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Sample records for thrombin topical recombinant

  1. Topical thrombin preparations and their use in cardiac surgery

    Brianne L Dunn

    2009-10-01

    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 

  2. Thrombin

    Di Cera, Enrico

    2008-01-01

    Thrombin is a Na+-activated, allosteric serine protease that plays opposing functional roles in blood coagulation. Binding of Na+ is the major driving force behind the procoagulant, prothrombotic and signaling functions of the enzyme, but is dispensable for cleavage of the anticoagulant protein C. The anticoagulant function of thrombin is under the allosteric control of the cofactor thrombomodulin. Much has been learned on the mechanism of Na+ binding and recognition of natural substrates by ...

  3. Recombinant thrombin: safety and immunogenicity in burn wound excision and grafting.

    Greenhalgh, David G; Gamelli, Richard L; Collins, Jay; Sood, Rajiv; Mozingo, David W; Gray, Todd E; Alexander, W Allan

    2009-01-01

    This study evaluated the safety, immunogenicity, and hemostatic effect of recombinant human Thrombin (rThrombin), in patients undergoing skin grafting for burns. This was a phase 2 multiple site, single-arm, open-label study in patients receiving partial- or full-thickness autologous grafts. rThrombin was applied using a spray applicator to newly excised wounds of 1 to 4% body surface area at 5 minutes intervals for up to 20 minutes, after point source bleeding was stopped. Adverse events, skin graft survival, and formation of anti-rThrombin antibodies were measured at baseline and Day 29. There were no deaths or study drug discontinuations. Adverse events occurred in 63 of 72 patients (88%), and were typical of sequelae of skin grafting. Hemostasis was achieved within 20 minutes after application of rThrombin in 65 of 71 patients (91.5%). Skin graft failure occurred in 4 patients (6%). At the day 29 evaluation, for those patients who returned, 88.9% had > or =90% graft survival. One patient (1 of 70, 1.4%) had specific, low titer antibodies to rThrombin at baseline, but no increase in titer posttreatment; a second patient (1 of 62, 1.6%), developed antibodies to rThrombin at day 29. None of the antibodies neutralized native human thrombin. In excised burn wounds, hemostasis at 20 minutes was achieved in 91.5% of patients and skin graft survival was excellent. There was a low rate of antibodies to rThrombin at baseline (1.4%) and a low rate of anti-rThrombin antibody formation at day 29 (1.6%). rThrombin was well tolerated when administered with a pump spray. PMID:19349898

  4. Thrombin-targeting recombinant hirudin as a new thrombus imaging ligand in dog thrombosis model

    Objective: To assess the ability of the direct thrombin (Th) inhibitor, recombinant hirudin (rH) as a new thrombus imaging ligand. Methods: 125I-rH was prepared by chloramine-T method, 99Tcm-rH by modified 2-imino-thiolane method. The affinity of rH to Th-fibrin complex was analyzed by the competitive radioassay in vitro, the kinetics of the rH-Th-fibrin complex formation was studied too. Biodistribution of 99Tcm-rH in mice was determined and thrombus imaging was performed in dog thrombosis model. Results: The rH could only bind with Th-fibrin complex, but not directly with fibrinogen and the binding was of fairly high specificity and avidity. The biodistribution study in mice demonstrated that rH was excreted from kidneys [(64.724 +- 5.042)% ID/organ within 15 min after injection] and there was low uptake in heart, brain, liver, spleen and lungs. In SPECT imaging, all thrombi were clearly visible, arterial thrombi were seen clearly within 45 min after injection (T/B=1.47) and faded away slowly, venous thrombi were also seen within 30 min after injection and quantitative imaging ratios of the thrombus to the contralateral vessel increased with time (T/B=1.53 in 60 min). Conclusions: All these results indicate that Th probably can be regarded as the target or marker in diagnosis of thrombus formation and rH can be used as a new ligand in thrombus imaging

  5. Nanostructured bioluminescent sensor for rapidly detecting thrombin.

    Chen, Longyan; Bao, Yige; Denstedt, John; Zhang, Jin

    2016-03-15

    Thrombin plays a key role in thrombosis and hemostasis. The abnormal level of thrombin in body fluids may lead to different diseases, such as rheumatoid arthritis, glomerulonephritis, etc. Detection of thrombin level in blood and/or urine is one of important methods for medical diagnosis. Here, a bioluminescent sensor is developed for non-invasively and rapidly detecting thrombin in urine. The sensor is assembled through conjugating gold nanoparticles (Au NPs) and a recombinant protein containing Renilla luciferase (pRluc) by a peptide, which is thrombin specific substrate. The luciferase-catalyzed bioluminescence can be quenched by peptide-conjugating Au NPs. In the presence of thrombin, the short peptide conjugating luciferase and Au NPs is digested and cut off, which results in the recovery of bioluminescence due to the release of luciferase from Au NPs. The bioluminescence intensity at 470 nm is observed, and increases with increasing concentration of thrombin. The bioluminescence intensity of this designed sensor is significantly recovered when the thrombin digestion time lasts for 10 min. In addition, a similar linear relationship between luminescence intensity and the concentration of thrombin is found in the range of 8 nM to 8 μM in both buffer and human urine spiked samples. The limit of detection is as low as 80 pM. It is anticipated that our nanosensor could be a promising tool for clinical diagnosis of thrombin in human urine. PMID:26397418

  6. Enhancement of incisional wound healing and neovascularization in normal rats by thrombin and synthetic thrombin receptor-activating peptides.

    Carney, D H; Mann, R.; Redin, W R; Pernia, S D; Berry, D; Heggers, J P; Hayward, P G; Robson, M. C.; Christie, J.; Annable, C

    1992-01-01

    To better define thrombin-receptor interactions, we synthesized human thrombin peptides and identified binding-domain peptides that bind thrombin receptors and activate mitogenic signals (Glenn, K.C., G.H. Frost, J.S. Bergmann, and D.H. Carney. 1988. Pept. Res. 1:65-73). Treatment of full dermal dorsal incisions with a single topical application of thrombin receptor-activating peptide (TRAP-508) or human alpha-thrombin in saline enhances 7-d incisional breaking strength in normal rats up to 8...

  7. The use of thrombin in the radiology department.

    Ward, E

    2009-03-01

    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.

  8. "Mirror image" antagonists of thrombin-induced platelet activation based on thrombin receptor structure.

    Hung, D T; Vu, T K; Wheaton, V I; Charo, I F; Nelken, N A; Esmon, N.; ESMON, C.T.; Coughlin, S.R.

    1992-01-01

    Platelet activation by thrombin plays a critical role in hemostasis and thrombosis. Based on structure-activity studies of a cloned platelet thrombin receptor, we designed two "mirror image" antagonists of thrombin and thrombin receptor function. First, "uncleavable" peptides mimicking the receptor domain postulated to interact with thrombin were found to be potent thrombin inhibitors. Second, proteolytically inactive mutant thrombins designed to bind but not cleave the thrombin receptor were...

  9. Thrombin Inhibitors from Different Animals

    A. M. Tanaka-Azevedo; Morais-Zani, K.; Torquato, R. J. S.; A. S. Tanaka

    2010-01-01

    Venous and arterial thromboembolic diseases are still the most frequent causes of death and disability in high-income countries. Clinical anticoagulants are inhibitors of enzymes involved in the coagulation pathway, such as thrombin and factor Xa. Thrombin is a key enzyme of blood coagulation system, activating the platelets, converting the fibrinogen to the fibrin net, and amplifying its self-generation by the activation of factors V, VIII, and XI. Thrombin has long been a target for the dev...

  10. Multiple inhibitory kinetics reveal an allosteric interplay among thrombin functional sites.

    Zavyalova, Elena; Kopylov, Alexey

    2015-01-01

    Thrombin is a key blood clotting enzyme; therefore, developing of its inhibitors has become a mainstream in antithrombotic pharmacology. As a result, a wide variety of proteins, peptides, peptidomimetics, DNA, RNA, and carbohydrates were reported to be effective inhibitors of thrombin activities. The majority of described inhibitors were characterized kinetically with amidolytic assay only; though some of them inhibit fibrinogen binding rather than amidolytic activity, e.g. hirugen and nucleic acid aptamers. Per contra, studying the inhibition kinetics of fibrinogen hydrolysis might reveal essential peculiarities of mechanism of action of thrombin inhibitors. In this paper the effect of thrombin inhibitors on fibrinogen hydrolysis has been investigated using improved turbidimetric assay. This technique is highly productive versus fibrinopeptide determination allowing elucidation of inhibition type and apparent constant for different types of thrombin inhibitors. The protein (recombinant hirudin, antithrombin III), peptide (bivalirudin, hirugen), and peptidomimetic (argatroban, PPACK) inhibitors were characterized in terms of inhibition types for the first time. Unexpectedly, for others: heparin, RNA aptamer Toggle-25t, partial inhibition has been shown indicating allosteric interplay between exosites. Improved turbidimetric assay is also applicable for studying the fibrin association inhibitors. Hence, GPRP-peptide was characterized kinetically for the first time. The kinetic study revealed a repertoire of different inhibition types and also close allosteric interplay within the thrombin. The results are undoubtedly important for understanding the enzyme activity regulation, as well as for the rational development of new antithrombotic substances. PMID:25467079

  11. Bronchoconstrictor effect of thrombin and thrombin receptor activating peptide in guinea-pigs in vivo

    Cicala, Carla; Bucci, Mariarosaria; De Dominicis, Gianfranco; Harriot, Pat; Sorrentino, Ludovico; Cirino, Giuseppe

    1999-01-01

    Several thrombin cellular effects are dependent upon stimulation of proteinase activated receptor-1 (PAR-1) localized over the cellular surface. Following activation by thrombin, a new N-terminus peptide is unmasked on PAR-1 receptor, which functions as a tethered ligand for the receptor itself. Synthetic peptides called thrombin receptor activating peptides (TRAPs), corresponding to the N-terminus residue unmasked, reproduce several thrombin cellular effects, but are devoid of catalytic acti...

  12. Investigation of the selectivity of thrombin-binding aptamers for thrombin titration in murine plasma.

    Trapaidze, Ana; Hérault, Jean-Pascal; Herbert, Jean-Marc; Bancaud, Aurélien; Gué, Anne-Marie

    2016-04-15

    Detection of thrombin in plasma raises timely challenges to enable therapeutic management of thrombosis in patients under vital threat. Thrombin binding aptamers represent promising candidates as sensing elements for the development of real-time thrombin biosensors; however implementation of such biosensor requires the clear understanding of thrombin-aptamer interaction properties in real-like environment. In this study, we used Surface Plasmon Resonance technique to answer the questions of specificity and sensitivity of thrombin detection by the thrombin-binding aptamers HD1, NU172 and HD22. We systematically characterized their properties in the presence of thrombin, as well as interfering molecular species such as the thrombin precursor prothrombin, thrombin in complex with some of its natural inhibitors, nonspecific serum proteins, and diluted plasma. Kinetic experiments show the multiple binding modes of HD1 and NU172, which both interact with multiple sites of thrombin with low nanomolar affinities and show little specificity of interaction for prothrombin vs. thrombin. HD22, on the other hand, binds specifically to thrombin exosite II and has no affinity to prothrombin at all. While thrombin in complex with some of its inhibitors could not be recognized by any aptamer, the binding of HD1 and NU172 properties is compromised by thrombin inhibitors alone, as well as with serum albumin. Finally, the complex nature of plasma was overwhelming for HD1, but we define conditions for the thrombin detection at 10nM range in 100-fold diluted plasma by HD22. Consequently HD22 showed key advantage over HD1 and NU172, and appears as the only alternative to design an aptasensor. PMID:26594887

  13. Aptamer Based Microsphere Biosensor for Thrombin Detection

    Xudong Fan

    2006-08-01

    Full Text Available We have developed an optical microsphere resonator biosensor using aptamer asreceptor for the measurement of the important biomolecule thrombin. The sphere surface ismodified with anti-thrombin aptamer, which has excellent binding affinity and selectivityfor thrombin. Binding of the thrombin at the sphere surface is monitored by the spectralposition of the microsphere’s whispering gallery mode resonances. A detection limit on theorder of 1 NIH Unit/mL is demonstrated. Control experiments with non-aptameroligonucleotide and BSA are also carried out to confirm the specific binding betweenaptamer and thrombin. We expect that this demonstration will lead to the development ofhighly sensitive biomarker sensors based on aptamer with lower cost and higher throughputthan current technology.

  14. Nanocomplexation of thrombin with cationic amylose derivative for improved stability and hemostatic efficacy

    Zhuang B

    2015-01-01

    Full Text Available Baoxiong Zhuang,1,* Zhihua Li,1,* Jiadong Pang,2,* Wenbin Li,1 Pinbo Huang,1 Jie Wang,1 Yu Zhou,1 Qing Lin,1 Quanbo Zhou,1 Xiao Ye,1 Huilin Ye,1 Yimin Liu,1 Li-Ming Zhang,2 Rufu Chen1 1Department of Hepato-Pancreato-Billiary Surgery, Department of Medical Oncology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, People’s Republic of China; 2DSAPM Lab and PCFM Lab, Institute of Polymer Science, Department of Polymer and Materials Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, People’s Republic of China *Authors share co-first authorship Abstract: As a topical hemostatic agent, thrombin has wide application for many surgical treatments. However, native thrombin always suffers from its physical and chemical instabilities. In this work, a nanocomplexation strategy was developed for modifying the stability and hemostatic efficacy of thrombin, in which a water-soluble cationic amylose derivative containing poly(l-lysine dendrons was prepared by a click reaction and then used to complex thrombin in an aqueous system. For resultant thrombin nanocomplexes, their morphology and particle size distribution were investigated. Their stabilities were studied in terms of activity retention percentages under different storage time, pH values, and illumination time. In addition, their ability to achieve in vitro fibrinogen and blood coagulation were evaluated. Via a rat hepatic hemorrhage model and a rat iliac artery hemorrhage model, these thrombin nanocomplexes were confirmed to have good tissue biocompatibility and in vivo hemostatic effectiveness. Keywords: thrombin, nanoparticles, amylose derivative, complexation, stability, hemostatic activity

  15. Skin regeneration in deep second-degree scald injuries either by infusion pumping or topical application of recombinant human erythropoietin gel

    Giri, Priya; Ebert, Sabine; Braumann, Ulf-Dietrich; Kremer, Mathias; Giri, Shibashish; Machens, Hans-Gnther; Bader, Augustinus

    2015-01-01

    Large doses of recombinant growth factors formulated in solution form directly injected into the body is usual clinical practice in treating second-degree scald injuries, with promising results, but this approach creates side effects; furthermore, it may not allow appropriate levels of the factor to be sensed by the target injured tissue/organ in the specific time frame, owing to complications arising from regeneration. In this research, two delivery methods (infusion pumping and local topical application) were applied to deliver recombinant human erythropoietin (rHuEPO) for skin regeneration. First, rHuEPO was given in deep second-degree scald injury sites in mice by infusion pump. Vascularization was remarkably higher in the rHuEPO pumping group than in controls. Second, local topical application of rHuEPO gel was given in deep second-degree scald injury sites in rats. Histological analysis showed that epithelialization rate was significantly higher in the rHuEPO gel-treated group than in controls. Immunohistochemical studies showed that the rHuEPO gel-treated group showed remarkably higher expression of skin regeneration makers than the control group. An accurate method for visualization and quantification of blood vessel networks in target areas has still not been developed up to this point, because of technical difficulties in detecting such thin blood vessels. A method which utilizes a series of steps to enhance the image, removes noise from image background, and tracks the vessels edges for vessel segmentation and quantification has been used in this study. Using image analysis methods, we were able to detect the microvascular networks of newly formed blood vessels (less than 500 ?m thickness), which participate in the healing process, providing not only nutrition and oxygen to grow tissues but also necessary growth factors to grow tissue cells for complete skin regeneration. The rHuEPO-treated group showed higher expression of stem cell markers (CD 31, CD 90, CD 71, and nestin), which actively contribute to in-wound-healing processes for new hair follicle generation as well as skin regeneration. Collectively, both rHuEPO group pumping into the systemic circulation system, and injection into the local injury area, prompted mice and rats to form new blood vessel networks in scald injury sites, which significantly participate in the scald healing process. These results may lead to the development of novel treatments for scald wounds. PMID:26005333

  16. The unresolved safety concerns of bovine thrombin

    Javidroozi Mazyar; Shander Aryeh

    2008-01-01

    Abstract A recent review has suggested that bovine thrombin is not associated with an increased risk of bleeding in surgical populations. In spite of extremely limited evidence available, many valuable resources (e.g. safety surveillance and post-marketing programs, case reports) were excluded in reaching this conclusion. While waiting for the adequately powered, controlled clinical trials to address the effects of bovine thrombin on bleeding and thrombotic events, the potential risk cannot b...

  17. Acetazolamide Attenuates Thrombin-Induced Hydrocephalus.

    Gao, Feng; Zheng, Mingzhe; Hua, Ya; Keep, Richard F; Xi, Guohua

    2016-01-01

    Our previous studies demonstrated that thrombin is an important factor in brain injury after intracerebral and intraventricular hemorrhage. This study examined the effect of acetazolamide, a carbonic anhydrase inhibitor, on thrombin-induced hydrocephalus. There were two parts in this study. First, rats had an injection of either 50 μl saline or 3 U thrombin into the right lateral ventricle. Second, rats had an injection of 3 U thrombin into the right lateral ventricle and were treated with either vehicle or acetazolamide (30 mg/kg, intraperitoneally (IP)) at 1 h after thrombin infusion. Lateral ventricle volumes were measured in magnetic resonance imaging T2 images and the brains were used for histology analysis at 24 h later. Intraventricular injection of thrombin induced significantly larger ventricle volume (27.8 ± 3.7 vs 8.5 ± 1.3 mm(3), n = 6, p hydrocephalus (16.1 ± 4.2 mm(3) vs 29.5 ± 5.3 mm(3), n = 6, p hydrocephalus in rats. PMID:26463977

  18. Skin regeneration in deep second-degree scald injuries either by infusion pumping or topical application of recombinant human erythropoietin gel

    Giri P

    2015-05-01

    Full Text Available Priya Giri,1 Sabine Ebert,1 Ulf-Dietrich Braumann,2 Mathias Kremer,3 Shibashish Giri,1 Hans-Günther Machens,4 Augustinus Bader1 1Department of Cell Techniques and Applied Stem Cell Biology, Center for Biotechnology and Biomedicine (BBZ, Faculty of Medicine, University of Leipzig, Leipzig, Germany; 2Interdisciplinary Center for Bioinformatics (IZBI, University of Leipzig, Leipzig, Germany; 3Department of Plastic and Hand Surgery, University of Lübeck, Lübeck, Germany; 4Department of Plastic and Hand Surgery, Technical University of Munich, Munich, Germany Abstract: Large doses of recombinant growth factors formulated in solution form directly injected into the body is usual clinical practice in treating second-degree scald injuries, with promising results, but this approach creates side effects; furthermore, it may not allow appropriate levels of the factor to be sensed by the target injured tissue/organ in the specific time frame, owing to complications arising from regeneration. In this research, two delivery methods (infusion pumping and local topical application were applied to deliver recombinant human erythropoietin (rHuEPO for skin regeneration. First, rHuEPO was given in deep second-degree scald injury sites in mice by infusion pump. Vascularization was remarkably higher in the rHuEPO pumping group than in controls. Second, local topical application of rHuEPO gel was given in deep second-degree scald injury sites in rats. Histological analysis showed that epithelialization rate was significantly higher in the rHuEPO gel-treated group than in controls. Immunohistochemical studies showed that the rHuEPO gel-treated group showed remarkably higher expression of skin regeneration makers than the control group. An accurate method for visualization and quantification of blood vessel networks in target areas has still not been developed up to this point, because of technical difficulties in detecting such thin blood vessels. A method which utilizes a series of steps to enhance the image, removes noise from image background, and tracks the vessels edges for vessel segmentation and quantification has been used in this study. Using image analysis methods, we were able to detect the microvascular networks of newly formed blood vessels (less than 500 µm thickness, which participate in the healing process, providing not only nutrition and oxygen to grow tissues but also necessary growth factors to grow tissue cells for complete skin regeneration. The rHuEPO-treated group showed higher expression of stem cell markers (CD 31, CD 90, CD 71, and nestin, which actively contribute to in-wound-healing processes for new hair follicle generation as well as skin regeneration. Collectively, both rHuEPO group pumping into the systemic circulation system, and injection into the local injury area, prompted mice and rats to form new blood vessel networks in scald injury sites, which significantly participate in the scald healing process. These results may lead to the development of novel treatments for scald wounds. Keywords: re-epithelialization, scald wound, skin regeneration, neovascularization, vascularization, segmentation

  19. Thrombin regulates the function of human blood dendritic cells

    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

  20. The Transition of Prothrombin to Thrombin

    Krishnaswamy, Sriram

    2013-01-01

    The proteolytic conversion of prothrombin to thrombin catalysed by prothrombinase is one of the more extensively studied reactions of blood coagulation. Sophisticated biophysical and biochemical insights into the players of this reaction were developed in the early days of the field. Yet, many basic enzymological questions remained unanswered. I summarise new developments that uncover mechanisms by which high substrate specificity is achieved, and the impact of these strategies on enzymic fun...

  1. Investigation of a thrombin-complexing protein associated with platelets

    A fraction of the 125I-thrombin that binds to human platelets is taken into a sodium dodecyl sulfate-resistant 77k Da complex with a platelet factor. This platelet factor is in several respects similar to protease nexin I (PNI), a fibroblasts thrombin inhibitor. The complexes are of the right size, bind to agarose that has been derivatized with either anti-PNI antibody or heparin, do not form when the thrombin active site has been blocked with diisopropylphosphofluoridate, and do not appear on platelets when heparin is present. The interaction with the platelet surface may modulate the conformation and function of this platelet form of protease nexin I (PNIp) because: (i) an antibody against protease nexi I inhibited released PNIp, but not platelet-bound PNIp from complexing 125I-thrombin, and (ii) whereas PNIp extracted from platelets bound both thrombin and urokinase, platelet-bound PNIp bound only thrombin. In experiments employing several different platelet isolation methods, PNIp accounted for a large fraction of the rapid high affinity binding of 125I-thrombin to platelets. However, platelets isolated and maintained in the presence of metabolic inhibitors failed to take added thrombin into 125I-thrombine-PNIp complexes

  2. Cartilage oligomeric matrix protein is a natural inhibitor of thrombin.

    Liang, Ying; Fu, Yi; Qi, Ruomei; Wang, Meili; Yang, Nan; He, Li; Yu, Fang; Zhang, Jian; Yun, Cai-Hong; Wang, Xian; Liu, Junling; Kong, Wei

    2015-08-13

    Thrombin is an effector enzyme for hemostasis and thrombosis; however, endogenous regulators of thrombin remain elusive. Cartilage oligomeric matrix protein (COMP), a matricellular protein also known as thrombospondin-5, is essential for maintaining vascular homeostasis. Here, we asked whether COMP is involved in the process of blood coagulation. COMP deficiency shortened tail-bleeding and clotting time and accelerated ferric-chloride-induced thrombosis in mice. The absence of COMP had no effect on platelet count. In contrast, COMP specifically inhibited thrombin-induced platelet aggregation, activation, and retraction and the thrombin-mediated cleavage of fibrinogen. Furthermore, surface plasmon resonance analysis revealed direct thrombin-COMP binding (KD = 1.38 ± 0.24 μM). In particular, blockage of thrombin exosites with compounds specific for exosite I (hirudin and HD1 aptamer) or exosite II (heparin and HD22 aptamer) impaired the COMP-thrombin interaction, indicating a 2-site binding mechanism. Additionally, epidermal growth factor-like repeats (amino acids 84-261) were identified as a COMP binding site for thrombin. Moreover, COMP was expressed in and secreted by platelets. Using bone marrow transplantation and platelet transfusion to create chimeric mice, platelet-derived but not vessel-wall-derived COMP was demonstrated to inhibit coagulation. Taken together, COMP is an endogenous thrombin inhibitor and negative regulator of hemostasis and thrombosis. PMID:26045608

  3. Thrombin functions as an inflammatory mediator through activation of its receptor

    1996-01-01

    A rat model of inflammation was used to investigate the biological effects of thrombin. The thrombin-specific inhibitor Hirulog markedly attentuated the carrageenin-induced edema of the paw of the rat. Injection of thrombin into the paw also produced edema. The effect of thrombin was due to activation of its receptor; a thrombin receptor activating peptide (TRAP) reproduced the effects of thrombin in causing edema. TRAP also increased vascular permeability as demonstrated by extravasation of ...

  4. XIMELAGATRAN: A NEW DIRECT THROMBIN INHIBITOR

    Mehta Hiren R

    2011-04-01

    Full Text Available Venous thromboembolism is a serious illness that affects patient morbidity and mortality and presents a significant management challenge to healthcare providers world-wide. Despite major achievements in the significant reduction of thromboembolic complications, the most common therapies currently used for prevention and treatment of venous thromboembolism – heparins and vitamin K antagonists such as warfarin – have several limitations. Warfarin sodium is an effective oral anticoagulant drug. However, warfarin has a narrow therapeutic window with significant risks of hemorrhage at therapeutic concentrations. Dosing is difficult and requires frequent monitoring. New oral anticoagulant agents are required to improve current anticoagulant therapy. Furthermore, while warfarin is effective in venous disease, it does not provide more than 60% risk reduction compared with placebo in venous thrombosis prophylaxis and considerably lower risk reduction in terms of arterial thrombosis. Unlike warfarin and heparin, these direct thrombin inhibitors are able to inhibit fibrin-bound thrombin and so produce more effective inhibition of coagulation. Importantly, some members of this class of drugs have been developed for oral administration. Ximelagatran is an oral pro-drug of melagatran, a synthetic small peptidomimetic with direct thrombin inhibitory actions and anticoagulant activity. As an oral agent, ximelagatran has a number of desirable properties including a rapid onset of action, fixed dosing, stable absorption, apparent low potential for medication interactions, and no requirement for monitoring of drug levels or dose adjustment. It has a short plasma elimination half-life of about 4 hours in cases of unexpected hemorrhage or need for reversal.

  5. SLOW THROMBIN IS ZYMOGEN-LIKE

    Huntington, James A.

    2009-01-01

    Blood coagulation is the result of a cascade of zymogen activation events, however, its initiation is allosteric. Factor VIIa circulates in a zymogen-like state and is allosterically activated by binding to tissue factor. Thrombin, the final protease generated in the blood coagulation cascade, has also been shown to exist in a low activity state in the absence of cofactors, and the structural features of this ‘slow’ form has been studied for many years. In this manuscript I will review the ge...

  6. Acidosis, magnesium and acetylsalicylic acid: Effects on thrombin

    Borisevich, Nikolaj; Loznikova, Svetlana; Sukhodola, Aleksandr; Halets, Inessa; Bryszewska, Maria; Shcharbin, Dzmitry

    2013-03-01

    Thrombin, an enzyme from the hydrolase family, is the main component of the blood coagulation system. In ischemic stroke it acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin forming blood clots in the brain. It has been found to phosphoresce at room temperature in the millisecond and microsecond ranges. The phosphorescence of thrombin was studied under physiological conditions, in acidosis (decrease of pH from 8.0 to 5.0) and on the addition of salts (magnesium sulfate and sodium chloride) and of acetylsalicylic acid, and its connection with thrombin function is discussed. Acidosis significantly increased the internal dynamics of thrombin. We propose that lactate-acidosis plays a protective role in stroke, preventing the formation of clots. The addition of NaCl and MgSO4 in different concentrations increased the internal dynamics of thrombin. Also, the addition of MgSO4 decreased thrombin-induced platelet aggregation. However, magnesium sulfate and acetylsalicylic acid in the therapeutic concentrations used for treatment of ischemic stroke had no effect on thrombin internal dynamics. The data obtained will help to elucidate the conformational stability of thrombin under conditions modulating lactate-acidosis and in the presence of magnesium sulfate.

  7. A thrombin receptor in resident rat peritoneal macrophages

    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

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

    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).

  9. APTAMER-BASED SERRS SENSOR FOR THROMBIN DETECTION

    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

    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.

  10. The interaction of thrombin with platelet protease nexin

    Thrombin interacts with a platelet protein which is immunologically related to fibroblast protease nexin and has been termed platelet protease nexin I (PNI). Conflicting hypotheses about the relationship of the thrombin-PNI complex formation to platelet activation have been proposed. The studies presented here demonstrate that the platelet-associated and supernatant complexes with added 125I-thrombin are formed only under conditions which produce platelet activation in normal and chymotrypsin-modified platelets. The platelet-associated complex is formed prior to the appearance of complexes in supernatants. Appearance of the supernatant complex coincides with the appearance of thrombospondin in the reaction supernatants. Excess native thrombin, dansylarginine N-(3-ethyl-1,5-pentanediyl) amide or hirudin can prevent radiolabeled platelet-associated complex formation if added before 125I-thrombin. DAPA or hirudin can prevent or dissociate complex formation if added up to one minute after thrombin but not at later time points. The surface associated complex is accessible to trypsin although a portion remains with the cytoskeletal proteins when thrombin-activated platelets are solubilized with Triton X 100. The surface-associated complex formation parallels many aspects of the specific measurable thrombin binding, yet it does not appear to involve other identified surface glycoprotein thrombin receptors or substrates. Although the time course of appearance of the complexes in supernatants is consistent with other data which suggest that PNI may be released from platelet granules during platelet activation, other explanations for the appearance of PNI on the platelet surface and in supernatants during platelet activation are possible

  11. Thrombin binding to human brain and spinal cord

    Thrombin, a serine protease that regulates hemostasis, has been shown to stimulate the formation of cGMP in murine neuroblastoma cells. The nervous system in vivo thus may be postulated to respond to this blood-borne factor after it breaches the blood-brain barrier, as in trauma. Human alpha-thrombin was radiolabeled with 125I and shown to bind rapidly, reversibly, and with high affinity to human brain and spinal cord. These findings indicate the presence of specific thrombin-binding sites in nervous tissue and may have important clinical implications

  12. Hydrocephalus after intraventricular hemorrhage: the role of thrombin

    Feng GAO; Liu, Fuyi; Chen, Zhi; Hua, Ya; Keep, Richard. F.; Xi, Guohua

    2013-01-01

    Previous studies demonstrated that thrombin is an important factor in brain injury after intracerebral hemorrhage. This study investigated the effect of thrombin on hydrocephalus development in a rat intraventricular hemorrhage (IVH) model. There were three parts in this study. First, male Sprague–Dawley rats had an injection of 200 μL saline, autologous blood or heparinized blood, into the right lateral ventricle. Second, rats had an injection of 50 μL saline or 3U thrombin into the right la...

  13. Increased thrombin generation in women with polycystic ovary syndrome

    Glintborg, Dorte; Sidelmann, Johannes Jakobsen; Lambaa Altinok, Magda; Mumm, Hanne; Andersen, Marianne

    2015-01-01

    randomized to 12 months treatment with metformin, metformin + OC or OC alone. C-reactive protein (CRP), fibrinogen, total cholesterol, trunk fat mass, body mass index, estradiol, testosterone, sex hormone binding globulin (SHBG) as well as TG measures, i.e. the lag time for formation of thrombin, the...... endogenous thrombin potential (ETP), peak thrombin concentration (peak) and time to peak were determined at baseline and after 12 months of treatment. Results. CRP and total testosterone were significantly higher and SHBG significantly lower in PCOS women than in controls (P=0.012, P<0.001 and P=0...

  14. Crystallization and preliminary X-ray analysis of the complex of human ?-thrombin with a modified thrombin-binding aptamer

    The complex between human ?-thrombin and a modified thrombin-binding aptamer has been crystallized. Diffraction data were collected to 2.15 resolution, the structure was solved by molecular replacement and refinement of the model is in progress. The thrombin-binding aptamer (TBA) is a consensus DNA 15-mer that binds specifically to human ?-thrombin at nanomolar concentrations and inhibits its procoagulant functions. Recently, a modified TBA (mTBA) containing a 5?5? inversion-of-polarity site has been shown to be more stable and to possess a higher thrombin affinity than its unmodified counterpart. The structure of the thrombinTBA complex has previously been determined at low resolution, but did not provide a detailed picture of the aptamer conformation or of the proteinDNA assembly, while that of the complex with mTBA is unknown. Crystallographic analysis of the thrombinmTBA complex has been attempted. The crystals diffracted to 2.15 resolution and belonged to space group I222

  15. Concentration-Dependent Dual Role of Thrombin in Protection of Cultured Rat Cortical Neurons.

    Garca, Paul S; Ciavatta, Vincent T; Fidler, Jonathan A; Woodbury, Anna; Levy, Jerrold H; Tyor, William R

    2015-11-01

    Thrombin's role in the nervous system is not well understood. Under conditions of blood-brain barrier compromise (e.g., neurosurgery or stroke), thrombin can result in neuroapoptosis and the formation of glial scars. Despite this, preconditioning with thrombin has been found to be neuroprotective in models of cerebral ischemia and intracerebral hemorrhage. We investigated the effects of physiologically relevant concentrations of thrombin on cortical neurons using two culture-based assays. We examined thrombin's effect on neurites by quantitative analysis of fluorescently labeled neurons. To characterize thrombin's effects on neuron survival, we spectrophotometrically measured changes in enzymatic activity. Using receptor agonists and thrombin inhibitors, we separately examined the role of thrombin and its receptor in neuroprotection. We found that low concentrations of thrombin (1nM) enhances neurite growth and branching, neuron viability, and protects against excitotoxic damage. In contrast, higher concentrations of thrombin (100nM) are potentially detrimental to neuronal health as evidenced by inhibition of neurite growth. Lower concentrations of thrombin resulted in equivalent neuroprotection as the antifibrinolytic, aprotinin, and the direct thrombin inhibitor, argatroban. Interestingly, exogenous application of the species-specific thrombin inhibitor, antithrombin III, was detrimental to neuronal health; suggesting that some endogenous thrombin is necessary for optimal neuron health in our culture system. Activation of the thrombin receptor, protease-activated receptor-1 (PAR-1), via micromolar concentrations of the thrombin receptor agonist peptide, TRAP, did not adversely affect neuronal viability. An optimal concentration of thrombin exists to enhance neuronal health. Neurotoxic effects of thrombin do not involve activation of PAR receptors and thus separate pharmacologic manipulation of thrombin's receptor in the setting of direct thrombin inhibitors could be a potential neuroprotective strategy. PMID:26342829

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

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

    1994-01-01

    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...

  17. Hydrocephalus after intraventricular hemorrhage: the role of thrombin.

    Gao, Feng; Liu, Fuyi; Chen, Zhi; Hua, Ya; Keep, Richard F; Xi, Guohua

    2014-03-01

    Previous studies demonstrated that thrombin is an important factor in brain injury after intracerebral hemorrhage. This study investigated the effect of thrombin on hydrocephalus development in a rat intraventricular hemorrhage (IVH) model. There were three parts in this study. First, male Sprague-Dawley rats had an injection of 200 μL saline, autologous blood or heparinized blood, into the right lateral ventricle. Second, rats had an injection of 50 μL saline or 3U thrombin into the right lateral ventricle. Third, rats had an injection of thrombin (3U) with a protease-activated receptor-1 (PAR-1) antagonist, SCH79797 (0.15 nmol), or vehicle into the right lateral ventricle. Lateral ventricle volumes were measured by magnetic resonance imaging and the brains were used for immunohistochemistry and western blot analyses. Intraventricular injection of autologous blood induced hydrocephalus from day 1 to 28. Heparinized blood injection resulted in less hydrocephalus at all time points compared with blood injection alone (Phydrocephalus, ventricular wall damage, and periventricular blood-brain barrier disruption. Thrombin-induced hydrocephalus was reduced by co-injection of the PAR-1 antagonist SCH79797 (Phydrocephalus development after IVH and thrombin-induced hydrocephalus is through PAR-1. PMID:24326390

  18. Activation of human factor V by factor Xa and thrombin

    The activation of human factor V by factor Xa and thrombin was studied by functional assessment of cofactor activity and sodium dodecyl sulfate-polycarylamide gel electrophoresis followed by either autoradiography of 125I-labeled factor V activation products or Western blot analyses of unlabeled factor V activation products. Cofactor activity was measured by the ability of the factor V/Va peptides to support the activation of prothrombin. The factor Xa catalyzed cleavage of factor V was observed to be time, phospholipid, and calcium ion dependent, yielding a cofactor with activity equal to that of thrombin-activated factor V (factor Va). The cleavage pattern differed markedly from the one observed in the bovine system. The factor Xa activated factor V subunits expressing cofactor activity were isolated and found to consist of peptides of Mr 220,000 and 105,000. Although thrombin cleaved the Mr 220,000 peptide to yield peptides previously shown to be products of thrombin activation, cofactor activity did not increase. N-Terminal sequence analysis confirmed that both factor Xa and thrombin cleave factor V at the same bond to generate the Mr 220,000 peptide. The factor Xa dependent functional assessment of 125I-labeled factor V coupled with densitometric analyses of the cleavage products indicated that the cofactor activity of factor Xa activated factor V closely paralleled the appearance of the Mr 220,000 peptide. The data indicate that factor Xa is as efficient an enzyme toward factor V as thrombin

  19. Rapid Detection of Thrombin and Other Protease Activity Directly in Whole Blood

    Yu, Johnson Chung Sing

    Thrombin is a serine protease that plays a key role in the clotting cascade to promote hemostasis following injury to the endothelium. From a clinical diagnostic perspective, in-vivo thrombin activity is linked to various blood clotting disorders, as well as cardiovascular disease (DVT, arteriosclerosis, etc). Thus, the ability to rapidly measure protease activity directly in whole blood will provide important new diagnostics, and clinical researchers with a powerful tool to further elucidate the relationship between circulating protease levels and disease. The ultimate goal is to design novel point of care (POC) diagnostic devices that are capable of monitoring protease activities directly in whole blood and biological sample. A charge-changing substrate specific to the thrombin enzyme was engineered and its functionality was confirmed by a series of experiments. This led to the preliminary design, construction, and testing of two device platforms deemed fully functional for the electrophoretic separation and focusing of charged peptide fragments. The concept of using the existing charge-changing substrate platform for bacterial protease detection was also investigated. Certain strains of E coli are associated with severe symptoms such as abdominal cramps, bloody diarrhea, and vomiting. The OmpT protease is expressed on the outer membrane of E coli and plays a role in the cleavage of antimicrobial peptides, the degradation of recombinant heterologous proteins, and the activation of plasminogen in the host. Thus, a synthetic peptide substrate specific to the OmpT protease was designed and modeled for the purpose of detecting E coli in biological sample.

  20. [Expectation to and problems of thrombin inhibitor].

    Uchiyama, Shinichiro

    2011-11-01

    Dabigatran is a direct thrombin inhibitor, does not require blood coagulation monitoring and limitation of vitamin K intake as well as very few drug interactions, and thus expected to be an oral anticoagulant alternative to warfarin. Randomized Evaluation of Long Term Anticoagulant Therapy (RE-LY) was conducted to determine non-inferiority of dabigatran against warfarin as an international multicenter-cooperative randomized trial in patients with non-valvular atrial fibrillation (NVAF). The results showed not only non-inferiority of dabigatran but also superiority of high-dose dabigatran in efficacy and of low-dose dabigatran in safety. In a sub-analysis of RE-LY in NVAF patients with history of stroke or TIA, who are at high risk of intracranial hemorrhage with anticoagulants, hemorrhagic stroke was much less frequent in patients on either dose of dabigatran than in those on warfarin. In a sub-analysis of RE-LY in Japanese patients with NVAF, the results showed a consistency of the efficacy and safety profiles of dabigatran with the results of the global RE-LY trial. Use of dabigatran should be contraindicated in NVAF patients with renal insufficiency because some cases with fatal bleeding have been reported in a post marketing survey. PMID:22277458

  1. Biochemical characterization of bovine plasma thrombin-activatable fibrinolysis inhibitor (TAFI

    Kristensen Torsten

    2009-05-01

    Full Text Available Abstract Background TAFI is a plasma protein assumed to be an important link between coagulation and fibrinolysis. The three-dimensional crystal structures of authentic mature bovine TAFI (TAFIa in complex with tick carboxypeptidase inhibitor, authentic full lenght bovine plasma thrombin-activatable fibrinolysis inhibitor (TAFI, and recombinant human TAFI have recently been solved. In light of these recent advances, we have characterized authentic bovine TAFI biochemically and compared it to human TAFI. Results The four N-linked glycosylation sequons within the activation peptide were all occupied in bovine TAFI, similar to human TAFI, while the sequon located within the enzyme moiety of the bovine protein was non-glycosylated. The enzymatic stability and the kinetic constants of TAFIa differed somewhat between the two proteins, as did the isoelectric point of TAFI, but not TAFIa. Equivalent to human TAFI, bovine TAFI was a substrate for transglutaminases and could be proteolytically cleaved by trypsin or thrombin/solulin complex, although small differences in the fragmentation patterns were observed. Furthermore, bovine TAFI exhibited intrinsic activity and TAFIa attenuated tPA-mediated fibrinolysis similar to the human protein. Conclusion The findings presented here suggest that the properties of these two orthologous proteins are similar and that conclusions reached using the bovine TAFI may be extrapolated to the human protein.

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

    Demopoulos Constantinos A; Tsekes George; Lioni Athina; Tsogas Nickolaos; Chini Maria; Tsoupras Alexandros B; Lazanas Marios C

    2011-01-01

    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. I...

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    ... condition may improve as soon as 4 weeks after you begin to use topical bexarotene, or it may ... notice any improvement. Continue to use topical bexarotene after you notice improvement; your condition may continue to improve. ...

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

    Demopoulos Constantinos A

    2011-07-01

    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.

  5. Aptamer RA36 inhibits of human, rabbit, and rat plasma coagulation activated with thrombin or snake venom coagulases.

    Savchik, E Yu; Kalinina, T B; Drozd, N N; Makarov, V A; Zav'yalova, E G; Lapsheva, E N; Mudrik, N N; Babij, A V; Pavlova, G V; Golovin, A V; Kopylov, A M

    2013-11-01

    RA36 DNA aptamer is a direct anticoagulant prolonging clotting time of human, rabbit, and rat plasma in the thrombin time test. Anticoagulant activity of RA36 is lower than that of recombinant hirudin. During inhibition of human plasma clotting activated with echitox (coagulase from Echis multisquamatus venom), the aptamer presumably binds to meisothrombin exosite I. The sensitivity of human plasma to the aptamer 5-fold surpasses that of rat plasma. Analysis of RA36 binding to coagulase of Agkistrodon halys venom (ancistron) is required for proving the effect of aptamer on polymerization of human fibrinogen. PMID:24319726

  6. Impedimetric thrombin aptasensor based on chemically modified graphenes

    Loo, Adeline Huiling; Bonanni, Alessandra; Pumera, Martin

    2011-12-01

    Highly sensitive biosensors are of high importance to the biomedical field. Graphene represents a promising transducing platform for construction of biosensors. Here for the first time we compare the biosensing performance of a wide set of graphenes prepared by different methods. In this work, we present a simple and label-free electrochemical impedimetric aptasensor for thrombin based on chemically modified graphene (CMG) platforms such as graphite oxide (GPO), graphene oxide (GO), thermally reduced graphene oxide (TR-GO) and electrochemically reduced graphene oxide (ER-GO). Disposable screen-printed electrodes were first modified with chemically modified graphene (CMG) materials and used to immobilize a DNA aptamer which is specific to thrombin. The basis of detection relies on the changes in impedance spectra of redox probe after the binding of thrombin to the aptamer. It was discovered that graphene oxide (GO) is the most suitable material to be used as compared to the other three CMG materials. Furthermore, the optimum concentration of aptamer to be immobilized onto the modified electrode surface was determined to be 10 μM and the linear detection range of thrombin was 10-50 nM. Lastly, the aptasensor was found to demonstrate selectivity for thrombin. Such simply fabricated graphene oxide aptasensor shows high promise for clinical diagnosis of biomarkers and point-of-care analysis.

  7. A Novel Photoelectrochemical Biosensor for Tyrosinase and Thrombin Detection

    Jiexia Chen

    2016-01-01

    Full Text Available A novel photoelectrochemical biosensor for step-by-step assay of tyrosinase and thrombin was fabricated based on the specific interactions between the designed peptide and the target enzymes. A peptide chain with a special sequence which contains a positively charged lysine-labeled terminal, tyrosine at the other end and a cleavage site recognized by thrombin between them was designed. The designed peptide can be fixed on surface of the CdTe quantum dots (QDs-modified indium-tin oxide (ITO electrode through electrostatic attraction to construct the photoelectrochemical biosensor. The tyrosinase target can catalyze the oxidization of tyrosine by oxygen into ortho-benzoquinone residues, which results in a decrease in the sensor photocurrent. Subsequently, the cleavage site could be recognized and cut off by another thrombin target, restoring the sensor photocurrent. The decrease or increase of photocurrent in the sensor enables us to assay tyrosinase and thrombin. Thus, the detection of tyrosinase and thrombin can be achieved in the linear range from 2.6 to 32 μg/mL and from 4.5 to 100 μg/mL with detection limits of 1.5 μg/mL and 1.9 μg/mL, respectively. Most importantly, this strategy shall allow us to detect different classes of enzymes simultaneously by designing various enzyme-specific peptide substrates.

  8. A Novel Photoelectrochemical Biosensor for Tyrosinase and Thrombin Detection

    Chen, Jiexia; Liu, Yifan; Zhao, Guang-Chao

    2016-01-01

    A novel photoelectrochemical biosensor for step-by-step assay of tyrosinase and thrombin was fabricated based on the specific interactions between the designed peptide and the target enzymes. A peptide chain with a special sequence which contains a positively charged lysine-labeled terminal, tyrosine at the other end and a cleavage site recognized by thrombin between them was designed. The designed peptide can be fixed on surface of the CdTe quantum dots (QDs)-modified indium-tin oxide (ITO) electrode through electrostatic attraction to construct the photoelectrochemical biosensor. The tyrosinase target can catalyze the oxidization of tyrosine by oxygen into ortho-benzoquinone residues, which results in a decrease in the sensor photocurrent. Subsequently, the cleavage site could be recognized and cut off by another thrombin target, restoring the sensor photocurrent. The decrease or increase of photocurrent in the sensor enables us to assay tyrosinase and thrombin. Thus, the detection of tyrosinase and thrombin can be achieved in the linear range from 2.6 to 32 ?g/mL and from 4.5 to 100 ?g/mL with detection limits of 1.5 ?g/mL and 1.9 ?g/mL, respectively. Most importantly, this strategy shall allow us to detect different classes of enzymes simultaneously by designing various enzyme-specific peptide substrates. PMID:26805846

  9. Scanning electrochemical microscopy for study of aptamer-thrombin interfacial interactions on gold disk microelectrodes.

    Bai, Huei-Yu; del Campo, F Javier; Tsai, Yu-Chen

    2014-03-01

    A feasibility for the determination of thrombin on gold disk microelectrodes (GDMs) using scanning electrochemical microscopy (SECM) is reported. The assembly process step-by-step of thrombin aptasensor on GDMs is monitored by SECM. SECM analysis reveals the immobilization of thrombin aptamers on GDMs. The interaction between thrombin aptamers and thrombin on GDMs is imaged by SECM with feedback mode using ferrocenemethanol as an electrochemical mediator. The formation of thrombin/thrombin aptamer complex on GDMs results in a decrease in the tip peak current on spatial SECM images. This method is able to linearly and selectively detect thrombin over a linear range from 10(-12) to 10(-5)M with a detection limit of 6.07 fM. PMID:24407695

  10. Recombinant activated factor VII: 30 years of research and innovation.

    Hedner, Ulla

    2015-06-01

    Recombinant activated factor VII (rFVIIa) was initially developed to treat bleeding episodes in patients with congenital haemophilia and inhibitors. The story of its development began in the 1970s, when FVIIa was identified as one of the activated coagulation factors that has minimal potential for inducing thromboembolic side-effects. Extensive research over the last 30 years has greatly increased our knowledge of the characteristics of FVII, its activation, and the mechanisms by which rFVIIa restores haemostasis. In haemophilia, the haemostatic effect of rFVIIa is mediated via binding to thrombin-activated platelets at the site of injury, thereby enhancing thrombin generation also in the absence of factor (F) VIII or FIX. The mechanism of action of rFVIIa has also allowed its successful use in other clinical scenarios characterised by impaired thrombin generation, and its licensed uses have now been extended to acquired haemophilia, congenital FVII deficiency and Glanzmann's thrombasthenia. PMID:26073368

  11. The Importance of Thrombin in Cerebral Injury and Disease

    Harald Krenzlin

    2016-01-01

    Full Text Available There is increasing evidence that prothrombin and its active derivative thrombin are expressed locally in the central nervous system. So far, little is known about the physiological and pathophysiological functions exerted by thrombin in the human brain. Extra-hepatic prothrombin expression has been identified in neuronal cells and astrocytes via mRNA measurement. The actual amount of brain derived prothrombin is expected to be 1% or less compared to that in the liver. The role in brain injury depends upon its concentration, as higher amounts cause neuroinflammation and apoptosis, while lower concentrations might even be cytoprotective. Its involvement in numerous diseases like Alzheimer’s, multiple sclerosis, cerebral ischemia and haemorrhage is becoming increasingly clear. This review focuses on elucidation of the cerebral thrombin expression, local generation and its role in injury and disease of the central nervous system.

  12. Fractal gold modified electrode for ultrasensitive thrombin detection

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

    2012-05-01

    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

  13. The Importance of Thrombin in Cerebral Injury and Disease.

    Krenzlin, Harald; Lorenz, Viola; Danckwardt, Sven; Kempski, Oliver; Alessandri, Beat

    2016-01-01

    There is increasing evidence that prothrombin and its active derivative thrombin are expressed locally in the central nervous system. So far, little is known about the physiological and pathophysiological functions exerted by thrombin in the human brain. Extra-hepatic prothrombin expression has been identified in neuronal cells and astrocytes via mRNA measurement. The actual amount of brain derived prothrombin is expected to be 1% or less compared to that in the liver. The role in brain injury depends upon its concentration, as higher amounts cause neuroinflammation and apoptosis, while lower concentrations might even be cytoprotective. Its involvement in numerous diseases like Alzheimer's, multiple sclerosis, cerebral ischemia and haemorrhage is becoming increasingly clear. This review focuses on elucidation of the cerebral thrombin expression, local generation and its role in injury and disease of the central nervous system. PMID:26761005

  14. Multiple active forms of thrombin. IV. Relative activities of meizothrombins

    The prothrombin activation intermediates meizothrombin and meizothrombin(desF1) (meizothrombin that has been autoproteolyzed to remove fragment 1) have been obtained in a relatively pure, active form with minimal autolysis, making them suitable for enzymatic characterization. When compared at equimolar concentrations, alpha-thrombin, fragment 1.2+ alpha-thrombin, meizothrombin(desF1), and meizothrombin have approximately 100, 100, 10, and 1% activity, respectively, toward the macromolecular substrates factor V, fibrinogen, and platelets. The difference in activity of these four enzymes cannot be attributed to alterations in the catalytic triad, as all four enzymes have nearly identical catalytic efficiency toward the chromogenic substrate S2238. Further, the ability of meizothrombin and meizothrombin(desF1) to activate protein C was 75% of the activity exhibited by alpha-thrombin or fragment 1.2+ alpha-thrombin. All four enzymes bind to thrombomodulin, as judged by the enhanced rate of protein C activation upon preincubation of the enzymes with thrombomodulin. The extent of rate enhancement varied, with meizothrombin/thrombomodulin exhibiting only 50% of the alpha-thrombin/thrombomodulin rate. This difference in rate is not due to a decreased affinity of the meizothrombin for thrombomodulin since the apparent dissociation constants for the alpha-thrombin-thrombomodulin complex and the meizothrombin-thrombomodulin complex are virtually identical. The difference in the observed rate is due in part to the higher Km for protein C exhibited by the meizothrombin-thrombomodulin complex. Incubation of the thrombomodulin-enzyme complex with phospholipid vesicles caused an increase in the protein C activation rates. The kinetic constants for protein C activation in the presence of phospholipid are virtually identical for these enzyme-thrombomodulin complexes

  15. Activation of human factor V by factor Xa and thrombin

    Monkovic, D.D.; Tracy, P.B. (Univ. of Vermont, Burlington (USA))

    1990-02-06

    The activation of human factor V by factor Xa and thrombin was studied by functional assessment of cofactor activity and sodium dodecyl sulfate-polycarylamide gel electrophoresis followed by either autoradiography of {sup 125}I-labeled factor V activation products or Western blot analyses of unlabeled factor V activation products. Cofactor activity was measured by the ability of the factor V/Va peptides to support the activation of prothrombin. The factor Xa catalyzed cleavage of factor V was observed to be time, phospholipid, and calcium ion dependent, yielding a cofactor with activity equal to that of thrombin-activated factor V (factor Va). The cleavage pattern differed markedly from the one observed in the bovine system. The factor Xa activated factor V subunits expressing cofactor activity were isolated and found to consist of peptides of M{sub r} 220,000 and 105,000. Although thrombin cleaved the M{sub r} 220,000 peptide to yield peptides previously shown to be products of thrombin activation, cofactor activity did not increase. N-Terminal sequence analysis confirmed that both factor Xa and thrombin cleave factor V at the same bond to generate the M{sub r} 220,000 peptide. The factor Xa dependent functional assessment of {sup 125}I-labeled factor V coupled with densitometric analyses of the cleavage products indicated that the cofactor activity of factor Xa activated factor V closely paralleled the appearance of the M{sub r} 220,000 peptide. The data indicate that factor Xa is as efficient an enzyme toward factor V as thrombin.

  16. Creatine kinase, an ATP-generating enzyme, is required for thrombin receptor signaling to the cytoskeleton

    Mahajan, Vinit B.; Pai, Karnire S.; Lau, Alice; Cunningham, Dennis D.

    2000-01-01

    Thrombin orchestrates cellular events after injury to the vascular system and extravasation of blood into surrounding tissues. The pathophysiological response to thrombin is mediated by protease-activated receptor-1 (PAR-1), a seven-transmembrane G protein-coupled receptor expressed in the nervous system that is identical to the thrombin receptor in platelets, fibroblasts, and endothelial cells. Once activated by thrombin, PAR-1 induces rapid and dramatic changes i...

  17. Aptamer-Based Enzyme Capture Assay for Measurement of Plasma Thrombin Levels.

    Müller, Jens; Becher, Tobias; Mayer, Günter; Pötzsch, Bernd

    2016-01-01

    The quantification of circulating thrombin is a valuable tool to accurately assess the activity of the blood coagulation system. Here, we describe the combined application of the thrombin-specific reversible active-site inhibitor argatroban and the DNA-aptamer HD1-22 for conduction of an enzyme capture assay for reliable measurement of plasma thrombin levels. PMID:26552826

  18. Increased anticoagulant activity of thrombin-binding DNA aptamers by nanoscale organization on DNA nanostructures

    Rangnekar, Abhijit; Zhang, Alex M.; Shiyuan Li, Susan; M. Bompiani, Kristin; Hansen, Majken Nørgaard; Gothelf, Kurt Vesterager; Sullenger, Bruce A.; Labean, Thomas H.

    2012-01-01

    Control over thrombin activity is much desired to regulate blood clotting in surgical and therapeutic situations. Thrombin-binding RNA and DNA aptamers have been used to inhibit thrombin activity and thus the coagulation cascade. Soluble DNA aptamers, as well as two different aptamers tethered by...

  19. New Approaches to the Role of Thrombin in Acute Coronary Syndromes: Quo Vadis Bivalirudin, a Direct Thrombin Inhibitor?

