摘要:

Tissue factor pathway inhibitor (TFPI), a Kunitz-type protease inhibitor with three tandem inhibitory domains (K1, K2 and K3), inhibits the initial reactions of the extrinsic blood coagulation pathway through its K1 and K2 domains. We prepared and characterized a monoclonal antibody (Mab8–1) against TFPI-factor Xa (TFPI-Xa) complex. The reactivities of Mab8–1 toward TFPI-Xa complex, TFPI without C-terminal (TFPI-C)-Xa complex, K1K2-Xa complex and K2K3-Xa complex were examined using a surface plasmon resonance analysis (Biacore®). The Biacore system allowed a quantitative analysis of antibody-antigen interaction, in real time, from which the association and dissociation rate constants could readily be obtained. The bindings of Mab8–1 to TFPI-Xa complex, TFPI-C-Xa complex and K2K3-Xa complex were each concentration-dependent. However, no binding of Mab8–1 to the K1K2-Xa complex was observed. The binding of Mab8–1 to TFPI or Xa was also not observed. These results suggested that the epitope for Mab8–1 was exposed in the K3 domain of TFPI, which was generated by the conformational change after the formation of TFPI-Xa complex. We then developed an enzyme-linked immunosorbent assay method specific for TFPI-Xa complex using Mab8–1, and we used this assay to measure plasma levels of TFPI-Xa. The normal range assessed from analyses of plasma from 30 normal healthy volunteers was 17.7–66.7 with a mean of 35.5 ± 11.7 pmol/1. In order to asses the clinical implication of TFPI-Xa complex in the plasma of patients with thrombotic disorders, plasma concentrations were measured in 37 patients with disseminated intravascular coagulation (DIC) caused by a variety of underlying diseases. The TFPI-Xa antigen levels were significantly higher in the patients with DIC (51.9 ± 21.6 pmol/1) and the 36 patients with pre-DIC (55.1 ± 20.2 pmol/1) than in the 137 non-DIC patients (37.9 ± 13.1 pmol/1). In the patients with DIC or pre-DIC, there was no significant correlation between TFPI-Xa complex and the elevated levels of thrombin-antithrombin complex, pIasmin-α2 plasmin inhibitor complex, D-dimer, soluble fibrin monomer, soluble thrombomodulin or tissue factor. These data indicate that the plasma level of TFPI-Xa seems to be a novel independent molecular marker of DIC and pre-DIC.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

