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1.
Jenny Hernestål-Boman Jan-Håkan Jansson Torbjörn K. Nilsson Lars Johansson 《Thrombosis research》2010,125(5):451-456
Introduction
Blood samples in epidemiological studies are often stored for several years and analysed at different occasions. The reagent kits are continually modified for better precision and accuracy. Our hypothesis was that epidemiological studies are affected by long-term storage and/or modifications of reagent kits.Materials and Methods
Plasma samples stored at -80 °C from two populations were used: A case-referent study with samples collected from 1985 to 2000 and analysed 2005 (n = 1598) were used to study influence of long-term storage. A cross-sectional study analysed 1990 (n = 1558) and re-analysed 2001 (n = 78) and 2005 (n = 828) was used to study influence of reagent kit modifications. Fibrinolytic analyses included immunoassays of tPA, PAI-1 and tPA-PAI-1 complex and chromogenic substrate assays of the activities of tPA and PAI-1.Results
Long-term storage for a median time of 11.6 years (range 5 to 20) showed an effect of time on tPA antigen R2 = 0.01, PAI-1 antigen R2 = 0.01 and tPA-PAI-1 complex R2 = 0.02. Modifications in reagent kits affected the levels of fibrinolytic factors; for tPA antigen the slope coefficients were between 0.72 and 0.95 (R2 0.47 - 0.75), whereas tPA activity showed an agreement with slope coefficients 1.06 to 1.09 (R2 0.67 - 0.93).Conclusions
This study showed that long-term storage affects fibrinolytic variables to a negligible extent, but modifications in reagent kits introduced an element of bias. We conclude that analysis of samples on a single occasion is preferable to multiple occasions, as storage has negligible effect. 相似文献2.
Introduction
During exercise, ischemic risk increases, possibly due to changes in coagulation and fibrinolytic activity. Previous research suggests ambient temperature affects resting thrombotic potential, but the effect of heat and cold on hemostasis during exercise is unknown. The purpose of this study was to assess changes in coagulation and fibrinolysis during maximal exercise in hot and cold temperatures, and to compare those responses to exercise under temperate conditions.Materials & Methods
Fifteen healthy men completed maximal exercise tests in hot (30 °C), temperate (20 °C) and cold (5° - 8 °C) temperatures. Blood samples were obtained before and immediately after exercise and analyzed for concentrations of thrombin-antithrombin III (TAT), active tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1). Results were analyzed by ANOVA.Results
A main effect of time was observed for TAT (temperate = 1.71 ± 0.82 - 2.61 ± 0.43 ng/ml, hot = 1.81 ± 0.73 - 2.62 ± 0.67 ng/ml, cold = 2.33 ± 0.65 - 2.89 ± 0.81 ng/ml, PRE to POST, respectively) and tPA activity (temperate = 0.72 ± 0.44 - 2.71 ± 0.55 IU/ml, hot = 0.72 ± 0.38 - 2.64 ± 0.61 IU/ml, cold = 0.86 ± 0.45 - 2.65 ± 0.77 IU/ml, PRE to POST, respectively). A trend was observed for the PAI-1 response to exercise (temperate = 14.5 ± 23.7 - 12.3 ± 20.2 IU/ml, hot = 15.1 ± 26.5 - 10.0 ± 15.1 IU/ml, cold = 10.5 ± 10.4 - 7.9 ± 9.7 IU/ml, PRE to POST, respectively, p = 0.08). TAT concentrations were significantly higher in cold compared to temperate and hot conditions.Conclusion
Coagulation potential is elevated during exposure to cold temperatures. These data suggest that risk of an ischemic event may be elevated in the cold. 相似文献3.