    Esteve-Pastor, María Asunción; Hernández-Romero, Diana; Valdés, Mariano; Marín, Francisco

    2016-01-01

    The pathophysiology of acute coronary syndrome (ACS) involves platelet activation and thrombus formation after the rupture of atherosclerotic plaques. Thrombin is generated at the blood-plaque interface in association with cellular membranes on cells and platelets. Thrombin also amplifies the response to the tissue injury, coagulation and platelet response, so the treatment of ACS is based on the combined use of both antiplatelet (such as aspirin, clopidogrel, prasugrel and ticagrelor) and antithrombotic drugs (unfractionated heparin, enoxaparin, fondaparinux and bivalirudin). Bivalirudin competitively inhibits thrombin with high affinity, a predictable response from its linear pharmacokinetics and short action. However, a present remarkable controversy exists between the latest main Guidelines in Clinical Practice and the key trials evaluating the use of bivalirudin in ACS. The aim of this review is to update the development of bivalirudin, including pharmacological properties, obtained information from clinical trials evaluating efficacy and safety of bivalirudin in ACS; as well as the recommendations of clinical Guidelines. PMID:26927051

  20. AI Topics

    Buchanan, Bruce G.; Glick, Jonathan

    2002-01-01

    The debut of the AI in the News column elsewhere in this issue of AI Magazine created a good opportunity to introduce the professional community to the AI Topics web site, home of the AI in the news virtual page. Although AI Topics is designed for the lay public, it serves a much larger audience.

  1. Inhibition of Cellular Adhesion by Immunological Targeting of Osteopontin Neoepitopes Generated through Matrix Metalloproteinase and Thrombin Cleavage.

    Jrets, Alexander; Le Bras, Marie; Staffler, Gnther; Stein, Gesine; Leitner, Lukas; Neuhofer, Angelika; Tardelli, Matteo; Turkof, Edvin; Zeyda, Maximilian; Stulnig, Thomas M

    2016-01-01

    Osteopontin (OPN), a secreted protein involved in inflammatory processes and cancer, induces cell adhesion, migration, and activation of inflammatory pathways in various cell types. Cells bind OPN via integrins at a canonical RGD region in the full length form as well as to a contiguous cryptic site that some have shown is unmasked upon thrombin or matrix metalloproteinase cleavage. Thus, the adhesive capacity of osteopontin is enhanced by proteolytic cleavage that may occur in inflammatory conditions such as obesity, atherosclerosis, rheumatoid arthritis, tumor growth and metastasis. Our aim was to inhibit cellular adhesion to recombinant truncated proteins that correspond to the N-terminal cleavage products of thrombin- or matrix metalloproteinase-cleaved OPN in vitro. We specifically targeted the cryptic integrin binding site with monoclonal antibodies and antisera induced by peptide immunization of mice. HEK 293 cells adhered markedly stronger to truncated OPN proteins than to full length OPN. Without affecting cell binding to the full length form, the raised monoclonal antibodies specifically impeded cellular adhesion to the OPN fragments. Moreover, we show that the peptides used for immunization were able to induce antisera, which impeded adhesion either to all OPN forms, including the full-length form, or selectively to the corresponding truncated recombinant proteins. In conclusion, we developed immunological tools to selectively target functional properties of protease-cleaved OPN forms, which could find applications in treatment and prevention of various inflammatory diseases and cancers. PMID:26840958

  2. A Guided Mode Resonance Aptasensor for Thrombin Detection

    Wen-Yih Chen

    2011-09-01

    Full Text Available Recent developments in aptamers have led to their widespread use in analytical and diagnostic applications, particularly for biosensing. Previous studies have combined aptamers as ligands with various sensors for numerous applications. However, merging the aptamer developments with guided mode resonance (GMR devices has not been attempted. This study reports an aptasensor based home built GMR device. The 29-mer thrombin aptamer was immobilized on the surface of a GMR device as a recognizing ligand for thrombin detection. The sensitivity reported in this first trial study is 0.04 nm/?M for thrombin detection in the concentration range from 0.25 to 1 ?M and the limit of detection (LOD is 0.19 ?M. Furthermore, the binding affinity constant (Ka measured is in the range of 106 M?1. The investigation has demonstrated that such a GMR aptasensor has the required sensitivity for the real time, label-free, in situ detection of thrombin and provides kinetic information related to the binding.

  3. The thrombin binding aptamer GGTTGGTGTGGTTGG forms a bimolecular guanine tetraplex

    Fialová, Markéta; Kypr, Jaroslav; Vorlíčková, Michaela

    2006-01-01

    Roč. 344, 1 (2006), s. 50-54. ISSN 0006-291X R&D Projects: GA AV ČR(CZ) IAA4004201 Institutional research plan: CEZ:AV0Z50040507 Keywords : DNA tetraplex * thrombin binding aptamer * CD spectroscopy Subject RIV: BO - Biophysics Impact factor: 2.855, year: 2006

  4. Thrombin induces rapid PAR1-mediated non-classical FGF1 release

    Thrombin induces cell proliferation and migration during vascular injury. We report that thrombin rapidly stimulated expression and release of the pro-angiogenic polypeptide fibroblast growth factor 1 (FGF1). Thrombin failed to induce FGF1 release from protease-activated receptor 1 (PAR1) null fibroblasts, indicating that this effect was dependent on PAR1. Similarly to thrombin, FGF1 expression and release were induced by TRAP, a specific oligopeptide agonist of PAR1. These results identify a novel aspect of the crosstalk between FGF and thrombin signaling pathways which both play important roles in tissue repair and angiogenesis

  5. Testosterone Topical

    ... not apply any testosterone topical products to your penis or scrotum or to skin that has sores, ... are severe or do not go away: breast enlargement and/or pain decreased sexual desire acne depression ...

  6. Tacrolimus Topical

    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 ...

  7. Diphenhydramine Topical

    Diphenhydramine, an antihistamine, is used to relieve the itching of insect bites, sunburns, bee stings, poison ivy, ... Diphenhydramine topical comes in cream, lotion, gel, and spray to be applied to the skin. It is ...

  8. Ciclopirox Topical

    ... treatment. Use the applicator brush attached to the bottle cap to apply ciclopirox topical solution evenly to all ... you can reach these areas. Wipe off the bottle cap and neck and replace the cap tightly on ...

  9. Interactions of liver Grp78 and Escherichia coli recombinant Grp78 with ATP: multiple species and disaggregation.

    A. Carlino; Toledo, H; Skaleris, D; DeLisio, R; Weissbach, H; Brot, N

    1992-01-01

    The hamster gene encoding the 78-kDa glucose-regulated protein (Grp78) was expressed in Escherichia coli as a fusion protein with glutathione S-transferase. After induction with isopropyl beta-D-thiogalactopyranoside, the recombinant Grp78 was purified to homogeneity by affinity column chromatography of the fusion protein followed by thrombin cleavage. The purified recombinant protein was compared with liver Grp78 for its ability to interact with ATP. Like liver Grp78, the recombinant protein...

  10. Cell biology of mitotic recombination

    Lisby, Michael; Rothstein, Rodney

    2015-01-01

    Homologous recombination provides high-fidelity DNA repair throughout all domains of life. Live cell fluorescence microscopy offers the opportunity to image individual recombination events in real time providing insight into the in vivo biochemistry of the involved proteins and DNA molecules as...... well as the cellular organization of the process of homologous recombination. Herein we review the cell biological aspects of mitotic homologous recombination with a focus on Saccharomyces cerevisiae and mammalian cells, but will also draw on findings from other experimental systems. Key topics of this...

  11. Evaluation of DNA aptamers directed to thrombin as potential thrombus imaging agents

    Two DNA aptamers directed against two separate exosites on human ?-thrombin were evaluated for thrombus-imaging potential. Aptamer ODN 1 is directed to the thrombin substrate binding site (exosite 1). Our finding that ODN 1 competes with fibrin for binding to exosite 1 on thrombin suggests that ODN 1 will not be useful for thrombus imaging. Aptamer ODN 2 is directed against the thrombin heparin binding site (exosite 2). ODN 2 bound to model thrombi that were formed either by clotting purified fibrinogen with thrombin, or by recalcifying citrated plasma. As the thrombin content of thrombi was increased the rate of ODN 2 uptake into preformed thrombi increased, whereas the rate of release of ODN 2 out of preformed thrombi decreased. This in vitro data suggested that ODN 2 might be useful for thrombus imaging because it can bind to exosite 2 on fibrin-bound thrombin. However, in a rabbit jugular vein model using thrombus supplemented with human thrombin, ODN 2 uptake was equal to the ovalbumin control, and did not reflect thrombin content. While the in vitro results with ODN 2 were consistent with thrombus imaging, the rapid clearance of ODN 2 from circulation, combined with slow mass transfer in the clot, seem to work against in vivo thrombin-dependent imaging or washout analysis

  12. A novel histochemical method for the visualization of thrombin activity in the nervous system.

    Bushi, D; Gera, O; Kostenich, G; Shavit-Stein, E; Weiss, R; Chapman, J; Tanne, D

    2016-04-21

    Although thrombin has an important role in both central and peripheral nerve diseases, characterization of the anatomical distribution of its proteolytic activity has been limited by available methods. This study presents the development, challenges, validation and implementation of a novel histochemical method for visualization of thrombin activity in the nervous system. The method is based on the cleavage of the substrate, Boc-Asp(OBzl)-Pro-Arg-4M?NA by thrombin to liberate free 4-methoxy-2-naphthylamine (4M?NA). In the presence of 5-nitrosalicylaldehyde, free 4M?NA is captured, yielding an insoluble yellow fluorescent precipitate which marks the site of thrombin activity. The sensitivity of the method was determined in vitro using known concentrations of thrombin while the specificity was verified using a highly specific thrombin inhibitor. Using this method we determined the spatial distribution of thrombin activity in mouse brain following transient middle cerebral artery occlusion (tMCAo) and in mouse sciatic nerve following crush injury. Fluorescence microscopy revealed well-defined thrombin activity localized to the right ischemic hemisphere in cortical areas and in the striatum compared to negligible thrombin activity contralaterally. The histochemical localization of thrombin activity following tMCAo was in good correlation with the infarct areas per triphenyltetrazolium chloride staining and to thrombin activity measured biochemically in tissue punches (8535 and 203mU/ml, in the cortical and striatum areas respectively, compared to 72 and 132mU/ml, in the corresponding contralateral areas; meanSEM; p<0.05). In addition, 24h following crush injury, focal areas of highly elevated thrombin activity were detected in teased sciatic fibers. This observation was supported by the biochemical assay and western blot technique. The histochemical method developed in this study can serve as an important tool for studying the role of thrombin in physiological and pathological conditions. PMID:26851772

  13. Thrombin aptasensing with inherently electroactive graphene oxide nanoplatelets as labels

    Loo, Adeline Huiling; Bonanni, Alessandra; Pumera, Martin

    2013-05-01

    Graphene and its associated materials are commonly used as the transducing platform in biosensing. We propose a different approach for the application of graphene in biosensing. Here, we utilized graphene oxide nanoplatelets as the inherently electroactive labels for the aptasensing of thrombin. The basis of detection lies in the ability of graphene oxide to be electrochemically reduced, thereby providing a well-defined reduction wave; one graphene oxide nanoplatelet of dimension 50 × 50 nm can provide a reduction signal by accepting ~22 000 electrons. We demonstrate that by using graphene oxide nanoplatelets as an inherently electroactive label, we can detect thrombin in the concentration range of 3 pM-0.3 μM, with good selectivity of the aptamer towards interferences by bovine serum albumin, immunoglobulin G and avidin. Therefore, the inherently electroactive graphene oxide nanoplatelets are a material which can serve as an electroactive label, in a manner similar to metallic nanoparticles.

  14. Effect of Iron Chelators on Methemoglobin and Thrombin Preconditioning

    Chen-Roetling, Jing; Sinanan, Jesse; Regan, Raymond F.

    2012-01-01

    Cell loss immediately adjacent to an intracerebral hemorrhage may be mediated in part by the toxicities of extracellular hemoglobin (Hb) and thrombin. However, at low concentrations, these proteins induce tolerance to hemin and iron that may limit further peri-hematomal injury as erythrocyte lysis progresses. The mechanisms mediating these preconditioning effects have not been completely defined, but increased expression of both heme oxygenase (HO)-1 and iron binding proteins likely contribut...

  15. Thrombin Receptor and Ventricular Arrhythmias after Acute Myocardial Infarction

    Tang, Lilong; Deng, Chunyu; Long, Ming; Tang, Anli; Wu, Shulin; Dong, Yugang; Saravolatz, Louis D.; Gardin, Julius M.

    2008-01-01

    The mechanism mediating the development of ventricular arrhythmia (VA) after acute myocardial infarction (AMI) is still uncertain. Thrombin receptor (TR) activation has been proven to be arrhythmogenic in many other situations, and we hypothesize that it may participate in the genesis of post-AMI VA. Using a left coronary artery ligation rat model of AMI, we found that a local injection of hirudin into the left ventricle (LV) significantly reduced the ratio of VA durations to infarction sizin...

  16. An electrochemical aptasensor electrocatalyst for detection of thrombin.

    Tian, Rong; Chen, Xiaojun; Li, Qingwen; Yao, Cheng

    2016-05-01

    This work reports a novel signal amplification strategy based on three-dimensional ordered macroporous C60-poly(3,4-ethylenedioxythiophene)-1-butyl-3-methylimidazolium hexafluorophosphate (3DOM C60-PEDOT-[BMIm][BF6]) for ultrasensitive detection of thrombin by cascade catalysis of Au-PEDOT@SiO2 microspheres and alcohol dehydrogenase (ADH). Au-PEDOT@SiO2 microspheres were constructed not only as nanocarriers to anchor the large amounts of secondary thrombin aptamers but also as nanocatalysts to catalyze the oxidation of ethanol efficiently. Significantly, the electrochemical signal was greatly enhanced based on cascade catalysis: First, ADH catalyzed the oxidation of ethanol to acetaldehyde with the concomitant generation of NADH in the presence of β-nicotinamide adenine dinucleotide hydrate (NAD(+)). Then, gold nanoparticles (AuNPs) as nanocatalysts could effectively catalyze NADH to produce NAD(+) with the help of PEDOT as redox probe. Under the optimal conditions, the proposed aptasensor exhibits a linear range of 2 × 10(-13) to 2 × 10(-8) M with a low detection limit of 2 × 10(-14) M for thrombin detection and shows high sensitivity and good specificity. PMID:26869084

  17. Stabilization of the E* Form Turns Thrombin into an Anticoagulant

    Bah, Alaji; Carrell, Christopher J.; Chen, Zhiwei; Gandhi, Prafull S.; Di Cera, Enrico; (WU-MED)

    2009-07-31

    Previous studies have shown that deletion of nine residues in the autolysis loop of thrombin produces a mutant with an anticoagulant propensity of potential clinical relevance, but the molecular origin of the effect has remained unresolved. The x-ray crystal structure of this mutant solved in the free form at 1.55 {angstrom} resolution reveals an inactive conformation that is practically identical (root mean square deviation of 0.154 {angstrom}) to the recently identified E* form. The side chain of Trp215 collapses into the active site by shifting >10 {angstrom} from its position in the active E form, and the oxyanion hole is disrupted by a flip of the Glu192-Gly193 peptide bond. This finding confirms the existence of the inactive form E* in essentially the same incarnation as first identified in the structure of the thrombin mutant D102N. In addition, it demonstrates that the anticoagulant profile often caused by a mutation of the thrombin scaffold finds its likely molecular origin in the stabilization of the inactive E* form that is selectively shifted to the active E form upon thrombomodulin and protein C binding.

  18. Thrombin Activity Propagates in Space During Blood Coagulation as an Excitation Wave

    Dashkevich, N.M.; Ovanesov, M.V.; Balandina, A.N.; Karamzin, S.S.; Shestakov, P.I.; Soshitova, N.P.; Tokarev, A.A.; Panteleev, M.A.; F. I. Ataullakhanov

    2012-01-01

    Injury-induced bleeding is stopped by a hemostatic plug formation that is controlled by a complex nonlinear and spatially heterogeneous biochemical network of proteolytic enzymes called blood coagulation. We studied spatial dynamics of thrombin, the central enzyme of this network, by developing a fluorogenic substrate-based method for time- and space-resolved imaging of thrombin enzymatic activity. Clotting stimulation by immobilized tissue factor induced localized thrombin activity impulse t...

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

    Martínez-Sales, Vicenta; Vila, Virtudes; Ferrando, Marcos; Reganon, Edelmiro

    2010-01-01

    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...

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

    Herrera Maria

    2006-04-01

    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.

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

    Vila, Virtudes; Ferrando, Marcos; Reganon, Edelmiro

    2010-01-01

    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. PMID:21052830

  2. Baicalin protects against thrombin induced cell injury in SH-SY5Y cells

    Ju, Xiao-Ning; Mu, Wei-Na; Liu, Yuan-tao; Wang, Mei-Hong; KONG, FENG; Sun, Chao; Zhou, Qing-Bo

    2015-01-01

    Baicalin, an extract from the dried root of Scutellaria baicalensis Georgi, was shown to be neuroprotective. However, the precise mechanisms are incompletely known. In this study, we determined the effect of baicalin on thrombin induced cell injury in SH-SY5Y cells, and explored the possible mechanisms. SH-SY5Y cells was treated with thrombin alone or pre-treated with baicalin (5, 10, 20 μM) for 2 h followed by thrombin treatment. Cells without thrombin and baicalin treatment were used as con...

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

    Koh, Young Hwan [Boramae Hospital, Seoul (Korea, Republic of); Kim, Hak Soo; Kim, Hyung Sik; Min, Seung Kee [Gachon Medical School, Incheon (Korea, Republic of)

    2005-09-15

    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

  4. Nonradiative recombination in semiconductors

    Abakumov, VN; Yassievich, IN

    1991-01-01

    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

  5. Recombination instability

    D'Angelo, N.

    1967-01-01

    A recombination instability is considered which may arise in a plasma if the temperature dependence of the volume recombination coefficient, alpha, is sufficiently strong. Two cases are analyzed: (a) a steady-state plasma produced in a neutral gas by X-rays or high energy electrons; and (b) an...

  6. Evaluation of Thrombin Generation Assay in Patients With Hemophilia.

    Haghpanah, Sezaneh; Bazrafshan, Asghar; Silavizadeh, Samir; Dehghani, Javad; Afrasiabi, Abdolreza; Karimi, Mehran

    2016-05-01

    We evaluated the correlation between thrombin generation (TG) parameters with bleeding symptoms and disease severity in patients with hemophilia. In this cross-sectional study, 59 patients with hemophilia without inhibitors and regardless of their severity were randomly selected from southern Iran and TG assays were conducted. Bleeding score (BS) was calculated by performing a clinical evaluation using Tosetto questionnaire. Only lag time showed a statistically significant correlation with BS (rs = .316,P= .016). All TG parameters except peak showed association with disease severity (Phemophilia, the majority of TG parameters were significantly associated with factor activity level and disease severity. PMID:25354749

  7. Thrombin and fibrinogen ?' impact clot structure by marked effects on intrafibrillar structure and protofibril packing.

    Domingues, Marco M; Macrae, Fraser L; Duval, Cdric; McPherson, Helen R; Bridge, Katherine I; Ajjan, Ramzi A; Ridger, Victoria C; Connell, Simon D; Philippou, Helen; Arins, Robert A S

    2016-01-28

    Previous studies have shown effects of thrombin and fibrinogen ?' on clot structure. However, structural information was obtained using electron microscopy, which requires sample dehydration. Our aim was to investigate the role of thrombin and fibrinogen ?' in modulating fibrin structure under fully hydrated conditions. Fibrin fibers were studied using turbidimetry, atomic force microscopy, electron microscopy, and magnetic tweezers in purified and plasma solutions. Increased thrombin induced a pronounced decrease in average protofibril content per fiber, with a relatively minor decrease in fiber size, leading to the formation of less compact fiber structures. Atomic force microscopy under fully hydrated conditions confirmed that fiber diameter was only marginally decreased. Decreased protofibril content of the fibers produced by high thrombin resulted in weakened clot architecture as analyzed by magnetic tweezers in purified systems and by thromboelastometry in plasma and whole blood. Fibers produced with fibrinogen ?' showed reduced protofibril packing over a range of thrombin concentrations. High-magnification electron microscopy demonstrated reduced protofibril packing in ?' fibers and unraveling of fibers into separate protofibrils. Decreased protofibril packing was confirmed in plasma for high thrombin concentrations and fibrinogen-deficient plasma reconstituted with ?' fibrinogen. These findings demonstrate that, in fully hydrated conditions, thrombin and fibrinogen ?' have dramatic effects on protofibril content and that protein density within fibers correlates with strength of the fibrin network. We conclude that regulation of protofibril content of fibers is an important mechanism by which thrombin and fibrinogen ?' modulate fibrin clot structure and strength. PMID:26608329

  8. Evaluation of Potential Thrombin Inhibitors from the White Mangrove (Laguncularia racemosa (L. C.F. Gaertn.

    Caroline Fabri Bittencourt Rodrigues

    2015-07-01

    Full Text Available The aim of this work was to verify the effects of methanol (MeOH and hydroalcoholic (HA extracts and their respective partition phases obtained from white mangrove (Laguncularia racemosa (L. C.F. Gaertn. leaves on human thrombin activity. Among the extracts and phases tested, only the ethyl acetate and butanolic partitions significantly inhibited human thrombin activity and the coagulation of plasma in the presence of this enzyme. Chromatographic analyses of the thrombin samples incubated with these phases revealed that different compounds were able to interact with thrombin. The butanolic phase of the MeOH extract had the most potent inhibitory effects, reducing enzymatic activity and thrombin-induced plasma coagulation. Two glycosylated flavonoids in this partition were identified as the most potent inhibitors of human thrombin activity, namely quercetin-3-O-arabinoside (QAra and quercetin-3-O-rhamnoside (Qn. Chromatographic analyses of thrombin samples incubated with these flavonoids demonstrated the chemical modification of this enzyme, suggesting that the MeOH extract contained other compounds that both induced structural changes in thrombin and diminished its activity. In this article, we show that despite the near absence of the medical use of mangrove compounds, this plant contains natural compounds with potential therapeutic applications.

  9. Detection of thrombin using an excimer aptamer switch labeled with dual pyrene molecules.

    Zhao, Qiang; Cheng, Lin

    2013-10-01

    We constructed an excimer aptamer probe containing one pyrene molecule at each end of a DNA aptamer to achieve the detection of thrombin, which binds to the heparin-binding site of thrombin with high binding affinity. The specific binding of thrombin to the excimer aptamer probe brought the two pyrene molecules at the termini of the duplex of the aptamer into close proximity, generating an excimer. The excimer emitted a distinct fluorescence peak, and fluorometric measurement of excimer allowed the sensitive detection of thrombin. The effects of experimental conditions like pH, ionic strength, and cations were investigated and optimized. The detection limit for thrombin was about 42 pM. This aptamer switch has potential in the study of molecular interactions and protein sensing with other switch-based detection strategy. PMID:23912830

  10. Thrombin-specific inactivation of endothelial cell derived plasminogen activator

    Although thrombin (T) has diverse functions in the overall hemostatic mechanism, relatively little is known about its direct effect on components of the fibrinolytic enzyme system. The authors have investigated the interaction of T with plasminogen activators (PA) derived from bovine aortic endothelial cells (EC) in culture (2-5th passage, preconfluent monolayers). Varying concentrations of purified bovine or human thrombin were added to EC-conditioned media (CM). CM + T mixtures were assayed at various times for PA activity using purified plasminogen and a sensitive 125I-fibrinogenolytic or caseinolytic assay. T (5 nM), but not plasmin or trypsin at equivalent concentrations, resulted in a time-dependent inhibition of the PA activity in CM. T had no effect on the PA activity of urokinase, streptokinase or preformed plasmin. The ability of T to inactivate the EC-derived PA was abolished by prior treatment of T with active site-directed reagents. SDS-PAGE and zymography with copolymerized fibrinogen and plasminogen revealed further specificity in that only one of the multiple-molecular weight forms of PA present in EC-CM was inactivated by T. The authors conclude that in a highly specific fashion, T inactivates the predominant PA present in EC-CM by limited proteolysis. Thus, another potentially important function of T is suggested which may have particular significance in the temporal regulation of coagulation and fibrinolysis at the blood-endothelium interface

  11. Effects of Aerobic Capacity on Thrombin-Induced Hydrocephalus and White Matter Injury.

    Ni, Wei; Gao, Feng; Zheng, Mingzhe; Koch, Lauren G; Britton, Steven L; Keep, Richard F; Xi, Guohua; Hua, Ya

    2016-01-01

    We have previously shown that intracerebral hemorrhage-induced brain injury is less in rats bred for high aerobic capacity (high capacity runners; HCR) compared with those bred for low aerobic capacity (low capacity runners; LCRs). Thrombin, an essential component in the coagulation cascade, is produced after cerebral hemorrhage. Intraventricular injection of thrombin causes significant hydrocephalus and white matter damage. In the present study, we examined the effect of exercise capacity on thrombin-induced hydrocephalus and white matter damage. Mid-aged (13-month-old) female LCRs (n = 13) and HCRs (n = 12) rats were used in this study. Rats received an intraventricular injection of thrombin (3 U, 50 μl). All rats underwent magnetic resonance imaging (MRI) at 24 h and were then euthanized for brain histology and Western blot. The mortalities were 20 % in LCRs and 33 % in HCRs after thrombin injection (p > 0.05). No rats died after saline injection. Intraventricular thrombin injection resulted in hydrocephalus and periventricular white matter damage as determined on MRI. In LCR rats, thrombin induced significant ventricle enlargement (23.0 ± 2.3 vs12.8 ± 1.9 mm(3) in LCR saline group; p rats thrombin induced less ventricular enlargement (17.3 ± 3.9 vs 23.0 ± 2.3 mm(3) in LCRs, p rats, there was also upregulation of heat shock protein-32, a stress marker, and microglial activation in the periventricular white matter. These changes were significantly reduced in HCR rats. Intraventricular injection of thrombin caused more white matter damage and hydrocephalus in rats with low aerobic capacity. A differential effect of thrombin may contribute to differences in the effects of cerebral hemorrhage with aerobic capacity. PMID:26463978

  12. Topical haemostatic agents for skin wounds: a systematic review

    Ubbink Dirk T

    2011-07-01

    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.

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

    Ni Ainle, Fionnuala

    2009-08-20

    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.

  14. Thrombin-inhibiting nanoparticles rapidly constitute versatile and detectable anticlotting surfaces

    Restoring an antithrombotic surface to suppress ongoing thrombosis is an appealing strategy for treatment of acute cardiovascular disorders such as erosion of atherosclerotic plaque. An antithrombotic surface would present an alternative to systemic anticoagulation with attendant risks of bleeding. We have designed thrombin-targeted nanoparticles (NPs) that bind to sites of active clotting to extinguish local thrombin activity and inhibit platelet deposition while exhibiting only transient systemic anticoagulant effects. Perfluorocarbon nanoparticles (PFC NP) were functionalized with thrombin inhibitors (either D-phenylalanyl-L-prolyl-L-arginyl-chloromethyl ketone or bivalirudin) by covalent attachment of more than 15 000 inhibitors to each PFC NP. Fibrinopeptide A (FPA) ELISA demonstrated that thrombin-inhibiting NPs prevented cleavage of fibrinogen by both free and clot-bound thrombin. Magnetic resonance imaging (MRI) confirmed that a layer of thrombin-inhibiting NPs prevented growth of clots in vitro. Thrombin-inhibiting NPs were administered in vivo to C57BL6 mice subjected to laser injury of the carotid artery. NPs significantly delayed thrombotic occlusion of the artery, whereas an equivalent bolus of free inhibitor was ineffective. For thrombin-inhibiting NPs, only a short-lived (∼10 min) systemic effect on bleeding time was observed, despite prolonged clot inhibition. Imaging and quantification of in vivo antithrombotic NP layers was demonstrated by MRI of the PFC NP. 19F MRI confirmed colocalization of particles with arterial thrombi, and quantitative 19F spectroscopy demonstrated specific binding and retention of thrombin-inhibiting NPs in injured arteries. The ability to rapidly form and image a new antithrombotic surface in acute vascular syndromes while minimizing risks of bleeding would permit a safer method of passivating active lesions than current systemic anticoagulant regimes. (paper)

  15. Thrombostatin FM compounds: direct thrombin inhibitors - mechanism of action in vitro and in vivo

    Nieman, M T; Burke, F; Warnock, M; Zhou, Y; Sweigart, J; Chen, A; Ricketts, D; Lucchesi, B R; Chen, Z; Cera, E Di; Hilfinger, J; Kim, J S; Mosberg, H I; Schmaier, A H [Case Western; (Michigan); (TSRL); (WU-MED)

    2008-04-29

    Novel pentapeptides called Thrombostatin FM compounds consisting mostly of D-isomers and unusual amino acids were prepared based upon the stable angiotensin converting enzyme breakdown product of bradykinin - RPPGF. These peptides are direct thrombin inhibitors prolonging the thrombin clotting time, activated partial thromboplastin time, and prothrombin time at ≥0.78, 1.6, and 1.6 μm, respectively. They competitively inhibit α-thrombin-induced cleavage of a chromogenic substrate at 4.4--8.2 μm. They do not significantly inhibit plasma kallikrein, factor (F) XIIa, FXIa, FIXa, FVIIa-TF, FXa, plasmin or cathepsin G. One form, FM19 [rOicPaF(p-Me)], blocks α-thrombin-induced calcium flux in fibroblasts with an IC50 of 6.9 ± 1.2 μm. FM19 achieved 100% inhibition of threshold α- or γ-thrombin-induced platelet aggregation at 8.4 ± 4.7 μm and 16 ± 4 μm, respectively. The crystal structure of thrombin in complex with FM19 shows that the N-terminal D-Arg retrobinds into the S1 pocket, its second residue Oic interacts with His-57, Tyr-60a and Trp-60d, and its C-terminal p-methyl Phe engages thrombin's aryl binding site composed of Ile-174, Trp-215, and Leu-99. When administered intraperitoneal, intraduodenal, or orally to mice, FM19 prolongs thrombin clotting times and delays carotid artery thrombosis. FM19, a low affinity reversible direct thrombin inhibitor, might be useful as an add-on agent to address an unmet need in platelet inhibition in acute coronary syndromes in diabetics and others who with all current antiplatelet therapy still have reactive platelets.

  16. Improved thrombin binding aptamer by incorporation of a single unlocked nucleic acid monomer

    Pasternak, Anna; Hernandez, Frank J; Rasmussen, Lars Melholt; Vester, Birte; Wengel, Jesper

    2011-01-01

    that a UNA monomer is allowed in many positions of the aptamer without significantly changing the thrombin-binding properties. The biological effect of a selection of the modified aptamers was tested by a thrombin time assay and showed that most of the UNA-modified TBAs possess anticoagulant properties......A 15-mer DNA aptamer (named TBA) adopts a G-quadruplex structure that strongly inhibits fibrin-clot formation by binding to thrombin. We have performed thermodynamic analysis, binding affinity and biological activity studies of TBA variants modified by unlocked nucleic acid (UNA) monomers. UNA...

  17. Thrombin promotes epithelial ovarian cancer cell invasion by inducing epithelial-mesenchymal transition

    Zhong, Yi-Cun; Zhang, Ting; Di, Wen; LI, WEI-PING

    2013-01-01

    Objective Over-expression of thrombin in ovarian cancer cells is associated with poor prognosis. In this study, we investigated the role of thrombin in inducing epithelial-mesenchymal transition (EMT) in SKOV3 epithelial ovarian cancer cells. Methods After thrombin treatment SKOV3 cells were subjected to western blots, reverse-transcription PCR, and enzyme-linked immunosorbent assay to quantify EMT-related proteins, mRNA expression of SMAD2, DKK1, and sFRP1, and the secretion of matrix metall...

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

    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)

  19. Pseudoaneurysm After Spontaneous Rupture of Renal Angiomyolipoma in Tuberous Sclerosis: Successful Treatment with Percutaneous Thrombin Injection

    We report a case of a large perinephric pseudoaneurysm due to spontaneous rupture of renal angiomyolipoma, occluded by percutaneous thrombin injection under ultrasound guidance in a young woman affected by tuberous sclerosis

  20. Fibrinolytic action of an enzyme preparation covalently bound with modified thrombin

    It was pointed out previously that modification of thrombin at the tryptophan, tyrosine, arginine and lysine residues impairs its affinity for fibrinogen. Since a long binding site of macromolecular substrate in the thrombin molecule is responsible for binding of the enzyme with the platelet membrane also, it is probably preferable to carry out the modification at other amino acid residues. The purpose of this paper was to confirm experimentally the validity of this approach to the targeted modification of alpha-thrombin in order to obtain a protein polymer matrix with affinity for centers of thrombus formation. Technetium 99m was used as a label in assessing the ability of the modified thrombin to destroy the fibrin clot

  1. An Investigation of the Characteristics of the Enzyme Thrombin, Suitable for Classwork

    Blofield, B. Ann

    1972-01-01

    Shows how a simple investigation of the enzyme, thrombin, can provide a series of experiments giving information on enzyme characteristics. The results also provide a basis for discussion of the coagulation mechanism and related phenomena. (Author/AL)

  2. Plasma from chronic liver disease subjects exhibit differential ability to generate thrombin.

    Yang, Zhineng J; Sheth, Siddharth H; Smith, Chad H; Schmotzer, Amy R; Lippello, Anita L; Al-Khafaji, Ali; Chopra, Kapil B; Smith, Roy E

    2015-10-01

    Liver fibrosis in chronic liver disease (CLD) results in complex alterations in procoagulant and anticoagulant proteins. Although an elevated international normalized ratio (INR) is a prominent feature of progressive fibrosis, the utility of the INR to accurately reflect the net effect of these changes on the coagulation system is uncertain. In subjects with CLD, elevated INRs have been observed in both bleeding and thrombotic complications, suggesting limitations of the INR in characterizing the coagulation status. Unlike the INR, which is preferentially sensitive to the extrinsic pathway, the direct measurement of thrombin generation better captures the global coagulation cascade. We conducted a pilot study measuring the INR, chromogenic factor X and thrombin generation in CLD subjects and compared them with control subjects and subjects on warfarin anticoagulation. We observed a large interquartile range in thrombin generation among compensated CLD subjects across a narrow INR range, suggesting that the INR is a suboptimal surrogate measure of thrombin generation in CLD subjects. PMID:26200653

  3. Thrombin inhibits the anti-myeloperoxidase and ferroxidase functions of ceruloplasmin: relevance in rheumatoid arthritis.

    Sokolov, Alexej V; Acquasaliente, Laura; Kostevich, Valeria A; Frasson, Roberta; Zakharova, Elena T; Pontarollo, Giulia; Vasilyev, Vadim B; De Filippis, Vincenzo

    2015-09-01

    Human ceruloplasmin (CP) is a multifunctional copper-binding protein produced in the liver. CP oxidizes Fe(2+) to Fe(3+), decreasing the concentration of Fe(2+) available for generating harmful oxidant species. CP is also a potent inhibitor of leukocyte myeloperoxidase (MPO) (Kd=130nM), a major source of oxidants in vivo. Rheumatoid arthritis (RA) is an inflammatory autoimmune disease affecting flexible joints and characterized by activation of both inflammatory and coagulation processes. Indeed, the levels of CP, MPO, and thrombin are markedly increased in the synovial fluid of RA patients. Here we show that thrombin cleaves CP in vitro at (481)Arg-Ser(482) and (887)Lys-Val(888) bonds, generating a nicked species that retains the native-like fold and the ferroxidase activity of the intact protein, whereas the MPO inhibitory function of CP is abrogated. Analysis of the synovial fluid of 24 RA patients reveals that CP is proteolytically degraded to a variable extent, with a fragmentation pattern similar to that observed with thrombin in vitro, and that proteolysis is blocked by hirudin, a highly potent and specific thrombin inhibitor. Using independent biophysical techniques, we show that thrombin has intrinsic affinity for CP (Kd=60-270nM), independent of proteolysis, and inhibits CP ferroxidase activity (KI=22020nM). Mapping of thrombin binding sites with specific exosite-directed ligands (i.e., hirugen, fibrinogen ?'-peptide) and thrombin analogues having the exosites variably compromised (i.e., prothrombin, prethrombin-2, ?T-thrombin) reveals that the positively charged exosite-II of thrombin binds to the negatively charged upper region of CP, while the protease active site and exosite-I remain accessible. These results suggest that thrombin can exacerbate inflammation in RA by impairing the MPO inhibitory function of CP via proteolysis and by competitively inhibiting CP ferroxidase activity. Notably, local administration of hirudin, a highly potent and specifc thrombin inhibitor, reduces the concentration of active MPO in the synovial fluid of RA patients and has a beneficial effect on the clinical symptoms of the disease. PMID:26001728

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

    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.

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

    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

    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.

  6. Structure of Activated Thrombin-Activatable Fibrinolysis Inhibitor, a Molecular Link between Coagulation and Fibrinolysis

    Sanglas, Laura; Valnickova, Zuzana; Arolas, Joan L.; Pallarés, Irantzu; Guevara, Tibisay; Solà, Maria; Kristensen, Torsten Nygaard; Enghild, Jan J.; Avilés, Francesc X.; Gomis-Rüth, F. Xavier

    2008-01-01

    Thrombin-activatable fibrinolysis inhibitor (TAFI) is a metallocarboxypeptidase (MCP) that links blood coagulation and fibrinolysis. TAFI hampers fibrin-clot lysis and is a pharmacological target for the treatment of thrombotic conditions. TAFI is transformed through removal of its prodomain by thrombin-thrombomodulin into TAFIa, which is intrinsically unstable and has a short half-life in vivo. Here we show that purified bovine TAFI activated in the presence of a proteinaceous inhibitor rend...

  7. Identification and Mechanistic Analysis of a Novel Tick-Derived Inhibitor of Thrombin

    Jablonka, Willy; Kotsyfakis, Michalis; Mizurini, Daniella M.; Monteiro, Robson Q.; Lukszo, Jan; Drake, Steven K.; RIBEIRO, JOSÉ M. C.; Andersen, John F.

    2015-01-01

    A group of peptides from the salivary gland of the tick Hyalomma marginatum rufipes, a vector of Crimean Congo hemorrhagic fever show weak similarity to the madanins, a group of thrombin-inhibitory peptides from a second tick species, Haemaphysalis longicornis. We have evaluated the anti-serine protease activity of one of these H. marginatum peptides that has been given the name hyalomin-1. Hyalomin-1 was found to be a selective inhibitor of thrombin, blocking coagulation of plasma and inhibi...

  8. Induction of KDR expression in bovine arterial endothelial cells by thrombin: involvement of nitric oxide.

    Wang, Jie; Morita, Ikuo; Onodera, Mitsue; Murota, Sei-Itsu

    2002-02-01

    Thrombin, a multifunctional serine protease, is generated at the site with vascular injuries. It not only participates in the coagulation cascade, but also can induce a lot of events related to cell mitogenesis and migration. In this study, we investigated the effect of thrombin on endothelial cell proliferation induced by vascular endothelial growth factor (VEGF). Thrombin promoted proliferation of cultured bovine carotid endothelial cells in a time- and dose-dependent manner. Moreover, it drastically enhanced the cell growth stimulated by VEGF. This stimulatory effect was reduced by inhibitors of either protein kinase C (PKC) or mitogen-activated protein kinase kinase (MAPKK). Thrombin induced a significant increase in the level of mRNA of the kinase domain-containing receptor (KDR), but not tms-like tyrosine kinase (Flt-1), in a time-dependent manner, which reached the maximum after 24 h of stimulation. This increase coincides well with the KDR protein expression. The luciferase assay showed that thrombin induced an about 7.5-fold increase in the KDR promoter activity compared with the control. This enhanced KDR promoter activity was also abolished by inhibitors of either PKC or MAPKK. The deletion analyses indicated that the region between -115 and -97 (containing Sp1 binding region) within the KDR promoter gene was required for the enhanced KDR expression induced by thrombin and VEGF. Moreover, the nitric oxide synthase (NOS) inhibitor abolished both the accelerated cell proliferation and the increased KDR expression induced by thrombin and VEGF. This inhibition was abrogated by DETA NONOate, a NO donor with long half-life. These findings suggest that thrombin might potentiate the VEGF-induced angiogenic activity through increasing the level of the VEGF receptor KDR, in which production of NO is involved. PMID:11807828

  9. Rapid purification of high purity thrombin and preparation of a novel hemostat for clinical purposes

    Turaga, Krishna Kumar; Chakradhara Rao, P.; Sripad, G.

    2008-01-01

    Thrombin was prepared from crude prothrombin enriched plasma by activation using Russell’s viper venom. Prothrombin was prepared by barium sulphate adsorption and elution of prothrombin enriched fraction using high concentrations of sodium citrate. This fraction was directly activated with venom and thrombin was purified by SP Sepharose ion-exchange chromatography and subsequently over Phenyl-sepharose column. This product exhibits a purity of >98% with an activity of at least 6000U/mg or hig...

  10. Influence of Thrombin Concentration on the Mechanical and Morphological Properties of Cell-seeded Fibrin Hydrogels

    Rowe, Shaneen L.; Lee, SungYun; STEGEMANN, JAN P.

    2006-01-01

    Fibrin is a biopolymer that has been used in a variety of biomaterial, cell delivery and tissue engineering applications. The enzyme thrombin catalyzes the formation of fibrin microfibrils, which form a three-dimensional mesh in which cells can be directly embedded at the time of gel formation. In this study, fibrin hydrogels containing vascular smooth muscle cells were created using varying concentrations of thrombin. Over 7 days in culture, all gels decreased in volume as the fibrin matrix ...

  11. Thrombin-Activatable Fibrinolysis Inhibitor (TAFI) Deficient Mice Are Susceptible to Intracerebral Thrombosis and Ischemic Stroke

    Kraft, Peter; Schwarz, Tobias; Meijers, Joost C M; Stoll, Guido; Kleinschnitz, Christoph

    2012-01-01

    Background: Thrombus formation is a key step in the pathophysiology of acute ischemic stroke and results from the activation of the coagulation cascade. Thrombin plays a central role in this coagulation system and contributes to thrombus stability via activation of thrombin-activatable fibrinolysis inhibitor (TAFIa). TAFIa counteracts endogenous fibrinolysis at different stages and elevated TAFI levels are a risk factor for thrombotic events including ischemic stroke. Although substantial in ...

  12. Factor Xa and thrombin evoke additive calcium and proinflammatory responses in endothelial cells subjected to coagulation

    Daubie, Valéry; Cauwenberghs, Sandra; Senden, Nicole; Pochet, Roland; Lindhout, Théo; Buurman, Wim; Heemskerk, Johan

    2006-01-01

    Endothelial cells react to factor Xa and thrombin by proinflammatory responses. It is unclear how these cells respond under physiological conditions, where the serine proteases factor VIIa, factor Xa and thrombin are all simultaneously generated, as in tissue factor-driven blood coagulation. We studied the Ca2+ signaling and downstream release of interleukins (ILs), induced by these proteases in monolayers of human umbilical vein endothelial cells. In single cells, factor Xa, but not factor V...

  13. Leptospira interrogans reduces fibrin clot formation by modulating human thrombin activity via exosite I.

    Fernandes, Luis G; de Morais, Zenaide M; Vasconcellos, Silvio A; Nascimento, Ana L T O

    2015-06-01

    Pathogenic bacteria of the genus Leptospira are the etiological agents of leptospirosis, a disease that affects humans and animals worldwide. Although there are an increasing number of studies on the biology of Leptospira, the mechanisms of pathogenesis are not yet understood. We report in this work that Leptospira interrogans FIOCRUZ L1-130 virulent, M20 culture attenuated and the saprophyte L. biflexa Patoc 1 strains do not bind prothrombin. Leptospiral binding to thrombin was detected with the virulent, followed by culture-attenuated M20, and practically none was observed with the saprophyte strain. The interaction of Leptospira with thrombin mostly occurs via exosite I, with a minor participation of catalytic site, as determined by employing the thrombin inhibitors hirugen, hirudin and argatroban. Leptospira interrogans binding to thrombin inhibits its catalytic activity reducing fibrin clot formation in thrombin-catalyzed reaction of fibrinogen. This inhibition was more efficient with the virulent FIOCRUZ L1-130 than with the M20 culture attenuated, while none was seen with the saprophyte strain, suggesting that this binding might be important for bacterial virulence. This is the first study reporting the binding of pathogenic Leptospira to thrombin promoting a decrease in fibrin clotting that could lead to hemorrhage, helping bacteria dissemination. PMID:25834144

  14. Effect of bilineobin, a thrombin-like proteinase from the venom of common cantil (Agkistrodon bilineatus).

    Komori, Y; Nikai, T; Ohara, A; Yagihashi, S; Sugihara, H

    1993-03-01

    A thrombin-like proteinase, named bilineobin, was isolated from Agkistrodon bilineatus venom by Sephadex G-75, DEAE-Sephacel and Heparin-Sepharose CL-6B column chromatography. The purified enzyme has a mol. wt of 57,000 and catalysed the hydrolysis of arginine esters and thrombin substrates Boc-Val-Pro-Arg-MCA and Boc-Asp(OBz)-Pro-Arg-MCA. Although bilineobin converted fibrinogen into fibrin resulting in the production of fibrinopeptides, the activity was relatively low (0.65 NIH units/mg). Fibrinopeptides released upon hydrolysis by this proteinase were identified as fibrinopeptide A (FpA) and fibrinopeptide B (FpB) by measuring fast atom bombardment (FAB) mass spectra and amino acid sequence. This indicates that bilineobin hydrolyses the Arg(19)-Gly(20) bond in the A alpha chain and the Arg(21)-Gly(22) bond in the B beta chain of the bovine fibrinogen molecule. Kinetic study of FpA and FpB release reveals that bilineobin has a preference for cleaving the B beta chain. In addition, bilineobin is resistant to thrombin inhibitors such as hirudin. These suggest that the mechanism of action of bilineobin is similar but not identical to that of thrombin. It was demonstrated that the NH2-terminal region of bilineobin has significant similarities in sequence with thrombin-like proteinases from other snake venoms; however, only three residues were common with thrombin up to residue number 24. PMID:8470131

  15. Baicalin protects against thrombin induced cell injury in SH-SY5Y cells.

    Ju, Xiao-Ning; Mu, Wei-Na; Liu, Yuan-Tao; Wang, Mei-Hong; Kong, Feng; Sun, Chao; Zhou, Qing-Bo

    2015-01-01

    Baicalin, an extract from the dried root of Scutellaria baicalensis Georgi, was shown to be neuroprotective. However, the precise mechanisms are incompletely known. In this study, we determined the effect of baicalin on thrombin induced cell injury in SH-SY5Y cells, and explored the possible mechanisms. SH-SY5Y cells was treated with thrombin alone or pre-treated with baicalin (5, 10, 20 μM) for 2 h followed by thrombin treatment. Cells without thrombin and baicalin treatment were used as controls. Cell viability was detected by MTT assay. Cell apoptosis was analyzed by flow cytometry. Real-time PCR was performed to determine the mRNA expression of protease-activated receptor-1 (PAR-1). Western blotting was conducted to determine the protein expression of PAR-1, Caspase-3 and NF-κB. Baicalin reduced cell death following thrombin treatment in a dose-dependent manner, with concomitant inhibition of NF-κB activation and suppression of PAR-1 expression. In addition, baicalin reduced Caspase-3 expression. The above findings indicated that baicalin prevents against cell injury after thrombin stimulation possibly through inhibition of PAR-1 expression and NF-κB activation. PMID:26823714

  16. Identification of a thrombin sequence with growth factor activity on macrophages

    In contrast to fibroblasts, the exposure of G0/G1-arrested J774 cells, a murine macrophage-like tumor cell line, with either active or esterolytically inactive diisopropyl phosphorofluoridate-conjugated α-thrombin results in a mitogenic response as measured by increased [3H]thymidine incorporation. This response to thrombin is optimal at 10 nM and is specifically blocked by hirudin, a high-affinity thrombin inhibitor. When prethrombin 1 is cleaved with cyanogen bromide, a fragment (peptide CB67-129) is produced that, like the parent thrombin molecule, is mitogenic for J774 cells but not for fibroblasts. Limited tryptic digests of this fragment retain the ability to stimulate macrophages - a function that can be mimicked by a synthetic tetradecapeptide homologue of CB67-129 but not by any of a series of well-known growth promoters. The mitogenic effects of this peptide are not limited to J774 cells but can be expressed in other macrophage-like tumor cells lines. In addition to increased [3H]thymidine incorporation, the synthetic B chain peptide stimulates cell proliferation as evidenced by a dose-dependent increase in total protein per culture well and cell number. The authors conclude that the thrombin molecule contains a macrophage growth factor domain that is separate and distinct from its active center. Thus, thrombin, in addition to its major role in hemostasis and thrombosis, may also have important functions in such basic processes as the inflammatory response and monocytopoiesis

  17. Identification of a thrombin sequence with growth factor activity on macrophages

    Bar-Shavit, R.; Kahn, A.J.; Mann, K.G.; Wilner, G.D.

    1986-02-01

    In contrast to fibroblasts, the exposure of G0/G1-arrested J774 cells, a murine macrophage-like tumor cell line, with either active or esterolytically inactive diisopropyl phosphorofluoridate-conjugated -thrombin results in a mitogenic response as measured by increased (TH)thymidine incorporation. This response to thrombin is optimal at 10 nM and is specifically blocked by hirudin, a high-affinity thrombin inhibitor. When prethrombin 1 is cleaved with cyanogen bromide, a fragment (peptide CB67-129) is produced that, like the parent thrombin molecule, is mitogenic for J774 cells but not for fibroblasts. Limited tryptic digests of this fragment retain the ability to stimulate macrophages - a function that can be mimicked by a synthetic tetradecapeptide homologue of CB67-129 but not by any of a series of well-known growth promoters. The mitogenic effects of this peptide are not limited to J774 cells but can be expressed in other macrophage-like tumor cells lines. In addition to increased (TH)thymidine incorporation, the synthetic B chain peptide stimulates cell proliferation as evidenced by a dose-dependent increase in total protein per culture well and cell number. The authors conclude that the thrombin molecule contains a macrophage growth factor domain that is separate and distinct from its active center. Thus, thrombin, in addition to its major role in hemostasis and thrombosis, may also have important functions in such basic processes as the inflammatory response and monocytopoiesis.

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

    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

  19. Targeting thrombin long-term after an acute coronary syndrome: Opportunities and challenges.

    De Caterina, Raffaele; Goto, Shinya

    2016-06-01

    Patients after an acute coronary syndrome (ACS) are at increased risk of recurrent thrombotic events, justifying the search for additional antithrombotic treatments. The pathophysiology of ACS involves arterial thrombus formation, in turn occurring because of a combination of platelet activation and fibrin formation, with thrombin playing a key role in both. Antiplatelet therapy, targeting the thromboxane pathway and the ADP P2Y12 receptor has been widely accepted for secondary prevention after an ACS. Now, data from recent clinical trials in such patients also encourage the pursuit of inhibiting thrombin formation or thrombin-mediated platelet activation in addition to antiplatelet therapy. This "triple pathway inhibition", including inhibition of thrombin activity or thrombin receptor(s), is currently an option in pure ACS, but already a must in the setting of ACS accompanied by atrial fibrillation (AF), where anticoagulants have been shown to be much more effective than antiplatelet agents in preventing stroke. We here discuss the challenges of managing combined thrombin activity or receptor inhibition and antiplatelet therapy in all such patients. Translating this into practice still requires further studies and patient tailoring to fully exploit its potential. PMID:26994821

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

    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

  1. Thrombin generation as a predictor of radiotherapy induced skin erythema

    Background and purpose: Biological mechanisms underlying radiation induced erythema remain largely unknown, with no simple way to accurately predict or prevent extreme cases. Based on the recent findings in patients suffering from chronic urticaria, we sought to determine if similar mechanisms of hypercoagulation contributed to comparable skin reactions during radiotherapy. Materials and methods: Plasma levels of prothrombin factor 1+2 (F1+2), D-dimers and plasminogen activator inhibitor-1 (Pai-1) were tested in 32 women undergoing irradiation following breast conserving surgery for early breast cancer. Reflectance spectrophotometry was used to objectively assess erythema throughout the treatment by measuring the amount of light reflected from the skin surface as a function of wavelength. Correlations between peak levels of erythema and plasma biomarkers were then assessed. Results: Individual peak reflectance readings generally occurred between day 29 of treatment and 2 weeks post radiotherapy, and represented a median increase of 66% (range: 11-146%; p < 0.001) from baseline. Peak reflectance correlated with F1+2 and Pai-1 levels measured both at baseline and day 29 of treatment, and multivariate analysis indicated that these two baseline measurements were the best predictors of peak reflectance, accounting for 59% of the variability in erythema (p = 0.000004). Conclusions: Patients with signs of intravascular thrombin generation are at higher risk of radiotherapy-induced skin reactions, providing a new therapeutic avenue for possibly predicting and preventing this side effect of cancer treatment

  2. How does association process affect fibrinogen hydrolysis by thrombin?

    Zavyalova, Elena; Kopylov, Alexey

    2014-12-01

    Thrombin, a key enzyme in the blood coagulation cascade, hydrolyzes fibrinogen into fibrin, which specifically associates into the fibers that build up a thrombus scaffold. The assembly of fibrin involves a set of stepwise reactions, for which a complete and detailed kinetic portrait is needed. Existing kinetic models focus on particular parts of the process, for example the mechanism of enzyme action itself or the kinetics of formation of fibrin assemblies. The current study considers a thorough model of the process from fibrinogen hydrolysis to the assembly of fibrin. Composing the model requires taking into account several reaction intermediates, stepwise removal of fibrinopeptides, and association of partially hydrolyzed fibrin, in particular desAA fibrin. The model is versatile enough to adopt new data both on fibrinogen hydrolysis and fibrin association. In addition, the model could be considered as an example of a kinetic description of other complex enzyme systems having several intermediates and feedbacks, such as the blood coagulation cascade and signal transduction. PMID:25239831

  3. The Expression of the Thrombin Receptors PAR-3 and PAR-4 is Downregulated in Pancreatic Cancer Cell Lines

    Claudia Rudroff; Annette Richard; Edmund AM Neugebauer; Sarah Hilswicht

    2015-01-01

    Background: Patients with pancreatic cancer frequently suffer from thrombosis as a consequence of excess thrombin generation. In addition to its role in the plasmatic coagulation cascade, thrombin induces numerous cellular effects by activating a unique group of G-protein-coupled receptors on the cell membrane, the proteinase-activated receptors (PARs). At present, PAR-1, PAR-3 and PAR-4 are known to be activated by thrombin. We previously demonstrated a putative role for PAR-1 in pancreatic ...

  4. Thrombin-induced neuronal protection: role of the mitogen activated protein kinase/ribosomal protein S6 kinase pathway

    Hu, Haitao; Yamashita, Shiro; Hua, Ya; Keep, Richard F.; Liu, Wenquan; Xi, Guohua

    2010-01-01

    Our previous studies have found that intracerebral pretreatment with a low dose of thrombin (thrombin preconditioning, TPC) reduces infarct volume and attenuates brain edema after focal cerebral ischemia. In this study, we examined whether TPC protects against the neuronal death induced by oxygen glucose deprivation (OGD), and whether the protection is through thrombin receptors and the p44/42 mitogen activated protein kinases (MAPK)/ribosomal protein S6 kinases (p70 S6K) pathway.

  5. Thrombin-induced p38 mitogen-activated protein kinase activation is mediated by epidermal growth factor receptor transactivation pathway

    Kanda, Yasunari; Mizuno, Katsushige; Kuroki, Yasutomi; Watanabe, Yasuhiro

    2001-01-01

    Thrombin is a potent mitogen for vascular smooth muscle cells (VSMC) and has been implicated its pathogenic role in vascular remodelling. However, the signalling pathways by which thrombin mediates its mitogenic response are not fully understood.We have previously reported that thrombin activates p38 mitogen-activated protein kinase (p38 MAPK) by a tyrosine kinase-dependent mechanism, and that p38 MAPK has a role in thrombin-induced mitogenic response in rat VSMC.In the present study, we exam...

