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)

We studied both inherited and acquired activated protein C (APC) resistance in a group of 22 patients with primary antiphospholipid syndrome (APS). The APC resistance genotype was assessed using a PCR-based analysis for the factor V R506Q (Leiden) mutation. One patient with primary APS was found to be heterozygous for the factor V Leiden mutation. He and other family members were affected by severe thrombophilia and had a familial form of primary APS. The APC resistance phenotype was assessed by measuring the prolongation of the activated partial thromboplastin clotting time in response to APC. It was found in five out of six patients with APS, in one of them transiently. We have found that the APC resistance phenotype is more frequent than the genotype in primary APS. It would seem that patients with thrombophilia should be investigated for APC resistance even if found to have antiphospholipid antibodies and/or lupus anticoagulants.
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PMID:Activated protein C resistance phenotype and genotype in patients with primary antiphospholipid syndrome. 873 42

Recently it has been suggested that antiphospholipid antibodies may not be specific for phospholipids but directed to beta2glycoprotein 1 (beta2GP1), phospholipid-beta2GP1 complexes, prothrombin, or prothrombin-phospholipid complexes. To explore this issue further, we examined the influence of two phospholipid binding proteins, annexin V (placental anticoagulant protein I (PAP I)) and beta2GP1, on the activity of immunoglobulin G (IgG) fractions from patients with antiphospholipid syndrome (APS), both in the prothrombin-thrombin conversion assay and in the anticardiolipin enzyme-linked immunosorbent assay (ELISA). Results showed that each of eight IgG-APS; fractions, as well as PAP I and beta2GP1, individually inhibited the prothrombinase reaction. When IgG-APS samples were combined with PAP I or beta2GP1, or both PAP I and beta2GP1, inhibition of the prothrombinase reaction was additive. In the anticardiolipin ELISA, PAP I inhibited IgG-APS binding to cardiolipin, but beta2GP1 enhanced IgG-APS binding to cardiolipin. The "enhancing" effect of beta2GP1 in the ELISA system was neutralized by PAP I, an effect partially overcome by increasing the concentration of beta2GP1. Similar results were observed when affinity-purified anticardiolipin antibodies were used in place of whole IgG-APS preparations. These data indicate that IgG preparations obtained from the 8 patients with APS recognize similar epitopes; on anionic phospholipids in the anticardiolipin test and in the prothrombin-thrombin conversion assay. These data do not exclude the possibility that the IgG preparations may bind prothrombin-phospholipid or beta2GP1-phospholipid complexes.
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PMID:Studies on the interaction of placental anticoagulant protein I, beta 2 glycoprotein 1, and antiphospholipid antibodies in the prothrombinase reaction and in the solid phase anticardiolipin assays. 876 15

Antiphospholipid syndrome is characterized by recurrent episodes of arterial and venous thrombosis, spontaneous fetal losses, thrombocytopenia and persistently elevated levels of antiphospholipid antibodies. We experienced a case of Budd-Chiari syndrome in a 32-year old female lupus patient who was presented with left leg edema, ascites and esophageal varix. The clinical and laboratory findings were compatible with the cirteria for systemic lupus erythematosus (SLE) and she was found to have anticardiolipin antibody, thrombocytopenia and prolonged partial thromboplastin time. Initially, she was treated with intravenous heparin and uroki nase and she was followed up with warfarin, baby aspirin and steroids.
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PMID:A case of Budd-Chiari syndrome with high antiphospholipid antibody in a patient with systemic lupus erythematosus. 888 80