Introduction
Asymmetric dimethylarginine (ADMA) is a potent endogenous inhibitor of nitric oxide (NO) synthase. An increased synthesis and/or a reduced catabolism of ADMA might contribute to the onset and progression of thrombosis. The present study was designed to evaluate the effect of ADMA on fibrinolytic factors in endothelial cells, and to investigate the cellular mechanisms.Materials and Methods
Human umbilical vein endothelial cells (HUVECs) were treated with different concentrations of ADMA for various periods; Then HUVECs were preincubated with NO precursor (L-arginine), MAPK inhibitors, or NF-κB inhibitor (PDTC) before ADMA treatment to repeat the experiment. Protein levels of tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1), and NF-κB activity were measured by ELISA; mRNA levels of tPA and PAI-1 were assayed by qRT-PCR; The activation of MAPK was characterized by western blot analysis.Results
(1) ADMA decreased tPA antigen levels in time- and concentration-dependent manners, with the maximum effect of 30 μmol/L ADMA for 48 h (control 109.01 ± 4.15 ng/ml vs ADMA 86.76 ± 5.95 ng/ml, p < 0.01); (2) 30 μmol/L ADMA elevated antigen levels of PAI-1 in a time-dependent manner, with the maximum effect of 30 μmol/L ADMA for 48 h (control 2721.12 ± 278.02 ng/ml vs ADMA 3435.78 ± 22.33 ng/ml, p < 0.05); (3) ADMA reduced tPA mRNA levels and increased PAI-1 mRNA levels; (4) L-arginine, SB203580 (p38 MAPK inhibitor) and PDTC attenuated the effects of ADMA on tPA and PAI-1 significantly. (5) ADMA induced a rapid phosphorylation of p38 MAPK, and stimulated NF-κB activity greatly.Conclusions
ADMA may accelerate thrombosis development by impairing fibrinolytic activity in vascular via inhibiting nitric oxide production and then activating its downstream p38 MAPK and NF-κB pathways. 相似文献4.
Laing ST Moody MR Kim H Smulevitz B Huang SL Holland CK McPherson DD Klegerman ME 《Thrombosis research》2012,130(4):629-635
Introduction
Ultrasound (US)-enhanced thrombolytic treatment protocols currently in clinical trials for stroke applications involve systemic administration of tissue plasminogen activator (tPA; Alteplase), which carries a risk of adverse bleeding events. The present study aimed to compare the thrombolytic efficacy of a tPA-loaded echogenic liposome (ELIP) formulation with insonification protocols causing rapid fragmentation or acoustically-driven diffusion.Materials and Methods
Thrombi were induced in the abdominal aortas of male New Zealand white rabbits (2-3 kg) using thrombin and a sclerosing agent (sodium ricinoleate) after aortic denudation with a balloon catheter. Thrombolytic and cavitation nucleation agents (200 μg of tPA alone, tPA mixed with 50 μg of a microbubble contrast agent, or tPA-loaded ELIP) were bolus- injected proximal to the clot through a catheter introduced into the abdominal aorta from the carotid artery. Clots were exposed to transabdominal color Doppler US (6 MHz) for 30 minutes at a low mechanical index (MI = 0.2) to induce sustained bubble activity (acoustically-driven diffusion), or for 2 minutes at an MI of 0.4 to cause ELIP fragmentation. Degree of recanalization was determined by Doppler flow measurements distal to the clots.Results
All treatments showed thrombolysis, but tPA-loaded ELIP was the most efficacious regimen. Both US treatment strategies enhanced thrombolytic activity over control conditions.Conclusions
The thrombolytic efficacy of tPA-loaded ELIP is comparable to other clinically described effective treatment protocols, while offering the advantages of US monitoring and enhanced thrombolysis from a site-specific delivery agent. 相似文献5.
Introduction
Factors regulating brain tissue plasminogen activator (tPA) are pertinent for stroke. Recent observations have suggested a role for the phosphodiesterase-4 (PDE4) pathway in stroke pathogenesis, via an uncertain mechanism. We studied PDE4 regulation of tPA expression by human brain microvascular endothelial cells in a variety of conditions, including an in vitro model of ischemia.Materials and Methods
We analyzed tPA antigen and mRNA of human brain microvascular endothelial cells (HBECs) during normoxia and oxygen-glucose deprivation (OGD) following inhibition of PDE4 and PDE4D, using HBEC monocultures and co-cultures with astrocytes and pericytes, and analyzed relevant signal transduction pathways.Results
PDE4 inhibitor rolipram enhanced OGD effects on endothelial tPA release in endothelial monocultures and co-cultures with astrocytes; there was a 54 ± 10% (p < 0.001) reduction of tPA release in astrocyte-endothelial co-cultures under OGD. PDE4D siRNA reduced endothelial tPA mRNA to 40-55% of control (p < 0.05). Use of Epac inducer mimicked, while use of Epac siRNA inhibited, these effects.Conclusions
Inhibition of PDE4 and PDE4D reduced expression of tPA by HBEC via Epac pathway. 相似文献6.