  6. Construction of photoelectrochemical thrombin aptasensor via assembling multilayer of graphene-CdS nanocomposites.

    Shangguan, Li; Zhu, Wei; Xue, Yanchun; Liu, Songqin

    2015-02-15

    A photoelectrochemical (PEC) aptasensor for highly sensitive and specific detection of thrombin was developed by using graphene–CdS nanocomposites multilayer as photoactive species and electroactive mediator hexaammineruthenium(III) chloride (Ru(NH(3))(6)(3+)) as signal enhancer. Graphene–CdS nanocomposites (G–CdS) were synthesized by one-pot reduction of oxide graphene and CdCl2 with thioacetamide. The photoactive multilayer was prepared by alternative assembly of the negatively charged 3-mercaptopropionic acid modified graphene–CdS nanocomposites (MPA-G–CdS) and the positively charged polyethylenimine (PEI) on ITO electrode. This layer-by-layer assembly method enhanced the stability and homogeneity of the photocurrent readout of G–CdS. Thrombin aptamer was covalently bound to the multilayer by using glutaraldehyde as cross-linking. Electroactive mediator (Ru(NH(3))(6)(3+)) could interact with the DNA phosphate backbone and thus facilitated the electron transfer between G–CdS multilayer and electrode and enhanced the photocurrent. Hybridizing of a long complementary DNA with thrombin aptamer could increase the adsorption amount of (Ru(NH(3))(6)(3+)), which in turn boosted the signal readout. In the presence of target thrombin, the affinity interaction between thrombin and its aptamer resulted in the long complementary DNA releasing from the G–CdS multilayer and decreasing of photocurrent signal. On the basis of G–CdS multilayer as the photoactive species, (Ru (NH(3))(6)(3+)) as an electroactive mediator, and aptamer as a recognition module, a high sensitive PEC aptasensor for thrombin detection was proposed. The thrombin aptasensor displayed a linear range from 2.0 pM to 600.0 pM and a detection limit of 1.0 pM. The present strategy provided a promising ideology for the future development of PEC biosensor. PMID:25314620

  7. Percutaneous treatment of femoral pseudoaneurysms: comparison of fibrin sealant against thrombin

    Daniel Mendes Pinto

    2013-12-01

    Full Text Available INTRODUCTION: Femoral pseudoaneurysms are a complication that occurs in connection with up to 8% of percutaneous procedures. Of the available treatments, ultrasound guided thrombin injection has a high success rate and is well-tolerated by patients. The combination of thrombin and fibrinogen known as fibrin sealant forms a stable clot and can be used to treat pseudoaneurysms, particularly those with complex anatomy and larger size. OBJECTIVE: To compare the results of treating femoral pseudoaneurysm in two ways: Group T was treated with thrombin alone and Group T+F was treated with fibrin sealant (thrombin+fibrinogen. METHODS: A retrospective analysis was conducted of femoral pseudoaneurysm cases treated between January 2005 and December 2012. RESULTS: Twenty-eight patients were treated, 21 with thrombin alone and seven with fibrin sealant. All patients in group T were treated successfully, but only four patients in group T+F were treated successfully (57.1% success rate in Group T+F, p<0.01. The three cases of failure in group T+F needed surgery and in one of these cases the complication was embolization to the femoral bifurcation. The pseudoaneurysms that were treated with fibrin sealant were larger (25 cm3 in Group T and 57.7 cm3 in Group T+F, p=0.02 and required larger volumes of thrombin (0.5 mL in Group T and 1.0 mL in Group T+F, p<0.01. There was one complication in Group T and two complications in Group T+F (p<0.01. CONCLUSIONS: Irrespective of the small number of cases reviewed, treatment with thrombin alone was superior to treating with fibrin sealant, since it caused few complications and was more effective at correcting pseudoaneurysms.

  8. Expression and partial biochemical characterization of a recombinant serine protease from Bothrops pauloensis snake venom.

    Isabel, Thais F; Costa, Guilherme Nunes Moreira; Pacheco, Isabela B; Barbosa, Luana G; Santos-Junior, Célio D; Fonseca, Fernando P P; Boldrini França, Johara; Henrique-Silva, Flávio; Yoneyama, Kelly A G; Rodrigues, Renata S; Rodrigues, Veridiana de Melo

    2016-06-01

    Snake venom serine proteases (SVSPs) are enzymes capable of interfering at several points of hemostasis. Some serine proteases present thrombin-like activity, which makes them targets for the development of therapeutics agents in the treatment of many hemostatic disorders. In this study, a recombinant thrombin-like serine protease, denominated rBpSP-II, was obtained from cDNA of the Bothrops pauloensis venom gland and was characterized enzymatically and biochemically. The enzyme rBpSP-II showed clotting activity on bovine plasma and proteolytic activity on fibrinogen, cleaving exclusively the Aα chain. The evaluation of rBpSP-II activity on chromogenic substrates demonstrated thrombin-like activity of the enzyme due to its capacity to hydrolyze the thrombin substrate. These characteristics make rBpSP-II an attractive molecule for additional studies. Further research is needed to verify whether rBpSP-II can serve as a template for the synthesis of therapeutic agents to treat hemostatic disorders. PMID:26965926

  9. The effect of resveratrol on the platelet secretory process induced by endotoxin and thrombin.

    Olas, B; Wachowicz, B; Szewczuk, J; Saluk-Juszczak, J; Kaca, W

    2001-01-01

    The effect of resveratrol (trans-3,4',5-trihydroxystilbene) on the release of adenine nucleotides and proteins from blood platelets activated by lipopolysaccharide (LPS), from Proteus mirabilis and by thrombin, were studied. Thrombin stimulated the release of adenine nucleotides from dense granules and proteins from alpha-granules. The LPS (0.3 microg/10(8) platelets, 5 min, 37 degrees C), like thrombin (2.5 U/10(8) platelets, 5 min, 37 degrees C) was found to cause a release of adenine nucleotides and proteins (p <0.05). Resveratrol (6.25-100 microg/ml, 30 min, 37 degrees C) had a different effect on the platelet release reaction caused by either LPS or thrombin. The results indicated that resveratrol inhibited, in dose-dependent manner, the secretory process (release of adenine nucleotides and proteins) induced by thrombin (p <0.05), but it significantly stimulated the liberation of proteins from blood platelets activated by LPS (p <0.05). PMID:11368092

  10. Gold nanocluster-encapsulated glucoamylase as a biolabel for sensitive detection of thrombin with glucometer readout

    This article reports on a sensitive aptamer-based assay for thrombin. The assay includes the following steps: (a) a first thrombin-specific aptamer (P1) was immobilized on the surface of the wells of a microtiter plate via biotin-streptavidin interaction; (b) gold nanoclusters (GNCs) were used to cover the enzyme glucoamylase via a reverse micelle method; (c) the GNCs were then coated with the second aptamer (P2) via thiol chemistry; (d) addition of a solution containing thrombin to the well, and (e) subsequent addition of amylopectin. The glucoamylase in the GNC label catalytically hydrolyzes the amylopectin to form glucose which then is quantified with a glucometer. Under optimal conditions, the signal for glucose increases with the concentration of thrombin in range from 0.05 to 100 nM, and the detection limit is as low as 10 pM. The assay has a good repeatability and displays an intermediate precision of down to 11 %. Nonspecific adsorption was not observed in a series of analyses. The method was applied to the determination of thrombin in spiked serum samples, and the recoveries ranged from 94 to 110 %. The method is assumed to have a wide scope in that it may be extended to numerous other analytes for which appropriate aptamers are available. (author)

  11. Three different signal amplification strategies for the impedimetric sandwich detection of thrombin.

    Ocaa, Cristina; Del Valle, Manel

    2016-03-17

    In this work, we report a comparative study on three highly specific amplification strategies for the ultrasensitive detection of thrombin with the use of aptamer sandwich protocol. The protocol consisted on the use of a first thrombin aptamer immobilized on the electrode surface, the recognition of thrombin protein, and the reaction with a second biotinylated thrombin aptamer forming the sandwich. Through the exposed biotin end, three variants have been tested to amplify the electrochemical impedance signal. The strategies included (a) silver enhancement treatment, (b) gold enhancement treatment and (c) insoluble product produced by the combination of the enzyme horseradish peroxidase (HRP) and 3-amino-9-ethylcarbazole (AEC). The properties of the sensing surface were probed by electrochemical impedance measurements in the presence of the ferrocyanide/ferricyanide redox marker. Insoluble product strategy and silver enhancement treatment resulted in the lowest detection limit (0.3pM), while gold enhancement method resulted in the highest reproducibility, 8.8% RSD at the pM thrombin concentration levels. Results of silver and gold enhancement treatment also permitted direct inspection by scanning electron microscopy (SEM). PMID:26920780

  12. Genetic Determinants of Thrombin Generation and Their Relation to Venous Thrombosis: Results from the GAIT-2 Project

    Martin-Fernandez, Laura; Ziyatdinov, Andrey; Carrasco, Marina; Millon, Juan Antonio; Martinez-Perez, Angel; Vilalta, Noelia; Brunel, Helena; Font, Montserrat; Hamsten, Anders; Souto, Juan Carlos; Soria, Jos Manuel

    2016-01-01

    Background Venous thromboembolism (VTE) is a common disease where known genetic risk factors explain only a small portion of the genetic variance. Then, the analysis of intermediate phenotypes, such as thrombin generation assay, can be used to identify novel genetic risk factors that contribute to VTE. Objectives To investigate the genetic basis of distinct quantitative phenotypes of thrombin generation and its relationship to the risk of VTE. Patients/Methods Lag time, thrombin peak and endogenous thrombin potential (ETP) were measured in the families of the Genetic Analysis of Idiopathic Thrombophilia 2 (GAIT-2) Project. This sample consisted of 935 individuals in 35 extended families selected through a proband with idiopathic thrombophilia. We performed also genome wide association studies (GWAS) with thrombin generation phenotypes. Results The results showed that 67% of the variation in the risk of VTE is attributable to genetic factors. The heritabilities of lag time, thrombin peak and ETP were 49%, 54% and 52%, respectively. More importantly, we demonstrated also the existence of positive genetic correlations between thrombin peak or ETP and the risk of VTE. Moreover, the major genetic determinant of thrombin generation was the F2 gene. However, other suggestive signals were observed. Conclusions The thrombin generation phenotypes are strongly genetically determined. The thrombin peak and ETP are significantly genetically correlated with the risk of VTE. In addition, F2 was identified as a major determinant of thrombin generation. We reported suggestive signals that might increase our knowledge to explain the variability of this important phenotype. Validation and functional studies are required to confirm GWAS results. PMID:26784699

  13. Topical report review status

    NONE

    1997-08-01

    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.

  14. Topical report review status

    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

  15. A Universal Base in a Specific Role: Tuning up a Thrombin Aptamer with 5-Nitroindole

    Tsvetkov, Vladimir B.; Varizhuk, Anna M.; Pozmogova, Galina E.; Smirnov, Igor P.; Kolganova, Natalia A.; Timofeev, Edward N.

    2015-11-01

    In this study we describe new modified analogs of the thrombin binding aptamer (TBA) containing 5-nitroindole residues. It has been shown that all modified TBAs form an anti-parallel G-quadruplex structure and retain the ability to inhibit thrombin. The most advanced TBA variant (TBA-N8) has a substantially increased clotting time and two-fold lower IC50 value compared to the unmodified prototype. Molecular modelling studies suggest that the improved anticoagulant properties of TBA-N8 result from changes in the binding mode of the analog. A modified central loop in TBA-N8 is presumed to participate in the binding of the target protein. Studies of FAM labelled TBA and TBA-N8 showed an improved binding affinity of the modified aptamer and provided evidence of a direct interaction between the modified central loop and thrombin. Our findings have implications for the design of new aptamers with improved binding affinities.

  16. The Effect of Vitamin D Supplementation on Thrombin Generation Assessed by the Calibrated Automated Thrombogram.

    Saliba, Walid; Awad, Karem; Ron, Gilat; Elias, Mazen

    2016-05-01

    Observational and in vitro studies suggest that vitamin D may have antithrombotic activity. This study aimed to examine the relationship between vitamin D supplementation and thrombin generation. Serum 25-hydroxyvitamin D (25(OH)D) and thrombin generation parameters were measured in 73 healthy volunteers. Participants with serum 25(OH)D vitamin D3and tested for 25(OH)D and thrombin generation at the end of treatment. Lag time and time to peak decreased after treatment by a mean of -0.49 ± 0.51 minute (Pvitamin D supplementation seems to have prothrombotic effect in patients with vitamin D insufficiency. These findings should be interpreted with caution and need to be replicated in future studies. PMID:25376616

  17. Salmon-derived thrombin inhibits development of chronic pain through an endothelial barrier protective mechanism dependent on APC.

    Smith, Jenell R; Galie, Peter A; Slochower, David R; Weisshaar, Christine L; Janmey, Paul A; Winkelstein, Beth A

    2016-02-01

    Many neurological disorders are initiated by blood-brain barrier breakdown, which potentiates spinal neuroinflammation and neurodegeneration. Peripheral neuropathic injuries are known to disrupt the blood-spinal cord barrier (BSCB) and to potentiate inflammation. But, it is not known whether BSCB breakdown facilitates pain development. In this study, a neural compression model in the rat was used to evaluate relationships among BSCB permeability, inflammation and pain-related behaviors. BSCB permeability increases transiently only after injury that induces mechanical hyperalgesia, which correlates with serum concentrations of pro-inflammatory cytokines, IL-7, IL-12, IL-1? and TNF-?. Mammalian thrombin dually regulates vascular permeability through PAR1 and activated protein C (APC). Since thrombin protects vascular integrity through APC, directing its affinity towards protein C, while still promoting coagulation, might be an ideal treatment for BSCB-disrupting disorders. Salmon thrombin, which prevents the development of mechanical allodynia, also prevents BSCB breakdown after neural injury and actively inhibits TNF-?-induced endothelial permeability invitro, which is not evident the case for human thrombin. Salmon thrombin's production of APC faster than human thrombin is confirmed using a fluorogenic assay and APC is shown to inhibit BSCB breakdown and pain-related behaviors similar to salmon thrombin. Together, these studies highlight the impact of BSCB on pain and establish salmon thrombin as an effective blocker of BSCB, and resulting nociception, through its preferential affinity for protein C. PMID:26708087

  18. Positive cooperativity between the thrombin and bradykinin B2 receptors enhances arachidonic acid release.

    Hecquet, Claudie; Biyashev, Dauren; Tan, Fulong; Erdös, Ervin G

    2006-03-01

    Bradykinin (BK) or kallikreins activate B2 receptors (R) that couple Galpha(i) and Galpha(q) proteins to release arachidonic acid (AA) and elevate intracellular Ca2+ concentration ([Ca2+]i). Thrombin cleaves the protease-activated-receptor-1 (PAR1) that couples Galpha(i), Galpha(q), and Galpha(12/13) proteins. In Chinese hamster ovary cells stably transfected with human B2R, thrombin liberated little AA, but it significantly potentiated AA release by B2R agonists. We explored mechanisms of cooperativity between constitutively expressed PAR1 and B2R. We also examined human endothelial cells expressing both Rs constitutively. The PAR1 agonist hexapeptide (TRAP) was as effective as thrombin. Inhibitors of components of Galpha(i), Galpha(q), and Galpha(12/13) signaling pathways, and a protein kinase C (PKC)-alpha inhibitor, Gö-6976, blocked potentiation, while phorbol, an activator, enhanced it. Several inhibitors, including a RhoA kinase inhibitor, a [Ca2+]i antagonist, and an inositol-(1,3,4)-trisphosphate R antagonist, reduced mobilization of [Ca2+]i by thrombin and blocked potentiation of AA release by B2R agonists. Because either a nonselective inhibitor (isotetrandrine) of phospholipase A2 (PLA2) or a Ca2+-dependent PLA2 inhibitor abolished potentiation of AA release by thrombin, while a Ca2+-independent PLA2 inhibitor did not, we concluded that the mechanism involves Ca2+-dependent PLA2 activation. Both thrombin and TRAP modified activation and phosphorylation of the B2R induced by BK. In lower concentrations they enhanced it, while higher concentrations inhibited phosphorylation and diminished B2R activation. Protection of the NH2-terminal Ser1-Phe2 bond of TRAP by an aminopeptidase inhibitor made this peptide much more active than the unprotected agonist. Thus PAR1 activation enhances AA release by B2R agonists through signal transduction pathway. PMID:16183725

  19. Positive cooperativity between the thrombin and bradykinin B2 receptors enhances arachidonic acid release

    Hecquet, Claudie; Biyashev, Dauren; Tan, Fulong; Erdös, Ervin G.

    2006-01-01

    Bradykinin (BK) or kallikreins activate B2 receptors (R) which couple Gαi and Gαq proteins to release arachidonic acid (AA) and elevate [Ca2+]i. Thrombin cleaves the protease-activated-receptor-1 (PAR1) that couples Gαi, Gαq and Gα12/13 proteins. In CHO cells stably transfected with human B2R, thrombin liberated little AA, but it significantly potentiated AA release by B2R agonists. We explored mechanisms of cooperativity between constitutively expressed PAR1 and B2R. We also examined human endothelial cells expressing both Rs constitutively. The PAR1 agonist hexapeptide (TRAP) was as effective as thrombin. Inhibitors of components of Gαi, Gαq and Gα12/13 signaling pathways, and a PKCα inhibitor, Gö6976 blocked potentiation while phorbol, an activator, enhanced it. Several inhibitors, including a RhoA kinase inhibitor, a [Ca2+]i antagonist, and an inositol-(1,3,4)-trisphosphate R antagonist, reduced mobilization of [Ca2+]i by thrombin and blocked potentiation of AA release by B2R agonists. Because either a non-selective inhibitor (isotetrandrine) of phospholipase A2 (PLA2) or a Ca2+-dependent PLA2 inhibitor abolished potentiation of AA release by thrombin, while a Ca2+-independent PLA2 inhibitor did not, we concluded that the mechanism involves Ca2+-dependent PLA2 activation. Both thrombin and TRAP modified activation and phosphorylation of the B2R induced by BK. In lower concentrations they enhanced it, while higher concentrations inhibited phosphorylation and diminished B2R activation. Protection of the N-terminal Ser1-Phe2 bond of TRAP by an aminopeptidase inhibitor made this peptide much more active than the unprotected agonist. Thus, PAR1 activation enhances AA release by B2R agonists through signal transduction pathway. PMID:16183725

  20. Evaluation of antithrombotic activity of thrombin DNA aptamers by a murine thrombosis model.

    Zavyalova, Elena; Samoylenkova, Nadezhda; Revishchin, Alexander; Golovin, Andrey; Pavlova, Galina; Kopylov, Alexey

    2014-01-01

    Aptamers are nucleic acid based molecular recognition elements with a high potential for the theranostics. Some of the aptamers are under development for therapeutic applications as promising antithrombotic agents; and G-quadruplex DNA aptamers, which directly inhibit the thrombin activity, are among them. RA-36, the 31-meric DNA aptamer, consists of two thrombin binding pharmacophores joined with the thymine linker. It has been shown earlier that RA-36 directly inhibits thrombin in the reaction of fibrinogen hydrolysis, and also it inhibits plasma and blood coagulation. Studies of both inhibitory and anticoagulation effects had indicated rather high species specificity of the aptamer. Further R&D of RA-36 requires exploring its efficiency in vivo. Therefore the development of a robust and adequate animal model for effective physiological studies of aptamers is in high current demand. This work is devoted to in vivo study of the antithrombotic effect of RA-36 aptamer. A murine model of thrombosis has been applied to reveal a lag and even prevention of thrombus formation when RA-36 was intravenous bolus injected in high doses of 1.4-7.1 mol/kg (14-70 mg/kg). A comparative study of RA-36 aptamer and bivalirudin reveals that both direct thrombin inhibitors have similar antithrombotic effects for the murine model of thrombosis; though in vitro bivalirudin has anticoagulation activity several times higher compared to RA-36. The results indicate that both RA-36 aptamer and bivalirudin are direct thrombin inhibitors of different potency, but possible interactions of the thrombin-inhibitor complex with other components of blood coagulation cascade level the physiological effects for both inhibitors. PMID:25192011

  1. Real-time detection of ?-thrombin binding to single-strand DNA aptamers by a highly sensitive Si-based waveguide SPR biosensor

    Huang, Chi-Chieh; Hsu, Hsin-Feng; Chen, Sz-Hau; Tsai, Kun-Yu; Huang, Yang-Tung; Lin, Chih-Sheng; Hsu, Shih-Hsin

    2012-02-01

    ?In this paper, real-time characterization of ?-thrombin binding to single-strand DNA (ssDNA) aptamers by novel Si-based waveguide SPR biosensors has been investigated. The gold nanoparticles (AuNPs) modified with anti-thrombin antibodies were employed to bind with ?-thrombin via strong antibody/antigen affinity for SPR signal amplification. The detection limit of 1 pM for -thrombin detection was achieved.

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

    Marjanovi? Marjan

    2002-01-01

    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.

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

    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

  4. Biochemical characterization of bovine plasma thrombin-activatable fibrinolysis inhibitor (TAFI)

    Valnickova, Zuzana; Thaysen-Andersen, Morten; Hjrup, Peter; Christensen, Trine; Sanggaard, Kristian W; Kristensen, Torsten; Enghild, Jan J

    2009-01-01

    BACKGROUND: TAFI is a plasma protein assumed to be an important link between coagulation and fibrinolysis. The three-dimensional crystal structures of authentic mature bovine TAFI (TAFIa) in complex with tick carboxypeptidase inhibitor, authentic full lenght bovine plasma thrombin-activatable fib......BACKGROUND: TAFI is a plasma protein assumed to be an important link between coagulation and fibrinolysis. The three-dimensional crystal structures of authentic mature bovine TAFI (TAFIa) in complex with tick carboxypeptidase inhibitor, authentic full lenght bovine plasma thrombin...

  5. Computer based screening of compound databases: 1. Preselection of benzamidine-based thrombin inhibitors.

    Fox, T; Haaksma, E E

    2000-07-01

    We present a computational protocol which uses the known three-dimensional structure of a target enzyme to identify possible ligands from databases of compounds with low molecular weight. This is accomplished by first mapping the essential interactions in the binding site with the program GRID. The resulting regions of favorable interaction between target and ligand are translated into a database query, and with UNITY a flexible 3D database search is performed. The feasibility of this approach is calibrated with thrombin as the target. Our results show that the resulting hit lists are enriched with thrombin inhibitors compared to the total database. PMID:10896314

  6. Positive cooperativity between the thrombin and bradykinin B2 receptors enhances arachidonic acid release

    Hecquet, Claudie; Biyashev, Dauren; Tan, Fulong; Erdös, Ervin G.

    2005-01-01

    Bradykinin (BK) or kallikreins activate B2 receptors (R) which couple Gαi and Gαq proteins to release arachidonic acid (AA) and elevate [Ca2+]i. Thrombin cleaves the protease-activated-receptor-1 (PAR1) that couples Gαi, Gαq and Gα12/13 proteins. In CHO cells stably transfected with human B2R, thrombin liberated little AA, but it significantly potentiated AA release by B2R agonists. We explored mechanisms of cooperativity between constitutively expressed PAR1 and B2R. We also examined human e...

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

    Tobin, W O

    2013-02-01

    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.

  8. Freshman Health Topics

    Hovde, Karen

    2011-01-01

    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.…

  9. Freshman Health Topics

    Hovde, Karen

    2011-01-01

    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.

  10. Health Topic XML File Description

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

  11. Syntactic Topic Models

    Boyd-Graber, Jordan

    2010-01-01

    The syntactic topic model (STM) is a Bayesian nonparametric model of language that discovers latent distributions of words (topics) that are both semantically and syntactically coherent. The STM models dependency parsed corpora where sentences are grouped into documents. It assumes that each word is drawn from a latent topic chosen by combining document-level features and the local syntactic context. Each document has a distribution over latent topics, as in topic models, which provides the semantic consistency. Each element in the dependency parse tree also has a distribution over the topics of its children, as in latent-state syntax models, which provides the syntactic consistency. These distributions are convolved so that the topic of each word is likely under both its document and syntactic context. We derive a fast posterior inference algorithm based on variational methods. We report qualitative and quantitative studies on both synthetic data and hand-parsed documents. We show that the STM is a more pred...

  12. Thrombin detection in murine plasma using engineered fluorescence resonance energy transfer aptadimers

    Trapaidze, Ana; Brut, Marie; Mazères, Serge; Estève, Daniel; Gué, Anne-Marie; Bancaud, Aurélien

    2015-12-01

    Biodetection strategies, in which two sides of one target protein are targeted simultaneously, have been shown to increase specificity, selectivity, and affinity, and it has been suggested that they constitute excellent candidates for protein sensing in complex media. In this study we propose a method to engineer the sequence of a DNA construct dedicated to reversible thrombin detection. This construct, called Fluorescence Resonance Energy Transfer (FRET) aptadimer, is assembled with two aptamers, which target different epitopes of thrombin, interconnected with a DNA linker that contains a FRET couple and a reversible double helix stem. In the absence of target, the stem is stable maintaining a FRET couple in close proximity, and fluorescence is unquenched upon thrombin addition due to the dehybridization of the stem. We define design rules for the conception of FRET aptadimers, and develop a software to optimize their functionality. One engineered FRET aptadimer sequence is subsequently characterized experimentally by temperature scanning fluorimetry, demonstrating the relevance of our technology for thrombin sensing in bulk and diluted murine plasma.

  13. Thrombin-activatable fibrinolysis inhibitor activity in healthy and diseased dogs

    Jessen, Lisbeth Rem; Wiinberg, Bo; Kjelgaard-Hansen, Mads; Jensen, Asger Lundorff; Rozanski, Elizabeth; Kristensen, Annemarie Thuri

    2010-01-01

    Background: In people, increased thrombin-activatable fibrinolysis inhibitor (TAFI) antigen has been associated with increased risk of thrombosis, and decreased TAFI may contribute to bleeding diathesis. TAFI activity in dogs has been described in experimental models, but not in dogs with spontan...

  14. Microfluidic chip-based silver nanoparticles aptasensor for colorimetric detection of thrombin.

    Zhao, Yaju; Liu, Xiaohui; Li, Jie; Qiang, Weibing; Sun, Liang; Li, Hui; Xu, Danke

    2016-04-01

    In this paper, a colorimetric silver nanoparticles aptasensor (aptamer-AgNPs) was developed for simple and straightforward detection of protein in microfluidic chip. Surface-functionalized microfluidic channels were employed as the capture platform. Then the mixture of target protein and aptamer-AgNPs were injected into the microfluidic channels for colorimetric detection. To demonstrate the performance of this detection platform, thrombin was chosen as a model target protein. Introduction of thrombin could form a sandwich-type complex involving immobilized AgNPs. The amount of aptamer-AgNPs on the complex augmented along with the increase of the thrombin concentration causing different color change that can be analyzed both by naked eyes and a flatbed scanner. This method is featured with low sample consumption, simple processes of microfluidic platform and straightforward colorimetric detection with aptamer-AgNPs. Thrombin at concentrations as low as 20pM can be detected using this aptasensor without signal amplification. This work demonstrated that it had good selectivity over other proteins and it could be a useful strategy to detect other targets with two affinity binding sites for ligands as well. PMID:26838384

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

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

    2012-12-01

    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 α-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/μL, and the thrombin binding capacity was 1.15 μg/μL, 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

  16. A study of the conditions and accuracy of the thrombin time assay of plasma fibrinogen

    Jespersen, J; Sidelmann, Johannes Jakobsen

    1982-01-01

    The conditions, accuracy, precision and possible error of the thrombin time assay of plasma fibrinogen are determined. Comparison with an estimation of clottable protein by absorbance at 280 nm gave a correlation coefficient of 0.96 and the regression line y = 1.00 x + 0.56 (n = 34). Comparison...

  17. Early thrombin generation and impaired fibrinolysis after SCT associate with acute GVHD.

    Pinomki, A; Volin, L; Joutsi-Korhonen, L; Virtanen, J O; Lemponen, M; Ruutu, T; Lassila, R

    2010-04-01

    The evolution of coagulation and fibrinolysis has not been thoroughly evaluated in allogeneic SCT. In this pilot study, we characterized the adaptive mechanisms of coagulation and fibrinolysis during allogeneic SCT and 3-month follow-up and studied possible associations with outcome, including acute GVHD. Thirty patients underwent SCT for a haematological malignancy after myeloablative conditioning. Nineteen patients received the transplant from an HLA-identical sibling and 11 from an unrelated donor. GVHD prophylaxis consisted of CYA and MTX, with methylprednisolone in sibling transplants. Serial coagulation and fibrinolytic activity markers were assessed, including prothrombin fragments 1+2 (F1+2), thrombin time, D-dimer, tissue-type plasminogen-activator (tPA) and plasminogen-activator inhibitor (PAI-1). Early during conditioning therapy, F1+2 and D-dimer increased threefold indicating thrombin generation and fibrin turnover. TPA activity peaked before engraftment, concurring with diminished PAI-1. At 10 days after transplantation shortened thrombin time (<15 s), F1+2 exceeding 0.7 nmol/L and PAI-1 3.0 IU/mL were associated with the development of GVHD. In conclusion, early maladaptation, that is, upregulated thrombin generation and inhibition of fibrinolysis, occurred in one-third of the SCT patients associating with the development of GVHD, a finding suggesting an interplay between coagulation and immunology during SCT. PMID:19718071

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

    Rosenfeldt Hans

    2006-12-01

    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.

  19. Reversible regulation of thrombin adsorption and desorption based on photoresponsive-aptamer modified gold nanoparticles.

    Yu, Jiemiao; Yang, Liangrong; Liang, Xiangfeng; Dong, Tingting; Liu, Huizhou

    2015-11-01

    In the protein separation, adsorption and desorption of target protein have been using different buffer condition. Different buffer will change the structure and activity of target protein in some cases. This work describes the use of different wavelength light for remote regulation of adsorption and desorption of target protein in the same buffer solutions. A dynamic system that captured and released protein in response to light is reported. Matrix gold nanoparticles and light-responsive affinity ligand comprising thrombin aptamer (APT15), polyethylene glycol linker, and azobenzene-modified complementary sequence were used. UV light induced a trans-cis isomerization of the azobenzene that destabilized the duplex of aptamer and azobenzene-modified complementary sequence, resulting in thrombin binding to aptamer sequence. Visible light irradiation resulted in DNA duplex rehybridization and thrombin released. Our work demonstrates that different light wavelengths effectively regulated the adsorption and desorption of thrombin in the same buffer, and this system also can capture and release prothrombin from plasma with different wavelength light. Furthermore, this method can be widely applied to a variety of different protein separation process. PMID:26452827

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

    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

  1. EFFICACY OF THROMBIN FIBRIN GLUE AND SCLE ROSANT IN THE MANAGEMENT OF BLEEDI NG GASTRIC VARICES

    Sanjay Gupta

    2015-01-01

    Full Text Available Gastric varices are noted in up to 20 % of patents with portal hypertension , and are more common in those with non - cirrhotic etiology 1 . They bleed at lower portal pressures , bleed more severely and are associated with higher rates of rebleed , encephalopathy and mortality 1,2,3 . Variceal obliteration using tissue adhesives such as N - butyl cyanoacrylate leading to plugging and thrombosis of the gastric varices is currently the first line management option for obliteration of the gastric varices 3 . Although various options have been proposed , gold standard for management of gastric variceal bleeds is yet to be defined. We theorized that injection of the gastric varices using thrombin based glue followed by injection of a sclerosant shall be effective in optimum sclerotherapy and eradication of gastric varices. MATERIAL AND METHODS : All patients presenting with gastric variceal bleed were offered sclerotherapy with Thrombin fibrin based glue and sclerosant (TFG/S . During the study period 18 patients were enrolled in the TGF/S group. 21 patients underwent variceal plugging with n - butyl cyanoacrylate (NBC . There was no significant difference in age/ sex , duration of bleed or time interval between onset of bleed and endotherapy. RESULTS: Patients undergoing endotherapy with TGF/S had less episodes of bleed , and greater eradication of varices. CONCLUSION: The results with thrombin / fibrin glue and sclerotherapy are highly encouraging. Well - designed trials need to be performed KEYWORDS:Gastric varices; Thrombin Sclerotherapy

  2. Protein Z efficiently depletes thrombin generation in disseminated intravascular coagulation with poor prognosis.

    Lee, Nuri; Kim, Ji-Eun; Gu, Ja-Yoon; Yoo, Hyun Ju; Kim, Inho; Yoon, Sung-Soo; Park, Seonyang; Han, Kyou-Sup; Kim, Hyun Kyung

    2016-01-01

    Disseminated intravascular coagulation (DIC) is characterized by consumption of coagulation factors and anticoagulants. Thrombin generation assay (TGA) gives useful information about global hemostatic status. We developed a new TGA system that anticoagulant addition can deplete thrombin generation in plasma, which may reflect defective anticoagulant system in DIC. TGAs were measured on the calibrated automated thrombogram with and without thrombomodulin or protein Z in 152 patients who were suspected of having DIC, yielding four parameters including lag time, endogenous thrombin potential, peak thrombin and time-to-peak in each experiment. Nonsurvivors showed significantly prolonged lag time and time-to-peak in TGA-protein Z system, which was performed with added protein Z. In multivariate Cox regression analysis, lag time and time-to-peak in TGA system were significant independent prognostic factors. In TGA-protein Z system, lag time and time-to-peak were revealed as independent prognostic factors of DIC. Protein Z addition could potentiate its anticoagulant effect in DIC with poor prognosis, suggesting the presence of defective protein Z system. The prolonged lag time and time-to-peak in both TGA and TGA-protein Z systems are expected to be used as independent prognostic factors of DIC. PMID:26203764

  3. Recombinant Technology and Probiotics

    Icy D’Silva

    2011-09-01

    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.

  4. Recombinant Technology and Probiotics

    Icy DSilva

    2011-01-01

    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 molecule...

  5. Topical report review status

    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

  6. Crystallographic determination of the structures of human alpha-thrombin complexed with BMS-186282 and BMS-189090.

    Malley, M. F.; Tabernero, L; Chang, C.Y.; Ohringer, S. L.; Roberts, D.G.; J Das; Sack, J. S.

    1996-01-01

    The crystallographic structures of the ternary complexes of human alpha-thrombin with hirugen (a sulfated hirudin fragment) and the small-molecule active site thrombin inhibitors BMS-186282 and BMS-189090 have been determined at 2.6 and 2.8 A. In both cases, the inhibitors, which adopt very similar bound conformations, bind in an antiparallel beta-strand arrangement relative to the thrombin main chain in a manner like that reported for PPACK, D-Phe-Pro-Arg-CH2Cl. They do, however, exhibit dif...

  7. Autocrine production of basic fibroblast growth factor translated from novel synthesized mRNA mediates thrombin-induced mitogenesis in smooth muscle cells.

    Cucina, Alessandra; Borrelli, Valeria; Lucarelli, Marco; Sterpetti, Antonio V; Cavallaro, Antonino; Strom, Roberto; Santoro-D'Angelo, Luciana; Scarpa, Sigfrido

    2002-03-01

    Thrombin is known to stimulate smooth muscle cell (SMC) growth in culture but the mechanisms underlying growth stimulation remain unclear. Previous works have observed a significant increase in platelet-derived growth factor AA and basic fibroblast growth factor (bFGF) release by bovine aortic SMC after addition of thrombin. The aim of this study was to clarify the link between thrombin, bFGF and SMC proliferation by examining the kinetics of autocrine production of bFGF by thrombin-stimulated SMC and its contribution to thrombin-induced mitogenesis. Experiments were performed to assess the dynamics of thrombin-induced bFGF mRNA transcription and to distinguish, following thrombin stimulus, between the activation of 'old' bFGF protein and/or bFGF mRNA, or novel mRNA synthesis and subsequent translation. Bovine aortic SMCs were stimulated with thrombin in serum-free culture. bFGF mRNA expression was determined by RT-PCR. Mitogenic activity of thrombin was determined by 3H-thymidine uptake. Our results demonstrate that the peak of bFGF mRNA expression occurred 24 h after thrombin stimulation. Experiments performed with cycloheximide, a translation inhibitor, revealed a translation peak later than 24 h after thrombin stimulation. Thrombin-induced mitogenic activity in SMCs was partially inhibited by the addition of anti-bFGF antibody (p<0.001) and of hirudin (p<0.001). When hirudin was added 24 h after stimulation, thrombin-induced mitogenic activity was not inhibited. In conclusion, thrombin-induced mitogenesis was partially mediated by the autocrine production of bFGF, mainly due to protein synthesis by novel mRNA with a transcription peak at 24 h and a later translation peak. PMID:11835269

  8. Contrastive topics decomposed

    Michael Wagner

    2012-01-01

    The analysis of contrastive topics introduced in Bring 1997b and further developed in Bring 2003 relies on distinguishing two types of constituents that introduce alternatives: the sentence focus, which is marked by a FOC feature, and the contrastive topic, which is marked by a CT feature. A non-compositional rule of interpretation that refers to these features is used to derive a topic semantic value, a nested set of sets of propositions. This paper presents evidence for a correlation betw...

  9. Topical treatment of melasma

    Bandyopadhyay Debabrata

    2009-01-01

    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 ...

  10. [Topical therapy of rosacea].

    Schfer, H

    2013-07-01

    Metronidazole and azelaic acid are the only topical medications approved for rosacea. All other topical treatments for rosacea and its special forms are used off-label. Topical steroids are not indicated in rosacea, because of their side effects (induction of steroid rosacea, high risk of facial skin atrophy, and high risk of rebound after cessation of therapy). Topical as well as systemic steroids are allowed only as initial and short term therapy for acute forms of rosacea (e.g. rosacea fulminans). Papular and pustular rosacea is the major indication for topical therapy. Sebaceous gland and connective tissue hyperplasia in glandular-hypertrophic rosacea as well as erythema in erythematous rosacea do not respond well to topical measures. A new active substance, the alpha-2-adrenoreceptor agonist brimonidine, will be approved soon for the topical treatment of erythema in rosacea. All severe forms of rosacea should initially be treated with a combination of topical and systemic agents. After improvement of the clinical symptoms, topical treatment alone is usually adequate to maintain the control. PMID:23780475

  11. Diclofenac Topical (osteoarthritis pain)

    ... your medications or monitor you carefully for side effects.you should know that you should not apply sunscreens, cosmetics, lotions, moisturizers, insect repellents, or other topical medications ...

  12. Syntacticized topics in Kurmuk

    Andersen, Torben

    2015-01-01

    This article argues that Kurmuk, a little-described Western Nilotic language, is characterized by a syntacticized topic whose grammatical relation is variable. In this language, declarative clauses have as topic an obligatory preverbal NP which is either a subject, an object or an adjunct. The gr...

  13. Syntacticized topics in Kurmuk

    Andersen, Torben

    This article argues that Kurmuk, a little-described Western Nilotic language, is characterized by a syntacticized topic whose grammatical relation is variable. In this language, declarative clauses have as topic an obligatory preverbal NP which is either a subject, an object or an adjunct. The gr...

  14. Cardiovascular and biochemical studies on the effects of thrombin and dabigatran and the interaction with vasopressor molecules

    R. Anand

    2014-10-01

    Conclusion: The thrombin inhibitor, dabigatran reduces vascular oxidative stress and inflammation, improves endothelial function, and decreases atherosclerosis in rodents. [Int J Basic Clin Pharmacol 2014; 3(5.000: 874-878

  15. A near-infrared fluorescent bioassay for thrombin using aptamer-modified CuInS2 quantum dots

    We describe a near-infrared (NIR) fluorescent thrombin assay using a thrombin-binding aptamer (TBA) and Zn(II)-activated CuInS2 quantum dots (Q-dots). The fluorescence of Zn(II)-activated Q-dots is quenched by the TBA via photoinduced electron transfer, but if thrombin is added, it will bind to TBA to form G-quadruplexes and the Q-dots are released. As a result, the fluorescence intensity of the system is restored. This effect was exploited to design an assay for thrombin whose calibration plot, under optimum conditions, is linear in the 0.034 to 102 nmol L−1 concentration range, with a 12 pmol L−1 detection limit. The method is fairly simple, fast, and due to its picomolar detection limits holds great potential in the diagnosis of diseases associated with coagulation abnormalities and certain kinds of cancer. (author)

  16. Mutations in the fourth EGF-like domain affect thrombomodulin-induced changes in the active site of thrombin

    Koeppe, Julia R.; Beach, Muneera A.; Baerga-Ortiz, Abel; Jordan Kerns, S.; Komives, Elizabeth A.

    2008-01-01

    A number of alanine and more conservative mutants of residues in the fourth domain of thrombomodulin (TM) were prepared and assayed for protein C activation and for thrombin binding. Several of the alanine mutations appeared to cause misfolding or structural defects as assessed by poor expression and/or NMR HSQC experiments, while more conservative mutations at the same site appeared to fold correctly and retain activity. Several of the conservative mutants bound more weakly to thrombin despi...

  17. The involvement of a novel mechanism distinct from the thrombin receptor in the vasocontraction induced by trypsin

    Komuro, Taro; Miwa, Soichi; Minowa, Tetsuya; Okamoto, Yasuo; Enoki, Taijiro; Ninomiya, Haruaki; Zhang, Xiao-feng; Uemura, Yoshihiko; Kikuchi, Haruhiko; Masaki, Tomoh

    1997-01-01

    The vasocontracting effect of a serine protease trypsin and its mechanisms were investigated by monitoring the isometric tension in endothelium-denuded rings of rabbit thoracic aortae and its effects on intracellular free Ca2+ concentrations ([Ca2+]i) in dispersed rabbit vascular smooth muscle cells with a Ca2+ indicator fura-2. The actions of trypsin were compared with those of thrombin.Both thrombin and trypsin reversibly contracted aortic rings without endothelium in a concentration-depend...

  18. Cardiovascular and biochemical studies on the effects of thrombin and dabigatran and the interaction with vasopressor molecules

    Anand, R; Arumugasamy, K.; Manoj G Tyagi

    2014-01-01

    Background: The effect of serine protease thrombin and its directly acting inhibitor dabigatran were evaluated on the heart rate, blood pressure, and phospholipase C (PLC) enzyme activity and the intracellular calcium levels in the platelets. Methods: Heart rate and blood pressure were estimated using electrophysiology equipment. Results: While thrombin was unable to significantly affect the heart rate and blood pressure, the inhibitor dabigatran was able to reduce the heart rate apprec...

  19. The application of a modified nucleotide in aptamer selection: novel thrombin aptamers containing 5-(1-pentynyl)-2'-deoxyuridine.

    Latham, J.A.; Johnson, R.; Toole, J. J.

    1994-01-01

    Combinatorial libraries of nucleic acids are developing into novel sources for lead compounds in drug development. In order to diversify the pool of ss DNA sequences, we have used a modified nucleotide, 5-(1-pentynyl)-2'-deoxyuridine, in place of thymidine in a random nucleic acid library and screened this library against human thrombin. Previously, we described this screening method to identify a novel structural inhibitor (an aptamer) of the coagulation protease thrombin (Bock, L. et. al. (...

  20. Preoperative thrombin generation is predictive for the risk of blood loss after cardiac surgery: a research article

    Bosch, Yvonne; Al Dieri, Raed; ten Cate, Hugo; Nelemans, Patty; Bloemen, Saartje; Hemker, Coenraad; Weerwind, Patrick; Maessen, Jos; Mochtar, Baheramsjah

    2013-01-01

    Background In this study the value of thrombin generation parameters measured by the Calibrated Automated Thrombography for prediction of blood loss after cardiac surgery with cardiopulmonary bypass was investigated. Methods Thirty male patients undergoing first-time coronary artery bypass grafting were enrolled. Blood samples were taken pre-bypass before heparinisation (T1) and 5 min after protamine administration (T2). Thrombin generation was measured both in platelet-rich plasma and in pla...

  1. Binding of ?2-macroglobulin-thrombin complexes and methylamine-treated ?2-macroglobulin to human blood monocytes

    The binding of ?2-macroglobulin (?2M) to human peripheral blood monocytes was investigated. Monocytes, the precursors of tissue macrophages, were isolated from fresh blood by centrifugal elutriation or density gradient centrifugation. Binding studies were performed using 125I-labeled ?2M. Cells and bound ligand were separated from free ligand by rapid vacuum filtration. Nonlinear least-squares analysis of data obtained in direct binding studies at 00C showed that monocytes bound the ?2M-thrombin complex with a K/sub d/ 3.0 +- .09 nM and the monocyte had 1545 +- 153 sitescell. Thrombin alone did not compete for the site. Binding was divalent cation dependent. Direct binding studies also demonstrated that monocytes bound methylamine-treated ?2M in a manner similar to ?2M-thrombin. Competitive binding studies showed that ?2M-thrombin and methylamine-treated ?2M bound to the same sites on the monocyte. In contrast, native ?2M did not compete with ?2M-thrombin for the site. Studies done at 370C suggested that after binding, the monocyte internalized and degraded ?2M-thrombin and excreted the degradation products. Receptor turnover and degradation of ?2M-thrombin complexes were blocked in monocytes treated with chloroquine, an inhibitor of lysosomal function. The results indicate that human monocytes have a divalent cation dependent, high-affinity binding site for ?2M-thrombin and methylamine-treated ?2M which may function to clear ?2M-proteinase complexes from the circulation

  2. Recombinant DNA in Medicine

    Cederbaum, Stephen D.; Fareed, George C.; Lovett, Michael A.; Shapiro, Larry J.

    1984-01-01

    Studies in bacteria and bacterial viruses have led to methods to manipulate and recombine DNA in unique and reproducible ways and to amplify these recombined molecules millions of times. Once properly identified, the recombinant DNA molecules can be used in various ways useful in medicine and human biology. There are many applications for recombinant DNA technology. Cloned complementary DNA has been used to produce various human proteins in microorganisms. Insulin and growth hormone have been...

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

    Postenka Carl O

    2011-01-01

    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-ΔTC 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, αvβ5 integrin and β1 integrin. Relative to 468-OPN and 468-CON cells, 468-ΔTC cells expressing OPN with a deleted thrombin cleavage domain demonstrated decreased cell adhesion (p in vitro. Furthermore, injection of 468-ΔTC 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.

  4. Large-scale preparation of active caspase-3 in E. coli by designing its thrombin-activatable precursors

    Park Sung

    2008-12-01

    Full Text Available Abstract Background Caspase-3, a principal apoptotic effector that cleaves the majority of cellular substrates, is an important medicinal target for the treatment of cancers and neurodegenerative diseases. Large amounts of the protein are required for drug discovery research. However, previous efforts to express the full-length caspase-3 gene in E. coli have been unsuccessful. Results Overproducers of thrombin-activatable full-length caspase-3 precursors were prepared by engineering the auto-activation sites of caspase-3 precursor into a sequence susceptible to thrombin hydrolysis. The engineered precursors were highly expressed as soluble proteins in E. coli and easily purified by affinity chromatography, to levels of 10–15 mg from 1 L of E. coli culture, and readily activated by thrombin digestion. Kinetic evaluation disclosed that thrombin digestion enhanced catalytic activity (kcat/KM of the precursor proteins by two orders of magnitude. Conclusion A novel method for a large-scale preparation of active caspase-3 was developed by a strategic engineering to lack auto-activation during expression with amino acid sequences susceptible to thrombin, facilitating high-level expression in E. coli. The precursor protein was easily purified and activated through specific cleavage at the engineered sites by thrombin, generating active caspase-3 in high yields.

  5. Spectroscopic and Electrochemical Detection of Thrombin/5'-SH or 3'-SH Aptamer Immobilized on (porous) Gold Substrates

    Thrombin is a serine protease that catalyzes the conversion of soluble fibrinogen to insoluble fibrin, and thus induces physiological and pathological blood coagulation. Therefore, it is important to detect thrombin in blood serum for purposes of diagnosis. To achieve this goal, it has been suggested that a 15-mer aptamer strongly binds with thrombin to form a G-quartet structure of the aptamer. Generally, 5'-end thiol-functionalized aptamer has been used as an anti-thrombin binder. Herein, we evaluate the possibility of utilizing a 3'-SH aptasensor for thrombin detection using SPR spectroscopy, and compare the enhancement of the electrochemical signal of the thrombin-aptamer bound on a porous gold substrate. Although the two aptamers have similar configurations, in SPR analysis, the 3'-SH aptamer was a effective aptasensor as well as 5'-SH aptamer. Results from electrochemical analysis showed that the porous gold substrate acted as a good substrate for an aptasensor and demonstrated 5-fold enhancement of current change, as compared to gold thin film

  6. Amidino-containing Schiff base copper(II) and iron(III) chelates as a thrombin inhibitor.

    Toyota, Eiko; Sekizaki, Haruo; Takahashi, Yu-u; Itoh, Kunihiko; Tanizawa, Kazutaka

    2005-01-01

    Four series of Schiff base copper(II) and iron(III) chelates were synthesized from 4-formyl-3-hydroxybenzamidine or 3-formyl-4-hydroxybenzamidine and various L- or D-amino acids. Their inhibitory activities for bovine alpha-thrombin (abbreviated as thrombin) were determined. The most potent thrombin inhibitor in this series is copper(II) chelate (1g') derived from 4-formyl-3-hydroxybenzamidine and D-Trp. Its Ki value, 2.7x10(-8) M, is comparable to that of Argatroban (MD-805), which is a clinically used compound. The iron(III) chelates derived from 4-formyl-3-hydroxybenzamidine and hydrophobic L-amino acids (Val, Ile, Leu, Phe, Trp, Met) also exhibited higher inhibitory potency. It appears that coordination geometry composed of metal ion, amidino group, amino acid side chain is well accommodated to the thrombin active site. From the Ki values of Schiff base metal chelates for thrombin, the structure-activity relationships between the chelates and active site of thrombin were discussed. PMID:15635223

  7. Trypsin, Tryptase, and Thrombin Polarize Macrophages towards a Pro-Fibrotic M2a Phenotype.

    White, Michael J V; Gomer, Richard H

    2015-01-01

    For both wound healing and the formation of a fibrotic lesion, circulating monocytes enter the tissue and differentiate into fibroblast-like cells called fibrocytes and pro-fibrotic M2a macrophages, which together with fibroblasts form scar tissue. Monocytes can also differentiate into classically activated M1 macrophages and alternatively activated M2 macrophages. The proteases thrombin, which is activated during blood clotting, and tryptase, which is released by activated mast cells, potentiate fibroblast proliferation and fibrocyte differentiation, but their effect on macrophages is unknown. Here we report that thrombin, tryptase, and the protease trypsin bias human macrophage differentiation towards a pro-fibrotic M2a phenotype expressing high levels of galectin-3 from unpolarized monocytes, or from M1 and M2 macrophages, and that these effects appear to operate through protease-activated receptors. These results suggest that proteases can initiate scar tissue formation by affecting fibroblasts, fibrocytes, and macrophages. PMID:26407067

  8. Thrombin activation and liver inflammation in advanced hepatitis C virus infection

    González-Reimers, Emilio; Quintero-Platt, Geraldine; Martín-González, Candelaria; Pérez-Hernández, Onán; Romero-Acevedo, Lucía; Santolaria-Fernández, Francisco

    2016-01-01

    Hepatitis C virus (HCV) infection is associated with increased thrombotic risk. Several mechanisms are involved including direct endothelial damage by the HCV virus, with activation of tissue factor, altered fibrinolysis and increased platelet aggregation and activation. In advanced stages, chronic HCV infection may evolve to liver cirrhosis, a condition in which alterations in the portal microcirculation may also ultimately lead to thrombin activation, platelet aggregation, and clot formation. Therefore in advanced HCV liver disease there is an increased prevalence of thrombotic phenomena in portal vein radicles. Increased thrombin formation may activate hepatic stellate cells and promote liver fibrosis. In addition, ischemic changes derived from vascular occlusion by microthrombi favor the so called parenchymal extinction, a process that promotes collapse of hepatocytes and the formation of gross fibrous tracts. These reasons may explain why advanced HCV infection may evolve more rapidly to end-stage liver disease than other forms of cirrhosis.

  9. Determination of inhibitory potency of argatroban toward thrombin by electrophoretically mediated microanalysis.

    Pochet, Lionel; Servais, Anne-Catherine; Farcas, Elena; Bettonville, Virginie; Bouckaert, Charlotte; Fillet, Marianne

    2013-11-15

    Developing an EMMA method for enzymatic assay remains a challenge, particularly using UV detection. Indeed, it is necessary to optimize the separation conditions while allowing the enzymatic reaction to occur within the capillary respecting kinetic constraints and achieving enough sensitivity. In this work, such EMMA methodology was set up to evaluate the inhibitory potency of drugs toward thrombin, a serine protease implicated in the coagulation cascade. To achieve our goal, the separation buffer, the injection sequence, the internal standard and the chromogenic substrate were investigated. The newly developed system was then assessed determining the kinetic Km constant for the selected substrate and compared with the results obtained with a continuous spectrophotometer cell assay. Secondly, the Ki inhibitory constant of the thrombin inhibitor argatroban was determined and found in agreement with the published value. PMID:24148466

  10. Therapeutic Recombinant Monoclonal Antibodies

    Bakhtiar, Ray

    2012-01-01

    During the last two decades, the rapid growth of biotechnology-derived techniques has led to a myriad of therapeutic recombinant monoclonal antibodies with significant clinical benefits. Recombinant monoclonal antibodies can be obtained from a number of natural sources such as animal cell cultures using recombinant DNA engineering. In contrast to…

  11. Therapeutic Recombinant Monoclonal Antibodies

    Bakhtiar, Ray

    2012-01-01

    During the last two decades, the rapid growth of biotechnology-derived techniques has led to a myriad of therapeutic recombinant monoclonal antibodies with significant clinical benefits. Recombinant monoclonal antibodies can be obtained from a number of natural sources such as animal cell cultures using recombinant DNA engineering. In contrast to

  12. Ultrasound guided percutaneous thrombin injection for the treatment of iatrogenic pseudoaneurysms

    Elford, J; BURRELL, C; Roobottom, C

    1999-01-01

    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 ultrasoun...

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

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

    1994-01-01

    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 ...

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

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

    2011-01-01

    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...

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

    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

  16. Haemostasis in Thyroid Surgery: Collagen-Fibrinogen-Thrombin Patch versus Cellulose Gauze—Our Experience

    Nicola Tartaglia; Alessandra Di Lascia; Vincenzo Lizzi; Pasquale Cianci; Alberto Fersini; Antonio Ambrosi; Vincenzo Neri

    2016-01-01

    Purpose. Postoperative hemorrhage is fortunately uncommon but potentially life-threatening complication of thyroid surgery that increases the postoperative morbidity and the hospital stay. In this study we compare the efficacy of collagen patch coated with human fibrinogen and human thrombin (CFTP) (group C) and oxidized regenerated cellulose gauze (group B) versus traditional hemostatic procedures (group A) in thyroid surgery. Methods. From January 2011 to December 2013, 226 were eligible fo...

  17. Trypsin, Tryptase, and Thrombin Polarize Macrophages towards a Pro-Fibrotic M2a Phenotype

    White, Michael J. V.; Gomer, Richard H

    2015-01-01

    For both wound healing and the formation of a fibrotic lesion, circulating monocytes enter the tissue and differentiate into fibroblast-like cells called fibrocytes and pro-fibrotic M2a macrophages, which together with fibroblasts form scar tissue. Monocytes can also differentiate into classically activated M1 macrophages and alternatively activated M2 macrophages. The proteases thrombin, which is activated during blood clotting, and tryptase, which is released by activated mast cells, potent...