The first treatment of pregnant women with antiphospholipid antibody syndrome (APLS) employed high doses of corticosteroids, plus low dose aspirin, with the goal of suppressing production of the autoantibody. Corticosteroids (usually prednisone), even when much lower doses are used, and even when tapered after midpregnancy, have been associated with significant maternal and obstetric risks and side effects: the most important are osteomalacia and preterm delivery (often precipitated by premature rupture of the membranes). Since the publication of a randomized trial demonstrating equivalent live birth rates of about 75% whether heparin or prednisone was used for treatment (plus low dose aspirin), the use of adjusted doses of heparin, together with low dose aspirin, has replaced prednisone for treatment of pregnant women; although prednisone may still be needed to treat manifestations of associated autoimmune disorders. A recent randomized trial has shown that the addition of heparin to aspirin is probably superior to treatment with aspirin alone. To achieve prophylactic levels of plasma heparin equivalent to those measured in patients who are not pregnant and are treated with the usual dose of standard heparin of 5000 IU every 12 h, the heparin dose required for treatment of pregnant women is usually higher. For that reason, heparin doses should be adjusted using the nadir APTT, or better plasma heparin measured by a factor Xa inhibition assay at the 2 h post-injection peak. Although low molecular weight heparin has been shown to be useful in prevention of fetal resorption in a mouse model, and appears to be equally safe for treatment of pregnant women, we still have no published data to show therapeutic equivalency, with respect to treatment of APLS-complicated pregnancy, to standard heparin preparations, and none that demonstrate any lower risk for the complication of most concern when heparin is given to pregnant women-osteopenia. Similarly, intravenous infusion of gamma globulins (IVG) appears on the basis of case reports to be effective additional treatment in cases where standard therapy has failed. Gamma globulin preparations contain anti-idiotypic antibodies that have been shown to bind to patient antiphospholipid antibodies. The place for the addition of IVG to standard therapy has not been defined, but clinically significant and corticosteroid-resistant thrombocytopenia complicating antiphospholipid antibody syndrome might be one indication for primary treatment with IVG +/- low dose aspirin. Overall, live birth rates in most treatment studies are in the range of 70-80%. The reported birth rate information, however, cannot be compared between studies. None of the studies reported have used tools such as logistic regression analysis to allow for such significant predictors of live birth as the number of prior miscarriages, maternal age, medical history, or a history of fetal death (loss of a viable and chromosomally normal fetus after the 10th gestational week).
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PMID:Prevention of fetal death in the antiphospholipid antibody syndrome. 890 84

Patients with antiphospholipid antibody syndrome (APS) experience a higher rate of recurrence of thrombosis than the general population of patients with thrombotic disease. Based on a retrospective analysis, it has been suggested that patients with APS should be kept on prolonged anticoagulation aiming at international normalised ratio (INR) values > 3.0. To evaluate whether the requirement for more intense anticoagulation depends on the variable sensitivity of thromboplastin reagents to the influence of aPLA, we monitored oral anticoagulant treatment in 10 patients with persistent lupus anticoagulants (LA) and venous thromboembolic disease using two thromboplastin reagents: Pro-IL-Complex (Instrumentation Laboratory, combined) and Recombiplastin (Ortho, recombinant). Acenocoumarol dosage was always assigned based on INR values obtained with the combined thromboplastin using diluted (1:20) test plasma, aiming at an INR interval of 2.0 to 3.0. Single INR determinations with both reagents were obtained throughout the study period for 110 aPLA-free patients on stable oral anticoagulation. Using the manufacturer's instrument-certified international sensitivity index (ISI) values, INR obtained with the recombinant reagent were significantly higher than those obtained with the combined reagent in LA-positive patients, but they were lower in LA-negative patients. After correction for local ISI calibration in LA-negative patients, INR values of 3.1 and 4.6 with Recombiplastin corresponded, respectively, to INR values of 2.0 and 3.0 with Pro-IL-Complex. These results indicate the thromboplastin-dependency of INR values in patients with LA, thereby questioning the validity of the INR system for the monitoring of oral anticoagulant treatment in these patients.
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PMID:Potential failure of the International Normalized Ratio (INR) System in the monitoring of oral anticoagulation in patients with lupus anticoagulants. 895 52

Antiphospholipid syndrome is a paradoxical disease state with in vitro prolongation of activated partial thromboplastin time and a strong predilection for in vivo thrombosis. The syndrome can be associated with systemic lupus erythematosus or lupus-like diseases or may be primary, presenting with thrombotic phenomena in young patients with no risk factors for thrombosis. We present two cases seen in two different settings in the hospital.
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PMID:The anaesthetist and the antiphospholipid syndrome. 920 6

A 33-year-old man presented malar rash in April, 1992. The rash had gradually developed and he was admitted to our hospital in February, 1994. Laboratory findings showed proteinuria of 0.5-0.8 g/ day, thrombocytopenia (4.8 x 10(4)/mm3), false positive serologic test for syphilis, anti-nuclear antibody with a speckled type at a titer of 1 : 80. Activated partial thromboplastin time was prolonged (41.3 s), and anti-beta 2-GPI antibody was strongly positive (56.6 U/ml on enzyme linked immunosorbent assay). The diagnosis of systemic lupus erythematosus with antiphospholipid syndrome was made and prednisolone 60 mg/day improved his manifestations. He could be discharged in July, 1994. Nine months after the discharge he developed dyspnea, and he was admitted to our hospital again. On admission the blood pressure was 212/170 mmHg, Levine III/VI systolic murmur was noted at the apex of heart. Significant laboratory findings showed as follows: WBC 15, 110/mm3 (Neu 73%, Lym 18%), RBC 380 x 10(4)/mm3, Hb 10.2 g/dl, Plt 20.0 x 10(4)/mm3, GOT 23 IU/l, GPT 21.
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PMID:[Acute cardiac failure due to dilated cardiomyopathy in systemic lupus erythematosus with antiphospholipid antibody]. 912 25