In order to determine whether prednisolone has a protective effect against the development of disseminated intravascular coagulation (DIC), we measured the effect of prednisolone on changes in hemostatic parameters and plasma levels of inflammatory cytokines in endotoxin-treated rats. Decreases in platelet count and fibrinogen levels, prolongation of prothrombin time, and increases in the plasma fibrin degradation products and levels of thrombin-antithrombin III (TAT) complex following the administration of endotoxin, all of which are associated with DIC, were significantly suppressed by the administration of prednisolone. Heparin administration significantly suppressed changes in all these parameters except for the decrease in platelet count. The combination of prednisolone and heparin was more effective than either treatment alone. In order to determine whether these effects of prednisolone are correlated with the suppression of inflammatory cytokine production, we examined the relationship between changes in plasma levels of cytokine, the hemostatic parameters listed above, and mortality using a number of intervention regimens designed to alter events of the experimentally induced DIC. Changes in hemostatic parameters associated with DIC following 30 mg/kg per 4 h of endotoxin infusion were significantly suppressed by treatment with 1 mg/kg prednisolone 30 min before beginning endotoxin infusion, followed by administration of 250 U/kg heparin 2 h after the start of endotoxin infusion (prednisolone-endotoxin-heparin regimen). The heparin and prednisolone were administrated subcutaneously. The administration of prednisolone and heparin in the reverse order (i.e. heparin first and prednisolone second: heparin-endotoxin-prednisolone regimen) also suppressed changes in hemostatic parameters, albeit to a smaller degree. Cytokine production was also significantly suppressed by the first treatment, but was not affected by the regimen in which heparin was administered first. Administration of prednisolone alone or heparin alone 30 min before endotoxin significantly reduced the number of renal glomeruli with fibrin thrombi. Plasma levels of creatinine and alanine transferase were reduced only by prednisolone. Increased plasma levels of interleukin-1β, tissue necrosis factor-α and interleukin-6 were suppressed by prednisolone but not by heparin, and there were significant correlations between plasma levels of TAT and cytokines. Prednisolone was more effective than heparin in reducing mortality at 24 h after 100 mg/kg over 4 h of endotoxin infusion (four of 20 versus 15 of 20 deaths for prednisolone and heparin, respectively). These findings suggest that prednisolone inhibits the development of endotoxin-induced DIC and reduces mortality by a different mechanism than heparin, possibly through suppressing the production of inflammatory cytokines. Prednisolone may be efficacious in preventing DIC and multiple organ dysfunction caused by endotoxin.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The aim of the present study was to evaluate metabolic, coagulation and fibrinolytic parameters in 45 patients [31 men, 14 women, aged 56.5 ± 3.5 years (mean ± SD)] who had suffered myocardial infarction more than 6 months earlier, with or without carotid atherosclerotic lesions. After the extracranial carotid arteries had been evaluated using a B-mode Duplex scanning system, patients were subdivided into two groups: group 1 (n= 20) with carotid plaques or measurable intima-media thickness; and group 2 (n= 25) without carotid plaques or measurable intima-media thickness. Twenty-two age- and sex-matched subjects were recruited as controls (group 3). Groups 1 and 2 displayed significantly higher levels of total cholesterol, apolipoprotein B, human autoantibodies against oxidised low-density lipoprotein and the c fraction of the third component system, and significantly lower levels of high-density lipoprotein cholesterol and apolipoprotein Al than group 3. However, serum levels of triglyceride and lipoprotein (a) were significantly higher in group 1 than in the control group. Moreover, groups 1 and 2 displayed significantly higher levels of factor VII, fibrinogen, fragment 1+2, thrombin-antithrombin complex and plasminogen activator inhibitor after venous occlusion, and significantly lower levels of tissue-type plasminogen activator