  18. In vivo fluorescence imaging of atherosclerotic plaques with activatable cell-penetrating peptides targeting thrombin activity

    Olson, Emilia S; Whitney, Michael A.; Friedman, Beth; Aguilera, Todd A.; Crisp, Jessica L; Baik, Fred M.; Jiang, Tao; Baird, Stephen M.; Tsimikas, Sotirios; Tsien, Roger Y.; Nguyen, Quyen T.

    2012-01-01

    Thrombin and other coagulation enzymes have been shown to be important during atherosclerotic disease development. Study of these proteases is currently limited because of lack of robust molecular imaging agents for imaging protease activity in vivo. Activatable cell penetrating peptides (ACPPs) have been used to monitor MMP activity in tumors and, in principle, can be modified to detect other proteases. We have developed a probe that incorporates the peptide sequence DPRSFL from the proteina...

  19. Posttraumatic pseudoaneurysm of medial plantar artery in a child: treatment with percutaneous thrombin injection

    Fabrício Neto Ladeira

    2014-03-01

    Full Text Available Pseudoaneurysms of the medial plantar artery are rare. The authors describe a case of a pseudoaneurysm of the medial plantar artery of a child who had suffered a penetrating laceration injury. Diagnosis can be confirmed using Doppler ultrasound and magnetic resonance angiography. As an alternative to the conventional surgery technique, percutaneous Doppler ultrasound-guided thrombin injection is a safe and effective treatment.

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

    Keeling, Aoife N

    2011-07-25

    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.

  1. Elevated Cytokines, Thrombin and PAI-1 in Severe HCPS Patients Due to Sin Nombre Virus

    Virginie Bondu

    2015-02-01

    Full Text Available Sin Nombre Hantavirus (SNV, Bunyaviridae Hantavirus is a Category A pathogen that causes Hantavirus Cardiopulmonary Syndrome (HCPS with case fatality ratios generally ranging from 30% to 50%. HCPS is characterized by vascular leakage due to dysregulation of the endothelial barrier function. The loss of vascular integrity results in non-cardiogenic pulmonary edema, shock, multi-organ failure and death. Using Electric Cell-substrate Impedance Sensing (ECIS measurements, we found that plasma samples drawn from University of New Mexico Hospital patients with serologically-confirmed HCPS, induce loss of cell-cell adhesion in confluent epithelial and endothelial cell monolayers grown in ECIS cultureware. We show that the loss of cell-cell adhesion is sensitive to both thrombin and plasmin inhibitors in mild cases, and to thrombin only inhibition in severe cases, suggesting an increasing prothrombotic state with disease severity. A proteomic profile (2D gel electrophoresis and mass spectrometry of HCPS plasma samples in our cohort revealed robust antifibrinolytic activity among terminal case patients. The prothrombotic activity is highlighted by acute ≥30 to >100 fold increases in active plasminogen activator inhibitor (PAI-1 which, preceded death of the subjects within 48 h. Taken together, this suggests that PAI-1 might be a response to the severe pathology as it is expected to reduce plasmin activity and possibly thrombin activity in the terminal patients.

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

    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

  3. Core-shell nanostructures for ultrasensitive detection of α-thrombin

    Chen, Xia; Liu, Hongli; Zhou, Xiaodong; Hu, Jiming

    2010-12-01

    We have synthesized a stable, sensitive and specific surface-enhanced Raman tag, and demonstrated its application in human α-thrombin detection. The tag consists of aptamer-modified core-shell nanoparticles with hydrophobic Au@Ag as core and silica as shell encapsulating Raman active molecules. By taking advantage of the Raman signal enhancement effect by metallic nanostructures, high stability and robustness of glass-coated core-shell nanostructures and the recognition capabilities of aptamers, we designed a sandwich detection for protein identification with high selectivity and sensitivity. In this way, we realized the ultrasensitive detection of α-thrombin. GDNs (glass-coated, dye-tagged nanoparticles), which were conjugated with oligonucleotides or antibodies, were extremely soluble in water, and had mechanical and chemical stability, easily controllable-size distribution and friendly biocompatibility. Specifically, the glass coating renders the particles amenable to use in many solvents without altering the Raman spectral response and makes agglomeration a nonfactor. All these merits open the door of the real applications in diagnostics or medical investigations in complex biofluids, such as human plasma and serum. Using the aptamer-modified GDNs as Raman tags, we successfully performed the detection of α-thrombin in human plasma. Furthermore, the overall method have been proved effective and selective, and may be implemented for multiplex target analysis simultaneously.

  4. Electrochemical Raduction Potential Shifts of Graphene Oxide Employed in Thrombin Detection

    Jeong, Hanall; Hwang, Shinjae; Kim, Kyuwon [Incheon National Univ., Incheon (Korea, Republic of)

    2014-06-15

    We have reported a feasibility study on thrombin detection by the measurement of peak potentials shifts for the electrochemical reduction of GO. Our novel strategy has demonstrated that the shifts are fairly dependent upon the concentration of target thrombin. We are extending this result to determine quantitatively various target material such as proteins, DNA, metal ions. The development of electrochemical biosensor is currently under the intense investigation owing to their great promise for rapid, convenience and low-cost detection of analytes. Especially, graphene oxide (GO), an oxygen-rich carbonaceous layered material, has attracted strong interest as an substrate material because of its own unique characteristics. Based on recent studies GO consists of intact graphitic regions interspersed with sp{sup 3}-hybridized carbons containing hydroxyl and epoxy functional groups on the top and bottom surfaces of each sheet and sp{sup 2}-hybridized carbons containing carboxylate and carbonyl groups principally at the sheet edges. The intrinsic oxygen-containing functional groups have been used as initial sites for deposition of biomolecules such as DNA and proteins on the GO sheets and provide the possibility to be an ideal platform for detecting of target materials. In addition, GO is electrochemically reducible, which enables it as an indicator or label for electrochemical sensor applications. Several studies have employed the GO-indicator to determine DNA, Hg{sup 2+}, and thrombin.

  5. Allosteric Partial Inhibition of Monomeric Proteases. Sulfated Coumarins Induce Regulation, not just Inhibition, of Thrombin

    Verespy III, Stephen; Mehta, Akul Y.; Afosah, Daniel; Al-Horani, Rami A.; Desai, Umesh R.

    2016-01-01

    Allosteric partial inhibition of soluble, monomeric proteases can offer major regulatory advantages, but remains a concept on paper to date; although it has been routinely documented for receptors and oligomeric proteins. Thrombin, a key protease of the coagulation cascade, displays significant conformational plasticity, which presents an attractive opportunity to discover small molecule probes that induce sub-maximal allosteric inhibition. We synthesized a focused library of some 36 sulfated coumarins to discover two agents that display sub-maximal efficacy (~50%), high potency (150-fold). Michaelis-Menten, competitive inhibition, and site-directed mutagenesis studies identified exosite 2 as the site of binding for the most potent sulfated coumarin. Stern-Volmer quenching of active site-labeled fluorophore suggested that the allosteric regulators induce intermediate structural changes in the active site as compared to those that display ~80–100% efficacy. Antithrombin inactivation of thrombin was impaired in the presence of the sulfated coumarins suggesting that allosteric partial inhibition arises from catalytic dysfunction of the active site. Overall, sulfated coumarins represent first-in-class, sub-maximal inhibitors of thrombin. The probes establish the concept of allosteric partial inhibition of soluble, monomeric proteins. This concept may lead to a new class of anticoagulants that are completely devoid of bleeding. PMID:27053426

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

    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.

  7. Electrochemical Raduction Potential Shifts of Graphene Oxide Employed in Thrombin Detection

    We have reported a feasibility study on thrombin detection by the measurement of peak potentials shifts for the electrochemical reduction of GO. Our novel strategy has demonstrated that the shifts are fairly dependent upon the concentration of target thrombin. We are extending this result to determine quantitatively various target material such as proteins, DNA, metal ions. The development of electrochemical biosensor is currently under the intense investigation owing to their great promise for rapid, convenience and low-cost detection of analytes. Especially, graphene oxide (GO), an oxygen-rich carbonaceous layered material, has attracted strong interest as an substrate material because of its own unique characteristics. Based on recent studies GO consists of intact graphitic regions interspersed with sp3-hybridized carbons containing hydroxyl and epoxy functional groups on the top and bottom surfaces of each sheet and sp2-hybridized carbons containing carboxylate and carbonyl groups principally at the sheet edges. The intrinsic oxygen-containing functional groups have been used as initial sites for deposition of biomolecules such as DNA and proteins on the GO sheets and provide the possibility to be an ideal platform for detecting of target materials. In addition, GO is electrochemically reducible, which enables it as an indicator or label for electrochemical sensor applications. Several studies have employed the GO-indicator to determine DNA, Hg2+, and thrombin

  8. [Heparin cofactor II, a thrombin inhibitor with a still not clarified physiologic role].

    Rossi, E B; Duboscq, C L; Kordich, L C

    1999-01-01

    Heparin Cofactor II (HCII) is a glycoprotein in human plasma which inactivates thrombin rapidly in the presence of dermatan sulfate. Inhibition occurs by formation of a stable equimolar complex between HCII and thrombin. HCII association with thrombotic events has not always been observed, thus decreased HCII does not appear to be a strong risk factor for thromboembolic events. Reduced HCII levels have been detected in different clinical conditions, such as hepatic failure, disseminated intravascular coagulation, thalasemina, sickle cell anemia. Increased physiological levels have been found in pregnant women and oral contraception. In our laboratory, we measured HCII plasmatic levels in the normal Buenos Aires city population and in patients under different clinical conditions, such as sepsis, diabetis, burns, oral anticoagulation and in patients treated with heparin, hyperhomcysteinemia in whom septic and diabetic patients showed decreased values. HCII thrombin inhibition possibly takes place in extravascular sites where dermatan sulfate is present. HCII activity would be important in the regulation of wound healing, inflammation, or neuronal development. PMID:10349131

  9. Direct thrombin inhibitor-bivalirudin functionalized plasma polymerized allylamine coating for improved biocompatibility of vascular devices.

    Yang, Zhilu; Tu, Qiufen; Maitz, Manfred F; Zhou, Shuo; Wang, Jin; Huang, Nan

    2012-11-01

    The direct thrombin inhibitor of bivalirudin (BVLD), a short peptide derived from hirudin, has drawn an increasing attention in clinical application because it is safer and more effective than heparin for diabetic patients with moderate- or high-risk for acute coronary syndromes (ACS). In this study, BVLD was covalently conjugated on plasma polymerized allylamine (PPAam) coated 316L stainless steel (SS) to develop an anticoagulant surface. QCM-D real time monitoring result shows that 56520 ng/cm2 of BVLD was bound to the PPAam surface. Infrared spectroscopy (IR) and X-ray photoelectron spectroscopy (XPS) confirmed the immobilization of BVLD. The conjugation of BVLD onto the PPAam coating led to enhanced binding of thrombin, and the activity of the thrombin adsorbed on its surface was effectively inhibited. As a result, the BVLD immobilized PPAam (BVLD-PPAam) substrate prolonged the clotting times, and exhibited inhibition in adhesion and activation of platelets and fibrinogen. We also found that the BVLD-PPAam coating significantly enhanced endothelial cell adhesion, proliferation, migration and release of nitric oxide (NO) and secretion of prostaglandin I2 (PGI2). In vivo results indicate that the BVLD-PPAam surface restrained thrombus formation by rapidly growing a homogeneous and intact endothelium on its surface. These data suggest the potential of this multifunctional BVLD-PPAam coating for the application not only in general vascular devices such as catheters, tubes, oxygenator, hemodialysis membranes but also vascular grafts and stents. PMID:22877639

  10. Aptamer-conjugated gold functionalized graphene oxide nanocomposites for human ?-thrombin specific recognition.

    Deng, Nan; Jiang, Bo; Chen, Yuanbo; Liang, Zhen; Zhang, Lihua; Liang, Yu; Yang, Kaiguang; Zhang, Yukui

    2016-01-01

    The specific recognition toward target proteins from complex biological samples has great potential in clinical diagnostics and therapeutics, receiving more and more attention. Herein, we achieved the specific detection of human ?-thrombin from human serum by aptamer-conjugated gold functionalized graphene oxide nanocomposites (denoted as Apt/Au/PEI/GO nanocomposites). Gold functionalized graphene oxide nanocomposites were synthesized by in situ growth of Au nanoparticles on graphene oxide surface using polyethylenimine as reducing and stabilizing reagents, and then it was used as support for aptamer immobilization through forming an Au-S bonding. The obtained Apt/Au/PEI/GO nanocomposites inherited not only the large surface area which made the immobilizing amount of aptamer up to 36.1nmol/mg, but also the excellent hydrophilicity which showed remarkable selectivity for human ?-thrombin specific recognition, even with the interference of 3000 fold human serum proteins. Furthermore, with its superior properties, Apt/Au/PEI/GO nanocomposites showed advantages of high capture efficiency (>86%) and excellent recognition repeatability. Finally, the Apt/Au/PEI/GO nanocomposites were successfully applied for human ?-thrombin specific recognition in human serum, verifying its great potential in clinical applications. PMID:26689824

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

    Tan, Nget Hong

    2010-01-01

    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

  12. Allosteric Partial Inhibition of Monomeric Proteases. Sulfated Coumarins Induce Regulation, not just Inhibition, of Thrombin.

    Verespy Iii, Stephen; Mehta, Akul Y; Afosah, Daniel; Al-Horani, Rami A; Desai, Umesh R

    2016-01-01

    Allosteric partial inhibition of soluble, monomeric proteases can offer major regulatory advantages, but remains a concept on paper to date; although it has been routinely documented for receptors and oligomeric proteins. Thrombin, a key protease of the coagulation cascade, displays significant conformational plasticity, which presents an attractive opportunity to discover small molecule probes that induce sub-maximal allosteric inhibition. We synthesized a focused library of some 36 sulfated coumarins to discover two agents that display sub-maximal efficacy (~50%), high potency (150-fold). Michaelis-Menten, competitive inhibition, and site-directed mutagenesis studies identified exosite 2 as the site of binding for the most potent sulfated coumarin. Stern-Volmer quenching of active site-labeled fluorophore suggested that the allosteric regulators induce intermediate structural changes in the active site as compared to those that display ~80-100% efficacy. Antithrombin inactivation of thrombin was impaired in the presence of the sulfated coumarins suggesting that allosteric partial inhibition arises from catalytic dysfunction of the active site. Overall, sulfated coumarins represent first-in-class, sub-maximal inhibitors of thrombin. The probes establish the concept of allosteric partial inhibition of soluble, monomeric proteins. This concept may lead to a new class of anticoagulants that are completely devoid of bleeding. PMID:27053426

  13. Contrastive topics decomposed

    Michael Wagner

    2012-12-01

    Full Text Available The analysis of contrastive topics introduced in Bring 1997b and further developed in Bring 2003 relies on distinguishing two types of constituents that introduce alternatives: the sentence focus, which is marked by a FOC feature, and the contrastive topic, which is marked by a CT feature. A non-compositional rule of interpretation that refers to these features is used to derive a topic semantic value, a nested set of sets of propositions. This paper presents evidence for a correlation between the restrictive syntax of nested focus operators and the syntax of contrastive topics, a correlation which is unexpected under this analysis. A compositional analysis is proposed that only makes use of the flatter focus semantic values introduced by focus operators. The analysis aims at integrating insights from the original analysis while at the same time capturing the observed syntactic restrictions. http://dx.doi.org/10.3765/sp.5.8 BibTeX info

  14. Sparse Topical Coding

    Zhu, Jun

    2012-01-01

    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.

  15. Topics in Nuclear Astrophysics

    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.)

  16. Salicylic Acid Topical

    ... scaling or overgrowth of skin cells such as psoriasis (a skin disease in which red, scaly patches ... and patch to apply to the skin or scalp. Topical salicylic acid comes in several strengths, including ...

  17. Topical photodynamic therapy

    Polja?ki Mirjana

    2006-01-01

    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.

  18. Towards Big Topic Modeling

    Yan, Jian-feng; Zeng, Jia; Liu, Zhi-qiang; GAO, YANG

    2013-01-01

    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 scalability, we p...

  19. Topical treatment of melasma

    Bandyopadhyay Debabrata

    2009-01-01

    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.

  20. Thrombin-induced intracellular calcium rise identifies oligodendrocytes derived from SVZ cultures

    S. Grade

    2009-08-01

    Full Text Available Glial cell transplantation arises as a promising complementary strategy to challenge oligodendrocytes loss occurring in the demyelinated brain. Recent advances in stem cell biology, namely concerning subventricular zone (SVZ stem cells have been giving new hopes offering a source of new oligodendrocytes for cell replenishment in MS brains. However, there are yet no good methods for the functional identification of differentiating oligodendrocytes, and pharmacological analysis in these cells prior transplantation.In the present study, we questioned whether SVZ-derived oligodendrocytes could be functionally discriminated on the basis of variations of intracellular calcium levels ([Ca2+]i following 50 mM KCl, 100 ?M histamine or 0,1 U/ml thrombin stimulations. For this purpose, P1-3 C57/BL6 mice SVZ cultures were treated with triiodo-L-thyronine (T3 to promote oligodendrocytic differentiation before functional analysis of the heterogeneous population. Our group has previously shown that SVZ-derived neurons and immature cells can be discriminated due to their selective [Ca2+]i rise upon KCl and histamine stimulations, respectively. Herein, we demonstrate that O4-oligodendrocytes, as observed previously in astrocytes, do not respond to these stimuli. Nonetheless, O4-oligodendrocytes display an increase in [Ca2+]i following thrombin stimulation whereas all the other cell types in the culture were insensitive to thrombin. Thus, oligodendrocytes can be distinguished according to the uniqueness of their response to thrombin.We further show that thrombin-induced calcium increase in SVZ-derived oligodendrocytes is mediated by protease-activated receptor-1 activation with the downstream involvement of Gq/11 and PLC, resulting in the mobilization of calcium from the cellular internal stores.This method allows the analysis of functional properties of the oligodendrocytic cell population in living SVZ cultures which is of major interest for the development of efficient grafting strategies in the demyelinated brain. Furthermore, this technique opens new perspectives for the search of new pro-oligodendrogenic factors to be used prior grafting. Ackowledgments:PTDC/SAU-NEU/68465/2006, FEDER

  1. Topical Drugs for Pain Relief

    Anjali Srinivasan

    2015-03-01

    Full Text Available Topical therapy helps patients with oral and perioral pain problems such as ulcers, burning mouth syndrome, temporomandibular disorders, neuromas, neuropathies and neuralgias. Topical drugs used in the field of dentistry are topical anaesthetics, topical analgesics, topical antibiotics and topical corticosteroids. It provides symptomatic/curative effect. Topical drugs are easy to apply, avoids hepatic first pass metabolism and more sites specific. But it can only be used for medications that require low plasma concentrations to achieve a therapeutic effect.

  2. Direct Thrombin Inhibition Reduces Lung Collagen, Accumulation, and Connective Tissue Growth Factor mRNA Levels in Bleomycin-Induced Pulmonary Fibrosis

    Howell, David C.J.; Goldsack, Neil R.; Richard P. Marshall; McAnulty, Robin J; Starke, Richard; Purdy, Gordon; Laurent, Geoffrey J.; Chambers, Rachel C

    2001-01-01

    Dramatic activation of the coagulation cascade has been extensively documented for pulmonary fibrosis associated with acute and chronic lung injury. In addition to its role in hemostasis, thrombin exerts profibrotic effects via activation of the major thrombin receptor, protease-activated receptor-1. In this study, we examined the effect of the direct thrombin inhibitor, UK-156406 on fibroblast responses in vitro and on bleomycin-induced pulmonary fibrosis in rats. UK-156406 significantly inh...

  3. Discriminative Relational Topic Models.

    Chen, Ning; Zhu, Jun; Xia, Fei; Zhang, Bo

    2015-05-01

    Relational topic models (RTMs) provide a probabilistic generative process to describe both the link structure and document contents for document networks, and they have shown promise on predicting network structures and discovering latent topic representations. However, existing RTMs have limitations in both the restricted model expressiveness and incapability of dealing with imbalanced network data. To expand the scope and improve the inference accuracy of RTMs, this paper presents three extensions: 1) unlike the common link likelihood with a diagonal weight matrix that allows the-same-topic interactions only, we generalize it to use a full weight matrix that captures all pairwise topic interactions and is applicable to asymmetric networks; 2) instead of doing standard Bayesian inference, we perform regularized Bayesian inference (RegBayes) with a regularization parameter to deal with the imbalanced link structure issue in real networks and improve the discriminative ability of learned latent representations; and 3) instead of doing variational approximation with strict mean-field assumptions, we present collapsed Gibbs sampling algorithms for the generalized relational topic models by exploring data augmentation without making restricting assumptions. Under the generic RegBayes framework, we carefully investigate two popular discriminative loss functions, namely, the logistic log-loss and the max-margin hinge loss. Experimental results on several real network datasets demonstrate the significance of these extensions on improving prediction performance. PMID:26353322

  4. Characters and Topical Diversity

    Eriksson, Rune

    The purpose of this article is to contribute to our understanding of the difference between the bestseller and the non-bestseller in nonfiction. It is noticed that many bestsellers in nonfiction belongs to the sub-genre of creative nonfiction, but also that the topics in this kind of literature is...... largely ignored by the critics. Thus, the article tests how topics may work in creative nonfiction. Two Danish bestsellers belonging to the genre, Frank’s Mit smukke genom ( My Beautiful Genome), about genomics, and Buk-Swienty’s Slagtebænk Dybbøl ( ‘Slaughter-bench Dybbøl’), a history book, are chosen as...... cases and analysed using a slightly modified motif model by Johansen. The result is that in both books the main topic is treated from a double perspective, but also that six out of seven secondary topics, or motifs, are treated as well. It is concluded that also in a topical sense creative nonfiction...

  5. A label-free and high sensitive aptamer biosensor based on hyperbranched polyester microspheres for thrombin detection

    Sun, Chong [Jiangsu Key Laboratory of Biofunctional Materials, Biomedical Functional Materials Collaborative Innovation Center, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023 (China); Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014 (China); Han, Qiaorong [Jiangsu Key Laboratory of Biofunctional Materials, Biomedical Functional Materials Collaborative Innovation Center, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023 (China); Wang, Daoying; Xu, Weimin [Institute of Agricultural Products Processing, Jiangsu Academy of Agricultural Sciences, Nanjing 210014 (China); Wang, Weijuan [Jiangsu Key Laboratory of Biofunctional Materials, Biomedical Functional Materials Collaborative Innovation Center, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023 (China); Zhao, Wenbo, E-mail: zhaowenbo@njnu.edu.cn [Jiangsu Key Laboratory of Biofunctional Materials, Biomedical Functional Materials Collaborative Innovation Center, College of Chemistry and Materials Science, Nanjing Normal University, Nanjing 210023 (China); Zhou, Min, E-mail: zhouminnju@126.com [Department of Vascular Surgery, the Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing 210008 (China)

    2014-11-19

    Highlights: • A label-free thrombin aptamer biosensor applied in whole blood has been developed. • The aptamer biosensor showed a wide detection range and a low detection limit. • The antibiofouling idea utilized for biosensor is significant for diagnostics. - Abstract: In this paper, we have synthesized hyperbranched polyester microspheres with carboxylic acid functional groups (HBPE-CA) and developed a label-free electrochemical aptamer biosensor using thrombin-binding aptamer (TBA) as receptor for the measurement of thrombin in whole blood. The indium tin oxide (ITO) electrode surface modified with HBPE-CA microspheres was grafted with TBA, which has excellent binding affinity and selectivity for thrombin. Binding of the thrombin at the modified ITO electrode surface greatly restrained access of electrons for a redox probe of [Fe(CN){sub 6}]{sup 3−/4−}. Moreover, the aptamer biosensor could be used for detection of thrombin in whole blood, a wide detection range (10 fM–100 nM) and a detection limit on the order of 0.90 fM were demonstrated. Control experiments were also carried out by using bull serum albumin (BSA) and lysozyme in the absence of thrombin. The good stability and repeatability of this aptamer biosensor were also proved. We expect that this demonstration will lead to the development of highly sensitive label-free sensors based on aptamer with lower cost than current technology. The integration of the technologies, which include anticoagulant, sensor and nanoscience, will bring significant input to high-performance biosensors relevant to diagnostics and therapy of interest for human health.

  6. A label-free and high sensitive aptamer biosensor based on hyperbranched polyester microspheres for thrombin detection

    Highlights: A label-free thrombin aptamer biosensor applied in whole blood has been developed. The aptamer biosensor showed a wide detection range and a low detection limit. The antibiofouling idea utilized for biosensor is significant for diagnostics. - Abstract: In this paper, we have synthesized hyperbranched polyester microspheres with carboxylic acid functional groups (HBPE-CA) and developed a label-free electrochemical aptamer biosensor using thrombin-binding aptamer (TBA) as receptor for the measurement of thrombin in whole blood. The indium tin oxide (ITO) electrode surface modified with HBPE-CA microspheres was grafted with TBA, which has excellent binding affinity and selectivity for thrombin. Binding of the thrombin at the modified ITO electrode surface greatly restrained access of electrons for a redox probe of [Fe(CN)6]3?/4?. Moreover, the aptamer biosensor could be used for detection of thrombin in whole blood, a wide detection range (10 fM100 nM) and a detection limit on the order of 0.90 fM were demonstrated. Control experiments were also carried out by using bull serum albumin (BSA) and lysozyme in the absence of thrombin. The good stability and repeatability of this aptamer biosensor were also proved. We expect that this demonstration will lead to the development of highly sensitive label-free sensors based on aptamer with lower cost than current technology. The integration of the technologies, which include anticoagulant, sensor and nanoscience, will bring significant input to high-performance biosensors relevant to diagnostics and therapy of interest for human health

  7. Recombination and chromosome segregation.

    Sherratt, David J.; Søballe, Britta; Barre, François-Xavier; Filipe, Sergio; Lau, Ivy; Massey, Thomas; Yates, James

    2004-01-01

    The duplication of DNA and faithful segregation of newly replicated chromosomes at cell division is frequently dependent on recombinational processes. The rebuilding of broken or stalled replication forks is universally dependent on homologous recombination proteins. In bacteria with circular chromosomes, crossing over by homologous recombination can generate dimeric chromosomes, which cannot be segregated to daughter cells unless they are converted to monomers before cell division by the con...

  8. Thrombin inhibits HMGB1-mediated proinflammatory signaling responses when endothelial protein C receptor is occupied by its natural ligand

    Jong-Sup Bae

    2013-11-01

    Full Text Available High mobility group box 1 (HMGB1 is involved in thepathogenesis of vascular diseases. Unlike activated protein C(APC, the activation of PAR-1 by thrombin is known to elicitproinflammatory responses. To determine whether the occupancyof EPCR by the Gla-domain of APC is responsible for thePAR-1-dependent antiinflammatory activity of the protease, wepretreated HUVECs with the PC zymogen and then activatedPAR-1 with thrombin. It was found that thrombin downregulatesthe HMGB1-mediated induction of both TNF-α andIL-6 and inhibits the activation of both p38 MAPK and NF-κB inHUVECs pretreated with PC. Furthermore, thrombin inhibitedHMGB1-mediated hyperpermeability and leukocyte adhesion/migration by inhibiting the expression of cell adhesion moleculesin HUVECs if EPCR was occupied. Collectively, theseresults suggest the concept that thrombin can initiate proinflammatoryresponses in vascular endothelial cells through theactivation of PAR-1 may not hold true for normal vesselsexpressing EPCR under in vivo conditions. [BMB Reports 2013;46(11: 544-549

  9. Magnetic relaxation switch and colorimetric detection of thrombin using aptamer-functionalized gold-coated iron oxide nanoparticles

    We describe a sensitive biosensing system combining magnetic relaxation switch diagnosis and colorimetric detection of human α-thrombin, based on the aptamer-protein interaction induced aggregation of Fe3O4-Au nanoparticles. To demonstrate the concept, gold-coated iron oxide nanoparticle was synthesized by iterative reduction of HAuCl4 onto the dextran-coated Fe3O4 nanoparticles. The resulting core-shell structure had a flowerlike shape with pretty narrow size distribution (referred to as 'nanorose'). The two aptamers corresponding to human α-thrombin were conjugated separately to two distinct nanorose populations. Once a solution containing human α-thrombin was introduced, the nanoroses switched from a well dispersed state to an aggregated one, leading to a change in the spin-spin relaxation time (T2) as well as the UV-Vis absorption spectra of the solution. Thus the qualitative and quantitative detection method for human α-thrombin was established. The dual-mode detection is clearly advantageous in obtaining a more reliable result; the detection range is widened as well. By using the dual-mode detection method, a detectable T2 change is observed with 1.0 nM human α-thrombin, and the detection range is from 1.6 nM to 30.4 nM.

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

    Elliott John T

    2005-02-01

    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.

  11. Thrombin stimulation of synthesis and secretion of fibronectin by human A549 epithelial cells and mouse LB fibroblasts

    Thrombin, a serine protease generated at wound sites, takes part in multiple biological functions, including wound healing. The present report elucidates the effect of thrombin on fibronectin (FN) synthesis and secretion in fibroblasts and epithelial cells. Subconfluent cultures of mouse LB fibroblasts and human A549 epithelial cells were exposed to various concentrations of bovine plasma thrombin at 37 degrees C for 16 hr. After exposure, cells were processed for determination of cell-associated and secreted FN by metabolic labeling, immunoprecipitation, immunofluorescence, and peroxidase immunocytochemistry. The correlation of FN production with cell growth was studied by a combined procedure of peroxidase immunocytochemistry and light microscopic autoradiography. The amounts of cell-associated and secreted FN were significantly increased with dose increments of thrombin. The increases were most evident in secreted FN. The increase of cell-associated FN was also evidenced by results from immunofluorescence and immunocytochemical studies. Ultrastructurally, the intracellular FN was localized in rough endoplasmic reticulum, Golgi complexes, and secretory granules, whereas non-released extracellular FN was localized in the plasma membrane of cell-to-cell contacts and in the extracellular fibrils. More intense cytoplasmic FN staining was observed in cells that were not labeled with [3H]-thymidine, indicating that FN production may vary with different phases of cell growth. The results imply that thrombin may play an important role in the early phases of wound healing

  12. Signal amplification aptamer biosensor for thrombin based on a glassy carbon electrode modified with graphene, quantum dots and gold nanoparticles

    Xie, Lingling; You, Liqin; Cao, Xiaoyu

    2013-05-01

    A novel electrogenerated chemiluminescence (ECL) assay for sensitive determination of thrombin is designed employing CdSe/ZnS quantum dots served as an ECL label. This ECL sensor is fabricated on graphene modified glassy carbon electrode which is then covered with a low surface coverage of gold nanoparticles (AuNPs). An aptamer is used to selectively recognize the target. The thiol-terminated aptamer is first immobilized on AuNPs/graphene modified electrode, and then thrombin is imported to form the aptamer-thrombin complexes. After blocking the nonspecifically bound oligonucleotides with MCH solution, another CdSe/ZnS quantum dots modified aptamer is hybridized with the free thiol-terminated aptamer to form a DNA complexe. A decreased ECL signal is observed upon recognition of the target thrombin. The integrated ECL intensity versus the concentration of thrombin is linear in the range from 0.01 to 50 nM. The detection limit is 10 fM. The present aptasensor also exhibits excellent selectivity, stability and reusability. This sensing system can provide a promising label-free model for aptamer-based compounds sensitive detection.

  13. A brief exposure to tryptase or thrombin potentiates fibrocyte differentiation in the presence of serum or serum amyloid p.

    White, Michael J V; Galvis-Carvajal, Elkin; Gomer, Richard H

    2015-01-01

    A key question in both wound healing and fibrosis is the trigger for the initial formation of scar tissue. To help form scar tissue, circulating monocytes enter the tissue and differentiate into fibroblast-like cells called fibrocytes, but fibrocyte differentiation is strongly inhibited by the plasma protein serum amyloid P (SAP), and healthy tissues contain very few fibrocytes. In wounds and fibrotic lesions, mast cells degranulate to release tryptase, and thrombin mediates blood clotting in early wounds. Tryptase and thrombin are upregulated in wound healing and fibrotic lesions, and inhibition of these proteases attenuates fibrosis. We report that tryptase and thrombin potentiate human fibrocyte differentiation at biologically relevant concentrations and exposure times, even in the presence of concentrations of serum and SAP that normally completely inhibit fibrocyte differentiation. Fibrocyte potentiation by thrombin and tryptase is mediated by protease-activated receptors 1 and 2, respectively. Together, these results suggest that tryptase and thrombin may be an initial trigger to override SAP inhibition of fibrocyte differentiation to initiate scar tissue formation. PMID:25429068

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

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

    2013-01-08

    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/Apt2apoferritin NPsHRP was formed by the affinity reactions between AuMNPsApt1, thrombin, and Apt2apoferritinHRP. 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. --------------------------------------------------------------------------------

  15. Design, synthesis and antithrombotic evaluation of novel dabigatran etexilate analogs, a new series of non-peptides thrombin inhibitors.

    Chen, Dongxing; Wang, Shaochi; Diao, Xiaojuan; Zhu, Qihua; Shen, Huiliang; Han, Xueqing; Wang, Yiwei; Gong, Guoqing; Xu, Yungen

    2015-12-01

    Thrombin is a serine protease that plays a key role in blood clotting, which makes it a promising target for the treatment of thrombotic diseases. Dabigatran is direct potent thrombin inhibitor. Based on bioisosteric and scaffold hopping principle, two dabigatran mimics (I-1 and II-1) in which the benzamidine moiety of dabigatran was replaced by a tricyclic fused scaffold were designed, synthesized and evaluated for their in vitro activities for inhibiting thrombin. The results reveal that compounds I-1 (IC50=9.20nM) and II-1 (IC50=7.48nM) are potent direct thrombin inhibitors and the activity is in the range of reference drug. On this basis, twenty-two ester and carbamate derivatives of I-1 or II-1 were prepared and evaluated for their anticoagulant activity. Prodrugs I-4a (IC50=0.73?M), I-4b (IC50=0.75?M), II-2a (IC50=1.44?M) and II-2b (IC50=0.91?M) display excellent effects of inhibiting thrombin induced-platelet aggregation. Moreover, compounds I-9 and II-4, which contain a cleavable moiety with anti-platelet activity, show the best anticoagulant efficacy among the tested compounds in the rat venous thrombosis model. The compounds which have better in vitro and in vivo activity were subjected to rat tail bleeding test, and the result demonstrates that compound I-9 is less likely to have bleeding risk than dabigatran etexilate. PMID:26537784

  16. Fluorescence correlation spectroscopy of gold nanoparticles, and its application to an aptamer-based homogeneous thrombin assay

    We have studied the fluorescence properties and diffusion behaviors of gold nanoparticles (GNPs) in solution by using fluorescence correlation spectroscopy (FCS) at single molecule level. The GNPs display a high photo-saturation feature. Under illumination with strong laser light, they display higher brightness per particle (BPP) despite their low quantum yields. Based on the unique fluorescence properties and diffusion behaviors of GNPs, we have developed a sensitive and homogenous thrombin assay. It is based on a sandwich strategy and is making use of GNPs to which two different aptamers are conjugated. When the differently aptamer-labeled GNPs are mixed with solutions containing thrombin, the affinity reaction causes the GNPs to form dimers or oligomers. This leads to an increase in the diffusion time of the GNPs in the detection volume that is seen in FCS. The FCS method enables sensitive detection of the change in the characteristic diffusion time of the GNPs before and after the affinity reaction. Quantitative analysis of thrombin is based on the measurement of the change in the diffusion time. Under optimal conditions, the calibration plot is linear in the 0.5 nM to 110 nM thrombin concentration range, and the detection limit is 0.5 nM. The method was successfully applied to the direct determination of thrombin in human plasma. (author)

  17. Magnetic relaxation switch and colorimetric detection of thrombin using aptamer-functionalized gold-coated iron oxide nanoparticles

    Liang Guohai; Cai Shaoyu; Zhang Peng [Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433 (China); Peng Youyuan [Department of Chemistry, Quanzhou Normal University, Quanzhou 362000 (China); Chen Hui; Zhang Song [Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433 (China); Kong Jilie, E-mail: jlkong@fudan.edu.cn [Department of Chemistry and Institutes of Biomedical Sciences, Fudan University, Shanghai 200433 (China)

    2011-03-18

    We describe a sensitive biosensing system combining magnetic relaxation switch diagnosis and colorimetric detection of human {alpha}-thrombin, based on the aptamer-protein interaction induced aggregation of Fe{sub 3}O{sub 4}-Au nanoparticles. To demonstrate the concept, gold-coated iron oxide nanoparticle was synthesized by iterative reduction of HAuCl{sub 4} onto the dextran-coated Fe{sub 3}O{sub 4} nanoparticles. The resulting core-shell structure had a flowerlike shape with pretty narrow size distribution (referred to as 'nanorose'). The two aptamers corresponding to human {alpha}-thrombin were conjugated separately to two distinct nanorose populations. Once a solution containing human {alpha}-thrombin was introduced, the nanoroses switched from a well dispersed state to an aggregated one, leading to a change in the spin-spin relaxation time (T{sub 2}) as well as the UV-Vis absorption spectra of the solution. Thus the qualitative and quantitative detection method for human {alpha}-thrombin was established. The dual-mode detection is clearly advantageous in obtaining a more reliable result; the detection range is widened as well. By using the dual-mode detection method, a detectable T{sub 2} change is observed with 1.0 nM human {alpha}-thrombin, and the detection range is from 1.6 nM to 30.4 nM.

  18. Topics for Mathematics Clubs.

    Dalton, LeRoy C., Ed.; Snyder, Henry D., Ed.

    The ten chapters in this booklet cover topics not ordinarily discussed in the classroom: Fibonacci sequences, projective geometry, groups, infinity and transfinite numbers, Pascal's Triangle, topology, experiments with natural numbers, non-Euclidean geometries, Boolean algebras, and the imaginary and the infinite in geometry. Each chapter is…

  19. Selected topics in magnetism

    Gupta, L C

    1993-01-01

    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.

  20. Topics in Nonlinear Dynamics

    Mosekilde, Erik

    Through a significant number of detailed and realistic examples this book illustrates how the insights gained over the past couple of decades in the fields of nonlinear dynamics and chaos theory can be applied in practice. Aomng the topics considered are microbiological reaction systems, ecological...

  1. Advanced Topics in Aerodynamics

    Filippone, Antonino

    1999-01-01

    "Advanced Topics in Aerodynamics" is a comprehensive electronic guide to aerodynamics,computational fluid dynamics, aeronautics, aerospace propulsion systems, design and relatedtechnology. We report data, tables, graphics, sketches,examples, results, photos, technical andscientific literature, for...... higher education, learning, reference, research and engineering services....

  2. Differential Topic Models.

    Chen, Changyou; Buntine, Wray; Ding, Nan; Xie, Lexing; Du, Lan

    2015-02-01

    In applications we may want to compare different document collections: they could have shared content but also different and unique aspects in particular collections. This task has been called comparative text mining or cross-collection modeling. We present a differential topic model for this application that models both topic differences and similarities. For this we use hierarchical Bayesian nonparametric models. Moreover, we found it was important to properly model power-law phenomena in topic-word distributions and thus we used the full Pitman-Yor process rather than just a Dirichlet process. Furthermore, we propose the transformed Pitman-Yor process (TPYP) to incorporate prior knowledge such as vocabulary variations in different collections into the model. To deal with the non-conjugate issue between model prior and likelihood in the TPYP, we thus propose an efficient sampling algorithm using a data augmentation technique based on the multinomial theorem. Experimental results show the model discovers interesting aspects of different collections. We also show the proposed MCMC based algorithm achieves a dramatically reduced test perplexity compared to some existing topic models. Finally, we show our model outperforms the state-of-the-art for document classification/ideology prediction on a number of text collections. PMID:26353238

  3. Topic Tracking with Dynamic Topic Model and Topic-based Weighting Method

    Xiaoyan Zhang

    2010-05-01

    Full Text Available In topic tracking, a topic is usually described by several stories. How to represent a topic is always an issue and a difficult problem in the research on topic tracking. To emphasis the topic in stories, we provide an improved topic-based tf*idf weighting method to measure the topical importance of the features in the representation model. To overcome the topic drift problem and filter the noise existed in the tracked topic description, a dynamic topic model is proposed based on the static model. It extends the initial topic model with the information from the incoming related stories and filters the noise using the latest unrelated story. The topic tracking systems are implemented on the TDT4 Chinese corpus. The experimental results indicate that both the new weighting method and the dynamic model can improve the tracking performance.

  4. Enzyme-guided plasmonic biosensor based on dual-functional nanohybrid for sensitive detection of thrombin.

    Yan, Jing; Wang, Lida; Tang, Longhua; Lin, Lei; Liu, Yang; Li, Jinghong

    2015-08-15

    Rapid and sensitive methodologies for the detection of protein are in urgent requirement for clinic diagnostics. Localized surface plasmon resonance (LSPR) of metal nanostructures has the potential to circumvent this problem due to its sensitive optical properties and strong electromagnetic near-field enhancements. In this work, an enzyme mediated plasmonic biosensor on the basis of a dual-functional nanohybrid was developed for the detection of thrombin. By utilizing LSPR-responsive nanohybrid and anaptamer-enzyme conjugated reporting probe, the sensing platform brings enhanced signal, stability as well as simplicity. Enzymatic reaction catalyzed the reduction of Au(3+) to Au° in situ, further leading to the rapid crystal growth of gold nanoparticles (AuNPs). The LSPR absorbance band and color changed company with the nanoparticle generation, which can be real-time monitoring by UV-visible spectrophotometer and naked eye. Nanohybrid constructed by gold and magnetic nanoparticles acts as a dual functional plasmonic unit, which not only plays the role of signal production, but also endows the sensor with the function of magnetic separation. Simultaneously, the introduction of enzyme effectively regulates the programming crystal growth of AuNPs. In addition, enzyme also serves as signal amplifier owing to its high catalysis efficiency. The response of the plasmonic sensor varies linearly with the logarithmic thrombin concentration up to 10nM with a limit of detection of 200 pM. The as-proposed strategy shows good analytical performance for thrombin determination. This simple, disposable method is promising in developing universal platforms for protein monitoring, drug discovery and point-of-care diagnostics. PMID:25845332

  5. Differential proteolytic activation of factor VIII-von Willebrand factor complex by thrombin

    Blood coagulation factor VIII (fVIII) is a plasma protein that is decreased or absent in hemophilia A. It is isolated as a mixture of heterodimers that contain a variably sized heavy chain and a common light chain. Thrombin catalyzes the activation of fVIII in a reaction that is associated with cleavages in both types of chain. The authors isolated a serine protease from Bothrops jararacussu snake venom that catalyzes thrombin-like heavy-chain cleavage but not light-chain cleavage in porcine fVIII as judged by NaDodSO4/PAGE and N-terminal sequence analysis. Using a plasma-free assay of the ability of activated 125I-fVIII to function as a cofactor in the activation of factor X by factor IXa, they found that fVIII is activated by the venom enzyme. The venom enzyme-activated fVIII was isolated in stable form by cation-exchange HPLC. von Willebrand factor inhibited venom enzyme-activated fVIII but not thrombin-activated fVIII. These results suggest that the binding of fVIII to von Willebrand factor depends on the presence of an intact light chain and that activated fVIII must dissociate from von Willebrand factor to exert its cofactor effect. Thus, proteolytic activation of fVIII-von Willebrand factor complex appears to be differentially regulated by light-chain cleavage to dissociate the complex and heavy-chain cleavage to activate the cofactor function

  6. Use of dressing with human fibrin and thrombin during resection of a right atrial angiosarcoma

    Bochenek, Maciej; Kapelak, Bogusław; Bartuś, Krzysztof; Urbańczyk, Małgorzata; Sadowski, Jerzy

    2015-01-01

    Primary malignant cardiac tumors are rare and are usually detected at an advanced stage of disease. Their location and infiltration often hinder surgical resection. Tissue sarcomas, especially angiosarcomas, are composed of irregular and delicate vascular tissue. The resection of such tumors from the heart is associated with a high risk of life-threatening bleeding that cannot be stopped with traditional surgical methods. We present a case report of the application of a dressing containing human fibrin and thrombin in order to prevent bleeding during the partial resection of advanced cardiac angiosarcoma in a 40-year-old patient. PMID:26336498

  7. PREFACE: CEWQO Topical Issue CEWQO Topical Issue

    Bozic, Mirjana; Man'ko, Margarita

    2009-09-01

    This topical issue of Physica Scripta collects selected peer-reviewed contributions based on invited and contributed talks and posters presented at the 15th Central European Workshop on Quantum Optics (CEWQO) which took place in Belgrade 29 May-3 June 2008 (http://cewqo08.phy.bg.ac.yu). On behalf of the whole community took place in Belgrade 29 May-3 June 2008 (http://cewqo08.phy.bg.ac.yu, cewqo08.phy.bg.ac.yu). On behalf of the whole community of the workshop, we thank the referees for their careful reading and useful suggestions which helped to improve all of the submitted papers. A brief description of CEWQO The Central European Workshop on Quantum Optics is a series of conferences started informally in Budapest in 1992. Sometimes small events transform into important conferences, as in the case of CEWQO. Professor Jozsef Janszky, from the Research Institute of Solid State Physics and Optics, is the founder of this series. Margarita Man'ko obtained the following information from Jozsef Janszky during her visit to Budapest, within the framework of cooperation between the Russian and Hungarian Academies of Sciences in 2005. He organized a small workshop on quantum optics in Budapest in 1992 with John Klauder as a main speaker. Then, bearing in mind that a year before Janszky himself was invited by Vladimir Buzek to give a seminar on the same topic in Bratislava, he decided to assign the name 'Central European Workshop on Quantum Optics', considering the seminar in Bratislava to be the first workshop and the one in Budapest the second. The third formal workshop took place in Bratislava in 1993 organized by Vladimir Buzek, then in 1994 (Budapest, by Jozsef Janszky), 1995 and 1996 (Budmerice, Slovakia, by Vladimir Buzek), 1997 (Prague, by Igor Jex), 1999 (Olomouc, Czech Republic, by Zdenek Hradil), 2000 (Balatonfüred, Hungary, by Jozsef Janszky ), 2001 (Prague, by Igor Jex), 2002 (Szeged, Hungary, by Mihaly Benedict), 2003 (Rostock,Germany, by Werner Vogel and Sascha Wallentowitz), 2004 (Trieste, Italy, by Naseem Rahman and Sascha Wallentowitz), 2005 (Bilkent, Ankara, by Alexander Shumovsky), 2006 (Vienna, by Helmut Rauch), 2007 (Palermo, Italy, by Antonino Messina) and 2008 (Belgrade, by Mirjana Bozic). The CEWQO series developed in two directions following the rapid development of quantum optics and the transitional development of the scientific collaboration of Central European researchers with researchers from old and new emerging Central European countries, and from all over the world. The topics discussed at CEWQO 08 were divided into ten groups that aimed to cover the broad scope of modern quantum optics: Fundamental aspects of quantum optics and quantum mechanics Single photons and photon pairs Cavity and circuit QED Atoms in intense fields Neutron, atom and molecular quantum optics Quantum gases and fluids Coherence, entanglement and decoherence Optical properties of condensed matter and nanostructures Open quantum systems and chaos Quantum information processing Central European Workshops on Quantum Optics realize and are consistent with a wider idea, and a social, economical, cultural and political program promoted since 1989 by the Central European Initiative (CEI), the main goal of which was to help transition countries in Central Europe to become closer to the EU. The resulting support of the CEI, first obtained thanks to the scientific reputation, organizing activities, and efforts of Helmut Rauch, has been very important for the organization of the CEWQO in recent years, particularly in 2008. The support of the Sixth and Seventh Framework Programs of the European Commission was also very important. A short review of papers in this topical issue A principal role in this topical issue is played by the photon. Vuletic et al describe the mapping of the photon-polarization state onto a single collective-spin excitation (magnon) shared between two atomic ensembles. A heralded quantum memory based on this mapping is demonstrated. Dodonov derives a formula which predicts a photon generation rate in a cavity due to strong variations of the complex dielectric function in a thin layer near an ideally conducting wall (simulation of the dynamic Casimir effect). Skenderovic reports how photons from two femptosecond laser pulses prepare a large molecule in a coherent superposition of vibrational states. The time evolution of this state is interrogated with a third (delayed) pulse which creates a fourth wave, the signal, giving information on the molecular dynamics. Dimitrova et al present lecture demonstrations of interference and quantum erasing with single photons. By considering electromagnetic energy flow lines as photon paths Davidovic et al explain the emergence of an interference pattern in the process of the accumulation of single photon events behind an interference grating. Atoms in a cavity, atom-atom interactions, interactions of atoms with photons and macroscopic bodies is the next important topic in this topical issue. Khanbekyan et al deal with the problem of the spontaneous emission of an excited atom in a high-Q cavity and investigate the regime when the emitted photon belongs to a wave packet simultaneously located inside and outside the cavity. Sambale et al study the resonant Casimir-Polder potential of an excited atom in front of meta-material half-space and show that for long distances it exhibits attenuated oscillations, while close to the surface the potential becomes attractive or repulsive. Buhmann et al study the nonequilibrium Casimir-Polder force on an atom prepared in an incoherent superposition of internal energy-eigenstates, which is placed in a magnetoelectric environment of nonuniform temperature. Lazarou et al discuss how two atoms, interacting with a single cavity, can be coherently evolved into an entangled state when they are controlled by a sequence of Gaussian pulses, named frequency chirps. Bougouffa et al report on field quantization between two parallel conducting plates (modifications of the decay rate between such plates) and the three-level Jaynes-Cummings dynamics in the single-mode regime. Tomas studies the interaction between two atoms, one excited and the other in its ground state near the interface between two media. It is shown that the nonretarded van der Waals force gets enhanced by almost three orders of magnitude at the surface mode resonance. Vuskovic et al write about the plasma treatment of a bulk Nb surface which is very efficient for producing high-Q factor microwave cavities. Nemeth et al review the theory and experiments of the coherently pumped micromaser. With varied atomic inversion in a coherently pumped micromaser, a sudden switch occurs between two distinctively different field states, with high and low photon numbers. Moi et al show that alkali-metal atoms adsorbed either in organic films or in porous glass are released into the vapor phase (desorbed) under illumination, the action of many photons. Several papers are devoted to matter-wave interference and quantum fluids. By analyzing unavoidable quantum losses as they appear in neutron phase-echo and spin rotation experiments, Rauch concludes that basic quantum irreversibility exists in neutron interferometry. Rauch also shows how entanglement effects in a single particle system demonstrate quantum contextuality, and then argues that a quantum system carries much more information than is usually extracted. The time evolution of the wave function of an atom hit by a photon in a three-grating interferometer is used by Arsenovic et al to interpret the intriguing results of the corresponding experiment by Chapman et al. Grujic et al demonstrate dark Raman resonance due to Ramsey interference in a spatially separated pump and probe laser beams co-propagating through a pure 87Rb vapor cell. Obtained EIT profiles are explained by solving Bloch's equations for an atom in a magnetic field moving through pump and probe laser regions. Gawlik et al present results of experiments on finite-temperature Bose-Einstein condensate of 87Rb atoms in a magnetic trap. In the Thomas-Fermi (TF) regime, the condensate dynamics has a hydrodynamic character. The dynamics of non-TF condensates reflect the interaction between BEC and non-condensed thermal atoms. Atoms in intense fields is the subject of several papers. Gainutdinov et al show that the contribution to the radiative shift of the side bands of the Mollow spectrum is very significant. Using Gell-Mann, Low S-matrix formalism, and QED, Glushkov et al present an approach to study multiphoton processes during the interaction of an atom with a realistic intense laser field. The paper by Khetselius is devoted to two related problems: the calculation of the atomic hyperfine structure of the Li-like ions and an estimation of the effectiveness of the three-step scheme of isotope separation for the case of Cs isotopes. Vvedenskii et al present the results concerning the excitation of a residual quasi-dc current in the plasma, which are based on the solution of the time-dependent Schrödinger equation for the hydrogen atom in a few-cycle laser pulse. Information processing is one of the important aspects of this issue and it is considered in several papers. M Man'ko et al presented a new notion of tomographic entropy and new entropic uncertainty relations applied to the problem of light propagation in optical fibers. Nonlinearity in the quantum-information processing is considered in the paper by Chirkin et al. D'Arrigo et al investigated a very specific semiclassical Hamiltonian model of a quantum memory channel. They evaluated the performance of the three-qubit code error correcting code by means of entanglement fidelity. The fundamental aspects of quantum optics are the subject of several papers, namely, Bell's inequalities are studied in the paper by Andreev, the star-product quantization scheme was discussed by O Man'ko, and probabilistic representation was investigated in the paper by Adam et al. In the paper by V Man'ko et al the diagonal representation of the density operator (usually called P-function of Glauber-Sudarshan) is related to the star-product quantization method and to the tomographic-probability representation of quantum states. Laskowski et al suggest an elegant geometrical criterion for the separability, which is based on the local correlation measurements readily available in the laboratory. Mizrahi describes a method to derive the Pauli-Schrödinger equation starting from a simple model of a qubit carried by a massive particle. By analyzing unavoidable quantum losses as they appear in neutron phase-echo and spin rotation experiments, Rauch concludes that basic quantum irreversibility exists in neutron interferometry. Rauch also shows how entanglement effects in a single particle system demonstrate quantum contextuality, and then argues that a quantum system carries much more information than is usually extracted. Kupczynski advocates various statistical tests which could be used to search for a fine structure in experimental data in order to answer the question: is quantum theory predictably complete? For an ion confined within a Paul trap, Mihalcea constructs an invariant operator based on the Lews and Riesenfeld approach and determines the spectrum of the quasienergy operator. Popov et al construct pair-coherent states of the Barut-Girardello kind for two noninteracting subsystems of pseudoharmonic oscillators and examine their statistical properties in different regions of parameters. The property of entanglement, considered to be the most intriguing property of composite quantum systems, has been an important research subject in recent years. It is considered to be a possible resource for quantum computation and communication. Therefore, a substantial number of papers in this topical issue is devoted to entanglement. Leon et al write that two-photon emission from two atoms initially excited in a common electromagnetic vacuum may generate atom-atom entanglement. Dömötör et al elucidate a connection between entanglement and coherent states. Earlier they proved that in the symmetric subspace of a system of N qubits a pure state is not globally entangled, if and only if, it is a coherent state. Here they extend this proof to a system of N 'quKits' (subsystems of arbitrary finite dimension K). Napoli et al compute exactly localizable entanglement as a function of temperature for the system of three interacting spins in a thermal state. Isar considers entanglement in open quantum dynamics by studying the system of two independent oscillators interacting with the general environment. He proposes some special parameters of the environment that manifest interesting properties (e.g., the environment is entangling initially separable states). Lindén et al study the decay of entanglement in rings of qubits that live in the Markov environment. They use the entanglement of formation as the measure whose time evolution announces (or not) the decay. Jivulescu et al consider the time evolution of a spin-1/2 particle nonuniformly coupled through the Heisenberg interaction to the environment composed of N spins. Considering arbitrary initial conditions the authors determine a numerically manipulative general solution from which information on full dynamics may be extracted. Ferraro et al investigate the entanglement evolution of two qubits interacting with a common environment through a Heisenberg XX mechanism and show that the phenomena of entanglement hidden death and entanglement hidden revival take place. Stochastic processes have been very important in quantum optics. Pascazio et al review and compare three algorithms for the generation of sequences of symmetric stable Levy random variables. They draw conclusions on the efficiency of the algorithms used and on some applications in quantum optics. Hul et al report on the possibilities of explaining the statistical properties of the spectra of irregular quantum systems by invoking the random matrix theory. The authors calculated the spectra, spectral correlation functions, and the distributions of avoided crossings, for two types of idealized model of one-dimensional quantum wires forming a quantum graph. Sirko et al present the experimental study of microwave networks displaying an irregular hexagonal structure. In a sense, these networks model quantum graphs with special properties. Kiss et al consider the recurrence of quantum walks on lattices by studying the properties of the generalized Polya number. The properties of this number are compared for classical and quantum cases. A number of interesting papers are devoted to the optical properties of condensed matter and nanostructures. Gorelik derives analytical expressions for photonic dispersion law in 3D photonic crystals filled by dielectrics or metal. Nemilentsau et al evaluate the photon density of states near a single-wall finite length carbon nanotube. The authors found definite singularities in the density of photon states that may be observable in light-matter interaction, thermal radiation distribution, and micromechanical phenomena related to Casimir forces. Perinova et al pay attention to the interesting relationship between microscopic and macroscopic approaches to the quantization of the electromagnetic field in the medium. They examine the problem of a source atom radiating into a dielectric. Radovanovic et al present an extended approach for estimating the tunneling times through all linear materials, including metamaterials having a negative refractive index. Vasic et al describe the optical design of 2D confined structures with metamaterial layers which is based on coordinate transformations. Using the Green's functions method, Ilic et al analyze the influence of boundaries of the molecular ultrathin film on exciton dispersion law. Jeknic-Dugic proposes the model of optically induced transitions in an electronic subsystem of a bio-molecule that is able to describe relatively slow conformational transitions of a bio-molecule. Stef et al present their goal to grow good quality YbF3-doped and PbF2-codoped CaF2 crystals with high divalent Ytterbium content for investigating the influence of Pb2+ ions on the valence conversion, on the dielectric and optical absorption spectra. Vasile et al present the fabrication and SEM and photoluminescence characterization of zinc gallate doped with Eu and Er ions. The results could be important for photonic applications of spinels. Vasiljevic et al present the process of production of microlenses by irradiation of a tot'hema eosin sensitized gelatin (TESG) layer with a laser beam (2nd Nd:YAG harmonic, 532 nm). Microlenses chemically processed after production with 10% alum solution had near diffraction limited performance. The production and application of microlenses are fast expanding because they are increasingly used in biomedical and general optics. Prizes for the poster presentations Authors under 35 years of age were invited to take part in the poster competition. Two first prizes EX-AEQUOAE were awarded to Zoran Grujic from the Institute of Physics, Belgrade, Serbia, for the poster 'Numerical simulation of Raman-Ramsey effects induced by thermal motion of rubidium atoms' and to Andrey Popov from Altai State Technical University, Bernaul, Russia, for the poster 'Beryllium atoms in intense fields'. The third prize was awarded to Alex Crosse from Imperial College, London, UK, for the poster 'Quantum electrodynamics in absorbing nonlinear media'. Members of the Jury were: Mirjana Bozic (Chairperson), Victor Dodonov, Margarita Man'ko, Helmut Rauch, Saverio Pascazio, Richard Tanas and Philip Walther. Sponsors of the awards were the Institute of Physics, Belgrade, European Physical Journal (EPJ) and John Wiley and Sons. CEWQO 2009 and 2010 The 16th Central European Workshop on Quantum Optics was held in Turku, Finland, 23-27 May 2009. CEWQO09 was chaired by Professor Kalle-Antti Suominen (http://www.congress.utu.fi/cewqo2009). The conference site is the new ICT building at chaired by Professor Kalle-Antti Suominen (http://www.congress.utu.fi/cewqo2009, www.congress.utu.fi/cewqo2009). The conference site was the new ICT building at the University of Turku campus area and the Viking Line ferry boat. Turku is the central city of historical Finland established on the mouth of the river Aura in the 13th century. It is the birthplace of Finnish academic life, since the Academy of Turku was established there in 1640. In 2011, Turku will be one of the cultural capitals of Europe. The city has a strong maritime tradition and is shielded from the Baltic sea by a large and beautiful archipelago. The 17th Central European Workshop on Quantum Optics will be held in 2010 in St Andrews, UK. It will be chaired by Professors Ulf Leonhardt and Natalia Korolkova from the School of Physics and Astronomy, University of St Andrews. St Andrews is home to the first university of Scotland, the third-oldest in the English-speaking world, and is the home of golf. It remains a charming, eccentric seaside town that is sufficiently secluded - the ideal place for a stimulating and thought-provoking conference.

