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1

Topical thrombin preparations and their use in cardiac surgery  

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Full Text Available Brianne L Dunn1, Walter E Uber1, John S Ikonomidis21Department of Pharmacy Services and 2Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, South Carolina, USAAbstract: Coagulopathic bleeding may lead to increased morbidity and mortality after cardiac surgery. Topical bovine thrombin has been used to promote hemostasis after surgical procedures for over 60 years and is used frequently as a topical hemostatic agent in cardiac surgery. Recently, use of bovine thrombin has been reported to be associated with increased risk for anaphylaxis, thrombosis, and immune-mediated coagulopathy thought secondary to the production of antifactor V and antithrombin antibodies. In patients who develop bovine thrombin-induced immune-mediated coagulopathy, clinical manifestations may range from asymptomatic alterations in coagulation tests to severe hemorrhage and death. Patients undergoing cardiac surgical procedures may be at increased risk for development of antibodies to bovine thrombin products and associated complications. This adverse immunologic profile has led to the development of alternative preparations including a human and a recombinant thrombin which have been shown to be equally efficacious to bovine thrombin and have reduced antigenicity. However, the potential benefit associated with reduced antigenicity is not truly known secondary to the lack of long-term experience with these products. Given the potentially higher margin of safety and less stringent storage concerns compared to human thrombin, recombinant thrombin may be the most reasonable approach in cardiac surgery.Keywords: bovine thrombin, human thrombin, recombinant thrombin, immune-mediated coagulopathy, topical hemostatic agents, thrombin 

Brianne L Dunn

2009-10-01

2

Topical recombinant thrombin at a concentration of 1000 IU/mL reliably shortens in vivo TTH and delivers durable hemostasis in the presence of heparin anticoagulation and clopidogrel platelet inhibition in a rabbit model of vascular bleeding  

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Full Text Available Abstract Background This study was designed to evaluate the effect of recombinant human thrombin (rThrombin concentration on time to hemostasis (TTH, clot durability, and clot strength in settings that replicate the heparinization and platelet inhibition often found in surgical populations. Methods A modified, anticoagulated rabbit arteriovenous shunt preparation was selected to model vascular anastomotic bleeding. Rabbits were treated with heparin or heparin + clopidogrel and TTH was measured after applying a range of topical rThrombin concentrations or placebo, in combination with absorbable gelatin sponge, USP. Treatments (placebo, rThrombin were randomly assigned and the investigator was blinded to treatment. TTH was evaluated with the Kaplan-Meier method. After hemostasis was achieved, clot burst assessment was performed for heparin + clopidogrel treated animals. Clot viscoelastic strength and kinetics were measured in ex-vivo samples using thromboelastography (TEG methods. Results TTH decreased with increasing concentrations of rThrombin in heparin-treated animals and was shorter after treatment with 1000 IU/mL rThrombin (73 seconds than with 125 IU/mL rThrombin (78 seconds; p = 0.007. TTH also decreased with increasing concentrations of rThrombin in heparin + clopidogrel treated animals; again it was significantly shorter after treatment with 1000 IU/mL rThrombin (71 seconds than with 125 IU/mL rThrombin (177 seconds; p  Conclusion In an animal model designed to replicate the anti-coagulation regimens encountered in clinical settings, topical rThrombin at 1000 IU/mL more reliably controlled the pharmacological effects of heparin or heparin + clopidogrel on hemostasis than rThrombin at 125 IU/mL. Results from in vitro assessments confirmed a positive relationship between the amount of rThrombin activity and both the rate of clot formation and clot strength.

Garcia Richard

2009-11-01

3

Recombinant hirudin: kinetic mechanism for the inhibition of human thrombin.  

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Recombinant hirudin variant-2(Lys47), was found to be a competitive inhibitor of human alpha-thrombin with respect to peptidyl p-nitroanilide substrates. These results contrast with those of Degryse and coworkers that suggest that recombinant hirudin variant-2(Lys47) inhibited thrombin by a noncompetitive mechanism [Degryse et al. (1989) Protein Engng, 2, 459-465]. gamma-Thrombin, which can arise from alpha-thrombin by autolysis, was shown to have an affinity for recombinant hirudin variant-2(Lys47) that was four orders of magnitude lower than that of alpha-thrombin. It was demonstrated that the apparent noncompetitive mechanism observed previously was probably caused by a contamination of the thrombin preparation by gamma-thrombin. Comparison of the inhibition of alpha-thrombin by recombinant hirudins variant-2(Lys47) and variant-1, which differ from one another in eight out of 65 amino acids, indicated that the two variants have essentially the same kinetic parameters. PMID:1857714

Stone, S R; Hofsteenge, J

1991-02-01

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A method for the prevention of thrombin-induced degradation of recombinant proteins  

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A new strategy to prevent degradation of recombinant proteins caused by non-specific cleavage by thrombin is described. We demonstrate that degradation due to non-specific cleavage of recombinant protein mediated by thrombin can be completely prevented by separation of thrombin from the recombinant protein on spin columns packed with heparin-sepharose. This method is generally applicable to all recombinant proteins that require the thrombin for the cleavage of affinity tags for purification. ...

Rajalingam, Dakshinamurthy; Kathir, Karuppanan Muthusamy; Ananthamurthy, Koteshwara; Adams, Paul D.; Kumar, Thallapuranam Krishnaswamy Suresh

2008-01-01

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Risk of bleeding in surgical patients treated with topical bovine thrombin sealants: a review of the literature  

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Full Text Available Abstract Background One of the most anticipated, but potentially serious complications during or after surgery are bleeding events. Among the many potential factors associated with bleeding complications in surgery, the use of bovine thrombin has been anecdotally identified as a possible cause of increased bleeding risk. Most of these reports of bleeding events in association with the use of topical bovine thrombin have been limited to case reports lacking clear cause and effect relationship determination. Recent studies have failed to establish significant differences in the rates of bleeding events between those treated with bovine thrombin and those treated with either human or recombinant thrombin. Methods We conducted a search of MEDLINE for the most recent past 10 years (1997–2007 and identified all published studies that reported a study of surgical patients with a clear objective to examine the risk of bleeding events in surgical patients. We also specifically noted the reporting of any topical bovine thrombin used during surgical procedures. We aimed to examine whether there were any differences in the risk of bleeds in general surgical populations as compared to those studies that reported exposure to topical bovine thrombin. Results We identified 21 clinical studies that addressed the risk of bleeding in surgery. Of these, 5 studies analyzed the use of bovine thrombin sealants in surgical patients. There were no standardized definitions for bleeding events employed across these studies. The rates of bleeds in the general surgery studies ranged from 0.1%–20.2%, with most studies reporting rates between 2.6%–4%. The rates of bleeding events ranged from 0.0%–13% in the bovine thrombin studies with most studies reporting between a 2%–3% rate. Conclusion The risk of bleeds was not clearly different in those studies reporting use of bovine thrombin in all patients compared to the other surgical populations studied. A well-designed and well-controlled study is needed to accurately examine the bleeding risks in surgical patients treated and unexposed to topical bovine thrombin, and to evaluate the independent risk associated with topical bovine thrombin as well as other risk factors.

Crean Sheila

2008-03-01

6

Postoperative coagulopathy in a pediatric patient after exposure to bovine topical thrombin.  

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Severe postoperative coagulopathy developed in a child with congenital heart disease due to a factor V inhibitor from repetitive exposure to bovine topical thrombin. This case report alerts pediatric providers to consider these inhibitors when postoperative coagulopathy occurs. Potential treatment options are reviewed. PMID:17383385

Crow, Sheri S; Sullivan, Vita V; Aysola, Agnes E; Key, Nigel S; Harker-Murray, Paul; Foker, John E; Steiner, Marie E

2007-04-01

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Assessment of thrombus imaging potency of thrombin-targeting recombinant hirudin in vitro and in vivo  

International Nuclear Information System (INIS)

The purpose of this study is to evaluate the effect of recombinant hirudin HV2 (rHHV2) as a thrombus imaging agent. "1"2"5I-rHHV2 and "1"2"5I-Th were prepared with Chloramine method, the labeling rate were 86.64% and 62.20%, with the radioactive purity of 89.70% and 91.22%, with the specific activity of 22.4 TBq/mmol and 94.43 TBq/mmol respectively. The competitive radioassay showed that the Th-fibrin complex formation did not affect the ability of rHHV2 binding with Th. In the complex, the molecular binding ratio of rHHV2 to Th and fibrinogen was 14:14:1. "9"9"mTc-rHHV2 was prepared by 2-iminothiolane modified method, the labeled rate was 94%, with the radioactive purity of 93.90%, with the specific activity of 2.30 TBq/mmol. It was used to image fresh thrombi on arteries and veins of dog or rabbit (30 ?g/kg). In SPECT images, all thrombin were clearly visible, arterial thrombosis imaging can be seen clearly within 45 min after injection and fade away slowly, venous thrombosis imaging also can be seen within 30 min after injection and quantitative imaging ratios between the thrombus and opposite vessel increased following the time. Biodistribution studies in mouse demonstrated that rHHV2 was excreted from kidneys. These data indicate that Th in Th-fibrin complex could be a potent target for diagnosis of thrombus and "9"9"mTc-rHHV2 could be a new thrombotic imaging agent. (authors)

2003-01-01

8

Recombinant human activated protein C resets thrombin generation in patients with severe sepsis - a case control study  

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Introduction Recombinant human activated protein C (rhAPC) is the first drug for which a reduction of mortality in severe sepsis has been demonstrated. However, the mechanism by which this reduction in mortality is achieved is still not clearly defined. The aim of the present study was to evaluate the dynamics of the anticoagulant, anti-inflammatory and pro-fibrinolytic action of rhAPC in patients with severe sepsis, by comparing rhAPC-treated patients with case controls. Methods In this prospectively designed multicenter case control study, 12 patients who were participating in the ENHANCE study, an open-label study of rhAPC in severe sepsis, were treated intravenously with rhAPC at a constant rate of 24 ?g/kg/h for a total of 96 h. Twelve controls with severe sepsis matching the inclusion criteria received standard therapy. The treatment was started within 48 h after the onset of organ failure. Blood samples were taken before the start of the infusion and at 4, 8, 24, 48, 96 and 168 h, for determination of parameters of coagulation and inflammation. Results Sepsis-induced thrombin generation as measured by thrombin-antithrombin complexes and prothrombin fragment F1+2, was reset by rhAPC within the first 8 h of infusion. The administration of rhAPC did not influence parameters of fibrinolysis and inflammation. There was no difference in outcome or occurrence of serious adverse events between the treatment group and the control group. Conclusion Sepsis-induced thrombin generation in severely septic patients is reset by rhAPC within the first 8 h of infusion without influencing parameters of fibrinolysis and inflammation.

de Pont, Anne-Cornelie JM; Bakhtiari, Kamran; Hutten, Barbara A; de Jonge, Evert; Vroom, Margreeth B; Meijers, Joost CM; Buller, Harry R; Levi, Marcel

2005-01-01

9

Thrombin Time  

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... this website will be limited. Search Help? Thrombin Time Share this page: Was this page helpful? Also ... for monitoring dabigatran therapy? 1. Can the thrombin time be performed in my doctor's office? With the ...

10

Interaction of thrombin with PAR1 and PAR4 at the thrombin cleavage site†  

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Investigations determined the critical amino acids for ?-thrombin’s interaction with protease activated receptors 1 and 4 (PAR1 and PAR4) at the thrombin cleavage site. Recombinant PAR1-wild type (wt) exodomain was cleaved by ?-thrombin with a Km of 28 ?M, a kcat of 340 s-1 and kcat/Km of 1.2×107. When the P4 or P2 position was mutated to alanine, PAR1-L38A or PAR1-P40A, respectively, the Km was unchanged, 29 or 23 ?M, respectively; however the kcat and kcat/Km were reduced in each cas...

Nieman, Marvin T.; Schmaier, Alvin H.

2007-01-01

11

Prevention of postoperative intracerebral hemorrhage with topical recombinant factor XIII in the rat.  

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Factor XIII is an endogenous clotting factor that retards thrombus degradation by cross-linking fibrin. To determine the efficacy of Factor XIII as a topical clot-stabilizing agent in preventing postoperative hemorrhage associated with coagulopathy, a rat model of experimental craniotomy and standardized bilateral frontal corticectomy was developed. In 25 rats (50 lesions), recombinant human Factor XIII or placebo solution was topically applied to corticectomy cavities after hemostasis was achieved; each animal served as its own control. In 20 rats, heparin sulfate (100 U/kg.h) was initiated intraperitoneally 3 days after surgery and was continually administered by an Alzet pump for 7 days, compared with a control group of 5 rats receiving saline intraperitoneally. The volume of intracranial hemorrhage was quantitatively determined from coronal sections by use of automated image analysis. Large (> 50 mm3) intracerebral hemorrhages were significantly more frequent in placebo (60%)- compared with recombinant Factor XIII (15%)-treated lesions (P < 0.01) in animals receiving heparin. The topical application of clot-stabilizing agents such as Factor XIII may reduce the risk of postoperative intracranial hemorrhage, especially in high-risk patients with coagulopathy. PMID:8474654

Laohaprasit, V; Edwards, M W; Mayberg, M R

1993-04-01

12

BLA 125248 Thrombin (Recombinant) Recothrom  

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... (~et Z(~II~Y~~·Cil:I.~::; M~\\lI~ PTA 11l1pld~i GLP IV. SC (~et ZGI i~~~~·h:;:1 :\\'cti: Oa' '.~~e of th~ ttllll ';rcp:c;!f' i:n.::udi~ dli 3pplic3tk.u ci rb. ...

13

The use of thrombin in the radiology department.  

LENUS (Irish Health Repository)

Thrombin is a naturally occurring coagulation protein that converts soluble fibrinogen into insoluble fibrin and plays a vital role in the coagulation cascade and in turn haemostasis. Thrombin also promotes platelet activation. In the last few years, there has been a rapid increase in the use of thrombin by radiologists in a variety of clinical circumstances. It is best known for its use in the treatment of pseudoaneurysms following angiography. However, there are now a variety of cases in the literature describing the treatment of traumatic, inflammatory and infected aneurysms with thrombin in a variety of locations within the human body. There have even been recent reports describing the use of thrombin in conventional aneurysms as well as ruptured aneurysms. Its use has also been described in the treatment of endoleaks (type II) following aneurysm repair. In nearly all of these cases, treatment with thrombin requires imaging guidance. Recently, thrombin has also been used as a topical treatment post-percutaneous intervention to reduce or stop bleeding. Most radiologists have only a limited knowledge of the pharmacodynamics of thrombin, its wide range of utilisation and its limitations. Apart from a few case reports and case series, there is little in the radiological literature encompassing the wide range of applications that thrombin may have in the radiology department. In this review article, we comprehensively describe the role and pathophysiology of thrombin, describing with examples many of its potential uses. Techniques of usage as well as pitfalls and limitations are also described.

Ward, E

2009-03-01

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The use of thrombin in the radiology department  

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Thrombin is a naturally occurring coagulation protein that converts soluble fibrinogen into insoluble fibrin and plays a vital role in the coagulation cascade and in turn haemostasis. Thrombin also promotes platelet activation. In the last few years, there has been a rapid increase in the use of thrombin by radiologists in a variety of clinical circumstances. It is best known for its use in the treatment of pseudoaneurysms following angiography. However, there are now a variety of cases in the literature describing the treatment of traumatic, inflammatory and infected aneurysms with thrombin in a variety of locations within the human body. There have even been recent reports describing the use of thrombin in conventional aneurysms as well as ruptured aneurysms. Its use has also been described in the treatment of endoleaks (type II) following aneurysm repair. In nearly all of these cases, treatment with thrombin requires imaging guidance. Recently, thrombin has also been used as a topical treatment post-percutaneous intervention to reduce or stop bleeding. Most radiologists have only a limited knowledge of the pharmacodynamics of thrombin, its wide range of utilisation and its limitations. Apart from a few case reports and case series, there is little in the radiological literature encompassing the wide range of applications that thrombin may have in the radiology department. In this review article, we comprehensively describe the role and pathophysiology of thrombin, describing with examples many of its potential uses. Techniques of usage as well as pitfalls and limitations are also described. (orig.)

Ward, E.; Buckley, O.; Browne, R.F. [Adelaide and Meath Hospitals incorporating the National Children' s Hospital (AMNCH), Department of Radiology, Dublin 24 (Ireland); Collins, A. [Royal Victoria Hospital, Department of Radiology, Belfast (United Kingdom); Torreggiani, W.C. [Adelaide and Meath Hospitals incorporating the National Children' s Hospital (AMNCH), Department of Radiology, Dublin 24 (Ireland)]|[Adelaide and Meath Hospital, Department of Radiology, Dublin 24 (Ireland)

2009-03-15

15

New direct thrombin inhibitors.  

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Direct thrombin inhibitors (DTIs) are a class of anticoagulants that bind selectively to thrombin and block its interaction with its substrates. Dabigatran etexilate and AZD0837, the new generation of DTIs, are now under intense development, and are potentially of great interest for internists. Dabigatran etexilate is a potent, non-peptidic small molecule that specifically and reversibly inhibits both free and clot-bound thrombin by binding to the active site of thrombin molecule. It has been already licensed in the European Union and in Canada for the prevention of VTE in patients undergoing hip- and knee-replacement surgery. Ongoing trials are evaluating its efficacy and safety for the treatment of deep venous thrombosis and pulmonary embolism, primary and secondary prevention of VTE, prevention of systemic embolism in patients with non-valvular atrial fibrillation, and prevention of cardiac events in patients with acute coronary syndromes. AZD0837 is the prodrug of ARH06737, a potent, competitive, reversible inhibitor of free and fibrin-bound thrombin. At present, only limited, preclinical, phase I and phase II clinical data have been presented. The drug has now entered a phase III clinical program in the population of patients with atrial fibrillation. Their properties and the oral administration render these compounds, theoretically, more convenient than both vitamin K antagonist and low molecular weight heparins. However, only reports from clinical practice patterns over the next months and years will tell us how and when to use the new DTIs. PMID:19756950

Squizzato, Alessandro; Dentali, Francesco; Steidl, Luigi; Ageno, Walter

2009-12-01

16

Autoactivation of Thrombin Precursors*  

Science.gov (United States)

Trypsin-like proteases are synthesized as inactive zymogens and convert to the mature form upon activation by specific enzymes, often assisted by cofactors. Central to this paradigm is that the zymogen does not convert spontaneously to the mature enzyme, which in turn does not feed back to activate its zymogen form. In the blood, the zymogens prothrombin and prethrombin-2 require the prothrombinase complex to be converted to the mature protease thrombin, which is unable to activate prothrombin or prethrombin-2. Here, we show that replacement of key residues within the activation domain causes these zymogens to spontaneously convert to thrombin. The conversion is started by the zymogen itself, which is capable of binding ligands at the active site, and is abrogated by inactivation of the catalytic residue Ser-195. The product of autoactivation is functionally and structurally equivalent to wild-type thrombin. Zymogen autoactivation is explained by conformational selection, a basic property of the trypsin fold uncovered by structural and rapid kinetics studies. Both the zymogen and protease undergo a pre-existing equilibrium between active and inactive forms. The equilibrium regulates catalytic activity in the protease and has the potential to unleash activity in the zymogen to produce autoactivation. A new strategy emerges for the facile production of enzymes through zymogen autoactivation that is broadly applicable to trypsin-like proteases of biotechnological and clinical interest.

Pozzi, Nicola; Chen, Zhiwei; Zapata, Fatima; Niu, Weiling; Barranco-Medina, Sergio; Pelc, Leslie A.; Di Cera, Enrico

2013-01-01

17

Recombinant snake venom prothrombin activators  

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Three prothrombin activators; ecarin, which was originally isolated from the venom of the saw-scaled viper Echis carinatus, trocarin from the rough-scaled snake Tropidechis carinatus, and oscutarin from the Taipan snake Oxyuranus scutellatus, were expressed in mammalian cells with the purpose to obtain recombinant prothrombin activators that could be used to convert prothrombin to thrombin. We have previously reported that recombinant ecarin can efficiently generate thrombin without the need ...

2013-01-01

18

Crystal structure of the thrombin-hirudin complex: a novel mode of serine protease inhibition.  

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Thrombin is a serine protease that plays a central role in blood coagulation. It is inhibited by hirudin, a polypeptide of 65 amino acids, through the formation of a tight, noncovalent complex. Tetragonal crystals of the complex formed between human alpha-thrombin and recombinant hirudin (variant 1) have been grown and the crystal structure of this complex has been determined to a resolution of 2.95 A. This structure shows that hirudin inhibits thrombin by a previously unobserved mechanism. In contrast to other inhibitors of serine proteases, the specificity of hirudin is not due to interaction with the primary specificity pocket of thrombin, but rather through binding at sites both close to and distant from the active site. The carboxyl tail of hirudin (residues 48-65) wraps around thrombin along the putative fibrinogen secondary binding site. This long groove extends from the active site cleft and is flanked by the thrombin loops 35-39 and 70-80. Hirudin makes a number of ionic and hydrophobic interactions with thrombin in this area. Furthermore hirudin binds with its N-terminal three residues Val, Val, Tyr to the thrombin active site cleft. Val1 occupies the position P2 and Tyr3 approximately the position P3 of the synthetic inhibitor D-Phe-Pro-ArgCH2Cl. Thus the hirudin polypeptide chain runs in a direction opposite to that expected for fibrinogen and that observed for the substrate-like inhibitor D-Phe-Pro-ArgCH2Cl. PMID:2369893

Grütter, M G; Priestle, J P; Rahuel, J; Grossenbacher, H; Bode, W; Hofsteenge, J; Stone, S R

1990-08-01

19

[Preparation of thrombin affinity chromatography media].  

Science.gov (United States)

The preparation of thrombin affinity chromatography media is described in this paper. First, the thrombin affinity chromatography media was prepared through thrombin coupled with cyanogen bromide activated agarose. And then the enzyme activity of thrombin on the coupled media was measured by chromogenic substrate method. The conditions were confirmed based on the enzyme activity of thrombin on the coupled media. The optimum conditions were as follows: the use of Na2CO3-NaHCO3 (containing 0.5 mol/L NaCl) solution of pH 8.3 as the reaction solution, 200 U thrombin per 1 g agarose, and reaction for 10 h at room temperature. The prepared affinity chromatography media had good stability, on which 70.6% of the enzyme activity of thrombin existed after 40 days' storage. The thrombin affinity chromatography media can be widely applied in the screening and purification of thrombin inhibitors in natural products. PMID:24369620

Wang, Xiongfei; Zhang, Yujie; Ye, Jing; Luo, Zhiqiang; Zhan, Xueyan; Yuan, Ruijuan

2013-08-01

20

Refined structure of the hirudin-thrombin complex.  

Science.gov (United States)

The structure of a recombinant hirudin (variant 2, Lys47) human alpha-thrombin complex has been refined using restrained least-squares methods to a crystallographic R-factor of 0.173. The hirudin structure consists of an N-terminal domain folded into a globular unit and a long 17-peptide C-terminal in an extended chain conformation. The N-terminal domain binds at the active-site of thrombin where Ile1' to Tyr3' penetrates to the catalytic triad. The alpha-amino group of Ile1' of hirudin makes a hydrogen bond with OG of Ser195 of thrombin, the side-chains of Ile1' and Tyr3' occupy the apolar site, Thr2' is at the entrance to, but does not enter, the S1 specificity site and Ile1' to Tyr3' form a parallel beta-strand with Ser214 to Gly219. The latter interaction is antiparallel in all other serine proteinase-protein inhibitor complexes. The extended C-terminal segment of hirudin, which is abundant in acidic residues, makes many electrostatic interactions with the fibrinogen binding exosite while the last five residues are in a 3(10) helical turn residing in a hydrophobic patch on the thrombin surface. The precision of the complementarity displayed by these two molecules produces numerous interactions, which although independently generally weak, together are responsible for the high degree of affinity and specificity. Although hirudin-thrombin and D-Phe-Pro-Arg-chloromethyl ketone-thrombin differ in conformation in the autolysis loop (Lys145 to Gly150), this is most likely due to different crystal packing interactions and changes in circular dichroism between the two are probably due to the inherent flexibility of the loop. An RGD sequence, which is generally known to be involved in cell surface receptor interactions, occurs in thrombin and is associated with a long solvent channel filled with water molecules leading to the surface from the end of the S1 site. However, the RGD triplet does not appear to be able to interact in concert in a surface binding mode. PMID:1920434

Rydel, T J; Tulinsky, A; Bode, W; Huber, R

1991-09-20

 
 
 
 
21

Recombinant snake venom prothrombin activators.  

Science.gov (United States)

Three prothrombin activators; ecarin, which was originally isolated from the venom of the saw-scaled viper Echis carinatus, trocarin from the rough-scaled snake Tropidechis carinatus, and oscutarin from the Taipan snake Oxyuranus scutellatus, were expressed in mammalian cells with the purpose to obtain recombinant prothrombin activators that could be used to convert prothrombin to thrombin. We have previously reported that recombinant ecarin can efficiently generate thrombin without the need for additional cofactors, but does not discriminate non-carboxylated prothrombin from biologically active ?-carboxylated prothrombin. Here we report that recombinant trocarin and oscutarin could not efficiently generate thrombin without additional protein co-factors. We confirm that both trocarin and oscutarin are similar to human coagulation Factor X (FX), explaining the need for additional cofactors. Sequencing of a genomic fragment containing 7 out of the 8 exons coding for oscutarin further confirmed the similarity to human FX. PMID:23111318

Lövgren, Ann

2013-01-01

22

Effect of Electronic Polarization to Human ?-Thrombin  

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The polarized protein-specific charges (PPC) of human ?-thrombin (thrombin) and its inhibitor (L86) are made possible by employing the recently developed molecular fractionation with conjugate caps approach incorporated the Poisson—Boltzmann model. Molecular dynamics (MD) simulations of thrombin have been carried out to investigate the dynamics and stability of the thrombin-inhibitor using PPC and AMBER charges respectively. Detailed analysis and comparison of MD results show that the PPC can correctly describe the polarized state of the thrombin and L86. Especially, the root-mean-square deviation of backbone atoms and the hydrogen bonds using PPC are more stable than the AMBER charge. The present results indicate that protein polarization plays critical roles in maintaining the compact structure of thrombin.

Duan, Li-Li; Li, Zong-Chao; He, Xiang; Zhang, Qing-Gang

2014-04-01

23

Zinc modulates thrombin adsorption to fibrin  

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Human thrombin with high affinity to Sepharose insolubilized fibrin monomers (high-affinity thrombin) was used to investigate the effect of Zn(II) on the thrombin adsorption to fibrin. Results showed that at Zn(II) concentrations exceeding 100 mumols/l, thrombin binding to fibrin was decreased concomitant with the Zn(II) concentration and time; at lower Zn(II) concentrations, thrombin adsorption was enhanced. Experimental results were identical by using 125I-labelled high-affinity alpha-thrombin or by measuring the thrombin activity either by chromogenic substrate or by a clotting time method. In contrast, Ca(II) alone (final conc. 3 mmol/l) or in combination with Zn(II) was not effective. However, at higher Ca(II) concentrations (7.5-15 mmol/l), thrombin adsorption was apparently decreased. Control experiments revealed that Zn(II) had no impact on the clottability of fibrinogen, and that the results of the experiments with Ca(II) were not altered by possible cross-linking of fibrin. We conclude that unlike Ca(II), Zn(II) is highly effective in modulating thrombin adsorption to fibrin.

Hopmeier, P.; Halbmayer, M.; Fischer, M.; Marx, G. (Krankenhaus Wien-Lainz, Vienna (Austria))

1990-05-01

24

Systemic thrombin generation by glucose  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Systemic thrombin activity (F2a, i.e. thrombin protected and transported by a2- macroglobulin, is a new biomarker for the activation state of coagulation in vivo. F2a > 120% of normal diagnoses a pathologic disseminated intravascular coagulation (PIC in humans, either acute or chronic. Since glucose triggers intrinsic coagulation, the present work aimed to quantify systemic thrombin generation induced by glucose in vivo in mice. Material and Methods: Balb/c mice were i.p. injected with different concentrations of glucose (0 - 0.3 mmoles. After 0 - 3 h EDTA-blood was withdrawn, centrifuged, and the plasma was stabilized 1 + 1 with 2.5 M arginine, pH 8.6, and analyzed for systemically circulating F2a (that is F2a.?2M. The F2a.?2M activity in mice without glucose injection was defined as 100% of murine norm. Results: 1 h after i.p. injection 0.1 - 0.3 mmoles glucose resulted in about 1.4 fold increase of plasmatic glucose and in about 2.5 fold increase of systemic F2a activity. At the 45 min time interval between i.p. injection of 0.038 mmoles glucose and blood withdrawing an approximately 1.5fold increase of plasma glucose caused a 4fold increase in systemic F2a. Discussion: When systemic F2a reaches 120% of the normal, the normal human intravascular coagulation (NIC turns to the pre-phase of pathologic plasmatic intravascular coagulation (PIC-0 also defined as pre-PIC. At 150% systemic F2a, the PIC-0 changes to PIC-1 which is the common pathologic plasmatic intravascular coagulation (typical PIC. At 200% systemic F2a, PIC-1 changes to PIC-2 (consumption PIC. The present assay technique seems to be suitable in judging the coagulation activation state of any mammalian blood. Diabetic patients should be monitored for the new biomarker systemic F2a similarly as for the old biomarker glycated hemoglobin (HbA1c. The target systemic F2a range should be NIC, preferably around 100% of normal.

Hani Harb

2012-02-01

25

Thrombin activity in normal vitreous liquid.  

Science.gov (United States)

An intact blood-retina barrier (BRB) ensures the homeostatic regulation of the retinal environment by preventing proteins and enzymes to pass from the blood stream into the retinal tissue as well as the vitreous cavity ('nonleaky eyes'). Nevertheless, thrombin is needed within the eye to avoid bleeding events. It might, furthermore, play an essential role in preventing BRB breakdown ('leaky eyes'). Until today, the intraocular thrombin activity as well as the source of the latter has not been investigated. The present work was conducted to evaluate whether intravitreal thrombin activity is present in eyes without BRB breakdown. Therefore, 16 vitreal taps were harvested at the beginning of a standard 23-gauge three-port pars plana vitrectomy. These 200??l undiluted vitreous samples were instantly stabilized by 1?+?1 mixture with 5% human albumin, followed by 1?+?1 mixture of such an aliquot with 2.5?mol/l arginine, pH 8.6, and frozen at -20°C. After thawing at 23°C, thrombin activity was analyzed chromogenically in the presence of arginine protection against unspecific cleavage of the chromogenic substrate. Intravitreal thrombin was detected in all 16 analyzed samples and thrombin activity exhibited to be 1.5?±?1.0?mIU/ml (mean value?±?SD; range: 0.2-3.25?mIU/ml). Thus, our investigation is the first successful quantification of the physiologic intraocular activity of thrombin. Further studies will evaluate intravitreal thrombin activities in eyes with BRB breakdown and compare those results with the physiologic activities demonstrated herein. Standardized intraocular thrombin activity might be a new diagnostic parameter in ophthalmology. PMID:24172337

Bertelmann, Thomas; Sekundo, Walter; Stief, Thomas; Mennel, Stefan

2014-01-01

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Thrombin-mediated activation of factor XI results in a thrombin-activatable fibrinolysis inhibitor-dependent inhibition of fibrinolysis.  

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Recently, it has been shown that Factor XI can be activated by thrombin, and that Factor XIa significantly contributes to the generation of thrombin via the intrinsic pathway after the clot has been formed. This additional thrombin, generated inside the clot, was found to protect the clot from fibrinolysis. A plausible mechanism for this inhibitory effect of thrombin involves TAFI (thrombin-activatable fibrinolysis inhibitor, procarboxypeptidase B) which, upon activation, may inhibit fibrinol...

Von Dem Borne, P. A.; Bajzar, L.; Meijers, J. C.; Nesheim, M. E.; Bouma, B. N.

1997-01-01

27

Thrombin has a bimodal effect on glioma cell growth.  

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Using rat glioma C6 cells as a model, we have found a bimodal effect of alpha-thrombin on cell growth. In C6 cells treated with alpha-thrombin at concentrations from 0.02 nM to 1.0 nM, inhibition of cell proliferation was noted. Because the thrombin receptor agonist peptide TRAP-6 also induced inhibition of cell proliferation and the thrombin receptor antagonist peptide T1 prevented the inhibitory effect of alpha-thrombin on C6 glioma cell growth, thrombin receptor involvement in antiprolifer...

Schafberg, H.; Nowak, G.; Kaufmann, R.

1997-01-01

28

A simplified mathematical model for thrombin generation.  

Science.gov (United States)

A new phenomenological mathematical model based directly on laboratory data for thrombin generation and having a patient-specific character is described. A set of the solved equations for cell-based models of blood coagulation that can reproduce the temporal evolution of thrombin generation is proposed; such equations are appropriate for use in computational fluid dynamic (CFD) simulations. The initial values for the reaction rates are either taken from already existing model or experimental data, or they can obtained from simple reasoning under certain assumptions; it is shown that coefficients can be adjusted in order to fit a range of different thrombin generation curves as derived from thrombin generation assays. The behaviour of the model for different platelet concentration seems to be in good agreement with reported experimental data. It is shown that the reduced set of equations used represents to a good approximation a low-order model of the detailed mechanism and thus it can represent a cost-effective and-case specific mathematical model of coagulation reactions up to thrombin generation. PMID:24238617

Papadopoulos, Konstantinos P; Gavaises, Manolis; Atkin, Chris

2014-02-01

29

Characteristics of a new DNA aptamer, direct inhibitor of thrombin.  

Science.gov (United States)

Characteristics of a new antithrombin DNA-aptamer RE31 were studied. This aptamer inhibited thrombin formation in human plasma catalyzed by exogenous (lengthening of thrombin time) and endogenous thrombin (lengthening of partial prothrombin time and activated partial thromboplastin time). In addition, the aptamer completely suppressed thrombin-induced aggregation of human platelets. On the other hand, RE31 did not reduce amidolytic activity of thrombin towards the short peptide substrate, in other words, did not modify the state of enzyme active center. By the capacity to inhibit clotting reactions, RE31 was superior to the previously described highly effective 31-component antithrombin aptamer 31TBA (thrombin binding aptamer, TBA). The effect of RE31 was species-specific: it inhibited human thrombin activity more effectively than activities of rat and rabbit thrombins. PMID:22268033

Mazurov, A V; Titaeva, E V; Khaspekova, S G; Storojilova, A N; Spiridonova, V A; Kopylov, A M; Dobrovolsky, A B

2011-02-01

30

Mechanistic studies on thrombin catalysis.  

Science.gov (United States)

The kinetic mechanism of the cleavage of four p-nitroanilide (pNA) substrates by human alpha-thrombin has been investigated by using a number of steady-state kinetic techniques. Solvent isotope and viscosity effects were used to determine the stickiness of the substrates at the pH optimum of the reaction; a sticky substrate is defined as one that undergoes catalysis faster than it dissociates from the Michaelis complex. Whereas benzoyl-Arg-pNA could be classified as a nonsticky substrate, D-Phe-pipecolyl-Arg-pNA was very sticky. The other two substrates (tosyl-Gly-Pro-Arg-pNA and acetyl-D-Phe-pipecolyl-Arg-pNA) were slightly sticky. The pH profiles of kcat/Km were bell-shaped for all substrates. The pKa values determined from the pH dependence of kcat/Km for benzoyl-Arg-pNA were about 7.5 and 9.1. Similar pKa values were determined from the pH profiles of kcat/Km for tosyl-Gly-Pro-Arg-pNA and acetyl-D-Phe-pipecolyl-Arg-pNA and for the binding of the competitive inhibitor N alpha-dansyl-L-arginine-4-methylpiperidine amide. The groups responsible for the observed pKa values were proposed to be His57 and the alpha-amino group of Ile16. The temperature dependence of the pKa values was consistent with this assignment. The pKa values of 6.7 and 8.6 observed in the pH profile of kcat/Km for D-Phe-pipecolyl-Arg-pNA were displaced to lower values than those observed for the other substrates. The displacement of the acidic pKa value could be attributed to the stickiness of this substrate.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1911776

Stone, S R; Betz, A; Hofsteenge, J

1991-10-15

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Evaluation of the structure–activity relationship of thrombin with thrombin binding aptamers by voltammetry and atomic force microscopy  

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The structure–activity relationship of the complex between thrombin and thrombin binding aptamers (TBA) was evaluated by differential pulse voltammetry at a glassy carbon electrode and atomic force microscopy at a highly oriented pyrolytic graphite electrode. The effects on the interaction with thrombin of TBA primary and secondary structures as well as of its folding properties in the presence of alkaline metals were investigated. The complex between thrombin and single stranded aptamers i...

Diculescu, Victor Constantin; Chiorcea-paquim, Ana-maria; Eritja, Ramon; Oliveira-brett, Ana Maria

2011-01-01

32

pH dependence of the interaction of hirudin with thrombin.  

Science.gov (United States)

The kinetics of the inhibition of human alpha-thrombin by recombinant hirudin have been studied over the pH range from 6 to 10. The association rate constant for hirudin did not vary significantly over this pH range. The dissociation constant of hirudin depended on the ionization state of groups with pKa values of about 7.1, 8.4, and 9.2. Optimal binding of hirudin to thrombin occurred when the groups with pKa values of 8.4 and 9.0 were protonated and the other group with a pKa of 7.1 was deprotonated. The pH kinetics of genetically engineered forms of hirudin were examined in an attempt to assign these pKa values to particular groups. By using this approach, it was possible to show that protonation His51 and ionization of acidic residues in the C-terminal region of hirudin were not responsible for the observed pKa values. In contrast, the pKa value of 8.4 was not observed when a form of hirudin with an acetylated alpha-amino group was examined, and, thus, this pKa value was assigned to the alpha-amino group of hirudin. The requirement for this group to be protonated for optimal binding to thrombin is discussed in terms of the crystal structure of the thrombin-hirudin complex. Examination of this structure allowed the other pKa values of 7.1 and 9.2 to be tentatively attributed to His57 and the alpha-amino group of Ile16 of thrombin. PMID:1734964

Betz, A; Hofsteenge, J; Stone, S R

1992-02-01

33

[Chromatography of thrombin and antithrombin III on biospecific silochromes].  

Science.gov (United States)

It was shown that the seaweed sulfopolysaccharides Furcellaria and Phyllophora--furcellaran and phyllophoran--are the competitive inhibitors of thrombin-induced fibrinogen clotting. Biospecific adsorbents for thrombin and antithrombin III (AT III) isolation were synthesized with heparin, phyllophoran and furcellaran as ligands on aminopropylsilochrome and this proteins sorption characteristics on this sorbents in comparisons with heparin-cellulose and heparin-sepharose were investigated. Possible application of the synthesized adsorbents both for thrombin, AT III purification from blood products and for alpha-thrombin, beta and gamma-thrombin separation are discussed. PMID:9848182

Lohins'ka, Z V; Oryshchenko, N V; Vus, M M; Maherovsky?, Iu V; Ha?da, H Z; Ha?da, A V

1998-01-01

34

Pharmacophore Model Generation of Thrombin Inhibitors  

Directory of Open Access Journals (Sweden)

Full Text Available Thrombin, an important factor of clotting system, take part in a variety of physiological actions, such as blood clotting, anticoagulation, thrombosis and fibrinolysis. Inhibiting thrombin is a pivotal and effective step for the prophylaxis of venous and arterial thrombosis, as well as prevent myocardial infarction for high-risk patients. In this study, a three dimensional pharmacophore model was generated for the molecules which are responsible for vasodilation activities targeting thrombin. Ten compounds with known thrombin-inhibiting activity values were selected as training set to generate the hypothesis using GALAHAD program in SYBYL 7.0 software. The best hypothesis comprises five pharmacophore features: four hydrophobes groups and one positively charged group. It has been further validated towards a test set including known activity compounds obtained from Binding Database, the values of effectively active hit A% and comprehensive evaluation index CAI are respectively 63.33% and 2.34, the pharmacophore was proven to be successful in discriminating active and inactive inhibitors.  Furthermore, the pharmacophore model was used as a 3D query to screen TCMD (Version 2009 database and 6 hit compounds of higher predicted activity were the reported cardiovascular activities, which may be useful for further study.

2013-01-01

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Inhibition of thrombin activity with DNA-aptamers.  

Science.gov (United States)

The effects of two DNA aptamers (oligonucleotides) 15TBA and 31TBA (15- and 31-mer thrombin-binding aptamers, respectively) on thrombin activity were studied. Both aptamers added to human plasma dose-dependently increased thrombin time (fibrin formation upon exposure to exogenous thrombin), prothrombin time (clotting activation by the extrinsic pathway), and activated partial thromboplastin time (clotting activation by the intrinsic pathway). At the same time, these aptamers did not modify amidolytic activity of thrombin evaluated by cleavage of synthetic chromogenic substrate. Aptamers also inhibited thrombin-induced human platelet aggregation. The inhibitory effects of 31TBA manifested at lower concentrations than those of 15TBA in all tests. These data indicate that the studied antithrombin DNA aptamers effectively suppress its two key reactions, fibrin formation and stimulation of platelet aggregation, without modifying active center of the thrombin molecule. PMID:19902090

Dobrovolsky, A B; Titaeva, E V; Khaspekova, S G; Spiridonova, V A; Kopylov, A M; Mazurov, A V

2009-07-01

36

Hemalin, a thrombin inhibitor isolated from a midgut cDNA library from the hard tick Haemaphysalis longicornis.  

Science.gov (United States)

A full-length sequence of a thrombin inhibitor (designated as hemalin) from the midgut of parthenogenetic Haemaphysalis longicornis has been identified. Sequence analysis shows that this gene belongs to the Kunitz-type family, containing two Kunitz domains with high homology to boophilin, the thrombin inhibitor from Rhipicephalus (Boophilus) microplus. The recombinant protein expressed in insect cells delayed bovine plasma clotting time and inhibited both thrombin-induced fibrinogen clotting and platelet aggregation. A 20-kDa protein was detected from the midgut lysate with antiserum against recombinant hemalin. The gene is expressed at all stages of the tick except for the egg stage, and hemalin mRNA mainly in the midgut of the female adult tick. Real-time PCR analysis shows that this gene has a distinctly high expression level in the rapid bloodsucking period of the larvae, nymphs, and adults. Disruption of the hemalin gene by RNA interference led to a 2-day extension of the tick blood feeding period, and 27.7% of the RNA-treated ticks did not successfully complete the blood feeding. These findings indicate that the newly identified thrombin inhibitor from the midgut of H. longicornis might play an important role in tick blood feeding. PMID:19061894

Liao, Min; Zhou, Jinlin; Gong, Haiyan; Boldbaatar, Damdinsuren; Shirafuji, Rika; Battur, Banzragch; Nishikawa, Yoshifumi; Fujisaki, Kozo

2009-02-01

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Fibrinogen and thrombin concentrations are critical for fibrin glue adherence in rat high-risk colon anastomoses  

Science.gov (United States)

OBJECTIVE: Fibrin glues have not been consistently successful in preventing the dehiscence of high-risk colonic anastomoses. Fibrinogen and thrombin concentrations in glues determine their ability to function as sealants, healers, and/or adhesives. The objective of the current study was to compare the effects of different concentrations of fibrinogen and thrombin on bursting pressure, leaks, dehiscence, and morphology of high-risk ischemic colonic anastomoses using fibrin glue in rats. METHODS: Colonic anastomoses in adult female Sprague-Dawley rats (weight, 250-350 g) treated with fibrin glue containing different concentrations of fibrinogen and thrombin were evaluated at post-operative day 5. The interventions were low-risk (normal) or high-risk (ischemic) end-to-end colonic anastomoses using polypropylene sutures and topical application of fibrinogen at high (120 mg/mL) or low (40 mg/mL) concentrations and thrombin at high (1000 IU/mL) or low (500 IU/mL) concentrations. RESULTS: Ischemia alone, anastomosis alone, or both together reduced the bursting pressure. Glues containing a low fibrinogen concentration improved this parameter in all cases. High thrombin in combination with low fibrinogen also improved adherence exclusively in low-risk anastomoses. No differences were detected with respect to macroscopic parameters, histopathology, or hydroxyproline content at 5 days post-anastomosis. CONCLUSIONS: Fibrin glue with a low fibrinogen content normalizes the bursting pressure of high-risk ischemic left-colon anastomoses in rats at day 5 after surgery.

Buen, Eliseo Portilla-de; Orozco-Mosqueda, Abel; Leal-Cortes, Caridad; Vazquez-Camacho, Gonzalo; Fuentes-Orozco, Clotilde; Alvarez-Villasenor, Andrea Socorro; Macias-Amezcua, Michel Dassaejv; Gonzalez-Ojeda, Alejandro

2014-01-01

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Thrombin regulates the function of human blood dendritic cells  

International Nuclear Information System (INIS)

Thrombin is the key enzyme in the coagulation cascade and activates endothelial cells, neutrophils and monocytes via protease-activated receptors (PARs). At the inflammatory site, immune cells have an opportunity to encounter thrombin. However little is known about the effect of thrombin for dendritic cells (DC), which are efficient antigen-presenting cells and play important roles in initiating and regulating immune responses. The present study revealed that thrombin has the ability to stimulate blood DC. Plasmacytoid DC (PDC) and myeloid DC (MDC) isolated from PBMC expressed PAR-1 and released MCP-1, IL-10, and IL-12 after thrombin stimulation. Unlike blood DC, monocyte-derived DC (MoDC), differentiated in vitro did not express PAR-1 and were unresponsive to thrombin. Effects of thrombin on blood DC were significantly diminished by the addition of anti-PAR-1 Ab or hirudin, serine protease inhibitor. Moreover, thrombin induced HLA-DR and CD86 expression on DC and the thrombin-treated DC induced allogenic T cell proliferation. These findings indicate that thrombin plays a role in the regulation of blood DC functions

2007-12-14

39

Thrombin-induced increase in albumin permeability across the endothelium  

International Nuclear Information System (INIS)

We studied the effect of thrombin on albumin permeability across the endothelial monolayer in vitro. Bovine pulmonary artery endothelial cells were grown on micropore membranes. Morphologic analysis confirmed the presence of a confluent monolayer with interendothelial junctions. Albumin permeability was measured by the clearance of 125I-albumin across the endothelial monolayer. The control 125I-albumin clearance was 0.273 +/- 0.02 microliter/min. The native enzyme, alpha-thrombin (10(-6) to 10(-10) M), added to the luminal side of the endothelium produced concentration-dependent increases in albumin clearance (maximum clearance of 0.586 +/- 0.08 microliter/min at 10(-6) M). Gamma (gamma) thrombin (10(-6) M and 10(-8) M), which lacks the fibrinogen recognition site, also produced a concentration-dependent increase in albumin clearance similar to that observed with alpha-thrombin. Moreover, the two proteolytically inactive forms of the native enzyme, i-Pr2 P-alpha-thrombin and D-Phe-Pro-Arg-CH2-alpha-thrombin, increased the 125I-albumin clearance (0.610 +/- 0.09 microliter/min and 0.609 +/- 0.02 microliter/min for i-Pr2 P-alpha-thrombin and D-Phe-Pro-Arg-CH2-alpha-thrombin at 10(-6) M, respectively). Since the modified forms of thrombin lack the fibrinogen recognition and active serine protease sites, the results indicate that neither site is required for increased albumin permeability. The increase in albumin clearance with alpha-thrombin was not secondary to endothelial cell lysis because lactate dehydrogenase concentration in the medium following thrombin was not significantly different from baseline values. There was also no morphological evidence of cell lysis. Moreover, the increase in 125I-albumin clearance induced by alpha-thrombin was reversible by washing thrombin from the endothelium

1986-01-01

40

Role of thrombin exosites in inhibition by heparin cofactor II.  

Science.gov (United States)

We determined the role of specific thrombin "exosites" in the mechanism of inhibition by the plasma serine proteinase inhibitors heparin cofactor II (HC) and antithrombin (AT) in the absence and presence of a glycosaminoglycan by comparing the inhibition of alpha-thrombin to epsilon- and gamma T-thrombin (produced by partial proteolysis of alpha-thrombin by elastase and trypsin, respectively). All of the thrombin derivatives were inhibited in a similar manner by AT, either in the absence or presence of heparin, which confirmed the integrity of both heparin binding abilities and serpin reactivities of epsilon- and gamma T-thrombin compared to alpha-thrombin. Antithrombin activities of HC in the absence of a glycosaminoglycan with alpha-, epsilon, and gamma T-thrombin were similar with rate constants of 3.5, 2.4, and 1.2 x 10(4) M-1 min-1, respectively. Interestingly, in the presence of glycosaminoglycans the maximal inhibition rate constants by HC with heparin and dermatan sulfate, respectively, were as follows: 30.0 x 10(7) and 60.5 x 10(7) for alpha-thrombin, 14.6 x 10(7) and 24.3 x 10(7) for epsilon-thrombin, and 0.017 x 10(7) and 0.034 x 10(7) M-1 min-1 for gamma T-thrombin. A hirudin carboxyl-terminal peptide, which binds to anion-binding exosite-I of alpha-thrombin, dramatically reduced alpha-thrombin inhibition by HC in the presence of heparin but not in its absence. We analyzed our results in relation to the recently determined x-ray structure of D-Phe-Pro-Arg-chloromethyl ketone-alpha-thrombin (Bode, W., Mayr, I., Baumann, U., Huber, R., Stone, S. R., and Hofsteenge, J. (1989) EMBO J. 8, 3467-3475). Our results suggest that the beta-loop region of anion-binding exosite-I in alpha-thrombin, which is not present in gamma T-thrombin, is essential for the rapid inhibition reaction by HC in the presence of a glycosaminoglycan. Therefore, alpha-thrombin and its derivatives would be recognized and inhibited differently by HC and AT in the presence of a glycosaminoglycan. PMID:1740413

Rogers, S J; Pratt, C W; Whinna, H C; Church, F C

1992-02-25

 
 
 
 
41

Thrombin and brain recovery after intracerebral hemorrhage  

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Intracerebral hemorrhage (ICH) is a common and often fatal subtype of stroke and produces severe neurological deficits in survivors. At present, there is lack of effective treatments that improve outcome in ICH. A neglected aspect of ICH research is the development of approaches that can be effectively used to improve recovery. Although previous studies have showed that thrombin induces blood-brain barrier leakage, brain edema and neuronal death after intracerebral hemorrhage (ICH), our recen...

Hua, Ya; Keep, Richard F.; Gu, Yuxiang; Xi, Guohua

2009-01-01

42

Thrombin Injection for Acute Hemorrhage Following Angiography  

International Nuclear Information System (INIS)

Femoral arterial puncture is the main access for diagnostic and therapeutic intervention in vascular disease. Significant complications are unusual and include uncontrolled bleeding which usually requires surgery. We report the use of ultrasound-guided thrombin injection that prevented any immediate need for surgery in 2 cases of uncontrolled bleeding following femoral arteriography. Clinical presentations and treatment are reported, together with a review of the literature

2007-07-01

43

Headache Topics  

Science.gov (United States)

Home » My Headache » Headache Topic Sheets Headache Topic Sheets Consumer Topics Consumer Medications Spanish Abdominal Migraine Acupuncture Alcohol and Headaches Allergy and Headaches Analgesic Rebound Anemia Arteriovenous Malformation Arthritis Aura Basilar ...

44

Thrombin induces endothelial arginase through AP-1 activation  

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Arterial thrombosis is a common disease leading to severe ischemia beyond the obstructing thrombus. Additionally, endothelial dysfunction at the site of thrombosis can be rescued by l-arginine supplementation or arginase blockade in several animal models. Exposure of rat aortic endothelial cells (RAECs) to thrombin upregulates arginase I mRNA and protein levels. In this study, we further investigated the molecular mechanism of thrombin-induced arginase changes in endothelial cells. Thrombin s...

Zhu, Weifei; Chandrasekharan, Unni M.; Bandyopadhyay, Smarajit; Morris, Sidney M.; Dicorleto, Paul E.; Kashyap, Vikram S.

2010-01-01

45

Thrombin generation in different cohorts : Evaluation of the haemostatic potential  

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The aim of this thesis is to evaluate thrombin generation in patients with thrombophilia (Paper I), in patients with venous thromboembolism (Paper II), in healthy women during the menstrual cycle (Paper III), in patients with liver disease (Paper IV) and in patients with mild deficiency of factor VII (Paper V). For this purpose, thrombin generation was measured in platelet poor plasma by the calibrated automated thrombogram (CAT®) assay. Thrombin generation expresses the overall haemostatic ...

Chaireti, Roza

2013-01-01

46

Thrombin-mediated impairment of fibroblast growth factor-2 activity.  

Science.gov (United States)

Thrombin generation increases in several pathological conditions, including cancer, thromboembolism, diabetes and myeloproliferative syndromes. During tumor development, thrombin levels increase along with several other molecules, including cytokines and angiogenic factors. Under such conditions, it is reasonable to predict that thrombin may recognize new low-affinity substrates that usually are not recognized under low-expression levels conditions. In the present study, we hypothesized that fibroblast growth factor (FGF)-2 may be cleaved by thrombin and that such action may lead to an impairment of its biological activity. The evidence collected in the present study indicates that FGF-2-induced proliferation and chemotaxis/invasion of SK-MEL-110 human melanoma cells were significantly reduced when FGF-2 was pre-incubated with active thrombin. The inhibition of proliferation was not influenced by heparin. Phe-Pro-Arg-chloromethyl ketone, a specific inhibitor of the enzymatic activity of thrombin, abolished the thrombin-induced observed effects. Accordingly, both FGF-2-binding to cell membranes as well as FGF-2-induced extracellular signal-regulated kinase phosphorylation were decreased in the presence of thrombin. Finally, HPLC analyses demonstrated that FGF-2 is cleaved by thrombin at the peptide bond between residues Arg42 and Ile43 of the mature human FGF-2 sequence. The apparent k(cat)/K(m) of FGF-2 hydrolysis was 1.1 x 10(4) M(-1) x s(-1), which is comparable to other known low-affinity thrombin substrates. Taken together, these results demonstrate that thrombin digests FGF-2 at the site Arg42-Ile43 and impairs FGF-2 activity in vitro, indicating that FGF-2 is a novel thrombin substrate. PMID:19438723

Totta, Pierangela; De Cristofaro, Raimondo; Giampietri, Claudia; Aguzzi, Maria S; Faraone, Debora; Capogrossi, Maurizio C; Facchiano, Antonio

2009-06-01

47

Contribution of the N-terminal region of hirudin to its interaction with thrombin.  

