Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0024141 (systemic lupus erythematosus)
 44,322 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new prothrombin-based activated protein C resistance (APC-R) test is described. In this method, the patient sample is prediluted in a plasma depleted of factor V (FV). A reagent containing APC and a specific activator of FV is added. After an incubation period, clotting is initiated by the addition of the FV-dependent prothrombin activator Noscarin. We analyzed 703 samples from patients undergoing thrombophilia screening. By using a predefined cutoff ratio of 2.5, 100% sensitivity and specificity for the detection of a factor V Leiden (FVL) mutation was found. With a cutoff ratio of 1.2, a complete but narrow distinction of FVL heterozygous (n = 192) and FVL homozygous samples (n = 27) was determined. No interference by the international normalized ratio, activated partial thromboplastin time (aPTT), protein S activity, fibrinogen and factor VIII (FVIII) levels, or lupus anticoagulant ratio was detected. The new prothrombin-based APC-R assay provides improved distinction of FV wild-type and FVL carriers compared with the aPTT-based method. By the use of an FV-dependent prothrombin activator, the assay is not influenced by FVIII concentration or lupus anticoagulants.
 ...
PMID:Improved distinction of factor V wild-type and factor V Leiden using a novel prothrombin-based activated protein C resistance assay. 1553 75

Although antiphospholipid antibodies (aPL) are associated with thrombosis, it is not known who with aPL is at higher risk for thrombosis. It was the aim of this cross-sectional study to investigate how thrombophilic factors contribute to venous or arterial thrombosis in aPL-positive individuals. In outpatient test centres at two tertiary care hospitals, two hundred and eight (208) persons requiring aPL testing were matched by age, gender and centre to 208 persons requiring a complete blood count. Persons were classified as aPL-positive (having anticardiolipin, lupus anticoagulant and/or anti-beta(2)-glycoprotein I antibodies) or aPL-negative. Several thrombophilic factors were studied using logistic regression modelling. Results showed that the aPL-positive group had three-fold more events (37%) than the aPL-negative group (12%). In unadjusted analyses, clinically important associations were observed between factor V Leiden and venous thrombosis, hyperhomocysteinemia and arterial thrombosis, and activated protein C resistance (APCR) and venous thrombosis (OR, 95% CI = 4.00, 1.35-11.91; 4.79, 2.03-11.33; and 2.03, 1.03-3.97, respectively). After adjusting for recruitment group, persons with both APCR and aPL had a three-fold greater risk (OR, 95% CI = 3.31, 1.30-8.41) for venous thrombosis than those with neither APCR nor aPL. Similarly, after adjusting for hypertension, family history of cardiovascular disease, gender and recruitment group, persons with both hyperhomocysteinemia and aPL had a five-fold increased risk (OR, 95% CI = 4.90, 1.37-17.37) for arterial thrombosis compared to those with neither risk factor. In conclusion, APCR phenotype and hyperhomocysteinemia are associated with a higher risk of venous and arterial thrombosis, respectively, in the presence of aPL.
 ...
PMID:Antiphospholipid antibodies and thrombosis: association with acquired activated protein C resistance in venous thrombosis and with hyperhomocysteinemia in arterial thrombosis. 1558 39

To study the etiological factors and pathogenisis of venous thrombi and their relations with anticoagulation and fibrinolysis, In 47 patients with venous thrombi anticardiolipin antibody (ACA) was detected by ELISA. lupus anticoagulant (LA) and anti-activative protein C resistance (APCR) were examined by coagulation test; factor V Leiden was determined by PCR; activity of anticoagulation and fibrinolysis of antithrombin (AT), protein C (PC), plasminogen (Plg) were detected by chromophore substrate methods. The results showed that ACA and/or LA were positive in 34% of patients with VT, most of which consisted of ACA IgG and LA; Plg was negative in 9.5% of patients; tPAI elevated in 8.3% of patients (much more than control group, P < 0.005); ATIII, PC, tPA were negative in 4.5%, 4.5%, 2.8% of patients, respectively (no significant difference with control groups, P > 0.05); ATIII, PC and Plg were negative constantly in one patient; factor V Leiden was not detected by PCR. There were no significant differences in anticoagulation and fibrinolysis between antiphospholipoprotein antibody (APA) negative subjects and APA positive subjects, 4 patients of which were positive in APCR, 3 patients were positive in ACA and/or LA, two out of three patients didn't achieved APCR reversion after mixing their blood plasma with normal blood plasma. It is concluded that antiphospholipoprotein antibody and abnormal fibrinolysis were the common pathological factors in venous thrombi. LA and/or ACA disturbs the anticoagulation aspect to develop into acquired APCR which may be a possible cause leading to thrombophilia.
 ...
PMID:[Relationship of antiphospholipoprotein antibodies of venous thrombi with anticoagulation and fibrinolysis]. 1563 50