  8. Discovering Health Topics in Social Media Using Topic Models

    Paul, Michael J; Dredze, Mark

    2014-01-01

    By aggregating self-reported health statuses across millions of users, we seek to characterize the variety of health information discussed in Twitter. We describe a topic modeling framework for discovering health topics in Twitter, a social media website. This is an exploratory approach with the goal of understanding what health topics are commonly discussed in social media. This paper describes in detail a statistical topic model created for this purpose, the Ailment Topic Aspect Model (ATAM...

  9. Topics in molecular interactions

    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.)

  10. Aptamer-based fluorescent solid-phase thrombin assay using a silver-coated glass substrate and signal amplification by glucose oxidase

    We describe an aptamer-based solid-state biosensor for the fluorometric determination of thrombin. The surface of silver-coated glass was modified with the thrombin-binding aptamer 1 (TBA 1) of the sequence 5′-HS-TTT TTT TTT TTT TTT GGT TGG TGT GGT TGG-3′. A second (and biotinylated) thrombin -binding aptamer (TBA 2) with the sequence 5′-biotin-AGT CCG TGG TAG GGC AGG TTG GGG TGA CT-3′ was applied as the signaling aptamer. Following binding of thrombin by TBA 1 on the surface, TBA 2 is added and then binds to the thrombin on the surface of the silver-coated glass to form the thrombin-aptamer complex. The biotin groups on TBA 2 are then coated with streptavidin, and biotin-labeled glucose oxidase (biotin-GOx) is added to bind to streptavidin. The quantity of GOx immobilized in this way is directly related to the quantity of thrombin bound on the surface. Following cleavage of the aptamer with DNase I, glucose is added and oxidized by GOx to yield H2O2. Horseradish peroxidase is added and causes the oxidation of 3-p-hydroxyphenylpropanoic acid to yield a fluorescent product. The intensity of the blue fluorescence is directly related to the thrombin concentration in the 300 pM to 6500 pM range, and the detection limit is as low as 82 pM. The assay has good selectivity and practicability. (author)

  11. Topics in industrial mathematics

    Mathematical methods are widely used to solve practical problems arising in modern industry. This article outlines some of the topics relevant to AECL programmes. This covers the applications of transmission and neutron transport tomography to determine density distributions in rocks and two phase flow situations. Another example covered is the use of variational methods to solve the problems of aerosol migration and control theory. (author). 7 refs

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

    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. 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-ΔTC) or an empty vector (468-CON) and assessed for in vitro and in vivo functional differences in malignant/metastatic behavior. All three cell lines were found to equivalently express thrombin, tissue factor, CD44, αvβ5 integrin and β1 integrin. Relative to 468-OPN and 468-CON cells, 468-ΔTC cells expressing OPN with a deleted thrombin cleavage domain demonstrated decreased cell adhesion (p < 0.001), decreased mRNA expression of MCAM, maspin and TRAIL (p < 0.01), and increased uPA expression and activity (p < 0.01) in vitro. Furthermore, injection of 468-ΔTC cells into the mammary fat pad of nude mice resulted in decreased primary tumor latency time (p < 0.01) and increased primary tumor growth and lymph node metastatic burden (p < 0.001) compared to 468-OPN and 468-CON cells. 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

  13. Do avian mitochondria recombine?

    Berlin, Sofia; Smith, Nick G C; Ellegren, Hans

    2004-02-01

    The dogma of strict maternal inheritance of mitochondria is now being tested with population genetics methods on sequence data from many species. In this study we investigated whether recombination occurs in the mitochondria of the blue tit ( Parus caeruleus) by studying polymorphisms in the mitochondrial control region and in a recently identified (A)(n) microsatellite on the W chromosome. The female heterogamety of avian sex chromosomes allows a test of whether mitochondrial recombination affects genealogical inference by comparison of mitochondrial and W-linked sequence variation. There is no discrepancy between mitochondrial and W-linked genealogies in blue tits, consistent with no recombination. We also analyzed mitochondrial sequence variation in both blue tits and peregrine falcons ( Falco peregrinus) using a coalescent-based approach which accounts for recurrent mutation; in neither bird species did we find evidence of recombination. We conclude that it is unlikely that mitochondrial recombination has large effects on mitochondrial genetic variability in birds. PMID:15042336

  14. [New hemostatic therapy of bleeding of bladder by technique of drip-irrigation using a thrombin solution].

    Kimura, S; Nakamura, S; Nakai, H

    1986-02-01

    To control the bleeding from the bladder caused by radiation cystitis or transurethral surgery, drip-irrigation of bladder by indwelling a three-way Foley catheter using a thrombin solution, as a clotting agent, was done in 10 patients. Five hundreds ml of solution containing 25,000 units of thrombin was dripped out within 3 hours and repeated 2 times a day for 2 to 7 days. The results were excellent in 2 cases, good in 6 cases and poor in 2 cases. No remarkable side effects were observed. PMID:3524153

  15. Acidic Residues C-Terminal to the A2 Domain Facilitate Thrombin-Catalyzed Activation of Factor VIII

    Newell, Jennifer L.; Fay, Philip J.

    2008-01-01

    Factor VIII is activated by thrombin through proteolysis at Arg740, Arg372, and Arg1689. One region implicated in this exosite-dependent interaction is the factor VIII a2 segment (residues 711-740) separating the A2 and B domains. Residues 717-725 (DYYEDSYED) within this region consist of five acidic residues and three sulfo-Tyr residues, thus representing a high density of negative charge potential. The contributions of these residues to thrombin-catalyzed activation of factor VIII were asse...

  16. Computational study of some benzamidine-based inhibitors of thrombin-like snake venom proteinases

    Henriques, Elsa S.; Nascimento, Marco A. C.; Ramos, Maria João

    Pit viper venoms contain a number of serine proteinases that, despite their observed coagulant thrombin-like action in vitro, exhibit a paradoxical benign defibrinogenating (anticoagulant) action in vivo, with clinical applications in preventing thrombi and improved blood circulation. Considering that several benzamidine-based inhibitors, some highly selective to thrombin, also inhibit the enzymatic activity of such venombins, the modeling of their enzyme-inhibitor interactions could provide valuable information on the topological factors that determine the divergences in activity. The first step, and the object of the present study, was to derive the necessary set of parameters, consistent with the CHARMM force field, and to perform molecular dynamics (MD) simulations on a few selected representatives of the inhibitors in question under physiological conditions. Bonding and van der Waals parameters were derived by analogy to similar ones in the existing force field. Net atomic charges were obtained with a restrained fitting to the molecular electrostatic potential generated at B3LYP/6-31G(d) level. The parameters were refined to reproduce the available experimental geometries and crystal data, and the MD simulations of the free inhibitors in aqueous solution at 298 K provided an insightful description of their available conformational space.

  17. A sensitive HIV-1 envelope induced fusion assay identifies fusion enhancement of thrombin

    Cheng, De-Chun; Zhong, Guo-Cai; Su, Ju-Xiang [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Liu, Yan-Hong [Second Affiliated Hospital of Harbin Medical University, 246 Xuefu Road, Harbin, Heilongjiang 150081 (China); Li, Yan; Wang, Jia-Ye [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Hattori, Toshio [Department of Emerging Infectious Diseases, Division of Internal Medicine, Graduate School of Medicine, Tohoku University, Sendai 9808574 (Japan); Ling, Hong, E-mail: lingh@ems.hrbmu.edu.cn [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Department of Parasitology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Key Lab of Heilongjiang Province for Infection and Immunity, Key Lab of Heilongjiang Province Education Bureau for Etiology, Harbin, Heilongjiang 150081 (China); Zhang, Feng-Min, E-mail: fengminzhang@yahoo.com.cn [Department of Microbiology, Harbin Medical University, 194 Xuefu Road, Harbin, Heilongjiang 150081 (China); Key Lab of Heilongjiang Province for Infection and Immunity, Key Lab of Heilongjiang Province Education Bureau for Etiology, Harbin, Heilongjiang 150081 (China)

    2010-01-22

    To evaluate the interaction between HIV-1 envelope glycoprotein (Env) and target cell receptors, various cell-cell-fusion assays have been developed. In the present study, we established a novel fusion system. In this system, the expression of the sensitive reporter gene, firefly luciferase (FL) gene, in the target cells was used to evaluate cell fusion event. Simultaneously, constitutively expressed Renilla luciferase (RL) gene was used to monitor effector cell number and viability. FL gave a wider dynamic range than other known reporters and the introduction of RL made the assay accurate and reproducible. This system is especially beneficial for investigation of potential entry-influencing agents, for its power of ruling out the false inhibition or enhancement caused by the artificial cell-number variation. As a case study, we applied this fusion system to observe the effect of a serine protease, thrombin, on HIV Env-mediated cell-cell fusion and have found the fusion enhancement activity of thrombin over two R5-tropic HIV strains.

  18. A sensitive HIV-1 envelope induced fusion assay identifies fusion enhancement of thrombin

    To evaluate the interaction between HIV-1 envelope glycoprotein (Env) and target cell receptors, various cell-cell-fusion assays have been developed. In the present study, we established a novel fusion system. In this system, the expression of the sensitive reporter gene, firefly luciferase (FL) gene, in the target cells was used to evaluate cell fusion event. Simultaneously, constitutively expressed Renilla luciferase (RL) gene was used to monitor effector cell number and viability. FL gave a wider dynamic range than other known reporters and the introduction of RL made the assay accurate and reproducible. This system is especially beneficial for investigation of potential entry-influencing agents, for its power of ruling out the false inhibition or enhancement caused by the artificial cell-number variation. As a case study, we applied this fusion system to observe the effect of a serine protease, thrombin, on HIV Env-mediated cell-cell fusion and have found the fusion enhancement activity of thrombin over two R5-tropic HIV strains.

  19. Plasma thrombin-cleaved osteopontin elevation after carotid artery stenting in symptomatic ischemic stroke patients

    Atherothrombosis is the primary pathophysiology that underlies ischemic cerebral infarction. Osteopontin (OPN) is produced in atherosclerotic lesions and is cleaved by activated thrombin. We hypothesized that the rupture or damage of an unstable atherosclerotic plaque increases plasma levels of thrombin-cleaved OPN (trOPN). This study included 90 patients who received carotid angioplasty with stenting (CAS), 23 patients with essential hypertension (EHT) and 10 patients who were treated with carotid endarterectomy (CEA). The CAS patient group included 36 patients that had pre- and post-operative blood tests, diffusion-weighted imaging (DWI) using cerebral MRIs and estimated thrombus debris within the protection device. Immunohistochemistry of CEA specimens revealed that trOPN was detected around intra-plaque vessels. The highest tertile of plasma trOPN levels in CAS patients was higher than trOPN levels in EHT patients. Post-operative trOPN levels were significantly higher in symptomatic compared with asymptomatic patients (P=0.003). New ipsilateral DWI-positive patients revealed higher post-operative trOPN levels (P=0.003) and a higher grade of thrombi (P<0.001) than DWI-negative patients. TrOPN may be a novel biomarker that reflects the atherothrombotic status in ischemic stroke. (author)

  20. Mechanism of the Anticoagulant Activity of Thrombin Mutant W215A/E217A

    Gandhi, Prafull S.; Page, Michael J.; Chen, Zhiwei; Bush-Pelc, Leslie; Di Cera, Enrico; (WU-MED)

    2009-09-15

    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 {beta}-strand, and whether binding of thrombomodulin to exosite I can allosterically shift the E* form to the active E form to restore activity toward protein C are issues of considerable mechanistic importance to improve the design of an anticoagulant thrombin mutant for therapeutic applications. Here we present four crystal structures of WE in the human and murine forms that confirm the collapsed conformation reported previously under different experimental conditions and crystal packing. We also present structures of human and murine WE bound to exosite I with a fragment of the platelet receptor PAR1, which is unable to shift WE to the E form. These structural findings, along with kinetic and calorimetry data, indicate that WE is strongly stabilized in the E* form and explain why binding of ligands to exosite I has only a modest effect on the E*-E equilibrium for this mutant. The E* {yields} E transition requires the combined binding of thrombomodulin and protein C and restores activity of the mutant WE in the anticoagulant pathway.

  1. Module-activity relationship of G-quadruplex based DNA aptamers for human thrombin.

    Zavyalova, E; Golovin, A; Pavlova, G; Kopylov, A

    2013-01-01

    G-quadruplex based DNA aptamers for human thrombin are promising pharmaceuticals as anticoagulants. Initially discovered 15-mer DNA aptamer (15-TBA) has a minimal G-quadruplex structure which is able to inhibit thrombin. 15-TBA was modified and extended to improve aptamer activity and in vivo stability providing 31-TBA, NU172, RA-36, and some others as successful examples. In this paper an interplay between G-quadruplex (pharmacophore module) and additional modules has been studied. An original turbidimetric assay and conventional coagulation tests were applied to evaluate both inhibitory activity and type of inhibiting for aptamers constructed by exchanging the modules between 31- TBA and NU172. Additional modules strongly affect pharmacophore module inhibitory activity either enhancing or reducing it. RA-36 aptamer has two putative pharmacophore entities which also interplay being functionally non-equal. 5'- truncated RA-36 has half of the activity of RA-36, and the same as for 15-TBA. On the contrary 3'-truncated RA-36 has intermediate activity in between 15-TBA and RA-36. These results indicate fine regulation of G-quadruplex inhibitory activity by additional modules, as well as non-trivial behavior of joined pharmacophore modules. PMID:24083606

  2. Topics in Operator Theory

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

    2010-01-01

    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.

  3. Topics in circular statistics

    Jammalamadaka, S Rao

    2001-01-01

    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

  4. Topics in field theory

    Karpilovsky, G

    1989-01-01

    This monograph gives a systematic account of certain important topics pertaining to field theory, including the central ideas, basic results and fundamental methods.Avoiding excessive technical detail, the book is intended for the student who has completed the equivalent of a standard first-year graduate algebra course. Thus it is assumed that the reader is familiar with basic ring-theoretic and group-theoretic concepts. A chapter on algebraic preliminaries is included, as well as a fairly large bibliography of works which are either directly relevant to the text or offer supplementary material of interest.

  5. Superconductivity elementary topics

    Shrivastava, KN

    2000-01-01

    This book describes the elementary concepts of superconductivity and discusses the topics of flux-lattice melting, magnetization including the para-Meissner effect, microwave absorption, a.c. resistivity along with the London penetration depth, the Mössbauer effect, levitation, fractals and nuclear magnetic resonance. There are appendices covering superconducting compounds, the isotope effect, symmetries, the pseudogap, relativistic superconductivity, the Cherenkov effect and soft vortices. Also included is an appendix on the quantum Hall effect. In all of the chapters, the theoretical descrip

  6. Topical Treatment in Rhinology

    Anamaria Gocea

    2014-02-01

    Full Text Available Far from being exhaustive, this paper aims to review the most illustrative topical therapies in rhinology, to show their patterns of action and their most suggestive characteristics proven by clinical trials and meta-analyses as tools of evidence based medecine. We describe several therapeutic clases: decongestants, antihistaminics, anticholinergics, antibiotics, disinfectants, antimicotics, fitotherapeutics, vitamins, immunotherapy and compounds. Furthermore, the nose is increasingly being used for the delivery of other drugs, ranging from hormone replacement therapy and growth hormone to insulin and anti-migraine medication (sumatriptan. The ability to directly reach the neuronal tissue in the olfactory niche and hence the brain makes this a very attractive challenge.

  7. Topics on continua

    Macias, Sergio

    2005-01-01

    Specialized as it might be, continuum theory is one of the most intriguing areas in mathematics. However, despite being popular journal fare, few books have thoroughly explored this interesting aspect of topology. In Topics on Continua, Sergio Macías, one of the field's leading scholars, presents four of his favorite continuum topics: inverse limits, Jones's set function T, homogenous continua, and n-fold hyperspaces, and in doing so, presents the most complete set of theorems and proofs ever contained in a single topology volume. Many of the results presented have previously appeared only in research papers, and some appear here for the first time. After building the requisite background and exploring the inverse limits of continua, the discussions focus on Professor Jones''s set function T and continua for which T is continuous. An introduction to topological groups and group actions lead to a proof of Effros''s Theorem, followed by a presentation of two decomposition theorems. The author then offers an...

  8. Recombinant Baculovirus Isolation.

    King, Linda A; Hitchman, Richard; Possee, Robert D

    2016-01-01

    Although there are several different methods available of making recombinant baculovirus expression vectors (reviewed in Chapter 3 ), all require a stage in which insect cells are transfected with either the virus genome alone (Bac-to-Bac(®) or BaculoDirect™, Invitrogen) or virus genome and transfer vector. In the latter case, this allows the natural process of homologous recombination to transfer the foreign gene, under control of the polyhedrin or other baculovirus gene promoter, from the transfer vector to the virus genome to create the recombinant virus. Previously, many methods required a plaque-assay to separate parental and recombinant virus prior to amplification and use of the recombinant virus. Fortunately, this step is no longer required for most systems currently available. This chapter provides an overview of the historical development of increasingly more efficient systems for the isolation of recombinant baculoviruses (Chapter 3 provides a full account of the different systems and transfer vectors available). The practical details cover: transfection of insect cells with either virus DNA or virus DNA and plasmid transfer vector; a reliable plaque-assay method that can be used to separate recombinant virus from parental (nonrecombinant) virus where this is necessary; methods for the small-scale amplification of recombinant virus; and subsequent titration by plaque-assay or real-time polymerase chain reaction (PCR). Methods unique to the Bac-to-Bac(®) system are also covered and include the transformation of bacterial cells and isolation of bacmid DNA ready for transfection of insect cells. PMID:26820854

  9. The Expression of the Thrombin Receptors PAR-3 and PAR-4 is Downregulated in Pancreatic Cancer Cell Lines

    Claudia Rudroff

    2015-05-01

    Full Text Available Background: Patients with pancreatic cancer frequently suffer from thrombosis as a consequence of excess thrombin generation. In addition to its role in the plasmatic coagulation cascade, thrombin induces numerous cellular effects by activating a unique group of G-protein-coupled receptors on the cell membrane, the proteinase-activated receptors (PARs. At present, PAR-1, PAR-3 and PAR-4 are known to be activated by thrombin. We previously demonstrated a putative role for PAR-1 in pancreatic cancer progression, but little is known about the physiological and pathophysiological roles of PAR-3 and PAR-4. In the present study, we examined the expression patterns of PAR-3 and PAR-4 in pancreatic tissue and pancreatic cancer cells. Methods: Tissue samples from three patients with pancreatic adenocarcinoma and six human pancreatic carcinoma cell lines were examined. Gene expression was analysed by RT-PCR and quantified by HPLC. Protein expression was determined by Western blot analysis. Data analysis was performed using ANOVA in SPSS. Results and Conclusion: In contrast to PAR-1, both PAR-3 and PAR-4 were expressed in healthy pancreases but downregulated in pancreatic cancer. The contrasting expression patterns of PAR-3 and PAR-4 compared with PAR-1 indicate that the mechanism that regulates the cellular effects of thrombin on tumor progression remains to be fully elucidated.

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

    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

  11. Effect of the immobilisation of DNA aptamers on the detection of thrombin by means of surface plasmon resonance

    Hianik, T.; Ostatná, V.; Vaisocherová, Hana; Homola, Jiří

    2008-01-01

    Roč. 391, č. 5 (2008), s. 1861-1869. ISSN 1618-2642 R&D Projects: GA AV ČR KAN200670701 Institutional research plan: CEZ:AV0Z20670512 Keywords : DNA aptamer * thrombin * dendrimers Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.328, year: 2008

  12. Topical Acne Treatments and Pregnancy

    Topical Acne Treatments and Pregnancy In every pregnancy, a woman starts out with a 3-5% chance of having ... This sheet talks about whether exposure to topical acne treatments may increase the risk for birth defects ...

  13. Symbiosis: Rich, Exciting, Neglected Topic

    Rowland, Jane Thomas

    1974-01-01

    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)

  14. Topical tretinoin in acanthosis nigricans

    Lahiri Koushik

    1996-01-01

    Full Text Available Efficacy of topical tretinoin was assessed in 30 cases of idiopathic acanthosis nigricans which were recalcitrant to conventional modalities of treatment. Topical tretinoin once at night application was found to be very effective both clinically and histologically.

  15. Topical tretinoin in acanthosis nigricans

    Lahiri Koushik; Malakar Subrata

    1996-01-01

    Efficacy of topical tretinoin was assessed in 30 cases of idiopathic acanthosis nigricans which were recalcitrant to conventional modalities of treatment. Topical tretinoin once at night application was found to be very effective both clinically and histologically.

  16. Topics in orbit equivalence

    Kechris, Alexander S

    2004-01-01

    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.

  17. Topics in atomic physics

    Burkhardt, Charles E

    2006-01-01

    The study of atomic physics propelled us into the quantum age in the early twentieth century and carried us into the twenty-first century with a wealth of new and, in some cases, unexplained phenomena. Topics in Atomic Physics provides a foundation for students to begin research in modern atomic physics. It can also serve as a reference because it contains material that is not easily located in other sources. A distinguishing feature is the thorough exposition of the quantum mechanical hydrogen atom using both the traditional formulation and an alternative treatment not usually found in textbooks. The alternative treatment exploits the preeminent nature of the pure Coulomb potential and places the Lenz vector operator on an equal footing with other operators corresponding to classically conserved quantities. A number of difficult to find proofs and derivations are included as is development of operator formalism that permits facile solution of the Stark effect in hydrogen. Discussion of the classical hydrogen...

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

    Fang Lanyun [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Ningbo Municipal Center for Disease Control and Prevention, Ningbo 315010, Zhejiang (China); Lue Zhaozi [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin (China); Wei Hui [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Wang Erkang [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, Jilin (China)], E-mail: ekwang@ciac.jl.cn

    2008-10-17

    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 {beta}- and {gamma}-thrombins had negligible response, which indicated a high specificity of {alpha}-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.

  19. Effect of Locked-Nucleic Acid on a Biologically Active G-Quadruplex. A Structure-Activity Relationship of the Thrombin Aptamer

    Michael B. Jarstfer

    2008-03-01

    Full Text Available Here we tested the ability to augment the biological activity of the thrombin aptamer, d(GGTTGGTGTGGTTGG, by using locked nucleic acid (LNA to influence its G-quadruplex structure. Compared to un-substituted control aptamer, LNA-containing aptamers displayed varying degrees of thrombin inhibition. Aptamers with LNA substituted in either positions G5, T7, or G8 showed decreased thrombin inhibition, whereas LNA at position G2 displayed activity comparable to un-substituted control aptamer. Interestingly, the thermal stability of the substituted aptamers does not correlate to activity – the more stable aptamers with LNA in position G5, T7, or G8 showed the least thrombin inhibition, while a less stable aptamer with LNA at G2 was as active as the un-substituted aptamer. These results suggest that LNA substitution at sites G5, T7, and G8 directly perturbs aptamer-thrombin affinity. This further implies that for the thrombin aptamer, activity is not dictated solely by the stability of the G-quadruplex structure, but by specific interactions between the central TGT loop and thrombin and that LNA can be tolerated in a biologically active nucleic acid structure albeit in a position dependent fashion.

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

    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

  1. Ultrasensitive electrochemical aptasensor for the detection of thrombin based on dual signal amplification strategy of Au@GS and DNA-CoPd NPs conjugates.

    Wang, Yaoguang; Zhang, Yong; Yan, Tao; Fan, Dawei; Du, Bin; Ma, Hongmin; Wei, Qin

    2016-06-15

    In this work, an ultrasensitive electrochemical aptasensor for the detection of thrombin was developed based on Au nanoparticles decorated graphene sheet (Au@GS) and CoPd binary nanoparticles (CoPd NPs). A sulfydryl-labeled thrombin capture probe (Apt1) and a biotin-labeled thrombin reporter probe (Apt2) were designed to achieve a sandwich-type strategy. Au@GS was used as a sensing platform for the facile immobilization of Apt1 through Au-S bond, forming a sensing interface for thrombin. The specific recognition of thrombin induced the attachment of Apt2-CoPd NPs to the electrode. The labeled CoPd NPs showed good catalytic properties toward the reduction of H2O2, resulting in an amperometric signal. The amperometric response was correlated to the thrombin concentration in sample solutions. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirmed the successful fabrication of the aptasensor. A linear response to thrombin in the range of 0.01-2.00ngmL(-1) with a low detection limit (5pgmL(-1)) was achieved. The proposed aptasensor showed good selectivity, good reproducibility and acceptable stability. This proposed strategy may find many potential applications in the detection of other biomolecules. PMID:26908183

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

    Oberdisse, E.; Lapetina, E.G.

    1987-05-14

    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.

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

    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

  4. The Polylingual Labeled Topic Model

    Posch, Lisa; Bleier, Arnim; Schaer, Philipp; Strohmaier, Markus

    2015-01-01

    In this paper, we present the Polylingual Labeled Topic Model, a model which combines the characteristics of the existing Polylingual Topic Model and Labeled LDA. The model accounts for multiple languages with separate topic distributions for each language while restricting the permitted topics of a document to a set of predefined labels. We explore the properties of the model in a two-language setting on a dataset from the social science domain. Our experiments show that our model outperform...

  5. 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

    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. 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. 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 10mm, 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. 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

  6. 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

    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)

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

    Duan, Ruixue; Zhou, Xiaoming

    2012-03-01

    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.

  8. Thrombin-induced TGF-β1 pathway: a cause of communicating hydrocephalus post subarachnoid hemorrhage.

    Li, Tong; Zhang, Peng; Yuan, Bin; Zhao, Dongliang; Chen, Yueqin; Zhang, Xinzhong

    2013-03-01

    The mechanism of communicating hydrocephalus after subarachnoid hemorrhage (SAH) remains unclear. Revealing a signaling cascade may provide significant insights into the molecular etiology of the accumulation of cerebrospinal fluid (CSF) in cerebral compartments during SAH. To investigate the mechanism of the communicating hydrocephalus following SAH, we infused CSF with thrombin (TH), resulting in proinflammatory and proliferative responses in rat meninges of SAH. The effect of TH could be completely blocked by a transforming growth factor β1 (TGF-β1) inhibitor, SB-431542, suggesting that TH-stimulated proliferation of meninges is through the TGF-β1 signaling pathway. The cascade of TGF β1-Smad3 was significantly upregulated by TH, which, in turn, stimulated the proliferation of subarachnoid meninges. TH-induced overexpression of TGF-β1 and activation of its downstream factors might be a mechanism of communicating hydrocephalus after SAH. PMID:23338707

  9. Aptamer-directed lanthanide chelate self-assembly for rapid thrombin detection.

    Pkkil, Henna; Blom, Sami; Kopra, Kari; Soukka, Tero

    2013-09-01

    We report a sensitive assay method for homogeneous thrombin detection. The method is based on lanthanide chelate complementation, where the luminescent complex is split into two separate label moieties, which are intrinsically non-luminescent. A luminescent mixed chelate complex is formed only when the label moieties are brought into close proximity directed by two separate binding events of aptamers to the analyte. This results in high specificity in signal generation while time-resolved fluorescence detection eliminates the short lifetime autofluorescence, which is inherent to many homogeneous assays and limits their applicability. The developed method is also very rapid as the maximum signal is obtained in just five minutes. Lanthanide chelate complementation can be applied for the detection of other proteins when two binders recognizing separate epitopes of the analyte are available. PMID:23807946

  10. Thrombin induces Egr-1 expression in fibroblasts involving elevation of the intracellular Ca2+ concentration, phosphorylation of ERK and activation of ternary complex factor

    Thiel Gerald

    2009-05-01

    Full Text Available Abstract Background The serine protease thrombin catalyzes fibrin clot formation by converting fibrinogen into fibrin. Additionally, thrombin stimulation leads to an activation of stimulus-responsive transcription factors in different cell types, indicating that the gene expression pattern is changed in thrombin-stimulated cells. The objective of this study was to analyze the signaling cascade leading to the expression of the zinc finger transcription factor Egr-1 in thrombin-stimulated lung fibroblasts. Results Stimulation of 39M1-81 fibroblasts with thrombin induced a robust and transient biosynthesis of Egr-1. Reporter gene analysis revealed that the newly synthesized Egr-1 was biologically active. The signaling cascade connecting thrombin stimulation with Egr-1 gene expression required elevated levels of cytosolic Ca2+, the activation of diacylgycerol-dependent protein kinase C isoenzymes, and the activation of extracellular signal-regulated protein kinase (ERK. Stimulation of the cells with thrombin triggered the phosphorylation of the transcription factor Elk-1. Expression of a dominant-negative mutant of Elk-1 completely prevented Egr-1 expression in stimulated 39M1-81 cells, indicating that Elk-1 or related ternary complex factors connect the intracellular signaling cascade elicited by activation of protease-activated receptors with transcription of the Egr-1 gene. Lentiviral-mediated expression of MAP kinase phosphatase-1, a dual-specific phosphatase that dephosphorylates and inactivates ERK in the nucleus, prevented Elk-1 phosphorylation and Egr-1 biosynthesis in thrombin stimulated 39M1-81 cells, confirming the importance of nuclear ERK and Elk-1 for the upregulation of Egr-1 expression in thrombin-stimulated lung fibroblasts. 39M1-81 cells additionally express M1 muscarinic acetylcholine receptors. A comparison between the signaling cascades induced by thrombin or carbachol showed no differences, except that signal transduction via M1 muscarinic acetylcholine receptors required the transactivation of the EGF receptor, while thrombin signaling did not. Conclusion This study shows that stimulus-transcription coupling in thrombin-treated lung fibroblasts relies on the elevation of the intracellular Ca2+-concentration and the activation of PKC and ERK. In the nucleus, ternary complex factors function as key proteins linking the intracellular signaling cascade with enhanced transcription of the Egr-1 gene. This study further shows that the dominant-negative Elk-1 mutant is a valuable tool to study Elk-1-mediated gene transcription.

  11. Resolution of radiolabeled molecular species of phospholipid in human platelets: effect of thrombin

    Resolution of individual molecular species of human platelet 1,2-diradyl-sn-glycero-3-phosphocholines and 1,2-diradyl-sn-glycero-3-phosphoethanolamines by reverse phase high pressure liquid chromatography (HPLC) allowed a thorough analysis of those phospholipids labeled with [3H]arachidonic acid. Approximately 54% and 16% of the total incorporated radiolabel was found in choline glycerophospholipids and ethanolamine glycerophospholipids, respectively, with ca. 90% of this being found in the 1,2-diacyl molecular species. Eighty percent of [3H]-arachidonic acid incorporated into 1-acyl-2-arachidonoyl-sn-glycero-3-phosphocholine in resting platelets was equally distributed between 1-palmitoyl-2-arachidonoyl and 1-stearoyl-2-arachidonoyl-sn-glycero-3-phosphocholine, while 70% of the radiolabel in 1-acyl-2-arachidonoyl-sn-glycero-3-phosphoethanolamine was found in 1-stearoyl-2-arachidonoyl-sn-glycero-3-phosphoethanolamine. Thrombin stimulation (5 U/ml for 5 min) resulted in deacylation of all 1-acyl-2-[3H]arachidonoyl molecular species of 1-acyl-2-arachidonoyl-sn-glycero-3-phosphocholine and 1-acyl-2-arachidonoyl-sn-glycero-3-ethanolamine. There was also a slight increase in 1-O-alkyl-2-[3H]arachidonoyl-sn-glycero-3-phosphocholine and a significant increase in 1-O-alk-1'-enyl-2-[3H]arachidonoyl-sn-glycero-3-phosphoethanolamine molecular species of over 300%. Thus, HPLC methodology indicates that arachidonoyl-containing molecular species of phosphatidylcholine and phosphatidylethanolamine are the major source of arachidonic acid in thrombin-stimulated human platelets, while certain ether phospholipid molecular species become enriched in arachidonate

  12. Regulation of Meiotic Recombination

    Gregory p. Copenhaver

    2011-11-09

    Meiotic recombination results in the heritable rearrangement of DNA, primarily through reciprocal exchange between homologous chromosome or gene conversion. In plants these events are critical for ensuring proper chromosome segregation, facilitating DNA repair and providing a basis for genetic diversity. Understanding this fundamental biological mechanism will directly facilitate trait mapping, conventional plant breeding, and development of genetic engineering techniques that will help support the responsible production and conversion of renewable resources for fuels, chemicals, and the conservation of energy (1-3). Substantial progress has been made in understanding the basal recombination machinery, much of which is conserved in organisms as diverse as yeast, plants and mammals (4, 5). Significantly less is known about the factors that regulate how often and where that basal machinery acts on higher eukaryotic chromosomes. One important mechanism for regulating the frequency and distribution of meiotic recombination is crossover interference - or the ability of one recombination event to influence nearby events. The MUS81 gene is thought to play an important role in regulating the influence of interference on crossing over. The immediate goals of this project are to use reverse genetics to identify mutants in two putative MUS81 homologs in the model plant Arabidopsis thaliana, characterize those mutants and initiate a novel forward genetic screen for additional regulators of meiotic recombination. The long-term goal of the project is to understand how meiotic recombination is regulated in higher eukaryotes with an emphasis on the molecular basis of crossover interference. The ability to monitor recombination in all four meiotic products (tetrad analysis) has been a powerful tool in the arsenal of yeast geneticists. Previously, the qrt mutant of Arabidopsis, which causes the four pollen products of male meiosis to remain attached, was developed as a facile system for assaying recombination using tetrad analysis in a higher eukaryotic system (6). This system enabled the measurement of the frequency and distribution of recombination events at a genome wide level in wild type Arabidopsis (7), construction of genetic linkage maps which include positions for each centromere (8), and modeling of the strength and pattern of interference (9). This proposal extends the use of tetrad analysis in Arabidopsis by using it as the basis for assessing the phenotypes of mutants in genes important for recombination and the regulation of crossover interference and performing a novel genetic screen. In addition to broadening our knowledge of a classic genetic problem - the regulation of recombination by crossover interference - this proposal also provides broader impact by: generating pedagogical tools for use in hands-on classroom experience with genetics, building interdisciplinary collegial partnerships, and creating a platform for participation by junior scientists from underrepresented groups. There are three specific aims: (1) Isolate mutants in Arabidopsis MUS81 homologs using T-DNA and TILLING (2) Characterize recombination levels and interference in mus81 mutants (3) Execute a novel genetic screen, based on tetrad analysis, for genes that regulate meiotic recombination

  13. Advanced verification topics

    Bhattacharya, Bishnupriya; Hall, Gary; Heaton, Nick; Kashai, Yaron; Khan Neyaz; Kirshenbaum, Zeev; Shneydor, Efrat

    2011-01-01

    The Accellera Universal Verification Methodology (UVM) standard is architected to scale, but verification is growing and in more than just the digital design dimension. It is growing in the SoC dimension to include low-power and mixed-signal and the system integration dimension to include multi-language support and acceleration. These items and others all contribute to the quality of the SOC so the Metric-Driven Verification (MDV) methodology is needed to unify it all into a coherent verification plan. This book is for verification engineers and managers familiar with the UVM and the benefits it brings to digital verification but who also need to tackle specialized tasks. It is also written for the SoC project manager that is tasked with building an efficient worldwide team. While the task continues to become more complex, Advanced Verification Topics describes methodologies outside of the Accellera UVM standard, but that build on it, to provide a way for SoC teams to stay productive and profitable.

  14. Topics in statistical mechanics

    This thesis deals with four independent topics in statistical mechanics: (1) the dimer problem is solved exactly for a hexagonal lattice with general boundary using a known generating function from the theory of partitions. It is shown that the leading term in the entropy depends on the shape of the boundary; (2) continuum models of percolation and self-avoiding walks are introduced with the property that their series expansions are sums over linear graphs with intrinsic combinatorial weights and explicit dimension dependence; (3) a constrained SOS model is used to describe the edge of a simple cubic crystal. Low and high temperature results are derived as well as the detailed behavior near the crystal facet; (4) the microscopic model of the lambda-transition involving atomic permutation cycles is reexamined. In particular, a new derivation of the two-component field theory model of the critical behavior is presented. Results for a lattice model originally proposed by Kikuchi are extended with a high temperature series expansion and Monte Carlo simulation. 30 references

  15. Superconcentration and related topics

    Chatterjee, Sourav

    2014-01-01

    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...

  16. Topics in inflationary cosmology

    This thesis examines several topics in the theory of inflationary cosmology. It first proves the existence of Hawking Radiation during the slow-rolling period of a new inflationary universe. It then derives and somewhat extends Bardeen's gauge invariant formalism for calculating the growth of linear gravitational perturbations in a Friedmann-Robertson-Walker cosmological background. This formalism is then applied, first to several new inflationary universe models all of which show a Zel'dovich spectrum of fluctuations, but with amplitude sigma(1004) above observational limits. The general formalism is next applied to models that exhibit primordial inflation. Fluctuations in these models also exhibit a Zel'dovich spectrum here with an acceptable amplitude. Finally the thesis presents the results of new, numerical calculations. A classical, (2 + 1) dimensional computer model is developed that includes a Higgs field (which drives inflation) along with enough auxiliary fields to generate dynamically not only a thermal bath, but also the fluctuations that naturally accompany that bath. The thesis ends with a discussion of future prospects

  17. Topics in statistical mechanics

    Elser, V.

    1984-05-01

    This thesis deals with four independent topics in statistical mechanics: (1) the dimer problem is solved exactly for a hexagonal lattice with general boundary using a known generating function from the theory of partitions. It is shown that the leading term in the entropy depends on the shape of the boundary; (2) continuum models of percolation and self-avoiding walks are introduced with the property that their series expansions are sums over linear graphs with intrinsic combinatorial weights and explicit dimension dependence; (3) a constrained SOS model is used to describe the edge of a simple cubic crystal. Low and high temperature results are derived as well as the detailed behavior near the crystal facet; (4) the microscopic model of the lambda-transition involving atomic permutation cycles is reexamined. In particular, a new derivation of the two-component field theory model of the critical behavior is presented. Results for a lattice model originally proposed by Kikuchi are extended with a high temperature series expansion and Monte Carlo simulation. 30 references.

  18. Recombinant expression and affinity purification of snake venom gland parvalbumin in Escherichia coli.

    Jia, Ying; Pérez, John C

    2009-07-01

    Parvalbumins (PV) are small, acidic, water soluble and calcium-binding proteins generally present in muscular and nervous tissues. In the present study, we identified and characterized a cDNA clone encoding PV, named AplPV, from a snake (Agkistrodon piscivorus leucostoma) venom gland cDNA library. AplPV belongs to EF-hand proteins with six alpha-helices constituting three EF-hand domains. The deduced amino acid sequence of AplPV is 91% and 68% identical to the previously characterized PVs of Boa constrictor and Cyprinus carpio, respectively. The full-length cDNA was subcloned into the expression vector pGEX and transformed into Escherichia coli (E.coli) to produce recombinant protein. The bacterially expressed GST-AplPV fusion protein was highly expressed, and effectively purified by Glutathione-Sepharose affinity chromatography. A high concentration of thrombin protease specifically cleaved and removed the GST tag from fusion protein, and further purified by Benzamidine column for removal of thrombin protease. As a result, the 12 kDa AplPV recombinant protein alone was purified. To investigate the tissue-specific biological occurrence of AplPV, a polyclonal antibody (anti-AplPV-antibody) was raised against GST-AplPV fusion protein in rabbit. Western blot analysis revealed that immunoreactive bands were exhibited in both recombinant protein and samples of venom glands, but not in any crude venom. This specific occurrence indicates a specialized function of AplPV in snake venom glands. PMID:19275943

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

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

    2013-01-01

    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

  20. Electrochemical and circular dichroism spectroscopic evidence of two types of interaction between [Ru(NH3)(6)](3+) and an elongated thrombin binding aptamer G-quadruplex

    De Rache, A.; Kejnovská, Iva; Buess-Herman, C.; Doneux, T.

    2015-01-01

    Roč. 179, OCT 2015 (2015), s. 84-92. ISSN 0013-4686 Institutional support: RVO:68081707 Keywords : Biosensors * Thrombin binding aptamer * Hexaammineruthenium Subject RIV: BO - Biophysics Impact factor: 4.504, year: 2014

  1. 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

    Johansson, Per Ingemar; Svendsen, M.S.; Salado, J.; Bochsen, L.; Kristensen, Annemarie Thuri

    2008-01-01

    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, ...

  2. Dielectronic recombination at nebular temperatures

    Rate coefficients for dielectronic recombination via low-lying resonance states are calculated for the recombined ions C+, C2+, N2+, N3+ and O4+ at the temperatures and densities appropriate to planetary nebulae. The total dielectronic recombination coefficients obtained are substantially larger than the corresponding radiative recombination coefficients, calculated neglecting resonances, and differ considerably from the dielectronic recombination coefficients generally in use. Effective recombination coefficients are given for spectrum lines that are formed during the cascade process. Some of these lines have been observed in IUE spectra of planetary nebulae. (author)

  3. Activation of human prothrombin by a procoagulant fraction from the venom of Echis carinatus. Identification of a high molecular weight intermediate with thrombin activity.

    Franza, B R; Aronson, D L; Finlayson, J S

    1975-09-10

    In the presence of a procoagulant fraction (Echis carinatus procoagulant) isolated from the venom of the saw-scaled viper Echis carinatus sochureki, purified human prothrombin (P1) is completely converted to thrombin. The first step is the removal of an NH2-terminal peptide (F1) representing approximately one-third of the prothrombin molecule. The remaining peptide (P2) is then cleaved by the action of E.c. procoagulant to yield a two-chain, disulfide-bridged protein (P'2) which has the same molecular weight as P2. P'2 has enzymic (thrombin) activity, as evidence by incorporation of radiolabeled diisopropylphosphate into its heavy chain (TB), hydrolysis of p-toluenesulfonylarginine methyl ester, and clotting of fibrinogen. Relative to thrombin, its esterolytic activity greatly exceeds its clot-promoting activity. Examination of the polypeptide chains obtained by reducing P'2 has shown that its larger chain (TB) is indistinguishable from the heavy chain of thrombin. Its other chain (F2TA) consists of the light chain (TA) of thrombin bound by peptide linkage to the protion of the prothrombin molecule which had been adjacent to F1. Removal of this portion (F2) is catalyzed by thrombin (and, evidently, by P'2), but not by the E.c. procoagulant. When F2 is removed from P'2, the remaining two-chian protein is indistinguishable from thrombin by any of the criteria applied--molecular weight, subunit chain composition, or enzymic activity. Polyacrylamide gel electrophoresis was carried out in sodium dodecyl sulfate before and after disulfide reduction of samples generated in the presence and in the absence of diisopropylphosphorofluoridate, which inhibits thrombin but not the E.c. procoagulant. Such experiments showed that thrombin (and probably P'2), as well as E.c. procoagulant, catalyzes the release of F1. Furthermore, thrombin brings about the cleavage of F1 to yield a two-chain, disulfidebridged protein (F'1). These observations, particularly those made in the course of characterizine P'2, have led to the conclusion that cleavage of the peptide bond connecting the TA and TB portions of the prothrombin molecule (or its derivatives) produces a serine active center and, hence, a molecule possessing thrombin activity. This cleavage is catalyzed by the E.c. procoagulant but not by thrombon itself. PMID:1158898

  4. An Automatic Topic Identification Algorithm

    Hossein S. Baghdadi

    2011-01-01

    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.

  5. Topic Maps :a bibliometric study

    Anyi, Kevin Wan Utap

    2012-01-01

    Topic Maps is an international standard (ISO/IEC 13250) to describe and encode knowledge structures and associating them with relevant information resources. This thesis seeks to investigate what has been written about Topic Maps from year 2000 to 2011, as well as finding out the research and publication trend in Topic Maps. This study was based on quantitative methodology, which was bibliometric analysis. The data was collected from Scopus and Web of Knowledge databases. Search keywords used...

  6. Topical corticosteroid addiction and phobia

    Aparajita Ghosh; Sujata Sengupta; Arijit Coondoo; Amlan Kusum Jana

    2014-01-01

    Corticosteroids, one of the most widely prescribed topical drugs, have been used for about six decades till date. However, rampant misuse and abuse down the years has given the drug a bad name. Topical steroid abuse may lead to two major problems which lie at the opposing ends of the psychosomatic spectrum. Topical steroid addiction, a phenomenon that came to be recognized about a decade after the introduction of the molecule is manifested as psychological distress and rebound phenomenon on s...

  7. Scaling up Dynamic Topic Models

    Bhadury, Arnab; Chen, Jianfei; Zhu, Jun; Liu, Shixia

    2016-01-01

    Dynamic topic models (DTMs) are very effective in discovering topics and capturing their evolution trends in time series data. To do posterior inference of DTMs, existing methods are all batch algorithms that scan the full dataset before each update of the model and make inexact variational approximations with mean-field assumptions. Due to a lack of a more scalable inference algorithm, despite the usefulness, DTMs have not captured large topic dynamics. This paper fills this research void, a...

  8. Topic selection in industry experiments

    Misirli, Ayse Tosun; Erdogmus, Hakan; Juristo Juzgado, Natalia; Dieste Tubio, Oscar

    2014-01-01

    This paper shares our experience with initial negotiation and topic elicitation process for conducting industry experiments in six software development organizations in Finland. The process involved interaction with company representatives in the form of both multiple group discussions and separate face-to-face meetings. Fitness criteria developed by researchers were applied to the list of generated topics to decide on a common topic. The challenges we faced include diversity of proposed topi...

  9. Hot topic [editorial

    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.)

  10. Dual-colored graphene quantum dots-labeled nanoprobes/graphene oxide: functional carbon materials for respective and simultaneous detection of DNA and thrombin

    Convenient and simultaneous detection of multiple biomarkers such as DNA and proteins with biocompatible materials and good analytical performance still remains a challenge. Herein, we report the respective and simultaneous detection of DNA and bovine α-thrombin (thrombin) entirely based on biocompatible carbon materials through a specially designed fluorescence on-off-on process. Colorful fluorescence, high emission efficiency, good photostability and excellent compatibility enables graphene quantum dots (GQDs) as the best choice for fluorophores in bioprobes, and thus two-colored GQDs as labeling fluorophores were chemically bonded with specific oligonucleotide sequence and aptamer to prepare two probes targeting the DNA and thrombin, respectively. Each probe can be assembled on the graphene oxide (GO) platform spontaneously by π–π stacking and electrostatic attraction; as a result, fast electron transfer in the assembly efficiently quenches the fluorescence of probe. The presence of DNA or thrombin can trigger the self-recognition between capturing a nucleotide sequence and its target DNA or between thrombin and its aptamer due to their specific hybridization and duplex DNA structures or the formation of apatamer–substrate complex, which is taken advantage of in order to achieve a separate quantitative analysis of DNA and thrombin. A dual-functional biosensor for simultaneous detection of DNA and thrombin was also constructed by self-assembly of two probes with distinct colors and GO platform, and was further evaluated with the presence of various concentrations of DNA and thrombin. Both biosensors serving as a general detection model for multiple species exhibit outstanding analytical performance, and are expected to be applied in vivo because of the excellent biocompatibility of their used materials. (paper)

  11. Inhibition of interleukin-12 expression by α-thrombin in human peripheral blood mononuclear cells: a potential mechanism for modulating Th1/Th2 responses

    Naldini, A.; Aarden, L.; Pucci, A; Bernini, C; Carraro, F

    2003-01-01

    In addition to its central role in blood coagulation and hemostasis, human α-thrombin is a powerful regulator of inflammatory responses and is known to affect cell-mediated immunity. Interleukin (IL)-12 is a strong promoter of the development of Th1-type lymphocytes and its downregulation implies a positive feedback mechanism for development of Th2 responses. We have previously shown that thrombin enhances the release of IL-6, a Th2-related cytokine, in human peripheral blood mononuclear cell...

  12. Dissociative recombination of NH+

    We have experimentally investigated dissociative recombination of NH+ with electrons using a merged ion and electron beam configuration in a storage ring. A fast counting and position sensitive imaging detector enabled us to perform fragment imaging measurements over relative electron-ion collision energies from 0 to 12 eV. The results show unprecedented details on product excitation and on the reaction dynamics.

  13. Continuous Time Dynamic Topic Models

    Wang, Chong; Blei, David; Heckerman, David

    2012-01-01

    In this paper, we develop the continuous time dynamic topic model (cDTM). The cDTM is a dynamic topic model that uses Brownian motion to model the latent topics through a sequential collection of documents, where a "topic" is a pattern of word use that we expect to evolve over the course of the collection. We derive an efficient variational approximate inference algorithm that takes advantage of the sparsity of observations in text, a property that lets us easily handle many time points. In c...

  14. Recent Developments in Dissociative Recombination

    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)

  15. Evidence supporting the use of recombinant activated factor VII in congenital bleeding disorders

    Pär I Johansson

    2010-06-01

    Full Text Available Pär I Johansson, Sisse R OstrowskiCapital Region Blood Bank, Section for Transfusion Medicine, Rigshospitalet, University of Copenhagen, Copenhagen, DenmarkBackground: Recombinant activated factor VII (rFVIIa, NovoSeven® was introduced in 1996 for the treatment of hemophilic patients with antibodies against coagulation factor VIII or IX.Objective: To review the evidence supporting the use of rFVIIa for the treatment of patients with congenital bleeding disorders.Patients and methods: English-language databases were searched in September 2009 for reports of randomized controlled trials (RCTs evaluating the ability of rFVIIa to restore hemostasis in patients with congenital bleeding disorders.Results: Eight RCTs involving 256 hemophilic patients with antibodies against coagulation factors, also known as inhibitors, were identified. The evidence supporting the use of rFVIIa in these patients was weak with regard to dose, clinical setting, mode of administration, efficacy, and adverse events, given the limited sample size of each RCT and the heterogeneity of the studies.Conclusion: The authors suggest that rFVIIa therapy in hemophilic patients with inhibitors should be based on the individual’s ability to generate thrombin and form a clot, and not on the patient’s weight alone. Therefore, assays for thrombin generation, such as whole-blood thromboelastography, have the potential to significantly improve the treatment of these patients.Keywords: hemophilia, inhibitors, coagulation factor VIII, coagulation factor IX, rFVIIa, NovoSeven, FEIBA, hemostasis, RCT

  16. Spectroscopic and Electrochemical Detection of Thrombin/5'-SH or 3'-SH Aptamer Immobilized on (porous) Gold Substrates

    Park, Buem Jin; Sa, Young Seung; Kim, Yong Hwan; Kim, Young Hun [Kwangwoon University, Seoul (Korea, Republic of)

    2012-01-15

    Thrombin is a serine protease that catalyzes the conversion of soluble fibrinogen to insoluble fibrin, and thus induces physiological and pathological blood coagulation. Therefore, it is important to detect thrombin in blood serum for purposes of diagnosis. To achieve this goal, it has been suggested that a 15-mer aptamer strongly binds with thrombin to form a G-quartet structure of the aptamer. Generally, 5'-end thiol-functionalized aptamer has been used as an anti-thrombin binder. Herein, we evaluate the possibility of utilizing a 3'-SH aptasensor for thrombin detection using SPR spectroscopy, and compare the enhancement of the electrochemical signal of the thrombin-aptamer bound on a porous gold substrate. Although the two aptamers have similar configurations, in SPR analysis, the 3'-SH aptamer was a effective aptasensor as well as 5'-SH aptamer. Results from electrochemical analysis showed that the porous gold substrate acted as a good substrate for an aptasensor and demonstrated 5-fold enhancement of current change, as compared to gold thin film.

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

    Skov Madsen, P; Hokland, P; Hokland, M

    1987-01-01

    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...