Science.gov (United States)

Hirudin is a 65-residue polypeptide that specifically inhibits thrombin by forming a tight, noncovalent complex with the enzyme. The role of the two amino-terminal valine residues and the N-terminal alpha-amino group of hirudin in the formation of the complex has been investigated by site-directed mutagenesis and chemical modification. Replacement of the two N-terminal valyl residues of recombinant hirudin by polar amino acids resulted in an increase in the inhibition constant (KI). In contrast, replacement of these residues by hydrophobic amino acids had little effect on the value for KI. These results demonstrated that the hydrophobic nature of the N-terminal residues of hirudin was important for its interaction with thrombin. Addition of a single amino acid to the N-terminus of hirudin resulted in a marked increase in the value of KI. A similar effect was observed when the positive charge of the alpha-amino group was removed by acetylation. In contrast, amidination of this group, which preserves the positive charge, resulted in a less pronounced increase in the value of KI. Thus, it appears that a positive charge immediately adjacent to the N-terminal hydrophobic residue is required for optimal binding to thrombin. PMID:2620063

Wallace, A; Dennis, S; Hofsteenge, J; Stone, S R

1989-12-26

48

Intrinsic fluorescence changes and rapid kinetics of the reaction of thrombin with hirudin.  

Science.gov (United States)

Stopped-flow fluorescence spectroscopy has been used to study the reaction of human alpha-thrombin with recombinant hirudin variant 1 (rhir) at 37 degrees C and an ionic strength of 0.125 M. A 35% enhancement in intrinsic fluorescence accompanied formation of the thrombin-rhir complex. Over one third of this enhancement corresponded to a structural change that could be induced by binding of either the NH2-terminal fragment (residues 1-51) or the COOH-terminal fragment (residues 52-65) of rhir. Three kinetic steps were detected for reaction of thrombin with rhir. At high rhir concentrations (greater than or equal to 3 microM), two intramolecular steps with observed rate constants of 296 +/- 5 s-1 and 50 +/- 1 s-1 were observed. By using the COOH-terminal fragment of rhir as a competitive inhibitor, it was possible to obtain an estimate of 2.9 x 10(8) M-1 s-1 for the effective association rate constant at low rhir concentrations. At higher ionic strengths, this rate constant was lower, which is consistent with the formation of the initial complex involving an ionic interaction. The mechanism for the reaction of both the COOH- and NH2-terminal fragments of rhir appeared to involve two steps. When thrombin was reacted with the COOH-terminal fragment at high concentrations (greater than or equal to 6 microM), the bimolecular step occurred within the dead time of the spectrometer and only one intramolecular step, with a rate constant of 308 +/- 5 s-1 was observed. At concentrations of NH2-terminal fragment below 50 microM, its binding to thrombin appeared to be a bimolecular reaction with an association rate constant of 8.3 x 10(5) M-1 s-1. In the presence of saturating concentrations of the COOH-terminal fragment, a 1.7-fold increase in this rate constant was observed. At concentrations of NH2-terminal fragment greater than 50 microM, biphasic reaction traces were observed which suggests a two-step mechanism. By comparing the reaction amplitudes and dissociation constants observed with rhir and its COOH-terminal fragment, it was possible to obtain approximate estimates for the values of the rate constants of different steps in the formation of the rhir-thrombin complex. PMID:1639783

Jackman, M P; Parry, M A; Hofsteenge, J; Stone, S R

1992-08-01

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Human Thrombin Injection for the Percutaneous Treatment of Iatrogenic Pseudoaneurysms  

International Nuclear Information System (INIS)

Purpose: Thrombin injection is becoming well established for the percutaneous management of iatrogenic pseudoaneurysms. All the published series to date use bovine thrombin,and there have been reports of adverse immunologic effects following its use. Our study aimed to assess the efficacy of human thrombin injection for pseudoaneurysm occlusion. Methods:Fourteen patients with iatrogenic pseudoaneurysms underwent a color Doppler ultrasound examination to assess their suitability for percutaneous human thrombin injection. Human thrombin 1000 IU was then injected into the pseudoaneurysm sac under sterile conditions and with ultrasound guidance. A further color Doppler ultrasound examination was performed 24 hr later to confirm occlusion. Results: All 14 pseudoaneurysms were successfully occluded by human thrombin injection. In two cases a second injection of thrombin was required,but there were no other complications, and all pseudoaneurysms remained occluded at 24 hr. Conclusion: Ultrasound-guided human thrombin injection is simple to perform, effective and safe. We recommend that human thrombin becomes the agent of choice for percutaneous injection into iatrogenic pseudoaneurysms

2002-03-01

50

Early detection of thrombin activity in neuroinflammatory disease.  

Science.gov (United States)

Although multiple sclerosis (MS) has been associated with the coagulation system, the temporal and spatial regulation of coagulation activity in neuroinflammatory lesions is unknown. Using a novel molecular probe, we characterized the activity pattern of thrombin, the central protease of the coagulation cascade, in experimental autoimmune encephalomyelitis. Thrombin activity preceded onset of neurological signs, increased at disease peak, and correlated with fibrin deposition, microglial activation, demyelination, axonal damage, and clinical severity. Mice with a genetic deficit in prothrombin confirmed the specificity of the thrombin probe. Thrombin activity might be exploited for developing sensitive probes for preclinical detection and monitoring of neuroinflammation and MS progression. PMID:24740641

Davalos, Dimitrios; Baeten, Kim M; Whitney, Michael A; Mullins, Eric S; Friedman, Beth; Olson, Emilia S; Ryu, Jae Kyu; Smirnoff, Dimitri S; Petersen, Mark A; Bedard, Catherine; Degen, Jay L; Tsien, Roger Y; Akassoglou, Katerina

2014-02-01

51

Allosteric networks in thrombin distinguish procoagulant vs. anticoagulant activities  

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The serine protease ?-thrombin is a dual-action protein that mediates the blood-clotting cascade. Thrombin alone is a procoagulant, cleaving fibrinogen to make the fibrin clot, but the thrombin–thrombomodulin (TM) complex initiates the anticoagulant pathway by cleaving protein C. A TM fragment consisting of only the fifth and sixth EGF-like domains (TM56) is sufficient to bind thrombin, but the presence of the fourth EGF-like domain (TM456) is critical to induce the anticoagulant activity ...

Gasper, Paul M.; Fuglestad, Brian; Komives, Elizabeth A.; Markwick, Phineus R. L.; Mccammon, J. Andrew

2012-01-01

52

Human umbilical vein smooth muscle cells as a model to study thrombin generation and function: effect of thrombin inhibitors.  

Science.gov (United States)

The aim of the present work was to study how human umbilical vein smooth muscle cells (HUVSMC) can initiate the coagulation process and to investigate the responses of these cells to thrombin. Exposure of HUVSMC to recalcified human plasma led to a time-dependent production of thrombin, measured both as amidolytic activity and as release of fibrinopeptide A. Thrombin activity was dose-dependently reduced by an anti-human tissue factor antibody (76 +/- 3% at 10 micrograms/ml) and by inhibitors like heparin, rec-hirudin, hirulog 1, Napap and hirunorm, a novel hirudin-like thrombin inhibitor (IC50 = 2 +/- 0.4, 8 +/- 1, 130 +/- 22, 199 +/- 29 and 68 +/- 8 nM, respectively). The release of fibrinopeptide A was similarly prevented (IC50 = 14 +/- 1, 132 +/- 25 and 50 +/- 8 nM for rec-hirudin, Napap and hirunorm, respectively). Exogenously added thrombin increased thymidine incorporation into HUVSMC to 240 +/- 30% of basal (EC50 = 0.49 +/- 0.09 nM) and thrombin inhibitors blocked this effect (IC50 = 10 +/- 3, 37 +/- 17, 343 +/- 165 and 1402 +/- 758 nM for rec-hirudin, hirunorm, Napap and hirulog-1, respectively). Also recalcified human plasma was mitogenic for HUVSMC and its effect was mainly due to endogenously generated thrombin, as shown by the use of thrombin inhibitors. In conclusion, HUVSMC are capable of initiating the extrinsic coagulation cascade, leading to the formation of thrombin which promotes clotting and stimulates DNA synthesis. Thrombin inhibitors prevent both coagulative and cellular effects of thrombin. PMID:8903003

Catalioto, R M; Cucchi, P; Renzetti, A R; Criscuoli, M; Subissi, A

1996-10-01

53

A thrombin receptor in resident rat peritoneal macrophages  

International Nuclear Information System (INIS)

Resident rat peritoneal macrophages possess 6 x 10(2) high-affinity binding sites per cell for bovine thrombin with a Kd of 11 pM, and 7.5 x 10(4) low-affinity sites with a Kd of 5.8 nM. These binding sites are highly specific for thrombin. Half-maximal binding of 125I-labeled bovine thrombin is achieved after 1 min at 37 degrees C, and after 12 min at 4 degrees C. The reversibly bound fraction of the ligand dissociates according to a biexponential time course with the rate constants 0.27 and 0.06 min-1 at 4 degrees C. Part of the tracer remains cell-associated even after prolonged incubation, but all cell-associated radio-activity migrates as intact thrombin upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The bound thrombin is minimally endocytosed as judged by the resistance to pH 3 treatment, and the receptor does not mediate a quantitatively important degradation of the ligand. The binding is not dependent on the catalytic site of thrombin, since irreversibly inactivated thrombin also binds to the receptor. 125I-labeled thrombin covalently cross-linked to its receptor migrates in sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a Mr 160,000, corresponding to an approximate receptor size of Mr 120,000

1991-01-01

54

Mechanisms of platelet activation by thrombin: a short history.  

Science.gov (United States)

Platelet activation by thrombin is relevant to arterial thrombosis, therefore it is an attractive target for the development of new antithrombotic drugs. In the 1970s the platelet membrane complex glycoprotein (GP) Ib-V-IX was shown to have a high affinity binding site for thrombin on GPIb? and a substrate cleaved by thrombin, GPV. For several years it was considered to be involved in platelet activation by thrombin. The discovery of the protease activated receptors (PARs) in 1991 was a major breakthrough in the field. The first member of this family of receptors to be discovered was PAR1, a seven transmembrane G-protein coupled receptor which, upon cleavage by thrombin, unmasks a new amino-terminus able to bind intramolecularly to PAR1 itself thus inducing signaling. On human platelets PAR1 and, later PAR4, were demonstrated to mediate most of the platelet responses to thrombin. However, after the discovery of PARs, different groups demonstrated that GPIb? is required to stimulate a full platelet activation by thrombin. A model where thrombin binds to the GPIb receptor prior to proteolysis of the PAR receptors was supported by several lines of evidence. A role for GPV as inhibitor of GPIb? signaling has been shown by using GPV knock-out mice. Crystallographic data suggested that thrombin bound to GPIb? might be able to interact with other GPIb? molecules on the same or other platelets, shedding light on a new role for thrombin binding to GPIb?. Finally, anti-PAR1 molecules were developed which are now in phase II and III clinical studies as antithrombotic drugs. PMID:22137742

De Candia, Erica

2012-03-01

55

Fluorouracil Topical  

Science.gov (United States)

Fluorouracil cream and topical solution are used to treat actinic or solar keratoses (scaly or crusted lesions [ ... by years of too much exposure to sunlight). Fluorouracil cream and topical solution are also used to ...

56

Towards a standardization of thrombin generation assessment: The influence of tissue factor, platelets and phospholipids concentration on the normal values of Thrombogram-Thrombinoscope assay  

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Full Text Available Abstract Background Thrombin generation assay was developed several years ago to mimic physiological coagulation mechanisms but it had important limitations. Thrombogram-Thrombinoscope assay using a fluorogenic substrate, allows obtaining thrombin generation curves in non-defibrinated platelet rich plasma (PRP in a fully automated manner. Methods We standardised the methodology of Thrombogram-Thrombinoscope and we evaluated the precision of thrombin generation parameters (lag-time, maximum concentration of thrombin [Cmax], time required to reach Cmax [Tmax] and endogenous thrombin potential ETP using different concentrations of recombinant human tissue factor, platelets or phospholipids. Normal values of thrombin generation assay were established in optimal experimental conditions. Results In the presence of low TF concentrations (final dilution of thromboplastin in plasma: 1/1000–1/2000 the Thrombogram assay showed intra-assay and inter-assay coefficients of variation lower than 9%. Thrombin generation parameters showed an important inter-individual variability and the coefficients of variation ranged from 18% to 50%. In PRP the lag-time, Cmax and Tmax but not the ETP, were influenced by TF concentration. Thrombin generation parameters were not influenced by variations of platelet concentration from 50 × 109/l to 400 × 109/l. The addition of synthetic procoagulant phospholipids in PPP strongly influenced all the parameters of thrombogram. For all the parameters of thrombogram a threshold effect was observed in the presence of phspholipid concentrations equal or higher to 4 ?M. In frozen-thawed PRP the lag-time and the Tmax were significantly reduced and the Cmax was increased compared to the fresh PRP, but the ETP, the intra assay and the inter-assay coefficients of variation were similar in both test-systems. Conclusion Thrombogram-Thrombinoscope assay performed in fresh or in frozen-thawed PRP has an acceptable precision, with low inter-assay and intra-assay coefficient of variations. The concentration of TF is determinant for the normal values of the studied parameters of thrombin generation. When the assay is performed in PPP, thrombin generation parameters are influenced by the concentration of procoagulant synthetic phospholipids. The optimal experimental conditions were obtained in the presence of 1/1000 final dilution of thromboplastin, a platelet count higher than 50 × 109/l and a synthetic phospholipid concentration higher than 4 ?M.

Leflem Lena

2005-10-01

57

Planar Hall magnetoresistive aptasensor for thrombin detection.  

Science.gov (United States)

The use of aptamer-based assays is an emerging and attractive approach in disease research and clinical diagnostics. A sensitive aptamer-based sandwich-type sensor is presented to detect human thrombin using a planar Hall magnetoresistive (PHR) sensor in cooperation with superparamagnetic labels. A PHR sensor has the great advantages of a high signal-to-noise ratio, a small offset voltage and linear response in the low-field region, allowing it to act as a high-resolution biosensor. In the system presented here, the sensor has an active area of 50µm×50µm with a 10-nm gold layer deposited onto the sensor surface prior to the binding of thiolated DNA primary aptamer. A polydimethylsiloxane well of 600-µm radius and 1-mm height was prepared around the sensor surface to maintain the same specific area and volume for each sensor. The sensor response was traced in real time upon the addition of streptavidin-functionalized magnetic labels on the sensor. A linear response to the thrombin concentration in the range of 86pM-8.6µM and a lower detection limit down to 86pM was achieved by the proposed present method with a sample volume consumption of 2µl. The proposed aptasensor has a strong potential for application in clinical diagnosis. PMID:24727201

Sinha, B; Ramulu, T S; Kim, K W; Venu, R; Lee, J J; Kim, C G

2014-09-15

58

Interaction of the N-terminal region of hirudin with the active-site cleft of thrombin.  

Science.gov (United States)

Site-specific substitutions of the first five amino acids of the thrombin inhibitor hirudin have been made and the effects of these substitutions on the kinetics of formation of the thrombin-hirudin complex evaluated. The effects of different substitutions of Val1 indicate that nonpolar interactions play a major role in the binding of this residue. In the second position (Val2), polar amino acids were better accommodated than in the first. The mutant with arginine in the second position bound particularly well to thrombin; its dissociation constant was 9-fold lower than that of wild-type recombinant hirudin. Comparison of the effects of single and double mutations involving Val1 and Val2 indicates that there was no cooperativity in the binding of these two residues. Elimination of the hydrophobic interactions made by the aromatic ring of Tyr3 of hirudin resulted in a large loss of binding energy (12.7 kJ mol-1). Replacement of Thr4 of hirudin by serine and alanine suggested that both the gamma-methyl and the hydroxyl group of the threonine were important in the stabilization of the thrombin-hirudin complex. Replacement of Asp5 of hirudin by alanine and glutamate caused about the same loss in binding energy (5 kJ mol-1). The effects of site-specific substitutions are discussed in terms of the crystal structure of the thrombin-hirudin complex. Molecular modeling provided plausible explanations for many of the observed effects. For instance, such studies suggested that the improved binding of the mutant with arginine in the second position could be due to an interaction of the arginine with the primary specificity pocket. PMID:1581311

Betz, A; Hofsteenge, J; Stone, S R

1992-05-19

59

APTAMER-BASED SERRS SENSOR FOR THROMBIN DETECTION  

Energy Technology Data Exchange (ETDEWEB)

We describe an aptamer-based Surface Enhanced Resonance Raman Scattering (SERRS) sensor with high sensitivity, specificity, and stability for the detection of a coagulation protein, human a-thrombin. The sensor achieves high sensitivity and a limit of detection of 100 pM by monitoring the SERRS signal change upon the single step of thrombin binding to immobilized thrombin binding aptamer. The selectivity of the sensor is demonstrated by the specific discrimination of thrombin from other protein analytes. The specific recognition and binding of thrombin by the thrombin binding aptamer is essential to the mechanism of the aptamer-based sensor, as shown through measurements using negative control oligonucleotides. In addition, the sensor can detect 1 nM thrombin in the presence of complex biofluids, such as 10% fetal calf serum, demonstrating that the immobilized, 5{prime}-capped, 3{prime}-capped aptamer is sufficiently robust for clinical diagnostic applications. Furthermore, the proposed sensor may be implemented for multiplexed detection using different aptamer-Raman probe complexes.

Cho, H; Baker, B R; Wachsmann-Hogiu, S; Pagba, C V; Laurence, T A; Lane, S M; Lee, L P; Tok, J B

2008-07-02

60

Label-free impedimetric biosensor for thrombin using the thrombin-binding aptamer as receptor  

International Nuclear Information System (INIS)

This study presents the further establishment of impedimetric biosensors with aptamers as receptors. Aptamers are short single-stranded oligonucleotides which bind analytes with a specific region of their 3D structure. Electrical impedance spectroscopy is a sensitive method for analyzing changes on the electrode surface, e.g. caused by receptor-ligand-interactions. Fast and inexpensive prototyping of electrodes on the basis of commercially available compact discs having a 24 carat gold reflective layer was investigated. Electrode structures (CDtrodes [1]) in the range from few millimetres down to 100 microns were realized. The well-studied thrombin-binding aptamer (TBA) was used as receptor for characterizing these micro- and macro-electrodes. The impedance signal showed a linear correlation for concentrations of thrombin between 1.0 nM to 100 nM. This range corresponds well with most of the references and may be useful for the point-of-care testing (POCT).

2013-04-18

 
 
 
 
61

Thrombin activatable fibrinolysis inhibitor and thrombin-antithrombin-III-complex levels in patients with gastric cancer.  

Science.gov (United States)

The relation between cancer and coagulation is the subject of investigation since a relation between tumor and thrombosis has been determined. Antithrombin III is an important thrombin inhibitor, and increased thrombin-antithrombin (TAT) complex levels activate coagulation. Activated thrombin activatable fibrinolysis inhibitor (TAFI) inhibits the conversion of plasminogen to plasmin. In addition, it directly inactivates plasmin. Defective fibrinolysis increases the risk of thrombosis. In this study, we evaluated homeostatic parameters, TAFI, and TAT levels in patients with gastric cancer applying to the medical oncology outpatient clinic. Fifty-two patients and 35 healthy controls were included. ELISA was used to measure TAFI and TAT complex levels. These were statistically higher in the patient group (p cancer. This situation is due to the impairment of the balance between coagulation and fibrinolysis. Further studies are now needed to evaluate the effects of TAFI and TAT on survey and prognosis as well as the potential of these parameters as tumor markers for gastric cancer. PMID:22535370

Fidan, Evren; Kavgaci, Halil; Orem, Asim; Yilmaz, Mustafa; Yildiz, Bulent; Fidan, Sami; Akcan, Buket; Ozdemir, Feyyaz; Aydin, Fazil

2012-10-01

62

The effect of thrombin on a 6-hydroxydopamine model of Parkinson's disease depends on timing  

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Recent results in animal models suggest that thrombin may modulate brain injury in Parkinson's disease (PD). High doses of thrombin (?20 U) can damage dopaminergic neurons, while we have found that low dose thrombin (1 U), given several days before a brain insult (thrombin preconditioning), is protective in models of PD and stroke. However, the effects of such low levels of thrombin at the time of, or after, exposure to the dopamine neurotoxin 6-hydroxydopamine (6-OHDA) have not been examin...

Cannon, Jason R.; Hua, Ya; Richardson, Rudy J.; Xi, Guohua; Keep, Richard F.; Schallert, Timothy

2007-01-01

63

Disparate temporal expression of the prothrombin and thrombin receptor genes during mouse development.  

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The protease thrombin is a potent agonist for platelet aggregation, mesenchymal cell proliferation, and endothelial production of growth factors and adhesion molecules. Thrombin also modulates neurite outgrowth in neuronal cultures. These apparently disparate responses to thrombin appear to be largely mediated by the recently cloned thrombin receptor. In the adult, thrombin is generated from its zymogen prothrombin at sites of vascular injury when circulating coagulation factors meet extravas...

Soifer, S. J.; Peters, K. G.; O Keefe, J.; Coughlin, S. R.

1994-01-01

64

Antithrombotic effects of bromophenol, an alga-derived thrombin inhibitor  

Science.gov (United States)

Thrombin, the ultimate proteinase of the coagulation cascade, is an attractive target for the treatment of a variety of cardiovascular diseases. A bromophenol derivative named (+)-3-(2,3-dibromo-4, 5-dihydroxy-phenyl)-4-bromo-5,6-dihydroxy-1,3-dihydroiso-benzofuran 1, isolated from the brown alga Leathesia nana exhibited significant thrombin inhibitory activity. In this study, we investigated the inhibition of human thrombin in vitro with this bromophenol derivative, and its antithrombotic efficacy in vivo using the arteriovenous shunt model and the ferric chloride-induced arterial thrombosis model in rats. The results show that the bromophenol derivative is a potential inhibitor of thrombin (IC50=1.03 nmol/L). In antithrombotic experiments in vivo, the bromophenol derivative also shows good effect comparing with the control group. These data indicate that the bromophenol derivative is a potential drug for prophylaxis and the treatment of thrombotic diseases.

Shi, Dayong; Li, Xiaohong; Li, Jing; Guo, Shuju; Su, Hua; Fan, Xiao

2010-01-01

65

Exogenous bovine thrombin as a biomarker of exposure and outcome.  

Science.gov (United States)

Bovine thrombin has been used for more than 60 years as a surgical hemostat and sealant. Rare postsurgical events have been attributed to antibovine thrombin immunoglobulins cross-reacting with human homologs. In a literature review of 37 papers reporting safety outcomes in surgical patients, we extracted each paper for a quantitative measurement of bovine thrombin exposure and coagulopathic outcomes. We found that 59.5% of papers documented the commercial source of bovine thrombin and only 19% provided an estimate of exposure in units. Conventional tests for hypocoagulation were common (86%); however, only 9% of papers confirmed this inhibition as an isolated antibody. In addition, only 9% of papers cited a specific biomarker for thrombosis. PMID:18785812

Crean, Sheila M; Michels, Shannon L; Reynolds, Matthew W

2008-09-01

66

Aptamer-based thrombin assay on microfluidic platform.  

Science.gov (United States)

A facile and sensitive aptamer-based protocol has been developed for protein assay on microfluidic platform with fluorescence detection using an off-chip microarray scanner. Aptamer-functionalized magnetic beads were used to capture thrombin that binds to a second aptamer fluorescently labeled by Cy3. Experimental conditions, such as incubation time and temperature, washing time, interfering proteins, and aptamer, etc., were optimized for the microchip method. This work demonstrated there was a good relationship between fluorescence intensity and thrombin concentration in the range of 65-1000 ng/mL with the RSD less than 8%. Notably, an analysis only needs 1 ?L volume of sample injection and this system can capture extremely tiny amount thrombin (0.4 fmol). This method has been successfully applied to assay of thrombin in human serum with the recovery of 79.74-95.94%. PMID:24127412

Chen, Fang-Yuan; Wang, Zheng; Li, Peng; Lian, Hong-Zhen; Chen, Hong-Yuan

2013-12-01

67

Endovascular Thrombin Injection for a Pulmonary Artery Pseudoaneurysm: Case Report  

Energy Technology Data Exchange (ETDEWEB)

Massive hemoptysis caused by pulmonary artery pseudoaneurysms is uncommon, and endovascular treatment such as coil embolization is the first choice for treating pulmonary artery pseudoaneurysms. Various embolic agents could be used according to the angiographic findings, yet embolization with thrombin injection is very rare. Herein, we describe a case of a pulmonary artery pseudoaneurysm that was successfully treated by endovascular thrombin injection using a microcatheter because of the difficulty in performing a coil embolization due to a short feeding artery.

Shin, Jin Ho; Shin, Ji Hoon; Yoon, Hyun Ki [Dept. of Radiology and Research Institute of Radiology, Asan Medical Center, Ulsan University College of Medicine, Seoul (Korea, Republic of)

2011-12-15

68

Ultrasonic-Guided Percutaneous Injection of Pancreatic Pseudoaneurysm with Thrombin  

International Nuclear Information System (INIS)

Pancreatic pseudoaneurysm is a relatively uncommon complication of chronic pancreatitis, with an associated high mortality if rupture or hemorrhage occurs. We present a case of pancreatic pseudoaneurysm complicating pancreatitis which was successfully treated by direct percutaneous injection of thrombin into the aneurysmal sac. Follow-up at 8 weeks did not demonstrate recurrence. This case indicates that percutaneous thrombin injection offers effective treatment of visceral arterial pseudoaneurysms

2003-06-01

69

Further characterization of ADAMTS-13 inactivation by thrombin  

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Background: The multimeric size and platelet-tethering function of von Willebrand factor (VWF) are modulated by the plasma metalloprotease, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13). In vitro ADAMTS-13 is susceptible to proteolytic inactivation by thrombin. Objectives: In this study, we aimed to characterize the inactivation of ADAMTS-13 by thrombin and to assess its physiological significance. Methods and results: By N-terminal sequencing o...

2007-01-01

70

Anticoagulants and the Propagation Phase of Thrombin Generation  

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The view that clot time-based assays do not provide a sufficient assessment of an individual's hemostatic competence, especially in the context of anticoagulant therapy, has provoked a search for new metrics, with significant focus directed at techniques that define the propagation phase of thrombin generation. Here we use our deterministic mathematical model of tissue-factor initiated thrombin generation in combination with reconstructions using purified protein components to characterize ho...

Orfeo, Thomas; Gissel, Matthew; Butenas, Saulius; Undas, Anetta; Brummel-ziedins, Kathleen E.; Mann, Kenneth G.

2011-01-01

71

Proteolysis of Human Thrombin Generates Novel Host Defense Peptides  

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The coagulation system is characterized by the sequential and highly localized activation of a series of serine proteases, culminating in the conversion of fibrinogen into fibrin, and formation of a fibrin clot. Here we show that C-terminal peptides of thrombin, a key enzyme in the coagulation cascade, constitute a novel class of host defense peptides, released upon proteolysis of thrombin in vitro, and detected in human wounds in vivo. Under physiological conditions, these peptides exert ant...

Papareddy, Praveen; Rydenga?rd, Victoria; Pasupuleti, Mukesh; Walse, Bjo?rn; Mo?rgelin, Matthias; Chalupka, Anna; Malmsten, Martin; Schmidtchen, Artur

2010-01-01

72

Proteolysis of human thrombin generates novel host defense peptides.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The coagulation system is characterized by the sequential and highly localized activation of a series of serine proteases, culminating in the conversion of fibrinogen into fibrin, and formation of a fibrin clot. Here we show that C-terminal peptides of thrombin, a key enzyme in the coagulation cascade, constitute a novel class of host defense peptides, released upon proteolysis of thrombin in vitro, and detected in human wounds in vivo. Under physiological conditions, these peptides exert ant...

Papareddy, Praveen; Rydenga?rd, Victoria; Pasupuleti, Mukesh; Walse, Bjo?rn; Mo?rgelin, Matthias; Chalupka, Anna; Malmsten, Martin; Schmidtchen, Artur

2010-01-01

73

Platelet Factor 4 Inhibits Thrombomodulin-dependent Activation of Thrombin-activatable Fibrinolysis Inhibitor (TAFI) by Thrombin*  

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Thrombomodulin (TM) is a cofactor for thrombin-mediated activation of protein C and thrombin-activatable fibrinolysis inhibitor (TAFI) and thereby helps coordinate coagulation, anticoagulation, fibrinolysis, and inflammation. Platelet factor 4 (PF4), a platelet ?-granule protein and a soluble cofactor for TM-dependent protein C activation, stimulates protein C activation in vitro and in vivo. In contrast to stimulation of protein C activation, PF4 is shown here to inhibit activation of TAFI ...

Mosnier, Laurent O.

2011-01-01

74

Recent dielectronic recombination experiments  

International Nuclear Information System (INIS)

New recombination experiments with merged cold beams of electrons and atomic ions have been carried out at the storage ring facilities TSR in Heidelberg, ESR in Darmstadt, and CRYRING in Stockholm. A brief overview is given on the recent activities in which the Giessen group was engaged. Topics of this research were dielectronic recombination (DR) of astrophysically relevant ions, recombination of highly charged ions with respect to cooling losses in storage rings, field effects on DR, search for interference effects in photorecombination of ions, correlation effects in DR of low-Z ions, spectroscopy of high-Z ions by DR, and lifetimes of metastable states deduced from DR experiments

1998-11-01

75

A critical role for Gly25 in the B chain of human thrombin.  

Science.gov (United States)

We have recently identified (Akhavan S et al., Thromb Haemost 2000; 84: 989-97) a patient with a mild bleeding diathesis associated to an homozygous mutation in the thrombin B chain (Gly25Ser, chymotrypsinogen numbering, i.e. position 330 in human prothrombin numbering). Transient transfection of wild-type prothrombin (FII-WT) and mutant prothrombin (designated FII-G25(330)S) cDNA in COS-7 cells showed a mild reduction (50%) in FII-G25(330)S production. Recombinant proteins, stably expressed in Chinese hamster ovary cells, were isolated and activated by Taipan snake or Echis carinatus venoms. We show that the G25(330)S mutation results in a decrease in the rate of prothrombin proteolytic activation. The mutation also significantly decreases (i) the catalytic activity of thrombin with a 9-fold reduction in catalytic efficiency of the mutant toward S-2238; (ii) the interaction with benzamidine; (iii) the rate of inhibition by TLCK and antithrombin; and (iv) the rate of hydrolysis of macromolecular substrates (fibrinogen, protein C). In contrast, exosite I does not appear to be affected by the molecular defect. These results, together with molecular modeling and dynamics, indicate that Gly25(330) is important for proper expression and probably proper folding of prothrombin, and also plays a critical role in both the alignment of the catalytic triad and the flexibility of one of the activation segments of prothrombin. PMID:15634277

Akhavan, S; Miteva, M A; Villoutreix, B O; Venisse, L; Peyvandi, F; Mannucci, P M; Guillin, M C; Bezeaud, A

2005-01-01

76

Oxybutynin Topical  

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Oxybutynin topical gel is used to treat overactive bladder (a condition in which the bladder muscles contract ... the bladder even when it is not full). Oxybutynin gel is in a class of medications called ...

77

Tacrolimus Topical  

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Tacrolimus ointment is used to treat the symptoms of eczema (atopic dermatitis; a skin disease that causes ... whose eczema has not responded to another medication. Tacrolimus is in a class of medications called topical ...

78

Mometasone Topical  

Science.gov (United States)

Mometasone is used to relieve the itching and inflammation of numerous skin conditions.This medication is sometimes ... Mometasone comes as a topical cream, ointment, and lotion. It usually is applied externally once a day. ...

79

In vitro anti-inflammatory and anti-coagulant effects of antibiotics towards Platelet Activating Factor and thrombin  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Sepsis is characterized as a systemic inflammatory response that results from the inability of the immune system to limit bacterial spread during an ongoing infection. In this condition the significant mediator of inflammation Platelet Activating Factor (PAF and the coagulant factor thrombin are implicated. In animal models, treatment with PAF-antagonists or co-administration of antibiotics with recombinant-PAF-Acetylhydrolase (rPAF-AH have exhibited promising results. In order to examine the putative anti-inflammatory and/or antithrombotic interactions between antibiotic treatment used in sepsis with PAF and/or thrombin, we studied the in vitro effects of these compounds towards PAF or/and thrombin related activities and towards PAF basic metabolic enzymes. Methods We assessed the inhibitory effect of these drugs against PAF or thrombin induced aggregation on washed rabbit platelets (WRPs or rabbit Platelet Reach Plasma (rPRP by evaluating their IC50 values. We also studied their effect on Cholinephosphotransferase of PAF (PAF-CPT/Lyso-PAF-Acetyltransferase (Lyso-PAF-AT of rabbit leukocytes (RLs, as well as on rabbit plasma-PAF-AH, the key enzymes of both de novo/remodelling PAF biosynthesis and PAF degradation, respectively. Results Several antibiotics inhibited PAF-induced platelet aggregation of both WRPs and rPRP in a concentration-depended manner, with clarithromycin, azithromycin and amikacin exhibiting the higher inhibitory effect, while when combined they synergistically inhibited PAF. Higher concentrations of all antibiotics tested were needed in order to inhibit PAF induced aggregation of rPRP, but also to inhibit thrombin induced aggregation of WRPs. Concentrations of these drugs similar to their IC50 values against PAF activity in WRPs, inhibited also in vitro PAF-CPT and Lyso-PAF-AT activities of rabbit leukocytes, while only clarithromycin and azithromycin increased rabbit plasma-PAF-AH activity. Conclusions These newly found properties of antibiotics used in sepsis suggest that apart from their general actions, these drugs may present additional beneficial anti-inflammatory and anti-coagulant effects against the onset and establishment of sepsis by inhibiting the PAF/PAF-receptor and/or the thrombin/protease-activated-receptor-1 systems, and/or by reducing PAF-levels through both PAF-biosynthesis inhibition and PAF-catabolism induction. These promising in vitro results need to be further studied and confirmed by in vivo tests, in order to optimize the efficacy of antibiotic treatment in sepsis.

Demopoulos Constantinos A

2011-07-01

80

Thrombin, a mediator of cerebrovascular inflammation in AD and hypoxia  

Directory of Open Access Journals (Sweden)

Full Text Available Considerable evidence implicates hypoxia and vascular inflammation in Alzheimer’s disease (AD. Thrombin, a multifunctional inflammatory mediator, is demonstrable in the brains of AD patients both in the vessel walls and senile plaques. Hypoxia-inducible factor 1? (HIF-1?, a key regulator of the cellular response to hypoxia, is also upregulated in the vasculature of human AD brains. The objective of this study is to investigate inflammatory protein expression in the cerebrovasculature of transgenic AD mice and to explore the role of thrombin as a mediator of cerebrovascular inflammation and oxidative stress in AD and in hypoxia-induced changes in brain endothelial cells. Immunofluorescent analysis of the cerebrovasculature in AD mice demonstrates significant (p<0.01-0.001 increases in thrombin, HIF-1?, interleukin-6 (IL-6, monocyte chemoattractant protein-1 (MCP-1, matrix metalloproteinases (MMPs, and reactive oxygen species (ROS compared to controls. Administration of the thrombin inhibitor dabigatran (100 mg/kg to AD mice for 34 wks significantly decreases expression of inflammatory proteins and ROS. Exposure of cultured brain endothelial cells to hypoxia for 6 h causes an upregulation of thrombin, HIF-1?, MCP-1, IL-6 and MMP2 and ROS. Treatment of endothelial cells with the dabigatran (1 nM reduces ROS generation and inflammatory protein expression (p<0.01-0.001. The data demonstrate that inhibition of thrombin in culture blocks the increase in inflammatory protein expression and ROS generation evoked by hypoxia. Also, administration of dabigatran to transgenic AD mice diminishes expression of inflammatory proteins and ROS in the cerebromicrovasculature. Taken together, these results suggest that inhibiting thrombin generation could have therapeutic value in AD and other disorders where hypoxia, inflammation and oxidative stress are involved.

PaulaGrammas

2013-05-01

 
 
 
 
81

Influence of coagulation factors and tissue factor concentration on the thrombin generation test in plasma.  

Science.gov (United States)

The thrombin generation test is used to study coagulation in patients with haemorrhagic diseases or with high thrombotic risk. To our knowledge, this is the first study investigating the relative influence of coagulation factors on thrombin generation in plasma. The aim was to investigate the influence of coagulant factors, anticoagulant factors, and tissue factor (TF) on three parameters: endogenous thrombin potential (ETP), peak thrombin concentration, and lag time for the appearance of thrombin. At a low TF concentration, all factors except factor XI influenced thrombin generation. At a high TF concentration, only the factors of the extrinsic pathway exerted an influence. ETP and peak thrombin were linearly correlated to factor II concentration. Factor V and factor VII effects increased hyperbolically with factor concentration. The influence of factor X on thrombin generation depended on TF concentration. In the absence of factor VIII and factor IX, ETP fell to 60-70% of the normal when peak thrombin fell to 25-30% of the normal. Fibrinogen concentration influenced ETP and peak thrombin and decreasing fibrinogen levels shortened the lag time. As expected, decreasing antithrombin concentration caused dramatic increases in thrombin generation. Protein S prolonged the lag time, especially at a low TF concentration. No effect of protein C was observed, likely due to the absence of thrombomodulin. The thrombin generation test was more sensitive to factor deficiencies at low than at high TF concentration. ETP was not the most critical parameter for studying coagulation factor deficiencies. Instead, peak thrombin was the most sensitive parameter. PMID:18392335

Duchemin, Jérôme; Pan-Petesch, Brigitte; Arnaud, Bertrand; Blouch, Marie-Thérèse; Abgrall, Jean-François

2008-04-01

82

Models for thrombin generation and risk of disease.  

Science.gov (United States)

Computational models can offer an integrated view of blood clotting dynamics and may ultimately be instructive regarding an individual's risk of bleeding or clotting. Appropriately, developed and validated models could allow clinicians to simulate the outcomes of therapeutics and estimate risk of disease. Computational models that describe the dynamics of thrombin generation have been developed and have been used in combination with empirical studies to understand thrombin dynamics on a mechanistic basis. The translation of an individual's specific coagulation factor composition data using these models into an integrated assessment of hemostatic status may provide a route for advancing the long-term goal of individualized medicine. This review details the integrated approaches to understanding: (i) What is normal thrombin generation in individuals? (ii) What is the effect of normal range plasma composition variation on thrombin generation in pathologic states? (iii) Can disease progression or anticoagulation be followed by understanding the boundaries of normal thrombin generation defined by plasma composition? (iv) What are the controversies and limitations of current computational approaches? Progress in these areas can bring us closer to developing models that can be used to aid in identifying hemostatic risk. PMID:23809125

Brummel-Ziedins, K

2013-06-01

83

Management of surgical hemostasis: topical agents.  

Science.gov (United States)

Intraoperative control of bleeding during any surgical procedure is vital for achieving a positive patient outcome. Hemostasis can be achieved through practical and effective systemic or topical approaches. A variety of hemostatic methods can be employed, ranging from simple manual pressure application with one finger to electrical tissue cauterization, systemic administration of blood products, and systemic administration or topical application of procoagulation agents. The key to surgical success is critically dependent on knowledgeable use of a method appropriate for the level of bleeding experienced by the patient. Topical agents can be effective as adjuncts to aid in hemostasis when bleeding is not controllable with pressure application, vessel ligation, or electrocautery. Such adjunctive hemostatic treatments include topical gelatins, collagens, oxidized celluloses, thrombin and fibrin sealants, synthetic glues, and glutaraldehyde-based glues. As with the use of systemically delivered hemostatic agents, topical treatments also carry risks with their use, and their efficacy has not been extensively studied in large randomized, placebo-controlled prospective studies. The effective use of topical agents is highly dependent on the surgeon's experience or preference and their availability in the surgical setting. In this article, we review the currently available topical hemostatic agents, compare their efficacy, and give general recommendations for their use in the operating room. PMID:18544302

Sileshi, Bantayehu; Achneck, Hardean E; Lawson, Jeffrey H

2008-01-01

84

Participation of the hypophyseal-adrenal cortex system in thrombin clearance during immobilization stress  

Science.gov (United States)

Thrombin marked with I-131 resulted in a considerable increase of the thrombined clearance rate in healthy male rats during stress caused by an immobilization lasting 30 minutes, and in an increase of thrombin clearance occurred by a combination of immobilization and administration of adrenocorticotropin (ACTH). Contrary to ACTH, the thrombin clearance is not stimulated in healthy animals by hydrocortisone. The results of the examination are presented.

Kudryashov, B. A.; Uljanov, A. M.; Shapiro, F. B.; Bazazyan, G. G.

1981-01-01

85

[Thrombin--a regulator of reparative processes in wound healing].  

Science.gov (United States)

Thrombin, binding to receptors of the protease activated receptor (PAR) family, is involved in wound healing by inducing the reparation processes and regulating the activity of mast cells, which secrete mediators of inflammation. Using thrombin receptor agonist peptide (TRAP-6) for the activation of rat mast cells, effect of several receptors, including PAR-1, on mast cells was demonstrated. It was shown that TRAP increases the concentration of Ca2+ in the cytoplasm of mast cells and regulates cell degranulation, while releasing nitrogen oxide. Thrombin encapsulated in poly(N-vinyl caprolactam)-calcium alginate (PVCL-Ca-Alg) hydrogel films promotes wound healing in rats as demonstrated by the acceleration of fibroblast proliferation and neovascularization. PMID:9612571

Strukova, S M; Dugina, T N; Chistov, I V; Markvicheva, E A; Kuptsova, S V; Kolokol'chikova, E G; Rumsh, L D; Zubov, V P; Gluza, E

1998-04-01

86

Fractal gold modified electrode for ultrasensitive thrombin detection  

Science.gov (United States)

We report a label-free and ultrasensitive aptasensor based on a fractal gold modified (FracAu) electrode for thrombin detection with a femtomolar detection limit. The FracAu electrode was prepared by electrodeposition of hydrogen tetrachloroaurate (HAuCl4) onto a bare indium tin oxide (ITO) electrode surface. After this process the electrode was characterized by SEM. A thiol-modified aptamer against thrombin was immobilized on the FracAu electrode through a self-assembling process. Upon thrombin binding, the interfacial electron transfer of the FracAu electrode was perturbed by the formation of an aptamer-thrombin complex. The concentration of thrombin in the sample solution was determined by measuring the change in the oxidation peak current of hydroxymethyl ferrocene (C11H12FeO) with differential pulse voltammetry (DPV). The current response (reduced peak current) had a linear relationship with the logarithm of thrombin concentrations in the range of 10-15 to 10-10 M with a detection limit of 5.7 fM. Furthermore, the as-prepared FracAu electrode exhibited high selectivity. The application of FracAu electrodes may be extended to prepare other types of biosensors, such as immunosensors, enzyme biosensors and DNA biosensors. These results show that FracAu electrodes have great promise for clinical diagnosis of disease-related biomarkers.We report a label-free and ultrasensitive aptasensor based on a fractal gold modified (FracAu) electrode for thrombin detection with a femtomolar detection limit. The FracAu electrode was prepared by electrodeposition of hydrogen tetrachloroaurate (HAuCl4) onto a bare indium tin oxide (ITO) electrode surface. After this process the electrode was characterized by SEM. A thiol-modified aptamer against thrombin was immobilized on the FracAu electrode through a self-assembling process. Upon thrombin binding, the interfacial electron transfer of the FracAu electrode was perturbed by the formation of an aptamer-thrombin complex. The concentration of thrombin in the sample solution was determined by measuring the change in the oxidation peak current of hydroxymethyl ferrocene (C11H12FeO) with differential pulse voltammetry (DPV). The current response (reduced peak current) had a linear relationship with the logarithm of thrombin concentrations in the range of 10-15 to 10-10 M with a detection limit of 5.7 fM. Furthermore, the as-prepared FracAu electrode exhibited high selectivity. The application of FracAu electrodes may be extended to prepare other types of biosensors, such as immunosensors, enzyme biosensors and DNA biosensors. These results show that FracAu electrodes have great promise for clinical diagnosis of disease-related biomarkers. Electronic supplementary information (ESI) available: Fig. S1 showing current reductions of FracAu and bulk Au biosensors, Fig. S2 showing cyclic voltammogram of FracAu and bulk Au electrode in 0.5 M H2SO4 aqueous solution. See DOI: 10.1039/c2nr30826f

Xu, Li-Ping; Wang, Shuqi; Dong, Haifeng; Liu, Guodong; Wen, Yongqiang; Wang, Shutao; Zhang, Xueji

2012-05-01

87

Cellular signaling events involved in thrombin activation of vascular endothelium  

International Nuclear Information System (INIS)

Although cytosolic calcium ([Ca])/sub I/), inositol trisphosphate (IP_3) and diacylglycerol (DAG) are important second messengers involved in stimulus-response coupling to certain hormones, little information is available regarding their role in the activation of vascular endothelial cells (EC) during coagulation. The authors have used cultured human umbilical vein EC to examine thrombin effects on [Ca]/sub I/ and on IP_3 and DAG formation. Thrombin (1 U/ml) induces a rapid (peak < 15 sec) increase in [Ca]/sub I/ (300% basal levels) in suspensions of fura-2 (fluorescent Ca"2"+ indicator)-loaded EC. In addition thrombin stimulates concentration-dependent (.001-1 U/ml) increases in calcium efflux and IP_3 formation in EC prelabeled with "4"5Ca or "3H-myoinositol. Peak IP_3 (182+/-14% control) is rapid (<15 sec) and temporally similar to the rise in [Ca]/sub I/. In "3H-arachidonic acid-labeled EC, thrombin increases DAG (protein kinase C activator) at 15 sec (133+/-8% control), as well as 5 min (148+/-12% control). EC preincubation with 4?-phorbol 12-myristate 13-acetate (10"-"7M, 5 min), a potent activator of protein kinase C, blocks thrombin (1 U/ml)-induced increases in [Ca]/sub I/ and IP_3. Thus, thrombin may trigger at least two distinct signaling pathways (IP_3/calcium; DAG/protein kinase C) in EC. In addition, DAG stimulation of protein kinase C may influence this mediator's action in vascular EC

1986-03-05

88

Horn fly (Diptera: Muscidae) saliva targets thrombin action in hemostasis.  

Science.gov (United States)

The horn fly, Hematobia irritans (L.), is an important pest of livestock because the adult stage of both sexes are aggressive blood-feeders. Remarkably, even though horn fly adults feed recurrently on their hosts as ectoparasites, these flies lack the ADP-responsive antiplatelet aggregation and vasodilatory antihemostatic systems described for other blood-feeding Diptera. Horn fly salivary gland extracts do interfere with the normal coagulation process as demonstrated by the recalcification time assay. Using this as a baseline, the effects of saliva on recalcification time, activated partial thromboplastin time, prothrombin time, and thrombin time were measured to determine which arm(s) of the coagulation cascade might be impacted. Factor-deficient plasma assays also were used to measure possible perturbations in clotting. Gland-free saliva delayed the recalcification time as well as the activated partial thromboplastin time, prothrombin time, and thrombin time. Saliva also further delayed clotting times of plasmas deficient in factor V, factor VIII, and factor XIII, indicating that other factors in the coagulation cascade were inhibited. Although horn fly saliva did not alter the ability of deficient plasma reconstituted with factor X to clot, it did inhibit deficient plasma reconstituted with factor II (thrombin). Antithrombin activity in saliva was confirmed by its ability to interfere with thrombin hydrolysis of fibrinogen, its normal substrate, and by its inhibition of thrombin action on a chromagenic substrate that mimics the hydrolytic site of fibrinogen. Thus, horn fly saliva contains a factor that specifically targets thrombin, a key component in the coagulation cascade. While the biochemical mechanisms of inhibition may vary, this antihemostatic characteristic is shared with other zoophilic Diptera such as black flies, Simulium spp., and tsetse, Glossina morsitans morsitans Westwood, that feed on ungulates. PMID:15535586

Cupp, M S; Zhang, D; Cupp, E W

2000-05-01

89

Basis for the reduced affinity of beta T- and gamma T-thrombin for hirudin.  

Science.gov (United States)

Partial proteolysis of human alpha-thrombin by trypsin results in the formation of beta T-thrombin and gamma T-thrombin which have a reduced affinity for the inhibitor hirudin and the cell-surface cofactor thrombomodulin as well as reduced activity with fibrinogen. The basis of the reduction in affinity of these thrombin derivatives for hirudin has been investigated by examining their kinetics of interaction with a number of hirudin mutants differing in their C-terminal charge properties as well as with a truncated form of hirudin. The results indicate that the reduced affinity of beta T-thrombin for hirudin is most likely due to a decrease in the strength of nonionic interactions between thrombin and the C-terminal region of hirudin. No decrease in the strength of ionic interactions was observed with beta T-thrombin. In contrast, the reduced affinity of gamma T-thrombin was due to a decrease in the strength of both ionic and nonionic interactions. The N-terminal core region of hirudin, which interacts predominantly with the active-site cleft of thrombin, exhibited similar affinities for alpha-, beta T-, and gamma T-thrombin, indicating that thrombin-hirudin interactions within the active site are largely preserved in beta T- and gamma T-thrombin. PMID:2018764

Stone, S R; Hofsteenge, J

1991-04-23

90

[Effect of thrombin stimulated blood platelets on plasma fibrinolytic activity].  

Science.gov (United States)

The influence of thrombin stimulated-blood platelets on plasma fibrinolytic activity was evaluated. Thrombin-activated blood platelets have been shown to significantly inhibit plasma fibrinolytic activity before and after venous stasis. This was expressed by a reduction of the digestion area of fibrin dish from 10.3 +/- 3.3 cm2 to 3.7 +/- 1.5 cm2 and from 15.6 +/- 6.8 cm2 to 3.7 +/- 1.7 cm2, respectively. PMID:1293908

Komarnicki, M; Ka?mierczak, M; Krupa, D

1992-01-01

91

PKC? mediates thrombin augmented fibroblast-mediated collagen gel contraction  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fibroblast-mediated collagen gel contraction has been used as an in vitro model of tissue remodeling. Thrombin is one of the mediators present in the milieu of airway inflammation and may be involved in airway tissue remodeling. We have previously reported that thrombin stimulates fibroblast-mediated collagen gel contraction partially through the PAR1/PKC? signaling pathway (Fang et al, ERJ, 2004; 24: 918-924). Here we further report that the delta-isoform of PKC (PKC?) is also activated by...

Fang, Qiuhong; Mao, Lijun; Kobayashi, Tetsu; Wang, Xingqi; Wyatt, Todd A.; Kim, Huijung; Liu, Xiangde; Rennard, Stephen I.

2008-01-01

92

Heparin-like tubings. III. Kinetics and mechanism of thrombin, antithrombin III and thrombin-antithrombin complex adsorption under controlled-flow conditions.  

Science.gov (United States)

In previous papers, we described treated tubular materials which exhibit an heparin-like antithrombic activity under dynamic conditions. In order to ascertain the heparin-like mechanism of this activity, we have studied the interactions of thrombin, antithrombin III and thrombin-antithrombin III complex with the inner face of these treated tubings under controlled-flow conditions. Moreover, the kinetics of the adsorption of thrombin were studied at different flow rates to establish the rate-determining step. PMID:3224126

Migonney, V; Fougnot, C; Jozefowicz, M

1988-09-01

93

Thrombin induces surface and intracellular secretion of amyloid precursor protein from human endothelial cells.  

Science.gov (United States)

Thrombin, a major coagulant and inflammatory mediator, was shown to regulate amyloid precursor protein (APP) secretion. APP is the protein from which the amyloid beta peptide (A(beta)) is derived. A(beta) forms the core of vascular and cerebral plaques in Alzheimer's disease (AD). In this study, human umbilical vein endothelial cells (HUVEC) were used to examine the effects of thrombin on APP expression. Cell supernatants from thrombin-treated HUVEC were immunoblotted to measure secreted APP. Thrombin-induced secretion of APP peaks at approximately 30 min post-treatment. Immunohistochemical analysis found that APP is not colocalized with or secreted through the same pathway as coagulation factor VIII. The secretion of APP is thrombin receptor-mediated, since it is inhibited by the thrombin antagonist N-Acetyl-D-Phe-Pro-1-Amido-4-Guanidino-Butyl-1-Boronic Acid. It also is induced by treatment with a calcium ionophore. Moreover, APP secretion is protein kinase C (PKC)-dependent because it is blocked by the PKC inhibitor bisindolylmaleimide. APP secretion also occurs from the cell surface, possibly through direct cleavage by thrombin. Immunoreactivity on the surface of HUVEC decreased after thrombin treatment but not after treatment with a non-proteolytic thrombin receptor activator. These data suggest that thrombin induces APP secretion through a PKC-dependent mechanism, as well as from the cell surface. Our results are consistent with thrombin playing a role in AD pathology. PMID:10235452

Ciallella, J R; Figueiredo, H; Smith-Swintosky, V; McGillis, J P

1999-04-01

94

Immobilized thrombin receptor agonist peptide accelerates wound healing in mice.  