Sakai T Inoue S Takei M Ogawa G Hamazaki Y Ota H Koboyashi Y 《Thrombosis research》2011,127(5):443-449
Introduction
Recent studies have suggested that circulating inflammatory cells augment the growth of thrombus in acute coronary syndrome (ACS). We therefore immunohistochemically analyzed thrombi in aspirates obtained from patients immediately after the onset of ACS.Materials and Methods
Two hundred twenty samples were studied. Total thrombus area, white thrombus area, and red thrombus area were measured. As antibodies in immunohistochemical staining, myeloperoxidase (MPO), CD66b, CD68, p-selectin, tissue factor (TF) and PAI-1were employed respectively.Results
The ratios of areas of red and white thrombi correlated with whole sample areas of enlarged thrombi (r = 0.48, p < 0.001). The immunohistochemical findings revealed granulocytes and macrophages aggregated around p-selectin-positive platelets that shared the boundary between white and red thrombi, a region where MPO and CD66b expression was abundant in neutrophils. The ratios (%) of MPO- and CD66b-positive cells significantly correlated with whole sample areas (r = 0.50; p < 0.001 and r = 0.49; p < 0.001, respectively). Neutrophils and macrophages within thrombi were positive for TF and PAI-1. Along the boundary between red and white thrombi, TF and PAI-1 positivity coincided with MPO-, CD66b- and CD68-positive cells. The ratios of cells positive for both TF and PAI-1 in this area significantly correlated with the whole sample area (r = 0.43, p < 0.001 and r = 0.60, p < 0.001, respectively).Conclusions
These results suggested that enhanced activation of peripheral neutrophils together with increased TF and PAI-1 expression might comprise a considerable portion of thrombus enlargement. 相似文献7.
Introduction
Lower extremity arterial disease (LEAD) is often one of the first signs of a generalized atherosclerotic disease in type 1 and type 2 diabetic subjects.Materials and methods
We studied 143 diabetic subjects at 30-70 years of age, M/F 69/74, 74 with type 1 and 69 with type 2 diabetes, without previously known or suspected lower extremity arterial disease. The relationship between early asymptomatic lower extremity arterial disease and blood levels of HbA1c, lipids and fibrinolysis markers (tPA-activity, tPA mass, PAI-1 activity, tPA-PAI-1 complex) was assessed. In parallel, a group with non-diabetic subjects (n = 80) was studied.Results
35 (24%) diabetic subjects were classified as having sign(s) of LEAD, defined as having at least one reduced peripheral blood pressure measurement, 28% in type 1 vs 20% in type 2 diabetic subjects (p = NS). In univariate logistic regression analyses age, glycemic level (HbA1c), male gender (only in type 1 diabetic subjects), hypertension and tPA activity (only in type 2 diabetic subjects) were positively associated with LEAD. When markers of fibrinolysis were entered into a multivariate model adjusting for age, hypertension, and HbA1c, only tPA activity remained independently associated with LEAD (p = 0.01) and this was also found in type 2 diabetic subjects (p = 0.05). In type 1 diabetic subjects the increase in odds ratio was non-significant.Conclusions
Tissue plasminogen activator (tPA) activity may be an independent and early marker for asymptomatic lower extremity arterial disease in diabetic subjects, particularly in type 2 diabetes. Thus an altered fibrinolytic activity could be an early marker of atherosclerosis development in the lower extremities but the cause-effect relationship remains unclear. 相似文献8.
