplastin time (aPTT) were positive under heparin treatment, without evidence of rheumatic or connective tissue disease. Thrombocytopenia was observed with a nearly normocellular bone marrow. A follow-up examination 1 year later still revealed an increased aPTT. However, all tests for antiphospholipid antibodies had been negative including dilute aPTT for about 2 years since the 15th day after operation. These findings suggest that, in this patient, superior mesenteric vein thrombosis has not been associated with primary antiphospholipid syndrome but is probably idiopathic. Positive tests for lupus anticoagulant in the initial period may be unreliable due to heparin treatment.
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PMID:Superior mesenteric vein thrombosis presented transient false positivity for lupus anticoagulant under heparin treatment. 1198 2

The aim of the study was the assessment of the prevalence of antiphospholipid syndrome (APS) in patients with systemic lupus erythematosus (SLE). 72 patients with SLE had been investigated, 66 females and six males, aged 17 to 70 years, average 37.03. The presence of APA was determined using both ELISA assay for antiphospholipid antibodies, ASSERACHROM APA by Diagnostica Stago and clotting tests for lupus anticoagulant: activated partial thromboplastin time (aPTT), tissue thromboplastin inhibition test (TTI) and dilute Russell viper venom time (dRVVT). Antiphospholipid antibodies have been found in 24 patients (33.44%), 10 of them were with positive lupus anticoagulant tests, 6 of them were with positive ELISA test, while 8 of them had positive coagulation and immunological tests. Clinical manifestations that could be related to antiphospholipid syndrome were present in 22 patients (30.5%). The most common were thrombotic complications in 16 patients (22.25), recurrent spontaneous abortions in 7 patients (9.7%) and thrombocytopenia in 1 patient (1.39%). Presence of antiphospholipid syndrome was determined in 15 patients (20.83%). We can conclude that there is a significant correlation between presence of antiphospholipid antibodies and both thrombotic events and recurrent spontaneous abortions in SLE patients. Occurrence of thrombotic complications is in direct correlation with the level of antiphospholipid antibodies.
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PMID:Antiphospholipid syndrome accompanying systemic lupus erythematosus. 1207 Sep 37

The present study was designed to assess the impact of thymus ubiquitin complex (TUC) on morphological changes within the central nervous system (CNS) in pregnant rabbits with experimental antiphospholipid syndrome (APS). We also compared the intensity of neuropathological appearance and serological markers of the APS treated with the TUC. Post-mortem neuropathological investigations were done in 47 female New Zealand rabbits. The material was divided into 4 groups: Group I-23 pregnant animals with APS; Group II-7 pregnant rabbits with APS, treated with TUC; Group III-7 pregnant rabbits without APS, treated with TUC; Group IV (the control one)-110 pregnant animals without APS, untreated with TUC. The APS was induced by subcutaneous injections of cardiolipin. There were two main abnormalities within the CNS of pregnant rabbits, which could be a result of the APS: the thrombo-necrotic foci of nervous tissue, and perivascular or meningeal inflammatory infiltrates. It turned out that TUC application reduced the morphological abnormalities, but it did not eliminate them entirely. The number of cases with thrombo-necrotic changes was reduced by approximately 18%, while perivascular infiltrates by 36% respectively. The TUC application did not influence the meningeal infiltration. The platelet count significantly increased (p < 0.001), the activated partial thromboplastin time shortened (p < 0.001), and the number of immunised animals, demonstrating positive immunofluorescence test, significantly decreased after the TUC administration. The inflammatory changes within the CNS are the integral component of the experimental model of APS in pregnant rabbits. The TUC may decrease the inflammatory component of the APS in the CNS. The inflammatory infiltrates seem to be more responsive to TUC application and parallel to APS serological improvement after treatment than necrotic changes.
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PMID:The effect of thymus ubiquitin complex on neuropathological changes within the brain of pregnant rabbits with experimental model of antiphospholipid syndrome. 1212 Oct 39

Anti-beta -glycoprotein I antibody (abetaGPI) has been recognized in raising the risk of cerebral ischemia in patients with antiphospholipid antibody syndrome (APS), especially by protein C (PC) axis perturbation. Although a high potential is also seen in non-APS patients, the mechanism is substantially unknown. In the present study, we examined the effect of abetaGPI on PC and antithrombin-III (AT-III) activity in non-APS patients with non-cardiac cerebral ischemia (NCCI). A total of 111 NCCI patients and 30 healthy controls were enrolled. They were free of APS manifestation, and their anticardiolipin antibody and lupus anticoagulant tests were within normal range. There were 14.4% patients found to have an abnormal increase of blood abetaGPI. The PC, AT-III, albumin, aminotransferases, creatinine, prothrombin time and activated partial thromboplastin time did not differ between our patients and controls, or patients with or without increased abetaGPI. However, a marked decrease of the PC/AT-III ratio was found in patients with increased abetaGPI. The correlation between PC and AT-III activity was highly significant in patients with an increase of abetaGPI (P = 0.001), only marginal in controls (P = 0.042), and was insignificant in patients with a normal abetaGPI (P = 0.277). The abetaGPI did not correlate to PC or AT-III activity in either patients or controls. These findings suggest that high PC/AT-III coupling may relate to NCCI in non-APS patients associated with an increase of abetaGPI. This coupling effect seems not to be caused by abetaGPI directly.
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PMID:A perturbation of antithrombin-III and protein C coupling associates with an increase of anti-beta2-glycoprotein I antibody in non-antiphospholipid antibody syndrome cerebral ischemia. 1244 9