Science.gov (United States)

To accelerate the healing processes in wound repair, attempts have been repeatedly made to use growth factors including thrombin and its peptide fragments. Unfortunately, the employment of thrombin is limited because of its high liability and pro-inflammatory actions at high concentrations. Some cellular effects of thrombin in wound healing are mediated by the activation of protease activated receptor-1 (PAR-1). The thrombin receptor agonist peptide (TRAP:SFLLRN) activates this receptor and mimics the effects of thrombin, but TRAP is a relatively weak agonist. We speculated that the encapsulated peptide may be more effective for PAR-1 activation than nonimmobilized peptide and developed a novel method for TRAP encapsulation in hydrogel films based on natural and synthetic polymers. The effects of an encapsulated TRAP in composite poly(N-vinyl caprolactam)-calcium alginate (PVCL) hydrogel films were investigated in a mouse model of wound healing. On day 7 the wound sizes decreased by about 60% under TRAP-chitosan-containing PVCL films, as compared with control films without TRAP. In the case of TRAP-polylysine-containing films no significant decrease in wound sizes was found. The fibroblast/macrophage ratio increased under TRAP-containing films on day 3 and on day 7. The number of proliferating fibroblasts increased to 150% under TRAP-chitosan films on day 7 as compared with control films. The number of [3H]-thymidine labeled endothelial and epithelial cells in granulation tissues was also enhanced. Thus, the immobilized TRAP to PVCL-chitosan hydrogel films were found to promote wound healing following the stimulation of fibroblast and epithelial cell proliferation and neovascularization. Furthermore, TRAP was shown to inhibit the secretion of the inflammatory mediator PAF from stimulated rat peritoneal mast cells due to augmentation of NO release from the mast cells. The encapsulated TRAP is suggested to accelerate wound healing due to the anti-inflammatory effects and earlier development of the proliferative phase of wound healing. PMID:11697718

Strukova, S M; Dugina, T N; Chistov, I V; Lange, M; Markvicheva, E A; Kuptsova, S; Zubov, V P; Glusa, E

2001-10-01

95

Homologous desensitization of HEL cell thrombin receptors. Distinguishable roles for proteolysis and phosphorylation.  

Science.gov (United States)

Loss of sensitivity to thrombin following an initial response is characteristic of a number of cell types, including platelets. It has recently been proposed that thrombin receptors resemble other G protein-coupled receptors, but that activation involves a novel mechanism in which thrombin cleaves the receptor, exposing a new N terminus that serves as the ligand for the receptor. Based upon this model, we have examined the mechanism of thrombin receptor desensitization by comparing the effects of thrombin with those of a peptide corresponding to the N-terminal sequence of the receptor following proteolysis by thrombin: SFLLRNPNDKYEPF or TRP42/55. Like thrombin, TRP42/55 stimulated pertussis toxin-sensitive inositol 1,4,5-trisphosphate formation, raised cytosolic Ca2+, and inhibited cAMP formation in the megakaryoblastic HEL cell line. Exposure to either thrombin or TRP42/55 desensitized the cells to both, but not to a third agonist, neuropeptide Y. The rate of recovery after desensitization depended upon the order of agonist addition. Resensitization of the cell to thrombin following a brief exposure to thrombin required up to 24 h and could be inhibited with cycloheximide. Resensitization to TRP42/55 after exposure to thrombin, or to thrombin after exposure to TRP42/55, on the other hand, was detectable within 30 min and could be inhibited by serine/threonine phosphatase inhibitors, but not by cycloheximide. Loss of responsiveness to thrombin and TRP42/55 was also observed following addition of the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). However, while the protein kinase inhibitor staurosporine completely prevented the desensitization caused by TPA, it had only a limited effect on the desensitization caused by TRP42/55. These results demonstrate that the G protein-mediated effects of thrombin can be reproduced by a receptor-derived peptide and suggest that desensitization occurs by at least two mechanisms. The first, which is seen with thrombin, but not TRP42/55, involves proteolysis and requires protein synthesis for recovery. The second, which occurs with TRP42/55 and TPA, as well as with thrombin, involves phosphorylation, possibly of the receptor itself. Although protien kinase C is activated by thrombin and is presumably responsible for the desensitization caused by TPA, it does not appear to play a major role in receptor desensitization caused by thrombin and TRP42/55. This suggests that other kinases, such as those which inactivate adrenergic receptors and rhodopsin, are involved in the down-regulation of thrombin receptor function. PMID:1313426

Brass, L F

1992-03-25

96

Thrombin generation using the calibrated automated thrombinoscope to assess reversibility of dabigatran and rivaroxaban.  

Science.gov (United States)

The new direct-acting anticoagulants such as dabigatran and rivaroxaban are usually not monitored but may be associated with haemorrhage, particularly where renal impairment occurs. They have no effective "antidotes". We studied 17 patients receiving dabigatran 150 mg twice daily for non-valvular atrial fibrillation and 15 patients receiving rivaroxaban 10 mg daily for the prevention of deep venous thrombosis after hip or knee replacement surgery. We assessed the effect of these drugs on commonly used laboratory tests and Calibrated Automated Thrombogram (CAT) using plasma samples. We also assessed effects in fresh whole blood citrated patient samples using thromboelastography on the TEG and the ROTEM. The efficacy of nonspecific haemostatic agents prothrombin complex concentrate (PCC), Factor VIII Inhibitor By-passing Activity (FEIBA) and recombinant activated factor VII (rVIIa) were tested by reversal of abnormal thrombin generation using the CAT. Concentrations added ex vivo were chosen to reflect doses normally given in vivo. Dabigatran significantly increased the dynamic parameters of the TEG and ROTEM and the lag time of the CAT. It significantly reduced the endogenous thrombin potential (ETP) and reduced the peak height of the CAT. Rivaroxaban did not affect the TEG and ROTEM parameters but did increase the lag time and reduce ETP and peak height of the CAT. For both drugs, these parameters were significantly and meaningfully corrected by PCC and FEIBA and to a lesser but still significant extent by rFVIIa. These results may be useful in devising a reversal strategy in patients but clinical experience will be needed to verify them. PMID:24352511

Herrmann, R; Thom, J; Wood, A; Phillips, M; Muhammad, S; Baker, R

2014-05-01

97

The NMR solution structure of recombinant RGD-hirudin  

International Nuclear Information System (INIS)

The solution structure of a new recombinant RGD-hirudin, which has the activities of anti-thrombin and anti-platelet aggregation, was determined by 1H nuclear magnetic resonance spectroscopy and compared with the conformations of recombinant wild-type hirudin and hirudin (variant 2, Lys47) of the hirudin thrombin complex. On the basis of total 1284 distance and dihedral angle constraints derived from a series of NMR spectra, 20 conformers were computed with ARIA/CNS programs. The structure of residues 3-30 and 37-48 form a molecular core with two antiparallel ?-sheets as the other two hirudins. However, significant differences were found in the surface electrostatic charge distributions among the three hirudins, especially in the RGD segment of recombinant RGD-hirudin. This difference may be greatly beneficial to its additional function of anti-platelet aggregation. The difference in extended C-terminal makes its both ionic and hydrophobic interactions with the fibrinogen recognition exosite of thrombin more effective

2007-08-17

98

Design of an in vivo cleavable disulfide linker in recombinant fusion proteins  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In order to achieve an optimal biological activity and desired pharmacokinetic profiles, a dithiocyclopeptide linker was designed for in vivo release of protein domains from a recombinant fusion protein. This novel in vivo cleavable disulfide linker, based on a dithiocyclopeptide containing a thrombin-sensitive sequence and an intra-molecular disulfide bond, was inserted between transferrin and granulocyte colony-stimulating factor recombinant fusion protein domains. After expression of the f...

Chen, Xiaoying; Bai, Yun; Zaro, Jennica L.; Shen, Wei-chiang

2010-01-01

99

Nonradiative recombination in semiconductors  

CERN Document Server

In recent years, great progress has been made in the understandingof recombination processes controlling the number of excessfree carriers in semiconductors under nonequilibrium conditions. As a result, it is now possible to give a comprehensivetheoretical description of these processes. The authors haveselected a number of experimental results which elucidate theunderlying physical problems and enable a test of theoreticalmodels. The following topics are dealt with: phenomenological theory ofrecombination, theoretical models of shallow and deep localizedstates, cascade model of carrier captu

Abakumov, VN; Yassievich, IN

1991-01-01

100

Thrombin-Binding Aptamer Quadruplex Formation: AFM and Voltammetric Characterization  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The adsorption and the redox behaviour of thrombin-binding aptamer (TBA) and extended TBA (eTBA) were studied using atomic force microscopy and voltammetry at highly oriented pyrolytic graphite and glassy carbon. The different adsorption patterns and degree of surface coverage were correlated with the sequence base composition, presence/absence of K+, and voltammetric behaviour of TBA and eTBA. In the presence of K+, only a few single-stranded sequences present adsorption, while the majority ...

Diculescu, Victor Constantin; Chiorcea-paquim, Ana-maria; Eritja, Ramon; Oliveira-brett, Ana Maria

2010-01-01

 
 
 
 
101

Thrombin and plasmin activity in coronary artery disease.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Basal plasmin and thrombin activity in plasma were assessed by radioimmunoassay of the fibrinogen derivatives containing the sequence B beta 15-42 and of fibrinopeptide A respectively in a cross sectional controlled study of men with coronary artery disease. Compared with healthy controls (n = 33) men with angiographically defined coronary artery disease (n = 98) had a modest but significant increase in concentrations of fibrinopeptide A, indicating an activated coagulation system. Concentrat...

Small, M.; Lowe, G. D.; Douglas, J. T.; Hutton, I.; Lorimer, A. R.; Forbes, C. D.

1988-01-01

102

Argatroban-coupled Affi-Gel matrix for the purification of thrombin from plasma.  

Science.gov (United States)

Sometimes it is necessary to obtain thrombin from limited amounts of human plasma for laboratory assay. None of the available purification methods easily deals with this subject. The procedure described in the present paper uses a readily available pharmaceutical agent, argatroban, to construct an affinity matrix. Argatroban has a high affinity for thrombin and its thrombin binding is reversible. Prothrombin derived from a Ba(2+) precipitate of human plasma is used as the starting material. The crude prothrombin can be bulk activated to thrombin using taipan-snake (Oxyuranus scutellatus) venom and bound to the argatroban-coupled matrix without further processing steps. The thrombin product eluted from the argatroban matrix is very pure as judged by high specific activity and by electrophoresis. This purification scheme is rapid, yielding purified thrombin within 2 days. PMID:15801910

Lefkowitz, Jerry B

2005-10-01

103

Thrombin-induced cerebral hemorrhage: role of protease-activated receptor-1.  

Science.gov (United States)

Thrombin causes blood-brain barrier disruption, and this study examined whether thrombin can cause brain hemorrhage through protease-activated receptor-1 (PAR-1). Male wild type and PAR-1 knockout mice had an intracerebral injection of thrombin or saline. Mice then underwent serial T2 magnetic resonance imaging and were euthanized for brain hemoglobin, iron, and interleukin-1? measurements. Thrombin caused massive T2 lesions and brain hemorrhage in wild type mice. These effects were markedly reduced in PAR-1 knockout mice. Thrombin also increased brain interleukin-1?, and this was absent in PAR-1 knockout mice. In conclusion, thrombin increases interleukin-1? levels and induces intracerebral hemorrhage through PAR-1 activation. PMID:24323711

Cheng, Yingying; Xi, Guohua; Jin, Hang; Keep, Richard F; Feng, Jiachun; Hua, Ya

2014-08-01

104

Mutant N143P Reveals How Na+ Activates Thrombin*  

Science.gov (United States)

The molecular mechanism of thrombin activation by Na+ remains elusive. Its kinetic formulation requires extension of the classical Botts-Morales theory for the action of a modifier on an enzyme to correctly account for the contribution of the E*, E, and E:Na+ forms. The extended scheme establishes that analysis of kcat unequivocally identifies allosteric transduction of Na+ binding into enhanced catalytic activity. The thrombin mutant N143P features no Na+-dependent enhancement of kcat yet binds Na+ with an affinity comparable to that of wild type. Crystal structures of the mutant in the presence and absence of Na+ confirm that Pro143 abrogates the important H-bond between the backbone N atom of residue 143 and the carbonyl O atom of Glu192, which in turn controls the orientation of the Glu192-Gly193 peptide bond and the correct architecture of the oxyanion hole. We conclude that Na+ activates thrombin by securing the correct orientation of the Glu192-Gly193 peptide bond, which is likely flipped in the absence of cation. Absolute conservation of the 143–192 H-bond in trypsin-like proteases and the importance of the oxyanion hole in protease function suggest that this mechanism of Na+ activation is present in all Na+-activated trypsin-like proteases.

Niu, Weiling; Chen, Zhiwei; Bush-Pelc, Leslie A.; Bah, Alaji; Gandhi, Prafull S.; Di Cera, Enrico

2009-01-01

105

Conformationally restricted analogs of the direct thrombin inhibitor FM 19.  

Science.gov (United States)

The serine protease thrombin plays several key roles in the clotting cascade within the hemostatic system, such as in fibrin formation and platelet activation. Thus, development of an inhibitor that binds to the enzyme's active site (a direct thrombin inhibitor) offers an approach for the treatment of thrombus-associated diseases. Previous structure-activity relationship studies originally based on the bradykinin breakdown product Arg-Pro-Pro-Gly-Phe (RPPGF) led to the development of lead compound FM 19 (d-Arg-Oic-Pro-d-Ala-Phe(p-Me)-NH(2)). The recently determined X-ray structure of FM 19 in the active site of thrombin has revealed sites of modification to potentially improve inhibition. In this study, we report the synthesis and biological characterization of nine peptides that replace only the d-Arg residue of the FM 19 sequence, investigating ways to add conformational restriction, modification of the basic moiety at the end of the side chain, and removal of the charge from the N-terminus. Two of these peptides, 6 and 7 (IC(50) values of 0.51 and 0.45 ?M, respectively), show similar potency to the best compounds in the FM 19 series reported thus far. PMID:22055408

Girnys, Elizabeth A; Porter, Vanessa R; Mosberg, Henry I

2011-12-15

106

Thrombin generation by activated factor VII on platelet activated by different agonists. Extending the cell-based model of hemostasis  

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Full Text Available Abstract Background Platelet activation is crucial in normal hemostasis. Using a clotting system free of external tissue factor, we investigated whether activated Factor VII in combination with platelet agonists increased thrombin generation (TG in vitro. Methods and results TG was quantified by time parameters: lag time (LT and time to peak (TTP, and by amount of TG: peak of TG (PTG and area under thrombin formation curve after 35 minutes (AUC?35min in plasma from 29 healthy volunteers using the calibrated automated thrombography (CAT technique. TG parameters were measured at basal conditions and after platelet stimulation by sodium arachidonate (AA, ADP, and collagen (Col. In addition, the effects of recombinant activated FVII (rFVIIa alone or combined with the other platelet agonists on TG parameters were investigated. We found that LT and TTP were significantly decreased (p 35min were significantly increased (p 35min (but not PTG when compared to platelet rich plasma activated with agonists in the absence of rFVIIa. Conclusion Platelets activated by AA, ADP, Col or rFVIIa triggered TG. This effect was increased by combining rFVIIa with other agonists. Our intrinsic coagulation system produced a burst in TG independent of external tissue factor activity an apparent hemostatic effect with little thrombotic capacity. Thus we suggest a modification in the cell-based model of hemostasis.

Herrera Maria

2006-04-01

107

Thrombin Ca(2+)-dependently stimulates protein tyrosine phosphorylation in BC3H1 muscle cells.  

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The proteinase thrombin, known to act via heptahelical G-protein-coupled receptors, is a mitogenic agent for different cell types, including the mouse muscle cell line BC3H1. In this study, the effect of thrombin on tyrosine phosphorylation was examined using anti-phosphotyrosine antibodies. Thrombin was found to induce phosphorylation of 65-70 and 110-120 kDa proteins in BC3H1 cells. The effect of thrombin was concentration-dependent, being half-maximal and maximal at concentrations of 0.03 and 1 unit/ml respectively. The thrombin-induced increase in phosphorylation was rapid (< or = 10 s) and transient, with a peak response after about 1-2 min. The effect of thrombin could be mimicked by the thrombin receptor agonist peptide SFLLRN-NH2. Preincubation of cells with pertussis toxin (PT) had no effect on thrombin-induced tyrosine phosphorylation. Epidermal growth factor, platelet-derived growth factor and insulin stimulated tyrosine phosphorylation of different proteins, among which were 65-70 and 110-120 kDa proteins. The phorbol ester 12-myristate 13-acetate (PMA) as well as the Ca2+ ionophore A23187 both stimulated tyrosine phosphorylation of proteins identical to those phosphorylated by thrombin, suggesting that activation of protein kinase C (PKC) and elevation of the cytosolic Ca2+ concentration alone are sufficient to induce tyrosine phosphorylation. However, calphostin C and other PKC inhibitors, which completely inhibited tyrosine phosphorylation induced by PMA, had no influence on the effect of thrombin, whereas loading of cells with the intracellular Ca2+ chelator bis-(O-aminophenoxy)ethane-NNN'N'-tetra-acetic acid totally blocked thrombin-stimulated tyrosine phosphorylation. Thus tyrosine phosphorylation stimulated by thrombin is an early PT-insensitive cellular response which is either directly mediated by elevation of cytosolic Ca2+ concentration or by a presently unknown mechanism that requires an elevated cytosolic Ca2+ concentration. PMID:7679896

Offermanns, S; Bombien, E; Schultz, G

1993-02-15

108

Percutaneous Ultrasound-Guided Thrombin Injection in Iatrogenic Arterial Pseudoaneurysms: Effectiveness and Complications  

International Nuclear Information System (INIS)

To evaluate and describe the efficacy and side effects of a percutaneous thrombin injection under ultrasonography guidance for the treatment of iatrogenic pseudo aneurysms Eighteen consecutive iatrogenic pseudo aneurysm cases were treated with a thrombin injection. The thrombin was injected into the pseudo aneurysm cavity using a 22-gauge needle under ultrasonographic guidance. The causes of the pseudo aneurysms are as follows: post coronary angiography (9 cases), percutaneous coronary balloon angioplasty (5 cases), cerebral angiography (1 case), transhepatic chemo embolization (1 case), percutaneous trans femoral arterial stent insertion (1 case) and bone marrow aspiration for a marrow transplant (1 case). Only one case required a secondary thrombin injection due to recurrent flow in the pseudo aneurysm lumen, which was detected at the follow up Doppler ultrasound. Other seventeen cases were successfully treated on the first trial. There were no technical failures or complication related to the procedure. The average amount of thrombin injected was 733 IU. Nine out of 18 treated patients (50%) showed mild reactions to the thrombin including mild fever (4 cases), chilling sensation (3 cases), a chilling sensation with mild dyspnea (1 case), mild chest discomfort (1 case) after the thrombin injection. All these side effects were transient and improved several hours later. All the iatrogenic pseudo aneurysms were treated successfully with an ultrasound-guided percutaneous thrombin injection. There was a high rate of hypersensitivity to the bovine thrombin, which precaution should be taken to prevent more serious side effects

2005-09-01

109

Evidence for common structural changes in thrombin induced by active-site or exosite binding.  

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The gamma-loop of thrombin is a flexible, surface-accessible loop in free thrombin that appears to be one of several sites participating in the interaction of the enzyme with macromolecular substrates and inhibitors. Using limited proteolysis and intrinsic fluorescence measurements, we have studied changes in thrombin structure induced by small, site-specific ligands. Binding of a C-terminal peptide of hirudin to the anion-binding exosite of thrombin induced a structural change in the gamma-loop, which caused a 6-fold reduction in the susceptibility of the enzyme to limited proteolysis by elastase and chymotrypsin. Binding of several active site-specific thrombin inhibitors conferred an even greater protection from proteolysis at the gamma-loop. For example, the covalent complex of thrombin with D-Phe-Pro-Arg-CH2Cl was 95-fold less susceptible to cleavage by chymotrypsin than the free enzyme. Furthermore, binding of either exosite or active-site probes induced a common intrinsic fluorescence change in thrombin (a fractional increase of 0.13). These results are surprising because crystallographic studies indicate that direct contact between the bound probes and relevant residues of the gamma-loop is very unlikely. Thus we have identified an allosteric interaction that couples the active site of thrombin to the gamma-loop. An interaction of this nature may be one way in which thrombomodulin modulates the reactivity of thrombin. PMID:8457193

Parry, M A; Stone, S R; Hofsteenge, J; Jackman, M P

1993-03-15

110

Atorvastatin neutralises the thrombin-induced tissue factor expresion in endothelial cells via geranylgeranyl pyrophosphate  

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Statins may have beneficial effects in atherogenesis given their antithrombotic properties involving non-lipid mechanisms that modify endothelial function of tissue factor induction by thrombin. In this study, we investigate the effect of atorvastatin on tissue factor (TF) activity in thrombin-stimulated endothelial cells and its regulation through mevalonate or its derivatives. First subculture of human umbilical endothelial cells was used for this study. Cells were treated with thrombin and atorvastatin for different time intervals and dosage. Tissue factor activity was measured as Factor Xa generation induced by Tissue Factor-Factor VIIa complex on confluent cells. Our results show that atorvastatin prevents the thrombin-induced up-regulation of tissue factor activity in a concentration-dependent manner. Mevalonate and geranylgeranyl pyrophosphate reversed this inhibitory effect of atorvastatin on tissue factor activity, while the presence of farnesyl pyrophosphate did not prevent the atorvastatin effect on thrombin-induced tissue factor activity. Rho-kinase inhibitor did not affect the thrombin stimulation of tissue factor activity. High amount of hydrophobic isoprenoid groups decreases the thrombin-induced TF activity and may promote endothelial cell anti-thrombotic action. Rho kinase pathways do not have a major role in the thrombin-mediated TF activity. The inhibitory effect of atorvastatin on thrombin-induced TF activity was partially reversed by MVA and GGPP but not FPP.

Vila, Virtudes; Ferrando, Marcos; Reganon, Edelmiro

2010-01-01

111

Topical haemostatic agents for skin wounds: a systematic review  

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Full Text Available Abstract Background Various agents and techniques have been introduced to limit intra-operative blood loss from skin lesions. No uniformity regarding the type of haemostasis exists and this is generally based on the surgeon's preference. To study the effectiveness of haemostatic agents, standardized wounds like donor site wounds after split skin grafting (SSG appear particularly suitable. Thus, we performed a systematic review to assess the effectiveness of haemostatic agents in donor site wounds. Methods We searched all randomized clinical trials (RCTs on haemostasis after SSG in Medline, Embase and the Cochrane Library until January 2011. Two reviewers independently assessed trial relevance and quality and performed data analysis. Primary endpoint was effectiveness regarding haemostasis. Secondary endpoints were wound healing, adverse effects, and costs. Results Nine relevant RCTs with a fair methodological quality were found, comparing epinephrine, thrombin, fibrin sealant, alginate dressings, saline, and mineral oil. Epinephrine achieved haemostasis significantly faster than thrombin (difference up to 2.5 minutes, saline or mineral oil (up to 6.5 minutes. Fibrin sealant also resulted in an up to 1 minute quicker haemostasis than thrombin and up to 3 minutes quicker than placebo, but was not directly challenged against epinephrine. Adverse effects appeared negligible. Due to lack of clinical homogeneity, meta-analysis was impossible. Conclusion According to best available evidence, epinephrine and fibrin sealant appear superior to achieve haemostasis when substantial topical blood loss is anticipated, particularly in case of (larger SSGs and burn debridement.

Ubbink Dirk T

2011-07-01

112

Pulmonary epithelial clearance of 99mTc-DTPA after thrombin-induced pulmonary microembolism  

International Nuclear Information System (INIS)

We investigated the effect of thrombin-induced pulmonary microembolism on the pulmonary clearance rate of aerosolized 99mTc diethylenetriamine pentaacetic acid (99mTc-DTPA) in awake, chronically prepared sheep. Chest activity was recorded after administration of a 0.44 micron aerosol of 99mTc-DTPA. Decay-corrected data were fit to an exponential and expressed as percent decrease per min (%/min). Sheep were given alpha-thrombin intravenously (80 U/kg for 10 min) 60 min after the aerosol administration. The clearance rate prior to alpha-thrombin was 0.35 +/- 0.05 %/min (mean +/- SEM). During alpha-thrombin administration, the clearance rate increased to 5.84 +/- 0.70 %/min (p less than 0.001 from baseline), but returned to 0.41 +/- 0.06 %/min within 30 min after the end of the thrombin infusion. The increased clearance rate during alpha-thrombin administration was not due to increased lung volume since alpha-thrombin did not change functional residual capacity. Moreover, the clearance rate was unchanged during gamma-thrombin administration, which does not induce coagulation, or during alpha-thrombin challenge in defibrinogenated animals. alpha-thrombin administration in neutrophil-depleted sheep caused a transient increase in DTPA clearance similar to that in control sheep, suggesting that the increase occurred independently of neutrophils. The results indicate that alpha-thrombin causes a large, transient increase in 99mTc-DTPA clearance, which may be the result of increased epithelial permeability. This response is dependent on the activation of intravascular coagulation

1986-01-01

113

Thrombin drives tumorigenesis in colitis-associated colon cancer.  

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The established association between inflammatory bowel disease and colorectal cancer underscores the importance of inflammation in colon cancer development. On the basis of evidence that hemostatic proteases are powerful modifiers of both inflammatory pathologies and tumor biology, gene-targeted mice carrying low levels of prothrombin were used to directly test the hypothesis that prothrombin contributes to tumor development in colitis-associated colon cancer (CAC). Remarkably, imposing a modest 50% reduction in circulating prothrombin in fII+/- mice, a level that carries no significant bleeding risk, dramatically decreased adenoma formation following an azoxymethane/dextran sodium sulfate challenge. Similar results were obtained with pharmacologic inhibition of prothrombin expression or inhibition of thrombin proteolytic activity. Detailed longitudinal analyses showed that the role of thrombin in tumor development in CAC was temporally associated with the antecedent inflammatory colitis. However, direct studies of the antecedent colitis showed that mice carrying half-normal prothrombin levels were comparable to control mice in mucosal damage, inflammatory cell infiltration, and associated local cytokine levels. These results suggest that thrombin supports early events coupled to inflammation-mediated tumorigenesis in CAC that are distinct from overall inflammation-induced tissue damage and inflammatory cell trafficking. That prothrombin is linked to early events in CAC was strongly inferred by the observation that prothrombin deficiency dramatically reduced the formation of very early, precancerous aberrant crypt foci. Given the importance of inflammation in the development of colon cancer, these studies suggest that therapeutic interventions at the level of hemostatic factors may be an effective means to prevent and/or impede colitis-associated colon cancer progression. PMID:24710407

Turpin, Brian; Miller, Whitney; Rosenfeldt, Leah; Kombrinck, Keith; Flick, Matthew J; Steinbrecher, Kris A; Harmel-Laws, Eleana; Mullins, Eric S; Shaw, Maureen; Witte, David P; Revenko, Alexey; Monia, Brett; Palumbo, Joseph S

2014-06-01

114

Wound healing and the immune response in swine treated with a hemostatic bandage composed of salmon thrombin and fibrinogen  

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We investigated the inflammatory response in pigs exposed to salmon fibrinogen/thrombin dressings. Animals were exposed to the material in 3 ways: (a) thrombin and fibrinogen were injected intravenously, (b) dual full-thickness skin lesions were surgically created on the dorsal aspect of the swine and treated with the fibrinogen/thrombin bandage and a commercial bandage or (c) a fibrinogen/thrombin bandage was inserted through an abdominal incision into the peritoneal cavity. Blood was collec...

Rothwell, Stephen W.; Sawyer, Evelyn; Dorsey, Jennifer; Flournoy, William S.; Settle, Timothy; Simpson, David; Cadd, Gary; Janmey, Paul; White, Charles; Szabo, Kathleen A.

2009-01-01

115

Doppler ultrasound-guided percutaneous thrombin injection for treating femoral pseudoaneurysms  

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Objective: To evaluate the success rate of percutaneous injectionof thrombin, guided by Doppler ultrasound to treat femoralpseudoaneurysms. Methods: Twenty-three patients withfemoral pseudoaneurysms were treated with ultrasound-guidedthrombin injection, between September 2003 and October 2007.Pseudoaneurysm size, dose of thrombin used, result of therapy andcomplications were prospectively documented. Other aspects analyzedincluded the type of procedure that caused the pseudoaneurysm(diagnosti...

2008-01-01

116

Poor prognosis of hypocoagulability assessed by thrombin generation assay in disseminated intravascular coagulation.  

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Overall assessment of the hemostatic system including procoagulant and anticoagulant changes may help assess the clinical status and prognosis of disseminated intravascular coagulation (DIC). The thrombin generation assay provides useful information about the global hemostatic status. Therefore, we measured several parameters of global hemostatic potential by the thrombin generation assay in patients suspected of having DIC. A total of 114 patients with suspected DIC were included. The thrombin generation assay was performed on the calibrated automated thrombogram using tissue factor with or without the addition of thrombomodulin, showing three parameters: lag time, endogenous thrombin potential (ETP), and peak thrombin. Both 1 and 5?pmol/l tissue factor-stimulated ETP and peak thrombin were well correlated with DIC severity. Interestingly, antithrombin level greatly affected ETP, whereas protein C influenced lag time. Prognostic analysis revealed that the area under the curve of peak thrombin stimulated by 1?pmol/l tissue factor was superior to that of D-dimer. Moreover, multivariate Cox analysis showed that the lag time and time to peak with both 1 and 5?pmol/l tissue factor were independent prognostic markers. ETP and peak thrombin well reflect DIC severity. Hypocoagulability manifesting as prolonged lag time and time to peak is expected to be an independent prognostic marker in DIC. PMID:24675694

Lee, Kyunghoon; Kim, Ji-Eun; Kwon, Jihyun; Kim, Inho; Yoon, Sung-Soo; Park, Seonyang; Han, Kyou-Sup; Kim, Hyun Kyung

2014-04-01

117

The discovery of orally available thrombin inhibitors: optimisation of the P1 pharmacophore.  

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Thrombin inhibitors have been designed with the replacement of the strongly basic guanidine P1 pharmocophore with a group that exploits the lipophilicity of the S1 pocket. The approach has lead to the discovery of potent thrombin inhibitors demonstrating good intra-duodenal absorption. PMID:10328293

Ambler, J; Bentley, D; Brown, L; Dunnet, K; Farr, D; Janus, D; Le Grand, D; Menear, K; Mercer, M; Talbot, M; Tweed, M; Wathey, B

1999-04-19

118

Combined thrombin-collagen injection for the management of an iatrogenic pseudoanuerysm in the popliteal region  

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Pseudoaneurysm formation is a rare but recognized complication of total knee arthroplasty (TKR), with fewer than 20 cases described in the literature. Multiple management techniques have been described for such pseudoaneurysms. As thrombin injection is an established technique, we report a case of a post-TKR tibioperoneal pseudoaneurysm successfully occluded via percutaneous injection of a dual thrombin-collagen preparation.

2012-01-01

119

Role of the A chain in thrombin function  

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The A chain of thrombin is covalently linked to the catalytic B chain but is separate from any known epitope for substrate recognition. In this study we present the results of the Ala replacement of 12 charged residues controlling the stability of the A chain and its interaction with the B chain. Residues Arg4 and Glu8 play a significant role in substrate recognition, even though they are located >20 Å away from residues of the catalytic triad, the primary specificity pocket and the Na+ site...

Papaconstantinou, M. E.; Bah, A.; Di Cera, E.

2008-01-01

120

Women's Health Topics  

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... Women's Health Topics ? - Resources for You Women's Health Topics Take Time to Care about Your Health . Women ... Health Mammograms Menopause Pregnancy Safe Medication Use Other Topics like cosmetics, nutrition, and HPV - Other Resources womenshealth. ...

 
 
 
 
121

Thrombin activatable fibrinolysis inhibitor: a putative target to enhance fibrinolysis.  

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Thrombin activatable fibrinolysis inhibitor (TAFI) was discovered two decades ago consequent to the identification of an unstable carboxypeptidase (CPU) formed upon thrombin activation of its proenzyme. The antifibrinolytic effects of the activated form (TAFIa, CPU) are linked with its capacity to remove C-terminal lysines from the surface of the fibrin clot. A distinctive characteristic of TAFIa is its temperature-dependent conformational instability: TAFIa activity spontaneously decays with an apparent half-life of 8 to 15 minutes at 37°C. A variety of studies has demonstrated a role for TAFI/TAFIa in venous and arterial diseases. In addition, a role for TAFI/TAFIa in inflammation and cell migration has also been shown. Because TAFI/TAFIa is a potential risk factor for thrombotic disorders, many inhibitors, both at the level of activation or at the level of activity, have been developed and were proven to exhibit a profibrinolytic effect in animal models. Pharmacologically active inhibitors of the TAFI/TAFIa system may open new ways for the prevention of thrombotic diseases or for the establishment of adjunctive treatments during thrombolytic therapy. PMID:23457049

Vercauteren, Ellen; Gils, Ann; Declerck, Paul J

2013-06-01

122

Topic: A Literature Review  

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Full Text Available There is a wide discussion for Chinese topic structure and topic-sentence acquisition in Second Language Acquisition since Li & Thompson (1976. This paper reviews the contribution made by Li & Thompson on topic and later researches on the basis of them. The relationship between subject and topic also is concentrated.

Dandan Zhang

2009-08-01

123

Topic: A Literature Review  

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There is a wide discussion for Chinese topic structure and topic-sentence acquisition in Second Language Acquisition since Li & Thompson (1976). This paper reviews the contribution made by Li & Thompson on topic and later researches on the basis of them. The relationship between subject and topic also is concentrated.

Dandan Zhang

2009-01-01

124

Substitution of valine for glycine-558 in the congenital dysthrombin thrombin Quick II alters primary substrate specificity  

International Nuclear Information System (INIS)

Thrombin Quick II is one of two dysfunctional forms of thrombin derived from the previously described congenital dysprothrombin prothrombin Quick. Thrombin Quick II does not clot fibrinogen, hydrolyze p-nitroanilide substrates of thrombin, or bind N2-[5-(dimethylamino)naphthalene-1-sulfonyl]arginine N,N-(3-ethyl-1,5-pentanediyl)amide, a high-affinity competitive inhibitor of thrombin. To determine the structural alteration in thrombin Quick II, the reduced, carboxymethylated protein was hydrolyzed by a lysyl endopeptidase. A peptide not present in a parallel thrombin hydrolysate was identified by reverse-phase chromatography. This Gly residue, which is highly conserved in the chymotrypsin family of serine proteases, forms part of the substrate binding pocket for bulky aromatic and basic side chains in chymotrypsin and trypsin, respectively. However, in porcine elastase 1, the corresponding residue is threonine. Consistent with the identified structural alteration, thrombin Quick II incorporates [3H]diisopropyl fluorophosphate stoichiometrically and hydrolyzes the elastase substrate succinyl-Ala-Ala-Pro-Leu-p-nitroanilide with a relative kcat/KM of 0.14 when compared to thrombin. This results from a 3-fold increase in KM and a 2.5-fold decrease in kcat for thrombin Quick II when compared to thrombin acting on the same substrate. These results and those of other investigators studying mutant trypsins support the conclusion that the catalytic activity of serine proteases is very sensitive to structural alterations in the primary substrate binding pocket

1989-03-07

125

A convenient sandwich assay of thrombin in biological media using nanoparticle-enhanced fluorescence polarization.  

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A new aptamer biosensor was presented for the detection of thrombin in this work, which was based on fluorescence polarization (FP) using silica nanoparticles as enhancement probe. The silica nanoparticles covered by streptavidin were tagged with a thrombin aptamer (5'-biotin-GGTTGGTGTGGTTGG-3'), which was bound to the surface of silica nanoparticle through the specific interaction between streptavidin and biotin. In the presence of thrombin, it induced the aptamer to form quadruplex structure. When the other thrombin aptamer labeled with fluorescein (5'-FAM-AGTCCGTGGTAGGGCAGGTTGGGGTGACT-3') was added to the above system, a sandwich structure can form at the surface of silica nanoparticles. The fluorescence polarization was therefore enhanced and quantification between fluorescence polarization signal and concentration of thrombin was built. The sensor provided a linear range from 0.6 to 100 nM for thrombin with a detection limit of 0.20 nM (3.29 SB/m, according to the recent recommendation of IUPAC) in a homogeneous media. The same linear range was obtained in spiked human serum samples with a slightly higher detection limit (0.26 nM), demonstrating high anti-interference of the sensor in a complex biological sample matrix. And the sensor can be used to monitor spiked concentration of thrombin level in real human plasma with satisfactory results obtained. PMID:24508546

Yue, Qiaoli; Shen, Tongfei; Wang, Lei; Xu, Shuling; Li, Haibo; Xue, Qingwang; Zhang, Yuanfu; Gu, Xiaohong; Zhang, Shuqiu; Liu, Jifeng

2014-06-15

126

Heparin coating of tantalum coronary stents reduces surface thrombin generation but not factor IXa generation.  

Science.gov (United States)

In the present study we used an in-vitro technique to examine initiation and propagation of blood coagulation at the surface of tantalum coronary stents exposed to flowing platelet-rich and platelet-free plasma. The time course of factor IXa production at the surface of the stent was not influenced by platelets. In spite of a significant factor IXa production, no thrombin activity was detected when the tantalum stent was exposed to platelet-free plasma; only when the stent was exposed to platelet-rich plasma was extensive thrombin production observed. These findings indicate that tantalum triggers blood coagulation, but that (adherent) platelets are essential for thrombin generation. Heparin-coated tantalum stents exposed to flowing platelet-rich plasma showed that factor IXa generation was slightly reduced compared with the bare stent. However, the heparin coating drastically delayed the onset of thrombin generation and largely reduced the steady-state production of thrombin. We found a clear relationship between the antithrombin binding capacity and the antithrombogenic potential of the heparin-coated stents. The mode of action of immobilized heparin is thought to abrogate thrombin generation by inhibiting thrombin-dependent positive feedback reactions at the surface of the coronary stent. PMID:9712292

Blezer, R; Cahalan, L; Cahalan, P T; Lindhout, T

1998-07-01

127

Coiled-coil peptide based sensor for ultra-sensitive thrombin detection.  

Science.gov (United States)

Comb structured gold microelectrode array (CSGMA) functionalized with self-assembled monolayer of thiol terminated coiled-coil peptide (CCP) linked together by the thrombin specific cleavage site (Leu-Val-Pro-Arg-Gly-Ser) has been used to fabricate an ultrasensitive, disposable, electrochemical thrombin biosensor. CCP with thiol at one end provides the ease of CSGMA functionalization and the presence of thrombin specific peptide in the middle of coiled-coil peptide provides site for thrombin capture and detection. CCP/CSGMA electrodes were characterized using label-free electrochemical impedance (EIS) technique and exposed to solutions with different thrombin concentrations for its estimation. Results reveal that CCP/CSGMA electrodes have a limit of detection (LOD) of 10 fg/ml (28 fM) and are able to detect catalytic activity of thrombin within 30 min time frame. CCP/CSGMA electrodes were found to be selective against other IgG anti-bodies such as DO1 and HA. Thus, CCP/CSGMA electrodes provide high specificity toward thrombin detection and mechanistic details of binding and cleavage process. PMID:24355462

Kongsuphol, Patthara; Arya, Sunil K; Chung Wong, Chee; Polla, Lee Joseph; Park, Mi Kyoung

2014-05-15

128

Protamine sulfate down-regulates thrombin generation by inhibiting factor V activation.  

LENUS (Irish Health Repository)

Protamine sulfate is a positively charged polypeptide widely used to reverse heparin-induced anticoagulation. Paradoxically, prospective randomized trials have shown that protamine administration for heparin neutralization is associated with increased bleeding, particularly after cardiothoracic surgery with cardiopulmonary bypass. The molecular mechanism(s) through which protamine mediates this anticoagulant effect has not been defined. In vivo administration of pharmacologic doses of protamine to BALB\\/c mice significantly reduced plasma thrombin generation and prolonged tail-bleeding time (from 120 to 199 seconds). Similarly, in pooled normal human plasma, protamine caused significant dose-dependent prolongations of both prothrombin time and activated partial thromboplastin time. Protamine also markedly attenuated tissue factor-initiated thrombin generation in human plasma, causing a significant decrease in endogenous thrombin potential (41% +\\/- 7%). As expected, low-dose protamine effectively reversed the anticoagulant activity of unfractionated heparin in plasma. However, elevated protamine concentrations were associated with progressive dose-dependent reduction in thrombin generation. To assess the mechanism by which protamine mediates down-regulation of thrombin generation, the effect of protamine on factor V activation was assessed. Protamine was found to significantly reduce the rate of factor V activation by both thrombin and factor Xa. Protamine mediates its anticoagulant activity in plasma by down-regulation of thrombin generation via a novel mechanism, specifically inhibition of factor V activation.

Ni Ainle, Fionnuala

2009-08-20

129

Ostrich antithrombin III: kinetics and mechanism of inhibition of ostrich thrombin.  

Science.gov (United States)

A kinetic investigation of ostrich thrombin specificity, its regulation and evolutionary development in comparison to those of other well-characterised species may contribute to the understanding of the structure-function relationships of thrombin. Antithrombin III (ATIII) was purified from ostrich plasma by heparin-Sepharose and Super Q-650S chromatography. It exhibited a M(r) of 59.2K and a pI in the range of 5.2-6.0. The ostrich N-terminal sequence was compared to those of other known species and showed the highest identity with rabbit ATIII (31%). Inhibition studies included the interaction of ostrich and human ATIII with bovine, human and ostrich thrombin. At a 2:1 molar ratio of ostrich ATIII to enzyme, 20 and 40% remaining activity was found for bovine and ostrich thrombin, respectively. Ostrich thrombin exhibited a pH and temperature optimum of 9.0 and 60 degrees C, respectively. Hydrolysis of seven peptide p-nitroanilide substrates by ostrich thrombin revealed D-Phe-Pip-Arg-pNA (k(cat)/K(m)=9.65 microM(-1)s(-1)) as the substrate with the highest catalytic efficiency. The effect of monovalent cations on ostrich thrombin catalysis revealed enhanced activity with Na(+). The calculated K(i) values for the complex formation between ostrich thrombin and ostrich (9.29 x 10(-11)M) and human (9.66 x 10(-11)M) ATIII are comparable to reported results. The results obtained from the present study confirmed that ostrich thrombin and ATIII are closely related to the corresponding molecules of other species in terms of physicochemical and kinetic properties. PMID:12009311

Frost, Carminita L; Naudé, Ryno J; Muramoto, Koji

2002-09-01

130

Alpha-Lipoic Acid Inhibits Thrombin-Induced Fetal Membrane Weakening In Vitro  

Science.gov (United States)

Cytokine-mediated inflammation and abruption-induced thrombin generation are separately implicated in matrix metalloproteinase (MMP)-mediated weakening of fetal membranes (FM) leading to preterm premature rupture of the fetal membranes (PPROM). At term, FM of both labored vaginal and unlabored caesarian deliveries exhibit a weak zone overlying the cervix exhibiting ECM remodeling characterized by increased MMP9 protein and activity. We have reproduced these biochemical changes as well as FM weakening in vitro using tumor necrosis factor-alpha (TNF) and interleukin (IL)-1?, inflammatory cytokines implicated in PPROM. Additionally, we have reported that the antioxidant and NF?B inhibitor alpha-lipoic Acid (LA) blocks these TNF-induced effects. We now present the first direct evidence that thrombin also can induce FM weakening in vitro, and LA treatment inhibits this thrombin-induced weakening. Full thickness FM fragments from unlabored caesarian deliveries were incubated with increasing doses of thrombin (0–100 u/ml) for 48h. Fragments were then strength tested (breaking force and work to rupture) using our published methodology. MMP3 and 9 levels in tissue extracts were determined by Western blot and densitometry. To determine the effect of LA, FM fragments were incubated with control medium or 10 u/ml thrombin, with or without 0.25mM LA. Strength testing and MMP induction was determined. Thrombin induced a dose-dependent decrease in FM strength (42% baseline rupture force and 45% work to rupture) coupled with a dose-dependent increase in MMP3 and 9 expression (all p<.001). Treatment of FM with 0.25mM LA completely inhibited thrombin-induced FM weakening and MMP expression (all p<.001). Thrombin treatment of cultured FM induces mechanical weakening and increased MMP3 and 9. Treatment of FM with LA inhibits these thrombin-induced effects. We speculate LA may prove clinically useful in prevention of PPROM associated with abruption.

Moore, RM; Schatz, F; Kumar, D; Mercer, BM; Abdelrahim, A; Rangaswamy, N; Bartel, C; Mansour, JM; Lockwood, CJ; Moore, JJ

2010-01-01

131

High thrombin concentrations in fibrin sealants induce apoptosis in human keratinocytes.  

Science.gov (United States)

Over the last century many studies have been performed to assess the impact of fibrin sealant (FS) components on cells. Because of the noncovalent bonding of thrombin to fibrin during fibrin clot formation, we wanted to further evaluate the impact of fibrin bound thrombin on cell viability. Initially, we quantified the activity of thrombin in three different, commercially available FS. This information was used to prepare fibrin clots covering a range of thrombin concentrations from 4 to 820 IU mL(-1), but which were identical with respect to all other constituents. Although these fibrin clots did not differ in their three-dimensional structure, clots prepared with highly concentrated thrombin (820 IU mL(-1)) failed to support adhesion and spreading of primary human keratinocytes (NHEK). The number of attached cells was also significantly reduced on high thrombin activity clots. We hypothesized that these observations are not only the consequence of decreased proliferation but of apoptotic mechanisms, since the expression of cleaved caspase 3 and 7 was strongly enhanced on fibrin clots with high thrombin activity. This was accompanied by an induction of expression of Trail-R2 which is a receptor known to mediate apoptosis signals. Blocking of thrombin activity by hirudin led to an improvement of cell morphology and to an increase in number of attached cells. In addition, the induction of caspase 3 and 7 was also reduced. Thus, here we report for the first time that fibrin bound thrombin does not only decrease proliferation (as already published by others), it also does induce NHEK apoptosis when present at high concentrations. PMID:22359340

Gugerell, Alfred; Schossleitner, Klaudia; Wolbank, Susanne; Nürnberger, Sylvia; Redl, Heinz; Gulle, Heinz; Goppelt, Andreas; Bittner, Michaela; Pasteiner, Waltraud

2012-05-01

132

Gold nanoparticles conjugates-amplified aptamer immunosensing screen-printed carbon electrode strips for thrombin detection.  

Science.gov (United States)

Thrombin plays the role in cardiovascular diseases and regulates many processes in inflammation and could be a feature of many pathological conditions, including the thromboembolic disease, cancer and neurodegenerative diseases. An ultrasensitive and amplified electrochemical sandwich assay using screen-printed carbon electrode (SPCE) strips for thrombin detection was established in this study. The conductivity and sensing performance of the carbon electrodes were enhanced by using gold nanoparticles (AuNPs). The aptamer addressed on the strips was used as a primary probe to capture thrombin in the detected samples. An amplifier was invented for recognizing thrombin captured on the SPCE, which is the multiple molecules of anti-thrombin antibody (Ab) and horseradish peroxidase (HRP) co-modified AuNPs (AuNPs/Ab-HRP). Hydrogen peroxide was used as the substrate for HRP and then the response current (RC) could be detected. The optimization of these AuNPs conjugates-amplified aptamer immunosensing SPCE strips was conducted for thrombin detection. The detection sensitivity showed a linear relation between RC and thrombin concentration in the range of 10pM-100nM, and limit of detection (LOD) was 1.5pM. The fabricated AuNPs/Ab-HRP-amplified aptamer immunosensing SPCE strips were further used to detect thrombin in human serum with a linear range of 100pM-100nM. This study provided the promising SPCE strips with highly sensitive and rapid detection for thrombin by the electrochemical aptasensor combined with AuNPs conjugates for amplifying the detection signal. PMID:24912033

Yeh, Fang-Yuan; Liu, Ting-Yu; Tseng, I-Hua; Yang, Chung-Wei; Lu, Li-Che; Lin, Chih-Sheng

2014-11-15

133

Topical report review status  

International Nuclear Information System (INIS)

This report provides industry with procedures for submitting topical reports, guidance on how the U.S. Nuclear Regulatory Commission (NRC) processes and responds to topical report submittals, and an accounting, with review schedules, of all topical reports currently accepted for review schedules, of all topical reports currently accepted for review by the NRC. This report will be published annually. Each sponsoring organization with one or more topical reports accepted for review copies

1997-01-01

134

Topical report review status  

Energy Technology Data Exchange (ETDEWEB)

This report provides industry with procedures for submitting topical reports, guidance on how the U.S. Nuclear Regulatory Commission (NRC) processes and responds to topical report submittals, and an accounting, with review schedules, of all topical reports currently accepted for review schedules, of all topical reports currently accepted for review by the NRC. This report will be published annually. Each sponsoring organization with one or more topical reports accepted for review copies.

NONE

1997-08-01

135

PROTON BRIDGING IN THE INTERACTIONS OF THROMBIN WITH HIRUDIN AND ITS MIMICS†  

Science.gov (United States)

Thrombin is the pivotal serine protease enzyme in the blood cascade system and thus a target of drug design for control of its activity. The most efficient non-physiologic inhibitor of thrombin is hirudin, a naturally occurring small protein. Hirudin and its synthetic mimics employ a range of hydrogen bonding, salt bridging and hydrophobic interactions with thrombin to achieve tight binding with Ki values in the nano- to femtomolar range. The one-dimensional 1H NMR spectrum carried out at 600 MHz reveals a resonance at 15.33 ppm downfield from silanes in complexes between human ?-thrombin and r-hirudin in pH 5.6-8.8 buffers and between 5 and 35 °C. There is also a resonance between 15.17 and 15.54 ppm seen in human ?-thrombin complexes with hirunorm IV, hirunorm V, an N?(Me)Arg-peptide, RGD-hirudin and N?-2-naphthylsulfonyl-glycyl-DL-4-amidinophenylalanyl-piperidide acetate salt (NAPAP), while there is no such low-field resonance observed in a complex of porcine trypsin and NAPAP. The chemical shifts suggest that these resonances represent H-bonded environments. H-donor acceptor distances in the corresponding H-bonds are estimated to be <2.7 Å. Addition of Phe-Pro-Arg-Chloromethylketone (PPACK) to a complex of human ?-thrombin with r-hirudin results in an additional signal at 18.03 ppm, which is 0.10 ppm upfield from one observed (Kovach, I. M. et al. Biochemistry 2009, 48, 7296–7304) for thrombin covalently modified with PPACK. In contrast, the peak at 15.33 ppm remains unchanged. The fractionation factors for the thrombin-hirudin type complexes are near 1.0 within 20% error. The most likely site of the short H-bond in thrombin complexes with the hirudin family of inhibitors is in the hydrophobic patch of the C-terminus of hirudin where Glu57’ and Glu58’ are embedded and interact with Arg75 and Arg77 and their solvate water (on thrombin). Glu57’ and Glu58’ present in the hirudin family of inhibitors is a key binding epitope of fibrinogen, thrombin’s prime substrate, which lends substantial interest to the SHB as a binding element at the fibrinogen recognition site.

Kovach, Ildiko M.; Kakalis, Lazaros; Jordan, Frank; Zhang, Daoning

2013-01-01

136

[Polymer coatings with immobilized thrombin and peptides: preparation and use for wound healing].  

Science.gov (United States)

Polymer dressings with encapsulated thrombin or synthetic peptides which can mimic thrombin action are employed for wound healing. Paper describes the method for preparation of these hydrogel composites of PVCL-CaAlg [poly(N-vinyl caprolactam-calcium alginate). The effect of encapsulated thrombin/peptides on tissue repair process have beet investigatat in vivo experiments using a mouse model of wound healing. The developed dressings accelerated wound healing: thascan be used as a basis for creation of novel formulations with controlled drug release for wound therapy. PMID:12698556

Markvicheva, E A; Kuptsova, S V; Rumsh, L D; Dugina, T N; Lange, M A; Chistov, I V; Strukova, S M; Zubov, V P

2002-01-01

137

Lysosomotropic agents selectively potentiate thrombin-induced acid hydrolase secretion from platelets.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thrombin induces partial secretion (up to 60%) of beta-N-acetyl-D-hexosaminidase (EC 3.2.1.52) from untreated platelets. Preincubation of platelets with 10 mM NH4Cl for up to 2 hr resulted in a time-dependent and marked stimulation of thrombin-induced secretion of both this enzyme and other acid glycosidases from platelets. The enhancement of the thrombin-induced secretion was not due to cell lysis, and NH4Cl alone did not cause leakage of lysosomal enzymes into the medium. The effect could b...

Oost, B. A.; Smith, J. B.; Holmsen, H.; Vladutiu, G. D.

1985-01-01

138

Recombining WMAP: Beyond standard recombination  

CERN Multimedia

We place new constraints on sources of ionizing and resonance radiation at the epoch of the recombination process using the recent CMB temperature and polarization spectra coming from WMAP. We find that non-standard recombination scenarios are still consistent with the current data. In light of this we study the impact that such models can have on the determination of several cosmological parameters. In particular, the constraints on curvature and baryon density appear to be weakly affected by a modified recombination scheme. However, it may affect the current WMAP constraints on inflationary parameters like the spectral index and its running. Physically motivated models, like those based on primordial black hole or super heavy dark matter decay, are able to provide a good fit to the current data. Future observations in both temperature and polarization will be needed to more stringently test these models.

Bean, R; Silk, J; Bean, Rachel; Melchiorri, Alessandro; Silk, Joe

2003-01-01

139

VDJ recombination.  