  18. Exposure- response for biomarkers of anticoagulant effects by the oral direct thrombin inhibitor AZD0837 in patients with atrial fibrillation

    Lip, Gregory Y H; Rasmussen, Lars H; Olsson, S Bertil; Jensen, Eva; Hamrn, Bengt; Eriksson, Ulf G; Whlander, Karin

    2015-01-01

    ) analysis was performed and the effect of AZD0837 therapy on fibrin D-dimer levels was correlated to the PK exposure of AR-H067637, as well as the effect on thrombin generation measured ex vivo, to guide selection of the effective dose regimen for a confirmatory efficacy study in AF patients. PATIENTS AND...... METHODS: Blood samples were obtained from 601 AF patients randomized to receive 1 of 4 doses of AZD0837 (blinded treatment) or dose-adjusted vitamin K antagonists (VKA, open treatment) for 3-9?months. A pharmacodynamic model was developed to describe time course of the AR-H067637 exposure dependent...... effects and the effect of VKA on fibrin D-dimer. The concentration-effect relationship for thrombin generation measured ex vivo in venous plasma was also investigated. RESULTS: AZD0837 was rapidly bioconverted to AR-H067637, showing stable exposure with an estimated interindividual variability of 33% with...

  19. Investigations of the thrombin generation test for the measurement of factor VIII.

    McIntosh, J H

    2005-01-01

    Haemophilia A is a genetic bleeding disorder in which the plasma level of the clotting protein FVHI is reduced or absent Treatment of haemophilia is by replacement of the missing FVTII with FVIII concentrates made from human plasma, or by recombinant technology. The two widely used assays for FVIII measurement (one-stage APTT and chromogenic assay) have disagreements in potency of FVIII concentrates and in post-infusion plasma samples these discrepancies are largest for the recombinant produc...

  20. Aptamer-functionalized solid phase microextraction-liquid chromatography/tandem mass spectrometry for selective enrichment and determination of thrombin.

    Du, Fuyou; Alam, Md Nazmul; Pawliszyn, Janusz

    2014-10-01

    In this publication, a novel solid phase microextraction (SPME) coating functionalized with a DNA aptamer for selective enrichment of a low abundance protein from diluted human plasma is described. This approach is based on the covalent immobilization of an aptamer ligand on electrospun microfibers made with the hydrophilic polymer poly(acrylonitrile-co-maleic acid) (PANCMA) on stainless steel rods. A plasma protein, human ?-thrombin, was employed as a model protein for selective extraction by the developed Apt-SPME probe, and the detection was carried out with liquid chromatography/tandem mass spectrometry (LC-MS/MS). The SPME probe exhibited highly selective capture, good binding capacity, high stability and good repeatability for the extraction of thrombin. The protein selective probe was employed for direct extraction of thrombin from 20-fold diluted human plasma samples without any other purification. The Apt-SPME method coupled with LC-MS/MS provided a good linear dynamic range of 0.5-50 nM in diluted human plasma with a good correlation coefficient (R(2)=0.9923), and the detection limit of the proposed method was found to be 0.30 nM. Finally, the Apt-SPME coupled with LC-MS/MS method was successfully utilized for the determination of thrombin in clinical human plasma samples. One shortcoming of the method is its reduced efficiency in undiluted human plasma compared to the standard solution. Nevertheless, this new aptamer affinity-based SPME probe opens up the possibility of selective enrichment of a given targeted protein from complex sample either in vivo or ex vivo. PMID:25201271

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

    Nam Youngwon; Ji-Eun Kim; Hae Sook Lim; Kyou-Sup Han; Hyun Kyung Kim

    2013-01-01

    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...

  2. A brief exposure to tryptase or thrombin potentiates fibrocyte differentiation in the presence of serum or SAP

    White, Michael J. V.; Galvis-Carvajal, Elkin; Gomer, Richard H

    2014-01-01

    A key question in both wound healing and fibrosis is the trigger for the initial formation of scar tissue. To help form scar tissue, circulating monocytes enter the tissue and differentiate into fibroblast-like cells called fibrocytes, but fibrocyte differentiation is strongly inhibited by the plasma protein Serum Amyloid P (SAP), and healthy tissues contain very few fibrocytes. In wounds and fibrotic lesions, mast cells degranulate to release tryptase, and in early wounds thrombin mediates b...

  3. Anti-thrombin III, Protein C, and Protein S deficiency in acute coronary syndrome

    Dasnan Ismail

    2002-06-01

    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

  4. Hot topics for leadership development.

    Bleich, Michael R

    2015-02-01

    Three areas stand out from a health systems perspective that should be on the development agenda for all leaders. These topics include population health, predictive analytics, and supply chain management. Together, these topics address access, quality, and cost management. PMID:25633301

  5. Updated Topics in Healthcare Informatics

    Takeda, Hiroshi,

    2010-01-01

    This key note lecture introduces the role of IMIA, scope of healthcare informatics and some topics in healthcare informatics. Among updated topics, electronic patient record (EPR) and electronic health record (EHR) are featured. A new paradigm of clinical information systems, a document archiving and communication system (DACS) is also described and discussed.

  6. The application of a modified nucleotide in aptamer selection: novel thrombin aptamers containing 5-(1-pentynyl)-2'-deoxyuridine.

    Latham, J A; Johnson, R; Toole, J J

    1994-01-01

    Combinatorial libraries of nucleic acids are developing into novel sources for lead compounds in drug development. In order to diversify the pool of ss DNA sequences, we have used a modified nucleotide, 5-(1-pentynyl)-2'-deoxyuridine, in place of thymidine in a random nucleic acid library and screened this library against human thrombin. Previously, we described this screening method to identify a novel structural inhibitor (an aptamer) of the coagulation protease thrombin (Bock, L. et. al. (1992) Nature 355 564-566). Using the modified nucleic acid library, we have now isolated a second pool of thrombin inhibitors with strikingly different sequence composition compared to the selection using natural bases. This second class of aptamers is dependent on the presence of the modified nucleotide for protein binding and clotting inhibition. Our method represents a potential strategy to enhance the diversity of libraries for in vitro selection, and thereby increasing the utility of this technique in the identification of molecules with novel biochemical properties. Images PMID:7519769

  7. A sensitive electrochemical aptasensor based on water soluble CdSe quantum dots (QDs) for thrombin determination

    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 ?g mL-1 and from 14 to 31 ?g mL-1, respectively. The detection limit was 0.08 ?g mL-1 at 3?. 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.

  8. A sensitive electrochemical aptasensor based on water soluble CdSe quantum dots (QDs) for thrombin determination

    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

    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.

  9. Microfluidic Chip-Based Online Screening Coupled to Mass Spectrometry: Identification of Inhibitors of Thrombin and Factor Xa.

    Iyer, Janaki Krishnamoorthy; Otvos, Reka A; Kool, Jeroen; Kini, R Manjunatha

    2016-02-01

    Thrombin and factor Xa (FXa) are critical enzymes of the blood coagulation cascade and are excellent targets of anticoagulant agents. Natural sources present an array of anticoagulants that can be developed as antithrombotic drugs. High-resolution, online screening techniques have been developed for the identification of drug leads from complex mixtures. In this study, we have developed and optimized a microfluidic online screening technique coupled to nano-liquid chromatography (LC) and in parallel with a mass spectrometer for the identification of thrombin and FXa inhibitors in mixtures. Inhibitors eluting from the nano-LC were split postcolumn in a 1:1 ratio; half was fed into a mass spectrometer (where its mass is detected), and the other half was fed into a microfluidic chip (which acts as a microreactor for the online assays). With our platform, thrombin and FXa inhibitors were detected in the assay in parallel with their mass identification. These methods are suitable for the identification of inhibitors from sample amounts as low as sub-microliter volumes. PMID:26323281

  10. Aptamer functionalized hydrophilic polymer monolith with gold nanoparticles modification for the sensitive detection of human α-thrombin.

    Chen, Yuanbo; Deng, Nan; Wu, Ci; Liang, Yu; Jiang, Bo; Yang, Kaiguang; Liang, Zhen; Zhang, Lihua; Zhang, Yukui

    2016-07-01

    Low abundant proteins of body fluids participate nearly all physiological processes and indicate various kinds of diseases. The development of specific enrichment techniques is the key to identify and quantify the low abundant proteins. Herein, a novel kind of aptamer functionalized hydrophilic polymer monolith was developed for the specific enrichment and detection of human α-thrombin from the human plasma. Human α-thrombin aptamer, with thiol group modified at the 5' terminal, was immobilized on the gold nanoparticles (AuNPs) modified poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate) monolithic column, with the binding capacity of 277.1μmol/L. Due to the hydrophilic poly(ethylene glycol) diacrylate) as the cross-linking monomer, the detection recovery of the aptamer-functionalized hydrophilic polymer monolithic column could reach to 92.6±5.2% (n=3) and the dynamic range could reach 0.5-300ng/μL (S/N>10) with on-line UV detection. Meanwhile, the column could run over 100 times, because the poly(glycidyl methacrylate-co-poly(ethylene glycol) diacrylate) stability structure and the AuNPs improved the stability of the matrix material. Furthermore, this column could even capture the target α-thrombin, which was spiked in 1000 folds of original human plasma. All these results demonstrated the great potential of the prepared aptamer functionalized hydrophilic polymer monolith for the recognition of the trace proteins in the biological samples. PMID:27154714

  11. Isolation and characterization of the thrombin-like enzyme from Cryptelytrops albolabris (white-lipped tree viper) venom.

    Tan, Nget Hong; Fung, Shin Yee; Yap, Yeannie Hui Yeng

    2012-01-01

    A thrombin-like enzyme (termed albolabrase) was isolated in purified form from the venom of Cryptelytrops albolabris (white-lipped tree viper) using high performance anion ion exchange and gel filtration chromatography. The molecular mass of albolabrase was 33.7 kDa as determined by SDS-PAGE and 35.8 kDa as determined by Superose gel filtration chromatography. The N-terminal sequence was determined to be VVGGDECNINE which is homologous to many snake venom thrombin-like enzymes. Albolabrase exhibits both arginine ester hydrolase and arginine amidase activities and the enzyme is fastidious towards tripeptide chromogenic anilide substrates. The fibrinogen clotting activity was optimum at 3mg/mL bovine fibrinogen, and showed distinct species differences in the following decreasing order: bovine fibrinogen>dog fibrinogen?human fibrinogen>goat fibrinogen. The enzyme failed to clot both rabbit and cat fibrinogens. Reversed-phase HPLC analysis on the breakdown products of fibrinogenolytic action of albolabrase indicated that the enzyme belongs to the AB class of snake venom thrombin-like enzyme. In the indirect ELISA, IgG anti-albolabrase reacted extensively with most crotalid venoms, except with Tropidolaemus wagleri and Calloselasma rhodostoma venoms. The double sandwich ELISA, however, showed that anti-albolabrase reacted strongly only with venoms from the Trimeresurus complex, and that the results support the proposed new taxonomy changes concerning the Trimeresurus complex. PMID:21983189

  12. Advancements in Topical Antifungal Vehicles.

    Kircik, Leon H

    2016-02-01

    The primary treatment for superficial fungal infections is antifungal topical formulations, and allylamines and azoles represent the two major classes of topical formulations that are used to treat these infections. The stratum corneum (SC) is composed of keratinocytes that are surrounded by a matrix of lipids. The efficacy of topically applied formulations depends on their ability to penetrate this lipid matrix, and the vehicle plays an integral role in the penetration of active molecule into skin. There are several challenges to formulating topical drugs, which include the biotransformation of the active molecules as they pass through the SC and the physical changes that occur to the vehicle itself when it is applied to the skin. This article will review current and emerging topical antifungal vehicles. J Drugs Dermatol. 2016;15(Suppl 2):s44-48. PMID:26885798

  13. Recombinant influenza vaccines.

    Sedova, E S; Shcherbinin, D N; Migunov, A I; Smirnov, Iu A; Logunov, D Iu; Shmarov, M M; Tsybalova, L M; Naroditskiĭ, B S; Kiselev, O I; Gintsburg, A L

    2012-10-01

    This review covers the problems encountered in the construction and production of new recombinant influenza vaccines. New approaches to the development of influenza vaccines are investigated; they include reverse genetics methods, production of virus-like particles, and DNA- and viral vector-based vaccines. Such approaches as the delivery of foreign genes by DNA- and viral vector-based vaccines can preserve the native structure of antigens. Adenoviral vectors are a promising gene-delivery platform for a variety of genetic vaccines. Adenoviruses can efficiently penetrate the human organism through mucosal epithelium, thus providing long-term antigen persistence and induction of the innate immune response. This review provides an overview of the practicability of the production of new recombinant influenza cross-protective vaccines on the basis of adenoviral vectors expressing hemagglutinin genes of different influenza strains. PMID:23346377

  14. Recombinant Human Enterovirus 71

    2004-01-01

    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.

  15. Relativistic dielectronic recombination theory

    Dielectronic recombination (DR) is an inverse Auger process in which a free electron is captured by a recombining ion to form a doubly excited autoionizing state. The subsequent decay of the autoionizing state to a stabilized bound state by emitting photons completes the recombination process. DR is an important recombination process for high temperature plasmas. It can affect the ionization balance and level kinetics of the hot plasmas. In addition, the dielectronic satellite lines observed in the emission spectra are frequently used as plasmas diagnostic tools. In the past decade, intense theoretical and experimental studies on the DR process have been carried out. Most of the earlier theoretical calculations on the DR rate coefficients were done either by using a term average approximation or in LS coupling without including the effects of relativity and configuration interaction. The early experimental investigations were concentrated on few times ionized low-Z ions. Recently, the development of electron beam ion trap (EBIT), electron beam ion source (EBIS) and heavy ion storage ring has become possible to produce very highly-charged heavy ions (e.g. U82+ and Xe53+)and to study the interaction between electrons and these ions. For highly-charged heavy ions, one excepts that the nonrelativistic method would be inadequate and a relativistic treatment is necessary. To meet this challenge we have developed a relativistic package based on the multiconfiguration Dirac-Fock method and have carried out systematic relativistic calculations of DR cross sections and rate coefficients and resonant transfer and excitation cross sections in ion-atom collisions. In this paper, we will briefly discuss the relativistic calculations of atomic structure and transition rates and will focus for attention on the effects of relativity and intermediate coupling on the DR cross sections and rate coefficients

  16. Hydrogen--oxygen recombiner

    An apparatus is disclosed for efficiently and safely recombining hydrogen and oxygen gas to form water vapor, the apparatus being particularly adapted for use with a nuclear reactor system in which potentially dangerous hydrogen gas, evolved within the containment vessel during certain postulated accident conditions, can be eliminated. Further, this apparatus also aids in the removal of certain radioactive contaminents from the gases in a containment vessel

  17. Intrachromosomal recombination in plants.

    Peterhans, A; Schlpmann, H; Basse, C; Paszkowski, J

    1990-01-01

    Molecular evidence for intrachromosomal recombination between closely linked DNA repeats within the plant genome is presented. The non-overlapping complementary deletion derivatives of the selectable neomycin phosphotransferase gene (nptII), when intact conferring kanamycin resistance, were inserted into the genome of Nicotiana tabacum. The functional marker gene was restored with frequencies between 10(-4) and 10(-6) per proliferating cell clone. Prolonged tissue culture prior to kanamycin s...

  18. Peptide affinity labels for thrombin and other trypsin-like proteases

    Shaw, Elliott N.; Kettner, Charles A.

    1982-03-09

    A peptide affinity label of the formula (I): ##STR1## wherein X is a radical capable of acting as a leaving group in a nucleophilic substitution reaction; A is an aromatic amino acid residue; B is H, or a C.sub.1 -C.sub.4 alkyl group, or aryl; Y is selected from the group consisting of hydrogen, aroyl, C.sub.1 -C.sub.6 acyl, and Q--(A)--.sub.n, wherein Q=hydrogen, aroyl, or C.sub.1 -C.sub.6 acyl, n=1-10, A is an amino acid residue selected from the aliphatic, hydroxy-containing, carboxylic acid group, and amide-thereof-containing, aromatic, sulfur-containing and imino-containing amino acids; and wherein J is selected from the group consisting of --CH.sub.2 --, --CH.sub.2 --CH.sub.2 --,--CH.sub.2 --CH.sub.2 --CH.sub.2 --, --CH.dbd.CH-- and --CH(OH)--CH.sub.2. The affinity label is useful for irreversibly inactivating thrombin and trypsin-like enzymes and may be used as a potential anticlotting agent.

  19. Thrombin and plasmin-like activities in the latices of Cryptostegia grandiflora and Plumeria rubra.

    Viana, Carolina A; Oliveira, Jefferson S; Freitas, Cleverson D T; Alencar, Nylane M N; Carvalho, Cristina P S; Nishi, Beatriz C; Ramos, Mrcio V

    2013-06-01

    Latex proteins have drawn attention because they have shown several pharmacological activities. Herein, the fibrin(ogen)olytic activity of Cryptostegia grandiflora (CgLP) and Plumeria rubra (PrLP) latices were evaluated and characterized. Ion-exchange chromatography separated CgLP in proteolytic (CgLP PI) and nonproteolytic proteins (CgLP PII). CgLP and CgLP PI hydrolyzed azocasein in a dose-dependent manner, whereas CgLP PII and PrLP showed negligible activities. CgLP and CgLP PI accelerated plasmatic clot formation and digested all fibrinogen chains in a time/dose-dependent manner, though in a nonspecific way. CgLP and CgLP PI did not fully hydrolyze the subunits of the fibrin clot since fibrin ?-chain showed resistance to proteolysis. No fibrinogenolytic activity was noticed after incubation of CgLP and CgLP PI with E-64. These results suggested that fibrinogenolytic and procoagulant activities of C. grandiflora were performed by cysteine proteases and confirm the activity of latex cysteine proteases as thrombin and plasmin-like proteins. PMID:23314383

  20. Two related thrombin-like enzymes present in Bothrops atrox venom

    Petretski J.H.

    2000-01-01

    Full Text Available This article describes the presence of two new forms of a thrombin-like enzyme, both with apparent molecular masses of 38 kDa, in Bothrops atrox venom. Both share the ability to cleave fibrinogen into fibrin and to digest casein. Both present identical Km on the substrate BApNA. Their N-terminal amino acid sequences are identical for 26 residues, sharing 80% homology with batroxobin and flavoxobin. Two groups of monoclonal antibodies (mAbs raised against the purified enzyme forms recognized different epitopes of the putative corresponding enzymes present in B. atrox crude venom. On Western blotting analysis of B. atrox crude venom, mAbs 5DB2C8, 5AA10 and 5CF11, but not mAbs 6CC5 and 6AD2-G5, revealed two or more protein bands ranging from 25 to 38 kDa. By immunoprecipitation assays, the 6AD2-G5 mAb was able to precipitate protein bands of 36-38 kDa from B. atrox, B. leucurus, B. pradoi, B. moojeni, B. jararaca and B. neuwiedii crude venoms. Fibrinogen-clotting activity was inhibited when the same venom specimens were pre-incubated with mAb 6AD2-G5, except for B. jararaca and B. neuwiedii.

  1. Unfolding mechanism of thrombin-binding aptamer revealed by molecular dynamics simulation and Markov State Model

    Zeng, Xiaojun; Zhang, Liyun; Xiao, Xiuchan; Jiang, Yuanyuan; Guo, Yanzhi; Yu, Xinyan; Pu, Xuemei; Li, Menglong

    2016-01-01

    Thrombin-binding aptamer (TBA) with the sequence 5′GGTTGGTGTGGTTGG3′ could fold into G-quadruplex, which correlates with functionally important genomic regionsis. However, unfolding mechanism involved in the structural stability of G-quadruplex has not been satisfactorily elucidated on experiments so far. Herein, we studied the unfolding pathway of TBA by a combination of molecular dynamics simulation (MD) and Markov State Model (MSM). Our results revealed that the unfolding of TBA is not a simple two-state process but proceeds along multiple pathways with multistate intermediates. One high flux confirms some observations from NMR experiment. Another high flux exhibits a different and simpler unfolding pathway with less intermediates. Two important intermediate states were identified. One is similar to the G-triplex reported in the folding of G-quadruplex, but lack of H-bonding between guanines in the upper plane. More importantly, another intermediate state acting as a connector to link the folding region and the unfolding one, was the first time identified, which exhibits higher population and stability than the G-triplex-like intermediate. These results will provide valuable information for extending our understanding the folding landscape of G-quadruplex formation. PMID:27045335

  2. DIRECT SMEAR VS CELL BLOCK (PLASMA- THROMBIN CLOT METHOD: DIAGNOSTIC VALUE IN SEROSAL CAVITIES FLUIDS CYTOLOGY

    P MAHZOUNI

    2000-03-01

    Full Text Available Introduction. To improve testing sensitivity, most laboratories use two or more preparation methods but in our laboratories only one method is used which is "direct smear". In this study we tried to evaluate the diagnostic value of cell block as adjunct to direct smear in the cytologic investigation of serosal cavities fluids. Methods. In a clinical trial study 62 specimens of serosal cavity fluids were investigated in AL-Zahrapathology laboratory (Get. 1998 to Get. 1999. Cytologic slides from each specimens were prepared in two methods: direct smear and cell block (plasma- thrombin clot method. Smears and cell blocks were studied separately by the same cytopathologist. The diagnosis were categorized as positive, negative, suspicious or unsatisfactory. Also, the time required for studing of each slides were noted. Findings. The findings indicated that there are discrepancy between direct smear and cell block methods in the number of "suspicious" cases. Also there is significant difference between the mean time needed for studing of direct smear and cell block. Conclusion. It is recommended that the remainer of each specimen should be kept in refrigerator in order to prepare cell blocks in suspicious cases of direct smear. This method facilitates making a more definite diagnosis and reducing the number of suspicious cases.

  3. Dielectronic recombination theory

    A theory now in wide use for the calculation of dielectronic recombination cross sections (?DR) and rate coefficients (?DR) was one introduced originally by Feshbach for nuclear physics applications, and then later adapted for atomic scattering problems by Hahn. In the following, we briefly review this theory in a very general form, which allows one to account for the effects of overlapping and interacting resonances, as well as continuum-continuum coupling. An extension of our notation will then also allow for the inclusion of the effects of direct radiative recombination, along with a treatment of the interference between radiative and dielectronic recombination. Other approaches to the calculation of ?DR have been described by Fano and by Seaton. We will not consider those theories here. Calculations of ?DR have progressed considerably over the last 25 years, since the early work of Burgess. Advances in the reliability of theoretical predictions have also been promoted recently b a variety of direct laboratory measurements of ?DR. While the measurements of ?DR for ?n ? 0 excitations have tended to agree very well with calculations, the case of ?n = 0 has been much problematic. However, by invoking a mechanism originally proposed by Jacobs, which takes into account the effect of stray electric fields on high Rydberg states (HRS) participating in the DR process, new calculations have improved the agreement between theory and experiment for these cases. Nevertheless, certain discrepancies still remain

  4. Evidence of recombination within human alpha-papillomavirus

    Carvajal-Rodríguez Antonio

    2007-03-01

    Full Text Available Abstract Background Human papillomavirus (HPV has a causal role in cervical cancer with almost half a million new cases occurring each year. Presence of the carcinogenic HPV is necessary for the development of the invasive carcinoma of the genital tract. Therefore, persistent infection with carcinogenic HPV causes virtually all cervical cancers. Some aspects of the molecular evolution of this virus, as the putative importance of recombination in its evolutionary history, are an opened current question. In addition, recombination could also be a significant issue nowadays since the frequency of co-infection with more than one HPV type is not a rare event and, thus, new recombinant types could be currently being generated. Results We have used human alpha-PV sequences from the public database at Los Alamos National Laboratory to report evidence that recombination may exist in this virus. A model-based population genetic approach was used to infer the recombination signal from the HPV DNA sequences grouped attending to phylogenetic and epidemiological information, as well as to clinical manifestations. Our results agree with recently published ones that use a different methodology to detect recombination associated to the gene L2. In addition, we have detected significant recombination signal in the genes E6, E7, L2 and L1 at different groups, and importantly within the high-risk type HPV16. The method used has recently been shown to be one of the most powerful and reliable procedures to detect the recombination signal. Conclusion We provide new support to the recent evidence of recombination in HPV. Additionally, we performed the recombination estimation assuming the best-fit model of nucleotide substitution and rate variation among sites, of the HPV DNA sequence sets. We found that the gene with recombination in most of the groups is L2 but the highest values were detected in L1 and E6. Gene E7 was recombinant only within the HPV16 type. The topic deserves further study because recombination is an important evolutionary mechanism that could have high impact both in pharmacogenomics (i.e. on the influence of genetic variation on the response to drugs and for vaccine development.

  5. Topical steroid-damaged skin

    Anil Abraham

    2014-01-01

    Full Text Available Topical steroids, commonly used for a wide range of skin disorders, are associated with side effects both systemic and cutaneous. This article aims at bringing awareness among practitioners, about the cutaneous side effects of easily available, over the counter, topical steroids. This makes it important for us as dermatologists to weigh the usefulness of topical steroids versus their side effects, and to make an informed decision regarding their use in each individual based on other factors such as age, site involved and type of skin disorder.

  6. Topics in lightwave transmission systems

    Li, Tingye

    1991-01-01

    Topics in Lightwave Transmission Systems is a second volume of a treatise on optical fiber communications that is devoted to the science, engineering, and application of information transmission via optical fibers. The first volume, published in 1985, dealt exclusively with fiber fabrication. The present volume contains topics that pertain to subsystems and systems. The book contains five chapters and begins with discussions of transmitters and receivers, which are basic to systems now operating in the field. Subsequent chapters cover topics relating to coherent systems: frequency and phase m

  7. Retinoic Acid Promotes Interleukin-4 Plasmid-Dimethylsulfoxide Topical Transdermal Delivery for Treatment of Psoriasis

    Chen, Zhong-Wen; Zhang, Yin-Bing; Chen, Xaing-Jun; Liu, Xiao; Wang, Zhen; Zhou, Xi-Kun; Qiu, Ji; Zhang, Nan-Nan; Teng, Xiu; MAO, YONG-QIU; Liu, Chang-Yong; Wei, Yu-quan; Li, Jiong

    2015-01-01

    Background Psoriasis is an autoimmune disease that is caused by a shift in the Th1/Th2 balance toward Th1-dominant immunity. It has been established as an effective treatment to counteract psoriasis by subcutaneous injection of recombinant interleukin (IL)-4, and IL-4 gene therapy by topical transdermal penetration has shown its antipsoriatic effect in mice. Retinoic acid (RA) and dimethylsulfoxide can increase the efficiency of gene transfection in the topical transdermal delivery system. Ob...

  8. HOT TOPICS IN FOOD MICROBIOLOGY

    Escherichia coli is a bacterium whose importance ranges from its role as a host for recombinant DNA manipulations to being one of the most well-recognized foodborne pathogens. Most E. coli strains are considered to be part of the normal microflora of the intestinal tract of humans and other warm-bl...

  9. Selected topics in nuclear structure

    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

  10. Erythromycin and Benzoyl Peroxide Topical

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

  11. Present topics of nuclear energy

    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)

  12. Topics on the FORM software

    These notes studies the compilation with FORM software as applied to high energy physics, covering the following topics: Command structures, statistics and numbers, Dirac matrices, optimization control, Gamma matrices, errors and polynomial substitution

  13. Iodine Absorption After Topical Administration

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

    1987-01-01

    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.

  14. Special topics in spectral distributions

    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

  15. Do scientists trace hot topics?

    Tian Wei; Menghui Li; Chensheng Wu; Xiao-Yong Yan; Ying Fan; Zengru Di; Jinshan Wu

    2013-01-01

    Do scientists follow hot topics in their scientific investigations? In this paper, by performing analysis to papers published in the American Physical Society (APS) Physical Review journals, it is found that papers are more likely to be attracted by hot fields, where the hotness of a field is measured by the number of papers belonging to the field. This indicates that scientists generally do follow hot topics. However, there are qualitative differences among scientists from various countries,...

  16. KEY TOPICS IN SPORTS MEDICINE

    Amir Ali Narvani; Panagiotis Thomas; Burce Lynn

    2006-01-01

    Key Topics in Sports Medicine is a single quick reference source for sports and exercise medicine. It presents the essential information from across relevant topic areas, and includes both the core and emerging issues in this rapidly developing field. It covers: 1) Sports injuries, rehabilitation and injury prevention, 2) Exercise physiology, fitness testing and training, 3) Drugs in sport, 4) Exercise and health promotion, 5) Sport and exercise for special and clinical populations, 6) The ps...

  17. Topics of Bioengineering in Wikipedia

    Vassia Atanassova

    2009-01-01

    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.

  18. Topics of Bioengineering in Wikipedia

    Vassia Atanassova

    2009-10-01

    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.

  19. Recombinant Collagenlike Proteins

    Fertala, Andzej

    2007-01-01

    A group of collagenlike recombinant proteins containing high densities of biologically active sites has been invented. The method used to express these proteins is similar to a method of expressing recombinant procollagens and collagens described in U. S. Patent 5,593,859, "Synthesis of human procollagens and collagens in recombinant DNA systems." Customized collagenous proteins are needed for biomedical applications. In particular, fibrillar collagens are attractive for production of matrices needed for tissue engineering and drug delivery. Prior to this invention, there was no way of producing customized collagenous proteins for these and other applications. Heretofore, collagenous proteins have been produced by use of such biological systems as yeasts, bacteria, and transgenic animals and plants. These products are normal collagens that can also be extracted from such sources as tendons, bones, and hides. These products cannot be made to consist only of biologically active, specific amino acid sequences that may be needed for specific applications. Prior to this invention, it had been established that fibrillar collagens consist of domains that are responsible for such processes as interaction with cells, binding of growth factors, and interaction with a number of structural proteins present in the extracellular matrix. A normal collagen consists of a sequence of domains that can be represented by a corresponding sequence of labels, e.g., D1D2D3D4. A collagenlike protein of the present invention contains regions of collagen II that contain multiples of a single domain (e.g., D1D1D1D1 or D4D4D4D4) chosen for its specific biological activity. By virtue of the multiplicity of the chosen domain, the density of sites having that specific biological activity is greater than it is in a normal collagen. A collagenlike protein according to this invention can thus be made to have properties that are necessary for tissue engineering.

  20. Primordial magnetogenesis before recombination

    Fabre, Ophélia

    2015-01-01

    The origin of large magnetic fields in the Universe remains currently unknown. We investigate here a mechanism before recombination based on known physics. The source of the vorticity is due to the changes in the photon distribution function caused by the fluctuations in the background photons. We show that the magnetic field generated in the MHD limit, due to the Coulomb scattering, is of the order $10^{-49}$ G. We explicitly show that the magnetic fields generated from this process are sustainable and are not erased by resistive diffusion. We compare the results with current observations and discuss the implications.

  1. Integrating Document Clustering and Topic Modeling

    Xie, Pengtao; Xing, Eric P

    2013-01-01

    Document clustering and topic modeling are two closely related tasks which can mutually benefit each other. Topic modeling can project documents into a topic space which facilitates effective document clustering. Cluster labels discovered by document clustering can be incorporated into topic models to extract local topics specific to each cluster and global topics shared by all clusters. In this paper, we propose a multi-grain clustering topic model (MGCTM) which integrates document clusterin...

  2. Thrombin-dependent modulation of β1-integrin-mediated signaling up-regulates prolidase and HIF-1α through p-FAK in colorectal cancer cells.

    Karna, Ewa; Szoka, Lukasz; Palka, Jerzy

    2012-02-01

    Products of prolidase [E.C. 3.4.13.9] activity, proline or hydroxyproline, contribute to up-regulation of hypoxia-inducible factor-1α (HIF-1α). Prolidase activity is regulated by β(1)-integrin signaling. We studied the effects of echistatin (a well-known disintegrin) and thrombin (a serine protease capable of activation of integrin α(2)β(1) receptor) on prolidase activity and expressions of prolidase, α(2)β(1)-integrin receptor, focal adhesion kinase (FAK), MAP-kinases (ERK(1) and ERK(2)), and nuclear HIF-1α in human colon adenocarcinoma (DLD-1) cells. It has been found that treatment of the cells with thrombin contributes to decrease in the expression of prolidase and simultaneously increase in its phosphorylation, resulting in maintenance of the enzyme activity. The phenomenon was accompanied by thrombin-dependent recovery of depressed autophosphorylation of FAK (pY(397)) under the effect of FAK inhibitor (1,2,4,5-benzenetetramine tetrahydrochloride). Although integrin α(2)β(1) receptor expression was not affected by thrombin, the signaling induced by thrombin up-regulated nuclear HIF-1α expression. It was accompanied by increase in the expression of MAP kinases, ERK1 and ERK2. It suggests that integrin-dependent signaling through p-FAK is up-regulated in DLD-1 cells and it may represent potential target for anti-cancer therapy. PMID:21993963

  3. Effects of normoxic and hypoxic exercise regimens on monocyte-mediated thrombin generation in sedentary men.

    Wang, Jong-Shyan; Chang, Ya-Lun; Chen, Yi-Ching; Tsai, Hsing-Hua; Fu, Tieh-Cheng

    2015-08-01

    Exercise and hypoxia paradoxically modulate vascular thrombotic risks. The shedding of procoagulant-rich microparticles from monocytes may accelerate the pathogenesis of atherothrombosis. The present study explores the manner in which normoxic and hypoxic exercise regimens affect procoagulant monocyte-derived microparticle (MDMP) formation and monocyte-promoted thrombin generation (TG). Forty sedentary healthy males were randomized to perform either normoxic (NET; 21% O2, n=20) or hypoxic (HET; 15% O2, n=20) exercise training (60% VO(2max)) for 30 min/day, 5 days/week for 5 weeks. At rest and immediately after HET (100 W under 12% O2 for 30 min), the MDMP characteristics and dynamic TG were measured by flow cytometry and thrombinography respectively. The results demonstrated that acute 12% O2 exercise (i) increased the release of coagulant factor V (FV)/FVIII-rich, phosphatidylserine (PS)-exposed and tissue factor (TF)-expressed microparticles from monocytes, (ii) enhanced the peak height and rate of TG in monocyte-rich plasma (MRP) and (iii) elevated concentrations of norepinephrine/epinephrine, myeloperoxidase (MPO) and interleukin-6 (IL-6) in plasma. Following the 5-week intervention, HET exhibited higher enhancements of peak work-rate and cardiopulmonary fitness than NET did. Moreover, both NET and HET decreased the FV/FVIII-rich, PS-exposed and TF-expressed MDMP counts and the peak height and rate of TG in MRP following the HET. However, HET elicited more suppression for the HE (hypoxic exercise)-enhanced procoagulant MDMP formation and dynamic TG in MPR and catecholamine/peroxide/pro-inflammatory cytokine levels in plasma than NET. Hence, we conclude that HET is superior to NET for enhancing aerobic capacity. Furthermore, HET effectively suppresses procoagulant MDMP formation and monocyte-mediated TG under severe hypoxic stress, compared with NET. PMID:25826125

  4. Dabigatran etexilate: an oral direct thrombin inhibitor for prophylaxis and treatment of thromboembolic diseases.

    Baetz, Brooke E; Spinler, Sarah A

    2008-11-01

    As the only oral anticoagulation option available in the United States, warfarin use remains widespread. However, concerns of safety remain a substantial issue. Additional anticoagulation options include unfractionated heparin, low-molecular-weight heparins (e.g., enoxaparin, dalteparin, and tinzaparin), and the indirect-acting factor Xa inhibitor, fondaparinux. Direct thrombin inhibitors represent a newer class of anticoagulants used primarily in the treatment of heparin-induced thrombocytopenia and percutaneous coronary interventions. Three intravenous agents are currently available-lepirudin, bivalirudin, and argatroban-with an oral agent, dabigatran etexilate, undergoing clinical investigation. Dabigatran etexilate offers a rapid onset of action after oral administration, reaching peak plasma concentrations and onset of anticoagulant effect within 0.5-2 hours after administration. Studies have demonstrated linear pharmacokinetics, a linear relationship between ecarin clotting time and international normalized ratio, and no known clinically significant drug or food interactions. Dabigatran etexilate has been studied in clinical trials as prophylaxis for venous thromboembolism in patients undergoing total knee replacement or total hip replacement surgeries, as well as for stroke prevention in patients with atrial fibrillation. Dabigatran etexilate has demonstrated superiority and noninferiority to enoxaparin as prophylaxis for venous thromboembolism in patients undergoing orthopedic surgery, with the most frequent adverse effects being gastrointestinal complaints. Elevations in alanine aminotransferase concentrations were noted in small percentages of patients in both the dabigatran etexilate and enoxaparin groups, with no observed dose association. The overall rates of major bleeding were low, with minor bleeding commonly noted, often at surgical sites. Clinical trials of dabigatran etexilate in patients with atrial fibrillation are ongoing. Results of short-term efficacy and safety appear promising. Further research is needed regarding long-term safety and efficacy for other anticoagulation indications. PMID:18956996

  5. Topics

    Mathematics Teaching, 1971

    1971-01-01

    Notes on divisibility using manipulative materials, cyclic groups of functions, Horner's method of synthetic division, arc lengths of cycloids and cardioids, number squares, and students' concepts of mathematics. (MM)

  6. A fully recombinant partial prothrombin complex effectively bypasses fVIII in vitro and in vivo.

    Himmelspach, Michle; Richter, Gnter; Muhr, Evelyn; Varadi, Katalin; Turecek, Peter L; Dorner, Friedrich; Schwarz, Hans Peter; Schlokat, Uwe

    2002-12-01

    The development of inhibitory antibodies is a serious complication in hemophilic patients, severely compromising therapeutic success. Bleeding episodes in affected patients are controlled by treatment with a plasma-derived prothrombin complex concentrate (PCC), activated PCC (APCC) or recombinant activated factor VII. We hypothesized that a recombinant two-component agent consisting of recombinant prothrombin (rfII) and activated factor X (rfXa) would have substantial fVIII bypassing activity and could be a safe alternative therapeutic option. To test this hypothesis we assembled an agent in vitro solely consisting of rfII and rfXa at a molar ratio of 37,500:1. These factors are believed to be responsible for the activity of APCC preparations. Recombinant fX, used as the source for fXa generation, and rfII were purified from serum-free and protein-free conditioned media of stably transfected CHO and BHK tissue culture cells, respectively. Activation of rfX to rfXa was accomplished by the plant protease ficin, obviating the need for a protease derived from a human or animal source. We found that in vitro the complex reduced the abnormally prolonged activated partial thromboplastin time (APTT) of a high-titer fVIII inhibitor plasma similar to an APCC preparation. Furthermore, addition of increasing amounts of rfII/rfXa to inhibitor plasma resulted in a linear dose-dependent increase in the rate of thrombin generation. In a rabbit fVIII inhibitor model, treatment with rfII/rfXa statistically significantly reduced the intensity of the abnormal cuticle bleeding. In the Wessler test, rfII/rfXa showed no thrombogenicity. These data show that a well-defined, particularly safe and efficacious agent with fVIII bypassing activity can be generated from recombinant fII and fXa. PMID:12529752

  7. Selected topics in radiation dosimetry

    This report describes four topics, three of which ultimately have found much interest among dosimetrists. The first topic is dedicated to lyoluminescence, a dosimetric method developed on the fact, that dissolving of irradiated inorganic or organic solids in a suitable solvent is accompanied by the emission of light, the amount of which is proportional to the radiation energy absorbed within the solids. The method finds so much attention in particular, because it allows to obtain mixtures of organics with solvents, that exhibit very close tissue equivalence over a wide range of photon energies and also is very suited for neutron dosimetry. The second topic is on passive solid state radiation dosimetry or radiation induced thermally activated current effects, which turned out to be a very sensitive dosimetric method and has led to the development of ultra high purity sapphire dosimeters of high reliability. The third topic concerns the calibration of ionization chambers in units of absorbed dose, avoiding the transformation of the results of exposure measurements into absorbed dose data by utilizing conversion factors. Ionization chambers properly calibrated in units of absorbed dose serve much to simplify dose assessment in tissue equivalent material or in living tissue. The forth topic finally deals with the application of miniature TL-dosimeters in the determination of phosphate diffusion in sediments, work, which has been performed at the European Joint Research Center Ispra recently. (orig.)

  8. Topical agents in burn care

    Momčilović Dragan

    2002-01-01

    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.

  9. The hemostatic profile of recombinant activated factor VII. Can low concentrations stop bleeding in off-label indications?

    de Lourdes Herrera Maria

    2010-05-01

    Full Text Available Abstract Background High concentrations of recombinant activated factor VII (rFVIIa can stop bleeding in hemophilic patients. However the rFVIIa dose needed for stopping haemhorrage in off-label indications is unknown. Since thrombin is the main hemostatic agent, this study investigated the effect of rFVIIa and tissue factor (TF on thrombin generation (TG in vitro. Methods Lag time (LT, time to peak (TTP, peak TG (PTG, and area under the curve after 35 min (AUCo-35 min with the calibrated automated thrombography was used to evaluate TG. TG was assayed in platelet-rich plasma (PRP samples from 29 healthy volunteers under basal conditions and after platelet stimulation with 5.0 ?g/ml, 2.6 ?g/ml, 0.5 ?g/ml, 0.25 ?g/ml, and 0.125 ?g/ml rFVIIa alone and in normal platelet-poor plasma (PPP samples from 22 healthy volunteers, rFVIIa in combination with various concentrations of TF (5.0, 2.5, 1.25 and 0.5 pM. Results In PRP activated by rFVIIa, there was a statistically significant increase in TG compared to basal values. A significant TF dose-dependent shortening of LT and increased PTG and AUCo?35 min were obtained in PPP. The addition of rFVIIa increased the effect of TF in shorting the LT and increasing the AUCo?35 min with no effect on PTG but were independent of rFVIIa concentration. Conclusion Low concentrations of rFVIIa were sufficient to form enough thrombin in normal PRP or in PPP when combined with TF, and suggest low concentrations for normalizing hemostasis in off-label indications.

  10. Phospholipid-esterified eicosanoids are generated in agonist-activated human platelets and enhance tissue factor-dependent thrombin generation.

    Thomas, Christopher P; Morgan, Lloyd T; Maskrey, Benjamin H; Murphy, Robert C; Kühn, Hartmut; Hazen, Stanley L; Goodall, Alison H; Hamali, Hassan A; Collins, Peter W; O'Donnell, Valerie B

    2010-03-01

    Here, a group of specific lipids, comprising phosphatidylethanolamine (PE)- or phosphatidylcholine (PC)-esterified 12S-hydroxyeicosatetraenoic acid (12S-HETE), generated by 12-lipoxygenase was identified and characterized. 12S-HETE-PE/PCs were formed within 5 min of activation by thrombin, ionophore, or collagen. Esterified HETE levels generated in response to thrombin were 5.85 +/- 1.42 (PE) or 18.35 +/- 4.61 (PC), whereas free was 65.5 +/- 17.6 ng/4 x 10(7) cells (n = 5 separate donors, mean +/- S.E.). Their generation was stimulated by triggering protease-activated receptors-1 and -4 and signaling via Ca(2+) mobilization secretory phospholipase A2, platelet-activating factor-acetylhydrolase, src tyrosine kinases, and protein kinase C. Stable isotope labeling showed that they form predominantly by esterification that occurs on the same time scale as free acid generation. Unlike free 12S-HETE that is secreted, esterified HETEs remain cell-associated, with HETE-PEs migrating to the outside of the plasma membrane. 12-Lipoxygenase inhibition attenuated externalization of native PE and phosphatidylserine and HETE-PEs. Platelets from a patient with the bleeding disorder, Scott syndrome, did not externalize HETE-PEs, and liposomes supplemented with HETE-PC dose-dependently enhanced tissue factor-dependent thrombin generation in vitro. This suggests a role for these novel lipids in promoting coagulation. Thus, oxidized phospholipids form by receptor/agonist mechanisms, not merely as an undesirable consequence of vascular and inflammatory disease. PMID:20061396

  11. Novel magnetic fibrin hydrogel scaffolds containing thrombin and growth factors conjugated iron oxide nanoparticles for tissue engineering

    Ziv-Polat O

    2012-03-01

    Full Text Available Ofra Ziv-Polat1, Hadas Skaat1, Abraham Shahar2, Shlomo Margel11Department of Chemistry, Bar-Ilan Institute of Nanotechnology and Advanced Materials, Ramat-Gan 52900, Israel; 2NVR Research Ltd, Nes-Ziona 74031, IsraelAbstract: Novel tissue-engineered magnetic fibrin hydrogel scaffolds were prepared by the interaction of thrombin-conjugated iron oxide magnetic nanoparticles with fibrinogen. In addition, stabilization of basal fibroblast growth factor (bFGF was achieved by the covalent and physical conjugation of the growth factor to the magnetic nanoparticles. Adult nasal olfactory mucosa (NOM cells were seeded in the transparent fibrin scaffolds in the absence or presence of the free or conjugated bFGF-iron oxide nanoparticles. The conjugated bFGF enhanced significantly the growth and differentiation of the NOM cells in the fibrin scaffolds, compared to the same or even five times higher concentration of the free bFGF. In the presence of the bFGF-conjugated magnetic nanoparticles, the cultured NOM cells proliferated and formed a three-dimensional interconnected network composed mainly of tapered bipolar cells. The magnetic properties of these matrices are due to the integration of the thrombin- and bFGF-conjugated magnetic nanoparticles within the scaffolds. The magnetic properties of these scaffolds may be used in future work for various applications, such as magnetic resonance visualization of the scaffolds after implantation and reloading the scaffolds via magnetic forces with bioactive agents, eg, growth factors bound to the iron oxide magnetic nanoparticles.Keywords: thrombin, fibroblast growth factor, fibrin scaffold, iron oxide nanoparticles, tissue engineering, magnetism, bioactive nanoparticle

  12. Anticoagulant profile of iopamidol and meglumine amidotrizoate and their lack of thrombin generation: an in vitro study

    The aim of this in vitro study was to sketch the subtle anticoagulant profile of iopamidol 300 mg l/ml (low osmolality non ionic contrast medium) and meglumine amidotrizoate 370 mg l/ml (high osmolality ionic contrast medium) in situations where variable amounts of clotting factors are observed and to check whether thrombin-generation significantly occurred in non anti-coagulated blood-contrast materials mixtures. In the first experiment, mixtures of deficient plasmas with a routine plasma pool provided different ranges with a variable amounts of clotting factor II, V, VIII, X, XI and XII. For each clotting factor level studied within these ranges, an activated partial thromboplastin time was determined with either contrast material loaded thromboplastin (5% v/v) used as a control. In the second experiment fibrino-peptide A (FpA) or modified anti-thrombin III (ATM) assays were performed in either (9:1) non anti-coagulated blood contrast materials mixtures or blood-glucose mixtures (control). Differing aPTT prolongation profiles were observed when clotting factors V, VIII, XI and XII were lowered in the plasma. However, neither iopamidol not amidotrizoate induced an aPTT prolongation with decreasing clotting factor II. In the second experiment no significant thrombin generation was observed as both blood - contrast materials mixtures showed significantly lower FpA and ATM levels (p < 0.001) than glucose control after 5 minutes and 10 minutes incubation at room temperature. These findings provide evidence that the use of iopamidol in angiographic procedures does not increase risk of clotting or hemorrhage. (author)

  13. Anticoagulant profile of iopamidol and meglumine amidotrizoate and their lack of thrombin generation: an in vitro study

    Gritli, N.; Nsiri, B.; Mazigh, C.; Ghazouani, E.; M`henni, H.; Machghoul, S.; Gueddiche, M. [Hopital Militaire Principal d`Instruction de Tunis (Tunisia)

    1998-01-01

    The aim of this in vitro study was to sketch the subtle anticoagulant profile of iopamidol 300 mg l/ml (low osmolality non ionic contrast medium) and meglumine amidotrizoate 370 mg l/ml (high osmolality ionic contrast medium) in situations where variable amounts of clotting factors are observed and to check whether thrombin-generation significantly occurred in non anti-coagulated blood-contrast materials mixtures. In the first experiment, mixtures of deficient plasmas with a routine plasma pool provided different ranges with a variable amounts of clotting factor II, V, VIII, X, XI and XII. For each clotting factor level studied within these ranges, an activated partial thromboplastin time was determined with either contrast material loaded thromboplastin (5% v/v) used as a control. In the second experiment fibrino-peptide A (FpA) or modified anti-thrombin III (ATM) assays were performed in either (9:1) non anti-coagulated blood contrast materials mixtures or blood-glucose mixtures (control). Differing aPTT prolongation profiles were observed when clotting factors V, VIII, XI and XII were lowered in the plasma. However, neither iopamidol not amidotrizoate induced an aPTT prolongation with decreasing clotting factor II. In the second experiment no significant thrombin generation was observed as both blood - contrast materials mixtures showed significantly lower FpA and ATM levels (p < 0.001) than glucose control after 5 minutes and 10 minutes incubation at room temperature. These findings provide evidence that the use of iopamidol in angiographic procedures does not increase risk of clotting or hemorrhage. (author)

  14. Effect of the oral thrombin inhibitor dabigatran on allergic lung inflammation induced by repeated house dust mite administration in mice.

    de Boer, Johannes D; Berkhout, Lea C; de Stoppelaar, Sacha F; Yang, Jack; Ottenhoff, Roelof; Meijers, Joost C M; Roelofs, Joris J T H; van't Veer, Cornelis; van der Poll, Tom

    2015-10-15

    Asthma is a chronic disease of the airways; asthma patients are hampered by recurrent symptoms of dyspnoea and wheezing caused by bronchial obstruction. Most asthma patients suffer from chronic allergic lung inflammation triggered by allergens such as house dust mite (HDM). Coagulation activation in the pulmonary compartment is currently recognized as a feature of allergic lung inflammation, and data suggest that coagulation proteases further drive inflammatory mechanisms. Here, we tested whether treatment with the oral thrombin inhibitor dabigatran attenuates allergic lung inflammation in a recently developed HDM-based murine asthma model. Mice were fed dabigatran (10 mg/g) or placebo chow during a 3-wk HDM airway exposure model. Dabigatran treatment caused systemic thrombin inhibitory activity corresponding with dabigatran levels reported in human trials. Surprisingly, dabigatran did not lead to inhibition of HDM-evoked coagulation activation in the lung as measured by levels of thrombin-antithrombin complexes and D-dimer. Repeated HDM administration caused an influx of eosinophils and neutrophils into the lungs, mucus production in the airways, and a T helper 2 response, as reflected by a rise in bronchoalveolar IL-4 and IL-5 levels and a systemic rise in IgE and HDM-IgG1. Dabigatran modestly improved HDM-induced lung pathology (P < 0.05) and decreased IL-4 levels (P < 0.01), without influencing other HDM-induced responses. Considering the limited effects of dabigatran in spite of adequate plasma levels, these results argue against clinical evaluation of dabigatran in patients with asthma. PMID:26320153

  15. Topical corticosteroid addiction and phobia

    Aparajita Ghosh

    2014-01-01

    Full Text Available Corticosteroids, one of the most widely prescribed topical drugs, have been used for about six decades till date. However, rampant misuse and abuse down the years has given the drug a bad name. Topical steroid abuse may lead to two major problems which lie at the opposing ends of the psychosomatic spectrum. Topical steroid addiction, a phenomenon that came to be recognized about a decade after the introduction of the molecule is manifested as psychological distress and rebound phenomenon on stoppage of the drug. The rebound phenomenon, which can affect various parts of the body particularly the face and the genitalia has been reported by various names in the literature. TC phobia which lies at the opposite end of the psychiatric spectrum of steroid abuse has been reported particularly among parents of atopic children. Management of both conditions is difficult and frustrating. Psychological counseling and support can be of immense help in both the conditions.

  16. Topical corticosteroid addiction and phobia.

    Ghosh, Aparajita; Sengupta, Sujata; Coondoo, Arijit; Jana, Amlan Kusum

    2014-09-01

    Corticosteroids, one of the most widely prescribed topical drugs, have been used for about six decades till date. However, rampant misuse and abuse down the years has given the drug a bad name. Topical steroid abuse may lead to two major problems which lie at the opposing ends of the psychosomatic spectrum. Topical steroid addiction, a phenomenon that came to be recognized about a decade after the introduction of the molecule is manifested as psychological distress and rebound phenomenon on stoppage of the drug. The rebound phenomenon, which can affect various parts of the body particularly the face and the genitalia has been reported by various names in the literature. TC phobia which lies at the opposite end of the psychiatric spectrum of steroid abuse has been reported particularly among parents of atopic children. Management of both conditions is difficult and frustrating. Psychological counseling and support can be of immense help in both the conditions. PMID:25284851

  17. Quantum mechanics II advanced topics

    Rajasekar, S

    2015-01-01

    Quantum Mechanics II: Advanced Topics uses more than a decade of research and the authors’ own teaching experience to expound on some of the more advanced topics and current research in quantum mechanics. A follow-up to the authors introductory book Quantum Mechanics I: The Fundamentals, this book begins with a chapter on quantum field theory, and goes on to present basic principles, key features, and applications. It outlines recent quantum technologies and phenomena, and introduces growing topics of interest in quantum mechanics. The authors describe promising applications that include ghost imaging, detection of weak amplitude objects, entangled two-photon microscopy, detection of small displacements, lithography, metrology, and teleportation of optical images. They also present worked-out examples and provide numerous problems at the end of each chapter.

  18. Isolation and characterization of a serine proteinase with thrombin-like activity from the venom of the snake Bothrops asper

    A.V Prez; Rucavado, A; Sanz, L.; Calvete, J. J.; Gutirrez, J.M

    2008-01-01

    A serine proteinase with thrombin-like activity was isolated from the venom of the Central American pit viper Bothrops asper. Isolation was performed by a combination of affinity chromatography on aminobenzamidine-Sepharose and ion-exchange chromatography on DEAE-Sepharose. The enzyme accounts for approximately 0.13% of the venom dry weight and has a molecular mass of 32 kDa as determined by SDS-PAGE, and of 27 kDa as determined by MALDI-TOF mass spectrometry. Its partial amino acid sequence ...

  19. Percutaneous Thrombin Injection of a Femoral Artery Pseudoaneurysm with Simultaneous Venous Balloon Occlusion of a Communicating Arteriovenous Fistula

    An 82-year-old woman developed acute occlusion of her right coronary artery. She underwent percutaneous coronary stent placement and aortic balloon pump installation. In the postprocedural period, she developed a common femoral artery pseudoaneurysm (PSA) that communicated with the common femoral vein via an arteriovenous fistula (AVF). After unsuccessful ultrasound-guided compression, ultrasound-guided thrombin injection of the PSA was performed, with simultaneous balloon occlusion of the common femoral vein at the level of the AVF. There was complete thrombosis of the PSA and AVF.

  20. In vitro assessment of Tc-99m labeled bovine thrombin and streptokinase-activated human plasmin: concise communication. [Iodine 125

    Wong, D.W.; Tanaka, T.; Mishkin, F.; Lee, T.

    1979-09-01

    Bovine thrombin and streptokinase-activated human plasmin have been labeled with Tc-99m using stannous reduction of pertechnetate under physiological conditions (pH 7.4). The binding efficiency of radiotechnetium to these enzymes is greater than 94%, with less than 5% of reduced but unbound Tc-99m (Sn) complex as assayed by ascending paper radiochromatography using ITLC silica gel plate. Free or unbound pertechnetate is less than 1%. In vitro enzymatic analyses of the Tc-99m-labeled enzymes demonstrate no evidence of protein denaturation or significant loss of enzymatic activity after labeling. Both labeled enzymes are biochemically active in vitro with their respective substrates.