beta2-Glycoprotein I (beta2GPI), a plasma glycoprotein with phospholipid-binding property, is known to be the actual target antigen for autoimmune type anticardiolipin antibodies (aCLs). Certain groups of aCLs (anti-beta2GPI antibodies) exert lupus anticoagulant (LA) activity and perturb the function of vascular endothelial cells. This investigation aimed at highlighting some insights into the molecular basis by which aCLs exert their biological effects by using anti-beta2GPI mAbs with well-characterized epitopes from mice and from patients with antiphospholipid syndrome. Anti-beta2GPI mAbs directed against the third domain (Cof-20 and Cof-22) and fourth domain (Cof-21, EY1C8, and EY2C9) of beta2GPI inhibited the thrombin generation induced by Russell's viper venom in diluted plasma and that induced by the prothrombinase complex reconstituted with purified clotting factors. This anticoagulant activity was abrogated in the presence of an excess amount of phospholipids, thus resembling the LA activity. In stark contrast, anti-beta2GPI mAbs directed against the fifth domain and the carboxy-terminal region of the fourth domain showed no LA-like activity. These findings suggest that the LA activity of anti-beta2GPI antibodies depends on their epitope specificity. Experiments carried out to clarify the mechanism of the LA activity showed that anti-beta2GPI mAbs with LA-like activity, but not those without this effect, enhance the beta2GPI binding to phospholipids. In addition, the F(ab')2 fragment, but not the Fab' fragment, of the anti-beta2GPI mAbs was found to enhance the LA activity and the beta2GPI binding to phospholipids, suggesting that anti-beta2GPI antibodies induce formation of multiple complexes of beta2GPI on the surface of phospholipids because of their bivalent property. This clustering of beta2GPI molecules induced by anti-beta2GPI antibodies, probably because of their multivalent property and epitope specificity, might hinder the lateral mobility and activation of clotting factors on the surface of phospholipids and thus exert LA activity. Clustering of beta2GPI molecules may also explain the molecular mechanism by which anti-beta2GPI antibodies alter the function of leukocytes and endothelial cells. The well-documented heterogeneous LA activity of aCLs (anti-beta2GPI antibodies) may also be explained by their epitope specificity.
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PMID:Anti-beta2-glycoprotein I (beta2GPI) monoclonal antibodies with lupus anticoagulant-like activity enhance the beta2GPI binding to phospholipids. 915

Bone marrow necrosis (BMN) is a relatively rare entity and has been associated with a poor prognosis. It is most commonly found in patients with neoplastic disorders, severe infections and sickle cell anemia. An unusual case of antiphospholipid syndrome (APS) with extensive bone marrow necrosis is described in a 27 year old woman. The patient presented with severe pancytopenia, some cognitive impairment resulting from a previous cerebrovascular accident, fever, hypertension, dyspnoea, tachycardia, hepatosplenomegaly, and vaginal bleeding. Her laboratory findings included a strongly positive Coombs' test (anti-IgG and anti-C3d), a prothrombin time of 23 seconds and an activated partial thromboplastin time of 45 seconds. Anticardiolipin antibody tests were positive. Antinuclear and anti-DNA antibodies were negative but the anti-SM test was positive. A bone marrow biopsy specimen was reported as showing extensive necrosis. The patient was treated with steroids, transfusion, and plasma exchange with some clinical improvement but her pancytopenia did not respond and necessitated frequent transfusions. This case lends further support to the association between APS and BMN.
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PMID:Bone marrow necrosis in antiphospholipid syndrome. 915 83

Autoimmune hemolytic anemia and adrenal insufficiency are rarely associated with the antiphospholipid antibody syndrome. A 49-year-old woman with a history of deep venous thrombosis and recurrent miscarriages was found to have active autoimmune hemolytic anemia after being admitted to the hospital for cholelithiasis. The patient was treated with corticosteroids and underwent laparoscopic cholecystectomy 1 month later. Two weeks after surgery she had acute adrenal insufficiency. Activated partial thromboplastin time was prolonged, and antiphospholipid antibodies were detected in significant titer. Her illness responded well to corticosteroid therapy. Her direct Coombs' test remained positive. It appears that the antiphospholipid antibody syndrome contributed to the development of venous thrombosis, recurrent miscarriages, autoimmune hemolytic anemia, adrenal insufficiency, and indirectly, pigment stone cholelithiasis in this patient.
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PMID:Autoimmune hemolytic anemia, primary adrenal insufficiency, and the antiphospholipid syndrome. 921 40


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