Science.gov (United States)

The ability of lymphocyte receptor V, D and J gene segments to rearrange generates much of the receptor diversity that is the hallmark of the immune system. Naturally, the mechanisms of immunoglobulin and T-cell receptor gene recombination are of enormous interest. Here, Fred Alt and colleagues review current understanding of the process and speculate on future findings. PMID:1510813

Alt, F W; Oltz, E M; Young, F; Gorman, J; Taccioli, G; Chen, J

1992-08-01

140

Percutaneous Ultrasound Guided Thrombin Injection for Endoleaks: An Alternative  

International Nuclear Information System (INIS)

Endoleaks are now well-recognized complications of endovascular repair of abdominal aortic aneurysm and an incidence of up to 46% has been reported in the literature. These endoleaks can result in rupture of the aneurysmal sac with potentially serious consequences. A type 2 endoleak is the most common type with a feeding vessel reperfusing the aneurysm sac. Radiological treatment of such an endoleak usually involves coil or particle angioembolisation, but sometimes this can be difficult, especially if endovascular access to the feeding vessel is not straightforward. We describe and illustrate percutaneous ultrasound-guided thrombin injection in the treatment of a type 2 endoleak. In appropriate patients, this technique is simple to perform, and has low associated morbidity

2005-01-01

 
 
 
 
141

THE EVALUATION OF CLOTTING TIME IN BOVINE THROMBIN, REPTILASE ® , AND THROMBIN-LIKE FRACTION OF Crotalus durissus terrificus VENOM USING BOVINE, EQUINE, OVINE, BUBALINE AND HUMAN CRYOPRECIPITATES  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of this study was to evaluate the effects of the thrombin-like fraction of Crotalus durissus terrificus venom, Reptilase , and bovine thrombin of fibrinogen pools on bovine, equine, ovine, bubaline and human cryoprecipitates. The authors also made a comparative study between animal and human cryoprecipitates to see if any there was any possibility of future use in medicine. Fibrinogen levels in cryoprecipitate were studied using 48 blood samples obtained as follows:12 samples from humans, 9 from bovine, 10 from equine, 10 from ovine and 7 from bubaline. The results obtained showed average levels of 375.50 mg % for humans, 218.33 mg % for bovine, 240.80 mg % for equine, 267.70 mg % for ovine and 664.00 mg % for bubaline. Upon the formation of pools of human and animal fibrinogens, the following results were obtained: 435 mg % for humans, 444 mg % for bovine, 337 mg % for equine, 390 mg % for ovine and 530 mg % for bubaline. Statistical analysis (using the analysis of variance for entirely randomized experiment for the calculation of F statistics demonstrated that the bubaline fibrinogen level was higher than that of human, and both were higher than those of ovine, equine, and bovine. Clotting times were determined using different dilutions of bovine thrombin, thrombin-like fraction of Crotalus durissus terrificus venom, and Reptilase . Comparing these clotting times, results for human and bovine were found to be very similar, whereas using equine, ovine, and bubaline the results above a dilution of 1:3 were markedly different. The results obtained permitted the following conclusions to be drawn show that: 1 bovine thrombin presented better interactivity with fibrinogen extracted both from human and bovine cryoprecipitates; 2 there was similar behavior when bovine thrombin was substituted for Reptilase and for the thrombin-like fraction of Crotalus durissus terrificus venom; 3 cryoprecipitate from bovine can, in special circumstances, substitute human cryoprecipitate in medical practice; 4 human and bovine cryoprecipitates can be used with both Reptilase and Crotalus durissus terrificus fractions using a dilution up to 1:5; 5 the use of bovine cryoprecipitate can be recommended using either bovine thrombin, Reptilase , or thrombin-like fraction of Crotalus durissus terrificus venom.

I. A. THOMAZINI-SANTOS

1998-01-01

142

THE EVALUATION OF CLOTTING TIME IN BOVINE THROMBIN, REPTILASE ® , AND THROMBIN-LIKE FRACTION OF Crotalus durissus terrificus VENOM USING BOVINE, EQUINE, OVINE, BUBALINE AND HUMAN CRYOPRECIPITATES  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english The objective of this study was to evaluate the effects of the thrombin-like fraction of Crotalus durissus terrificus venom, Reptilase , and bovine thrombin of fibrinogen pools on bovine, equine, ovine, bubaline and human cryoprecipitates. The authors [...] also made a comparative study between animal and human cryoprecipitates to see if any there was any possibility of future use in medicine. Fibrinogen levels in cryoprecipitate were studied using 48 blood samples obtained as follows:12 samples from humans, 9 from bovine, 10 from equine, 10 from ovine and 7 from bubaline. The results obtained showed average levels of 375.50 mg % for humans, 218.33 mg % for bovine, 240.80 mg % for equine, 267.70 mg % for ovine and 664.00 mg % for bubaline. Upon the formation of pools of human and animal fibrinogens, the following results were obtained: 435 mg % for humans, 444 mg % for bovine, 337 mg % for equine, 390 mg % for ovine and 530 mg % for bubaline. Statistical analysis (using the analysis of variance for entirely randomized experiment for the calculation of F statistics) demonstrated that the bubaline fibrinogen level was higher than that of human, and both were higher than those of ovine, equine, and bovine. Clotting times were determined using different dilutions of bovine thrombin, thrombin-like fraction of Crotalus durissus terrificus venom, and Reptilase . Comparing these clotting times, results for human and bovine were found to be very similar, whereas using equine, ovine, and bubaline the results above a dilution of 1:3 were markedly different. The results obtained permitted the following conclusions to be drawn show that: 1) bovine thrombin presented better interactivity with fibrinogen extracted both from human and bovine cryoprecipitates; 2) there was similar behavior when bovine thrombin was substituted for Reptilase and for the thrombin-like fraction of Crotalus durissus terrificus venom; 3) cryoprecipitate from bovine can, in special circumstances, substitute human cryoprecipitate in medical practice; 4) human and bovine cryoprecipitates can be used with both Reptilase and Crotalus durissus terrificus fractions using a dilution up to 1:5; 5) the use of bovine cryoprecipitate can be recommended using either bovine thrombin, Reptilase , or thrombin-like fraction of Crotalus durissus terrificus venom.

I. A., THOMAZINI-SANTOS; M. J. S. M., GIANNINI; E., TOSCANO; P.E.A., MACHADO; C. R. G., LIMA; B., BARRAVIERA.

143

The technique of measuring thrombin generation with fluorescent substrates: 4. The H-transform, a mathematical procedure to obtain thrombin concentrations without external calibration.  

Science.gov (United States)

In fluorogenic thrombin generation (TG) experiments, thrombin concentrations cannot be easily calculated from the rate of the fluorescent signal increase, because the calibration coefficient increases during the experiment, due to substrate consumption and quenching of the fluorescent signal by the product. Continuous, external calibration via an in a parallel sample therefore was hitherto required for an accurate calculation of the TG curve. A technique is presented that allows mathematical transformation of experimental fluorescence intensities into "ideal" data, i.e. in the data that would have been obtained if substrate consumption and quenching by the product would not play a role. The method applies to fluorescence intensities up to 90% of the maximal fluorescent signal corresponding to total substrate conversion and thereby covers the entire region of interest encountered in practice. The first derivative of the transformed signal can then be converted into thrombin concentrations via a conventional, fixed calibration factor. This calibration factor can be obtained from a separate experiment but also by measuring the amidolytic activity of the alpha(2)macroglobulin-thrombin complex present in the reaction mixture ("serum") after thrombin generation is over. This method halves the amount of sample required per experiment. PMID:19132205

Coen Hemker, H; Hemker, Pieter W; Al Dieri, Raed

2009-01-01

144

Reversal of trauma-induced amnesia in mice by a thrombin receptor antagonist.  

Science.gov (United States)

Minimal traumatic brain injury (mTBI) is associated with the existence of retrograde amnesia and microscopic bleeds containing activated coagulation factors. In an mTBI model, we report that thrombin induces amnesia through its receptor protease-activated receptor 1 (PAR-1). Thrombin activity was significantly elevated (32 %, p?Amnesia was assessed by the novel object recognition test in mTBI animals and in animals injected intracerebroventricularly (ICV) with either thrombin or a PAR-1 agonist 1 h after the acquisition phase. Saline-injected controls had a preference index of over 0.3 while mTBI animals and those injected with thrombin or the PAR-1 agonist spent equal time with both objects indicating no recall of the object presented to them 24 h previously (p?amnesia following mTBI, revealing a novel therapeutic target for the cognitive effects of brain trauma. PMID:24352712

Itzekson, Zeev; Maggio, Nicola; Milman, Anat; Shavit, Efrat; Pick, Chaim G; Chapman, Joab

2014-05-01

145

Human Thrombin Detection Through a Sandwich Aptamer Microarray: Interaction Analysis in Solution and in Solid Phase  

Directory of Open Access Journals (Sweden)

Full Text Available We have developed an aptamer-based microarray for human thrombin detection exploiting two non-overlapping DNA thrombin aptamers recognizing different exosites of the target protein. The 15-mer aptamer (TBA1 binds the fibrinogen-binding site, whereas the 29-mer aptamer (TBA2 binds the heparin binding domain. Extensive analysis on the complex formation between human thrombin and modified aptamers was performed by Electrophoresis Mobility Shift Assay (EMSA, in order to verify in solution whether the chemical modifications introduced would affect aptamers/protein recognition. The validated system was then applied to the aptamer microarray, using the solid phase system devised by the solution studies. Finally, the best procedure for Sandwich Aptamer Microarray (SAM and the specificity of the sandwich formation for the developed aptasensor for human thrombin were optimized.

Alice Sosic

2011-10-01

146

A fluorescent sandwich assay for thrombin using aptamer modified magnetic beads and quantum dots  

International Nuclear Information System (INIS)

We describe an aptamer-based sandwich assay for thrombin by using a pair of thrombin-binding aptamers, namely one 15-mer aptamer (denoted as Apt15) and one 29-mer aptamer (denoted as Apt29). Either Apt29 or Apt15 can be used as capture aptamers on magnetic beads or reporter aptamers on the quantum dots to form the sandwich complex. Detection of thrombin is achieved by the fluorescent measurement of quantum dots in the sandwich complex. The choice of capture aptamers and reporter aptamers, and the effect of the addition order of the aptamers modified magnetic beads and the aptamers modified quantum dots were investigated. Detection of 0.05 nM thrombin was accomplished. The proteins hemoglobin, lysozyme, and transferrin did not interfere in this assay. (author)

2012-09-01

147

Behavior of Homologous exp 125 I Fibrinogen after Thrombin and Ancrod Infusion in Rabbits.  

Science.gov (United States)

The behavior of radioactively labelled fibrinogen after infusion of thrombin or ancrod is investigated. Common factors and differences in the behaviour of fibrinogen after infusion of these two enzymes, which act proteolytically on the fibrinogen, are dea...

R. Setter

1977-01-01

148

Behaviour of homologous 125I fibrinogen after thrombin and ancrod infusion in rabbits  

International Nuclear Information System (INIS)

The behaviour of radioactively labelled fibrinogen after infusion of thrombin or ancrod is investigated. Common factors and differences in the behaviour of fibrinogen after infusion of these two enzymes, which act proteolytically on the fibrinogen, are dealt with. Rabbits received an i.v. injection of homologous 125I-fibrinogen 3 days before ancrod or thrombin infusion. On the day of the experiments, one group of animals received an ancrod infusion (1.5 U/kg body weight for 30 minutes), the other a thrombin infusion (600 U/kg body weight for 60 minutes). Intravenous ancrod and thrombin infusions lowered the fibrinogen level to 30% or 50% of the initial value due to intravascular coagulation. About 50% of the 125I fibrinogen was transformed after ancrod exposure into a non-coagulating fraction of fibrinogen derivatives which produces no fibrinolytic decomposition products. (orig./AJ)

1977-01-01

149

Interaction of hirudin with thrombin: Identification of a minimal binding domain of hirudin that inhibits clotting activity  

Energy Technology Data Exchange (ETDEWEB)

Hirudin, isolated from the European leech Hirudo medicinalis, is a potent inhibitor of thrombin, forming an almost irreversible thrombin-hirudin complex. Previously, the authors have shown that the carboxyl terminus of hirudin (residues 45-65) inhibits clotting activity and without binding to the catalytic site of thrombin. In the present study, a series of peptides corresponding to this carboxyl-terminal region of hirudin have been synthesized, and their anticoagulant activity and binding properties to thrombin were examined. Binding was assessed by their ability to displace {sup 125}I-hirudin 45-65 from Sepharose-immobilized thrombin and by isolation of peptide-thrombin complexes. They show that the carboxyl-terminal 10 amino acid residues 56-65 (Phe-Glu-Glu-Ile-Pro-Glu-Glu-Tyr-Leu-Gln) are minimally required for binding to thrombin and inhibition of clotting. Phe-56 was critical for maintaining anticoagulant activity as demonstrated by the loss of activity when Phe-56 was substituted with D-Phe, Glu, or Leu. In addition, they found that the binding of the carboxyl-terminal peptide of hirudin with thrombin was associated with a significant conformational change of thrombin as judged by circular dichroism. This conformational change might be responsible for the loss of clotting activity of thrombin.

Mao, S.J.T.; Yates, M.T.; Owen, T.J.; Krstenansky, J.L. (Merrell Dow Research Institute, Cincinnati, OH (USA))

1988-10-18

150

Exotic Recombination  

Energy Technology Data Exchange (ETDEWEB)

I review few examples of the numerous physical processes that might change the standard model of recombination. The high precision of current and future CMB data may allow the detection of these processes, that leave recognizable imprints on the angular power spectra. I review some of the results obtained in constraining i) a variation of the gravitational constant G ii) the presence of extra-sources of energetic photons in the primeval plasma and iii) annihilation of dark matter particles.

Galli, Silvia [Physics Department, Universita di Roma ' La Sapienza' , Ple Aldo Moro 2, 00185, Rome (Italy); Laboratoire Astroparticule et Cosmologie (APC), Universite Paris Diderot - 75205 PARIS cedex 13 (Italy)

2009-10-15

151

Percutaneous ultrasound-guided thrombin injection for the treatment of iatrogenic femoral artery pseudoaneurysms  

International Nuclear Information System (INIS)

Purpose: To audit our experience with ultrasound-guided thrombin injection for the treatment of iatrogenic femoral artery pseudoaneurysms. Methods: A retrospective study of 85 consecutive patients undergoing percutaneous ultrasound-guided thrombin injection of post-catheterization femoral pseudoaneurysms during the period January 2002 to May 2007. Results: Pseudoaneurysms had a mean maximum diameter of 3.3 cm (range 1.0-7.6 cm) and a mean neck width of 3.4 mm (range 1.0-7.0 mm). No statistically significant correlation existed between maximum diameter and neck width (Kendall's rank correlation tau b = -0.09, p = 0.5). The median dose of thrombin injected was 425 U (range 100-1500 U). The procedure resulted in complete sac thrombosis in 81 (95%) patients. Seventy-nine pseudoaneurysms thrombosed immediately after one injection, whereas two required a second thrombin injection. There were no procedural complications. The maximum diameter of the pseudoaneurysm was predictive of procedural success (Wilcoxon's rank sum test, p = 0.001) and of the 5 patients with a pseudoaneurysm measuring ?6 cm, ultrasound-guided thrombin injection was unsuccessful in 4 (4/5 versus 0/80, p < 0.0001, Fisher's exact test). Three of these necessitated implantation of a stent-graft, whereas one required repeated thrombin injection and coil placement. In contrast, the pseudoaneurysm neck width did not seem to relate to the success of the procedure. Conclusion: Percutaneous ultrasound-guided thrombin injection of is a quick, effective and safe treatment for iatrogenic femoral pseudoaneurysms. For larger pseudoaneurysms, although it is worth attempting more than one thrombin injection, endovascular repair may eventually be required.

2011-01-01

152

Percutaneous ultrasound-guided thrombin injection for the treatment of iatrogenic femoral artery pseudoaneurysms  

Energy Technology Data Exchange (ETDEWEB)

Purpose: To audit our experience with ultrasound-guided thrombin injection for the treatment of iatrogenic femoral artery pseudoaneurysms. Methods: A retrospective study of 85 consecutive patients undergoing percutaneous ultrasound-guided thrombin injection of post-catheterization femoral pseudoaneurysms during the period January 2002 to May 2007. Results: Pseudoaneurysms had a mean maximum diameter of 3.3 cm (range 1.0-7.6 cm) and a mean neck width of 3.4 mm (range 1.0-7.0 mm). No statistically significant correlation existed between maximum diameter and neck width (Kendall's rank correlation tau b = -0.09, p = 0.5). The median dose of thrombin injected was 425 U (range 100-1500 U). The procedure resulted in complete sac thrombosis in 81 (95%) patients. Seventy-nine pseudoaneurysms thrombosed immediately after one injection, whereas two required a second thrombin injection. There were no procedural complications. The maximum diameter of the pseudoaneurysm was predictive of procedural success (Wilcoxon's rank sum test, p = 0.001) and of the 5 patients with a pseudoaneurysm measuring {>=}6 cm, ultrasound-guided thrombin injection was unsuccessful in 4 (4/5 versus 0/80, p < 0.0001, Fisher's exact test). Three of these necessitated implantation of a stent-graft, whereas one required repeated thrombin injection and coil placement. In contrast, the pseudoaneurysm neck width did not seem to relate to the success of the procedure. Conclusion: Percutaneous ultrasound-guided thrombin injection of is a quick, effective and safe treatment for iatrogenic femoral pseudoaneurysms. For larger pseudoaneurysms, although it is worth attempting more than one thrombin injection, endovascular repair may eventually be required.

Vlachou, Paraskevi A. [Department of Radiology, Leicester Royal Infirmary, Leicester (United Kingdom); Karkos, Christos D., E-mail: ckarkos@hotmail.com [Department of Vascular and Endovascular Surgery, Leicester Royal Infirmary, Leicester (United Kingdom); Bains, Salena; McCarthy, Mark J. [Department of Vascular and Endovascular Surgery, Leicester Royal Infirmary, Leicester (United Kingdom); Fishwick, Guy; Bolia, Amman [Department of Radiology, Leicester Royal Infirmary, Leicester (United Kingdom)

2011-01-15

153

Percutaneous Repair of Radial Artery Pseudoaneurysm in a Hemodialysis Patient Using Sonographically Guided Thrombin Injection  

International Nuclear Information System (INIS)

We report a case of a radial artery pseudoaneurysm complicating an incorrect puncture of a Brescia-Cimino hemodialysis fistula that was treated with percutaneous ultrasound-guided thrombin injection. The pseudoaneurysm recurred after the initial successful thrombin injection. With a second injection we obtained permanent pseudoaneurysm occlusion. Our case illustrates that this procedure is an effective treatment in this type of arteriovenous fistula complication. We compare this case with the only similar one we could find in the literature

2006-02-01

154

Treatment of Iatrogenic Pseudoaneurysms Using Ultrasound-Guided Thrombin Injection over a 5-Year Period  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this study we demonstrate that ultrasound (US)-guided injection of thrombin is a safe and effective way to treat iatrogenic pseudoaneurysms as a new treatment modality at a 650-bed urban community hospital. We included retrospective chart review of patients who were treated for iatrogenic pseudoaneurysms from January 2004 to June 2010 at a single institution. All patients' pseudoaneurysms were treated using US-guided thrombin injection. This study demonstrated an overall success rate of 97...

2011-01-01

155

Obesity and thrombin-generation profiles in women with venous thromboembolism.  

Science.gov (United States)

Obesity is a known risk factor for venous and arterial thrombosis but the mechanisms are still unclear. In women, obesity is correlated with low-grade inflammation and recent data show that BMI is positively associated with thrombin generation. We explored the correlations between obesity, inflammation and thrombin generation in women with increased thrombotic risk by looking at a cohort of women with prior venous thrombosis. One hundred and fifty-six women age 18-65 years were enrolled at diagnosis of first venous thromboembolism (VTE). Plasma samples were obtained at least 3 weeks after cessation of anticoagulant treatment. Thrombin generation was determined with the calibrated automated thrombography (CAT) assay and the Innovance ETP assay. Thrombin generation started later but was more pronounced with higher endogenous thrombin generation potential (ETP) determined with CAT in patients with obesity. The Innovance ETP assay showed results consistent with CAT. Furthermore, patients with obesity had significantly higher levels of fibrinogen, C-reactive protein and plasminogen activator inhibitor-I (PAI-I) than patients without obesity. Increased levels of fibrinogen were the main determinant of the prolonged lag-time in patients with obesity whereas higher levels of prothrombin could account for the difference in the ETP between the groups. We found an association between BMI and ETP values using two different methods to measure thrombin generation. Obesity correlated with increased thrombin generation in women with VTE and the main determinants of this hypercoagulable state were increased levels of fibrinogen and prothrombin. This shows a possible link between obesity, low-grade inflammation and increased thrombin generation in women at increased risk for future thrombosis. PMID:23470648

Sonnevi, Kristina; Tchaikovski, Svetlana N; Holmström, Margareta; Antovic, Jovan P; Bremme, Katarina; Rosing, Jan; Lärfars, Gerd

2013-07-01

156

Brain Endothelial Cells Synthesize Neurotoxic Thrombin in Alzheimer’s Disease  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Alzheimer’s disease (AD) is characterized by neuronal death; thus, identifying neurotoxic proteins and their source is central to understanding and treating AD. The multifunctional protease thrombin is neurotoxic and found in AD senile plaques. The objective of this study was to determine whether brain endothelial cells can synthesize thrombin and thus be a source of this neurotoxin in AD brains. Microvessels were isolated from AD patient brains and from age-matched controls. Reverse transc...

Yin, Xiangling; Wright, Jill; Wall, Trevor; Grammas, Paula

2010-01-01

157

Development of a Multiplex Sandwich Aptamer Microarray for the Detection of VEGF165 and Thrombin  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this work we have developed a multiplex microarray system capable of detecting VEGF165 and thrombin. We recently described a Sandwich Aptamer Microarray (SAM) for thrombin detection feasible for use in multiplex microarrays; here we describe a new aptasensor for VEGF165 detection employing Vap7 and VEa5, two DNA aptamers recognizing different sites of the protein. The aptamers were modified to be adapted to the solid phase platform of SAM and their capability to simultaneously recognize VE...

Alice Sosic; Anna Meneghello; Agnese Antognoli; Erica Cretaio; Barbara Gatto

2013-01-01

158

Systems Biology of Coagulation Initiation: Kinetics of Thrombin Generation in Resting and Activated Human Blood  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Blood function defines bleeding and clotting risks and dictates approaches for clinical intervention. Independent of adding exogenous tissue factor (TF), human blood treated in vitro with corn trypsin inhibitor (CTI, to block Factor XIIa) will generate thrombin after an initiation time (Ti) of 1 to 2 hours (depending on donor), while activation of platelets with the GPVI-activator convulxin reduces Ti to ?20 minutes. Since current kinetic models fail to generate thrombin in the absence of a...

Chatterjee, Manash S.; Denney, William S.; Jing, Huiyan; Diamond, Scott L.

2010-01-01

159

Freshman Health Topics  

Science.gov (United States)

This article examines a cluster of health topics that are frequently selected by students in lower division classes. Topics address issues relating to addictive substances, including alcohol and tobacco, eating disorders, obesity, and dieting. Analysis of the topics examines their interrelationships and organization in the reference literature.…

Hovde, Karen

2011-01-01

160

Cancer Topic Searches  

Science.gov (United States)

Cancer Topic Searches are prepared literature searches of the National Library of Medicine's PubMed database. Literature citations on more than 100 different topics can be obtained. All citations on a specific topic can be retrieved, or the results can be limited by selecting one of three date ranges.

 
 
 
 
161

Pulsatile equibiaxial stretch inhibits thrombin-induced RhoA and NF-?B activation  

International Nuclear Information System (INIS)

This study investigated interactions between the effects of mechanical stretch and thrombin on RhoA activation in rat aortic smooth muscle cells (RASMC). Equibiaxial, pulsatile stretch, or thrombin produced a significant increase in RhoA activation. Surprisingly, in combination, 30 min of stretch inhibited the ability of thrombin to activate RhoA. NO donors and 8-bromo-cGMP significantly inhibited thrombin-induced RhoA activation. Interestingly, the nitric oxide synthase (NOS) inhibitor L-NAME increased basal RhoA activity, suggesting that NOS activity exerts a tonic inhibition on RhoA. Stretching RASMC increases nitrite production, consistent with the idea that NO contributes to the inhibitory effects of stretch. Thrombin stimulates MAP kinase and NF-?B pathways through Rho and these responses were blocked by 8-bromo-cGMP or stretch and restored by L-NAME. These data suggest that stretch, acting through NO and cGMP, can prevent the ability of thrombin to stimulate Rho signaling pathways that contribute to pathophysiological proliferative and inflammatory responses

2008-07-18

162

Use of fragments of hirudin to investigate thrombin-hirudin interaction.  

Science.gov (United States)

Site-directed mutagenesis was used to create hirudin in which Asn52 was replaced by methionine. Cyanogen bromide cleavage at this unique methionine resulted in two fragments. These fragments have been used to study the kinetic mechanism of the inhibition of thrombin by hirudin and to identify areas of the two molecules which interact with each other. The binding of the C-terminal fragment (residues 53-65) to thrombin resulted in a decrease in the Michaelis constant for the substrate D-phenylalanylpipecolylarginyl-p-nitroanilide (DPhe-Pip-Arg-NH-Ph). The N-terminal fragment (residues 1-52) was a competitive inhibitor of thrombin. There was a small amount of cooperativity in the binding of the two fragments. Whereas hirudin and its C-terminal fragment protected alpha-thrombin against cleavage by trypsin, the N-terminal fragment did not. Hirudin and the N-terminal fragment completely prevented the cleavage of alpha-thrombin by pancreatic elastase while the C-terminal fragment afforded a lesser degree of protection. The results of these experiments with trypsin and elastase are discussed in terms of interaction areas on thrombin and hirudin. PMID:2180697

Dennis, S; Wallace, A; Hofsteenge, J; Stone, S R

1990-02-22

163

Cleavage of prothrombin bound in immune complexes results in high thrombin enzymatic activity.  

Science.gov (United States)

Thrombin plays a pivotal role in blood clotting as well as in the regulation of vascular remodeling and oxidative stress. Recent evidence suggests that auto-antibodies directed against prothrombin, may play an important role in the pathogenesis of atherosclerosis. It is however not clear, if prothrombin bound in an immune complex retains its clotting and regulatory properties or acts solely by increasing vascular inflammation. In order to answer this question, we used a newly developed stain for the detection of thrombin activity of such complexes. Plasma and serum samples were subjected to rocket immunoelectrophoresis in an anti-prothrombin antiserum containing agarose gel. Gel plates, covered with a nitrocellulose membrane were soaked with chromogenic thrombin substrate. The product of thrombin activity was diazotized to red azo dye bound to nitrocellulose. Activity stain revealed barely discernible rockets in plasma, but heavily stained ones in serum. Pre-incubation with trypsin enhanced activity of immunoprecipitates deriving from plasma, but not from serum. Densitometric analysis showed, that the trypsin-enhanced activity in plasma derived immune complexes was twice as high as in serum derived immunoprecipitates. Thrombin active centre is not blocked by anti-prothrombin antiserum allowing to retain thrombin activity. Moreover, prothrombin in immunoprecipitate is readily cleaved by proteolytic enzymes. This cleavage could potentially be enhanced by antibody binding, although these results need to be confirmed using different antibodies. PMID:15213367

Pajdak, W; Radwan, J; Guzik, T J

2004-06-01

164

A label-free electrochemical aptasensor for sensitive thrombin detection in whole blood  

International Nuclear Information System (INIS)

In this paper, we reported a novel label-free electrochemical aptasensors for thrombin detection in whole blood using self-assembled multilayers with carboxymethyl-PEG-carboxymethyl (CM-PEG-CM) and thrombin-binding aptamer (TBA). In the sensing strategy, CM-PEG-CM and TBA were assembled on the electrode surface via covalent binding. In the presence of target, the TBA on the outermost layer of the self-assembled multilayer would catch the target on the electrode interface, which makes a barrier for electrons and inhibits the electro-transfer, resulting in the decreased DPV signals. Using this strategy, a wide detection range (1 pM–160 nM) for target thrombin was obtained, with a low detection limit of 1.56 × 10?14 M. The control experiments were also carried out by using bull serum albumin (BSA) and lysozyme in the absence of thrombin. The results showed that the aptasensors had good specificity, stability and reproducibility to thrombin. Moreover, the aptasensors could be used for detection of thrombin in whole blood which could provide a promising platform for fabrication of aptamer based biosensors in clinical application

2013-09-01

165

Presence of plasma proteins facilitates the uptake of 125I-thrombin by the rabbit thoracic aorta endothelium in vitro  

International Nuclear Information System (INIS)

Various purified proteins, protein derivatives and two polysaccharides were added individually to a physiological medium in order to effect uptake of 125I-thrombin by the rabbit aorta endothelium. Over a wide range of concentration (0.004-40 mg/ml), the presence of either purified rabbit or bovine albumin during thrombin uptake encouraged an increase (70-110%) in 125I-thrombin binding by the endothelium and subendothelium compared to uptake by aorta segments in the absence of added protein. Pretreatment of aorta segments with albumin before incubation with 125I-thrombin in the absence of albumin did not encourage thrombin uptake to the same extent as having 125I-thrombin and albumin together. Purified human transferrin, rabbit IgG, chicken ovalbumin or denatured bovine casein could replace albumin to produce a similar enhancement of thrombin uptake. Replacing active concentrations of albumin by either reduced-carboxymethylated albumin, defatted albumin, plasmin-treated or thermolysin-treated albumin also caused an increase (50-130%) in thrombin binding, whereas replacement by acid-hydrolysed albumin or with polyglutamic acid was either ineffective or even inhibitory. Lysine-modified or arginine-modified albumins caused a small enhancement (14-32%) and no enhancement of thrombin uptake, respectively. Dextran, at low concentration (0.04-0.4 mg/ml) did not influence thrombin uptake, and at higher concentration (4-40 mg/ml) caused a decrease in uptake by both the endothelium and subendothelial layers. Low concentration of dextran sulphate inhibited thrombin uptake to 20-30% of control values. These data express the importance of accompanying protein in the response of the vascular endothelium during binding of thrombin. The possibility that other protein-cell interactions may be similarly influenced by macromolecular solutes is also discussed

1986-07-01

166

Design, synthesis and evaluation of graftable thrombin inhibitors for the preparation of blood-compatible polymer materials.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Piperazinyl-amide derivatives of N-alpha-(3-trifluoromethyl-benzenesulfonyl)-L-arginine (1) were synthesized as graftable thrombin inhibitors. The possible disturbance of biological activity due to a variable spacer-arm fixed on the N-4 piperazinyl position was evaluated in vitro, against human alpha-thrombin, and in blood coagulation assay. Molecular modelling (in silico analysis) and X-ray diffraction studies of thrombin-inhibitor complexes were also performed. The fixation of bioactive mol...

Salvagnini, Claudio; Michaux, Catherine; Remiche, Julie; Wouters, Johan; Charlier, Paulette; Marchand-brynaert, Jacqueline

2005-01-01

167

Effects of tissue factor, thrombomodulin and elevated clotting factor levels on thrombin generation in the calibrated automated thrombogram  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Elevated procoagulant levels have been correlated with increased thrombin generation in vitro and with increased venous thromboembolism (VTE) risk in epidemiological studies. Thrombin generation tests are increasingly being employed as a high throughput method to provide a global measure of procoagulant activity in plasma samples. The objective of this study was to distinguish the effects of assay conditions [tissue factor (TF), thrombomodulin, platelets/lipids] and factor levels on thrombin ...

Machlus, Kellie R.; Colby, Emily A.; Wu, Jogin R.; Koch, Gary G.; Key, Nigel S.; Wolberg, Alisa S.

2009-01-01

168

Thrombin Injection for Treatment of Brachial Artery Pseudoaneurysm at the Site of a Hemodialysis Fistula: Report of Two Patients  

International Nuclear Information System (INIS)

We report two patients with arteriovenous hemodialysis fistulas that were complicated by brachial artery pseudoaneurysms. Each pseudoanerysm was percutaneously thrombosed with an injection of thrombin, using techniques to prevent escape of thrombin into the native brachial artery. In one patient, an angioplasty balloon was inflated across the neck of the aneurysm during thrombin injection. In the second patient, thrombin was injected during ultrasound-guided compression of the neck of the pseudoaneurysm. Complete thrombosis of each pseudoaneurysm was achieved within 30 sec. No ischemic or embolic events occurred. This technique may be useful in treating pseudoaneurysms of smaller peripheral arteries

2000-09-01

169

A blood meal-induced Ixodes scapularis tick saliva serpin inhibits trypsin and thrombin, and interferes with platelet aggregation and blood clotting.  

Science.gov (United States)

Ixodes scapularis is a medically important tick species that transmits causative agents of important human tick-borne diseases including borreliosis, anaplasmosis and babesiosis. An understanding of how this tick feeds is needed prior to the development of novel methods to protect the human population against tick-borne disease infections. This study characterizes a blood meal-induced I. scapularis (Ixsc) tick saliva serine protease inhibitor (serpin (S)), in-house referred to as IxscS-1E1. The hypothesis that ticks use serpins to evade the host's defense response to tick feeding is based on the assumption that tick serpins inhibit functions of protease mediators of the host's anti-tick defense response. Thus, it is significant that consistent with hallmark characteristics of inhibitory serpins, Pichia pastoris-expressed recombinant IxscS-1E1 (rIxscS-1E1) can trap thrombin and trypsin in SDS- and heat-stable complexes, and reduce the activity of the two proteases in a dose-responsive manner. Additionally, rIxscS-1E1 also inhibited, but did not apparently form detectable complexes with, cathepsin G and factor Xa. Our data also show that rIxscS-1E1 may not inhibit chymotrypsin, kallikrein, chymase, plasmin, elastase and papain even at a much higher rIxscS-1E1 concentration. Native IxscS-1E1 potentially plays a role(s) in facilitating I. scapularis tick evasion of the host's hemostatic defense as revealed by the ability of rIxscS-1E1 to inhibit adenosine diphosphate- and thrombin-activated platelet aggregation, and delay activated partial prothrombin time and thrombin time plasma clotting in a dose-responsive manner. We conclude that native IxscS-1E1 is part of the tick saliva protein complex that mediates its anti-hemostatic, and potentially inflammatory, functions by inhibiting the actions of thrombin, trypsin and other yet unknown trypsin-like proteases at the tick-host interface. PMID:24583183

Ibelli, Adriana M G; Kim, Tae K; Hill, Creston C; Lewis, Lauren A; Bakshi, Mariam; Miller, Stephanie; Porter, Lindsay; Mulenga, Albert

2014-05-01

170

Lipopolysaccharide interactions of C-terminal peptides from human thrombin.  

Science.gov (United States)

Interactions with bacterial lipopolysaccharide (LPS), both in aqueous solution and in lipid membranes, were investigated for a series of amphiphilic peptides derived from the C-terminal region of human thrombin, using ellipsometry, dual polarization interferometry, fluorescence spectroscopy, circular dichroism (CD), dynamic light scattering, and z-potential measurements. The ability of these peptides to block endotoxic effects caused by LPS, monitored through NO production in macrophages, was compared to peptide binding to LPS and its endotoxic component lipid A, and to size, charge, and secondary structure of peptide/LPS complexes. While the antiendotoxic peptide GKY25 (GKYGFYTHVFRLKKWIQKVIDQFGE) displayed significant binding to both LPS and lipid A, so did two control peptides with either selected D-amino acid substitutions or with maintained composition but scrambled sequence, both displaying strongly attenuated antiendotoxic effects. Hence, the extent of LPS or lipid A binding is not the sole discriminant for the antiendotoxic effect of these peptides. In contrast, helix formation in peptide/LPS complexes correlates to the antiendotoxic effect of these peptides and is potentially linked to this functionality. Preferential binding to LPS over lipid membrane was furthermore demonstrated for these peptides and preferential binding to the lipid A moiety within LPS inferred. PMID:23537377

Singh, Shalini; Kalle, Martina; Papareddy, Praveen; Schmidtchen, Artur; Malmsten, Martin

2013-05-13

171

Purification and Characterization of Human Thrombin Activatable Fibrinolysis Inhibitor (TAFI)  

DEFF Research Database (Denmark)

Thrombin Activatable Fibrinolysis inhibitor (TAFI) is a basic carboxypeptidase, circulating in plasma as an enzymatic inactive precursor. TAFI shares ~40% overall sequence identity with pancreas Carboxypeptidase B (PCPB) with the activation peptide being less conserved. Following activation of TAFI we observed a change in the isoelectric point (IP) of TAFIa. The IP of TAFIa was significantly more basic than the IP of TAFI. This was not observed in PCPB. Due to the change in IP, we have investigated the structural basis for this observation by mapping the N- and O-linked glycans. TAFI has 5 potential N-linked glycosylation sites, four of them located on the activation peptide. Only one potential O-linked glycosylation site is seen. In addition, TAFIa is unstable and loose enzymatic activity quickly. This is in contrast to the homologous PCPB. The structural basis for this observation is not known but could be caused by differences in thermodynamic stability. Disulfides are a major contributor to the structuralintegrity of proteins and disulfide permutations could explain the difference in enzymatic stability. To test this hypothesis we have identified the disulfide pattern of the eight cysteines in TAFI. In this study we have purified and characterized TAFI from human plasma.

Christensen, Trine; Skottrup, Peter Durand

172

Adenosine regulates the proinflammatory signaling function of thrombin in endothelial cells.  

Science.gov (United States)

The plasma level of the regulatory metabolite adenosine increases during the activation of coagulation and inflammation. Here we investigated the effect of adenosine on modulation of thrombin-mediated proinflammatory responses in HUVECs. We found that adenosine inhibits the barrier-disruptive effect of thrombin in HUVECs by a concentration-dependent manner. Analysis of cell surface expression of adenosine receptors revealed that A2A and A2B are expressed at the highest level among the four receptor subtypes (A2B ?>?A2A ?>?A1 ?>?A3 ) on HUVECs. The barrier-protective effect of adenosine in response to thrombin was recapitulated by the A2A specific agonist, CGS 21680, and abrogated both by the siRNA knockdown of the A2A receptor and by the A2A -specific antagonists, ZM-241385 and SCH-58261. The thrombin-induced RhoA activation and its membrane translocation were both inhibited by adenosine in a cAMP-dependent manner, providing a molecular mechanism through which adenosine exerts a barrier-protective function. Adenosine also inhibited thrombin-mediated activation of NF-?B and decreased adhesion of monocytic THP-1 cells to stimulated HUVECs via down-regulation of expression of cell surface adhesion molecules, VCAM-1, ICAM-1, and E-selectin. Moreover, adenosine inhibited thrombin-induced elevated expression of proinflammatory cytokines, IL-6 and HMGB-1; and chemokines, MCP-1, CXCL-1, and CXCL-3. Taken together, these results suggest that adenosine may inhibit thrombin-mediated proinflammatory signaling responses, thereby protecting the endothelium from injury during activation of coagulation and inflammation. J. Cell. Physiol. 229: 1292-1300, 2014. © 2014 Wiley Periodicals, Inc. PMID:24477600

Hassanian, Seyed Mahdi; Dinarvand, Peyman; Rezaie, Alireza R

2014-09-01

173

Design and characterization of hirulogs: A novel class of bivalent peptide inhibitors of thrombin  

International Nuclear Information System (INIS)

A novel class of synthetic peptides has been designed that inhibit the thrombin catalytic site and exhibit specificity for the anion-binding exosite (ABE) of ?-thrombin. These peptides, called hirulogs, consist of (i) an active-site specificity sequence with a restricted Arg-Pro scissile bond, (ii) a polymeric linker of glycyl residues from 6 to 18 angstrom in length, and (iii) an ABE recognition sequence such as that in the hirudin C-terminus. Hirulog-1 [(D-Phe)-Pro-Arg-Pro-(Gly)4-Asn-Gly-Asp-Phe-Glu-Glu-Ile-Pro-Glu-Tyr-Leu] inhibits the thrombin-catalyzed hydrolysis of a tripeptide p-nitroanilide substrate with Ki = 2.3 nM. In contrast, the synthetic C-terminal hirudin peptide S-Hir53-64, which binds to the thrombin ABE, blocked the fibrinogen clotting activity of the enzyme with Ki = 144 nM but failed to inhibit the hydrolysis of p-nitroanilide substrates at concentrations as high as 1 mM. Hirulog-1, but not S-Hir53-64, was found to inhibit the incorporation of [14C]diisopropyl fluorophosphate in thrombin. Hirulog-1 appears specific for thrombin as it lacks inhibitory activities toward human factor Xa, human plasmin, and bovine trypsin at inhibitor:enzyme concentrations 3 orders of magnitude higher than those required to inhibit thrombin. The optimal inhibitory activity of hirulog-1 depends upon all three components of its structure. Comparison of anticoagulant activities of hirulog-1, hirudin, and S-Hir53-64 showed that the synthetic hirulog-1 is 2-fold more potent than hirudin and 100-fold more active than S-Hir53-64 in increasing the activated partial thromboplastin time of normal human plasma

1990-07-31

174

Studies of thrombin-induced proteoglycan release in the degradation of human and bovine cartilage.  

Science.gov (United States)

Because fibrin is commonly observed within arthritic joints, studies were undertaken to determine whether purified coagulation and fibrinolytic proteases degrade cartilage in vitro and to seek evidence for the activation of coagulation in arthritic joints through measurements of the levels of inhibitor-enzyme complexes and several other proteins associated with coagulation and fibrinolysis. The concentrations of 13 plasma proteins and complexes of thrombin and Factor Xa with antithrombin III were measured in synovial fluids recovered at the time of knee replacement surgery. All zymogens necessary to constitute the coagulation cascade were present. Thrombin and the combination of prothrombin plus prothrombinase induced proteoglycan release from both normal and arthritic cartilages. Factor Xa and plasmin induced release from diseased cartilage only, and urokinase, tissue plasminogen activator, and activated protein C were without effect at the levels used. At saturating levels of thrombin (> or = 2.0 microM) 80% of the proteoglycan content of normal cartilage was released within 24 h. Thrombin, which is cationic, reversibly binds cartilage with Kd = 7.0 +/- 1.0 microM and Bmax = 820 +/- 70 ng/mg of human cartilage. Levels of thrombin-antithrombin III complexes in synovial fluids and arthritis were 4-fold higher in osteo (OA) and 43-fold higher in rheumatoid (RA) than in controls (0.98 nM). Factor Xa-antithrombin III complex levels were threefold lower in OA and fivefold higher in RA than in controls (0.24 nM). These elevated levels of enzyme-inhibitor complexes imply a history of activation of coagulation within the joint, especially in RA. Since thrombin degrades cartilage in vitro and had been generated in vivo, as inferred by the existence of thrombin-antithrombin III complexes, intraarticular activation of coagulation may both contribute to the pathology of arthritis and comprise a target for therapy and diagnosis.

Furmaniak-Kazmierczak, E; Cooke, T D; Manuel, R; Scudamore, A; Hoogendorn, H; Giles, A R; Nesheim, M

1994-01-01

175

Intraovarian thrombin and activated protein C signaling system regulates steroidogenesis during the periovulatory period.  

Science.gov (United States)

In addition to its role in blood coagulation, thrombin directly stimulates protease-activated receptors (PAR) or interacts with thrombomodulin (THBD) to activate membrane-bound protein C which stimulates PAR1 and PAR4 receptors to promote downstream pleiotropic effects. Our DNA microarray, RT-PCR, and immunostaining analyses demonstrated ovarian expression of THBD, activated protein C (APC) receptor [endothelial protein C receptor (EPCR)], as well as PAR1 and PAR4 receptors in mice. After treatment of gonadotropin-primed immature mice with an ovulatory dose of human chorionic gonadotropin (hCG) (a LH surrogate), major increases in the expression of THBD, EPCR, PAR1, and PAR4 were detected in granulosa and cumulus cells of preovulatory follicles. Immunoassay analyses demonstrated sustained increases in ovarian prothrombin and APC levels after hCG stimulation. We obtained luteinizing granulosa cells from mice treated sequentially with equine CG and hCG. Treatment of these cells with thrombin or agonists for PAR1 or PAR4 decreased basal and forskolin-induced cAMP biosynthesis and suppressed hCG-stimulated progesterone production. In cultured preovulatory follicles, treatment with hirudin (a thrombin antagonist) and SCH79797 (a PAR1 antagonist) augmented hCG-stimulated progesterone biosynthesis, suggesting a suppressive role of endogenous thrombin in steroidogenesis. Furthermore, intrabursal injection with hirudin or SCH79797 led to ipsilateral increases in ovarian progesterone content. Our findings demonstrated increased ovarian expression of key components of the thrombin-APC-PAR1/4 signaling system after LH/hCG stimulation, and this signaling pathway may allow optimal luteinization of preovulatory follicles. In addition to assessing the role of thrombin and associated genes in progesterone production by the periovulatory ovary, these findings provide a model with which to study molecular mechanisms underlying thrombin-APC-PAR1/4 signaling. PMID:22207716

Cheng, Yuan; Kawamura, Kazuhiro; Deguchi, Masashi; Takae, Seido; Mulders, Sabine M; Hsueh, Aaron J W

2012-02-01

176

Topical report review status  

International Nuclear Information System (INIS)

A Topical Report Review Status is scheduled to be published semi-annually. The primary purpose of this document is to provide periodic progress reports of on-going topical report reviews, to identify those topical reports for which the Nuclear Regulatory Commission (NRC) staff review has been completed and, to the extent practicable, to provide NRC management with sufficient information regarding the conduct of the topical report program to permit taking whatever actions deemed necessary or appropriate. This document is also intended to be a source of information to NRC Licensing Project Managers and other NRC personnel regarding the status of topical reports which may be referenced in applications for which they have responsibility. This status report is published primarily for internal NRC use in managing the topical report program, but is also used by NRC to advise the industry of report review status

1983-01-01

177

Topical report review status  

International Nuclear Information System (INIS)

A Topical Report Review Status is scheduled to be published semi-annually. The primary purpose of this document is to provide periodic progress reports of on-going topical report reviews, to identify those topical reports for which the Nuclear Regulatory Commission (NRC) staff review has been completed and, to the extent practicable, to provide NRC management with sufficient information regarding the conduct of the topical report program to permit taking whatever actions deemed necessary or appropriate. This document is also intended to be a source of information to NRC Licensing Project Managers and other NRC personnel regarding the status of topical reports which may be referenced in applications for which they have responsibility. This status report is published primarily for internal NRC use in managing the topical report program, but is also used by NRC to advise the industry of report review status

1982-01-01

178

Myocardial Topical Negative Pressure  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this research was to find out if it is possible to increase myocardial microvasular blood flow by applying a topical negative pressure source directly onto the myocardium. Topical negative pressure is a relatively new wound healing technique. When used in wound therapy, topical negative pressure has been shown to increase microvascular blood flow, to stimulate granulation tissue formation, and to stimulate angiogenesis in the underlying tissue, mainly subcutaneous tissue and skele...

Lindstedt, Sandra

2008-01-01

179

TOPICAL TREATMENT OF MELASMA  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Melasma is a common hypermelanotic disorder affecting the face that is associated with considerable psychological impacts. The management of melasma is challenging and requires a long-term treatment plan. In addition to avoidance of aggravating factors like oral pills and ultraviolet exposure, topical therapy has remained the mainstay of treatment. Multiple options for topical treatment are available, of which hydroquinone (HQ) is the most commonly prescribed agent. Besides HQ, other topical ...

Bandyopadhyay Debabrata

2009-01-01

180

Substitution of valine for glycine-558 in the congenital dysthrombin thrombin Quick II alters primary substrate specificity  

Energy Technology Data Exchange (ETDEWEB)

Thrombin Quick II is one of two dysfunctional forms of thrombin derived from the previously described congenital dysprothrombin prothrombin Quick. Thrombin Quick II does not clot fibrinogen, hydrolyze p-nitroanilide substrates of thrombin, or bind N{sup 2}-(5-(dimethylamino)naphthalene-1-sulfonyl)arginine N,N-(3-ethyl-1,5-pentanediyl)amide, a high-affinity competitive inhibitor of thrombin. To determine the structural alteration in thrombin Quick II, the reduced, carboxymethylated protein was hydrolyzed by a lysyl endopeptidase. A peptide not present in a parallel thrombin hydrolysate was identified by reverse-phase chromatography. This Gly residue, which is highly conserved in the chymotrypsin family of serine proteases, forms part of the substrate binding pocket for bulky aromatic and basic side chains in chymotrypsin and trypsin, respectively. However, in porcine elastase 1, the corresponding residue is threonine. Consistent with the identified structural alteration, thrombin Quick II incorporates ({sup 3}H)diisopropyl fluorophosphate stoichiometrically and hydrolyzes the elastase substrate succinyl-Ala-Ala-Pro-Leu-p-nitroanilide with a relative k{sub cat}/K{sub M} of 0.14 when compared to thrombin. This results from a 3-fold increase in K{sub M} and a 2.5-fold decrease in k{sub cat} for thrombin Quick II when compared to thrombin acting on the same substrate. These results and those of other investigators studying mutant trypsins support the conclusion that the catalytic activity of serine proteases is very sensitive to structural alterations in the primary substrate binding pocket.

Henriksen, R.A.; Mann, K.G. (Univ. of Vermont, Burlington (USA))

1989-03-07

 
 
 
 
181

Thrombin generation in Cushing's Syndrome: do the conventional clotting indices tell the whole truth?  

Science.gov (United States)

Cushing's Syndrome (CS) is associated with an increased mortality, where hypercoagulability seems to have a crucial role in both arterial and venous thrombosis. Parameters of in vitro thrombin generation (TG) such as lag time, peak thrombin and endogenous thrombin potential (ETP), that describe the time until thrombin burst, the peak amount of TG and the total amount of thrombin generated, respectively as well as classical clotting markers were evaluated in 33 CS patients compared to both a group of 28 patients matched for the features of Metabolic Syndrome (MetS) and 31 healthy individuals. CS and MetS patients had shorter lag time (p ETP (p ETP (r = + 0.34; p = 0.001, r = + 0.28; p = 0.008, respectively). Obese and diabetic patients had shorter lag time (p = 0.0005; p = 0.0002, respectively), higher ETP (p = 0.0006; p = 0.007, respectively) and peak (p = 0.0003; p = 0.0005, respectively) as well as a more prolonged PT (p = 0.04; p = 0.009, respectively). Hypertensive individuals had higher ETP (p = 0.004), peak (p = 0.0008) and FVIII (p = 0.001). Our findings confirm a prothrombotic state in both CS and MetS patients, though lag time was less shortened in CS. The high levels of endogenous physiological anticoagulants, could possibly represent a protective mechanism against hypercoagulability seen in CS patients. PMID:23408210

Koutroumpi, S; Spiezia, L; Albiger, N; Barbot, M; Bon, M; Maggiolo, S; Gavasso, S; Simioni, P; Frigo, A; Mantero, F; Scaroni, C

2014-02-01

182

Ethanol interferes with thrombin mediated changes in the morphology and cytoskeleton of human vascular endothelial cells  

Energy Technology Data Exchange (ETDEWEB)

The effect of physiological concentrations of ethanol (EtOH) on the response of human vascular endothelial cells (EC) to thrombin was examined Treatment of EC with EtOH concentrations of 20-85mM for 2-10 min. produced no significant changes in the morphology of 3- and 4-day monolayers established on fibronectin coated polystyrene. When examined immunofluorescently no significantly changes in the microfilament or microtubule structures were seen. Exposure of EC monolayers to 0.5 and 1 U/ml of thrombin for 1-60 minutes causes a concentration and time dependent monolayer retraction, evidenced by a general decrease in cell size, increase in visible gaps in the monolayer and redistribution of the microtubule and microfilament networks. Pretreatment of EC monolayers with EtOH for 3-5 minutes prior to addition of thrombin prevents the changes seen with thrombin alone. Immunofluorescent examination of the microfilament and microtubule structures suggests than EtOH may act in part via the microtubule network, which appears to be disorganized/disrupted when the EC are exposed to EtOH and then thrombin. Colchicine studies show that EC which have been pretreated with EtOH respond to colchicine differently then cells which have not previously seen EtOH. These data suggest that EtOH may alter EC monolayer responsiveness either by indirect changes which are reflected in cytoskeletal disorganization or possibly by direct influence on the cytoskeleton.

Pratt, K.J.; Rubin, R.; Hoek, J.; Williams, S.K. (Thomas Jefferson Univ., Philadelphia, PA (United States))

1991-03-15

183

Thrombin hydrolysis of an N-terminal peptide from fibrinogen Lille: kinetic and NMR studies.  

Science.gov (United States)

Fibrinogen Lille, a congenital dysfibrinogenemia, has been reported to arise from a mutation from Asp to Asn at position 7 of the A alpha chain of human fibrinogen, thereby reducing the thrombin-catalyzed rate of hydrolysis of the Arg(16)-Gly(17) peptide bond of this chain. Synthetic peptides of relevant portions of the wild-type and mutant A alpha chains were prepared, and the thrombin-catalyzed rates of hydrolysis of their Arg(16)-Gly(17) peptide bonds were determined. In addition, transferred NOE measurements were made to deduce their conformations, when complexed to bovine thrombin. The kinetics data showed little difference in the hydrolysis rates between the wild-type and mutant peptides, and the NMR data indicate no difference in the bound conformation of these two peptides. Therefore, electrostatic (or salt-bridge) interactions between Asp(7) and thrombin do not influence the bound conformations of these peptides. Asp(7) may interact with a remote residue of fibrinogen, not present in these synthetic peptides, or there may be additional mutations beyond A alpha (1-20) which have not been detected in fibrinogen Lille. Alternatively, when thrombin binds to fibrinogen at its secondary binding site, its primary (active) site may display different reactivities toward wild-type fibrinogen and fibrinogen Lille. PMID:1581297

Zheng, Z; Ashton, R W; Ni, F; Scheraga, H A

1992-05-12

184

Choosing a Research Topic  

Science.gov (United States)

This website from the Chronicle of Higher Education features tips for graduate students on choosing a research topic. The author explains a variety of ways that a topic should be matched to the individual. A good choice can help lead to long-term career success.

Reis, Richard M.; Education, The C.

185

Mapping topics and topic bursts in PNAS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Scientific research is highly dynamic. New areas of science continually evolve; others gain or lose importance, merge, or split. Due to the steady increase in the number of scientific publications, it is hard to keep an overview of the structure and dynamic development of one's own field of science, much less all scientific domains. However, knowledge of “hot” topics, emergent research frontiers, or change of focus in certain areas is a critical component of resource allocation decisions ...

2004-01-01

186

Implicit stage topics  

Directory of Open Access Journals (Sweden)

Full Text Available Il a souvent été proposé que les éléments spatio-temporels en position initiale de phrase spécifient le cadre de l’événement dénoté par la proposition et ont une interprétation thématique ou topicale. Alors que les topiques spatio-temporels explicites ont souvent été étudiés, Erteschik-Schir (1997, 1999 propose l’idée que les topiques spatio-temporels, ou topiques scéniques (stage topics peuvent aussi être implicites.Dans cet article, nous offrons des arguments en faveur de la notion de topique scénique implicite. Nous montrons qu’un certain nombre de cas d’inversion nominale en français, une configuration syntaxique qui est favorisée par la présence d’un topique scénique explicite, s’expliquent par la présence d’un topique scénique implicite. Le fait que les topiques scéniques implicites interagissent avec la structure syntaxique de la même façon que les topiques scéniques explicites constitue un argument empirique en faveur de leur existence.It has often been proposed that sentence-initial spatio-temporal elements specify the frame in which the whole proposition takes place and are topical (i.e. thematic. Whereas considerable attention has been paid to explicit spatio-temporal topics, Erteschik-Shir (1997, 1999 argues that spatio-temporal topics, or stage topics, can also be implicit.In this article we provide evidence in favour of the notion of implicit stage topic. We show that a certain number of nominal inversion cases in French, a syntactic configuration which is triggered by the presence of an explicit stage topic, are explained by the presence of an implicit stage topic. The fact that implicit stage topics interact with syntactic structure the same way explicit stage topics do constitutes a strong empirical argument in favour of their existence.