Thrombophilia can be defined as an increased tendency to thrombosis. There are several defined risk factors for thrombosis, and these are generally separated into acquired and congenital factors. Congenital risk factors include deficiencies or defects in natural anticoagulants, such as antithrombin, protein C and protein S, and genetic polymorphisms such as prothrombin G20210A and the cleavage-resistant factor mutation, factor V Leiden, which leads to a condition known as activated protein C resistance. Acquired risk factors include antiphospholipid antibodies, detected as lupus anticoagulants, and/or anticardiolipin or anti-beta2-glycoprotein I antibodies. Elevated homocysteine, immobility, increasing age, surgery, cancer, poor nutrition, pregnancy, high levels of clotting factors, and use of oral contraceptives and hormone replacement therapy comprise other risk factors. Each of these constitutes an element of increased risk, which is compounded when concomitant. There is ongoing debate regarding relative and compound risks, the value of laboratory screening, whom to screen for with these markers, and the form and duration of clinical management. This report briefly explores, from a scientist's perspective, some important issues that are sometimes overlooked.
 ...
PMID:Diagnostic issues in thrombophilia: a laboratory scientist's view. 1570 70

We have conducted a series of multilaboratory surveys during the last 6 years to evaluate testing proficiency in the detection of congenital and acquired thrombophilia. For lupus anticoagulant (LA) testing, participant laboratories used a panel of tests, including activated partial thromboplastin time (aPTT; 100% of laboratories), kaolin clotting time (26 to 70%), and Russell's viper venom time (RVVT; 75 to 100%). Coefficients of variation (CVs) for assays ranged from 5 to 40%. RVVT assays appeared to be most sensitive and specific for detection of LA (fewer false-negatives or -positives), although laboratories performed best when they used a panel of tests. For congenital thrombophilia, tests evaluated comprised protein C (PC), protein S (PS), antithrombin (AT), and activated protein C resistance (APCR). Most participant laboratories performed PC using chromogenic (approximately 75%), or clot based (approximately 15%) assays, with few (< 10%) performing antigenic assessments. PS was most often assessed (approximately 60%) by immunological or antigenic assays, usually of free PS, or by functional or clot-based assays (approximately 40%). AT is usually assessed by functional chromogenic assays (approximately 95%). APCR was assessed using aPTT (approximately 50%) or RVVT (approximately 50%) clot-based assays, with the aPTT APCR typically performed using factor V-deficient plasma predilution, but the RVVT APCR typically performed without. Laboratories using the RVVT APCR generally performed better in detection of factor V Leiden-associated APCR, with the aPTT method group yielding higher false-negative and/or false-positive findings (approximately 5% of occasions). Some clot-based PC and PS assays appeared to be influenced by APCR status, and yielded lower apparent PC and PS levels with positive APC resistance. The overall error rate for PC, PS, and AT was approximately 2 to 8% (i.e., false-normal interpretations for deficient plasma or false-abnormal interpretations for normal plasma). The CVs for these assays ranged from 5 to 40%, with highest CVs typically obtained with PS assays.
 ...
PMID:Multilaboratory testing of thrombophilia: current and past practice in Australasia as assessed through the Royal College of Pathologists of Australasia Quality Assurance Program for Hematology. 1570 75

The quality control process is a critical feature of pathology best practice. In addition to internal quality control processes applied on a test-to-test or day-to-day basis, the participation of laboratories in external quality assurance programs (QAPs) is critical to achieving ongoing test accuracy. There are several such programs operating in the international arena. With respect to thrombophilia, these include the Australia-based Royal College of Pathologists of Australia QAP, the United Kingdom-based National External Quality Assessment Service, and the International Thrombophilia External Quality Assessment Scheme, based in the Netherlands. Although there are some similarities between the programs, some diversity is also apparent. Each of the programs assess for the common markers of congenital thrombophilia, such as antithrombin, protein C, protein S, and activated protein C resistance. Testing of some acquired markers of thrombophilia, such as lupus anticoagulant, and genetic tests such as factor V Leiden and prothrombin G20210A mutation, are also available. This report focuses on some recent trends from these programs.
 ...
PMID:Learning from peer assessment: the role of the external quality assurance multilaboratory thrombophilia test process. 1570 79

Vascular access thrombosis is the most common and costly complication in hemodialysis patients. The role of thrombophilia in access thrombosis is not established. A case-control study was conducted of 419 hemodialysis patients to determine whether thrombophilia was associated with arteriovenous fistula or graft thrombosis. Participants were enrolled from three in-center and five satellite dialysis units associated with a Canadian academic health science center that provides dialysis services in a catchment area of one million. Patients were tested for factor V Leiden, prothrombin gene mutation, factor XIII genotype, methylenetetrahydrofolate reductase genotype, lupus anticoagulant, anticardiolipin antibody, factor VIII, homocysteine, and lipoprotein (a) concentrations. Overall, 59 (55%) patients with access thrombosis had at least one thrombophilia compared with 122 (39%) patients without access thrombosis (unadjusted odds ratio [OR], 1.91; 95% confidence interval [CI], 1.23 to 2.98). After controlling for important risk factors, the association between any thrombophilia and access thrombosis remained (adjusted OR, 2.42; 95% CI, 1.47 to 3.99). For each additional thrombophilic disorder, the odds of access thrombosis increased significantly (adjusted OR, 1.87; 95% CI, 1.34 to 2.61). This study suggests that thrombophilia is associated with access thrombosis in dialysis patients. Large, multicenter, prospective cohort studies are needed to confirm the observations from this case-control study.
 ...
PMID:Thrombophilia and the risk for hemodialysis vascular access thrombosis. 1572 80