  1. In vitro assessment of Tc-99m labeled bovine thrombin and streptokinase-activated human plasmin: concise communication

    Bovine thrombin and streptokinase-activated human plasmin have been labeled with Tc-99m using stannous reduction of pertechnetate under physiological conditions (pH 7.4). The binding efficiency of radiotechnetium to these enzymes is greater than 94%, with less than 5% of reduced but unbound Tc-99m (Sn) complex as assayed by ascending paper radiochromatography using ITLC silica gel plate. Free or unbound pertechnetate is less than 1%. In vitro enzymatic analyses of the Tc-99m-labeled enzymes demonstrate no evidence of protein denaturation or significant loss of enzymatic activity after labeling. Both labeled enzymes are biochemically active in vitro with their respective substrates

  2. Topics in millimeter wave technology

    Button, Kenneth

    1988-01-01

    Topics in Millimeter Wave Technology, Volume 1 presents topics related to millimeter wave technology, including fin-lines and passive components realized in fin-lines, suspended striplines, suspended substrate microstrips, and modal power exchange in multimode fibers. A miniaturized monopulse assembly constructed in planar waveguide with multimode scalar horn feeds is also described. This volume is comprised of five chapters; the first of which deals with the analysis and synthesis techniques for fin-lines as well as the various passive components realized in fin-line. Tapers, discontinuities,

  3. Selected topics in nuclear structure

    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 β-decay; semiclassical approach of large amplitude collective motion and structure of hot nuclei

  4. Spin dependent recombination

    The spin dependent recombination (SDR) technique is used to observe the 29Si hyperfine spectra of radiation-induced Pb centers at the Si/SiO2 interface in a MOSFET. The Pb center is a paramagnetic, trivalent silicon defect that is the dominant radiation-induced interface state. The 29Si hyperfine spectra give detailed atomic scale information about the Pb center. The authors' SDR results show that the 29Si hyperfine spectra vary with surface potential. This result indicates that differences in the defect's local geometry lead to substantial differences in the defect's energy level. However, the 29Si hyperfine spectra are found to be relatively independent of the ionizing radiation dosage

  5. High-resolution NMR studies of fibrinogen-like peptides in solution: Interaction of thrombin with residues 1-23 of the Aα chain of human fibrinogen

    The interaction of the following human fibrinogen-like peptides with bovine thrombin was studied by use of one- and two-dimensional NMR techniques in aqueous solution: Ala(1)-Asp-Ser-Gly-Glu-Gly-Asp-Phe(8)-Leu-Ala-Glu-Gly-Gly-Gly-Val-Arg(16)-Gly(17)-Pro-Arg(19)-Val(20)-Val-Glu-Arg (F10), residues 1-16 of F10 (fibrinopeptide A), residues 17-23 of F10 (F12), residues 1-20 of F10 (F13), residues 6-20 of F10 with Arg(16) replaces by a Gly residue (F14), and residues 6-19 of F10 with Arg(16) replaced by a Leu residue (F15). At pH 5.3 and 25 degree C, the Arg(16)-Gly(17) peptide bonds of both peptides F10 and F13 were cleaved instantaneously in the presence of 0.6 mM thrombin, whereas the cleavage of the Arg(19)-Val(20) peptide bonds in peptides F12, F13, and F14 took over 1 h for completion. On the basis of observations of line broadening, fibrinopeptide A was found to bind to thrombin. While resonances from residues Ala(1)-Glu(5) were little affected, binding of fibrinopeptide A to thrombin caused significant line broadening of NH and side-chain proton resonances within residues Asp(7)-Arg(16). Peptides with Arg(16) replaced by Gly and Leu, respectively, i.e.; F14 and F15, were also found to bind to thrombin but with a different conformation, as indicated by the absence of the long-range NOEs observed with fibrinopeptide A. Residues Asp(7)-Arg(16) constitute an essential structural element in the interaction of thrombin with fibrinogen

  6. Topics in Mitigating Radar Bias

    Serakos, Demetrios; Youssef, Hazim

    2008-01-01

    In this paper, we investigate two topics related to mitigating the effect of radar bias in ballistic missile tracking applications. We determine the absolute bias between two radars in polar coordinates when their relative bias is given in rectangular coordinates. Using this result, we then obtain the optimized steady-state filter to handle the random bias.

  7. Selected topics in nuclear structure

    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.)

  8. Psoriasis: consensus on topical therapies

    van de Kerkhof, P C M; Barker, J; Griffiths, C E M; Kragballe, K; Mason, J; Menter, A; Papp, K

    2008-01-01

    Objective A consensus conference was convened to evaluate the topical treatment of psoriasis. Participants Members of the International Psoriasis Council (IPC) with broad clinical experience in the treatment of psoriasis and a specialist in meta- and pharmacoeconomic analyses were invited to...

  9. Two topics in quantum chromodynamics

    Bjorken, J.D.

    1989-12-01

    The two topics are (1) estimates of perturbation theory coefficients for R(e{sup +}e{sup -} {yields} hadrons), and (2) the virtual-photon structure function, with emphasis on the analytic behavior in its squared mass. 20 refs., 4 figs., 2 tabs.

  10. Topics in optics and music

    Sparks, Andrew W.

    2012-10-01

    While the use of optics in the playback of music has been a tremendously successful technology and laser light shows are a common occurrence, other intersections of optics and music tend to be less well known. Topics such as optics-based instruments, performance tools and effects, instrument characterization and manufacturing, recording, playback, and signal processing are explored.

  11. Two topics in quantum chromodynamics

    The two topics are (1) estimates of perturbation theory coefficients for R(e+e- → hadrons), and (2) the virtual-photon structure function, with emphasis on the analytic behavior in its squared mass. 20 refs., 4 figs., 2 tabs

  12. Seven topics in perturbative QCD

    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

  13. Topics on Galactic Chemical Evolution

    Prantzos, Nikos

    2011-01-01

    I discuss three different topics in Galactic chemical evolution:the "puzzling" absence of any observational signature of secondary elements ; the building of the Galactic halo in the framework of hierarchical galaxy formation, as evidenced from its metallicity distribution ; and the potentially important role that radial migration may play in the evolution of galactic disks, according to recent studies.

  14. CT-Guided Thrombin Injection to Control Rapid Expansion of Ascending Aortic False Aneurysm 15 Months After Bentall–Bono Operation

    We report a case of 57-year-old man treated emergently with CT-guided local thrombin injection as the first, life-saving step for control rapid expansion of the aortic pseudoaneurysm. Fifteen months earlier, he was operated on for ascending aortic true aneurysm and coronary artery disease. Upon admission, he had an anterior thoracic wall pulsatile tumor. Due to critical status, definite surgery was postponed and thrombin was injected close to the origin of pseudoaneurysm. It controlled successfully, bleeding from the ascending aorta and enabled the patient to survive the acute phase.

  15. Recombinant protein scaffolds for tissue engineering

    New biological materials for tissue engineering are now being developed using common genetic engineering capabilities to clone and express a variety of genetic elements that allow cost-effective purification and scaffold fabrication from these recombinant proteins, peptides or from chimeric combinations of these. The field is limitless as long as the gene sequences are known. The utility is dependent on the ease, product yield and adaptability of these protein products to the biomedical field. The development of recombinant proteins as scaffolds, while still an emerging technology with respect to commercial products, is scientifically superior to current use of natural materials or synthetic polymer scaffolds, in terms of designing specific structures with desired degrees of biological complexities and motifs. In the field of tissue engineering, next generation scaffolds will be the key to directing appropriate tissue regeneration. The initial period of biodegradable synthetic scaffolds that provided shape and mechanical integrity, but no biological information, is phasing out. The era of protein scaffolds offers distinct advantages, particularly with the combination of powerful tools of molecular biology. These include, for example, the production of human proteins of uniform quality that are free of infectious agents and the ability to make suitable quantities of proteins that are found in low quantity or are hard to isolate from tissue. For the particular needs of tissue engineering scaffolds, fibrous proteins like collagens, elastin, silks and combinations of these offer further advantages of natural well-defined structural scaffolds as well as endless possibilities of controlling functionality by genetic manipulation. (topical review)

  16. Quantification of thymidine kinase (TK1) mRNA in normal and leukemic cells and investigation of structure-function relatiosnhip of recombinant TK1enzyme

    Kristensen, Tina

    lymphocytes. As the high TKI mRNA level is not translated into an active enzyme, these results indicate a defect in the regulation of TKI in CLL cells. For the studies of the structure-function relationship of TKI a recombinant TKI protein, which is expressed as a glutathione-S-transferase (GST) fusion...... protein was used. TKI protein is cleaved from the GST-part with thrombin. Two TKI mutants, TKI-l 93 and TKI-l 76, with deletions from the C-terminal were constructed by the recombinant PCR method. Deletion of 57 amino acids from the C-terminal (TKI- 176) results in an inactive enzyme. Deletion of 40 amino...

  17. Purification, crystallization and preliminary X-ray diffraction analysis of saxthrombin, a thrombin-like enzyme from Gloydius saxatilis venom

    The thrombin-like enzyme saxthrombin has been purified from G. saxatilis snake venom. Crystallization conditions were found and a data set was obtained to 1.43 Å. The snake-venom thrombin-like enzymes (SVTLEs) are a class of serine proteinases that show fibrinogen-clotting and esterolytic activities. Most TLEs convert fibrinogen to fibrin by releasing either fibrinopeptide A or fibrinopeptide B and cannot activate factor XIII. The enzymes hydrolyze fibrinogen to produce non-cross-linked fibrins, which are susceptible to the lytic action of plasmin. Because of these physiological properties, TLEs have important medical applications in myocardial infarction, ischaemic stroke and thrombotic diseases. Here, a three-step chromatography procedure was used to purify saxthrombin (AAP20638) from Gloydius saxatilis venom to homogeneity. Its molecular weight is about 30 kDa as estimated by SDS–PAGE. A saxthrombin crystal was obtained using the hanging-drop vapour-diffusion method and diffracted to a resolution limit of 1.43 Å. The crystal belongs to space group C2, with unit-cell parameters a = 97.23, b = 52.21, c = 50.10 Å, β = 96.72°, and the Matthews coefficient (VM) was calculated to be 2.13 Å3 Da−1 with one molecule in the asymmetric unit

  18. Isolation and characterization of a serine proteinase with thrombin-like activity from the venom of the snake Bothrops asper

    A.V Prez

    2008-01-01

    Full Text Available A serine proteinase with thrombin-like activity was isolated from the venom of the Central American pit viper Bothrops asper. Isolation was performed by a combination of affinity chromatography on aminobenzamidine-Sepharose and ion-exchange chromatography on DEAE-Sepharose. The enzyme accounts for approximately 0.13% of the venom dry weight and has a molecular mass of 32 kDa as determined by SDS-PAGE, and of 27 kDa as determined by MALDI-TOF mass spectrometry. Its partial amino acid sequence shows high identity with snake venom serine proteinases and a complete identity with a cDNA clone previously sequenced from this species. The N-terminal sequence of the enzyme is VIGGDECNINEHRSLVVLFXSSGFL CAGTLVQDEWVLTAANCDSKNFQ. The enzyme induces clotting of plasma (minimum coagulant dose = 4.1 g and fibrinogen (minimum coagulant dose = 4.2 g in vitro, and promotes defibrin(ogenation in vivo (minimum defibrin(ogenating dose = 1.0 g. In addition, when injected intravenously in mice at doses of 5 and 10 g, it induces a series of behavioral changes, i.e., loss of the righting reflex, opisthotonus, and intermittent rotations over the long axis of the body, which closely resemble the `gyroxin-like' effect induced by other thrombin-like enzymes from snake venoms.

  19. Isolation and characterization of a serine proteinase with thrombin-like activity from the venom of the snake Bothrops asper.

    Prez, A V; Rucavado, A; Sanz, L; Calvete, J J; Gutirrez, J M

    2008-01-01

    A serine proteinase with thrombin-like activity was isolated from the venom of the Central American pit viper Bothrops asper. Isolation was performed by a combination of affinity chromatography on aminobenzamidine-Sepharose and ion-exchange chromatography on DEAE-Sepharose. The enzyme accounts for approximately 0.13% of the venom dry weight and has a molecular mass of 32 kDa as determined by SDS-PAGE, and of 27 kDa as determined by MALDI-TOF mass spectrometry. Its partial amino acid sequence shows high identity with snake venom serine proteinases and a complete identity with a cDNA clone previously sequenced from this species. The N-terminal sequence of the enzyme is VIGGDECNINEHRSLVVLFXSSGFL CAGTLVQDEWVLTAANCDSKNFQ. The enzyme induces clotting of plasma (minimum coagulant dose = 4.1 microg) and fibrinogen (minimum coagulant dose = 4.2 microg) in vitro, and promotes defibrin(ogen)ation in vivo (minimum defibrin(ogen)ating dose = 1.0 microg). In addition, when injected intravenously in mice at doses of 5 and 10 microg, it induces a series of behavioral changes, i.e., loss of the righting reflex, opisthotonus, and intermittent rotations over the long axis of the body, which closely resemble the ;gyroxin-like' effect induced by other thrombin-like enzymes from snake venoms. PMID:17994164

  20. A label-free electrochemical aptasensor based on the catalysis of manganese porphyrins for detection of thrombin.

    Zheng, Yingning; Yuan, Yali; Chai, Yaqin; Yuan, Ruo

    2015-04-15

    A novel manganese porphyrin (MnPP)-catalyzed aerobic oxidation of l-cysteine to disulfides (RSSR) was firstly found and applied into electrochemical aptasensor with a label-free technique for signal amplification. The possible catalytic mechanism of the catalytic reaction where MnPP catalyzed l-cysteine with thiol (RSH) structure to RSSR was discussed in detail. For fabrication of the aptasensor, thionine (Thi), which served as an electron mediator, was mixed with MnPP and immobilized on the nafion coated carbon electrode through ion exchange adsorption. Gold nanoparticle (nano-Au) was assembled on the Thi for immobilizing thrombin binding aptamer (TBA). In the presence of thrombin (TB), TBA will capture TB and form TBA-TB composite thus perturbed electron transfer, leading to decrease of the current for quantitatively detecting TB. Under optimal condition, the electrochemical aptasensor exhibited a linear range of 0.1-25nM with a detection limit of 0.02nM. This work opens a novel way for signal amplification study about porphyrins that served as mimetic enzyme to thiol in electrochemical aptasensor. PMID:25530538

  1. Metabolism of 1-alkyl-2-acyl-GPC in human platelets in response to stimulation by thrombin

    Washed human platelets were incubated with radioactive 1-[3H]alkyl-2-hydroxyglycero-3-phosphocholine (lyso-PAF) at 37 degrees C. [3H]lyso-PAF was converted by platelets into [3H]alkylacyl-GPC which was incorporated. Incorporation of radioactivity was time dependent and reached a maximum of 57 percent in one h. This formation and incorporation of [3H]alkylacyl-GPC was inhibited (50%) by extracellular calcium (1.3 mM). Labeled platelets were treated for 5 min with either thrombin (2.5 U/ml) or saline solution. While there was no change in the saline control, thrombin induced a reduction in the content of [3H]alkylacyl-GPC, accompanied by an increase in [3H]lyso-PAF presumably by stimulation of phospholipase A2. There was no apparent increase in radioactivity comigrating with PAF. This was probably due to the overwhelming dilution of the radioactive alkylacyl-GPC by the endogenous nonradioactive compound (ratio-1/3200). These studies suggest that human platelets can take up lyso-PAF and acylate it to alkylacyl-GPC which is susceptible to phospholipase A2 activity

  2. Thrombin-mediated ratiometric two-photon fluorescent probe for selective imaging of endogenous ultratrace glutathione in platelet.

    Zhang, Hua; Wang, Caixia; Wang, Ge; Wang, Kui; Jiang, Kai

    2016-04-15

    Ultratrace change of reduced glutathione (GSH) can weaken coagulation function of platelet (PLT). Thus, rapid and sensitive imaging of GSH specific in PLT is beneficial for monitoring coagulation function of PLT. Many fluorescent probes for GSH have been reported, but ratio fluorescent probe with excellent two-photon property for screening PLT from peripheral blood and quantitative imaging of GSH are scarce. In this work, a thrombin-mediated two-photon GSH-specific fluorescent probe (IQDC-L) was reported. Sulfuric diamide, a key group as linker, was introduced into IQDC-L, which resulted in not only specific selectivity for GSH, but also FRET occurring in probe. When IQDC-L encountered GSH, "S-N" in sulfonamide group was cut off, and FRET was inhibited. Furthermore, fluorescence intensities at 520 and 595nm presented linear change on ratio mode in the range of GSH (2.0-65nM). The lowest detection for GSH was as low as 0.083nM. Intriguingly, IQDC-L under thrombin-mediated was able to screen PLT from peripheral blood without any interference. Thus, IQDC-L could be used to screen PLT from peripheral blood, and simultaneously, to in situ image ultratrace GSH. PMID:26649492

  3. Purification, crystallization and preliminary X-ray diffraction analysis of saxthrombin, a thrombin-like enzyme from Gloydius saxatilis venom

    Wei, Wenqing; Zhao, Wei [Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027 (China); Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027 (China); Wang, Xiaoping [National Conservation of Snake Island and Laotieshan Mountain, Dalian, Liaoning, 116041 (China); Teng, Maikun, E-mail: mkteng@ustc.edu.cn; Niu, Liwen, E-mail: mkteng@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230027 (China); Key Laboratory of Structural Biology, Chinese Academy of Sciences, 96 Jinzhai Road, Hefei, Anhui 230027 (China)

    2007-08-01

    The thrombin-like enzyme saxthrombin has been purified from G. saxatilis snake venom. Crystallization conditions were found and a data set was obtained to 1.43 Å. The snake-venom thrombin-like enzymes (SVTLEs) are a class of serine proteinases that show fibrinogen-clotting and esterolytic activities. Most TLEs convert fibrinogen to fibrin by releasing either fibrinopeptide A or fibrinopeptide B and cannot activate factor XIII. The enzymes hydrolyze fibrinogen to produce non-cross-linked fibrins, which are susceptible to the lytic action of plasmin. Because of these physiological properties, TLEs have important medical applications in myocardial infarction, ischaemic stroke and thrombotic diseases. Here, a three-step chromatography procedure was used to purify saxthrombin (AAP20638) from Gloydius saxatilis venom to homogeneity. Its molecular weight is about 30 kDa as estimated by SDS–PAGE. A saxthrombin crystal was obtained using the hanging-drop vapour-diffusion method and diffracted to a resolution limit of 1.43 Å. The crystal belongs to space group C2, with unit-cell parameters a = 97.23, b = 52.21, c = 50.10 Å, β = 96.72°, and the Matthews coefficient (V{sub M}) was calculated to be 2.13 Å{sup 3} Da{sup −1} with one molecule in the asymmetric unit.

  4. Delayed recombination and standard rulers

    Measurements of baryonic acoustic oscillations (BAOs) in galaxy surveys have been recognized as a powerful tool for constraining dark energy. However, this method relies on the knowledge of the size of the acoustic horizon at recombination derived from cosmic microwave background (CMB) anisotropy measurements. This estimate is typically derived assuming a standard recombination scheme; additional radiation sources can delay recombination altering the cosmic ionization history and the cosmological inferences drawn from CMB and BAO data. In this paper we quantify the effect of delayed recombination on the determination of dark energy parameters from future BAO surveys such as the Baryon Oscillation Spectroscopic Survey and the Wide-Field Multi-Object Spectrograph. We find the impact to be small but still not negligible. In particular, if recombination is nonstandard (to a level still allowed by CMB data), but this is ignored, future surveys may incorrectly suggest the presence of a redshift-dependent dark energy component. On the other hand, in the case of delayed recombination, adding to the analysis one extra parameter describing deviations from standard recombination does not significantly degrade the error bars on dark energy parameters and yields unbiased estimates. This is due to the CMB-BAO complementarity.

  5. Ethical use of topical corticosteroids

    Abir Saraswat

    2014-01-01

    Full Text Available Dermatologists rely very heavily on corticosteroids for treating many common dermatoses. Concerns about their incorrect use are widely expressed both in lay public and specialist discourse. From the point of view of medical ethics, issues of autonomy, beneficence and non-maleficence are all raised frequently when we prescribe topical corticosteroids to our patients. We need to be aware of situations when conflicts between these issues arise and have a clear thought process about resolving them. This can only be achieved if we have a thorough understanding of the skin disease being treated coupled with expertise in the use of the varied potencies and available dosage forms of topical corticosteroids. A good understanding of human psychology and effective communication is also needed to use these agents optimally.

  6. Retapamulin: A newer topical antibiotic

    D Dhingra

    2013-01-01

    Full Text Available Impetigo is a common childhood skin infection. There are reports of increasing drug resistance to the currently used topical antibiotics including fusidic acid and mupirocin. Retapamulin is a newer topical agent of pleuromutilin class approved by the Food and Drug Administration for treatment of impetigo in children and has been recently made available in the Indian market. It has been demonstrated to have low potential for the development of antibacterial resistance and a high degree of potency against poly drug resistant Gram-positive bacteria found in skin infections including Staphylococcus aureus strains. The drug is safe owing to low systemic absorption and has only minimal side-effect of local irritation at the site of application.

  7. Topics on electricity transmission pricing

    Bjørndal, Mette

    2000-01-01

    The efficiency of the power market is heavily affected by the operation and pricing of the transmission system and the topic of this thesis concerns the interaction of the transmission network and the energy markets. After describing different power flow models, we provide an overview of models developed to efficiently coordinate the allocation of transmission resources. The focus is mainly on short-term efficiency, and the survey is only partial, but provides an integrated overview of some o...

  8. Hot topics from the Tevatron

    Glenzinski, D.; /Fermilab

    2008-01-01

    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.

  9. Topical Immunotherapy in Alopecia Areata

    Singh, Gurcharan; Lavanya, MS

    2010-01-01

    Alopecia Areata (AA) is a common non-scarring alopecia directed against the anagenic hair follicle. Various treatment modalities have been used for the treatment of severe AA. Topical immunotherapy is the best documented treatment so far for severe and refractory AA. Dinitrochlorobenzene (DNCB), squaric acid dibutylester (SADBE), and diphencyprone (DPCP) are the contact allergens used for this purpose. DNCB has been found to be mutagenic by the Ames test and is largely replaced by DPCP and SA...

  10. Probabilistic analysis and related topics

    Bharucha-Reid, A T

    1983-01-01

    Probabilistic Analysis and Related Topics, Volume 3 focuses on the continuity, integrability, and differentiability of random functions, including operator theory, measure theory, and functional and numerical analysis. The selection first offers information on the qualitative theory of stochastic systems and Langevin equations with multiplicative noise. Discussions focus on phase-space evolution via direct integration, phase-space evolution, linear and nonlinear systems, linearization, and generalizations. The text then ponders on the stability theory of stochastic difference systems and Marko

  11. Topics in Local Economic Development

    Bubbico, Antonio

    2014-01-01

    This thesis contributes to the current debate in literature about local economic development by considering two different topics: quality of institutions, and the role of clusters in innovation and productivity growth. The research is built upon three papers. The first paper deals with the analysis of the effect of administrative continuity on administrative efficiency. The analysis underlines the importance of different typologies of social capital. Findings reveal a positive impact on ...

  12. Stochastic Analysis and Related Topics

    Ustunel, Ali

    1988-01-01

    The Silvri Workshop was divided into a short summer school and a working conference, producing lectures and research papers on recent developments in stochastic analysis on Wiener space. The topics treated in the lectures relate to the Malliavin calculus, the Skorohod integral and nonlinear functionals of white noise. Most of the research papers are applications of these subjects. This volume addresses researchers and graduate students in stochastic processes and theoretical physics.

  13. Preface to Special Topic: Optofluidics

    LIU, AI-QUN

    2010-01-01

    This Special Topic section of Biomicrofluidics is on optofluidics or micro-optofluidic systems (MOFS), a burgeoning technology that aims to manipulate light and fluid at microscale and exploits their interaction to create highly versatile devices and integrated systems. This special issue puts together various contributed articles focusing on optofluidics or MOFS, which help inspire new research ideas and innovation in the microfluidics and nanofluidics community.

  14. Topics in clinical oncology. 15

    The monograph comprising primarily papers on topical subjects of oncology and cancer research, contains also a selection of papers presented at the 2. Congress of the Czechoslovak Society of Nuclear Medicine and Radiation Hygiene. Seven papers were selected on behalf of their subject related to clinical oncology. All of them were iputted in INIS; five of them deal with the scintiscanning of the skeleton of cancer patients, one with radioimmunodetection of tumors, and one with radionuclide lymphography. (A.K.)

  15. Iodine chemistry in hydrogen recombiners

    Sabroux, J.C. [IRSN/DSU/SERAC, B.P. No. 68, 91192 Gif-sur-Yvette cedex (France); Deschamps, F. [APTUS, 77 rue des Chantiers, 78000 Versailles (France)

    2005-07-01

    Hydrogen recombiners, recently introduced in the French nuclear reactor buildings, display high temperature (up to about 900 deg. C) and several thousands square meters of a very reactive surface when operating during a severe accident scenario. Small scale analytical experiments show that cesium and cadmium iodides are unstable, and generate volatile iodine, when heated in an oven that reproduces most physico-chemical parameters of recombiner operation. Based on these results, and due to its potential with regard to the environmental source term of a severe accident, iodine chemistry in hydrogen recombiners deserves close and careful scrutiny. (authors)

  16. Iodine chemistry in hydrogen recombiners

    Hydrogen recombiners, recently introduced in the French nuclear reactor buildings, display high temperature (up to about 900 deg. C) and several thousands square meters of a very reactive surface when operating during a severe accident scenario. Small scale analytical experiments show that cesium and cadmium iodides are unstable, and generate volatile iodine, when heated in an oven that reproduces most physico-chemical parameters of recombiner operation. Based on these results, and due to its potential with regard to the environmental source term of a severe accident, iodine chemistry in hydrogen recombiners deserves close and careful scrutiny. (authors)

  17. Dynamic Joint Sentiment-Topic Model

    He Y.; Lin C; Gao W; Wong K.-F.

    2013-01-01

    Social media data are produced continuously by a large and uncontrolled number of users. The dynamic nature of such data requires the sentiment and topic analysis model to be also dynamically updated, capturing the most recent language use of sentiments and topics in text. We propose a dynamic joint sentiment-topic model (dJST) which allows the detection and tracking of views of current and recurrent interests and shifts in topic and sentiment. Both topic and sentiment dynamics are captured b...

  18. Constraining topic maps : a TMCL declarative implementation

    Ramalho, Jos Carlos; Librelotto, Giovani Rubert; Henriques, Pedro Rangel

    2005-01-01

    This paper describes the design of an XML language to formally specify constraints over Topic Maps (XTche). This language allows to express contextual conditions on classes of Topic Maps that are further processed by a XSLT based processor. With XTche, a topic map designer defines a set of restrictions that guarantee that a particular topic map is semantically valid. Topic Maps tend to grow quite fast. Most times the designer has some restrictions in mind like: what kind of ...

  19. The Anopheles gambiae cE5, a tight- and fast-binding thrombin inhibitor with post-transcriptionally regulated salivary-restricted expression

    Ronca, R.; Kotsyfakis, Michalis; Lombardo, F.; Rizzo, C.; Currà, C.; Ponzi, M.; Fiorentino, G.; Ribeiro, J.M.C.; Arcà, B.

    2012-01-01

    Roč. 42, č. 9 (2012), s. 610-620. ISSN 0965-1748 R&D Projects: GA ČR GAP502/12/2409 Institutional research plan: CEZ:AV0Z60220518 Keywords : Anopheles * Saliva ry protein * Anti-thrombin * Anophelin * Hematophagy * Post-transcriptional regulation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.234, year: 2012

  20. Stable recombination hotspots in birds.

    Singhal, Sonal; Leffler, Ellen M; Sannareddy, Keerthi; Turner, Isaac; Venn, Oliver; Hooper, Daniel M; Strand, Alva I; Li, Qiye; Raney, Brian; Balakrishnan, Christopher N; Griffith, Simon C; McVean, Gil; Przeworski, Molly

    2015-11-20

    The DNA-binding protein PRDM9 has a critical role in specifying meiotic recombination hotspots in mice and apes, but it appears to be absent from other vertebrate species, including birds. To study the evolution and determinants of recombination in species lacking the gene that encodes PRDM9, we inferred fine-scale genetic maps from population resequencing data for two bird species: the zebra finch, Taeniopygia guttata, and the long-tailed finch, Poephila acuticauda. We found that both species have recombination hotspots, which are enriched near functional genomic elements. Unlike in mice and apes, most hotspots are shared between the two species, and their conservation seems to extend over tens of millions of years. These observations suggest that in the absence of PRDM9, recombination targets functional features that both enable access to the genome and constrain its evolution. PMID:26586757

  1. Enhanced electrochemiluminescence quenching of CdS:Mn nanocrystals by CdTe QDs-doped silica nanoparticles for ultrasensitive detection of thrombin

    Shan, Yun; Xu, Jing-Juan; Chen, Hong-Yuan

    2011-07-01

    This work reports an aptasensor for ultrasensitive detection of thrombin based on remarkably efficient energy-transfer induced electrochemiluminescence (ECL) quenching from CdS:Mn nanocrystals (NCs) film to CdTe QDs-doped silica nanoparticles (CdTe/SiO2 NPs). CdTe/SiO2 NPs were synthesized via the Stöber method and showed black bodies' strong absorption in a wide spectral range without excitonic emission, which made them excellent ECL quenchers. Within the effective distance of energy scavenging, the ECL quenching efficiency was dependent on the number of CdTe QDs doped into the silica NPs. Using ca. 200 CdTe QDs doped silica NPs on average of 40 nm in diameter as ECL quenching labels, attomolar detection of thrombin was successfully realized. The protein detection involves a competition binding event, based on thrombin replacing CdTe/SiO2 NPs labeled probing DNA which is hybridized with capturing aptamer immobilized on a CdS:Mn NCs film modified glassy carbon electrode surface by specific aptamer-protein affinity interactions. It results in the displacement of ECL quenching labels from CdS:Mn NCs film and concomitant ECL signal recovery. Owing to the high-content CdTe QDs in silica NP, the increment of ECL intensity (ΔIECL) and the concentration of thrombin showed a double logarithmic linear correlation in the range of 5.0 aM~5.0 fM with a detection limit of 1aM. And, the aptasensor hardly responded to antibody, bovine serum albumin (BSA), haemoglobin (Hb) and lysozyme, showing good detection selectivity for thrombin. This long-distance energy scavenging could have a promising application perspective in the detection of biological recognition events on a molecular level.This work reports an aptasensor for ultrasensitive detection of thrombin based on remarkably efficient energy-transfer induced electrochemiluminescence (ECL) quenching from CdS:Mn nanocrystals (NCs) film to CdTe QDs-doped silica nanoparticles (CdTe/SiO2 NPs). CdTe/SiO2 NPs were synthesized via the Stöber method and showed black bodies' strong absorption in a wide spectral range without excitonic emission, which made them excellent ECL quenchers. Within the effective distance of energy scavenging, the ECL quenching efficiency was dependent on the number of CdTe QDs doped into the silica NPs. Using ca. 200 CdTe QDs doped silica NPs on average of 40 nm in diameter as ECL quenching labels, attomolar detection of thrombin was successfully realized. The protein detection involves a competition binding event, based on thrombin replacing CdTe/SiO2 NPs labeled probing DNA which is hybridized with capturing aptamer immobilized on a CdS:Mn NCs film modified glassy carbon electrode surface by specific aptamer-protein affinity interactions. It results in the displacement of ECL quenching labels from CdS:Mn NCs film and concomitant ECL signal recovery. Owing to the high-content CdTe QDs in silica NP, the increment of ECL intensity (ΔIECL) and the concentration of thrombin showed a double logarithmic linear correlation in the range of 5.0 aM~5.0 fM with a detection limit of 1aM. And, the aptasensor hardly responded to antibody, bovine serum albumin (BSA), haemoglobin (Hb) and lysozyme, showing good detection selectivity for thrombin. This long-distance energy scavenging could have a promising application perspective in the detection of biological recognition events on a molecular level. Electronic supplementary information (ESI) available: TEM pictures for CdTe/SiO2 and undoped SiO2 NPs of 400 nm size are available. See DOI: 10.1039/c1nr10175g

  2. Progenitors of Recombining Supernova Remnants

    Moriya, Takashi J.

    2012-01-01

    Usual supernova remnants have either ionizing plasma or plasma in collisional ionization equilibrium, i.e., the ionization temperature is lower than or equal to the electron temperature. However, the existence of recombining supernova remnants, i.e., supernova remnants with the ionization temperature higher than the electron temperature, is recently confirmed. One suggested way to have recombining plasma in a supernova remnant is to have a dense circumstellar medium at the time of the superno...

  3. Hydrogen Recombination with Multilevel atoms

    De, Soma; Baron, E.; Peter H. Hauschildt

    2010-01-01

    Hydrogen recombination is one of the most important atomic processes in many astrophysical objects such as Type II supernova (SN~II) atmospheres, the high redshift universe during the cosmological recombination era, and H II regions in the interstellar medium. Accurate predictions of the ionization fraction can be quite different from those given by a simple solution if one takes into account many angular momentum sub-states, non-resonant processes, and calculates the rates of all atomic proc...

  4. Combinatorics in Recombinational Population Genomics

    Parida, Laxmi

    The work that I will discuss is motivated by the need for understanding, and processing, the manifestations of recombination events in chromosome sequences. In this talk, we focus on two related problems. First, we explore the very general problem of reconstructability of pedigree history. How plausible is it to unravel the history of a complete unit (chromosome) of inheritance? The second problem deals with reconstructing the recombinational history of a collection of chromosomes.

  5. Do mitochondria recombine in humans?

    Eyre-Walker, A

    2000-01-01

    Until very recently, mitochondria were thought to be clonally inherited through the maternal line in most higher animals. However, three papers published in 2000 claimed population-genetic evidence of recombination in human mitochondrial DNA. Here I review the current state of the debate. I review the evidence for the two main pathways by which recombination might occur: through paternal leakage and via a mitochondrial DNA sequence in the nuclear genome. There is no strong evidence for either...

  6. Eukaryotes arose after genetic recombination

    Stupar Milanko R.

    2006-01-01

    Full Text Available Division of ancestral prokaryotic pragenome into two circular double-stranded DNA molecules by genetic recombination, is a base for future separate evolution of nuclear and mitochondrial gene compartment. This suggests monophyletic origin of both, mitochondrion and nucleus. Presumed organism which genome undergoes genetic recombination has to be searched among an aerobic, oxygen nonproducing, archaeon with no rigid cell wall, but a plasma membrane. Plastid evolves from an aerobic, oxygen producing protoeukaryote, after mitoplastid genome duplication and subsequent functional segregation.

  7. Delayed recombination and cosmic parameters

    Current cosmological constraints from cosmic microwave background anisotropies are typically derived assuming a standard recombination scheme, however additional resonance and ionizing radiation sources can delay recombination, altering the cosmic ionization history and the cosmological inferences drawn from the cosmic microwave background data. We show that for recent observations of the cosmic microwave background anisotropy, from the Wilkinson microwave anisotropy probe satellite mission (WMAP) 5-year survey and from the arcminute cosmology bolometer array receiver experiment, additional resonance radiation is nearly degenerate with variations in the spectral index, ns, and has a marked effect on uncertainties in constraints on the Hubble constant, age of the universe, curvature and the upper bound on the neutrino mass. When a modified recombination scheme is considered, the redshift of recombination is constrained to z*=1078±11, with uncertainties in the measurement weaker by 1 order of magnitude than those obtained under the assumption of standard recombination while constraints on the shift parameter are shifted by 1σ to R=1.734±0.028. From the WMAP5 data we obtain the following constraints on the resonance and ionization sources parameters: εαi<0.058 at 95% c.l.. Although delayed recombination limits the precision of parameter estimation from the WMAP satellite, we demonstrate that this should not be the case for future, smaller angular scales measurements, such as those by the Planck satellite mission.

  8. Plasma membrane associated phospholipase C from human platelets: Synergistic stimulation of phosphatidylinositol 4,5-bisphosphate hydrolysis by thrombin and guanosine 5'-O-(3-thiotriphosphate)

    The effects of thrombin and GTPγS on the hydrolysis of phosphoinositides by membrane-associated phospholipase C (PLC) from human platelets were examined with endogenous [3H]inositol-labeled membranes or with lipid vesicles containing either [3H]phosphatidylinositol or [3H]phosphatidylinositol 4,5-bisphosphate. GTPγS (1 μM) or thrombin (1 unit/mL) did not stimulate release of inositol trisphosphate (IP3), inositol bisphosphate (IP2), or inositol phosphate (IP) from [3H]inositol-labeled membranes. IP2 and IP3, but not IP, from [3H]inositol-labeled membranes were, however, stimulated 3-fold by GTPγS (1 μM) plus thrombin (1 unit/mL). A higher concentration of GTPγS (100 μM) alone also stimulated IP2 and IP3, but not IP, release. In the presence of 1 mM calcium, release of IP2 and IP3 was increased 6-fold over basal levels; however, formation of IP was not observed. At submicromolar calcium concentration, hydrolysis of exogenous phosphatidylinositol 4,5-bisphosphate (PIP2) by platelet membrane associated PLC was also markedly enhanced by GTPγS (100 μM) or GTPγS (1 μM) plus thrombin (1 unit/mL). Under identical conditions, exogenous phosphatidylinositol (PI) was not hydrolyzed. The same substrate specificity was observed when the membrane-associated PLC was activated with 1 mM calcium. Thrombin-induced hydrolysis of PIP2 was inhibited by treatment of the membranes with pertussis toxin or pretreatment of intact platelets with 12-O-tetradecanoyl-13-acetate (TPA) prior to preparation of membranes. Pertussis toxin did not inhibit GTPγS (100 μM) or calcium (1 mM) dependent PIP2 breakdown, while TPA inhibited GTPγS-dependent but not calcium-dependent phospholipase C activity

  9. Eculizumab therapy results in rapid and sustained decreases in markers of thrombin generation and inflammation in patients with PNH independent of its effects on hemolysis and microparticle formation.

    Weitz, Ilene C; Razavi, Pedram; Rochanda, Leanne; Zwicker, Jeffrey; Furie, Bruce; Manly, David; Mackman, Nigel; Green, Ralph; Liebman, Howard A

    2012-09-01

    Paroxysmal Nocturnal Hemoglobinuria (PNH) is a clonal bone marrow disorder which results in the loss of glycosylphosphatidyl inositol (GPI) anchors from cell membranes. As a consequence, membrane inhibitors of complement are lost rendering the cells more susceptible to complement mediated destruction. This results in hemolysis, leukopenia, thrombocytopenia and thrombophilia. Eculizumab, a monoclonal antibody to complement protein 5, has been approved for the treatment of PNH and is associated with a significant reduction in hemolysis, thromboembolic events and fatigue. We prospectively studied the effect of Eculizumab therapy on plasma markers of thrombin generation (D-Dimers, TAT), inflammation (IL-6), soluble P-selectin (sP-selectin), antigenic (TFMP) and functional (fTFMP) tissue factor bearing microparticles and total plasma microparticle ex vivo factor Xa generation (MPFXa) in eleven Eculizumab naive PNH patients. Blood sampling occurred day 1, prior to Eculizumab treatment, then on days 8,15,22,29, 43, 90. Our results demonstrate a statistically significant reduction in D-Dimer, TAT, IL-6, sP-selectin, and TFMP during the induction phase of treatment (day 1-29) which was sustained during the maintenance treatment (day 29-90). Although the serum LDH levels decreased rapidly, there was no correlation between the change in LDH and the markers of thrombin generation and inflammation. Although there was a statistically significant decrease in TFMP, this decrease did not correlate with changes in markers of thrombin generation or inflammation. Ex vivo MPFXa generation did not decrease with Eculizumab treatment suggesting continued microparticle formation despite inhibition of hemolysis. Ex vivo total microparticle FXa generation was found to have an inverse correlation with markers of thrombin generation, suggesting that in PNH patients in vivo thrombin generation occurs by a pathway independent of hemolysis and microparticle generation. PMID:22542362

  10. Topics in commutative ring theory

    Watkins, John J

    2009-01-01

    Topics in Commutative Ring Theory is a textbook for advanced undergraduate students as well as graduate students and mathematicians seeking an accessible introduction to this fascinating area of abstract algebra. Commutative ring theory arose more than a century ago to address questions in geometry and number theory. A commutative ring is a set-such as the integers, complex numbers, or polynomials with real coefficients--with two operations, addition and multiplication. Starting from this simple definition, John Watkins guides readers from basic concepts to Noetherian rings-one of

  11. Modern topics in electron scattering

    Frois, Bernard

    1991-01-01

    This book summarizes the considerable progress recently achieved in the understanding of nucleon and nuclear structure by using high energy electrons as a probe. A collection of papers discusses in detail the new frontiers of this field. Experimental and theoretical articles cover topics such as the structure of the nucleon, nucleon distributions, many-body correlations, non-nucleonic degrees of freedom and few-body systems. This book is an up-to-date introduction to the research planned with continuous beam electron accelerators.

  12. Radioiodination and biodistribution study of a thrombin-like enzyme/gyroxin from Lachesis muta muta venom

    Pujatti, Priscilla Brunelli; Soares, Marcella Araugio; Silva, Paulo R.O.; Santos, Raquel Gouvea dos [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)]. E-mail: priscillapujatti@yahoo.com.br; Magalhaes, Henrique P.B. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Faculdade de Farmacia

    2007-07-01

    Recently, our group isolated and sequenced a thrombin-like enzyme (TLE) of 40kDa from the snake Lachesis muta muta. This protein hydrolyses synthetic substrates with specificity similar to that of trypsin and may be involved in the haemorrhagic, proteolytic and blood-clotting activities of the Lachesis venom. When injected into the tail veins of mice at levels of 0.015-0.130{mu}g/g mouse, the TLE induce temporary episodes of opisthotonus and rapid rolling around the long axis of the animals and that is the reason why it is also called gyroxin. If this gyroxin activity is caused by direct interaction with the brain or by indirect effect remains to be investigated. We report in this work the radioiodination of TLE and the biodistribution of I-TLE in order to investigate its pharmacokinetics and verify if this enzyme are able to penetrate the blood brain barrier to evoke directly the gyroxin effects. (author)

  13. Radioiodination and biodistribution study of a thrombin-like enzyme/gyroxin from Lachesis muta muta venom

    Recently, our group isolated and sequenced a thrombin-like enzyme (TLE) of 40kDa from the snake Lachesis muta muta. This protein hydrolyses synthetic substrates with specificity similar to that of trypsin and may be involved in the haemorrhagic, proteolytic and blood-clotting activities of the Lachesis venom. When injected into the tail veins of mice at levels of 0.015-0.130μg/g mouse, the TLE induce temporary episodes of opisthotonus and rapid rolling around the long axis of the animals and that is the reason why it is also called gyroxin. If this gyroxin activity is caused by direct interaction with the brain or by indirect effect remains to be investigated. We report in this work the radioiodination of TLE and the biodistribution of I-TLE in order to investigate its pharmacokinetics and verify if this enzyme are able to penetrate the blood brain barrier to evoke directly the gyroxin effects. (author)

  14. Synthesis of Fluorescent Potassium Ion-Sensing Probes Based on a Thrombin-Binding DNA Aptamer-Peptide Conjugate.

    Takenaka, Shigeori

    2015-01-01

    This unit provides a procedure for synthesis of the potassium-sensing peptide-oligodeoxyribonucleotide conjugate PSO-5 for visualizing potassium ions (K(+) ) in living cells. It is constructed by combining an oligodeoxyribonucleotide carrying a thrombin-binding DNA aptamer (TBA) sequence with an uncharged peptide carrying biotin and the fluorescence tags fluorescein (FAM) and tetramethylrhodamine (TAMRA). The PSO-5 and biotin-modified nuclear export signal peptide are conjugated through streptavidin, and this sensing molecule is introduced into the cell where it is localized in the cytoplasm. The TBA part of PSO-5 shows a conformational change from a random coil to a tetraplex structure induced by K(+) and a change in the fluorescence resonance energy transfer (FRET) efficiency between FAM and TAMRA arising from its conformational change, enabling fluorometric detection of changes in K(+) concentration. 2015 by John Wiley & Sons, Inc. PMID:26380906

  15. A multifunctional hemin@metal-organic framework and its application to construct an electrochemical aptasensor for thrombin detection

    Xie, Shunbi; Ye, Jiawei; Yuan, Yali; Chai, Yaqin; Yuan, Ruo

    2015-10-01

    A new type of multifunctional metal-organic framework (MOF) has been synthesized by encapsulating hemin into the nano-sized Fe-MIL-88 MOFs (hemin@MOFs) and first applied in an electrochemical aptasensor to detect thrombin (TB) with the aid of an enzyme for signal amplification. The gold nanoparticle functionalized hemin@MOFs (Au/hemin@MOFs) have not only simultaneously served as redox mediators and solid electrocatalysts, but have also been utilized as an ideal loading platform to immobilize a large number of biomolecules. In this aptasensor, Au/hemin@MOFs conjugated with glucose oxidase (GOD) and thrombin binding aptamer (TBA II) were used as the secondary aptamer bioconjugates (Au/hemin@MOF-TBA II-GOD bioconjugates), and TB was sandwiched between Au/hemin@MOF-TBA II-GOD bioconjugates and the amino-terminated TBA I which was self-assembled on the gold nanoparticle (AuNP) modified electrode. The GOD could oxidize glucose into gluconic acid accompanied by the generation of H2O2. The generated H2O2 on the electrode surface was further electrocatalyzed by hemin@MOFs to amplify the electrochemical signal of hemin contained in hemin@MOFs. Therefore, the synthesized hemin@MOFs represented a new paradigm for multifunctional materials since it combined three different functions including serving as catalysts, redox mediators and loading platforms within a single material. With such an ingenious design, a wide linear range of 0.0001 nM to 30 nM was acquired with a relatively low detection limit of 0.068 pM for TB detection.A new type of multifunctional metal-organic framework (MOF) has been synthesized by encapsulating hemin into the nano-sized Fe-MIL-88 MOFs (hemin@MOFs) and first applied in an electrochemical aptasensor to detect thrombin (TB) with the aid of an enzyme for signal amplification. The gold nanoparticle functionalized hemin@MOFs (Au/hemin@MOFs) have not only simultaneously served as redox mediators and solid electrocatalysts, but have also been utilized as an ideal loading platform to immobilize a large number of biomolecules. In this aptasensor, Au/hemin@MOFs conjugated with glucose oxidase (GOD) and thrombin binding aptamer (TBA II) were used as the secondary aptamer bioconjugates (Au/hemin@MOF-TBA II-GOD bioconjugates), and TB was sandwiched between Au/hemin@MOF-TBA II-GOD bioconjugates and the amino-terminated TBA I which was self-assembled on the gold nanoparticle (AuNP) modified electrode. The GOD could oxidize glucose into gluconic acid accompanied by the generation of H2O2. The generated H2O2 on the electrode surface was further electrocatalyzed by hemin@MOFs to amplify the electrochemical signal of hemin contained in hemin@MOFs. Therefore, the synthesized hemin@MOFs represented a new paradigm for multifunctional materials since it combined three different functions including serving as catalysts, redox mediators and loading platforms within a single material. With such an ingenious design, a wide linear range of 0.0001 nM to 30 nM was acquired with a relatively low detection limit of 0.068 pM for TB detection. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr04532k

  16. Current topics in nail surgery

    Alam; Scher

    1999-10-01

    BACKGROUND: Nail surgery can be performed in an office-based dermatology practice with a limited amount of specialized equipment and training. Several excellent reviews have been published in recent years that detail the techniques of nail surgery for both the novice and the experienced practitioner. OBJECTIVE: In this article recent developments in nail surgery are discussed. Topics that are treated include the general principles of nail surgery, including epidemiologic issues, studies of nail anatomy, instrumentation, and anesthesia. The reconstruction of injuries and congenital defects involving the nail is explained, and the role of the hand surgeon clarified. Appropriate removal of tumours and cysts is considered, with special attention to the management of malignant lesions. The controversy regarding more or less conservative management of melanonychia striata is addressed, and the need for early diagnosis of subungual melanoma is emphasized. Other topics are surgical management of ingrown nails and onychomycosis. Newer areas of nail surgery, such as laser surgery of the nail, psychodermatology of the nail, and the role of primary care physicians in simple nail surgery are also examined. PMID:10575165

  17. Haemophilia B caused by mutation of a potential thrombin cleavage site in factor IX

    Winship, P.R. (Univ. of Oxford (England))

    1990-03-11

    Haemophilia B is a blood coagulation disorder caused by mutations in the factor IX gene giving functionally defective or reduced levels of factor IX protein circulating in the plasma. The mutation in the Caucasian patient under investigation, Haemophilia B Oxford h5 (Oxh5), was characterized at the DNA level by constructing a genomic library using leucocyte-derived DNA from the patient. Overlapping recombinant clones spanning the entire factor IX locus were isolated which then allowed the generation of a series of sub-clones across all eight exons (a-h) plus the 5{prime} and 3{prime} flanking sequences known to be important in regulation of the gene and polyadenylation of the mRNA species.

  18. Recombining WMAP: Constraints on ionizing and resonance radiation at recombination

    We place new constraints on sources of ionizing and resonance radiation at the epoch of the recombination process using the recent cosmic microwave background temperature and polarization spectra coming from the Wilkinson Microwave Anisotropy Probe (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 such as the spectral index ns and its running. Physically motivated models, such as those based on primordial black holes 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

  19. On-line Hot Topic Recommendation Using Tolerance Rough Set Based Topic Clustering

    Yonghui Wu

    2010-04-01

    Full Text Available In this paper we present our research of online hot topic detection and label extraction method for our hot topic recommendation system. Using a new topical feature selection method, the feature space is compressed suitable for an online system. The tolerance rough set model is used to enriching the small set of topical feature words to a topical approximation space. According to the distance defined on the topical approximation space, the web pages are clustered into groups which will be merged with document overlap. The topic labels are extracted based on the approximation topical space enriched with the useful but high frequency topical words dropped by the clustering process. The experiments show that our method could generate more information abundant classes and more topical class labels, alleviate the topical drift caused by the non-topical and noise words.

  20. Human-competitive automatic topic indexing

    Medelyan, Olena

    2009-01-01

    Topic indexing is the task of identifying the main topics covered by a document. These are useful for many purposes: as subject headings in libraries, as keywords in academic publications and as tags on the web. Knowing a document’s topics helps people judge its relevance quickly. However, assigning topics manually is labor intensive. This thesis shows how to generate them automatically in a way that competes with human performance. Three kinds of indexing are investigated: term assignment, a task commonly performed by librarians, who select topics from a controlled vocabulary; tagging, a popular activity of web users, who choose topics freely; and a new method of keyphrase extraction, where topics are equated to Wikipedia article names. A general two-stage algorithm is introduced that first selects candidate topics and then ranks them by significance based on their properties. These properties draw on statistical, semantic, domain-specific and encyclopedic knowledge. They are combined using a machine learn...

  1. Topical Pain Relievers May Cause Burns

    ... Consumers Consumer Updates Topical Pain Relievers May Cause Burns Share Tweet Linkedin Pin it More sharing options ... rare, have ranged from mild to severe chemical burns with use of such brand-name topical muscle ...

  2. Synergetics introduction and advanced topics

    Haken, Hermann

    2004-01-01

    This book is an often-requested reprint of two classic texts by H. Haken: "Synergetics. An Introduction" and "Advanced Synergetics". Synergetics, an interdisciplinary research program initiated by H. Haken in 1969, deals with the systematic and methodological approach to the rapidly growing field of complexity. Going well beyond qualitative analogies between complex systems in fields as diverse as physics, chemistry, biology, sociology and economics, Synergetics uses tools from theoretical physics and mathematics to construct an unifying framework within which quantitative descriptions of complex, self-organizing systems can be made. This may well explain the timelessness of H. Haken's original texts on this topic, which are now recognized as landmarks in the field of complex systems. They provide both the beginning graduate student and the seasoned researcher with solid knowledge of the basic concepts and mathematical tools. Moreover, they admirably convey the spirit of the pioneering work by the founder of ...

  3. Topical immunotherapy in alopecia areata.

    Singh, Gurcharan; Lavanya, Ms

    2010-01-01

    Alopecia Areata (AA) is a common non-scarring alopecia directed against the anagenic hair follicle. Various treatment modalities have been used for the treatment of severe AA. Topical immunotherapy is the best documented treatment so far for severe and refractory AA. Dinitrochlorobenzene (DNCB), squaric acid dibutylester (SADBE), and diphencyprone (DPCP) are the contact allergens used for this purpose. DNCB has been found to be mutagenic by the Ames test and is largely replaced by DPCP and SADBE. DPCP and SADBE are both known to be non-mutagenic compounds and have comparable efficacy results and relapse rates. SADBE requires special solvents and additives to maintain its potency and is more expensive than the rest. DPCP has a response rate varying from 60% in severe Alopecia Areata to 17% in patients with alopecia totalis or universalis, and shows about 88 to 100% high response rate in patients with patchy Alopecia Areata. PMID:21188022

  4. KEY TOPICS IN SPORTS MEDICINE

    Amir Ali Narvani

    2006-12-01

    Full Text Available Key Topics in Sports Medicine is a single quick reference source for sports and exercise medicine. It presents the essential information from across relevant topic areas, and includes both the core and emerging issues in this rapidly developing field. It covers: 1 Sports injuries, rehabilitation and injury prevention, 2 Exercise physiology, fitness testing and training, 3 Drugs in sport, 4 Exercise and health promotion, 5 Sport and exercise for special and clinical populations, 6 The psychology of performance and injury. PURPOSE The Key Topics format provides extensive, concise information in an accessible, easy-to-follow manner. AUDIENCE The book is targeted the students and specialists in sports medicine and rehabilitation, athletic training, physiotherapy and orthopaedic surgery. The editors are authorities in their respective fields and this handbook depends on their extensive experience and knowledge accumulated over the years. FEATURES The book contains the information for clinical guidance, rapid access to concise details and facts. It is composed of 99 topics which present the information in an order that is considered logical and progressive as in most texts. Chapter headings are: 1. Functional Anatomy, 2. Training Principles / Development of Strength and Power, 3. Biomechanical Principles, 4. Biomechanical Analysis, 5. Physiology of Training, 6. Monitoring of Training Progress, 7. Nutrition, 8. Hot and Cold Climates, 9. Altitude, 10. Sport and Travelling, 11. Principles of Sport Injury Diagnosis, 12. Principles of Sport and Soft Tissue Management, 13. Principles of Physical Therapy and Rehabilitation, 14. Principles of Sport Injury Prevention, 15. Sports Psychology, 16. Team Sports, 17. Psychological Aspects of Injury in Sport, 18. Injury Repair Process, 19. Basic Biomechanics of Tissue Injury, 20. Plain Film Radiography in Sport, 21. Nuclear Medicine, 22. Diagnostic Ultrasound, 23. MRI Scan, 24. Other Imaging, 5. Head Injury, 26. Eye Injury, 27. Injury to the Face, Nose, Ear, 28. Dental Problems, 29. Protective Headwear and Facial Protection in Sport, 30. Spinal Injury: Functional Anatomy and General Biomechanics, 31. Cervical Spine Injuries, 32. Thoracolumbar Spine Injuries, 33. Spine Related Syndromes, 34. Chest Injuries, 35. Abdominal Injuries and Abdominal Wall Injuries, 36. Urinary Tract Injuries, 37. The Shoulder Disorders, 38. Acromioclavicular Joint Disorders, 39. The Elbow Joint, 40. The Forearm and Wrist, 41. Hand Injuries, 42. Neurological Injury Affecting the Upper Limb, 43. Buttock Pain, 44. Groin Pain, 45. Thigh Injuries. ASSESSMENT Based on graduate programme teaching practice and with an international team of contributors, this is a valuable and practical resource for all those interested in sports and exercise medicine, including sports clinicians, general practitioners, team doctors, orthopaedic surgeons, accident and emergency doctors and physiotherapists. It is concise and well organized in its presentation, creating an effective textbook. I believe, therefore, the book will serve as a first-rate teaching tool and reference for students and specialists in sports medicine and rehabilitation, athletic training, physiotherapy. Students will enjoy the format of this book

  5. Topics in combinatorial pattern matching

    Vildhøj, Hjalte Wedel

    our second trade-off is nearly optimal. Fingerprints in Compressed Strings. The Karp-Rabin fingerprint of a string is a type of hash value that due to its strong properties has been used in many string algorithms. We show how to construct a data structure for a string S of size N compressed by a......This dissertation studies problems in the general theme of combinatorial pattern matching. More specifically, we study the following topics: Longest Common Extensions. We revisit the longest common extension (LCE) problem, that is, preprocess a string T into a compact data structure that supports...... computational bottleneck, including approximate string matching and computing palindromes. We also present an efficient technique to reduce LCE queries on two strings to one string. Finally, we give a lower bound on the time-space product for LCE data structures in the non-uniform cell probe model showing that...