Laine O Joutsi-Korhonen L Mäkelä S Mikkelsson J Pessi T Tuomisto S Huhtala H Libraty D Vaheri A Karhunen P Mustonen J 《Thrombosis research》2012,129(5):611-615
Introduction
Puumala virus (PUUV) infection is a viral hemorrhagic fever with renal syndrome (HFRS) characterized by thrombocytopenia and acute impairment of renal function. We aimed to assess whether genetic polymorphisms of platelet antigens together with those of von Willebrand factor (VWF) and plasminogen activator inhibitor (PAI-1) correlate with disease severity.Patients and methods172 consecutive hospital-treated patients with serologically confirmed acute PUUV infection were included. Platelet glycoprotein (GP) IIIa T > C (rs5918), GP Ia T > C (rs1126643), GP Ib C > T (rs6065), GP VI T > C (rs1613662), VWF A > G (rs1063856) and PAI-1 A > G (rs2227631) were genotyped. The associations of the rarer alleles with variables reflecting the severity of the disease were analyzed.Results
PAI-1 G-carriers had higher maximum creatinine level compared with the non-carriers (median 213 μmol/l, range 60-1499 μmol/l vs. median 122 μmol/l, range 51-1156 μmol/l, p = 0.01). The GG-genotypes had higher creatinine levels than GA- and AA-genotypes (medians 249 μmol/l, 204 μmol/l and 122 μmol/l, respectively, p = 0.03). Polymorphisms of GP VI and VWF associated with lower creatinine levels during PUUV infection. The minor C-allele of GP Ia associated with lower platelet counts (median 44 × 109/l, range 20-90 × 109/l vs median 64 × 109/l, range 3-238 × 109/l; p = 0.02).Conclusions
Polymorphism of PAI-1, a major regulator of fibrinolysis, has an adverse impact on the outcome of kidney function in PUUV-HFRS. Platelet collagen receptor GP Ia polymorphism associates with lower platelet count. 相似文献9.
Introduction
In vitro studies indicate an anticoagulant effect of 1,25-dihydroxyvitamin D, and sun exposure may lower the risk of thrombotic events. Accordingly, an effect on haemostatic parameters could be expected after supplementation with vitamin D.Materials and Methods
158 obese or overweight subjects were included in a one year intervention study with supplementation with 40.000 IU vitamin D3 per week or placebo. All subjects were given 500 mg calcium daily. Plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator antigen (tPA Ag), and tissue factor-induced thrombin generation over time in plasma assessed by the calibrated automated thrombogram (CAT) method as a parameter of over all thrombotic activity, were measured before and at the end of the study.Results
Mean baseline serum 25(OH)D level was 61.8 nmol/L and increased in the vitamin D group to 145.6 nmol/L at the end of the study. At baseline there was a significant decrease in the CAT variables lag time and time to peak of the thrombogram across increasing serum 25(OH)D quartiles, whereas no significant associations between serum 25(OH)D and PAI-1 or tPA Ag were found. After one year, no significant differences were found between the vitamin D and placebo groups regarding change in any of the haemostatic parameters.Conclusions
The association between lag time and time to peak in the CAT assay and serum 25(OH)D levels could indicate a pro-thrombotic state in subjects with high serum 25(OH)D levels, whereas the lack of effect of high dose vitamin D supplementation questions the causality of this relation. 相似文献10.
Introduction
Oral contraceptives (OC) in the presence of factor V Leiden mutation (FVL) markedly increase the risk of venous thromboembolism (VTE). Little is known about the OC and FVL-related alterations in fibrin clot properties.Subjects and Methods
Plasma fibrin clot permeability (Ks) and efficiency of lysis, reflected by clot lysis time (CLT) and the rate of D-dimer release from clots (D-Drate) induced by recombinant tissue plasminogen activator (tPA) were determined in 25 women with a family history of VTE who were heterozygous for FVL [FVL(+/−) - twice, on third-generation OC and after their discontinuation. Female non-carriers of FVL, matched for demographics, using OC and after their discontinuation served as controls (n = 25). All participants had no personal history of VTE.Results
OC discontinuation in FVL(+/−) women resulted in shortened CLT (− 9%), and increased Ks (+ 4%) and D-Drate (+ 1.4%; all p < 0.01). Alterations in fibrin clot properties were associated with decreased prothrombin fragments 1 + 2 (F1 + 2) (− 8%), plasminogen activator inhibitor-1 (PAI-1) antigen (− 11%), and thrombin activatable fibrinolysis inhibitor (TAFI) activity (− 20%; all p < 0.01). During OC use FVL(+/−) carriers compared with non-carriers had higher platelet count, activity of PAI-1, TAFI, and tPA, as well as prolonged CLT and higher D-Dmax, along with lower D-Drate and Ks. Multiple regression analysis adjusted for fibrinogen and age, showed that PAI-1 antigen and TAFI activity independently predicted CLT in FVL(+/−) women on OC.Conclusion
FVL(+/−) is associated with hypofibrinolysis in apparently healthy women and third-generation OC administration unfavorably alters plasma clot characteristics in female FVL(+/−) carriers with a family history of thrombotic events. 相似文献11.
