Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.69 (APC)
 16,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We describe here results from the United Kingdom National External Quality Assessment Scheme (UK NEQAS) Thrombophilia Screening Program, in which an average of 21% of 280 centers reported an incorrect diagnosis for a series of plasma samples. Three case studies are described, showing causes of error in individual laboratories, related to the source of reference plasma or reagents. Methodological bias is also described. For protein C (PC) assays 18% of centers reported PC deficiency in a patient homozygous for factor V Leiden. Studies in the NEQAS laboratory confirmed the effect of activated protein C resistance (APCR) on clot-based PC activity assays. Differences in results obtained for PS-deficient subjects with different protein S (PS) activity kits are reported; several subjects would be misdiagnosed as normal with one kit if the manufacturer's reported reference range was adopted instead of a locally determined reference range. Antithrombin (AT) assays were shown to vary in their sensitivity to different molecular defects in the antithrombin gene; 77% of centers employing human thrombin-based activity assays reported a normal AT level in a patient with antithrombin Cambridge II. Sensitivity of the APC resistance test in the absence of factor V-deficient plasma was shown to be improved through normalization of results, and errors in the genetic diagnosis of factor V Leiden and the P20210A prothrombin gene mutation are described. Errors in the diagnosis of thrombophilic defects can therefore be identified through participation in EQA programs, and following dissemination of information, improvements in diagnosis can be demonstrated.
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PMID:Multilaboratory testing in thrombophilia through the United Kingdom National External Quality Assessment Scheme (Blood Coagulation) Quality Assurance Program. 1570 77

Coagulation activation with intravascular fibrin formation is a general finding in patients with sepsis. Low coagulation factors may be caused by disseminated intravascular coagulation, as well as by loss of plasma and impaired hepatic synthesis in the course of sepsis. The leading clinical symptom in consumption coagulopathy is bleeding. Therefore, treatment mainly consists of substitution of coagulation factors and platelets. Meningococcal and pneumococcal, as well as some other infections may lead to sepsis-induced purpura fulminans, a condition associated with microvascular thrombosis, necrosis, and haemorrhage. A typical laboratory sign is a very low plasma protein C level. Treatment with protein C concentrate or recombinant activated protein C (Drotrecogin alfa, activated) has been shown to be beneficial in sepsis-induced purpura fulminans. Unfractionated heparin or low molecular weight heparin has been recommended for prophylaxis of venous thrombosis, but there are no clinical studies specifically on patients with sepsis. Antithrombin concentrate is used in patients with antithrombin deficiency treated with heparin for acute venous thrombosis or embolism, extracorporeal circulation procedures or other invasive procedures. There is no indication for general use of antithrombin concentrate in patients with sepsis even in patients with low plasma antithrombin levels. Drotrecogin alfa, activated, is used for treatment of patients with severe sepsis. Its use is not limited to patients with sepsis-induced disseminated intravascular coagulation, although these patients appear to benefit especially from this therapy.
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PMID:[Sepsis-associated coagulation disorders]. 1592 56

The haemostatic system is greatly modified during severe infections. The early activation of coagulation is triggered by tissue factor expression and secondary fibrinolysis impaired by the upregulation of fibrinolysis inhibitors. This imbalance is a major cause of subsequent organ dysfunction. Natural anticoagulants (Tissue factor pathway inhibitor (TFPI), Antithrombin (AT), and Protein C (PC) are consumed or inhibited in this pathological process justifying a therapeutic supplementation with these inhibitors to improve sepsis-induced organ failure and mortality. No effect on the mortality rate could be documented in controlled studies using recombinant TFPI or AT concentrates but a biological interaction with heparin therapy could have biased the results. Treatment with recombinant activated PC was associated with a significant reduction in the mortality rate of severely ill patients. An increase in the rate of hemorrhagic adverse effects was observed with these compounds, justifying a strict observance of contraindications and of patient selection.
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PMID:[Hemostasis disorders in severe infections: state of the art]. 1719 28

The haemostatic system is greatly modified during severe infections. The early activation of coagulation is triggered by tissue factor expression and secondary fibrinolysis impaired by the upregulation of fibrinolysis inhibitors. This imbalance is a major cause of subsequent organ dysfunction. Natural anticoagulants (Tissue factor pathway inhibitor (TFPI), Antithrombin (AT), and Protein C (PC) are consumed or inhibited in this pathological process justifying a therapeutic supplementation with these inhibitors to improve sepsis-induced organ failure and mortality. No effect on the mortality rate could be documented in controlled studies using recombinant TFPI or AT concentrates but a biological interaction with heparin therapy could have biased the results. Treatment with recombinant activated PC was associated with a significant reduction in the mortality rate of severely ill patients. An increase in the rate of hemorrhagic adverse effects was observed with these compounds, justifying a strict observance of contraindications and of patient selection.
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PMID:[Hemostasis disorders in severe infections: State of the art]. 1671 62