after venous occlusion than group 3. Significantly higher levels of tissue-type plasminogen activator and plasminogen activator inhibitor before venous occlusion were observed in groups 1 and 2 and significantly lower levels of antithrombin III, protein C and protein S were observed in group 1 compared with the controls. Patients were also analysed according to levels of lipoprotein (a). The lowest levels of tissue-type plasminogen activator after venous occlusion and the highest levels fragment 1 + 2, the c fraction of the third component system, and plasminogen activator inhibitor after venous occlusion were observed in patients with the highest levels of lipoprotein (a). Our data demonstrate an activation of coagulation and deficient fibrinolysis in survivors of myocardial infarction, particularly in those with associated carotid atherosclerotic lesions. We speculate that this thrombophilic state may play a key role in the pathogenesis of atherosclerotic vascular disease and thromboembolic complications.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Low-density lipoprotein (LDL) adsorption using a dextran sulfate cellulose (DSC) column is commonly performed for extracorporeal removal of LDL in hypercholesterolemic patients with peripheral arterial obstructive disease. We investigated whether the use of heparin or nafamostat mesilate as anticoagulants in a single LDL apheresis produced different clinical effects, or brought about the production of bradykinin and endogenous nitric oxide (NO) in these patients. LDL apheresis was performed in ten patients with peripheral arterial obstructive disease. We measured plasma levels of bradykinin, NO and nitrosylhemoglobin as well as skin temperature. Plasma levels of bradykinin increased 12-fold during LDL apheresis with heparin, but did not increase during LDL apheresis with nafamostat mesilate. LDL adsorption resulted in an immediate rise in skin temperatures (1–2°C) of the lower ischemic legs irrespective of the type of anticoagulant used, and this persisted after the end of LDL apheresis for up to 60 min. There was a progressive and significant increase in plasma NO after the commencement of single LDL apheresis in both groups (heparin group: 64.0 ± 17.3μmol/1 at baseline, 73.3 ± 15.2 μ/mol/1 60 min after apheresis,P< 0.005; nafamostat mesilate group: 65.0 ± 18.8 μ/mol/1 at baseline, 75.5 ± 17.5 μmol/1 60 min after apheresis,P< 0.001). On the other hand, levels of nitrosylhemoglobin increased significantly after 1000 ml of plasma treatment but the level decreased thereafter, although it was significantly higher than baseline 60 min after LDL apheresis. Our results suggest that a single LDL apheresis enhanced peripheral microcirculation, probably as a result of increased production of NO, irrespective of changes in bradykinin release.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Intravenous acetylsalicylic acid (ASA) and magnesium (Mg) both possess antiplatelet properties and are thus potential inhibitors of the formation of arterial thrombi. Their effect on the dynamic aspects of arterial thrombus formation was investigated following intravenous administration of both substances alone and in combination. A blinded, placebo-controlled, in-vivo study was performed in 71 rats. Thrombus formation was induced by a standardized arteriotomy in the right femoral artery with inversion of the vessel wall during subsequent closure. Thrombus formation was recorded on video tapes and analysed off-line for 30 min. Animals were randomly assigned to one of four groups: 20 mg bolus of ASA followed by 0.3 mmol/h Mg (ASA/Mg group); NaCl followed by 0.3 mmol/h Mg (Mg group); 20 mg bolus of ASA followed by NaCl (ASA group); or NaCl throughout the experiment (control group). In the ASA-treated groups, serum levels of thromboxane B2 were reduced significantly, and the Mg-treated groups reached a serum level of Mg just above 2.0 mmol/1. No significant differences were observed in initial or maximum thrombus area or in mean thrombus area during the study period. In the ASA/Mg group, a trend towards reduced thrombus formation was observed (P= 0.06). In the same group, seven of 22 animals developed an occlusive thrombus (P< 0.01), an unexpected adverse event possibly related to the combined administration of ASA and Mg.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

