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)

The chronic and immediate post-exercise responses in the hemostatic and fibrinolytic systems have been shown to be variable and reflect differing adaptations with ageing and responses to exercise protocols. This study investigated the effects of acute and exhaustive exercise on the amplitude and duration of hemostatic and fibrinolytic responses in young adolescent males. The sample comprised 10 sedentary boys (13.2+/-0.5 years, 55.8+/-11.3kg, 165.7+/-7.4cm), who had not exercised or received any medication for at least 2 weeks before the experiments. The subjects performed exhaustive stepping exercise, consisting of 1s up and down cycles to fatigue. When the subjects were unable to maintain the required stepping rhythm, they were given a 30s recovery period. Following each 30s recovery participants recommenced the stepping cadence until fatigue prevented them continuing. Venous blood samples were drawn before and immediately, 1 and 24h after exercise to assess the following coagulation and fibrinolytic parameters: Platelet counts, activated partial thromboplastin time (aPTT), prothrombin time (PT), coagulation factor VIII (FVIII:C), von Willebrand factor (vWF), fibrinogen concentration, thrombin-antithrombin complex (TAT), D-dimer, plasminogen activator inhibitor (PAI-1), and tissue-type plasminogen activator (t-PA). Immediately following exercise, platelet counts, aPTT, FVIII, vWF and t-PA were significantly elevated in contrast to PAI-1, which decreased significantly until 1h after exercise. FVIII and platelet counts were elevated at 1 and 24h after exercise, respectively. Only the parameters FVIII and PAI-1 did not return to baseline values during the first hour after physical exercise. When compared to adults the results revealed different rates and ranges of coagulation and fibrinolysis parameters being activated by exhaustive exercise in this group of adolescents.
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PMID:Hemostatic response to acute physical exercise in healthy adolescents. 1684 9

Substantial epidemiologic, laboratory, pathologic and clinical evidence supports the historic association between activation of blood coagulation and progression of cancer. The increased risk for venous thromboembolism(VTE) in cancer has been considered an epiphenomenon. However, recent studies from several laboratories have linked more closely malignanttransformation (oncogenesis), tumor angiogenesis and metastasis to the generation of clotting intermediates(e.g. tissue factor [TF], factor Xa and thrombin),clotting or platelet function inhibitors (e.g. COX-2) or fibrinolysis inhibitors (e.g. plasminogen activator inhibitor, type 1 [PAI-1]). Furthermore, TF, Xa and thrombin may induce important tumor cell signaling cascades in a clotting-dependent and/or clotting independent manner (e.g. thru engagement of protease-activated receptors [PARs]). Targeting blood clotting reactions in cancer may provide a unique approach to cancer treatment.
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PMID:Mechanisms of cancer-induced thrombosis in cancer. 1685 54

Plasminogen activator inhibitor 1 is known to be elevated in patients with hepatic VOD after intensive chemotherapy. To re-establish endogenous fibrinolysis and to inhibit thrombin formation, we used non-APC (zymogen) to normalize PAI-1 levels. As a consequence of thrombin formation inhibition and the consecutive inhibition of the coagulation cascade, this treatment is expected to reduce the elevated D-dimer level. Six pediatric stem cell recipients with moderate or severe VOD after busulfan or total body irradiation conditioning regimen are reported here who were therapy-refractory to defibrotide or rt-PA therapy. All patients had low levels of PC activity (16-39%). The administration of PC (60-240 IU/kg) led to a rapid and sustained rise in PC activity (target level >80%) with near normalization of prothrombin and partial thromboplastin time in all patients. Elevated PAI-1 levels declined. Five of the six patients showed a good clinical response with prompt resolution of clinical, sonographic, and laboratory signs of hepatic blood flow obstruction, while one patient with severe VOD, as well as concomitant liver GVHD and CMV disease, had a slow but detectable response to PC therapy. All patients survived.
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PMID:Favorable response of pediatric stem cell recipients to human protein C concentrate substitution for veno-occlusive disease. 1723 23

Chronic liver disease is accompanied by derangement of hepatocyte function including the synthesis of haemostastic factors. It is, however, not known whether the improvement in liver functions as a result of interferon (IFN)-alpha therapy would be reflected in the plasma levels of these factors. To evaluate the effect of IFN-alpha therapy on the plasma levels of natural anticoagulants and on the fibrinolytic parameters, in patients with chronic viral hepatitis. Twenty one patients with chronic viral hepatitis (B and C) were treated with IFN-alpha, and were studied before commencement of therapy (first sample) 3 (second sample) and 6 months (third sample) later. The coagulation screening tests: activated partial thromboplastin time, prothrombin time, thrombin time, reptilase time and plasma fibrinogen and the natural anticoagulants: antithrombin, Protein C and free and total protein S as well as fibrinolytic parameters (tissue type plasminogen activator, plasminogen activator inhibitor type-1 and plasminogen) were measured. An increase in the levels of total protein S at 3 and 6 months after the commencement of IFN therapy was noted but the increase was statistically significant in the latter period. Reptilase time was prolonged in the first (pretreatment) and in the second samples and then began to decrease in the third sample but remained higher than the pretreatment level. Fibrinogen level increased in the second and third samples. No remarkable changes were noted in other haemostatic parameters. Total protein S level is a good marker of response to IFN therapy. IFN therapy does not affect other natural anticoagulants or fibrinolytic parameters. More detailed studies need to be done to confirm these findings.
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PMID:Natural anticoagulants and fibrinolytic activity following interferon therapy in chronic viral hepatitis. 1846 46

