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Protein C Resistance (protein + c_resistance)
Kinds of Protein C Resistance Selected AbstractsDouble inherited thrombophilias and adverse pregnancy outcomes: Fashion or science?JOURNAL OF OBSTETRICS AND GYNAECOLOGY RESEARCH (ELECTRONIC), Issue 5 2010Giovanni Larciprete Abstract Aim:, To determine to what extent double inherited thrombophilias are associated with adverse obstetric complications correlated with fetoplacental insufficiency, such as preeclampsia, hemolytic anemia elevated liver enzymes and low platelet count (HELLP) syndrome, gestational hypertension, fetal growth restriction (FGR), intrauterine death (ID), abruptio placentae and disseminated intravascular coagulopathy. Methods:, Pregnant women coming to delivery were retrospectively divided into two groups: group A (controls) and group B (cases). Patients belonging to group B had one of the following: severe preeclampsia, HELLP syndrome, gestational hypertension, FGR, intrauterine death, abruptio placentae of disseminated intravascular coagulopathy. We detected methylenetetrahydrofolate reductase (MTHFR) A1298C, MTHFR C677T, factor V Leiden, PAI-1, mutant prothrombin G20210A, plasma homocysteine, antithrombin III, protein S and activated protein C resistance. Normal pregnant women or pregnant women with double defects were enrolled in this study. Results:, The combination of MTHFR C677T mutation with PAI-1 (5G/5G) mutation was significantly linked with the occurrence of ID. HELLP syndrome was significantly related to the simultaneous presence of factor VIII and X mutations. The combination of MTHFR C677T with factor VIII mutation and the combination of factor II and V mutations were significantly related to the occurrence of abruptio placentae. We found an association between double isoforms MTHFR mutation and FGR. Conclusion:, It seems that some thrombophilias and a combination of thrombophilic factors carry a greater risk than others for a given adverse outcome. Further studies are needed to check the link between thrombophilic gene mutations and adverse pregnancy outcomes, such as recurrent miscarriages and deep venous thrombosis. [source] Increased acquired activated protein C resistance in unselected patients with hematological malignanciesJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 9 2008H. F. S. NEGAARD Summary.,Background: We have previously found that activation of coagulation in patients with various hematological malignancies was apparently not initiated by tissue factor (TF). Acquired activated protein C (APC) resistance may be another mechanism responsible for such hypercoagulation, and has been demonstrated in patients with solid tumors, but not in patients with hematological malignancy. Objective: To investigate acquired APC resistance in a hypercoagulable cohort of patients with hematological malignancies. Patients/methods: Blood samples from 93 patients with acute myeloid leukemia (AML), chronic lymphatic leukemia, multiple myeloma, or non-Hodgkin's lymphoma, were analyzed before start and after completion of cancer therapy. APC resistance was measured using calibrated automated thrombography. The APC sensitivity ratio (APC-SR) was calculated as the ratio of the endogenous thrombin potential (ETP) determined in plasma probed with either APC or buffer. Results: Untreated patients were found to have higher APC-SR than healthy controls, and patients with AML had higher APC-SR as compared to the other diagnoses, both findings being consistent with acquired APC resistance. The acquired APC resistance was partly ameliorated with cancer treatment. Decreased levels of protein S and TF pathway inhibitor were inversely correlated to APC resistance. Conclusions: APC resistance may contribute to the hypercoagulable state in hematological malignancies. [source] Activated protein C resistance determined with a thrombin generation-based test is associated with thrombotic events in patients with lupus anticoagulantsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 11 2007S. LIESTØL Summary.,Background:,Several studies suggest that antiphospholipid antibodies interfere with the activity of activated protein C (APC). This acquired form of APC resistance has been proposed as a possible pathogenic mechanism underlying hypercoagulability associated with the antiphospholipid syndrome (APS).Objectives:,We wanted to investigate the inhibitory effect of recombinant APC (rAPC) on ex vivo thrombin generation in plasma and the modification of this effect by the presence of lupus anticoagulants (LA).Patients/Methods:,We analyzed plasmas from 81 patients with LA (52 patients fulfilling the criteria for the APS) and 91 controls. Percent inhibition of the endogenous thrombin potential (ETP) as a parameter of APC sensitivity was determined in plasmas using a thrombin generation-based APC resistance test probed with rAPC. All results were normalized using pooled normal plasma (PNP) as a reference.Results:,Normalized percent inhibition of ETP by APC was lower in patients with LA [61.4%, 95% confidence interval (CI) 45.8,74.5%] compared to controls (107.8%, 95% CI: 107.1,109.3%). In patients with LA and APS, median inhibition was lower than in patients with LA without APS (44.6%, 95% CI: 30.1,55.7% vs. 78.8%, 95% CI: 73.9,95.8%). This difference also persisted when patients on warfarin therapy were excluded from the APS subgroup.Conclusions:,APC resistance can be demonstrated with a thrombin generation-based test in a majority of patients with the LA laboratory phenotype. A history of thrombotic events in patients with LA is associated with a stronger resistance to the anticoagulant effect of APC. [source] Mycoplasma pneumonia and pulmonary embolism in a child due to acquired prothrombotic factorsPEDIATRIC PULMONOLOGY, Issue 2 2008Sarah M.N. Brown MRCPCH Abstract We report on a child with Mycoplasma pneumonia, who developed an unexplained new oxygen requirement. He was found to have an ileo-femoral thrombosis and an acute pulmonary embolus, with positive anti-phospholipid antibodies and acquired activated protein C resistance. These are both acquired risk factors for venous thrombosis. He was successfully anti-coagulated and well at follow-up with disappearance of the anti-phospholipid antibodies, and normalization of his activated protein C activity. Children who present with Mycoplasma infections who run an atypical course should be monitored closely for signs of thrombosis. Thrombosis formation should also be considered in those children with deteriorating respiratory status, but little change in radiographical findings. Children found to have developed thrombi should be investigated with a full thrombophilia screen to elicit both congenital and acquired risk factors, and should be anti-coagulated appropriately. Pediatr Pulmonol. 