A method for detecting activated protein C (APC)-resistant factor V, especially factor V Leiden, is described, which uses reagents containing two unfractionated snake venoms. The procedure can be used for testing plasma samples from patients receiving oral anticoagulant therapy, heparin therapy and patients with lupus anticoagulant, and does not require the use of factor-V-deficient plasma. The sample plasma is first incubated with dilute venom fromAgkistrodon contortrix contortrix(Southern Copperhead) which activates the endogenous protein C and then a dilute Russell's viper venom time test is performed. In individuals with APC-resistant factor V, especially factor V Leiden, a marginal prolongation of dilute Russell's viper venom time was noted [1.14 ± 0.14 s (n= 16)]. Non-carriers were easily discriminated in each patient group, with a prolongation of 2.69 ± 0.30 s for normal blood donors (n= 127), 2.61 ± 0.38 s for patients taking oral anticoagulants (n= 102), 2.41 ± 0.45 s for patients taking heparin (n= 96), and 2.38 ± 0.41 s for patients with lupus anticoagulant (n= 22). Patients taking oral anticoagulants with moderate prolongation (between 1.5− and 2.0-fold) may have low levels of functional protein C and this might additionally indicate a subgroup of such patients at higher than normal thrombotic risk.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Low-molecular-weight heparins, when used in surgical patients for thromboprophylaxis, may be used concurrently with ketorolac, a non-steroidal anti-inflammatory drug that is used for analgesia. Because these two agents can influence the haemostatic system, it is important to identify any such effect. The haemostatic interaction between dalteparin and ketorolac was assessed in a double-blind, placebo-controlled, randomized, crossover study of healthy male volunteers each given all four combinations of ketorolac/ placebo and dalteparin/placebo. The effect of ketorolac and dalteparin on haemostasis was assessed by measuring in-vitro platelet aggregation, anti-factor-Xa, activated partial thromboplastin times and skin bleeding time. The results were analysed for evidence of an interaction between ketorolac and dalteparin. Ketorolac inhibited platelet aggregation in whole blood and platelet-rich plasma. The administration of dalteparin led to a significant increase in levels of anti-factor-Xa and a significant prolongation in the activated partial thromboplastin time, although it remained within the range of the normal population. There was no evidence of any interaction between ketorolac and dalteparin with regard to platelet aggregation, anti-factor-Xa activity or activated partial thromboplastin time. The administration of ketorolac significantly prolonged the skin bleeding time. There was a significant interaction between ketorolac and dalteparin to prolong the bleeding time, although dalteparin alone had no effect on bleeding time. There was an interaction between ketorolac and dalteparin, which affected bleeding times. Such an interaction raises the possibility of haemorrhagic complications developing perioperatively when these agents are used concomitantly. Further studies are required to examine the clinical importance of this interaction.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Increased levels of the endothelial markers von Willebrand factor and soluble thrombomodulin have been identified as predictors of the development of adverse cardiovascular events. The purpose of this study was to determine which of these markers is the best predictor of such events. Both markers were measured using enzyme-linked immunosorbent assays in 111 subjects at high risk of cardiovascular disease (50 with peripheral atherosclerosis and 66 who had suffered myocardial infarction). After a mean of 46 months, a follow-up investigation was performed and cardiovascular end-points (myocardial infarction, stroke, measured progression of peripheral atherosclerosis, arterial surgery, etc.) were noted. Multivariate analysis revealed that both markers were independent predictors among the 54 subjects who suffered any one of the cardiovascular end-points (P< 0.01). However, only an increased level of von Willebrand factor predicted the outcome among the 39 subjects who suffered a myocardial infarction, stroke or arterial surgery (P< 0.05). We conclude that von Willebrand factor is a marginally better predictor of cardiovascular events than soluble thrombomodulin.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Endothelial cell injury and platelet activation are considered primary events in the pathogenesis of coronary artery disease (CAD) and are marked by plasma concentrations of von Willebrand factor (vWF) and soluble thrombomodulin, and by soluble P-selectin, respectively. Because both endothelial cells and platelets interact with contrast media, we aimed to detect immediate and 24-h changes in these markers following coronary angiography in patients with and without CAD. Sixteen patients with angiographically proven CAD and 14 patients without significant coronary stenosis were investigated. Blood samples were obtained from an antecubital vein before and 24 h after cardiac catheterization, and from the coronary sinus before and immediately after angiography. Concentrations of the markers were determined using enzyme-linked immunosorbent assays. In the coronary sinus samples, the only significant finding was an increase in levels of soluble P-selectin in the patients with CAD (P< 0.038). In the post-catheterization peripheral blood samples, concentrations of soluble P-selectin (P= 0.004), vWF (P= 0.0007) and soluble thrombomodulin (P= 0.0013) were all increased in patients with CAD. In contrast, patients without CAD demonstrated increased levels of vWF only (P= 0.0015) in peripheral blood samples obtained 24 h after angiography. We conclude that both immediate and 24-h changes take place in endothelial cells and platelet markers in response to cardiac catheterization, and that these changes are different in patients with angiographically proven CAD and in patients free of disease. These differences may reflect alterations in endothelial cell or platelet reactivity in patients with CAD.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Prothrombin gene G20210A polymorphism has been recently identified as a cause of venous thrombosis. However the association between this mutation and arterial thrombosis remains uncertain. Some authors have suggested that the polymorphism in the 3′ region of the prothrombin gene may precipitate cerebral arterial thrombosis in young patients with prothrombotic conditions. We report a case of post-traumatic basilar artery thrombosis in a young patient carrier of the prothrombin gene G20210A polymorphism. Thirty-six hours after sustaining a head injury in the occipital region, a young man developed vomiting, headache, dizziness and truncal ataxia, without signs of focal impairment. Magnetic resonance imaging and selective angiography carried out 2 days later showed an obstruction of the basilar artery, with infarction of the right cerebellar region. A transthoracic echocardiogram showed a patent foramen ovale with little left-to-right shunt and an aneurysm of the interatrial septum. Blood examination showed a heterozygous status for prothrombin gene G20210A polymorphism. We conclude that this prothrombin gene mutation and the coexisting particular head injury and interatrial septal aneurysm could have contributed simultaneously to the development of basilar artery occlusion and cerebellar infarction. We suggest that in selected cases of cerebellar ischemia a prothrombin gene G20210A polymorphism should be considered.

ISSN:0957-5235    

出版商:OVID    

年代:1999

数据来源: OVID