Introduction
Elevated soluble urokinase-type plasminogen activator receptor (suPAR) indicates an inflammatory state caused by conditions such as HIV and cancer. Recently suPAR was identified as an indicator of cardiovascular disease (CVD). CVD is highly prevalent in black South Africans, but the potential role of suPAR is unknown. We investigated suPAR as a possible marker of arterial stiffness in Africans and Caucasians.Methods
This study involved 207 Africans and 314 Caucasians (aged 20-70 yrs). C-reactive protein (CRP) and suPAR were determined in fasting blood samples. We measured blood pressure, pulse wave velocity (PWV) and Windkessel arterial compliance (Cwk).Results
Africans displayed higher suPAR, CRP, PWV and lower Cwk (p < 0.001) compared to Caucasians. SuPAR was elevated in Africans irrespective of gender and smoking. We found strong relationships between PWV and suPAR (r = 0.27; p < 0.001) and Cwk and suPAR (r = − 0.39; p < 0.001) in the whole group, but found no independent relationship of any arterial stiffness measure and suPAR in Africans after adjustment for confounders. Caucasian men indicated a weak significant independent association between Cwk and suPAR (β = − 0.09; p = 0.028).Conclusion
Africans had higher levels of suPAR and arterial stiffness than Caucasians (p < 0.001), but there was no independent relationship between arterial stiffness and suPAR in the Africans. It is speculated that due to the inflammatory role of suPAR, it will have stronger relationships with atherosclerosis, which has not yet manifested in this relatively young population group. SuPAR may therefore not be an ideal early marker of cardiovascular dysfunction, but may rather indicate established CVD. 相似文献12.
Introduction
There is a need for more reliable methods measuring the binding of coagulation factor VIII (FVIII) to von Willebrand factor (VWF) in plasma samples, for use in the clinical routine. We have developed such a method measuring FVIII binding in plasma, utilizing an ELISA system.Materials and Methods
Microtiter plates were coated with a monoclonal antibody (ESH-8), reacting with the C2 domain in FVIII. Thereafter the wells were treated with recombinant FVIII (Kogenate Bayer®). After washing, diluted plasma samples were added and incubated for 1 h. Then HRP-conjugated antibodies against VWF were added and used for quantification of bound VWF.Results
A strong signal to VWF concentration response was obtained. Plasma from patients with different types of von Willebrand disease gave frequently diminished responses. However, after correction for the VWF antigen levels, by calculation of FVIII binding/VWF antigen ratio, only the patients with known von Willebrand disease type 2 N (n = 4) had clearly abnormal results. The FVIII binding in 40 healthy individuals was determined as 1.08 ± 0.48 U/mL (SD). After correction for the VWF antigen levels the result was 0.94 ± 0.15. Thus, the SD declined substantially by this correction. The within-series CV and between-series CV were determined as 6.8 and 11.3%, respectively.Conclusions
We have established a simple and reliable method to detect decreased binding of FVIII to von Willebrand factor in plasma samples. The method can conveniently be used to study large populations, as well as finding minor binding defects in patients. 相似文献13.