2008; 43:200,202. © 2007 Wiley-Liss, Inc. [source] Platelet turnover, coagulation factors, and soluble markers of platelet and endothelial activation in essential thrombocythemia: Relationship with thrombosis occurrence and JAK2 V617F allele burden,AMERICAN JOURNAL OF HEMATOLOGY, Issue 2 2009Eduardo Arellano-Rodrigo Patients with essential thrombocythemia (ET) have an increased frequency of thrombosis, but the relationship of both thrombosis and JAK2 V617F allele burden with platelet turnover, acquired activated protein C resistance (aAPCR), and levels of coagulation factors and soluble markers of platelet, and endothelial activation is not well known. In 53 ET patients (26 with a history of thrombosis), reticulated platelets (RP) percentage, aAPCR, platelet tissue factor (TF) expression, and plasma levels of TF, coagulation factors, soluble P-selectin (sP-selectin), soluble CD40 ligand (sCD40L), von Willebrand factor antigen (VWF:Ag), soluble thrombomodulin (sTM), D -dimer and prothrombin fragment 1 + 2 were compared with those in matched healthy individuals and correlated with thrombosis occurrence and JAK2 mutational load. ET patients with thrombosis had significantly higher values for RP percentage, aAPCR, and levels of factors V and VIII, VWF:Ag, sP-selectin, and sCD40L than patients without thrombosis and controls. At multivariate study, RP percentage, factor V levels, and aAPCR were independently associated with an increased risk of thrombosis. Patients with JAK2 mutation had significantly lower levels of free protein S (PS) and higher levels of TF, sP-selectin, sCD40L, VWF:Ag, and sTM than those with wild-type allele. A mutant allele dosage effect (, 12%) was observed for TF, sP-selectin, sCD40L, VWF:Ag, and PS levels. These results support a role for platelet turnover, factor V, and aAPCR in the thrombosis of ET as well as the association between JAK2 V617F allele burden and either decreased free PS or increased TF and soluble markers of platelet and endothelial activation. Am. J. Hematol., 2009. © 2008 Wiley-Liss, Inc. [source] Factor V I359T: a novel mutation associated with thrombosis and resistance to activated protein CBRITISH JOURNAL OF HAEMATOLOGY, Issue 3 2003A. D. Mumford Summary. We report a kindred in which two siblings suffered spontaneous venous thromboses in the second decade of life. Further investigation showed reduced coagulation factor V (FV) activity and activated protein C resistance (APCR) ratio but no other thrombophilic abnormalities. The reduction in APCR ratio persisted in a modified APCR assay in which FV activity was normalized between test and control plasmas. Analysis of the FV gene showed that the thrombotic individuals had a complex genotype that included two novel point mutations c.529G>T and c.1250T>C resulting in FV E119X and FV I359T substitutions inherited on different alleles. Individuals in the kindred with FV E119X or FV I359T substitutions alone were asymptomatic. We suggest that the FV I359T substitution confers pro-thrombotic risk and APCR, but that this is only clinically manifest when co-inherited with the FV E119X allele. The FV I359T substitution creates a new consensus sequence for N-linked glycosylation within the FV heavy chain and we speculate that this abnormal glycosylation may disrupt activated protein C-mediated proteolysis of the variant FV and FVa. [source] Stroke in children: inherited and acquired factors and age-related variations in the presentation of 48 paediatric patientsACTA PAEDIATRICA, Issue 7 2009Francesca Del Balzo Abstract Aim:, Stroke is relatively rare in children and the clinical presentation of paediatric stroke is often subtle. Numerous predisposing risk factors are known, and these can be both inherited and acquired. They include cardiac disease, vascular abnormalities, endothelial damage, infectious diseases, collagen tissue diseases, certain inborn errors of metabolism and anticardiolipin antibody, lupus anticoagulant and deficiencies of protein C, protein S, antithrombin or plasminogen. In addition, abnormal activated protein C resistance (or Factor V Leiden), Factor II G20219A variant, and the thermolabile variant of methylenetetrahydrofolate reductase (MTHFR C677T) need to be considered. Methods:, To explore the prevalence of different predisposing conditions in paediatric stroke patients, we evaluated 48 patients, including subjects with ischaemic and haemorrhagic stroke subtypes. Results:, Only 7 out of 48 (14.5%) had no recognizable risk factors: the majority of paediatric stroke patients had pre-existing risk factors that predisposed to the condition. The major genetic risk factor in our series of patients was homozygosity for the MTHFR C677T mutation (7 out of 48 patients); three more patients were found to be heterozygous for the Factor V Leiden mutation. Acquired predisposing conditions were present in 23 out of 48 patients and included pulmunar stenosis, head trauma, hyperlipidaemia and varicella infection. A total of 17 patients had both genetic and acquired predisposing factors. Conclusion:, Our results emphasize that multiple predisposing risk factors commonly predispose to paediatric stroke. In addition, the primary clinical presentation appeared to differ between the older and younger children: hemiparesis was the typical presentation in children <1 year of age while seizure predominated in older children. [source] | ||||||||||