Coronary artery bypass grafting with cardiopulmonary bypass can induce systemic inflammatory response syndrome. To assess the prevalence of preoperative antithrombin and protein C deficiencies in relation to the incidence of this syndrome, antithrombin and protein C levels were measured in 130 patients undergoing coronary artery bypass grafting with cardiopulmonary bypass. Systemic inflammatory response syndrome developed in 36 (27.7%) patients who were predominantly male, had a lower EuroSCORE, longer cardiopulmonary bypass time, higher pre-bypass temperature, and shorter activated coagulation time. Logistic regression showed that predictive factors included bypass duration and pre-bypass temperature; however, low antithrombin levels appeared to be a negative predictive factor. Antithrombin levels were < 80% in 33.8% of patients, and 11.6% had protein C levels < 80%. Postoperative antithrombin and protein C deficiencies are not uncommon in adults undergoing cardiac surgery with cardiopulmonary bypass, but detection of these deficits did not identify patients at increased risk of systemic inflammatory response syndrome.
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PMID:Antithrombin and protein C in systemic inflammatory response syndrome. 1724 21

Heparinization requires monitoring, but optimal methods for measuring the anticoagulant effects of heparin remain to be determined. We compared prothrombinase-induced clotting time (PiCT) and two chromogenic anti-factor Xa activity (anti-Xa) assays in monitoring high-dose heparinization during cardiopulmonary by-pass (CPB). Heparin effects were serially measured with PiCT and two anti-Xa assays in 100 patients. Antithrombin and protein C activities were measured preoperatively, and antithrombin activity was measured during CPB. Activation of coagulation was assessed with measurements of prothrombin fragment F1+2, soluble fibrin complexes, and D-dimer before, during, and after CPB. During CPB mean ranges of PiCT and of anti-Xa heparin levels measured with (anti-Xa A) and without (anti-Xa B) dextran sulfate and antithrombin supplementation were 5.0-5.2, 4.7-5.0, and 4.5-4.9 IU/ml, respectively. There was poor agreement between PiCT and anti-Xa and between the two anti-Xa assays (r = 0.32-0.65 and broad limits of agreement). Patients with low preoperative antithrombin or protein C levels had lower PiCT (p = 0.028 and p = 0.01) and anti-Xa A (both p<0.001) levels during CPB than others. Patients with the lowest heparin activities during CPB (lowest deciles of PiCT and anti-Xa A) had higher subsequent F1+2 after CPB (p = 0.002 and p = 0.02), and patients with high heparin levels required fewer transfusions of packed red blood cells than others. In conclusion, in the challenging setting of CPB there is poor agreement between anti-Xa assays and PiCT. However, coagulation-based PiCT could provide an alternative to the chromogenic anti-Xa assays. Higher heparin levels during CPB were confirmed to associate with reduced transfusion requirements.
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PMID:Monitoring high-dose heparinization during cardiopulmonary by-pass--a comparison between prothrombinase-induced clotting time (PiCT) and two chromogenic anti-factor Xa activity assays. 1827 95

Despite recent advances in supportive care, acute lung injury (ALI) and its more severe form acute respiratory distress syndrome (ARDS) are clinical entities with high morbidity and high mortality. In systemic inflammation, like sepsis, uncontrolled host defense can lead to systemic activation of coagulation on the one hand, and attenuation of fibrinolysis on the other. In ALI/ARDS similar but local disturbances in fibrin turnover occur, leading to excessive alveolar fibrin deposition compromising pulmonary integrity and function. Therapies in patients with sepsis have specifically focused on coagulation disturbances. Evidence from preclinical and clinical investigations suggests pharmacologically targeting pulmonary "coagulopathy" could be of benefit to patients with ALI/ARDS as well. Recent animal studies have demonstrated that administration of heparins, activated protein C (APC), Antithrombin (AT), Tissue factor-Factor VIIa (TF-FVIIa) pathway inhibitors, plasminogen activators (PA) and thrombomodulin (TM) can attenuate pulmonary coagulopathy and reduce lung injury and/or improve oxygenation. Some of these studies have also shown anti-inflammatory effects of treatment targeting at coagulation. To date there are no published studies that have specifically studied the effects of anticoagulants on ALI/ARDS however there are on-going clinical trials. A solid base has to be provided by preclinical studies to justify clinical studies on new pharmacologic therapies for ALI/ARDS. In this systematic literature review we give an overview of the models for ALI/ARDS that have been used so far on the topic of pulmonary coagulopathy and focus on the pharmacological interventions that have been evaluated with these models. Finally, the applicability of the different approaches for future research on this subject will be discussed.
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PMID:Pulmonary coagulopathy as a new target in lung injury--a review of available pre-clinical models. 1833 73