The two components of biological variability are interindividual variability, which is the variability due to the heterogeneity of physiologic influences among subjects, and intraindividual variability, which is due to the variability in the same individual over time. Analysis of biological variation is crucial for estimating the critical difference, which corresponds with a threshold suggestive of a statistically significant difference between two consecutive results of a laboratory parameter in the same subject and is therefore unlikely attributable to casual (random) oscillation of values. Studies on biological variation of tests of hemostasis are outdated, and the published results should be confirmed by using modern, fully automated methods. Biological variation for coagulation screening tests (prothrombin time and activated partial thromboplastin time) is low and comparable with the values registered for hematologic parameters. However, the index of individuality (ratio between intraindividual and interindividual variability) suggests that the usual preoperative screening for coagulation disorders is influenced by the between-subjects variability. Thrombin time is very constant within and between subjects. Proteins such as fibrinogen, clotting factors, and antithrombin show a low biological variability. In contrast, fibrinolytic parameters, such as plasminogen activator inhibitor 1 and fibrinopeptide A, show very high variability, and their interpretation in the clinical setting must take this into consideration.
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PMID:Biological variation in tests of hemostasis. 1908 63

Both women and men with cancer are at increased risk for developing venous thromboembolism (VTE), a propensity that has been known for many years. Until recently it was assumed, however, that the association between cancer and thrombosis is an epiphenomenon - not causally related to the transforming malignant events. The pathophysiology of thrombosis in patients with cancer is complex involving multiple tumor-related and host-related factors. Several recent studies have provided strong evidence that activation of blood coagulation, perhaps most often mediated by tissue factor (TF)-rich microparticles (MPs), is linked directly to oncogene-induced malignant transformation. In addition, the development of VTE, either before or concurrent with the diagnosis of cancer, appears to predict an aggressive behavior of a tumor, and correlates with increased tumor angiogenesis and early onset of distant metastasis. The regulation of expression of TF in tumor cells is controlled at the molecular level by several oncogenes, as appears to be true for cyclooxygenase-2 (COX-2), an important regulator of platelet function and plasminogen activator inhibitor type 1 (PAI-1), an inhibitor of fibrinolysis. In addition, engagement of protease-activated receptors (PARs) by the TF-factor VIIa complex, factor Xa and/or thrombin, have now been shown to be important for tumor growth, angiogenesis and metastasis. Targeting blood clotting reactions in cancer, therefore, may provide a unique approach to cancer treatment.
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PMID:Cancer and thrombosis in women - molecular mechanisms. 1921 69

The two components of biological variability are interindividual variability, which is the variability due to the heterogeneity of physiologic influences among subjects, and intraindividual variability, which is due to the variability in the same individual over time. Analysis of biological variation is crucial for estimating the critical difference, which corresponds with a threshold suggestive of a statistically significant difference between two consecutive results of a laboratory parameter in the same subject and is therefore unlikely attributable to casual (random) oscillation of values. Studies on biological variation of tests of hemostasis are outdated, and the published results should be confirmed by using modern, fully automated methods. Biological variation for coagulation screening tests (prothrombin time and activated partial thromboplastin time) is low and comparable with the values registered for hematologic parameters. However, the index of individuality (ratio between intraindividual and interindividual variability) suggests that the usual preoperative screening for coagulation disorders is influenced by the between-subjects variability. Thrombin time is very constant within and between subjects. Proteins such as fibrinogen, clotting factors, and antithrombin show a low biological variability. In contrast, fibrinolytic parameters, such as plasminogen activator inhibitor 1 and fibrinopeptide A, show very high variability, and their interpretation in the clinical setting must take this into consideration.
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PMID:Biological variation in tests of hemostasis. 1930

Glomerular and microvascular thrombosis due to the activation of inflammation and coagulation pathway contribute to the occurrence of acute renal failure in sepsis. The protease-activated receptors (PARs) have been shown to play an important role in the interplay between inflammation and coagulation. We hypothesized that PAR-2 blocking would improve glomerular and vascular thrombosis by attenuating inflammation and coagulation, leading to the prevention of acute renal failure, and assessed the effects of the PAR-2 blocking peptide (PAR-2 BP) in a rat model of LPS-induced acute renal failure. Levels of TNF-alpha were significantly expressed 1 h after LPS administration, followed by 1) an increase in levels of tissue factor, factor VIIa, factor Xa, thrombin and plasminogen activator inhibitor 1; 2) unchanged levels of tissue factor pathway inhibitor; and 3) subsequent deposition of fibrin in kidney tissues, which led to the elevation of creatinine and blood urea nitrogen. Time-dependent PAR-2 expression was observed at both the gene and protein levels. Immunoreactivities of PAR-2 and fibrin were observed in the glomerulus and small arteries. Protease-activated receptor blocking peptide suppressed TNF-alpha elevation and attenuated activation of the coagulation, thus leading to a decrease in fibrin formation and its deposition in the glomerulus. However, the levels of creatinine and blood urea nitrogen remained unchanged. These results show that PAR-2 plays a key role in the inflammatory and coagulation process of LPS-induced renal failure; however, PAR-2 inhibition alone does not affect improvement in the renal function.
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PMID:Protease-activated receptor 2 blocking peptide counteracts endotoxin-induced inflammation and coagulation and ameliorates renal fibrin deposition in a rat model of acute renal failure. 2016 Jun 13