Introduction
Plasminogen Activator Inhibitor-1 (PAI-1) is a member of the Serine Protease Inhibitor (SERPIN) gene family and a key regulator of fibrinolysis. PAI-1 is unique among SERPINs in its spontaneous transition to a latent, inactive state, with a half-life of approximately 2 hours under physiologic conditions. The biologic importance of the PAI-1 transition to latency is unknown. This study aimed to engineer transgenic overexpression of a stable murine PAI-1 variant to examine the physiologic effects in vivo from delayed transition of PAI-1 to latency.Materials and Methods
Ten independent transgenic lines were generated with expression of a stable PAI-1 variant driven by the hybrid CMV/chicken β-actin promoter.Results
Plasma PAI-1 levels in the transgenic founders ranged from 3.1 ± 0.1 ng/mL to 1268.8 ± 717.0 ng/mL. Quantitative PCR analysis in 3 transgenic lines demonstrated elevated PAI-1 mRNA in multiple tissues, with the highest increases observed in liver, brain, heart, and kidney. The fold-increase in PAI-1 mRNA over wild-type ranged from 2-fold to > 2000-fold. Immunohistochemistry showed increased PAI-1 in liver, kidney, heart, spleen, and lung. Histologic examination of transgenic mice showed no evidence of thrombosis. The two founders with the highest plasma PAI-1 levels failed to produce any transgenic offspring that survived to weaning, although genotyping of expired pups revealed successful transmission of the transgene.Conclusion
These results suggest that high expression of a stable variant of PAI-1 may be lethal in mice, while more moderate expression is generally well tolerated and produces no apparent thrombosis. 相似文献14.
Introduction
The haemostatic and biochemical abnormalities participate in the progression of cardiovascular disease (CVD) in peritoneally dialysed (PD) patients. Recently, the role of kynurenine (KYN) pathway of tryptophan (TRP) degradation in the development of CVD has been postulated.Materials and methods
The present study was undertaken to investigate haemostatic parameters, biochemical profiles and kynurenines in PD patients both with and without CVD compared to age- and sex-matched healthy controls.Results
The multiple biochemical abnormalities were present in PD patients, particularly in those with CVD. Tissue factor (TF), its inhibitor (TFPI), prothrombin fragment 1 + 2 (F1 + 2), urokinase-type plasminogen activator (uPA), its soluble receptor (suPAR), plasmin/antiplasmin (PAP) complexes, KYN, kynurenic (KYNA) and quinolinic (QA) acids levels were significantly higher, whereas TRP was significantly lower in the PD patients than in the controls. Tissue-type plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) were higher in the patients with CVD than in the patients without CVD and controls. PD patients with CVD had higher F1 + 2, and they had lower suPAR and KYNA levels compared with PD patients without CVD. KYNA was positively associated with TFPI, whereas its was inversely associated with F1 + 2 both in the whole PD group and in CVD patients. Logistic regression analysis showed that low KYNA, high glucose, low HDL-cholesterol levels and the duration of dialysis treatment were independently associated with the presence of CVD in PD patients.Conclusions
The present study suggests a relationship between kynurenine pathway of tryptophan degradation, haemostatic and biochemical disturbances and CVD prevalence in peritoneally dialyzed patients. 相似文献15.
Simpson ML Goldenberg NA Jacobson LJ Bombardier CG Hathaway WE Manco-Johnson MJ 《Thrombosis research》2011,127(4):317-323
Introduction
Thrombin and plasmin are the key enzymes involved in coagulation and fibrinolysis, respectively. Plasma coagulative and fibrinolytic potentials in normal children and adults, and in representative pathologically altered hemostatic states, were evaluated via simultaneous assessment of thrombin and plasmin generation.Materials and Methods
An assay of Simultaneous Thrombin and Plasmin generation (STP) was developed to measure thrombin and plasmin in plasma using individual fluorometric substrates. Coagulation is initiated with dilute tissue factor, phospholipid, and calcium in platelet-poor plasma; fibrinolysis is accelerated via tissue plasminogen activator (tPA). Abnormal states of hemostasis were investigated.Results
STP assay reproducibility and normal adult and pediatric values for measured and calculated parameters have been established. Onset of both thrombin and plasmin generation was significantly delayed in children relative to adults (p < 0.001) and the maximum amplitudes of thrombin and plasmin generation were less in children than adults (p < 0.01). No significant differences were measured among pediatric age groups. The most profound impairments in thrombin generation were observed for extrinsic and common pathway factor deficiencies, with the exception of afibrinogenemia. Plasmin generation was severely impaired in deficiencies of fibrinogen and plasminogen as well as with decreased tPA reagent concentration and addition of aminocaproic acid. Plasmin generation was greatly enhanced by alpha-2-antiplasmin deficiency and excess tPA reagent.Conclusion
Simultaneous assessment of thrombin and plasmin generation in plasma shows promise for affording an enhanced understanding of overall coagulative and fibrinolytic functions in physiological and pathologically altered states of hemostasis in children and adults. 相似文献16.