  6. Topics in computational linear optimization

    Hultberg, Tim Helge

    2000-01-01

    of high quality solvers and the use of algebraic modelling systems to handle the communication between the modeller and the solver. This dissertation features four topics in computational linear optimization: A) automatic reformulation of mixed 0/1 linear programs, B) direct solution of sparse...... factorization of an augmented system is computed. This involves the solution of a sparse triangular system with 's' right-hand sides. Solution sparsity is exploited in the sparse triangular solves of the block LU factorization. 3) a factorization of the Schur complement matrix, of order 's', is computed. The...... of a solution algorithm are incorporated as important parts of most LP solvers. The usual LP reduction techniques require a very limited effort but nevertheless often result in substantial reductions. One of the reasons for this good performance is the way LP models are typically formulated using...

  7. Conclusion from the fifth topic

    The topic ''mechanics and alteration kinetics of glasses'' is a crucial point for the understanding of the long-term behaviour of nuclear glasses. Kinetic models used in simulation are based on the works made by Grambow who imputes the control of the alteration kinetics of borosilicate glasses to the desorption of the ortho-silica acid produced at the reactive interface. The ensuing kinetics law requires the existence of an equilibrium of the silica at the interface glass/gel and the existence of a linear concentration gradient dissolved in the interstitial gel solution. The role of the gel needs further studies to be well understood. The difficulty lies in the fact that the composition and the structure of the gel varies with time, space (anisotropy) and with the conditions of alteration (temperature, pH, flowrate...). (A.C.)

  8. Current topics in radiation measurements

    Current research topics in radiation measurements will be shown in this presentation. Applications of radiation measurements have grown with the development of radiation sources and new measurement techniques. Recent new developments in this field are briefly introduced. Optical techniques such as lasers and fiber optics, which are widely used in an optical communication field, are successfully applied to radiation measurements. Micro-fabrication techniques and the photolithography technique are indispensable for semiconductor or even gas detectors. Complicated analog signal processing is being simplified by the use of fast computation techniques available in digital chips. Cryogenic X-ray detectors are making a great progress in the energy resolution. Some of the current research topics found in the recent journals and international symposiums are as follows: the development of room temperature semiconductor radiation detectors like CdZnTe and SiC, new signal processing methods such as coplanar grid unipolar charge sensing, medical γ-ray imaging, the development of cryogenic X-ray detectors such as STJs (Superconducting Tunnel Junction) and TES (Transition Edge Sensor) microcalorimeters, micromachined gas proportional counters like MSGC/MGC/GEM, new detection system which requires both the energy and spatial resolutions, the search of longer wavelength scintillators, development of new fast scintillators such as LSO/YAP/LuAP, new digital waveform processing based on fast digitizing technique, etc. Current developments are especially focused on the increase of the information derived from the detector and the improvement in the resolution. One of the other directions of the development is toward the microscopic visualization of the radiation. Such an approach must solve many technological difficulties both in fabrication of the detectors and even in the detection scheme, however, we might proceed to open a new phase of radiation measurements soon. (author)

  9. On-line Hot Topic Recommendation Using Tolerance Rough Set Based Topic Clustering

    Yonghui Wu; Yuxin Ding; Xiaolong Wang; Jun Xu

    2010-01-01

    In this paper we present our research of online hot topic detection and label extraction method for our hot topic recommendation system. Using a new topical feature selection method, the feature space is compressed suitable for an online system. The tolerance rough set model is used to enriching the small set of topical feature words to a topical approximation space. According to the distance defined on the topical approximation space, the web pages are clustered into groups which will be mer...

  10. Topical tacrolimus as treatment of atopic dermatitis

    Masutaka Furue; Satoshi Takeuchi

    2009-01-01

    Masutaka Furue, Satoshi TakeuchiDepartment of Dermatology, Faculty of Medical Sciences, Kyushu University, Fukuoka, JapanAbstract: Atopic dermatitis (AD) is a common, chronic, relapsing, severely pruritic, eczematous skin disease. The mainstays of treatment for AD are topical tacrolimus and topical steroids. Tacrolimus, a calcineurin inhibitor, not only complements existing treatment options but also overcomes some of the drawbacks of topical steroid therapy when given topically and thus meet...

  11. Topical report review status: Volume 10

    NONE

    1996-03-01

    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 by the NRC. This report is published annually.

  12. Effects of Preexamination Disclosure of Essay Topics.

    Powers, Donald E.; Fowles, Mary E.

    1998-01-01

    To determine the effects on test performance and test validity of releasing essay topics before an examination, 300 prospective graduate students wrote essays on a released and an unreleased topic. Analyses did not reveal any statistically significant effect of topic release. (SLD)

  13. Inhomogeneous recombinations during cosmic reionization

    Sobacchi, Emanuele

    2014-01-01

    By depleting the ionizing photon budget available to expand cosmic HII regions, recombining systems (or Lyman limit systems) can have a large impact during (and following) cosmic reionization. Unfortunately, directly resolving such structures in large-scale reionization simulations is computationally impractical. Instead, here we implement a sub-grid prescription for tracking inhomogeneous recombinations in the intergalactic medium. Building on previous work parameterizing photo-heating feedback on star-formation, we present large-scale, semi-numeric reionization simulations which self-consistently track the local (sub-grid) evolution of both sources and sinks of ionizing photons. Our simple, single-parameter model naturally results in both an extended reionization and a modest, slowly-evolving emissivity, consistent with observations. Recombinations are instrumental in slowing the growth of large HII regions, and damping the rapid rise of the ionizing background in the late stages of (and following) reioniza...

  14. Dissociative recombination of protonated methanol

    Geppert, Wolf; Hamberg, Mathias; Thomas, Richard D; Österdahl, Fabian; Hellberg, Fredrik; Zhaunerchyk, Vitali; Ehlerding, Anneli; Millar, Tom; Roberts, Helen; Semaniak, Jacek; af Ugglas, Magnus; Källberg, Anders; Simonsson, Ansgar; Kaminska, Magdalena; Larsson, Mats

    2006-01-01

    The branching ratios of the different reaction pathways and the overall rate coefficients of the dissociative recombination reactions of CH3OH2+ and CD3OD2+ have been measured at the CRYRING storage ring located in Stockholm, Sweden. Analysis of the data yielded the result that formation of methanol or deuterated methanol accounted for only 3 and 6% of the total rate in CH3OH2+ and CD3OD2+, respectively. Dissociative recombination of both isotopomeres mainly involves fragmentation of the C–O ...

  15. Selenium incorporation using recombinant techniques

    An overview of techniques for recombinant incorporation of selenium and subsequent purification and crystallization of the resulting labelled protein. Using selenomethionine to phase macromolecular structures is common practice in structure determination, along with the use of selenocysteine. Selenium is consequently the most commonly used heavy atom for MAD. In addition to the well established recombinant techniques for the incorporation of selenium in prokaryal expression systems, there have been recent advances in selenium labelling in eukaryal expression, which will be discussed. Tips and things to consider for the purification and crystallization of seleno-labelled proteins are also included

  16. [Skin aging and evidence-based topical strategies].

    Bayerl, C

    2016-02-01

    Anti-aging in dermatology primarily focuses on the prevention of skin aging with UV protection (clothing and sunsceens), free radical scavengers (synthetic or botanic), and cell-protecting agents such as vitaminB3. For the correction of signs of early skin aging, retinoic acid derivatives in dermatological prescriptions are the best studied substances. Topical hormonal prescriptions are also an option if UV damage has not been the leading culprit for aging. Chemical peeling leads to a marked increase in collagen formation, the deaper the better. Ingredients in cream preparations can reduce superficial skin folds (polyphenols, amino acid peptides). Modulators of regular pigmentation are important for anti-aging preparations. Growth factors (plant extracts, recombinant growth factors) are not thoroughly studied regarding the cost-benefit and risk ratio. Complex precedures such as photodynamic therapy have an impact on the appearance of aged skin. PMID:26683808

  17. Topical subjects of nuclear energy

    The controversy as regards the introduction of nuclear energy to the energy supply of the Federal Republic of Germany has not subdued yet. However, the discussion has shifted from technical questions more to the field of political argumentation. In addition, questions concerning the back end cycle have come to the fore. The report at hand deals with the topical subjects of fuel reprocessing, ultimate storage of radioactive wastes, the impact of power plants in general and nuclear power plants in particular on the climate, safety and safeguard questions concerning nuclear facilities and fissionable materials, and with the properties and possibilities of plutonium. The authors tried to present technical know-how in an easy comprehensible way. Literature references enable the checking of facts and provide the possibility to deal in more detail with the matter. The seminar report is to give all those interested the opportunity to acquaint themselves with facts and know-how and to acquire knowledge on which to base a personal opinion. (orig.)

  18. Decision Point 1 Topical Report

    Yablonsky, Al; Barsoumian, Shant; Legere, David

    2013-05-01

    This Topical Report addresses accomplishments achieved during Phase 2a of the SkyMine® Carbon Mineralization Pilot Project. The primary objectives of this project are to design, construct, and operate a system to capture CO2 from a slipstream of flue gas from a commercial coal-fired cement kiln, convert that CO2 to products having commercial value (i.e., beneficial use), show the economic viability of the CO2 capture and conversion process, and thereby advance the technology to the point of readiness for commercial scale demonstration and proliferation. The overall process is carbon negative, resulting in mineralization of CO2 that would otherwise be released into the atmosphere. The project will also substantiate market opportunities for the technology by sales of chemicals into existing markets, and identify opportunities to improve technology performance and reduce costs at the commercial scale. The project is being conducted in two phases. The primary objectives of Phase 1 were to elaborate proven SkyMine® process chemistry to commercial pilot-scale operation and complete the preliminary design for the pilot plant to be built and operated in Phase 2, complete a NEPA evaluation, and develop a comprehensive carbon life cycle analysis. The objective of the current Phase (2a) is to complete the detailed design of the pilot plant to be built in Phase 2b.

  19. Two Topics In String Theory

    Cheung, Y E

    2000-01-01

    We study two topics in string theory: consistency of D- branes and their intersections in topologically nontrivial background, and Noncommutative Geometry and “Little String Theories.” When a D-brane wraps around a cycle of a curved manifold, the nontrivial topology of its normal bundle can induce chiral asymmetry in its worldvolume theory. We obtain the general form of the resulting anomalies for D-branes and their intersections. They are not cancelled among themselves, and the standard inflow mechanism does not apply at first sight because of their apparent lack of factorizability and the apparent vanishing of the corresponding inflow. We show, however, that after taking into consideration the effects of the twisting of the normal bundles, the anomalies can be transformed into factorized forms and precisely cancelled by finite inflow from the Chern-Simons actions for the D-branes as long as the latter are well defined. Such twisting of the normal bundle is shown to induce Ramond-Ramond c...

  20. Main technical topics in 1999

    This Safety Authority annual report strives to present current organizational provisions and future trends in nuclear safety supervision in France and to describe the most outstanding occurrences during the past year. A first part presents nine documents concerning the main topics of 1999: aging of nuclear installations, the Offsite Emergency Plans (PPI), the impact of nuclear activities on man and the environment, the criticality hazards, EDF in 1999, the EPR project, the Andra in 1999, the transport incidents, the nuclear safety in eastern Europe. The second part presents the missions and actions of the Nuclear Installations Safety in the domains of the liabilities, the organization of the nuclear safety control, the regulations of the INB, the public information, the international relations, the crisis management, the radioactive materials transportation, the radioactive wastes. The equipment, the radiation protection and the exploitation of the pressurized water reactors are also treated just as the experimental reactors, the fuel cycle installations and the the nuclear installations dismantling. (A.L.B.)

  1. Topics in Number Theory Conference

    Andrews, George; Ono, Ken

    1999-01-01

    From July 31 through August 3,1997, the Pennsylvania State University hosted the Topics in Number Theory Conference. The conference was organized by Ken Ono and myself. By writing the preface, I am afforded the opportunity to express my gratitude to Ken for beng the inspiring and driving force behind the whole conference. Without his energy, enthusiasm and skill the entire event would never have occurred. We are extremely grateful to the sponsors of the conference: The National Sci­ ence Foundation, The Penn State Conference Center and the Penn State Depart­ ment of Mathematics. The object in this conference was to provide a variety of presentations giving a current picture of recent, significant work in number theory. There were eight plenary lectures: H. Darmon (McGill University), "Non-vanishing of L-functions and their derivatives modulo p. " A. Granville (University of Georgia), "Mean values of multiplicative functions. " C. Pomerance (University of Georgia), "Recent results in primality testing. " C. ...

  2. Topics in theoretical surface science

    The energetics and structures of clean and adsorbate covered surfaces are investigated in this dissertation. First, the formalism, within the Corrected Effective Medium (CEM) method, for calculating the surface energy of a clean surface is derived. The surface energies for many different metals and their low index surfaces are presented. The minimization of the surface energy is then used to predict the multilayer relaxation of the Al(111), (100), Ni(100), (110) and Fe(100) surfaces. Extensions of the surface CEM formalism to calculate the binding energies of ordered adsorbates on metals surfaces are also derived. The minimization of the binding energy allowed determination of the binding heights, sites and the extent of induced multilayer relaxation for H and N atoms on the Fe(110), (100) and W(110) surfaces. The last topic deals with the dynamics of the epitaxial growth of metals on metal surfaces. The CEM method was first modified by making approximations to enable faster evaluations of the potential and its corresponding forces for molecular dynamics simulations. The goal of these simulations was to identify the important steps in the formation of equilibrium epitaxial structures. 180 refs., 31 figs., 18 tabs

  3. The Virtual Robotics Laboratory; TOPICAL

    The growth of the Internet has provided a unique opportunity to expand research collaborations between industry, universities, and the national laboratories. The Virtual Robotics Laboratory (VRL) is an innovative program at Oak Ridge National Laboratory (ORNL) that is focusing on the issues related to collaborative research through controlled access of laboratory equipment using the World Wide Web. The VRL will provide different levels of access to selected ORNL laboratory secondary education programs. In the past, the ORNL Robotics and Process Systems Division has developed state-of-the-art robotic systems for the Army, NASA, Department of Energy, Department of Defense, as well as many other clients. After proof of concept, many of these systems sit dormant in the laboratories. This is not out of completion of all possible research topics. but from completion of contracts and generation of new programs. In the past, a number of visiting professors have used this equipment for their own research. However, this requires that the professor, and possibly his/her students, spend extended periods at the laboratory facility. In addition, only a very exclusive group of faculty can gain access to the laboratory and hardware. The VRL is a tool that enables extended collaborative efforts without regard to geographic limitations

  4. [Current topics in pediatric nutrition].

    Morali, A; Vidailhet, M

    2002-07-01

    As main current topics in pediatric nutrition we have considered the results of the continuing research on the long term consequences of fetal malnutrition and intra-uterine growth retardation with the concept of metabolic imprinting leading to chronic disease in adulthood, the progresses of knowledge in the fields of iron metabolism and regulatory mechanisms of satiety, hunger and energetic balance, a better determination of recommended docosahexanoic and arachidonic acids intake in the first months of life for premature and term infants, and the studies on probiotics and prebiotics utilization for preventive and curative purposes. The concerns about vitamin D insufficiency in France have markedly decreased with the generalization ten years ago of cholecalciferol supplementation of infant formula, and more recently the authorization of dairy products supplementation. On the contrary the problem of iron deficiency in young children remains, as well as two major nutritional concerns: the very low percentage of breast-fed infants and the dramatic increase of childhood obesity which affects presently 14% of 10 year old children versus 5% in 1980. PMID:12162162

  5. Identifying Topics in Microblogs Using Wikipedia.

    Yıldırım, Ahmet; Üsküdarlı, Suzan; Özgür, Arzucan

    2016-01-01

    Twitter is an extremely high volume platform for user generated contributions regarding any topic. The wealth of content created at real-time in massive quantities calls for automated approaches to identify the topics of the contributions. Such topics can be utilized in numerous ways, such as public opinion mining, marketing, entertainment, and disaster management. Towards this end, approaches to relate single or partial posts to knowledge base items have been proposed. However, in microblogging systems like Twitter, topics emerge from the culmination of a large number of contributions. Therefore, identifying topics based on collections of posts, where individual posts contribute to some aspect of the greater topic is necessary. Models, such as Latent Dirichlet Allocation (LDA), propose algorithms for relating collections of posts to sets of keywords that represent underlying topics. In these approaches, figuring out what the specific topic(s) the keyword sets represent remains as a separate task. Another issue in topic detection is the scope, which is often limited to specific domain, such as health. This work proposes an approach for identifying domain-independent specific topics related to sets of posts. In this approach, individual posts are processed and then aggregated to identify key tokens, which are then mapped to specific topics. Wikipedia article titles are selected to represent topics, since they are up to date, user-generated, sophisticated articles that span topics of human interest. This paper describes the proposed approach, a prototype implementation, and a case study based on data gathered during the heavily contributed periods corresponding to the four US election debates in 2012. The manually evaluated results (0.96 precision) and other observations from the study are discussed in detail. PMID:26991442

  6. Identifying Topics in Microblogs Using Wikipedia

    Yıldırım, Ahmet; Üsküdarlı, Suzan; Özgür, Arzucan

    2016-01-01

    Twitter is an extremely high volume platform for user generated contributions regarding any topic. The wealth of content created at real-time in massive quantities calls for automated approaches to identify the topics of the contributions. Such topics can be utilized in numerous ways, such as public opinion mining, marketing, entertainment, and disaster management. Towards this end, approaches to relate single or partial posts to knowledge base items have been proposed. However, in microblogging systems like Twitter, topics emerge from the culmination of a large number of contributions. Therefore, identifying topics based on collections of posts, where individual posts contribute to some aspect of the greater topic is necessary. Models, such as Latent Dirichlet Allocation (LDA), propose algorithms for relating collections of posts to sets of keywords that represent underlying topics. In these approaches, figuring out what the specific topic(s) the keyword sets represent remains as a separate task. Another issue in topic detection is the scope, which is often limited to specific domain, such as health. This work proposes an approach for identifying domain-independent specific topics related to sets of posts. In this approach, individual posts are processed and then aggregated to identify key tokens, which are then mapped to specific topics. Wikipedia article titles are selected to represent topics, since they are up to date, user-generated, sophisticated articles that span topics of human interest. This paper describes the proposed approach, a prototype implementation, and a case study based on data gathered during the heavily contributed periods corresponding to the four US election debates in 2012. The manually evaluated results (0.96 precision) and other observations from the study are discussed in detail. PMID:26991442

  7. Turn-on near-infrared electrochemiluminescence sensing of thrombin based on resonance energy transfer between CdTe/CdS coresmall/shellthick quantum dots and gold nanorods.

    Wang, Jing; Jiang, Xiaochun; Han, Heyou

    2016-08-15

    Here we designed a near-infrared electrochemiluminescence (NECL) aptasensor for turn-on ultrasensitive determination of thrombin. It was based on the ECL resonance energy transfer (ECL-RET) of CdTe/CdS coresmall/shellthick quantum dots (QDs) to gold nanorods (AuNRs). AuNRs which functioned as ECL acceptors were assembled onto CdTe/CdS film by DNA hybridization between aptamers and their complementary oligonucleotides. In the absence of thrombin, the NECL of QDs was quenched as a result of the ECL-RET of QDs to AuNRs. In the presence of thrombin, the NECL of the system was "turned on" because thrombin can replace the AuNRs onto the QDs film, owing to the specific aptamer-protein affinity interactions. In this way, the increment of ECL intensity and the concentration of thrombin showed a logarithmic linear correlation in the range of 100 aM to 10 fM with a detection limit of 31 aM (S/N=3). Importantly, the developed aptasensor was successfully applied to thrombin sensing in real serum samples. PMID:27031188

  8. Conventional protein kinase C isoforms differentially regulate ADP- and thrombin-evoked Ca²⁺ signalling in human platelets.

    Lever, Robert A; Hussain, Azhar; Sun, Benjamin B; Sage, Stewart O; Harper, Alan G S

    2015-12-01

    Rises in cytosolic Ca(2+) concentration ([Ca(2+)]cyt) are central in platelet activation, yet many aspects of the underlying mechanisms are poorly understood. Most studies examine how experimental manipulations affect agonist-evoked rises in [Ca(2+)]cyt, but these only monitor the net effect of manipulations on the processes controlling [Ca(2+)]cyt (Ca(2+) buffering, sequestration, release, entry and removal), and cannot resolve the source of the Ca(2+) or the transporters or channels affected. To investigate the effects of protein kinase C (PKC) on platelet Ca(2+) signalling, we here monitor Ca(2+) flux around the platelet by measuring net Ca(2+) fluxes to or from the extracellular space and the intracellular Ca(2+) stores, which act as the major sources and sinks for Ca(2+) influx into and efflux from the cytosol, as well as monitoring the cytosolic Na(+) concentration ([Na(+)]cyt), which influences platelet Ca(2+) fluxes via Na(+)/Ca(2+) exchange. The intracellular store Ca(2+) concentration ([Ca(2+)]st) was monitored using Fluo-5N, the extracellular Ca(2+) concentration ([Ca(2+)]ext) was monitored using Fluo-4 whilst [Ca(2+)]cyt and [Na(+)]cyt were monitored using Fura-2 and SFBI, respectively. PKC inhibition using Ro-31-8220 or bisindolylmaleimide I potentiated ADP- and thrombin-evoked rises in [Ca(2+)]cyt in the absence of extracellular Ca(2+). PKC inhibition potentiated ADP-evoked but reduced thrombin-evoked intracellular Ca(2+) release and Ca(2+) removal into the extracellular medium. SERCA inhibition using thapsigargin and 2,5-di(tert-butyl) l,4-benzohydroquinone abolished the effect of PKC inhibitors on ADP-evoked changes in [Ca(2+)]cyt but only reduced the effect on thrombin-evoked responses. Thrombin evokes substantial rises in [Na(+)]cyt which would be expected to reduce Ca(2+) removal via the Na(+)/Ca(2+) exchanger (NCX). Thrombin-evoked rises in [Na(+)]cyt were potentiated by PKC inhibition, an effect which was not due to altered changes in non-selective cation permeability of the plasma membrane as assessed by Mn(2+) quench of Fura-2 fluorescence. PKC inhibition was without effect on thrombin-evoked rises in [Ca(2+)]cyt following SERCA inhibition and either removal of extracellular Na(+) or inhibition of Na(+)/K(+)-ATPase activity by removal of extracellular K(+) or treatment with digoxin. These data suggest that PKC limits ADP-evoked rises in [Ca(2+)]cyt by acceleration of SERCA activity, whilst rises in [Ca(2+)]cyt evoked by the stronger platelet activator thrombin are limited by PKC through acceleration of both SERCA and Na(+)/K(+)-ATPase activity, with the latter limiting the effect of thrombin on rises in [Na(+)]cyt and so forward mode NCX activity. The use of selective PKC inhibitors indicated that conventional and not novel PKC isoforms are responsible for the inhibition of agonist-evoked Ca(2+) signalling. PMID:26434503

  9. mRNA expression of genes involved in inflammation and haemostasis in equine fibroblast-like synoviocytes following exposure to lipopolysaccharide, fibrinogen and thrombin

    Andreassen, Stine Mandrup; Berg, Lise Charlotte; Nielsen, Søren Saxmose; Kristensen, Annemarie Thuri; Jacobsen, Stine

    2015-01-01

    Background: Studies in humans have shown that haemostatic and inflammatory pathways both play important roles in the pathogenesis of joint disease. The aim of this study was to assess mRNA expression of haemostatic and inflammatory factors in cultured equine fibroblast-like synoviocytes exposed to...... lipopolysaccharide (LPS), fibrinogen and thrombin. Synovial membranes were collected from metacarpo-phalangeal joints of 6 skeletally mature horses euthanized for non-orthopaedic reasons. Passage 4 fibroblast-like synoviocytes were left non-treated or treated with either 0.1 μ g/ml LPS, 5 mg/ml fibrinogen or 5 U......) and protease activator receptor 1 (PAR-1) was assessed using quantitative real time reverse transcriptase PCR. Results: LPS caused a significant increase in mRNA expression of SAA, IL-6, MCP-1 and uPA, and a decrease in TF, PAI-1 and PAR-1 when compared to non-treated cells. Treatment with thrombin...

  10. CRMAGE: CRISPR Optimized MAGE Recombineering.

    Ronda, Carlotta; Pedersen, Lasse Ebdrup; Sommer, Morten O A; Nielsen, Alex Toftgaard

    2016-01-01

    A bottleneck in metabolic engineering and systems biology approaches is the lack of efficient genome engineering technologies. Here, we combine CRISPR/Cas9 and ? Red recombineering based MAGE technology (CRMAGE) to create a highly efficient and fast method for genome engineering of Escherichia coli. Using CRMAGE, the recombineering efficiency was between 96.5% and 99.7% for gene recoding of three genomic targets, compared to between 0.68% and 5.4% using traditional recombineering. For modulation of protein synthesis (small insertion/RBS substitution) the efficiency was increased from 6% to 70%. CRMAGE can be multiplexed and enables introduction of at least two mutations in a single round of recombineering with similar efficiencies. PAM-independent loci were targeted using degenerate codons, thereby making it possible to modify any site in the genome. CRMAGE is based on two plasmids that are assembled by a USER-cloning approach enabling quick and cost efficient gRNA replacement. CRMAGE furthermore utilizes CRISPR/Cas9 for efficient plasmid curing, thereby enabling multiple engineering rounds per day. To facilitate the design process, a web-based tool was developed to predict both the ? Red oligos and the gRNAs. The CRMAGE platform enables highly efficient and fast genome editing and may open up promising prospective for automation of genome-scale engineering. PMID:26797514

  11. KEGG PATHWAY / Homologous recombination [KEGG

    Full Text Available PATHWAY: map03440 Entry map03440Pathway Name Homologous recombination Description Homologous rec ... drome mutated) are tumor suppressors that maintain genome ... integrity, at least in part, through HR. Class Gen ... 2MRX complex [PATH:map03440]M00295BRCA1-associated genome ... surveillance complex (BASC) [PATH:map03440] Diseas ...

  12. Recombination in immunoglobulin gene loci

    Komisarenko S. V.

    2009-02-01

    Full Text Available Gene network of the lymphoid cell differentiation coordinates precisely the recombination process in immunoglobulin gene loci. In our opinion, cellular microRNAs can contribute to the allelic exclusion through microRNA-directed DNA methylation and participate in retargeting recombinases activity from the gene loci of heavy immunoglobulin chains to the gene loci of light chains

  13. Recombination in immunoglobulin gene loci

    Komisarenko S. V.; Halytskiy V. A.

    2009-01-01

    Gene network of the lymphoid cell differentiation coordinates precisely the recombination process in immunoglobulin gene loci. In our opinion, cellular microRNAs can contribute to the allelic exclusion through microRNA-directed DNA methylation and participate in retargeting recombinases activity from the gene loci of heavy immunoglobulin chains to the gene loci of light chains

  14. [Role of exogenous fibrinogen in the processes of degranulation of thrombocytes stimulated with thrombin. Ultrastructural study using fibrinogen labeled with colloidal gold].

    Belitser, N V; Anishchuk, M G; Veklich, Iu I; Smekhova, T R; Pozdniakova, T M; Gorkun, O V; Chernyshenko, T M; Moroz, E D

    1992-01-01

    Using colloidal gold-conjugated fibrinogen (F-Au) it is shown that exogenous fibrinogen can participate in the platelet release reaction. In the absence of F-Au, internal secretory vacuoles readily formed in human platelets stimulated with thrombin, but extrusion of their content was delayed. Upon incubation with F-Au, endocytic channels induced by F-Au-receptor interactions, fused with internal vacuoles, thus establishing spatial communications of the latter with the outer medium. PMID:1621283

  15. Hypercoagulability in splenectomized thalassemic patients detected by whole-blood thromboelastometry, but not by thrombin generation in platelet-poor plasma

    TRIPODI,A; M.D.Cappellini; V. Chantarangkul; Padovan, L.; M.R. Fasulo; A. Marcon; P.M. Mannnucci

    2009-01-01

    The increased incidence of thrombosis in patients with thalassemia is likely to be driven primarily by the abnormal erythrocytes, an impression supported by the higher incidence following splenectomy. The importance of the cellular components of blood is strikingly supported by this study in which a prothrombotic state can be detected by whole blood thromboelastometry but not by thrombin generation in platelet poor plasma. See related perspective article on page 1481.

  16. Two subpopulations of thrombin-activated platelets differ in their binding of the components of the intrinsic factor X-activating complex.

    Panteleev, M A; Ananyeva, N M; Greco, N J; Ataullakhanov, F I; Saenko, E L

    2005-11-01

    Binding of fluorescein-labeled coagulation factors IXa, VIII, X, and allophycocyanin-labeled annexin V to thrombin-activated platelets was studied using flow cytometry. Upon activation, two platelet subpopulations were detected, which differed by 1-2 orders of magnitude in the binding of the coagulation factors and by 2-3 orders of magnitude in the binding of annexin V. The percentage of the high-binding platelets increased dose dependently of thrombin concentration. At 100 nm of thrombin, platelets with elevated binding capability constituted approximately 4% of total platelets and were responsible for the binding of approximately 50% of the total bound factor. Binding of factors to the high-binding subpopulation was calcium-dependent and specific as evidenced by experiments in the presence of excess unlabeled factor. The percentage of the high-binding platelets was not affected by echistatin, a potent aggregation inhibitor, confirming that the high-binding platelets were not platelet aggregates. Despite the difference in the coagulation factors binding, the subpopulations were indistinguishable by the expression of general platelet marker CD42b and activation markers PAC1 (an epitope of glycoprotein IIb/IIIa) and CD62P (P-selectin). Dual-labeling binding studies involving coagulation factors (IXa, VIII, or X) and annexin V demonstrated that the high-binding platelet subpopulation was identical for all coagulation factors and for annexin V. The high-binding subpopulation had lower mean forward and side scatters compared with the low-binding subpopulation ( approximately 80% and approximately 60%, respectively). In its turn, the high-binding subpopulation was not homogeneous and included two subpopulations with different scatter values. We conclude that activation by thrombin induces the formation of two distinct subpopulations of platelets different in their binding of the components of the intrinsic fX-activating complex, which may have certain physiological or pathological significance. PMID:16241952

  17. Design, synthesis and biological evaluation of new peptide-based ureas and thioureas as potential antagonists of the thrombin receptor PAR1

    Ventosa-Andrs, Pilar; Valdivielso, ngel M.; Pappos, Ioannis; Garcia-Lopez, M. Teresa; Tsopanoglou, Nikos E.; Herranz, Rosario

    2012-01-01

    By applying a diversity oriented synthesis strategy for the search of new antagonists of the thrombin receptor PAR1, a series of peptide-based ureas and thioureas, including analogues of the PAR1 reference antagonist RWJ-58259, has been designed and synthesized. The general synthetic scheme involves reduction of basic amino acid-derived amino nitriles by hydrogen transfer from hydrazine monohydrate in the presence of Raney Ni, followed by reaction with diverse isocyanates and isothiocyanates,...

  18. Pharmacodynamic and Efficacy Profile of TGN 255, a Novel Direct Thrombin Inhibitor, in Canine Cardiopulmonary Bypass and Simulated Mitral Valve Repair

    Nelson, David A.; Nelson, Katherine T.; Miller, Matthew W.; Dupe, Robert; Chahwala, Suresh B.; Kennedy, Anthony; Chander, Chaman; Theresa W. Fossum

    2008-01-01

    Heparin-induced thrombocytopenia can be a life-threatening sequel to conventional use of unfractionated heparin in cardiopulmonary bypass (CPB). This study evaluated the pharmacokinetic/pharmacodynamic (PK/PD) and efficacy profile of a novel direct thrombin inhibitor, TGN 255, during cardiac surgery in dogs. Point-of-care coagulation monitoring was also compared against the plasma concentrations of TRI 50c, the active metabolite of TGN 255. The study was conducted in three phases using 10 ani...

  19. Lack of nitric oxide- and guanosine 3?:5?-cyclic monophosphate-dependent regulation of ?-thrombin-induced calcium transient in endothelial cells of spontaneously hypertensive rat hearts

    Failli, Paola; Fazzini, Alessandro; Ruocco, Carlo; Mazzetti, Luca; Cecchi, Enrica; Giovannelli, Lisa; Marra, Fabio; Milani, Stefano; Giotti, Alberto

    2000-01-01

    While the expression and/or activity of endothelial nitric oxide synthase (eNOS) has been characterized in spontaneously hypertensive (SHR) and normotensive Wistar Kyoto rat (WKY) hearts, in coronary endothelial cells (ECs) from both strains, the effect of NO on intracellular calcium concentration ([Ca2+]i) is still unknown. Coronary microvascular ECs were isolated from SHR and WKY and characterized. Immunocytochemistry and Western blot analysis showed that eNOS was similarly expressed in ECs from both strains. Measuring [Ca2+]i by imaging analysis of fura-2-loaded cells, we demonstrated that ?-thrombin (3?180?U?l?1) induced a superimposable dose-dependent calcium transient in ECs from both strains. In WKY ECs, S-nitroso-N-acetyl-DL-penicillamine (SNAP) dose-dependently (10100??M) and 0.1??M atrial natriuretic factor (ANF) reduced the maximum and the decay time of ?-thrombin-induced calcium transient. The inhibitory effects of SNAP and ANF were prevented by blocking cyclic GMP-dependent protein kinase. Non selective eNOS inhibitors prolonged the decay time of ?-thrombin-induced calcium transient, while the selective inducible NOS inhibitor 1400?W was ineffective. SNAP (100??M) and 0.1??M ANF increased cyclic GMP content up to 22.9 and 42.3 fold respectively. In SHR ECs, ?-thrombin-induced calcium transient was not modified by SNAP, ANF or eNOS inhibition. SNAP (100??M) and 0.1??M ANF increased cyclic GMP content up to 9.3 and 51 fold respectively. In WKY ECs, SNAP dose-dependently (10100??M) reduced also bradykinin-induced calcium transient, while in SHR ECs was ineffective. We concluded that in SHR ECs, the cyclic GMP-dependent regulation of calcium transient is lost. PMID:10928946

  20. Recent Advances In Topical Therapy In Dermatology

    Mohan Thappa Devinder

    2003-01-01

    Full Text Available With changing times various newer topical agents are introduced in the field of dermatology. Tacrolimus and pimecrolimus are immunisuppressants, which are effective topically and are tried in the management of atopic dermatitis as well as other disorders including allergic contact dermatitis, atrophic lichen planus, pyoderma gangrenosum. Imiquimod, an immune response modifier, is presently in use for genital warts but has potentials as anti- tumour agent and in various other dermatological conditions when used topically. Tazarotene is a newer addition to the list of topical reginoids, which is effective in psoriasis and has better effect in combination with calcipotriene, phototherapy and topical costicosteroids. Tazarotene and adapelene are also effective in inflammatory acne. Calcipotriol, a vitamin D analogue has been introduced as a topical agent in the treatment of psoriasis. Steroid components are also developed recently which will be devoid of the side effects but having adequate anti-inflammatory effect. Topical photodynamic therapy has also a wide range of use in dermatology. Newer topical agents including cidofovir, capsaicin, topical sensitizers, topical antifungal agents for onychomycosis are also of use in clinical practice. Other promising developments include skin substitutes and growth factors for wound care.

  1. The Anopheles gambiae cE5, a tight- and fast-binding thrombin inhibitor with post-transcriptionally regulated salivary-restricted expression.

    Ronca, Raffaele; Kotsyfakis, Michalis; Lombardo, Fabrizio; Rizzo, Cinzia; Currà, Chiara; Ponzi, Marta; Fiorentino, Gabriella; Ribeiro, Josè M C; Arcà, Bruno

    2012-09-01

    Mosquito saliva carries a large number of factors with anti-hemostatic, anti-inflammatory and immuno-modulatory activities. The cE5 protein was initially identified during an Anopheles gambiae salivary gland transcriptome study and later shown to share sequence similarity with anophelin, a thrombin inhibitor from the saliva of the New World mosquito Anopheles albimanus. The cE5 gene was found to encode different mRNA isoforms coexisting in several tissues of both male and female mosquitoes, a highly unusual profile for a gene potentially encoding an anti-thrombin and involved in blood feeding. Expression of the cE5 protein and assessment of its activity and inhibitory properties showed that it is a highly specific and tight-binding thrombin inhibitor, which differs from the A. albimanus orthologue for the fast-binding kinetics. Despite the widespread occurrence of cE5 transcripts in different mosquito tissues the corresponding protein was only found in female salivary glands, where it undergoes post-translational modification. Therefore, tissue-specific restriction of the A. gambiae cE5 is not achieved by transcriptional control, as common for mosquito salivary genes involved in hematophagy, but by post-trascriptional gene regulatory mechanisms. Our observations provide a paradigm of post-transcriptional regulation as key determinant of tissue specificity for a protein from an important disease vector and point out that transcriptomic data should be interpreted with caution in the absence of concomitant proteomic support. PMID:22617725

  2. Genetics Home Reference: recombinant 8 syndrome

    ... copy of the recombinant chromosome 8 in each cell is sufficient to cause the disorder. Most people with recombinant 8 ... SL, Sample T, Bleskan J, Sujansky E, Patterson D. Cloning, sequencing, and analysis of inv8 chromosome breakpoints associated ...

  3. Variation in hospital resource use and cost among surgical procedures using topical absorbable hemostats

    Martyn D

    2015-11-01

    Full Text Available Derek Martyn,1 Lisa M Meckley,1 Gavin Miyasato,1 Sangtaeck Lim,2 Jerome B Riebman,3 Richard Kocharian,3 Jillian G Scaife,1 Yajing Rao,1 Mitra Corral2 1Trinity Partners, LLC, Waltham, MA, USA; 2Global Health Economics and Market Access, Ethicon, Inc., Bridgewater, NJ, USA; 3Medical Affairs, Ethicon, Inc., Bridgewater, NJ, USA Background: Adjunctive hemostats are used to assist with the control of intraoperative bleeding. The most common types are flowables, gelatins, thrombins, and oxidized regenerated celluloses (ORCs. In the US, Surgicel products are the only US Food and Drug Administration-approved ORCs. Objective: To compare the outcomes of health care resource utilization (HRU and costs associated with using ORCs compared to other adjunctive hemostats (OAHs are defined as flowables, gelatins, and topical thrombins for surgical procedures in the US inpatient setting. Patients and methods: A retrospective, US-based cohort study was conducted using hospital inpatient discharges from the 20112012 calendar years in the Premier Healthcare Database. Patients with either an ORC or an OAH who underwent a cardiovascular procedure (valve surgery and/or coronary artery bypass graft surgery, carotid endarterectomy, cholecystectomy, or hysterectomy were included. Propensity score matching was used to create comparable groups of ORC and OAH patients. Clinical, economic, and HRU outcomes were compared. Results: The propensity score matching created balanced patient cohorts for cardiovascular procedure (22,718 patients, carotid endarterectomy (10,890 patients, cholecystectomy (6,090 patients, and hysterectomy (9,348 patients. In all procedures, hemostatic agent costs were 28%56% lower for ORCs, and mean hemostat units per discharge were 16%41% lower for ORCs compared to OAHs. Length of stay and total procedure costs for patients treated with ORCs were lower for carotid endarterectomy patients (0.3 days and US$700 and for cholecystectomy patients (1 day and US$3,350 (all P<0.001. Conclusion: Costs and HRU for patients treated with ORCs were lower than or similar to patients treated with OAHs. Proper selection of the appropriate hemostatic agents has the potential to influence clinical outcomes and treatment costs. Keywords: hemostatics, hemostatic techniques, blood transfusion, health care costs, surgical blood loss

  4. Identifying Health-Related Topics on Twitter

    Prier, Kyle W.; Smith, Matthew S.; Giraud-Carrier, Christophe; Hanson, Carl L.

    Public health-related topics are difficult to identify in large conversational datasets like Twitter. This study examines how to model and discover public health topics and themes in tweets. Tobacco use is chosen as a test case to demonstrate the effectiveness of topic modeling via LDA across a large, representational dataset from the United States, as well as across a smaller subset that was seeded by tobacco-related queries. Topic modeling across the large dataset uncovers several public health-related topics, although tobacco is not detected by this method. However, topic modeling across the tobacco subset provides valuable insight about tobacco use in the United States. The methods used in this paper provide a possible toolset for public health researchers and practitioners to better understand public health problems through large datasets of conversational data.

  5. A Topic Modeling Toolbox Using Belief Propagation

    Zeng, Jia

    2012-01-01

    Latent Dirichlet allocation (LDA) is an important hierarchical Bayesian model for probabilistic topic modeling, which attracts worldwide interests and touches on many important applications in text mining, computer vision and computational biology. This paper introduces a topic modeling toolbox (TMBP) based on the belief propagation (BP) algorithms. TMBP toolbox is implemented by MEX C++/Matlab/Octave for either Windows 7 or Linux. Compared with existing topic modeling packages, the novelty o...

  6. Tracking topic birth and death in LDA.

    Wilson, Andrew T.; Robinson, David Gerald

    2011-09-01

    Most topic modeling algorithms that address the evolution of documents over time use the same number of topics at all times. This obscures the common occurrence in the data where new subjects arise and old ones diminish or disappear entirely. We propose an algorithm to model the birth and death of topics within an LDA-like framework. The user selects an initial number of topics, after which new topics are created and retired without further supervision. Our approach also accommodates many of the acceleration and parallelization schemes developed in recent years for standard LDA. In recent years, topic modeling algorithms such as latent semantic analysis (LSA)[17], latent Dirichlet allocation (LDA)[10] and their descendants have offered a powerful way to explore and interrogate corpora far too large for any human to grasp without assistance. Using such algorithms we are able to search for similar documents, model and track the volume of topics over time, search for correlated topics or model them with a hierarchy. Most of these algorithms are intended for use with static corpora where the number of documents and the size of the vocabulary are known in advance. Moreover, almost all current topic modeling algorithms fix the number of topics as one of the input parameters and keep it fixed across the entire corpus. While this is appropriate for static corpora, it becomes a serious handicap when analyzing time-varying data sets where topics come and go as a matter of course. This is doubly true for online algorithms that may not have the option of revising earlier results in light of new data. To be sure, these algorithms will account for changing data one way or another, but without the ability to adapt to structural changes such as entirely new topics they may do so in counterintuitive ways.

  7. [Recombination in Drosophila in space flight].

    Filatova, L P; Vaulina, E N; Lapteva, N Sh; Grozdova, T Ia

    1988-04-01

    An experiment with Drosophila melanogaster males was performed aboard the Artificial Satellite "Kosmos-1667". Mutagenic effects of a 7-day space flight on intergene recombination in chromosome 2 were studied. The space flight factors decreased the frequency of recombination. A model experiment on a laboratory centrifuge demonstrated insignificant increase in recombination frequency caused by acceleration. PMID:3135244

  8. Topical tacrolimus as treatment of atopic dermatitis

    Masutaka Furue

    2009-11-01

    Full Text Available Masutaka Furue, Satoshi TakeuchiDepartment of Dermatology, Faculty of Medical Sciences, Kyushu University, Fukuoka, JapanAbstract: Atopic dermatitis (AD is a common, chronic, relapsing, severely pruritic, eczematous skin disease. The mainstays of treatment for AD are topical tacrolimus and topical steroids. Tacrolimus, a calcineurin inhibitor, not only complements existing treatment options but also overcomes some of the drawbacks of topical steroid therapy when given topically and thus meets the long-term needs of patients in preventing disease progression. Topical tacrolimus has been widely recognized in terms of its short- and long-term efficacies and safety, and it is also accepted as a first-line treatment for inflammation in AD. The recent proactive use of topical tacrolimus may emphasize a long-term benefit of this calcineurin inhibitor for AD treatment. To reduce possible long-term adverse effects, it is important to monitor its topical doses in daily clinics.Keywords: atopic dermatitis, topical tacrolimus, topical steroids, dose, proactive use, adverse effects

  9. The treatment of rosacea with topical ivermectin.

    Ali, S T; Alinia, H; Feldman, S R

    2015-04-01

    The treatment of rosacea is challenging because several pathophysiologic processes may be involved, including neurovascular dysregulation and alterations in innate immune status. Demodex mites may play a role in the latter mechanism. Topical ivermectin is a new therapeutic modality which demonstrates antiparasitic and anti-inflammatory properties. This article reviews published evidence related to the efficacy and safety of topical ivermectin. PubMed was utilized to search for key words "topical ivermectin", "ivermectin cream" and "rosacea". Three clinical trials were found that studied topical ivermectin as a treatment option for rosacea. Ivermectin was effective, safe and well tolerated. PMID:26020066

  10. Workplace Safety and Health Topics: Safety & Prevention

    ... NIOSH Home Workplace Safety & Health Topics Share Compartir Safety & Prevention Adult Blood Lead Epidemiology and Surveillance (ABLES) Agricultural Safety and Injury Prevention Anthropometry Buy Quiet Cancer - NIOSH ...

  11. In vitro selection of human alpha-thrombin RNA aptamer using 4'-thioUTP and 4'-thioCTP.

    Kato, Yuka; Minakawa, Noriaki; Ogawa, Naoki; Matsuda, Akira

    2004-01-01

    We synthesized 4'-thioUTP (1) and 4'-thioCTP (2) with the aim of developing new NTP analogs for in vitro selection. Since in vitro selection requires both in vitro transcription and reverse transcription, we examined the ability of 1 and 2 for in vitro selection by focusing on both steps. Incorporation of 1 and 2 by T7 RNA polymerase to give 4'-thioRNA proceeded well and was superior to those of the two sets of frequently used modified NTP analogs (2'-NH2dUTP and 2'-NH2dCTP, and 2'-FdUTP and 2'-FdCTP) for in vitro selection. In addition, reverse transcription of the resulting 4'-thioRNA into the complementary DNA in the presence of dNTPs also proceeded smoothly and precisely. With these successful results in hand, in vitro selection of human a-thrombin RNA aptamer using 1 and 2 is in progress. PMID:17150559

  12. Quadruplex to Watson-Crick duplex transition of the thrombin binding aptamer: a fluorescence resonance energy transfer study

    Thermodynamic parameters of closing up of guanine-rich thrombin binding element, upon binding to K+ and Na+ ions to form quadruplexes and opening up of these quadruplexes upon binding to its complementary strand, were investigated. For this purpose, 15 mer deoxynucleotide, d(G2T2G2TGTG2T2G2), labeled with 5'-fluorescein and 3'-tetramethylrhodamine was taken and fluorescence resonance energy transfer was monitored as a function of either metal ions or complementary strand concentrations. Equilibrium association constant obtained from FRET studies demonstrates that K+ ions bind with higher affinity than the Na+ ions. The enthalpy changes, ?H, obtained from temperature dependence of equilibrium association constant studies revealed that formation of quadruplex upon binding of metal ions is primarily enthalpy driven. Binding studies of complementary strand to the quadruplex suggest that opening of a quadruplex in NaCl buffer in presence of the complementary strand is enthalpic as well as entropic driven and can occur easily, whereas opening of the same quadruplex in KCl buffer suffers from enthalpic barrier. Comparison of overall thermodynamic parameters along with kinetics studies indicates that, although quadruplexes cannot efficiently compete with duplex formation at physiological pH, they delay the association of two strands

  13. Common variants in the human platelet PAR4 thrombin receptor alter platelet function and differ by race

    Edelstein, Leonard C.; Simon, Lukas M.; Lindsay, Cory R.; Kong, Xianguo; Teruel-Montoya, Raúl; Tourdot, Benjamin E.; Chen, Edward S.; Ma, Lin; Coughlin, Shaun; Nieman, Marvin; Holinstat, Michael; Shaw, Chad A.

    2014-01-01

    Human platelets express 2 thrombin receptors: protease-activated receptor (PAR)-1 and PAR4. Recently, we reported 3.7-fold increased PAR4-mediated aggregation kinetics in platelets from black subjects compared with white subjects. We now show that platelets from blacks (n = 70) express 14% more PAR4 protein than those from whites (n = 84), but this difference is not associated with platelet PAR4 function. Quantitative trait locus analysis identified 3 common single nucleotide polymorphisms in the PAR4 gene (F2RL3) associated with PAR4-induced platelet aggregation. Among these single nucleotide polymorphisms, rs773902 determines whether residue 120 in transmembrane domain 2 is an alanine (Ala) or threonine (Thr). Compared with the Ala120 variant, Thr120 was more common in black subjects than in white subjects (63% vs 19%), was associated with higher PAR4-induced human platelet aggregation and Ca2+ flux, and generated greater inositol 1,4,5-triphosphate in transfected cells. A second, less frequent F2RL3 variant, Phe296Val, was only observed in blacks and abolished the enhanced PAR4-induced platelet aggregation and 1,4,5-triphosphate generation associated with PAR4-Thr120. PAR4 genotype did not affect vorapaxar inhibition of platelet PAR1 function, but a strong pharmacogenetic effect was observed with the PAR4-specific antagonist YD-3 [1-benzyl-3(ethoxycarbonylphenyl)-indazole]. These findings may have an important pharmacogenetic effect on the development of new PAR antagonists. PMID:25293779

  14. Effect of ethanol on thrombin-induced platelet phospholipid breakdown and release of [3H]-5-hydroxytryptamine

    Ethanol has been reported previously to inhibit chemically-induced platelet aggregation and the release of platelet contents. In platelet suspensions the mechanical stimulus of stirring can induce slow aggregation and the loss of endogenous arachidonic acid from phospholipids by activation of platelet phospholipases. These changes are prevented by the presence of ethanol 20-100 mM, whereas, in unstirred suspensions, ethanol alone has no effect on platelet phospholipids. Under similar conditions of reduced platelet: platelet contact, chemical stimuli, such as thrombi, although unable to produce visible aggregation, still cause the release of [3H]-5-hydroxytryptamine from platelets and also initiate the breakdown of platelet phospholipids. Ethanol does not now inhibit the thrombin-induced release of platelet contents and has little effect on phosphatidylinositol breakdown, though it inhibits phosphatidylcholine breakdown. Ethanol may therefore inhibit platelet aggregation by reducing the effect of mechanical and chemical stimuli on the activation of phospholipase A2. In contrast ethanol has rather little effect on the receptor-mediated breakdown of phosphatidylinositol which is apparently sufficient to trigger the release of platelet contents

  15. Recombinational substrates designed to study recombination between unique and repetitive sequences in vivo

    Three recombination events, reciprocal recombination, sister-chromatid recombination, and gene conversion, were studied using substrates designed in vitro. Each type of recombination event can be monitored at any chromosomal location. The authors have shown that sister-chromatid recombination is induced mitotically by DNA damaging agents, such as methyl methanesulfonate and γ-rays, but is decreased mitotically in strains defective in rad52. Reciprocal recombination by which circular plasmids integrate into the genome is unaffected by rad52 defective alleles and occurs by a different recombination pathway. Mechanisms are suggested by which gene conversion between sister chromatids can generate chromosome rearrangements

  16. Mechanisms of sister chromatid recombination

    Studies using T948 as a model system have been carried out aimed at elucidating the mechanism of sister chromatid recombination (SCR). Characterization of U.V. light- and x-ray-induced SCR, the relationiship between SCR induction and DNA repair using rad mutations, and the relationship between SCR induction and the time of cell division using cdc mutations are presented. It has been supposed that SCR is induced at the phase of S-G2 following DNA replication, that postreplication break of DNA strands is strongly involved in the induction of SCR, and that induction type of SCR, i.e., conversion type or recombination type, is dependent upon the type of molecular damage of DNA. (Namekawa, K.)

  17. Microbial factories for recombinant pharmaceuticals

    Domingo-Espn Joan; Ferrer-Miralles Neus; Corchero Jos; Vzquez Esther; Villaverde Antonio

    2009-01-01

    Abstract Most of the hosts used to produce the 151 recombinant pharmaceuticals so far approved for human use by the Food and Drug Administration (FDA) and/or by the European Medicines Agency (EMEA) are microbial cells, either bacteria or yeast. This fact indicates that despite the diverse bottlenecks and obstacles that microbial systems pose to the efficient production of functional mammalian proteins, namely lack or unconventional post-translational modifications, proteolytic instability, po...

  18. Detection of Quantitative Trait Loci Influencing Recombination Using Recombinant Inbred Lines

    Dole, Jefferey; Weber, David F.

    2007-01-01

    The genetic basis of variation in recombination in higher plants is polygenic and poorly understood, despite its theoretical and practical importance. Here a method of detecting quantitative trait loci (QTL) influencing recombination in recombinant inbred lines (RILs) is proposed that relies upon the fact that genotype data within RILs carry the signature of past recombination. Behavior of the segregational genetic variance in numbers of chromosomal crossovers (recombination) over generations...

  19. Workshop on Radio Recombination Lines

    1980-01-01

    Since their first detection 15 years ago, radio recombination lines from several elements have been observed in a wide variety of objects including HII regions, planetary nebulae, molecular clouds, the diffuse interstellar medium, and recently, other galaxies. The observations span almost the entire range from 0.1 to 100 GHz, and employ both single­ djsh and aperture synthesis techniques. The theory of radio recombination lines has also advanced strongly, to the point where it is perhaps one of the best-understood in astro­ physics. In a parallel development, it has become possible over the last decade to study these same highly-excited atoms in the laboratory; this work provides further confirmation of the theoretical framework. However there has been continuing controversy over the astrophysical interpre­ tation of radio recombination line observations, especially regarding the role of stimulated emission. A workshop was held in Ottawa on 24-25 August, 1979, bringing together many of the active scientist...

  20. Recombinant Factor IX Fc Fusion Protein Maintains Full Procoagulant Properties and Exhibits Prolonged Efficacy in Hemophilia B Mice

    Toby, Garabet G.; Liu, Tongyao; Buyue, Yang; Zhang, Xin; Bitonti, Alan J.; Pierce, Glenn F.; Sommer, Jurg M.; Jiang, Haiyan; Peters, Robert T.

    2016-01-01

    Introduction Hemophilia B is an inherited X chromosome–linked disorder characterized by impaired blood clotting owing to the absence of functional coagulation factor IX. Due to the relatively short half-life of factor IX, patients with hemophilia B require frequent factor IX infusions to maintain prophylaxis. We have developed a recombinant factor IX (rFIX) fused to the Fc region of IgG (rFIXFc) with an extended half-life in animals and humans. Materials and Methods Procoagulant properties of rFIXFc and rFIX (BENEFIX®) were compared to determine the effect of the Fc region on rFIXFc hemostatic function. Specifically, we assessed rFIXFc activation, intermolecular interactions within the Xase complex, inactivation by antithrombin III (AT) and thrombin generation potential compared with rFIX. We also assessed the acute and prophylactic efficacy profiles of rFIXFc and rFIX in vivo in hemophilia B mouse bleeding models. Results and Conclusions The activation by factor XIa or factor VIIa/tissue factor, inhibition by AT, interaction profiles with phospholipids, affinities for factor VIIIa within the context of the Xase complex, and thrombin generation profiles were similar for rFIXFc and rFIX. Xase complexes formed with either molecule exhibited similar kinetic profiles for factor Xa generation. In acute efficacy models, mice infused with rFIXFc or rFIX were equally protected from bleeding. However, in prophylactic efficacy models, protection from bleeding was maintained approximately three times longer in rFIXFc-dosed mice than in those given rFIX; this prolonged efficacy correlates with the previously observed half-life extension. We conclude that rFIXFc retains critical FIX procoagulant attributes and that the extension in rFIXFc half-life translates into prolonged efficacy in hemophilia B mice. PMID:26840952