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)

A major adverse effect of recombinant human erythropoietin (r-HuEPO) in hemodialyzed patients are thrombotic events. Several reports on platelet function during r-HuEPO treatment have been published but less is known about fibrinolysis. In the present study, the fibrinolytic capacity was studied in 20 patients on maintenance hemodialysis and treated with r-HuEPO. The patients were randomized into two groups and investigated in a crossover design. r-HuEPO was administered intravenously and subcutaneously in each group and was given for 3 months, respectively. Plasma tissue plasminogen activator (t-PA) and released t-PA remained unaffected by r-HuEPO in both groups throughout the study. Tissue plasminogen activator inhibitor (PAI) increased in a cyclic way reaching peak values 4-6 weeks after the start of investigation and again 4-6 weeks after changing therapy. The increase in PAI was significant in the two groups (0.025 > p > 0.01). Tissue plasminogen antigen was low in the uremic patients. The influence of r-HuEPO on this parameter was not investigated. Compensatory changes in plasma levels of factor XII procoagulant activity, activated protein C and of alpha 2-antiplasmin were not observed. Thrombotic events occurred in 4 patients at peak values of PAI. Six patients required an increase in heparin dose simultaneously with the increase in PAI. Thus, r-HuEPO seemed to affect the fibrinolytic capacity of uremic patients.
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PMID:Fibrinolytic capacity in hemodialysis patients treated with recombinant human erythropoietin. 143 39

Thrombotic events occur frequently in myeloproliferative disorders, namely polycythaemia vera and essential thrombocythaemia. Standard diagnostic criteria are designed quite stringent, so that a number of patients could be underdiagnosed. Spontaneous erythroid colonies formation from bone marrow or peripheral blood in the absence of exogenous erythropoietin is considered a reliable index of myeloproliferative disorder even at early stages. Endogenous erythroid colonies (EECs) formation was assessed in 43 patients having recently suffered from venous thrombosis prior to 45 years and without a previous diagnosis of hematological disease favouring thrombosis. A screening for coagulative abnormalities associated with thrombophilia was also carried out: in 5 patients (11.6%) a plasmatic thrombogenic defect was found (quantitative deficiency of antithrombin III, 1 case, protein C, 2 cases, protein S, 1 case, and plasminogen, 1 case). In 10 patients (2 males and 8 females) (23.2%) EECs assay was positive, allowing diagnosis of myeloproliferative disease even though 7 of them did not fulfill standard diagnostic criteria. In the other 3 patients who met the criteria for diagnosis of overt myeloproliferative disease the thrombotic event was the inaugural manifestation. In all these EECs-positive patients thrombosis involved mesenteric and portal veins (n = 4), hepatic veins (n = 3), portal vein (n = 2), mesenteric vein (n = 1). One of them was simultaneously affected from congenital protein C deficiency. Thus latent or atypical forms of myeloproliferative disease as well as the overt stages were the most frequent recognized cause of splanchnic venous thrombosis, accounting for 55% of the cases of our series. On the contrary no EECs-positive subject was found among the 25 patients with other sites of thrombosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Hematological causes of venous thrombosis in young people: high incidence of myeloproliferative disorder as underlying disease in patients with splanchnic venous thrombosis. 164 18

Tremendous progress have been performed during the last 25 years in thrombosis. Thrombotic disease can result either from increased deposition or decreased dissolution of fibrin. Since the first observation of a familial antithrombin III deficiency, numerous inherited defects of antithrombotin III, protein C, protein S, heparin cofactor II and plasminogen have been described and were assumed to be responsible of a thrombophilic state. However a disparity in the clinical expression of heterozygous deficiency in coagulation inhibitors or molecular abnormalities of coagulation does exist. On one hand, the prevalence of such molecular diseases is not yet perfectly known and on the other hand, contributory factors (acquired environmental insults or other genetic abnormalities) could play a role in individuals already predisposed to thrombosis. The molecular genetics of deficiencies is going to help us to establish specific gene lesions and thromboembolic history relationships. The analysis of structural or regulatory mutations in the genes of the different coagulation inhibitors, of the molecules of the fibrinolytic system, and of the fibrinogen molecule will greatly increase our knowledge of the molecular basis of thrombosis. The influence of the genetic polymorphism of these molecules on the risk of thrombosis should be studied. Finally, cellular aspects of thrombosis including the role of blood cells and endothelial cells will bring lot of informations on the comprehension of thrombotic diseases.
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PMID:[Molecular basis of thrombosis]. 176 58