Introduction
Although fibrinolytic treatment has been used for decades, the interactions between the biochemical mechanisms and the mechanical forces of the streaming blood remain incompletely understood. Analysis of the blood clot surface in vitro was employed to study the concomitant effect of blood plasma flow and recombinant tissue plasminogen activator (rt-PA) on the degradation of retracted, non-occlusive blood clots. Our hypothesis was that a faster tangential plasma flow removed larger fragments and resulted in faster overall thrombolysis.Materials and Methods
Retracted model blood clots were prepared in an optical microscopy chamber and connected to an artificial perfusion system with either no-flow, or plasma flow with a velocity of 3 cm/s or 30 cm/s with or without added rt-PA at 2 µg/ml. The clot surface was dynamically imaged by an optical microscope for 30 min with 15 s intervals.Results
The clot fragments removed during rt-PA mediated thrombolysis ranged in size from that of a single red blood cell to large agglomerates composed of more than a thousand red blood cells bound together by partly degraded fibrin. The average and the largest discrete clot area change between images in adjacent time frames were significantly higher with the faster flow than with the slow flow (14,000 μm2 and 160,000 μm2 vs. 2200 μm2 and 10,600 μm2).Conclusions
On the micrometer scale, thrombolysis consists of sequential removal of clot fragments from the clot surface. With increasing tangential plasma flow velocity, the size of the clot fragments and the overall rate of thrombolysis increases. 相似文献17.
Raeven P Feichtinger GA Weixelbaumer KM Atzenhofer S Redl H Van Griensven M Bahrami S Osuchowski MF 《Thrombosis research》2012,129(5):e238-e245
Introduction
Plasminogen activator inhibitor type 1 (PAI-1) co-induces septic coagulopathy. We aimed to characterize spatiotemporal PAI-1 gene/protein changes occurring in acute sepsis and tested whether PAI-1 fluctuations correlate with sepsis severity and early outcome.Materials and Methods
Female mice underwent cecal ligation and puncture (CLP) in three experiments. I: mild (23G needle) CLP to compare circulating PAI-1 to its organ gene expression within 0-24 h. II: mild or severe (17G) CLP to asses differences in PAI-1 organ-specific expression and in coagulation/fibrinolysis. III: moderate (18G) CLP to characterize circulating PAI-1 in survivors (SUR), and to retrospectively compare it to dying (DIE) mice.Results
In mild sepsis, the trajectory of circulating PAI-1 (1089 ng/ml peak at 24 h) was identical to PAI-1 gene expression in the left cranial vena cava (LCVC; 39-fold peak at 24 h). PAI-1 expression rise was immediate (60-fold at 6 h) and sustained in the liver, but marginal in the kidney, lungs and heart. Body temperature decrease correlated with the PAI-1 expression increase in the liver (rho = − 0.79), and blood (protein, rho = − 0.53). Regardless of severity, PAI-1 gene expression remained unaltered except the LCVC where it was > 3-fold higher in 17G (vs. 23G). Severe sepsis extended activated partial thromboplastin/pro-thrombin time and increased circulating PAI-1, while antithrombin and fibrinogen decreased at 6 and/or 24 h (vs. 23G). Within 24 h of death, circulating PAI-1 in DIE was > 3-fold higher versus SUR.Conclusions
Polymicrobial sepsis caused a gradual circulating PAI-1 release and highly variable gene expression response pattern in organs. Only circulating PAI-1 and PAI-1 expression in the LCVC correlated with response severity and/or outcome. 相似文献18.