The activated clotting time (ACT) may be an unreliable monitor of coagulation for patients with the antiphospholipid syndrome. We describe a patient with antiphospholipid syndrome in whom adequate anticoagulation during cardiopulmonary bypass was confirmed by monitoring both the ACT and anti-factor Xa levels. The cardiopulmonary bypass was uneventful, and there were no thrombotic or bleeding complications. The use of anti-factor Xa levels provided confirmation of adequate anticoagulation (and reversal of anticoagulation) that was not possible using the ACT alone.
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PMID:Anti-factor Xa monitoring of anticoagulation during cardiopulmonary bypass in a patient with antiphospholipid syndrome. 1263 4

We describe a young woman whose initial presentation was dominated by acute diarrhoea. Life-threatening multiorgan failure rapidly ensued and necessitated mechanical ventilation and dialysis treatment. An initially elongated activated partial thromboplastin time prompted further coagulation tests that led to the detection of positive lupus anticoagulant, a highly elevated IgG-anticardiolipin (aCL) antibody titre, and prolonged dilute Russell's viper venom time. Histological examination of samples obtained during endoscopy revealed widespread intestinal thrombotic microangiopathy. In view of these serologic and histologic features, a diagnosis of the malignant variant of the antiphospholipid syndrome (APS), also termed 'catastrophic APS', was established. In spite of this syndrome's grim prognosis, the patient recovered following intensive anticoagulation and adjunct treatment with steroids and immunoglobulins.
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PMID:Catastrophic antiphospholipid syndrome masquerading as ischaemic colitis. 1267 77

Antiphospholipid syndrome (APS) is an uncommon prothrombotic disorder that has been increasingly recognized in recent years. The diagnosis of APS must be associated with venous or arterial thrombosis or both. Patients with APS usually present with recurrent deep vein thrombosis, pulmonary thromboembolism, thromboembolic stroke, or myocardial infarction. Here, we report a case of a 61-year-old female who presented with a 3-month history of increasingly frequent retrosternal chest tightness. After treadmill test and thallium-201 myocardial perfusion scan, she was admitted and underwent elective coronary angiography but developed acute thrombosis after direct intracoronary stenting. She was successfully rescued with repeat percutaneous transluminal coronary angioplasty and prolonged heparin and glycoprotein IIb/IIIa antagonist use. Laboratory data showed prolongation of partial thromboplastin time and positive anti-cardiolipin antibody. These findings satisfied the criteria for APS; the patient was diagnosed with primary APS because she had neither typical symptoms nor signs of systemic lupus erythematosus or other immunologic disorders. Thereafter, long-term oral anticoagulant appeared to be effective. To our knowledge, this is the first report of acute stent thrombosis in a patient with primary APS.
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PMID:Acute thrombosis after elective direct intracoronary stenting in primary antiphospholipid syndrome: a case report. 1279 47

As the activity of the tissue factor pathway inhibitor (TFPI) may be impaired in patients with antiphospholipid antibodies (aPL), 162 aPL patients were evaluated for autoantibodies to recombinant TFPI (anti-TFPI) using an optimized ELISA. Anti-TFPI (>18 U mL(-1) for IgG and/or > 15 U mL-1 for IgM) were detected in 54 patients with aPL (33.3%) and in three out of 79 normal controls (3.8%, P < 0.0001). Among aPL patients, the prevalence of positive anti-TFPI was 38.3 and 28.4% in those with or without diagnosis of definite antiphospholipid syndrome (APS). Patients with definite APS had a significantly greater frequency of high titer (>50 U mL(-1)) anti-TFPI than aPL patients from the no definite APS group (18.5% vs. 6.2%, OR 3.7, P= 0.017). Most aPL recognized full-length TFPI, but not a truncated form of TFPI lacking the C-terminus of the molecule. Isolated IgGs from subjects with anti-TFPI impaired the dose-dependent inhibitory effect of TFPI on factor Xa activity in the presence, but not in the absence of phospholipid vesicles. Thus, aPL with high titer anti-TFPI limit TFPI action and are associated with the APS.
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PMID:High titers of autoantibodies to tissue factor pathway inhibitor are associated with the antiphospholipid syndrome. 1287 6


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