Karen Lahousse

2008-04-01

187

Thrombin-induced Migration and Matrix Metalloproteinase-9 Expression Are Regulated by MAPK and PI3K Pathways in C6 Glioma Cells  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Glioblastoma multiforme is one of the most common and aggressive tumors in central nervous system. It often possesses characteristic necrotic lesions with hemorrhages, which increase the chances of exposure to thrombin. Thrombin has been known as a regulator of MMP-9 expression and cancer cell migration. However, the effects of thrombin on glioma cells have not been clearly understood. In the present study, influences of thrombin on glioma cell migration were examined using Boyden chamber mig...

Kim, Jiyoung; Lee, Jae-won; Kim, Song-in; Choi, Yong-joon; Lee, Won-ki; Jeong, Myung-ja; Cha, Sang-hoon; Lee, Hee Jae; Chun, Wanjoo; Kim, Sung-soo

2011-01-01

188

Bivalirudin is a Dual Inhibitor of Thrombin and Collagen-Dependent Platelet Activation in Patients Undergoing Percutaneous Coronary Intervention  

Science.gov (United States)

Background Bivalirudin, a direct thrombin inhibitor, is a widely used adjunctive therapy in patients undergoing percutaneous intervention (PCI). Thrombin is a highly potent agonist of platelets and activates the protease-activated receptors, PAR1 and PAR4, but it is not known whether bivalirudin exerts anti-platelet effects in PCI patients. We tested the hypothesis that bivalirudin acts as an anti-platelet agent in PCI patients by preventing activation of PARs on the platelet surface. Methods and Results The effect of bivalirudin on platelet function and systemic thrombin levels was assessed in patients undergoing elective PCI. Mean plasma levels of bivalirudin were 2.7 ± 0.5 ?M during PCI which correlated with marked inhibition of thrombin-induced platelet aggregation and significantly inhibited cleavage of PAR1. Unexpectedly, bivalirudin also significantly inhibited collagen-platelet aggregation during PCI. Collagen induced a conversion of the platelet surface to a procoagulant state in a thrombin-dependent manner which was blocked by bivalirudin. Consistent with this result, bivalirudin reduced systemic thrombin levels by more than 50% during PCI. Termination of the bivalirudin infusion resulted in rapid clearance of the drug with a half-life of 29.3 minutes. Conclusions Bivalirudin effectively suppresses thrombin-dependent platelet activation via inhibition of PAR1 cleavage and inhibits collagen-induced platelet procoagulant activity as well as systemic thrombin levels in patients undergoing PCI.

Kimmelstiel, Carey; Zhang, Ping; Kapur, Navin K.; Weintraub, Andrew; Krishnamurthy, Barath; Castaneda, Vilma; Covic, Lidija; Kuliopulos, Athan

2011-01-01

189

Comparison of the 'Chemical' and 'Structural' Approaches to the Optimization of the Thrombin-Binding Aptamer  

Science.gov (United States)

Noncanonically structured DNA aptamers to thrombin were examined. Two different approaches were used to improve stability, binding affinity and biological activity of a known thrombin-binding aptamer. These approaches are chemical modification and the addition of a duplex module to the aptamer core structure. Several chemically modified aptamers and the duplex-bearing ones were all studied under the same conditions by a set of widely known and some relatively new methods. A number of the thrombin-binding aptamer analogs have demonstrated improved characteristics. Most importantly, the study allowed us to compare directly the two approaches to aptamer optimization and to analyze their relative advantages and disadvantages as well as their potential in drug design and fundamental studies.

Tatarinova, Olga; Tsvetkov, Vladimir; Basmanov, Dmitry; Barinov, Nikolay; Smirnov, Igor; Timofeev, Edward; Kaluzhny, Dmitry; Chuvilin, Andrey; Klinov, Dmitry; Varizhuk, Anna; Pozmogova, Galina

2014-01-01

190

An Integrated Mathematical Model of Thrombin-, Histamine-and VEGF-Mediated Signalling in Endothelial Permeability  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Endothelial permeability is involved in injury, inflammation, diabetes and cancer. It is partly regulated by the thrombin-, histamine-, and VEGF-mediated myosin-light-chain (MLC activation pathways. While these pathways have been investigated, questions such as temporal effects and the dynamics of multi-mediator regulation remain to be fully studied. Mathematical modeling of these pathways facilitates such studies. Based on the published ordinary differential equation models of the pathway components, we developed an integrated model of thrombin-, histamine-, and VEGF-mediated MLC activation pathways. Results Our model was validated against experimental data for calcium release and thrombin-, histamine-, and VEGF-mediated MLC activation. The simulated effects of PAR-1, Rho GTPase, ROCK, VEGF and VEGFR2 over-expression on MLC activation, and the collective modulation by thrombin and histamine are consistent with experimental findings. Our model was used to predict enhanced MLC activation by CPI-17 over-expression and by synergistic action of thrombin and VEGF at low mediator levels. These may have impact in endothelial permeability and metastasis in cancer patients with blood coagulation. Conclusion Our model was validated against a number of experimental findings and the observed synergistic effects of low concentrations of thrombin and histamine in mediating the activation of MLC. It can be used to predict the effects of altered pathway components, collective actions of multiple mediators and the potential impact to various diseases. Similar to the published models of other pathways, our model can potentially be used to identify important disease genes through sensitivity analysis of signalling components.

Tan CY

2011-07-01

191

Influence of single nucleotide polymorphisms on thrombin generation in factor V Leiden heterozygotes.  

Science.gov (United States)

Carriership of the factor V (FV) Leiden mutation increases the risk of venous thromboembolism (VTE) ~4-fold, but the individual risk of each FV Leiden carrier depends on several co-inherited risk and protective factors. Under the hypothesis that thrombin generation might serve as an intermediate phenotype to identify genetic modulators of VTE risk, we enrolled 188 FV Leiden heterozygotes (11 with VTE) and determined the following parameters: thrombin generation in the absence and presence of activated protein C (APC); plasma levels of prothrombin, factor X, antithrombin, protein S and tissue factor pathway inhibitor; and the genotypes of 24 SNPs located in the genes encoding these coagulation factors and inhibitors. Multiple regression analysis was subsequently applied to identify the (genetic) determinants of thrombin generation. The endogenous thrombin potential (ETP) showed a striking inter-individual variability among different FV Leiden carriers and, especially when measured in the presence of APC, correlated with VTE risk. Several SNPs in the F2 (rs1799963, rs3136516), F10 (rs693335), SERPINC1 (rs2227589), PROS1 (Heerlen polymorphism) and TFPI (rs5940) genes significantly affected the ETP-APC and/or the ETP+APC in FV Leiden carriers. Most of these SNPs have shown an association with VTE risk in conventional epidemiological studies, suggesting that the genetic dissection of thrombin generation leads to the detection of clinically relevant SNPs. In conclusion, we have identified several SNPs that modulate thrombin generation in FV Leiden heterozygotes. These SNPs may help explain the large variability in VTE risk observed among different FV Leiden carriers. PMID:24226152

Segers, O; Simioni, P; Tormene, D; Castoldi, E

2014-03-01

192

Ligand Binding to Anion-binding Exosites Regulates Conformational Properties of Thrombin*  

Science.gov (United States)

Thrombin participates in coagulation, anticoagulation, and initiation of platelet activation. To fulfill its diverse roles and maintain hemostasis, this serine protease is regulated via the extended active site region and anion-binding exosites (ABEs) I and II. For the current project, amide proton hydrogen-deuterium exchange coupled with MALDI-TOF mass spectrometry was used to characterize ligand binding to individual exosites and to investigate the presence of exosite-active site and exosite-exosite interactions. PAR3(44–56) and PAR1(49–62) were observed to bind to thrombin ABE I and then to exhibit long range effects over to ABE II. By contrast, Hirudin(54–65) focused more on ABE I and did not transmit influences over to ABE II. Although these three ligands were each directed to ABE I, they did not promote the same conformational consequences. d-Phe-Pro-Arg-chloromethyl ketone inhibition at the thrombin active site led to further local and long range consequences to thrombin-ABE I ligand complexes with the autolysis loop often most affected. When Hirudin(54–65) was bound to ABE I, it was still possible to bind GpIb?(269–286) or fibrinogen ??(410–427) to ABE II. Each ligand exerted its predominant influences on thrombin and also allowed interexosite communication. The results obtained support the proposal that thrombin is a highly dynamic protein. The transmission of ligand-specific local and long range conformational events is proposed to help regulate this multifunctional enzyme.

Malovichko, Marina V.; Sabo, T. Michael; Maurer, Muriel C.

2013-01-01

193

The technique of measuring thrombin generation with fluorogenic substrates: 1. Necessity of adequate calibration.  

Science.gov (United States)

In fluorogenic thrombin generation (TG) measurement the concentrations of thrombin are obtained from the course of fluorescence intensity. Because of fluorescence quenching, in one series of normal plasmas (n = 60), the rate of fluorescence increase at fixed thrombin activity was 70 +/- 13% of that in buffer, in another (n = 139) 75 +/- 8%. Using a calibration factor (CF) measured in buffer therefore underestimates thrombin concentrations in plasma and introduces a source of error. A fixed CF also neglects the 25-35% increase of CF during the experiment and thus distorts the form of the TG curve so that the ETP cannot be determined. Continuous individual calibration (CIC), in which CF is determined continuously in a parallel sample, avoids such systematic errors but adds random error because the thrombin course is calculated from two different measurements. We determined the intra-individual coefficients of variation (CV) of the peak-height and ETP as obtained with CIC to those obtained with a fixed CF measured in buffer. With the fixed CF, the CVs varied between 18% and 49%; with CIC they lowered to 4-7% (n = 5 x 12), i.e. in a range allowing clinical application. It is shown that CIC can be discarded for the measurement of peak thrombin values and replaced by comparison to a reference plasma only if quenching is not a systematic confounder. This was shown to be the case in the set of 139 normal plasmas but not in the set used for determining the intraindividual CVs, a difference that may depend upon preanalytical conditions. PMID:18690357

De Smedt, Erik; Al Dieri, Raed; Spronk, Henri M H; Hamulyak, Karli; ten Cate, Hugo; Hemker, H Coenraad

2008-08-01

194

Thrombin induces epithelial-mesenchymal transition via PAR-1, PKC, and ERK1/2 pathways in A549 cells  

Science.gov (United States)

Thrombin activates protease-activated receptor (PAR)-1 and induces a myofibroblast phenotype in normal lung fibroblasts. The origins of myofibroblasts are resident fibroblasts, fibrocytes, and epithelial-mesenchymal transition (EMT). We investigated the effects of thrombin, an important mediator of interstitial lung fibrosis, on EMT in A549 human alveolar epithelial cells. We show that thrombin induced EMT and collagen I secretion through the activation of PAR-1, and PKC and ERK1/2 phosphorylation in A549 cells. These effects were largely prevented by a specific PAR-1 antagonist, short interfering RNA (siRNA) directed against PAR-1, or specific PKC?/?, ?, and ? inhibitors. These data indicated that interaction with thrombin and alveolar epithelial cells might directly contribute to the pathogenesis of pulmonary fibrosis through EMT. Targeting PAR-1 on the pulmonary epithelium or specific inhibitors to PKC?/?, ?, and ? might stop the fibrotic processes in human idiopathic pulmonary fibrosis by preventing thrombin-induced EMT.

Song, Jeong Sup; Kang, Chun Mi; Park, Chan Kwon; Yoon, Hyung Kyu

2013-01-01

195

Conformational stability of a thrombin-binding peptide derived from the hirudin C-terminus.  

Science.gov (United States)

The COOH-terminal region of hirudin represents an independent functional domain that binds to an anion-binding exosite of thrombin and inhibits the interaction of thrombin with fibrinogen and regulatory proteins in blood coagulation. The thrombin-bound structure of the peptide fragment, hirudin 55-65, has been determined by use of transferred NOE spectroscopy [Ni, F., Konishi, Y., & Scheraga, H. A. (1990) Biochemistry 29, 4479-4489]. The stability of the thrombin-bound conformation has been characterized further by a combined NMR and theoretical analysis of the conformational ensemble accessible by the hirudin peptide. Medium- and long-range NOE's were found for the free hirudin peptide in aqueous solution and in a mixture of dimethyl sulfoxide and water at both ambient (25 degrees C) and low (0 degrees C) temperatures, suggesting that ordered conformations are highly populated in solution. The global folding of these conformations is similar to that in the thrombin-bound state, as indicated by NOE's involving the side-chain protons of residues Phe(56), Ile(59), Pro(60), Tyr(63), and Leu(64). Residues Glu(61), Glu(62), Tyr(63), and Leu(64) all contain approximately 50% of helical conformations calculated from the ratio of the sequential dNN and d alpha N NOE's. Among the helical ensemble, active 3(10)-helical conformations were found by an analysis of the medium-range [(i,i+2) and (i,i+3)] NOE's involving the last six residues of the peptide. An analysis of the side-chain rotamers revealed that, upon binding to thrombin, there may be a rotation around the alpha CH-beta CH bond of Ile(59) such that Ile(59) adopts a gauche- (chi 1 = +60) conformation in contrast to the highly populated trans (chi 1 = -60) found for Ile(59) in the free peptide. However, the thrombin-bound conformation of the hirudin peptide is still an intrinsically stable conformer, and the preferred conformational ensemble of the peptide contains a large population of the active conformation. The apparent preference for a gauche- (chi 1 = +60) side-chain conformation of Ile(59) in the bound state may be explained by the existence of a positively charged arginine residue among the hydrophobic residues in the thrombin exosite. PMID:1547237

Ni, F; Ripoll, D R; Purisima, E O

1992-03-10

196

Percutaneous Thrombin Injection to Complete SMA Pseudoaneurysm Exclusion After Failing of Endograft Placement  

International Nuclear Information System (INIS)

Visceral aneurysms are potentially life-threatening vascular lesions. Superior mesenteric artery (SMA) pseudoaneurysms are a rare but well-recognized complication of chronic pancreatitis. Open surgical repair of such an aneurysm, especially in patients after previous surgical treatment, might be dangerous and risky. Stent graft implantation makes SMA pseudoaneurysm exclusion possible and therefore avoids a major abdominal operation. Percutaneous direct thrombin injection is also one of the methods of treating aneurysms in this area. We report a first case of percutaneous ultrasound-guided thrombin injection to complete SMA pseudoaneurysm exclusion after an unsuccessful endograft placement. Six-month follow-up did not demonstrate any signs of aneurysm recurrence

2005-05-01

197

Traumatic Inferior Gluteal Artery Aneurysm Managed with Emergency Transcatheter Thrombin Injection  

International Nuclear Information System (INIS)

Pseudoaneurysms of the inferior gluteal artery (IGA) are rare and are often caused by trauma. Treatment options vary and include surgery, ultrasound-guided percutaneous thrombin injection, and endovascular procedures such as stent-graft placement, coil embolization, and glue injection. We report a 70-year-old male who presented to the hospital after a road accident with a posttraumatic pseudoaneurysm that was treated by endovascular thrombin embolization. To the best of our knowledge, this is the first reported case of inferior gluteal artery false aneurysm treated by this method.

2010-06-01

198

Application of thrombin powder after tooth extraction in patients receiving anticoagulant therapy  

Directory of Open Access Journals (Sweden)

Full Text Available Patients with extreme hypocoagulation, which occurs either as an effect of some diseases with coagulation deficiency or because of the anticoagulant therapy (ACT, are a risk group for oral surgery. In the last decades decision to change or interrupt ACT before and after the procedure was abandoned and more often local hemostasis was being achieved by combining chemical and biological substances. The success of the surgical hemostasis and thrombin powder combination was tested on the group of 20 patients with ACT. The results were satisfactory despite thrombin powder solubility in the moist oral environment.

Marjanovi? Marjan

2002-01-01

199

[Use of thrombin powder after tooth extraction in patients receiving anticoagulant therapy].  

Science.gov (United States)

Patients with extreme hypocoagulation, which occurs either as an effect of some diseases with coagulation deficiency or because of the anticoagulant therapy (ACT), are a risk group for oral surgery. In the last decades decision to change or interrupt ACT before and after the procedure was abandoned and more often local heamostasis was being achieved by combining chemical and biological substances. The success of the surgical hemostasis and thrombin powder combination was tested on the group of 20 patients with ACT. The results were satisfactory despite thrombin powder solubility in the moist oral environment. PMID:12235745

Marjanovi?, Marjan

2002-01-01

200

Longitudinal assessment of thrombin generation potential in response to alteration of antiplatelet therapy after TIA or ischaemic stroke.  

LENUS (Irish Health Repository)

The impact of changing antiplatelet therapy on thrombin generation potential in patients with ischaemic cerebrovascular disease (CVD) is unclear. We assessed patients within 4 weeks of TIA or ischaemic stroke (baseline), and then 14 days (14d) and >90 days (90d) after altering antiplatelet therapy. Thrombin generation was assessed in platelet poor plasma. Ninety-one patients were recruited. Twenty-four were initially assessed on no antiplatelet therapy, and then after 14d (N = 23) and 90d (N = 8) on aspirin monotherapy; 52 were assessed on aspirin monotherapy, and after 14 and 90 days on aspirin and dipyridamole combination therapy; 21 patients were assessed on aspirin and after 14 days (N = 21) and 90 days (N = 19) on clopidogrel. Peak thrombin generation and endogenous thrombin potential were reduced at 14 and 90 days (p ? 0.04) in the overall cohort. We assessed the impact of individual antiplatelet regimens on thrombin generation parameters to investigate the cause of this effect. Lag time and time-to-peak thrombin generation were unchanged at 14 days, but reduced 90 days after commencing aspirin (p ? 0.009). Lag time, peak thrombin generation and endogenous thrombin potential were reduced at both 14 and 90 days after adding dipyridamole to aspirin (p ? 0.01). Lag time was reduced 14 days after changing from aspirin to clopidogrel (p = 0.045), but this effect was not maintained at 90 days (p = 0.2). This pilot study did not show any consistent effects of commencing aspirin, or of changing from aspirin to clopidogrel on thrombin generation potential during follow-up. The addition of dipyridamole to aspirin led to a persistent reduction in peak and total thrombin generation ex vivo, and illustrates the diverse, potentially beneficial, newly recognised \\'anti-coagulant\\' effects of dipyridamole in ischaemic CVD.

Tobin, W O

2013-02-01

 
 
 
 
201

Topics in Nuclear Astrophysics  

International Nuclear Information System (INIS)

Some topics in nuclear astrophysics are discussed, e.g.: highly evolved stellar cores, stellar evolution (through the temperature analysis of stellar surface), nucleosynthesis and finally the solar neutrino problem. (L.C.)

1982-01-01

202

Sparse Topical Coding  

CERN Document Server

We present sparse topical coding (STC), a non-probabilistic formulation of topic models for discovering latent representations of large collections of data. Unlike probabilistic topic models, STC relaxes the normalization constraint of admixture proportions and the constraint of defining a normalized likelihood function. Such relaxations make STC amenable to: 1) directly control the sparsity of inferred representations by using sparsity-inducing regularizers; 2) be seamlessly integrated with a convex error function (e.g., SVM hinge loss) for supervised learning; and 3) be efficiently learned with a simply structured coordinate descent algorithm. Our results demonstrate the advantages of STC and supervised MedSTC on identifying topical meanings of words and improving classification accuracy and time efficiency.

Zhu, Jun

2012-01-01

203

Related Topics and News  

Science.gov (United States)

Related Topics and News Harold Varmus Appointed to President's Council of Advisors on Science and Technology Harold Varmus Attends White House Signing Harold Varmus Awarded Henry G. Friesen International Prize in Health Research Harold Varmus Featured

204

Medicaid Information by Topic  

Science.gov (United States)

... State Resources Affordable Care Act About Us Medicaid Information by Topic Eligibility Medicaid and CHIP provide health ... cover other population groups (optional eligibility groups). More information is available in the Eligibility section . Benefits States ...

205

Salicylic Acid Topical  

Science.gov (United States)

... to the skin that you are treating with topical salicylic acid unless your doctor tells you that you should: abrasive soaps or cleansers; skin care products that contain alcohol; other medications that are ...

206

Topical photodynamic therapy  

Directory of Open Access Journals (Sweden)

Full Text Available Topical photodynamic therapy is a therapeutic modality in development, thus arises grate interest among dermatologists worldwide. It is an effective therapy for actinic keratosis, superficial BCC and Bowenos disease. Treatment efficacy, good cosmetics, low risk of skin cancer, low invasiveness, low rate of adverse events, facility for treating multiple or large lesions, especially in poor healing sites and, for penile, digital and facial involvement, low general toxicity and possibility of repeating the treatments with the same efficiency, enable topical photodynamic therapy to become increasingly practiced treatment modality. Researching aimed topical photodynamic therapy to prove as a treatment modality for clinical use in other dermatoses, is in experimental phase. To answer the question when dermatologist should consider using topical photodynamic therapy treatment modatility, we are present available date.

Polja?ki Mirjana

2006-01-01

207

Towards Big Topic Modeling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To solve the big topic modeling problem, we need to reduce both time and space complexities of batch latent Dirichlet allocation (LDA) algorithms. Although parallel LDA algorithms on the multi-processor architecture have low time and space complexities, their communication costs among processors often scale linearly with the vocabulary size and the number of topics, leading to a serious scalability problem. To reduce the communication complexity among processors for a better...

Yan, Jian-feng; Zeng, Jia; Liu, Zhi-qiang; Gao, Yang

2013-01-01

208

Mapping topics and topic bursts in PNAS.  

Science.gov (United States)

Scientific research is highly dynamic. New areas of science continually evolve; others gain or lose importance, merge, or split. Due to the steady increase in the number of scientific publications, it is hard to keep an overview of the structure and dynamic development of one's own field of science, much less all scientific domains. However, knowledge of "hot" topics, emergent research frontiers, or change of focus in certain areas is a critical component of resource allocation decisions in research laboratories, governmental institutions, and corporations. This paper demonstrates the utilization of Kleinberg's burst detection algorithm, co-word occurrence analysis, and graph layout techniques to generate maps that support the identification of major research topics and trends. The approach was applied to analyze and map the complete set of papers published in PNAS in the years 1982-2001. Six domain experts examined and commented on the resulting maps in an attempt to reconstruct the evolution of major research areas covered by PNAS. PMID:14978278

Mane, Ketan K; Börner, Katy

2004-04-01

209

Topical treatment of melasma  

Directory of Open Access Journals (Sweden)

Full Text Available Melasma is a common hypermelanotic disorder affecting the face that is associated with considerable psychological impacts. The management of melasma is challenging and requires a long-term treatment plan. In addition to avoidance of aggravating factors like oral pills and ultraviolet exposure, topical therapy has remained the mainstay of treatment. Multiple options for topical treatment are available, of which hydroquinone (HQ is the most commonly prescribed agent. Besides HQ, other topical agents for which varying degrees of evidence for clinical efficacy exist include azelaic acid, kojic acid, retinoids, topical steroids, glycolic acid, mequinol, and arbutin. Topical medications modify various stages of melanogenesis, the most common mode of action being inhibition of the enzyme, tyrosinase. Combination therapy is the preferred mode of treatment for the synergism and reduction of untoward effects. The most popular combination consists of HQ, a topical steroid, and retinoic acid. Prolonged HQ usage may lead to untoward effects like depigmentation and exogenous ochronosis. The search for safer alternatives has given rise to the development of many newer agents, several of them from natural sources. Well-designed controlled clinical trials are needed to clarify their role in the routine management of melasma.

Bandyopadhyay Debabrata

2009-01-01

210

(-)-Epigallocatechin-3-gallate decreases thrombin/paclitaxel-induced endothelial tissue factor expression via the inhibition of c-Jun terminal NH2 kinase phosphorylation  

International Nuclear Information System (INIS)

Patients with paclitaxel-eluting stents are concerned with stent thrombosis caused by premature discontinuation of dual antiplatelet therapy or clopidogrel resistance. This study investigates the effect of (-)-epigallocatechin-3-gallate (EGCG) on the expression of thrombin/paclitaxel-induced endothelial tissue factor (TF) expressions in human aortic endothelial cells (HAECs). EGCG was nontoxic to HAECs at 6 h up to a concentration of 25 ?mol/L. At a concentration of 25 ?mol/L, EGCG pretreatment potently inhibited both thrombin-stimulated and thrombin/paclitaxel-stimulated endothelial TF protein expression. Thrombin and thrombin/paclitaxel-induced 2.6-fold and 2.9-fold increases in TF activity compared with the control. EGCG pretreatment caused a 29% and 38% decrease in TF activity on thrombin and thrombin/paclitaxel treatment, respectively. Real-time polymerase chain reaction (PCR) showed that thrombin and thrombin/paclitaxel-induced 3.0-fold and 4.6-fold TF mRNA expressions compared with the control. EGCG pretreatment caused an 82% and 72% decrease in TF mRNA expression on thrombin and thrombin/paclitaxel treatment, respectively. The c-Jun terminal NH2 kinase (JNK) inhibitor SP600125 reduced thrombin/paclitaxel-induced TF expression. Furthermore, EGCG significantly inhibited the phosphorylation of JNK to 49% of thrombin/paclitaxel-stimulated HAECs at 60 min. Immunofluorescence assay did not show an inhibitory effect of EGCG on P65 NF-?B nuclear translocation in the thrombin/paclitaxel-stimulated endothelial cells. In conclusion, EGCG can inhibit TF expression in thrombin/paclitaxel-stimulated endothelial cells via the inhibition of JNK phosphorylation. The unique property of EGCG may be used to develop a new drug-eluting stent by co-coating EGCG and paclitaxel.

2010-01-01

211

(-)-Epigallocatechin-3-gallate decreases thrombin/paclitaxel-induced endothelial tissue factor expression via the inhibition of c-Jun terminal NH2 kinase phosphorylation  

Energy Technology Data Exchange (ETDEWEB)

Patients with paclitaxel-eluting stents are concerned with stent thrombosis caused by premature discontinuation of dual antiplatelet therapy or clopidogrel resistance. This study investigates the effect of (-)-epigallocatechin-3-gallate (EGCG) on the expression of thrombin/paclitaxel-induced endothelial tissue factor (TF) expressions in human aortic endothelial cells (HAECs). EGCG was nontoxic to HAECs at 6 h up to a concentration of 25 {mu}mol/L. At a concentration of 25 {mu}mol/L, EGCG pretreatment potently inhibited both thrombin-stimulated and thrombin/paclitaxel-stimulated endothelial TF protein expression. Thrombin and thrombin/paclitaxel-induced 2.6-fold and 2.9-fold increases in TF activity compared with the control. EGCG pretreatment caused a 29% and 38% decrease in TF activity on thrombin and thrombin/paclitaxel treatment, respectively. Real-time polymerase chain reaction (PCR) showed that thrombin and thrombin/paclitaxel-induced 3.0-fold and 4.6-fold TF mRNA expressions compared with the control. EGCG pretreatment caused an 82% and 72% decrease in TF mRNA expression on thrombin and thrombin/paclitaxel treatment, respectively. The c-Jun terminal NH2 kinase (JNK) inhibitor SP600125 reduced thrombin/paclitaxel-induced TF expression. Furthermore, EGCG significantly inhibited the phosphorylation of JNK to 49% of thrombin/paclitaxel-stimulated HAECs at 60 min. Immunofluorescence assay did not show an inhibitory effect of EGCG on P65 NF-{kappa}B nuclear translocation in the thrombin/paclitaxel-stimulated endothelial cells. In conclusion, EGCG can inhibit TF expression in thrombin/paclitaxel-stimulated endothelial cells via the inhibition of JNK phosphorylation. The unique property of EGCG may be used to develop a new drug-eluting stent by co-coating EGCG and paclitaxel.

Wang, Huang-Joe [Institute of Biotechnology, National Tsing Hua University, No. 101, Section 2, Kuang Fu Road, Hsinchu 30013, Taiwan (China); Division of Cardiology, Department of Medicine, China Medical University Hospital, No. 2, Yuh-Der Road, Taichung 40447, Taiwan (China); Lo, Wan-Yu [Department of Medical Research, China Medical University Hospital, No. 2, Yuh-Der Road, Taichung 40447, Taiwan (China); Graduate Integration of Chinese and Western Medicine, China Medical University, No. 91, Hsueh-Shih Road, Taichung 40402, Taiwan (China); Lu, Te-Ling [School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road, Taichung 40402, Taiwan (China); Huang, Haimei, E-mail: hmhuang@life.nthu.edu.tw [Institute of Biotechnology, National Tsing Hua University, No. 101, Section 2, Kuang Fu Road, Hsinchu 30013, Taiwan (China)

2010-01-01

212

Recombinant Technology and Probiotics  

Directory of Open Access Journals (Sweden)

Full Text Available Recombinant technology has led the way to monumental advances in the development of useful molecules, including the development of safe probiotics. The development of novel approaches using recombinant technology and probiotics that allow accurate targeting of therapeutics to the mucosa is an interesting area of research. The creation and use of recombinant probiotics expressing recombinantovalbumin, recombinant ovalbumin mutants and yet-to-be-designed recombinant hypo/non-allergenic molecules offer the opportunity to further investigate their effects for food, nutrition, environment andhealth. This review highlights advances in native probiotics and recombinant probiotics expressing native and recombinant molecules for food, nutrition, environment and health.

Icy D’Silva

2011-09-01

213

Health Topic XML File Description  

Science.gov (United States)

... topic URL. The URL for the corresponding health topic page on MedlinePlus. Example: url="http://www.nlm.nih. ... related topics shown on the left sidebar of topic pages and other pages. Example: topic title="Abdominal ...

214

IP Internal Movement and Topicalization  

Science.gov (United States)

In this dissertation, I investigate the phenomenon of internal topicalization cross-linguistically, using Chinese as a starting point. Internal topicalization refers to constructions in which a topic phrase is placed between the subject and the verb (in contrast to external topicalization, which involves a topic in the CP domain). I argue that…

Kuo, Pei-Jung

2009-01-01

215

Increased thrombin generation measured in the presence of thrombomodulin in women with early pregnancy loss.  

Science.gov (United States)

Compared with 537 parous controls with no history of pregnancy loss, a lower thrombomodulin-related inhibition of the endogenous thrombin potential was measured in 264 cases with previous unexplained pregnancy loss, especially when losses occurred between 9 and 12 weeks of gestation. Adjusting age, protein S, factor VIII, factor V Leiden, and prothrombin G20210A did not change the results. PMID:21130429

de Saint Martin, Luc; Duchemin, Jérôme; Bohec, Caroline; Couturaud, Francis; Mottier, Dominique; Collet, Michel; Blouch, Marie-Thérèse; Pasquier, Elisabeth

2011-04-01

216

Percutaneous thrombin injection for the treatment of a post-pancreatitis pseudoaneurysm  

Energy Technology Data Exchange (ETDEWEB)

Visceral artery pseudoaneurysms are often treated surgically or by transcatheter embolisation. We report a case of a pseudoaneurysm in a patient with chronic pancreatitis, which was successfully occluded by percutaneous injection of thrombin into the pseudoaneurysmal sac as a first-line management. (orig.)

Puri, S.; Nicholson, A.A.; Breen, D.J. [Dept. of Radiology, Hull Royal Infirmary, Hull (United Kingdom)

2003-12-01

217

Thrombin binds to a high-affinity approximately 900,000-dalton site on human platelets  

International Nuclear Information System (INIS)

The functional sizes of the binding sites for thrombin on human platelets and isolated membranes have been determined by the technique of radiation inactivation: similar results were obtained. Independent studies using different radiation doses (0, 3, and 48 Mrad) and different thrombin concentrations (10(-10), 10(-8), and 10(-6) M) confirmed the presence of three binding sites with functional sizes of 900,000, 30,000, and 4000 daltons. The binding site of lowest apparent size (4000 daltons) probably corresponds to what has been termed nonspecific binding since its dissociation constant (2900 nM) is well outside the physiological range. The site of intermediate size (30,000 daltons) is also probably not involved in platelet activation since its dissociation constant (11 nM) is also beyond the concentration range required for activation, although it may be involved in other aspects of platelet-thrombin interaction. The sites with the largest functional size are probably important in platelet function since their dissociation constant (0.3 nM) is in the range required for platelet activation. The functional size of these sites (900,000 daltons) suggests that the high-affinity site for thrombin binding to platelets may involve a multimolecular complex of membrane components

1985-01-01

218

Rac inhibits thrombin-induced Rho activation: evidence of a Pak-dependent GTPase crosstalk  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract The strict spatio-temporal control of Rho GTPases is critical for many cellular functions, including cell motility, contractility, and growth. In this regard, the prototypical Rho family GTPases, Rho, Rac, and Cdc42 regulate the activity of each other by a still poorly understood mechanism. Indeed, we found that constitutively active forms of Rac inhibit stress fiber formation and Rho stimulation by thrombin. Surprisingly, a mutant of Rac that is unable to activate Pak1 failed to inhibit thrombin signaling to Rho. To explore the underlying mechanism, we investigated whether Pak1 could regulate guanine nucleotide exchange factors (GEFs for Rho. We found that Pak1 associates with P115-RhoGEF but not with PDZ-RhoGEF or LARG, and knock down experiments revealed that P115-RhoGEF plays a major role in signaling from thrombin receptors to Rho in HEK293T cells. Pak1 binds the DH-PH domain of P115-RhoGEF, thus suggesting a mechanism by which Rac stimulation of Pak1 may disrupt receptor-dependent Rho signaling. In agreement, expression of a dominant-negative Pak-Inhibitory Domain potentiated the activation of Rho by thrombin, and prevented the inhibition of Rho by Rac. These findings indicate that Rac interferes with receptor-dependent Rho stimulation through Pak1, thus providing a mechanism for cross-talk between these two small-GTPases.

Rosenfeldt Hans

2006-12-01

219

Treatment of a Splenic Artery Pseudoaneurysm by Endoscopic Ultrasound-Guided Thrombin Injection  

International Nuclear Information System (INIS)

We present a case of a splenic artery pseudoaneurysm secondary to pancreatitis that was successfully treated by transgastric injection of thrombin under endoscopic ultrasound guidance. There has been no recurrence on follow-up CT angiography, and thus complex surgery or endovascular intervention has been avoided

2007-06-01

220

Percutaneous Ultrasound-Guided Thrombin Injection as First-Line Treatment of Pancreatic Pseudoaneurysm  

International Nuclear Information System (INIS)

Pancreatic pseudoaneurysms are a rare but potentially fatal complication of pancreatitis. Surgical intervention and transcatheter embolization are not always feasible therapeutic options. In this report we present a case of a pseudoaneurysm secondary to pancreatitis which, despite being angiographically invisible, was successfully embolized with a single ultrasound-guided percutaneous injection of thrombin

2007-06-01

 
 
 
 
221

Aplysillin A, a thrombin receptor antagonist from the marine sponge Aplysina fistularis fulva.  

Science.gov (United States)

Aplysillin A [1], an unusual disulfate ester of a 1,4-diphenyl-1,3-butadiene, was isolated from a deep water specimen of a sponge of the genus Aplysina. Its structure was determined through spectroscopic methods. The compound weakly inhibited binding to the thrombin receptor with an IC50 value of 20 microM. PMID:7673943

Gulavita, N K; Pomponi, S A; Wright, A E; Garay, M; Sills, M A

1995-06-01

222

Prolyl endopeptidase and thrombin inhibitory diterpenoids from the bark of Xylopia aethiopica.  

Science.gov (United States)

The inhibitory effects of seven diterpenes, belonging to three different structural classes and isolated from the bark of Xylopia aethiopica, were investigated against the enzymes prolyl endopeptidase (PEP) and alpha-thrombin. Five compounds exhibited inhibitory activity against them. PMID:16195597

Diderot, Noungoue Tchamo; Silvere, Ngouela; Yasin, Amsha; Zareen, Seema; Fabien, Zelefack; Etienne, Tsamo; Choudhary, M Iqbal; Atta-Ur-Rahman

2005-09-01

223

Development of a Multiplex Sandwich Aptamer Microarray for the Detection of VEGF165 and Thrombin  

Directory of Open Access Journals (Sweden)

Full Text Available In this work we have developed a multiplex microarray system capable of detecting VEGF165 and thrombin. We recently described a Sandwich Aptamer Microarray (SAM for thrombin detection feasible for use in multiplex microarrays; here we describe a new aptasensor for VEGF165 detection employing Vap7 and VEa5, two DNA aptamers recognizing different sites of the protein. The aptamers were modified to be adapted to the solid phase platform of SAM and their capability to simultaneously recognize VEGF165 by forming a ternary complex was analyzed in solution. Having so defined the best tandem arrangement of modified aptamers, we set up the aptasensor for VEGF165, and finally analyzed the multiplex system with the two aptasensors for the simultaneous detection of VEGF165 and thrombin. The results indicate that each sandwich is specific, even when the two proteins are mixed. The system performance is consistent with the behavior evidenced by the biochemical analysis, which proves to be valuable to drive the evaluation and refinement of aptamers prior to or along the development of a detection platform. Since thrombin upregulates VEGF expression, the simultaneous recognition of these two proteins could be useful in the analysis of biomarkers in pathologies characterized by neo-angiogenesis.

Anna Meneghello

2013-10-01

224

An off-on-off electrochemiluminescence approach for ultrasensitive detection of thrombin.  

Science.gov (United States)

This work demonstrates an aptasensor for ultrasensitive electrochemiluminescence (ECL) detection of thrombin based on an "off-on-off" approach. The system is composed of an Eu(3+)-doped CdS nanocrystals (CdS:Eu NCs) film on glassy carbon electrode (GCE) as ECL emitter. Then gold nanoparticles (AuNPs) labeled hairpin-DNA probe (ssDNA1) containing thrombin-binding aptamer (TBA) sequence was linked on the NCs film, which led to ECL quenching (off) as a result of Förster-resonance energy transfer (FRET) between the CdS:Eu NC film and the proximal AuNPs. Upon the occurrence of hybridization with its complementary DNA (ssDNA2), an ECL enhancement (on) occurred owing to the interactions of the excited CdS:Eu NCs with ECL-induced surface plasmon resonance (SPR) in AuNPs at large separation. Thrombin could induce ssDNA1 forming a G-quadruplex and cause the AuNPs to be close to CdS:Eu NCs film again, which resulted in an enhanced ECL quenching (off). This "off-on-off" system showed a maximum 7.4-fold change of ECL intensity due to the configuration transformation of ssDNA1 and provides great sensitivity for detection of thrombin in a wide detection range from 50aM to 1pM. PMID:24699694

Deng, Li; Du, Ying; Xu, Jing-Juan; Chen, Hong-Yuan

2014-09-15

225

Severe decrease of cyclosporine levels in a heart transplant recipient receiving the direct thrombin inhibitor argatroban.  

Science.gov (United States)

: This case report is about a suspected interaction between argatroban, a direct thrombin inhibitor, and cyclosporine, which occurred in a 60-year-old patient after a second heart transplantation. We explored 4 possible mechanisms of interaction, which are an analytical interference, an idiopathic hemodilution, an increase of renal and hepatic clearance, and a metabolic drug-drug interaction. PMID:24365983

Sanchez, Romain; Picard, Nicolas; Mouly-Bandini, Annick; Chalvignac, Virginie; Lacarelle, Bruno; Sampol-Manos, Emmanuelle

2014-06-01

226

In vivo catabolism of human heparin cofactor II and its complex with thrombin  

Energy Technology Data Exchange (ETDEWEB)

The plasma clearance of human heparin cofactor II (HC) and its complex with thrombin (HC-T) was studied in mice and compared to the clearance of two other plasma proteinase inhibitor complexes: antithrombin III-thrombin (AT-T) and ..cap alpha.. 1-proteinase inhibitor-elastase (..cap alpha.. /sub 1/PI-E). Purified HC was labelled with /sup 125/I without loss of activity as assessed by kinetic analysis of thrombin inhibition and by ability to form a detergent-resistant complex with thrombin. /sup 125/I-HC cleared from the circulation with a t1/2 of 80 min; /sup 125/I-HC-T cleared with a t1/2 of 10 min. When coinjected, a 2500-fold molar excess of unlabelled HC-T partially blocked the clearance of /sup 125/I-HC-T (t1/2 of 53 min), suggesting the involvement of a receptor-mediated process in the catabolism of HC-T. Coinjection of a 1500-fold molar excess of AT-T also slowed the clearance of /sup 125/I-HC-T (t1/2 of 29 min); a 2000-fold molar excess of ..cap alpha.. /sub 1/PI-E further competed for /sup 125/I-HC-T recovered at autopsy was localized to the liver; similar results have been obtained for AT-T and ..cap alpha.. /sub 1/PI-trypsin.

Pratt, C.W.; Church, F.C.; Pizzo, S.V.

1987-05-01

227

In vivo catabolism of human heparin cofactor II and its complex with thrombin  

International Nuclear Information System (INIS)

The plasma clearance of human heparin cofactor II (HC) and its complex with thrombin (HC-T) was studied in mice and compared to the clearance of two other plasma proteinase inhibitor complexes: antithrombin III-thrombin (AT-T) and ? 1-proteinase inhibitor-elastase (? 1PI-E). Purified HC was labelled with 125I without loss of activity as assessed by kinetic analysis of thrombin inhibition and by ability to form a detergent-resistant complex with thrombin. 125I-HC cleared from the circulation with a t1/2 of 80 min; 125I-HC-T cleared with a t1/2 of 10 min. When coinjected, a 2500-fold molar excess of unlabelled HC-T partially blocked the clearance of 125I-HC-T (t1/2 of 53 min), suggesting the involvement of a receptor-mediated process in the catabolism of HC-T. Coinjection of a 1500-fold molar excess of AT-T also slowed the clearance of 125I-HC-T (t1/2 of 29 min); a 2000-fold molar excess of ? 1PI-E further competed for 125I-HC-T recovered at autopsy was localized to the liver; similar results have been obtained for AT-T and ? 1PI-trypsin

1987-05-01

228

Aptamer modified organic-inorganic hybrid silica monolithic capillary columns for highly selective recognition of thrombin.  

Science.gov (United States)

A novel kind of aptamer modified organic-inorganic hybrid silica monolithic capillary column has been developed, via the covalent bonding of 5'-NH(2)-modified aptamer for human ?-thrombin on hybrid silica monolith, prepared by sol-gel method, with tetraethoxysilane and 3-aminopropyltriethoxysilane as precursors. Due to the large specific surface area of the hybrid matrix, the average coverage density of aptamer reached 568 pmol/?L, and the thrombin binding capacity was 1.15 ?g/?L, 14 times higher than that of aptamer modified open tubular capillaries. By such an affinity capillary column, the limit of detection of thrombin was decreased to 3.4 nM with a UV detector. Furthermore, even when thrombin was mixed with 1000 times more concentrated human serum, it could be selectively enriched and detected with the signal-to-noise ratio as ca.10. These results indicate that the developed preparation strategy for aptamer based hybrid silica monolithic capillary column might provide an effective method to achieve highly selective recognition of trace targets. PMID:23137349

Deng, Nan; Liang, Zhen; Liang, Yu; Sui, Zhigang; Zhang, Liyuan; Wu, Qi; Yang, Kaiguang; Zhang, Lihua; Zhang, Yukui

2012-12-01

229

Thrombin based gelatin matrix and fibrin sealant mediated clot formation in the presence of clopidogrel  

Science.gov (United States)

Background Platelet inhibitors are commonly used to reduce the risk of atherothrombotic events. The aim of this study was to determine the impact of platelet inhibitors, specifically clopidogrel and aspirin, on clot kinetics, strength, and/or structure during the use of thrombin based gelatin matrices and fibrin sealants. Methods Blood was collected and heparinized from donors on clopidogrel (and aspirin) and age matched control donors. Blood component analysis, whole blood platelet aggregometry, and activated clotting time (ACT) were used to monitor compliance to therapy and identify any differences between donor groups. Clot kinetics and strength were analyzed using thrombelastography (TEG). Field Emission Scanning Electron Microscopy (FESEM) was used to analyze clot structure. Results Blood component profiles were similar for both donor groups. Aggregometry indicated that aggregation response to adenosine diphosphate (ADP) for clopidogrel donors was 12% of that for the controls (p?=?0.0021), an expected result of clopidogrel induced platelet inhibition. However, blood from both donor groups had an elevated thrombin induced aggregation response. Heparinization of donor blood resulted in similarly elevated ACTs for both donor groups. TEG results indicated similar clot kinetics and strength between clopidogrel and control donor groups for blood alone and when clotting was induced using thrombin based gelatin matrices and fibrin sealants. FESEM images supported TEG findings in that similar morphologies were observed in ex vivo formed clots from both donor groups when thrombin based gelatin matrices and fibrin sealants were used. Conclusion These results suggest that platelet inhibitors do not negatively impact clot kinetics, strength, and structure when clotting is initiated with thrombin based gelatin matrices and fibrin sealants.

2014-01-01

230

The Topic-Prominence Parameter  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This article aims to recast the properties of topic-prominent languages and their differences from subject-prominent languages as documented in the functionalist literature into the framework of the Principle-and-Parameter approach. It provides a configurational definition of the topic construction called Topic Phrase (TP), with the topic marker as its head. The availablity of TP enables topic prominent languages to develop various topic structures with properties such as morphological markin...

Xu, Liejiong

2000-01-01

231

Topic Identification in Discourse  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper proposes a corpus-based language model for topic identification. We analyze the association of noun-noun and noun-verb pairs in LOB Corpus. The word association norms are based on three factors: 1) word importance, 2) pair co-occurrence, and 3) distance. They are trained on the paragraph and sentence levels for noun-noun and noun-verb pairs, respectively. Under the topic coherence postulation, the nouns that have the strongest connectivities with the other nouns a...

Chen, Kuang-hua

1995-01-01

232

Conventional topical delivery systems.  

Science.gov (United States)

Effective dermatologic therapy depends on both the active drug and the properties of the delivery system. A topical delivery system, or vehicle, is defined as the substance that carries a specific drug into contact with and through the skin. The challenge to topical drug delivery is the transport across the skin barrier. Depending on the delivery system, penetration of the active drug can be quite variable and this is largely due to the physiochemical properties of the constituent components of that vehicle. Selection of the appropriate drug delivery system will depend on the active, anatomic site of disease and patient preferences. PMID:22353153

Weiss, Stefan C

2011-01-01

233

Topics in Physical Mathematics  

CERN Multimedia

This title adopts the view that physics is the primary driving force behind a number of developments in mathematics. Previously, science and mathematics were part of natural philosophy and many mathematical theories arose as a result of trying to understand natural phenomena. This situation changed at the beginning of last century as science and mathematics diverged. These two fields are collaborating once again; 'Topics in Mathematical Physics' takes the reader through this journey. The author discusses topics where the interaction of physical and mathematical theories has led to new points o

Marathe, Kishore

2010-01-01

234

Topical negative pressure therapy.  

Science.gov (United States)

Topical negative pressure therapy (TNP) has been available for clinical use in wound management since the late 1990s. It has been shown to be of particular benefit for the treatment of chronic nonhealing wounds and has also recently been positively linked to wound bed preparation. PMID:12640796

Collier, Mark

235

Selected topics in magnetism  

CERN Document Server

Part of the ""Frontiers in Solid State Sciences"" series, this volume presents essays on such topics as spin fluctuations in Heisenberg magnets, quenching of spin fluctuations by high magnetic fields, and kondo effect and heavy fermions in rare earths amongst others.

Gupta, L C

1993-01-01

236

Topical anesthesia in phacoemulsification  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose : To evaluate the efficacy of topical anesthesia; topical Benoxinate 0.4% (Oxybuprocaine and Xylocaine (Lidocaine gel, in selected cataract patients as an alternative to peribulbar or retrobulbar block anesthesia during cataract surgery. Materials and Methods : Prospective non-comparative evaluation of patients? and surgeon?s satisfaction at the end of the procedure. Three hundred patients (300 eyes were included in the study. The procedure was explained to patients with details regarding what will happen and what to expect during surgery. All patients received topical anesthesia with Benoxinate 0.4% eye drops and Xylocaine gel 2%. All surgeries were done by the same surgeon using the same machine (updated LEGACY phacoemulsifier, Alcon and approach (clear corneal incision and followed by a foldable intraocular lens (IOL implantation. Results : None of the patients had severe pain during the procedure; only 2% (six of 300 required use of intravenous sedation (Propofol, both the surgeon?s and the patients? satisfaction were high. Eye movements and blepharospasm were not significant problems, and no serious complications occurred. Rate of vitreous loss due to posterior capsule tear/rupture was within literature reported range and not different from our previous experience. Conclusion : Topical anesthesia is a satisfactory and safe alternative to retrobulbar and peribulbar anesthesia for clear corneal phacoemulsification and intraocular lens implantation in selected cataract patients in the hands of experienced cataract surgeon.

Waheeb Saad

2010-01-01

237

Topics in quantum theory  

International Nuclear Information System (INIS)

Topics in the Yang-Mills theories of strong interactions and the quantum theories of gravity are examined, using the path integral approach, including; Yang-Mills instantons in curved spacetimes, Israel-Wilson metrics, Kaehler spacetimes, instantons and anti-instantons. (U.K.)

1980-01-01

238

Current Topics in Photovoltaics  

Energy Technology Data Exchange (ETDEWEB)

The first volume of 'Current Topics in Photovoltaics' contains five chapters which review different types of solar cells. These include heterojunction solar cells, Cu-ternary chalcopyrite solar cells, amorphous silicon solar cells, advanced concentrator solar cells and cadmium sulphide - copper sulphide solar cells. All five chapters were selected and indexed separately.

Coutts, T.J.; Meakin, J.D. (eds.)

1985-01-01

239

Ciclopirox Topical Solution  

Science.gov (United States)

Ciclopirox topical solution is used along with regular nail trimming to treat fungal infections of the fingernails and toenails (an infection ... Ciclopirox comes as a solution to apply to nails and the skin immediately surrounding and under the nails. It is usually applied once a day. ...

240

LD Topics: Math & Dyscalculia  

Science.gov (United States)

This collection of articles for parents and educators addresses learning disabilities in the area of mathematics. The articles address a variety of topics, including strategies for working with children with dyscalculia, parent-teacher collaboration, identification of disabilities, use of technology, and developing number sense.

2011-01-01

 
 
 
 
241

Diffusion controlled initial recombination  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work addresses nucleation rates in systems with strong initial recombination. Initial (or `geminate') recombination is a process where a dissociated structure (anion, vortex, kink etc.) recombines with its twin brother (cation, anti-vortex, anti-kink) generated in the same nucleation event. Initial recombination is important if there is an asymptotically vanishing interaction force instead of a generic saddle-type activation barrier. At low temperatures, initial recombi...

Christen, T.; Buttiker, M.

1997-01-01

242

Formation of lipoxins and leukotrienes during receptor-mediated interactions of human platelets and recombinant human granulocyte/macrophage colony-stimulating factor-primed neutrophils  

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The generation of lipoxygenase products of arachidonic acid is considered an important event in inflammation. This study demonstrates the levels of both lipoxins and leukotrienes (LTC4, LTD4, LTB4, and omega-oxidized LTB4) generated from endogenous sources of arachidonate by PMN primed with recombinant human granulocyte/macrophage colony- stimulating factor and in coincubations with platelets (1:1 to 1:100 ratio). Upon exposure to receptor-mediated stimuli (FMLP and thrombin), the levels of l...

1990-01-01

243

Induction of MMP-9 release from human dermal fibroblasts by thrombin: involvement of JAK/STAT3 signaling pathway in MMP-9 release  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background It has been recognized that dermal fibroblasts and matrix metalloproteases (MMP play crucial roles in wound healing process in skin. Thrombin was found to stimulate IL-8 release from human dermal fibroblasts (HDFs. However, little is known of the effect of thrombin on secretion of MMPs from dermal fibroblasts. In the present study, the influence of thrombin on proMMP-2 and proMMP-9 activity release from primary cultured HDFs, and its potential signaling pathways were investigated. Results The results showed that thrombin induced proMMP-9, but not proMMP-2 release from HDFs in a dose dependent manner at 6 h following incubation. Thrombin also upregulated expression of proMMP-9 mRNA in HDFs. Hirudin completely abolished the action of thrombin on HDFs. An agonist peptide of protease-activated receptor-1, SFLLR-NH2 stimulated an enhanced release of proMMP-9 from HDFs. AG490, an inhibitor of STAT3 inhibited basal and thrombin-provoked proMMP-9 release and phosphorylation of STAT3. PD98059, an inhibitor of MAPK and LY294002, an inhibitor PI3K failed to significantly inhibit thrombin induced proMMP-9 release. Conclusion Thrombin is a potent stimulus of proMMP-9 release from HDFs. Thrombin induced proMMP-9 release is most likely through activation of PAR-1. JAK/STAT3 signaling pathway is involved in proMMP-9 release from HDFs.

He Shaoheng

2007-05-01

244

New topical antifungal drugs.  

Science.gov (United States)

The new antifungal drugs used for topical treatment of superficial, skin and mucosal mycoses are reviewed. Amorolfine and allylamines (naftifine and terbinafine) are promising original molecules with new and different modes of action against fungi. Rilopirox is a new pyridone derivative under study. A great number of azole derivatives, such as oxiconazole, isoconazole, sulconazole, and terconazole, are used as topical antifungals. Three of them are synthesized in Barcelona by pharmaceutical laboratories: sertaconazole, flutrimazole and eberconazole. All of them are now in the register process for commercialization. The combination of antifungals with active products, such as keratoplastics, is used mainly for the treatment of onychomycoses; 40% urea associated with 1% bifonazole has shown high efficacy for this indication. PMID:8118161

Torres-Rodríguez, J M

1993-01-01

245

Kernel Topic Models  

CERN Document Server

Latent Dirichlet Allocation models discrete data as a mixture of discrete distributions, using Dirichlet beliefs over the mixture weights. We study a variation of this concept, in which the documents' mixture weight beliefs are replaced with squashed Gaussian distributions. This allows documents to be associated with elements of a Hilbert space, admitting kernel topic models (KTM), modelling temporal, spatial, hierarchical, social and other structure between documents. The main challenge is efficient approximate inference on the latent Gaussian. We present an approximate algorithm cast around a Laplace approximation in a transformed basis. The KTM can also be interpreted as a type of Gaussian process latent variable model, or as a topic model conditional on document features, uncovering links between earlier work in these areas.