Coagulation abnormalities are common in severe pneumonia and sepsis, yet little is known about the presence of coagulopathy or its significance in patients with lesser illness severity. We examined coagulation abnormalities in 939 subjects hospitalized with community-acquired pneumonia (CAP) in 28 US hospitals, hypothesizing that abnormalities would increase with illness severity and poor outcomes. We measured plasma coagulation markers (D-dimer, plasminogen activator inhibitor [PAI], antithrombin, factor IX, and thrombin-antithrombin complex [TAT]) at the time of patient presentation to the emergency department and daily during the first wk of hospitalization. Day-1 clinical laboratory test results for international normalized ratio, activated partial thromboplastin time, and platelet count were recorded from the medical record. In our cohort, 32.5% of patients developed severe sepsis and 11.1% died by d 90. Day-1 coagulation abnormalities were common, especially for D-dimer (80.6%) and TAT (36.0%), and increased with illness severity and poor outcomes. However, abnormalities also occurred in those patients who never developed organ dysfunction and differences between groups were modest. The proportion of patients with abnormalities changed over time, yet the magnitude of change was small and not always in the direction of normality. Many patients remaining in the hospital continued to manifest coagulation abnormalities on d 7, especially for D-dimer (86.5%) and TAT (36.9%). In conclusion, coagulation abnormalities were common and persistent in CAP patients, even among the least ill. These findings underscore the complexity of the coagulation response to infection and may offer insights into coagulation-based therapeutics in clinical sepsis trials.
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PMID:Prevalence and significance of coagulation abnormalities in community-acquired pneumonia. 1975 44

Vascular complications are a common factor determining morbidity and mortality of diabetic patients. In vitro studies have revealed that gliclazide has antiplatelet activities. To clinically assess this action, we measured the effects of gliclazide on platelet activities and abnormal fibrinolysis in patients with type 2 diabetes mellitus. We studied 14 patients aged 38 to 72 years (9 men and 5 women) with type 2 diabetes mellitus who have been treated with glibenclamide in our hospital for more than 6 months. We switched from glibenclamide to gliclazide using the average ratio of the respective doses, 2.5 vs 40 mg. We titrated the dose of gliclazide to keep the glycemic control at the same level as the previous (glibenclamide) treatment. We measured 10 micromol/L serotonin-induced or 0.5 micromol/L adenosine diphosphate (ADP)-induced platelet aggregate formation by particle counting using light scattering at baseline and up to 6 months after the switch. After switching to gliclazide, platelet aggregate formation induced by serotonin was significantly reduced (P < .05, compared with the levels observed after glibenclamide treatment). The body mass index, fasting plasma glucose, immunoreactive insulin, homeostasis model assessment of insulin resistance, hemoglobin A(1c) (HbA(1c)), total cholesterol, triglycerides, high-density lipoprotein cholesterol, prothrombin time, activated partial thromboplastin time, fibrinogen, thrombin-antithrombin III complex, plasmin-alpha2-plasmin inhibitor complex, and plasma plasminogen activator inhibitor type 1 (PAI-1) were not changed. In the group with improved HbA(1c) (n = 5), ADP-induced platelet aggregate formation and plasma PAI-1 level were significantly reduced (P < .05, compared with the group with aggravated HbA(1c), n = 9). Multiple regression analysis showed that percentage change of ADP-induced platelet aggregate formation (standardized beta = 0.540, P < .05) was independently associated with percentage change of plasma PAI-1 level in addition to percentage change of HbA(1c) (standardized beta = 0.657, P < .05) (R = 0.939, P < .05) after switching to gliclazide. The other independent variants, like the final dose of gliclazide, homeostasis model assessment of insulin resistance, percentage change of prothrombin time, activated partial thromboplastin time, and total cholesterol, were not significantly associated with the percentage change of plasma PAI-1 level. These results indicate that gliclazide inhibits platelet aggregation via the serotonin pathway, independently of the metabolic control per se. Furthermore, in the patients with improved glycemic control, gliclazide could inhibit ADP-induced platelet aggregation and reduce PAI-I level. Taken together, the results show that gliclazide may be more useful for the prevention of diabetic vascular complications than glibenclamide.
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PMID:Effects of gliclazide on platelet aggregation and the plasminogen activator inhibitor type 1 level in patients with type 2 diabetes mellitus. 2007 Sep 90


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