Epidemiological studies have shown that hormone therapy (HT) increases the risk of venous thromboembolism in post menopausal women. The mechanism of this increased risk is unknown; however, activation of the haemostatic system is known to contribute to the pathogenesis of venous thromboembolism. In post-menopausal women the estrogen/progestogen composition of the HT can influence the level of haemostatic activation. It was the objective of this study to compare changes in inhibitors and activation markers of the haemostatic system in healthy post-menopausal women taking estradiol (2 mg) combined with dydrogesterone or a new progestin, trimegestone. A multicentre study of 186 women randomised to six months therapy with either estradiol (2 mg) +trimegestone (0.5 mg) or estradiol (2 mg) +dydrogesterone (10 mg) was performed. Antithrombin and protein S activity was decreased and activated protein C (APC) resistance, D-dimer and prothrombin fragment 1.2, were increased in both groups on treatment. Protein C activity was decreased and plasmin-antiplasmin complex was increased in the trimegestone group only. The increase in plasmin-antiplasmin complex and D-dimer was greater after six cycles of treatment in the trimegestone group compared with the dydrogesterone group. In conclusion, decreased levels of inhibitors of blood coagulation and increased thrombin production were found in both groups however a greater increase in the levels of plasmin-antiplasmin complex and D-dimer was found in the trimegestone group. This suggests an enhanced fibrinolytic response in this group. Further studies are required to determine the significance of this finding with respect to venous thrombosis risk.
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PMID:Inhibitors and activation markers of the haemostatic system during hormone therapy: a comparative study of oral estradiol (2 mg)/ dydrogesterone and estradiol (2 mg)/ trimegestone. 1869 Mar 45

The pathogenesis and treatment of retinal vein occlusions (RVO) are largely unclear. Prevalence of cardiovascular risk factors and of thrombophilic abnormalities was evaluated in 117 patients (61 M, 56 F; mean age 51 +/- 13 years) with a history of RVO (62 central, CRVO; 48 branch, BRVO; 7 both) and in 202 age- and sex-matched control subjects. Cardiovascular outcome after a mean 8.2 year follow-up was recorded for 90 patients. Arterial hypertension was significantly more frequent in patients than in controls (64.9 vs. 28.2%; adjusted OR 4.5 95% CI 2.4-7.9; P < 0.0001), as well diabetes mellitus (17.9 vs. 7.9%; P < 0.05). Antithrombin, Protein C, Protein S and homocysteine levels, lupus anticoagulant, anticardiolipin antibodies, FV G1691A and prothrombin G20210A polymorphisms were comparable in the two groups, nor were different according to RVO localization or to the age at event. BRVO patients were significantly older (55 +/- 9 vs. 47 +/- 15 years; P = 0.002) and had higher prevalence of diabetes, overweight and hypertension (29.2 vs. 8.1%; 83.3 vs. 58.1%, 79.2 vs. 56.5%; P always <0.05). In 58/90 (64%) patients for whom clinical follow-up was available, new vascular events were recorded (coronary/cerebral, n = 38); only 22 patients (24%) received long-term antiplatelet agents (mostly aspirin 100 mg/d), with lower, but not statistically significant, prevalence of overall vascular recurrence (45.4 vs. 70.6%, P = 0.06). High rate of vascular recurrence is shown in patients with previous RVO, in which conventional cardiovascular risk factors play a major role, especially in BRVO and in older patients.
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PMID:Cardiovascular risk factors and outcome in patients with retinal vein occlusion. 1970 55

Vascular access thrombosis represents a serious and common problem in hemodialysis patients. Therefore, identification of relevant thrombotic risk factors could lead to an improved antithrombotic therapy. This case control study was performed to evaluate the relationship between some thrombophilias and vascular access thrombosis in hemodialysis patients. Seventy-eight patients undergoing dialysis (between May 2007 and September 2009) were selected as subjects. This sample was divided into two groups; a case group of 28 patients who had sustained one or more thrombotic events that resulted in vascular access failure and a control group of 50 patients, who had never had a thrombotic occlusion of a functioning permanent dialysis access. Antithrombin, protein C and protein S levels were measured. Also, both groups were tested for the factor V Leiden mutation, the prothrombin G20210A mutation, the methylene tetrahydrofolate reductase C677T and A1298C mutations. Among genetic mutations of factor V Leiden, prothrombin G20210A and methylene tetrahydrofolate reductase genes, the C677T methylene tetrahydrofolate reductase mutation was the only significant genetic cause of vascular access thrombosis (P=0.005). Our data demonstrated a significantly increased risk of vascular access thrombosis in carriers of the C677T methylene tetrahydrofolate reductase mutation.
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PMID:Role of thrombophilia in vascular access thrombosis among chronic hemodialysis patients in Tunisia. 2127 51


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