Hennig, Philipp; Herbrich, Ralf; Graepel, Thore

2011-01-01

246

Topics in molecular interactions  

International Nuclear Information System (INIS)

This volume deals with a variety of problems in intermolecular interactions. These fall into two groups. The first contains important topics which have not recently been dealt with in an authoritative fashion, such as the information given by studying hindered internal rotation. The second group contains contributions based largely on nuclear magnetic resonance work. Nuclear spin relaxation studies have led to intimate knowledge concerning association effects. The approach developed principally at the Karlsruhe laboratory is described. Also included is a second experimental chapter devoted to the way in which light scattering studies provide information on multipole forces in molecular interactions. Other topics based on NMR studies show how this technique yields valuable information on molecular and ion-molecule interactions respectively. (Auth.)

1985-01-01

247

Balloon-assisted ultrasound-guided thrombin injection of a pseudoaneurysm in the posterior tibial artery: A case report  

International Nuclear Information System (INIS)

An ultrasound-guided direct injection of thrombin is currently the first choice of treatment for the postcatheterization pseudoaneurysm, mainly in the femoral artery. A pseudoaneurysm in the posterior tibial artery is very rare, so there are not enough reports about proper treatment yet. We report a case of a balloon-assisted injection of thrombin under ultrasonography-guidance to manage a pseudoaneurysm in the posterior tibial artery and concurrently to prevent a distal artery embolization.

2014-05-01

248

Balloon-assisted ultrasound-guided thrombin injection of a pseudoaneurysm in the posterior tibial artery: A case report  

Energy Technology Data Exchange (ETDEWEB)

An ultrasound-guided direct injection of thrombin is currently the first choice of treatment for the postcatheterization pseudoaneurysm, mainly in the femoral artery. A pseudoaneurysm in the posterior tibial artery is very rare, so there are not enough reports about proper treatment yet. We report a case of a balloon-assisted injection of thrombin under ultrasonography-guidance to manage a pseudoaneurysm in the posterior tibial artery and concurrently to prevent a distal artery embolization.

Lee, Taeg Ki; Jeon, Yong Sun; Hong, Kee Chun; Cho, Soon Gu; Kim, Eu Gene [Inha University School of Medicine, Incheon (Korea, Republic of)

2014-05-15

249

Inhibition of the Tissue Factor-Thrombin Pathway Limits Infarct Size after Myocardial Ischemia-Reperfusion Injury by Reducing Inflammation  

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Functional inhibition of tissue factor (TF) has been shown to improve coronary blood flow after myocardial ischemia/reperfusion (I/R) injury. TF initiates the coagulation protease cascade, resulting in the generation of the serine protease thrombin and fibrin deposition. Thrombin can also contribute to an inflammatory response by activating various cell types, including vascular endothelial cells. We used a rabbit coronary ligation model to investigate the role of TF in acute myocardial I/R i...

Erlich, Jonathan H.; Boyle, Edward M.; Labriola, Joanne; Kovacich, J. Craig; Santucci, Richard A.; Fearns, Colleen; Morgan, Elizabeth N.; Yun, Wang; Luther, Thomas; Kojikawa, Osamu; Martin, Thomas R.; Pohlman, Timothy H.; Verrier, Edward D.; Mackman, Nigel

2000-01-01

250

Topical Therapies for Pruritus  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Itch, or pruritus, is the predominant symptom associated with acute and chronic cutaneous disease and in some cases, may be debilitating. To date, there is no single universally effective anti-itch treatment. As the pathophysiology of itch in most cutaneous or systemic disorders remains unclear, anti-pruritic therapy is often directed against a variety of targets, including the epidermal barrier, immune system, or the nervous system. Topical therapy is the mainstay of dermatologic management ...

Elmariah, Sarina B.; Lerner, Ethan A.

2011-01-01

251

Deletion of the thrombin cleavage domain of osteopontin mediates breast cancer cell adhesion, proteolytic activity, tumorgenicity, and metastasis  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Osteopontin (OPN is a secreted phosphoprotein often overexpressed at high levels in the blood and primary tumors of breast cancer patients. OPN contains two integrin-binding sites and a thrombin cleavage domain located in close proximity to each other. Methods To study the role of the thrombin cleavage site of OPN, MDA-MB-468 human breast cancer cells were stably transfected with either wildtype OPN (468-OPN, mutant OPN lacking the thrombin cleavage domain (468-?TC or an empty vector (468-CON and assessed for in vitro and in vivo functional differences in malignant/metastatic behavior. Results All three cell lines were found to equivalently express thrombin, tissue factor, CD44, ?v?5 integrin and ?1 integrin. Relative to 468-OPN and 468-CON cells, 468-?TC cells expressing OPN with a deleted thrombin cleavage domain demonstrated decreased cell adhesion (p in vitro. Furthermore, injection of 468-?TC cells into the mammary fat pad of nude mice resulted in decreased primary tumor latency time (p Conclusions The results presented here suggest that expression of thrombin-uncleavable OPN imparts an early tumor formation advantage as well as a metastatic advantage for breast cancer cells, possibly due to increased proteolytic activity and decreased adhesion and apoptosis. Clarification of the mechanisms responsible for these observations and the translation of this knowledge into the clinic could ultimately provide new therapeutic opportunities for combating breast cancer.

Postenka Carl O

2011-01-01

252

Nafamostat mesilate attenuates neuronal damage in a rat model of transient focal cerebral ischemia through thrombin inhibition  

Science.gov (United States)

Evidence suggests that thrombin, a blood coagulation serine protease, mediates neuronal injury in experimental cerebral ischemia. Here, we test the hypothesis that nafamostat mesilate, a serine protease inhibitor, may ameliorate ischemia-induced neuronal damage through thrombin inhibition after ischemic stroke. Focal ischemia was induced in adult Sprague-Dawley rats by occlusion of the middle cerebral artery for 2?hours followed by 22?hours of reperfusion. The administration of nafamostat mesilate during ischemia and reperfusion reduced the brain infarct volume, edema volume and neurological deficit. Thrombin expression and activity in the ipsilateral striatum were increased after ischemia, whereas the administration of nafamostat mesilate significantly inhibited thrombin expression and activity. Immunostaining showed that the majority of thrombin was expressed in neurons. TUNEL staining showed that nafamostat mesilate reduced the number of dying cells during ischemia. A rat behavioral test showed that nafamostat mesilate treatment significantly improved the learning ability of ischemic rats. These results suggest that nafamostat mesilate may have a potential therapeutic role for neuroprotection against focal cerebral ischemia through thrombin inhibition.

Chen, Tao; Wang, Jing; Li, Chenhui; Zhang, Weining; Zhang, Luyong; An, Lufan; Pang, Tao; Shi, Xinzhong; Liao, Hong

2014-01-01

253

Liquid crystal-based detection of thrombin coupled to interactions between a polyelectrolyte and a phospholipid monolayer.  

Science.gov (United States)

Herein, we describe a real-time, label-free biosensing strategy for thrombin detection that uses the orientational properties of nematic liquid crystals (LCs) and the interactions between a polyelectrolyte and a phospholipid monolayer. The imaging principle is based on the disruption of the orientation of 4-cyano-4'-pentylbiphenyl by reorganized 1,2-dioleoyl-sn-glycero-3-phospho-rac-(1-glycerol) sodium salt (DOPG) at the aqueous/LC interface. Positively charged, multiple arginine peptides (poly-l-arginine hydrochloride) interacted with negatively charged DOPG at the aqueous/LC interface, which caused reorganization of the phospholipid layer and induced an orientational transition of LCs from a homeotropic to a planar state. As a result, a dark to bright shift in the optical response was observed. Thrombin cleaves poly-l-arginine hydrochloride into peptides. Thus, when thrombin was added, the optical signals generated by the LCs reverted from bright to dark because of the weakened ability of the fragments to induce electrostatic interactions. The limit of detection of the LC-based sensor was 0.25ng/mL (6.7pM) thrombin, and the sensor was fully reusable. The detection limit of our LC-based interface sensor is 600 times lower than that of a previously reported enzyme-linked aptamer assay for the detection of thrombin. Thus, we have established a new, simple thrombin biosensor with high sensitivity and low interference. PMID:24708935

Zhang, Minmin; Jang, Chang-Hyun

2014-06-15

254

GIT1 mediates thrombin signaling in endothelial cells: role in turnover of RhoA-type focal adhesions.  

Science.gov (United States)

Thrombin mediates changes in endothelial barrier function and increases endothelial permeability. A feature of thrombin-enhanced endothelial hyperpermeability is contraction of endothelial cells (ECs), accompanied by formation of focal adhesions (FAs). Recently, a G protein-coupled receptor kinase-interacting protein, GIT1, was shown to regulate FA disassembly. We hypothesized that GIT1 modulates thrombin-induced changes in FAs. In human umbilical vein ECs (HUVECs), thrombin recruited GIT1 to FAs, where GIT1 colocalized with FAK and vinculin. Recruitment of GIT1 to FAs was dependent on activation of the small GTPase RhoA, and Rho kinase, as demonstrated by adenoviral transfection of dominant-negative RhoA and treatment with Y-27632. Thrombin stimulated GIT1 tyrosine phosphorylation with a time course similar to FAK phosphorylation in a Rho kinase- and Src-dependent manner. Depletion of GIT1 with antisense GIT1 oligonucleotides had no effect on basal cell morphology, but increased cell rounding and contraction of HUVECs, increased FA formation, and increased FAK tyrosine phosphorylation in response to thrombin, concomitant with increased endothelial hyperpermeability. These data identify GIT1 as a novel mediator in agonist-dependent signaling in ECs, demonstrate that GIT1 is involved in cell shape changes, and suggest a role for GIT1 as a negative feedback regulator that augments recovery of cell contraction. PMID:15016733

van Nieuw Amerongen, Geerten P; Natarajan, Kanchana; Yin, Guoyong; Hoefen, Ryan J; Osawa, M; Haendeler, Judith; Ridley, A J; Fujiwara, K; van Hinsbergh, Victor W M; Berk, Bradford C

2004-04-30

255

Surface Induced Self-Assembly of Fibrinogen Fibers in the Absence of Thrombin  

Science.gov (United States)

Wound healing is a complex process imitated by the formation of fibrin fibers that are involved in clot formation and fibroblast migration. Normally this process is triggered by thrombin cleavage of the E domain on the fibrinogen molecules, which allows them to spontaneously self-assemble into the fibers. Here we demonstrate that this process can also be initiated in the absence of thrombin. We show that by simply placing the proteins in contact with hydrocarbon functionalized clay surfaces, molecular reorientation occurs which allows fibers to form from the intact fibrinogen protein. Furthermore, using monoclonal antibodies, we determined which regions on the ?C domains are involved in the formation of the new fibrinogen fibers. This allowed us to extend these findings to general hydrophobic surfaces, such as those presented by most hydrocarbon polymers. On the other hand, the carboxyl terminal part of the A? chain, can interact with amine containing polymers, and suppress formation of the fibers.

Koo, Jaseung; Rafailovich, Miriam; Galanakis, Dennis

2009-03-01

256

Effects of the oral, direct thrombin inhibitor dabigatran on five common coagulation assays  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Dabigatran is an oral, reversible thrombin inhibitor that has shown promising results in large clinical trials. Laboratory monitoring is not needed but the effects on common coagulation assays are incompletely known. Dabigatran was added to plasma from healthy subjects in the concentration range 0-1,000 mu g/l and analysed using several reagents for activated thromboplastin time (APTT), prothrombin time (PT), fibrinogen, antithrombin, and activated protein C resistance. Typical trough concent...

Lindahl, Tomas; Baghaei, Fariba; Fagerberg Blixter, Inger; Gustafsson, Kerstin; Stigendal, Lennart; Sten-linder, Margareta; Strandberg, Karin; Hillarp, Andreas

2011-01-01

257

Permeability of Three-Dimensional Fibrin Constructs Corresponds to Fibrinogen and Thrombin Concentrations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Research in the last few years have focused on the use of three-dimensional (3D) fibrin construct to deliver growth factors and cells. Three-dimensional construct permeability and porosity are important aspects for proper nutrient uptake, gas exchange, and waste removal—factors that are critical for cell growth and survival. We have previously reported that the mechanical strength (stiffness) of 3D fibrin constructs is dependent on the fibrinogen and thrombin concentration. In this study, w...

2012-01-01

258

Thrombin Stimulates Human Endothelial Arginase Enzymatic Activity via RhoA/ROCK Pathway  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background— Arginase competes with endothelial nitric oxide synthase (eNOS) for the substrate L-arginine and decreases NO production. This study investigated regulatory mechanisms of arginase activity in endothelial cells and its role in atherosclerosis. Methods and Results— In human endothelial cells isolated from umbilical veins, thrombin concentration- and time-dependently stimulated arginase enzymatic activity, reaching a 1.9-fold increase (P<0.001) at 1 U/mL for 24 hours. The effect...

Ming, Xiu-fen; Barandier, Christine; Viswambharan, Hema; Kwak, Brenda R.; Mach, Franc?ois; Mazzolai, Lucia; Hayoz, Daniel; Ruffieux, Jean; Rusconi, Sandro; Montani, Jean-pierre; Yang, Zhihong

2005-01-01

259

Rac inhibits thrombin-induced Rho activation: evidence of a Pak-dependent GTPase crosstalk  

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The strict spatio-temporal control of Rho GTPases is critical for many cellular functions, including cell motility, contractility, and growth. In this regard, the prototypical Rho family GTPases, Rho, Rac, and Cdc42 regulate the activity of each other by a still poorly understood mechanism. Indeed, we found that constitutively active forms of Rac inhibit stress fiber formation and Rho stimulation by thrombin. Surprisingly, a mutant of Rac that is unable to activate Pak1 failed to inhibit thro...

Rosenfeldt, Hans; Castellone, Maria Domenica; Randazzo, Paul A.; Gutkind, J. Silvio

2006-01-01

260

The G protein ?? subunit mediates reannealing of adherens junctions to reverse endothelial permeability increase by thrombin  

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The inflammatory mediator thrombin proteolytically activates protease-activated receptor (PAR1) eliciting a transient, but reversible increase in vascular permeability. PAR1-induced dissociation of G? subunit from heterotrimeric Gq and G12/G13 proteins is known to signal the increase in endothelial permeability. However, the role of released G?? is unknown. We now show that impairment of G?? function does not affect the permeability increase induced by PAR1, but prevents reannealing of a...

Knezevic, Nebojsa; Tauseef, Mohammad; Thennes, Tracy; Mehta, Dolly

2009-01-01

 
 
 
 
261

Postpyelolithotomy Renal Artery Pseudoaneurysm Management with Percutaneous Thrombin Injection: A Case Report  

International Nuclear Information System (INIS)

Renal artery pseudoaneurysm leading to life-threatening hematuria can occur after a surgical procedure such as pyelolithotomy, albeit rarely. With recent advances in transarterial embolization techniques, this minimally invasive procedure has become the treatment of choice, replacing surgery. We present a case of massive hematuria due to renal artery pseudoaneurysm developing after pyelolithotomy that was managed with percutaneus thrombin injection directly into the pseudoaneurysm

2008-03-01

262

Ultrasound guided percutaneous thrombin injection for the treatment of iatrogenic pseudoaneurysms  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Iatrogenic aneurysms are usually postcatheterisation pseudoaneurysms of the femoral artery. Until recently, the treatment of choice was ultrasound guided compression repair. A case of pseudoaneurysm of the axillary artery, arising as a complication of pacemaker insertion in an 83 year old man is reported. Compression repair was not possible in this case, and so the aneurysm was occluded by percutaneous ultrasound guided thrombin injection directly into the aneurysm sac. Percutaneous ultrasou...

1999-01-01

263

Coil embolization of inferior epigastric artery pseudoaneurysm after percutaneous thrombin injection failure: a case report  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We report a case of a 71-year old woman with right inferior epigastric artery pseudoaneurysm following laceration by a computed tomography-guided 18G biopsy needle. The laceration was initially treated with placement of retained sutures; however the patient turned hemodynamically unstable 41 days later. Percutaneous ultrasound-guided injection of 1500 U of thrombin solution resulted in almost complete thrombosis of the pseudoaneurysm; however 24 hour control ultrasound revealed refilling of t...

2009-01-01

264

Reduced thrombin generation increases host susceptibility to group A streptococcal infection  

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Bacterial plasminogen activators are commonplace among microbial pathogens, implying a central role of host plasmin in supporting bacterial virulence. Group A streptococci (GAS) secrete streptokinase, a specific activator of human plasminogen (PLG). The critical contribution of the streptokinase-PLG interaction to GAS pathogenicity was recently demonstrated using mice expressing human PLG. To examine the importance of thrombin generation in antimicrobial host defense, we challenged mice with ...

Sun, Hongmin; Wang, Xixi; Degen, Jay L.; Ginsburg, David

2009-01-01

265

An Integrated Mathematical Model of Thrombin-, Histamine-and VEGF-Mediated Signalling in Endothelial Permeability  

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Background: Endothelial permeability is involved in injury, inflammation, diabetes and cancer. It is partly regulated by the thrombin-, histamine-, and VEGF-mediated myosin-light-chain (MLC) activation pathways. While these pathways have been investigated, questions such as temporal effects and the dynamics of multi-mediator regulation remain to be fully studied. Mathematical modeling of these pathways facilitates such studies. Based on the published ordinary differential equation models of t...

2011-01-01

266

Thrombin Production and Human Neutrophil Elastase Sequestration by Modified Cellulosic Dressings and Their Electrokinetic Analysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Wound healing is a complex series of biochemical and cellular events. Optimally, functional material design addresses the overlapping acute and inflammatory stages of wound healing based on molecular, cellular, and bio-compatibility issues. In this paper the issues addressed are uncontrolled hemostasis and inflammation which can interfere with the orderly flow of wound healing. In this regard, we review the serine proteases thrombin and elastase relative to dressing functionality that improve...

Judson Vincent Edwards; Nicolette Prevost

2011-01-01

267

Quantum and Molecular Dynamics Study for Binding of Macrocyclic Inhibitors to Human ?-Thrombin  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Molecular dynamics simulations followed by quantum mechanical calculation and Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) analysis have been carried out to study binding of proline- and pyrazinone-based macrocyclic inhibitors (L86 and T76) to human ?-thrombin. Detailed binding interaction energies between these inhibitors and individual protein fragments are calculated using DFT method based on a new quantum mechanical approach for computing protein-ligand interaction energy...

Wu, Emilia L.; Mei, Ye; Han, Keli; Zhang, John Z. H.

2007-01-01

268

The direct thrombin inhibitor argatroban: a review of its use in patients with and without HIT  

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Argatroban is a synthetic direct thrombin inhibitor with a relative short elimination half-life of 45 minutes and elimination which is predominantly performed via hepatic metabolism. Argatroban anticoagulation has been systematically studied in patients exhibiting the heparin-induced thrombocytopenia (HIT)/thrombosis syndrome and demonstrated to be a safe and effective therapy in this indication. Moreover, in smaller studies argatroban has also been assessed in special clinical settings in no...

2007-01-01

269

Thrombin and TNF-?/IL-1? Synergistically Induce Fibroblast-Mediated Collagen Gel Degradation  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Degradation of preexisting and newly synthesized extracellular matrix is thought to play an important role in tissue remodeling. The current study evaluated whether thrombin and TNF-?/IL-1? could collaboratively induce collagen degradation by human fetal lung fibroblasts (HFL-1) and adult bronchial fibroblasts cultured in three-dimensional collagen gels. TNF-?/IL-1? alone induced production of matrix metalloproteinases (MMPs)-1, -3, and -9, which were released in latent form. With the add...

Fang, Qiuhong; Liu, Xiangde; Al-mugotir, Mona; Kobayashi, Tetsu; Abe, Shinji; Kohyama, Tadashi; Rennard, Stephen I.

2006-01-01

270

Studies of thrombin-induced proteoglycan release in the degradation of human and bovine cartilage.  

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Because fibrin is commonly observed within arthritic joints, studies were undertaken to determine whether purified coagulation and fibrinolytic proteases degrade cartilage in vitro and to seek evidence for the activation of coagulation in arthritic joints through measurements of the levels of inhibitor-enzyme complexes and several other proteins associated with coagulation and fibrinolysis. The concentrations of 13 plasma proteins and complexes of thrombin and Factor Xa with antithrombin III ...

Furmaniak-kazmierczak, E.; Cooke, T. D.; Manuel, R.; Scudamore, A.; Hoogendorn, H.; Giles, A. R.; Nesheim, M.

1994-01-01

271

Thrombin-targeted liposomes establish a sustained localized anticlotting barrier against acute thrombosis.  

Science.gov (United States)

The goal of the present work was to design and test an acute-use nanoparticle-based antithrombotic agent that exhibits sustained local inhibition of thrombin without requiring a systemic anticoagulant effect to function against acute arterial thrombosis. To demonstrate proof of concept, we functionalized the surface of liposomes with multiple copies of the direct thrombin inhibitor, d-phenylalanyl-l-prolyl-l-arginyl-chloromethyl ketone (PPACK), which exhibits high affinity for thrombin as a free agent but manifests too rapid clearance in vivo to be effective alone. The PPACK-liposomes were formulated as single unilamellar vesicles, with a diameter of 170.78 ± 10.59 nm and a near neutral charge. In vitro models confirmed the inhibitory activity of PPACK-liposomes, demonstrating a KI' of 172.6 nM. In experimental clots in vitro, treatment of formed clots completely abrogated any further clotting upon exposure to human plasma. The liposomes were evaluated in vivo in a model of photochemical-induced carotid artery injury, resulting in significantly prolonged arterial occlusion time over that of controls (69.06 ± 5.65 min for saline treatment, N = 6, 71.33 ± 9.46 min for free PPACK treated; N = 4, 85.75 ± 18.24 min for precursor liposomes; N = 4, 139.75 ± 20.46 min for PPACK-liposomes; P = 0.0049, N = 6). Systemic anticoagulant profiles revealed a rapid return to control levels within 50 min, while still maintaining antithrombin activity at the injury site. The establishment of a potent and long-acting anticoagulant surface over a newly forming clot with the use of thrombin targeted nanoparticles that do not require systemic anticoagulation to be effective offers an alternative site-targeted approach to the management of acute thrombosis. PMID:24063304

Palekar, Rohun U; Myerson, Jacob W; Schlesinger, Paul H; Sadler, J Evan; Pan, Hua; Wickline, Samuel A

2013-11-01

272

The Emerging Role of the Thrombin Receptor (PAR-1) in Melanoma Metastasis - a Possible Therapeutic Target  

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Melanoma remains as the deadliest form of skin cancer with limited and inefficient treatment options available for patients with metastatic disease. Within the last decade, the thrombin receptor, Protease Activated Receptor-1, has been described as an essential gene involved in the progression of human melanoma. PAR-1 is known to activate adhesive, invasive and angiogenic factors to promote melanoma metastasis. It is overexpressed not only in metastatic melanoma cell lines but is also highly ...

2011-01-01

273

Successful endovascular treatment of a hemodialysis graft pseudoaneurysm by covered stent and direct percutaneous thrombin injection.  

LENUS (Irish Health Repository)

Vascular access for hemodialysis remains a challenge for nephrologists, vascular surgeons, and interventional radiologists alike. Arteriovenous fistula and synthetic grafts remain the access of choice for long-term hemodialysis; however, they are subject to complications from infection and repeated needle cannulation. Pseudoaneurysms are an increasingly recognized adverse event. At present, there are many minimally invasive methods to repair these wall defects. We present a graft pseudoaneurysm, which required a combination of endovascular stent graft placement and percutaneous thrombin injection for successful occlusion.

Keeling, Aoife N

2011-07-25

274

Intraovarian Thrombin and Activated Protein C Signaling System Regulates Steroidogenesis during the Periovulatory Period  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In addition to its role in blood coagulation, thrombin directly stimulates protease-activated receptors (PAR) or interacts with thrombomodulin (THBD) to activate membrane-bound protein C which stimulates PAR1 and PAR4 receptors to promote downstream pleiotropic effects. Our DNA microarray, RT-PCR, and immunostaining analyses demonstrated ovarian expression of THBD, activated protein C (APC) receptor [endothelial protein C receptor (EPCR)], as well as PAR1 and PAR4 receptors in mice. After tre...

Cheng, Yuan; Kawamura, Kazuhiro; Deguchi, Masashi; Takae, Seido; Mulders, Sabine M.; Hsueh, Aaron J. W.

2012-01-01

275

Electrochemiluminescence biosensor based on CdSe quantum dots for the detection of thrombin  

International Nuclear Information System (INIS)

A novel QDs electrochemiluminescence (ECL) biosensor for the determination of thrombin was described. The CdSe QDs solution was dripped onto the clear surface of the ITO and then immersed in PBS which contained EDC and NHS as a coupling agent to activate the carboxyl-terminated surface of the CdSe QDs. The ITO electrode was immersed in the PBS containing 0.4 ?M aptamer, followed by rinsing with PBS and dried with N2 again, then dipped in the BSA solution for 30 min to decrease the non-specific binding. After that, the aptamer modified ITO was soaked in PBS to remove unbound aptamer. Under optimal conditions, the linear range was obtained from 0 to 64 ?g mL?1 with a correlation coefficient of 0.9986 (n = 16). The control experiment was also carried out by using BSA, lysozyme and IgG in the absence of thrombin. The results showed that the aptasensor had good specificity, stability and reproducibility to the thrombin. Moreover, the aptasensor could be used for detection of real sample with consistent results in comparison with those obtained by electrochemical method which could provide a promising platform for fabrication of aptamer based biosensors.

2012-03-30

276

Posttraumatic lingual artery pseudoaneurysm treated with ultrasound-guided percutaneous thrombin injection.  

Science.gov (United States)

Pseudoaneurysms of the lingual artery are extremely rare and are commonly iatrogenic in nature or less frequently a result of blunt or penetrating trauma. Traditionally, these vascular abnormalities have been repaired with open or endovascular techniques. Although ultrasound-guided percutaneous thrombin injection has become a standard treatment for superficial pseudoaneurysms, there are no reports of this being used in the treatment of lingual artery pseudoaneurysms. We report the case of a 26-year-old man who suffered a penetrating head and neck injury after an improvised explosive device blast in Iraq who presented with persistent oropharyngeal swelling. Color-flow Doppler ultrasonography revealed the classic yin/yang sign of a pseudoaneurysm, and a computed tomography scan was obtained that revealed a right lingual artery pseudoaneurysm. With the lack of endovascular capabilities and the excessive risk of open surgery, thrombin was injected directly into the pseudoaneurysm under ultrasound guidance. A computed tomography scan and Doppler ultrasonography revealed complete resolution of the aneurysm. This article presents the first reported case in the English literature of a lingual artery aneurysm after penetrating trauma managed successfully with ultrasound-guided percutaneous thrombin injection. PMID:24365080

Masella, Pamela C; Hanson, Megan M; Hall, Brian T; Verghese, John J; Kellicut, Dwight C

2014-07-01

277

Percutaneous Ablation of Peripheral Pseudoaneurysms Using Thrombin: A Simple and Effective Solution  

International Nuclear Information System (INIS)

Purpose: To assess the effectiveness of tissue adhesive and thrombin solution in the percutaneous ablation of peripheral artery pseudoaneurysms.Methods: Twenty-five pseudoaneurysms were treated over a 33-month period; all had failed ultrasound-guided compression. Tissue adhesive or thrombin solution was injected percutaneously, with needle tip position and changes within the aneurysm confirmed with color Doppler ultrasound. In 19 cases we utilized a protective balloon inflated across the aneurysm neck prior to the injection of tissue adhesive and in six cases used thrombin injection alone. Seven patients were anticoagulated. Patients were followed up after the procedure.Results: All 25 aneurysms were treated successfully; two patients required a return visit and there were no immediate complications or peripheral emboli detected. One patient developed a contralateral pseudoaneurysm.Conclusions: The percutaneous injection of pseudoaneurysms is a safe, atraumatic, and effective treatment for femoral artery pseudoaneurysms in the peripheral circulation. There are significant advantages over ultrasound-guided compression or surgical repair

2000-11-01

278

Percutaneous Ablation of Peripheral Pseudoaneurysms Using Thrombin: A Simple and Effective Solution  

International Nuclear Information System (INIS)

Purpose: To assess the effectiveness of tissue adhesive and thrombin solution in the percutaneous ablation of peripheral artery pseudoaneurysms.Methods: Twenty-five pseudoaneurysms were treated over a 33-month period; all had failed ultrasound-guided compression. Tissue adhesive or thrombin solution was injected percutaneously, with needle tip position and changes within the aneurysm confirmed with color Doppler ultrasound. In 19 cases we utilized a protective balloon inflated across the aneurysm neck prior to the injection of tissue adhesive and in six cases used thrombin injection alone. Seven patients were anticoagulated. Patients were followed up after the procedure.Results: All 25 aneurysms were treated successfully; two patients required a return visit and there were no immediate complications or peripheral emboli detected. One patient developed a contralateral pseudoaneurysm.Conclusions: The percutaneous injection of pseudoaneurysms is a safe, a traumatic, and effective treatment for femoral artery pseudoaneurysms in the peripheral circulation. There are significant advantages over ultrasound-guided compression or surgical repair

2000-11-01

279

Doppler ultrasound-guided percutaneous thrombin injection for treating femoral pseudoaneurysms  

Directory of Open Access Journals (Sweden)

Full Text Available Objective: To evaluate the success rate of percutaneous injectionof thrombin, guided by Doppler ultrasound to treat femoralpseudoaneurysms. Methods: Twenty-three patients withfemoral pseudoaneurysms were treated with ultrasound-guidedthrombin injection, between September 2003 and October 2007.Pseudoaneurysm size, dose of thrombin used, result of therapy andcomplications were prospectively documented. Other aspects analyzedincluded the type of procedure that caused the pseudoaneurysm(diagnostic catheterization, angioplasty, stent placement, size ofendovascular introducer, use of hemostatic device and body massindex (BMI of patients. Results: A total of 27 injections of thrombinwere performed. The mean transverse diameter was 3.5 cm. Themean dose of thrombin injected was 666.7 IU. The primary successrate ranged from 19 to 23 (83%. Reperfusion occurred in onepseudoaneurysm. The rate of secondary thrombosis was four in four(100%. No thromboembolic, infectious or allergic complicationsoccurred. Conclusions: Ultrasound-guided percutaneous thrombininjection is the best method for treating femoral pseudoaneurysmscaused by endovascular procedures. It presents high rates of success,low recurrence rates and almost no complications.

Frederico Celestino Miranda

2008-12-01

280

Treatment of Iatrogenic femoral artery pseudoaneurysms using ultrasound-guided injection of thrombin  

International Nuclear Information System (INIS)

AIM: To evaluate the use of ultrasound-guided percutaneous injection of thrombin for treatment of femoral artery pseudoaneurysms. METHOD: Nine patients with a confirmed femoral false aneurysm were included in the study. 0.5-1 ml of a 2000 U/ml solution of activated bovine thrombin was injected under ultrasound visualization into the neck of the aneurysm to induce thrombosis. The parent artery and adjacent major vessels were checked during and after the procedure to exclude propagation of thrombus. A check ultrasound examination was undertaken on the following day. RESULTS: Eight patients were successfully treated by a single injection. One patient required a second injection due to recurrence of their pseudoaneurysm 4 days after the initial treatment. The procedure was well tolerated in all cases and no complications were encountered. CONCLUSION: This small series provides further evidence that ultrasound-guided thrombin injection is a promising new method for the treatment of femoral false aneurysms. Hughes, M.J. et al. (2000)

2000-10-01

 
 
 
 
281

Mutant N143P Reveals How Na[superscript +] Activates Thrombin  

Energy Technology Data Exchange (ETDEWEB)

The molecular mechanism of thrombin activation by Na{sup +} remains elusive. Its kinetic formulation requires extension of the classical Botts-Morales theory for the action of a modifier on an enzyme to correctly account for the contribution of the E*, E, and E:Na{sup +} forms. The extended scheme establishes that analysis of k{sub cat} unequivocally identifies allosteric transduction of Na{sup +} binding into enhanced catalytic activity. The thrombin mutant N143P features no Na{sup +}-dependent enhancement of k{sub cat} yet binds Na{sup +} with an affinity comparable to that of wild type. Crystal structures of the mutant in the presence and absence of Na{sup +} confirm that Pro{sup 143} abrogates the important H-bond between the backbone N atom of residue 143 and the carbonyl O atom of Glu{sup 192}, which in turn controls the orientation of the Glu{sup 192}-Gly{sup 193} peptide bond and the correct architecture of the oxyanion hole. We conclude that Na{sup +} activates thrombin by securing the correct orientation of the Glu{sup 192}-Gly{sup 193} peptide bond, which is likely flipped in the absence of cation. Absolute conservation of the 143-192 H-bond in trypsin-like proteases and the importance of the oxyanion hole in protease function suggest that this mechanism of Na{sup +} activation is present in all Na{sup +}-activated trypsin-like proteases.

Niu, Weiling; Chen, Zhiwei; Bush-Pelc, Leslie A.; Bah, Alaji; Gandhi, Prafull S.; Di Cera, Enrico; (WU-MED)

2010-01-12

282

Does thrombin stimulation of human platelets proceed via a simultaneous Na"+-H"+ exchange?  

International Nuclear Information System (INIS)

Thrombin stimulation of human platelets initiates a membrane depolarization attributable to a Na"+ influx into, and an alkalinization of, the cytoplasm, both of which follow a similar rapid time scale and thrombin dose dependence. These responses precede secretion of the contents of dense granules (serotonin) and, after 1 min, of lysosomes (?-glucuronidase). These markers have been used to determine whether the Na"+ influx and H"+ efflux are sequential or simultaneous. They have examined these parameters in D_2O-Hepes buffers. NMR evidence indicates that equilibration is rapid, and virtually complete within the 3 minute pre-stimulation platelets equilibration period. The rate of depolarization is 70-80% slower in D_2O than in H_2O. The time to reach maximal depolarization is 5-10 sec longer, the extent of depolarization 60% inhibited, and the [H"+] change 85-100% inhibited. The serotonin secretion is unaltered, and the ?-glucuronidase secretion is 130-180% enhanced. 10"-"4 M amiloride inhibits Na"+ influx, i.e. depolarization, and the pH change completely. Adjustment to pH/sub i/ 7.3 with NH_4Cl led to a 30-80% enhanced ?-glucuronidase release upon thrombin exposure. These results suggest that the Na"+ and H"+ fluxes across the platelet membrane occur sequentially, the Na"+ occurring first. Furthermore, granule secretion, previously shown by us to be independent of the existent Na"+ gradient, depends on the cytoplasmic K"+ and H"+ concentrations

1986-03-05

283

The membrane potential modulates thrombin-stimulated Ca²? mobilization and platelet aggregation.  

Science.gov (United States)

G protein-coupled receptors can be directly modulated by changes in transmembrane voltage in a variety of cell types. Here we show that, while changes in the membrane voltage itself do not induce detectable modifications in the cytosolic Ca(2+) concentration, platelet stimulation with thrombin or the PAR-1 and PAR-4 agonist peptides SFLLRN and AYPGKF, respectively, results in Ca(2+) release from intracellular stores that is sensitive to the membrane depolarisation. Direct activation of G proteins or phospholipase C by AlF4(-) and m-3M3FBS, respectively, leads to Ca(2+) release that is insensitive to changes in the membrane potential. Thapsigargin-, as well as OAG-induced Ca(2+) entry are affected by the membrane voltage, probably as a result of the modification in the driving force for Ca(2+) influx; however, hyperpolarisation does not enhance thrombin- or OAG-evoked Ca(2+) entry probably revealing the presence of a voltage-sensitive regulatory mechanism. Transmembrane voltage also modulates the activity of the plasma membrane Ca(2+)-ATPase (PMCA) most likely due to a decrease in the phosphotyrosine content of the pump. Thrombin-stimulated platelet aggregation is modulated by membrane depolarisation by a mechanism that is, at least partially, independent of Ca(2+). These observations indicate that PAR-1 and PAR-4 receptors are modulated by the membrane voltage in human platelets. PMID:23988350

Albarrán, Letizia; Dionisio, Natalia; López, Esther; Salido, Ginés M; Rosado, Juan A

2013-10-15

284

Novel modular DNA aptamer for human thrombin with high anticoagulant activity.  

Science.gov (United States)

Aptamers based on nucleic acids are a promising alternative to antibodies in therapy and diagnostics. Several DNA aptamers against human thrombin have been developed by selection from random libraries: a 15-mer and its derivatives, a 29-mer, and a 31-mer. Some of them are patented and already under clinical trial. The 15-mer structure was determined by X-ray and NMR and turned out to be a monomolecular antiparallel G-quadruplex. The other aptamers mentioned above have higher inhibitory activity than the initial 15-mer, but there are not yet structural data explaining this phenomenon. Here, the initial 15-mer, 31-mer, and novel RA-36 aptamers are compared to establish the structure-function correlation, providing a solid ground for further rational aptameric drug design. For the molecular dynamic simulation of aptamers, the force field parmbsc0 was ported onto GROMACS, and the main stabilizing parameters were revealed, leading to the novel DNA aptamer RA-36. The functional properties of the DNA aptamers were studied by conventional coagulation tests, which do not directly elucidate the mechanism of thrombin inhibition by aptamers. Improved turbidimetric measurements provided data to develop detailed kinetics showing that the 31-mer and RA-36, in contrast to the 15-mer, are competitive inhibitors. These data revealed RA-36 to be an efficient thrombin inhibitor with a dose-dependent effect. Animal tests of the studied DNA aptamers suggested an unexpected species-specificity of the novel RA-36. PMID:21728967

Zavyalova, E; Golovin, A; Reshetnikov, R; Mudrik, N; Panteleyev, D; Pavlova, G; Kopylov, A

2011-01-01

285

Comparison of laser-activated tissue solders and thrombin-activated cryoprecipitate for wound closure  

Science.gov (United States)

To determine the relative strengths of various biologic adhesives at several timepoints, we compared thrombin-activated SD (solvent-detergent treated) cryoprecipitate with laser- activated SD cryoprecipitate and a laser-activated, albumin-based glue. Male Sprague-Dawley rats (n equals 79) received four, 3-cm, dorsal skin incisions which were closed with either laser- activated cryoprecipitate, laser-activated albumin solder, thrombin-activated cryoprecipitate, or standard skin staples. The cryoprecipitate was derived from pooled human plasma and was treated with a solvent-detergent process, rendering it free of envelope-coated viruses (i.e., HBV, HIV). An 808-nm diode laser was used to activate each solder with an average duration of exposure of 75 seconds per incision. Animals were sacrificed for evaluation of wound tensile strength and histology at 0 hours, 2 hours, 4 hours, and 4 days. At all timepoints tested, laser-activated solders were significantly stronger than thrombin-activated cryoprecipitate (p < 0.03) and control wounds (p < 0.003). There was no significant difference in tensile strength between the two types of laser-activated solder at any timepoint.

Kayton, Mark L.; Libutti, Steven K.; Bessler, Marc; Allendorf, John D. F.; Eiref, Simon D.; Marx, Gerard; Mou, Xiaode; Morales, Alfredo M.; Treat, Michael R.; Nowygrod, Roman

1994-09-01

286

Isolation and characterization of the thrombin-like enzyme from Cryptelytrops purpureomaculatus venom.  

Science.gov (United States)

A thrombin-like enzyme, purpurase, was purified from the Cryptelytrops purpureomaculatus (mangrove pit viper) venom using high performance ion-exchange and gel filtration chromatography. The purified sample (termed purpurase) yielded a homogeneous band in SDS-polyacrylamide gel electrophoresis with a molecular weight of 35,000. The N-terminal sequence of purpurase was determined to be VVGGDECNINDHRSLVRIF and is homologous to many other venom thrombin-like enzymes. Purpurase exhibits both arginine ester hydrolase and amidase activities. Kinetic studies using tripeptide chromogenic anilide substrates showed that purpurase is not fastidious towards its substrate. The clotting times of fibrinogen by purpurase were concentration dependent, with optimum clotting activity at 3mg fibronogen/mL. The clotting activity by purpurase was in the following decreasing order: cat fibrinogen>human fibrinogen>dog fibrinogen>goat fibrinogen>rabbit fibrinogen. Reversed-phase HPLC analysis of the products of action of purpurase on bovine fibrinogen showed that only fibrinopeptide A was released. Indirect ELISA studies showed that anti-purpurase cross-reacted strongly with venoms of most crotalid venoms, indicating the snake venom thrombin-like enzymes generally possess similar epitopes. In the more specific double-sandwich ELISA, however, anti-purpurase cross-reacted only with venoms of certain species of the Trimeresurus complex, and the results support the recent proposed taxonomy changes concerning the Trimeresurus complex. PMID:19770070

Tan, Nget Hong

2010-01-01

287

Heparin cofactor II-thrombin complex: a biomarker of MPS disease.  

Science.gov (United States)

The mucopolysaccharidoses are a group of lysosomal storage disorders caused by defects in the degradation of glycosaminoglycans. Each disorder is characterized by progressive multi-system disease with considerable clinical heterogeneity. The clinical heterogeneity of these disorders is thought to be related to the degree of the metabolic block in glycosaminoglycan degradation which in turn is related to the underlying mutation at the respective locus. There are currently no objective means other than longitudinal clinical observation, or the detection of a recurrent genetic mutation to accurately predict the clinical course for an individual patient, particularly when diagnosed early. In addition, there are no specific disease biomarkers that reflect the total body burden of disease. The lack of specific biomarkers has made monitoring treatment responses and predicting disease course difficult in these disorders. The recent introduction of enzyme replacement therapy for MPS I, II, and VI highlights the need for objective measures of disease burden and disease responsiveness. We show that serum levels of heparin cofactor II-thrombin complex is a reliable biomarker of the mucopolysaccharidoses. Untreated patients have serum levels that range from 3- to 112-fold above control values. In a series of patients with varying severity of mucopolysaccharidosis I, the serum complex concentration was reflective of disease severity. In addition, serum heparin cofactor II-thrombin levels showed responsiveness to various treatment regimens. We propose that serum levels of heparin cofactor II-thrombin complex may provide an important assessment and monitoring tool for patients with mucopolysaccharidosis. PMID:18511319

Randall, Derrick R; Colobong, Karen E; Hemmelgarn, Harmony; Sinclair, Graham B; Hetty, Elly; Thomas, Anita; Bodamer, Olaf A; Volkmar, Barbara; Fernhoff, Paul M; Casey, Robin; Chan, Alicia K; Mitchell, Grant; Stockler, Silvia; Melancon, Serge; Rupar, Tony; Clarke, Lorne A

2008-08-01

288

Topics in Operator Theory  

CERN Document Server

This is the first volume of a collection of original and review articles on recent advances and new directions in a multifaceted and interconnected area of mathematics and its applications. It encompasses many topics in theoretical developments in operator theory and its diverse applications in applied mathematics, physics, engineering, and other disciplines. The purpose is to bring in one volume many important original results of cutting edge research as well as authoritative review of recent achievements, challenges, and future directions in the area of operator theory and its applications.

Ball, Joseph A; Helton, JWilliam; Rodman, Leiba; Spitkovsky, Iiya

2010-01-01

289

Topics in circular statistics  

CERN Document Server

This research monograph on circular data analysis covers some recent advances in the field, besides providing a brief introduction to, and a review of, existing methods and models. The primary focus is on recent research into topics such as change-point problems, predictive distributions, circular correlation and regression, etc. An important feature of this work is the S-plus subroutines provided for analyzing actual data sets. Coupled with the discussion of new theoretical research, the book should benefit both the researcher and the practitioner. Contents: Circular Probability Distributions

Jammalamadaka, S Rao

2001-01-01

290

Topics in CP violation  

International Nuclear Information System (INIS)

Given the varied backgrounds of the members of this audience this talk will be a grab bag of topics related to the general theme of CP Violation. I do not have time to dwell in detail on any of them. First, for the astronomers and astrophysicists among you, I want to begin by reviewing the experimental status of evidence for CP violation in particle processes. There is only one system where this has been observed, and that is in the decays of neutral K mesons

1992-12-13

291

A ROLE FOR GAB1/SHP2 IN THROMBIN ACTIVATION OF PAK1: GENE TRANSFER OF KINASE-DEAD PAK1 INHIBITS INJURY-INDUCED RESTENOSIS  

Digital Repository Infrastructure Vision for European Research (DRIVER)

To understand the contribution of EGFR transactivation in GPCR agonist-induced signaling events, we have studied the capacity of thrombin in the activation of Gab1-SHP2 in vascular smooth muscle cells (VSMCs). Thrombin activated both Gab1 and SHP2 in a time- and EGFR-dependent manner. Similarly, thrombin induced both Rac1 and Cdc42 activation and these responses were suppressed when either Gab1 or SHP2 stimulation is blocked. Thrombin also induced PAK1 activation in a time- and EGFR-Gab1-SHP2...

Wang, Dong; Paria, Biman C.; Zhang, Qiuhua; Karpurapu, Manjula; Li, Quanyi; Gerthoffer, William T.; Nakaoka, Yoshikazu; Rao, Gadiparthi N.

2009-01-01

292

Investigation of the thrombin-generating capacity, evaluated by thrombogram, and clot formation evaluated by thrombelastography of platelets stored in the blood bank for up to 7 days  

DEFF Research Database (Denmark)

BACKGROUND AND OBJECTIVES: Transfusion based on the Thrombelastograph (TEG) results reduces transfusion requirements in cardiac surgery and in liver transplantation. Taking the pivotal role of thrombin generation in the coagulation process into consideration, the clinical utility of the TEG may, in part, depend on its reflection of the dynamics of thrombin generation. MATERIAL AND METHODS: The kinetics of thrombin generation of platelets stored for 2 and 7 days, respectively, was assessed by calibrated automated thrombogram (CAT) and the lag time (min), time to peak (ttPeak; min), peak (nm thrombin) and endogenous thrombin potential (ETP; nm thrombin*min) were registered. Clot formation was evaluated by TEG and the R time (min), maxial amplitude (MA; mm), time to maximum thrombus generation (TMG; min) and maximum thrombus generation (MTG; dynes cm(-2) s(-1)) and total thrombus generation (TTG; dyne cm(-2)) were registered. RESULTS: Platelets become more procoagulant, evaluated both by TEG and CAT during storage. The reduction in CAT lag time and the ttPeak correlated with a decrease in the TEG R time and TMG (P < 0.0001) as did the CAT peak thrombin generation and the TEG MTG (P = 0.0035). No correlation between ETP and TTG was found (P = 0.65). CONCLUSION: The kinetics of thrombin generation, as evaluated by CAT, correlates with the thrombus generation, as evaluated by thrombelastography and this may in part explain the clinical utility of the TEG in identifying clinically relevant coagulopathies, secondary to impaired thrombin generation Udgivelsesdato: 2008/2

Johansson, Per Ingemar; Svendsen, M.S.

2008-01-01

293

Health Topics: MedlinePlus  

Science.gov (United States)

... features on this page, please enable JavaScript. Health Topics Read about symptoms, causes, treatment and prevention for ... illnesses, health conditions and wellness issues. MedlinePlus health topics are regularly reviewed, and links are updated daily. ...

294

Symbiosis: Rich, Exciting, Neglected Topic  

Science.gov (United States)

Argues that the topic of symbiosis has been greatly neglected and underemphasized in general-biology textbooks. Discusses many types and examples of symbiosis, and provides an extensive bibliography of the literature related to this topic. (JR)

Rowland, Jane Thomas

1974-01-01

295

Topical Acne Treatments and Pregnancy  

Science.gov (United States)

... of medical care and advice from your health care provider. What are topical acne treatments? Topical acne treatments are medications applied directly on the skin that are used in the treatment of acne ...

296

Recombination in radar meteors  

Science.gov (United States)

Recombinations in the ionized columns generated by faint radar meteors are observed as: (1) A rapid loss of returned signal in the first few milliseconds after formation of the column; (2) an apparent absence of bright, low meteors; and (3) anomalies in apparent diffusion rates. Recombination at rates characteristic of dissociative recombination of ionized atmospheric molecules N2(+) and O2(+) is completely consistent with the observations. It appears either that the molecules are ionized in the initial formation of the ionized column or that there is rapid charge exchange. Recombination is a sufficient cause for the differences between diffusion measures and other atmospheric studies.

Southworth, R. B.

1973-01-01

297

Superconcentration and related topics  

CERN Multimedia

A certain curious feature of random objects, introduced by the author as “super concentration,” and two related topics, “chaos” and “multiple valleys,” are highlighted in this book. Although super concentration has established itself as a recognized feature in a number of areas of probability theory in the last twenty years (under a variety of names), the author was the first to discover and explore its connections with chaos and multiple valleys. He achieves a substantial degree of simplification and clarity in the presentation of these findings by using the spectral approach. Understanding the fluctuations of random objects is one of the major goals of probability theory and a whole subfield of probability and analysis, called concentration of measure, is devoted to understanding these fluctuations. This subfield offers a range of tools for computing upper bounds on the orders of fluctuations of very complicated random variables. Usually, concentration of measure is useful when more direct prob...

Chatterjee, Sourav

2014-01-01

298

Topics in orbit equivalence  

CERN Multimedia

This volume provides a self-contained introduction to some topics in orbit equivalence theory, a branch of ergodic theory. The first two chapters focus on hyperfiniteness and amenability. Included here are proofs of Dye's theorem that probability measure-preserving, ergodic actions of the integers are orbit equivalent and of the theorem of Connes-Feldman-Weiss identifying amenability and hyperfiniteness for non-singular equivalence relations. The presentation here is often influenced by descriptive set theory, and Borel and generic analogs of various results are discussed. The final chapter is a detailed account of Gaboriau's recent results on the theory of costs for equivalence relations and groups and its applications to proving rigidity theorems for actions of free groups.

Kechris, Alexander S

2004-01-01

299

Perspective and research topics  

International Nuclear Information System (INIS)

In the preceding chapters various aspects of the theory of turbulent reacting flows are discussed in detail. The fundamental features of such flows, some of the relevant practical problems connected with turbulent combustion, approaches appropriate for the limiting cases of nonpremixed and premixed reactants, and the direct probability-density approach to the description of such flows are treated in successive chapters. There results a relatively complete view of the present status of the fundamental theory and its application to somewhat idealized flows. In this chapter we attempt to provide an overview and perspective of the field and call attention to research topics of greatest interest from both practical and fundamental points of view. (orig.)

1980-01-01

300

Topics on String Phenomenology  

CERN Document Server

These lectures present some topics of string phenomenology and contain two parts. In the first part, I review the possibility of lowering the string scale in the TeV region, that provides a theoretical framework for solving the mass hierarchy problem and unifying all interactions. The apparent weakness of gravity can then be accounted by the existence of large internal dimensions, in the submillimeter region, and transverse to a braneworld where our universe must be confined. I review the main properties of this scenario and its implications for observations at both particle colliders, and in non-accelerator gravity experiments. In the second part, I discuss a simple framework of toroidal string models with magnetized branes, that offers an interesting self-consistent setup for string phenomenology. I will present an algorithm for fixing the geometric parameters of the compactification, build calculable particle physics models such as a supersymmetric SU(5) Grand Unified Theory with three generations of quark...

Antoniadis, Ignatios

2008-01-01

 
 
 
 
301

Role of regulatory exosite I in binding of thrombin to human factor V, factor Va, factor Va subunits, and activation fragments.  

Science.gov (United States)

The blood coagulation proteinase, thrombin, converts factor V into factor Va through a multistep activation pathway that is regulated by interactions with thrombin exosites. Thrombin exosite interactions with human factor V and its activation products were quantitatively characterized in equilibrium binding studies based on fluorescence changes of thrombin covalently labeled with 2-anilinonaphthalene-6-sulfonic acid (ANS) linked to the catalytic site histidine residue by Nalpha-[(acetylthio)acetyl]-D-Phe-Pro-Arg-CH2Cl ([ANS]FPR-thrombin). Exosite I was shown to play a predominant role in the binding of factor V and factor Va from the effect of the exosite I-specific ligand, hirudin54-65, on the interactions. Factor V and factor Va bound to exosite I of [ANS]FPR-thrombin with similar dissociation constants of 3.4 +/- 1.3 and 1.1 +/- 0.4 microM and fluorescence enhancements of 182 +/- 41 and 127 +/- 17%, respectively. Native thrombin and labeled thrombin bound with similar affinity to factor Va. Among factor V activation products, the factor Va heavy chain was shown to contain the site of exosite I binding, whereas exosite I-independent, lower affinity interactions were observed for activation fragments E and C1, and no detectable binding was observed for the factor Va light chain. The results support the conclusion that the factor V activation pathway is initiated by exosite I-mediated binding of thrombin to a site in the heavy chain region of factor V that facilitates the initial cleavage at Arg709 to generate the heavy chain of factor Va. The results further suggest that binding of thrombin through exosite I to factor V activation intermediates may regulate their conversion to factor Va and that similar binding of thrombin to the factor Va produced may reflect a mode of interaction involved in the regulation of prothrombin activation. PMID:10373475

Dharmawardana, K R; Olson, S T; Bock, P E

1999-06-25

302

Effects of thrombin, PAR-1 activating peptide and a PAR-1 antagonist on umbilical artery resistance in vitro  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background The non-thrombotic effects of thrombin in cardiovascular tissues, as mediated via the protease activated receptors (PARs, and particularly PAR-1, have been the focus of much recent research. The aims of this study were to evaluate the effects of thrombin, a specific PAR-1 activating peptide (PAR1-AP, and a PAR-1 antagonist on human umbilical artery tone in vitro. Methods Human umbilical artery samples were obtained from 17 women at term. Arterial rings were suspended under physiologic conditions for isometric recording. The in vitro effects of thrombin (0.5 units/mL to 3 units/mL, PAR1-AP TFLLR-NH2 [10(-9 to 10(-6 M], and PAR-1 antagonist (N-trans cinnamoyl- p-fluoroPhe-p-guanidinoPhe-Leu-Arg-Orn-NH2 [10(-9 M to 10(-5 M] on umbilical artery tone were measured. Results Both thrombin and TFLLR-NH2 exerted a potent cumulative vasodilatory effect on human umbilical artery resistance (P 0.05. Conclusion These findings highlight a potential role for thrombin and PAR-1 receptors in vascular regulation of feto-placental blood flow in normal pregnancy, and in association with the vascular lesions associated with IUGR and pre-eclampsia.