Two unrelated families are described, of which four adult members were found to be suffering from severe protein C deficiency (less than or equal to 5% of normal plasma level). Newborn deaths were reported in the first family but the second family had no history of neonatal purpura fulminans and infant death. Thrombotic symptoms developed mainly in their early twenties, consisting chiefly of recurrent superficial and deep iliofemoral vein thromboses and pulmonary emboli. Other clinical features included generalized peritonitis due to massive mesenteric vein thrombosis, thrombosis of the cavernus sinus, renal vein thrombosis and priapism. In the second family, five members (all aged approximately 40 years) died of intravascular abdominal thrombosis. Massive thromboembolic episodes were associated with a compensated disseminated intravascular coagulation syndrome as evidenced by high concentrations of D-dimer (mean levels 5000 ng/ml plasma) and by a moderate reduction in platelet count and fibrinogen concentrations. D-dimer levels in noncrisis periods were also raised above normal (mean levels 400 ng/ml). The thrombotic problems of these patients were controlled satisfactorily by long-term administration of low molecular weight heparin alone or in combination with low dose warfarin.
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PMID:Congenital severe protein C deficiency in adults. 254 23

Inherited resistance to activated protein C (APC) is a frequent cause of familial thrombosis. It is associated with a factor V gene point mutation replacing arginine506 in the APC-cleavage site with a glutamine. Thrombotic events are rare during childhood even in patients with homozygous APC-resistance. We now wish to report on a case of severe venous thrombosis, in a 10-year-old boy. He was found to have pronounced APC-resistance due to homozygous factor V gene mutation in combination with inherited type I protein S deficiency. The two traits were independently inherited in the family. The APC-resistance was partially corrected by adding factor V, whereas added protein S was without effect. This is the first reported case of homozygous APC-resistance combined with another inherited prothrombotic disorder. It illustrates how multiple genetic defects may provoke thrombosis at young age and emphasizes the need of complete evaluation of thrombotic patients in order to determine whether multiple risk factors exist.
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PMID:Homozygous APC-resistance combined with inherited type I protein S deficiency in a young boy with severe thrombotic disease. 748 96

Thrombotic events have been reported in acute lymphoblastic leukaemia patients, especially during or after L-asparaginase administration. A so-called L-asparaginase associated coagulopathy has been well recognized, being characterized by a hypercoagulable state (decrease of antithrombin III, plasminogen, protein C, protein S and increase of prothrombin fragment F1 + 2, thrombin-antithrombin complexes and fibrinopeptide A). The aim of this study was to determine whether the supplementation of antithrombin III (AT-III) concentrates could improve the L-asparaginase associated coagulopathy, thereby blocking the activation of the haemostatic system. In 25 adult patients with acute lymphoblastic leukaemia (M 19, F6, mean age 34 years) antithrombin III (AT-III) concentrates were administered at daily doses of 50 U/kg for 10 consecutive days from the beginning of L-asparaginase therapy (6,000 U/m2/day s.c. for 7 days), given according to the GIMEMA ALL 0288 trial. A marked increase of antithrombin III was recorded on days IV-VIII-XI (P < 0.001). No changes in protein C, protein S, plasminogen, alpha 2-antiplasmin, factor VII and platelet count were observed and there was no increase in markers of hypercoagulability. There was no evidence of disseminated intravascular coagulation. In conclusion, AT-III concentrate supplementation during L-asparaginase therapy, by the achievement of high levels of antithrombin III, is associated with a lack of activation of the haemostatic system and appears to overcome the complex coagulopathy associated with L-asparaginase.
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PMID:Antithrombin III infusion suppresses the hypercoagulable state in adult acute lymphoblastic leukaemia patients treated with a low dose of Escherichia coli L-asparaginase. A GIMEMA study. 751 43

In the present study, the prevalence of thromboembolic events in patients suffering from type I plasminogen deficiency was evaluated. One hundred and twelve affected subjects belonging to twenty-eight kindreds were gathered from the literature and from personal observations. The incidence of thrombosis found in this group was compared with those seen in: a) 86 unaffected family members; b) 100 hospitalized patients; c) 100 outpatient clinic patients. In the latter two groups, congenital clotting disorders were excluded. Thrombotic manifestations were found in 25.8% of patients with plasminogen deficiency, a figure which was statistically different from those found in unaffected family members (1.16%, p < 0.001), hospitalized patients (3%, p < 0.001) and outpatient clinic patients (5%, p < 0.001). In twenty-four kindreds with hypoplasminogenemia, data concerning the actuarial ages at first thrombotic event were available for construction of thrombosis-free survival curves by the Cutler-Ederer method. The difference between the two curves, corresponding to affected and unaffected family members respectively, were statistically significant (p < 0.01). In conclusion, although the incidence of thromboembolic events in type I plasminogen deficiency is certainly lower than that described in other congenital clotting disorders such as AT III, protein C and protein S, patients with hypoplasminogenemia should be considered at risk for thrombosis, particularly when triggering factors are present.
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PMID:Symptomatic versus asymptomatic patients in congenital hypoplasminogenemia: a statistical analysis. 789 Feb 63