Background
Orthopedic hip and knee surgeries are followed by a hypercoagulable state. Heparanase is implicated in inflammation, coagulation activation and angiogenesis. Recently, heparanase was shown to directly interact with tissue factor (TF) and to enhance the generation of factor Xa (Nadir et al., Haematologica, 2010). In addition, an assay assessing heparanase procoagulant activity has been lately developed (Nadir et al., Thromb Res, 2011). In the present study heparanase level and procoagulant activity in patients undergoing orthopedic surgery were assessed.Methods
The study group included 50 orthopedic patients. 31 patients underwent hip surgery and 19 had knee operation. 15 individuals suffered from traumatic hip fractures and 35 had osteoarthrosis of hip or knee joints. All patients received prophylactic dose of enoxaparin starting 6-8 hours post operation and lasting for 5 weeks. Plasma samples were drawn preoperatively and at 1 hour, 1 week and 1 month post operation. Samples were tested for heparanase levels by ELISA and TF/heparanase complex activity, TF activity, heparanase procoagulant activity, factor Xa and thrombin levels using chromogenic substrates.Results
Heparanase levels were significantly higher 1 hour and 1 week post operatively compared to preoperative levels (p < 0.05, p < 0.005, respectively). The most dramatic changes were observed in heparanase procoagulant activity reaching a 2 fold increase 1 week postoperatively and 1.7 fold increase 1 month after surgery (p < 0.0001, p < 0.0001, respectively). Levels of factor Xa and thrombin did not significantly change.Conclusions
Heparanase is involved in coagulation activation of orthopedic surgery patients. Heparanase procoagulant activity is highest 1 week postoperatively and remains high 1 month after operation. Considering extending prophylactic anticoagulant therapy or evaluating heparanase procoagulant activity may potentially prevent late thrombotic events. 相似文献19.
Introduction
The aim of this study was to evaluate the plasma levels of endothelial haemostatic markers - von Willebrand factor (vWF), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (t-PA) and soluble thrombomodulin (sTM) — in asymptomatic, nonsmoking members of families with familial combined hyperlipidemia (FCH). We investigated the association between these factors and the intima-media thickness (IMT) of the common carotid artery, selected risk factors of atherosclerosis and markers of insulin resistance.Methods
82 members of 29 FCH families were divided into two groups: HL (probands and hyperlipidemic first-degree relatives, n = 47) and NL (normolipidemic first-degree relatives, n = 35). The control groups C-HL (n = 20) and C-NL (n = 20) consisted of sex- and age-matched healthy individuals. IMT was measured by ultrasound at a far wall of both common carotid arteries.Results
Compared with healthy controls, hyperlipidemic subjects had significantly higher levels of vWF (146.4 ± 73.2% versus 112.2 ± 29.4%, p < 0.05), of PAI-1 (102.4[83.0-117.0] ng/ml versus 63.5[31.8-87.3] ng/ml, p < 0.01) and of t-PA (5.1[2.5-7.9] ng/ml versus 3.4[1.4-5.8] ng/ml, p < 0.05). They had increased IMT, which correlated with vWF (r = 0.29, p < 0.05). Their normolipidemic relatives had significantly higher levels of vWF (137.2 ± 42.8% versus 106.6 ± 24.0%, p < 0.01) and of PAI-1 (75.3[53.2-92.0] ng/ml versus 48.6[37.4-85.9] ng/ml, p < 0.05). Levels of vWF, PAI-l and t-PA were independently associated with several markers of insulin resistance.Conclusions
Asymptomatic members of FCH families have increased endothelial haemostatic factors— vWF, PAI-1, t-PA, which are associated with insulin resistance. VWF correlates with morphological vascular changes, detected by the increase of IMT, presented in only hyperlipidemic subjects. 相似文献20.
LL Gong JH Peng FF Han J Zhu LH Fang YH Wang GH Du HY Wang LH Liu 《Thrombosis research》2012,130(3):e43-e51