Elliott John T

2005-02-01

303

Apoferritin Protein Nanoparticles Dually labeled with Aptamer and Horseradish Peroxidase as a Sensing Probe for Thrombin Detection  

Energy Technology Data Exchange (ETDEWEB)

A sandwich-type electrochemical aptasensor has been developed for the detection of thrombin, based on dual signal-amplification using HRP and apoferritin. Aptamer1 (Apt1) loaded on core/shell Fe3O4/Au magnetic nanoparticle (AuMNP) was used as recognition elements, and apoferritin dually labeled with Aptamer2 (Apt2) and HRP was used as a detection probe. Sandwich-type complex, Apt1/thrombin/Apt2–apoferritin NPs–HRP was formed by the affinity reactions between AuMNPs–Apt1, thrombin, and Apt2–apoferritin–HRP. The complex was anchored on a screen-printed carbon electrode (SPCE). Differential pulse voltammetry (DPV) was used to monitor the electrode response. The proposed aptasensor yielded a linear current response to thrombin concentrations over a broad range of 0.5 pM to 100 pM with a detection limit of 0.07 pM (S/N = 3). The detection signal was amplified by using apoferritin and HRP. This nanoparticle-based aptasensor offers a new method for rapid, sensitive, selective, and inexpensive quantification of thrombin, and offers a promising potential in biomarker detection and disease diagnosis. --------------------------------------------------------------------------------

Zhao, Jie; Liu, Meiling; Zhang, Youyu; Li, Haitao; Lin, Yuehe; Yao, Shouzhuo

2013-01-08

304

Prolonged duration of type 2 diabetes is associated with increased thrombin generation, prothrombotic fibrin clot phenotype and impaired fibrinolysis.  

Science.gov (United States)

It has been shown that type 2 diabetes (DM) is associated with enhanced thrombin generation and formation of denser fibrin clots of reduced lysability. We sought to investigate the impact of diabetes duration versus glycaemia control on fibrin clot phenotype and its determinants in type 2 diabetic patients. In 156 consecutive Caucasian patients with type 2 diabetes we investigated ex vivo thrombin generation, fibrinolytic proteins, along with plasma fibrin clot permeation (Ks), compaction, turbidity, and efficiency of tissue plasminogen activator (t-PA)-mediated fibrinolysis. Patients with longer diabetes duration (>5 years, median; n=68) had higher peak thrombin generation (+16.3%, p6.5% (48 mmol/mol) (n=77), versus those with HbA1C?6.5% (n=79). Fibrinogen, thrombin-activatable fibrinolysis inhibitor antigen, plasminogen and soluble thrombomodulin were unaffected by disease duration or glycaemia control. Lower clot permeability, longer clot lysis, and higher maximum D-dimer levels released from clots (all p5 years and those with HbA1C>6.5%. We conclude that prolonged duration of type 2 diabetes is associated with increased thrombin formation, hypofibrinolysis, and prothrombotic fibrin clot phenotype. The impact of disease duration on coagulation is different and stronger than that observed during inadequate glycaemia control. PMID:24306139

Konieczynska, Malgorzata; Fil, Korneliusz; Bazanek, Marta; Undas, Anetta

2014-04-01

305

An easy way for the rapid purification of recombinant proteins from Helicobacter pylori using a newly designed expression vector.  

Science.gov (United States)

We constructed a H. pylori expression vector which consisted of both a His-tag and a GST tag as purification tools for recombinant protein and a chloramphenicol resistant cat gene as a reporter. The backbone of the vector pBKcontained an ColEI origin of replication and a kanamycin resistant gene. A set of oligos for the His-tag and the PCR product of gst (glutathione S-transferase) gene were inserted sequentially in frame in themulti-cloning site of pBK. The orf of cat was inserted downstreamof the gst to generate pBKHGC. The 3' part of H. pylori clpB and flaA were cloned into the vector which was introduced into H. pylori. Recombinant proteins were purified by GSH affinity column, digested with thrombin and were analyzed by western blotting. The final recombinant proteins were successfully purified. PMID:24972810

Kang, Hyung-Lyun; Jo, Jin-Sung; Kwon, Soon-Uck; Song, Jae-Young; Seo, Ji-Hyun; Cho, Myung-Je; Baik, Seung-Chul; Youn, Hee-Shang; Rhee, Kwang-Ho; Lee, Woo-Kon

2014-07-01

306

[Timolol topical ophthalmic combination].  

Science.gov (United States)

The primary standard therapy in patients with open-angle glaucoma and ocular hypertension is carried out by means of monotherapy with synthetic prostaglandin analogues. Most of the glaucoma patients need more than one medication for adequate intraocular pressure control. Timolol represents the basic component of these combinations. Timolol topical ophthalmic combinations with dorzolamide (Cosopt), pilocarpine, latanoprost (Xalacom), travoprost and unoprostone are thoroughly described. Most antiglaucoma medications achieve on one side directly baroprotection by decreasing intraocular pressure and on the other side they produce indirectly vasoprotection, that is secondary to intraocular pressure lowering. The Cosopt, due to its Dorzolamide component, makes an exception since it produces directly both baroprotection by aqueous humor flow suppression and vasoprotection by increasing the blood flow within the retina, choroid, optic nerve head and retrobulbar area. Given these considerations as well as the fact that the ocular hypotensive effect of both the Cosopt and the latanoprost are equally potent, a question seems reasonable according to accepted standard i.e. Cosopt or latanoprost as primary glaucoma therapy? PMID:15279411

C?lug?ru, M; C?lug?ru, D

2004-01-01

307

Topics in Quantum Gravity  

Science.gov (United States)

We study some aspects of conformal field theory, wormhole physics and two-dimensional random surfaces. In spite of being rather different, these topics serve as examples of the issues that are involved, both at high and low energy scales, in formulating a quantum theory of gravity. In conformal field theory we show that fusion and braiding properties can be used to determine the operator product coefficients of the non-diagonal Wess-Zumino-Witten models. In wormhole physics we show how Coleman's proposed probability distribution would result in wormholes determining the value of theta_{rm QCD}. We attempt such a calculation and find the most probable value of theta_ {rm QCD} to be pi . This hints at a potential conflict with nature. In random surfaces we explore the behaviour of conformal field theories coupled to gravity and calculate some partition functions and correlation functions. Our results throw some light on the transition that is believed to occur when the central charge of the matter theory gets larger than one.

Trivedi, Sandip P.

308

Increased circulating procoagulant activity and thrombin generation in patients with myeloproliferative neoplasms.  

Science.gov (United States)

Microparticles (MPs) are membrane fragments ranging in size from 0.1 to 1 microm, and are considered as biomarkers reflecting prothrombotic state in many clinical diseases. The clinical course of myeloproliferative neoplasms (MPN) being frequently complicated by thrombotic events, we determined the MPs activity, i.e. circulating procoagulant activity (CPA), in polycythemia vera (PV) and essential thrombocythemia (ET) patients. To evaluate the influence of MPs on the coagulation, a thrombin generation test was realized in the absence and presence of thrombomodulin (TM). Compared with controls, patients had a higher CPA (24.0+/-9.0 vs 10.6+/-4.4 nM, p<0.001), which was associated with a lower inhibition of the thrombin generation in the presence of TM (20.1+/-9.5% vs 28.4+/-11.8%, p<0.001), compatible with a low sensitivity to TM. This sensitivity was influenced by the JAK2V617F mutational status, homozygous patients presenting the lowest inhibition rate of the thrombin generation. Filtration through a 0.22 microm membrane increased the sensitivity to TM in plasma, suggesting an influence of MPs in the "TM-resistance" observed in patients. Moreover, MPN patients receiving antiplatelet and/or cytoreductive therapies, our study suggests that CPA might be influenced by cytoreductive therapy. In conclusion, our data evidence in MPN patients the occurrence of an acquired "TM-resistance" partly determined by circulating microparticles. This TM-resistance might contribute to the hypercoagulable state observed in MPN patients, but the predictive value of the "TM-resistance" for thrombosis had not been evaluated. PMID:20656333

Duchemin, Jérôme; Ugo, Valérie; Ianotto, Jean-Christophe; Lecucq, Lydie; Mercier, Bernard; Abgrall, Jean-François

2010-09-01

309

Effect of oral contraceptives on thrombin generation measured via calibrated automated thrombography.  

Science.gov (United States)

In a study population consisting of healthy men (n = 8), women not using oral contraceptives (OC) (n = 28) and women using different kinds of OC (n = 187) we used calibrated automated thrombography (CAT) in the absence and presence of added activated protein C (APC) to compare parameters that can be obtained from thrombin generation curves, i.e. lag time, time to peak, peak height and endogenous thrombin potential (ETP). Both with and without APC, plasmas of OC users exhibited the shortest lag time and time to peak, and the highest peak height and ETP. In the absence of APC none of these parameters differed between users of OC containing different progestogens. In contrast, in the presence of APC shorter lag times and time to peak, and higher peak height and ETP were observed in plasma of users of gestodene-, desogestrel-, drospirenone- and cyproterone acetate-containing OC than in plasma of users of levonorgestrel- containing OC. The ETP determined in the absence of APC (ETP(-APC)) had no predictive value for the APCsr (r = 0.11; slope 0.9 x 10(-3); 95% CI: -0.1 x 10(-3) to 2.0 x 10(-3)) whereas the ETP measured in the presence of APC (ETP+APC) showed an excellent correlation with the APCsr (r = 0.95; slope 6.6 x 10(-3); 95% CI: 6.3 x 10(-3) to 6.9 x 10(-3)) indicating that the APCsr is entirely determined by the ETP+APC. In conclusion, OC use increases thrombin generation, but differential effects of second and third generation OCs on the protein C system likely determine the differences in the risk of venous thrombosis between these kinds of OC. PMID:18064335

Tchaikovski, Svetlana N; van Vliet, Huib A A M; Thomassen, M C L G D; Bertina, Rogier M; Rosendaal, Frits R; Sandset, Per-Morten; Helmerhorst, Frans M; Tans, Guido; Rosing, Jan

2007-12-01

310

Structure of saxthrombin, a thrombin-like enzyme from Gloydius saxatilis.  

Science.gov (United States)

Snake-venom thrombin-like enzymes (SVTLEs) are serine proteases that are widely distributed in snakes from the Crotalinae subfamily of the Viperidae. In contrast to other snake-venom serine proteases, they have a biochemical activity similar to that of thrombin and play an important role in the process of blood coagulation. However, SVTLEs cannot activate factor VIII, which is essential in blood-clot stabilization. Consequently, blood clots produced by SVTLEs are not stable and are cleared rapidly. This characteristic makes SVTLEs attractive as potential candidates for antithrombotic therapy. Saxthrombin, an SVTLE from Gloydius saxatilis, was purified and crystallized to obtain a high-quality crystal, from which data were acquired to 1.43?Å resolution. Preliminary X-ray diffraction analysis showed that the crystal belonged to space group C2, with unit-cell parameters a = 94.2, b = 52.2, c = 50.1?Å, ? = 96.7°. The crystal structure was determined by molecular replacement and the final R factor was 18.69%; the R(free) was 20.01%. This is the first report of a crystal structure of an SVTLE. Saxthrombin belongs to the typical ?/?-hydrolase fold of serine proteases. Its structure was compared with those of thrombin and other snake-venom serine proteases. The observed differences in the amino-acid composition of the loops surrounding the active site appear to contribute to different surface-charge distributions and thus alter the shape of the active-site cleft, which may explain the differences in substrate affinity. PMID:21821882

Huang, Kai; Zhao, Wei; Gao, Yongxiang; Wei, Wenqing; Teng, Maikun; Niu, Liwen

2011-08-01

311

Improving the thrombin inhibitory activity of glycyrrhizin, a triterpenic saponin, through a molecular simplification of the carbohydrate moiety.  

Science.gov (United States)

Glycyrrhizin, a saponin, and its aglycone glycyrrhetinic acid are natural products found in the Liquorice (Glycyrrhiza glabra L.) root extract. This saponin is known for its in vitro and in vivo thrombin inhibitory activity. The design and synthesis of five glycyrrhizin derivatives were carried out to improve the natural product activity. Compound 3b, a phthalic ester derivative of glycyrrhizin, presented a more pronounced thrombin inhibition (IC50  = 114.4 ± 1.3 ?m) than the saponin (IC50  = 235.7 ± 1.4 ?m). Molecular docking simulations performed to investigate the molecular interaction between compound 3b and the enzyme indicate that this product is, as previously determined for glycyrrhizin, an allosteric thrombin inhibitor. PMID:23964664

de Paula, Fernando T; Frauches, Petrina Q; Pedebos, Conrado; Berger, Markus; Gnoatto, Simone C B; Gossmann, Grace; Verli, Hugo; Guimarães, Jorge A; Graebin, Cedric S

2013-12-01

312

[Specific inhibition of thrombin activity during cardiopulmonary bypass reduces ischemia-reperfusion injury of the lung].  

Science.gov (United States)

The pathophysiologic role of thrombin in the development of lung injury after the normothermic cardiopulumonary bypass (CPB) was studied in the rabbit model. A control group (group D) was subjected to the pericardiotomy without institution of CPB. Group A rabbits (n = 6) underwent left heart bypass (80 ml/kg/min) for 60 minutes without occlusion of the systemic or pulmonary artery and a succeeding reduced flow (20-30 ml/kg/min) for another 30 minutes, group B rabbits (n = 6) underwent complete CPB (80 ml/kg/min) for 60 minutes in the working mode with occlusion of the pulmonary arterial trunk and a succeeding reduced flow without occlusion of the pulmonary artery for another 30 minutes, group C rabbits (n = 6) underwent the same CPB technique as group B in conjunction with continuous intravenous infusion of argatroban (60 micrograms/kg/min), the specific thrombin inhibitor. In this group, infusion of argatroban was initiated 60 minutes prior to institution of CPB and terminated at the end of the experiment. We sacrificed rabbits four hours after the experiment began, and assessed not only morphometrically thrombus formation, leukocytic infiltration and luminal narrowing of small-sized pulmonary arteries but also immunohistochemically the expression of tissue factor (TF) and IL-1 beta, and physico-functionally respiratory index (RI) and pulmonary vascular resistance (PVR). Rabbits in group A showed multiple occurrence of lung thrombi, luminal narrowing of small arteries, and mild infiltration of macrophages and neutrophils positive for TF, and, in addition, their RI and PVR became mildly worse. In group B, all these morphological and physico-functional parameters became much worse than those observed in group A rabbits (p < .01). In contrast, argatroban treatment could significantly improve these parameters (p < .01). The expression of TF and IL-1 beta, however, was not significantly different in group A, B and C. These findings indicate that thrombin function intimately participates in the development of pulmonary ischemia-reperfusion injury during CPB. In addition, the anti-thrombin treatment would be an effective therapeutical tool for the prevention of not only activation of extrinsic coagulation pathway but also its sequential inflammatory and circulatory disturbance in ischemia-reperfusion injury of lung during CPB. PMID:11246985

Tanaka, K

2001-01-01

313

Post-traumatic hepatic artery pseudoaneurysm treated with endovascular embolization and thrombin injection  

Science.gov (United States)

Post-traumatic hepatic artery pseudoaneurysm is uncommon, appearing in approximately 1% of hepatic trauma cases. Most are extrahepatic (80%) and have a late onset. Although they are usually asymptomatic, they should always be treated becasue of the high risk of complications, especially breakage. Currently the treatment of choice is endovascular embolization with coils or the exclusion of the pseudoaneurysm using other intravascular devices. Recently there have been accounts of a treatment that combines embolization with coils and image-guided percutaneous human thrombin injection. We present a case of post-traumatic hepatic artery pseudoaneurysm that was successfully treated using this combined technique.

Francisco, Lloret Estan; Asuncion, Lopez Conesa; Antonio, Capel Aleman; Ricardo, Robles Campos; Manuel, Reus Pintado; Caridad, Marin Hernandez

2010-01-01

314

Heparin-like tubings. II. Mechanism of the thrombin-antithrombin III reaction at the surface.  

Science.gov (United States)

In a previous paper we described the surface treatment of tubings made of polystyrene grafted by irradiation onto polyethylene tubular materials. As a result, polystyrene moieties of their inner face were substituted by sulphonate and aspartic acid sulphamide groups. In order to study the mechanism of the thrombin-antithrombin III reaction occurring at the modified surface and to determine the kinetics of the reaction, step by step experiments were set up involving either the protease adsorbed at the surface reacting with the antiprotease circulating in the solution or the opposite. These procedures allowed us to demonstrate the heparin-like catalytic activity of the tubings. PMID:3408793

Migonney, V; Fougnot, C; Jozefowicz, M

1988-05-01

315

Post-traumatic hepatic artery pseudoaneurysm treated with endovascular embolization and thrombin injection  

Directory of Open Access Journals (Sweden)

Full Text Available Post-traumatic hepatic artery pseudoaneurysm is uncommon, appearing in approximately 1% of hepatic trauma cases. Most are extrahepatic (80% and have a late onset. Although they are usually asymptomatic, they should always be treated becasue of the high risk of complications, especially breakage. Currently the treatment of choice is endovascular embolization with coils or the exclusion of the pseudoaneurysm using other intravascular devices. Recently there have been accounts of a treatment that combines embolization with coils and image-guided percutaneous human thrombin injection. We present a case of post-traumatic hepatic artery pseudoaneurysm that was successfully treated using this combined technique

Lloret Estañ Francisco, López Conesa Asunción, Capel Alemán Antonio, Robles Campos Ricardo, Reus Pintado Manuel, Marín Hernández Caridad

2010-02-01

316

Cystic artery pseudoaneurysm presenting as a complication of laparoscopic cholecystectomy treated with percutaneous thrombin injection.  

Science.gov (United States)

A 45-year-old woman status post laparoscopic cholecystectomy 3years ago presented with upper gastrointestinal bleeding. Endoscopy revealed hemobilia. Computed tomographic abdomen demonstrated a 2-cm aneurysm in the gall bladder fossa, consistent with a pseudoaneurysm. Initially, transcatheter coil embolization was attempted but recanalization of the aneurysm with recurrent bleeding in 2 days ensued. The aneurysm was then accessed percutaneously under ultrasound guidance and thrombin was injected into the aneurysm with subsequent complete thrombosis of the aneurysm and cessation of bleeding. PMID:24661399

Kumar, Abhishek; Sheikh, Ahmed; Partyka, Luke; Contractor, Sohail

2014-01-01

317

On the modeling of snake venom serine proteinase interactions with benzamidine-based thrombin inhibitors  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Pit viper venoms contain a number of serine proteinases that exhibit one or more thrombin-like activities on fibrinogen and platelets, this being the case for the kinin-releasing and fibrinogen-clotting KN-BJ from the venom of Bothrops jararaca. A three-dimensional structural model of the KN-BJ2 serine proteinase was built by homology modeling using the snake venom plasminogen activator TSV-PA as a major template and porcine kallikrein as additional structural support. A set of intrinsic buri...

Henriques, Elsa S.; Fonseca, Nelson; Ramos, Maria Joa?o

2004-01-01

318

Mechanism of the Anticoagulant Activity of Thrombin Mutant W215A/E217A*  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The thrombin mutant W215A/E217A (WE) is a potent anticoagulant both in vitro and in vivo. Previous x-ray structural studies have shown that WE assumes a partially collapsed conformation that is similar to the inactive E* form, which explains its drastically reduced activity toward substrate. Whether this collapsed conformation is genuine, rather than the result of crystal packing or the mutation introduced in the critical 215–217 ?-strand, and whether binding of thrombomodulin to exosite I...

Gandhi, Prafull S.; Page, Michael J.; Chen, Zhiwei; Bush-pelc, Leslie; Di Cera, Enrico

2009-01-01

319

An Automatic Topic Identification Algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement: Topic is a stream of words which stands for the content of a text. Knowing the topic of a document can help people to be aware from its content and facilitate their searching process. Approach: This paper proposes an automatic algorithm to identify the topic for a textual document based on the chunks corresponding to each sentences in the document. Results and conclusion: We achieved 86% matching for both total and partial matching in our experimental data sample.

Hossein S. Baghdadi

2011-01-01

320

Topics in quantum field theory  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this PhD-thesis some topics in quantum field theory are considered. The first chapter gives a background to these topics. The second chapter discusses renormalization. In particular it is shown how loop calculations can be performed when using the axial gauge fixing. Fermion creation and annihilation configurations for the one loop level are obtained and an example calculations was done to check that these lead to gauge invariant amplitudes. The next topic in the second chapter is renormal...

Dams, Christianus Johannes Franciscus

2006-01-01

 
 
 
 
321

CuInS2 quantum dots as a near-infrared fluorescent probe for detecting thrombin in human serum.  

Science.gov (United States)

This paper describes a novel, simple method for the highly sensitive and selective detection of thrombin using fibrinogen (Fib) and CuInS(2) quantum dots (QDs) as biosensing probes. Water-soluble near-infrared CuInS(2) QDs capped by mercaptopropionic acid (MPA) were directly synthesized by a hydrothermal method. Addition of fibrinogen to the CuInS(2) QDs solution led to the formation of a Fib-CuInS(2) QDs complex through electrostatic interactions and hydrogen bonding, and resulting in the enhancement of photoluminescence (PL) intensity and a red shift of the PL peak. Once thrombin was introduced into the Fib-CuInS(2) QDs system, it catalyzed the polymerization of the free and conjugated fibrinogen species to form insoluble fibrillar fibrin-CuInS(2) QDs agglutinates. After centrifugation, the PL intensity of the supernatants decreased upon increasing the concentration of thrombin. This Fib-CuInS(2) QDs probe provided a highly specific selectivity and a linear detection of thrombin in the range of 6.7 × 10(-11) to 3.9 × 10(-7) mol L(-1) with a detection limit (LOD) of about 8.7 × 10(-12) mol L(-1), and realized the thrombin detection in human serum samples directly. Compared with those obtained by using other nanomaterials and aptamer-based detection methods, this approach provided a lower LOD for thrombin detection. The proposed approach provides a simple and fast-responding procedure, which might hold a promising potential for application in the diagnosis of diseases associated with coagulation abnormalities and cancers. PMID:23061093

Gao, Xue; Liu, Xingcen; Lin, Zihan; Liu, Siyu; Su, Xingguang

2012-12-01

322

Thrombin-induced endothelial barrier disruption in intact microvessels: role of RhoA/Rho kinase-myosin phosphatase axis.  

Science.gov (United States)

Endothelial hyperpermeability is regulated by a myosin light chain-2 (MLC2) phosphorylation-dependent contractile mechanism. Thrombin is a potent inducer of hyperpermeability of cultured monolayers of endothelial cells (ECs) via Rho kinase-mediated MLC2-phosphorylation. The aim of the present study was to investigate the effects of thrombin on in situ endothelial morphology and barrier integrity. Cytoskeletal dynamics, regions of paracellular flux, and MLC2-phosphorylation of ECs were visualized by digital three-dimensional imaging microscopy of pressurized rat kidney arterioles. Myosin phosphatase targeting subunit (MYPT1)-phosphorylation was used as a surrogate marker for Rho kinase activity. Thrombin induced the formation of F-actin filaments in ECs in situ and rounding of the ECs in the absence of obvious formation of gaps between ECs. These changes were accompanied by an increase in MLC2 phosphorylation and a decrease in barrier integrity. In vitro analysis revealed that Rho kinase activity on F-actin filaments was associated with a contractile response that enhanced opening of the barrier. Rho kinase activity was not detectable on F-actin filaments induced by histamine, an inducer of a more transient hyperpermeability response. Inhibition of the myosin phosphatase mimicked the effects of thrombin on barrier function. The thrombin-induced changes in in situ MLC2 phosphorylation and barrier function were Rho kinase dependent. These data demonstrate a direct effect of thrombin on EC morphology and barrier integrity in intact microvessels. Furthermore, they establish an important contribution of enhanced Rho kinase activity to the development of prolonged but not transient types of endothelial barrier dysfunction. PMID:18353893

van Nieuw Amerongen, G P; Musters, R J P; Eringa, E C; Sipkema, P; van Hinsbergh, V W M

2008-05-01

323

Expression of Active Recombinant Human Tissue-Type Plasminogen Activator by Using In Vivo Polyhydroxybutyrate Granule Display?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recombinant human tissue plasminogen activator (rPA) is a truncated version of tissue plasminogen activator (tPA), which contains nine disulfide bonds and is prone to forming inactive inclusion bodies when expressed in bacteria. To obtain functional rPA expression, we displayed the rPA on the surface of polyhydroxybutyrate (PHB) granules using phasin as the affinity tag. rPA was fused to the N terminus of the phasin protein with a thrombin cleavage site as the linker. Sodium dodecyl sulfate-p...

Geng, Yanping; Wang, Shengjun; Qi, Qingsheng

2010-01-01

324

Recombinant methods and materials  

Energy Technology Data Exchange (ETDEWEB)

This patent describes a method for stably effecting the insertion or deletion of a selected DNA sequence at a specific site in a viral genome. The method consists of: (1) isolating from the genome a linear DNA fragment comprising both (a) the specific site determined for insertion or deletion of selected DNA sequence and (b) flanking DNA sequences normally preceding and following the site; (2) preparing first and second altered genome fragments from the fragment isolated in step (1). (a) the first altered fragment comprising the fragment comprising a thymidine kinase gene in a position intermediate the ends of the fragment, and (b) the second altered fragment comprising the fragment having the selected DNA sequence inserted therein or deleted therefrom; (3) contacting the genome with the first altered fragment under conditions permitting recombination at sites of DNA sequence homology, selecting for a recombinant genome comprising the thymidine kinase gene, and isolating the recombinant genome; and (4) contacting the recombinant genome isolated in step (3) with the second altered fragment under conditions permitting recombination at sites of DNA sequence homology, selecting for a recombinant genome lacking the thymidine kinase gene, and isolating the recombinant genome product.

Roizman, B.; Post, L.E.

1988-09-06

325

Dielectronic recombination: an introduction  

International Nuclear Information System (INIS)

Atoms contained in hot plasmas such as those found in stellar coronae and controlled fusion devices are subject to intense bombardment by electrons whose energy distribution is characterized by the plasma temperature. Collisions can cause multiple ionization of the atom and the electrons may also recombine with the ion. The distribution of ion charge states in a plasma at a given temperature depends upon the competing rates of ionization and recombination. When an unbound electron recombines the gain in potential energy must be removed in some way. Two processes are known to be important in recombination: radiative recombination (RR) in which a photon is released whose energy is exactly equal to the potential energy gain, and dielectronic recombination (DR) in which a continuum electron excites a previously bound electron and in so doing loses just enough energy to be captured into a bound state (nl). The latter process results in a doubly excited ion in a lower charge state which may either auto-ionize or emit a photon resulting in a stabilized recombination. (Auth.)

1983-08-02

326

The Use of Direct Thrombin Injection to Treat a Type II Endoleak Following Endovascular Repair of Abdominal Aortic Aneurysm  

International Nuclear Information System (INIS)

This report describes the use of thrombin to treat a type II endoleak which was causing continued abdominal aortic aneurysm expansion in a patient who had undergone endovascular repair. A small quantity of thrombin was injected into the leak by a percutaneous approach directly into the aneurysm sac using color doppler ultrasound. The procedure was successful and required only a few minutes to perform. We believe this procedure is an alternative to some of the more complex and technically challenging means of treating this lesion

2003-09-01

327

C-Src/Jak2/PDGFR/PKC?-dependent MMP-9 induction is required for thrombin-stimulated rat brain astrocytes migration.  

Science.gov (United States)

Among matrix metalloproteinases (MMPs), MMP-9 has been observed in patients with brain inflammatory diseases and may contribute to the pathology of brain diseases. Thrombin has been known as a regulator of MMP-9 expression and cells migration. However, the mechanisms underlying thrombin-induced MMP-9 expression in rat brain astrocytes (RBA-1 cells) were not completely understood. Here, we demonstrated that thrombin induced the expression of pro-form MMP-9 in RBA-1 cells and cells migration which were attenuated by pretreatment with the inhibitor of receptor tyrosine kinase (Genistein), c-Src (PP1), Jak2 (AG490), PDGFR (AG1296), PI3K (LY294002), Akt (SH-5), PKCs (Ro318220), PKC? (Rottlerin), or NF-?B (Bay11-7082) and transfection with siRNA of c-Src, PDGFR, Akt, PKC?, ATF2, p65, IKK?, or IKK?. In addition, thrombin-stimulated c-Src, Jak2, or PDGFR phosphorylation was inhibited by a thrombin inhibitor (PPACK), PP1, AG490, or AG1296. Thrombin further stimulated c-Src and PDGFR complex formation in RBA-1 cells. Thrombin also stimulated Akt and PKC? phosphorylation and PKC? translocation which were reduced by PPACK, PP1, AG490, AG1296, or LY294002. We further observed that thrombin markedly stimulated ATF2 or I?B? phosphorylation and NF-?B p65 translocation which were inhibited by Rottlerin or LY294002. Finally, thrombin stimulated in vivo binding of p65 to the MMP-9 promoter, which was reduced by pretreatment with Rottlerin or LY294002. These results concluded that in RBA-1 cells, thrombin activated a c-Src/Jak2/PDGFR/PI3K/Akt/PKC? pathway, which in turn triggered ATF2 and NF-?B activation and ultimately induced MMP-9 expression associated with cell migration. PMID:24018979

Lin, Chih-Chung; Lee, I-Ta; Chi, Pei-Ling; Hsieh, Hsi-Lung; Cheng, Shin-Ei; Hsiao, Li-Der; Liu, Chiung-Ju; Yang, Chuen-Mao

2014-04-01

328

Hot topic [editorial  

International Nuclear Information System (INIS)

There is strong evidence for the human impact on climate change, but we should not ignore those who think otherwise. Unseasonably warm weather in many parts of Europe and North America last month will probably have added to the impression in many people's minds that climate change is a reality and that humans are guilty of warming our planet. The several hundred members of the United Nations' Intergovernmental Panel on Climate Change (IPCC) certainly think that the evidence for anthropogenic climate change is solid. Although Physics World was unable to obtain a copy of the IPCC's latest report on the science of climate change before its release date of 2 February - a clear sign of how sensitive its findings are - hints from those involved in writing the report suggest that the IPCC will have strengthened its conclusions, previously stated in 2001, that humans are heating up the Earth. While most scientists probably share this view, there are some who think otherwise. Many of those are either scientifically ill-informed or have dubious links with the energy industry. But some have genuine doubts. One bona fide sceptic is Richard Lindzen, a climate physicist from the Massachusetts Institute of Technology in the US, who was involved in preparing the IPCC's 2001 scientific report. While he does not dispute that the Earth is getting hotter, Lindzen thinks that, in all probability, the warming is largely the result of natural variations in the Earth's climate. Lindzen believes that climate models, although rooted in physics, contain far too many uncertainties to provide accurate forecasts. Indeed, mainstream climate physicists admit their computer models are far from perfect. Writing in their feature, for example, the chief scientist of the UK's Meteorological Office and colleagues describe how hard it is to incorporate the impact of clouds, which are much smaller than the resolution of the best models. They also warn that if clouds were modelled incorrectly, climate simulations 'would be seriously in error'. One may ask if this magazine should give space to Lindzen or those involved in geoengineering to air their views. Given the uncertainties still present within climate models and the potential costs of dealing with global warming, it would be wrong for Physics World to ignore those outside the mainstream. After all, as Richard Feynman once wrote: 'There is no harm in doubt and scepticism, for it is through these that new discoveries are made'. Physicists should never take anything at face value, not least a topic as important as climate change. (U.K.)

2007-02-01

329

The G protein ?? subunit mediates reannealing of adherens junctions to reverse endothelial permeability increase by thrombin  

Science.gov (United States)

The inflammatory mediator thrombin proteolytically activates protease-activated receptor (PAR1) eliciting a transient, but reversible increase in vascular permeability. PAR1-induced dissociation of G? subunit from heterotrimeric Gq and G12/G13 proteins is known to signal the increase in endothelial permeability. However, the role of released G?? is unknown. We now show that impairment of G?? function does not affect the permeability increase induced by PAR1, but prevents reannealing of adherens junctions (AJ), thereby persistently elevating endothelial permeability. We observed that in the naive endothelium G?1, the predominant G? isoform is sequestered by receptor for activated C kinase 1 (RACK1). Thrombin induced dissociation of G?1 from RACK1, resulting in G?1 interaction with Fyn and focal adhesion kinase (FAK) required for FAK activation. RACK1 depletion triggered G?1 activation of FAK and endothelial barrier recovery, whereas Fyn knockdown interrupted with G?1-induced barrier recovery indicating RACK1 negatively regulates G?1-Fyn signaling. Activated FAK associated with AJ and stimulated AJ reassembly in a Fyn-dependent manner. Fyn deletion prevented FAK activation and augmented lung vascular permeability increase induced by PAR1 agonist. Rescuing FAK activation in fyn?/? mice attenuated the rise in lung vascular permeability. Our results demonstrate that G?1-mediated Fyn activation integrates FAK with AJ, preventing persistent endothelial barrier leakiness.

Knezevic, Nebojsa; Tauseef, Mohammad; Thennes, Tracy

2009-01-01

330

Ionic interactions in the formation of the thrombin-hirudin complex.  

Science.gov (United States)

Site-directed mutagenesis has been used to examine the importance of each of the acidic C-terminal residues of hirudin in the formation of its complex with alpha-thrombin. The contribution to binding energy of acidic residues in the 11 C-terminal amino acids varied from 2.3 to 5.9 kJ.mol-1. The differences between the contributions of individual residues were smaller than would be expected from the crystal structures of the thrombin-hirudin complex. In particular, the small effect (2.4 kJ.mol-1) for the replacement of Asp-55 was surprising in view of the two salt bridges made by this residue. The results of studies involving multiple mutations indicated that the additivity of the effects varied with the position of the mutation. Whereas the effect of mutations involving the glutamic acid residues at positions 61 and 62 were additive, non-additivity was observed with the glutamic acid residues at positions 57 and 58. PMID:1674862

Betz, A; Hofsteenge, J; Stone, S R

1991-05-01

331

Influenza virus H1N1 activates platelets through Fc?RIIA signaling and thrombin generation.  

Science.gov (United States)

Platelets play crucial functions in hemostasis and the prevention of bleeding. During H1N1 influenza A virus infection, platelets display activation markers. The platelet activation triggers during H1N1 infection remain elusive. We observed that H1N1 induces surface receptor activation, lipid mediator synthesis, and release of microparticles from platelets. These activation processes require the presence of serum/plasma, pointing to the contribution of soluble factor(s). Considering that immune complexes in the H1N1 pandemic were reported to play a pathogenic role, we assessed their contribution in H1N1-induced platelet activation. In influenza-immunized subjects, we observed that the virus scaffolds with immunoglobulin G (IgG) to form immune complexes that promote platelet activation. Mechanistically, this activation occurs through stimulation of low-affinity type 2 receptor for Fc portion of IgG (Fc?RIIA), a receptor for immune complexes, independently of thrombin. Using a combination of in vitro and in vivo approaches, we found that the antibodies from H3N2-immunized mice activate transgenic mouse platelets that express Fc?RIIA when put in the presence of H1N1, suggesting that cross-reacting influenza antibodies suffice. Alternatively, H1N1 can activate platelets via thrombin formation, independently of complement and Fc?RIIA. These observations identify both the adaptive immune response and the innate response against pathogens as 2 intertwined processes that activate platelets during influenza infections. PMID:24665136

Boilard, Eric; Paré, Guillaume; Rousseau, Matthieu; Cloutier, Nathalie; Dubuc, Isabelle; Lévesque, Tania; Borgeat, Pierre; Flamand, Louis

2014-05-01

332

Recombination in Circulating Enteroviruses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Recombination is a well-known phenomenon for enteroviruses. However, the actual extent of recombination in circulating nonpoliovirus enteroviruses is not known. We have analyzed the phylogenetic relationships in four genome regions, VP1, 2A, 3D, and the 5? nontranslated region (NTR), of 40 enterovirus B strains (coxsackie B viruses and echoviruses) representing 11 serotypes and isolated in 1981 to 2002 in the former Soviet Union states. In the VP1 region, strains of the same serotype expect...

2003-01-01

333

Mental mechanisms for topics identification.  

Science.gov (United States)

Topics identification (TI) is the process that consists in determining the main themes present in natural language documents. The current TI modeling paradigm aims at acquiring semantic information from statistic properties of large text datasets. We investigate the mental mechanisms responsible for the identification of topics in a single document given existing knowledge. Our main hypothesis is that topics are the result of accumulated neural activation of loosely organized information stored in long-term memory (LTM). We experimentally tested our hypothesis with a computational model that simulates LTM activation. The model assumes activation decay as an unavoidable phenomenon originating from the bioelectric nature of neural systems. Since decay should negatively affect the quality of topics, the model predicts the presence of short-term memory (STM) to keep the focus of attention on a few words, with the expected outcome of restoring quality to a baseline level. Our experiments measured topics quality of over 300 documents with various decay rates and STM capacity. Our results showed that accumulated activation of loosely organized information was an effective mental computational commodity to identify topics. It was furthermore confirmed that rapid decay is detrimental to topics quality but that limited capacity STM restores quality to a baseline level, even exceeding it slightly. PMID:24744775

Massey, Louis

2014-01-01

334

Superior Mesenteric Artery Pseudoaneurysm Following Pancreaticoduodenectomy: Management by Endovascular Stent-Graft Placement and Transluminal Thrombin Injection  

International Nuclear Information System (INIS)

Superior mesenteric artery (SMA) pseudoaneurysm formation is a rare and potentially fatal postoperative complication. Herein we present a case of a large post-pancreaticoduodenectomy SMA pseudoaneurysm that required thrombin injection after initial stent-graft deployment to accomplish complete pseudoaneurysm occlusion

2007-06-01

335

Endogenous thrombin potential as a novel method for the characterization of procoagulant snake venoms and the efficacy of antivenom.  

Science.gov (United States)

Venom-induced consumption coagulopathy occurs in snake envenoming worldwide but the interaction between procoagulant snake venoms and human coagulation remains poorly understood. We aimed to evaluate an assay using endogenous thrombin potential (ETP) to investigate the procoagulant properties of a range of Australian whole venoms in human plasma and compared this to traditional clotting and prothrombinase activity studies. We developed a novel modification of ETP using procoagulant snake venoms to trigger thrombin production. This was used to characterise the relative potency, calcium and clotting factor requirements of five important Australian snake venoms and efficacy of commercial antivenom, and compared this to prothrombinase activity and clotting assays. All five venoms initiated thrombin generation in the absence and presence of calcium. Pseudonaja textilis (Brown snake; pTaipan) venom to intermediate with N. scutatus and H. stephensii venoms to most potent with P. textilis and Tropidechis carinatus (Rough-scale snake) venoms. ETPs for N. scutatus, T. carinatus and H. stephensii venoms were severely reduced with factor V deficient plasma. Antivenom neutralized the thrombin generating capacity but not prothrombin substrate cleaving ability of the venoms. Contrary to previous studies using clotting tests and factor Xa substrates, these venoms differ in calcium requirement. ETP is a useful assay to investigate mechanisms of other procoagulant venoms and is a robust method of assessing antivenom efficacy. PMID:20338189

Isbister, Geoffrey K; Woods, David; Alley, Steven; O'Leary, Margaret A; Seldon, Michael; Lincz, Lisa F

2010-08-01

336

High-throughput synthesis and optimization of thrombin inhibitors via urazole alpha-addition and Michael addition.  

Science.gov (United States)

A novel alpha-addition of propiolates to urazoles followed by Michael addition of a variety of nucleophiles has been developed for rapid production and optimization of peptidomimetic drug leads. This technology has produced a number of highly potent and selective inhibitors of the serine protease, thrombin. PMID:12668009

Boatman, P Douglas; Urban, Jan; Nguyen, Minh; Qabar, Maher; Kahn, Michael

2003-04-17

337

GDP beta S enhances the activation of phospholipase C caused by thrombin in human platelets: evidence for involvement of an inhibitory GTP-binding protein  

International Nuclear Information System (INIS)

Guanosine 5'-O-thiotriphosphate (GTP gamma S) and thrombin stimulate the activity of phospholipase C in platelets that have been permeabilized with saponin and whose inositol phospholipids have been prelabeled with [3H]inositol. Ca2+ has opposite effects on the formation of [3H]inositol phosphates induced by thrombin or GTP gamma S. While the action of GTP gamma S on the formation of [3H]inositol phosphates is inhibited by Ca2+, action of thrombin is stimulated by Ca2+. Guanosine 5'-O-(2-thiodiphosphate) (GDP beta S), which inhibits the function of GTP-binding proteins, also inhibits the effect of GTP gamma S on phospholipase C stimulation but, surprisingly, increases the effect of thrombin. Ca2+ increases the inhibitory effect of GDP beta S on GTP gamma S activation of phospholipase C, but Ca2+ further enhances the stimulatory effect of GDP beta S on the thrombin activation of phospholipase C. This indicates that two mechanisms are responsible for the activation of phospholipase C in platelets. A GTP-binding protein is responsible for regulation of phospholipase C induced by GTP gamma S, while the effect of thrombin on the stimulation of phospholipase C is independent of GTP-binding proteins. However, the effect of thrombin may be modulated by the action of an inhibitory GTP-binding protein

1987-05-14

338

GDP beta S enhances the activation of phospholipase C caused by thrombin in human platelets: evidence for involvement of an inhibitory GTP-binding protein  

Energy Technology Data Exchange (ETDEWEB)

Guanosine 5'-O-thiotriphosphate (GTP gamma S) and thrombin stimulate the activity of phospholipase C in platelets that have been permeabilized with saponin and whose inositol phospholipids have been prelabeled with (/sup 3/H)inositol. Ca/sup 2 +/ has opposite effects on the formation of (/sup 3/H)inositol phosphates induced by thrombin or GTP gamma S. While the action of GTP gamma S on the formation of (/sup 3/H)inositol phosphates is inhibited by Ca/sup 2 +/, action of thrombin is stimulated by Ca/sup 2 +/. Guanosine 5'-O-(2-thiodiphosphate) (GDP beta S), which inhibits the function of GTP-binding proteins, also inhibits the effect of GTP gamma S on phospholipase C stimulation but, surprisingly, increases the effect of thrombin. Ca/sup 2 +/ increases the inhibitory effect of GDP beta S on GTP gamma S activation of phospholipase C, but Ca/sup 2 +/ further enhances the stimulatory effect of GDP beta S on the thrombin activation of phospholipase C. This indicates that two mechanisms are responsible for the activation of phospholipase C in platelets. A GTP-binding protein is responsible for regulation of phospholipase C induced by GTP gamma S, while the effect of thrombin on the stimulation of phospholipase C is independent of GTP-binding proteins. However, the effect of thrombin may be modulated by the action of an inhibitory GTP-binding protein.

Oberdisse, E.; Lapetina, E.G.

1987-05-14

339

A electrochemiluminescence aptasensor for detection of thrombin incorporating the capture aptamer labeled with gold nanoparticles immobilized onto the thio-silanized ITO electrode  

International Nuclear Information System (INIS)

A novel electrochemiluminescence (ECL) aptasensor was proposed for sensitive and cost-effective detection of the target thrombin adopted an aptamer-based sandwich format. To detect thrombin, capture aptamers labeled with gold nanoparticles (AuNPs) were first immobilized onto the thio-silanized ITO electrode surface through strong Au-S bonds. After catching the target thrombin, signal aptamers tagged with ECL labels were attached to the assembled electrode surface. As a result, an AuNPs-capture-aptamer/thrombin/ECL-tagged-signal-aptamer sandwich type was formed. Treating the resulting electrode surface with tri-n-propylamine (TPA) and applying a swept potential to the electrode, ECL response was generated which realized the detection of target protein. Spectroscopy and electrochemical impedance techniques were used to characterize and confirm the fabrication of the ECL aptasensor. AuNPs amplification and smart sensor fabrication art were implemented for the sensitive and cost-effective detection purpose. Signal-to-dose curve excellently followed a sandwich format equation and could be used to quantify the protein, and the detection limit was estimated to be 10 nM. Other forms of thrombin such as ?- and ?-thrombins had negligible response, which indicated a high specificity of ?-thrombin detection. The aptasensor opened up new fields of aptamer applications in ECL domain, a highly sensitive technique, and had a promising perspective to be applied in microarray analysis

2008-10-17

340

Personal experiences in direct ultrasound-guided injection of thrombin into the lumen of pseudoaneurysm as a method of treatment in case of iatrogenic femoral artery damage  

International Nuclear Information System (INIS)

Background: Pseudoaneurysms constitute a quite common complication of procedures requiring puncture of the common femoral artery. The risk factors of the condition include: obesity, arterial hypertension, sex (more prevalent in males) as well as antithrombotic therapy. Material/Methods: The US-guided injection of thrombin into the pseudoaneurysm lumen was performed in patients referred from the Department of Invasive Cardiology who had undergone coronarography or coronary angioplasty. Pseudoaneurysms constituted the complication of common femoral artery canulation. After setting the diagnosis of pseudoaneurysm by means of Doppler ultrasound, patients with large pseudoaneurysms of volume exceeding 10 mm were qualified for thrombin injection. Generally, 33 patients underwent the treatment. In 3 cases - due to the presence of multiocular pseudoaneurysm - thrombin was administered twice. Results: Taking into account the safety of the procedure, ultimately 33 patients were qualified for thrombin administration, in whom aneurism of diameter exceeding 10 mm was diagnosed. In 3 patients with aneurysm of less than 10 mm, only a compression band was used prophylactically. In one case, because of a considerable oedema surrounding the tissue, as well as deep location of the aneurysm in the groin, thrombin treatment was not given due to technical reasons. In 30 cases, single administration of thrombin was effective and resulted in a complete thrombosis of the pseudoaneurism lumen within a couple of seconds following thrombin injection. In 3 patients with multicellular aneurysm, thrombin was given twice, resulting in a total obliteration of the pseudoaneurysm in two cases only. No complications were observed after the performed procedures. No recanalisation of pseudoaneurysms was demonstrated in follow-up examinations. Conclusions: 1. Direct thrombin injection into the pseudoaneurysm lumen can constitute an alternative method of treatment for open surgical techniques. 2. The procedure is highly effective, cheap and minimally invasive. (authors)

2010-01-01

 
 
 
 
341

Thrombin generation in first-degree relatives of patients with venous thromboembolism who have factor V Leiden. A pilot study.  

Science.gov (United States)

The thrombin generation test appears to be a highly sensitive and specific test in the detection of thrombophilia in patients with venous thromboembolism. We aimed to determine the accuracy of the thrombin generation test to detect factor V Leiden and/or other prothrombotic states in first-degree relatives of patients with venous thromboembolism and factor V Leiden. Sixty-two first-degree relatives of 21 index cases were tested for factor V Leiden, the G20210A prothrombin gene mutation and thrombin generation. Information about oestrogen therapy and previous VTE was also collected. The normalized Thrombomodulin sensitivity ratio (n-TMsr) was defined as the ratio of endogenous thrombin potential determined in the presence and absence of thrombomodulin which was normalized against the same ratio determined in normal control plasma. The mean n-TMsr was 1.37 (+/- 0.33) in the 45 relatives with one or more prothrombotic state (factor V Leiden, G20210A prothrombin mutation, oestrogen therapy or hormonal therapy) and 1.02 (+/- 0.34) in the 17 relatives without prothrombotic state (p = 0.001). The positive predictive value was 90.3 (95%CI, 73.1-97.4). In relatives with an abnormal n-TMsr, the adjusted odds ratio for having a prothrombotic state was 8.3 (95%CI, 1.9-36.9) and the adjusted odds ratio for having the factor V Leiden was 14.3 (95%CI, 2.9-71.2). An abnormal thrombin generation test appears highly predictive for having factor V Leiden and/or other prothrombotic states in first-degree relatives of patients with venous thromboembolism and factor V Leiden. PMID:18217158

Couturaud, Francis; Duchemin, Jérôme; Leroyer, Christophe; Delahousse, Bénédicte; Abgrall, Jean François; Mottier, Dominique

2008-01-01

342

Anticoagulant activity of a unique sulfated pyranosic (1->3)-?-L-arabinan through direct interaction with thrombin.  

Science.gov (United States)

A highly sulfated 3-linked ?-arabinan (Ab1) with arabinose in the pyranose form was obtained from green seaweed Codium vermilara (Bryopsidales). It comprised major amounts of units sulfated on C-2 and C-4 and constitutes the first polysaccharide of this type isolated in the pure form and fully characterized. Ab1 showed anticoagulant activity by global coagulation tests. Less sulfated arabinans obtained from the same seaweed have less or no activity. Ab1 exerts its activity through direct and indirect (antithrombin- and heparin cofactor II-mediated) inhibition of thrombin. Direct thrombin inhibition was studied in detail. By native PAGE, it was possible to detect formation of a complex between Ab1 and human thrombin (HT). Ab1 binding to HT was measured by fluorescence spectroscopy. CD spectra of the Ab1 complex suggested that ligand binding induced a small conformational change on HT. Ab1-thrombin interactions were studied by molecular dynamic simulations using the persulfated octasaccharide as model compound. Most carbohydrate-protein contacts would occur by interaction of sulfate groups with basic amino acid residues on the surface of the enzyme, more than 60% of them being performed by the exosite 2-composing residues. In these interactions, the sulfate groups on C-2 were shown to interact more intensely with the thrombin structure. In contrast, the disulfated oligosaccharide does not promote major conformational modifications at the catalytic site when complexed to exosite 1. These results show that this novel pyranosic sulfated arabinan Ab1 exerts its anticoagulant activity by a mechanism different from those found previously for other sulfated polysaccharides and glycosaminoglycans. PMID:23161548

Fernández, Paula V; Quintana, Irene; Cerezo, Alberto S; Caramelo, Julio J; Pol-Fachin, Laercio; Verli, Hugo; Estevez, José M; Ciancia, Marina

2013-01-01

343

Clindamycin and Benzoyl Peroxide Topical  

Science.gov (United States)

The combination of clindamycin and benzoyl peroxide is used to treat acne. Clindamycin and benzoyl peroxide are in a class of medications called topical antibiotics. The combination of clindamycin and benzoyl peroxide works by killing the bacteria ...

344

Iodine Absorption After Topical Administration  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Absorption from povidone-iodine preparations after topical administration has been reported to be negligible, but an elderly woman had increased serum iodine levels with possible metabolic complications after povidone-iodine solution was applied to decubitus ulcers.

Cruz, Francine Dela; Brown, Deborah Harper; Leikin, Jerrold B.; Franklin, Cory; Hryhorczuk, Daniel O.

1987-01-01

345

Selected topics in nuclear structure  

International Nuclear Information System (INIS)

The collection of abstracts on selected topics in nuclear structure are given. Special attention pays to collective excitations and high-spin states of nuclei, giant resonance structure, nuclear reaction mechanisms and so on

1994-07-05

346

Special topics in spectral distributions  

International Nuclear Information System (INIS)

We discuss two problems which relate to the foundations of the subject, and a third about asymptotic properties of spectral distributions. We give also a brief list of topics which should be further explored

1979-09-13

347

Present topics of nuclear energy  

International Nuclear Information System (INIS)

The report is discussing the topics: Reprocessing of spent fuel elements; Final storage of radioactive wastes; Effects of thermal power plants upon the climate; Safeguarding of nuclear facilities and fissionable materials; Properties and possibilities of plutonium. (orig./HP)

1981-01-01

348

Memory-Efficient Topic Modeling  

Digital Repository Infrastructure Vision for European Research (DRIVER)

As one of the simplest probabilistic topic modeling techniques, latent Dirichlet allocation (LDA) has found many important applications in text mining, computer vision and computational biology. Recent training algorithms for LDA can be interpreted within a unified message passing framework. However, message passing requires storing previous messages with a large amount of memory space, increasing linearly with the number of documents or the number of topics. Therefore, the ...

Zeng, Jia; Liu, Zhi-qiang; Cao, Xiao-qin

2012-01-01

349

Topics of Bioengineering in Wikipedia  

Directory of Open Access Journals (Sweden)

Full Text Available The present report aims to give a snapshot of how topics from the field of bioengineering (bioinformatics, bioprocess systems, biomedical engineering, biotechnology, etc. are currently covered in the free electronic encyclopedia Wikipedia. It also offers insights and information about what Wikipedia is, how it functions, how and when to cite Wikipedian articles, if necessary. Several external wikis, devoted to topics of bioengineering, are also listed and reviewed.

Vassia Atanassova

2009-10-01

350

Ultrasensitive electrochemiluminescence detection of thrombin based on aptamer and cystamine modified gold nanoparticle probe  

Science.gov (United States)

Recently, our group showed that one can detect specific oligonucleotides at low femtomolar levels with the electrochemiluminescence (ECL) biobarcode approach based on tris-(2, 2'-bipyridyl) ruthenium (TBR)-labeled cysteamine. It would be a significant advance to use the cysteamine assisted ECL biobarcode assay to detect protein targets in addition to DNA targets. Taking advantage of sandwich binding of two affinity aptamers for increased specificity, TBR-cysteamine as biobarcode for signal amplification and magnetic beads based ECL technology for rapid detection, a promising assay for thrombin quantification is developed. The sandwich complex could be selectively captured by micromagnetic particles and then quantified by ECL signals. Current cysteamine-Gold nanoparticle (GNP) conjugates based ECL biobarcode assay is expected to become a powerful tool for protein analysis.

Duan, Ruixue; Zhou, Xiaoming

2011-11-01

351

G-quadruplex formation of thrombin-binding aptamer detected by electrospray ionization mass spectrometry.  