The relevance of heterozygosity for hereditary protein C deficiency as a risk factor for venous thrombosis has been disputed because heterozygotes without symptoms have been identified among blood donors and relatives of homozygotes. As a result, clinicians do not know whether to offer prophylaxis or not. We have compared thrombosis-free survival in 161 heterozygous and normal members of the families of 24 heterozygotes for protein C deficiency referred from several centres in the Netherlands and with a history of symptoms. We studied the influence of heterozygosity and of putative additional risk factors on the occurrence of thrombotic events noted when a medical history was taken. Protein C activities were measured but a diagnosis of heterozygosity was based on the presence of the specific mutation in one of the protein C genes identified in the proband of the family. We found a significant difference in the thrombosis-free survival of the 77 heterozygotes and 84 normals: by age 45, 50% of heterozygotes and 10% of normal relatives can be expected to have had a manifestation of venous thromboembolism. The presence of such a mutation was clearly associated with an increased risk of venous thrombotic events. Thrombotic events occurred more often in years in which the patient had been immobile for more than a week or had had surgery. Other putative risk factors showed no significant effect in the incidence of thrombotic events. About 50% of all first episodes and 65% of recurrences of venous thromboembolism in the heterozygotes were spontaneous--ie, there was no predisposing event such as surgery or pregnancy. There was no increased risk for arterial occlusions in heterozygotes. We conclude that members of the family of a symptomatic heterozygote proband who are heterozygous for the mutation in the protein C gene have an increased risk of venous thrombotic events compared with their normal family members. For such individuals prophylactic anticoagulation should be considered; the decision will need to be taken on an individual basis.
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PMID:Increased risk of venous thrombosis in carriers of hereditary protein C deficiency defect. 809 45

An Italian family with a dysfunctional protein C (type II deficiency) tentatively designated Protein C Padua has been investigated. Five family members had this defect. Thrombotic manifestations occurred in the propositus, his sister, and his 87-year-old mother, who suffered from a transitory ischemic attack (TIA). All other deficient patients were asymptomatic. The abnormality was consistent with normal protein C (PC) antigen level but reduced both anticoagulant and amidolytic activities after PC activation by Protac. When thrombin was used as activator, PC activity level was also reduced. The abnormal PC molecule seemed to have a defect involving the activation region or the active site mechanism (reduced activity level regardless of the PC activators and the methods used in the functional assays). The electrophoretic mobility of the dysfunctional protein, assayed by crossed-immunoelectrophoresis (CIE), was normal in presence of both Na citrate and calcium lactate. The kinetics of antigen-antibody complex formation between the abnormal PC and anti-PC polyclonal antibody was investigated by means of a laser nephelometer and a peculiar pattern was found in the affected patients suggesting a possible anomalous interaction between the antibody and the abnormal protein.
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PMID:A family with an abnormal protein C and a thrombotic tendency. 833 96

Reversibility in vivo of acute platelet thrombosis in response to specific anticoagulants is analyzed with thrombi that develop in segments (1 cm) of porcine carotid arteries externally crushed with a hemostat. Most thrombi fill the lumens of the injured segments (ca. 1 cm x 3 mm, 1 x w) within 30 min and comprise masses of platelets interpenetrated with neutrophil-lined seepage channels of blood. Continuous quantitative assay of thrombus mass is provided by a gamma detector placed over the injured segments to collect counts from 111In-labeled platelets. Thrombi established 30 min after injury, otherwise stable for 6 h, clear during 30-60 min of continuous infusion of either hirudin, tick anticoagulant or activated porcine protein C, or intermittent activation of endogenous protein C with a latent thrombin reagent. Anticoagulant dose-dependence of thrombus clearance is established for hirudin between 0.01 and 1.0 mg/kg/min. Thrombi become progressively refractory to hirudin between 0.5 and 6 h after injury. Neither heparin no low-molecular-weight heparin in full (clinical) anticoagulant doses yield significant dethrombosis. It is concluded that, within time limits, controlled thrombin generation in platelet thrombi maintains platelet cohesion without catalyzing irreversible platelet aggregation or clotting of fibrinogen.
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PMID:Reversibility of platelet thrombosis in vivo. Quantitative analysis in porcine carotid arteries. 897 39


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