Although patients undergoing cardiac surgery often present with diverse comorbidities, those with coagulation derangements are especially challenging. The present report describes the management of a patient who presented with a Factor V Leiden mutation, lupus anticoagulant, and acquired activated protein C resistance. A 42-year-old female presented with acute shortness of breath and chest pain. She was otherwise healthy 1 month prior to admission when she presented with dysfunctional uterine bleeding, resulting in the transfusion of three units of packed red blood cells. Coagulation evaluation revealed that the patient had lupus anticoagulant, factor V Leiden mutation and an activated protein C resistance. The patient presented with an acute myocardial infarction and was found to have 90% stenosis of her left main coronary artery, moderate mitral and tricuspid regurgitation, and a left ventricular ejection fraction of 25%. An emergent off-pump coronary artery bypass procedure with placement of a vein graft to the left anterior descending artery was completed. Intraoperative thrombophilia was encountered as evidenced by both an elevated thromboelastograph coagulation index (+3.6) and an acquired antithrombin-III deficiency. Postoperatively, the patient was placed on low molecular weight heparin, but developed heparin-induced thrombocytopenia and was switched to a direct thrombin inhibitor, argatroban. The following case report describes the coagulation management of this patient from the time of admission to discharge 43 days later, and the unique challenges this combination of hemostatic defects present to the clinicians.
 ...
PMID:Coagulation management of a patient with factor V Leiden mutation, lupus anticoagulant, and activated protein C resistance: a case report. 1591 49

Previous studies have shown an increased risk of retinal vein occlusion (RVO) in patients with hypertension, hypercholesterolemia and diabetes mellitus. Literature on the association between thrombophilic factors and RVO consists of small studies and case reports. The objective was to determine the relationship between thrombophilic risk factors and RVO. Thrombophilic risk factors analyzed were hyperhomocysteinemia, MTHFR gene mutation, factor V Leiden mutation, protein C and S deficiency, antithrombin deficiency, prothrombin gene mutation, anticardiolipin antibodies and lupus anticoagulant. For all currently known thrombophilic risk factors odds ratios for RVO were calculated as estimates of relative risk. The odds ratios were 8.9 (95% CI 5.7 - 13.7) for hyperhomocysteinemia, 3.9 (95% CI 2.3 - 6.7) for anticardiolipin antibodies, 1.2 (95% CI 0.9 - 1.6) for MTHFR, 1.5 (95% CI 1.0 - 2.2) for factor V Leiden mutation and 1.6 (95% CI 0.8 - 3.2) for prothrombin gene mutation. In conclusion, regarding thrombophilic risk factors and RVO there is only evidence for an association with hyperhomocysteinemia and anticardiolipin antibodies, factors that are known as risk factors for venous thrombosis as well as for arterial vascular disease. The minor effect of factor V Leiden mutation and the protrombin gene mutation (risk factors for venous thrombosis only) suggests that atherosclerosis might be an important factor in the development of CRVO.
 ...
PMID:Retinal vein occlusion: a form of venous thrombosis or a complication of atherosclerosis? A meta-analysis of thrombophilic factors. 1596 81

Thromboembolic events during the perinatal period are responsible for irreversible brain damage owing to cerebral hypoxia and neuronal necrosis. We investigated the presence of thrombophilia risk factors in children with congenital neurologic disorders. Nineteen children (9 males and 10 females), aged 1 to 14 years (median 4.5 years), who had presented with symptoms and signs of congenital neurologic disorders were studied. Thirty-five age-matched healthy children recruited from the same geographic area served as controls. Three patients of 19 (15.8%) were carrying the factor V Leiden mutation compared with 2 children among the controls (5.7%). One patient was heterozygous for the prothrombin G20210A variant (5.2%) compared with one child who was heterozygous among the controls. Three patients were homozygous (15.8%) and 11 were heterozygous (57.9%) for the C677T 5,10-methylenetetrahydrofolate reductase gene mutation compared with 4 (11.5%) and 18 (51.4%), respectively, among the controls. Three patients of 19 (15.8%) were carrying more than one mutation. We found 18 mutations in 79% (15/19) of the patients and 25 mutations in 69% (24/35) of the healthy children. Among the individuals carrying the homozygous 677TT 5,10-methylenetetrahydrofolate reductase genotype, we found 7 mutations in 32% (6/19) of the patients and 7 mutations in 20% (7/35) of the healthy children (P > .05). In one patient, lupus anticoagulant and antiphospholipid antibodies of IgG isotype were detected. Reduced activities of protein C, protein S, or antithrombin III were not observed in either the patient or the control group. Although, among our cases, we found some well-known risk factors associated with thrombosis in adults, the pathogenesis of these clinical entities remains obscure.
 ...
PMID:Genetic risk factors associated with thrombosis in children with congenital neurologic disorders. 1599


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>