Science.gov (United States)

Electrospray ionization mass spectrometry detected the formation of the G-quadruplex structure of the thrombin-binding aptamer, d(GGTTGGTGTGGTTGG), and established its specific interaction with metal ions. One piece of evidence that the bonding in the gas phase is via the G-quadruplex form is the enhanced binding, with respect to other metal ions, of the aptamer with Sr2+, Pb2+, Ba2+, and K+, which are of similar size. Another is the lack of specific binding with controls in which the G's are replaced with A's. The most convincing evidence is the extent of H/D exchange of the gas-phase aptamer as compared to that bound to K+ and Sr2+. The latter two complexes exchange six and nine fewer H's, indicating a significant increase in protection upon binding to the metals. Mass spectrometry will be an important tool in understanding G-quadruplexes, which are particularly important in DNA telomers. PMID:12515502

Vairamani, M; Gross, Michael L

2003-01-01

352

Recent Developments in Dissociative Recombination  

International Nuclear Information System (INIS)

There have been a number of recent developments in dissociative recombination research as it relates to ITER, that should be highlighted. These concern primarily experimental and modelling issues and this document will not touch upon the topics of the other scientists involved in DR studies that are present at the meeting. The topic of branching ratios in general is a topic fundamental to DR especially how it influences the formation of radical and stable neutral molecules that again might play a role in particle formation. It should be remembered that the reactions of neutral radicals to form cyclic compounds are responsible for the formation of soot in combustion, though the role played by ions in flames is at best uncertain. In the near wall plasma environment, ion processes may well be more important since neutral species are rarer. Modelling studies by Pernot and collaborators at the Universite de Paris-Sud have shown that if one compares the yields of individual neutral species in ion-chemistry models (in this particular case, the ionosphere of Titan), and if one assumes that DR reactions of hydrocarbon ions primarily decay via the ejection of a hydrogen ion (which is assumed by most Titan ionospheric models) and if one compares these predictions with those coming from a model where actual measured branching ratios are used, differences of up to 5 orders of magnitude are found. This shows very clearly the need for branching ratio studies. In early merged beam studies of DR performed in Canada in the 1970's, it was noticed that cross sections for polyatomic species typically displayed a sharp fall-off above 0.1 eV. This has since been seen in many storage ring studies and clearly this has important consequences for ITER chemistry where plasma temperatures are likely to be well above ambient. In a recent analysis, Jungen and Pratt have explained this phenomenon on the basis that the recombination is dominated by the indirect process (initial capture into a vibrationally excited, neutral Rydberg state) in which the propensity rule (+?v=1) dominates the capture. When the electron energy exceeds that between the v'=0 and v'=1 levels of the ion, where the capture must now involve a ?v=2 transition, this will be much less effective and so the cross section drops precipitously. This assumes of course that the recombining ion is primarily in the ground v=0 level. H3+ continues to be an active subject of research and a very recent experiment at the TSR ring in Heidelberg has examined the influence of rotational excitation on the rate of the recombination. This is a very beautiful study but an important outcome is that even though a cryogenically cooled storage trap was used to produce the ions, the internal rotational temperature of the ions was never found to be below 150K. This suggests that ion cooling by storage in the ring leads eventually to an equilibrium value for the internal energy of the ions as they are de-excited/re-excited by passage through the electron cooler. As observed in earlier merged beam experiments in Canada, the extraction field in the ion source plays an important role in determining the excitation state of the ions as collisions outside the source can lead to re-heating. Indeed in the TSR experiments using a conventional Penning source and a normal extraction field, the ions were found to have a rotational temperature of several thousands of degrees. This clearly has important significance for earlier measurements taken in storage rings. Finally, the world will soon have a new storage ring facility for dissociative recombination research and this will be in Langzhou in China. This machine will have a higher magnetic rigidity that previous rings used for DR and so heavier ions and higher mass resolution experiments can be performed there. Experimental operation of this new ring is expected to commence in 2012/2013. (author)

2012-08-01

353

Testing for recombinant human erythropoietin  

Science.gov (United States)

ERYTHROPOIETIN (Epo) may have effects on exercise capacity and physiological regulation beyond a simple increase in red cell mass and the associated improvement in oxygen transport (4). In the context of a larger study on this topic, Lundby and colleagues (11) also asked questions about the reliability of urine testing for recombinant human Epo (rHuEpo). They studied eight healthy male subjects during a 4-wk "loading" and 2-wk "boosting" phase of Epo use followed by a 2-wk maintenance phase. In the parent study they showed that the effects of Epo on exercise performance were confined to its impact on red cell mass and not to other physiological effects of the hormone. These results were consistent with ideas about the relationship between maximal oxygen uptake and red cell mass or total body hemoglobin that emerged in the 1950s. The findings are timely and have implications for public policy relating to the control of doping practices. In this short report a number of challenges related to urine testing for Epo are highlighted.

Joris R Delanghe (Ghent University Hospital Clinical Chemistry); Michael J Joyner (Mayo Clinic Anesthesiology)

2008-08-10

354

Effects of the oral, direct thrombin inhibitor dabigatran on five common coagulation assays.  

Science.gov (United States)

Dabigatran is an oral, reversible thrombin inhibitor that has shown promising results in large clinical trials. Laboratory monitoring is not needed but the effects on common coagulation assays are incompletely known. Dabigatran was added to plasma from healthy subjects in the concentration range 0-1,000 ?g/l and analysed using several reagents for activated thromboplastin time (APTT), prothrombin time (PT), fibrinogen, antithrombin, and activated protein C resistance. Typical trough concentrations are about 50 ?g/l, peak concentrations 100-300 ?g/l. At 100 ?g/l all APTT-results were prolonged. The concentration required to double APTT ranged between 227 and 286 ?g/l, the responses for all five reagents were similar. PT-reagents were much less affected with almost no samples above INR 1.2 at 100 ?g/l. The effect was sample dilution dependent with PT Quick type more sensitive than PT Owren type methods. If a patient on dabigatran has prolonged APTT, >90 seconds, and Quick PT INR>2 or Owren PT INR>1.5 over-dosing or accumulation of dabigatran should be considered. Two of four fibrinogen reagents underestimated the fibrinogen concentration considerably at expected peak concentration. Methods based on inhibition of thrombin over-estimated the antithrombin concentration, but not Xa-based. The APC-resistance methods over-estimated the APC-ratio, which may lead to miss-classification of factor V Leiden patients as being normal. Different coagulation assays, and even different reagents within an assay group, display variable effects at therapeutic concentrations of dabigatran. Some of these assay variations are of clinical importance, thus knowledge is needed for a correct interpretation of results. PMID:21103660

Lindahl, Tomas L; Baghaei, Fariba; Blixter, Inger Fagerberg; Gustafsson, Kerstin M; Stigendal, Lennart; Sten-Linder, Margareta; Strandberg, Karin; Hillarp, Andreas

2011-02-01

355

Inhibition of tissue factor pathway inhibitor increases the sensitivity of thrombin generation assay to procoagulant microvesicles.  

Science.gov (United States)

Patients with cancer have a seven-fold to 10-fold increased risk of developing venous thromboembolism (VTE). Circulating microvesicles could be a predictive biomarker for VTE in cancer. Thrombin generation assay (TGA) is a useful technique to detect procoagulant activity of microvesicles. However, TGA suffers from a lack of sensitivity due to the presence of tissue factor pathway inhibitor (TFPI) in plasma. The aim of the study was to improve the sensitivity of TGA to tissue factor by limiting the interference of TFPI. Serial dilutions of MDA-MB231 cells were incubated for 45 min at 37°C to generate microvesicles. Samples were then centrifuged and supernatants that contain microvesicles were used for TGA. Normal pooled plasma was incubated with inhibitor of TFPI or was diluted twice to decrease plasma level of TFPI. Lagtime was used as a surrogate marker of TGA to detect procoagulant activity of microvesicles. Inhibition of TFPI decreased twice the cell concentration needed for a significant reduction of lagtime and decreased 2.4-fold the intraassay variability. Plasma dilution had no impact on the TGA sensitivity when TGA was triggered by microvesicles derived from MDA-MB-231. Thrombin generation is a very sensitive method to study the procoagulant activity of tissue factor bearing microvesicles. The sensitivity can be increased by inhibition of TFPI with specific monoclonal antibody against its Kunitz domain I. A two times plasma dilution is an interesting cheaper alternative to study the procoagulant activity of microvesicles by TGA with a good sensitivity, especially when low plasma quantities are available. PMID:23807485

Gheldof, Damien; Mullier, François; Chatelain, Bernard; Dogné, Jean-Michel; Chatelain, Christian

2013-07-01

356

Platelet phospholipids in relation to thrombin, cholesterol, and vitamin D/sub 3/  

Energy Technology Data Exchange (ETDEWEB)

The aggregation responses of gerbil platelet suspensions to 10 uM adenosine diphosphate (ADP) and 0.2 U/mL thrombin were found to be rapid and irreversible. Bovine acid-soluble collagen (1:800 dilution) produced a characteristic long lag phase coupled with an irreversible aggregation. Indomethacin (10 uM) depressed ADP-induced aggregation but had no marked effect on thrombin-induced aggregation. Indomethacin prolonged the lag phase and reduced the rate of collagen-induced aggregation. Investigations were also conducted to evaluate the differences in the composition of platelet lipids derived from hypercholesterolemic patients and gerbils compared to controls. An increased content of both cholesterol and arachidonate-containing phospholipids was found to be associated with hypercholesterolemia. The pro-aggregating potential of the vitamin D/sub 3/ metabolites, 1,25-dihydroxycholecalciferol (1,25-DHCC) and 25-hydroxycholecalciferol, was tested in human platelets. In addition, the effects of metabolites on phospholipid turnover was studied. At a concentration of 0.04 ug/uL, 25-HCC and 1,25-DHCC, but not vitamin D/sub 3/, resulted in marked aggregation using washed human platelet suspensions. By pre-labelling individual phosphilipds in human platelets with (/sup 3/H)glycerol, it was observed, that 25-HCC and 1,25-DHCC were (/sup 3/H)glycerol, it was observed, that 25-HCC and 1,25-DHCC were capable of promoting the degradation (/sup 3/H)PI and accumulation of (H)diacylglycerol.

Agwu, D.C.E.

1985-01-01

357

Topical agents in burn care  

Directory of Open Access Journals (Sweden)

Full Text Available Introduction Understanding of fluid shifts and recognition of the importance of early and appropriate fluid replacement therapy have significantly reduced mortality in the early post burn period. After the bum patient successfully passes the resuscitation period, the burn wound represents the greatest threat to survival. History Since the dawn of civilization, man has been trying to find an agent which would help burn wounds heal, and at the same time, not harm general condition of the injured. It was not until the XX century, after the discovery of antibiotics, when this condition was fulfilled. In 1968, combining silver and sulfadiazine, fox made silver-sulfadiazine, which is a 1% hydro-soluble cream and a superior agent in topical treatment of burns today. Current topical agents None of the topical antimicrobial agents available today, alone or combined, have the characteristics of ideal prophylactic agents, but they eliminate colonization of burn wound, and invasive infections are infrequent. With an excellent spectrum of activity, low toxicity, and ease of application with minimal pain, silver-sulfadiazine is still the most frequently used topical agent. Conclusion The incidence of invasive infections and overall mortality have been significantly reduced after introduction of topical burn wound antimicrobial agents into practice. In most burn patients the drug of choice for prophylaxis is silver sulfadiazine. Other agents may be useful in certain clinical situations.

Mom?ilovi? Dragan

2002-01-01

358

RNA-seq analysis of transcriptomes in thrombin-treated and control human pulmonary microvascular endothelial cells.  

Science.gov (United States)

The characterization of gene expression in cells via measurement of mRNA levels is a useful tool in determining how the transcriptional machinery of the cell is affected by external signals (e.g. drug treatment), or how cells differ between a healthy state and a diseased state. With the advent and continuous refinement of next-generation DNA sequencing technology, RNA-sequencing (RNA-seq) has become an increasingly popular method of transcriptome analysis to catalog all species of transcripts, to determine the transcriptional structure of all expressed genes and to quantify the changing expression levels of the total set of transcripts in a given cell, tissue or organism. RNA-seq is gradually replacing DNA microarrays as a preferred method for transcriptome analysis because it has the advantages of profiling a complete transcriptome, providing a digital type datum (copy number of any transcript) and not relying on any known genomic sequence. Here, we present a complete and detailed protocol to apply RNA-seq to profile transcriptomes in human pulmonary microvascular endothelial cells with or without thrombin treatment. This protocol is based on our recent published study entitled "RNA-seq Reveals Novel Transcriptome of Genes and Their Isoforms in Human Pulmonary Microvascular Endothelial Cells Treated with Thrombin," in which we successfully performed the first complete transcriptome analysis of human pulmonary microvascular endothelial cells treated with thrombin using RNA-seq. It yielded unprecedented resources for further experimentation to gain insights into molecular mechanisms underlying thrombin-mediated endothelial dysfunction in the pathogenesis of inflammatory conditions, cancer, diabetes, and coronary heart disease, and provides potential new leads for therapeutic targets to those diseases. The descriptive text of this protocol is divided into four parts. The first part describes the treatment of human pulmonary microvascular endothelial cells with thrombin and RNA isolation, quality analysis and quantification. The second part describes library construction and sequencing. The third part describes the data analysis. The fourth part describes an RT-PCR validation assay. Representative results of several key steps are displayed. Useful tips or precautions to boost success in key steps are provided in the Discussion section. Although this protocol uses human pulmonary microvascular endothelial cells treated with thrombin, it can be generalized to profile transcriptomes in both mammalian and non-mammalian cells and in tissues treated with different stimuli or inhibitors, or to compare transcriptomes in cells or tissues between a healthy state and a disease state. PMID:23426025

Cheranova, Dilyara; Gibson, Margaret; Chaudhary, Suman; Zhang, Li Qin; Heruth, Daniel P; Grigoryev, Dmitry N; Ye, Shui Qing

2013-01-01

359

Special Topics in Water Science (Water Pollution)  

Science.gov (United States)

... A Teachers Contact Back to previous page Special Topics in Water Science Our Special Topics section lets you explore other water-science topic areas, such as water quality, urbanization and water, ...

360

Thrombin induces ICAM-1 expression in human lung epithelial cells via c-Src/PDGFR/PI3K/Akt-dependent NF-?B/p300 activation.  

Science.gov (United States)

Up-regulation of ICAM-1 (intercellular adhesion molecule-1) is frequently implicated in lung inflammation and lung diseases, such as IPF (idiopathic pulmonary fibrosis). Thrombin has been shown to play a key role in inflammation via the induction of adhesion molecules, which then causes lung injury. However, the mechanisms underlying thrombin-induced ICAM-1 expression in HPAEpiCs (human pulmonary alveolar epithelial cells) remain unclear. In the present study, we have shown that thrombin induced ICAM-1 expression in HPAEpiCs. Pre-treatment with the inhibitor of thrombin [PPACK (D-Phe-Pro-Arg-chloromethyl ketone)], c-Src (PP1), PDGFR (platelet-derived growth factor receptor) (AG1296), PI3K (phosohinositide 3-kinase) (LY294002), NF-?B (nuclear factor ?B) (Bay11-7082) or p300 (GR343) and transfection with siRNAs of c-Src, PDGFR, Akt, p65 and p300 markedly reduced thrombin-induced ICAM-1 expression and monocyte adherence to HPAEpiCs challenged with thrombin. In addition, we established that thrombin stimulated the phosphorylation of c-Src, PDGFR, Akt and p65, which were inhibited by pre-treatment with their respective inhibitors PP1, AG1296, LY294002 or Bay11-7082. In addition, thrombin also enhanced Akt and NF-?B translocation from the cytosol to the nucleus, which was reduced by PP1, AG1296 or LY294002. Thrombin induced NF-?B promoter activity and the formation of the p65-Akt-p300 complex, which were inhibited by AG1296, LY294002 or PP1. Finally, we have shown that thrombin stimulated in vivo binding of p300, Akt and p65 to the ICAM-1 promoter, which was reduced by AG1296, LY294002, SH-5 or PP1. These results show that thrombin induced ICAM-1 expression and monocyte adherence via a c-Src/PDGFR/PI3K/Akt/NF-?B-dependent pathway in HPAEpiCs. Increased understanding of the signalling mechanisms underlying ICAM-1 gene regulation will create opportunities for the development of anti-inflammatory therapeutic strategies. PMID:24506791

Cheng, Shin-Ei; Lee, I-Ta; Lin, Chih-Chung; Hsiao, Li-Der; Yang, Chuen-Mao

2014-08-01

 
 
 
 
361

The use of recombinant human erythropoietin and cultured epithelial autografts in a Jehovah's Witness with a major thermal injury.  

Science.gov (United States)

Haemostatic debridement, recombinant-human erythropoietin and cultured epithelial autografts have been used successfully in a Jehovah's Witness with a major burn injury. Tourniquet ischaemia complemented by a topical haemostatic agent minimized excisional blood loss, while recombinant-human erythropoietin accelerated erythropoiesis, thereby correcting postburn anaemia. Cultured epithelial autografts provided coverage of the granulating wounds without creating donor sites. PMID:8198726

Moghtader, J C; Edlich, R F; Mintz, P D; Zachmann, G C; Himel, H N

1994-04-01

362

Experiência inicial com o uso de adesivo tissular contendo trombina para tratamento do pseudo-aneurisma femoral / Treatment of femoral pseudoaneurysm with thrombin tissue adhesive: initial experience  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese O pseudo-aneurisma (PSA) após cateterização femoral tem sido diagnosticado com regularidade em serviços com grande movimento de intervenções percutâneas, com incidência variando de 0,05 a 6%. PSA femorais pequenos podem ser acompanhados até a resolução espontânea. As opções de tratamento são: compre [...] ssão guiada por ultra-som, injeção de trombina para trombose do PSA e tratamento cirúrgico. A injeção percutânea de trombina tem a vantagem de ser um procedimento indolor e rápido. Podem ser utilizados trombina isolada ou preparados contendo trombina associada a fibrinogênio e fatores de coagulação. A experiência inicial dos autores de cinco casos tratados com injeção de adesivo tissular contendo trombina mostrou resultado satisfatório em quatro; um caso necessitou tratamento cirúrgico. Não houve sucesso com uso isolado de trombina humana, porém, ocorreu trombose imediata após injeção de preparado de trombina associada a fibrinogênio/fator XIII. Neste artigo, são discutidas as opções de tratamento dos PSA femorais e a técnica do uso de trombina percutânea. Abstract in english Pseudoaneurysms caused by femoral artery catheterization have been regularly diagnosed in medical units with a great number of percutaneous interventions, with a documented incidence between 0.05 and 6%. Small femoral pseudoaneurysms undergo spontaneous resolution. Treatment options are: ultrasound- [...] guided compression, thrombin injection to induce pseudoaneurysm thrombosis and surgical treatment. Percutaneous thrombin injection has the advantage of being a fast and painless procedure. Both isolated thrombin and thrombin preparations with fibrinogen and coagulation factors can be used. The authors' initial experience with five cases treated with thrombin tissue adhesive showed successful results in four; one case required surgery. There was no success with isolated human thrombin, but immediate thrombosis was achieved after injection of thrombin associated to fibrinogen and factor XIII. In this article, the treatment options for femoral pseudoaneurysms and the technique of percutaneous thrombin are discussed.

Daniel Mendes, Pinto; José Olimpio, Dias Júnior; Bernardo Lopes Cançado, Fonseca; Rodrigo Daniel, Moreialvar; Leonardo Ghizoni, Bez; Caetano de Sousa, Lopes.

363

Experiência inicial com o uso de adesivo tissular contendo trombina para tratamento do pseudo-aneurisma femoral Treatment of femoral pseudoaneurysm with thrombin tissue adhesive: initial experience  

Directory of Open Access Journals (Sweden)

Full Text Available O pseudo-aneurisma (PSA após cateterização femoral tem sido diagnosticado com regularidade em serviços com grande movimento de intervenções percutâneas, com incidência variando de 0,05 a 6%. PSA femorais pequenos podem ser acompanhados até a resolução espontânea. As opções de tratamento são: compressão guiada por ultra-som, injeção de trombina para trombose do PSA e tratamento cirúrgico. A injeção percutânea de trombina tem a vantagem de ser um procedimento indolor e rápido. Podem ser utilizados trombina isolada ou preparados contendo trombina associada a fibrinogênio e fatores de coagulação. A experiência inicial dos autores de cinco casos tratados com injeção de adesivo tissular contendo trombina mostrou resultado satisfatório em quatro; um caso necessitou tratamento cirúrgico. Não houve sucesso com uso isolado de trombina humana, porém, ocorreu trombose imediata após injeção de preparado de trombina associada a fibrinogênio/fator XIII. Neste artigo, são discutidas as opções de tratamento dos PSA femorais e a técnica do uso de trombina percutânea.Pseudoaneurysms caused by femoral artery catheterization have been regularly diagnosed in medical units with a great number of percutaneous interventions, with a documented incidence between 0.05 and 6%. Small femoral pseudoaneurysms undergo spontaneous resolution. Treatment options are: ultrasound-guided compression, thrombin injection to induce pseudoaneurysm thrombosis and surgical treatment. Percutaneous thrombin injection has the advantage of being a fast and painless procedure. Both isolated thrombin and thrombin preparations with fibrinogen and coagulation factors can be used. The authors' initial experience with five cases treated with thrombin tissue adhesive showed successful results in four; one case required surgery. There was no success with isolated human thrombin, but immediate thrombosis was achieved after injection of thrombin associated to fibrinogen and factor XIII. In this article, the treatment options for femoral pseudoaneurysms and the technique of percutaneous thrombin are discussed.

Daniel Mendes Pinto

2006-03-01

364

Dabigatran, a direct thrombin inhibitor, blocks differentiation of normal fibroblasts to a myofibroblast phenotype and demonstrates anti-fibrotic effects on scleroderma lung fibroblasts  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Myofibroblasts are the principal mesenchymal cells responsible for tissue remodeling, collagen deposition, and the restrictive nature of lung parenchyma associated with pulmonary fibrosis. We previously reported that thrombin activates protease-activated receptor (PAR)-1 thereby inducing normal lung fibroblasts to differentiate to a myofibroblast phenotype resembling scleroderma lung myofibroblasts. Here we demonstrate that the thrombin inhibitor dabigatran inhibits in a dose-dependant manner...

Bogatkevich, Galina S.; Ludwicka-bradley, Anna; Silver, Richard M.

2009-01-01

365

The protease thrombin is an endogenous mediator of hippocampal neuroprotection against ischemia at low concentrations but causes degeneration at high concentrations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have considered the extracellular serine protease thrombin and its receptor as endogenous mediators of neuronal protection against brain ischemia. Exposure of gerbils to prior mild ischemic insults, here two relatively short-lasting occlusions (2 min) of both common carotid arteries applied at 1-day intervals 2 days before a severe occlusion (6 min), caused a robust ischemic tolerance of hippocampal CA1 neurons. This resistance was impaired if the specific thrombin inhibitor hirudin was in...

Striggow, Frank; Riek, Monika; Breder, Jo?rg; Henrich-noack, Petra; Reymann, Klaus G.; Reiser, Georg

2000-01-01

366

Thrombin Activates AMP-Activated Protein Kinase in Endothelial Cells via a Pathway Involving Ca2+/Calmodulin-Dependent Protein Kinase Kinase ?  

Digital Repository Infrastructure Vision for European Research (DRIVER)

AMP-activated protein kinase (AMPK) is a sensor of cellular energy state in response to metabolic stress and other regulatory signals. AMPK is controlled by upstream kinases which have recently been identified as LKB1 or Ca2+/calmodulin-dependent protein kinase kinase ? (CaMKK?). Our study of human endothelial cells shows that AMPK is activated by thrombin through a Ca2+-dependent mechanism involving the thrombin receptor protease-activated receptor 1 and Gq-protein-mediated phospholipase C...

Stahmann, Nadine; Woods, Angela; Carling, David; Heller, Regine

2006-01-01

367

Selected topics in nuclear structure  

International Nuclear Information System (INIS)

The Fourth International Conference on selected topics in nuclear structure was held at Dubna in July 1994 on recent experimental and theoretical investigations in nuclear structure. Topics discussed were the following: nuclear structure at low-energy excitations (collective quasiparticle phenomena, proton-neutron interactions, microscopic and phenomenological theories of nuclear structure; nuclear structure studies with charged particles. heavy ions, neutrons and photons; nuclei at high angular momenta and superdeformation, structure and decay properties of giant resonances, charge-exchange resonances and ?-decay; semiclassical approach of large amplitude collective motion and structure of hot nuclei

1994-07-05

368

Topics in Complementary and Alternative Therapies (PDQ)  

Science.gov (United States)

Topics in Complementary and Alternative Therapies (PDQ®) Patient Version Health Professional Version Last Modified: 06/13/2014 Topics in Complementary and Alternative Therapies (PDQ®) Overview Acupuncture ...

369

Hypotonicity and thrombin activate taurine efflux in BC3H1 and C2C12 myoblasts that is down regulated during differentiation.  

Science.gov (United States)

The efflux of organic osmolytes such as taurine is an important mechanism by which cells regulate their volume. The effects of hypotonicity and thrombin on taurine efflux were studied in BC3H1 and C2C12 cells, two mouse myoblastic cell lines that can be induced to differentiate with serum deprivation. In proliferating cultures of both cell types preloaded with [3H]taurine, exposure to 27% hypotonicity activated a 10- to 20-fold increase in [3H]taurine efflux (Jtau). This effect was blocked by the C1- channel inhibitors NPPB and flufenamic acid. Thrombin and the thrombin receptor agonist SFLLRN also activated Jtau that was abolished by NPPB and flufenamic acid. Together, hypotonicity and thrombin synergistically activated Jtau. In differentiated myocytes, the effect of thrombin was abolished, while that of hypotonicity was significantly reduced. These results suggest that (i) hypotonicity and thrombin activate taurine-permeable anion channels in BC3H1 and C2C12 cells, and (ii) these anion channels may be involved in cell proliferation. PMID:9125155

Manolopoulos, V G; Droogmans, G; Nilius, B

1997-03-01

370

?-thrombin-induced inositol phosphate formation in G0-arrested and cycling hamster lung fibroblasts: evidence for a protein kinase C-mediated desensitization response  

International Nuclear Information System (INIS)

In resting Chinese hamster fibroblasts (CCL39) ?-thrombin rapidly induces the breakdown of phosphoinositides. Accumulation of inositol phosphates (IP), measured in the presence of Li+, is detectable within 5s (seconds) of thrombin stimulation. Formation of inositol tris- and bisphosphates slightly precedes that of inositol monophosphate, indicating that thrombin activates primarily the phospholipase C-mediated generation of inositol trisphosphate from phosphatidylinositol 4,5-bisphosphate. Initial rates of IP production increase with thrombin concentration, with no apparent saturability over the range 10-4-10 U/ml. Thrombin-induced phosphoinositide hydrolysis rapidly desensitizes (t/sub 1/2/ > 5 min), but a residual activity, corresponding to about 10% of the initial stimulation is sustained for at least 9 h, in contrast with the undetectable activity of G0-arrested cells. This apparent desensitization may be due to a feedback regulation by protein kinase C, since pretreatment with the phorbol ester 12-O-tetradecanoyl phorbol 13-acetate (TPA) markedly inhibits (by up to 70%) subsequent thrombin-induced inositol phosphate formation. This up regulation was found maximal in A51, a very well growth-arrested CCL39 derivative,and reduced or virtually abolished in two tumoral and growth factor-relaxed derivatives of CCL39. Although preliminary, this observation suggests that a persistent activation of phosphatidyl inositol breakdown might operate in variants selected for autonomous growth

1986-01-01

371

Secretory products from thrombin-stimulated human platelets exert an inhibitory effect on NK-cytotoxic activity.  

DEFF Research Database (Denmark)

We have investigated the interaction between human platelets and the NK-system, with special emphasis on the action of secretory products from platelets in an NK assay with 51Cr-labelled K562 as target cells. Supernatants from thrombin-stimulated platelets added to the NK assay consistently decreased the NK-cytotoxicity by 40% +/- 4.3%, indicating the existence of secreted products from platelets as a source of NK-inhibiting substances. In contrast, no direct cytotoxic effect of these secretory products on the target cells (K562) was seen. Thus, normal human platelets, when stimulated with thrombin, are capable of secreting different, yet undefined factors, which significantly inhibit NK activity in vitro. The results also suggest that the role of products from contaminating in vitro activated platelets should be borne in mind when performing conventional NK assays. Udgivelsesdato: 1986-Oct

Skov Madsen, P; Hokland, P

1987-01-01

372

Selected topics in nuclear structure  

International Nuclear Information System (INIS)

19. winter school in Zakopane was devoted to selected topics in nuclear structure such as: production of spin resonances, heavy ions reactions and their applications to the investigation of high spin states, octupole deformations, excited states and production of new elements etc. The experimental data are ofen compared with theoretical predictions. Report contains 28 papers. (M.F.W.)

1984-04-03

373

Seven topics in perturbative QCD  

International Nuclear Information System (INIS)

The following topics of perturbative QCD are discussed: (1) deep inelastic scattering; (2) higher order corrections to e+e- annihilation, to photon structure functions and to quarkonia decays; (3) higher order corrections to fragmentation functions and to various semi-inclusive processes; (4) higher twist contributions; (5) exclusive processes; (6) transverse momentum effects; (7) jet and photon physics

1980-06-13

374

Seven topics in perturbative QCD  

Energy Technology Data Exchange (ETDEWEB)

The following topics of perturbative QCD are discussed: (1) deep inelastic scattering; (2) higher order corrections to e/sup +/e/sup -/ annihilation, to photon structure functions and to quarkonia decays; (3) higher order corrections to fragmentation functions and to various semi-inclusive processes; (4) higher twist contributions; (5) exclusive processes; (6) transverse momentum effects; (7) jet and photon physics.

Buras, A.J.

1980-09-01

375

Seven topics in perturbative QCD  

International Nuclear Information System (INIS)

The following topics of perturbative QCD are discussed: (1) Deep inelastic scattering; (2) Higher order corrections to e+e- annihilation, to photon structure functions and to quarkonia decays; (3) Higher order corrections to fragmentation functions and to various semi-inclusive processes; (4) Higher twist contributions; (5) Exclusive processes; (6) p(transverse) effects; (7) Jet and photon physics. (Auth.)

1981-05-01

376

Topic Map for Authentic Travel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

E-business is a new trend in Internet use. Authentic travel is an approach to travel and travel business which helps the traveler experience what is authentic in the travel destination. But how can the traveler find those small authentic spots and organize them together to compose a vacation? E-business techniques, combined withTopic Maps, can help.

Wandsvik, Atle; Zare, Mehdi

2007-01-01

377

Benchmark Dose Modeling - Advanced Topics  

Science.gov (United States)

Benchmark Dose Modeling – Advanced Topics Course The objectives of this full-day course are to provide participants with training on how to use the U.S. Environmental Protection Agency’s (EPA) Benchmark Dose Modeling Software (BMDS) and related software programs to fa...

378

Thrombin activatable fibrinolysis inhibitor binds to Streptococcus pyogenes by interacting with collagen-like surface proteins A and B.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Regulation of proteolysis is a critical element of the host immune system and plays an important role in the induction of pro- and anti-inflammatory reactions in response to infection. Some bacterial species take advantage of these processes and recruit host proteinases to their surface in order to counteract the host attack. Here we show that Thrombin-activatable Fibrinolysis Inhibitor (TAFI), a zinc-dependent procarboxypeptidase, binds to the surface of group A streptococci of an M41 seroty...

Pa?hlman, Lisa; Marx, Pauline F.; Mo?rgelin, Matthias; Lukomski, Slawomir; Meijers, Joost C. M.; Herwald, Heiko

2007-01-01

379

Transarterial Thrombin Injection Secured with an Embolic Protection Device as a Treatment for a Superior Mesenteric Artery Pseudoaneurysm  

International Nuclear Information System (INIS)

A pseudoaneurysm of the superior mesenteric artery (SMA) is a rare and life-threatening condition of various etiology. Even unruptured it can cause severe health problems or death. We report a 71-year-old male with a SMA pseudoaneurysm who was successfully treated with a transarterial thrombin injection secured with an embolic protection device used in carotid angioplasty. To our knowledge, this is the first case of a SMA pseudoaneurysm treated by this method.

2011-02-01

380

Coagulation Proteins Influencing Global Coagulation Assays in Cirrhosis: Hypercoagulability in Cirrhosis Assessed by Thrombomodulin-Induced Thrombin Generation Assay  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Background. Liver disease is accompanied by profound hemostatic disturbances. We investigated the influences of pro- and anticoagulation factors on global coagulation tests including prothrombin time (PT), activated partial thromboplastin time (aPTT), and thrombin generation assay (TGA) in cirrhosis. We also investigated whether cirrhotic patients exhibit hypo- or hypercoagulability using the TGA. Methods. The TGA was performed on a calibrated automated thrombogram, given lag time, endogenous...

Youngwon, Nam; Kim, Ji-eun; Lim, Hae Sook; Han, Kyou-sup; Kim, Hyun Kyung

2013-01-01

 
 
 
 
381

MEASUREMENT OF FIBRINOGEN CONCENTRATION IN THE PLASMA OF DOGS: A COMPARISON BETWEEN HEAT PRECIPITATION AND MODIFIED THROMBIN CLOTTING TIME METHOD  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fibrinogen is a glycoprotein that plays a key role in blood clotting and is also a non-specific indicator of inflammation. The most widely used techniques for measuring plasma fibrinogen concentration include heat precipitation (Millarâ??s technique) and modified thrombin clotting time (Clauss method). Both techniques have been automated in a haematology analyzer (QBC-Vet Autoreader®, IDEXX; Millarâ??s technique) and in a newly developed semi-automatic mechanical and ...

2013-01-01

382

Is there any role of thrombin activatable fibrinolysis inhibitor in the development of a hypercoagulable state in gastric cancer  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background The purpose of this study was to investigate plasma levels of thrombin activatable fibrinolysis inhibitor (TAFI) and TAFI’s relationship with coagulation markers (prothrombin fragment 1?+?2) in gastric cancer patients. Methods Thirty-three patients with gastric adenocarcinoma and 29 healthy control subjects were prospectively enrolled in the study. Patients who had a history of secondary malignancy, thrombosis related disease, oral cont...

2012-01-01

383

NADPH oxidases regulate CD44 and hyaluronic acid expression in thrombin-treated vascular smooth muscle cells and in atherosclerosis.  

Science.gov (United States)

The intracellular signaling events by which NADPH oxidase-generated reactive oxygen species (ROS) modulate vascular smooth muscle cell (VSMC) function and atherogenesis are yet to be entirely elucidated. We previously demonstrated that NADPH oxidase deficiency decreased atherosclerosis in apoE(-/-) mice and identified adhesion protein CD44 as an important ROS-sensitive gene expressed in VSMC and atherosclerotic lesions. Here, we examined the molecular mechanisms by which NADPH oxidase-generated ROS regulate the expression of CD44 and its principal ligand, hyaluronan (HA), and how CD44-HA interaction affects VSMC proliferation and migration and inflammatory gene expression in apoE(-/-) mice aortas. Thrombin-induced CD44 expression is mediated by transcription factor AP-1 in a NADPH oxidase-dependent manner. NADPH oxidase-mediated ROS generation enhanced thrombin-induced HA synthesis, and hyaluronan synthase 2 expression in VSMC. Hyaluronidase, which generates low molecular weight HA (LMW-HA), is induced in VSMC in a NADPH oxidase-dependent manner and LMW-HA stimulated ROS generation and cell proliferation in wild-type but not p47(phox-/-) VSMC, effects that were enhanced by thrombin pretreatment. Haptotactic VSMC migration toward HA was increased by thrombin in a CD44-dependent manner. HA expression in atherosclerotic lesions and plasma-soluble CD44 and HA levels were higher in apoE(-/-) compared with apoE(-/-)/p47(phox-/-) mice. HA-regulated pro-inflammatory gene expression was higher in apoE(-/-) than apoE(-/-)/p47(phox-/-) mouse aortas. GKT136901, a specific inhibitor of Nox1- and Nox4-containing NADPH oxidase activity, attenuated ROS generation and atherosclerosis and decreased CD44 and HA expression in atherosclerotic lesions. Together, these data suggest that increased CD44 and HA expression and CD44-HA-dependent gene regulation may play a role in atherosclerosis stimulated by NADPH oxidase activation. PMID:20558727

Vendrov, Aleksandr E; Madamanchi, Nageswara R; Niu, Xi-Lin; Molnar, Kimberly C; Runge, Mason; Szyndralewiez, Cédric; Page, Patrick; Runge, Marschall S

2010-08-20

384

NADPH Oxidases Regulate CD44 and Hyaluronic Acid Expression in Thrombin-treated Vascular Smooth Muscle Cells and in Atherosclerosis*  

Science.gov (United States)

The intracellular signaling events by which NADPH oxidase-generated reactive oxygen species (ROS) modulate vascular smooth muscle cell (VSMC) function and atherogenesis are yet to be entirely elucidated. We previously demonstrated that NADPH oxidase deficiency decreased atherosclerosis in apoE?/? mice and identified adhesion protein CD44 as an important ROS-sensitive gene expressed in VSMC and atherosclerotic lesions. Here, we examined the molecular mechanisms by which NADPH oxidase-generated ROS regulate the expression of CD44 and its principal ligand, hyaluronan (HA), and how CD44-HA interaction affects VSMC proliferation and migration and inflammatory gene expression in apoE?/? mice aortas. Thrombin-induced CD44 expression is mediated by transcription factor AP-1 in a NADPH oxidase-dependent manner. NADPH oxidase-mediated ROS generation enhanced thrombin-induced HA synthesis, and hyaluronan synthase 2 expression in VSMC. Hyaluronidase, which generates low molecular weight HA (LMW-HA), is induced in VSMC in a NADPH oxidase-dependent manner and LMW-HA stimulated ROS generation and cell proliferation in wild-type but not p47phox?/? VSMC, effects that were enhanced by thrombin pretreatment. Haptotactic VSMC migration toward HA was increased by thrombin in a CD44-dependent manner. HA expression in atherosclerotic lesions and plasma-soluble CD44 and HA levels were higher in apoE?/? compared with apoE?/?/p47phox?/? mice. HA-regulated pro-inflammatory gene expression was higher in apoE?/? than apoE?/?/p47phox?/? mouse aortas. GKT136901, a specific inhibitor of Nox1- and Nox4-containing NADPH oxidase activity, attenuated ROS generation and atherosclerosis and decreased CD44 and HA expression in atherosclerotic lesions. Together, these data suggest that increased CD44 and HA expression and CD44-HA-dependent gene regulation may play a role in atherosclerosis stimulated by NADPH oxidase activation.

Vendrov, Aleksandr E.; Madamanchi, Nageswara R.; Niu, Xi-Lin; Molnar, Kimberly C.; Runge, Mason; Szyndralewiez, Cedric; Page, Patrick; Runge, Marschall S.

2010-01-01

385

SUMO Wrestles with Recombination  

Directory of Open Access Journals (Sweden)

Full Text Available DNA double-strand breaks (DSBs comprise one of the most toxic DNA lesions, as the failure to repair a single DSB has detrimental consequences on the cell. Homologous recombination (HR constitutes an error-free repair pathway for the repair of DSBs. On the other hand, when uncontrolled, HR can lead to genome rearrangements and needs to be tightly regulated. In recent years, several proteins involved in different steps of HR have been shown to undergo modification by small ubiquitin-like modifier (SUMO peptide and it has been suggested that deficient sumoylation impairs the progression of HR. This review addresses specific effects of sumoylation on the properties of various HR proteins and describes its importance for the homeostasis of DNA repetitive sequences. The article further illustrates the role of sumoylation in meiotic recombination and the interplay between SUMO and other post-translational modifications.

Lumír Krej?í

2012-07-01

386

Exploding foil recombination laser  

International Nuclear Information System (INIS)

In addition to experiments using the collisional-excitation approach to a soft x-ray laser, the authors tested a recombination-pumped laser scheme. Intense (I/sub L/ approx. 2 x 1014 W/cm2) 0.53-?m light of 100- to 200-ps duration from the Novette laser was used to fully ionize a magnesium exploding-foil target. After the peak of the laser pulse, the plasma cooled rapidly due to expansion, electron conduction, and radiation. In the regime of high electron density (approx. 1020 cm-3) and low electron temperature (approx. 100 eV), three-body recombination preferentially populates the upper levels of the hydrogen-like magnesium ion. The population of the lower levels is depleted by fast radiative decay. This process can result in a population inversion on the n = 4 to 3, 130-A transition

1985-06-01

387

Recombinant Human Enterovirus 71  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Two human enterovirus 71 (HEV71) isolates were identified from hand, foot and mouth disease patients with genome sequences that had high similarity to HEV71 (>93%) at 5´ UTR, P1, and P2 and coxsackievirus A16 (CV-A16, >85%) at P3 and 3´UTR. Intertypic recombination is likely to have occurred between HEV71 and CV-A16 or an as-yet to be described CV-A16-like virus.

2004-01-01

388

A Simplified Recombinant PSO  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Simplified forms of the particle swarm algorithm are very beneficial in contributing to understanding how a particle swarm optimization (PSO) swarm functions. One of these forms, PSO with discrete recombination, is extended and analyzed, demonstrating not just improvements in performance relative to a standard PSO algorithm, but also significantly different behavior, namely, a reduction in bursting patterns due to the removal of stochastic components from the update equations.

Dan Bratton; Tim Blackwell

2008-01-01

389

Radiative recombination rate coefficients  

International Nuclear Information System (INIS)

Radiative recombination rate coefficients obtained using the nonrelativistic dipole result of Stobbe for the RR cross section are compared to other nonrelativistic approaches. A good agreement is found with widely used formulas. The RR rate coefficients can be calculated for different beam temperatures and for arbitrary nl sublevels up to high Rydberg states. The computation technique used allows us a fast evaluation of the dipole matrix elements without any additional approximation. (orig.)

2000-01-01

390

Ultrasound-guided thrombin injection for the treatment of an iatrogenic hepatic artery pseudoaneurysm: a case report  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Introduction Percutaneous transhepatic portal embolization is often performed to expand the indications for hepatic resection. Various etiologies of hepatic artery pseudoaneurysm have been reported, but regardless of the etiology, hepatic artery pseudoaneurysm is usually managed with an endovascular approach or open surgery, depending on the location and clinical symptomatology. However, it is difficult to manage hepatic artery pseudoaneurysm after percutaneous transhepatic portal embolization, since embolization of the hepatic artery may cause hepatic infarction Case presentation A 58-year-old Japanese man with hilar bile duct cancer underwent percutaneous transhepatic portal embolization to expand the indication for hepatic resection. Two days after percutaneous transhepatic portal embolization, our patient suddenly complained of abdominal pain. Contrast-enhanced computed tomography confirmed a pseudoaneurysm arising from a segmental branch of his right hepatic artery. Since embolization of the hepatic arterial branches may cause hepatic infarction, ultrasound-guided thrombin injection therapy was successfully performed for the pseudoaneurysm. Conclusion We performed a thrombin injection instead of arterial embolization to avoid hepatic infarction. The rationale of this choice may be insufficient. However, ultrasound-guided percutaneous thrombin injection therapy may be considered as an alternative to percutaneous transarterial embolization or surgical intervention for an iatrogenic hepatic artery pseudoaneurysm.

Sofue Ketaro

2011-10-01

391

Effect of thrombin and endotoxin on the in vivo metabolism of antithrombin III (AT III) in dogs  

International Nuclear Information System (INIS)

Effect of thrombin and endotoxin on the metabolism of I-125-labelled canine AT III was studied in mongrel dogs. Under control condition, mean total amount of intravascular AT III with standard deviation was 23.4 +/- 2.4 mg/kg, plasma half life of i.v. injected I-125-AT III was 1.7 +/- 0.2 days, and the fractional catabolic flux (j3x) was 16.3 +/- 1.6 mg/kg/day. The total amount of intra- and extra-vascular AT III was 36.0 +/- 0.34 mg/kg. Neither a 3 hour infusion of a small dose (30 units/kg/hr) of thrombin nor i.v. injection of a large amount of thrombin (5,000-15,000 units/day) with heparin significantly affected AT III metabolism except for a transient decrease in AT III concentration in the latter case, although decrease in plasma fibrinogen concentration and platelet count was observed in both cases. Two injections with 200 micrograms/kg of endotoxin resulted in an evident acceleration of AT III metabolism with significant decrease in the plasma AT III, fibrinogen concentrations and platelet count. More marked changes in AT III metabolism were induced by a single infusion with 1 mg/kg of endotoxin. Changes in hemostatic system coincided with those observed in DIC

1985-11-01

392

Direct detection of thrombin binding to 8-bromodeoxyguanosine-modified aptamer: effects of modification on affinity and kinetics.  

Science.gov (United States)

The affinity of an 8-bromodeoxyguanosine- (8-BrdG-) substituted thrombin-binding aptamer (TBA-Br), which has the 1st and 10th guanosine residues replaced with 8-BrdG, was estimated using reflectometric interference spectroscopy (RIfS). When comparing TBA-Br with unmodified TBA (TBA-H), it was demonstrated that the modification effectively improved the affinity of TBA; dissociation constants (K(D)) of TBA-H and TBA-Br were 45.4?nM and 1.99?nM, respectively. These values, which were obtained by direct observation of thrombin binding using RIfS, have the same order of magnitude as those obtained in our previous study utilizing conformational changes in TBA to detect thrombin binding, thus confirming the validity of the obtained K(D) values. RIfS measurements also revealed that the 8-BrdG modification resulted in a lower dissociation rate constant (k(d)), which suggests that the enhancement of affinity can be attributed to the stabilization of the G-quadruplex structure on introduction of 8-BrdG. PMID:21941628

Goji, Shou; Matsui, Jun

2011-01-01

393

A sensitive electrochemical aptasensor based on water soluble CdSe quantum dots (QDs) for thrombin determination  

Energy Technology Data Exchange (ETDEWEB)

A novel aptamer biosensor with easy operation and good sensitivity, specificity, stability and reproducibility was developed by immobilizing the aptamer on water soluble CdSe quantum dots (QDs) modified on the top of the glassy carbon electrode (GCE). Methylene blue (MB) was intercalated into the aptamer sequence and used as an electrochemical marker. CdSe QDs improved the electrochemical signal because of their larger surface area and ion centers of CdSe QDs may also had a major role on amplifying the signal. The higher ion concentration caused more combination of aptamer which caused larger signal. The thrombin was detected by differential pulse voltammetry (DPV) quantitatively. Under optimal conditions, the two linear ranges were obtained from 3 to 13 {mu}g mL{sup -1} and from 14 to 31 {mu}g mL{sup -1}, respectively. The detection limit was 0.08 {mu}g mL{sup -1} at 3{sigma}. The constructed biosensor had better responses compared with that in the absence of the CdSe QDs immobilizing. The control experiment was also carried out by using BSA, casein and IgG in the absence of thrombin. The results showed that the aptasensor had good specificity, stability and reproducibility to the thrombin. Moreover, the aptasensor could be used for detection of real sample with consistent results in comparison with those obtained by fluorescence method which could provide a promising platform for fabrication of aptamer based biosensors.

Li Yanfen; Han Min [Jiangsu Laboratory of New Power Batteries, Jiangsu Key Laboratory of Biofuctional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097 (China); Bai Hongyan [Jiangsu Laboratory of New Power Batteries, Jiangsu Key Laboratory of Biofuctional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097 (China); College of Biological and Chemical Engineering, Jiaxing College, Jiaxing 314001 (China); Wu Yong [Jiangsu Laboratory of New Power Batteries, Jiangsu Key Laboratory of Biofuctional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097 (China); Dai Zhihui, E-mail: daizhihuii@njnu.edu.cn [Jiangsu Laboratory of New Power Batteries, Jiangsu Key Laboratory of Biofuctional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097 (China); Bao Jianchun, E-mail: baojianchun@njnu.edu.cn [Jiangsu Laboratory of New Power Batteries, Jiangsu Key Laboratory of Biofuctional Materials, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210097 (China)

2011-08-01

394

Anti-thrombin III, Protein C, and Protein S deficiency in acute coronary syndrome  

Directory of Open Access Journals (Sweden)

Full Text Available The final most common pathway for the majority of coronary artery disease is occlusion of a coronary vessel. Under normal conditions, antithrombin III (AT III, protein C, and protein S as an active protein C cofactor, are natural anticoagulants (hemostatic control that balances procoagulant activity (thrombin antithrombin complex balance to prevent thrombosis. If the condition becomes unbalanced, natural anticoagulants and the procoagulants can lead to thrombosis. Thirty subjects with acute coronary syndrome (ACS were studied for the incidence of antithrombin III (AT III, protein C, and protein S deficiencies, and the result were compare to the control group. Among patients with ACS, the frequency of distribution of AT-III with activity < 75% were 23,3% (7 of 30, and only 6,7% ( 2 of 30 in control subject. No one of the 30 control subject have protein C activity deficient, in ACS with activity < 70% were 13,3% (4 of 30. Fifteen out of the 30 (50% control subjects had protein S activity deficiency, while protein S deficiency activity < 70% was found 73.3.% (22 out of 30. On linear regression, the deterministic coefficient of AT-III activity deficiency to the development ACS was 13,25 %, and the deterministic coefficient of protein C activity deficient to the development of ACS was 9,06 %. The cut-off point for AT-III without protein S deficiency expected to contribute to the development of vessel disease was 45%. On discriminant analysis, protein C activity deficiency posed a risk for ACS of 4,5 greater than non deficient subjects, and AT-III activity deficiency posed a risk for ACS of 3,5 times greater than non deficient subjects. On binary logistic regression, protein S activity acted only as a reinforcing factor of AT-III activity deficiency in the development of ACS. Protein C and AT III deficiency can trigger ACS, with determinant coefficients of 9,06% and 13,25% respectively. Low levels of protein C posed a greater risk of ACS than low levels of AT III. Protein S deficiency was a reinforcing factor on AT-III deficient to development of ACS. The cut-off point of AT-III without protein S deficiency expected to give single vessel disease was 45%, and 9,5% for the development of triple vessel disease. (Med J Indones 2002; 11: 87-92Keywords: acute coronary syndrome, Anti-thrombin III, Protein C, Protein S

Dasnan Ismail

2002-06-01

395

Topic Analysis Using a Finite Mixture Model.  

Science.gov (United States)

Presents a single framework for conducting topic analysis that performs both topic identification and text segmentation. Key characteristics of the framework are: representing a topic by means of a cluster of words closely related to the topic; and employing a stochastic model, called a finite mixture model, to represent a word distribution within…

Li, Hang; Yamanishi, Kenji

2003-01-01

396

Dictyocaulus viviparus: isolation and characterization of a recombinant antigen with potential for immunodiagnosis.  

Science.gov (United States)

Crude adult worm antigen of Dictyocaulus viviparus was examined for specific antigens by SDS-PAGE and immunoblotting using sera from cattle experimentally infected with D. viviparus, vaccinated with a normal or a reduced dosage of the commercial lungworm vaccine, and helminth-free cattle. A D. viviparus-specific region M(r) 18,000 was identified and isolated. A lambda ZAP II cDNA expression library consisting of 4.4 x 10(5) recombinant clones (88% of the total number of clones) was constructed from D. viviparus adult worm mRNA. Rabbit antiserum to the M(r) 18,000 antigen was used to screen the cDNA library and eight positive clones were picked and allocated to the same antigenic family by sibling analysis. All clones were subcloned into the plasmid pGEX-2T, and the clone with highest expression yields was expressed as a glutathione S-transferase fusion protein (DvGST3-14) or, after cleavage with thrombin, as pure recombinant parasite protein (Dv3-14). The native parasite antigen encoded by the clone was identified. The immunodiagnostic potential of the recombinant proteins was assessed by immunoblotting. PMID:1459787

Schnieder, T

1992-11-01

397

G-protein coupled and tyrosine kinase receptors: evidence that activation of the insulin-like growth factor I receptor is required for thrombin-induced mitogenesis of rat aortic smooth muscle cells.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

IGF I is an ubiquitous peptide that activates a membrane tyrosine kinase receptor and has autocrine/paracrine effects on vascular smooth muscle cells. Thrombin activates a G-protein coupled receptor and is also a mitogen for vascular smooth muscle cells. To assess the potential role of IGF I as a mediator of thrombin's effects, we characterized expression of IGF I and of its receptor on vascular smooth muscle cells exposed to thrombin. Thrombin dose-dependently decreased IGF I mRNA levels and...

Delafontaine, P.; Anwar, A.; Lou, H.; Ku, L.

1996-01-01

398

Recent topics in CP violation  

CERN Multimedia

Recent topics regarding CP violation in heavy meson systems are discussed. As an introduction, the status of the Unitarity Triangle fit and CP violation in B meson mixing are briefly reviewed. Two topics are covered in more detail: Penguin pollution in the "golden mode" B_d to J/psi K has gained importance due to the apparent smallness of new physics effects, together with the outstanding precision expected from present and future collider experiments. A very recent analysis is presented, which yields a stronger bound for the maximal influence of penguin contributions than previous analyses and shows the corresponding uncertainty to be reducible with coming data. Direct CP violation in hadronic charm decays received a lot of attention lately, due to a measurement by the LHCb collaboration yielding an unexpectedly large result. While this value is certainly not generically predicted in the Standard Model, it might be possible to accommodate it nevertheless. Therefore a method is discussed to use flavour symmet...

Jung, Martin

2012-01-01

399

Major research topics in combustion  

Energy Technology Data Exchange (ETDEWEB)

The Institute for Computer Applications in Science and Engineering (ICASE) and NASA Langley Research Center (LaRC) hosted a workshop on October 2--4, 1989 to discuss some combustion problems of technological interest to LaRC and to foster interaction with the academic community in these research areas. The topics chosen for this purpose were flame structure, flame holding/extinction, chemical kinetics, turbulence-kinetics interaction, transition to detonation, and reacting free shear layers. This document contains the papers and edited versions of general discussions on these topics. The lead paper set the stage for the meeting by discussing the status and issues of supersonic combustion relevant to the scramjet engine. Experts were then called upon to review the current knowledge in the aforementioned areas, to focus on how this knowledge can be extended and applied to high-speed combustion, and to suggest future directions of research in these areas.

Hussaini, M.Y.; Kumar, A.; Voigt, R.G. (eds.)

1992-01-01

400

Hot topics from the Tevatron  

Energy Technology Data Exchange (ETDEWEB)

The Tevatron Run-II began in March 2001. To date, both the CDF and D0 experiments have collected 1 fb{sup -1} of data each. The results obtained from this data set were summarized at this conference in 39 parallel session presentations covering a wide range of topics. The author summarizes the most important of those results here and comments on some of the prospects for the future.

Glenzinski, D.; /Fermilab

2008-01-01